improved

go.mod

@@ -1,18 +1,20 @@
 module taldl
 
-go 1.14
+go 1.16
 
 require (
-	github.com/PuerkitoBio/goquery v1.5.1 // indirect
-	github.com/antchfx/htmlquery v1.2.2 // indirect
-	github.com/antchfx/xmlquery v1.2.3 // indirect
-	github.com/antchfx/xpath v1.1.4 // indirect
+	github.com/PuerkitoBio/goquery v1.7.0 // indirect
+	github.com/antchfx/htmlquery v1.2.3 // indirect
+	github.com/antchfx/xmlquery v1.3.6 // indirect
 	github.com/gobwas/glob v0.2.3 // indirect
 	github.com/gocolly/colly v1.2.0
-	github.com/golang/groupcache v0.0.0-20200121045136-8c9f03a8e57e // indirect
+	github.com/ipfs/go-cid v0.0.7
+	github.com/ipfs/go-ipfs-api v0.2.0
+	github.com/ipfs/ipfs-cluster v0.13.3
 	github.com/kennygrant/sanitize v1.2.4 // indirect
+	github.com/multiformats/go-multiaddr v0.3.1
 	github.com/saintfish/chardet v0.0.0-20120816061221-3af4cd4741ca // indirect
-	github.com/temoto/robotstxt v1.1.1 // indirect
-	golang.org/x/net v0.0.0-20200324143707-d3edc9973b7e // indirect
-	google.golang.org/appengine v1.6.5 // indirect
+	github.com/schollz/progressbar/v3 v3.8.2
+	github.com/temoto/robotstxt v1.1.2 // indirect
+	google.golang.org/appengine v1.6.7 // indirect
 )

main.go

@@ -1,92 +1,221 @@
 package main
 
 import (
+	"archive/zip"
 	"context"
 	"encoding/json"
 	"flag"
 	"fmt"
+	"io"
 	"io/ioutil"
 	"net/http"
 	"os"
 	"os/user"
 	"path"
 	"path/filepath"
+	"strconv"
+	"strings"
+	"sync"
 	"time"
 
 	"github.com/gocolly/colly"
+	"github.com/schollz/progressbar/v3"
 )
 
-var store = "~/.taldl.json"
-
-var output = flag.String("output", "epub", "output directory")
-var format = flag.String("format", "epub", "format to download")
-
-func main() {
-	flag.Parse()
-
-	store = fixpath(store)
-	*output = fixpath(*output)
-
-	os.MkdirAll(*output, os.ModePerm)
-
-	oldMostRecent := ""
-	newMostRecent := ""
-
-	data, _ := ioutil.ReadFile(store)
-	_ = json.Unmarshal(data, &oldMostRecent)
-
-	done := false
-
-	c := colly.NewCollector()
-
-	c.OnHTML("div.amw-listing-item a[href]", func(e *colly.HTMLElement) {
-		url := e.Attr("href") + "." + *format
-
-		if newMostRecent == "" {
-			newMostRecent = url
-		}
-
-		if newMostRecent == oldMostRecent {
-			done = true
-			return
-		}
-
-		fmt.Println(url)
-
-		name := filenameForUrl(url)
-		path := *output + "/" + name
-
-		data, err := get(url, time.Second*3)
-		if err != nil {
-			fmt.Println(err)
-			return
-		}
-
-		err = ioutil.WriteFile(path, data, 0644)
-		if err != nil {
-			fmt.Println(err)
-		}
-	})
-
-	c.OnHTML("a[href] i.fa-chevron-right", func(e *colly.HTMLElement) {
-		next, _ := e.DOM.Parent().Attr("href")
-
-		if !done {
-			e.Request.Visit(next)
-		}
-	})
-
-	c.OnRequest(func(r *colly.Request) {
-		fmt.Println("Checking", r.URL)
-	})
-
-	c.Visit("https://theanarchistlibrary.org/latest")
-
-	data, _ = json.Marshal(newMostRecent)
-	_ = ioutil.WriteFile(store, data, 0644)
+type Cache struct {
+	MostRecent string
+	Pages      int
 }
 
-func fixpath(path string) string {
+var cacheFile = "~/.taldl.json"
+
+var outputDir = flag.String("output", "~/TAL", "output directory")
+var formats = flag.String("formats", "zip,epub,pdf,a4.pdf,lt.pdf", "formats to download")
+var progress = flag.Bool("progress", true, "show progress bar")
+var verbose = flag.Bool("verbose", true, "verbose output")
+var workers = flag.Int("workers", 5, "amount of workers")
+var update = flag.Bool("update", false, "update all entries")
+
+var mostRecent string
+var done bool
+var cache Cache
+var useFormat map[string]bool
+
+func main() {
+	var bar *progressbar.ProgressBar
+	var lastPage int
+	var hrefs = []string{}
+	var hrefsMutex sync.Mutex
+	var done bool
+
+	flag.Parse()
+
+	if *verbose {
+		fmt.Printf("writing to %s\r\n", *outputDir)
+	}
+
+	useFormat = make(map[string]bool)
+	fmts := strings.Split(*formats, ",")
+	for _, f := range fmts {
+		useFormat[f] = true
+	}
+
+	cacheFile = fixPath(cacheFile)
+	cacheData, _ := ioutil.ReadFile(cacheFile)
+	_ = json.Unmarshal(cacheData, &cache)
+
+	*outputDir = fixPath(*outputDir)
+
+	os.MkdirAll(*outputDir, os.ModePerm)
+
+	c := colly.NewCollector()
+	c.OnHTML("ul.pagination li:nth-last-child(2)", func(e *colly.HTMLElement) {
+		lastPage, _ = strconv.Atoi(strings.TrimSpace(e.Text))
+	})
+	c.OnHTML("div.amw-listing-item:nth-child(1) a[href]", func(e *colly.HTMLElement) {
+		href := e.Attr("href")
+		mostRecent = href
+	})
+	c.OnHTML("div.amw-listing-item a[href]", func(e *colly.HTMLElement) {
+		href := e.Attr("href")
+		if cache.MostRecent == href {
+			done = true
+		}
+		if !done || *update {
+			hrefs = append(hrefs, href)
+		}
+	})
+
+	url := "https://theanarchistlibrary.org/latest/1"
+	c.Visit(url)
+
+	newPages := 1
+
+	if *update {
+		newPages = lastPage
+	} else {
+		newPages = lastPage - cache.Pages
+	}
+
+	if newPages > 0 {
+		if *verbose {
+			fmt.Fprintf(os.Stderr, "Checking latest entries... \r\n")
+		}
+
+		if *progress {
+			bar = progressbar.Default(int64(newPages))
+			bar.Add(1)
+		}
+	}
+
+	scanJobs := make(chan int, newPages)
+	scanResults := make(chan []string, newPages)
+
+	for w := 1; w <= *workers; w++ {
+		go scanner(w, scanJobs, scanResults)
+	}
+	for a := 2; a <= newPages; a++ {
+		scanJobs <- a
+	}
+	close(scanJobs)
+
+	for a := 2; a <= newPages; a++ {
+		result := <-scanResults
+		hrefsMutex.Lock()
+		hrefs = append(hrefs, result...)
+		hrefsMutex.Unlock()
+		if *progress {
+			bar.Add(1)
+		}
+	}
+	close(scanResults)
+
+	cache.Pages = lastPage
+	cache.MostRecent = mostRecent
+
+	numJobs := len(hrefs)
+
+	if numJobs == 0 {
+		save(cache)
+		return
+	}
+
+	if *verbose {
+		fmt.Fprintf(os.Stderr, "Checking %d entries for updates...\r\n", numJobs)
+	}
+
+	if *progress {
+		bar = progressbar.Default(int64(numJobs))
+		bar.ChangeMax(numJobs)
+	}
+
+	checkJobs := make(chan string, numJobs)
+	checkResults := make(chan string, numJobs)
+	downloadJobs := make(chan string, numJobs)
+	downloadResults := make(chan string, numJobs)
+	downloadCount := 0
+
+	for w := 1; w <= *workers; w++ {
+		go checker(w, checkJobs, checkResults)
+	}
+	for _, href := range hrefs {
+		checkJobs <- href
+	}
+	close(checkJobs)
+
+	for a := 1; a <= numJobs; a++ {
+		r := <-checkResults
+		if *progress {
+			bar.Add(1)
+		}
+		if r != "" {
+			downloadJobs <- r
+			downloadCount++
+		}
+	}
+	close(checkResults)
+	close(downloadJobs)
+
+	if downloadCount == 0 {
+		save(cache)
+		return
+	}
+
+	if *verbose {
+		fmt.Fprintf(os.Stderr, "Downloading %d entries...\r\n", downloadCount)
+	}
+
+	if *progress {
+		bar = progressbar.Default(int64(downloadCount))
+	}
+
+	for w := 1; w <= *workers; w++ {
+		go downloader(w, downloadJobs, downloadResults)
+	}
+
+	buffer := ""
+
+	for a := 1; a <= downloadCount; a++ {
+		r := <-downloadResults
+		if *progress {
+			bar.Add(1)
+		}
+		if r != "" {
+			buffer += r
+		}
+	}
+	close(downloadResults)
+
+	save(cache)
+
+	if buffer != "" {
+		if *verbose {
+			fmt.Fprintln(os.Stderr, buffer)
+		}
+	}
+}
+
+func fixPath(path string) string {
 	path = filepath.FromSlash(path)
 	if (path)[0] == '~' {
 		user, err := user.Current()
@@ -104,13 +233,15 @@ func filenameForUrl(url string) string {
 	return path.Base(url)
 }
 
-func get(url string, timeout time.Duration) (content []byte, err error) {
-	request, err := http.NewRequest("GET", url, nil)
+func check(url string, path string, timeout time.Duration) (modified bool, err error) {
+	request, err := http.NewRequest("HEAD", url, nil)
 	if err != nil {
 		return
 	}
 
-	ctx, cancel_func := context.WithTimeout(context.Background(), timeout)
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+
 	request = request.WithContext(ctx)
 
 	response, err := http.DefaultClient.Do(request)
@@ -119,9 +250,65 @@ func get(url string, timeout time.Duration) (content []byte, err error) {
 	}
 	defer response.Body.Close()
 
+	if response.StatusCode == 404 {
+		return false, nil
+	}
+
 	if response.StatusCode != 200 {
-		cancel_func()
-		return nil, fmt.Errorf("INVALID RESPONSE: %s", response.Status)
+		return false, fmt.Errorf("%s: %s", url, response.Status)
+	}
+
+	lmh := response.Header.Get("Last-Modified")
+	lm, err := http.ParseTime(lmh)
+	if err != nil {
+		return true, err
+	}
+
+	file, err := os.Stat(path)
+	if err != nil {
+		return true, nil
+	}
+
+	clh := response.Header.Get("Content-Length")
+	cl, err := strconv.ParseInt(clh, 10, 0)
+	if err != nil {
+		return true, nil
+	}
+
+	if file.Size() != cl {
+		return true, nil
+	}
+
+	if lm.After(file.ModTime()) {
+		return true, nil
+	}
+
+	return false, nil
+}
+
+func get(url string, timeout time.Duration) (content []byte, err error) {
+	request, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return
+	}
+
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+
+	request = request.WithContext(ctx)
+
+	response, err := http.DefaultClient.Do(request)
+	if err != nil {
+		return
+	}
+	defer response.Body.Close()
+
+	if response.StatusCode == 404 {
+		return
+	}
+
+	if response.StatusCode != 200 {
+		return nil, fmt.Errorf("%s: %s", url, response.Status)
 	}
 
 	return ioutil.ReadAll(response.Body)
@@ -134,3 +321,202 @@ func fileExists(path string) bool {
 	}
 	return !info.IsDir()
 }
+
+func download(url string, path string) (err error) {
+	for {
+		data, err := get(url, time.Second*60)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "error: %s: %s\n", url, err)
+			time.Sleep(time.Second)
+			continue
+		}
+
+		err = ioutil.WriteFile(path, data, 0644)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "error: %s\n", err)
+			return err
+		}
+		break
+	}
+
+	return nil
+}
+
+func unzip(src string, dest string) ([]string, error) {
+	var filenames []string
+
+	r, err := zip.OpenReader(src)
+	if err != nil {
+		return filenames, err
+	}
+	defer r.Close()
+
+	for _, f := range r.File {
+		fpath := filepath.Join(dest, f.Name)
+
+		if !strings.HasPrefix(fpath, filepath.Clean(dest)+string(os.PathSeparator)) {
+			return filenames, fmt.Errorf("%s: bad file path", fpath)
+		}
+
+		filenames = append(filenames, fpath)
+
+		if f.FileInfo().IsDir() {
+			os.MkdirAll(fpath, os.ModePerm)
+			continue
+		}
+
+		if err = os.MkdirAll(filepath.Dir(fpath), os.ModePerm); err != nil {
+			return filenames, err
+		}
+
+		outFile, err := os.OpenFile(fpath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, f.Mode())
+		if err != nil {
+			return filenames, err
+		}
+
+		rc, err := f.Open()
+		if err != nil {
+			return filenames, err
+		}
+
+		_, err = io.Copy(outFile, rc)
+
+		outFile.Close()
+		rc.Close()
+
+		if err != nil {
+			return filenames, err
+		}
+	}
+	return filenames, nil
+}
+
+func downloader(id int, jobs <-chan string, results chan<- string) {
+
+	for href := range jobs {
+		result := ""
+		dir := filenameForUrl(href)
+		dest := filepath.Join(*outputDir, dir)
+		os.MkdirAll(dest, 0700)
+
+		downloadFormat(href, "zip", dest)
+		downloadFormat(href, "epub", dest)
+		downloadFormat(href, "pdf", dest)
+		downloadFormat(href, "a4.pdf", dest)
+		downloadFormat(href, "lt.pdf", dest)
+
+		if *verbose {
+			results <- result
+		} else {
+			results <- ""
+		}
+	}
+}
+
+func scanner(id int, jobs <-chan int, results chan<- []string) {
+	var result []string
+
+	c := colly.NewCollector()
+	c.OnHTML("div.amw-listing-item a[href]", func(e *colly.HTMLElement) {
+		href := e.Attr("href")
+		if cache.MostRecent == href {
+			done = true
+		}
+		if !done {
+			result = append(result, href)
+		}
+	})
+	c.AllowURLRevisit = true
+
+	for i := range jobs {
+		url := fmt.Sprintf("https://theanarchistlibrary.org/latest/%d", i)
+		for {
+			result = []string{}
+			err := c.Visit(url)
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "error: %s\n", err)
+				time.Sleep(time.Second)
+			} else {
+				break
+			}
+		}
+		results <- result
+	}
+}
+
+func checker(id int, jobs <-chan string, results chan<- string) {
+	var modified bool
+	var err error
+
+	for href := range jobs {
+		ext := "muse"
+		url := href + "." + ext
+		dir := filenameForUrl(href)
+		name := filenameForUrl(url)
+		path := filepath.Join(*outputDir, dir, name)
+
+		if !fileExists(path) {
+			results <- href
+			continue
+		}
+
+		for {
+			modified, err = check(url, path, time.Second*30)
+			if err != nil {
+				fmt.Fprintf(os.Stderr, "error: %s\n", err)
+				time.Sleep(time.Second)
+				continue
+			}
+			break
+		}
+
+		if modified {
+			results <- href
+		} else {
+			results <- ""
+		}
+	}
+}
+
+func save(cache Cache) {
+	cacheData, _ := json.Marshal(&cache)
+	_ = ioutil.WriteFile(cacheFile, cacheData, 0644)
+}
+
+func downloadFormat(href string, ext string, dest string) error {
+	if !useFormat[ext] {
+		return nil
+	}
+
+	url := href + "." + ext
+	name := filenameForUrl(url)
+
+	if ext == "zip" {
+		tmpDir, err := ioutil.TempDir(os.TempDir(), "taldl")
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "error: %s\n", err)
+			return err
+		}
+		path := filepath.Join(tmpDir, name)
+		err = download(url, path)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "error: %s\n", err)
+			return err
+		}
+		_, err = unzip(path, *outputDir)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "error: %s\n", err)
+			return err
+		}
+		os.RemoveAll(tmpDir)
+	} else {
+		path := filepath.Join(dest, name)
+		err := download(url, path)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "error: %s\n", err)
+			return err
+		}
+	}
+
+	return nil
+}

vendor/github.com/PuerkitoBio/goquery/.gitattributes

@@ -0,0 +1 @@
+testdata/* linguist-vendored

vendor/github.com/PuerkitoBio/goquery/.gitignore

@@ -0,0 +1,16 @@
+# editor temporary files
+*.sublime-*
+.DS_Store
+*.swp
+#*.*#
+tags
+
+# direnv config
+.env*
+
+# test binaries
+*.test
+
+# coverage and profilte outputs
+*.out
+

vendor/github.com/PuerkitoBio/goquery/.travis.yml

@@ -0,0 +1,31 @@
+arch:
+    - amd64
+    - ppc64le
+language: go
+
+go:
+    - 1.7.x
+    - 1.8.x
+    - 1.9.x
+    - 1.10.x
+    - 1.11.x
+    - 1.12.x
+    - 1.13.x
+    - 1.14.x
+    - 1.15.x
+    - tip
+
+jobs:
+ exclude:
+    - arch: ppc64le
+      go: 1.7.x
+    - arch: ppc64le
+      go: 1.8.x
+    - arch: ppc64le
+      go: 1.9.x
+    - arch: ppc64le
+      go: 1.10.x
+    - arch: ppc64le
+      go: 1.11.x
+    - arch: ppc64le
+      go: 1.12.x

vendor/github.com/PuerkitoBio/goquery/LICENSE

@@ -0,0 +1,12 @@
+Copyright (c) 2012-2021, Martin Angers & Contributors
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
+
+* Neither the name of the author nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/github.com/PuerkitoBio/goquery/README.md

@@ -0,0 +1,190 @@
+# goquery - a little like that j-thing, only in Go
+[![builds.sr.ht status](https://builds.sr.ht/~mna/goquery/commits/fedora.yml.svg)](https://builds.sr.ht/~mna/goquery/commits/fedora.yml?) [![build status](https://secure.travis-ci.org/PuerkitoBio/goquery.svg?branch=master)](http://travis-ci.org/PuerkitoBio/goquery) [![Go Reference](https://pkg.go.dev/badge/github.com/PuerkitoBio/goquery.svg)](https://pkg.go.dev/github.com/PuerkitoBio/goquery) [![Sourcegraph Badge](https://sourcegraph.com/github.com/PuerkitoBio/goquery/-/badge.svg)](https://sourcegraph.com/github.com/PuerkitoBio/goquery?badge)
+
+goquery brings a syntax and a set of features similar to [jQuery][] to the [Go language][go]. It is based on Go's [net/html package][html] and the CSS Selector library [cascadia][]. Since the net/html parser returns nodes, and not a full-featured DOM tree, jQuery's stateful manipulation functions (like height(), css(), detach()) have been left off.
+
+Also, because the net/html parser requires UTF-8 encoding, so does goquery: it is the caller's responsibility to ensure that the source document provides UTF-8 encoded HTML. See the [wiki][] for various options to do this.
+
+Syntax-wise, it is as close as possible to jQuery, with the same function names when possible, and that warm and fuzzy chainable interface. jQuery being the ultra-popular library that it is, I felt that writing a similar HTML-manipulating library was better to follow its API than to start anew (in the same spirit as Go's `fmt` package), even though some of its methods are less than intuitive (looking at you, [index()][index]...).
+
+## Table of Contents
+
+* [Installation](#installation)
+* [Changelog](#changelog)
+* [API](#api)
+* [Examples](#examples)
+* [Related Projects](#related-projects)
+* [Support](#support)
+* [License](#license)
+
+## Installation
+
+Please note that because of the net/html dependency, goquery requires Go1.1+ and is tested on Go1.7+.
+
+    $ go get github.com/PuerkitoBio/goquery
+
+(optional) To run unit tests:
+
+    $ cd $GOPATH/src/github.com/PuerkitoBio/goquery
+    $ go test
+
+(optional) To run benchmarks (warning: it runs for a few minutes):
+
+    $ cd $GOPATH/src/github.com/PuerkitoBio/goquery
+    $ go test -bench=".*"
+
+## Changelog
+
+**Note that goquery's API is now stable, and will not break.**
+
+*    **2021-06-14 (v1.7.0)** : Add `Single` and `SingleMatcher` functions to optimize first-match selection (thanks [@gdollardollar](https://github.com/gdollardollar)).
+*    **2021-01-11 (v1.6.1)** : Fix panic when calling `{Prepend,Append,Set}Html` on a `Selection` that contains non-Element nodes.
+*    **2020-10-08 (v1.6.0)** : Parse html in context of the container node for all functions that deal with html strings (`AfterHtml`, `AppendHtml`, etc.). Thanks to [@thiemok][thiemok] and [@davidjwilkins][djw] for their work on this.
+*    **2020-02-04 (v1.5.1)** : Update module dependencies.
+*    **2018-11-15 (v1.5.0)** : Go module support (thanks @Zaba505).
+*    **2018-06-07 (v1.4.1)** : Add `NewDocumentFromReader` examples.
+*    **2018-03-24 (v1.4.0)** : Deprecate `NewDocument(url)` and `NewDocumentFromResponse(response)`.
+*    **2018-01-28 (v1.3.0)** : Add `ToEnd` constant to `Slice` until the end of the selection (thanks to @davidjwilkins for raising the issue).
+*    **2018-01-11 (v1.2.0)** : Add `AddBack*` and deprecate `AndSelf` (thanks to @davidjwilkins).
+*    **2017-02-12 (v1.1.0)** : Add `SetHtml` and `SetText` (thanks to @glebtv).
+*    **2016-12-29 (v1.0.2)** : Optimize allocations for `Selection.Text` (thanks to @radovskyb).
+*    **2016-08-28 (v1.0.1)** : Optimize performance for large documents.
+*    **2016-07-27 (v1.0.0)** : Tag version 1.0.0.
+*    **2016-06-15** : Invalid selector strings internally compile to a `Matcher` implementation that never matches any node (instead of a panic). So for example, `doc.Find("~")` returns an empty `*Selection` object.
+*    **2016-02-02** : Add `NodeName` utility function similar to the DOM's `nodeName` property. It returns the tag name of the first element in a selection, and other relevant values of non-element nodes (see [doc][] for details). Add `OuterHtml` utility function similar to the DOM's `outerHTML` property (named `OuterHtml` in small caps for consistency with the existing `Html` method on the `Selection`).
+*    **2015-04-20** : Add `AttrOr` helper method to return the attribute's value or a default value if absent. Thanks to [piotrkowalczuk][piotr].
+*    **2015-02-04** : Add more manipulation functions - Prepend* - thanks again to [Andrew Stone][thatguystone].
+*    **2014-11-28** : Add more manipulation functions - ReplaceWith*, Wrap* and Unwrap - thanks again to [Andrew Stone][thatguystone].
+*    **2014-11-07** : Add manipulation functions (thanks to [Andrew Stone][thatguystone]) and `*Matcher` functions, that receive compiled cascadia selectors instead of selector strings, thus avoiding potential panics thrown by goquery via `cascadia.MustCompile` calls. This results in better performance (selectors can be compiled once and reused) and more idiomatic error handling (you can handle cascadia's compilation errors, instead of recovering from panics, which had been bugging me for a long time). Note that the actual type expected is a `Matcher` interface, that `cascadia.Selector` implements. Other matcher implementations could be used.
+*    **2014-11-06** : Change import paths of net/html to golang.org/x/net/html (see https://groups.google.com/forum/#!topic/golang-nuts/eD8dh3T9yyA). Make sure to update your code to use the new import path too when you call goquery with `html.Node`s.
+*    **v0.3.2** : Add `NewDocumentFromReader()` (thanks jweir) which allows creating a goquery document from an io.Reader.
+*    **v0.3.1** : Add `NewDocumentFromResponse()` (thanks assassingj) which allows creating a goquery document from an http response.
+*    **v0.3.0** : Add `EachWithBreak()` which allows to break out of an `Each()` loop by returning false. This function was added instead of changing the existing `Each()` to avoid breaking compatibility.
+*    **v0.2.1** : Make go-getable, now that [go.net/html is Go1.0-compatible][gonet] (thanks to @matrixik for pointing this out).
+*    **v0.2.0** : Add support for negative indices in Slice(). **BREAKING CHANGE** `Document.Root` is removed, `Document` is now a `Selection` itself (a selection of one, the root element, just like `Document.Root` was before). Add jQuery's Closest() method.
+*    **v0.1.1** : Add benchmarks to use as baseline for refactorings, refactor Next...() and Prev...() methods to use the new html package's linked list features (Next/PrevSibling, FirstChild). Good performance boost (40+% in some cases).
+*    **v0.1.0** : Initial release.
+
+## API
+
+goquery exposes two structs, `Document` and `Selection`, and the `Matcher` interface. Unlike jQuery, which is loaded as part of a DOM document, and thus acts on its containing document, goquery doesn't know which HTML document to act upon. So it needs to be told, and that's what the `Document` type is for. It holds the root document node as the initial Selection value to manipulate.
+
+jQuery often has many variants for the same function (no argument, a selector string argument, a jQuery object argument, a DOM element argument, ...). Instead of exposing the same features in goquery as a single method with variadic empty interface arguments, statically-typed signatures are used following this naming convention:
+
+*    When the jQuery equivalent can be called with no argument, it has the same name as jQuery for the no argument signature (e.g.: `Prev()`), and the version with a selector string argument is called `XxxFiltered()` (e.g.: `PrevFiltered()`)
+*    When the jQuery equivalent **requires** one argument, the same name as jQuery is used for the selector string version (e.g.: `Is()`)
+*    The signatures accepting a jQuery object as argument are defined in goquery as `XxxSelection()` and take a `*Selection` object as argument (e.g.: `FilterSelection()`)
+*    The signatures accepting a DOM element as argument in jQuery are defined in goquery as `XxxNodes()` and take a variadic argument of type `*html.Node` (e.g.: `FilterNodes()`)
+*    The signatures accepting a function as argument in jQuery are defined in goquery as `XxxFunction()` and take a function as argument (e.g.: `FilterFunction()`)
+*    The goquery methods that can be called with a selector string have a corresponding version that take a `Matcher` interface and are defined as `XxxMatcher()` (e.g.: `IsMatcher()`)
+
+Utility functions that are not in jQuery but are useful in Go are implemented as functions (that take a `*Selection` as parameter), to avoid a potential naming clash on the `*Selection`'s methods (reserved for jQuery-equivalent behaviour).
+
+The complete [package reference documentation can be found here][doc].
+
+Please note that Cascadia's selectors do not necessarily match all supported selectors of jQuery (Sizzle). See the [cascadia project][cascadia] for details. Invalid selector strings compile to a `Matcher` that fails to match any node. Behaviour of the various functions that take a selector string as argument follows from that fact, e.g. (where `~` is an invalid selector string):
+
+* `Find("~")` returns an empty selection because the selector string doesn't match anything.
+* `Add("~")` returns a new selection that holds the same nodes as the original selection, because it didn't add any node (selector string didn't match anything).
+* `ParentsFiltered("~")` returns an empty selection because the selector string doesn't match anything.
+* `ParentsUntil("~")` returns all parents of the selection because the selector string didn't match any element to stop before the top element.
+
+## Examples
+
+See some tips and tricks in the [wiki][].
+
+Adapted from example_test.go:
+
+```Go
+package main
+
+import (
+  "fmt"
+  "log"
+  "net/http"
+
+  "github.com/PuerkitoBio/goquery"
+)
+
+func ExampleScrape() {
+  // Request the HTML page.
+  res, err := http.Get("http://metalsucks.net")
+  if err != nil {
+    log.Fatal(err)
+  }
+  defer res.Body.Close()
+  if res.StatusCode != 200 {
+    log.Fatalf("status code error: %d %s", res.StatusCode, res.Status)
+  }
+
+  // Load the HTML document
+  doc, err := goquery.NewDocumentFromReader(res.Body)
+  if err != nil {
+    log.Fatal(err)
+  }
+
+  // Find the review items
+  doc.Find(".left-content article .post-title").Each(func(i int, s *goquery.Selection) {
+		// For each item found, get the title
+		title := s.Find("a").Text()
+		fmt.Printf("Review %d: %s\n", i, title)
+	})
+}
+
+func main() {
+  ExampleScrape()
+}
+```
+
+## Related Projects
+
+- [Goq][goq], an HTML deserialization and scraping library based on goquery and struct tags.
+- [andybalholm/cascadia][cascadia], the CSS selector library used by goquery.
+- [suntong/cascadia][cascadiacli], a command-line interface to the cascadia CSS selector library, useful to test selectors.
+- [gocolly/colly](https://github.com/gocolly/colly), a lightning fast and elegant Scraping Framework
+- [gnulnx/goperf](https://github.com/gnulnx/goperf), a website performance test tool that also fetches static assets.
+- [MontFerret/ferret](https://github.com/MontFerret/ferret), declarative web scraping.
+- [tacusci/berrycms](https://github.com/tacusci/berrycms), a modern simple to use CMS with easy to write plugins
+- [Dataflow kit](https://github.com/slotix/dataflowkit), Web Scraping framework for Gophers.
+- [Geziyor](https://github.com/geziyor/geziyor), a fast web crawling & scraping framework for Go. Supports JS rendering.
+- [Pagser](https://github.com/foolin/pagser), a simple, easy, extensible, configurable HTML parser to struct based on goquery and struct tags.
+- [stitcherd](https://github.com/vhodges/stitcherd), A server for doing server side includes using css selectors and DOM updates.
+
+## Support
+
+There are a number of ways you can support the project:
+
+* Use it, star it, build something with it, spread the word!
+  - If you do build something open-source or otherwise publicly-visible, let me know so I can add it to the [Related Projects](#related-projects) section!
+* Raise issues to improve the project (note: doc typos and clarifications are issues too!)
+  - Please search existing issues before opening a new one - it may have already been adressed.
+* Pull requests: please discuss new code in an issue first, unless the fix is really trivial.
+  - Make sure new code is tested.
+  - Be mindful of existing code - PRs that break existing code have a high probability of being declined, unless it fixes a serious issue.
+* Sponsor the developer
+  - See the Github Sponsor button at the top of the repo on github
+  - or via BuyMeACoffee.com, below
+
+<a href="https://www.buymeacoffee.com/mna" target="_blank"><img src="https://www.buymeacoffee.com/assets/img/custom_images/orange_img.png" alt="Buy Me A Coffee" style="height: 41px !important;width: 174px !important;box-shadow: 0px 3px 2px 0px rgba(190, 190, 190, 0.5) !important;-webkit-box-shadow: 0px 3px 2px 0px rgba(190, 190, 190, 0.5) !important;" ></a>
+
+## License
+
+The [BSD 3-Clause license][bsd], the same as the [Go language][golic]. Cascadia's license is [here][caslic].
+
+[jquery]: http://jquery.com/
+[go]: http://golang.org/
+[cascadia]: https://github.com/andybalholm/cascadia
+[cascadiacli]: https://github.com/suntong/cascadia
+[bsd]: http://opensource.org/licenses/BSD-3-Clause
+[golic]: http://golang.org/LICENSE
+[caslic]: https://github.com/andybalholm/cascadia/blob/master/LICENSE
+[doc]: https://pkg.go.dev/github.com/PuerkitoBio/goquery
+[index]: http://api.jquery.com/index/
+[gonet]: https://github.com/golang/net/
+[html]: https://pkg.go.dev/golang.org/x/net/html
+[wiki]: https://github.com/PuerkitoBio/goquery/wiki/Tips-and-tricks
+[thatguystone]: https://github.com/thatguystone
+[piotr]: https://github.com/piotrkowalczuk
+[goq]: https://github.com/andrewstuart/goq
+[thiemok]: https://github.com/thiemok
+[djw]: https://github.com/davidjwilkins

vendor/github.com/PuerkitoBio/goquery/array.go

@@ -0,0 +1,124 @@
+package goquery
+
+import (
+	"golang.org/x/net/html"
+)
+
+const (
+	maxUint = ^uint(0)
+	maxInt  = int(maxUint >> 1)
+
+	// ToEnd is a special index value that can be used as end index in a call
+	// to Slice so that all elements are selected until the end of the Selection.
+	// It is equivalent to passing (*Selection).Length().
+	ToEnd = maxInt
+)
+
+// First reduces the set of matched elements to the first in the set.
+// It returns a new Selection object, and an empty Selection object if the
+// the selection is empty.
+func (s *Selection) First() *Selection {
+	return s.Eq(0)
+}
+
+// Last reduces the set of matched elements to the last in the set.
+// It returns a new Selection object, and an empty Selection object if
+// the selection is empty.
+func (s *Selection) Last() *Selection {
+	return s.Eq(-1)
+}
+
+// Eq reduces the set of matched elements to the one at the specified index.
+// If a negative index is given, it counts backwards starting at the end of the
+// set. It returns a new Selection object, and an empty Selection object if the
+// index is invalid.
+func (s *Selection) Eq(index int) *Selection {
+	if index < 0 {
+		index += len(s.Nodes)
+	}
+
+	if index >= len(s.Nodes) || index < 0 {
+		return newEmptySelection(s.document)
+	}
+
+	return s.Slice(index, index+1)
+}
+
+// Slice reduces the set of matched elements to a subset specified by a range
+// of indices. The start index is 0-based and indicates the index of the first
+// element to select. The end index is 0-based and indicates the index at which
+// the elements stop being selected (the end index is not selected).
+//
+// The indices may be negative, in which case they represent an offset from the
+// end of the selection.
+//
+// The special value ToEnd may be specified as end index, in which case all elements
+// until the end are selected. This works both for a positive and negative start
+// index.
+func (s *Selection) Slice(start, end int) *Selection {
+	if start < 0 {
+		start += len(s.Nodes)
+	}
+	if end == ToEnd {
+		end = len(s.Nodes)
+	} else if end < 0 {
+		end += len(s.Nodes)
+	}
+	return pushStack(s, s.Nodes[start:end])
+}
+
+// Get retrieves the underlying node at the specified index.
+// Get without parameter is not implemented, since the node array is available
+// on the Selection object.
+func (s *Selection) Get(index int) *html.Node {
+	if index < 0 {
+		index += len(s.Nodes) // Negative index gets from the end
+	}
+	return s.Nodes[index]
+}
+
+// Index returns the position of the first element within the Selection object
+// relative to its sibling elements.
+func (s *Selection) Index() int {
+	if len(s.Nodes) > 0 {
+		return newSingleSelection(s.Nodes[0], s.document).PrevAll().Length()
+	}
+	return -1
+}
+
+// IndexSelector returns the position of the first element within the
+// Selection object relative to the elements matched by the selector, or -1 if
+// not found.
+func (s *Selection) IndexSelector(selector string) int {
+	if len(s.Nodes) > 0 {
+		sel := s.document.Find(selector)
+		return indexInSlice(sel.Nodes, s.Nodes[0])
+	}
+	return -1
+}
+
+// IndexMatcher returns the position of the first element within the
+// Selection object relative to the elements matched by the matcher, or -1 if
+// not found.
+func (s *Selection) IndexMatcher(m Matcher) int {
+	if len(s.Nodes) > 0 {
+		sel := s.document.FindMatcher(m)
+		return indexInSlice(sel.Nodes, s.Nodes[0])
+	}
+	return -1
+}
+
+// IndexOfNode returns the position of the specified node within the Selection
+// object, or -1 if not found.
+func (s *Selection) IndexOfNode(node *html.Node) int {
+	return indexInSlice(s.Nodes, node)
+}
+
+// IndexOfSelection returns the position of the first node in the specified
+// Selection object within this Selection object, or -1 if not found.
+func (s *Selection) IndexOfSelection(sel *Selection) int {
+	if sel != nil && len(sel.Nodes) > 0 {
+		return indexInSlice(s.Nodes, sel.Nodes[0])
+	}
+	return -1
+}

vendor/github.com/PuerkitoBio/goquery/doc.go

@@ -0,0 +1,123 @@
+// Copyright (c) 2012-2016, Martin Angers & Contributors
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification,
+// are permitted provided that the following conditions are met:
+//
+// * Redistributions of source code must retain the above copyright notice,
+// this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above copyright notice,
+// this list of conditions and the following disclaimer in the documentation and/or
+// other materials provided with the distribution.
+// * Neither the name of the author nor the names of its contributors may be used to
+// endorse or promote products derived from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS
+// OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+// AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+// WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
+// WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+/*
+Package goquery implements features similar to jQuery, including the chainable
+syntax, to manipulate and query an HTML document.
+
+It brings a syntax and a set of features similar to jQuery to the Go language.
+It is based on Go's net/html package and the CSS Selector library cascadia.
+Since the net/html parser returns nodes, and not a full-featured DOM
+tree, jQuery's stateful manipulation functions (like height(), css(), detach())
+have been left off.
+
+Also, because the net/html parser requires UTF-8 encoding, so does goquery: it is
+the caller's responsibility to ensure that the source document provides UTF-8 encoded HTML.
+See the repository's wiki for various options on how to do this.
+
+Syntax-wise, it is as close as possible to jQuery, with the same method names when
+possible, and that warm and fuzzy chainable interface. jQuery being the
+ultra-popular library that it is, writing a similar HTML-manipulating
+library was better to follow its API than to start anew (in the same spirit as
+Go's fmt package), even though some of its methods are less than intuitive (looking
+at you, index()...).
+
+It is hosted on GitHub, along with additional documentation in the README.md
+file: https://github.com/puerkitobio/goquery
+
+Please note that because of the net/html dependency, goquery requires Go1.1+.
+
+The various methods are split into files based on the category of behavior.
+The three dots (...) indicate that various "overloads" are available.
+
+* array.go : array-like positional manipulation of the selection.
+    - Eq()
+    - First()
+    - Get()
+    - Index...()
+    - Last()
+    - Slice()
+
+* expand.go : methods that expand or augment the selection's set.
+    - Add...()
+    - AndSelf()
+    - Union(), which is an alias for AddSelection()
+
+* filter.go : filtering methods, that reduce the selection's set.
+    - End()
+    - Filter...()
+    - Has...()
+    - Intersection(), which is an alias of FilterSelection()
+    - Not...()
+
+* iteration.go : methods to loop over the selection's nodes.
+    - Each()
+    - EachWithBreak()
+    - Map()
+
+* manipulation.go : methods for modifying the document
+    - After...()
+    - Append...()
+    - Before...()
+    - Clone()
+    - Empty()
+    - Prepend...()
+    - Remove...()
+    - ReplaceWith...()
+    - Unwrap()
+    - Wrap...()
+    - WrapAll...()
+    - WrapInner...()
+
+* property.go : methods that inspect and get the node's properties values.
+    - Attr*(), RemoveAttr(), SetAttr()
+    - AddClass(), HasClass(), RemoveClass(), ToggleClass()
+    - Html()
+    - Length()
+    - Size(), which is an alias for Length()
+    - Text()
+
+* query.go : methods that query, or reflect, a node's identity.
+    - Contains()
+    - Is...()
+
+* traversal.go : methods to traverse the HTML document tree.
+    - Children...()
+    - Contents()
+    - Find...()
+    - Next...()
+    - Parent[s]...()
+    - Prev...()
+    - Siblings...()
+
+* type.go : definition of the types exposed by goquery.
+    - Document
+    - Selection
+    - Matcher
+
+* utilities.go : definition of helper functions (and not methods on a *Selection)
+that are not part of jQuery, but are useful to goquery.
+    - NodeName
+    - OuterHtml
+*/
+package goquery

vendor/github.com/PuerkitoBio/goquery/expand.go

@@ -0,0 +1,70 @@
+package goquery
+
+import "golang.org/x/net/html"
+
+// Add adds the selector string's matching nodes to those in the current
+// selection and returns a new Selection object.
+// The selector string is run in the context of the document of the current
+// Selection object.
+func (s *Selection) Add(selector string) *Selection {
+	return s.AddNodes(findWithMatcher([]*html.Node{s.document.rootNode}, compileMatcher(selector))...)
+}
+
+// AddMatcher adds the matcher's matching nodes to those in the current
+// selection and returns a new Selection object.
+// The matcher is run in the context of the document of the current
+// Selection object.
+func (s *Selection) AddMatcher(m Matcher) *Selection {
+	return s.AddNodes(findWithMatcher([]*html.Node{s.document.rootNode}, m)...)
+}
+
+// AddSelection adds the specified Selection object's nodes to those in the
+// current selection and returns a new Selection object.
+func (s *Selection) AddSelection(sel *Selection) *Selection {
+	if sel == nil {
+		return s.AddNodes()
+	}
+	return s.AddNodes(sel.Nodes...)
+}
+
+// Union is an alias for AddSelection.
+func (s *Selection) Union(sel *Selection) *Selection {
+	return s.AddSelection(sel)
+}
+
+// AddNodes adds the specified nodes to those in the
+// current selection and returns a new Selection object.
+func (s *Selection) AddNodes(nodes ...*html.Node) *Selection {
+	return pushStack(s, appendWithoutDuplicates(s.Nodes, nodes, nil))
+}
+
+// AndSelf adds the previous set of elements on the stack to the current set.
+// It returns a new Selection object containing the current Selection combined
+// with the previous one.
+// Deprecated: This function has been deprecated and is now an alias for AddBack().
+func (s *Selection) AndSelf() *Selection {
+	return s.AddBack()
+}
+
+// AddBack adds the previous set of elements on the stack to the current set.
+// It returns a new Selection object containing the current Selection combined
+// with the previous one.
+func (s *Selection) AddBack() *Selection {
+	return s.AddSelection(s.prevSel)
+}
+
+// AddBackFiltered reduces the previous set of elements on the stack to those that
+// match the selector string, and adds them to the current set.
+// It returns a new Selection object containing the current Selection combined
+// with the filtered previous one
+func (s *Selection) AddBackFiltered(selector string) *Selection {
+	return s.AddSelection(s.prevSel.Filter(selector))
+}
+
+// AddBackMatcher reduces the previous set of elements on the stack to those that match
+// the mateher, and adds them to the curernt set.
+// It returns a new Selection object containing the current Selection combined
+// with the filtered previous one
+func (s *Selection) AddBackMatcher(m Matcher) *Selection {
+	return s.AddSelection(s.prevSel.FilterMatcher(m))
+}

vendor/github.com/PuerkitoBio/goquery/filter.go

@@ -0,0 +1,163 @@
+package goquery
+
+import "golang.org/x/net/html"
+
+// Filter reduces the set of matched elements to those that match the selector string.
+// It returns a new Selection object for this subset of matching elements.
+func (s *Selection) Filter(selector string) *Selection {
+	return s.FilterMatcher(compileMatcher(selector))
+}
+
+// FilterMatcher reduces the set of matched elements to those that match
+// the given matcher. It returns a new Selection object for this subset
+// of matching elements.
+func (s *Selection) FilterMatcher(m Matcher) *Selection {
+	return pushStack(s, winnow(s, m, true))
+}
+
+// Not removes elements from the Selection that match the selector string.
+// It returns a new Selection object with the matching elements removed.
+func (s *Selection) Not(selector string) *Selection {
+	return s.NotMatcher(compileMatcher(selector))
+}
+
+// NotMatcher removes elements from the Selection that match the given matcher.
+// It returns a new Selection object with the matching elements removed.
+func (s *Selection) NotMatcher(m Matcher) *Selection {
+	return pushStack(s, winnow(s, m, false))
+}
+
+// FilterFunction reduces the set of matched elements to those that pass the function's test.
+// It returns a new Selection object for this subset of elements.
+func (s *Selection) FilterFunction(f func(int, *Selection) bool) *Selection {
+	return pushStack(s, winnowFunction(s, f, true))
+}
+
+// NotFunction removes elements from the Selection that pass the function's test.
+// It returns a new Selection object with the matching elements removed.
+func (s *Selection) NotFunction(f func(int, *Selection) bool) *Selection {
+	return pushStack(s, winnowFunction(s, f, false))
+}
+
+// FilterNodes reduces the set of matched elements to those that match the specified nodes.
+// It returns a new Selection object for this subset of elements.
+func (s *Selection) FilterNodes(nodes ...*html.Node) *Selection {
+	return pushStack(s, winnowNodes(s, nodes, true))
+}
+
+// NotNodes removes elements from the Selection that match the specified nodes.
+// It returns a new Selection object with the matching elements removed.
+func (s *Selection) NotNodes(nodes ...*html.Node) *Selection {
+	return pushStack(s, winnowNodes(s, nodes, false))
+}
+
+// FilterSelection reduces the set of matched elements to those that match a
+// node in the specified Selection object.
+// It returns a new Selection object for this subset of elements.
+func (s *Selection) FilterSelection(sel *Selection) *Selection {
+	if sel == nil {
+		return pushStack(s, winnowNodes(s, nil, true))
+	}
+	return pushStack(s, winnowNodes(s, sel.Nodes, true))
+}
+
+// NotSelection removes elements from the Selection that match a node in the specified
+// Selection object. It returns a new Selection object with the matching elements removed.
+func (s *Selection) NotSelection(sel *Selection) *Selection {
+	if sel == nil {
+		return pushStack(s, winnowNodes(s, nil, false))
+	}
+	return pushStack(s, winnowNodes(s, sel.Nodes, false))
+}
+
+// Intersection is an alias for FilterSelection.
+func (s *Selection) Intersection(sel *Selection) *Selection {
+	return s.FilterSelection(sel)
+}
+
+// Has reduces the set of matched elements to those that have a descendant
+// that matches the selector.
+// It returns a new Selection object with the matching elements.
+func (s *Selection) Has(selector string) *Selection {
+	return s.HasSelection(s.document.Find(selector))
+}
+
+// HasMatcher reduces the set of matched elements to those that have a descendant
+// that matches the matcher.
+// It returns a new Selection object with the matching elements.
+func (s *Selection) HasMatcher(m Matcher) *Selection {
+	return s.HasSelection(s.document.FindMatcher(m))
+}
+
+// HasNodes reduces the set of matched elements to those that have a
+// descendant that matches one of the nodes.
+// It returns a new Selection object with the matching elements.
+func (s *Selection) HasNodes(nodes ...*html.Node) *Selection {
+	return s.FilterFunction(func(_ int, sel *Selection) bool {
+		// Add all nodes that contain one of the specified nodes
+		for _, n := range nodes {
+			if sel.Contains(n) {
+				return true
+			}
+		}
+		return false
+	})
+}
+
+// HasSelection reduces the set of matched elements to those that have a
+// descendant that matches one of the nodes of the specified Selection object.
+// It returns a new Selection object with the matching elements.
+func (s *Selection) HasSelection(sel *Selection) *Selection {
+	if sel == nil {
+		return s.HasNodes()
+	}
+	return s.HasNodes(sel.Nodes...)
+}
+
+// End ends the most recent filtering operation in the current chain and
+// returns the set of matched elements to its previous state.
+func (s *Selection) End() *Selection {
+	if s.prevSel != nil {
+		return s.prevSel
+	}
+	return newEmptySelection(s.document)
+}
+
+// Filter based on the matcher, and the indicator to keep (Filter) or
+// to get rid of (Not) the matching elements.
+func winnow(sel *Selection, m Matcher, keep bool) []*html.Node {
+	// Optimize if keep is requested
+	if keep {
+		return m.Filter(sel.Nodes)
+	}
+	// Use grep
+	return grep(sel, func(i int, s *Selection) bool {
+		return !m.Match(s.Get(0))
+	})
+}
+
+// Filter based on an array of nodes, and the indicator to keep (Filter) or
+// to get rid of (Not) the matching elements.
+func winnowNodes(sel *Selection, nodes []*html.Node, keep bool) []*html.Node {
+	if len(nodes)+len(sel.Nodes) < minNodesForSet {
+		return grep(sel, func(i int, s *Selection) bool {
+			return isInSlice(nodes, s.Get(0)) == keep
+		})
+	}
+
+	set := make(map[*html.Node]bool)
+	for _, n := range nodes {
+		set[n] = true
+	}
+	return grep(sel, func(i int, s *Selection) bool {
+		return set[s.Get(0)] == keep
+	})
+}
+
+// Filter based on a function test, and the indicator to keep (Filter) or
+// to get rid of (Not) the matching elements.
+func winnowFunction(sel *Selection, f func(int, *Selection) bool, keep bool) []*html.Node {
+	return grep(sel, func(i int, s *Selection) bool {
+		return f(i, s) == keep
+	})
+}

vendor/github.com/PuerkitoBio/goquery/go.mod

@@ -0,0 +1,8 @@
+module github.com/PuerkitoBio/goquery
+
+require (
+	github.com/andybalholm/cascadia v1.1.0
+	golang.org/x/net v0.0.0-20200202094626-16171245cfb2
+)
+
+go 1.13

vendor/github.com/PuerkitoBio/goquery/go.sum

@@ -0,0 +1,8 @@
+github.com/andybalholm/cascadia v1.1.0 h1:BuuO6sSfQNFRu1LppgbD25Hr2vLYW25JvxHs5zzsLTo=
+github.com/andybalholm/cascadia v1.1.0/go.mod h1:GsXiBklL0woXo1j/WYWtSYYC4ouU9PqHO0sqidkEA4Y=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/net v0.0.0-20180218175443-cbe0f9307d01/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20200202094626-16171245cfb2 h1:CCH4IOTTfewWjGOlSp+zGcjutRKlBEZQ6wTn8ozI/nI=
+golang.org/x/net v0.0.0-20200202094626-16171245cfb2/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

vendor/github.com/PuerkitoBio/goquery/iteration.go

@@ -0,0 +1,39 @@
+package goquery
+
+// Each iterates over a Selection object, executing a function for each
+// matched element. It returns the current Selection object. The function
+// f is called for each element in the selection with the index of the
+// element in that selection starting at 0, and a *Selection that contains
+// only that element.
+func (s *Selection) Each(f func(int, *Selection)) *Selection {
+	for i, n := range s.Nodes {
+		f(i, newSingleSelection(n, s.document))
+	}
+	return s
+}
+
+// EachWithBreak iterates over a Selection object, executing a function for each
+// matched element. It is identical to Each except that it is possible to break
+// out of the loop by returning false in the callback function. It returns the
+// current Selection object.
+func (s *Selection) EachWithBreak(f func(int, *Selection) bool) *Selection {
+	for i, n := range s.Nodes {
+		if !f(i, newSingleSelection(n, s.document)) {
+			return s
+		}
+	}
+	return s
+}
+
+// Map passes each element in the current matched set through a function,
+// producing a slice of string holding the returned values. The function
+// f is called for each element in the selection with the index of the
+// element in that selection starting at 0, and a *Selection that contains
+// only that element.
+func (s *Selection) Map(f func(int, *Selection) string) (result []string) {
+	for i, n := range s.Nodes {
+		result = append(result, f(i, newSingleSelection(n, s.document)))
+	}
+
+	return result
+}

