forgejo-federation/modules/markdown/markdown.go
2017-07-06 16:38:38 -04:00

709 lines
21 KiB
Go

// Copyright 2014 The Gogs Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package markdown
import (
"bytes"
"fmt"
"io"
"net/url"
"path"
"path/filepath"
"regexp"
"strings"
"code.gitea.io/gitea/modules/base"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/markup"
"code.gitea.io/gitea/modules/setting"
"github.com/Unknwon/com"
"github.com/russross/blackfriday"
"golang.org/x/net/html"
)
// Issue name styles
const (
IssueNameStyleNumeric = "numeric"
IssueNameStyleAlphanumeric = "alphanumeric"
)
// IsMarkdownFile reports whether name looks like a Markdown file
// based on its extension.
func IsMarkdownFile(name string) bool {
extension := strings.ToLower(filepath.Ext(name))
for _, ext := range setting.Markdown.FileExtensions {
if strings.ToLower(ext) == extension {
return true
}
}
return false
}
var (
// MentionPattern matches string that mentions someone, e.g. @Unknwon
MentionPattern = regexp.MustCompile(`(\s|^|\W)@[0-9a-zA-Z-_\.]+`)
// IssueNumericPattern matches string that references to a numeric issue, e.g. #1287
IssueNumericPattern = regexp.MustCompile(`( |^|\()#[0-9]+\b`)
// IssueAlphanumericPattern matches string that references to an alphanumeric issue, e.g. ABC-1234
IssueAlphanumericPattern = regexp.MustCompile(`( |^|\()[A-Z]{1,10}-[1-9][0-9]*\b`)
// CrossReferenceIssueNumericPattern matches string that references a numeric issue in a different repository
// e.g. gogits/gogs#12345
CrossReferenceIssueNumericPattern = regexp.MustCompile(`( |^)[0-9a-zA-Z]+/[0-9a-zA-Z]+#[0-9]+\b`)
// Sha1CurrentPattern matches string that represents a commit SHA, e.g. d8a994ef243349f321568f9e36d5c3f444b99cae
// FIXME: this pattern matches pure numbers as well, right now we do a hack to check in renderSha1CurrentPattern
// by converting string to a number.
Sha1CurrentPattern = regexp.MustCompile(`(?:^|\s|\()([0-9a-f]{40})\b`)
// ShortLinkPattern matches short but difficult to parse [[name|link|arg=test]] syntax
ShortLinkPattern = regexp.MustCompile(`(\[\[.*\]\]\w*)`)
// AnySHA1Pattern allows to split url containing SHA into parts
AnySHA1Pattern = regexp.MustCompile(`(http\S*)://(\S+)/(\S+)/(\S+)/(\S+)/([0-9a-f]{40})(?:/?([^#\s]+)?(?:#(\S+))?)?`)
// IssueFullPattern allows to split issue (and pull) URLs into parts
IssueFullPattern = regexp.MustCompile(`(?:^|\s|\()(http\S*)://((?:[^\s/]+/)+)((?:\w{1,10}-)?[1-9][0-9]*)([\?|#]\S+.(\S+)?)?\b`)
validLinksPattern = regexp.MustCompile(`^[a-z][\w-]+://`)
)
// isLink reports whether link fits valid format.
func isLink(link []byte) bool {
return validLinksPattern.Match(link)
}
// FindAllMentions matches mention patterns in given content
// and returns a list of found user names without @ prefix.
func FindAllMentions(content string) []string {
mentions := MentionPattern.FindAllString(content, -1)
for i := range mentions {
mentions[i] = mentions[i][strings.Index(mentions[i], "@")+1:] // Strip @ character
}
return mentions
}
// Renderer is a extended version of underlying render object.
type Renderer struct {
blackfriday.Renderer
urlPrefix string
isWikiMarkdown bool
}
// Link defines how formal links should be processed to produce corresponding HTML elements.
func (r *Renderer) Link(out *bytes.Buffer, link []byte, title []byte, content []byte) {
if len(link) > 0 && !isLink(link) {
if link[0] != '#' {
lnk := string(link)
if r.isWikiMarkdown {
lnk = URLJoin("wiki", lnk)
}
mLink := URLJoin(r.urlPrefix, lnk)
link = []byte(mLink)
}
}
r.Renderer.Link(out, link, title, content)
}
// List renders markdown bullet or digit lists to HTML
func (r *Renderer) List(out *bytes.Buffer, text func() bool, flags int) {
marker := out.Len()
if out.Len() > 0 {
out.WriteByte('\n')
}
if flags&blackfriday.LIST_TYPE_DEFINITION != 0 {
out.WriteString("<dl>")
} else if flags&blackfriday.LIST_TYPE_ORDERED != 0 {
out.WriteString("<ol class='ui list'>")
} else {
out.WriteString("<ul class='ui list'>")
}
if !text() {
out.Truncate(marker)
return
}
if flags&blackfriday.LIST_TYPE_DEFINITION != 0 {
out.WriteString("</dl>\n")
} else if flags&blackfriday.LIST_TYPE_ORDERED != 0 {
out.WriteString("</ol>\n")
} else {
out.WriteString("</ul>\n")
}
}
// ListItem defines how list items should be processed to produce corresponding HTML elements.
func (r *Renderer) ListItem(out *bytes.Buffer, text []byte, flags int) {
// Detect procedures to draw checkboxes.
prefix := ""
if bytes.HasPrefix(text, []byte("<p>")) {
prefix = "<p>"
}
switch {
case bytes.HasPrefix(text, []byte(prefix+"[ ] ")):
text = append([]byte(`<span class="ui fitted disabled checkbox"><input type="checkbox" disabled="disabled" /><label /></span>`), text[3+len(prefix):]...)
if prefix != "" {
text = bytes.Replace(text, []byte(prefix), []byte{}, 1)
}
case bytes.HasPrefix(text, []byte(prefix+"[x] ")):
text = append([]byte(`<span class="ui checked fitted disabled checkbox"><input type="checkbox" checked="" disabled="disabled" /><label /></span>`), text[3+len(prefix):]...)
if prefix != "" {
text = bytes.Replace(text, []byte(prefix), []byte{}, 1)
}
}
r.Renderer.ListItem(out, text, flags)
}
// Note: this section is for purpose of increase performance and
// reduce memory allocation at runtime since they are constant literals.
var (
svgSuffix = []byte(".svg")
svgSuffixWithMark = []byte(".svg?")
)
// Image defines how images should be processed to produce corresponding HTML elements.
func (r *Renderer) Image(out *bytes.Buffer, link []byte, title []byte, alt []byte) {
prefix := r.urlPrefix
if r.isWikiMarkdown {
prefix = URLJoin(prefix, "wiki", "src")
}
prefix = strings.Replace(prefix, "/src/", "/raw/", 1)
if len(link) > 0 {
if isLink(link) {
// External link with .svg suffix usually means CI status.
// TODO: define a keyword to allow non-svg images render as external link.
if bytes.HasSuffix(link, svgSuffix) || bytes.Contains(link, svgSuffixWithMark) {
r.Renderer.Image(out, link, title, alt)
return
}
} else {
lnk := string(link)
lnk = URLJoin(prefix, lnk)
lnk = strings.Replace(lnk, " ", "+", -1)
link = []byte(lnk)
}
}
out.WriteString(`<a href="`)
out.Write(link)
out.WriteString(`">`)
r.Renderer.Image(out, link, title, alt)
out.WriteString("</a>")
}
// cutoutVerbosePrefix cutouts URL prefix including sub-path to
// return a clean unified string of request URL path.
func cutoutVerbosePrefix(prefix string) string {
if len(prefix) == 0 || prefix[0] != '/' {
return prefix
}
count := 0
for i := 0; i < len(prefix); i++ {
if prefix[i] == '/' {
count++
}
if count >= 3+setting.AppSubURLDepth {
return prefix[:i]
}
}
return prefix
}
// URLJoin joins url components, like path.Join, but preserving contents
func URLJoin(base string, elems ...string) string {
u, err := url.Parse(base)
if err != nil {
log.Error(4, "URLJoin: Invalid base URL %s", base)
return ""
}
joinArgs := make([]string, 0, len(elems)+1)
joinArgs = append(joinArgs, u.Path)
joinArgs = append(joinArgs, elems...)