vendor/github.com/PuerkitoBio/goquery/manipulation.go

@@ -0,0 +1,679 @@
+package goquery
+
+import (
+	"strings"
+
+	"golang.org/x/net/html"
+)
+
+// After applies the selector from the root document and inserts the matched elements
+// after the elements in the set of matched elements.
+//
+// If one of the matched elements in the selection is not currently in the
+// document, it's impossible to insert nodes after it, so it will be ignored.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) After(selector string) *Selection {
+	return s.AfterMatcher(compileMatcher(selector))
+}
+
+// AfterMatcher applies the matcher from the root document and inserts the matched elements
+// after the elements in the set of matched elements.
+//
+// If one of the matched elements in the selection is not currently in the
+// document, it's impossible to insert nodes after it, so it will be ignored.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) AfterMatcher(m Matcher) *Selection {
+	return s.AfterNodes(m.MatchAll(s.document.rootNode)...)
+}
+
+// AfterSelection inserts the elements in the selection after each element in the set of matched
+// elements.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) AfterSelection(sel *Selection) *Selection {
+	return s.AfterNodes(sel.Nodes...)
+}
+
+// AfterHtml parses the html and inserts it after the set of matched elements.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) AfterHtml(htmlStr string) *Selection {
+	return s.eachNodeHtml(htmlStr, true, func(node *html.Node, nodes []*html.Node) {
+		nextSibling := node.NextSibling
+		for _, n := range nodes {
+			if node.Parent != nil {
+				node.Parent.InsertBefore(n, nextSibling)
+			}
+		}
+	})
+}
+
+// AfterNodes inserts the nodes after each element in the set of matched elements.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) AfterNodes(ns ...*html.Node) *Selection {
+	return s.manipulateNodes(ns, true, func(sn *html.Node, n *html.Node) {
+		if sn.Parent != nil {
+			sn.Parent.InsertBefore(n, sn.NextSibling)
+		}
+	})
+}
+
+// Append appends the elements specified by the selector to the end of each element
+// in the set of matched elements, following those rules:
+//
+// 1) The selector is applied to the root document.
+//
+// 2) Elements that are part of the document will be moved to the new location.
+//
+// 3) If there are multiple locations to append to, cloned nodes will be
+// appended to all target locations except the last one, which will be moved
+// as noted in (2).
+func (s *Selection) Append(selector string) *Selection {
+	return s.AppendMatcher(compileMatcher(selector))
+}
+
+// AppendMatcher appends the elements specified by the matcher to the end of each element
+// in the set of matched elements.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) AppendMatcher(m Matcher) *Selection {
+	return s.AppendNodes(m.MatchAll(s.document.rootNode)...)
+}
+
+// AppendSelection appends the elements in the selection to the end of each element
+// in the set of matched elements.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) AppendSelection(sel *Selection) *Selection {
+	return s.AppendNodes(sel.Nodes...)
+}
+
+// AppendHtml parses the html and appends it to the set of matched elements.
+func (s *Selection) AppendHtml(htmlStr string) *Selection {
+	return s.eachNodeHtml(htmlStr, false, func(node *html.Node, nodes []*html.Node) {
+		for _, n := range nodes {
+			node.AppendChild(n)
+		}
+	})
+}
+
+// AppendNodes appends the specified nodes to each node in the set of matched elements.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) AppendNodes(ns ...*html.Node) *Selection {
+	return s.manipulateNodes(ns, false, func(sn *html.Node, n *html.Node) {
+		sn.AppendChild(n)
+	})
+}
+
+// Before inserts the matched elements before each element in the set of matched elements.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) Before(selector string) *Selection {
+	return s.BeforeMatcher(compileMatcher(selector))
+}
+
+// BeforeMatcher inserts the matched elements before each element in the set of matched elements.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) BeforeMatcher(m Matcher) *Selection {
+	return s.BeforeNodes(m.MatchAll(s.document.rootNode)...)
+}
+
+// BeforeSelection inserts the elements in the selection before each element in the set of matched
+// elements.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) BeforeSelection(sel *Selection) *Selection {
+	return s.BeforeNodes(sel.Nodes...)
+}
+
+// BeforeHtml parses the html and inserts it before the set of matched elements.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) BeforeHtml(htmlStr string) *Selection {
+	return s.eachNodeHtml(htmlStr, true, func(node *html.Node, nodes []*html.Node) {
+		for _, n := range nodes {
+			if node.Parent != nil {
+				node.Parent.InsertBefore(n, node)
+			}
+		}
+	})
+}
+
+// BeforeNodes inserts the nodes before each element in the set of matched elements.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) BeforeNodes(ns ...*html.Node) *Selection {
+	return s.manipulateNodes(ns, false, func(sn *html.Node, n *html.Node) {
+		if sn.Parent != nil {
+			sn.Parent.InsertBefore(n, sn)
+		}
+	})
+}
+
+// Clone creates a deep copy of the set of matched nodes. The new nodes will not be
+// attached to the document.
+func (s *Selection) Clone() *Selection {
+	ns := newEmptySelection(s.document)
+	ns.Nodes = cloneNodes(s.Nodes)
+	return ns
+}
+
+// Empty removes all children nodes from the set of matched elements.
+// It returns the children nodes in a new Selection.
+func (s *Selection) Empty() *Selection {
+	var nodes []*html.Node
+
+	for _, n := range s.Nodes {
+		for c := n.FirstChild; c != nil; c = n.FirstChild {
+			n.RemoveChild(c)
+			nodes = append(nodes, c)
+		}
+	}
+
+	return pushStack(s, nodes)
+}
+
+// Prepend prepends the elements specified by the selector to each element in
+// the set of matched elements, following the same rules as Append.
+func (s *Selection) Prepend(selector string) *Selection {
+	return s.PrependMatcher(compileMatcher(selector))
+}
+
+// PrependMatcher prepends the elements specified by the matcher to each
+// element in the set of matched elements.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) PrependMatcher(m Matcher) *Selection {
+	return s.PrependNodes(m.MatchAll(s.document.rootNode)...)
+}
+
+// PrependSelection prepends the elements in the selection to each element in
+// the set of matched elements.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) PrependSelection(sel *Selection) *Selection {
+	return s.PrependNodes(sel.Nodes...)
+}
+
+// PrependHtml parses the html and prepends it to the set of matched elements.
+func (s *Selection) PrependHtml(htmlStr string) *Selection {
+	return s.eachNodeHtml(htmlStr, false, func(node *html.Node, nodes []*html.Node) {
+		firstChild := node.FirstChild
+		for _, n := range nodes {
+			node.InsertBefore(n, firstChild)
+		}
+	})
+}
+
+// PrependNodes prepends the specified nodes to each node in the set of
+// matched elements.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) PrependNodes(ns ...*html.Node) *Selection {
+	return s.manipulateNodes(ns, true, func(sn *html.Node, n *html.Node) {
+		// sn.FirstChild may be nil, in which case this functions like
+		// sn.AppendChild()
+		sn.InsertBefore(n, sn.FirstChild)
+	})
+}
+
+// Remove removes the set of matched elements from the document.
+// It returns the same selection, now consisting of nodes not in the document.
+func (s *Selection) Remove() *Selection {
+	for _, n := range s.Nodes {
+		if n.Parent != nil {
+			n.Parent.RemoveChild(n)
+		}
+	}
+
+	return s
+}
+
+// RemoveFiltered removes from the current set of matched elements those that
+// match the selector filter. It returns the Selection of removed nodes.
+//
+// For example if the selection s contains "<h1>", "<h2>" and "<h3>"
+// and s.RemoveFiltered("h2") is called, only the "<h2>" node is removed
+// (and returned), while "<h1>" and "<h3>" are kept in the document.
+func (s *Selection) RemoveFiltered(selector string) *Selection {
+	return s.RemoveMatcher(compileMatcher(selector))
+}
+
+// RemoveMatcher removes from the current set of matched elements those that
+// match the Matcher filter. It returns the Selection of removed nodes.
+// See RemoveFiltered for additional information.
+func (s *Selection) RemoveMatcher(m Matcher) *Selection {
+	return s.FilterMatcher(m).Remove()
+}
+
+// ReplaceWith replaces each element in the set of matched elements with the
+// nodes matched by the given selector.
+// It returns the removed elements.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) ReplaceWith(selector string) *Selection {
+	return s.ReplaceWithMatcher(compileMatcher(selector))
+}
+
+// ReplaceWithMatcher replaces each element in the set of matched elements with
+// the nodes matched by the given Matcher.
+// It returns the removed elements.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) ReplaceWithMatcher(m Matcher) *Selection {
+	return s.ReplaceWithNodes(m.MatchAll(s.document.rootNode)...)
+}
+
+// ReplaceWithSelection replaces each element in the set of matched elements with
+// the nodes from the given Selection.
+// It returns the removed elements.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) ReplaceWithSelection(sel *Selection) *Selection {
+	return s.ReplaceWithNodes(sel.Nodes...)
+}
+
+// ReplaceWithHtml replaces each element in the set of matched elements with
+// the parsed HTML.
+// It returns the removed elements.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) ReplaceWithHtml(htmlStr string) *Selection {
+	s.eachNodeHtml(htmlStr, true, func(node *html.Node, nodes []*html.Node) {
+		nextSibling := node.NextSibling
+		for _, n := range nodes {
+			if node.Parent != nil {
+				node.Parent.InsertBefore(n, nextSibling)
+			}
+		}
+	})
+	return s.Remove()
+}
+
+// ReplaceWithNodes replaces each element in the set of matched elements with
+// the given nodes.
+// It returns the removed elements.
+//
+// This follows the same rules as Selection.Append.
+func (s *Selection) ReplaceWithNodes(ns ...*html.Node) *Selection {
+	s.AfterNodes(ns...)
+	return s.Remove()
+}
+
+// SetHtml sets the html content of each element in the selection to
+// specified html string.
+func (s *Selection) SetHtml(htmlStr string) *Selection {
+	for _, context := range s.Nodes {
+		for c := context.FirstChild; c != nil; c = context.FirstChild {
+			context.RemoveChild(c)
+		}
+	}
+	return s.eachNodeHtml(htmlStr, false, func(node *html.Node, nodes []*html.Node) {
+		for _, n := range nodes {
+			node.AppendChild(n)
+		}
+	})
+}
+
+// SetText sets the content of each element in the selection to specified content.
+// The provided text string is escaped.
+func (s *Selection) SetText(text string) *Selection {
+	return s.SetHtml(html.EscapeString(text))
+}
+
+// Unwrap removes the parents of the set of matched elements, leaving the matched
+// elements (and their siblings, if any) in their place.
+// It returns the original selection.
+func (s *Selection) Unwrap() *Selection {
+	s.Parent().Each(func(i int, ss *Selection) {
+		// For some reason, jquery allows unwrap to remove the <head> element, so
+		// allowing it here too. Same for <html>. Why it allows those elements to
+		// be unwrapped while not allowing body is a mystery to me.
+		if ss.Nodes[0].Data != "body" {
+			ss.ReplaceWithSelection(ss.Contents())
+		}
+	})
+
+	return s
+}
+
+// Wrap wraps each element in the set of matched elements inside the first
+// element matched by the given selector. The matched child is cloned before
+// being inserted into the document.
+//
+// It returns the original set of elements.
+func (s *Selection) Wrap(selector string) *Selection {
+	return s.WrapMatcher(compileMatcher(selector))
+}
+
+// WrapMatcher wraps each element in the set of matched elements inside the
+// first element matched by the given matcher. The matched child is cloned
+// before being inserted into the document.
+//
+// It returns the original set of elements.
+func (s *Selection) WrapMatcher(m Matcher) *Selection {
+	return s.wrapNodes(m.MatchAll(s.document.rootNode)...)
+}
+
+// WrapSelection wraps each element in the set of matched elements inside the
+// first element in the given Selection. The element is cloned before being
+// inserted into the document.
+//
+// It returns the original set of elements.
+func (s *Selection) WrapSelection(sel *Selection) *Selection {
+	return s.wrapNodes(sel.Nodes...)
+}
+
+// WrapHtml wraps each element in the set of matched elements inside the inner-
+// most child of the given HTML.
+//
+// It returns the original set of elements.
+func (s *Selection) WrapHtml(htmlStr string) *Selection {
+	nodesMap := make(map[string][]*html.Node)
+	for _, context := range s.Nodes {
+		var parent *html.Node
+		if context.Parent != nil {
+			parent = context.Parent
+		} else {
+			parent = &html.Node{Type: html.ElementNode}
+		}
+		nodes, found := nodesMap[nodeName(parent)]
+		if !found {
+			nodes = parseHtmlWithContext(htmlStr, parent)
+			nodesMap[nodeName(parent)] = nodes
+		}
+		newSingleSelection(context, s.document).wrapAllNodes(cloneNodes(nodes)...)
+	}
+	return s
+}
+
+// WrapNode wraps each element in the set of matched elements inside the inner-
+// most child of the given node. The given node is copied before being inserted
+// into the document.
+//
+// It returns the original set of elements.
+func (s *Selection) WrapNode(n *html.Node) *Selection {
+	return s.wrapNodes(n)
+}
+
+func (s *Selection) wrapNodes(ns ...*html.Node) *Selection {
+	s.Each(func(i int, ss *Selection) {
+		ss.wrapAllNodes(ns...)
+	})
+
+	return s
+}
+
+// WrapAll wraps a single HTML structure, matched by the given selector, around
+// all elements in the set of matched elements. The matched child is cloned
+// before being inserted into the document.
+//
+// It returns the original set of elements.
+func (s *Selection) WrapAll(selector string) *Selection {
+	return s.WrapAllMatcher(compileMatcher(selector))
+}
+
+// WrapAllMatcher wraps a single HTML structure, matched by the given Matcher,
+// around all elements in the set of matched elements. The matched child is
+// cloned before being inserted into the document.
+//
+// It returns the original set of elements.
+func (s *Selection) WrapAllMatcher(m Matcher) *Selection {
+	return s.wrapAllNodes(m.MatchAll(s.document.rootNode)...)
+}
+
+// WrapAllSelection wraps a single HTML structure, the first node of the given
+// Selection, around all elements in the set of matched elements. The matched
+// child is cloned before being inserted into the document.
+//
+// It returns the original set of elements.
+func (s *Selection) WrapAllSelection(sel *Selection) *Selection {
+	return s.wrapAllNodes(sel.Nodes...)
+}
+
+// WrapAllHtml wraps the given HTML structure around all elements in the set of
+// matched elements. The matched child is cloned before being inserted into the
+// document.
+//
+// It returns the original set of elements.
+func (s *Selection) WrapAllHtml(htmlStr string) *Selection {
+	var context *html.Node
+	var nodes []*html.Node
+	if len(s.Nodes) > 0 {
+		context = s.Nodes[0]
+		if context.Parent != nil {
+			nodes = parseHtmlWithContext(htmlStr, context)
+		} else {
+			nodes = parseHtml(htmlStr)
+		}
+	}
+	return s.wrapAllNodes(nodes...)
+}
+
+func (s *Selection) wrapAllNodes(ns ...*html.Node) *Selection {
+	if len(ns) > 0 {
+		return s.WrapAllNode(ns[0])
+	}
+	return s
+}
+
+// WrapAllNode wraps the given node around the first element in the Selection,
+// making all other nodes in the Selection children of the given node. The node
+// is cloned before being inserted into the document.
+//
+// It returns the original set of elements.
+func (s *Selection) WrapAllNode(n *html.Node) *Selection {
+	if s.Size() == 0 {
+		return s
+	}
+
+	wrap := cloneNode(n)
+
+	first := s.Nodes[0]
+	if first.Parent != nil {
+		first.Parent.InsertBefore(wrap, first)
+		first.Parent.RemoveChild(first)
+	}
+
+	for c := getFirstChildEl(wrap); c != nil; c = getFirstChildEl(wrap) {
+		wrap = c
+	}
+
+	newSingleSelection(wrap, s.document).AppendSelection(s)
+
+	return s
+}
+
+// WrapInner wraps an HTML structure, matched by the given selector, around the
+// content of element in the set of matched elements. The matched child is
+// cloned before being inserted into the document.
+//
+// It returns the original set of elements.
+func (s *Selection) WrapInner(selector string) *Selection {
+	return s.WrapInnerMatcher(compileMatcher(selector))
+}
+
+// WrapInnerMatcher wraps an HTML structure, matched by the given selector,
+// around the content of element in the set of matched elements. The matched
+// child is cloned before being inserted into the document.
+//
+// It returns the original set of elements.
+func (s *Selection) WrapInnerMatcher(m Matcher) *Selection {
+	return s.wrapInnerNodes(m.MatchAll(s.document.rootNode)...)
+}
+
+// WrapInnerSelection wraps an HTML structure, matched by the given selector,
+// around the content of element in the set of matched elements. The matched
+// child is cloned before being inserted into the document.
+//
+// It returns the original set of elements.
+func (s *Selection) WrapInnerSelection(sel *Selection) *Selection {
+	return s.wrapInnerNodes(sel.Nodes...)
+}
+
+// WrapInnerHtml wraps an HTML structure, matched by the given selector, around
+// the content of element in the set of matched elements. The matched child is
+// cloned before being inserted into the document.
+//
+// It returns the original set of elements.
+func (s *Selection) WrapInnerHtml(htmlStr string) *Selection {
+	nodesMap := make(map[string][]*html.Node)
+	for _, context := range s.Nodes {
+		nodes, found := nodesMap[nodeName(context)]
+		if !found {
+			nodes = parseHtmlWithContext(htmlStr, context)
+			nodesMap[nodeName(context)] = nodes
+		}
+		newSingleSelection(context, s.document).wrapInnerNodes(cloneNodes(nodes)...)
+	}
+	return s
+}
+
+// WrapInnerNode wraps an HTML structure, matched by the given selector, around
+// the content of element in the set of matched elements. The matched child is
+// cloned before being inserted into the document.
+//
+// It returns the original set of elements.
+func (s *Selection) WrapInnerNode(n *html.Node) *Selection {
+	return s.wrapInnerNodes(n)
+}
+
+func (s *Selection) wrapInnerNodes(ns ...*html.Node) *Selection {
+	if len(ns) == 0 {
+		return s
+	}
+
+	s.Each(func(i int, s *Selection) {
+		contents := s.Contents()
+
+		if contents.Size() > 0 {
+			contents.wrapAllNodes(ns...)
+		} else {
+			s.AppendNodes(cloneNode(ns[0]))
+		}
+	})
+
+	return s
+}
+
+func parseHtml(h string) []*html.Node {
+	// Errors are only returned when the io.Reader returns any error besides
+	// EOF, but strings.Reader never will
+	nodes, err := html.ParseFragment(strings.NewReader(h), &html.Node{Type: html.ElementNode})
+	if err != nil {
+		panic("goquery: failed to parse HTML: " + err.Error())
+	}
+	return nodes
+}
+
+func parseHtmlWithContext(h string, context *html.Node) []*html.Node {
+	// Errors are only returned when the io.Reader returns any error besides
+	// EOF, but strings.Reader never will
+	nodes, err := html.ParseFragment(strings.NewReader(h), context)
+	if err != nil {
+		panic("goquery: failed to parse HTML: " + err.Error())
+	}
+	return nodes
+}
+
+// Get the first child that is an ElementNode
+func getFirstChildEl(n *html.Node) *html.Node {
+	c := n.FirstChild
+	for c != nil && c.Type != html.ElementNode {
+		c = c.NextSibling
+	}
+	return c
+}
+
+// Deep copy a slice of nodes.
+func cloneNodes(ns []*html.Node) []*html.Node {
+	cns := make([]*html.Node, 0, len(ns))
+
+	for _, n := range ns {
+		cns = append(cns, cloneNode(n))
+	}
+
+	return cns
+}
+
+// Deep copy a node. The new node has clones of all the original node's
+// children but none of its parents or siblings.
+func cloneNode(n *html.Node) *html.Node {
+	nn := &html.Node{
+		Type:     n.Type,
+		DataAtom: n.DataAtom,
+		Data:     n.Data,
+		Attr:     make([]html.Attribute, len(n.Attr)),
+	}
+
+	copy(nn.Attr, n.Attr)
+	for c := n.FirstChild; c != nil; c = c.NextSibling {
+		nn.AppendChild(cloneNode(c))
+	}
+
+	return nn
+}
+
+func (s *Selection) manipulateNodes(ns []*html.Node, reverse bool,
+	f func(sn *html.Node, n *html.Node)) *Selection {
+
+	lasti := s.Size() - 1
+
+	// net.Html doesn't provide document fragments for insertion, so to get
+	// things in the correct order with After() and Prepend(), the callback
+	// needs to be called on the reverse of the nodes.
+	if reverse {
+		for i, j := 0, len(ns)-1; i < j; i, j = i+1, j-1 {
+			ns[i], ns[j] = ns[j], ns[i]
+		}
+	}
+
+	for i, sn := range s.Nodes {
+		for _, n := range ns {
+			if i != lasti {
+				f(sn, cloneNode(n))
+			} else {
+				if n.Parent != nil {
+					n.Parent.RemoveChild(n)
+				}
+				f(sn, n)
+			}
+		}
+	}
+
+	return s
+}
+
+// eachNodeHtml parses the given html string and inserts the resulting nodes in the dom with the mergeFn.
+// The parsed nodes are inserted for each element of the selection.
+// isParent can be used to indicate that the elements of the selection should be treated as the parent for the parsed html.
+// A cache is used to avoid parsing the html multiple times should the elements of the selection result in the same context.
+func (s *Selection) eachNodeHtml(htmlStr string, isParent bool, mergeFn func(n *html.Node, nodes []*html.Node)) *Selection {
+	// cache to avoid parsing the html for the same context multiple times
+	nodeCache := make(map[string][]*html.Node)
+	var context *html.Node
+	for _, n := range s.Nodes {
+		if isParent {
+			context = n.Parent
+		} else {
+			if n.Type != html.ElementNode {
+				continue
+			}
+			context = n
+		}
+		if context != nil {
+			nodes, found := nodeCache[nodeName(context)]
+			if !found {
+				nodes = parseHtmlWithContext(htmlStr, context)
+				nodeCache[nodeName(context)] = nodes
+			}
+			mergeFn(n, cloneNodes(nodes))
+		}
+	}
+	return s
+}

vendor/github.com/PuerkitoBio/goquery/property.go

@@ -0,0 +1,275 @@
+package goquery
+
+import (
+	"bytes"
+	"regexp"
+	"strings"
+
+	"golang.org/x/net/html"
+)
+
+var rxClassTrim = regexp.MustCompile("[\t\r\n]")
+
+// Attr gets the specified attribute's value for the first element in the
+// Selection. To get the value for each element individually, use a looping
+// construct such as Each or Map method.
+func (s *Selection) Attr(attrName string) (val string, exists bool) {
+	if len(s.Nodes) == 0 {
+		return
+	}
+	return getAttributeValue(attrName, s.Nodes[0])
+}
+
+// AttrOr works like Attr but returns default value if attribute is not present.
+func (s *Selection) AttrOr(attrName, defaultValue string) string {
+	if len(s.Nodes) == 0 {
+		return defaultValue
+	}
+
+	val, exists := getAttributeValue(attrName, s.Nodes[0])
+	if !exists {
+		return defaultValue
+	}
+
+	return val
+}
+
+// RemoveAttr removes the named attribute from each element in the set of matched elements.
+func (s *Selection) RemoveAttr(attrName string) *Selection {
+	for _, n := range s.Nodes {
+		removeAttr(n, attrName)
+	}
+
+	return s
+}
+
+// SetAttr sets the given attribute on each element in the set of matched elements.
+func (s *Selection) SetAttr(attrName, val string) *Selection {
+	for _, n := range s.Nodes {
+		attr := getAttributePtr(attrName, n)
+		if attr == nil {
+			n.Attr = append(n.Attr, html.Attribute{Key: attrName, Val: val})
+		} else {
+			attr.Val = val
+		}
+	}
+
+	return s
+}
+
+// Text gets the combined text contents of each element in the set of matched
+// elements, including their descendants.
+func (s *Selection) Text() string {
+	var buf bytes.Buffer
+
+	// Slightly optimized vs calling Each: no single selection object created
+	var f func(*html.Node)
+	f = func(n *html.Node) {
+		if n.Type == html.TextNode {
+			// Keep newlines and spaces, like jQuery
+			buf.WriteString(n.Data)
+		}
+		if n.FirstChild != nil {
+			for c := n.FirstChild; c != nil; c = c.NextSibling {
+				f(c)
+			}
+		}
+	}
+	for _, n := range s.Nodes {
+		f(n)
+	}
+
+	return buf.String()
+}
+
+// Size is an alias for Length.
+func (s *Selection) Size() int {
+	return s.Length()
+}
+
+// Length returns the number of elements in the Selection object.
+func (s *Selection) Length() int {
+	return len(s.Nodes)
+}
+
+// Html gets the HTML contents of the first element in the set of matched
+// elements. It includes text and comment nodes.
+func (s *Selection) Html() (ret string, e error) {
+	// Since there is no .innerHtml, the HTML content must be re-created from
+	// the nodes using html.Render.
+	var buf bytes.Buffer
+
+	if len(s.Nodes) > 0 {
+		for c := s.Nodes[0].FirstChild; c != nil; c = c.NextSibling {
+			e = html.Render(&buf, c)
+			if e != nil {
+				return
+			}
+		}
+		ret = buf.String()
+	}
+
+	return
+}
+
+// AddClass adds the given class(es) to each element in the set of matched elements.
+// Multiple class names can be specified, separated by a space or via multiple arguments.
+func (s *Selection) AddClass(class ...string) *Selection {
+	classStr := strings.TrimSpace(strings.Join(class, " "))
+
+	if classStr == "" {
+		return s
+	}
+
+	tcls := getClassesSlice(classStr)
+	for _, n := range s.Nodes {
+		curClasses, attr := getClassesAndAttr(n, true)
+		for _, newClass := range tcls {
+			if !strings.Contains(curClasses, " "+newClass+" ") {
+				curClasses += newClass + " "
+			}
+		}
+
+		setClasses(n, attr, curClasses)
+	}
+
+	return s
+}
+
+// HasClass determines whether any of the matched elements are assigned the
+// given class.
+func (s *Selection) HasClass(class string) bool {
+	class = " " + class + " "
+	for _, n := range s.Nodes {
+		classes, _ := getClassesAndAttr(n, false)
+		if strings.Contains(classes, class) {
+			return true
+		}
+	}
+	return false
+}
+
+// RemoveClass removes the given class(es) from each element in the set of matched elements.
+// Multiple class names can be specified, separated by a space or via multiple arguments.
+// If no class name is provided, all classes are removed.
+func (s *Selection) RemoveClass(class ...string) *Selection {
+	var rclasses []string
+
+	classStr := strings.TrimSpace(strings.Join(class, " "))
+	remove := classStr == ""
+
+	if !remove {
+		rclasses = getClassesSlice(classStr)
+	}
+
+	for _, n := range s.Nodes {
+		if remove {
+			removeAttr(n, "class")
+		} else {
+			classes, attr := getClassesAndAttr(n, true)
+			for _, rcl := range rclasses {
+				classes = strings.Replace(classes, " "+rcl+" ", " ", -1)
+			}
+
+			setClasses(n, attr, classes)
+		}
+	}
+
+	return s
+}
+
+// ToggleClass adds or removes the given class(es) for each element in the set of matched elements.
+// Multiple class names can be specified, separated by a space or via multiple arguments.
+func (s *Selection) ToggleClass(class ...string) *Selection {
+	classStr := strings.TrimSpace(strings.Join(class, " "))
+
+	if classStr == "" {
+		return s
+	}
+
+	tcls := getClassesSlice(classStr)
+
+	for _, n := range s.Nodes {
+		classes, attr := getClassesAndAttr(n, true)
+		for _, tcl := range tcls {
+			if strings.Contains(classes, " "+tcl+" ") {
+				classes = strings.Replace(classes, " "+tcl+" ", " ", -1)
+			} else {
+				classes += tcl + " "
+			}
+		}
+
+		setClasses(n, attr, classes)
+	}
+
+	return s
+}
+
+func getAttributePtr(attrName string, n *html.Node) *html.Attribute {
+	if n == nil {
+		return nil
+	}
+
+	for i, a := range n.Attr {
+		if a.Key == attrName {
+			return &n.Attr[i]
+		}
+	}
+	return nil
+}
+
+// Private function to get the specified attribute's value from a node.
+func getAttributeValue(attrName string, n *html.Node) (val string, exists bool) {
+	if a := getAttributePtr(attrName, n); a != nil {
+		val = a.Val
+		exists = true
+	}
+	return
+}
+
+// Get and normalize the "class" attribute from the node.
+func getClassesAndAttr(n *html.Node, create bool) (classes string, attr *html.Attribute) {
+	// Applies only to element nodes
+	if n.Type == html.ElementNode {
+		attr = getAttributePtr("class", n)
+		if attr == nil && create {
+			n.Attr = append(n.Attr, html.Attribute{
+				Key: "class",
+				Val: "",
+			})
+			attr = &n.Attr[len(n.Attr)-1]
+		}
+	}
+
+	if attr == nil {
+		classes = " "
+	} else {
+		classes = rxClassTrim.ReplaceAllString(" "+attr.Val+" ", " ")
+	}
+
+	return
+}
+
+func getClassesSlice(classes string) []string {
+	return strings.Split(rxClassTrim.ReplaceAllString(" "+classes+" ", " "), " ")
+}
+
+func removeAttr(n *html.Node, attrName string) {
+	for i, a := range n.Attr {
+		if a.Key == attrName {
+			n.Attr[i], n.Attr[len(n.Attr)-1], n.Attr =
+				n.Attr[len(n.Attr)-1], html.Attribute{}, n.Attr[:len(n.Attr)-1]
+			return
+		}
+	}
+}
+
+func setClasses(n *html.Node, attr *html.Attribute, classes string) {
+	classes = strings.TrimSpace(classes)
+	if classes == "" {
+		removeAttr(n, "class")
+		return
+	}
+
+	attr.Val = classes
+}

vendor/github.com/PuerkitoBio/goquery/query.go

@@ -0,0 +1,49 @@
+package goquery
+
+import "golang.org/x/net/html"
+
+// Is checks the current matched set of elements against a selector and
+// returns true if at least one of these elements matches.
+func (s *Selection) Is(selector string) bool {
+	return s.IsMatcher(compileMatcher(selector))
+}
+
+// IsMatcher checks the current matched set of elements against a matcher and
+// returns true if at least one of these elements matches.
+func (s *Selection) IsMatcher(m Matcher) bool {
+	if len(s.Nodes) > 0 {
+		if len(s.Nodes) == 1 {
+			return m.Match(s.Nodes[0])
+		}
+		return len(m.Filter(s.Nodes)) > 0
+	}
+
+	return false
+}
+
+// IsFunction checks the current matched set of elements against a predicate and
+// returns true if at least one of these elements matches.
+func (s *Selection) IsFunction(f func(int, *Selection) bool) bool {
+	return s.FilterFunction(f).Length() > 0
+}
+
+// IsSelection checks the current matched set of elements against a Selection object
+// and returns true if at least one of these elements matches.
+func (s *Selection) IsSelection(sel *Selection) bool {
+	return s.FilterSelection(sel).Length() > 0
+}
+
+// IsNodes checks the current matched set of elements against the specified nodes
+// and returns true if at least one of these elements matches.
+func (s *Selection) IsNodes(nodes ...*html.Node) bool {
+	return s.FilterNodes(nodes...).Length() > 0
+}
+
+// Contains returns true if the specified Node is within,
+// at any depth, one of the nodes in the Selection object.
+// It is NOT inclusive, to behave like jQuery's implementation, and
+// unlike Javascript's .contains, so if the contained
+// node is itself in the selection, it returns false.
+func (s *Selection) Contains(n *html.Node) bool {
+	return sliceContains(s.Nodes, n)
+}

vendor/github.com/PuerkitoBio/goquery/traversal.go

@@ -0,0 +1,698 @@
+package goquery
+
+import "golang.org/x/net/html"
+
+type siblingType int
+
+// Sibling type, used internally when iterating over children at the same
+// level (siblings) to specify which nodes are requested.
+const (
+	siblingPrevUntil siblingType = iota - 3
+	siblingPrevAll
+	siblingPrev
+	siblingAll
+	siblingNext
+	siblingNextAll
+	siblingNextUntil
+	siblingAllIncludingNonElements
+)
+
+// Find gets the descendants of each element in the current set of matched
+// elements, filtered by a selector. It returns a new Selection object
+// containing these matched elements.
+func (s *Selection) Find(selector string) *Selection {
+	return pushStack(s, findWithMatcher(s.Nodes, compileMatcher(selector)))
+}
+
+// FindMatcher gets the descendants of each element in the current set of matched
+// elements, filtered by the matcher. It returns a new Selection object
+// containing these matched elements.
+func (s *Selection) FindMatcher(m Matcher) *Selection {
+	return pushStack(s, findWithMatcher(s.Nodes, m))
+}
+
+// FindSelection gets the descendants of each element in the current
+// Selection, filtered by a Selection. It returns a new Selection object
+// containing these matched elements.
+func (s *Selection) FindSelection(sel *Selection) *Selection {
+	if sel == nil {
+		return pushStack(s, nil)
+	}
+	return s.FindNodes(sel.Nodes...)
+}
+
+// FindNodes gets the descendants of each element in the current
+// Selection, filtered by some nodes. It returns a new Selection object
+// containing these matched elements.
+func (s *Selection) FindNodes(nodes ...*html.Node) *Selection {
+	return pushStack(s, mapNodes(nodes, func(i int, n *html.Node) []*html.Node {
+		if sliceContains(s.Nodes, n) {
+			return []*html.Node{n}
+		}
+		return nil
+	}))
+}
+
+// Contents gets the children of each element in the Selection,
+// including text and comment nodes. It returns a new Selection object
+// containing these elements.
+func (s *Selection) Contents() *Selection {
+	return pushStack(s, getChildrenNodes(s.Nodes, siblingAllIncludingNonElements))
+}
+
+// ContentsFiltered gets the children of each element in the Selection,
+// filtered by the specified selector. It returns a new Selection
+// object containing these elements. Since selectors only act on Element nodes,
+// this function is an alias to ChildrenFiltered unless the selector is empty,
+// in which case it is an alias to Contents.
+func (s *Selection) ContentsFiltered(selector string) *Selection {
+	if selector != "" {
+		return s.ChildrenFiltered(selector)
+	}
+	return s.Contents()
+}
+
+// ContentsMatcher gets the children of each element in the Selection,
+// filtered by the specified matcher. It returns a new Selection
+// object containing these elements. Since matchers only act on Element nodes,
+// this function is an alias to ChildrenMatcher.
+func (s *Selection) ContentsMatcher(m Matcher) *Selection {
+	return s.ChildrenMatcher(m)
+}
+
+// Children gets the child elements of each element in the Selection.
+// It returns a new Selection object containing these elements.
+func (s *Selection) Children() *Selection {
+	return pushStack(s, getChildrenNodes(s.Nodes, siblingAll))
+}
+
+// ChildrenFiltered gets the child elements of each element in the Selection,
+// filtered by the specified selector. It returns a new
+// Selection object containing these elements.
+func (s *Selection) ChildrenFiltered(selector string) *Selection {
+	return filterAndPush(s, getChildrenNodes(s.Nodes, siblingAll), compileMatcher(selector))
+}
+
+// ChildrenMatcher gets the child elements of each element in the Selection,
+// filtered by the specified matcher. It returns a new
+// Selection object containing these elements.
+func (s *Selection) ChildrenMatcher(m Matcher) *Selection {
+	return filterAndPush(s, getChildrenNodes(s.Nodes, siblingAll), m)
+}
+
+// Parent gets the parent of each element in the Selection. It returns a
+// new Selection object containing the matched elements.
+func (s *Selection) Parent() *Selection {
+	return pushStack(s, getParentNodes(s.Nodes))
+}
+
+// ParentFiltered gets the parent of each element in the Selection filtered by a
+// selector. It returns a new Selection object containing the matched elements.
+func (s *Selection) ParentFiltered(selector string) *Selection {
+	return filterAndPush(s, getParentNodes(s.Nodes), compileMatcher(selector))
+}
+
+// ParentMatcher gets the parent of each element in the Selection filtered by a
+// matcher. It returns a new Selection object containing the matched elements.
+func (s *Selection) ParentMatcher(m Matcher) *Selection {
+	return filterAndPush(s, getParentNodes(s.Nodes), m)
+}
+
+// Closest gets the first element that matches the selector by testing the
+// element itself and traversing up through its ancestors in the DOM tree.
+func (s *Selection) Closest(selector string) *Selection {
+	cs := compileMatcher(selector)
+	return s.ClosestMatcher(cs)
+}
+
+// ClosestMatcher gets the first element that matches the matcher by testing the
+// element itself and traversing up through its ancestors in the DOM tree.
+func (s *Selection) ClosestMatcher(m Matcher) *Selection {
+	return pushStack(s, mapNodes(s.Nodes, func(i int, n *html.Node) []*html.Node {
+		// For each node in the selection, test the node itself, then each parent
+		// until a match is found.
+		for ; n != nil; n = n.Parent {
+			if m.Match(n) {
+				return []*html.Node{n}
+			}
+		}
+		return nil
+	}))
+}
+
+// ClosestNodes gets the first element that matches one of the nodes by testing the
+// element itself and traversing up through its ancestors in the DOM tree.
+func (s *Selection) ClosestNodes(nodes ...*html.Node) *Selection {
+	set := make(map[*html.Node]bool)
+	for _, n := range nodes {
+		set[n] = true
+	}
+	return pushStack(s, mapNodes(s.Nodes, func(i int, n *html.Node) []*html.Node {
+		// For each node in the selection, test the node itself, then each parent
+		// until a match is found.
+		for ; n != nil; n = n.Parent {
+			if set[n] {
+				return []*html.Node{n}
+			}
+		}
+		return nil
+	}))
+}
+
+// ClosestSelection gets the first element that matches one of the nodes in the
+// Selection by testing the element itself and traversing up through its ancestors
+// in the DOM tree.
+func (s *Selection) ClosestSelection(sel *Selection) *Selection {
+	if sel == nil {
+		return pushStack(s, nil)
+	}
+	return s.ClosestNodes(sel.Nodes...)
+}
+
+// Parents gets the ancestors of each element in the current Selection. It
+// returns a new Selection object with the matched elements.
+func (s *Selection) Parents() *Selection {
+	return pushStack(s, getParentsNodes(s.Nodes, nil, nil))
+}
+
+// ParentsFiltered gets the ancestors of each element in the current
+// Selection. It returns a new Selection object with the matched elements.
+func (s *Selection) ParentsFiltered(selector string) *Selection {
+	return filterAndPush(s, getParentsNodes(s.Nodes, nil, nil), compileMatcher(selector))
+}
+
+// ParentsMatcher gets the ancestors of each element in the current
+// Selection. It returns a new Selection object with the matched elements.
+func (s *Selection) ParentsMatcher(m Matcher) *Selection {
+	return filterAndPush(s, getParentsNodes(s.Nodes, nil, nil), m)
+}
+
+// ParentsUntil gets the ancestors of each element in the Selection, up to but
+// not including the element matched by the selector. It returns a new Selection
+// object containing the matched elements.
+func (s *Selection) ParentsUntil(selector string) *Selection {
+	return pushStack(s, getParentsNodes(s.Nodes, compileMatcher(selector), nil))
+}
+
+// ParentsUntilMatcher gets the ancestors of each element in the Selection, up to but
+// not including the element matched by the matcher. It returns a new Selection
+// object containing the matched elements.
+func (s *Selection) ParentsUntilMatcher(m Matcher) *Selection {
+	return pushStack(s, getParentsNodes(s.Nodes, m, nil))
+}
+
+// ParentsUntilSelection gets the ancestors of each element in the Selection,
+// up to but not including the elements in the specified Selection. It returns a
+// new Selection object containing the matched elements.
+func (s *Selection) ParentsUntilSelection(sel *Selection) *Selection {
+	if sel == nil {
+		return s.Parents()
+	}
+	return s.ParentsUntilNodes(sel.Nodes...)
+}
+
+// ParentsUntilNodes gets the ancestors of each element in the Selection,
+// up to but not including the specified nodes. It returns a
+// new Selection object containing the matched elements.
+func (s *Selection) ParentsUntilNodes(nodes ...*html.Node) *Selection {
+	return pushStack(s, getParentsNodes(s.Nodes, nil, nodes))
+}
+
+// ParentsFilteredUntil is like ParentsUntil, with the option to filter the
+// results based on a selector string. It returns a new Selection
+// object containing the matched elements.
+func (s *Selection) ParentsFilteredUntil(filterSelector, untilSelector string) *Selection {
+	return filterAndPush(s, getParentsNodes(s.Nodes, compileMatcher(untilSelector), nil), compileMatcher(filterSelector))
+}
+
+// ParentsFilteredUntilMatcher is like ParentsUntilMatcher, with the option to filter the
+// results based on a matcher. It returns a new Selection object containing the matched elements.
+func (s *Selection) ParentsFilteredUntilMatcher(filter, until Matcher) *Selection {
+	return filterAndPush(s, getParentsNodes(s.Nodes, until, nil), filter)
+}
+
+// ParentsFilteredUntilSelection is like ParentsUntilSelection, with the
+// option to filter the results based on a selector string. It returns a new
+// Selection object containing the matched elements.
+func (s *Selection) ParentsFilteredUntilSelection(filterSelector string, sel *Selection) *Selection {
+	return s.ParentsMatcherUntilSelection(compileMatcher(filterSelector), sel)
+}
+
+// ParentsMatcherUntilSelection is like ParentsUntilSelection, with the
+// option to filter the results based on a matcher. It returns a new
+// Selection object containing the matched elements.
+func (s *Selection) ParentsMatcherUntilSelection(filter Matcher, sel *Selection) *Selection {
+	if sel == nil {
+		return s.ParentsMatcher(filter)
+	}
+	return s.ParentsMatcherUntilNodes(filter, sel.Nodes...)
+}
+
+// ParentsFilteredUntilNodes is like ParentsUntilNodes, with the
+// option to filter the results based on a selector string. It returns a new
+// Selection object containing the matched elements.
+func (s *Selection) ParentsFilteredUntilNodes(filterSelector string, nodes ...*html.Node) *Selection {
+	return filterAndPush(s, getParentsNodes(s.Nodes, nil, nodes), compileMatcher(filterSelector))
+}
+
+// ParentsMatcherUntilNodes is like ParentsUntilNodes, with the
+// option to filter the results based on a matcher. It returns a new
+// Selection object containing the matched elements.
+func (s *Selection) ParentsMatcherUntilNodes(filter Matcher, nodes ...*html.Node) *Selection {
+	return filterAndPush(s, getParentsNodes(s.Nodes, nil, nodes), filter)
+}
+
+// Siblings gets the siblings of each element in the Selection. It returns
+// a new Selection object containing the matched elements.
+func (s *Selection) Siblings() *Selection {
+	return pushStack(s, getSiblingNodes(s.Nodes, siblingAll, nil, nil))
+}
+
+// SiblingsFiltered gets the siblings of each element in the Selection
+// filtered by a selector. It returns a new Selection object containing the
+// matched elements.
+func (s *Selection) SiblingsFiltered(selector string) *Selection {
+	return filterAndPush(s, getSiblingNodes(s.Nodes, siblingAll, nil, nil), compileMatcher(selector))
+}
+
+// SiblingsMatcher gets the siblings of each element in the Selection
+// filtered by a matcher. It returns a new Selection object containing the
+// matched elements.
+func (s *Selection) SiblingsMatcher(m Matcher) *Selection {
+	return filterAndPush(s, getSiblingNodes(s.Nodes, siblingAll, nil, nil), m)
+}
+
+// Next gets the immediately following sibling of each element in the
+// Selection. It returns a new Selection object containing the matched elements.
+func (s *Selection) Next() *Selection {
+	return pushStack(s, getSiblingNodes(s.Nodes, siblingNext, nil, nil))
+}
+
+// NextFiltered gets the immediately following sibling of each element in the
+// Selection filtered by a selector. It returns a new Selection object
+// containing the matched elements.
+func (s *Selection) NextFiltered(selector string) *Selection {
+	return filterAndPush(s, getSiblingNodes(s.Nodes, siblingNext, nil, nil), compileMatcher(selector))
+}
+
+// NextMatcher gets the immediately following sibling of each element in the
+// Selection filtered by a matcher. It returns a new Selection object
+// containing the matched elements.
+func (s *Selection) NextMatcher(m Matcher) *Selection {
+	return filterAndPush(s, getSiblingNodes(s.Nodes, siblingNext, nil, nil), m)
+}
+
+// NextAll gets all the following siblings of each element in the
+// Selection. It returns a new Selection object containing the matched elements.
+func (s *Selection) NextAll() *Selection {
+	return pushStack(s, getSiblingNodes(s.Nodes, siblingNextAll, nil, nil))
+}
+
+// NextAllFiltered gets all the following siblings of each element in the
+// Selection filtered by a selector. It returns a new Selection object
+// containing the matched elements.
+func (s *Selection) NextAllFiltered(selector string) *Selection {
+	return filterAndPush(s, getSiblingNodes(s.Nodes, siblingNextAll, nil, nil), compileMatcher(selector))
+}
+
+// NextAllMatcher gets all the following siblings of each element in the
+// Selection filtered by a matcher. It returns a new Selection object
+// containing the matched elements.
+func (s *Selection) NextAllMatcher(m Matcher) *Selection {
+	return filterAndPush(s, getSiblingNodes(s.Nodes, siblingNextAll, nil, nil), m)
+}
+
+// Prev gets the immediately preceding sibling of each element in the
+// Selection. It returns a new Selection object containing the matched elements.
+func (s *Selection) Prev() *Selection {
+	return pushStack(s, getSiblingNodes(s.Nodes, siblingPrev, nil, nil))
+}
+
+// PrevFiltered gets the immediately preceding sibling of each element in the
+// Selection filtered by a selector. It returns a new Selection object
+// containing the matched elements.
+func (s *Selection) PrevFiltered(selector string) *Selection {
+	return filterAndPush(s, getSiblingNodes(s.Nodes, siblingPrev, nil, nil), compileMatcher(selector))
+}
+
+// PrevMatcher gets the immediately preceding sibling of each element in the
+// Selection filtered by a matcher. It returns a new Selection object
+// containing the matched elements.
+func (s *Selection) PrevMatcher(m Matcher) *Selection {
+	return filterAndPush(s, getSiblingNodes(s.Nodes, siblingPrev, nil, nil), m)
+}
+
+// PrevAll gets all the preceding siblings of each element in the
+// Selection. It returns a new Selection object containing the matched elements.
+func (s *Selection) PrevAll() *Selection {
+	return pushStack(s, getSiblingNodes(s.Nodes, siblingPrevAll, nil, nil))
+}
+
+// PrevAllFiltered gets all the preceding siblings of each element in the
+// Selection filtered by a selector. It returns a new Selection object
+// containing the matched elements.
+func (s *Selection) PrevAllFiltered(selector string) *Selection {
+	return filterAndPush(s, getSiblingNodes(s.Nodes, siblingPrevAll, nil, nil), compileMatcher(selector))
+}
+
+// PrevAllMatcher gets all the preceding siblings of each element in the
+// Selection filtered by a matcher. It returns a new Selection object
+// containing the matched elements.
+func (s *Selection) PrevAllMatcher(m Matcher) *Selection {
+	return filterAndPush(s, getSiblingNodes(s.Nodes, siblingPrevAll, nil, nil), m)
+}
+
+// NextUntil gets all following siblings of each element up to but not
+// including the element matched by the selector. It returns a new Selection
+// object containing the matched elements.
+func (s *Selection) NextUntil(selector string) *Selection {
+	return pushStack(s, getSiblingNodes(s.Nodes, siblingNextUntil,
+		compileMatcher(selector), nil))
+}
+
+// NextUntilMatcher gets all following siblings of each element up to but not
+// including the element matched by the matcher. It returns a new Selection
+// object containing the matched elements.
+func (s *Selection) NextUntilMatcher(m Matcher) *Selection {
+	return pushStack(s, getSiblingNodes(s.Nodes, siblingNextUntil,
+		m, nil))
+}
+
+// NextUntilSelection gets all following siblings of each element up to but not
+// including the element matched by the Selection. It returns a new Selection
+// object containing the matched elements.
+func (s *Selection) NextUntilSelection(sel *Selection) *Selection {
+	if sel == nil {
+		return s.NextAll()
+	}
+	return s.NextUntilNodes(sel.Nodes...)
+}
+
+// NextUntilNodes gets all following siblings of each element up to but not
+// including the element matched by the nodes. It returns a new Selection
+// object containing the matched elements.
+func (s *Selection) NextUntilNodes(nodes ...*html.Node) *Selection {
+	return pushStack(s, getSiblingNodes(s.Nodes, siblingNextUntil,
+		nil, nodes))
+}
+
+// PrevUntil gets all preceding siblings of each element up to but not
+// including the element matched by the selector. It returns a new Selection
+// object containing the matched elements.
+func (s *Selection) PrevUntil(selector string) *Selection {
+	return pushStack(s, getSiblingNodes(s.Nodes, siblingPrevUntil,
+		compileMatcher(selector), nil))
+}
+
+// PrevUntilMatcher gets all preceding siblings of each element up to but not
+// including the element matched by the matcher. It returns a new Selection
+// object containing the matched elements.
+func (s *Selection) PrevUntilMatcher(m Matcher) *Selection {
+	return pushStack(s, getSiblingNodes(s.Nodes, siblingPrevUntil,
+		m, nil))
+}
+
+// PrevUntilSelection gets all preceding siblings of each element up to but not
+// including the element matched by the Selection. It returns a new Selection
+// object containing the matched elements.
+func (s *Selection) PrevUntilSelection(sel *Selection) *Selection {
+	if sel == nil {
+		return s.PrevAll()
+	}
+	return s.PrevUntilNodes(sel.Nodes...)
+}
+
+// PrevUntilNodes gets all preceding siblings of each element up to but not
+// including the element matched by the nodes. It returns a new Selection
+// object containing the matched elements.
+func (s *Selection) PrevUntilNodes(nodes ...*html.Node) *Selection {
+	return pushStack(s, getSiblingNodes(s.Nodes, siblingPrevUntil,
+		nil, nodes))
+}
+
+// NextFilteredUntil is like NextUntil, with the option to filter
+// the results based on a selector string.
+// It returns a new Selection object containing the matched elements.
+func (s *Selection) NextFilteredUntil(filterSelector, untilSelector string) *Selection {
+	return filterAndPush(s, getSiblingNodes(s.Nodes, siblingNextUntil,
+		compileMatcher(untilSelector), nil), compileMatcher(filterSelector))
+}
+
+// NextFilteredUntilMatcher is like NextUntilMatcher, with the option to filter
+// the results based on a matcher.
+// It returns a new Selection object containing the matched elements.
+func (s *Selection) NextFilteredUntilMatcher(filter, until Matcher) *Selection {
+	return filterAndPush(s, getSiblingNodes(s.Nodes, siblingNextUntil,
+		until, nil), filter)
+}
+
+// NextFilteredUntilSelection is like NextUntilSelection, with the
+// option to filter the results based on a selector string. It returns a new
+// Selection object containing the matched elements.
+func (s *Selection) NextFilteredUntilSelection(filterSelector string, sel *Selection) *Selection {
+	return s.NextMatcherUntilSelection(compileMatcher(filterSelector), sel)
+}
+
+// NextMatcherUntilSelection is like NextUntilSelection, with the
+// option to filter the results based on a matcher. It returns a new
+// Selection object containing the matched elements.
+func (s *Selection) NextMatcherUntilSelection(filter Matcher, sel *Selection) *Selection {
+	if sel == nil {
+		return s.NextMatcher(filter)
+	}
+	return s.NextMatcherUntilNodes(filter, sel.Nodes...)
+}
+
+// NextFilteredUntilNodes is like NextUntilNodes, with the
+// option to filter the results based on a selector string. It returns a new
+// Selection object containing the matched elements.
+func (s *Selection) NextFilteredUntilNodes(filterSelector string, nodes ...*html.Node) *Selection {
+	return filterAndPush(s, getSiblingNodes(s.Nodes, siblingNextUntil,
+		nil, nodes), compileMatcher(filterSelector))
+}
+
+// NextMatcherUntilNodes is like NextUntilNodes, with the
+// option to filter the results based on a matcher. It returns a new
+// Selection object containing the matched elements.
+func (s *Selection) NextMatcherUntilNodes(filter Matcher, nodes ...*html.Node) *Selection {
+	return filterAndPush(s, getSiblingNodes(s.Nodes, siblingNextUntil,
+		nil, nodes), filter)
+}
+
+// PrevFilteredUntil is like PrevUntil, with the option to filter
+// the results based on a selector string.
+// It returns a new Selection object containing the matched elements.
+func (s *Selection) PrevFilteredUntil(filterSelector, untilSelector string) *Selection {
+	return filterAndPush(s, getSiblingNodes(s.Nodes, siblingPrevUntil,
+		compileMatcher(untilSelector), nil), compileMatcher(filterSelector))
+}
+
+// PrevFilteredUntilMatcher is like PrevUntilMatcher, with the option to filter
+// the results based on a matcher.
+// It returns a new Selection object containing the matched elements.
+func (s *Selection) PrevFilteredUntilMatcher(filter, until Matcher) *Selection {
+	return filterAndPush(s, getSiblingNodes(s.Nodes, siblingPrevUntil,
+		until, nil), filter)
+}
+
+// PrevFilteredUntilSelection is like PrevUntilSelection, with the
+// option to filter the results based on a selector string. It returns a new
+// Selection object containing the matched elements.
+func (s *Selection) PrevFilteredUntilSelection(filterSelector string, sel *Selection) *Selection {
+	return s.PrevMatcherUntilSelection(compileMatcher(filterSelector), sel)
+}
+
+// PrevMatcherUntilSelection is like PrevUntilSelection, with the
+// option to filter the results based on a matcher. It returns a new
+// Selection object containing the matched elements.
+func (s *Selection) PrevMatcherUntilSelection(filter Matcher, sel *Selection) *Selection {
+	if sel == nil {
+		return s.PrevMatcher(filter)
+	}
+	return s.PrevMatcherUntilNodes(filter, sel.Nodes...)
+}
+
+// PrevFilteredUntilNodes is like PrevUntilNodes, with the
+// option to filter the results based on a selector string. It returns a new
+// Selection object containing the matched elements.
+func (s *Selection) PrevFilteredUntilNodes(filterSelector string, nodes ...*html.Node) *Selection {
+	return filterAndPush(s, getSiblingNodes(s.Nodes, siblingPrevUntil,
+		nil, nodes), compileMatcher(filterSelector))
+}
+
+// PrevMatcherUntilNodes is like PrevUntilNodes, with the
+// option to filter the results based on a matcher. It returns a new
+// Selection object containing the matched elements.
+func (s *Selection) PrevMatcherUntilNodes(filter Matcher, nodes ...*html.Node) *Selection {
+	return filterAndPush(s, getSiblingNodes(s.Nodes, siblingPrevUntil,
+		nil, nodes), filter)
+}
+
+// Filter and push filters the nodes based on a matcher, and pushes the results
+// on the stack, with the srcSel as previous selection.
+func filterAndPush(srcSel *Selection, nodes []*html.Node, m Matcher) *Selection {
+	// Create a temporary Selection with the specified nodes to filter using winnow
+	sel := &Selection{nodes, srcSel.document, nil}
+	// Filter based on matcher and push on stack
+	return pushStack(srcSel, winnow(sel, m, true))
+}
+
+// Internal implementation of Find that return raw nodes.
+func findWithMatcher(nodes []*html.Node, m Matcher) []*html.Node {
+	// Map nodes to find the matches within the children of each node
+	return mapNodes(nodes, func(i int, n *html.Node) (result []*html.Node) {
+		// Go down one level, becausejQuery's Find selects only within descendants
+		for c := n.FirstChild; c != nil; c = c.NextSibling {
+			if c.Type == html.ElementNode {
+				result = append(result, m.MatchAll(c)...)
+			}
+		}
+		return
+	})
+}
+
+// Internal implementation to get all parent nodes, stopping at the specified
+// node (or nil if no stop).
+func getParentsNodes(nodes []*html.Node, stopm Matcher, stopNodes []*html.Node) []*html.Node {
+	return mapNodes(nodes, func(i int, n *html.Node) (result []*html.Node) {
+		for p := n.Parent; p != nil; p = p.Parent {
+			sel := newSingleSelection(p, nil)
+			if stopm != nil {
+				if sel.IsMatcher(stopm) {
+					break
+				}
+			} else if len(stopNodes) > 0 {
+				if sel.IsNodes(stopNodes...) {
+					break
+				}
+			}
+			if p.Type == html.ElementNode {
+				result = append(result, p)
+			}
+		}
+		return
+	})
+}
+
+// Internal implementation of sibling nodes that return a raw slice of matches.
+func getSiblingNodes(nodes []*html.Node, st siblingType, untilm Matcher, untilNodes []*html.Node) []*html.Node {
+	var f func(*html.Node) bool
+
+	// If the requested siblings are ...Until, create the test function to
+	// determine if the until condition is reached (returns true if it is)
+	if st == siblingNextUntil || st == siblingPrevUntil {
+		f = func(n *html.Node) bool {
+			if untilm != nil {
+				// Matcher-based condition
+				sel := newSingleSelection(n, nil)
+				return sel.IsMatcher(untilm)
+			} else if len(untilNodes) > 0 {
+				// Nodes-based condition
+				sel := newSingleSelection(n, nil)
+				return sel.IsNodes(untilNodes...)
+			}
+			return false
+		}
+	}
+
+	return mapNodes(nodes, func(i int, n *html.Node) []*html.Node {
+		return getChildrenWithSiblingType(n.Parent, st, n, f)
+	})
+}
+
+// Gets the children nodes of each node in the specified slice of nodes,
+// based on the sibling type request.
+func getChildrenNodes(nodes []*html.Node, st siblingType) []*html.Node {
+	return mapNodes(nodes, func(i int, n *html.Node) []*html.Node {
+		return getChildrenWithSiblingType(n, st, nil, nil)
+	})
+}
+
+// Gets the children of the specified parent, based on the requested sibling
+// type, skipping a specified node if required.
+func getChildrenWithSiblingType(parent *html.Node, st siblingType, skipNode *html.Node,
+	untilFunc func(*html.Node) bool) (result []*html.Node) {
+
+	// Create the iterator function
+	var iter = func(cur *html.Node) (ret *html.Node) {
+		// Based on the sibling type requested, iterate the right way
+		for {
+			switch st {
+			case siblingAll, siblingAllIncludingNonElements:
+				if cur == nil {
+					// First iteration, start with first child of parent
+					// Skip node if required
+					if ret = parent.FirstChild; ret == skipNode && skipNode != nil {
+						ret = skipNode.NextSibling
+					}
+				} else {
+					// Skip node if required
+					if ret = cur.NextSibling; ret == skipNode && skipNode != nil {
+						ret = skipNode.NextSibling
+					}
+				}
+			case siblingPrev, siblingPrevAll, siblingPrevUntil:
+				if cur == nil {
+					// Start with previous sibling of the skip node
+					ret = skipNode.PrevSibling
+				} else {
+					ret = cur.PrevSibling
+				}
+			case siblingNext, siblingNextAll, siblingNextUntil:
+				if cur == nil {
+					// Start with next sibling of the skip node
+					ret = skipNode.NextSibling
+				} else {
+					ret = cur.NextSibling
+				}
+			default:
+				panic("Invalid sibling type.")
+			}
+			if ret == nil || ret.Type == html.ElementNode || st == siblingAllIncludingNonElements {
+				return
+			}
+			// Not a valid node, try again from this one
+			cur = ret
+		}
+	}
+
+	for c := iter(nil); c != nil; c = iter(c) {
+		// If this is an ...Until case, test before append (returns true
+		// if the until condition is reached)
+		if st == siblingNextUntil || st == siblingPrevUntil {
+			if untilFunc(c) {
+				return
+			}
+		}
+		result = append(result, c)
+		if st == siblingNext || st == siblingPrev {
+			// Only one node was requested (immediate next or previous), so exit
+			return
+		}
+	}
+	return
+}
+
+// Internal implementation of parent nodes that return a raw slice of Nodes.
+func getParentNodes(nodes []*html.Node) []*html.Node {
+	return mapNodes(nodes, func(i int, n *html.Node) []*html.Node {
+		if n.Parent != nil && n.Parent.Type == html.ElementNode {
+			return []*html.Node{n.Parent}
+		}
+		return nil
+	})
+}
+
+// Internal map function used by many traversing methods. Takes the source nodes
+// to iterate on and the mapping function that returns an array of nodes.
+// Returns an array of nodes mapped by calling the callback function once for
+// each node in the source nodes.
+func mapNodes(nodes []*html.Node, f func(int, *html.Node) []*html.Node) (result []*html.Node) {
+	set := make(map[*html.Node]bool)
+	for i, n := range nodes {
+		if vals := f(i, n); len(vals) > 0 {
+			result = appendWithoutDuplicates(result, vals, set)
+		}
+	}
+	return result
+}

vendor/github.com/PuerkitoBio/goquery/type.go

@@ -0,0 +1,203 @@
+package goquery
+
+import (
+	"errors"
+	"io"
+	"net/http"
+	"net/url"
+
+	"github.com/andybalholm/cascadia"
+	"golang.org/x/net/html"
+)
+
+// Document represents an HTML document to be manipulated. Unlike jQuery, which
+// is loaded as part of a DOM document, and thus acts upon its containing
+// document, GoQuery doesn't know which HTML document to act upon. So it needs
+// to be told, and that's what the Document class is for. It holds the root
+// document node to manipulate, and can make selections on this document.
+type Document struct {
+	*Selection
+	Url      *url.URL
+	rootNode *html.Node
+}
+
+// NewDocumentFromNode is a Document constructor that takes a root html Node
+// as argument.
+func NewDocumentFromNode(root *html.Node) *Document {
+	return newDocument(root, nil)
+}
+
+// NewDocument is a Document constructor that takes a string URL as argument.
+// It loads the specified document, parses it, and stores the root Document
+// node, ready to be manipulated.
+//
+// Deprecated: Use the net/http standard library package to make the request
+// and validate the response before calling goquery.NewDocumentFromReader
+// with the response's body.
+func NewDocument(url string) (*Document, error) {
+	// Load the URL
+	res, e := http.Get(url)
+	if e != nil {
+		return nil, e
+	}
+	return NewDocumentFromResponse(res)
+}
+
+// NewDocumentFromReader returns a Document from an io.Reader.
+// It returns an error as second value if the reader's data cannot be parsed
+// as html. It does not check if the reader is also an io.Closer, the
+// provided reader is never closed by this call. It is the responsibility
+// of the caller to close it if required.
+func NewDocumentFromReader(r io.Reader) (*Document, error) {
+	root, e := html.Parse(r)
+	if e != nil {
+		return nil, e
+	}
+	return newDocument(root, nil), nil
+}
+
+// NewDocumentFromResponse is another Document constructor that takes an http response as argument.
+// It loads the specified response's document, parses it, and stores the root Document
+// node, ready to be manipulated. The response's body is closed on return.
+//
+// Deprecated: Use goquery.NewDocumentFromReader with the response's body.
+func NewDocumentFromResponse(res *http.Response) (*Document, error) {
+	if res == nil {
+		return nil, errors.New("Response is nil")
+	}
+	defer res.Body.Close()
+	if res.Request == nil {
+		return nil, errors.New("Response.Request is nil")
+	}
+
+	// Parse the HTML into nodes
+	root, e := html.Parse(res.Body)
+	if e != nil {
+		return nil, e
+	}
+
+	// Create and fill the document
+	return newDocument(root, res.Request.URL), nil
+}
+
+// CloneDocument creates a deep-clone of a document.
+func CloneDocument(doc *Document) *Document {
+	return newDocument(cloneNode(doc.rootNode), doc.Url)
+}
+
+// Private constructor, make sure all fields are correctly filled.
+func newDocument(root *html.Node, url *url.URL) *Document {
+	// Create and fill the document
+	d := &Document{nil, url, root}
+	d.Selection = newSingleSelection(root, d)
+	return d
+}
+
+// Selection represents a collection of nodes matching some criteria. The
+// initial Selection can be created by using Document.Find, and then
+// manipulated using the jQuery-like chainable syntax and methods.
+type Selection struct {
+	Nodes    []*html.Node
+	document *Document
+	prevSel  *Selection
+}
+
+// Helper constructor to create an empty selection
+func newEmptySelection(doc *Document) *Selection {
+	return &Selection{nil, doc, nil}
+}
+
+// Helper constructor to create a selection of only one node
+func newSingleSelection(node *html.Node, doc *Document) *Selection {
+	return &Selection{[]*html.Node{node}, doc, nil}
+}
+
+// Matcher is an interface that defines the methods to match
+// HTML nodes against a compiled selector string. Cascadia's
+// Selector implements this interface.
+type Matcher interface {
+	Match(*html.Node) bool
+	MatchAll(*html.Node) []*html.Node
+	Filter([]*html.Node) []*html.Node
+}
+
+// Single compiles a selector string to a Matcher that stops after the first
+// match is found.
+//
+// By default, Selection.Find and other functions that accept a selector string
+// to select nodes will use all matches corresponding to that selector. By
+// using the Matcher returned by Single, at most the first match will be
+// selected.
+//
+// For example, those two statements are semantically equivalent:
+//
+//     sel1 := doc.Find("a").First()
+//     sel2 := doc.FindMatcher(goquery.Single("a"))
+//
+// The one using Single is optimized to be potentially much faster on large
+// documents.
+//
+// Only the behaviour of the MatchAll method of the Matcher interface is
+// altered compared to standard Matchers. This means that the single-selection
+// property of the Matcher only applies for Selection methods where the Matcher
+// is used to select nodes, not to filter or check if a node matches the
+// Matcher - in those cases, the behaviour of the Matcher is unchanged (e.g.
+// FilterMatcher(Single("div")) will still result in a Selection with multiple
+// "div"s if there were many "div"s in the Selection to begin with).
+func Single(selector string) Matcher {
+	return singleMatcher{compileMatcher(selector)}
+}
+
+// SingleMatcher returns a Matcher matches the same nodes as m, but that stops
+// after the first match is found.
+//
+// See the documentation of function Single for more details.
+func SingleMatcher(m Matcher) Matcher {
+	if _, ok := m.(singleMatcher); ok {
+		// m is already a singleMatcher
+		return m
+	}
+	return singleMatcher{m}
+}
+
+// compileMatcher compiles the selector string s and returns
+// the corresponding Matcher. If s is an invalid selector string,
+// it returns a Matcher that fails all matches.
+func compileMatcher(s string) Matcher {
+	cs, err := cascadia.Compile(s)
+	if err != nil {
+		return invalidMatcher{}
+	}
+	return cs
+}
+
+type singleMatcher struct {
+	Matcher
+}
+
+func (m singleMatcher) MatchAll(n *html.Node) []*html.Node {
+	// Optimized version - stops finding at the first match (cascadia-compiled
+	// matchers all use this code path).
+	if mm, ok := m.Matcher.(interface{ MatchFirst(*html.Node) *html.Node }); ok {
+		node := mm.MatchFirst(n)
+		if node == nil {
+			return nil
+		}
+		return []*html.Node{node}
+	}
+
+	// Fallback version, for e.g. test mocks that don't provide the MatchFirst
+	// method.
+	nodes := m.Matcher.MatchAll(n)
+	if len(nodes) > 0 {
+		return nodes[:1:1]
+	}
+	return nil
+}
+
+// invalidMatcher is a Matcher that always fails to match.
+type invalidMatcher struct{}
+
+func (invalidMatcher) Match(n *html.Node) bool             { return false }
+func (invalidMatcher) MatchAll(n *html.Node) []*html.Node  { return nil }
+func (invalidMatcher) Filter(ns []*html.Node) []*html.Node { return nil }

vendor/github.com/PuerkitoBio/goquery/utilities.go

@@ -0,0 +1,171 @@
+package goquery
+
+import (
+	"bytes"
+
+	"golang.org/x/net/html"
+)
+
+// used to determine if a set (map[*html.Node]bool) should be used
+// instead of iterating over a slice. The set uses more memory and
+// is slower than slice iteration for small N.
+const minNodesForSet = 1000
+
+var nodeNames = []string{
+	html.ErrorNode:    "#error",
+	html.TextNode:     "#text",
+	html.DocumentNode: "#document",
+	html.CommentNode:  "#comment",
+}
+
+// NodeName returns the node name of the first element in the selection.
+// It tries to behave in a similar way as the DOM's nodeName property
+// (https://developer.mozilla.org/en-US/docs/Web/API/Node/nodeName).
+//
+// Go's net/html package defines the following node types, listed with
+// the corresponding returned value from this function:
+//
+//     ErrorNode : #error
+//     TextNode : #text
+//     DocumentNode : #document
+//     ElementNode : the element's tag name
+//     CommentNode : #comment
+//     DoctypeNode : the name of the document type
+//
+func NodeName(s *Selection) string {
+	if s.Length() == 0 {
+		return ""
+	}
+	return nodeName(s.Get(0))
+}
+
+// nodeName returns the node name of the given html node.
+// See NodeName for additional details on behaviour.
+func nodeName(node *html.Node) string {
+	if node == nil {
+		return ""
+	}
+
+	switch node.Type {
+	case html.ElementNode, html.DoctypeNode:
+		return node.Data
+	default:
+		if node.Type >= 0 && int(node.Type) < len(nodeNames) {
+			return nodeNames[node.Type]
+		}
+		return ""
+	}
+}
+
+// OuterHtml returns the outer HTML rendering of the first item in
+// the selection - that is, the HTML including the first element's
+// tag and attributes.
+//
+// Unlike InnerHtml, this is a function and not a method on the Selection,
+// because this is not a jQuery method (in javascript-land, this is
+// a property provided by the DOM).
+func OuterHtml(s *Selection) (string, error) {
+	var buf bytes.Buffer
+
+	if s.Length() == 0 {
+		return "", nil
+	}
+	n := s.Get(0)
+	if err := html.Render(&buf, n); err != nil {
+		return "", err
+	}
+	return buf.String(), nil
+}
+
+// Loop through all container nodes to search for the target node.
+func sliceContains(container []*html.Node, contained *html.Node) bool {
+	for _, n := range container {
+		if nodeContains(n, contained) {
+			return true
+		}
+	}
+
+	return false
+}
+
+// Checks if the contained node is within the container node.
+func nodeContains(container *html.Node, contained *html.Node) bool {
+	// Check if the parent of the contained node is the container node, traversing
+	// upward until the top is reached, or the container is found.
+	for contained = contained.Parent; contained != nil; contained = contained.Parent {
+		if container == contained {
+			return true
+		}
+	}
+	return false
+}
+
+// Checks if the target node is in the slice of nodes.
+func isInSlice(slice []*html.Node, node *html.Node) bool {
+	return indexInSlice(slice, node) > -1
+}
+
+// Returns the index of the target node in the slice, or -1.
+func indexInSlice(slice []*html.Node, node *html.Node) int {
+	if node != nil {
+		for i, n := range slice {
+			if n == node {
+				return i
+			}
+		}
+	}
+	return -1
+}
+
+// Appends the new nodes to the target slice, making sure no duplicate is added.
+// There is no check to the original state of the target slice, so it may still
+// contain duplicates. The target slice is returned because append() may create
+// a new underlying array. If targetSet is nil, a local set is created with the
+// target if len(target) + len(nodes) is greater than minNodesForSet.
+func appendWithoutDuplicates(target []*html.Node, nodes []*html.Node, targetSet map[*html.Node]bool) []*html.Node {
+	// if there are not that many nodes, don't use the map, faster to just use nested loops
+	// (unless a non-nil targetSet is passed, in which case the caller knows better).
+	if targetSet == nil && len(target)+len(nodes) < minNodesForSet {
+		for _, n := range nodes {
+			if !isInSlice(target, n) {
+				target = append(target, n)
+			}
+		}
+		return target
+	}
+
+	// if a targetSet is passed, then assume it is reliable, otherwise create one
+	// and initialize it with the current target contents.
+	if targetSet == nil {
+		targetSet = make(map[*html.Node]bool, len(target))
+		for _, n := range target {
+			targetSet[n] = true
+		}
+	}
+	for _, n := range nodes {
+		if !targetSet[n] {
+			target = append(target, n)
+			targetSet[n] = true
+		}
+	}
+
+	return target
+}
+
+// Loop through a selection, returning only those nodes that pass the predicate
+// function.
+func grep(sel *Selection, predicate func(i int, s *Selection) bool) (result []*html.Node) {
+	for i, n := range sel.Nodes {
+		if predicate(i, newSingleSelection(n, sel.document)) {
+			result = append(result, n)
+		}
+	}
+	return result
+}
+
+// Creates a new Selection object based on the specified nodes, and keeps the
+// source Selection object on the stack (linked list).
+func pushStack(fromSel *Selection, nodes []*html.Node) *Selection {
+	result := &Selection{nodes, fromSel.document, fromSel}
+	return result
+}

vendor/github.com/andybalholm/cascadia/.travis.yml

@@ -0,0 +1,14 @@
+language: go
+
+go:
+  - 1.3
+  - 1.4
+
+install:
+  - go get github.com/andybalholm/cascadia
+
+script:
+ - go test -v
+
+notifications:
+  email: false

vendor/github.com/andybalholm/cascadia/LICENSE

@@ -0,0 +1,24 @@
+Copyright (c) 2011 Andy Balholm. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/github.com/andybalholm/cascadia/README.md