u.Path = path.Join(joinArgs...)
return u.String()
}
// RenderIssueIndexPattern renders issue indexes to corresponding links.
func RenderIssueIndexPattern(rawBytes []byte, urlPrefix string, metas map[string]string) []byte {
urlPrefix = cutoutVerbosePrefix(urlPrefix)
pattern := IssueNumericPattern
if metas["style"] == IssueNameStyleAlphanumeric {
pattern = IssueAlphanumericPattern
}
ms := pattern.FindAll(rawBytes, -1)
for _, m := range ms {
if m[0] == ' ' || m[0] == '(' {
m = m[1:] // ignore leading space or opening parentheses
}
var link string
if metas == nil {
link = fmt.Sprintf(`<a href="%s">%s</a>`, URLJoin(urlPrefix, "issues", string(m[1:])), m)
} else {
// Support for external issue tracker
if metas["style"] == IssueNameStyleAlphanumeric {
metas["index"] = string(m)
} else {
metas["index"] = string(m[1:])
}
link = fmt.Sprintf(`<a href="%s">%s</a>`, com.Expand(metas["format"], metas), m)
}
rawBytes = bytes.Replace(rawBytes, m, []byte(link), 1)
}
return rawBytes
}
// IsSameDomain checks if given url string has the same hostname as current Gitea instance
func IsSameDomain(s string) bool {
if strings.HasPrefix(s, "/") {
return true
}
if uapp, err := url.Parse(setting.AppURL); err == nil {
if u, err := url.Parse(s); err == nil {
return u.Host == uapp.Host
}
return false
}
return false
}
// renderFullSha1Pattern renders SHA containing URLs
func renderFullSha1Pattern(rawBytes []byte, urlPrefix string) []byte {
ms := AnySHA1Pattern.FindAllSubmatch(rawBytes, -1)
for _, m := range ms {
all := m[0]
protocol := string(m[1])
paths := string(m[2])
path := protocol + "://" + paths
author := string(m[3])
repoName := string(m[4])
path = URLJoin(path, author, repoName)
ltype := "src"
itemType := m[5]
if IsSameDomain(paths) {
ltype = string(itemType)
} else if string(itemType) == "commit" {
ltype = "commit"
}
sha := m[6]
var subtree string
if len(m) > 7 && len(m[7]) > 0 {
subtree = string(m[7])
}
var line []byte
if len(m) > 8 && len(m[8]) > 0 {
line = m[8]
}
urlSuffix := ""
text := base.ShortSha(string(sha))
if subtree != "" {
urlSuffix = "/" + subtree
text += urlSuffix
}
if line != nil {
value := string(line)
urlSuffix += "#"
urlSuffix += value
text += " ("
text += value
text += ")"
}
rawBytes = bytes.Replace(rawBytes, all, []byte(fmt.Sprintf(
`<a href="%s">%s</a>`, URLJoin(path, ltype, string(sha))+urlSuffix, text)), -1)
}
return rawBytes
}
// renderFullIssuePattern renders issues-like URLs
func renderFullIssuePattern(rawBytes []byte, urlPrefix string) []byte {
ms := IssueFullPattern.FindAllSubmatch(rawBytes, -1)
for _, m := range ms {
all := m[0]
protocol := string(m[1])
paths := bytes.Split(m[2], []byte("/"))
paths = paths[:len(paths)-1]
if bytes.HasPrefix(paths[0], []byte("gist.")) {
continue
}
path := protocol + "://" + string(m[2])
id := string(m[3])
path = URLJoin(path, id)
var comment []byte
if len(m) > 3 {
comment = m[4]
}
urlSuffix := ""
text := "#" + id
if comment != nil {
urlSuffix += string(comment)
text += " <i class='comment icon'></i>"
}
rawBytes = bytes.Replace(rawBytes, all, []byte(fmt.Sprintf(
`<a href="%s%s">%s</a>`, path, urlSuffix, text)), -1)
}
return rawBytes
}
func firstIndexOfByte(sl []byte, target byte) int {
for i := 0; i < len(sl); i++ {
if sl[i] == target {
return i
}
}
return -1
}
func lastIndexOfByte(sl []byte, target byte) int {
for i := len(sl) - 1; i >= 0; i-- {
if sl[i] == target {
return i
}
}
return -1
}
// RenderShortLinks processes [[syntax]]
//
// noLink flag disables making link tags when set to true
// so this function just replaces the whole [[...]] with the content text
//
// isWikiMarkdown is a flag to choose linking url prefix
func RenderShortLinks(rawBytes []byte, urlPrefix string, noLink bool, isWikiMarkdown bool) []byte {
ms := ShortLinkPattern.FindAll(rawBytes, -1)
for _, m := range ms {
orig := bytes.TrimSpace(m)
m = orig[2:]
tailPos := lastIndexOfByte(m, ']') + 1
tail := []byte{}
if tailPos < len(m) {
tail = m[tailPos:]
m = m[:tailPos-1]
}
m = m[:len(m)-2]
props := map[string]string{}
// MediaWiki uses [[link|text]], while GitHub uses [[text|link]]
// It makes page handling terrible, but we prefer GitHub syntax
// And fall back to MediaWiki only when it is obvious from the look
// Of text and link contents
sl := bytes.Split(m, []byte("|"))
for _, v := range sl {
switch bytes.Count(v, []byte("=")) {
// Piped args without = sign, these are mandatory arguments
case 0:
{
sv := string(v)
if props["name"] == "" {
if isLink(v) {
// If we clearly see it is a link, we save it so
// But first we need to ensure, that if both mandatory args provided
// look like links, we stick to GitHub syntax
if props["link"] != "" {
props["name"] = props["link"]
}
props["link"] = strings.TrimSpace(sv)
} else {
props["name"] = sv
}
} else {
props["link"] = strings.TrimSpace(sv)
}
}
// Piped args with = sign, these are optional arguments
case 1:
{
sep := firstIndexOfByte(v, '=')
key, val := string(v[:sep]), html.UnescapeString(string(v[sep+1:]))
lastCharIndex := len(val) - 1
if (val[0] == '"' || val[0] == '\'') && (val[lastCharIndex] == '"' || val[lastCharIndex] == '\'') {
val = val[1:lastCharIndex]
}
props[key] = val
}
}
}
var name string
var link string
if props["link"] != "" {
link = props["link"]
} else if props["name"] != "" {
link = props["name"]
}
if props["title"] != "" {
name = props["title"]
} else if props["name"] != "" {
name = props["name"]
} else {
name = link
}
name += string(tail)
image := false
ext := filepath.Ext(string(link))
if ext != "" {
switch ext {
case ".jpg", ".jpeg", ".png", ".tif", ".tiff", ".webp", ".gif", ".bmp", ".ico", ".svg":
{
image = true
}
}
}
absoluteLink := isLink([]byte(link))
if !absoluteLink {
link = strings.Replace(link, " ", "+", -1)
}
if image {
if !absoluteLink {
if IsSameDomain(urlPrefix) {
urlPrefix = strings.Replace(urlPrefix, "/src/", "/raw/", 1)
}
if isWikiMarkdown {
link = URLJoin("wiki", "raw", link)
}
link = URLJoin(urlPrefix, link)
}
title := props["title"]
if title == "" {
title = props["alt"]
}
if title == "" {
title = path.Base(string(name))
}
alt := props["alt"]
if alt == "" {
alt = name
}
if alt != "" {
alt = `alt="` + alt + `"`
}
name = fmt.Sprintf(`<img src="%s" %s title="%s" />`, link, alt, title)
} else if !absoluteLink {
if isWikiMarkdown {
link = URLJoin("wiki", link)
}
link = URLJoin(urlPrefix, link)
}
if noLink {
rawBytes = bytes.Replace(rawBytes, orig, []byte(name), -1)
} else {
rawBytes = bytes.Replace(rawBytes, orig,
[]byte(fmt.Sprintf(`<a href="%s">%s</a>`, link, name)), -1)
}
}
return rawBytes
}
// RenderCrossReferenceIssueIndexPattern renders issue indexes from other repositories to corresponding links.