@@ -0,0 +1,9 @@
+# cascadia
+
+[![](https://travis-ci.org/andybalholm/cascadia.svg)](https://travis-ci.org/andybalholm/cascadia)
+
+The Cascadia package implements CSS selectors for use with the parse trees produced by the html package.
+
+To test CSS selectors without writing Go code, check out [cascadia](https://github.com/suntong/cascadia) the command line tool, a thin wrapper around this package.
+
+[Refer to godoc here](https://godoc.org/github.com/andybalholm/cascadia).

vendor/github.com/andybalholm/cascadia/go.mod

@@ -0,0 +1,3 @@
+module "github.com/andybalholm/cascadia"
+
+require "golang.org/x/net" v0.0.0-20180218175443-cbe0f9307d01

vendor/github.com/andybalholm/cascadia/parser.go

@@ -0,0 +1,801 @@
+// Package cascadia is an implementation of CSS selectors.
+package cascadia
+
+import (
+	"errors"
+	"fmt"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+// a parser for CSS selectors
+type parser struct {
+	s string // the source text
+	i int    // the current position
+}
+
+// parseEscape parses a backslash escape.
+func (p *parser) parseEscape() (result string, err error) {
+	if len(p.s) < p.i+2 || p.s[p.i] != '\\' {
+		return "", errors.New("invalid escape sequence")
+	}
+
+	start := p.i + 1
+	c := p.s[start]
+	switch {
+	case c == '\r' || c == '\n' || c == '\f':
+		return "", errors.New("escaped line ending outside string")
+	case hexDigit(c):
+		// unicode escape (hex)
+		var i int
+		for i = start; i < p.i+6 && i < len(p.s) && hexDigit(p.s[i]); i++ {
+			// empty
+		}
+		v, _ := strconv.ParseUint(p.s[start:i], 16, 21)
+		if len(p.s) > i {
+			switch p.s[i] {
+			case '\r':
+				i++
+				if len(p.s) > i && p.s[i] == '\n' {
+					i++
+				}
+			case ' ', '\t', '\n', '\f':
+				i++
+			}
+		}
+		p.i = i
+		return string(rune(v)), nil
+	}
+
+	// Return the literal character after the backslash.
+	result = p.s[start : start+1]
+	p.i += 2
+	return result, nil
+}
+
+// toLowerASCII returns s with all ASCII capital letters lowercased.
+func toLowerASCII(s string) string {
+	var b []byte
+	for i := 0; i < len(s); i++ {
+		if c := s[i]; 'A' <= c && c <= 'Z' {
+			if b == nil {
+				b = make([]byte, len(s))
+				copy(b, s)
+			}
+			b[i] = s[i] + ('a' - 'A')
+		}
+	}
+
+	if b == nil {
+		return s
+	}
+
+	return string(b)
+}
+
+func hexDigit(c byte) bool {
+	return '0' <= c && c <= '9' || 'a' <= c && c <= 'f' || 'A' <= c && c <= 'F'
+}
+
+// nameStart returns whether c can be the first character of an identifier
+// (not counting an initial hyphen, or an escape sequence).
+func nameStart(c byte) bool {
+	return 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z' || c == '_' || c > 127
+}
+
+// nameChar returns whether c can be a character within an identifier
+// (not counting an escape sequence).
+func nameChar(c byte) bool {
+	return 'a' <= c && c <= 'z' || 'A' <= c && c <= 'Z' || c == '_' || c > 127 ||
+		c == '-' || '0' <= c && c <= '9'
+}
+
+// parseIdentifier parses an identifier.
+func (p *parser) parseIdentifier() (result string, err error) {
+	startingDash := false
+	if len(p.s) > p.i && p.s[p.i] == '-' {
+		startingDash = true
+		p.i++
+	}
+
+	if len(p.s) <= p.i {
+		return "", errors.New("expected identifier, found EOF instead")
+	}
+
+	if c := p.s[p.i]; !(nameStart(c) || c == '\\') {
+		return "", fmt.Errorf("expected identifier, found %c instead", c)
+	}
+
+	result, err = p.parseName()
+	if startingDash && err == nil {
+		result = "-" + result
+	}
+	return
+}
+
+// parseName parses a name (which is like an identifier, but doesn't have
+// extra restrictions on the first character).
+func (p *parser) parseName() (result string, err error) {
+	i := p.i
+loop:
+	for i < len(p.s) {
+		c := p.s[i]
+		switch {
+		case nameChar(c):
+			start := i
+			for i < len(p.s) && nameChar(p.s[i]) {
+				i++
+			}
+			result += p.s[start:i]
+		case c == '\\':
+			p.i = i
+			val, err := p.parseEscape()
+			if err != nil {
+				return "", err
+			}
+			i = p.i
+			result += val
+		default:
+			break loop
+		}
+	}
+
+	if result == "" {
+		return "", errors.New("expected name, found EOF instead")
+	}
+
+	p.i = i
+	return result, nil
+}
+
+// parseString parses a single- or double-quoted string.
+func (p *parser) parseString() (result string, err error) {
+	i := p.i
+	if len(p.s) < i+2 {
+		return "", errors.New("expected string, found EOF instead")
+	}
+
+	quote := p.s[i]
+	i++
+
+loop:
+	for i < len(p.s) {
+		switch p.s[i] {
+		case '\\':
+			if len(p.s) > i+1 {
+				switch c := p.s[i+1]; c {
+				case '\r':
+					if len(p.s) > i+2 && p.s[i+2] == '\n' {
+						i += 3
+						continue loop
+					}
+					fallthrough
+				case '\n', '\f':
+					i += 2
+					continue loop
+				}
+			}
+			p.i = i
+			val, err := p.parseEscape()
+			if err != nil {
+				return "", err
+			}
+			i = p.i
+			result += val
+		case quote:
+			break loop
+		case '\r', '\n', '\f':
+			return "", errors.New("unexpected end of line in string")
+		default:
+			start := i
+			for i < len(p.s) {
+				if c := p.s[i]; c == quote || c == '\\' || c == '\r' || c == '\n' || c == '\f' {
+					break
+				}
+				i++
+			}
+			result += p.s[start:i]
+		}
+	}
+
+	if i >= len(p.s) {
+		return "", errors.New("EOF in string")
+	}
+
+	// Consume the final quote.
+	i++
+
+	p.i = i
+	return result, nil
+}
+
+// parseRegex parses a regular expression; the end is defined by encountering an
+// unmatched closing ')' or ']' which is not consumed
+func (p *parser) parseRegex() (rx *regexp.Regexp, err error) {
+	i := p.i
+	if len(p.s) < i+2 {
+		return nil, errors.New("expected regular expression, found EOF instead")
+	}
+
+	// number of open parens or brackets;
+	// when it becomes negative, finished parsing regex
+	open := 0
+
+loop:
+	for i < len(p.s) {
+		switch p.s[i] {
+		case '(', '[':
+			open++
+		case ')', ']':
+			open--
+			if open < 0 {
+				break loop
+			}
+		}
+		i++
+	}
+
+	if i >= len(p.s) {
+		return nil, errors.New("EOF in regular expression")
+	}
+	rx, err = regexp.Compile(p.s[p.i:i])
+	p.i = i
+	return rx, err
+}
+
+// skipWhitespace consumes whitespace characters and comments.
+// It returns true if there was actually anything to skip.
+func (p *parser) skipWhitespace() bool {
+	i := p.i
+	for i < len(p.s) {
+		switch p.s[i] {
+		case ' ', '\t', '\r', '\n', '\f':
+			i++
+			continue
+		case '/':
+			if strings.HasPrefix(p.s[i:], "/*") {
+				end := strings.Index(p.s[i+len("/*"):], "*/")
+				if end != -1 {
+					i += end + len("/**/")
+					continue
+				}
+			}
+		}
+		break
+	}
+
+	if i > p.i {
+		p.i = i
+		return true
+	}
+
+	return false
+}
+
+// consumeParenthesis consumes an opening parenthesis and any following
+// whitespace. It returns true if there was actually a parenthesis to skip.
+func (p *parser) consumeParenthesis() bool {
+	if p.i < len(p.s) && p.s[p.i] == '(' {
+		p.i++
+		p.skipWhitespace()
+		return true
+	}
+	return false
+}
+
+// consumeClosingParenthesis consumes a closing parenthesis and any preceding
+// whitespace. It returns true if there was actually a parenthesis to skip.
+func (p *parser) consumeClosingParenthesis() bool {
+	i := p.i
+	p.skipWhitespace()
+	if p.i < len(p.s) && p.s[p.i] == ')' {
+		p.i++
+		return true
+	}
+	p.i = i
+	return false
+}
+
+// parseTypeSelector parses a type selector (one that matches by tag name).
+func (p *parser) parseTypeSelector() (result tagSelector, err error) {
+	tag, err := p.parseIdentifier()
+	if err != nil {
+		return
+	}
+	return tagSelector{tag: toLowerASCII(tag)}, nil
+}
+
+// parseIDSelector parses a selector that matches by id attribute.
+func (p *parser) parseIDSelector() (idSelector, error) {
+	if p.i >= len(p.s) {
+		return idSelector{}, fmt.Errorf("expected id selector (#id), found EOF instead")
+	}
+	if p.s[p.i] != '#' {
+		return idSelector{}, fmt.Errorf("expected id selector (#id), found '%c' instead", p.s[p.i])
+	}
+
+	p.i++
+	id, err := p.parseName()
+	if err != nil {
+		return idSelector{}, err
+	}
+
+	return idSelector{id: id}, nil
+}
+
+// parseClassSelector parses a selector that matches by class attribute.
+func (p *parser) parseClassSelector() (classSelector, error) {
+	if p.i >= len(p.s) {
+		return classSelector{}, fmt.Errorf("expected class selector (.class), found EOF instead")
+	}
+	if p.s[p.i] != '.' {
+		return classSelector{}, fmt.Errorf("expected class selector (.class), found '%c' instead", p.s[p.i])
+	}
+
+	p.i++
+	class, err := p.parseIdentifier()
+	if err != nil {
+		return classSelector{}, err
+	}
+
+	return classSelector{class: class}, nil
+}
+
+// parseAttributeSelector parses a selector that matches by attribute value.
+func (p *parser) parseAttributeSelector() (attrSelector, error) {
+	if p.i >= len(p.s) {
+		return attrSelector{}, fmt.Errorf("expected attribute selector ([attribute]), found EOF instead")
+	}
+	if p.s[p.i] != '[' {
+		return attrSelector{}, fmt.Errorf("expected attribute selector ([attribute]), found '%c' instead", p.s[p.i])
+	}
+
+	p.i++
+	p.skipWhitespace()
+	key, err := p.parseIdentifier()
+	if err != nil {
+		return attrSelector{}, err
+	}
+	key = toLowerASCII(key)
+
+	p.skipWhitespace()
+	if p.i >= len(p.s) {
+		return attrSelector{}, errors.New("unexpected EOF in attribute selector")
+	}
+
+	if p.s[p.i] == ']' {
+		p.i++
+		return attrSelector{key: key, operation: ""}, nil
+	}
+
+	if p.i+2 >= len(p.s) {
+		return attrSelector{}, errors.New("unexpected EOF in attribute selector")
+	}
+
+	op := p.s[p.i : p.i+2]
+	if op[0] == '=' {
+		op = "="
+	} else if op[1] != '=' {
+		return attrSelector{}, fmt.Errorf(`expected equality operator, found "%s" instead`, op)
+	}
+	p.i += len(op)
+
+	p.skipWhitespace()
+	if p.i >= len(p.s) {
+		return attrSelector{}, errors.New("unexpected EOF in attribute selector")
+	}
+	var val string
+	var rx *regexp.Regexp
+	if op == "#=" {
+		rx, err = p.parseRegex()
+	} else {
+		switch p.s[p.i] {
+		case '\'', '"':
+			val, err = p.parseString()
+		default:
+			val, err = p.parseIdentifier()
+		}
+	}
+	if err != nil {
+		return attrSelector{}, err
+	}
+
+	p.skipWhitespace()
+	if p.i >= len(p.s) {
+		return attrSelector{}, errors.New("unexpected EOF in attribute selector")
+	}
+	if p.s[p.i] != ']' {
+		return attrSelector{}, fmt.Errorf("expected ']', found '%c' instead", p.s[p.i])
+	}
+	p.i++
+
+	switch op {
+	case "=", "!=", "~=", "|=", "^=", "$=", "*=", "#=":
+		return attrSelector{key: key, val: val, operation: op, regexp: rx}, nil
+	default:
+		return attrSelector{}, fmt.Errorf("attribute operator %q is not supported", op)
+	}
+}
+
+var errExpectedParenthesis = errors.New("expected '(' but didn't find it")
+var errExpectedClosingParenthesis = errors.New("expected ')' but didn't find it")
+var errUnmatchedParenthesis = errors.New("unmatched '('")
+
+// parsePseudoclassSelector parses a pseudoclass selector like :not(p)
+func (p *parser) parsePseudoclassSelector() (out Sel, err error) {
+	if p.i >= len(p.s) {
+		return nil, fmt.Errorf("expected pseudoclass selector (:pseudoclass), found EOF instead")
+	}
+	if p.s[p.i] != ':' {
+		return nil, fmt.Errorf("expected attribute selector (:pseudoclass), found '%c' instead", p.s[p.i])
+	}
+
+	p.i++
+	if p.s[p.i] == ':' { // we found a pseudo-element
+		p.i++
+	}
+
+	name, err := p.parseIdentifier()
+	if err != nil {
+		return
+	}
+	name = toLowerASCII(name)
+	switch name {
+	case "not", "has", "haschild":
+		if !p.consumeParenthesis() {
+			return out, errExpectedParenthesis
+		}
+		sel, parseErr := p.parseSelectorGroup()
+		if parseErr != nil {
+			return out, parseErr
+		}
+		if !p.consumeClosingParenthesis() {
+			return out, errExpectedClosingParenthesis
+		}
+
+		out = relativePseudoClassSelector{name: name, match: sel}
+
+	case "contains", "containsown":
+		if !p.consumeParenthesis() {
+			return out, errExpectedParenthesis
+		}
+		if p.i == len(p.s) {
+			return out, errUnmatchedParenthesis
+		}
+		var val string
+		switch p.s[p.i] {
+		case '\'', '"':
+			val, err = p.parseString()
+		default:
+			val, err = p.parseIdentifier()
+		}
+		if err != nil {
+			return out, err
+		}
+		val = strings.ToLower(val)
+		p.skipWhitespace()
+		if p.i >= len(p.s) {
+			return out, errors.New("unexpected EOF in pseudo selector")
+		}
+		if !p.consumeClosingParenthesis() {
+			return out, errExpectedClosingParenthesis
+		}
+
+		out = containsPseudoClassSelector{own: name == "containsown", value: val}
+
+	case "matches", "matchesown":
+		if !p.consumeParenthesis() {
+			return out, errExpectedParenthesis
+		}
+		rx, err := p.parseRegex()
+		if err != nil {
+			return out, err
+		}
+		if p.i >= len(p.s) {
+			return out, errors.New("unexpected EOF in pseudo selector")
+		}
+		if !p.consumeClosingParenthesis() {
+			return out, errExpectedClosingParenthesis
+		}
+
+		out = regexpPseudoClassSelector{own: name == "matchesown", regexp: rx}
+
+	case "nth-child", "nth-last-child", "nth-of-type", "nth-last-of-type":
+		if !p.consumeParenthesis() {
+			return out, errExpectedParenthesis
+		}
+		a, b, err := p.parseNth()
+		if err != nil {
+			return out, err
+		}
+		if !p.consumeClosingParenthesis() {
+			return out, errExpectedClosingParenthesis
+		}
+		last := name == "nth-last-child" || name == "nth-last-of-type"
+		ofType := name == "nth-of-type" || name == "nth-last-of-type"
+		out = nthPseudoClassSelector{a: a, b: b, last: last, ofType: ofType}
+
+	case "first-child":
+		out = nthPseudoClassSelector{a: 0, b: 1, ofType: false, last: false}
+	case "last-child":
+		out = nthPseudoClassSelector{a: 0, b: 1, ofType: false, last: true}
+	case "first-of-type":
+		out = nthPseudoClassSelector{a: 0, b: 1, ofType: true, last: false}
+	case "last-of-type":
+		out = nthPseudoClassSelector{a: 0, b: 1, ofType: true, last: true}
+	case "only-child":
+		out = onlyChildPseudoClassSelector{ofType: false}
+	case "only-of-type":
+		out = onlyChildPseudoClassSelector{ofType: true}
+	case "input":
+		out = inputPseudoClassSelector{}
+	case "empty":
+		out = emptyElementPseudoClassSelector{}
+	case "root":
+		out = rootPseudoClassSelector{}
+	case "after", "backdrop", "before", "cue", "first-letter", "first-line", "grammar-error", "marker", "placeholder", "selection", "spelling-error":
+		return out, errors.New("pseudo-elements are not yet supported")
+	default:
+		return out, fmt.Errorf("unknown pseudoclass or pseudoelement :%s", name)
+	}
+	return
+}
+
+// parseInteger parses a  decimal integer.
+func (p *parser) parseInteger() (int, error) {
+	i := p.i
+	start := i
+	for i < len(p.s) && '0' <= p.s[i] && p.s[i] <= '9' {
+		i++
+	}
+	if i == start {
+		return 0, errors.New("expected integer, but didn't find it")
+	}
+	p.i = i
+
+	val, err := strconv.Atoi(p.s[start:i])
+	if err != nil {
+		return 0, err
+	}
+
+	return val, nil
+}
+
+// parseNth parses the argument for :nth-child (normally of the form an+b).
+func (p *parser) parseNth() (a, b int, err error) {
+	// initial state
+	if p.i >= len(p.s) {
+		goto eof
+	}
+	switch p.s[p.i] {
+	case '-':
+		p.i++
+		goto negativeA
+	case '+':
+		p.i++
+		goto positiveA
+	case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
+		goto positiveA
+	case 'n', 'N':
+		a = 1
+		p.i++
+		goto readN
+	case 'o', 'O', 'e', 'E':
+		id, nameErr := p.parseName()
+		if nameErr != nil {
+			return 0, 0, nameErr
+		}
+		id = toLowerASCII(id)
+		if id == "odd" {
+			return 2, 1, nil
+		}
+		if id == "even" {
+			return 2, 0, nil
+		}
+		return 0, 0, fmt.Errorf("expected 'odd' or 'even', but found '%s' instead", id)
+	default:
+		goto invalid
+	}
+
+positiveA:
+	if p.i >= len(p.s) {
+		goto eof
+	}
+	switch p.s[p.i] {
+	case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
+		a, err = p.parseInteger()
+		if err != nil {
+			return 0, 0, err
+		}
+		goto readA
+	case 'n', 'N':
+		a = 1
+		p.i++
+		goto readN
+	default:
+		goto invalid
+	}
+
+negativeA:
+	if p.i >= len(p.s) {
+		goto eof
+	}
+	switch p.s[p.i] {
+	case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
+		a, err = p.parseInteger()
+		if err != nil {
+			return 0, 0, err
+		}
+		a = -a
+		goto readA
+	case 'n', 'N':
+		a = -1
+		p.i++
+		goto readN
+	default:
+		goto invalid
+	}
+
+readA:
+	if p.i >= len(p.s) {
+		goto eof
+	}
+	switch p.s[p.i] {
+	case 'n', 'N':
+		p.i++
+		goto readN
+	default:
+		// The number we read as a is actually b.
+		return 0, a, nil
+	}
+
+readN:
+	p.skipWhitespace()
+	if p.i >= len(p.s) {
+		goto eof
+	}
+	switch p.s[p.i] {
+	case '+':
+		p.i++
+		p.skipWhitespace()
+		b, err = p.parseInteger()
+		if err != nil {
+			return 0, 0, err
+		}
+		return a, b, nil
+	case '-':
+		p.i++
+		p.skipWhitespace()
+		b, err = p.parseInteger()
+		if err != nil {
+			return 0, 0, err
+		}
+		return a, -b, nil
+	default:
+		return a, 0, nil
+	}
+
+eof:
+	return 0, 0, errors.New("unexpected EOF while attempting to parse expression of form an+b")
+
+invalid:
+	return 0, 0, errors.New("unexpected character while attempting to parse expression of form an+b")
+}
+
+// parseSimpleSelectorSequence parses a selector sequence that applies to
+// a single element.
+func (p *parser) parseSimpleSelectorSequence() (Sel, error) {
+	var selectors []Sel
+
+	if p.i >= len(p.s) {
+		return nil, errors.New("expected selector, found EOF instead")
+	}
+
+	switch p.s[p.i] {
+	case '*':
+		// It's the universal selector. Just skip over it, since it doesn't affect the meaning.
+		p.i++
+	case '#', '.', '[', ':':
+		// There's no type selector. Wait to process the other till the main loop.
+	default:
+		r, err := p.parseTypeSelector()
+		if err != nil {
+			return nil, err
+		}
+		selectors = append(selectors, r)
+	}
+
+loop:
+	for p.i < len(p.s) {
+		var (
+			ns  Sel
+			err error
+		)
+		switch p.s[p.i] {
+		case '#':
+			ns, err = p.parseIDSelector()
+		case '.':
+			ns, err = p.parseClassSelector()
+		case '[':
+			ns, err = p.parseAttributeSelector()
+		case ':':
+			ns, err = p.parsePseudoclassSelector()
+		default:
+			break loop
+		}
+		if err != nil {
+			return nil, err
+		}
+
+		selectors = append(selectors, ns)
+	}
+	if len(selectors) == 1 { // no need wrap the selectors in compoundSelector
+		return selectors[0], nil
+	}
+	return compoundSelector{selectors: selectors}, nil
+}
+
+// parseSelector parses a selector that may include combinators.
+func (p *parser) parseSelector() (Sel, error) {
+	p.skipWhitespace()
+	result, err := p.parseSimpleSelectorSequence()
+	if err != nil {
+		return nil, err
+	}
+
+	for {
+		var (
+			combinator byte
+			c          Sel
+		)
+		if p.skipWhitespace() {
+			combinator = ' '
+		}
+		if p.i >= len(p.s) {
+			return result, nil
+		}
+
+		switch p.s[p.i] {
+		case '+', '>', '~':
+			combinator = p.s[p.i]
+			p.i++
+			p.skipWhitespace()
+		case ',', ')':
+			// These characters can't begin a selector, but they can legally occur after one.
+			return result, nil
+		}
+
+		if combinator == 0 {
+			return result, nil
+		}
+
+		c, err = p.parseSimpleSelectorSequence()
+		if err != nil {
+			return nil, err
+		}
+		result = combinedSelector{first: result, combinator: combinator, second: c}
+	}
+}
+
+// parseSelectorGroup parses a group of selectors, separated by commas.
+func (p *parser) parseSelectorGroup() (SelectorGroup, error) {
+	current, err := p.parseSelector()
+	if err != nil {
+		return nil, err
+	}
+	result := SelectorGroup{current}
+
+	for p.i < len(p.s) {
+		if p.s[p.i] != ',' {
+			break
+		}
+		p.i++
+		c, err := p.parseSelector()
+		if err != nil {
+			return nil, err
+		}
+		result = append(result, c)
+	}
+	return result, nil
+}

vendor/github.com/andybalholm/cascadia/selector.go

@@ -0,0 +1,833 @@
+package cascadia
+
+import (
+	"bytes"
+	"fmt"
+	"regexp"
+	"strings"
+
+	"golang.org/x/net/html"
+)
+
+// Matcher is the interface for basic selector functionality.
+// Match returns whether a selector matches n.
+type Matcher interface {
+	Match(n *html.Node) bool
+}
+
+// Sel is the interface for all the functionality provided by selectors.
+// It is currently the same as Matcher, but other methods may be added in the
+// future.
+type Sel interface {
+	Matcher
+	Specificity() Specificity
+}
+
+// Parse parses a selector.
+func Parse(sel string) (Sel, error) {
+	p := &parser{s: sel}
+	compiled, err := p.parseSelector()
+	if err != nil {
+		return nil, err
+	}
+
+	if p.i < len(sel) {
+		return nil, fmt.Errorf("parsing %q: %d bytes left over", sel, len(sel)-p.i)
+	}
+
+	return compiled, nil
+}
+
+// ParseGroup parses a selector, or a group of selectors separated by commas.
+func ParseGroup(sel string) (SelectorGroup, error) {
+	p := &parser{s: sel}
+	compiled, err := p.parseSelectorGroup()
+	if err != nil {
+		return nil, err
+	}
+
+	if p.i < len(sel) {
+		return nil, fmt.Errorf("parsing %q: %d bytes left over", sel, len(sel)-p.i)
+	}
+
+	return compiled, nil
+}
+
+// A Selector is a function which tells whether a node matches or not.
+//
+// This type is maintained for compatibility; I recommend using the newer and
+// more idiomatic interfaces Sel and Matcher.
+type Selector func(*html.Node) bool
+
+// Compile parses a selector and returns, if successful, a Selector object
+// that can be used to match against html.Node objects.
+func Compile(sel string) (Selector, error) {
+	compiled, err := ParseGroup(sel)
+	if err != nil {
+		return nil, err
+	}
+
+	return Selector(compiled.Match), nil
+}
+
+// MustCompile is like Compile, but panics instead of returning an error.
+func MustCompile(sel string) Selector {
+	compiled, err := Compile(sel)
+	if err != nil {
+		panic(err)
+	}
+	return compiled
+}
+
+// MatchAll returns a slice of the nodes that match the selector,
+// from n and its children.
+func (s Selector) MatchAll(n *html.Node) []*html.Node {
+	return s.matchAllInto(n, nil)
+}
+
+func (s Selector) matchAllInto(n *html.Node, storage []*html.Node) []*html.Node {
+	if s(n) {
+		storage = append(storage, n)
+	}
+
+	for child := n.FirstChild; child != nil; child = child.NextSibling {
+		storage = s.matchAllInto(child, storage)
+	}
+
+	return storage
+}
+
+func queryInto(n *html.Node, m Matcher, storage []*html.Node) []*html.Node {
+	for child := n.FirstChild; child != nil; child = child.NextSibling {
+		if m.Match(child) {
+			storage = append(storage, child)
+		}
+		storage = queryInto(child, m, storage)
+	}
+
+	return storage
+}
+
+// QueryAll returns a slice of all the nodes that match m, from the descendants
+// of n.
+func QueryAll(n *html.Node, m Matcher) []*html.Node {
+	return queryInto(n, m, nil)
+}
+
+// Match returns true if the node matches the selector.
+func (s Selector) Match(n *html.Node) bool {
+	return s(n)
+}
+
+// MatchFirst returns the first node that matches s, from n and its children.
+func (s Selector) MatchFirst(n *html.Node) *html.Node {
+	if s.Match(n) {
+		return n
+	}
+
+	for c := n.FirstChild; c != nil; c = c.NextSibling {
+		m := s.MatchFirst(c)
+		if m != nil {
+			return m
+		}
+	}
+	return nil
+}
+
+// Query returns the first node that matches m, from the descendants of n.
+// If none matches, it returns nil.
+func Query(n *html.Node, m Matcher) *html.Node {
+	for c := n.FirstChild; c != nil; c = c.NextSibling {
+		if m.Match(c) {
+			return c
+		}
+		if matched := Query(c, m); matched != nil {
+			return matched
+		}
+	}
+
+	return nil
+}
+
+// Filter returns the nodes in nodes that match the selector.
+func (s Selector) Filter(nodes []*html.Node) (result []*html.Node) {
+	for _, n := range nodes {
+		if s(n) {
+			result = append(result, n)
+		}
+	}
+	return result
+}
+
+// Filter returns the nodes that match m.
+func Filter(nodes []*html.Node, m Matcher) (result []*html.Node) {
+	for _, n := range nodes {
+		if m.Match(n) {
+			result = append(result, n)
+		}
+	}
+	return result
+}
+
+type tagSelector struct {
+	tag string
+}
+
+// Matches elements with a given tag name.
+func (t tagSelector) Match(n *html.Node) bool {
+	return n.Type == html.ElementNode && n.Data == t.tag
+}
+
+func (c tagSelector) Specificity() Specificity {
+	return Specificity{0, 0, 1}
+}
+
+type classSelector struct {
+	class string
+}
+
+// Matches elements by class attribute.
+func (t classSelector) Match(n *html.Node) bool {
+	return matchAttribute(n, "class", func(s string) bool {
+		return matchInclude(t.class, s)
+	})
+}
+
+func (c classSelector) Specificity() Specificity {
+	return Specificity{0, 1, 0}
+}
+
+type idSelector struct {
+	id string
+}
+
+// Matches elements by id attribute.
+func (t idSelector) Match(n *html.Node) bool {
+	return matchAttribute(n, "id", func(s string) bool {
+		return s == t.id
+	})
+}
+
+func (c idSelector) Specificity() Specificity {
+	return Specificity{1, 0, 0}
+}
+
+type attrSelector struct {
+	key, val, operation string
+	regexp              *regexp.Regexp
+}
+
+// Matches elements by attribute value.
+func (t attrSelector) Match(n *html.Node) bool {
+	switch t.operation {
+	case "":
+		return matchAttribute(n, t.key, func(string) bool { return true })
+	case "=":
+		return matchAttribute(n, t.key, func(s string) bool { return s == t.val })
+	case "!=":
+		return attributeNotEqualMatch(t.key, t.val, n)
+	case "~=":
+		// matches elements where the attribute named key is a whitespace-separated list that includes val.
+		return matchAttribute(n, t.key, func(s string) bool { return matchInclude(t.val, s) })
+	case "|=":
+		return attributeDashMatch(t.key, t.val, n)
+	case "^=":
+		return attributePrefixMatch(t.key, t.val, n)
+	case "$=":
+		return attributeSuffixMatch(t.key, t.val, n)
+	case "*=":
+		return attributeSubstringMatch(t.key, t.val, n)
+	case "#=":
+		return attributeRegexMatch(t.key, t.regexp, n)
+	default:
+		panic(fmt.Sprintf("unsuported operation : %s", t.operation))
+	}
+}
+
+// matches elements where the attribute named key satisifes the function f.
+func matchAttribute(n *html.Node, key string, f func(string) bool) bool {
+	if n.Type != html.ElementNode {
+		return false
+	}
+	for _, a := range n.Attr {
+		if a.Key == key && f(a.Val) {
+			return true
+		}
+	}
+	return false
+}
+
+// attributeNotEqualMatch matches elements where
+// the attribute named key does not have the value val.
+func attributeNotEqualMatch(key, val string, n *html.Node) bool {
+	if n.Type != html.ElementNode {
+		return false
+	}
+	for _, a := range n.Attr {
+		if a.Key == key && a.Val == val {
+			return false
+		}
+	}
+	return true
+}
+
+// returns true if s is a whitespace-separated list that includes val.
+func matchInclude(val, s string) bool {
+	for s != "" {
+		i := strings.IndexAny(s, " \t\r\n\f")
+		if i == -1 {
+			return s == val
+		}
+		if s[:i] == val {
+			return true
+		}
+		s = s[i+1:]
+	}
+	return false
+}
+
+//  matches elements where the attribute named key equals val or starts with val plus a hyphen.
+func attributeDashMatch(key, val string, n *html.Node) bool {
+	return matchAttribute(n, key,
+		func(s string) bool {
+			if s == val {
+				return true
+			}
+			if len(s) <= len(val) {
+				return false
+			}
+			if s[:len(val)] == val && s[len(val)] == '-' {
+				return true
+			}
+			return false
+		})
+}
+
+// attributePrefixMatch returns a Selector that matches elements where
+// the attribute named key starts with val.
+func attributePrefixMatch(key, val string, n *html.Node) bool {
+	return matchAttribute(n, key,
+		func(s string) bool {
+			if strings.TrimSpace(s) == "" {
+				return false
+			}
+			return strings.HasPrefix(s, val)
+		})
+}
+
+// attributeSuffixMatch matches elements where
+// the attribute named key ends with val.
+func attributeSuffixMatch(key, val string, n *html.Node) bool {
+	return matchAttribute(n, key,
+		func(s string) bool {
+			if strings.TrimSpace(s) == "" {
+				return false
+			}
+			return strings.HasSuffix(s, val)
+		})
+}
+
+// attributeSubstringMatch matches nodes where
+// the attribute named key contains val.
+func attributeSubstringMatch(key, val string, n *html.Node) bool {
+	return matchAttribute(n, key,
+		func(s string) bool {
+			if strings.TrimSpace(s) == "" {
+				return false
+			}
+			return strings.Contains(s, val)
+		})
+}
+
+// attributeRegexMatch  matches nodes where
+// the attribute named key matches the regular expression rx
+func attributeRegexMatch(key string, rx *regexp.Regexp, n *html.Node) bool {
+	return matchAttribute(n, key,
+		func(s string) bool {
+			return rx.MatchString(s)
+		})
+}
+
+func (c attrSelector) Specificity() Specificity {
+	return Specificity{0, 1, 0}
+}
+
+// ---------------- Pseudo class selectors ----------------
+// we use severals concrete types of pseudo-class selectors
+
+type relativePseudoClassSelector struct {
+	name  string // one of "not", "has", "haschild"
+	match SelectorGroup
+}
+
+func (s relativePseudoClassSelector) Match(n *html.Node) bool {
+	if n.Type != html.ElementNode {
+		return false
+	}
+	switch s.name {
+	case "not":
+		// matches elements that do not match a.
+		return !s.match.Match(n)
+	case "has":
+		//  matches elements with any descendant that matches a.
+		return hasDescendantMatch(n, s.match)
+	case "haschild":
+		// matches elements with a child that matches a.
+		return hasChildMatch(n, s.match)
+	default:
+		panic(fmt.Sprintf("unsupported relative pseudo class selector : %s", s.name))
+	}
+}
+
+// hasChildMatch returns whether n has any child that matches a.
+func hasChildMatch(n *html.Node, a Matcher) bool {
+	for c := n.FirstChild; c != nil; c = c.NextSibling {
+		if a.Match(c) {
+			return true
+		}
+	}
+	return false
+}
+
+// hasDescendantMatch performs a depth-first search of n's descendants,
+// testing whether any of them match a. It returns true as soon as a match is
+// found, or false if no match is found.
+func hasDescendantMatch(n *html.Node, a Matcher) bool {
+	for c := n.FirstChild; c != nil; c = c.NextSibling {
+		if a.Match(c) || (c.Type == html.ElementNode && hasDescendantMatch(c, a)) {
+			return true
+		}
+	}
+	return false
+}
+
+// Specificity returns the specificity of the most specific selectors
+// in the pseudo-class arguments.
+// See https://www.w3.org/TR/selectors/#specificity-rules
+func (s relativePseudoClassSelector) Specificity() Specificity {
+	var max Specificity
+	for _, sel := range s.match {
+		newSpe := sel.Specificity()
+		if max.Less(newSpe) {
+			max = newSpe
+		}
+	}
+	return max
+}
+
+type containsPseudoClassSelector struct {
+	own   bool
+	value string
+}
+
+func (s containsPseudoClassSelector) Match(n *html.Node) bool {
+	var text string
+	if s.own {
+		// matches nodes that directly contain the given text
+		text = strings.ToLower(nodeOwnText(n))
+	} else {
+		// matches nodes that contain the given text.
+		text = strings.ToLower(nodeText(n))
+	}
+	return strings.Contains(text, s.value)
+}
+
+func (s containsPseudoClassSelector) Specificity() Specificity {
+	return Specificity{0, 1, 0}
+}
+
+type regexpPseudoClassSelector struct {
+	own    bool
+	regexp *regexp.Regexp
+}
+
+func (s regexpPseudoClassSelector) Match(n *html.Node) bool {
+	var text string
+	if s.own {
+		// matches nodes whose text directly matches the specified regular expression
+		text = nodeOwnText(n)
+	} else {
+		// matches nodes whose text matches the specified regular expression
+		text = nodeText(n)
+	}
+	return s.regexp.MatchString(text)
+}
+
+// writeNodeText writes the text contained in n and its descendants to b.
+func writeNodeText(n *html.Node, b *bytes.Buffer) {
+	switch n.Type {
+	case html.TextNode:
+		b.WriteString(n.Data)
+	case html.ElementNode:
+		for c := n.FirstChild; c != nil; c = c.NextSibling {
+			writeNodeText(c, b)
+		}
+	}
+}
+
+// nodeText returns the text contained in n and its descendants.
+func nodeText(n *html.Node) string {
+	var b bytes.Buffer
+	writeNodeText(n, &b)
+	return b.String()
+}
+
+// nodeOwnText returns the contents of the text nodes that are direct
+// children of n.
+func nodeOwnText(n *html.Node) string {
+	var b bytes.Buffer
+	for c := n.FirstChild; c != nil; c = c.NextSibling {
+		if c.Type == html.TextNode {
+			b.WriteString(c.Data)
+		}
+	}
+	return b.String()
+}
+
+func (s regexpPseudoClassSelector) Specificity() Specificity {
+	return Specificity{0, 1, 0}
+}
+
+type nthPseudoClassSelector struct {
+	a, b         int
+	last, ofType bool
+}
+
+func (s nthPseudoClassSelector) Match(n *html.Node) bool {
+	if s.a == 0 {
+		if s.last {
+			return simpleNthLastChildMatch(s.b, s.ofType, n)
+		} else {
+			return simpleNthChildMatch(s.b, s.ofType, n)
+		}
+	}
+	return nthChildMatch(s.a, s.b, s.last, s.ofType, n)
+}
+
+// nthChildMatch implements :nth-child(an+b).
+// If last is true, implements :nth-last-child instead.
+// If ofType is true, implements :nth-of-type instead.
+func nthChildMatch(a, b int, last, ofType bool, n *html.Node) bool {
+	if n.Type != html.ElementNode {
+		return false
+	}
+
+	parent := n.Parent
+	if parent == nil {
+		return false
+	}
+
+	if parent.Type == html.DocumentNode {
+		return false
+	}
+
+	i := -1
+	count := 0
+	for c := parent.FirstChild; c != nil; c = c.NextSibling {
+		if (c.Type != html.ElementNode) || (ofType && c.Data != n.Data) {
+			continue
+		}
+		count++
+		if c == n {
+			i = count
+			if !last {
+				break
+			}
+		}
+	}
+
+	if i == -1 {
+		// This shouldn't happen, since n should always be one of its parent's children.
+		return false
+	}
+
+	if last {
+		i = count - i + 1
+	}
+
+	i -= b
+	if a == 0 {
+		return i == 0
+	}
+
+	return i%a == 0 && i/a >= 0
+}
+
+// simpleNthChildMatch implements :nth-child(b).
+// If ofType is true, implements :nth-of-type instead.
+func simpleNthChildMatch(b int, ofType bool, n *html.Node) bool {
+	if n.Type != html.ElementNode {
+		return false
+	}
+
+	parent := n.Parent
+	if parent == nil {
+		return false
+	}
+
+	if parent.Type == html.DocumentNode {
+		return false
+	}
+
+	count := 0
+	for c := parent.FirstChild; c != nil; c = c.NextSibling {
+		if c.Type != html.ElementNode || (ofType && c.Data != n.Data) {
+			continue
+		}
+		count++
+		if c == n {
+			return count == b
+		}
+		if count >= b {
+			return false
+		}
+	}
+	return false
+}
+
+// simpleNthLastChildMatch implements :nth-last-child(b).
+// If ofType is true, implements :nth-last-of-type instead.
+func simpleNthLastChildMatch(b int, ofType bool, n *html.Node) bool {
+	if n.Type != html.ElementNode {
+		return false
+	}
+
+	parent := n.Parent
+	if parent == nil {
+		return false
+	}
+
+	if parent.Type == html.DocumentNode {
+		return false
+	}
+
+	count := 0
+	for c := parent.LastChild; c != nil; c = c.PrevSibling {
+		if c.Type != html.ElementNode || (ofType && c.Data != n.Data) {
+			continue
+		}
+		count++
+		if c == n {
+			return count == b
+		}
+		if count >= b {
+			return false
+		}
+	}
+	return false
+}
+
+// Specificity for nth-child pseudo-class.
+// Does not support a list of selectors
+func (s nthPseudoClassSelector) Specificity() Specificity {
+	return Specificity{0, 1, 0}
+}
+
+type onlyChildPseudoClassSelector struct {
+	ofType bool
+}
+
+// Match implements :only-child.
+// If `ofType` is true, it implements :only-of-type instead.
+func (s onlyChildPseudoClassSelector) Match(n *html.Node) bool {
+	if n.Type != html.ElementNode {
+		return false
+	}
+
+	parent := n.Parent
+	if parent == nil {
+		return false
+	}
+
+	if parent.Type == html.DocumentNode {
+		return false
+	}
+
+	count := 0
+	for c := parent.FirstChild; c != nil; c = c.NextSibling {
+		if (c.Type != html.ElementNode) || (s.ofType && c.Data != n.Data) {
+			continue
+		}
+		count++
+		if count > 1 {
+			return false
+		}
+	}
+
+	return count == 1
+}
+
+func (s onlyChildPseudoClassSelector) Specificity() Specificity {
+	return Specificity{0, 1, 0}
+}
+
+type inputPseudoClassSelector struct{}
+
+// Matches input, select, textarea and button elements.
+func (s inputPseudoClassSelector) Match(n *html.Node) bool {
+	return n.Type == html.ElementNode && (n.Data == "input" || n.Data == "select" || n.Data == "textarea" || n.Data == "button")
+}
+
+func (s inputPseudoClassSelector) Specificity() Specificity {
+	return Specificity{0, 1, 0}
+}
+
+type emptyElementPseudoClassSelector struct{}
+
+// Matches empty elements.
+func (s emptyElementPseudoClassSelector) Match(n *html.Node) bool {
+	if n.Type != html.ElementNode {
+		return false
+	}
+
+	for c := n.FirstChild; c != nil; c = c.NextSibling {
+		switch c.Type {
+		case html.ElementNode, html.TextNode:
+			return false
+		}
+	}
+
+	return true
+}
+
+func (s emptyElementPseudoClassSelector) Specificity() Specificity {
+	return Specificity{0, 1, 0}
+}
+
+type rootPseudoClassSelector struct{}
+
+// Match implements :root
+func (s rootPseudoClassSelector) Match(n *html.Node) bool {
+	if n.Type != html.ElementNode {
+		return false
+	}
+	if n.Parent == nil {
+		return false
+	}
+	return n.Parent.Type == html.DocumentNode
+}
+
+func (s rootPseudoClassSelector) Specificity() Specificity {
+	return Specificity{0, 1, 0}
+}
+
+type compoundSelector struct {
+	selectors []Sel
+}
+
+// Matches elements if each sub-selectors matches.
+func (t compoundSelector) Match(n *html.Node) bool {
+	if len(t.selectors) == 0 {
+		return n.Type == html.ElementNode
+	}
+
+	for _, sel := range t.selectors {
+		if !sel.Match(n) {
+			return false
+		}
+	}
+	return true
+}
+
+func (s compoundSelector) Specificity() Specificity {
+	var out Specificity
+	for _, sel := range s.selectors {
+		out = out.Add(sel.Specificity())
+	}
+	return out
+}
+
+type combinedSelector struct {
+	first      Sel
+	combinator byte
+	second     Sel
+}
+
+func (t combinedSelector) Match(n *html.Node) bool {
+	if t.first == nil {
+		return false // maybe we should panic
+	}
+	switch t.combinator {
+	case 0:
+		return t.first.Match(n)
+	case ' ':
+		return descendantMatch(t.first, t.second, n)
+	case '>':
+		return childMatch(t.first, t.second, n)
+	case '+':
+		return siblingMatch(t.first, t.second, true, n)
+	case '~':
+		return siblingMatch(t.first, t.second, false, n)
+	default:
+		panic("unknown combinator")
+	}
+}
+
+// matches an element if it matches d and has an ancestor that matches a.
+func descendantMatch(a, d Matcher, n *html.Node) bool {
+	if !d.Match(n) {
+		return false
+	}
+
+	for p := n.Parent; p != nil; p = p.Parent {
+		if a.Match(p) {
+			return true
+		}
+	}
+
+	return false
+}
+
+// matches an element if it matches d and its parent matches a.
+func childMatch(a, d Matcher, n *html.Node) bool {
+	return d.Match(n) && n.Parent != nil && a.Match(n.Parent)
+}
+
+// matches an element if it matches s2 and is preceded by an element that matches s1.
+// If adjacent is true, the sibling must be immediately before the element.
+func siblingMatch(s1, s2 Matcher, adjacent bool, n *html.Node) bool {
+	if !s2.Match(n) {
+		return false
+	}
+
+	if adjacent {
+		for n = n.PrevSibling; n != nil; n = n.PrevSibling {
+			if n.Type == html.TextNode || n.Type == html.CommentNode {
+				continue
+			}
+			return s1.Match(n)
+		}
+		return false
+	}
+
+	// Walk backwards looking for element that matches s1
+	for c := n.PrevSibling; c != nil; c = c.PrevSibling {
+		if s1.Match(c) {
+			return true
+		}
+	}
+
+	return false
+}
+
+func (s combinedSelector) Specificity() Specificity {
+	spec := s.first.Specificity()
+	if s.second != nil {
+		spec = spec.Add(s.second.Specificity())
+	}
+	return spec
+}
+
+// A SelectorGroup is a list of selectors, which matches if any of the
+// individual selectors matches.
+type SelectorGroup []Sel
+
+// Match returns true if the node matches one of the single selectors.
+func (s SelectorGroup) Match(n *html.Node) bool {
+	for _, sel := range s {
+		if sel.Match(n) {
+			return true
+		}
+	}
+	return false
+}

vendor/github.com/andybalholm/cascadia/specificity.go

@@ -0,0 +1,26 @@
+package cascadia
+
+// Specificity is the CSS specificity as defined in
+// https://www.w3.org/TR/selectors/#specificity-rules
+// with the convention Specificity = [A,B,C].
+type Specificity [3]int
+
+// returns `true` if s < other (strictly), false otherwise
+func (s Specificity) Less(other Specificity) bool {
+	for i := range s {
+		if s[i] < other[i] {
+			return true
+		}
+		if s[i] > other[i] {
+			return false
+		}
+	}
+	return false
+}
+
+func (s Specificity) Add(other Specificity) Specificity {
+	for i, sp := range other {
+		s[i] += sp
+	}
+	return s
+}

vendor/github.com/antchfx/htmlquery/.gitignore

@@ -0,0 +1,32 @@
+# vscode
+.vscode
+debug
+*.test
+
+./build
+
+# Compiled Object files, Static and Dynamic libs (Shared Objects)
+*.o
+*.a
+*.so
+
+
+# Folders
+_obj
+_test
+
+# Architecture specific extensions/prefixes
+*.[568vq]
+[568vq].out
+
+*.cgo1.go
+*.cgo2.c
+_cgo_defun.c
+_cgo_gotypes.go
+_cgo_export.*
+
+_testmain.go
+
+*.exe
+*.test
+*.prof

vendor/github.com/antchfx/htmlquery/.travis.yml

@@ -0,0 +1,16 @@
+language: go
+
+go:
+  - 1.9.x
+  - 1.12.x
+  - 1.13.x
+
+install:
+  - go get golang.org/x/net/html/charset
+  - go get golang.org/x/net/html
+  - go get github.com/antchfx/xpath
+  - go get github.com/mattn/goveralls
+  - go get github.com/golang/groupcache
+
+script:
+  - $HOME/gopath/bin/goveralls -service=travis-ci

vendor/github.com/antchfx/htmlquery/LICENSE

@@ -0,0 +1,17 @@
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

vendor/github.com/antchfx/htmlquery/README.md

@@ -0,0 +1,168 @@
+htmlquery
+====
+[![Build Status](https://travis-ci.org/antchfx/htmlquery.svg?branch=master)](https://travis-ci.org/antchfx/htmlquery)
+[![Coverage Status](https://coveralls.io/repos/github/antchfx/htmlquery/badge.svg?branch=master)](https://coveralls.io/github/antchfx/htmlquery?branch=master)
+[![GoDoc](https://godoc.org/github.com/antchfx/htmlquery?status.svg)](https://godoc.org/github.com/antchfx/htmlquery)
+[![Go Report Card](https://goreportcard.com/badge/github.com/antchfx/htmlquery)](https://goreportcard.com/report/github.com/antchfx/htmlquery)
+
+Overview
+====
+
+`htmlquery` is an XPath query package for HTML, lets you extract data or evaluate from HTML documents by an XPath expression.
+
+`htmlquery` built-in the query object caching feature based on [LRU](https://godoc.org/github.com/golang/groupcache/lru), this feature will caching the recently used XPATH query string. Enable query caching can avoid re-compile XPath expression each query. 
+
+Installation
+====
+
+```
+go get github.com/antchfx/htmlquery
+```
+
+Getting Started
+====
+
+#### Query, returns matched elements or error.
+
+```go
+nodes, err := htmlquery.QueryAll(doc, "//a")
+if err != nil {
+	panic(`not a valid XPath expression.`)
+}
+```
+
+#### Load HTML document from URL.
+
+```go
+doc, err := htmlquery.LoadURL("http://example.com/")
+```
+
+#### Load HTML from document.
+
+```go
+filePath := "/home/user/sample.html"
+doc, err := htmlquery.LoadDoc(filePath)
+```
+
+#### Load HTML document from string.
+
+```go
+s := `<html>....</html>`
+doc, err := htmlquery.Parse(strings.NewReader(s))
+```
+
+#### Find all A elements.
+
+```go
+list := htmlquery.Find(doc, "//a")
+```
+
+#### Find all A elements that have `href` attribute.
+
+```go
+list := range htmlquery.Find(doc, "//a[@href]")	
+```
+
+#### Find all A elements with `href` attribute and only return `href` value.
+
+```go
+list := range htmlquery.Find(doc, "//a/@href")	
+for n := range list{
+	fmt.Println(htmlquery.InnerText(n)) // output @href value without A element.
+}
+```
+
+### Find the third A element.
+
+```go
+a := htmlquery.FindOne(doc, "//a[3]")
+```
+
+#### Evaluate the number of all IMG element.
+
+```go
+expr, _ := xpath.Compile("count(//img)")
+v := expr.Evaluate(htmlquery.CreateXPathNavigator(doc)).(float64)
+fmt.Printf("total count is %f", v)
+```
+
+
+FAQ
+====
+
+#### `Find()` vs `QueryAll()`, which is better?
+
+`Find` and `QueryAll` both do the same things, searches all of matched html nodes.
+The `Find` will panics if you give an error XPath query, but `QueryAll` will return an error for you.
+
+#### Can I save my query expression object for the next query?
+
+Yes, you can. We offer the `QuerySelector` and `QuerySelectorAll` methods, It will accept your query expression object.
+
+Cache a query expression object(or reused) will avoid re-compile XPath query expression, improve your query performance.
+
+#### XPath query object cache performance
+
+```
+goos: windows
+goarch: amd64
+pkg: github.com/antchfx/htmlquery
+BenchmarkSelectorCache-4                20000000                55.2 ns/op
+BenchmarkDisableSelectorCache-4           500000              3162 ns/op
+```
+
+#### How to disable caching?
+
+```
+htmlquery.DisableSelectorCache = true
+```
+
+Changelogs
+===
+
+2019-11-19 
+- Add built-in query object cache feature, avoid re-compilation for the same query string. [#16](https://github.com/antchfx/htmlquery/issues/16)
+- Added LoadDoc [18](https://github.com/antchfx/htmlquery/pull/18)
+
+2019-10-05 
+- Add new methods that compatible with invalid XPath expression error: `QueryAll` and `Query`.
+- Add `QuerySelector` and `QuerySelectorAll` methods, supported reused your query object.
+
+2019-02-04
+- [#7](https://github.com/antchfx/htmlquery/issues/7) Removed deprecated `FindEach()` and `FindEachWithBreak()` methods.
+
+2018-12-28
+- Avoid adding duplicate elements to list for `Find()` method. [#6](https://github.com/antchfx/htmlquery/issues/6)
+
+Tutorial
+===
+
+```go
+func main() {
+	doc, err := htmlquery.LoadURL("https://www.bing.com/search?q=golang")
+	if err != nil {
+		panic(err)
+	}
+	// Find all news item.
+	list, err := htmlquery.QueryAll(doc, "//ol/li")
+	if err != nil {
+		panic(err)
+	}
+	for i, n := range list {
+		a := htmlquery.FindOne(n, "//a")
+		fmt.Printf("%d %s(%s)\n", i, htmlquery.InnerText(a), htmlquery.SelectAttr(a, "href"))
+	}
+}
+```
+
+List of supported XPath query packages
+===
+| Name                                              | Description                               |
+| ------------------------------------------------- | ----------------------------------------- |
+| [htmlquery](https://github.com/antchfx/htmlquery) | XPath query package for the HTML document |
+| [xmlquery](https://github.com/antchfx/xmlquery)   | XPath query package for the XML document  |
+| [jsonquery](https://github.com/antchfx/jsonquery) | XPath query package for the JSON document |
+
+Questions
+===
+Please let me know if you have any questions.

vendor/github.com/antchfx/htmlquery/cache.go

@@ -0,0 +1,42 @@
+package htmlquery
+
+import (
+	"sync"
+
+	"github.com/antchfx/xpath"
+	"github.com/golang/groupcache/lru"
+)
+
+// DisableSelectorCache will disable caching for the query selector if value is true.
+var DisableSelectorCache = false
+
+// SelectorCacheMaxEntries allows how many selector object can be caching. Default is 50.
+// Will disable caching if SelectorCacheMaxEntries <= 0.
+var SelectorCacheMaxEntries = 50
+
+var (
+	cacheOnce  sync.Once
+	cache      *lru.Cache
+	cacheMutex sync.Mutex
+)
+
+func getQuery(expr string) (*xpath.Expr, error) {
+	if DisableSelectorCache || SelectorCacheMaxEntries <= 0 {
+		return xpath.Compile(expr)
+	}
+	cacheOnce.Do(func() {
+		cache = lru.New(SelectorCacheMaxEntries)
+	})
+	cacheMutex.Lock()
+	defer cacheMutex.Unlock()
+	if v, ok := cache.Get(expr); ok {
+		return v.(*xpath.Expr), nil
+	}
+	v, err := xpath.Compile(expr)
+	if err != nil {
+		return nil, err
+	}
+	cache.Add(expr, v)
+	return v, nil
+
+}

vendor/github.com/antchfx/htmlquery/go.mod

@@ -0,0 +1,9 @@
+module github.com/antchfx/htmlquery
+
+go 1.14
+
+require (
+	github.com/antchfx/xpath v1.1.6
+	github.com/golang/groupcache v0.0.0-20200121045136-8c9f03a8e57e
+	golang.org/x/net v0.0.0-20200421231249-e086a090c8fd
+)

vendor/github.com/antchfx/htmlquery/go.sum

@@ -0,0 +1,11 @@
+github.com/antchfx/xpath v1.1.6 h1:6sVh6hB5T6phw1pFpHRQ+C4bd8sNI+O58flqtg7h0R0=
+github.com/antchfx/xpath v1.1.6/go.mod h1:Yee4kTMuNiPYJ7nSNorELQMr1J33uOpXDMByNYhvtNk=
+github.com/golang/groupcache v0.0.0-20200121045136-8c9f03a8e57e h1:1r7pUrabqp18hOBcwBwiTsbnFeTZHV9eER/QT5JVZxY=
+github.com/golang/groupcache v0.0.0-20200121045136-8c9f03a8e57e/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/net v0.0.0-20200421231249-e086a090c8fd h1:QPwSajcTUrFriMF1nJ3XzgoqakqQEsnZf9LdXdi2nkI=
+golang.org/x/net v0.0.0-20200421231249-e086a090c8fd/go.mod h1:qpuaurCH72eLCgpAm/N6yyVIVM9cpaDIP3A8BGJEC5A=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

vendor/github.com/antchfx/htmlquery/query.go

@@ -0,0 +1,338 @@
+/*
+Package htmlquery provides extract data from HTML documents using XPath expression.
+*/
+package htmlquery
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+
+	"github.com/antchfx/xpath"
+	"golang.org/x/net/html"
+	"golang.org/x/net/html/charset"
+)
+
+var _ xpath.NodeNavigator = &NodeNavigator{}
+
+// CreateXPathNavigator creates a new xpath.NodeNavigator for the specified html.Node.
+func CreateXPathNavigator(top *html.Node) *NodeNavigator {
+	return &NodeNavigator{curr: top, root: top, attr: -1}
+}
+
+// Find is like QueryAll but Will panics if the expression `expr` cannot be parsed.
+//
+// See `QueryAll()` function.
+func Find(top *html.Node, expr string) []*html.Node {
+	nodes, err := QueryAll(top, expr)
+	if err != nil {
+		panic(err)
+	}
+	return nodes
+}
+
+// FindOne is like Query but will panics if the expression `expr` cannot be parsed.
+// See `Query()` function.
+func FindOne(top *html.Node, expr string) *html.Node {
+	node, err := Query(top, expr)
+	if err != nil {
+		panic(err)
+	}
+	return node
+}
+
+// QueryAll searches the html.Node that matches by the specified XPath expr.
+// Return an error if the expression `expr` cannot be parsed.
+func QueryAll(top *html.Node, expr string) ([]*html.Node, error) {
+	exp, err := getQuery(expr)
+	if err != nil {
+		return nil, err
+	}
+	nodes := QuerySelectorAll(top, exp)
+	return nodes, nil
+}
+
+// Query searches the html.Node that matches by the specified XPath expr,
+// and return the first element of matched html.Node.
+//
+// Return an error if the expression `expr` cannot be parsed.
+func Query(top *html.Node, expr string) (*html.Node, error) {
+	exp, err := getQuery(expr)
+	if err != nil {
+		return nil, err
+	}
+	return QuerySelector(top, exp), nil
+}
+
+// QuerySelector returns the first matched html.Node by the specified XPath selector.
+func QuerySelector(top *html.Node, selector *xpath.Expr) *html.Node {
+	t := selector.Select(CreateXPathNavigator(top))
+	if t.MoveNext() {
+		return getCurrentNode(t.Current().(*NodeNavigator))
+	}
+	return nil
+}
+
+// QuerySelectorAll searches all of the html.Node that matches the specified XPath selectors.
+func QuerySelectorAll(top *html.Node, selector *xpath.Expr) []*html.Node {
+	var elems []*html.Node
+	t := selector.Select(CreateXPathNavigator(top))
+	for t.MoveNext() {
+		nav := t.Current().(*NodeNavigator)
+		n := getCurrentNode(nav)
+		// avoid adding duplicate nodes.
+		if len(elems) > 0 && (elems[0] == n || (nav.NodeType() == xpath.AttributeNode &&
+			nav.LocalName() == elems[0].Data && nav.Value() == InnerText(elems[0]))) {
+			continue
+		}
+		elems = append(elems, n)
+	}
+	return elems
+}
+
+// LoadURL loads the HTML document from the specified URL.
+func LoadURL(url string) (*html.Node, error) {
+	resp, err := http.Get(url)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	r, err := charset.NewReader(resp.Body, resp.Header.Get("Content-Type"))
+	if err != nil {
+		return nil, err
+	}
+	return html.Parse(r)
+}
+
+// LoadDoc loads the HTML document from the specified file path.
+func LoadDoc(path string) (*html.Node, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	return html.Parse(bufio.NewReader(f))
+}
+
+func getCurrentNode(n *NodeNavigator) *html.Node {
+	if n.NodeType() == xpath.AttributeNode {
+		childNode := &html.Node{
+			Type: html.TextNode,
+			Data: n.Value(),
+		}
+		return &html.Node{
+			Type:       html.ElementNode,
+			Data:       n.LocalName(),
+			FirstChild: childNode,
+			LastChild:  childNode,
+		}
+
+	}
+	return n.curr
+}
+
+// Parse returns the parse tree for the HTML from the given Reader.
+func Parse(r io.Reader) (*html.Node, error) {
+	return html.Parse(r)
+}
+
+// InnerText returns the text between the start and end tags of the object.
+func InnerText(n *html.Node) string {
+	var output func(*bytes.Buffer, *html.Node)
+	output = func(buf *bytes.Buffer, n *html.Node) {
+		switch n.Type {
+		case html.TextNode:
+			buf.WriteString(n.Data)
+			return
+		case html.CommentNode:
+			return
+		}
+		for child := n.FirstChild; child != nil; child = child.NextSibling {
+			output(buf, child)
+		}
+	}
+
+	var buf bytes.Buffer
+	output(&buf, n)
+	return buf.String()
+}
+
+// SelectAttr returns the attribute value with the specified name.
+func SelectAttr(n *html.Node, name string) (val string) {
+	if n == nil {
+		return
+	}
+	if n.Type == html.ElementNode && n.Parent == nil && name == n.Data {
+		return InnerText(n)
+	}
+	for _, attr := range n.Attr {
+		if attr.Key == name {
+			val = attr.Val
+			break
+		}
+	}
+	return
+}
+
+// OutputHTML returns the text including tags name.
+func OutputHTML(n *html.Node, self bool) string {
+	var buf bytes.Buffer
+	if self {
+		html.Render(&buf, n)
+	} else {
+		for n := n.FirstChild; n != nil; n = n.NextSibling {
+			html.Render(&buf, n)
+		}
+	}
+	return buf.String()
+}
+
+type NodeNavigator struct {
+	root, curr *html.Node
+	attr       int
+}
+
+func (h *NodeNavigator) Current() *html.Node {
+	return h.curr
+}
+
+func (h *NodeNavigator) NodeType() xpath.NodeType {
+	switch h.curr.Type {
+	case html.CommentNode:
+		return xpath.CommentNode
+	case html.TextNode:
+		return xpath.TextNode
+	case html.DocumentNode:
+		return xpath.RootNode
+	case html.ElementNode:
+		if h.attr != -1 {
+			return xpath.AttributeNode
+		}
+		return xpath.ElementNode
+	case html.DoctypeNode:
+		// ignored <!DOCTYPE HTML> declare and as Root-Node type.
+		return xpath.RootNode
+	}
+	panic(fmt.Sprintf("unknown HTML node type: %v", h.curr.Type))
+}
+
+func (h *NodeNavigator) LocalName() string {
+	if h.attr != -1 {
+		return h.curr.Attr[h.attr].Key
+	}
+	return h.curr.Data
+}
+
+func (*NodeNavigator) Prefix() string {
+	return ""
+}
+
+func (h *NodeNavigator) Value() string {
+	switch h.curr.Type {
+	case html.CommentNode:
+		return h.curr.Data
+	case html.ElementNode:
+		if h.attr != -1 {
+			return h.curr.Attr[h.attr].Val
+		}
+		return InnerText(h.curr)
+	case html.TextNode:
+		return h.curr.Data
+	}
+	return ""
+}
+
+func (h *NodeNavigator) Copy() xpath.NodeNavigator {
+	n := *h
+	return &n
+}
+
+func (h *NodeNavigator) MoveToRoot() {
+	h.curr = h.root
+}
+
+func (h *NodeNavigator) MoveToParent() bool {
+	if h.attr != -1 {
+		h.attr = -1
+		return true
+	} else if node := h.curr.Parent; node != nil {
+		h.curr = node
+		return true
+	}
+	return false
+}
+
+func (h *NodeNavigator) MoveToNextAttribute() bool {
+	if h.attr >= len(h.curr.Attr)-1 {
+		return false
+	}
+	h.attr++
+	return true
+}
+
+func (h *NodeNavigator) MoveToChild() bool {
+	if h.attr != -1 {
+		return false
+	}
+	if node := h.curr.FirstChild; node != nil {
+		h.curr = node
+		return true
+	}
+	return false
+}
+
+func (h *NodeNavigator) MoveToFirst() bool {
+	if h.attr != -1 || h.curr.PrevSibling == nil {
+		return false
+	}
+	for {
+		node := h.curr.PrevSibling
+		if node == nil {
+			break
+		}
+		h.curr = node
+	}
+	return true
+}
+
+func (h *NodeNavigator) String() string {
+	return h.Value()
+}
+
+func (h *NodeNavigator) MoveToNext() bool {
+	if h.attr != -1 {
+		return false
+	}
+	if node := h.curr.NextSibling; node != nil {
+		h.curr = node
+		return true
+	}
+	return false
+}
+
+func (h *NodeNavigator) MoveToPrevious() bool {
+	if h.attr != -1 {
+		return false
+	}
+	if node := h.curr.PrevSibling; node != nil {
+		h.curr = node
+		return true
+	}
+	return false
+}
+
+func (h *NodeNavigator) MoveTo(other xpath.NodeNavigator) bool {
+	node, ok := other.(*NodeNavigator)
+	if !ok || node.root != h.root {
+		return false
+	}
+
+	h.curr = node.curr
+	h.attr = node.attr
+	return true
+}

vendor/github.com/antchfx/xmlquery/.gitignore

@@ -0,0 +1,32 @@
+# vscode
+.vscode
+debug
+*.test
+
+./build
+
+# Compiled Object files, Static and Dynamic libs (Shared Objects)
+*.o
+*.a
+*.so
+
+
+# Folders
+_obj
+_test
+
+# Architecture specific extensions/prefixes
+*.[568vq]
+[568vq].out
+
+*.cgo1.go
+*.cgo2.c
+_cgo_defun.c
+_cgo_gotypes.go
+_cgo_export.*
+
+_testmain.go
+
+*.exe
+*.test
+*.prof

vendor/github.com/antchfx/xmlquery/.travis.yml

@@ -0,0 +1,17 @@
+language: go
+
+go:
+  - 1.9.x
+  - 1.12.x
+  - 1.13.x
+  - 1.14.x
+  - 1.15.x
+
+install:
+  - go get golang.org/x/net/html/charset
+  - go get github.com/antchfx/xpath
+  - go get github.com/mattn/goveralls
+  - go get github.com/golang/groupcache
+
+script:
+  - $HOME/gopath/bin/goveralls -service=travis-ci

vendor/github.com/antchfx/xmlquery/LICENSE

@@ -0,0 +1,17 @@
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

vendor/github.com/antchfx/xmlquery/README.md

@@ -0,0 +1,262 @@
+xmlquery
+====
+[![Build Status](https://travis-ci.org/antchfx/xmlquery.svg?branch=master)](https://travis-ci.org/antchfx/xmlquery)
+[![Coverage Status](https://coveralls.io/repos/github/antchfx/xmlquery/badge.svg?branch=master)](https://coveralls.io/github/antchfx/xmlquery?branch=master)
+[![GoDoc](https://godoc.org/github.com/antchfx/xmlquery?status.svg)](https://godoc.org/github.com/antchfx/xmlquery)
+[![Go Report Card](https://goreportcard.com/badge/github.com/antchfx/xmlquery)](https://goreportcard.com/report/github.com/antchfx/xmlquery)
+
+Overview
+===
+
+`xmlquery` is an XPath query package for XML documents, allowing you to extract 
+data or evaluate from XML documents with an XPath expression.
+
+`xmlquery` has a built-in query object caching feature that caches recently used
+XPATH query strings. Enabling caching can avoid recompile XPath expression for 
+each query. 
+
+Change Logs
+===
+
+2020-08-??
+- Add XML stream loading and parsing support.
+
+2019-11-11 
+- Add XPath query caching.
+
+2019-10-05 
+- Add new methods compatible with invalid XPath expression error: `QueryAll` and `Query`.
+- Add `QuerySelector` and `QuerySelectorAll` methods, support for reused query objects.
+- PR [#12](https://github.com/antchfx/xmlquery/pull/12) (Thanks @FrancescoIlario)
+- PR [#11](https://github.com/antchfx/xmlquery/pull/11) (Thanks @gjvnq)
+
+2018-12-23
+- Added XML output including comment nodes. [#9](https://github.com/antchfx/xmlquery/issues/9)
+
+2018-12-03
+- Added support to attribute name with namespace prefix and XML output. [#6](https://github.com/antchfx/xmlquery/issues/6)
+
+Installation
+====
+```
+ $ go get github.com/antchfx/xmlquery
+```
+
+Getting Started
+===
+
+### Find specified XPath query.
+
+```go
+list, err := xmlquery.QueryAll(doc, "a")
+if err != nil {
+	panic(err)
+}
+```
+
+#### Parse an XML from URL.
+
+```go
+doc, err := xmlquery.LoadURL("http://www.example.com/sitemap.xml")
+```
+
+#### Parse an XML from string.
+
+```go
+s := `<?xml version="1.0" encoding="utf-8"?><rss version="2.0"></rss>`
+doc, err := xmlquery.Parse(strings.NewReader(s))
+```
+
+#### Parse an XML from io.Reader.
+
+```go
+f, err := os.Open("../books.xml")
+doc, err := xmlquery.Parse(f)
+```
+
+#### Parse an XML in a stream fashion (simple case without elements filtering).
+
+```go
+f, err := os.Open("../books.xml")
+p, err := xmlquery.CreateStreamParser(f, "/bookstore/book")
+for {
+	n, err := p.Read()
+	if err == io.EOF {
+		break
+	}
+	if err != nil {
+		...
+	}
+}
+```
+
+#### Parse an XML in a stream fashion (simple case advanced element filtering).
+
+```go
+f, err := os.Open("../books.xml")
+p, err := xmlquery.CreateStreamParser(f, "/bookstore/book", "/bookstore/book[price>=10]")
+for {
+	n, err := p.Read()
+	if err == io.EOF {
+		break
+	}
+	if err != nil {
+		...
+	}
+}
+```
+
+#### Find authors of all books in the bookstore.
+
+```go
+list := xmlquery.Find(doc, "//book//author")
+// or
+list := xmlquery.Find(doc, "//author")
+```
+
+#### Find the second book.
+
+```go
+book := xmlquery.FindOne(doc, "//book[2]")
+```
+
+#### Find all book elements and only get `id` attribute. (New Feature)
+
+```go
+list := xmlquery.Find(doc,"//book/@id")
+```
+
+#### Find all books with id `bk104`.
+
+```go
+list := xmlquery.Find(doc, "//book[@id='bk104']")
+```
+
+#### Find all books with price less than 5.
+
+```go
+list := xmlquery.Find(doc, "//book[price<5]")
+```
+
+#### Evaluate total price of all books.
+
+```go
+expr, err := xpath.Compile("sum(//book/price)")
+price := expr.Evaluate(xmlquery.CreateXPathNavigator(doc)).(float64)
+fmt.Printf("total price: %f\n", price)
+```
+
+#### Evaluate number of all book elements.
+
+```go
+expr, err := xpath.Compile("count(//book)")
+price := expr.Evaluate(xmlquery.CreateXPathNavigator(doc)).(float64)
+```
+
+FAQ
+====
+
+#### `Find()` vs `QueryAll()`, which is better?
+
+`Find` and `QueryAll` both do the same thing: searches all of matched XML nodes.
+`Find` panics if provided with an invalid XPath query, while `QueryAll` returns
+an error.
+
+#### Can I save my query expression object for the next query?
+
+Yes, you can. We provide `QuerySelector` and `QuerySelectorAll` methods; they 
+accept your query expression object.
+
+Caching a query expression object avoids recompiling the XPath query 
+expression, improving query performance.
+
+#### Create XML document.
+
+```go
+doc := &xmlquery.Node{
+	Type: xmlquery.DeclarationNode,
+	Data: "xml",
+	Attr: []xml.Attr{
+		xml.Attr{Name: xml.Name{Local: "version"}, Value: "1.0"},
+	},
+}
+root := &xmlquery.Node{
+	Data: "rss",
+	Type: xmlquery.ElementNode,
+}
+doc.FirstChild = root
+channel := &xmlquery.Node{
+	Data: "channel",
+	Type: xmlquery.ElementNode,
+}
+root.FirstChild = channel
+title := &xmlquery.Node{
+	Data: "title",
+	Type: xmlquery.ElementNode,
+}
+title_text := &xmlquery.Node{
+	Data: "W3Schools Home Page",
+	Type: xmlquery.TextNode,
+}
+title.FirstChild = title_text
+channel.FirstChild = title
+fmt.Println(doc.OutputXML(true))
+// <?xml version="1.0"?><rss><channel><title>W3Schools Home Page</title></channel></rss>
+```
+
+Quick Tutorial
+===
+
+```go
+import (
+	"github.com/antchfx/xmlquery"
+)
+
+func main(){
+	s := `<?xml version="1.0" encoding="UTF-8" ?>
+<rss version="2.0">
+<channel>
+  <title>W3Schools Home Page</title>
+  <link>https://www.w3schools.com</link>
+  <description>Free web building tutorials</description>
+  <item>
+    <title>RSS Tutorial</title>
+    <link>https://www.w3schools.com/xml/xml_rss.asp</link>
+    <description>New RSS tutorial on W3Schools</description>
+  </item>
+  <item>
+    <title>XML Tutorial</title>
+    <link>https://www.w3schools.com/xml</link>
+    <description>New XML tutorial on W3Schools</description>
+  </item>
+</channel>
+</rss>`
+
+	doc, err := xmlquery.Parse(strings.NewReader(s))
+	if err != nil {
+		panic(err)
+	}
+	channel := xmlquery.FindOne(doc, "//channel")
+	if n := channel.SelectElement("title"); n != nil {
+		fmt.Printf("title: %s\n", n.InnerText())
+	}
+	if n := channel.SelectElement("link"); n != nil {
+		fmt.Printf("link: %s\n", n.InnerText())
+	}
+	for i, n := range xmlquery.Find(doc, "//item/title") {
+		fmt.Printf("#%d %s\n", i, n.InnerText())
+	}
+}
+```
+
+List of supported XPath query packages
+===
+| Name                                              | Description                               |
+| ------------------------------------------------- | ----------------------------------------- |
+| [htmlquery](https://github.com/antchfx/htmlquery) | XPath query package for HTML documents    |
+| [xmlquery](https://github.com/antchfx/xmlquery)   | XPath query package for XML documents     |
+| [jsonquery](https://github.com/antchfx/jsonquery) | XPath query package for JSON documents    |
+
+ Questions
+===
+Please let me know if you have any questions

vendor/github.com/antchfx/xmlquery/books.xml

@@ -0,0 +1,121 @@
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/xsl" ?>
+<bookstore specialty="novel">
+   <book id="bk101">
+      <author>Gambardella, Matthew</author>
+      <title>XML Developer's Guide</title>
+      <genre>Computer</genre>
+      <price>44.95</price>
+      <publish_date>2000-10-01</publish_date>
+      <description>An in-depth look at creating applications 
+      with XML.</description>
+   </book>
+   <book id="bk102">
+      <author>Ralls, Kim</author>
+      <title>Midnight Rain</title>
+      <genre>Fantasy</genre>
+      <price>5.95</price>
+      <publish_date>2000-12-16</publish_date>
+      <description>A former architect battles corporate zombies, 
+      an evil sorceress, and her own childhood to become queen 
+      of the world.</description>
+   </book>
+   <book id="bk103">
+      <author>Corets, Eva</author>
+      <title>Maeve Ascendant</title>
+      <genre>Fantasy</genre>
+      <price>5.95</price>
+      <publish_date>2000-11-17</publish_date>
+      <description>After the collapse of a nanotechnology 
+      society in England, the young survivors lay the 
+      foundation for a new society.</description>
+   </book>
+   <book id="bk104">
+      <author>Corets, Eva</author>
+      <title>Oberon's Legacy</title>
+      <genre>Fantasy</genre>
+      <price>5.95</price>
+      <publish_date>2001-03-10</publish_date>
+      <description>In post-apocalypse England, the mysterious 
+      agent known only as Oberon helps to create a new life 
+      for the inhabitants of London. Sequel to Maeve 
+      Ascendant.</description>
+   </book>
+   <book id="bk105">
+      <author>Corets, Eva</author>
+      <title>The Sundered Grail</title>
+      <genre>Fantasy</genre>
+      <price>5.95</price>
+      <publish_date>2001-09-10</publish_date>
+      <description>The two daughters of Maeve, half-sisters, 
+      battle one another for control of England. Sequel to 
+      Oberon's Legacy.</description>
+   </book>
+   <book id="bk106">
+      <author>Randall, Cynthia</author>
+      <title>Lover Birds</title>
+      <genre>Romance</genre>
+      <price>4.95</price>
+      <publish_date>2000-09-02</publish_date>
+      <description>When Carla meets Paul at an ornithology 
+      conference, tempers fly as feathers get ruffled.</description>
+   </book>
+   <book id="bk107">
+      <author>Thurman, Paula</author>
+      <title>Splish Splash</title>
+      <genre>Romance</genre>
+      <price>4.95</price>
+      <publish_date>2000-11-02</publish_date>
+      <description>A deep sea diver finds true love twenty 
+      thousand leagues beneath the sea.</description>
+   </book>
+   <book id="bk108">
+      <author>Knorr, Stefan</author>
+      <title>Creepy Crawlies</title>
+      <genre>Horror</genre>
+      <price>4.95</price>
+      <publish_date>2000-12-06</publish_date>
+      <description>An anthology of horror stories about roaches,
+      centipedes, scorpions  and other insects.</description>
+   </book>
+   <book id="bk109">
+      <author>Kress, Peter</author>
+      <title>Paradox Lost</title>
+      <genre>Science Fiction</genre>
+      <price>6.95</price>
+      <publish_date>2000-11-02</publish_date>
+      <description>After an inadvertant trip through a Heisenberg
+      Uncertainty Device, James Salway discovers the problems 
+      of being quantum.</description>
+   </book>
+   <book id="bk110">
+      <author>O'Brien, Tim</author>
+      <title>Microsoft .NET: The Programming Bible</title>
+      <genre>Computer</genre>
+      <price>36.95</price>
+      <publish_date>2000-12-09</publish_date>
+      <description>Microsoft's .NET initiative is explored in 
+      detail in this deep programmer's reference.</description>
+   </book>
+   <book id="bk111">
+      <author>O'Brien, Tim</author>
+      <title>MSXML3: A Comprehensive Guide</title>
+      <genre>Computer</genre>
+      <price>36.95</price>
+      <publish_date>2000-12-01</publish_date>
+      <description>The Microsoft MSXML3 parser is covered in 
+      detail, with attention to XML DOM interfaces, XSLT processing, 
+      SAX and more.</description>
+   </book>
+   <book id="bk112">
+      <author>Galos, Mike</author>
+      <title>Visual Studio 7: A Comprehensive Guide</title>
+      <genre>Computer</genre>
+      <price>49.95</price>
+      <publish_date>2001-04-16</publish_date>
+      <description>Microsoft Visual Studio 7 is explored in depth,
+      looking at how Visual Basic, Visual C++, C#, and ASP+ are 
+      integrated into a comprehensive development 
+      environment.</description>
+   </book>
+</bookstore>

vendor/github.com/antchfx/xmlquery/cache.go

@@ -0,0 +1,43 @@
+package xmlquery
+
+import (
+	"sync"
+
+	"github.com/golang/groupcache/lru"
+
+	"github.com/antchfx/xpath"
+)
+
+// DisableSelectorCache will disable caching for the query selector if value is true.
+var DisableSelectorCache = false
+
+// SelectorCacheMaxEntries allows how many selector object can be caching. Default is 50.
+// Will disable caching if SelectorCacheMaxEntries <= 0.
+var SelectorCacheMaxEntries = 50
+
+var (
+	cacheOnce  sync.Once
+	cache      *lru.Cache
+	cacheMutex sync.Mutex
+)
+
+func getQuery(expr string) (*xpath.Expr, error) {
+	if DisableSelectorCache || SelectorCacheMaxEntries <= 0 {
+		return xpath.Compile(expr)
+	}
+	cacheOnce.Do(func() {
+		cache = lru.New(SelectorCacheMaxEntries)
+	})
+	cacheMutex.Lock()
+	defer cacheMutex.Unlock()
+	if v, ok := cache.Get(expr); ok {
+		return v.(*xpath.Expr), nil
+	}
+	v, err := xpath.Compile(expr)
+	if err != nil {
+		return nil, err
+	}
+	cache.Add(expr, v)
+	return v, nil
+
+}

vendor/github.com/antchfx/xmlquery/cached_reader.go

@@ -0,0 +1,69 @@
+package xmlquery
+
+import (
+	"bufio"
+)
+
+type cachedReader struct {
+	buffer *bufio.Reader
+	cache []byte
+	cacheCap int
+	cacheLen int
+	caching bool
+}
+
+func newCachedReader(r *bufio.Reader) *cachedReader {
+	return &cachedReader{
+		buffer:   r,
+		cache:    make([]byte, 4096),
+		cacheCap: 4096,
+		cacheLen: 0,
+		caching:  false,
+	}
+}
+
+func (c *cachedReader) StartCaching() {
+	c.cacheLen = 0
+	c.caching = true
+}
+
+func (c *cachedReader) ReadByte() (byte, error) {
+	if !c.caching {
+		return c.buffer.ReadByte()
+	}
+	b, err := c.buffer.ReadByte()
+	if err != nil {
+		return b, err
+	}
+	if c.cacheLen < c.cacheCap {
+		c.cache[c.cacheLen] = b
+		c.cacheLen++
+	}
+	return b, err
+}
+
+func (c *cachedReader) Cache() []byte {
+	return c.cache[:c.cacheLen]
+}
+
+func (c *cachedReader) StopCaching() {
+	c.caching = false
+}
+
+func (c *cachedReader) Read(p []byte) (int, error) {
+	n, err := c.buffer.Read(p)
+	if err != nil {
+		return n, err
+	}
+	if c.caching && c.cacheLen < c.cacheCap {
+		for i := 0; i < n; i++ {
+			c.cache[c.cacheLen] = p[i]
+			c.cacheLen++
+			if c.cacheLen >= c.cacheCap {
+				break
+			}
+		}
+	}
+	return n, err
+}
+

vendor/github.com/antchfx/xmlquery/go.mod

@@ -0,0 +1,9 @@
+module github.com/antchfx/xmlquery
+
+go 1.14
+
+require (
+	github.com/antchfx/xpath v1.1.10
+	github.com/golang/groupcache v0.0.0-20200121045136-8c9f03a8e57e
+	golang.org/x/net v0.0.0-20200813134508-3edf25e44fcc
+)

vendor/github.com/antchfx/xmlquery/go.sum

@@ -0,0 +1,14 @@
+github.com/antchfx/xpath v1.1.10 h1:cJ0pOvEdN/WvYXxvRrzQH9x5QWKpzHacYO8qzCcDYAg=
+github.com/antchfx/xpath v1.1.10/go.mod h1:Yee4kTMuNiPYJ7nSNorELQMr1J33uOpXDMByNYhvtNk=
+github.com/golang/groupcache v0.0.0-20200121045136-8c9f03a8e57e h1:1r7pUrabqp18hOBcwBwiTsbnFeTZHV9eER/QT5JVZxY=
+github.com/golang/groupcache v0.0.0-20200121045136-8c9f03a8e57e/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20200813134508-3edf25e44fcc h1:zK/HqS5bZxDptfPJNq8v7vJfXtkU7r9TLIoSr1bXaP4=
+golang.org/x/net v0.0.0-20200813134508-3edf25e44fcc/go.mod h1:/O7V0waA8r7cgGh81Ro3o1hOxt32SMVPicZroKQ2sZA=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

vendor/github.com/antchfx/xmlquery/node.go

@@ -0,0 +1,232 @@
+package xmlquery
+
+import (
+	"bytes"
+	"encoding/xml"
+	"fmt"
+	"strings"
+)
+
+// A NodeType is the type of a Node.
+type NodeType uint
+
+const (
+	// DocumentNode is a document object that, as the root of the document tree,
+	// provides access to the entire XML document.
+	DocumentNode NodeType = iota
+	// DeclarationNode is the document type declaration, indicated by the
+	// following tag (for example, <!DOCTYPE...> ).
+	DeclarationNode
+	// ElementNode is an element (for example, <item> ).
+	ElementNode
+	// TextNode is the text content of a node.
+	TextNode
+	// CharDataNode node <![CDATA[content]]>
+	CharDataNode
+	// CommentNode a comment (for example, <!-- my comment --> ).
+	CommentNode
+	// AttributeNode is an attribute of element.
+	AttributeNode
+)
+
+type Attr struct {
+	Name         xml.Name
+	Value        string
+	NamespaceURI string
+}
+
+// A Node consists of a NodeType and some Data (tag name for
+// element nodes, content for text) and are part of a tree of Nodes.
+type Node struct {
+	Parent, FirstChild, LastChild, PrevSibling, NextSibling *Node
+
+	Type         NodeType
+	Data         string
+	Prefix       string
+	NamespaceURI string
+	Attr         []Attr
+
+	level int // node level in the tree
+}
+
+// InnerText returns the text between the start and end tags of the object.
+func (n *Node) InnerText() string {
+	var output func(*bytes.Buffer, *Node)
+	output = func(buf *bytes.Buffer, n *Node) {
+		switch n.Type {
+		case TextNode, CharDataNode:
+			buf.WriteString(n.Data)
+		case CommentNode:
+		default:
+			for child := n.FirstChild; child != nil; child = child.NextSibling {
+				output(buf, child)
+			}
+		}
+	}
+
+	var buf bytes.Buffer
+	output(&buf, n)
+	return buf.String()
+}
+
+func (n *Node) sanitizedData(preserveSpaces bool) string {
+	if preserveSpaces {
+		return strings.Trim(n.Data, "\n\t")
+	}
+	return strings.TrimSpace(n.Data)
+}
+
+func calculatePreserveSpaces(n *Node, pastValue bool) bool {
+	if attr := n.SelectAttr("xml:space"); attr == "preserve" {
+		return true
+	} else if attr == "default" {
+		return false
+	}
+	return pastValue
+}
+
+func outputXML(buf *bytes.Buffer, n *Node, preserveSpaces bool) {
+	preserveSpaces = calculatePreserveSpaces(n, preserveSpaces)
+	switch n.Type {
+	case TextNode:
+		xml.EscapeText(buf, []byte(n.sanitizedData(preserveSpaces)))
+		return
+	case CharDataNode:
+		buf.WriteString("<![CDATA[")
+		buf.WriteString(n.Data)
+		buf.WriteString("]]>")
+		return
+	case CommentNode:
+		buf.WriteString("<!--")
+		buf.WriteString(n.Data)
+		buf.WriteString("-->")
+		return
+	case DeclarationNode:
+		buf.WriteString("<?" + n.Data)
+	default:
+		if n.Prefix == "" {
+			buf.WriteString("<" + n.Data)
+		} else {
+			buf.WriteString("<" + n.Prefix + ":" + n.Data)
+		}
+	}
+
+	for _, attr := range n.Attr {
+		if attr.Name.Space != "" {
+			buf.WriteString(fmt.Sprintf(` %s:%s=`, attr.Name.Space, attr.Name.Local))
+		} else {
+			buf.WriteString(fmt.Sprintf(` %s=`, attr.Name.Local))
+		}
+		buf.WriteByte('"')
+		xml.EscapeText(buf, []byte(attr.Value))
+		buf.WriteByte('"')
+	}
+	if n.Type == DeclarationNode {
+		buf.WriteString("?>")
+	} else {
+		buf.WriteString(">")
+	}
+	for child := n.FirstChild; child != nil; child = child.NextSibling {
+		outputXML(buf, child, preserveSpaces)
+	}
+	if n.Type != DeclarationNode {
+		if n.Prefix == "" {
+			buf.WriteString(fmt.Sprintf("</%s>", n.Data))
+		} else {
+			buf.WriteString(fmt.Sprintf("</%s:%s>", n.Prefix, n.Data))
+		}
+	}
+}
+
+// OutputXML returns the text that including tags name.
+func (n *Node) OutputXML(self bool) string {
+	var buf bytes.Buffer
+	if self {
+		outputXML(&buf, n, false)
+	} else {
+		for n := n.FirstChild; n != nil; n = n.NextSibling {
+			outputXML(&buf, n, false)
+		}
+	}
+
+	return buf.String()
+}
+
+// AddAttr adds a new attribute specified by 'key' and 'val' to a node 'n'.
+func AddAttr(n *Node, key, val string) {
+	var attr Attr
+	if i := strings.Index(key, ":"); i > 0 {
+		attr = Attr{
+			Name:  xml.Name{Space: key[:i], Local: key[i+1:]},
+			Value: val,
+		}
+	} else {
+		attr = Attr{
+			Name:  xml.Name{Local: key},
+			Value: val,
+		}
+	}
+
+	n.Attr = append(n.Attr, attr)
+}
+
+// AddChild adds a new node 'n' to a node 'parent' as its last child.
+func AddChild(parent, n *Node) {
+	n.Parent = parent
+	n.NextSibling = nil
+	if parent.FirstChild == nil {
+		parent.FirstChild = n
+		n.PrevSibling = nil
+	} else {
+		parent.LastChild.NextSibling = n
+		n.PrevSibling = parent.LastChild
+	}
+
+	parent.LastChild = n
+}
+
+// AddSibling adds a new node 'n' as a sibling of a given node 'sibling'.
+// Note it is not necessarily true that the new node 'n' would be added
+// immediately after 'sibling'. If 'sibling' isn't the last child of its
+// parent, then the new node 'n' will be added at the end of the sibling
+// chain of their parent.
+func AddSibling(sibling, n *Node) {
+	for t := sibling.NextSibling; t != nil; t = t.NextSibling {
+		sibling = t
+	}
+	n.Parent = sibling.Parent
+	sibling.NextSibling = n
+	n.PrevSibling = sibling
+	n.NextSibling = nil
+	if sibling.Parent != nil {
+		sibling.Parent.LastChild = n
+	}
+}
+
+// RemoveFromTree removes a node and its subtree from the document
+// tree it is in. If the node is the root of the tree, then it's no-op.
+func RemoveFromTree(n *Node) {
+	if n.Parent == nil {
+		return
+	}
+	if n.Parent.FirstChild == n {
+		if n.Parent.LastChild == n {
+			n.Parent.FirstChild = nil
+			n.Parent.LastChild = nil
+		} else {
+			n.Parent.FirstChild = n.NextSibling
+			n.NextSibling.PrevSibling = nil
+		}
+	} else {
+		if n.Parent.LastChild == n {
+			n.Parent.LastChild = n.PrevSibling
+			n.PrevSibling.NextSibling = nil
+		} else {
+			n.PrevSibling.NextSibling = n.NextSibling
+			n.NextSibling.PrevSibling = n.PrevSibling
+		}
+	}
+	n.Parent = nil
+	n.PrevSibling = nil
+	n.NextSibling = nil
+}

vendor/github.com/antchfx/xmlquery/options.go

@@ -0,0 +1,30 @@
+package xmlquery
+
+import (
+	"encoding/xml"
+)
+
+type ParserOptions struct{
+	Decoder *DecoderOptions
+}
+
+func (options ParserOptions) apply(parser *parser) {
+	if options.Decoder != nil {
+		(*options.Decoder).apply(parser.decoder)
+	}
+}
+
+// DecoderOptions implement the very same options than the standard
+// encoding/xml package. Please refer to this documentation:
+// https://golang.org/pkg/encoding/xml/#Decoder
+type DecoderOptions struct{
+	Strict    bool
+	AutoClose []string
+	Entity    map[string]string
+}
+
+func (options DecoderOptions) apply(decoder *xml.Decoder) {
+	decoder.Strict = options.Strict
+	decoder.AutoClose = options.AutoClose
+	decoder.Entity = options.Entity
+}

vendor/github.com/antchfx/xmlquery/parse.go

@@ -0,0 +1,365 @@
+package xmlquery
+
+import (
+	"bufio"
+	"encoding/xml"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"regexp"
+	"strings"
+
+	"github.com/antchfx/xpath"
+	"golang.org/x/net/html/charset"
+)
+
+var xmlMIMERegex = regexp.MustCompile(`(?i)((application|image|message|model)/((\w|\.|-)+\+?)?|text/)(wb)?xml`)
+
+// LoadURL loads the XML document from the specified URL.
+func LoadURL(url string) (*Node, error) {
+	resp, err := http.Get(url)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	// Make sure the Content-Type has a valid XML MIME type
+	if xmlMIMERegex.MatchString(resp.Header.Get("Content-Type")) {
+		return Parse(resp.Body)
+	}
+	return nil, fmt.Errorf("invalid XML document(%s)", resp.Header.Get("Content-Type"))
+}
+
+// Parse returns the parse tree for the XML from the given Reader.
+func Parse(r io.Reader) (*Node, error) {
+	return ParseWithOptions(r, ParserOptions{})
+}
+
+// ParseWithOptions is like parse, but with custom options
+func ParseWithOptions(r io.Reader, options ParserOptions) (*Node, error) {
+	p := createParser(r)
+	options.apply(p)
+	for {
+		_, err := p.parse()
+		if err == io.EOF {
+			return p.doc, nil
+		}
+		if err != nil {
+			return nil, err
+		}
+	}
+}
+
+type parser struct {
+	decoder             *xml.Decoder
+	doc                 *Node
+	space2prefix        map[string]string
+	level               int
+	prev                *Node
+	streamElementXPath  *xpath.Expr   // Under streaming mode, this specifies the xpath to the target element node(s).
+	streamElementFilter *xpath.Expr   // If specified, it provides further filtering on the target element.
+	streamNode          *Node         // Need to remember the last target node So we can clean it up upon next Read() call.
+	streamNodePrev      *Node         // Need to remember target node's prev so upon target node removal, we can restore correct prev.
+	reader              *cachedReader // Need to maintain a reference to the reader, so we can determine whether a node contains CDATA.
+}
+
+func createParser(r io.Reader) *parser {
+	reader := newCachedReader(bufio.NewReader(r))
+	p := &parser{
+		decoder:      xml.NewDecoder(reader),
+		doc:          &Node{Type: DocumentNode},
+		space2prefix: make(map[string]string),
+		level:        0,
+		reader:       reader,
+	}
+	// http://www.w3.org/XML/1998/namespace is bound by definition to the prefix xml.
+	p.space2prefix["http://www.w3.org/XML/1998/namespace"] = "xml"
+	p.decoder.CharsetReader = charset.NewReaderLabel
+	p.prev = p.doc
+	return p
+}
+
+func (p *parser) parse() (*Node, error) {
+	var streamElementNodeCounter int
+
+	for {
+		tok, err := p.decoder.Token()
+		if err != nil {
+			return nil, err
+		}
+
+		switch tok := tok.(type) {
+		case xml.StartElement:
+			if p.level == 0 {
+				// mising XML declaration
+				node := &Node{Type: DeclarationNode, Data: "xml", level: 1}
+				AddChild(p.prev, node)
+				p.level = 1
+				p.prev = node
+			}
+			// https://www.w3.org/TR/xml-names/#scoping-defaulting
+			for _, att := range tok.Attr {
+				if att.Name.Local == "xmlns" {
+					p.space2prefix[att.Value] = ""
+				} else if att.Name.Space == "xmlns" {
+					p.space2prefix[att.Value] = att.Name.Local
+				}
+			}
+
+			if tok.Name.Space != "" {
+				if _, found := p.space2prefix[tok.Name.Space]; !found {
+					return nil, errors.New("xmlquery: invalid XML document, namespace is missing")
+				}
+			}
+
+			attributes := make([]Attr, len(tok.Attr))
+			for i, att := range tok.Attr {
+				name := att.Name
+				if prefix, ok := p.space2prefix[name.Space]; ok {
+					name.Space = prefix
+				}
+				attributes[i] = Attr{
+					Name:         name,
+					Value:        att.Value,
+					NamespaceURI: att.Name.Space,
+				}
+			}
+
+			node := &Node{
+				Type:         ElementNode,
+				Data:         tok.Name.Local,
+				Prefix:       p.space2prefix[tok.Name.Space],
+				NamespaceURI: tok.Name.Space,
+				Attr:         attributes,
+				level:        p.level,
+			}
+
+			if p.level == p.prev.level {
+				AddSibling(p.prev, node)
+			} else if p.level > p.prev.level {
+				AddChild(p.prev, node)
+			} else if p.level < p.prev.level {
+				for i := p.prev.level - p.level; i > 1; i-- {
+					p.prev = p.prev.Parent
+				}
+				AddSibling(p.prev.Parent, node)
+			}
+			// If we're in the streaming mode, we need to remember the node if it is the target node
+			// so that when we finish processing the node's EndElement, we know how/what to return to
+			// caller. Also we need to remove the target node from the tree upon next Read() call so
+			// memory doesn't grow unbounded.
+			if p.streamElementXPath != nil {
+				if p.streamNode == nil {
+					if QuerySelector(p.doc, p.streamElementXPath) != nil {
+						p.streamNode = node
+						p.streamNodePrev = p.prev
+						streamElementNodeCounter = 1
+					}
+				} else {
+					streamElementNodeCounter++
+				}
+			}
+			p.prev = node
+			p.level++
+			p.reader.StartCaching()
+		case xml.EndElement:
+			p.level--
+			// If we're in streaming mode, and we already have a potential streaming
+			// target node identified (p.streamNode != nil) then we need to check if
+			// this is the real one we want to return to caller.
+			if p.streamNode != nil {
+				streamElementNodeCounter--
+				if streamElementNodeCounter == 0 {
+					// Now we know this element node is the at least passing the initial
+					// p.streamElementXPath check and is a potential target node candidate.
+					// We need to have 1 more check with p.streamElementFilter (if given) to
+					// ensure it is really the element node we want.
+					// The reason we need a two-step check process is because the following
+					// situation:
+					//   <AAA><BBB>b1</BBB></AAA>
+					// And say the p.streamElementXPath = "/AAA/BBB[. != 'b1']". Now during
+					// xml.StartElement time, the <BBB> node is still empty, so it will pass
+					// the p.streamElementXPath check. However, eventually we know this <BBB>
+					// shouldn't be returned to the caller. Having a second more fine-grained
+					// filter check ensures that. So in this case, the caller should really
+					// setup the stream parser with:
+					//   streamElementXPath = "/AAA/BBB["
+					//   streamElementFilter = "/AAA/BBB[. != 'b1']"
+					if p.streamElementFilter == nil || QuerySelector(p.doc, p.streamElementFilter) != nil {
+						return p.streamNode, nil
+					}
+					// otherwise, this isn't our target node, clean things up.
+					// note we also remove the underlying *Node from the node tree, to prevent
+					// future stream node candidate selection error.
+					RemoveFromTree(p.streamNode)
+					p.prev = p.streamNodePrev
+					p.streamNode = nil
+					p.streamNodePrev = nil
+				}
+			}
+		case xml.CharData:
+			p.reader.StopCaching()
+			// First, normalize the cache...
+			cached := strings.ToUpper(string(p.reader.Cache()))
+			nodeType := TextNode
+			if strings.HasPrefix(cached, "<![CDATA[") {
+				nodeType = CharDataNode
+			}
+
+			node := &Node{Type: nodeType, Data: string(tok), level: p.level}
+			if p.level == p.prev.level {
+				AddSibling(p.prev, node)
+			} else if p.level > p.prev.level {
+				AddChild(p.prev, node)
+			} else if p.level < p.prev.level {
+				for i := p.prev.level - p.level; i > 1; i-- {
+					p.prev = p.prev.Parent
+				}
+				AddSibling(p.prev.Parent, node)
+			}
+			p.reader.StartCaching()
+		case xml.Comment:
+			node := &Node{Type: CommentNode, Data: string(tok), level: p.level}
+			if p.level == p.prev.level {
+				AddSibling(p.prev, node)
+			} else if p.level > p.prev.level {
+				AddChild(p.prev, node)
+			} else if p.level < p.prev.level {
+				for i := p.prev.level - p.level; i > 1; i-- {
+					p.prev = p.prev.Parent
+				}
+				AddSibling(p.prev.Parent, node)
+			}
+		case xml.ProcInst: // Processing Instruction
+			if p.prev.Type != DeclarationNode {
+				p.level++
+			}
+			node := &Node{Type: DeclarationNode, Data: tok.Target, level: p.level}
+			pairs := strings.Split(string(tok.Inst), " ")
+			for _, pair := range pairs {
+				pair = strings.TrimSpace(pair)
+				if i := strings.Index(pair, "="); i > 0 {
+					AddAttr(node, pair[:i], strings.Trim(pair[i+1:], `"`))
+				}
+			}
+			if p.level == p.prev.level {
+				AddSibling(p.prev, node)
+			} else if p.level > p.prev.level {
+				AddChild(p.prev, node)
+			}
+			p.prev = node
+		case xml.Directive:
+		}
+	}
+}
+
+// StreamParser enables loading and parsing an XML document in a streaming
+// fashion.
+type StreamParser struct {
+	p *parser
+}
+
+// CreateStreamParser creates a StreamParser. Argument streamElementXPath is
+// required.
+// Argument streamElementFilter is optional and should only be used in advanced
+// scenarios.
+//
+// Scenario 1: simple case:
+//  xml := `<AAA><BBB>b1</BBB><BBB>b2</BBB></AAA>`
+//  sp, err := CreateStreamParser(strings.NewReader(xml), "/AAA/BBB")
+//  if err != nil {
+//      panic(err)
+//  }
+//  for {
+//      n, err := sp.Read()
+//      if err != nil {
+//          break
+//      }
+//      fmt.Println(n.OutputXML(true))
+//  }
+// Output will be:
+//   <BBB>b1</BBB>
+//   <BBB>b2</BBB>
+//
+// Scenario 2: advanced case:
+//  xml := `<AAA><BBB>b1</BBB><BBB>b2</BBB></AAA>`
+//  sp, err := CreateStreamParser(strings.NewReader(xml), "/AAA/BBB", "/AAA/BBB[. != 'b1']")
+//  if err != nil {
+//      panic(err)
+//  }
+//  for {
+//      n, err := sp.Read()
+//      if err != nil {
+//          break
+//      }
+//      fmt.Println(n.OutputXML(true))
+//  }
+// Output will be:
+//   <BBB>b2</BBB>
+//
+// As the argument names indicate, streamElementXPath should be used for
+// providing xpath query pointing to the target element node only, no extra
+// filtering on the element itself or its children; while streamElementFilter,
+// if needed, can provide additional filtering on the target element and its
+// children.
+//
+// CreateStreamParser returns an error if either streamElementXPath or
+// streamElementFilter, if provided, cannot be successfully parsed and compiled
+// into a valid xpath query.
+func CreateStreamParser(r io.Reader, streamElementXPath string, streamElementFilter ...string) (*StreamParser, error) {
+    return CreateStreamParserWithOptions(r, ParserOptions{}, streamElementXPath, streamElementFilter...)
+}
+
+// CreateStreamParserWithOptions is like CreateStreamParser, but with custom options
+func CreateStreamParserWithOptions(
+	r io.Reader,
+	options ParserOptions,
+	streamElementXPath string,
+	streamElementFilter ...string,
+) (*StreamParser, error) {
+	elemXPath, err := getQuery(streamElementXPath)
+	if err != nil {
+		return nil, fmt.Errorf("invalid streamElementXPath '%s', err: %s", streamElementXPath, err.Error())
+	}
+	elemFilter := (*xpath.Expr)(nil)
+	if len(streamElementFilter) > 0 {
+		elemFilter, err = getQuery(streamElementFilter[0])
+		if err != nil {
+			return nil, fmt.Errorf("invalid streamElementFilter '%s', err: %s", streamElementFilter[0], err.Error())
+		}
+	}
+	parser := createParser(r)
+	options.apply(parser)
+	sp := &StreamParser{
+		p: parser,
+	}
+	sp.p.streamElementXPath = elemXPath
+	sp.p.streamElementFilter = elemFilter
+	return sp, nil
+}
+
+// Read returns a target node that satisfies the XPath specified by caller at
+// StreamParser creation time. If there is no more satisfying target nodes after
+// reading the rest of the XML document, io.EOF will be returned. At any time,
+// any XML parsing error encountered will be returned, and the stream parsing
+// stopped. Calling Read() after an error is returned (including io.EOF) results
+// undefined behavior. Also note, due to the streaming nature, calling Read()
+// will automatically remove any previous target node(s) from the document tree.
+func (sp *StreamParser) Read() (*Node, error) {
+	// Because this is a streaming read, we need to release/remove last
+	// target node from the node tree to free up memory.
+	if sp.p.streamNode != nil {
+		// We need to remove all siblings before the current stream node,
+		// because the document may contain unwanted nodes between the target
+		// ones (for example new line text node), which would otherwise
+		// accumulate as first childs, and slow down the stream over time
+		for sp.p.streamNode.PrevSibling != nil {
+			RemoveFromTree(sp.p.streamNode.PrevSibling)
+		}
+		sp.p.prev = sp.p.streamNode.Parent
+		RemoveFromTree(sp.p.streamNode)
+		sp.p.streamNode = nil
+		sp.p.streamNodePrev = nil
+	}
+	return sp.p.parse()
+}

vendor/github.com/antchfx/xmlquery/query.go

@@ -0,0 +1,309 @@
+/*
+Package xmlquery provides extract data from XML documents using XPath expression.
+*/
+package xmlquery
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/antchfx/xpath"
+)
+
+// SelectElements finds child elements with the specified name.
+func (n *Node) SelectElements(name string) []*Node {
+	return Find(n, name)
+}
+
+// SelectElement finds child elements with the specified name.
+func (n *Node) SelectElement(name string) *Node {
+	return FindOne(n, name)
+}
+
+// SelectAttr returns the attribute value with the specified name.
+func (n *Node) SelectAttr(name string) string {
+	if n.Type == AttributeNode {
+		if n.Data == name {
+			return n.InnerText()
+		}
+		return ""
+	}
+	var local, space string
+	local = name
+	if i := strings.Index(name, ":"); i > 0 {
+		space = name[:i]
+		local = name[i+1:]
+	}
+	for _, attr := range n.Attr {
+		if attr.Name.Local == local && attr.Name.Space == space {
+			return attr.Value
+		}
+	}
+	return ""
+}
+
+var _ xpath.NodeNavigator = &NodeNavigator{}
+
+// CreateXPathNavigator creates a new xpath.NodeNavigator for the specified
+// XML Node.
+func CreateXPathNavigator(top *Node) *NodeNavigator {
+	return &NodeNavigator{curr: top, root: top, attr: -1}
+}
+
+func getCurrentNode(it *xpath.NodeIterator) *Node {
+	n := it.Current().(*NodeNavigator)
+	if n.NodeType() == xpath.AttributeNode {
+		childNode := &Node{
+			Type: TextNode,
+			Data: n.Value(),
+		}
+		return &Node{
+			Parent:     n.curr,
+			Type:       AttributeNode,
+			Data:       n.LocalName(),
+			FirstChild: childNode,
+			LastChild:  childNode,
+		}
+	}
+	return n.curr
+}
+
+// Find is like QueryAll but panics if `expr` is not a valid XPath expression.
+// See `QueryAll()` function.
+func Find(top *Node, expr string) []*Node {
+	nodes, err := QueryAll(top, expr)
+	if err != nil {
+		panic(err)
+	}
+	return nodes
+}
+
+// FindOne is like Query but panics if `expr` is not a valid XPath expression.
+// See `Query()` function.
+func FindOne(top *Node, expr string) *Node {
+	node, err := Query(top, expr)
+	if err != nil {
+		panic(err)
+	}
+	return node
+}
+
+// QueryAll searches the XML Node that matches by the specified XPath expr.
+// Returns an error if the expression `expr` cannot be parsed.
+func QueryAll(top *Node, expr string) ([]*Node, error) {
+	exp, err := getQuery(expr)
+	if err != nil {
+		return nil, err
+	}
+	return QuerySelectorAll(top, exp), nil
+}
+
+// Query searches the XML Node that matches by the specified XPath expr,
+// and returns first matched element.
+func Query(top *Node, expr string) (*Node, error) {
+	exp, err := getQuery(expr)
+	if err != nil {
+		return nil, err
+	}
+	return QuerySelector(top, exp), nil
+}
+
+// QuerySelectorAll searches all of the XML Node that matches the specified
+// XPath selectors.
+func QuerySelectorAll(top *Node, selector *xpath.Expr) []*Node {
+	t := selector.Select(CreateXPathNavigator(top))
+	var elems []*Node
+	for t.MoveNext() {
+		elems = append(elems, getCurrentNode(t))
+	}
+	return elems
+}
+
+// QuerySelector returns the first matched XML Node by the specified XPath
+// selector.
+func QuerySelector(top *Node, selector *xpath.Expr) *Node {
+	t := selector.Select(CreateXPathNavigator(top))
+	if t.MoveNext() {
+		return getCurrentNode(t)
+	}
+	return nil
+}
+
+// FindEach searches the html.Node and calls functions cb.
+// Important: this method is deprecated, instead, use for .. = range Find(){}.
+func FindEach(top *Node, expr string, cb func(int, *Node)) {
+	for i, n := range Find(top, expr) {
+		cb(i, n)
+	}
+}
+
+// FindEachWithBreak functions the same as FindEach but allows to break the loop
+// by returning false from the callback function `cb`.
+// Important: this method is deprecated, instead, use .. = range Find(){}.
+func FindEachWithBreak(top *Node, expr string, cb func(int, *Node) bool) {
+	for i, n := range Find(top, expr) {
+		if !cb(i, n) {
+			break
+		}
+	}
+}
+
+type NodeNavigator struct {
+	root, curr *Node
+	attr       int
+}
+
+func (x *NodeNavigator) Current() *Node {
+	return x.curr
+}
+
+func (x *NodeNavigator) NodeType() xpath.NodeType {
+	switch x.curr.Type {
+	case CommentNode:
+		return xpath.CommentNode
+	case TextNode, CharDataNode:
+		return xpath.TextNode
+	case DeclarationNode, DocumentNode:
+		return xpath.RootNode
+	case ElementNode:
+		if x.attr != -1 {
+			return xpath.AttributeNode
+		}
+		return xpath.ElementNode
+	}
+	panic(fmt.Sprintf("unknown XML node type: %v", x.curr.Type))
+}
+
+func (x *NodeNavigator) LocalName() string {
+	if x.attr != -1 {
+		return x.curr.Attr[x.attr].Name.Local
+	}
+	return x.curr.Data
+
+}
+
+func (x *NodeNavigator) Prefix() string {
+	if x.NodeType() == xpath.AttributeNode {
+		if x.attr != -1 {
+			return x.curr.Attr[x.attr].Name.Space
+		}
+		return ""
+	}
+	return x.curr.Prefix
+}
+
+func (x *NodeNavigator) NamespaceURL() string {
+	if x.attr != -1 {
+		return x.curr.Attr[x.attr].NamespaceURI
+	}
+	return x.curr.NamespaceURI
+}
+
+func (x *NodeNavigator) Value() string {
+	switch x.curr.Type {
+	case CommentNode:
+		return x.curr.Data
+	case ElementNode:
+		if x.attr != -1 {
+			return x.curr.Attr[x.attr].Value
+		}
+		return x.curr.InnerText()
+	case TextNode:
+		return x.curr.Data
+	}
+	return ""
+}
+
+func (x *NodeNavigator) Copy() xpath.NodeNavigator {
+	n := *x
+	return &n
+}
+
+func (x *NodeNavigator) MoveToRoot() {
+	x.curr = x.root
+}
+
+func (x *NodeNavigator) MoveToParent() bool {
+	if x.attr != -1 {
+		x.attr = -1
+		return true
+	} else if node := x.curr.Parent; node != nil {
+		x.curr = node
+		return true
+	}
+	return false
+}
+
+func (x *NodeNavigator) MoveToNextAttribute() bool {
+	if x.attr >= len(x.curr.Attr)-1 {
+		return false
+	}
+	x.attr++
+	return true
+}
+
+func (x *NodeNavigator) MoveToChild() bool {
+	if x.attr != -1 {
+		return false
+	}
+	if node := x.curr.FirstChild; node != nil {
+		x.curr = node
+		return true
+	}
+	return false
+}
+
+func (x *NodeNavigator) MoveToFirst() bool {
+	if x.attr != -1 || x.curr.PrevSibling == nil {
+		return false
+	}
+	for {
+		node := x.curr.PrevSibling
+		if node == nil {
+			break
+		}
+		x.curr = node
+	}
+	return true
+}
+
+func (x *NodeNavigator) String() string {
+	return x.Value()
+}
+
+func (x *NodeNavigator) MoveToNext() bool {
+	if x.attr != -1 {
+		return false
+	}
+	for node := x.curr.NextSibling; node != nil; node = x.curr.NextSibling {
+		x.curr = node
+		if x.curr.Type != TextNode {
+			return true
+		}
+	}
+	return false
+}
+
+func (x *NodeNavigator) MoveToPrevious() bool {
+	if x.attr != -1 {
+		return false
+	}
+	for node := x.curr.PrevSibling; node != nil; node = x.curr.PrevSibling {
+		x.curr = node
+		if x.curr.Type != TextNode {
+			return true
+		}
+	}
+	return false
+}
+
+func (x *NodeNavigator) MoveTo(other xpath.NodeNavigator) bool {
+	node, ok := other.(*NodeNavigator)
+	if !ok || node.root != x.root {
+		return false
+	}
+
+	x.curr = node.curr
+	x.attr = node.attr
+	return true
+}

vendor/github.com/antchfx/xpath/.gitignore

@@ -0,0 +1,32 @@
+# vscode
+.vscode
+debug
+*.test
+
+./build
+
+# Compiled Object files, Static and Dynamic libs (Shared Objects)
+*.o
+*.a
+*.so
+
+
+# Folders
+_obj
+_test
+
+# Architecture specific extensions/prefixes
+*.[568vq]
+[568vq].out
+
+*.cgo1.go
+*.cgo2.c
+_cgo_defun.c
+_cgo_gotypes.go
+_cgo_export.*
+
+_testmain.go
+
+*.exe
+*.test
+*.prof

vendor/github.com/antchfx/xpath/.travis.yml

@@ -0,0 +1,12 @@
+language: go
+
+go:
+  - 1.6
+  - 1.9
+  - '1.10'
+
+install:
+  - go get github.com/mattn/goveralls
+
+script:
+  - $HOME/gopath/bin/goveralls -service=travis-ci

vendor/github.com/antchfx/xpath/LICENSE

@@ -0,0 +1,17 @@
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

vendor/github.com/antchfx/xpath/README.md

@@ -0,0 +1,172 @@
+XPath
+====
+[![GoDoc](https://godoc.org/github.com/antchfx/xpath?status.svg)](https://godoc.org/github.com/antchfx/xpath)
+[![Coverage Status](https://coveralls.io/repos/github/antchfx/xpath/badge.svg?branch=master)](https://coveralls.io/github/antchfx/xpath?branch=master)
+[![Build Status](https://travis-ci.org/antchfx/xpath.svg?branch=master)](https://travis-ci.org/antchfx/xpath)
+[![Go Report Card](https://goreportcard.com/badge/github.com/antchfx/xpath)](https://goreportcard.com/report/github.com/antchfx/xpath)
+
+XPath is Go package provides selecting nodes from XML, HTML or other documents using XPath expression.
+
+Implementation
+===
+
+- [htmlquery](https://github.com/antchfx/htmlquery) - an XPath query package for HTML document
+
+- [xmlquery](https://github.com/antchfx/xmlquery) - an XPath query package for XML document.
+
+- [jsonquery](https://github.com/antchfx/jsonquery) - an XPath query package for JSON document
+
+Supported Features
+===
+
+#### The basic XPath patterns.
+
+> The basic XPath patterns cover 90% of the cases that most stylesheets will need.
+
+- `node` : Selects all child elements with nodeName of node.
+
+- `*` : Selects all child elements.
+
+- `@attr` : Selects the attribute attr.
+
+- `@*` : Selects all attributes.
+
+- `node()` : Matches an org.w3c.dom.Node.
+
+- `text()` : Matches a org.w3c.dom.Text node.
+
+- `comment()` : Matches a comment.
+
+- `.` : Selects the current node.
+
+- `..` : Selects the parent of current node.
+
+- `/` : Selects the document node.
+
+- `a[expr]` : Select only those nodes matching a which also satisfy the expression expr.
+
+- `a[n]` : Selects the nth matching node matching a When a filter's expression is a number, XPath selects based on position.
+
+- `a/b` : For each node matching a, add the nodes matching b to the result.
+
+- `a//b` : For each node matching a, add the descendant nodes matching b to the result. 
+
+- `//b` : Returns elements in the entire document matching b.
+
+- `a|b` : All nodes matching a or b, union operation(not boolean or).
+
+- `(a, b, c)` : Evaluates each of its operands and concatenates the resulting sequences, in order, into a single result sequence
+
+
+#### Node Axes 
+
+- `child::*` : The child axis selects children of the current node.
+
+- `descendant::*` : The descendant axis selects descendants of the current node. It is equivalent to '//'.
+
+- `descendant-or-self::*` : Selects descendants including the current node.
+
+- `attribute::*` : Selects attributes of the current element. It is equivalent to @*
+
+- `following-sibling::*` : Selects nodes after the current node.
+
+- `preceding-sibling::*` : Selects nodes before the current node.
+
+- `following::*` : Selects the first matching node following in document order, excluding descendants. 
+
+- `preceding::*` : Selects the first matching node preceding in document order, excluding ancestors. 
+
+- `parent::*` : Selects the parent if it matches. The '..' pattern from the core is equivalent to 'parent::node()'.
+
+- `ancestor::*` : Selects matching ancestors.
+
+- `ancestor-or-self::*` : Selects ancestors including the current node.
+
+- `self::*` : Selects the current node. '.' is equivalent to 'self::node()'.
+
+#### Expressions
+
+ The gxpath supported three types: number, boolean, string.
+
+- `path` : Selects nodes based on the path.
+
+- `a = b` : Standard comparisons.
+
+    * a = b	    True if a equals b.
+    * a != b	True if a is not equal to b.
+    * a < b	    True if a is less than b.
+    * a <= b	True if a is less than or equal to b.
+    * a > b	    True if a is greater than b.
+    * a >= b	True if a is greater than or equal to b.
+
+- `a + b` : Arithmetic expressions.
+
+    * `- a`	Unary minus
+    * a + b	Add
+    * a - b	Substract
+    * a * b	Multiply
+    * a div b	Divide
+    * a mod b	Floating point mod, like Java.
+
+- `a or b` : Boolean `or` operation.
+
+- `a and b` : Boolean `and` operation.
+
+- `(expr)` : Parenthesized expressions.
+
+- `fun(arg1, ..., argn)` : Function calls:
+
+| Function | Supported |
+| --- | --- |
+`boolean()`| ✓ |
+`ceiling()`| ✓ |
+`choose()`| ✗ |
+`concat()`| ✓ |
+`contains()`| ✓ |
+`count()`| ✓ |
+`current()`| ✗ |
+`document()`| ✗ |
+`element-available()`| ✗ |
+`ends-with()`| ✓ |
+`false()`| ✓ |
+`floor()`| ✓ |
+`format-number()`| ✗ |
+`function-available()`| ✗ |
+`generate-id()`| ✗ |
+`id()`| ✗ |
+`key()`| ✗ |
+`lang()`| ✗ |
+`last()`| ✓ |
+`local-name()`| ✓ |
+`name()`| ✓ |
+`namespace-uri()`| ✓ |
+`normalize-space()`| ✓ |
+`not()`| ✓ |
+`number()`| ✓ |
+`position()`| ✓ |
+`replace()`| ✓ |
+`reverse()`| ✓ |
+`round()`| ✓ |
+`starts-with()`| ✓ |
+`string()`| ✓ |
+`string-length()`| ✓ |
+`substring()`| ✓ |
+`substring-after()`| ✓ |
+`substring-before()`| ✓ |
+`sum()`| ✓ |
+`system-property()`| ✗ |
+`translate()`| ✓ |
+`true()`| ✓ |
+`unparsed-entity-url()` | ✗ |
+
+Changelogs
+===
+
+2019-03-19 
+- optimize XPath `|` operation performance. [#33](https://github.com/antchfx/xpath/issues/33). Tips: suggest split into multiple subquery if you have a lot of `|` operations.
+
+2019-01-29
+-  improvement `normalize-space` function. [#32](https://github.com/antchfx/xpath/issues/32)
+
+2018-12-07
+-  supports XPath 2.0 Sequence expressions. [#30](https://github.com/antchfx/xpath/pull/30) by [@minherz](https://github.com/minherz).