func RenderCrossReferenceIssueIndexPattern(rawBytes []byte, urlPrefix string, metas map[string]string) []byte {
ms := CrossReferenceIssueNumericPattern.FindAll(rawBytes, -1)
for _, m := range ms {
if m[0] == ' ' || m[0] == '(' {
m = m[1:] // ignore leading space or opening parentheses
}
repo := string(bytes.Split(m, []byte("#"))[0])
issue := string(bytes.Split(m, []byte("#"))[1])
link := fmt.Sprintf(`<a href="%s">%s</a>`, URLJoin(setting.AppURL, repo, "issues", issue), m)
rawBytes = bytes.Replace(rawBytes, m, []byte(link), 1)
}
return rawBytes
}
// renderSha1CurrentPattern renders SHA1 strings to corresponding links that assumes in the same repository.
func renderSha1CurrentPattern(rawBytes []byte, urlPrefix string) []byte {
ms := Sha1CurrentPattern.FindAllSubmatch(rawBytes, -1)
for _, m := range ms {
hash := m[1]
if com.StrTo(hash).MustInt() > 0 {
continue
}
rawBytes = bytes.Replace(rawBytes, hash, []byte(fmt.Sprintf(
`<a href="%s">%s</a>`, URLJoin(urlPrefix, "commit", string(hash)), base.ShortSha(string(hash)))), -1)
}
return rawBytes
}
// RenderSpecialLink renders mentions, indexes and SHA1 strings to corresponding links.
func RenderSpecialLink(rawBytes []byte, urlPrefix string, metas map[string]string, isWikiMarkdown bool) []byte {
ms := MentionPattern.FindAll(rawBytes, -1)
for _, m := range ms {
m = m[bytes.Index(m, []byte("@")):]
rawBytes = bytes.Replace(rawBytes, m,
[]byte(fmt.Sprintf(`<a href="%s">%s</a>`, URLJoin(setting.AppURL, string(m[1:])), m)), -1)
}
rawBytes = RenderShortLinks(rawBytes, urlPrefix, false, isWikiMarkdown)
rawBytes = RenderIssueIndexPattern(rawBytes, urlPrefix, metas)
rawBytes = RenderCrossReferenceIssueIndexPattern(rawBytes, urlPrefix, metas)
rawBytes = renderFullSha1Pattern(rawBytes, urlPrefix)
rawBytes = renderSha1CurrentPattern(rawBytes, urlPrefix)
rawBytes = renderFullIssuePattern(rawBytes, urlPrefix)
return rawBytes
}
// RenderRaw renders Markdown to HTML without handling special links.
func RenderRaw(body []byte, urlPrefix string, wikiMarkdown bool) []byte {
htmlFlags := 0
htmlFlags |= blackfriday.HTML_SKIP_STYLE
htmlFlags |= blackfriday.HTML_OMIT_CONTENTS
renderer := &Renderer{
Renderer: blackfriday.HtmlRenderer(htmlFlags, "", ""),
urlPrefix: urlPrefix,
isWikiMarkdown: wikiMarkdown,
}
// set up the parser
extensions := 0
extensions |= blackfriday.EXTENSION_NO_INTRA_EMPHASIS
extensions |= blackfriday.EXTENSION_TABLES
extensions |= blackfriday.EXTENSION_FENCED_CODE
extensions |= blackfriday.EXTENSION_STRIKETHROUGH
extensions |= blackfriday.EXTENSION_NO_EMPTY_LINE_BEFORE_BLOCK
if setting.Markdown.EnableHardLineBreak {
extensions |= blackfriday.EXTENSION_HARD_LINE_BREAK
}
body = blackfriday.Markdown(body, renderer, extensions)
return body
}
var (
leftAngleBracket = []byte("</")
rightAngleBracket = []byte(">")
)
var noEndTags = []string{"img", "input", "br", "hr"}
// PostProcess treats different types of HTML differently,
// and only renders special links for plain text blocks.