vendor/github.com/antchfx/xpath/build.go

@@ -0,0 +1,522 @@
+package xpath
+
+import (
+	"errors"
+	"fmt"
+)
+
+type flag int
+
+const (
+	noneFlag flag = iota
+	filterFlag
+)
+
+// builder provides building an XPath expressions.
+type builder struct {
+	depth      int
+	flag       flag
+	firstInput query
+}
+
+// axisPredicate creates a predicate to predicating for this axis node.
+func axisPredicate(root *axisNode) func(NodeNavigator) bool {
+	// get current axix node type.
+	typ := ElementNode
+	switch root.AxeType {
+	case "attribute":
+		typ = AttributeNode
+	case "self", "parent":
+		typ = allNode
+	default:
+		switch root.Prop {
+		case "comment":
+			typ = CommentNode
+		case "text":
+			typ = TextNode
+			//	case "processing-instruction":
+		//	typ = ProcessingInstructionNode
+		case "node":
+			typ = allNode
+		}
+	}
+	nametest := root.LocalName != "" || root.Prefix != ""
+	predicate := func(n NodeNavigator) bool {
+		if typ == n.NodeType() || typ == allNode || typ == TextNode {
+			if nametest {
+				if root.LocalName == n.LocalName() && root.Prefix == n.Prefix() {
+					return true
+				}
+			} else {
+				return true
+			}
+		}
+		return false
+	}
+
+	return predicate
+}
+
+// processAxisNode processes a query for the XPath axis node.
+func (b *builder) processAxisNode(root *axisNode) (query, error) {
+	var (
+		err       error
+		qyInput   query
+		qyOutput  query
+		predicate = axisPredicate(root)
+	)
+
+	if root.Input == nil {
+		qyInput = &contextQuery{}
+	} else {
+		if root.AxeType == "child" && (root.Input.Type() == nodeAxis) {
+			if input := root.Input.(*axisNode); input.AxeType == "descendant-or-self" {
+				var qyGrandInput query
+				if input.Input != nil {
+					qyGrandInput, _ = b.processNode(input.Input)
+				} else {
+					qyGrandInput = &contextQuery{}
+				}
+				// fix #20: https://github.com/antchfx/htmlquery/issues/20
+				filter := func(n NodeNavigator) bool {
+					v := predicate(n)
+					switch root.Prop {
+					case "text":
+						v = v && n.NodeType() == TextNode
+					case "comment":
+						v = v && n.NodeType() == CommentNode
+					}
+					return v
+				}
+				qyOutput = &descendantQuery{Input: qyGrandInput, Predicate: filter, Self: true}
+				return qyOutput, nil
+			}
+		}
+		qyInput, err = b.processNode(root.Input)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	switch root.AxeType {
+	case "ancestor":
+		qyOutput = &ancestorQuery{Input: qyInput, Predicate: predicate}
+	case "ancestor-or-self":
+		qyOutput = &ancestorQuery{Input: qyInput, Predicate: predicate, Self: true}
+	case "attribute":
+		qyOutput = &attributeQuery{Input: qyInput, Predicate: predicate}
+	case "child":
+		filter := func(n NodeNavigator) bool {
+			v := predicate(n)
+			switch root.Prop {
+			case "text":
+				v = v && n.NodeType() == TextNode
+			case "node":
+				v = v && (n.NodeType() == ElementNode || n.NodeType() == TextNode)
+			case "comment":
+				v = v && n.NodeType() == CommentNode
+			}
+			return v
+		}
+		qyOutput = &childQuery{Input: qyInput, Predicate: filter}
+	case "descendant":
+		qyOutput = &descendantQuery{Input: qyInput, Predicate: predicate}
+	case "descendant-or-self":
+		qyOutput = &descendantQuery{Input: qyInput, Predicate: predicate, Self: true}
+	case "following":
+		qyOutput = &followingQuery{Input: qyInput, Predicate: predicate}
+	case "following-sibling":
+		qyOutput = &followingQuery{Input: qyInput, Predicate: predicate, Sibling: true}
+	case "parent":
+		qyOutput = &parentQuery{Input: qyInput, Predicate: predicate}
+	case "preceding":
+		qyOutput = &precedingQuery{Input: qyInput, Predicate: predicate}
+	case "preceding-sibling":
+		qyOutput = &precedingQuery{Input: qyInput, Predicate: predicate, Sibling: true}
+	case "self":
+		qyOutput = &selfQuery{Input: qyInput, Predicate: predicate}
+	case "namespace":
+		// haha,what will you do someting??
+	default:
+		err = fmt.Errorf("unknown axe type: %s", root.AxeType)
+		return nil, err
+	}
+	return qyOutput, nil
+}
+
+// processFilterNode builds query for the XPath filter predicate.
+func (b *builder) processFilterNode(root *filterNode) (query, error) {
+	b.flag |= filterFlag
+
+	qyInput, err := b.processNode(root.Input)
+	if err != nil {
+		return nil, err
+	}
+	qyCond, err := b.processNode(root.Condition)
+	if err != nil {
+		return nil, err
+	}
+	qyOutput := &filterQuery{Input: qyInput, Predicate: qyCond}
+	return qyOutput, nil
+}
+
+// processFunctionNode processes query for the XPath function node.
+func (b *builder) processFunctionNode(root *functionNode) (query, error) {
+	var qyOutput query
+	switch root.FuncName {
+	case "starts-with":
+		arg1, err := b.processNode(root.Args[0])
+		if err != nil {
+			return nil, err
+		}
+		arg2, err := b.processNode(root.Args[1])
+		if err != nil {
+			return nil, err
+		}
+		qyOutput = &functionQuery{Input: b.firstInput, Func: startwithFunc(arg1, arg2)}
+	case "ends-with":
+		arg1, err := b.processNode(root.Args[0])
+		if err != nil {
+			return nil, err
+		}
+		arg2, err := b.processNode(root.Args[1])
+		if err != nil {
+			return nil, err
+		}
+		qyOutput = &functionQuery{Input: b.firstInput, Func: endwithFunc(arg1, arg2)}
+	case "contains":
+		arg1, err := b.processNode(root.Args[0])
+		if err != nil {
+			return nil, err
+		}
+		arg2, err := b.processNode(root.Args[1])
+		if err != nil {
+			return nil, err
+		}
+
+		qyOutput = &functionQuery{Input: b.firstInput, Func: containsFunc(arg1, arg2)}
+	case "substring":
+		//substring( string , start [, length] )
+		if len(root.Args) < 2 {
+			return nil, errors.New("xpath: substring function must have at least two parameter")
+		}
+		var (
+			arg1, arg2, arg3 query
+			err              error
+		)
+		if arg1, err = b.processNode(root.Args[0]); err != nil {
+			return nil, err
+		}
+		if arg2, err = b.processNode(root.Args[1]); err != nil {
+			return nil, err
+		}
+		if len(root.Args) == 3 {
+			if arg3, err = b.processNode(root.Args[2]); err != nil {
+				return nil, err
+			}
+		}
+		qyOutput = &functionQuery{Input: b.firstInput, Func: substringFunc(arg1, arg2, arg3)}
+	case "substring-before", "substring-after":
+		//substring-xxxx( haystack, needle )
+		if len(root.Args) != 2 {
+			return nil, errors.New("xpath: substring-before function must have two parameters")
+		}
+		var (
+			arg1, arg2 query
+			err        error
+		)
+		if arg1, err = b.processNode(root.Args[0]); err != nil {
+			return nil, err
+		}
+		if arg2, err = b.processNode(root.Args[1]); err != nil {
+			return nil, err
+		}
+		qyOutput = &functionQuery{
+			Input: b.firstInput,
+			Func:  substringIndFunc(arg1, arg2, root.FuncName == "substring-after"),
+		}
+	case "string-length":
+		// string-length( [string] )
+		if len(root.Args) < 1 {
+			return nil, errors.New("xpath: string-length function must have at least one parameter")
+		}
+		arg1, err := b.processNode(root.Args[0])
+		if err != nil {
+			return nil, err
+		}
+		qyOutput = &functionQuery{Input: b.firstInput, Func: stringLengthFunc(arg1)}
+	case "normalize-space":
+		if len(root.Args) == 0 {
+			return nil, errors.New("xpath: normalize-space function must have at least one parameter")
+		}
+		argQuery, err := b.processNode(root.Args[0])
+		if err != nil {
+			return nil, err
+		}
+		qyOutput = &functionQuery{Input: argQuery, Func: normalizespaceFunc}
+	case "replace":
+		//replace( string , string, string )
+		if len(root.Args) != 3 {
+			return nil, errors.New("xpath: replace function must have three parameters")
+		}
+		var (
+			arg1, arg2, arg3 query
+			err              error
+		)
+		if arg1, err = b.processNode(root.Args[0]); err != nil {
+			return nil, err
+		}
+		if arg2, err = b.processNode(root.Args[1]); err != nil {
+			return nil, err
+		}
+		if arg3, err = b.processNode(root.Args[2]); err != nil {
+			return nil, err
+		}
+		qyOutput = &functionQuery{Input: b.firstInput, Func: replaceFunc(arg1, arg2, arg3)}
+	case "translate":
+		//translate( string , string, string )
+		if len(root.Args) != 3 {
+			return nil, errors.New("xpath: translate function must have three parameters")
+		}
+		var (
+			arg1, arg2, arg3 query
+			err              error
+		)
+		if arg1, err = b.processNode(root.Args[0]); err != nil {
+			return nil, err
+		}
+		if arg2, err = b.processNode(root.Args[1]); err != nil {
+			return nil, err
+		}
+		if arg3, err = b.processNode(root.Args[2]); err != nil {
+			return nil, err
+		}
+		qyOutput = &functionQuery{Input: b.firstInput, Func: translateFunc(arg1, arg2, arg3)}
+	case "not":
+		if len(root.Args) == 0 {
+			return nil, errors.New("xpath: not function must have at least one parameter")
+		}
+		argQuery, err := b.processNode(root.Args[0])
+		if err != nil {
+			return nil, err
+		}
+		qyOutput = &functionQuery{Input: argQuery, Func: notFunc}
+	case "name", "local-name", "namespace-uri":
+		if len(root.Args) > 1 {
+			return nil, fmt.Errorf("xpath: %s function must have at most one parameter", root.FuncName)
+		}
+		var (
+			arg query
+			err error
+		)
+		if len(root.Args) == 1 {
+			arg, err = b.processNode(root.Args[0])
+			if err != nil {
+				return nil, err
+			}
+		}
+		switch root.FuncName {
+		case "name":
+			qyOutput = &functionQuery{Input: b.firstInput, Func: nameFunc(arg)}
+		case "local-name":
+			qyOutput = &functionQuery{Input: b.firstInput, Func: localNameFunc(arg)}
+		case "namespace-uri":
+			qyOutput = &functionQuery{Input: b.firstInput, Func: namespaceFunc(arg)}
+		}
+	case "true", "false":
+		val := root.FuncName == "true"
+		qyOutput = &functionQuery{
+			Input: b.firstInput,
+			Func: func(_ query, _ iterator) interface{} {
+				return val
+			},
+		}
+	case "last":
+		qyOutput = &functionQuery{Input: b.firstInput, Func: lastFunc}
+	case "position":
+		qyOutput = &functionQuery{Input: b.firstInput, Func: positionFunc}
+	case "boolean", "number", "string":
+		inp := b.firstInput
+		if len(root.Args) > 1 {
+			return nil, fmt.Errorf("xpath: %s function must have at most one parameter", root.FuncName)
+		}
+		if len(root.Args) == 1 {
+			argQuery, err := b.processNode(root.Args[0])
+			if err != nil {
+				return nil, err
+			}
+			inp = argQuery
+		}
+		f := &functionQuery{Input: inp}
+		switch root.FuncName {
+		case "boolean":
+			f.Func = booleanFunc
+		case "string":
+			f.Func = stringFunc
+		case "number":
+			f.Func = numberFunc
+		}
+		qyOutput = f
+	case "count":
+		//if b.firstInput == nil {
+		//	return nil, errors.New("xpath: expression must evaluate to node-set")
+		//}
+		if len(root.Args) == 0 {
+			return nil, fmt.Errorf("xpath: count(node-sets) function must with have parameters node-sets")
+		}
+		argQuery, err := b.processNode(root.Args[0])
+		if err != nil {
+			return nil, err
+		}
+		qyOutput = &functionQuery{Input: argQuery, Func: countFunc}
+	case "sum":
+		if len(root.Args) == 0 {
+			return nil, fmt.Errorf("xpath: sum(node-sets) function must with have parameters node-sets")
+		}
+		argQuery, err := b.processNode(root.Args[0])
+		if err != nil {
+			return nil, err
+		}
+		qyOutput = &functionQuery{Input: argQuery, Func: sumFunc}
+	case "ceiling", "floor", "round":
+		if len(root.Args) == 0 {
+			return nil, fmt.Errorf("xpath: ceiling(node-sets) function must with have parameters node-sets")
+		}
+		argQuery, err := b.processNode(root.Args[0])
+		if err != nil {
+			return nil, err
+		}
+		f := &functionQuery{Input: argQuery}
+		switch root.FuncName {
+		case "ceiling":
+			f.Func = ceilingFunc
+		case "floor":
+			f.Func = floorFunc
+		case "round":
+			f.Func = roundFunc
+		}
+		qyOutput = f
+	case "concat":
+		if len(root.Args) < 2 {
+			return nil, fmt.Errorf("xpath: concat() must have at least two arguments")
+		}
+		var args []query
+		for _, v := range root.Args {
+			q, err := b.processNode(v)
+			if err != nil {
+				return nil, err
+			}
+			args = append(args, q)
+		}
+		qyOutput = &functionQuery{Input: b.firstInput, Func: concatFunc(args...)}
+	case "reverse":
+		if len(root.Args) == 0 {
+			return nil, fmt.Errorf("xpath: reverse(node-sets) function must with have parameters node-sets")
+		}
+		argQuery, err := b.processNode(root.Args[0])
+		if err != nil {
+			return nil, err
+		}
+		qyOutput = &transformFunctionQuery{Input: argQuery, Func: reverseFunc}
+	default:
+		return nil, fmt.Errorf("not yet support this function %s()", root.FuncName)
+	}
+	return qyOutput, nil
+}
+
+func (b *builder) processOperatorNode(root *operatorNode) (query, error) {
+	left, err := b.processNode(root.Left)
+	if err != nil {
+		return nil, err
+	}
+	right, err := b.processNode(root.Right)
+	if err != nil {
+		return nil, err
+	}
+	var qyOutput query
+	switch root.Op {
+	case "+", "-", "div", "mod": // Numeric operator
+		var exprFunc func(interface{}, interface{}) interface{}
+		switch root.Op {
+		case "+":
+			exprFunc = plusFunc
+		case "-":
+			exprFunc = minusFunc
+		case "div":
+			exprFunc = divFunc
+		case "mod":
+			exprFunc = modFunc
+		}
+		qyOutput = &numericQuery{Left: left, Right: right, Do: exprFunc}
+	case "=", ">", ">=", "<", "<=", "!=":
+		var exprFunc func(iterator, interface{}, interface{}) interface{}
+		switch root.Op {
+		case "=":
+			exprFunc = eqFunc
+		case ">":
+			exprFunc = gtFunc
+		case ">=":
+			exprFunc = geFunc
+		case "<":
+			exprFunc = ltFunc
+		case "<=":
+			exprFunc = leFunc
+		case "!=":
+			exprFunc = neFunc
+		}
+		qyOutput = &logicalQuery{Left: left, Right: right, Do: exprFunc}
+	case "or", "and":
+		isOr := false
+		if root.Op == "or" {
+			isOr = true
+		}
+		qyOutput = &booleanQuery{Left: left, Right: right, IsOr: isOr}
+	case "|":
+		qyOutput = &unionQuery{Left: left, Right: right}
+	}
+	return qyOutput, nil
+}
+
+func (b *builder) processNode(root node) (q query, err error) {
+	if b.depth = b.depth + 1; b.depth > 1024 {
+		err = errors.New("the xpath expressions is too complex")
+		return
+	}
+
+	switch root.Type() {
+	case nodeConstantOperand:
+		n := root.(*operandNode)
+		q = &constantQuery{Val: n.Val}
+	case nodeRoot:
+		q = &contextQuery{Root: true}
+	case nodeAxis:
+		q, err = b.processAxisNode(root.(*axisNode))
+		b.firstInput = q
+	case nodeFilter:
+		q, err = b.processFilterNode(root.(*filterNode))
+	case nodeFunction:
+		q, err = b.processFunctionNode(root.(*functionNode))
+	case nodeOperator:
+		q, err = b.processOperatorNode(root.(*operatorNode))
+	}
+	return
+}
+
+// build builds a specified XPath expressions expr.
+func build(expr string) (q query, err error) {
+	defer func() {
+		if e := recover(); e != nil {
+			switch x := e.(type) {
+			case string:
+				err = errors.New(x)
+			case error:
+				err = x
+			default:
+				err = errors.New("unknown panic")
+			}
+		}
+	}()
+	root := parse(expr)
+	b := &builder{}
+	return b.processNode(root)
+}

vendor/github.com/antchfx/xpath/func.go

@@ -0,0 +1,585 @@
+package xpath
+
+import (
+	"errors"
+	"fmt"
+	"math"
+	"strconv"
+	"strings"
+	"sync"
+	"unicode"
+)
+
+// Defined an interface of stringBuilder that compatible with 
+// strings.Builder(go 1.10) and bytes.Buffer(< go 1.10)
+type stringBuilder interface {
+	WriteRune(r rune) (n int, err error)
+	WriteString(s string) (int, error)
+	Reset()
+	Grow(n int)
+	String() string
+}
+
+var builderPool = sync.Pool{New: func() interface{} {
+	return newStringBuilder()
+}}
+
+// The XPath function list.
+
+func predicate(q query) func(NodeNavigator) bool {
+	type Predicater interface {
+		Test(NodeNavigator) bool
+	}
+	if p, ok := q.(Predicater); ok {
+		return p.Test
+	}
+	return func(NodeNavigator) bool { return true }
+}
+
+// positionFunc is a XPath Node Set functions position().
+func positionFunc(q query, t iterator) interface{} {
+	var (
+		count = 1
+		node  = t.Current().Copy()
+	)
+	test := predicate(q)
+	for node.MoveToPrevious() {
+		if test(node) {
+			count++
+		}
+	}
+	return float64(count)
+}
+
+// lastFunc is a XPath Node Set functions last().
+func lastFunc(q query, t iterator) interface{} {
+	var (
+		count = 0
+		node  = t.Current().Copy()
+	)
+	node.MoveToFirst()
+	test := predicate(q)
+	for {
+		if test(node) {
+			count++
+		}
+		if !node.MoveToNext() {
+			break
+		}
+	}
+	return float64(count)
+}
+
+// countFunc is a XPath Node Set functions count(node-set).
+func countFunc(q query, t iterator) interface{} {
+	var count = 0
+	q = functionArgs(q)
+	test := predicate(q)
+	switch typ := q.Evaluate(t).(type) {
+	case query:
+		for node := typ.Select(t); node != nil; node = typ.Select(t) {
+			if test(node) {
+				count++
+			}
+		}
+	}
+	return float64(count)
+}
+
+// sumFunc is a XPath Node Set functions sum(node-set).
+func sumFunc(q query, t iterator) interface{} {
+	var sum float64
+	switch typ := functionArgs(q).Evaluate(t).(type) {
+	case query:
+		for node := typ.Select(t); node != nil; node = typ.Select(t) {
+			if v, err := strconv.ParseFloat(node.Value(), 64); err == nil {
+				sum += v
+			}
+		}
+	case float64:
+		sum = typ
+	case string:
+		v, err := strconv.ParseFloat(typ, 64)
+		if err != nil {
+			panic(errors.New("sum() function argument type must be a node-set or number"))
+		}
+		sum = v
+	}
+	return sum
+}
+
+func asNumber(t iterator, o interface{}) float64 {
+	switch typ := o.(type) {
+	case query:
+		node := typ.Select(t)
+		if node == nil {
+			return float64(0)
+		}
+		if v, err := strconv.ParseFloat(node.Value(), 64); err == nil {
+			return v
+		}
+	case float64:
+		return typ
+	case string:
+		v, err := strconv.ParseFloat(typ, 64)
+		if err != nil {
+			panic(errors.New("ceiling() function argument type must be a node-set or number"))
+		}
+		return v
+	}
+	return 0
+}
+
+// ceilingFunc is a XPath Node Set functions ceiling(node-set).
+func ceilingFunc(q query, t iterator) interface{} {
+	val := asNumber(t, functionArgs(q).Evaluate(t))
+	return math.Ceil(val)
+}
+
+// floorFunc is a XPath Node Set functions floor(node-set).
+func floorFunc(q query, t iterator) interface{} {
+	val := asNumber(t, functionArgs(q).Evaluate(t))
+	return math.Floor(val)
+}
+
+// roundFunc is a XPath Node Set functions round(node-set).
+func roundFunc(q query, t iterator) interface{} {
+	val := asNumber(t, functionArgs(q).Evaluate(t))
+	//return math.Round(val)
+	return round(val)
+}
+
+// nameFunc is a XPath functions name([node-set]).
+func nameFunc(arg query) func(query, iterator) interface{} {
+	return func(q query, t iterator) interface{} {
+		var v NodeNavigator
+		if arg == nil {
+			v = t.Current()
+		} else {
+			v = arg.Select(t)
+			if v == nil {
+				return ""
+			}
+		}
+		ns := v.Prefix()
+		if ns == "" {
+			return v.LocalName()
+		}
+		return ns + ":" + v.LocalName()
+	}
+}
+
+// localNameFunc is a XPath functions local-name([node-set]).
+func localNameFunc(arg query) func(query, iterator) interface{} {
+	return func(q query, t iterator) interface{} {
+		var v NodeNavigator
+		if arg == nil {
+			v = t.Current()
+		} else {
+			v = arg.Select(t)
+			if v == nil {
+				return ""
+			}
+		}
+		return v.LocalName()
+	}
+}
+
+// namespaceFunc is a XPath functions namespace-uri([node-set]).
+func namespaceFunc(arg query) func(query, iterator) interface{} {
+	return func(q query, t iterator) interface{} {
+		var v NodeNavigator
+		if arg == nil {
+			v = t.Current()
+		} else {
+			// Get the first node in the node-set if specified.
+			v = arg.Select(t)
+			if v == nil {
+				return ""
+			}
+		}
+		// fix about namespace-uri() bug: https://github.com/antchfx/xmlquery/issues/22
+		// TODO: In the next version, add NamespaceURL() to the NodeNavigator interface.
+		type namespaceURL interface {
+			NamespaceURL() string
+		}
+		if f, ok := v.(namespaceURL); ok {
+			return f.NamespaceURL()
+		}
+		return v.Prefix()
+	}
+}
+
+func asBool(t iterator, v interface{}) bool {
+	switch v := v.(type) {
+	case nil:
+		return false
+	case *NodeIterator:
+		return v.MoveNext()
+	case bool:
+		return v
+	case float64:
+		return v != 0
+	case string:
+		return v != ""
+	case query:
+		return v.Select(t) != nil
+	default:
+		panic(fmt.Errorf("unexpected type: %T", v))
+	}
+}
+
+func asString(t iterator, v interface{}) string {
+	switch v := v.(type) {
+	case nil:
+		return ""
+	case bool:
+		if v {
+			return "true"
+		}
+		return "false"
+	case float64:
+		return strconv.FormatFloat(v, 'g', -1, 64)
+	case string:
+		return v
+	case query:
+		node := v.Select(t)
+		if node == nil {
+			return ""
+		}
+		return node.Value()
+	default:
+		panic(fmt.Errorf("unexpected type: %T", v))
+	}
+}
+
+// booleanFunc is a XPath functions boolean([node-set]).
+func booleanFunc(q query, t iterator) interface{} {
+	v := functionArgs(q).Evaluate(t)
+	return asBool(t, v)
+}
+
+// numberFunc is a XPath functions number([node-set]).
+func numberFunc(q query, t iterator) interface{} {
+	v := functionArgs(q).Evaluate(t)
+	return asNumber(t, v)
+}
+
+// stringFunc is a XPath functions string([node-set]).
+func stringFunc(q query, t iterator) interface{} {
+	v := functionArgs(q).Evaluate(t)
+	return asString(t, v)
+}
+
+// startwithFunc is a XPath functions starts-with(string, string).
+func startwithFunc(arg1, arg2 query) func(query, iterator) interface{} {
+	return func(q query, t iterator) interface{} {
+		var (
+			m, n string
+			ok   bool
+		)
+		switch typ := functionArgs(arg1).Evaluate(t).(type) {
+		case string:
+			m = typ
+		case query:
+			node := typ.Select(t)
+			if node == nil {
+				return false
+			}
+			m = node.Value()
+		default:
+			panic(errors.New("starts-with() function argument type must be string"))
+		}
+		n, ok = functionArgs(arg2).Evaluate(t).(string)
+		if !ok {
+			panic(errors.New("starts-with() function argument type must be string"))
+		}
+		return strings.HasPrefix(m, n)
+	}
+}
+
+// endwithFunc is a XPath functions ends-with(string, string).
+func endwithFunc(arg1, arg2 query) func(query, iterator) interface{} {
+	return func(q query, t iterator) interface{} {
+		var (
+			m, n string
+			ok   bool
+		)
+		switch typ := functionArgs(arg1).Evaluate(t).(type) {
+		case string:
+			m = typ
+		case query:
+			node := typ.Select(t)
+			if node == nil {
+				return false
+			}
+			m = node.Value()
+		default:
+			panic(errors.New("ends-with() function argument type must be string"))
+		}
+		n, ok = functionArgs(arg2).Evaluate(t).(string)
+		if !ok {
+			panic(errors.New("ends-with() function argument type must be string"))
+		}
+		return strings.HasSuffix(m, n)
+	}
+}
+
+// containsFunc is a XPath functions contains(string or @attr, string).
+func containsFunc(arg1, arg2 query) func(query, iterator) interface{} {
+	return func(q query, t iterator) interface{} {
+		var (
+			m, n string
+			ok   bool
+		)
+		switch typ := functionArgs(arg1).Evaluate(t).(type) {
+		case string:
+			m = typ
+		case query:
+			node := typ.Select(t)
+			if node == nil {
+				return false
+			}
+			m = node.Value()
+		default:
+			panic(errors.New("contains() function argument type must be string"))
+		}
+
+		n, ok = functionArgs(arg2).Evaluate(t).(string)
+		if !ok {
+			panic(errors.New("contains() function argument type must be string"))
+		}
+
+		return strings.Contains(m, n)
+	}
+}
+
+// normalizespaceFunc is XPath functions normalize-space(string?)
+func normalizespaceFunc(q query, t iterator) interface{} {
+	var m string
+	switch typ := functionArgs(q).Evaluate(t).(type) {
+	case string:
+		m = typ
+	case query:
+		node := typ.Select(t)
+		if node == nil {
+			return ""
+		}
+		m = node.Value()
+	}
+	var b = builderPool.Get().(stringBuilder)
+	b.Grow(len(m))
+
+	runeStr := []rune(strings.TrimSpace(m))
+	l := len(runeStr)
+	for i := range runeStr {
+		r := runeStr[i]
+		isSpace := unicode.IsSpace(r)
+		if !(isSpace && (i+1 < l && unicode.IsSpace(runeStr[i+1]))) {
+			if isSpace {
+				r = ' '
+			}
+			b.WriteRune(r)
+		}
+	}
+	result := b.String()
+	b.Reset()
+	builderPool.Put(b)
+
+	return result
+}
+
+// substringFunc is XPath functions substring function returns a part of a given string.
+func substringFunc(arg1, arg2, arg3 query) func(query, iterator) interface{} {
+	return func(q query, t iterator) interface{} {
+		var m string
+		switch typ := functionArgs(arg1).Evaluate(t).(type) {
+		case string:
+			m = typ
+		case query:
+			node := typ.Select(t)
+			if node == nil {
+				return ""
+			}
+			m = node.Value()
+		}
+
+		var start, length float64
+		var ok bool
+
+		if start, ok = functionArgs(arg2).Evaluate(t).(float64); !ok {
+			panic(errors.New("substring() function first argument type must be int"))
+		} else if start < 1 {
+			panic(errors.New("substring() function first argument type must be >= 1"))
+		}
+		start--
+		if arg3 != nil {
+			if length, ok = functionArgs(arg3).Evaluate(t).(float64); !ok {
+				panic(errors.New("substring() function second argument type must be int"))
+			}
+		}
+		if (len(m) - int(start)) < int(length) {
+			panic(errors.New("substring() function start and length argument out of range"))
+		}
+		if length > 0 {
+			return m[int(start):int(length+start)]
+		}
+		return m[int(start):]
+	}
+}
+
+// substringIndFunc is XPath functions substring-before/substring-after function returns a part of a given string.
+func substringIndFunc(arg1, arg2 query, after bool) func(query, iterator) interface{} {
+	return func(q query, t iterator) interface{} {
+		var str string
+		switch v := functionArgs(arg1).Evaluate(t).(type) {
+		case string:
+			str = v
+		case query:
+			node := v.Select(t)
+			if node == nil {
+				return ""
+			}
+			str = node.Value()
+		}
+		var word string
+		switch v := functionArgs(arg2).Evaluate(t).(type) {
+		case string:
+			word = v
+		case query:
+			node := v.Select(t)
+			if node == nil {
+				return ""
+			}
+			word = node.Value()
+		}
+		if word == "" {
+			return ""
+		}
+
+		i := strings.Index(str, word)
+		if i < 0 {
+			return ""
+		}
+		if after {
+			return str[i+len(word):]
+		}
+		return str[:i]
+	}
+}
+
+// stringLengthFunc is XPATH string-length( [string] ) function that returns a number
+// equal to the number of characters in a given string.
+func stringLengthFunc(arg1 query) func(query, iterator) interface{} {
+	return func(q query, t iterator) interface{} {
+		switch v := functionArgs(arg1).Evaluate(t).(type) {
+		case string:
+			return float64(len(v))
+		case query:
+			node := v.Select(t)
+			if node == nil {
+				break
+			}
+			return float64(len(node.Value()))
+		}
+		return float64(0)
+	}
+}
+
+// translateFunc is XPath functions translate() function returns a replaced string.
+func translateFunc(arg1, arg2, arg3 query) func(query, iterator) interface{} {
+	return func(q query, t iterator) interface{} {
+		str := asString(t, functionArgs(arg1).Evaluate(t))
+		src := asString(t, functionArgs(arg2).Evaluate(t))
+		dst := asString(t, functionArgs(arg3).Evaluate(t))
+
+		replace := make([]string, 0, len(src))
+		for i, s := range src {
+			d := ""
+			if i < len(dst) {
+				d = string(dst[i])
+			}
+			replace = append(replace, string(s), d)
+		}
+		return strings.NewReplacer(replace...).Replace(str)
+	}
+}
+
+// replaceFunc is XPath functions replace() function returns a replaced string.
+func replaceFunc(arg1, arg2, arg3 query) func(query, iterator) interface{} {
+	return func(q query, t iterator) interface{} {
+		str := asString(t, functionArgs(arg1).Evaluate(t))
+		src := asString(t, functionArgs(arg2).Evaluate(t))
+		dst := asString(t, functionArgs(arg3).Evaluate(t))
+
+		return strings.Replace(str, src, dst, -1)
+	}
+}
+
+// notFunc is XPATH functions not(expression) function operation.
+func notFunc(q query, t iterator) interface{} {
+	switch v := functionArgs(q).Evaluate(t).(type) {
+	case bool:
+		return !v
+	case query:
+		node := v.Select(t)
+		return node == nil
+	default:
+		return false
+	}
+}
+
+// concatFunc is the concat function concatenates two or more
+// strings and returns the resulting string.
+// concat( string1 , string2 [, stringn]* )
+func concatFunc(args ...query) func(query, iterator) interface{} {
+	return func(q query, t iterator) interface{} {
+		b := builderPool.Get().(stringBuilder)
+		for _, v := range args {
+			v = functionArgs(v)
+
+			switch v := v.Evaluate(t).(type) {
+			case string:
+				b.WriteString(v)
+			case query:
+				node := v.Select(t)
+				if node != nil {
+					b.WriteString(node.Value())
+				}
+			}
+		}
+		result := b.String()
+		b.Reset()
+		builderPool.Put(b)
+
+		return result
+	}
+}
+
+// https://github.com/antchfx/xpath/issues/43
+func functionArgs(q query) query {
+	if _, ok := q.(*functionQuery); ok {
+		return q
+	}
+	return q.Clone()
+}
+
+func reverseFunc(q query, t iterator) func() NodeNavigator {
+	var list []NodeNavigator
+	for {
+		node := q.Select(t)
+		if node == nil {
+			break
+		}
+		list = append(list, node.Copy())
+	}
+	i := len(list)
+	return func() NodeNavigator {
+		if i <= 0 {
+			return nil
+		}
+		i--
+		node := list[i]
+		return node
+	}
+}

vendor/github.com/antchfx/xpath/func_go110.go

@@ -0,0 +1,16 @@
+// +build go1.10
+
+package xpath
+
+import (
+	"math"
+	"strings"
+)
+
+func round(f float64) int {
+	return int(math.Round(f))
+}
+
+func newStringBuilder() stringBuilder{ 
+	return &strings.Builder{}
+}

vendor/github.com/antchfx/xpath/func_pre_go110.go

@@ -0,0 +1,22 @@
+// +build !go1.10
+
+package xpath
+
+import (
+	"bytes"
+	"math"
+)
+
+// math.Round() is supported by Go 1.10+,
+// This method just compatible for version <1.10.
+// https://github.com/golang/go/issues/20100
+func round(f float64) int {
+	if math.Abs(f) < 0.5 {
+		return 0
+	}
+	return int(f + math.Copysign(0.5, f))
+}
+
+func newStringBuilder() stringBuilder {
+	return &bytes.Buffer{}
+}

vendor/github.com/antchfx/xpath/operator.go

@@ -0,0 +1,305 @@
+package xpath
+
+import (
+	"fmt"
+	"reflect"
+	"strconv"
+)
+
+// The XPath number operator function list.
+
+// valueType is a return value type.
+type valueType int
+
+const (
+	booleanType valueType = iota
+	numberType
+	stringType
+	nodeSetType
+)
+
+func getValueType(i interface{}) valueType {
+	v := reflect.ValueOf(i)
+	switch v.Kind() {
+	case reflect.Float64:
+		return numberType
+	case reflect.String:
+		return stringType
+	case reflect.Bool:
+		return booleanType
+	default:
+		if _, ok := i.(query); ok {
+			return nodeSetType
+		}
+	}
+	panic(fmt.Errorf("xpath unknown value type: %v", v.Kind()))
+}
+
+type logical func(iterator, string, interface{}, interface{}) bool
+
+var logicalFuncs = [][]logical{
+	{cmpBooleanBoolean, nil, nil, nil},
+	{nil, cmpNumericNumeric, cmpNumericString, cmpNumericNodeSet},
+	{nil, cmpStringNumeric, cmpStringString, cmpStringNodeSet},
+	{nil, cmpNodeSetNumeric, cmpNodeSetString, cmpNodeSetNodeSet},
+}
+
+// number vs number
+func cmpNumberNumberF(op string, a, b float64) bool {
+	switch op {
+	case "=":
+		return a == b
+	case ">":
+		return a > b
+	case "<":
+		return a < b
+	case ">=":
+		return a >= b
+	case "<=":
+		return a <= b
+	case "!=":
+		return a != b
+	}
+	return false
+}
+
+// string vs string
+func cmpStringStringF(op string, a, b string) bool {
+	switch op {
+	case "=":
+		return a == b
+	case ">":
+		return a > b
+	case "<":
+		return a < b
+	case ">=":
+		return a >= b
+	case "<=":
+		return a <= b
+	case "!=":
+		return a != b
+	}
+	return false
+}
+
+func cmpBooleanBooleanF(op string, a, b bool) bool {
+	switch op {
+	case "or":
+		return a || b
+	case "and":
+		return a && b
+	}
+	return false
+}
+
+func cmpNumericNumeric(t iterator, op string, m, n interface{}) bool {
+	a := m.(float64)
+	b := n.(float64)
+	return cmpNumberNumberF(op, a, b)
+}
+
+func cmpNumericString(t iterator, op string, m, n interface{}) bool {
+	a := m.(float64)
+	b := n.(string)
+	num, err := strconv.ParseFloat(b, 64)
+	if err != nil {
+		panic(err)
+	}
+	return cmpNumberNumberF(op, a, num)
+}
+
+func cmpNumericNodeSet(t iterator, op string, m, n interface{}) bool {
+	a := m.(float64)
+	b := n.(query)
+
+	for {
+		node := b.Select(t)
+		if node == nil {
+			break
+		}
+		num, err := strconv.ParseFloat(node.Value(), 64)
+		if err != nil {
+			panic(err)
+		}
+		if cmpNumberNumberF(op, a, num) {
+			return true
+		}
+	}
+	return false
+}
+
+func cmpNodeSetNumeric(t iterator, op string, m, n interface{}) bool {
+	a := m.(query)
+	b := n.(float64)
+	for {
+		node := a.Select(t)
+		if node == nil {
+			break
+		}
+		num, err := strconv.ParseFloat(node.Value(), 64)
+		if err != nil {
+			panic(err)
+		}
+		if cmpNumberNumberF(op, num, b) {
+			return true
+		}
+	}
+	return false
+}
+
+func cmpNodeSetString(t iterator, op string, m, n interface{}) bool {
+	a := m.(query)
+	b := n.(string)
+	for {
+		node := a.Select(t)
+		if node == nil {
+			break
+		}
+		if cmpStringStringF(op, b, node.Value()) {
+			return true
+		}
+	}
+	return false
+}
+
+func cmpNodeSetNodeSet(t iterator, op string, m, n interface{}) bool {
+	a := m.(query)
+	b := n.(query)
+	x := a.Select(t)
+	if x == nil {
+		return false
+	}
+	y := b.Select(t)
+	if y == nil {
+		return false
+	}
+	return cmpStringStringF(op, x.Value(), y.Value())
+}
+
+func cmpStringNumeric(t iterator, op string, m, n interface{}) bool {
+	a := m.(string)
+	b := n.(float64)
+	num, err := strconv.ParseFloat(a, 64)
+	if err != nil {
+		panic(err)
+	}
+	return cmpNumberNumberF(op, b, num)
+}
+
+func cmpStringString(t iterator, op string, m, n interface{}) bool {
+	a := m.(string)
+	b := n.(string)
+	return cmpStringStringF(op, a, b)
+}
+
+func cmpStringNodeSet(t iterator, op string, m, n interface{}) bool {
+	a := m.(string)
+	b := n.(query)
+	for {
+		node := b.Select(t)
+		if node == nil {
+			break
+		}
+		if cmpStringStringF(op, a, node.Value()) {
+			return true
+		}
+	}
+	return false
+}
+
+func cmpBooleanBoolean(t iterator, op string, m, n interface{}) bool {
+	a := m.(bool)
+	b := n.(bool)
+	return cmpBooleanBooleanF(op, a, b)
+}
+
+// eqFunc is an `=` operator.
+func eqFunc(t iterator, m, n interface{}) interface{} {
+	t1 := getValueType(m)
+	t2 := getValueType(n)
+	return logicalFuncs[t1][t2](t, "=", m, n)
+}
+
+// gtFunc is an `>` operator.
+func gtFunc(t iterator, m, n interface{}) interface{} {
+	t1 := getValueType(m)
+	t2 := getValueType(n)
+	return logicalFuncs[t1][t2](t, ">", m, n)
+}
+
+// geFunc is an `>=` operator.
+func geFunc(t iterator, m, n interface{}) interface{} {
+	t1 := getValueType(m)
+	t2 := getValueType(n)
+	return logicalFuncs[t1][t2](t, ">=", m, n)
+}
+
+// ltFunc is an `<` operator.
+func ltFunc(t iterator, m, n interface{}) interface{} {
+	t1 := getValueType(m)
+	t2 := getValueType(n)
+	return logicalFuncs[t1][t2](t, "<", m, n)
+}
+
+// leFunc is an `<=` operator.
+func leFunc(t iterator, m, n interface{}) interface{} {
+	t1 := getValueType(m)
+	t2 := getValueType(n)
+	return logicalFuncs[t1][t2](t, "<=", m, n)
+}
+
+// neFunc is an `!=` operator.
+func neFunc(t iterator, m, n interface{}) interface{} {
+	t1 := getValueType(m)
+	t2 := getValueType(n)
+	return logicalFuncs[t1][t2](t, "!=", m, n)
+}
+
+// orFunc is an `or` operator.
+var orFunc = func(t iterator, m, n interface{}) interface{} {
+	t1 := getValueType(m)
+	t2 := getValueType(n)
+	return logicalFuncs[t1][t2](t, "or", m, n)
+}
+
+func numericExpr(m, n interface{}, cb func(float64, float64) float64) float64 {
+	typ := reflect.TypeOf(float64(0))
+	a := reflect.ValueOf(m).Convert(typ)
+	b := reflect.ValueOf(n).Convert(typ)
+	return cb(a.Float(), b.Float())
+}
+
+// plusFunc is an `+` operator.
+var plusFunc = func(m, n interface{}) interface{} {
+	return numericExpr(m, n, func(a, b float64) float64 {
+		return a + b
+	})
+}
+
+// minusFunc is an `-` operator.
+var minusFunc = func(m, n interface{}) interface{} {
+	return numericExpr(m, n, func(a, b float64) float64 {
+		return a - b
+	})
+}
+
+// mulFunc is an `*` operator.
+var mulFunc = func(m, n interface{}) interface{} {
+	return numericExpr(m, n, func(a, b float64) float64 {
+		return a * b
+	})
+}
+
+// divFunc is an `DIV` operator.
+var divFunc = func(m, n interface{}) interface{} {
+	return numericExpr(m, n, func(a, b float64) float64 {
+		return a / b
+	})
+}
+
+// modFunc is an 'MOD' operator.
+var modFunc = func(m, n interface{}) interface{} {
+	return numericExpr(m, n, func(a, b float64) float64 {
+		return float64(int(a) % int(b))
+	})
+}

vendor/github.com/antchfx/xpath/query.go

@@ -0,0 +1,923 @@
+package xpath
+
+import (
+	"bytes"
+	"fmt"
+	"hash/fnv"
+	"reflect"
+)
+
+type iterator interface {
+	Current() NodeNavigator
+}
+
+// An XPath query interface.
+type query interface {
+	// Select traversing iterator returns a query matched node NodeNavigator.
+	Select(iterator) NodeNavigator
+
+	// Evaluate evaluates query and returns values of the current query.
+	Evaluate(iterator) interface{}
+
+	Clone() query
+}
+
+// nopQuery is an empty query that always return nil for any query.
+type nopQuery struct {
+	query
+}
+
+func (nopQuery) Select(iterator) NodeNavigator { return nil }
+
+func (nopQuery) Evaluate(iterator) interface{} { return nil }
+
+func (nopQuery) Clone() query { return nopQuery{} }
+
+// contextQuery is returns current node on the iterator object query.
+type contextQuery struct {
+	count int
+	Root  bool // Moving to root-level node in the current context iterator.
+}
+
+func (c *contextQuery) Select(t iterator) (n NodeNavigator) {
+	if c.count == 0 {
+		c.count++
+		n = t.Current().Copy()
+		if c.Root {
+			n.MoveToRoot()
+		}
+	}
+	return n
+}
+
+func (c *contextQuery) Evaluate(iterator) interface{} {
+	c.count = 0
+	return c
+}
+
+func (c *contextQuery) Clone() query {
+	return &contextQuery{count: 0, Root: c.Root}
+}
+
+// ancestorQuery is an XPath ancestor node query.(ancestor::*|ancestor-self::*)
+type ancestorQuery struct {
+	iterator func() NodeNavigator
+
+	Self      bool
+	Input     query
+	Predicate func(NodeNavigator) bool
+}
+
+func (a *ancestorQuery) Select(t iterator) NodeNavigator {
+	for {
+		if a.iterator == nil {
+			node := a.Input.Select(t)
+			if node == nil {
+				return nil
+			}
+			first := true
+			node = node.Copy()
+			a.iterator = func() NodeNavigator {
+				if first && a.Self {
+					first = false
+					if a.Predicate(node) {
+						return node
+					}
+				}
+				for node.MoveToParent() {
+					if !a.Predicate(node) {
+						continue
+					}
+					return node
+				}
+				return nil
+			}
+		}
+
+		if node := a.iterator(); node != nil {
+			return node
+		}
+		a.iterator = nil
+	}
+}
+
+func (a *ancestorQuery) Evaluate(t iterator) interface{} {
+	a.Input.Evaluate(t)
+	a.iterator = nil
+	return a
+}
+
+func (a *ancestorQuery) Test(n NodeNavigator) bool {
+	return a.Predicate(n)
+}
+
+func (a *ancestorQuery) Clone() query {
+	return &ancestorQuery{Self: a.Self, Input: a.Input.Clone(), Predicate: a.Predicate}
+}
+
+// attributeQuery is an XPath attribute node query.(@*)
+type attributeQuery struct {
+	iterator func() NodeNavigator
+
+	Input     query
+	Predicate func(NodeNavigator) bool
+}
+
+func (a *attributeQuery) Select(t iterator) NodeNavigator {
+	for {
+		if a.iterator == nil {
+			node := a.Input.Select(t)
+			if node == nil {
+				return nil
+			}
+			node = node.Copy()
+			a.iterator = func() NodeNavigator {
+				for {
+					onAttr := node.MoveToNextAttribute()
+					if !onAttr {
+						return nil
+					}
+					if a.Predicate(node) {
+						return node
+					}
+				}
+			}
+		}
+
+		if node := a.iterator(); node != nil {
+			return node
+		}
+		a.iterator = nil
+	}
+}
+
+func (a *attributeQuery) Evaluate(t iterator) interface{} {
+	a.Input.Evaluate(t)
+	a.iterator = nil
+	return a
+}
+
+func (a *attributeQuery) Test(n NodeNavigator) bool {
+	return a.Predicate(n)
+}
+
+func (a *attributeQuery) Clone() query {
+	return &attributeQuery{Input: a.Input.Clone(), Predicate: a.Predicate}
+}
+
+// childQuery is an XPath child node query.(child::*)
+type childQuery struct {
+	posit    int
+	iterator func() NodeNavigator
+
+	Input     query
+	Predicate func(NodeNavigator) bool
+}
+
+func (c *childQuery) Select(t iterator) NodeNavigator {
+	for {
+		if c.iterator == nil {
+			c.posit = 0
+			node := c.Input.Select(t)
+			if node == nil {
+				return nil
+			}
+			node = node.Copy()
+			first := true
+			c.iterator = func() NodeNavigator {
+				for {
+					if (first && !node.MoveToChild()) || (!first && !node.MoveToNext()) {
+						return nil
+					}
+					first = false
+					if c.Predicate(node) {
+						return node
+					}
+				}
+			}
+		}
+
+		if node := c.iterator(); node != nil {
+			c.posit++
+			return node
+		}
+		c.iterator = nil
+	}
+}
+
+func (c *childQuery) Evaluate(t iterator) interface{} {
+	c.Input.Evaluate(t)
+	c.iterator = nil
+	return c
+}
+
+func (c *childQuery) Test(n NodeNavigator) bool {
+	return c.Predicate(n)
+}
+
+func (c *childQuery) Clone() query {
+	return &childQuery{Input: c.Input.Clone(), Predicate: c.Predicate}
+}
+
+// position returns a position of current NodeNavigator.
+func (c *childQuery) position() int {
+	return c.posit
+}
+
+// descendantQuery is an XPath descendant node query.(descendant::* | descendant-or-self::*)
+type descendantQuery struct {
+	iterator func() NodeNavigator
+	posit    int
+	level    int
+
+	Self      bool
+	Input     query
+	Predicate func(NodeNavigator) bool
+}
+
+func (d *descendantQuery) Select(t iterator) NodeNavigator {
+	for {
+		if d.iterator == nil {
+			d.posit = 0
+			node := d.Input.Select(t)
+			if node == nil {
+				return nil
+			}
+			node = node.Copy()
+			d.level = 0
+			positmap := make(map[int]int)
+			first := true
+			d.iterator = func() NodeNavigator {
+				if first && d.Self {
+					first = false
+					if d.Predicate(node) {
+						d.posit = 1
+						positmap[d.level] = 1
+						return node
+					}
+				}
+
+				for {
+					if node.MoveToChild() {
+						d.level = d.level + 1
+						positmap[d.level] = 0
+					} else {
+						for {
+							if d.level == 0 {
+								return nil
+							}
+							if node.MoveToNext() {
+								break
+							}
+							node.MoveToParent()
+							d.level = d.level - 1
+						}
+					}
+					if d.Predicate(node) {
+						positmap[d.level]++
+						d.posit = positmap[d.level]
+						return node
+					}
+				}
+			}
+		}
+
+		if node := d.iterator(); node != nil {
+			return node
+		}
+		d.iterator = nil
+	}
+}
+
+func (d *descendantQuery) Evaluate(t iterator) interface{} {
+	d.Input.Evaluate(t)
+	d.iterator = nil
+	return d
+}
+
+func (d *descendantQuery) Test(n NodeNavigator) bool {
+	return d.Predicate(n)
+}
+
+// position returns a position of current NodeNavigator.
+func (d *descendantQuery) position() int {
+	return d.posit
+}
+
+func (d *descendantQuery) depth() int {
+	return d.level
+}
+
+func (d *descendantQuery) Clone() query {
+	return &descendantQuery{Self: d.Self, Input: d.Input.Clone(), Predicate: d.Predicate}
+}
+
+// followingQuery is an XPath following node query.(following::*|following-sibling::*)
+type followingQuery struct {
+	posit    int
+	iterator func() NodeNavigator
+
+	Input     query
+	Sibling   bool // The matching sibling node of current node.
+	Predicate func(NodeNavigator) bool
+}
+
+func (f *followingQuery) Select(t iterator) NodeNavigator {
+	for {
+		if f.iterator == nil {
+			f.posit = 0
+			node := f.Input.Select(t)
+			if node == nil {
+				return nil
+			}
+			node = node.Copy()
+			if f.Sibling {
+				f.iterator = func() NodeNavigator {
+					for {
+						if !node.MoveToNext() {
+							return nil
+						}
+						if f.Predicate(node) {
+							f.posit++
+							return node
+						}
+					}
+				}
+			} else {
+				var q *descendantQuery // descendant query
+				f.iterator = func() NodeNavigator {
+					for {
+						if q == nil {
+							for !node.MoveToNext() {
+								if !node.MoveToParent() {
+									return nil
+								}
+							}
+							q = &descendantQuery{
+								Self:      true,
+								Input:     &contextQuery{},
+								Predicate: f.Predicate,
+							}
+							t.Current().MoveTo(node)
+						}
+						if node := q.Select(t); node != nil {
+							f.posit = q.posit
+							return node
+						}
+						q = nil
+					}
+				}
+			}
+		}
+
+		if node := f.iterator(); node != nil {
+			return node
+		}
+		f.iterator = nil
+	}
+}
+
+func (f *followingQuery) Evaluate(t iterator) interface{} {
+	f.Input.Evaluate(t)
+	return f
+}
+
+func (f *followingQuery) Test(n NodeNavigator) bool {
+	return f.Predicate(n)
+}
+
+func (f *followingQuery) Clone() query {
+	return &followingQuery{Input: f.Input.Clone(), Sibling: f.Sibling, Predicate: f.Predicate}
+}
+
+func (f *followingQuery) position() int {
+	return f.posit
+}
+
+// precedingQuery is an XPath preceding node query.(preceding::*)
+type precedingQuery struct {
+	iterator  func() NodeNavigator
+	posit     int
+	Input     query
+	Sibling   bool // The matching sibling node of current node.
+	Predicate func(NodeNavigator) bool
+}
+
+func (p *precedingQuery) Select(t iterator) NodeNavigator {
+	for {
+		if p.iterator == nil {
+			p.posit = 0
+			node := p.Input.Select(t)
+			if node == nil {
+				return nil
+			}
+			node = node.Copy()
+			if p.Sibling {
+				p.iterator = func() NodeNavigator {
+					for {
+						for !node.MoveToPrevious() {
+							return nil
+						}
+						if p.Predicate(node) {
+							p.posit++
+							return node
+						}
+					}
+				}
+			} else {
+				var q query
+				p.iterator = func() NodeNavigator {
+					for {
+						if q == nil {
+							for !node.MoveToPrevious() {
+								if !node.MoveToParent() {
+									return nil
+								}
+								p.posit = 0
+							}
+							q = &descendantQuery{
+								Self:      true,
+								Input:     &contextQuery{},
+								Predicate: p.Predicate,
+							}
+							t.Current().MoveTo(node)
+						}
+						if node := q.Select(t); node != nil {
+							p.posit++
+							return node
+						}
+						q = nil
+					}
+				}
+			}
+		}
+		if node := p.iterator(); node != nil {
+			return node
+		}
+		p.iterator = nil
+	}
+}
+
+func (p *precedingQuery) Evaluate(t iterator) interface{} {
+	p.Input.Evaluate(t)
+	return p
+}
+
+func (p *precedingQuery) Test(n NodeNavigator) bool {
+	return p.Predicate(n)
+}
+
+func (p *precedingQuery) Clone() query {
+	return &precedingQuery{Input: p.Input.Clone(), Sibling: p.Sibling, Predicate: p.Predicate}
+}
+
+func (p *precedingQuery) position() int {
+	return p.posit
+}
+
+// parentQuery is an XPath parent node query.(parent::*)
+type parentQuery struct {
+	Input     query
+	Predicate func(NodeNavigator) bool
+}
+
+func (p *parentQuery) Select(t iterator) NodeNavigator {
+	for {
+		node := p.Input.Select(t)
+		if node == nil {
+			return nil
+		}
+		node = node.Copy()
+		if node.MoveToParent() && p.Predicate(node) {
+			return node
+		}
+	}
+}
+
+func (p *parentQuery) Evaluate(t iterator) interface{} {
+	p.Input.Evaluate(t)
+	return p
+}
+
+func (p *parentQuery) Clone() query {
+	return &parentQuery{Input: p.Input.Clone(), Predicate: p.Predicate}
+}
+
+func (p *parentQuery) Test(n NodeNavigator) bool {
+	return p.Predicate(n)
+}
+
+// selfQuery is an Self node query.(self::*)
+type selfQuery struct {
+	Input     query
+	Predicate func(NodeNavigator) bool
+}
+
+func (s *selfQuery) Select(t iterator) NodeNavigator {
+	for {
+		node := s.Input.Select(t)
+		if node == nil {
+			return nil
+		}
+
+		if s.Predicate(node) {
+			return node
+		}
+	}
+}
+
+func (s *selfQuery) Evaluate(t iterator) interface{} {
+	s.Input.Evaluate(t)
+	return s
+}
+
+func (s *selfQuery) Test(n NodeNavigator) bool {
+	return s.Predicate(n)
+}
+
+func (s *selfQuery) Clone() query {
+	return &selfQuery{Input: s.Input.Clone(), Predicate: s.Predicate}
+}
+
+// filterQuery is an XPath query for predicate filter.
+type filterQuery struct {
+	Input     query
+	Predicate query
+	posit     int
+	positmap  map[int]int
+}
+
+func (f *filterQuery) do(t iterator) bool {
+	val := reflect.ValueOf(f.Predicate.Evaluate(t))
+	switch val.Kind() {
+	case reflect.Bool:
+		return val.Bool()
+	case reflect.String:
+		return len(val.String()) > 0
+	case reflect.Float64:
+		pt := getNodePosition(f.Input)
+		return int(val.Float()) == pt
+	default:
+		if q, ok := f.Predicate.(query); ok {
+			return q.Select(t) != nil
+		}
+	}
+	return false
+}
+
+func (f *filterQuery) position() int {
+	return f.posit
+}
+
+func (f *filterQuery) Select(t iterator) NodeNavigator {
+	if f.positmap == nil {
+		f.positmap = make(map[int]int)
+	}
+	for {
+
+		node := f.Input.Select(t)
+		if node == nil {
+			return node
+		}
+		node = node.Copy()
+
+		t.Current().MoveTo(node)
+		if f.do(t) {
+			// fix https://github.com/antchfx/htmlquery/issues/26
+			// Calculate and keep the each of matching node's position in the same depth.
+			level := getNodeDepth(f.Input)
+			f.positmap[level]++
+			f.posit = f.positmap[level]
+			return node
+		}
+	}
+}
+
+func (f *filterQuery) Evaluate(t iterator) interface{} {
+	f.Input.Evaluate(t)
+	return f
+}
+
+func (f *filterQuery) Clone() query {
+	return &filterQuery{Input: f.Input.Clone(), Predicate: f.Predicate.Clone()}
+}
+
+// functionQuery is an XPath function that returns a computed value for
+// the Evaluate call of the current NodeNavigator node. Select call isn't
+// applicable for functionQuery.
+type functionQuery struct {
+	Input query                             // Node Set
+	Func  func(query, iterator) interface{} // The xpath function.
+}
+
+func (f *functionQuery) Select(t iterator) NodeNavigator {
+	return nil
+}
+
+// Evaluate call a specified function that will returns the
+// following value type: number,string,boolean.
+func (f *functionQuery) Evaluate(t iterator) interface{} {
+	return f.Func(f.Input, t)
+}
+
+func (f *functionQuery) Clone() query {
+	return &functionQuery{Input: f.Input.Clone(), Func: f.Func}
+}
+
+// transformFunctionQuery diffs from functionQuery where the latter computes a scalar
+// value (number,string,boolean) for the current NodeNavigator node while the former
+// (transformFunctionQuery) performs a mapping or transform of the current NodeNavigator
+// and returns a new NodeNavigator. It is used for non-scalar XPath functions such as
+// reverse(), remove(), subsequence(), unordered(), etc.
+type transformFunctionQuery struct {
+	Input    query
+	Func     func(query, iterator) func() NodeNavigator
+	iterator func() NodeNavigator
+}
+
+func (f *transformFunctionQuery) Select(t iterator) NodeNavigator {
+	if f.iterator == nil {
+		f.iterator = f.Func(f.Input, t)
+	}
+	return f.iterator()
+}
+
+func (f *transformFunctionQuery) Evaluate(t iterator) interface{} {
+	f.Input.Evaluate(t)
+	f.iterator = nil
+	return f
+}
+
+func (f *transformFunctionQuery) Clone() query {
+	return &transformFunctionQuery{Input: f.Input.Clone(), Func: f.Func}
+}
+
+// constantQuery is an XPath constant operand.
+type constantQuery struct {
+	Val interface{}
+}
+
+func (c *constantQuery) Select(t iterator) NodeNavigator {
+	return nil
+}
+
+func (c *constantQuery) Evaluate(t iterator) interface{} {
+	return c.Val
+}
+
+func (c *constantQuery) Clone() query {
+	return c
+}
+
+// logicalQuery is an XPath logical expression.
+type logicalQuery struct {
+	Left, Right query
+
+	Do func(iterator, interface{}, interface{}) interface{}
+}
+
+func (l *logicalQuery) Select(t iterator) NodeNavigator {
+	// When a XPath expr is logical expression.
+	node := t.Current().Copy()
+	val := l.Evaluate(t)
+	switch val.(type) {
+	case bool:
+		if val.(bool) == true {
+			return node
+		}
+	}
+	return nil
+}
+
+func (l *logicalQuery) Evaluate(t iterator) interface{} {
+	m := l.Left.Evaluate(t)
+	n := l.Right.Evaluate(t)
+	return l.Do(t, m, n)
+}
+
+func (l *logicalQuery) Clone() query {
+	return &logicalQuery{Left: l.Left.Clone(), Right: l.Right.Clone(), Do: l.Do}
+}
+
+// numericQuery is an XPath numeric operator expression.
+type numericQuery struct {
+	Left, Right query
+
+	Do func(interface{}, interface{}) interface{}
+}
+
+func (n *numericQuery) Select(t iterator) NodeNavigator {
+	return nil
+}
+
+func (n *numericQuery) Evaluate(t iterator) interface{} {
+	m := n.Left.Evaluate(t)
+	k := n.Right.Evaluate(t)
+	return n.Do(m, k)
+}
+
+func (n *numericQuery) Clone() query {
+	return &numericQuery{Left: n.Left.Clone(), Right: n.Right.Clone(), Do: n.Do}
+}
+
+type booleanQuery struct {
+	IsOr        bool
+	Left, Right query
+	iterator    func() NodeNavigator
+}
+
+func (b *booleanQuery) Select(t iterator) NodeNavigator {
+	if b.iterator == nil {
+		var list []NodeNavigator
+		i := 0
+		root := t.Current().Copy()
+		if b.IsOr {
+			for {
+				node := b.Left.Select(t)
+				if node == nil {
+					break
+				}
+				node = node.Copy()
+				list = append(list, node)
+			}
+			t.Current().MoveTo(root)
+			for {
+				node := b.Right.Select(t)
+				if node == nil {
+					break
+				}
+				node = node.Copy()
+				list = append(list, node)
+			}
+		} else {
+			var m []NodeNavigator
+			var n []NodeNavigator
+			for {
+				node := b.Left.Select(t)
+				if node == nil {
+					break
+				}
+				node = node.Copy()
+				list = append(m, node)
+			}
+			t.Current().MoveTo(root)
+			for {
+				node := b.Right.Select(t)
+				if node == nil {
+					break
+				}
+				node = node.Copy()
+				list = append(n, node)
+			}
+			for _, k := range m {
+				for _, j := range n {
+					if k == j {
+						list = append(list, k)
+					}
+				}
+			}
+		}
+
+		b.iterator = func() NodeNavigator {
+			if i >= len(list) {
+				return nil
+			}
+			node := list[i]
+			i++
+			return node
+		}
+	}
+	return b.iterator()
+}
+
+func (b *booleanQuery) Evaluate(t iterator) interface{} {
+	m := b.Left.Evaluate(t)
+	left := asBool(t, m)
+	if b.IsOr && left {
+		return true
+	} else if !b.IsOr && !left {
+		return false
+	}
+	m = b.Right.Evaluate(t)
+	return asBool(t, m)
+}
+
+func (b *booleanQuery) Clone() query {
+	return &booleanQuery{IsOr: b.IsOr, Left: b.Left.Clone(), Right: b.Right.Clone()}
+}
+
+type unionQuery struct {
+	Left, Right query
+	iterator    func() NodeNavigator
+}
+
+func (u *unionQuery) Select(t iterator) NodeNavigator {
+	if u.iterator == nil {
+		var list []NodeNavigator
+		var m = make(map[uint64]bool)
+		root := t.Current().Copy()
+		for {
+			node := u.Left.Select(t)
+			if node == nil {
+				break
+			}
+			code := getHashCode(node.Copy())
+			if _, ok := m[code]; !ok {
+				m[code] = true
+				list = append(list, node.Copy())
+			}
+		}
+		t.Current().MoveTo(root)
+		for {
+			node := u.Right.Select(t)
+			if node == nil {
+				break
+			}
+			code := getHashCode(node.Copy())
+			if _, ok := m[code]; !ok {
+				m[code] = true
+				list = append(list, node.Copy())
+			}
+		}
+		var i int
+		u.iterator = func() NodeNavigator {
+			if i >= len(list) {
+				return nil
+			}
+			node := list[i]
+			i++
+			return node
+		}
+	}
+	return u.iterator()
+}
+
+func (u *unionQuery) Evaluate(t iterator) interface{} {
+	u.iterator = nil
+	u.Left.Evaluate(t)
+	u.Right.Evaluate(t)
+	return u
+}
+
+func (u *unionQuery) Clone() query {
+	return &unionQuery{Left: u.Left.Clone(), Right: u.Right.Clone()}
+}
+
+func getHashCode(n NodeNavigator) uint64 {
+	var sb bytes.Buffer
+	switch n.NodeType() {
+	case AttributeNode, TextNode, CommentNode:
+		sb.WriteString(fmt.Sprintf("%s=%s", n.LocalName(), n.Value()))
+		// https://github.com/antchfx/htmlquery/issues/25
+		d := 1
+		for n.MoveToPrevious() {
+			d++
+		}
+		sb.WriteString(fmt.Sprintf("-%d", d))
+		for n.MoveToParent() {
+			d = 1
+			for n.MoveToPrevious() {
+				d++
+			}
+			sb.WriteString(fmt.Sprintf("-%d", d))
+		}
+	case ElementNode:
+		sb.WriteString(n.Prefix() + n.LocalName())
+		d := 1
+		for n.MoveToPrevious() {
+			d++
+		}
+		sb.WriteString(fmt.Sprintf("-%d", d))
+
+		for n.MoveToParent() {
+			d = 1
+			for n.MoveToPrevious() {
+				d++
+			}
+			sb.WriteString(fmt.Sprintf("-%d", d))
+		}
+	}
+	h := fnv.New64a()
+	h.Write([]byte(sb.String()))
+	return h.Sum64()
+}
+
+func getNodePosition(q query) int {
+	type Position interface {
+		position() int
+	}
+	if count, ok := q.(Position); ok {
+		return count.position()
+	}
+	return 1
+}
+
+func getNodeDepth(q query) int {
+	type Depth interface {
+		depth() int
+	}
+	if count, ok := q.(Depth); ok {
+		return count.depth()
+	}
+	return 0
+}

vendor/github.com/antchfx/xpath/xpath.go

@@ -0,0 +1,161 @@
+package xpath
+
+import (
+	"errors"
+	"fmt"
+)
+
+// NodeType represents a type of XPath node.
+type NodeType int
+
+const (
+	// RootNode is a root node of the XML document or node tree.
+	RootNode NodeType = iota
+
+	// ElementNode is an element, such as <element>.
+	ElementNode
+
+	// AttributeNode is an attribute, such as id='123'.
+	AttributeNode
+
+	// TextNode is the text content of a node.
+	TextNode
+
+	// CommentNode is a comment node, such as <!-- my comment -->
+	CommentNode
+
+	// allNode is any types of node, used by xpath package only to predicate match.
+	allNode
+)
+
+// NodeNavigator provides cursor model for navigating XML data.
+type NodeNavigator interface {
+	// NodeType returns the XPathNodeType of the current node.
+	NodeType() NodeType
+
+	// LocalName gets the Name of the current node.
+	LocalName() string
+
+	// Prefix returns namespace prefix associated with the current node.
+	Prefix() string
+
+	// Value gets the value of current node.
+	Value() string
+
+	// Copy does a deep copy of the NodeNavigator and all its components.
+	Copy() NodeNavigator
+
+	// MoveToRoot moves the NodeNavigator to the root node of the current node.
+	MoveToRoot()
+
+	// MoveToParent moves the NodeNavigator to the parent node of the current node.
+	MoveToParent() bool
+
+	// MoveToNextAttribute moves the NodeNavigator to the next attribute on current node.
+	MoveToNextAttribute() bool
+
+	// MoveToChild moves the NodeNavigator to the first child node of the current node.
+	MoveToChild() bool
+
+	// MoveToFirst moves the NodeNavigator to the first sibling node of the current node.
+	MoveToFirst() bool
+
+	// MoveToNext moves the NodeNavigator to the next sibling node of the current node.
+	MoveToNext() bool
+
+	// MoveToPrevious moves the NodeNavigator to the previous sibling node of the current node.
+	MoveToPrevious() bool
+
+	// MoveTo moves the NodeNavigator to the same position as the specified NodeNavigator.
+	MoveTo(NodeNavigator) bool
+}
+
+// NodeIterator holds all matched Node object.
+type NodeIterator struct {
+	node  NodeNavigator
+	query query
+}
+
+// Current returns current node which matched.
+func (t *NodeIterator) Current() NodeNavigator {
+	return t.node
+}
+
+// MoveNext moves Navigator to the next match node.
+func (t *NodeIterator) MoveNext() bool {
+	n := t.query.Select(t)
+	if n != nil {
+		if !t.node.MoveTo(n) {
+			t.node = n.Copy()
+		}
+		return true
+	}
+	return false
+}
+
+// Select selects a node set using the specified XPath expression.
+// This method is deprecated, recommend using Expr.Select() method instead.
+func Select(root NodeNavigator, expr string) *NodeIterator {
+	exp, err := Compile(expr)
+	if err != nil {
+		panic(err)
+	}
+	return exp.Select(root)
+}
+
+// Expr is an XPath expression for query.
+type Expr struct {
+	s string
+	q query
+}
+
+type iteratorFunc func() NodeNavigator
+
+func (f iteratorFunc) Current() NodeNavigator {
+	return f()
+}
+
+// Evaluate returns the result of the expression.
+// The result type of the expression is one of the follow: bool,float64,string,NodeIterator).
+func (expr *Expr) Evaluate(root NodeNavigator) interface{} {
+	val := expr.q.Evaluate(iteratorFunc(func() NodeNavigator { return root }))
+	switch val.(type) {
+	case query:
+		return &NodeIterator{query: expr.q.Clone(), node: root}
+	}
+	return val
+}
+
+// Select selects a node set using the specified XPath expression.
+func (expr *Expr) Select(root NodeNavigator) *NodeIterator {
+	return &NodeIterator{query: expr.q.Clone(), node: root}
+}
+
+// String returns XPath expression string.
+func (expr *Expr) String() string {
+	return expr.s
+}
+
+// Compile compiles an XPath expression string.
+func Compile(expr string) (*Expr, error) {
+	if expr == "" {
+		return nil, errors.New("expr expression is nil")
+	}
+	qy, err := build(expr)
+	if err != nil {
+		return nil, err
+	}
+	if qy == nil {
+		return nil, fmt.Errorf(fmt.Sprintf("undeclared variable in XPath expression: %s", expr))
+	}
+	return &Expr{s: expr, q: qy}, nil
+}
+
+// MustCompile compiles an XPath expression string and ignored error.
+func MustCompile(expr string) *Expr {
+	exp, err := Compile(expr)
+	if err != nil {
+		return &Expr{s: expr, q: nopQuery{}}
+	}
+	return exp
+}

vendor/github.com/btcsuite/btcd/LICENSE

@@ -0,0 +1,16 @@
+ISC License
+
+Copyright (c) 2013-2017 The btcsuite developers
+Copyright (c) 2015-2016 The Decred developers
+
+Permission to use, copy, modify, and distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

vendor/github.com/btcsuite/btcd/btcec/README.md

@@ -0,0 +1,68 @@
+btcec
+=====
+
+[![Build Status](https://travis-ci.org/btcsuite/btcd.png?branch=master)](https://travis-ci.org/btcsuite/btcec)
+[![ISC License](http://img.shields.io/badge/license-ISC-blue.svg)](http://copyfree.org)
+[![GoDoc](https://godoc.org/github.com/btcsuite/btcd/btcec?status.png)](http://godoc.org/github.com/btcsuite/btcd/btcec)
+
+Package btcec implements elliptic curve cryptography needed for working with
+Bitcoin (secp256k1 only for now). It is designed so that it may be used with the
+standard crypto/ecdsa packages provided with go.  A comprehensive suite of test
+is provided to ensure proper functionality.  Package btcec was originally based
+on work from ThePiachu which is licensed under the same terms as Go, but it has
+signficantly diverged since then.  The btcsuite developers original is licensed
+under the liberal ISC license.
+
+Although this package was primarily written for btcd, it has intentionally been
+designed so it can be used as a standalone package for any projects needing to
+use secp256k1 elliptic curve cryptography.
+
+## Installation and Updating
+
+```bash
+$ go get -u github.com/btcsuite/btcd/btcec
+```
+
+## Examples
+
+* [Sign Message](http://godoc.org/github.com/btcsuite/btcd/btcec#example-package--SignMessage)  
+  Demonstrates signing a message with a secp256k1 private key that is first
+  parsed form raw bytes and serializing the generated signature.
+
+* [Verify Signature](http://godoc.org/github.com/btcsuite/btcd/btcec#example-package--VerifySignature)  
+  Demonstrates verifying a secp256k1 signature against a public key that is
+  first parsed from raw bytes.  The signature is also parsed from raw bytes.
+
+* [Encryption](http://godoc.org/github.com/btcsuite/btcd/btcec#example-package--EncryptMessage)
+  Demonstrates encrypting a message for a public key that is first parsed from
+  raw bytes, then decrypting it using the corresponding private key.
+
+* [Decryption](http://godoc.org/github.com/btcsuite/btcd/btcec#example-package--DecryptMessage)
+  Demonstrates decrypting a message using a private key that is first parsed
+  from raw bytes.
+
+## GPG Verification Key
+
+All official release tags are signed by Conformal so users can ensure the code
+has not been tampered with and is coming from the btcsuite developers.  To
+verify the signature perform the following:
+
+- Download the public key from the Conformal website at
+  https://opensource.conformal.com/GIT-GPG-KEY-conformal.txt
+
+- Import the public key into your GPG keyring:
+  ```bash
+  gpg --import GIT-GPG-KEY-conformal.txt
+  ```
+
+- Verify the release tag with the following command where `TAG_NAME` is a
+  placeholder for the specific tag:
+  ```bash
+  git tag -v TAG_NAME
+  ```
+
+## License
+
+Package btcec is licensed under the [copyfree](http://copyfree.org) ISC License
+except for btcec.go and btcec_test.go which is under the same license as Go.
+

vendor/github.com/btcsuite/btcd/btcec/btcec.go

@@ -0,0 +1,976 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Copyright 2011 ThePiachu. All rights reserved.
+// Copyright 2013-2014 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package btcec
+
+// References:
+//   [SECG]: Recommended Elliptic Curve Domain Parameters
+//     http://www.secg.org/sec2-v2.pdf
+//
+//   [GECC]: Guide to Elliptic Curve Cryptography (Hankerson, Menezes, Vanstone)
+
+// This package operates, internally, on Jacobian coordinates. For a given
+// (x, y) position on the curve, the Jacobian coordinates are (x1, y1, z1)
+// where x = x1/z1² and y = y1/z1³. The greatest speedups come when the whole
+// calculation can be performed within the transform (as in ScalarMult and
+// ScalarBaseMult). But even for Add and Double, it's faster to apply and
+// reverse the transform than to operate in affine coordinates.
+
+import (
+	"crypto/elliptic"
+	"math/big"
+	"sync"
+)
+
+var (
+	// fieldOne is simply the integer 1 in field representation.  It is
+	// used to avoid needing to create it multiple times during the internal
+	// arithmetic.
+	fieldOne = new(fieldVal).SetInt(1)
+)
+
+// KoblitzCurve supports a koblitz curve implementation that fits the ECC Curve
+// interface from crypto/elliptic.
+type KoblitzCurve struct {
+	*elliptic.CurveParams
+
+	// q is the value (P+1)/4 used to compute the square root of field
+	// elements.
+	q *big.Int
+
+	H         int      // cofactor of the curve.
+	halfOrder *big.Int // half the order N
+
+	// fieldB is the constant B of the curve as a fieldVal.
+	fieldB *fieldVal
+
+	// byteSize is simply the bit size / 8 and is provided for convenience
+	// since it is calculated repeatedly.
+	byteSize int
+
+	// bytePoints
+	bytePoints *[32][256][3]fieldVal
+
+	// The next 6 values are used specifically for endomorphism
+	// optimizations in ScalarMult.
+
+	// lambda must fulfill lambda^3 = 1 mod N where N is the order of G.
+	lambda *big.Int
+
+	// beta must fulfill beta^3 = 1 mod P where P is the prime field of the
+	// curve.
+	beta *fieldVal
+
+	// See the EndomorphismVectors in gensecp256k1.go to see how these are
+	// derived.
+	a1 *big.Int
+	b1 *big.Int
+	a2 *big.Int
+	b2 *big.Int
+}
+
+// Params returns the parameters for the curve.
+func (curve *KoblitzCurve) Params() *elliptic.CurveParams {
+	return curve.CurveParams
+}
+
+// bigAffineToField takes an affine point (x, y) as big integers and converts
+// it to an affine point as field values.
+func (curve *KoblitzCurve) bigAffineToField(x, y *big.Int) (*fieldVal, *fieldVal) {
+	x3, y3 := new(fieldVal), new(fieldVal)
+	x3.SetByteSlice(x.Bytes())
+	y3.SetByteSlice(y.Bytes())
+
+	return x3, y3
+}
+
+// fieldJacobianToBigAffine takes a Jacobian point (x, y, z) as field values and
+// converts it to an affine point as big integers.
+func (curve *KoblitzCurve) fieldJacobianToBigAffine(x, y, z *fieldVal) (*big.Int, *big.Int) {
+	// Inversions are expensive and both point addition and point doubling
+	// are faster when working with points that have a z value of one.  So,
+	// if the point needs to be converted to affine, go ahead and normalize
+	// the point itself at the same time as the calculation is the same.
+	var zInv, tempZ fieldVal
+	zInv.Set(z).Inverse()   // zInv = Z^-1
+	tempZ.SquareVal(&zInv)  // tempZ = Z^-2
+	x.Mul(&tempZ)           // X = X/Z^2 (mag: 1)
+	y.Mul(tempZ.Mul(&zInv)) // Y = Y/Z^3 (mag: 1)
+	z.SetInt(1)             // Z = 1 (mag: 1)
+
+	// Normalize the x and y values.
+	x.Normalize()
+	y.Normalize()
+
+	// Convert the field values for the now affine point to big.Ints.
+	x3, y3 := new(big.Int), new(big.Int)
+	x3.SetBytes(x.Bytes()[:])
+	y3.SetBytes(y.Bytes()[:])
+	return x3, y3
+}
+
+// IsOnCurve returns boolean if the point (x,y) is on the curve.
+// Part of the elliptic.Curve interface. This function differs from the
+// crypto/elliptic algorithm since a = 0 not -3.
+func (curve *KoblitzCurve) IsOnCurve(x, y *big.Int) bool {
+	// Convert big ints to field values for faster arithmetic.
+	fx, fy := curve.bigAffineToField(x, y)
+
+	// Elliptic curve equation for secp256k1 is: y^2 = x^3 + 7
+	y2 := new(fieldVal).SquareVal(fy).Normalize()
+	result := new(fieldVal).SquareVal(fx).Mul(fx).AddInt(7).Normalize()
+	return y2.Equals(result)
+}
+
+// addZ1AndZ2EqualsOne adds two Jacobian points that are already known to have
+// z values of 1 and stores the result in (x3, y3, z3).  That is to say
+// (x1, y1, 1) + (x2, y2, 1) = (x3, y3, z3).  It performs faster addition than
+// the generic add routine since less arithmetic is needed due to the ability to
+// avoid the z value multiplications.
+func (curve *KoblitzCurve) addZ1AndZ2EqualsOne(x1, y1, z1, x2, y2, x3, y3, z3 *fieldVal) {
+	// To compute the point addition efficiently, this implementation splits
+	// the equation into intermediate elements which are used to minimize
+	// the number of field multiplications using the method shown at:
+	// http://hyperelliptic.org/EFD/g1p/auto-shortw-jacobian-0.html#addition-mmadd-2007-bl
+	//
+	// In particular it performs the calculations using the following:
+	// H = X2-X1, HH = H^2, I = 4*HH, J = H*I, r = 2*(Y2-Y1), V = X1*I
+	// X3 = r^2-J-2*V, Y3 = r*(V-X3)-2*Y1*J, Z3 = 2*H
+	//
+	// This results in a cost of 4 field multiplications, 2 field squarings,
+	// 6 field additions, and 5 integer multiplications.
+
+	// When the x coordinates are the same for two points on the curve, the
+	// y coordinates either must be the same, in which case it is point
+	// doubling, or they are opposite and the result is the point at
+	// infinity per the group law for elliptic curve cryptography.
+	x1.Normalize()
+	y1.Normalize()
+	x2.Normalize()
+	y2.Normalize()
+	if x1.Equals(x2) {
+		if y1.Equals(y2) {
+			// Since x1 == x2 and y1 == y2, point doubling must be
+			// done, otherwise the addition would end up dividing
+			// by zero.
+			curve.doubleJacobian(x1, y1, z1, x3, y3, z3)
+			return
+		}
+
+		// Since x1 == x2 and y1 == -y2, the sum is the point at
+		// infinity per the group law.
+		x3.SetInt(0)
+		y3.SetInt(0)
+		z3.SetInt(0)
+		return
+	}
+
+	// Calculate X3, Y3, and Z3 according to the intermediate elements
+	// breakdown above.
+	var h, i, j, r, v fieldVal
+	var negJ, neg2V, negX3 fieldVal
+	h.Set(x1).Negate(1).Add(x2)                // H = X2-X1 (mag: 3)
+	i.SquareVal(&h).MulInt(4)                  // I = 4*H^2 (mag: 4)
+	j.Mul2(&h, &i)                             // J = H*I (mag: 1)
+	r.Set(y1).Negate(1).Add(y2).MulInt(2)      // r = 2*(Y2-Y1) (mag: 6)
+	v.Mul2(x1, &i)                             // V = X1*I (mag: 1)
+	negJ.Set(&j).Negate(1)                     // negJ = -J (mag: 2)
+	neg2V.Set(&v).MulInt(2).Negate(2)          // neg2V = -(2*V) (mag: 3)
+	x3.Set(&r).Square().Add(&negJ).Add(&neg2V) // X3 = r^2-J-2*V (mag: 6)
+	negX3.Set(x3).Negate(6)                    // negX3 = -X3 (mag: 7)
+	j.Mul(y1).MulInt(2).Negate(2)              // J = -(2*Y1*J) (mag: 3)
+	y3.Set(&v).Add(&negX3).Mul(&r).Add(&j)     // Y3 = r*(V-X3)-2*Y1*J (mag: 4)
+	z3.Set(&h).MulInt(2)                       // Z3 = 2*H (mag: 6)
+
+	// Normalize the resulting field values to a magnitude of 1 as needed.
+	x3.Normalize()
+	y3.Normalize()
+	z3.Normalize()
+}
+
+// addZ1EqualsZ2 adds two Jacobian points that are already known to have the
+// same z value and stores the result in (x3, y3, z3).  That is to say
+// (x1, y1, z1) + (x2, y2, z1) = (x3, y3, z3).  It performs faster addition than
+// the generic add routine since less arithmetic is needed due to the known
+// equivalence.
+func (curve *KoblitzCurve) addZ1EqualsZ2(x1, y1, z1, x2, y2, x3, y3, z3 *fieldVal) {
+	// To compute the point addition efficiently, this implementation splits
+	// the equation into intermediate elements which are used to minimize
+	// the number of field multiplications using a slightly modified version
+	// of the method shown at:
+	// http://hyperelliptic.org/EFD/g1p/auto-shortw-jacobian-0.html#addition-mmadd-2007-bl
+	//
+	// In particular it performs the calculations using the following:
+	// A = X2-X1, B = A^2, C=Y2-Y1, D = C^2, E = X1*B, F = X2*B
+	// X3 = D-E-F, Y3 = C*(E-X3)-Y1*(F-E), Z3 = Z1*A
+	//
+	// This results in a cost of 5 field multiplications, 2 field squarings,
+	// 9 field additions, and 0 integer multiplications.
+
+	// When the x coordinates are the same for two points on the curve, the
+	// y coordinates either must be the same, in which case it is point
+	// doubling, or they are opposite and the result is the point at
+	// infinity per the group law for elliptic curve cryptography.
+	x1.Normalize()
+	y1.Normalize()
+	x2.Normalize()
+	y2.Normalize()
+	if x1.Equals(x2) {
+		if y1.Equals(y2) {
+			// Since x1 == x2 and y1 == y2, point doubling must be
+			// done, otherwise the addition would end up dividing
+			// by zero.
+			curve.doubleJacobian(x1, y1, z1, x3, y3, z3)
+			return
+		}
+
+		// Since x1 == x2 and y1 == -y2, the sum is the point at
+		// infinity per the group law.
+		x3.SetInt(0)
+		y3.SetInt(0)
+		z3.SetInt(0)
+		return
+	}
+
+	// Calculate X3, Y3, and Z3 according to the intermediate elements
+	// breakdown above.
+	var a, b, c, d, e, f fieldVal
+	var negX1, negY1, negE, negX3 fieldVal
+	negX1.Set(x1).Negate(1)                // negX1 = -X1 (mag: 2)
+	negY1.Set(y1).Negate(1)                // negY1 = -Y1 (mag: 2)
+	a.Set(&negX1).Add(x2)                  // A = X2-X1 (mag: 3)
+	b.SquareVal(&a)                        // B = A^2 (mag: 1)
+	c.Set(&negY1).Add(y2)                  // C = Y2-Y1 (mag: 3)
+	d.SquareVal(&c)                        // D = C^2 (mag: 1)
+	e.Mul2(x1, &b)                         // E = X1*B (mag: 1)
+	negE.Set(&e).Negate(1)                 // negE = -E (mag: 2)
+	f.Mul2(x2, &b)                         // F = X2*B (mag: 1)
+	x3.Add2(&e, &f).Negate(3).Add(&d)      // X3 = D-E-F (mag: 5)
+	negX3.Set(x3).Negate(5).Normalize()    // negX3 = -X3 (mag: 1)
+	y3.Set(y1).Mul(f.Add(&negE)).Negate(3) // Y3 = -(Y1*(F-E)) (mag: 4)
+	y3.Add(e.Add(&negX3).Mul(&c))          // Y3 = C*(E-X3)+Y3 (mag: 5)
+	z3.Mul2(z1, &a)                        // Z3 = Z1*A (mag: 1)
+
+	// Normalize the resulting field values to a magnitude of 1 as needed.
+	x3.Normalize()
+	y3.Normalize()
+}
+
+// addZ2EqualsOne adds two Jacobian points when the second point is already
+// known to have a z value of 1 (and the z value for the first point is not 1)
+// and stores the result in (x3, y3, z3).  That is to say (x1, y1, z1) +
+// (x2, y2, 1) = (x3, y3, z3).  It performs faster addition than the generic
+// add routine since less arithmetic is needed due to the ability to avoid
+// multiplications by the second point's z value.
+func (curve *KoblitzCurve) addZ2EqualsOne(x1, y1, z1, x2, y2, x3, y3, z3 *fieldVal) {
+	// To compute the point addition efficiently, this implementation splits
+	// the equation into intermediate elements which are used to minimize
+	// the number of field multiplications using the method shown at:
+	// http://hyperelliptic.org/EFD/g1p/auto-shortw-jacobian-0.html#addition-madd-2007-bl
+	//
+	// In particular it performs the calculations using the following:
+	// Z1Z1 = Z1^2, U2 = X2*Z1Z1, S2 = Y2*Z1*Z1Z1, H = U2-X1, HH = H^2,
+	// I = 4*HH, J = H*I, r = 2*(S2-Y1), V = X1*I
+	// X3 = r^2-J-2*V, Y3 = r*(V-X3)-2*Y1*J, Z3 = (Z1+H)^2-Z1Z1-HH
+	//
+	// This results in a cost of 7 field multiplications, 4 field squarings,
+	// 9 field additions, and 4 integer multiplications.
+
+	// When the x coordinates are the same for two points on the curve, the
+	// y coordinates either must be the same, in which case it is point
+	// doubling, or they are opposite and the result is the point at
+	// infinity per the group law for elliptic curve cryptography.  Since
+	// any number of Jacobian coordinates can represent the same affine
+	// point, the x and y values need to be converted to like terms.  Due to
+	// the assumption made for this function that the second point has a z
+	// value of 1 (z2=1), the first point is already "converted".
+	var z1z1, u2, s2 fieldVal
+	x1.Normalize()
+	y1.Normalize()
+	z1z1.SquareVal(z1)                        // Z1Z1 = Z1^2 (mag: 1)
+	u2.Set(x2).Mul(&z1z1).Normalize()         // U2 = X2*Z1Z1 (mag: 1)
+	s2.Set(y2).Mul(&z1z1).Mul(z1).Normalize() // S2 = Y2*Z1*Z1Z1 (mag: 1)
+	if x1.Equals(&u2) {
+		if y1.Equals(&s2) {
+			// Since x1 == x2 and y1 == y2, point doubling must be
+			// done, otherwise the addition would end up dividing
+			// by zero.
+			curve.doubleJacobian(x1, y1, z1, x3, y3, z3)
+			return
+		}
+
+		// Since x1 == x2 and y1 == -y2, the sum is the point at
+		// infinity per the group law.
+		x3.SetInt(0)
+		y3.SetInt(0)
+		z3.SetInt(0)
+		return
+	}
+
+	// Calculate X3, Y3, and Z3 according to the intermediate elements
+	// breakdown above.
+	var h, hh, i, j, r, rr, v fieldVal
+	var negX1, negY1, negX3 fieldVal
+	negX1.Set(x1).Negate(1)                // negX1 = -X1 (mag: 2)
+	h.Add2(&u2, &negX1)                    // H = U2-X1 (mag: 3)
+	hh.SquareVal(&h)                       // HH = H^2 (mag: 1)
+	i.Set(&hh).MulInt(4)                   // I = 4 * HH (mag: 4)
+	j.Mul2(&h, &i)                         // J = H*I (mag: 1)
+	negY1.Set(y1).Negate(1)                // negY1 = -Y1 (mag: 2)
+	r.Set(&s2).Add(&negY1).MulInt(2)       // r = 2*(S2-Y1) (mag: 6)
+	rr.SquareVal(&r)                       // rr = r^2 (mag: 1)
+	v.Mul2(x1, &i)                         // V = X1*I (mag: 1)
+	x3.Set(&v).MulInt(2).Add(&j).Negate(3) // X3 = -(J+2*V) (mag: 4)
+	x3.Add(&rr)                            // X3 = r^2+X3 (mag: 5)
+	negX3.Set(x3).Negate(5)                // negX3 = -X3 (mag: 6)
+	y3.Set(y1).Mul(&j).MulInt(2).Negate(2) // Y3 = -(2*Y1*J) (mag: 3)
+	y3.Add(v.Add(&negX3).Mul(&r))          // Y3 = r*(V-X3)+Y3 (mag: 4)
+	z3.Add2(z1, &h).Square()               // Z3 = (Z1+H)^2 (mag: 1)
+	z3.Add(z1z1.Add(&hh).Negate(2))        // Z3 = Z3-(Z1Z1+HH) (mag: 4)
+
+	// Normalize the resulting field values to a magnitude of 1 as needed.
+	x3.Normalize()
+	y3.Normalize()
+	z3.Normalize()
+}
+
+// addGeneric adds two Jacobian points (x1, y1, z1) and (x2, y2, z2) without any
+// assumptions about the z values of the two points and stores the result in
+// (x3, y3, z3).  That is to say (x1, y1, z1) + (x2, y2, z2) = (x3, y3, z3).  It
+// is the slowest of the add routines due to requiring the most arithmetic.
+func (curve *KoblitzCurve) addGeneric(x1, y1, z1, x2, y2, z2, x3, y3, z3 *fieldVal) {
+	// To compute the point addition efficiently, this implementation splits
+	// the equation into intermediate elements which are used to minimize
+	// the number of field multiplications using the method shown at:
+	// http://hyperelliptic.org/EFD/g1p/auto-shortw-jacobian-0.html#addition-add-2007-bl
+	//
+	// In particular it performs the calculations using the following:
+	// Z1Z1 = Z1^2, Z2Z2 = Z2^2, U1 = X1*Z2Z2, U2 = X2*Z1Z1, S1 = Y1*Z2*Z2Z2
+	// S2 = Y2*Z1*Z1Z1, H = U2-U1, I = (2*H)^2, J = H*I, r = 2*(S2-S1)
+	// V = U1*I
+	// X3 = r^2-J-2*V, Y3 = r*(V-X3)-2*S1*J, Z3 = ((Z1+Z2)^2-Z1Z1-Z2Z2)*H
+	//
+	// This results in a cost of 11 field multiplications, 5 field squarings,
+	// 9 field additions, and 4 integer multiplications.
+
+	// When the x coordinates are the same for two points on the curve, the
+	// y coordinates either must be the same, in which case it is point
+	// doubling, or they are opposite and the result is the point at
+	// infinity.  Since any number of Jacobian coordinates can represent the
+	// same affine point, the x and y values need to be converted to like
+	// terms.
+	var z1z1, z2z2, u1, u2, s1, s2 fieldVal
+	z1z1.SquareVal(z1)                        // Z1Z1 = Z1^2 (mag: 1)
+	z2z2.SquareVal(z2)                        // Z2Z2 = Z2^2 (mag: 1)
+	u1.Set(x1).Mul(&z2z2).Normalize()         // U1 = X1*Z2Z2 (mag: 1)
+	u2.Set(x2).Mul(&z1z1).Normalize()         // U2 = X2*Z1Z1 (mag: 1)
+	s1.Set(y1).Mul(&z2z2).Mul(z2).Normalize() // S1 = Y1*Z2*Z2Z2 (mag: 1)
+	s2.Set(y2).Mul(&z1z1).Mul(z1).Normalize() // S2 = Y2*Z1*Z1Z1 (mag: 1)
+	if u1.Equals(&u2) {
+		if s1.Equals(&s2) {
+			// Since x1 == x2 and y1 == y2, point doubling must be
+			// done, otherwise the addition would end up dividing
+			// by zero.
+			curve.doubleJacobian(x1, y1, z1, x3, y3, z3)
+			return
+		}
+
+		// Since x1 == x2 and y1 == -y2, the sum is the point at
+		// infinity per the group law.
+		x3.SetInt(0)
+		y3.SetInt(0)
+		z3.SetInt(0)
+		return
+	}
+
+	// Calculate X3, Y3, and Z3 according to the intermediate elements
+	// breakdown above.
+	var h, i, j, r, rr, v fieldVal
+	var negU1, negS1, negX3 fieldVal
+	negU1.Set(&u1).Negate(1)               // negU1 = -U1 (mag: 2)
+	h.Add2(&u2, &negU1)                    // H = U2-U1 (mag: 3)
+	i.Set(&h).MulInt(2).Square()           // I = (2*H)^2 (mag: 2)
+	j.Mul2(&h, &i)                         // J = H*I (mag: 1)
+	negS1.Set(&s1).Negate(1)               // negS1 = -S1 (mag: 2)
+	r.Set(&s2).Add(&negS1).MulInt(2)       // r = 2*(S2-S1) (mag: 6)
+	rr.SquareVal(&r)                       // rr = r^2 (mag: 1)
+	v.Mul2(&u1, &i)                        // V = U1*I (mag: 1)
+	x3.Set(&v).MulInt(2).Add(&j).Negate(3) // X3 = -(J+2*V) (mag: 4)
+	x3.Add(&rr)                            // X3 = r^2+X3 (mag: 5)
+	negX3.Set(x3).Negate(5)                // negX3 = -X3 (mag: 6)
+	y3.Mul2(&s1, &j).MulInt(2).Negate(2)   // Y3 = -(2*S1*J) (mag: 3)
+	y3.Add(v.Add(&negX3).Mul(&r))          // Y3 = r*(V-X3)+Y3 (mag: 4)
+	z3.Add2(z1, z2).Square()               // Z3 = (Z1+Z2)^2 (mag: 1)
+	z3.Add(z1z1.Add(&z2z2).Negate(2))      // Z3 = Z3-(Z1Z1+Z2Z2) (mag: 4)
+	z3.Mul(&h)                             // Z3 = Z3*H (mag: 1)
+
+	// Normalize the resulting field values to a magnitude of 1 as needed.
+	x3.Normalize()
+	y3.Normalize()
+}
+
+// addJacobian adds the passed Jacobian points (x1, y1, z1) and (x2, y2, z2)
+// together and stores the result in (x3, y3, z3).
+func (curve *KoblitzCurve) addJacobian(x1, y1, z1, x2, y2, z2, x3, y3, z3 *fieldVal) {
+	// A point at infinity is the identity according to the group law for
+	// elliptic curve cryptography.  Thus, ∞ + P = P and P + ∞ = P.
+	if (x1.IsZero() && y1.IsZero()) || z1.IsZero() {
+		x3.Set(x2)
+		y3.Set(y2)
+		z3.Set(z2)
+		return
+	}
+	if (x2.IsZero() && y2.IsZero()) || z2.IsZero() {
+		x3.Set(x1)
+		y3.Set(y1)
+		z3.Set(z1)
+		return
+	}
+
+	// Faster point addition can be achieved when certain assumptions are
+	// met.  For example, when both points have the same z value, arithmetic
+	// on the z values can be avoided.  This section thus checks for these
+	// conditions and calls an appropriate add function which is accelerated
+	// by using those assumptions.
+	z1.Normalize()
+	z2.Normalize()
+	isZ1One := z1.Equals(fieldOne)
+	isZ2One := z2.Equals(fieldOne)
+	switch {
+	case isZ1One && isZ2One:
+		curve.addZ1AndZ2EqualsOne(x1, y1, z1, x2, y2, x3, y3, z3)
+		return
+	case z1.Equals(z2):
+		curve.addZ1EqualsZ2(x1, y1, z1, x2, y2, x3, y3, z3)
+		return
+	case isZ2One:
+		curve.addZ2EqualsOne(x1, y1, z1, x2, y2, x3, y3, z3)
+		return
+	}
+
+	// None of the above assumptions are true, so fall back to generic
+	// point addition.
+	curve.addGeneric(x1, y1, z1, x2, y2, z2, x3, y3, z3)
+}
+
+// Add returns the sum of (x1,y1) and (x2,y2). Part of the elliptic.Curve
+// interface.
+func (curve *KoblitzCurve) Add(x1, y1, x2, y2 *big.Int) (*big.Int, *big.Int) {
+	// A point at infinity is the identity according to the group law for
+	// elliptic curve cryptography.  Thus, ∞ + P = P and P + ∞ = P.
+	if x1.Sign() == 0 && y1.Sign() == 0 {
+		return x2, y2
+	}
+	if x2.Sign() == 0 && y2.Sign() == 0 {
+		return x1, y1
+	}
+
+	// Convert the affine coordinates from big integers to field values
+	// and do the point addition in Jacobian projective space.
+	fx1, fy1 := curve.bigAffineToField(x1, y1)
+	fx2, fy2 := curve.bigAffineToField(x2, y2)
+	fx3, fy3, fz3 := new(fieldVal), new(fieldVal), new(fieldVal)
+	fOne := new(fieldVal).SetInt(1)
+	curve.addJacobian(fx1, fy1, fOne, fx2, fy2, fOne, fx3, fy3, fz3)
+
+	// Convert the Jacobian coordinate field values back to affine big
+	// integers.
+	return curve.fieldJacobianToBigAffine(fx3, fy3, fz3)
+}
+
+// doubleZ1EqualsOne performs point doubling on the passed Jacobian point
+// when the point is already known to have a z value of 1 and stores
+// the result in (x3, y3, z3).  That is to say (x3, y3, z3) = 2*(x1, y1, 1).  It
+// performs faster point doubling than the generic routine since less arithmetic
+// is needed due to the ability to avoid multiplication by the z value.
+func (curve *KoblitzCurve) doubleZ1EqualsOne(x1, y1, x3, y3, z3 *fieldVal) {
+	// This function uses the assumptions that z1 is 1, thus the point
+	// doubling formulas reduce to:
+	//
+	// X3 = (3*X1^2)^2 - 8*X1*Y1^2
+	// Y3 = (3*X1^2)*(4*X1*Y1^2 - X3) - 8*Y1^4
+	// Z3 = 2*Y1
+	//
+	// To compute the above efficiently, this implementation splits the
+	// equation into intermediate elements which are used to minimize the
+	// number of field multiplications in favor of field squarings which
+	// are roughly 35% faster than field multiplications with the current
+	// implementation at the time this was written.
+	//
+	// This uses a slightly modified version of the method shown at:
+	// http://hyperelliptic.org/EFD/g1p/auto-shortw-jacobian-0.html#doubling-mdbl-2007-bl
+	//
+	// In particular it performs the calculations using the following:
+	// A = X1^2, B = Y1^2, C = B^2, D = 2*((X1+B)^2-A-C)
+	// E = 3*A, F = E^2, X3 = F-2*D, Y3 = E*(D-X3)-8*C
+	// Z3 = 2*Y1
+	//
+	// This results in a cost of 1 field multiplication, 5 field squarings,
+	// 6 field additions, and 5 integer multiplications.
+	var a, b, c, d, e, f fieldVal
+	z3.Set(y1).MulInt(2)                     // Z3 = 2*Y1 (mag: 2)
+	a.SquareVal(x1)                          // A = X1^2 (mag: 1)
+	b.SquareVal(y1)                          // B = Y1^2 (mag: 1)
+	c.SquareVal(&b)                          // C = B^2 (mag: 1)
+	b.Add(x1).Square()                       // B = (X1+B)^2 (mag: 1)
+	d.Set(&a).Add(&c).Negate(2)              // D = -(A+C) (mag: 3)
+	d.Add(&b).MulInt(2)                      // D = 2*(B+D)(mag: 8)
+	e.Set(&a).MulInt(3)                      // E = 3*A (mag: 3)
+	f.SquareVal(&e)                          // F = E^2 (mag: 1)
+	x3.Set(&d).MulInt(2).Negate(16)          // X3 = -(2*D) (mag: 17)
+	x3.Add(&f)                               // X3 = F+X3 (mag: 18)
+	f.Set(x3).Negate(18).Add(&d).Normalize() // F = D-X3 (mag: 1)
+	y3.Set(&c).MulInt(8).Negate(8)           // Y3 = -(8*C) (mag: 9)
+	y3.Add(f.Mul(&e))                        // Y3 = E*F+Y3 (mag: 10)
+
+	// Normalize the field values back to a magnitude of 1.
+	x3.Normalize()
+	y3.Normalize()
+	z3.Normalize()
+}
+
+// doubleGeneric performs point doubling on the passed Jacobian point without
+// any assumptions about the z value and stores the result in (x3, y3, z3).
+// That is to say (x3, y3, z3) = 2*(x1, y1, z1).  It is the slowest of the point
+// doubling routines due to requiring the most arithmetic.
+func (curve *KoblitzCurve) doubleGeneric(x1, y1, z1, x3, y3, z3 *fieldVal) {
+	// Point doubling formula for Jacobian coordinates for the secp256k1
+	// curve:
+	// X3 = (3*X1^2)^2 - 8*X1*Y1^2
+	// Y3 = (3*X1^2)*(4*X1*Y1^2 - X3) - 8*Y1^4
+	// Z3 = 2*Y1*Z1
+	//
+	// To compute the above efficiently, this implementation splits the
+	// equation into intermediate elements which are used to minimize the
+	// number of field multiplications in favor of field squarings which
+	// are roughly 35% faster than field multiplications with the current
+	// implementation at the time this was written.
+	//
+	// This uses a slightly modified version of the method shown at:
+	// http://hyperelliptic.org/EFD/g1p/auto-shortw-jacobian-0.html#doubling-dbl-2009-l
+	//
+	// In particular it performs the calculations using the following:
+	// A = X1^2, B = Y1^2, C = B^2, D = 2*((X1+B)^2-A-C)
+	// E = 3*A, F = E^2, X3 = F-2*D, Y3 = E*(D-X3)-8*C
+	// Z3 = 2*Y1*Z1
+	//
+	// This results in a cost of 1 field multiplication, 5 field squarings,
+	// 6 field additions, and 5 integer multiplications.
+	var a, b, c, d, e, f fieldVal
+	z3.Mul2(y1, z1).MulInt(2)                // Z3 = 2*Y1*Z1 (mag: 2)
+	a.SquareVal(x1)                          // A = X1^2 (mag: 1)
+	b.SquareVal(y1)                          // B = Y1^2 (mag: 1)
+	c.SquareVal(&b)                          // C = B^2 (mag: 1)
+	b.Add(x1).Square()                       // B = (X1+B)^2 (mag: 1)
+	d.Set(&a).Add(&c).Negate(2)              // D = -(A+C) (mag: 3)
+	d.Add(&b).MulInt(2)                      // D = 2*(B+D)(mag: 8)
+	e.Set(&a).MulInt(3)                      // E = 3*A (mag: 3)
+	f.SquareVal(&e)                          // F = E^2 (mag: 1)
+	x3.Set(&d).MulInt(2).Negate(16)          // X3 = -(2*D) (mag: 17)
+	x3.Add(&f)                               // X3 = F+X3 (mag: 18)
+	f.Set(x3).Negate(18).Add(&d).Normalize() // F = D-X3 (mag: 1)
+	y3.Set(&c).MulInt(8).Negate(8)           // Y3 = -(8*C) (mag: 9)
+	y3.Add(f.Mul(&e))                        // Y3 = E*F+Y3 (mag: 10)
+
+	// Normalize the field values back to a magnitude of 1.
+	x3.Normalize()
+	y3.Normalize()
+	z3.Normalize()
+}
+
+// doubleJacobian doubles the passed Jacobian point (x1, y1, z1) and stores the
+// result in (x3, y3, z3).
+func (curve *KoblitzCurve) doubleJacobian(x1, y1, z1, x3, y3, z3 *fieldVal) {
+	// Doubling a point at infinity is still infinity.
+	if y1.IsZero() || z1.IsZero() {
+		x3.SetInt(0)
+		y3.SetInt(0)
+		z3.SetInt(0)
+		return
+	}
+
+	// Slightly faster point doubling can be achieved when the z value is 1
+	// by avoiding the multiplication on the z value.  This section calls
+	// a point doubling function which is accelerated by using that
+	// assumption when possible.
+	if z1.Normalize().Equals(fieldOne) {
+		curve.doubleZ1EqualsOne(x1, y1, x3, y3, z3)
+		return
+	}
+
+	// Fall back to generic point doubling which works with arbitrary z
+	// values.
+	curve.doubleGeneric(x1, y1, z1, x3, y3, z3)
+}
+
+// Double returns 2*(x1,y1). Part of the elliptic.Curve interface.
+func (curve *KoblitzCurve) Double(x1, y1 *big.Int) (*big.Int, *big.Int) {
+	if y1.Sign() == 0 {
+		return new(big.Int), new(big.Int)
+	}
+
+	// Convert the affine coordinates from big integers to field values
+	// and do the point doubling in Jacobian projective space.
+	fx1, fy1 := curve.bigAffineToField(x1, y1)
+	fx3, fy3, fz3 := new(fieldVal), new(fieldVal), new(fieldVal)
+	fOne := new(fieldVal).SetInt(1)
+	curve.doubleJacobian(fx1, fy1, fOne, fx3, fy3, fz3)
+
+	// Convert the Jacobian coordinate field values back to affine big
+	// integers.
+	return curve.fieldJacobianToBigAffine(fx3, fy3, fz3)
+}
+
+// splitK returns a balanced length-two representation of k and their signs.
+// This is algorithm 3.74 from [GECC].
+//
+// One thing of note about this algorithm is that no matter what c1 and c2 are,
+// the final equation of k = k1 + k2 * lambda (mod n) will hold.  This is
+// provable mathematically due to how a1/b1/a2/b2 are computed.
+//
+// c1 and c2 are chosen to minimize the max(k1,k2).
+func (curve *KoblitzCurve) splitK(k []byte) ([]byte, []byte, int, int) {
+	// All math here is done with big.Int, which is slow.
+	// At some point, it might be useful to write something similar to
+	// fieldVal but for N instead of P as the prime field if this ends up
+	// being a bottleneck.
+	bigIntK := new(big.Int)
+	c1, c2 := new(big.Int), new(big.Int)
+	tmp1, tmp2 := new(big.Int), new(big.Int)
+	k1, k2 := new(big.Int), new(big.Int)
+
+	bigIntK.SetBytes(k)
+	// c1 = round(b2 * k / n) from step 4.
+	// Rounding isn't really necessary and costs too much, hence skipped
+	c1.Mul(curve.b2, bigIntK)
+	c1.Div(c1, curve.N)
+	// c2 = round(b1 * k / n) from step 4 (sign reversed to optimize one step)
+	// Rounding isn't really necessary and costs too much, hence skipped
+	c2.Mul(curve.b1, bigIntK)
+	c2.Div(c2, curve.N)
+	// k1 = k - c1 * a1 - c2 * a2 from step 5 (note c2's sign is reversed)
+	tmp1.Mul(c1, curve.a1)
+	tmp2.Mul(c2, curve.a2)
+	k1.Sub(bigIntK, tmp1)
+	k1.Add(k1, tmp2)
+	// k2 = - c1 * b1 - c2 * b2 from step 5 (note c2's sign is reversed)
+	tmp1.Mul(c1, curve.b1)
+	tmp2.Mul(c2, curve.b2)
+	k2.Sub(tmp2, tmp1)
+
+	// Note Bytes() throws out the sign of k1 and k2. This matters
+	// since k1 and/or k2 can be negative. Hence, we pass that
+	// back separately.
+	return k1.Bytes(), k2.Bytes(), k1.Sign(), k2.Sign()
+}
+
+// moduloReduce reduces k from more than 32 bytes to 32 bytes and under.  This
+// is done by doing a simple modulo curve.N.  We can do this since G^N = 1 and
+// thus any other valid point on the elliptic curve has the same order.
+func (curve *KoblitzCurve) moduloReduce(k []byte) []byte {
+	// Since the order of G is curve.N, we can use a much smaller number
+	// by doing modulo curve.N
+	if len(k) > curve.byteSize {
+		// Reduce k by performing modulo curve.N.
+		tmpK := new(big.Int).SetBytes(k)
+		tmpK.Mod(tmpK, curve.N)
+		return tmpK.Bytes()
+	}
+
+	return k
+}
+
+// NAF takes a positive integer k and returns the Non-Adjacent Form (NAF) as two
+// byte slices.  The first is where 1s will be.  The second is where -1s will
+// be.  NAF is convenient in that on average, only 1/3rd of its values are
+// non-zero.  This is algorithm 3.30 from [GECC].
+//
+// Essentially, this makes it possible to minimize the number of operations
+// since the resulting ints returned will be at least 50% 0s.
+func NAF(k []byte) ([]byte, []byte) {
+	// The essence of this algorithm is that whenever we have consecutive 1s
+	// in the binary, we want to put a -1 in the lowest bit and get a bunch
+	// of 0s up to the highest bit of consecutive 1s.  This is due to this
+	// identity:
+	// 2^n + 2^(n-1) + 2^(n-2) + ... + 2^(n-k) = 2^(n+1) - 2^(n-k)
+	//
+	// The algorithm thus may need to go 1 more bit than the length of the
+	// bits we actually have, hence bits being 1 bit longer than was
+	// necessary.  Since we need to know whether adding will cause a carry,
+	// we go from right-to-left in this addition.
+	var carry, curIsOne, nextIsOne bool
+	// these default to zero
+	retPos := make([]byte, len(k)+1)
+	retNeg := make([]byte, len(k)+1)
+	for i := len(k) - 1; i >= 0; i-- {
+		curByte := k[i]
+		for j := uint(0); j < 8; j++ {
+			curIsOne = curByte&1 == 1
+			if j == 7 {
+				if i == 0 {
+					nextIsOne = false
+				} else {
+					nextIsOne = k[i-1]&1 == 1
+				}
+			} else {
+				nextIsOne = curByte&2 == 2
+			}
+			if carry {
+				if curIsOne {
+					// This bit is 1, so continue to carry
+					// and don't need to do anything.
+				} else {
+					// We've hit a 0 after some number of
+					// 1s.
+					if nextIsOne {
+						// Start carrying again since
+						// a new sequence of 1s is
+						// starting.
+						retNeg[i+1] += 1 << j
+					} else {
+						// Stop carrying since 1s have
+						// stopped.
+						carry = false
+						retPos[i+1] += 1 << j
+					}
+				}
+			} else if curIsOne {
+				if nextIsOne {
+					// If this is the start of at least 2
+					// consecutive 1s, set the current one
+					// to -1 and start carrying.
+					retNeg[i+1] += 1 << j
+					carry = true
+				} else {
+					// This is a singleton, not consecutive
+					// 1s.
+					retPos[i+1] += 1 << j
+				}
+			}
+			curByte >>= 1
+		}
+	}
+	if carry {
+		retPos[0] = 1
+		return retPos, retNeg
+	}
+	return retPos[1:], retNeg[1:]
+}
+
+// ScalarMult returns k*(Bx, By) where k is a big endian integer.
+// Part of the elliptic.Curve interface.
+func (curve *KoblitzCurve) ScalarMult(Bx, By *big.Int, k []byte) (*big.Int, *big.Int) {
+	// Point Q = ∞ (point at infinity).
+	qx, qy, qz := new(fieldVal), new(fieldVal), new(fieldVal)
+
+	// Decompose K into k1 and k2 in order to halve the number of EC ops.
+	// See Algorithm 3.74 in [GECC].
+	k1, k2, signK1, signK2 := curve.splitK(curve.moduloReduce(k))
+
+	// The main equation here to remember is:
+	//   k * P = k1 * P + k2 * ϕ(P)
+	//
+	// P1 below is P in the equation, P2 below is ϕ(P) in the equation
+	p1x, p1y := curve.bigAffineToField(Bx, By)
+	p1yNeg := new(fieldVal).NegateVal(p1y, 1)
+	p1z := new(fieldVal).SetInt(1)
+
+	// NOTE: ϕ(x,y) = (βx,y).  The Jacobian z coordinate is 1, so this math
+	// goes through.
+	p2x := new(fieldVal).Mul2(p1x, curve.beta)
+	p2y := new(fieldVal).Set(p1y)
+	p2yNeg := new(fieldVal).NegateVal(p2y, 1)
+	p2z := new(fieldVal).SetInt(1)
+
+	// Flip the positive and negative values of the points as needed
+	// depending on the signs of k1 and k2.  As mentioned in the equation
+	// above, each of k1 and k2 are multiplied by the respective point.
+	// Since -k * P is the same thing as k * -P, and the group law for
+	// elliptic curves states that P(x, y) = -P(x, -y), it's faster and
+	// simplifies the code to just make the point negative.
+	if signK1 == -1 {
+		p1y, p1yNeg = p1yNeg, p1y
+	}
+	if signK2 == -1 {
+		p2y, p2yNeg = p2yNeg, p2y
+	}
+
+	// NAF versions of k1 and k2 should have a lot more zeros.
+	//
+	// The Pos version of the bytes contain the +1s and the Neg versions
+	// contain the -1s.
+	k1PosNAF, k1NegNAF := NAF(k1)
+	k2PosNAF, k2NegNAF := NAF(k2)
+	k1Len := len(k1PosNAF)
+	k2Len := len(k2PosNAF)
+
+	m := k1Len
+	if m < k2Len {
+		m = k2Len
+	}
+
+	// Add left-to-right using the NAF optimization.  See algorithm 3.77
+	// from [GECC].  This should be faster overall since there will be a lot
+	// more instances of 0, hence reducing the number of Jacobian additions
+	// at the cost of 1 possible extra doubling.
+	var k1BytePos, k1ByteNeg, k2BytePos, k2ByteNeg byte
+	for i := 0; i < m; i++ {
+		// Since we're going left-to-right, pad the front with 0s.
+		if i < m-k1Len {
+			k1BytePos = 0
+			k1ByteNeg = 0
+		} else {
+			k1BytePos = k1PosNAF[i-(m-k1Len)]
+			k1ByteNeg = k1NegNAF[i-(m-k1Len)]
+		}
+		if i < m-k2Len {
+			k2BytePos = 0
+			k2ByteNeg = 0
+		} else {
+			k2BytePos = k2PosNAF[i-(m-k2Len)]
+			k2ByteNeg = k2NegNAF[i-(m-k2Len)]
+		}
+
+		for j := 7; j >= 0; j-- {
+			// Q = 2 * Q
+			curve.doubleJacobian(qx, qy, qz, qx, qy, qz)
+
+			if k1BytePos&0x80 == 0x80 {
+				curve.addJacobian(qx, qy, qz, p1x, p1y, p1z,
+					qx, qy, qz)
+			} else if k1ByteNeg&0x80 == 0x80 {
+				curve.addJacobian(qx, qy, qz, p1x, p1yNeg, p1z,
+					qx, qy, qz)
+			}
+
+			if k2BytePos&0x80 == 0x80 {
+				curve.addJacobian(qx, qy, qz, p2x, p2y, p2z,
+					qx, qy, qz)
+			} else if k2ByteNeg&0x80 == 0x80 {
+				curve.addJacobian(qx, qy, qz, p2x, p2yNeg, p2z,
+					qx, qy, qz)
+			}
+			k1BytePos <<= 1
+			k1ByteNeg <<= 1
+			k2BytePos <<= 1
+			k2ByteNeg <<= 1
+		}
+	}
+
+	// Convert the Jacobian coordinate field values back to affine big.Ints.
+	return curve.fieldJacobianToBigAffine(qx, qy, qz)
+}
+
+// ScalarBaseMult returns k*G where G is the base point of the group and k is a
+// big endian integer.
+// Part of the elliptic.Curve interface.
+func (curve *KoblitzCurve) ScalarBaseMult(k []byte) (*big.Int, *big.Int) {
+	newK := curve.moduloReduce(k)
+	diff := len(curve.bytePoints) - len(newK)
+
+	// Point Q = ∞ (point at infinity).
+	qx, qy, qz := new(fieldVal), new(fieldVal), new(fieldVal)
+
+	// curve.bytePoints has all 256 byte points for each 8-bit window. The
+	// strategy is to add up the byte points. This is best understood by
+	// expressing k in base-256 which it already sort of is.
+	// Each "digit" in the 8-bit window can be looked up using bytePoints
+	// and added together.
+	for i, byteVal := range newK {
+		p := curve.bytePoints[diff+i][byteVal]
+		curve.addJacobian(qx, qy, qz, &p[0], &p[1], &p[2], qx, qy, qz)
+	}
+	return curve.fieldJacobianToBigAffine(qx, qy, qz)
+}
+
+// QPlus1Div4 returns the (P+1)/4 constant for the curve for use in calculating
+// square roots via exponentiation.
+//
+// DEPRECATED: The actual value returned is (P+1)/4, where as the original
+// method name implies that this value is (((P+1)/4)+1)/4. This method is kept
+// to maintain backwards compatibility of the API. Use Q() instead.
+func (curve *KoblitzCurve) QPlus1Div4() *big.Int {
+	return curve.q
+}
+
+// Q returns the (P+1)/4 constant for the curve for use in calculating square
+// roots via exponentiation.
+func (curve *KoblitzCurve) Q() *big.Int {
+	return curve.q
+}
+
+var initonce sync.Once
+var secp256k1 KoblitzCurve
+
+func initAll() {
+	initS256()
+}
+
+// fromHex converts the passed hex string into a big integer pointer and will
+// panic is there is an error.  This is only provided for the hard-coded
+// constants so errors in the source code can bet detected. It will only (and
+// must only) be called for initialization purposes.
+func fromHex(s string) *big.Int {
+	r, ok := new(big.Int).SetString(s, 16)
+	if !ok {
+		panic("invalid hex in source file: " + s)
+	}
+	return r
+}
+
+func initS256() {
+	// Curve parameters taken from [SECG] section 2.4.1.
+	secp256k1.CurveParams = new(elliptic.CurveParams)
+	secp256k1.P = fromHex("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F")
+	secp256k1.N = fromHex("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141")
+	secp256k1.B = fromHex("0000000000000000000000000000000000000000000000000000000000000007")
+	secp256k1.Gx = fromHex("79BE667EF9DCBBAC55A06295CE870B07029BFCDB2DCE28D959F2815B16F81798")
+	secp256k1.Gy = fromHex("483ADA7726A3C4655DA4FBFC0E1108A8FD17B448A68554199C47D08FFB10D4B8")
+	secp256k1.BitSize = 256
+	secp256k1.q = new(big.Int).Div(new(big.Int).Add(secp256k1.P,
+		big.NewInt(1)), big.NewInt(4))
+	secp256k1.H = 1
+	secp256k1.halfOrder = new(big.Int).Rsh(secp256k1.N, 1)
+	secp256k1.fieldB = new(fieldVal).SetByteSlice(secp256k1.B.Bytes())
+
+	// Provided for convenience since this gets computed repeatedly.
+	secp256k1.byteSize = secp256k1.BitSize / 8
+
+	// Deserialize and set the pre-computed table used to accelerate scalar
+	// base multiplication.  This is hard-coded data, so any errors are
+	// panics because it means something is wrong in the source code.
+	if err := loadS256BytePoints(); err != nil {
+		panic(err)
+	}
+
+	// Next 6 constants are from Hal Finney's bitcointalk.org post:
+	// https://bitcointalk.org/index.php?topic=3238.msg45565#msg45565
+	// May he rest in peace.
+	//
+	// They have also been independently derived from the code in the
+	// EndomorphismVectors function in gensecp256k1.go.
+	secp256k1.lambda = fromHex("5363AD4CC05C30E0A5261C028812645A122E22EA20816678DF02967C1B23BD72")
+	secp256k1.beta = new(fieldVal).SetHex("7AE96A2B657C07106E64479EAC3434E99CF0497512F58995C1396C28719501EE")
+	secp256k1.a1 = fromHex("3086D221A7D46BCDE86C90E49284EB15")
+	secp256k1.b1 = fromHex("-E4437ED6010E88286F547FA90ABFE4C3")
+	secp256k1.a2 = fromHex("114CA50F7A8E2F3F657C1108D9D44CFD8")
+	secp256k1.b2 = fromHex("3086D221A7D46BCDE86C90E49284EB15")
+
+	// Alternatively, we can use the parameters below, however, they seem
+	//  to be about 8% slower.
+	// secp256k1.lambda = fromHex("AC9C52B33FA3CF1F5AD9E3FD77ED9BA4A880B9FC8EC739C2E0CFC810B51283CE")
+	// secp256k1.beta = new(fieldVal).SetHex("851695D49A83F8EF919BB86153CBCB16630FB68AED0A766A3EC693D68E6AFA40")
+	// secp256k1.a1 = fromHex("E4437ED6010E88286F547FA90ABFE4C3")
+	// secp256k1.b1 = fromHex("-3086D221A7D46BCDE86C90E49284EB15")
+	// secp256k1.a2 = fromHex("3086D221A7D46BCDE86C90E49284EB15")
+	// secp256k1.b2 = fromHex("114CA50F7A8E2F3F657C1108D9D44CFD8")
+}
+
+// S256 returns a Curve which implements secp256k1.
+func S256() *KoblitzCurve {
+	initonce.Do(initAll)
+	return &secp256k1
+}