func PostProcess(rawHTML []byte, urlPrefix string, metas map[string]string, isWikiMarkdown bool) []byte {
startTags := make([]string, 0, 5)
var buf bytes.Buffer
tokenizer := html.NewTokenizer(bytes.NewReader(rawHTML))
OUTER_LOOP:
for html.ErrorToken != tokenizer.Next() {
token := tokenizer.Token()
switch token.Type {
case html.TextToken:
buf.Write(RenderSpecialLink([]byte(token.String()), urlPrefix, metas, isWikiMarkdown))
case html.StartTagToken:
buf.WriteString(token.String())
tagName := token.Data
// If this is an excluded tag, we skip processing all output until a close tag is encountered.
if strings.EqualFold("a", tagName) || strings.EqualFold("code", tagName) || strings.EqualFold("pre", tagName) {
stackNum := 1
for html.ErrorToken != tokenizer.Next() {
token = tokenizer.Token()
// Copy the token to the output verbatim
buf.Write(RenderShortLinks([]byte(token.String()), urlPrefix, true, isWikiMarkdown))
if token.Type == html.StartTagToken && !com.IsSliceContainsStr(noEndTags, token.Data) {
stackNum++
}
// If this is the close tag to the outer-most, we are done
if token.Type == html.EndTagToken {
stackNum--
if stackNum <= 0 && strings.EqualFold(tagName, token.Data) {
break
}
}
}
continue OUTER_LOOP
}
if !com.IsSliceContainsStr(noEndTags, tagName) {
startTags = append(startTags, tagName)
}
case html.EndTagToken:
if len(startTags) == 0 {
buf.WriteString(token.String())
break
}
buf.Write(leftAngleBracket)
buf.WriteString(startTags[len(startTags)-1])
buf.Write(rightAngleBracket)
startTags = startTags[:len(startTags)-1]
default:
buf.WriteString(token.String())
}
}
if io.EOF == tokenizer.Err() {
return buf.Bytes()
}
// If we are not at the end of the input, then some other parsing error has occurred,
// so return the input verbatim.
return rawHTML
}
// Render renders Markdown to HTML with all specific handling stuff.
func render(rawBytes []byte, urlPrefix string, metas map[string]string, isWikiMarkdown bool) []byte {
urlPrefix = strings.Replace(urlPrefix, " ", "+", -1)
result := RenderRaw(rawBytes, urlPrefix, isWikiMarkdown)
result = PostProcess(result, urlPrefix, metas, isWikiMarkdown)
result = SanitizeBytes(result)
return result
}
// Render renders Markdown to HTML with all specific handling stuff.
func Render(rawBytes []byte, urlPrefix string, metas map[string]string) []byte {
return render(rawBytes, urlPrefix, metas, false)
}
// RenderString renders Markdown to HTML with special links and returns string type.
func RenderString(raw, urlPrefix string, metas map[string]string) string {
return string(render([]byte(raw), urlPrefix, metas, false))
}
// RenderWiki renders markdown wiki page to HTML and return HTML string
func RenderWiki(rawBytes []byte, urlPrefix string, metas map[string]string) string {
return string(render(rawBytes, urlPrefix, metas, true))
}
var (
// MarkupName describes markup's name
MarkupName = "markdown"
)
func init() {
markup.RegisterParser(Parser{})
}
// Parser implements markup.Parser
type Parser struct {
}
// Name implements markup.Parser
func (Parser) Name() string {
return MarkupName
}
// Extensions implements markup.Parser
func (Parser) Extensions() []string {
return setting.Markdown.FileExtensions
}
// Render implements markup.Parser
func (Parser) Render(rawBytes []byte, urlPrefix string, metas map[string]string, isWiki bool) []byte {
return render(rawBytes, urlPrefix, metas, isWiki)
}