vendor/github.com/btcsuite/btcd/btcec/ciphering.go

@@ -0,0 +1,216 @@
+// Copyright (c) 2015-2016 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package btcec
+
+import (
+	"bytes"
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/hmac"
+	"crypto/rand"
+	"crypto/sha256"
+	"crypto/sha512"
+	"errors"
+	"io"
+)
+
+var (
+	// ErrInvalidMAC occurs when Message Authentication Check (MAC) fails
+	// during decryption. This happens because of either invalid private key or
+	// corrupt ciphertext.
+	ErrInvalidMAC = errors.New("invalid mac hash")
+
+	// errInputTooShort occurs when the input ciphertext to the Decrypt
+	// function is less than 134 bytes long.
+	errInputTooShort = errors.New("ciphertext too short")
+
+	// errUnsupportedCurve occurs when the first two bytes of the encrypted
+	// text aren't 0x02CA (= 712 = secp256k1, from OpenSSL).
+	errUnsupportedCurve = errors.New("unsupported curve")
+
+	errInvalidXLength = errors.New("invalid X length, must be 32")
+	errInvalidYLength = errors.New("invalid Y length, must be 32")
+	errInvalidPadding = errors.New("invalid PKCS#7 padding")
+
+	// 0x02CA = 714
+	ciphCurveBytes = [2]byte{0x02, 0xCA}
+	// 0x20 = 32
+	ciphCoordLength = [2]byte{0x00, 0x20}
+)
+
+// GenerateSharedSecret generates a shared secret based on a private key and a
+// public key using Diffie-Hellman key exchange (ECDH) (RFC 4753).
+// RFC5903 Section 9 states we should only return x.
+func GenerateSharedSecret(privkey *PrivateKey, pubkey *PublicKey) []byte {
+	x, _ := pubkey.Curve.ScalarMult(pubkey.X, pubkey.Y, privkey.D.Bytes())
+	return x.Bytes()
+}
+
+// Encrypt encrypts data for the target public key using AES-256-CBC. It also
+// generates a private key (the pubkey of which is also in the output). The only
+// supported curve is secp256k1. The `structure' that it encodes everything into
+// is:
+//
+//	struct {
+//		// Initialization Vector used for AES-256-CBC
+//		IV [16]byte
+//		// Public Key: curve(2) + len_of_pubkeyX(2) + pubkeyX +
+//		// len_of_pubkeyY(2) + pubkeyY (curve = 714)
+//		PublicKey [70]byte
+//		// Cipher text
+//		Data []byte
+//		// HMAC-SHA-256 Message Authentication Code
+//		HMAC [32]byte
+//	}
+//
+// The primary aim is to ensure byte compatibility with Pyelliptic.  Also, refer
+// to section 5.8.1 of ANSI X9.63 for rationale on this format.
+func Encrypt(pubkey *PublicKey, in []byte) ([]byte, error) {
+	ephemeral, err := NewPrivateKey(S256())
+	if err != nil {
+		return nil, err
+	}
+	ecdhKey := GenerateSharedSecret(ephemeral, pubkey)
+	derivedKey := sha512.Sum512(ecdhKey)
+	keyE := derivedKey[:32]
+	keyM := derivedKey[32:]
+
+	paddedIn := addPKCSPadding(in)
+	// IV + Curve params/X/Y + padded plaintext/ciphertext + HMAC-256
+	out := make([]byte, aes.BlockSize+70+len(paddedIn)+sha256.Size)
+	iv := out[:aes.BlockSize]
+	if _, err = io.ReadFull(rand.Reader, iv); err != nil {
+		return nil, err
+	}
+	// start writing public key
+	pb := ephemeral.PubKey().SerializeUncompressed()
+	offset := aes.BlockSize
+
+	// curve and X length
+	copy(out[offset:offset+4], append(ciphCurveBytes[:], ciphCoordLength[:]...))
+	offset += 4
+	// X
+	copy(out[offset:offset+32], pb[1:33])
+	offset += 32
+	// Y length
+	copy(out[offset:offset+2], ciphCoordLength[:])
+	offset += 2
+	// Y
+	copy(out[offset:offset+32], pb[33:])
+	offset += 32
+
+	// start encryption
+	block, err := aes.NewCipher(keyE)
+	if err != nil {
+		return nil, err
+	}
+	mode := cipher.NewCBCEncrypter(block, iv)
+	mode.CryptBlocks(out[offset:len(out)-sha256.Size], paddedIn)
+
+	// start HMAC-SHA-256
+	hm := hmac.New(sha256.New, keyM)
+	hm.Write(out[:len(out)-sha256.Size])          // everything is hashed
+	copy(out[len(out)-sha256.Size:], hm.Sum(nil)) // write checksum
+
+	return out, nil
+}
+
+// Decrypt decrypts data that was encrypted using the Encrypt function.
+func Decrypt(priv *PrivateKey, in []byte) ([]byte, error) {
+	// IV + Curve params/X/Y + 1 block + HMAC-256
+	if len(in) < aes.BlockSize+70+aes.BlockSize+sha256.Size {
+		return nil, errInputTooShort
+	}
+
+	// read iv
+	iv := in[:aes.BlockSize]
+	offset := aes.BlockSize
+
+	// start reading pubkey
+	if !bytes.Equal(in[offset:offset+2], ciphCurveBytes[:]) {
+		return nil, errUnsupportedCurve
+	}
+	offset += 2
+
+	if !bytes.Equal(in[offset:offset+2], ciphCoordLength[:]) {
+		return nil, errInvalidXLength
+	}
+	offset += 2
+
+	xBytes := in[offset : offset+32]
+	offset += 32
+
+	if !bytes.Equal(in[offset:offset+2], ciphCoordLength[:]) {
+		return nil, errInvalidYLength
+	}
+	offset += 2
+
+	yBytes := in[offset : offset+32]
+	offset += 32
+
+	pb := make([]byte, 65)
+	pb[0] = byte(0x04) // uncompressed
+	copy(pb[1:33], xBytes)
+	copy(pb[33:], yBytes)
+	// check if (X, Y) lies on the curve and create a Pubkey if it does
+	pubkey, err := ParsePubKey(pb, S256())
+	if err != nil {
+		return nil, err
+	}
+
+	// check for cipher text length
+	if (len(in)-aes.BlockSize-offset-sha256.Size)%aes.BlockSize != 0 {
+		return nil, errInvalidPadding // not padded to 16 bytes
+	}
+
+	// read hmac
+	messageMAC := in[len(in)-sha256.Size:]
+
+	// generate shared secret
+	ecdhKey := GenerateSharedSecret(priv, pubkey)
+	derivedKey := sha512.Sum512(ecdhKey)
+	keyE := derivedKey[:32]
+	keyM := derivedKey[32:]
+
+	// verify mac
+	hm := hmac.New(sha256.New, keyM)
+	hm.Write(in[:len(in)-sha256.Size]) // everything is hashed
+	expectedMAC := hm.Sum(nil)
+	if !hmac.Equal(messageMAC, expectedMAC) {
+		return nil, ErrInvalidMAC
+	}
+
+	// start decryption
+	block, err := aes.NewCipher(keyE)
+	if err != nil {
+		return nil, err
+	}
+	mode := cipher.NewCBCDecrypter(block, iv)
+	// same length as ciphertext
+	plaintext := make([]byte, len(in)-offset-sha256.Size)
+	mode.CryptBlocks(plaintext, in[offset:len(in)-sha256.Size])
+
+	return removePKCSPadding(plaintext)
+}
+
+// Implement PKCS#7 padding with block size of 16 (AES block size).
+
+// addPKCSPadding adds padding to a block of data
+func addPKCSPadding(src []byte) []byte {
+	padding := aes.BlockSize - len(src)%aes.BlockSize
+	padtext := bytes.Repeat([]byte{byte(padding)}, padding)
+	return append(src, padtext...)
+}
+
+// removePKCSPadding removes padding from data that was added with addPKCSPadding
+func removePKCSPadding(src []byte) ([]byte, error) {
+	length := len(src)
+	padLength := int(src[length-1])
+	if padLength > aes.BlockSize || length < aes.BlockSize {
+		return nil, errInvalidPadding
+	}
+
+	return src[:length-padLength], nil
+}

vendor/github.com/btcsuite/btcd/btcec/doc.go

@@ -0,0 +1,21 @@
+// Copyright (c) 2013-2014 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+/*
+Package btcec implements support for the elliptic curves needed for bitcoin.
+
+Bitcoin uses elliptic curve cryptography using koblitz curves
+(specifically secp256k1) for cryptographic functions.  See
+http://www.secg.org/collateral/sec2_final.pdf for details on the
+standard.
+
+This package provides the data structures and functions implementing the
+crypto/elliptic Curve interface in order to permit using these curves
+with the standard crypto/ecdsa package provided with go. Helper
+functionality is provided to parse signatures and public keys from
+standard formats.  It was designed for use with btcd, but should be
+general enough for other uses of elliptic curve crypto.  It was originally based
+on some initial work by ThePiachu, but has significantly diverged since then.
+*/
+package btcec

vendor/github.com/btcsuite/btcd/btcec/gensecp256k1.go

@@ -0,0 +1,203 @@
+// Copyright (c) 2014-2015 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+// This file is ignored during the regular build due to the following build tag.
+// This build tag is set during go generate.
+// +build gensecp256k1
+
+package btcec
+
+// References:
+//   [GECC]: Guide to Elliptic Curve Cryptography (Hankerson, Menezes, Vanstone)
+
+import (
+	"encoding/binary"
+	"math/big"
+)
+
+// secp256k1BytePoints are dummy points used so the code which generates the
+// real values can compile.
+var secp256k1BytePoints = ""
+
+// getDoublingPoints returns all the possible G^(2^i) for i in
+// 0..n-1 where n is the curve's bit size (256 in the case of secp256k1)
+// the coordinates are recorded as Jacobian coordinates.
+func (curve *KoblitzCurve) getDoublingPoints() [][3]fieldVal {
+	doublingPoints := make([][3]fieldVal, curve.BitSize)
+
+	// initialize px, py, pz to the Jacobian coordinates for the base point
+	px, py := curve.bigAffineToField(curve.Gx, curve.Gy)
+	pz := new(fieldVal).SetInt(1)
+	for i := 0; i < curve.BitSize; i++ {
+		doublingPoints[i] = [3]fieldVal{*px, *py, *pz}
+		// P = 2*P
+		curve.doubleJacobian(px, py, pz, px, py, pz)
+	}
+	return doublingPoints
+}
+
+// SerializedBytePoints returns a serialized byte slice which contains all of
+// the possible points per 8-bit window.  This is used to when generating
+// secp256k1.go.
+func (curve *KoblitzCurve) SerializedBytePoints() []byte {
+	doublingPoints := curve.getDoublingPoints()
+
+	// Segregate the bits into byte-sized windows
+	serialized := make([]byte, curve.byteSize*256*3*10*4)
+	offset := 0
+	for byteNum := 0; byteNum < curve.byteSize; byteNum++ {
+		// Grab the 8 bits that make up this byte from doublingPoints.
+		startingBit := 8 * (curve.byteSize - byteNum - 1)
+		computingPoints := doublingPoints[startingBit : startingBit+8]
+
+		// Compute all points in this window and serialize them.
+		for i := 0; i < 256; i++ {
+			px, py, pz := new(fieldVal), new(fieldVal), new(fieldVal)
+			for j := 0; j < 8; j++ {
+				if i>>uint(j)&1 == 1 {
+					curve.addJacobian(px, py, pz, &computingPoints[j][0],
+						&computingPoints[j][1], &computingPoints[j][2], px, py, pz)
+				}
+			}
+			for i := 0; i < 10; i++ {
+				binary.LittleEndian.PutUint32(serialized[offset:], px.n[i])
+				offset += 4
+			}
+			for i := 0; i < 10; i++ {
+				binary.LittleEndian.PutUint32(serialized[offset:], py.n[i])
+				offset += 4
+			}
+			for i := 0; i < 10; i++ {
+				binary.LittleEndian.PutUint32(serialized[offset:], pz.n[i])
+				offset += 4
+			}
+		}
+	}
+
+	return serialized
+}
+
+// sqrt returns the square root of the provided big integer using Newton's
+// method.  It's only compiled and used during generation of pre-computed
+// values, so speed is not a huge concern.
+func sqrt(n *big.Int) *big.Int {
+	// Initial guess = 2^(log_2(n)/2)
+	guess := big.NewInt(2)
+	guess.Exp(guess, big.NewInt(int64(n.BitLen()/2)), nil)
+
+	// Now refine using Newton's method.
+	big2 := big.NewInt(2)
+	prevGuess := big.NewInt(0)
+	for {
+		prevGuess.Set(guess)
+		guess.Add(guess, new(big.Int).Div(n, guess))
+		guess.Div(guess, big2)
+		if guess.Cmp(prevGuess) == 0 {
+			break
+		}
+	}
+	return guess
+}
+
+// EndomorphismVectors runs the first 3 steps of algorithm 3.74 from [GECC] to
+// generate the linearly independent vectors needed to generate a balanced
+// length-two representation of a multiplier such that k = k1 + k2λ (mod N) and
+// returns them.  Since the values will always be the same given the fact that N
+// and λ are fixed, the final results can be accelerated by storing the
+// precomputed values with the curve.
+func (curve *KoblitzCurve) EndomorphismVectors() (a1, b1, a2, b2 *big.Int) {
+	bigMinus1 := big.NewInt(-1)
+
+	// This section uses an extended Euclidean algorithm to generate a
+	// sequence of equations:
+	//  s[i] * N + t[i] * λ = r[i]
+
+	nSqrt := sqrt(curve.N)
+	u, v := new(big.Int).Set(curve.N), new(big.Int).Set(curve.lambda)
+	x1, y1 := big.NewInt(1), big.NewInt(0)
+	x2, y2 := big.NewInt(0), big.NewInt(1)
+	q, r := new(big.Int), new(big.Int)
+	qu, qx1, qy1 := new(big.Int), new(big.Int), new(big.Int)
+	s, t := new(big.Int), new(big.Int)
+	ri, ti := new(big.Int), new(big.Int)
+	a1, b1, a2, b2 = new(big.Int), new(big.Int), new(big.Int), new(big.Int)
+	found, oneMore := false, false
+	for u.Sign() != 0 {
+		// q = v/u
+		q.Div(v, u)
+
+		// r = v - q*u
+		qu.Mul(q, u)
+		r.Sub(v, qu)
+
+		// s = x2 - q*x1
+		qx1.Mul(q, x1)
+		s.Sub(x2, qx1)
+
+		// t = y2 - q*y1
+		qy1.Mul(q, y1)
+		t.Sub(y2, qy1)
+
+		// v = u, u = r, x2 = x1, x1 = s, y2 = y1, y1 = t
+		v.Set(u)
+		u.Set(r)
+		x2.Set(x1)
+		x1.Set(s)
+		y2.Set(y1)
+		y1.Set(t)
+
+		// As soon as the remainder is less than the sqrt of n, the
+		// values of a1 and b1 are known.
+		if !found && r.Cmp(nSqrt) < 0 {
+			// When this condition executes ri and ti represent the
+			// r[i] and t[i] values such that i is the greatest
+			// index for which r >= sqrt(n).  Meanwhile, the current
+			// r and t values are r[i+1] and t[i+1], respectively.
+
+			// a1 = r[i+1], b1 = -t[i+1]
+			a1.Set(r)
+			b1.Mul(t, bigMinus1)
+			found = true
+			oneMore = true
+
+			// Skip to the next iteration so ri and ti are not
+			// modified.
+			continue
+
+		} else if oneMore {
+			// When this condition executes ri and ti still
+			// represent the r[i] and t[i] values while the current
+			// r and t are r[i+2] and t[i+2], respectively.
+
+			// sum1 = r[i]^2 + t[i]^2
+			rSquared := new(big.Int).Mul(ri, ri)
+			tSquared := new(big.Int).Mul(ti, ti)
+			sum1 := new(big.Int).Add(rSquared, tSquared)
+
+			// sum2 = r[i+2]^2 + t[i+2]^2
+			r2Squared := new(big.Int).Mul(r, r)
+			t2Squared := new(big.Int).Mul(t, t)
+			sum2 := new(big.Int).Add(r2Squared, t2Squared)
+
+			// if (r[i]^2 + t[i]^2) <= (r[i+2]^2 + t[i+2]^2)
+			if sum1.Cmp(sum2) <= 0 {
+				// a2 = r[i], b2 = -t[i]
+				a2.Set(ri)
+				b2.Mul(ti, bigMinus1)
+			} else {
+				// a2 = r[i+2], b2 = -t[i+2]
+				a2.Set(r)
+				b2.Mul(t, bigMinus1)
+			}
+
+			// All done.
+			break
+		}
+
+		ri.Set(r)
+		ti.Set(t)
+	}
+
+	return a1, b1, a2, b2
+}

vendor/github.com/btcsuite/btcd/btcec/precompute.go

@@ -0,0 +1,67 @@
+// Copyright 2015 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package btcec
+
+import (
+	"compress/zlib"
+	"encoding/base64"
+	"encoding/binary"
+	"io/ioutil"
+	"strings"
+)
+
+//go:generate go run -tags gensecp256k1 genprecomps.go
+
+// loadS256BytePoints decompresses and deserializes the pre-computed byte points
+// used to accelerate scalar base multiplication for the secp256k1 curve.  This
+// approach is used since it allows the compile to use significantly less ram
+// and be performed much faster than it is with hard-coding the final in-memory
+// data structure.  At the same time, it is quite fast to generate the in-memory
+// data structure at init time with this approach versus computing the table.
+func loadS256BytePoints() error {
+	// There will be no byte points to load when generating them.
+	bp := secp256k1BytePoints
+	if len(bp) == 0 {
+		return nil
+	}
+
+	// Decompress the pre-computed table used to accelerate scalar base
+	// multiplication.
+	decoder := base64.NewDecoder(base64.StdEncoding, strings.NewReader(bp))
+	r, err := zlib.NewReader(decoder)
+	if err != nil {
+		return err
+	}
+	serialized, err := ioutil.ReadAll(r)
+	if err != nil {
+		return err
+	}
+
+	// Deserialize the precomputed byte points and set the curve to them.
+	offset := 0
+	var bytePoints [32][256][3]fieldVal
+	for byteNum := 0; byteNum < 32; byteNum++ {
+		// All points in this window.
+		for i := 0; i < 256; i++ {
+			px := &bytePoints[byteNum][i][0]
+			py := &bytePoints[byteNum][i][1]
+			pz := &bytePoints[byteNum][i][2]
+			for i := 0; i < 10; i++ {
+				px.n[i] = binary.LittleEndian.Uint32(serialized[offset:])
+				offset += 4
+			}
+			for i := 0; i < 10; i++ {
+				py.n[i] = binary.LittleEndian.Uint32(serialized[offset:])
+				offset += 4
+			}
+			for i := 0; i < 10; i++ {
+				pz.n[i] = binary.LittleEndian.Uint32(serialized[offset:])
+				offset += 4
+			}
+		}
+	}
+	secp256k1.bytePoints = &bytePoints
+	return nil
+}

vendor/github.com/btcsuite/btcd/btcec/privkey.go

@@ -0,0 +1,73 @@
+// Copyright (c) 2013-2016 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package btcec
+
+import (
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/rand"
+	"math/big"
+)
+
+// PrivateKey wraps an ecdsa.PrivateKey as a convenience mainly for signing
+// things with the the private key without having to directly import the ecdsa
+// package.
+type PrivateKey ecdsa.PrivateKey
+
+// PrivKeyFromBytes returns a private and public key for `curve' based on the
+// private key passed as an argument as a byte slice.
+func PrivKeyFromBytes(curve elliptic.Curve, pk []byte) (*PrivateKey,
+	*PublicKey) {
+	x, y := curve.ScalarBaseMult(pk)
+
+	priv := &ecdsa.PrivateKey{
+		PublicKey: ecdsa.PublicKey{
+			Curve: curve,
+			X:     x,
+			Y:     y,
+		},
+		D: new(big.Int).SetBytes(pk),
+	}
+
+	return (*PrivateKey)(priv), (*PublicKey)(&priv.PublicKey)
+}
+
+// NewPrivateKey is a wrapper for ecdsa.GenerateKey that returns a PrivateKey
+// instead of the normal ecdsa.PrivateKey.
+func NewPrivateKey(curve elliptic.Curve) (*PrivateKey, error) {
+	key, err := ecdsa.GenerateKey(curve, rand.Reader)
+	if err != nil {
+		return nil, err
+	}
+	return (*PrivateKey)(key), nil
+}
+
+// PubKey returns the PublicKey corresponding to this private key.
+func (p *PrivateKey) PubKey() *PublicKey {
+	return (*PublicKey)(&p.PublicKey)
+}
+
+// ToECDSA returns the private key as a *ecdsa.PrivateKey.
+func (p *PrivateKey) ToECDSA() *ecdsa.PrivateKey {
+	return (*ecdsa.PrivateKey)(p)
+}
+
+// Sign generates an ECDSA signature for the provided hash (which should be the result
+// of hashing a larger message) using the private key. Produced signature
+// is deterministic (same message and same key yield the same signature) and canonical
+// in accordance with RFC6979 and BIP0062.
+func (p *PrivateKey) Sign(hash []byte) (*Signature, error) {
+	return signRFC6979(p, hash)
+}
+
+// PrivKeyBytesLen defines the length in bytes of a serialized private key.
+const PrivKeyBytesLen = 32
+
+// Serialize returns the private key number d as a big-endian binary-encoded
+// number, padded to a length of 32 bytes.
+func (p *PrivateKey) Serialize() []byte {
+	b := make([]byte, 0, PrivKeyBytesLen)
+	return paddedAppend(PrivKeyBytesLen, b, p.ToECDSA().D.Bytes())
+}

vendor/github.com/btcsuite/btcd/btcec/pubkey.go

@@ -0,0 +1,194 @@
+// Copyright (c) 2013-2014 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package btcec
+
+import (
+	"crypto/ecdsa"
+	"errors"
+	"fmt"
+	"math/big"
+)
+
+// These constants define the lengths of serialized public keys.
+const (
+	PubKeyBytesLenCompressed   = 33
+	PubKeyBytesLenUncompressed = 65
+	PubKeyBytesLenHybrid       = 65
+)
+
+func isOdd(a *big.Int) bool {
+	return a.Bit(0) == 1
+}
+
+// decompressPoint decompresses a point on the secp256k1 curve given the X point and
+// the solution to use.
+func decompressPoint(curve *KoblitzCurve, bigX *big.Int, ybit bool) (*big.Int, error) {
+	var x fieldVal
+	x.SetByteSlice(bigX.Bytes())
+
+	// Compute x^3 + B mod p.
+	var x3 fieldVal
+	x3.SquareVal(&x).Mul(&x)
+	x3.Add(curve.fieldB).Normalize()
+
+	// Now calculate sqrt mod p of x^3 + B
+	// This code used to do a full sqrt based on tonelli/shanks,
+	// but this was replaced by the algorithms referenced in
+	// https://bitcointalk.org/index.php?topic=162805.msg1712294#msg1712294
+	var y fieldVal
+	y.SqrtVal(&x3).Normalize()
+	if ybit != y.IsOdd() {
+		y.Negate(1).Normalize()
+	}
+
+	// Check that y is a square root of x^3 + B.
+	var y2 fieldVal
+	y2.SquareVal(&y).Normalize()
+	if !y2.Equals(&x3) {
+		return nil, fmt.Errorf("invalid square root")
+	}
+
+	// Verify that y-coord has expected parity.
+	if ybit != y.IsOdd() {
+		return nil, fmt.Errorf("ybit doesn't match oddness")
+	}
+
+	return new(big.Int).SetBytes(y.Bytes()[:]), nil
+}
+
+const (
+	pubkeyCompressed   byte = 0x2 // y_bit + x coord
+	pubkeyUncompressed byte = 0x4 // x coord + y coord
+	pubkeyHybrid       byte = 0x6 // y_bit + x coord + y coord
+)
+
+// IsCompressedPubKey returns true the the passed serialized public key has
+// been encoded in compressed format, and false otherwise.
+func IsCompressedPubKey(pubKey []byte) bool {
+	// The public key is only compressed if it is the correct length and
+	// the format (first byte) is one of the compressed pubkey values.
+	return len(pubKey) == PubKeyBytesLenCompressed &&
+		(pubKey[0]&^byte(0x1) == pubkeyCompressed)
+}
+
+// ParsePubKey parses a public key for a koblitz curve from a bytestring into a
+// ecdsa.Publickey, verifying that it is valid. It supports compressed,
+// uncompressed and hybrid signature formats.
+func ParsePubKey(pubKeyStr []byte, curve *KoblitzCurve) (key *PublicKey, err error) {
+	pubkey := PublicKey{}
+	pubkey.Curve = curve
+
+	if len(pubKeyStr) == 0 {
+		return nil, errors.New("pubkey string is empty")
+	}
+
+	format := pubKeyStr[0]
+	ybit := (format & 0x1) == 0x1
+	format &= ^byte(0x1)
+
+	switch len(pubKeyStr) {
+	case PubKeyBytesLenUncompressed:
+		if format != pubkeyUncompressed && format != pubkeyHybrid {
+			return nil, fmt.Errorf("invalid magic in pubkey str: "+
+				"%d", pubKeyStr[0])
+		}
+
+		pubkey.X = new(big.Int).SetBytes(pubKeyStr[1:33])
+		pubkey.Y = new(big.Int).SetBytes(pubKeyStr[33:])
+		// hybrid keys have extra information, make use of it.
+		if format == pubkeyHybrid && ybit != isOdd(pubkey.Y) {
+			return nil, fmt.Errorf("ybit doesn't match oddness")
+		}
+
+		if pubkey.X.Cmp(pubkey.Curve.Params().P) >= 0 {
+			return nil, fmt.Errorf("pubkey X parameter is >= to P")
+		}
+		if pubkey.Y.Cmp(pubkey.Curve.Params().P) >= 0 {
+			return nil, fmt.Errorf("pubkey Y parameter is >= to P")
+		}
+		if !pubkey.Curve.IsOnCurve(pubkey.X, pubkey.Y) {
+			return nil, fmt.Errorf("pubkey isn't on secp256k1 curve")
+		}
+
+	case PubKeyBytesLenCompressed:
+		// format is 0x2 | solution, <X coordinate>
+		// solution determines which solution of the curve we use.
+		/// y^2 = x^3 + Curve.B
+		if format != pubkeyCompressed {
+			return nil, fmt.Errorf("invalid magic in compressed "+
+				"pubkey string: %d", pubKeyStr[0])
+		}
+		pubkey.X = new(big.Int).SetBytes(pubKeyStr[1:33])
+		pubkey.Y, err = decompressPoint(curve, pubkey.X, ybit)
+		if err != nil {
+			return nil, err
+		}
+
+	default: // wrong!
+		return nil, fmt.Errorf("invalid pub key length %d",
+			len(pubKeyStr))
+	}
+
+	return &pubkey, nil
+}
+
+// PublicKey is an ecdsa.PublicKey with additional functions to
+// serialize in uncompressed, compressed, and hybrid formats.
+type PublicKey ecdsa.PublicKey
+
+// ToECDSA returns the public key as a *ecdsa.PublicKey.
+func (p *PublicKey) ToECDSA() *ecdsa.PublicKey {
+	return (*ecdsa.PublicKey)(p)
+}
+
+// SerializeUncompressed serializes a public key in a 65-byte uncompressed
+// format.
+func (p *PublicKey) SerializeUncompressed() []byte {
+	b := make([]byte, 0, PubKeyBytesLenUncompressed)
+	b = append(b, pubkeyUncompressed)
+	b = paddedAppend(32, b, p.X.Bytes())
+	return paddedAppend(32, b, p.Y.Bytes())
+}
+
+// SerializeCompressed serializes a public key in a 33-byte compressed format.
+func (p *PublicKey) SerializeCompressed() []byte {
+	b := make([]byte, 0, PubKeyBytesLenCompressed)
+	format := pubkeyCompressed
+	if isOdd(p.Y) {
+		format |= 0x1
+	}
+	b = append(b, format)
+	return paddedAppend(32, b, p.X.Bytes())
+}
+
+// SerializeHybrid serializes a public key in a 65-byte hybrid format.
+func (p *PublicKey) SerializeHybrid() []byte {
+	b := make([]byte, 0, PubKeyBytesLenHybrid)
+	format := pubkeyHybrid
+	if isOdd(p.Y) {
+		format |= 0x1
+	}
+	b = append(b, format)
+	b = paddedAppend(32, b, p.X.Bytes())
+	return paddedAppend(32, b, p.Y.Bytes())
+}
+
+// IsEqual compares this PublicKey instance to the one passed, returning true if
+// both PublicKeys are equivalent. A PublicKey is equivalent to another, if they
+// both have the same X and Y coordinate.
+func (p *PublicKey) IsEqual(otherPubKey *PublicKey) bool {
+	return p.X.Cmp(otherPubKey.X) == 0 &&
+		p.Y.Cmp(otherPubKey.Y) == 0
+}
+
+// paddedAppend appends the src byte slice to dst, returning the new slice.
+// If the length of the source is smaller than the passed size, leading zero
+// bytes are appended to the dst slice before appending src.
+func paddedAppend(size uint, dst, src []byte) []byte {
+	for i := 0; i < int(size)-len(src); i++ {
+		dst = append(dst, 0)
+	}
+	return append(dst, src...)
+}

vendor/github.com/btcsuite/btcd/btcec/signature.go

@@ -0,0 +1,540 @@
+// Copyright (c) 2013-2017 The btcsuite developers
+// Use of this source code is governed by an ISC
+// license that can be found in the LICENSE file.
+
+package btcec
+
+import (
+	"bytes"
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/hmac"
+	"crypto/sha256"
+	"errors"
+	"fmt"
+	"hash"
+	"math/big"
+)
+
+// Errors returned by canonicalPadding.
+var (
+	errNegativeValue          = errors.New("value may be interpreted as negative")
+	errExcessivelyPaddedValue = errors.New("value is excessively padded")
+)
+
+// Signature is a type representing an ecdsa signature.
+type Signature struct {
+	R *big.Int
+	S *big.Int
+}
+
+var (
+	// Used in RFC6979 implementation when testing the nonce for correctness
+	one = big.NewInt(1)
+
+	// oneInitializer is used to fill a byte slice with byte 0x01.  It is provided
+	// here to avoid the need to create it multiple times.
+	oneInitializer = []byte{0x01}
+)
+
+// Serialize returns the ECDSA signature in the more strict DER format.  Note
+// that the serialized bytes returned do not include the appended hash type
+// used in Bitcoin signature scripts.
+//
+// encoding/asn1 is broken so we hand roll this output:
+//
+// 0x30 <length> 0x02 <length r> r 0x02 <length s> s
+func (sig *Signature) Serialize() []byte {
+	// low 'S' malleability breaker
+	sigS := sig.S
+	if sigS.Cmp(S256().halfOrder) == 1 {
+		sigS = new(big.Int).Sub(S256().N, sigS)
+	}
+	// Ensure the encoded bytes for the r and s values are canonical and
+	// thus suitable for DER encoding.
+	rb := canonicalizeInt(sig.R)
+	sb := canonicalizeInt(sigS)
+
+	// total length of returned signature is 1 byte for each magic and
+	// length (6 total), plus lengths of r and s
+	length := 6 + len(rb) + len(sb)
+	b := make([]byte, length)
+
+	b[0] = 0x30
+	b[1] = byte(length - 2)
+	b[2] = 0x02
+	b[3] = byte(len(rb))
+	offset := copy(b[4:], rb) + 4
+	b[offset] = 0x02
+	b[offset+1] = byte(len(sb))
+	copy(b[offset+2:], sb)
+	return b
+}
+
+// Verify calls ecdsa.Verify to verify the signature of hash using the public
+// key.  It returns true if the signature is valid, false otherwise.
+func (sig *Signature) Verify(hash []byte, pubKey *PublicKey) bool {
+	return ecdsa.Verify(pubKey.ToECDSA(), hash, sig.R, sig.S)
+}
+
+// IsEqual compares this Signature instance to the one passed, returning true
+// if both Signatures are equivalent. A signature is equivalent to another, if
+// they both have the same scalar value for R and S.
+func (sig *Signature) IsEqual(otherSig *Signature) bool {
+	return sig.R.Cmp(otherSig.R) == 0 &&
+		sig.S.Cmp(otherSig.S) == 0
+}
+
+// MinSigLen is the minimum length of a DER encoded signature and is when both R
+// and S are 1 byte each.
+// 0x30 + <1-byte> + 0x02 + 0x01 + <byte> + 0x2 + 0x01 + <byte>
+const MinSigLen = 8
+
+func parseSig(sigStr []byte, curve elliptic.Curve, der bool) (*Signature, error) {
+	// Originally this code used encoding/asn1 in order to parse the
+	// signature, but a number of problems were found with this approach.
+	// Despite the fact that signatures are stored as DER, the difference
+	// between go's idea of a bignum (and that they have sign) doesn't agree
+	// with the openssl one (where they do not). The above is true as of
+	// Go 1.1. In the end it was simpler to rewrite the code to explicitly
+	// understand the format which is this:
+	// 0x30 <length of whole message> <0x02> <length of R> <R> 0x2
+	// <length of S> <S>.
+
+	signature := &Signature{}
+
+	if len(sigStr) < MinSigLen {
+		return nil, errors.New("malformed signature: too short")
+	}
+	// 0x30
+	index := 0
+	if sigStr[index] != 0x30 {
+		return nil, errors.New("malformed signature: no header magic")
+	}
+	index++
+	// length of remaining message
+	siglen := sigStr[index]
+	index++
+
+	// siglen should be less than the entire message and greater than
+	// the minimal message size.
+	if int(siglen+2) > len(sigStr) || int(siglen+2) < MinSigLen {
+		return nil, errors.New("malformed signature: bad length")
+	}
+	// trim the slice we're working on so we only look at what matters.
+	sigStr = sigStr[:siglen+2]
+
+	// 0x02
+	if sigStr[index] != 0x02 {
+		return nil,
+			errors.New("malformed signature: no 1st int marker")
+	}
+	index++
+
+	// Length of signature R.
+	rLen := int(sigStr[index])
+	// must be positive, must be able to fit in another 0x2, <len> <s>
+	// hence the -3. We assume that the length must be at least one byte.
+	index++
+	if rLen <= 0 || rLen > len(sigStr)-index-3 {
+		return nil, errors.New("malformed signature: bogus R length")
+	}
+
+	// Then R itself.
+	rBytes := sigStr[index : index+rLen]
+	if der {
+		switch err := canonicalPadding(rBytes); err {
+		case errNegativeValue:
+			return nil, errors.New("signature R is negative")
+		case errExcessivelyPaddedValue:
+			return nil, errors.New("signature R is excessively padded")
+		}
+	}
+	signature.R = new(big.Int).SetBytes(rBytes)
+	index += rLen
+	// 0x02. length already checked in previous if.
+	if sigStr[index] != 0x02 {
+		return nil, errors.New("malformed signature: no 2nd int marker")
+	}
+	index++
+
+	// Length of signature S.
+	sLen := int(sigStr[index])
+	index++
+	// S should be the rest of the string.
+	if sLen <= 0 || sLen > len(sigStr)-index {
+		return nil, errors.New("malformed signature: bogus S length")
+	}
+
+	// Then S itself.
+	sBytes := sigStr[index : index+sLen]
+	if der {
+		switch err := canonicalPadding(sBytes); err {
+		case errNegativeValue:
+			return nil, errors.New("signature S is negative")
+		case errExcessivelyPaddedValue:
+			return nil, errors.New("signature S is excessively padded")
+		}
+	}
+	signature.S = new(big.Int).SetBytes(sBytes)
+	index += sLen
+
+	// sanity check length parsing
+	if index != len(sigStr) {
+		return nil, fmt.Errorf("malformed signature: bad final length %v != %v",
+			index, len(sigStr))
+	}
+
+	// Verify also checks this, but we can be more sure that we parsed
+	// correctly if we verify here too.
+	// FWIW the ecdsa spec states that R and S must be | 1, N - 1 |
+	// but crypto/ecdsa only checks for Sign != 0. Mirror that.
+	if signature.R.Sign() != 1 {
+		return nil, errors.New("signature R isn't 1 or more")
+	}
+	if signature.S.Sign() != 1 {
+		return nil, errors.New("signature S isn't 1 or more")
+	}
+	if signature.R.Cmp(curve.Params().N) >= 0 {
+		return nil, errors.New("signature R is >= curve.N")
+	}
+	if signature.S.Cmp(curve.Params().N) >= 0 {
+		return nil, errors.New("signature S is >= curve.N")
+	}
+
+	return signature, nil
+}
+
+// ParseSignature parses a signature in BER format for the curve type `curve'
+// into a Signature type, perfoming some basic sanity checks.  If parsing
+// according to the more strict DER format is needed, use ParseDERSignature.
+func ParseSignature(sigStr []byte, curve elliptic.Curve) (*Signature, error) {
+	return parseSig(sigStr, curve, false)
+}
+
+// ParseDERSignature parses a signature in DER format for the curve type
+// `curve` into a Signature type.  If parsing according to the less strict
+// BER format is needed, use ParseSignature.
+func ParseDERSignature(sigStr []byte, curve elliptic.Curve) (*Signature, error) {
+	return parseSig(sigStr, curve, true)
+}
+
+// canonicalizeInt returns the bytes for the passed big integer adjusted as
+// necessary to ensure that a big-endian encoded integer can't possibly be
+// misinterpreted as a negative number.  This can happen when the most
+// significant bit is set, so it is padded by a leading zero byte in this case.
+// Also, the returned bytes will have at least a single byte when the passed
+// value is 0.  This is required for DER encoding.
+func canonicalizeInt(val *big.Int) []byte {
+	b := val.Bytes()
+	if len(b) == 0 {
+		b = []byte{0x00}
+	}
+	if b[0]&0x80 != 0 {
+		paddedBytes := make([]byte, len(b)+1)
+		copy(paddedBytes[1:], b)
+		b = paddedBytes
+	}
+	return b
+}
+
+// canonicalPadding checks whether a big-endian encoded integer could
+// possibly be misinterpreted as a negative number (even though OpenSSL
+// treats all numbers as unsigned), or if there is any unnecessary
+// leading zero padding.
+func canonicalPadding(b []byte) error {
+	switch {
+	case b[0]&0x80 == 0x80:
+		return errNegativeValue
+	case len(b) > 1 && b[0] == 0x00 && b[1]&0x80 != 0x80:
+		return errExcessivelyPaddedValue
+	default:
+		return nil
+	}
+}
+
+// hashToInt converts a hash value to an integer. There is some disagreement
+// about how this is done. [NSA] suggests that this is done in the obvious
+// manner, but [SECG] truncates the hash to the bit-length of the curve order
+// first. We follow [SECG] because that's what OpenSSL does. Additionally,
+// OpenSSL right shifts excess bits from the number if the hash is too large
+// and we mirror that too.
+// This is borrowed from crypto/ecdsa.
+func hashToInt(hash []byte, c elliptic.Curve) *big.Int {
+	orderBits := c.Params().N.BitLen()
+	orderBytes := (orderBits + 7) / 8
+	if len(hash) > orderBytes {
+		hash = hash[:orderBytes]
+	}
+
+	ret := new(big.Int).SetBytes(hash)
+	excess := len(hash)*8 - orderBits
+	if excess > 0 {
+		ret.Rsh(ret, uint(excess))
+	}
+	return ret
+}
+
+// recoverKeyFromSignature recovers a public key from the signature "sig" on the
+// given message hash "msg". Based on the algorithm found in section 4.1.6 of
+// SEC 1 Ver 2.0, page 47-48 (53 and 54 in the pdf). This performs the details
+// in the inner loop in Step 1. The counter provided is actually the j parameter
+// of the loop * 2 - on the first iteration of j we do the R case, else the -R
+// case in step 1.6. This counter is used in the bitcoin compressed signature
+// format and thus we match bitcoind's behaviour here.
+func recoverKeyFromSignature(curve *KoblitzCurve, sig *Signature, msg []byte,
+	iter int, doChecks bool) (*PublicKey, error) {
+	// 1.1 x = (n * i) + r
+	Rx := new(big.Int).Mul(curve.Params().N,
+		new(big.Int).SetInt64(int64(iter/2)))
+	Rx.Add(Rx, sig.R)
+	if Rx.Cmp(curve.Params().P) != -1 {
+		return nil, errors.New("calculated Rx is larger than curve P")
+	}
+
+	// convert 02<Rx> to point R. (step 1.2 and 1.3). If we are on an odd
+	// iteration then 1.6 will be done with -R, so we calculate the other
+	// term when uncompressing the point.
+	Ry, err := decompressPoint(curve, Rx, iter%2 == 1)
+	if err != nil {
+		return nil, err
+	}
+
+	// 1.4 Check n*R is point at infinity
+	if doChecks {
+		nRx, nRy := curve.ScalarMult(Rx, Ry, curve.Params().N.Bytes())
+		if nRx.Sign() != 0 || nRy.Sign() != 0 {
+			return nil, errors.New("n*R does not equal the point at infinity")
+		}
+	}
+
+	// 1.5 calculate e from message using the same algorithm as ecdsa
+	// signature calculation.
+	e := hashToInt(msg, curve)
+
+	// Step 1.6.1:
+	// We calculate the two terms sR and eG separately multiplied by the
+	// inverse of r (from the signature). We then add them to calculate
+	// Q = r^-1(sR-eG)
+	invr := new(big.Int).ModInverse(sig.R, curve.Params().N)
+
+	// first term.
+	invrS := new(big.Int).Mul(invr, sig.S)
+	invrS.Mod(invrS, curve.Params().N)
+	sRx, sRy := curve.ScalarMult(Rx, Ry, invrS.Bytes())
+
+	// second term.
+	e.Neg(e)
+	e.Mod(e, curve.Params().N)
+	e.Mul(e, invr)
+	e.Mod(e, curve.Params().N)
+	minuseGx, minuseGy := curve.ScalarBaseMult(e.Bytes())
+
+	// TODO: this would be faster if we did a mult and add in one
+	// step to prevent the jacobian conversion back and forth.
+	Qx, Qy := curve.Add(sRx, sRy, minuseGx, minuseGy)
+
+	return &PublicKey{
+		Curve: curve,
+		X:     Qx,
+		Y:     Qy,
+	}, nil
+}
+
+// SignCompact produces a compact signature of the data in hash with the given
+// private key on the given koblitz curve. The isCompressed  parameter should
+// be used to detail if the given signature should reference a compressed
+// public key or not. If successful the bytes of the compact signature will be
+// returned in the format:
+// <(byte of 27+public key solution)+4 if compressed >< padded bytes for signature R><padded bytes for signature S>
+// where the R and S parameters are padde up to the bitlengh of the curve.
+func SignCompact(curve *KoblitzCurve, key *PrivateKey,
+	hash []byte, isCompressedKey bool) ([]byte, error) {
+	sig, err := key.Sign(hash)
+	if err != nil {
+		return nil, err
+	}
+
+	// bitcoind checks the bit length of R and S here. The ecdsa signature
+	// algorithm returns R and S mod N therefore they will be the bitsize of
+	// the curve, and thus correctly sized.
+	for i := 0; i < (curve.H+1)*2; i++ {
+		pk, err := recoverKeyFromSignature(curve, sig, hash, i, true)
+		if err == nil && pk.X.Cmp(key.X) == 0 && pk.Y.Cmp(key.Y) == 0 {
+			result := make([]byte, 1, 2*curve.byteSize+1)
+			result[0] = 27 + byte(i)
+			if isCompressedKey {
+				result[0] += 4
+			}
+			// Not sure this needs rounding but safer to do so.
+			curvelen := (curve.BitSize + 7) / 8
+
+			// Pad R and S to curvelen if needed.
+			bytelen := (sig.R.BitLen() + 7) / 8
+			if bytelen < curvelen {
+				result = append(result,
+					make([]byte, curvelen-bytelen)...)
+			}
+			result = append(result, sig.R.Bytes()...)
+
+			bytelen = (sig.S.BitLen() + 7) / 8
+			if bytelen < curvelen {
+				result = append(result,
+					make([]byte, curvelen-bytelen)...)
+			}
+			result = append(result, sig.S.Bytes()...)
+
+			return result, nil
+		}
+	}
+
+	return nil, errors.New("no valid solution for pubkey found")
+}
+
+// RecoverCompact verifies the compact signature "signature" of "hash" for the
+// Koblitz curve in "curve". If the signature matches then the recovered public
+// key will be returned as well as a boolen if the original key was compressed
+// or not, else an error will be returned.
+func RecoverCompact(curve *KoblitzCurve, signature,
+	hash []byte) (*PublicKey, bool, error) {
+	bitlen := (curve.BitSize + 7) / 8
+	if len(signature) != 1+bitlen*2 {
+		return nil, false, errors.New("invalid compact signature size")
+	}
+
+	iteration := int((signature[0] - 27) & ^byte(4))
+
+	// format is <header byte><bitlen R><bitlen S>
+	sig := &Signature{
+		R: new(big.Int).SetBytes(signature[1 : bitlen+1]),
+		S: new(big.Int).SetBytes(signature[bitlen+1:]),
+	}
+	// The iteration used here was encoded
+	key, err := recoverKeyFromSignature(curve, sig, hash, iteration, false)
+	if err != nil {
+		return nil, false, err
+	}
+
+	return key, ((signature[0] - 27) & 4) == 4, nil
+}
+
+// signRFC6979 generates a deterministic ECDSA signature according to RFC 6979 and BIP 62.
+func signRFC6979(privateKey *PrivateKey, hash []byte) (*Signature, error) {
+
+	privkey := privateKey.ToECDSA()
+	N := S256().N
+	halfOrder := S256().halfOrder
+	k := nonceRFC6979(privkey.D, hash)
+	inv := new(big.Int).ModInverse(k, N)
+	r, _ := privkey.Curve.ScalarBaseMult(k.Bytes())
+	r.Mod(r, N)
+
+	if r.Sign() == 0 {
+		return nil, errors.New("calculated R is zero")
+	}
+
+	e := hashToInt(hash, privkey.Curve)
+	s := new(big.Int).Mul(privkey.D, r)
+	s.Add(s, e)
+	s.Mul(s, inv)
+	s.Mod(s, N)
+
+	if s.Cmp(halfOrder) == 1 {
+		s.Sub(N, s)
+	}
+	if s.Sign() == 0 {
+		return nil, errors.New("calculated S is zero")
+	}
+	return &Signature{R: r, S: s}, nil
+}
+
+// nonceRFC6979 generates an ECDSA nonce (`k`) deterministically according to RFC 6979.
+// It takes a 32-byte hash as an input and returns 32-byte nonce to be used in ECDSA algorithm.
+func nonceRFC6979(privkey *big.Int, hash []byte) *big.Int {
+
+	curve := S256()
+	q := curve.Params().N
+	x := privkey
+	alg := sha256.New
+
+	qlen := q.BitLen()
+	holen := alg().Size()
+	rolen := (qlen + 7) >> 3
+	bx := append(int2octets(x, rolen), bits2octets(hash, curve, rolen)...)
+
+	// Step B
+	v := bytes.Repeat(oneInitializer, holen)
+
+	// Step C (Go zeroes the all allocated memory)
+	k := make([]byte, holen)
+
+	// Step D
+	k = mac(alg, k, append(append(v, 0x00), bx...))
+
+	// Step E
+	v = mac(alg, k, v)
+
+	// Step F
+	k = mac(alg, k, append(append(v, 0x01), bx...))
+
+	// Step G
+	v = mac(alg, k, v)
+
+	// Step H
+	for {
+		// Step H1
+		var t []byte
+
+		// Step H2
+		for len(t)*8 < qlen {
+			v = mac(alg, k, v)
+			t = append(t, v...)
+		}
+
+		// Step H3
+		secret := hashToInt(t, curve)
+		if secret.Cmp(one) >= 0 && secret.Cmp(q) < 0 {
+			return secret
+		}
+		k = mac(alg, k, append(v, 0x00))
+		v = mac(alg, k, v)
+	}
+}
+
+// mac returns an HMAC of the given key and message.
+func mac(alg func() hash.Hash, k, m []byte) []byte {
+	h := hmac.New(alg, k)
+	h.Write(m)
+	return h.Sum(nil)
+}
+
+// https://tools.ietf.org/html/rfc6979#section-2.3.3
+func int2octets(v *big.Int, rolen int) []byte {
+	out := v.Bytes()
+
+	// left pad with zeros if it's too short
+	if len(out) < rolen {
+		out2 := make([]byte, rolen)
+		copy(out2[rolen-len(out):], out)
+		return out2
+	}
+
+	// drop most significant bytes if it's too long
+	if len(out) > rolen {
+		out2 := make([]byte, rolen)
+		copy(out2, out[len(out)-rolen:])
+		return out2
+	}
+
+	return out
+}
+
+// https://tools.ietf.org/html/rfc6979#section-2.3.4
+func bits2octets(in []byte, curve elliptic.Curve, rolen int) []byte {
+	z1 := hashToInt(in, curve)
+	z2 := new(big.Int).Sub(z1, curve.Params().N)
+	if z2.Sign() < 0 {
+		return int2octets(z1, rolen)
+	}
+	return int2octets(z2, rolen)
+}

vendor/github.com/crackcomm/go-gitignore/.gitignore

@@ -0,0 +1,28 @@
+# Package test fixtures
+test_fixtures
+
+# Compiled Object files, Static and Dynamic libs (Shared Objects)
+*.o
+*.a
+*.so
+
+# Folders
+_obj
+_test
+
+# Architecture specific extensions/prefixes
+*.[568vq]
+[568vq].out
+
+*.cgo1.go
+*.cgo2.c
+_cgo_defun.c
+_cgo_gotypes.go
+_cgo_export.*
+
+_testmain.go
+
+*.exe
+*.test
+*.prof
+

vendor/github.com/crackcomm/go-gitignore/.travis.yml

@@ -0,0 +1,18 @@
+language: go
+
+go:
+  - 1.3
+  - tip
+
+env:
+  - "PATH=$HOME/gopath/bin:$PATH"
+
+before_install:
+  - go get github.com/stretchr/testify/assert
+  - go get github.com/axw/gocov/gocov
+  - go get github.com/mattn/goveralls
+  - if ! go get code.google.com/p/go.tools/cmd/cover; then go get golang.org/x/tools/cmd/cover; fi
+
+script:
+  - go test -v -covermode=count -coverprofile=coverage.out
+  - goveralls -coverprofile=coverage.out -service travis-ci -repotoken $COVERALLS_TOKEN

vendor/github.com/crackcomm/go-gitignore/LICENSE

@@ -0,0 +1,22 @@
+The MIT License (MIT)
+
+Copyright (c) 2015 Shaba Abhiram
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+

vendor/github.com/crackcomm/go-gitignore/README.md

@@ -0,0 +1,17 @@
+# go-git-ignore
+
+[![Build Status](https://travis-ci.org/sabhiram/go-git-ignore.svg)](https://travis-ci.org/sabhiram/go-git-ignore) [![Coverage Status](https://coveralls.io/repos/sabhiram/go-git-ignore/badge.png?branch=master)](https://coveralls.io/r/sabhiram/go-git-ignore?branch=master)
+
+A gitignore parser for `Go`
+
+## Install
+
+```shell
+go get github.com/sabhiram/go-git-ignore
+```
+
+## Usage
+
+```shell
+TODO
+```

vendor/github.com/crackcomm/go-gitignore/ignore.go

@@ -0,0 +1,219 @@
+/*
+ignore is a library which returns a new ignorer object which can
+test against various paths. This is particularly useful when trying
+to filter files based on a .gitignore document
+
+The rules for parsing the input file are the same as the ones listed
+in the Git docs here: http://git-scm.com/docs/gitignore
+
+The summarized version of the same has been copied here:
+
+    1. A blank line matches no files, so it can serve as a separator
+       for readability.
+    2. A line starting with # serves as a comment. Put a backslash ("\")
+       in front of the first hash for patterns that begin with a hash.
+    3. Trailing spaces are ignored unless they are quoted with backslash ("\").
+    4. An optional prefix "!" which negates the pattern; any matching file
+       excluded by a previous pattern will become included again. It is not
+       possible to re-include a file if a parent directory of that file is
+       excluded. Git doesn’t list excluded directories for performance reasons,
+       so any patterns on contained files have no effect, no matter where they
+       are defined. Put a backslash ("\") in front of the first "!" for
+       patterns that begin with a literal "!", for example, "\!important!.txt".
+    5. If the pattern ends with a slash, it is removed for the purpose of the
+       following description, but it would only find a match with a directory.
+       In other words, foo/ will match a directory foo and paths underneath it,
+       but will not match a regular file or a symbolic link foo (this is
+       consistent with the way how pathspec works in general in Git).
+    6. If the pattern does not contain a slash /, Git treats it as a shell glob
+       pattern and checks for a match against the pathname relative to the
+       location of the .gitignore file (relative to the toplevel of the work
+       tree if not from a .gitignore file).
+    7. Otherwise, Git treats the pattern as a shell glob suitable for
+       consumption by fnmatch(3) with the FNM_PATHNAME flag: wildcards in the
+       pattern will not match a / in the pathname. For example,
+       "Documentation/*.html" matches "Documentation/git.html" but not
+       "Documentation/ppc/ppc.html" or "tools/perf/Documentation/perf.html".
+    8. A leading slash matches the beginning of the pathname. For example,
+       "/*.c" matches "cat-file.c" but not "mozilla-sha1/sha1.c".
+    9. Two consecutive asterisks ("**") in patterns matched against full
+       pathname may have special meaning:
+        i.   A leading "**" followed by a slash means match in all directories.
+             For example, "** /foo" matches file or directory "foo" anywhere,
+             the same as pattern "foo". "** /foo/bar" matches file or directory
+             "bar" anywhere that is directly under directory "foo".
+        ii.  A trailing "/**" matches everything inside. For example, "abc/**"
+             matches all files inside directory "abc", relative to the location
+             of the .gitignore file, with infinite depth.
+        iii. A slash followed by two consecutive asterisks then a slash matches
+             zero or more directories. For example, "a/** /b" matches "a/b",
+             "a/x/b", "a/x/y/b" and so on.
+        iv.  Other consecutive asterisks are considered invalid. */
+package ignore
+
+import (
+	"io/ioutil"
+	"os"
+	"regexp"
+	"strings"
+)
+
+////////////////////////////////////////////////////////////
+
+// An IgnoreParser is an interface which exposes two methods:
+//   MatchesPath() - Returns true if the path is targeted by the patterns compiled in the GitIgnore structure
+type IgnoreParser interface {
+	MatchesPath(f string) bool
+}
+
+////////////////////////////////////////////////////////////
+
+// This function pretty much attempts to mimic the parsing rules
+// listed above at the start of this file
+func getPatternFromLine(line string) (*regexp.Regexp, bool) {
+	// Trim OS-specific carriage returns.
+	line = strings.TrimRight(line, "\r")
+
+	// Strip comments [Rule 2]
+	if strings.HasPrefix(line, `#`) {
+		return nil, false
+	}
+
+	// Trim string [Rule 3]
+	// TODO: Handle [Rule 3], when the " " is escaped with a \
+	line = strings.Trim(line, " ")
+
+	// Exit for no-ops and return nil which will prevent us from
+	// appending a pattern against this line
+	if line == "" {
+		return nil, false
+	}
+
+	// TODO: Handle [Rule 4] which negates the match for patterns leading with "!"
+	negatePattern := false
+	if line[0] == '!' {
+		negatePattern = true
+		line = line[1:]
+	}
+
+	// Handle [Rule 2, 4], when # or ! is escaped with a \
+	// Handle [Rule 4] once we tag negatePattern, strip the leading ! char
+	if regexp.MustCompile(`^(\#|\!)`).MatchString(line) {
+		line = line[1:]
+	}
+
+	// If we encounter a foo/*.blah in a folder, prepend the / char
+	if regexp.MustCompile(`([^\/+])/.*\*\.`).MatchString(line) && line[0] != '/' {
+		line = "/" + line
+	}
+
+	// Handle escaping the "." char
+	line = regexp.MustCompile(`\.`).ReplaceAllString(line, `\.`)
+
+	magicStar := "#$~"
+
+	// Handle "/**/" usage
+	if strings.HasPrefix(line, "/**/") {
+		line = line[1:]
+	}
+	line = regexp.MustCompile(`/\*\*/`).ReplaceAllString(line, `(/|/.+/)`)
+	line = regexp.MustCompile(`\*\*/`).ReplaceAllString(line, `(|.`+magicStar+`/)`)
+	line = regexp.MustCompile(`/\*\*`).ReplaceAllString(line, `(|/.`+magicStar+`)`)
+
+	// Handle escaping the "*" char
+	line = regexp.MustCompile(`\\\*`).ReplaceAllString(line, `\`+magicStar)
+	line = regexp.MustCompile(`\*`).ReplaceAllString(line, `([^/]*)`)
+
+	// Handle escaping the "?" char
+	line = strings.Replace(line, "?", `\?`, -1)
+
+	line = strings.Replace(line, magicStar, "*", -1)
+
+	// Temporary regex
+	var expr = ""
+	if strings.HasSuffix(line, "/") {
+		expr = line + "(|.*)$"
+	} else {
+		expr = line + "(|/.*)$"
+	}
+	if strings.HasPrefix(expr, "/") {
+		expr = "^(|/)" + expr[1:]
+	} else {
+		expr = "^(|.*/)" + expr
+	}
+	pattern, _ := regexp.Compile(expr)
+
+	return pattern, negatePattern
+}
+
+////////////////////////////////////////////////////////////
+
+// GitIgnore is a struct which contains a slice of regexp.Regexp
+// patterns
+type GitIgnore struct {
+	patterns []*regexp.Regexp // List of regexp patterns which this ignore file applies
+	negate   []bool           // List of booleans which determine if the pattern is negated
+}
+
+// Accepts a variadic set of strings, and returns a GitIgnore object which
+// converts and appends the lines in the input to regexp.Regexp patterns
+// held within the GitIgnore objects "patterns" field
+func CompileIgnoreLines(lines ...string) (*GitIgnore, error) {
+	g := new(GitIgnore)
+	for _, line := range lines {
+		pattern, negatePattern := getPatternFromLine(line)
+		if pattern != nil {
+			g.patterns = append(g.patterns, pattern)
+			g.negate = append(g.negate, negatePattern)
+		}
+	}
+	return g, nil
+}
+
+// Accepts a ignore file as the input, parses the lines out of the file
+// and invokes the CompileIgnoreLines method
+func CompileIgnoreFile(fpath string) (*GitIgnore, error) {
+	buffer, error := ioutil.ReadFile(fpath)
+	if error == nil {
+		s := strings.Split(string(buffer), "\n")
+		return CompileIgnoreLines(s...)
+	}
+	return nil, error
+}
+
+// Accepts a ignore file as the input, parses the lines out of the file
+// and invokes the CompileIgnoreLines method with additional lines
+func CompileIgnoreFileAndLines(fpath string, lines ...string) (*GitIgnore, error) {
+	buffer, error := ioutil.ReadFile(fpath)
+	if error == nil {
+		s := strings.Split(string(buffer), "\n")
+		return CompileIgnoreLines(append(s, lines...)...)
+	}
+	return nil, error
+}
+
+////////////////////////////////////////////////////////////
+
+// MatchesPath is an interface function for the IgnoreParser interface.
+// It returns true if the given GitIgnore structure would target a given
+// path string "f"
+func (g GitIgnore) MatchesPath(f string) bool {
+	// Replace OS-specific path separator.
+	f = strings.Replace(f, string(os.PathSeparator), "/", -1)
+
+	matchesPath := false
+	for idx, pattern := range g.patterns {
+		if pattern.MatchString(f) {
+			// If this is a regular target (not negated with a gitignore exclude "!" etc)
+			if !g.negate[idx] {
+				matchesPath = true
+				// Negated pattern, and matchesPath is already set
+			} else if matchesPath {
+				matchesPath = false
+			}
+		}
+	}
+	return matchesPath
+}
+
+////////////////////////////////////////////////////////////

vendor/github.com/davidlazar/go-crypto/LICENSE

@@ -0,0 +1,19 @@
+Copyright (c) 2016 David Lazar <lazard@mit.edu>
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

vendor/github.com/davidlazar/go-crypto/salsa20/salsa20.go

@@ -0,0 +1,85 @@
+package salsa20
+
+import (
+	"crypto/cipher"
+	"encoding/binary"
+
+	"golang.org/x/crypto/salsa20/salsa"
+)
+
+const BlockSize = 64
+
+type salsaCipher struct {
+	key     *[32]byte
+	nonce   [8]byte
+	x       [BlockSize]byte
+	nx      int
+	counter uint64
+}
+
+func New(key *[32]byte, nonce []byte) cipher.Stream {
+	c := new(salsaCipher)
+
+	if len(nonce) == 24 {
+		var subKey [32]byte
+		var hNonce [16]byte
+		copy(hNonce[:], nonce[:16])
+		salsa.HSalsa20(&subKey, &hNonce, key, &salsa.Sigma)
+		copy(c.nonce[:], nonce[16:])
+		c.key = &subKey
+	} else if len(nonce) == 8 {
+		c.key = key
+		copy(c.nonce[:], nonce)
+	} else {
+		panic("salsa20: nonce must be 8 or 24 bytes")
+	}
+	return c
+}
+
+func (c *salsaCipher) XORKeyStream(dst, src []byte) {
+	if len(dst) < len(src) {
+		src = src[:len(dst)]
+	}
+	if c.nx > 0 {
+		n := xorBytes(dst, src, c.x[c.nx:])
+		c.nx += n
+		if c.nx == BlockSize {
+			c.nx = 0
+		}
+		src = src[n:]
+		dst = dst[n:]
+	}
+	if len(src) > BlockSize {
+		n := len(src) &^ (BlockSize - 1)
+		c.blocks(dst, src[:n])
+		src = src[n:]
+		dst = dst[n:]
+	}
+	if len(src) > 0 {
+		c.nx = copy(c.x[:], src)
+		for i := c.nx; i < len(c.x); i++ {
+			c.x[i] = 0
+		}
+		c.blocks(c.x[:], c.x[:])
+		copy(dst, c.x[:c.nx])
+	}
+}
+
+func (c *salsaCipher) blocks(dst, src []byte) {
+	var nonce [16]byte
+	copy(nonce[:], c.nonce[:])
+	binary.LittleEndian.PutUint64(nonce[8:], c.counter)
+	salsa.XORKeyStream(dst, src, &nonce, c.key)
+	c.counter += uint64(len(src)) / 64
+}
+
+func xorBytes(dst, a, b []byte) int {
+	n := len(a)
+	if len(b) < n {
+		n = len(b)
+	}
+	for i := 0; i < n; i++ {
+		dst[i] = a[i] ^ b[i]
+	}
+	return n
+}

vendor/github.com/flynn/noise/CONTRIBUTING.md

@@ -0,0 +1 @@
+See the [Flynn contributing guide](https://flynn.io/docs/contributing).

vendor/github.com/flynn/noise/LICENSE

@@ -0,0 +1,29 @@
+Flynn® is a trademark of Prime Directive, Inc.
+
+Copyright (c) 2015 Prime Directive, Inc. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Prime Directive, Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/github.com/flynn/noise/README.md

@@ -0,0 +1,5 @@
+# noise [![Go Reference](https://pkg.go.dev/badge/github.com/flynn/noise.svg)](https://pkg.go.dev/github.com/flynn/noise) [![CI Status](https://github.com/flynn/noise/actions/workflows/ci.yml/badge.svg)](https://github.com/flynn/noise/actions)
+
+This is a Go package that implements the [Noise Protocol
+Framework](https://noiseprotocol.org). See [the
+documentation](https://pkg.go.dev/github.com/flynn/noise) for usage information.

vendor/github.com/flynn/noise/cipher_suite.go

@@ -0,0 +1,224 @@
+package noise
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"crypto/sha256"
+	"crypto/sha512"
+	"encoding/binary"
+	"hash"
+	"io"
+
+	"golang.org/x/crypto/blake2b"
+	"golang.org/x/crypto/blake2s"
+	"golang.org/x/crypto/chacha20poly1305"
+	"golang.org/x/crypto/curve25519"
+)
+
+// A DHKey is a keypair used for Diffie-Hellman key agreement.
+type DHKey struct {
+	Private []byte
+	Public  []byte
+}
+
+// A DHFunc implements Diffie-Hellman key agreement.
+type DHFunc interface {
+	// GenerateKeypair generates a new keypair using random as a source of
+	// entropy.
+	GenerateKeypair(random io.Reader) (DHKey, error)
+
+	// DH performs a Diffie-Hellman calculation between the provided private and
+	// public keys and returns the result.
+	DH(privkey, pubkey []byte) ([]byte, error)
+
+	// DHLen is the number of bytes returned by DH.
+	DHLen() int
+
+	// DHName is the name of the DH function.
+	DHName() string
+}
+
+// A HashFunc implements a cryptographic hash function.
+type HashFunc interface {
+	// Hash returns a hash state.
+	Hash() hash.Hash
+
+	// HashName is the name of the hash function.
+	HashName() string
+}
+
+// A CipherFunc implements an AEAD symmetric cipher.
+type CipherFunc interface {
+	// Cipher initializes the algorithm with the provided key and returns a Cipher.
+	Cipher(k [32]byte) Cipher
+
+	// CipherName is the name of the cipher.
+	CipherName() string
+}
+
+// A Cipher is a AEAD cipher that has been initialized with a key.
+type Cipher interface {
+	// Encrypt encrypts the provided plaintext with a nonce and then appends the
+	// ciphertext to out along with an authentication tag over the ciphertext
+	// and optional authenticated data.
+	Encrypt(out []byte, n uint64, ad, plaintext []byte) []byte
+
+	// Decrypt authenticates the ciphertext and optional authenticated data and
+	// then decrypts the provided ciphertext using the provided nonce and
+	// appends it to out.
+	Decrypt(out []byte, n uint64, ad, ciphertext []byte) ([]byte, error)
+}
+
+// A CipherSuite is a set of cryptographic primitives used in a Noise protocol.
+// It should be constructed with NewCipherSuite.
+type CipherSuite interface {
+	DHFunc
+	CipherFunc
+	HashFunc
+	Name() []byte
+}
+
+// NewCipherSuite returns a CipherSuite constructed from the specified
+// primitives.
+func NewCipherSuite(dh DHFunc, c CipherFunc, h HashFunc) CipherSuite {
+	return ciphersuite{
+		DHFunc:     dh,
+		CipherFunc: c,
+		HashFunc:   h,
+		name:       []byte(dh.DHName() + "_" + c.CipherName() + "_" + h.HashName()),
+	}
+}
+
+type ciphersuite struct {
+	DHFunc
+	CipherFunc
+	HashFunc
+	name []byte
+}
+
+func (s ciphersuite) Name() []byte { return s.name }
+
+// DH25519 is the Curve25519 ECDH function.
+var DH25519 DHFunc = dh25519{}
+
+type dh25519 struct{}
+
+func (dh25519) GenerateKeypair(rng io.Reader) (DHKey, error) {
+	privkey := make([]byte, 32)
+	if rng == nil {
+		rng = rand.Reader
+	}
+	if _, err := io.ReadFull(rng, privkey); err != nil {
+		return DHKey{}, err
+	}
+	pubkey, err := curve25519.X25519(privkey, curve25519.Basepoint)
+	if err != nil {
+		return DHKey{}, err
+	}
+	return DHKey{Private: privkey, Public: pubkey}, nil
+}
+
+func (dh25519) DH(privkey, pubkey []byte) ([]byte, error) {
+	return curve25519.X25519(privkey, pubkey)
+}
+
+func (dh25519) DHLen() int     { return 32 }
+func (dh25519) DHName() string { return "25519" }
+
+type cipherFn struct {
+	fn   func([32]byte) Cipher
+	name string
+}
+
+func (c cipherFn) Cipher(k [32]byte) Cipher { return c.fn(k) }
+func (c cipherFn) CipherName() string       { return c.name }
+
+// CipherAESGCM is the AES256-GCM AEAD cipher.
+var CipherAESGCM CipherFunc = cipherFn{cipherAESGCM, "AESGCM"}
+
+func cipherAESGCM(k [32]byte) Cipher {
+	c, err := aes.NewCipher(k[:])
+	if err != nil {
+		panic(err)
+	}
+	gcm, err := cipher.NewGCM(c)
+	if err != nil {
+		panic(err)
+	}
+	return aeadCipher{
+		gcm,
+		func(n uint64) []byte {
+			var nonce [12]byte
+			binary.BigEndian.PutUint64(nonce[4:], n)
+			return nonce[:]
+		},
+	}
+}
+
+// CipherChaChaPoly is the ChaCha20-Poly1305 AEAD cipher construction.
+var CipherChaChaPoly CipherFunc = cipherFn{cipherChaChaPoly, "ChaChaPoly"}
+
+func cipherChaChaPoly(k [32]byte) Cipher {
+	c, err := chacha20poly1305.New(k[:])
+	if err != nil {
+		panic(err)
+	}
+	return aeadCipher{
+		c,
+		func(n uint64) []byte {
+			var nonce [12]byte
+			binary.LittleEndian.PutUint64(nonce[4:], n)
+			return nonce[:]
+		},
+	}
+}
+
+type aeadCipher struct {
+	cipher.AEAD
+	nonce func(uint64) []byte
+}
+
+func (c aeadCipher) Encrypt(out []byte, n uint64, ad, plaintext []byte) []byte {
+	return c.Seal(out, c.nonce(n), plaintext, ad)
+}
+
+func (c aeadCipher) Decrypt(out []byte, n uint64, ad, ciphertext []byte) ([]byte, error) {
+	return c.Open(out, c.nonce(n), ciphertext, ad)
+}
+
+type hashFn struct {
+	fn   func() hash.Hash
+	name string
+}
+
+func (h hashFn) Hash() hash.Hash  { return h.fn() }
+func (h hashFn) HashName() string { return h.name }
+
+// HashSHA256 is the SHA-256 hash function.
+var HashSHA256 HashFunc = hashFn{sha256.New, "SHA256"}
+
+// HashSHA512 is the SHA-512 hash function.
+var HashSHA512 HashFunc = hashFn{sha512.New, "SHA512"}
+
+func blake2bNew() hash.Hash {
+	h, err := blake2b.New512(nil)
+	if err != nil {
+		panic(err)
+	}
+	return h
+}
+
+// HashBLAKE2b is the BLAKE2b hash function.
+var HashBLAKE2b HashFunc = hashFn{blake2bNew, "BLAKE2b"}
+
+func blake2sNew() hash.Hash {
+	h, err := blake2s.New256(nil)
+	if err != nil {
+		panic(err)
+	}
+	return h
+}
+
+// HashBLAKE2s is the BLAKE2s hash function.
+var HashBLAKE2s HashFunc = hashFn{blake2sNew, "BLAKE2s"}

vendor/github.com/flynn/noise/go.mod

@@ -0,0 +1,8 @@
+module github.com/flynn/noise
+
+go 1.16
+
+require (
+	golang.org/x/crypto v0.0.0-20210322153248-0c34fe9e7dc2
+	gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c
+)

vendor/github.com/flynn/noise/go.sum

@@ -0,0 +1,15 @@
+github.com/kr/pretty v0.2.1 h1:Fmg33tUaq4/8ym9TJN1x7sLJnHVwhP33CNkpYV/7rwI=
+github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfnI=
+github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
+github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
+github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
+golang.org/x/crypto v0.0.0-20210322153248-0c34fe9e7dc2 h1:It14KIkyBFYkHkwZ7k45minvA9aorojkyjGk9KJ5B/w=
+golang.org/x/crypto v0.0.0-20210322153248-0c34fe9e7dc2/go.mod h1:T9bdIzuCu7OtxOm1hfPfRQxPLYneinmdGuTeoZ9dtd4=
+golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68 h1:nxC68pudNYkKU6jWhgrqdreuFiOQWj1Fs7T3VrH4Pjw=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c h1:Hei/4ADfdWqJk1ZMxUNpqntNwaWcugrBjAiHlqqRiVk=
+gopkg.in/check.v1 v1.0.0-20201130134442-10cb98267c6c/go.mod h1:JHkPIbrfpd72SG/EVd6muEfDQjcINNoR0C8j2r3qZ4Q=

vendor/github.com/flynn/noise/hkdf.go

@@ -0,0 +1,49 @@
+package noise
+
+import (
+	"crypto/hmac"
+	"hash"
+)
+
+func hkdf(h func() hash.Hash, outputs int, out1, out2, out3, chainingKey, inputKeyMaterial []byte) ([]byte, []byte, []byte) {
+	if len(out1) > 0 {
+		panic("len(out1) > 0")
+	}
+	if len(out2) > 0 {
+		panic("len(out2) > 0")
+	}
+	if len(out3) > 0 {
+		panic("len(out3) > 0")
+	}
+	if outputs > 3 {
+		panic("outputs > 3")
+	}
+
+	tempMAC := hmac.New(h, chainingKey)
+	tempMAC.Write(inputKeyMaterial)
+	tempKey := tempMAC.Sum(out2)
+
+	out1MAC := hmac.New(h, tempKey)
+	out1MAC.Write([]byte{0x01})
+	out1 = out1MAC.Sum(out1)
+
+	if outputs == 1 {
+		return out1, nil, nil
+	}
+
+	out2MAC := hmac.New(h, tempKey)
+	out2MAC.Write(out1)
+	out2MAC.Write([]byte{0x02})
+	out2 = out2MAC.Sum(out2)
+
+	if outputs == 2 {
+		return out1, out2, nil
+	}
+
+	out3MAC := hmac.New(h, tempKey)
+	out3MAC.Write(out2)
+	out3MAC.Write([]byte{0x03})
+	out3 = out3MAC.Sum(out3)
+
+	return out1, out2, out3
+}

vendor/github.com/flynn/noise/patterns.go

@@ -0,0 +1,141 @@
+package noise
+
+var HandshakeNN = HandshakePattern{
+	Name: "NN",
+	Messages: [][]MessagePattern{
+		{MessagePatternE},
+		{MessagePatternE, MessagePatternDHEE},
+	},
+}
+
+var HandshakeKN = HandshakePattern{
+	Name:                 "KN",
+	InitiatorPreMessages: []MessagePattern{MessagePatternS},
+	Messages: [][]MessagePattern{
+		{MessagePatternE},
+		{MessagePatternE, MessagePatternDHEE, MessagePatternDHSE},
+	},
+}
+
+var HandshakeNK = HandshakePattern{
+	Name:                 "NK",
+	ResponderPreMessages: []MessagePattern{MessagePatternS},
+	Messages: [][]MessagePattern{
+		{MessagePatternE, MessagePatternDHES},
+		{MessagePatternE, MessagePatternDHEE},
+	},
+}
+
+var HandshakeKK = HandshakePattern{
+	Name:                 "KK",
+	InitiatorPreMessages: []MessagePattern{MessagePatternS},
+	ResponderPreMessages: []MessagePattern{MessagePatternS},
+	Messages: [][]MessagePattern{
+		{MessagePatternE, MessagePatternDHES, MessagePatternDHSS},
+		{MessagePatternE, MessagePatternDHEE, MessagePatternDHSE},
+	},
+}
+
+var HandshakeNX = HandshakePattern{
+	Name: "NX",
+	Messages: [][]MessagePattern{
+		{MessagePatternE},
+		{MessagePatternE, MessagePatternDHEE, MessagePatternS, MessagePatternDHES},
+	},
+}
+
+var HandshakeKX = HandshakePattern{
+	Name:                 "KX",
+	InitiatorPreMessages: []MessagePattern{MessagePatternS},
+	Messages: [][]MessagePattern{
+		{MessagePatternE},
+		{MessagePatternE, MessagePatternDHEE, MessagePatternDHSE, MessagePatternS, MessagePatternDHES},
+	},
+}
+
+var HandshakeXN = HandshakePattern{
+	Name: "XN",
+	Messages: [][]MessagePattern{
+		{MessagePatternE},
+		{MessagePatternE, MessagePatternDHEE},
+		{MessagePatternS, MessagePatternDHSE},
+	},
+}
+
+var HandshakeIN = HandshakePattern{
+	Name: "IN",
+	Messages: [][]MessagePattern{
+		{MessagePatternE, MessagePatternS},
+		{MessagePatternE, MessagePatternDHEE, MessagePatternDHSE},
+	},
+}
+
+var HandshakeXK = HandshakePattern{
+	Name:                 "XK",
+	ResponderPreMessages: []MessagePattern{MessagePatternS},
+	Messages: [][]MessagePattern{
+		{MessagePatternE, MessagePatternDHES},
+		{MessagePatternE, MessagePatternDHEE},
+		{MessagePatternS, MessagePatternDHSE},
+	},
+}
+
+var HandshakeIK = HandshakePattern{
+	Name:                 "IK",
+	ResponderPreMessages: []MessagePattern{MessagePatternS},
+	Messages: [][]MessagePattern{
+		{MessagePatternE, MessagePatternDHES, MessagePatternS, MessagePatternDHSS},
+		{MessagePatternE, MessagePatternDHEE, MessagePatternDHSE},
+	},
+}
+
+var HandshakeXX = HandshakePattern{
+	Name: "XX",
+	Messages: [][]MessagePattern{
+		{MessagePatternE},
+		{MessagePatternE, MessagePatternDHEE, MessagePatternS, MessagePatternDHES},
+		{MessagePatternS, MessagePatternDHSE},
+	},
+}
+
+var HandshakeXXfallback = HandshakePattern{
+	Name:                 "XXfallback",
+	ResponderPreMessages: []MessagePattern{MessagePatternE},
+	Messages: [][]MessagePattern{
+		{MessagePatternE, MessagePatternDHEE, MessagePatternS, MessagePatternDHSE},
+		{MessagePatternS, MessagePatternDHES},
+	},
+}
+
+var HandshakeIX = HandshakePattern{
+	Name: "IX",
+	Messages: [][]MessagePattern{
+		{MessagePatternE, MessagePatternS},
+		{MessagePatternE, MessagePatternDHEE, MessagePatternDHSE, MessagePatternS, MessagePatternDHES},
+	},
+}
+
+var HandshakeN = HandshakePattern{
+	Name:                 "N",
+	ResponderPreMessages: []MessagePattern{MessagePatternS},
+	Messages: [][]MessagePattern{
+		{MessagePatternE, MessagePatternDHES},
+	},
+}
+
+var HandshakeK = HandshakePattern{
+	Name:                 "K",
+	InitiatorPreMessages: []MessagePattern{MessagePatternS},
+	ResponderPreMessages: []MessagePattern{MessagePatternS},
+	Messages: [][]MessagePattern{
+		{MessagePatternE, MessagePatternDHES, MessagePatternDHSS},
+	},
+}
+
+var HandshakeX = HandshakePattern{
+	Name:                 "X",
+	ResponderPreMessages: []MessagePattern{MessagePatternS},
+	Messages: [][]MessagePattern{
+		{MessagePatternE, MessagePatternDHES, MessagePatternS, MessagePatternDHSS},
+	},
+}

vendor/github.com/flynn/noise/state.go

@@ -0,0 +1,600 @@
+// Package noise implements the Noise Protocol Framework.
+//
+// Noise is a low-level framework for building crypto protocols. Noise protocols
+// support mutual and optional authentication, identity hiding, forward secrecy,
+// zero round-trip encryption, and other advanced features. For more details,
+// visit https://noiseprotocol.org.
+package noise
+
+import (
+	"crypto/rand"
+	"errors"
+	"fmt"
+	"io"
+	"math"
+)
+
+// A CipherState provides symmetric encryption and decryption after a successful
+// handshake.
+type CipherState struct {
+	cs CipherSuite
+	c  Cipher
+	k  [32]byte
+	n  uint64
+
+	invalid bool
+}
+
+// MaxNonce is the maximum value of n that is allowed. ErrMaxNonce is returned
+// by Encrypt and Decrypt after this has been reached. 2^64-1 is reserved for rekeys.
+const MaxNonce = uint64(math.MaxUint64) - 1
+
+var ErrMaxNonce = errors.New("noise: cipherstate has reached maximum n, a new handshake must be performed")
+var ErrCipherSuiteCopied = errors.New("noise: CipherSuite has been copied, state is invalid")
+
+// Encrypt encrypts the plaintext and then appends the ciphertext and an
+// authentication tag across the ciphertext and optional authenticated data to
+// out. This method automatically increments the nonce after every call, so
+// messages must be decrypted in the same order. ErrMaxNonce is returned after
+// the maximum nonce of 2^64-2 is reached.
+func (s *CipherState) Encrypt(out, ad, plaintext []byte) ([]byte, error) {
+	if s.invalid {
+		return nil, ErrCipherSuiteCopied
+	}
+	if s.n > MaxNonce {
+		return nil, ErrMaxNonce
+	}
+	out = s.c.Encrypt(out, s.n, ad, plaintext)
+	s.n++
+	return out, nil
+}
+
+// Decrypt checks the authenticity of the ciphertext and authenticated data and
+// then decrypts and appends the plaintext to out. This method automatically
+// increments the nonce after every call, messages must be provided in the same
+// order that they were encrypted with no missing messages. ErrMaxNonce is
+// returned after the maximum nonce of 2^64-2 is reached.
+func (s *CipherState) Decrypt(out, ad, ciphertext []byte) ([]byte, error) {
+	if s.invalid {
+		return nil, ErrCipherSuiteCopied
+	}
+	if s.n > MaxNonce {
+		return nil, ErrMaxNonce
+	}
+	out, err := s.c.Decrypt(out, s.n, ad, ciphertext)
+	if err != nil {
+		return nil, err
+	}
+	s.n++
+	return out, nil
+}
+
+// Cipher returns the low-level symmetric encryption primitive. It should only
+// be used if nonces need to be managed manually, for example with a network
+// protocol that can deliver out-of-order messages. This is dangerous, users
+// must ensure that they are incrementing a nonce after every encrypt operation.
+// After calling this method, it is an error to call Encrypt/Decrypt on the
+// CipherState.
+func (s *CipherState) Cipher() Cipher {
+	s.invalid = true
+	return s.c
+}
+
+// Nonce returns the current value of n. This can be used to determine if a
+// new handshake should be performed due to approaching MaxNonce.
+func (s *CipherState) Nonce() uint64 {
+	return s.n
+}
+
+func (s *CipherState) Rekey() {
+	var zeros [32]byte
+	var out []byte
+	out = s.c.Encrypt(out, math.MaxUint64, []byte{}, zeros[:])
+	copy(s.k[:], out[:32])
+	s.c = s.cs.Cipher(s.k)
+}
+
+type symmetricState struct {
+	CipherState
+	hasK bool
+	ck   []byte
+	h    []byte
+
+	prevCK []byte
+	prevH  []byte
+}
+
+func (s *symmetricState) InitializeSymmetric(handshakeName []byte) {
+	h := s.cs.Hash()
+	if len(handshakeName) <= h.Size() {
+		s.h = make([]byte, h.Size())
+		copy(s.h, handshakeName)
+	} else {
+		h.Write(handshakeName)
+		s.h = h.Sum(nil)
+	}
+	s.ck = make([]byte, len(s.h))
+	copy(s.ck, s.h)
+}
+
+func (s *symmetricState) MixKey(dhOutput []byte) {
+	s.n = 0
+	s.hasK = true
+	var hk []byte
+	s.ck, hk, _ = hkdf(s.cs.Hash, 2, s.ck[:0], s.k[:0], nil, s.ck, dhOutput)
+	copy(s.k[:], hk)
+	s.c = s.cs.Cipher(s.k)
+}
+
+func (s *symmetricState) MixHash(data []byte) {
+	h := s.cs.Hash()
+	h.Write(s.h)
+	h.Write(data)
+	s.h = h.Sum(s.h[:0])
+}
+
+func (s *symmetricState) MixKeyAndHash(data []byte) {
+	var hk []byte
+	var temp []byte
+	s.ck, temp, hk = hkdf(s.cs.Hash, 3, s.ck[:0], temp, s.k[:0], s.ck, data)
+	s.MixHash(temp)
+	copy(s.k[:], hk)
+	s.c = s.cs.Cipher(s.k)
+	s.n = 0
+	s.hasK = true
+}
+
+func (s *symmetricState) EncryptAndHash(out, plaintext []byte) ([]byte, error) {
+	if !s.hasK {
+		s.MixHash(plaintext)
+		return append(out, plaintext...), nil
+	}
+	ciphertext, err := s.Encrypt(out, s.h, plaintext)
+	if err != nil {
+		return nil, err
+	}
+	s.MixHash(ciphertext[len(out):])
+	return ciphertext, nil
+}
+
+func (s *symmetricState) DecryptAndHash(out, data []byte) ([]byte, error) {
+	if !s.hasK {
+		s.MixHash(data)
+		return append(out, data...), nil
+	}
+	plaintext, err := s.Decrypt(out, s.h, data)
+	if err != nil {
+		return nil, err
+	}
+	s.MixHash(data)
+	return plaintext, nil
+}
+
+func (s *symmetricState) Split() (*CipherState, *CipherState) {
+	s1, s2 := &CipherState{cs: s.cs}, &CipherState{cs: s.cs}
+	hk1, hk2, _ := hkdf(s.cs.Hash, 2, s1.k[:0], s2.k[:0], nil, s.ck, nil)
+	copy(s1.k[:], hk1)
+	copy(s2.k[:], hk2)
+	s1.c = s.cs.Cipher(s1.k)
+	s2.c = s.cs.Cipher(s2.k)
+	return s1, s2
+}
+
+func (s *symmetricState) Checkpoint() {
+	if len(s.ck) > cap(s.prevCK) {
+		s.prevCK = make([]byte, len(s.ck))
+	}
+	s.prevCK = s.prevCK[:len(s.ck)]
+	copy(s.prevCK, s.ck)
+
+	if len(s.h) > cap(s.prevH) {
+		s.prevH = make([]byte, len(s.h))
+	}
+	s.prevH = s.prevH[:len(s.h)]
+	copy(s.prevH, s.h)
+}
+
+func (s *symmetricState) Rollback() {
+	s.ck = s.ck[:len(s.prevCK)]
+	copy(s.ck, s.prevCK)
+	s.h = s.h[:len(s.prevH)]
+	copy(s.h, s.prevH)
+}
+
+// A MessagePattern is a single message or operation used in a Noise handshake.
+type MessagePattern int
+
+// A HandshakePattern is a list of messages and operations that are used to
+// perform a specific Noise handshake.
+type HandshakePattern struct {
+	Name                 string
+	InitiatorPreMessages []MessagePattern
+	ResponderPreMessages []MessagePattern
+	Messages             [][]MessagePattern
+}
+
+const (
+	MessagePatternS MessagePattern = iota
+	MessagePatternE
+	MessagePatternDHEE
+	MessagePatternDHES
+	MessagePatternDHSE
+	MessagePatternDHSS
+	MessagePatternPSK
+)
+
+// MaxMsgLen is the maximum number of bytes that can be sent in a single Noise
+// message.
+const MaxMsgLen = 65535
+
+// A HandshakeState tracks the state of a Noise handshake. It may be discarded
+// after the handshake is complete.
+type HandshakeState struct {
+	ss              symmetricState
+	s               DHKey  // local static keypair
+	e               DHKey  // local ephemeral keypair
+	rs              []byte // remote party's static public key
+	re              []byte // remote party's ephemeral public key
+	psk             []byte // preshared key, maybe zero length
+	messagePatterns [][]MessagePattern
+	shouldWrite     bool
+	initiator       bool
+	msgIdx          int
+	rng             io.Reader
+}
+
+// A Config provides the details necessary to process a Noise handshake. It is
+// never modified by this package, and can be reused.
+type Config struct {
+	// CipherSuite is the set of cryptographic primitives that will be used.
+	CipherSuite CipherSuite
+
+	// Random is the source for cryptographically appropriate random bytes. If
+	// zero, it is automatically configured.
+	Random io.Reader
+
+	// Pattern is the pattern for the handshake.
+	Pattern HandshakePattern
+
+	// Initiator must be true if the first message in the handshake will be sent
+	// by this peer.
+	Initiator bool
+
+	// Prologue is an optional message that has already be communicated and must
+	// be identical on both sides for the handshake to succeed.
+	Prologue []byte
+
+	// PresharedKey is the optional preshared key for the handshake.
+	PresharedKey []byte
+
+	// PresharedKeyPlacement specifies the placement position of the PSK token
+	// when PresharedKey is specified
+	PresharedKeyPlacement int
+
+	// StaticKeypair is this peer's static keypair, required if part of the
+	// handshake.
+	StaticKeypair DHKey
+
+	// EphemeralKeypair is this peer's ephemeral keypair that was provided as
+	// a pre-message in the handshake.
+	EphemeralKeypair DHKey
+
+	// PeerStatic is the static public key of the remote peer that was provided
+	// as a pre-message in the handshake.
+	PeerStatic []byte
+
+	// PeerEphemeral is the ephemeral public key of the remote peer that was
+	// provided as a pre-message in the handshake.
+	PeerEphemeral []byte
+}
+
+// NewHandshakeState starts a new handshake using the provided configuration.
+func NewHandshakeState(c Config) (*HandshakeState, error) {
+	hs := &HandshakeState{
+		s:               c.StaticKeypair,
+		e:               c.EphemeralKeypair,
+		rs:              c.PeerStatic,
+		psk:             c.PresharedKey,
+		messagePatterns: c.Pattern.Messages,
+		shouldWrite:     c.Initiator,
+		initiator:       c.Initiator,
+		rng:             c.Random,
+	}
+	if hs.rng == nil {
+		hs.rng = rand.Reader
+	}
+	if len(c.PeerEphemeral) > 0 {
+		hs.re = make([]byte, len(c.PeerEphemeral))
+		copy(hs.re, c.PeerEphemeral)
+	}
+	hs.ss.cs = c.CipherSuite
+	pskModifier := ""
+	if len(hs.psk) > 0 {
+		if len(hs.psk) != 32 {
+			return nil, errors.New("noise: specification mandates 256-bit preshared keys")
+		}
+		pskModifier = fmt.Sprintf("psk%d", c.PresharedKeyPlacement)
+		hs.messagePatterns = append([][]MessagePattern(nil), hs.messagePatterns...)
+		if c.PresharedKeyPlacement == 0 {
+			hs.messagePatterns[0] = append([]MessagePattern{MessagePatternPSK}, hs.messagePatterns[0]...)
+		} else {
+			hs.messagePatterns[c.PresharedKeyPlacement-1] = append(hs.messagePatterns[c.PresharedKeyPlacement-1], MessagePatternPSK)
+		}
+	}
+	hs.ss.InitializeSymmetric([]byte("Noise_" + c.Pattern.Name + pskModifier + "_" + string(hs.ss.cs.Name())))
+	hs.ss.MixHash(c.Prologue)
+	for _, m := range c.Pattern.InitiatorPreMessages {
+		switch {
+		case c.Initiator && m == MessagePatternS:
+			hs.ss.MixHash(hs.s.Public)
+		case c.Initiator && m == MessagePatternE:
+			hs.ss.MixHash(hs.e.Public)
+		case !c.Initiator && m == MessagePatternS:
+			hs.ss.MixHash(hs.rs)
+		case !c.Initiator && m == MessagePatternE:
+			hs.ss.MixHash(hs.re)
+		}
+	}
+	for _, m := range c.Pattern.ResponderPreMessages {
+		switch {
+		case !c.Initiator && m == MessagePatternS:
+			hs.ss.MixHash(hs.s.Public)
+		case !c.Initiator && m == MessagePatternE:
+			hs.ss.MixHash(hs.e.Public)
+		case c.Initiator && m == MessagePatternS:
+			hs.ss.MixHash(hs.rs)
+		case c.Initiator && m == MessagePatternE:
+			hs.ss.MixHash(hs.re)
+		}
+	}
+	return hs, nil
+}
+
+// WriteMessage appends a handshake message to out. The message will include the
+// optional payload if provided. If the handshake is completed by the call, two
+// CipherStates will be returned, one is used for encryption of messages to the
+// remote peer, the other is used for decryption of messages from the remote
+// peer. It is an error to call this method out of sync with the handshake
+// pattern.
+func (s *HandshakeState) WriteMessage(out, payload []byte) ([]byte, *CipherState, *CipherState, error) {
+	if !s.shouldWrite {
+		return nil, nil, nil, errors.New("noise: unexpected call to WriteMessage should be ReadMessage")
+	}
+	if s.msgIdx > len(s.messagePatterns)-1 {
+		return nil, nil, nil, errors.New("noise: no handshake messages left")
+	}
+	if len(payload) > MaxMsgLen {
+		return nil, nil, nil, errors.New("noise: message is too long")
+	}
+
+	var err error
+	for _, msg := range s.messagePatterns[s.msgIdx] {
+		switch msg {
+		case MessagePatternE:
+			e, err := s.ss.cs.GenerateKeypair(s.rng)
+			if err != nil {
+				return nil, nil, nil, err
+			}
+			s.e = e
+			out = append(out, s.e.Public...)
+			s.ss.MixHash(s.e.Public)
+			if len(s.psk) > 0 {
+				s.ss.MixKey(s.e.Public)
+			}
+		case MessagePatternS:
+			if len(s.s.Public) == 0 {
+				return nil, nil, nil, errors.New("noise: invalid state, s.Public is nil")
+			}
+			out, err = s.ss.EncryptAndHash(out, s.s.Public)
+			if err != nil {
+				return nil, nil, nil, err
+			}
+		case MessagePatternDHEE:
+			dh, err := s.ss.cs.DH(s.e.Private, s.re)
+			if err != nil {
+				return nil, nil, nil, err
+			}
+			s.ss.MixKey(dh)
+		case MessagePatternDHES:
+			if s.initiator {
+				dh, err := s.ss.cs.DH(s.e.Private, s.rs)
+				if err != nil {
+					return nil, nil, nil, err
+				}
+				s.ss.MixKey(dh)
+			} else {
+				dh, err := s.ss.cs.DH(s.s.Private, s.re)
+				if err != nil {
+					return nil, nil, nil, err
+				}
+				s.ss.MixKey(dh)
+			}
+		case MessagePatternDHSE:
+			if s.initiator {
+				dh, err := s.ss.cs.DH(s.s.Private, s.re)
+				if err != nil {
+					return nil, nil, nil, err
+				}
+				s.ss.MixKey(dh)
+			} else {
+				dh, err := s.ss.cs.DH(s.e.Private, s.rs)
+				if err != nil {
+					return nil, nil, nil, err
+				}
+				s.ss.MixKey(dh)
+			}
+		case MessagePatternDHSS:
+			dh, err := s.ss.cs.DH(s.s.Private, s.rs)
+			if err != nil {
+				return nil, nil, nil, err
+			}
+			s.ss.MixKey(dh)
+		case MessagePatternPSK:
+			s.ss.MixKeyAndHash(s.psk)
+		}
+	}
+	s.shouldWrite = false
+	s.msgIdx++
+	out, err = s.ss.EncryptAndHash(out, payload)
+	if err != nil {
+		return nil, nil, nil, err
+	}
+
+	if s.msgIdx >= len(s.messagePatterns) {
+		cs1, cs2 := s.ss.Split()
+		return out, cs1, cs2, nil
+	}
+
+	return out, nil, nil, nil
+}
+
+// ErrShortMessage is returned by ReadMessage if a message is not as long as it should be.
+var ErrShortMessage = errors.New("noise: message is too short")
+
+// ReadMessage processes a received handshake message and appends the payload,
+// if any to out. If the handshake is completed by the call, two CipherStates
+// will be returned, one is used for encryption of messages to the remote peer,
+// the other is used for decryption of messages from the remote peer. It is an
+// error to call this method out of sync with the handshake pattern.
+func (s *HandshakeState) ReadMessage(out, message []byte) ([]byte, *CipherState, *CipherState, error) {
+	if s.shouldWrite {
+		return nil, nil, nil, errors.New("noise: unexpected call to ReadMessage should be WriteMessage")
+	}
+	if s.msgIdx > len(s.messagePatterns)-1 {
+		return nil, nil, nil, errors.New("noise: no handshake messages left")
+	}
+
+	rsSet := false
+	s.ss.Checkpoint()
+
+	var err error
+	for _, msg := range s.messagePatterns[s.msgIdx] {
+		switch msg {
+		case MessagePatternE, MessagePatternS:
+			expected := s.ss.cs.DHLen()
+			if msg == MessagePatternS && s.ss.hasK {
+				expected += 16
+			}
+			if len(message) < expected {
+				return nil, nil, nil, ErrShortMessage
+			}
+			switch msg {
+			case MessagePatternE:
+				if cap(s.re) < s.ss.cs.DHLen() {
+					s.re = make([]byte, s.ss.cs.DHLen())
+				}
+				s.re = s.re[:s.ss.cs.DHLen()]
+				copy(s.re, message)
+				s.ss.MixHash(s.re)
+				if len(s.psk) > 0 {
+					s.ss.MixKey(s.re)
+				}
+			case MessagePatternS:
+				if len(s.rs) > 0 {
+					return nil, nil, nil, errors.New("noise: invalid state, rs is not nil")
+				}
+				s.rs, err = s.ss.DecryptAndHash(s.rs[:0], message[:expected])
+				rsSet = true
+			}
+			if err != nil {
+				s.ss.Rollback()
+				if rsSet {
+					s.rs = nil
+				}
+				return nil, nil, nil, err
+			}
+			message = message[expected:]
+		case MessagePatternDHEE:
+			dh, err := s.ss.cs.DH(s.e.Private, s.re)
+			if err != nil {
+				return nil, nil, nil, err
+			}
+			s.ss.MixKey(dh)
+		case MessagePatternDHES:
+			if s.initiator {
+				dh, err := s.ss.cs.DH(s.e.Private, s.rs)
+				if err != nil {
+					return nil, nil, nil, err
+				}
+				s.ss.MixKey(dh)
+			} else {
+				dh, err := s.ss.cs.DH(s.s.Private, s.re)
+				if err != nil {
+					return nil, nil, nil, err
+				}
+				s.ss.MixKey(dh)
+			}
+		case MessagePatternDHSE:
+			if s.initiator {
+				dh, err := s.ss.cs.DH(s.s.Private, s.re)
+				if err != nil {
+					return nil, nil, nil, err
+				}
+				s.ss.MixKey(dh)
+			} else {
+				dh, err := s.ss.cs.DH(s.e.Private, s.rs)
+				if err != nil {
+					return nil, nil, nil, err
+				}
+				s.ss.MixKey(dh)
+			}
+		case MessagePatternDHSS:
+			dh, err := s.ss.cs.DH(s.s.Private, s.rs)
+			if err != nil {
+				return nil, nil, nil, err
+			}
+			s.ss.MixKey(dh)
+		case MessagePatternPSK:
+			s.ss.MixKeyAndHash(s.psk)
+		}
+	}
+	out, err = s.ss.DecryptAndHash(out, message)
+	if err != nil {
+		s.ss.Rollback()
+		if rsSet {
+			s.rs = nil
+		}
+		return nil, nil, nil, err
+	}
+	s.shouldWrite = true
+	s.msgIdx++
+
+	if s.msgIdx >= len(s.messagePatterns) {
+		cs1, cs2 := s.ss.Split()
+		return out, cs1, cs2, nil
+	}
+
+	return out, nil, nil, nil
+}
+
+// ChannelBinding provides a value that uniquely identifies the session and can
+// be used as a channel binding. It is an error to call this method before the
+// handshake is complete.
+func (s *HandshakeState) ChannelBinding() []byte {
+	return s.ss.h
+}
+
+// PeerStatic returns the static key provided by the remote peer during
+// a handshake. It is an error to call this method if a handshake message
+// containing a static key has not been read.
+func (s *HandshakeState) PeerStatic() []byte {
+	return s.rs
+}
+
+// MessageIndex returns the current handshake message id
+func (s *HandshakeState) MessageIndex() int {
+	return s.msgIdx
+}
+
+// PeerEphemeral returns the ephemeral key provided by the remote peer during
+// a handshake. It is an error to call this method if a handshake message
+// containing a static key has not been read.
+func (s *HandshakeState) PeerEphemeral() []byte {
+	return s.re
+}
+
+// LocalEphemeral returns the local ephemeral key pair generated during
+// a handshake.
+func (s *HandshakeState) LocalEphemeral() DHKey {
+	return s.e
+}

vendor/github.com/gobwas/glob/.gitignore

@@ -0,0 +1,8 @@
+glob.iml
+.idea
+*.cpu
+*.mem
+*.test
+*.dot
+*.png
+*.svg

vendor/github.com/gobwas/glob/.travis.yml

@@ -0,0 +1,9 @@
+sudo: false
+
+language: go
+
+go:
+  - 1.5.3
+
+script:
+  - go test -v ./...

vendor/github.com/gobwas/glob/LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2016 Sergey Kamardin
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

vendor/github.com/gobwas/glob/bench.sh

@@ -0,0 +1,26 @@
+#! /bin/bash
+
+bench() {
+    filename="/tmp/$1-$2.bench"
+    if test -e "${filename}";
+    then
+        echo "Already exists ${filename}"
+    else
+        backup=`git rev-parse --abbrev-ref HEAD`
+        git checkout $1
+        echo -n "Creating ${filename}... "
+        go test ./... -run=NONE -bench=$2 > "${filename}" -benchmem
+        echo "OK"
+        git checkout ${backup}
+        sleep 5
+    fi
+}
+
+
+to=$1
+current=`git rev-parse --abbrev-ref HEAD`
+
+bench ${to} $2
+bench ${current} $2
+
+benchcmp $3 "/tmp/${to}-$2.bench" "/tmp/${current}-$2.bench"

vendor/github.com/gobwas/glob/compiler/compiler.go

@@ -0,0 +1,525 @@
+package compiler
+
+// TODO use constructor with all matchers, and to their structs private
+// TODO glue multiple Text nodes (like after QuoteMeta)
+
+import (
+	"fmt"
+	"reflect"
+
+	"github.com/gobwas/glob/match"
+	"github.com/gobwas/glob/syntax/ast"
+	"github.com/gobwas/glob/util/runes"
+)
+
+func optimizeMatcher(matcher match.Matcher) match.Matcher {
+	switch m := matcher.(type) {
+
+	case match.Any:
+		if len(m.Separators) == 0 {
+			return match.NewSuper()
+		}
+
+	case match.AnyOf:
+		if len(m.Matchers) == 1 {
+			return m.Matchers[0]
+		}
+
+		return m
+
+	case match.List:
+		if m.Not == false && len(m.List) == 1 {
+			return match.NewText(string(m.List))
+		}
+
+		return m
+
+	case match.BTree:
+		m.Left = optimizeMatcher(m.Left)
+		m.Right = optimizeMatcher(m.Right)
+
+		r, ok := m.Value.(match.Text)
+		if !ok {
+			return m
+		}
+
+		var (
+			leftNil  = m.Left == nil
+			rightNil = m.Right == nil
+		)
+		if leftNil && rightNil {
+			return match.NewText(r.Str)
+		}
+
+		_, leftSuper := m.Left.(match.Super)
+		lp, leftPrefix := m.Left.(match.Prefix)
+		la, leftAny := m.Left.(match.Any)
+
+		_, rightSuper := m.Right.(match.Super)
+		rs, rightSuffix := m.Right.(match.Suffix)
+		ra, rightAny := m.Right.(match.Any)
+
+		switch {
+		case leftSuper && rightSuper:
+			return match.NewContains(r.Str, false)
+
+		case leftSuper && rightNil:
+			return match.NewSuffix(r.Str)
+
+		case rightSuper && leftNil:
+			return match.NewPrefix(r.Str)
+
+		case leftNil && rightSuffix:
+			return match.NewPrefixSuffix(r.Str, rs.Suffix)
+
+		case rightNil && leftPrefix:
+			return match.NewPrefixSuffix(lp.Prefix, r.Str)
+
+		case rightNil && leftAny:
+			return match.NewSuffixAny(r.Str, la.Separators)
+
+		case leftNil && rightAny:
+			return match.NewPrefixAny(r.Str, ra.Separators)
+		}
+
+		return m
+	}
+
+	return matcher
+}
+
+func compileMatchers(matchers []match.Matcher) (match.Matcher, error) {
+	if len(matchers) == 0 {
+		return nil, fmt.Errorf("compile error: need at least one matcher")
+	}
+	if len(matchers) == 1 {
+		return matchers[0], nil
+	}
+	if m := glueMatchers(matchers); m != nil {
+		return m, nil
+	}
+
+	idx := -1
+	maxLen := -1
+	var val match.Matcher
+	for i, matcher := range matchers {
+		if l := matcher.Len(); l != -1 && l >= maxLen {
+			maxLen = l
+			idx = i
+			val = matcher
+		}
+	}
+
+	if val == nil { // not found matcher with static length
+		r, err := compileMatchers(matchers[1:])
+		if err != nil {
+			return nil, err
+		}
+		return match.NewBTree(matchers[0], nil, r), nil
+	}
+
+	left := matchers[:idx]
+	var right []match.Matcher
+	if len(matchers) > idx+1 {
+		right = matchers[idx+1:]
+	}
+
+	var l, r match.Matcher
+	var err error
+	if len(left) > 0 {
+		l, err = compileMatchers(left)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if len(right) > 0 {
+		r, err = compileMatchers(right)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return match.NewBTree(val, l, r), nil
+}
+
+func glueMatchers(matchers []match.Matcher) match.Matcher {
+	if m := glueMatchersAsEvery(matchers); m != nil {
+		return m
+	}
+	if m := glueMatchersAsRow(matchers); m != nil {
+		return m
+	}
+	return nil
+}
+
+func glueMatchersAsRow(matchers []match.Matcher) match.Matcher {
+	if len(matchers) <= 1 {
+		return nil
+	}
+
+	var (
+		c []match.Matcher
+		l int
+	)
+	for _, matcher := range matchers {
+		if ml := matcher.Len(); ml == -1 {
+			return nil
+		} else {
+			c = append(c, matcher)
+			l += ml
+		}
+	}
+	return match.NewRow(l, c...)
+}
+
+func glueMatchersAsEvery(matchers []match.Matcher) match.Matcher {
+	if len(matchers) <= 1 {
+		return nil
+	}
+
+	var (
+		hasAny    bool
+		hasSuper  bool
+		hasSingle bool
+		min       int
+		separator []rune
+	)
+
+	for i, matcher := range matchers {
+		var sep []rune
+
+		switch m := matcher.(type) {
+		case match.Super:
+			sep = []rune{}
+			hasSuper = true
+
+		case match.Any:
+			sep = m.Separators
+			hasAny = true
+
+		case match.Single:
+			sep = m.Separators
+			hasSingle = true
+			min++
+
+		case match.List:
+			if !m.Not {
+				return nil
+			}
+			sep = m.List
+			hasSingle = true
+			min++
+
+		default:
+			return nil
+		}
+
+		// initialize
+		if i == 0 {
+			separator = sep
+		}
+
+		if runes.Equal(sep, separator) {
+			continue
+		}
+
+		return nil
+	}
+
+	if hasSuper && !hasAny && !hasSingle {
+		return match.NewSuper()
+	}
+
+	if hasAny && !hasSuper && !hasSingle {
+		return match.NewAny(separator)
+	}
+
+	if (hasAny || hasSuper) && min > 0 && len(separator) == 0 {
+		return match.NewMin(min)
+	}
+
+	every := match.NewEveryOf()
+
+	if min > 0 {
+		every.Add(match.NewMin(min))
+
+		if !hasAny && !hasSuper {
+			every.Add(match.NewMax(min))
+		}
+	}
+
+	if len(separator) > 0 {
+		every.Add(match.NewContains(string(separator), true))
+	}
+
+	return every
+}
+
+func minimizeMatchers(matchers []match.Matcher) []match.Matcher {
+	var done match.Matcher
+	var left, right, count int
+
+	for l := 0; l < len(matchers); l++ {
+		for r := len(matchers); r > l; r-- {
+			if glued := glueMatchers(matchers[l:r]); glued != nil {
+				var swap bool
+
+				if done == nil {
+					swap = true
+				} else {
+					cl, gl := done.Len(), glued.Len()
+					swap = cl > -1 && gl > -1 && gl > cl
+					swap = swap || count < r-l
+				}
+
+				if swap {
+					done = glued
+					left = l
+					right = r
+					count = r - l
+				}
+			}
+		}
+	}
+
+	if done == nil {
+		return matchers
+	}
+
+	next := append(append([]match.Matcher{}, matchers[:left]...), done)
+	if right < len(matchers) {
+		next = append(next, matchers[right:]...)
+	}
+
+	if len(next) == len(matchers) {
+		return next
+	}
+
+	return minimizeMatchers(next)
+}
+
+// minimizeAnyOf tries to apply some heuristics to minimize number of nodes in given tree
+func minimizeTree(tree *ast.Node) *ast.Node {
+	switch tree.Kind {
+	case ast.KindAnyOf:
+		return minimizeTreeAnyOf(tree)
+	default:
+		return nil
+	}
+}
+
+// minimizeAnyOf tries to find common children of given node of AnyOf pattern
+// it searches for common children from left and from right
+// if any common children are found – then it returns new optimized ast tree
+// else it returns nil
+func minimizeTreeAnyOf(tree *ast.Node) *ast.Node {
+	if !areOfSameKind(tree.Children, ast.KindPattern) {
+		return nil
+	}
+
+	commonLeft, commonRight := commonChildren(tree.Children)
+	commonLeftCount, commonRightCount := len(commonLeft), len(commonRight)
+	if commonLeftCount == 0 && commonRightCount == 0 { // there are no common parts
+		return nil
+	}
+
+	var result []*ast.Node
+	if commonLeftCount > 0 {
+		result = append(result, ast.NewNode(ast.KindPattern, nil, commonLeft...))
+	}
+
+	var anyOf []*ast.Node
+	for _, child := range tree.Children {
+		reuse := child.Children[commonLeftCount : len(child.Children)-commonRightCount]
+		var node *ast.Node
+		if len(reuse) == 0 {
+			// this pattern is completely reduced by commonLeft and commonRight patterns
+			// so it become nothing
+			node = ast.NewNode(ast.KindNothing, nil)
+		} else {
+			node = ast.NewNode(ast.KindPattern, nil, reuse...)
+		}
+		anyOf = appendIfUnique(anyOf, node)
+	}
+	switch {
+	case len(anyOf) == 1 && anyOf[0].Kind != ast.KindNothing:
+		result = append(result, anyOf[0])
+	case len(anyOf) > 1:
+		result = append(result, ast.NewNode(ast.KindAnyOf, nil, anyOf...))
+	}
+
+	if commonRightCount > 0 {
+		result = append(result, ast.NewNode(ast.KindPattern, nil, commonRight...))
+	}
+
+	return ast.NewNode(ast.KindPattern, nil, result...)
+}
+
+func commonChildren(nodes []*ast.Node) (commonLeft, commonRight []*ast.Node) {
+	if len(nodes) <= 1 {
+		return
+	}
+
+	// find node that has least number of children
+	idx := leastChildren(nodes)
+	if idx == -1 {
+		return
+	}
+	tree := nodes[idx]
+	treeLength := len(tree.Children)
+
+	// allocate max able size for rightCommon slice
+	// to get ability insert elements in reverse order (from end to start)
+	// without sorting
+	commonRight = make([]*ast.Node, treeLength)
+	lastRight := treeLength // will use this to get results as commonRight[lastRight:]
+
+	var (
+		breakLeft   bool
+		breakRight  bool
+		commonTotal int
+	)
+	for i, j := 0, treeLength-1; commonTotal < treeLength && j >= 0 && !(breakLeft && breakRight); i, j = i+1, j-1 {
+		treeLeft := tree.Children[i]
+		treeRight := tree.Children[j]
+
+		for k := 0; k < len(nodes) && !(breakLeft && breakRight); k++ {
+			// skip least children node
+			if k == idx {
+				continue
+			}
+
+			restLeft := nodes[k].Children[i]
+			restRight := nodes[k].Children[j+len(nodes[k].Children)-treeLength]
+
+			breakLeft = breakLeft || !treeLeft.Equal(restLeft)
+
+			// disable searching for right common parts, if left part is already overlapping
+			breakRight = breakRight || (!breakLeft && j <= i)
+			breakRight = breakRight || !treeRight.Equal(restRight)
+		}
+
+		if !breakLeft {
+			commonTotal++
+			commonLeft = append(commonLeft, treeLeft)
+		}
+		if !breakRight {
+			commonTotal++
+			lastRight = j
+			commonRight[j] = treeRight
+		}
+	}
+
+	commonRight = commonRight[lastRight:]
+
+	return
+}
+
+func appendIfUnique(target []*ast.Node, val *ast.Node) []*ast.Node {
+	for _, n := range target {
+		if reflect.DeepEqual(n, val) {
+			return target
+		}
+	}
+	return append(target, val)
+}
+
+func areOfSameKind(nodes []*ast.Node, kind ast.Kind) bool {
+	for _, n := range nodes {
+		if n.Kind != kind {
+			return false
+		}
+	}
+	return true
+}
+
+func leastChildren(nodes []*ast.Node) int {
+	min := -1
+	idx := -1
+	for i, n := range nodes {
+		if idx == -1 || (len(n.Children) < min) {
+			min = len(n.Children)
+			idx = i
+		}
+	}
+	return idx
+}
+
+func compileTreeChildren(tree *ast.Node, sep []rune) ([]match.Matcher, error) {
+	var matchers []match.Matcher
+	for _, desc := range tree.Children {
+		m, err := compile(desc, sep)
+		if err != nil {
+			return nil, err
+		}
+		matchers = append(matchers, optimizeMatcher(m))
+	}
+	return matchers, nil
+}
+
+func compile(tree *ast.Node, sep []rune) (m match.Matcher, err error) {
+	switch tree.Kind {
+	case ast.KindAnyOf:
+		// todo this could be faster on pattern_alternatives_combine_lite (see glob_test.go)
+		if n := minimizeTree(tree); n != nil {
+			return compile(n, sep)
+		}
+		matchers, err := compileTreeChildren(tree, sep)
+		if err != nil {
+			return nil, err
+		}
+		return match.NewAnyOf(matchers...), nil
+
+	case ast.KindPattern:
+		if len(tree.Children) == 0 {
+			return match.NewNothing(), nil
+		}
+		matchers, err := compileTreeChildren(tree, sep)
+		if err != nil {
+			return nil, err
+		}
+		m, err = compileMatchers(minimizeMatchers(matchers))
+		if err != nil {
+			return nil, err
+		}
+
+	case ast.KindAny:
+		m = match.NewAny(sep)
+
+	case ast.KindSuper:
+		m = match.NewSuper()
+
+	case ast.KindSingle:
+		m = match.NewSingle(sep)
+
+	case ast.KindNothing:
+		m = match.NewNothing()
+
+	case ast.KindList:
+		l := tree.Value.(ast.List)
+		m = match.NewList([]rune(l.Chars), l.Not)
+
+	case ast.KindRange:
+		r := tree.Value.(ast.Range)
+		m = match.NewRange(r.Lo, r.Hi, r.Not)
+
+	case ast.KindText:
+		t := tree.Value.(ast.Text)
+		m = match.NewText(t.Text)
+
+	default:
+		return nil, fmt.Errorf("could not compile tree: unknown node type")
+	}
+
+	return optimizeMatcher(m), nil
+}
+
+func Compile(tree *ast.Node, sep []rune) (match.Matcher, error) {
+	m, err := compile(tree, sep)
+	if err != nil {
+		return nil, err
+	}
+
+	return m, nil
+}

vendor/github.com/gobwas/glob/glob.go

@@ -0,0 +1,80 @@
+package glob
+
+import (
+	"github.com/gobwas/glob/compiler"
+	"github.com/gobwas/glob/syntax"
+)
+
+// Glob represents compiled glob pattern.
+type Glob interface {
+	Match(string) bool
+}
+
+// Compile creates Glob for given pattern and strings (if any present after pattern) as separators.
+// The pattern syntax is:
+//
+//    pattern:
+//        { term }
+//
+//    term:
+//        `*`         matches any sequence of non-separator characters
+//        `**`        matches any sequence of characters
+//        `?`         matches any single non-separator character
+//        `[` [ `!` ] { character-range } `]`
+//                    character class (must be non-empty)
+//        `{` pattern-list `}`
+//                    pattern alternatives
+//        c           matches character c (c != `*`, `**`, `?`, `\`, `[`, `{`, `}`)
+//        `\` c       matches character c
+//
+//    character-range:
+//        c           matches character c (c != `\\`, `-`, `]`)
+//        `\` c       matches character c
+//        lo `-` hi   matches character c for lo <= c <= hi
+//
+//    pattern-list:
+//        pattern { `,` pattern }
+//                    comma-separated (without spaces) patterns
+//
+func Compile(pattern string, separators ...rune) (Glob, error) {
+	ast, err := syntax.Parse(pattern)
+	if err != nil {
+		return nil, err
+	}
+
+	matcher, err := compiler.Compile(ast, separators)
+	if err != nil {
+		return nil, err
+	}
+
+	return matcher, nil
+}
+
+// MustCompile is the same as Compile, except that if Compile returns error, this will panic
+func MustCompile(pattern string, separators ...rune) Glob {
+	g, err := Compile(pattern, separators...)
+	if err != nil {
+		panic(err)
+	}
+
+	return g
+}
+
+// QuoteMeta returns a string that quotes all glob pattern meta characters
+// inside the argument text; For example, QuoteMeta(`{foo*}`) returns `\[foo\*\]`.
+func QuoteMeta(s string) string {
+	b := make([]byte, 2*len(s))
+
+	// a byte loop is correct because all meta characters are ASCII
+	j := 0
+	for i := 0; i < len(s); i++ {
+		if syntax.Special(s[i]) {
+			b[j] = '\\'
+			j++
+		}
+		b[j] = s[i]
+		j++
+	}
+
+	return string(b[0:j])
+}

vendor/github.com/gobwas/glob/match/any.go

@@ -0,0 +1,45 @@
+package match
+
+import (
+	"fmt"
+	"github.com/gobwas/glob/util/strings"
+)
+
+type Any struct {
+	Separators []rune
+}
+
+func NewAny(s []rune) Any {
+	return Any{s}
+}
+
+func (self Any) Match(s string) bool {
+	return strings.IndexAnyRunes(s, self.Separators) == -1
+}
+
+func (self Any) Index(s string) (int, []int) {
+	found := strings.IndexAnyRunes(s, self.Separators)
+	switch found {
+	case -1:
+	case 0:
+		return 0, segments0
+	default:
+		s = s[:found]
+	}
+
+	segments := acquireSegments(len(s))
+	for i := range s {
+		segments = append(segments, i)
+	}
+	segments = append(segments, len(s))
+
+	return 0, segments
+}
+
+func (self Any) Len() int {
+	return lenNo
+}
+
+func (self Any) String() string {
+	return fmt.Sprintf("<any:![%s]>", string(self.Separators))
+}

vendor/github.com/gobwas/glob/match/any_of.go

@@ -0,0 +1,82 @@
+package match
+
+import "fmt"
+
+type AnyOf struct {
+	Matchers Matchers
+}
+
+func NewAnyOf(m ...Matcher) AnyOf {
+	return AnyOf{Matchers(m)}
+}
+
+func (self *AnyOf) Add(m Matcher) error {
+	self.Matchers = append(self.Matchers, m)
+	return nil
+}
+
+func (self AnyOf) Match(s string) bool {
+	for _, m := range self.Matchers {
+		if m.Match(s) {
+			return true
+		}
+	}
+
+	return false
+}
+
+func (self AnyOf) Index(s string) (int, []int) {
+	index := -1
+
+	segments := acquireSegments(len(s))
+	for _, m := range self.Matchers {
+		idx, seg := m.Index(s)
+		if idx == -1 {
+			continue
+		}
+
+		if index == -1 || idx < index {
+			index = idx
+			segments = append(segments[:0], seg...)
+			continue
+		}
+
+		if idx > index {
+			continue
+		}
+
+		// here idx == index
+		segments = appendMerge(segments, seg)
+	}
+
+	if index == -1 {
+		releaseSegments(segments)
+		return -1, nil
+	}
+
+	return index, segments
+}
+
+func (self AnyOf) Len() (l int) {
+	l = -1
+	for _, m := range self.Matchers {
+		ml := m.Len()
+		switch {
+		case l == -1:
+			l = ml
+			continue
+
+		case ml == -1:
+			return -1
+
+		case l != ml:
+			return -1
+		}
+	}
+
+	return
+}
+
+func (self AnyOf) String() string {
+	return fmt.Sprintf("<any_of:[%s]>", self.Matchers)
+}

vendor/github.com/gobwas/glob/match/btree.go

@@ -0,0 +1,146 @@
+package match
+
+import (
+	"fmt"
+	"unicode/utf8"
+)
+
+type BTree struct {
+	Value            Matcher
+	Left             Matcher
+	Right            Matcher
+	ValueLengthRunes int
+	LeftLengthRunes  int
+	RightLengthRunes int
+	LengthRunes      int
+}
+
+func NewBTree(Value, Left, Right Matcher) (tree BTree) {
+	tree.Value = Value
+	tree.Left = Left
+	tree.Right = Right
+
+	lenOk := true
+	if tree.ValueLengthRunes = Value.Len(); tree.ValueLengthRunes == -1 {
+		lenOk = false
+	}
+
+	if Left != nil {
+		if tree.LeftLengthRunes = Left.Len(); tree.LeftLengthRunes == -1 {
+			lenOk = false
+		}
+	}
+
+	if Right != nil {
+		if tree.RightLengthRunes = Right.Len(); tree.RightLengthRunes == -1 {
+			lenOk = false
+		}
+	}
+
+	if lenOk {
+		tree.LengthRunes = tree.LeftLengthRunes + tree.ValueLengthRunes + tree.RightLengthRunes
+	} else {
+		tree.LengthRunes = -1
+	}
+
+	return tree
+}
+
+func (self BTree) Len() int {
+	return self.LengthRunes
+}
+
+// todo?
+func (self BTree) Index(s string) (int, []int) {
+	return -1, nil
+}
+
+func (self BTree) Match(s string) bool {
+	inputLen := len(s)
+
+	// self.Length, self.RLen and self.LLen are values meaning the length of runes for each part
+	// here we manipulating byte length for better optimizations
+	// but these checks still works, cause minLen of 1-rune string is 1 byte.
+	if self.LengthRunes != -1 && self.LengthRunes > inputLen {
+		return false
+	}
+
+	// try to cut unnecessary parts
+	// by knowledge of length of right and left part
+	var offset, limit int
+	if self.LeftLengthRunes >= 0 {
+		offset = self.LeftLengthRunes
+	}
+	if self.RightLengthRunes >= 0 {
+		limit = inputLen - self.RightLengthRunes
+	} else {
+		limit = inputLen
+	}
+
+	for offset < limit {
+		// search for matching part in substring
+		index, segments := self.Value.Index(s[offset:limit])
+		if index == -1 {
+			releaseSegments(segments)
+			return false
+		}
+
+		l := s[:offset+index]
+		var left bool
+		if self.Left != nil {
+			left = self.Left.Match(l)
+		} else {
+			left = l == ""
+		}
+
+		if left {
+			for i := len(segments) - 1; i >= 0; i-- {
+				length := segments[i]
+
+				var right bool
+				var r string
+				// if there is no string for the right branch
+				if inputLen <= offset+index+length {
+					r = ""
+				} else {
+					r = s[offset+index+length:]
+				}
+
+				if self.Right != nil {
+					right = self.Right.Match(r)
+				} else {
+					right = r == ""
+				}
+
+				if right {
+					releaseSegments(segments)
+					return true
+				}
+			}
+		}
+
+		_, step := utf8.DecodeRuneInString(s[offset+index:])
+		offset += index + step
+
+		releaseSegments(segments)
+	}
+
+	return false
+}
+
+func (self BTree) String() string {
+	const n string = "<nil>"
+	var l, r string
+	if self.Left == nil {
+		l = n
+	} else {
+		l = self.Left.String()
+	}
+	if self.Right == nil {
+		r = n
+	} else {
+		r = self.Right.String()
+	}
+
+	return fmt.Sprintf("<btree:[%s<-%s->%s]>", l, self.Value, r)
+}

vendor/github.com/gobwas/glob/match/contains.go

@@ -0,0 +1,58 @@
+package match
+
+import (
+	"fmt"
+	"strings"
+)
+
+type Contains struct {
+	Needle string
+	Not    bool
+}
+
+func NewContains(needle string, not bool) Contains {
+	return Contains{needle, not}
+}
+
+func (self Contains) Match(s string) bool {
+	return strings.Contains(s, self.Needle) != self.Not
+}
+
+func (self Contains) Index(s string) (int, []int) {
+	var offset int
+
+	idx := strings.Index(s, self.Needle)
+
+	if !self.Not {
+		if idx == -1 {
+			return -1, nil
+		}
+
+		offset = idx + len(self.Needle)
+		if len(s) <= offset {
+			return 0, []int{offset}
+		}
+		s = s[offset:]
+	} else if idx != -1 {
+		s = s[:idx]
+	}
+
+	segments := acquireSegments(len(s) + 1)
+	for i := range s {
+		segments = append(segments, offset+i)
+	}
+
+	return 0, append(segments, offset+len(s))
+}
+
+func (self Contains) Len() int {
+	return lenNo
+}
+
+func (self Contains) String() string {
+	var not string
+	if self.Not {
+		not = "!"
+	}
+	return fmt.Sprintf("<contains:%s[%s]>", not, self.Needle)
+}