Restructure markup & markdown to prepare for multiple markup language… (#2411)

* restructure markup & markdown to prepare for multiple markup languages support

* adjust some functions between markdown and markup

* fix tests

* improve the comments

4 files changed, 112 insertions, 1130 deletions

diff --git a/modules/markdown/markdown.go b/modules/markdown/markdown.go
index ed673f2056..6cf2d9eaa1 100644
--- a/modules/markdown/markdown.go
+++ b/modules/markdown/markdown.go
@@ -6,107 +6,14 @@ 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 (
-	// NOTE: All below regex matching do not perform any extra validation.
-	// Thus a link is produced even if the user does not exist, the issue does not exist, the commit does not exist, etc.
-	// While fast, this is also incorrect and lead to false positives.
-
-	// 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
-	// Although SHA1 hashes are 40 chars long, the regex matches the hash from 7 to 40 chars in length
-	// so that abbreviated hash links can be used as well. This matches git and github useability.
-	Sha1CurrentPattern = regexp.MustCompile(`(?:^|\s|\()([0-9a-f]{7,40})\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+))?)?`)
-
-	validLinksPattern = regexp.MustCompile(`^[a-z][\w-]+://`)
-)
-
-// regexp for full links to issues/pulls
-var issueFullPattern *regexp.Regexp
-
-// InitMarkdown initialize regexps for markdown parsing
-func InitMarkdown() {
-	getIssueFullPattern()
-}
-
-func getIssueFullPattern() *regexp.Regexp {
-	if issueFullPattern == nil {
-		appURL := setting.AppURL
-		if len(appURL) > 0 && appURL[len(appURL)-1] != '/' {
-			appURL += "/"
-		}
-		issueFullPattern = regexp.MustCompile(appURL +
-			`\w+/\w+/(?:issues|pulls)/((?:\w{1,10}-)?[1-9][0-9]*)([\?|#]\S+.(\S+)?)?\b`)
-	}
-	return issueFullPattern
-}
-
-// 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
@@ -116,13 +23,13 @@ type Renderer struct {
 
 // 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 len(link) > 0 && !markup.IsLink(link) {
 		if link[0] != '#' {
 			lnk := string(link)
 			if r.isWikiMarkdown {
-				lnk = URLJoin("wiki", lnk)
+				lnk = markup.URLJoin("wiki", lnk)
 			}
-			mLink := URLJoin(r.urlPrefix, lnk)
+			mLink := markup.URLJoin(r.urlPrefix, lnk)
 			link = []byte(mLink)
 		}
 	}
@@ -190,11 +97,11 @@ var (
 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 = markup.URLJoin(prefix, "wiki", "src")
 	}
 	prefix = strings.Replace(prefix, "/src/", "/raw/", 1)
 	if len(link) > 0 {
-		if isLink(link) {
+		if markup.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) {
@@ -203,7 +110,7 @@ func (r *Renderer) Image(out *bytes.Buffer, link []byte, title []byte, alt []byt
 			}
 		} else {
 			lnk := string(link)
-			lnk = URLJoin(prefix, lnk)
+			lnk = markup.URLJoin(prefix, lnk)
 			lnk = strings.Replace(lnk, " ", "+", -1)
 			link = []byte(lnk)
 		}
@@ -216,351 +123,6 @@ func (r *Renderer) Image(out *bytes.Buffer, link []byte, title []byte, alt []byt
 	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) []byte {
-	ms := getIssueFullPattern().FindAllSubmatch(rawBytes, -1)
-	for _, m := range ms {
-		all := m[0]
-		id := string(m[1])
-		text := "#" + id
-		// TODO if m[2] is not nil, then link is to a comment,
-		// and we should indicate that in the text somehow
-		rawBytes = bytes.Replace(rawBytes, all, []byte(fmt.Sprintf(
-			`<a href="%s">%s</a>`, string(all), 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]
-		// The regex does not lie, it matches the hash pattern.
-		// However, a regex cannot know if a hash actually exists or not.
-		// We could assume that a SHA1 hash should probably contain alphas AND numerics
-		// but that is not always the case.
-		// Although unlikely, deadbeef and 1234567 are valid short forms of SHA1 hash
-		// as used by git and github for linking and thus we have to do similar.
-		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 = RenderFullIssuePattern(rawBytes)
-	rawBytes = RenderShortLinks(rawBytes, urlPrefix, false, isWikiMarkdown)
-	rawBytes = RenderIssueIndexPattern(rawBytes, urlPrefix, metas)
-	rawBytes = RenderCrossReferenceIssueIndexPattern(rawBytes, urlPrefix, metas)
-	rawBytes = renderFullSha1Pattern(rawBytes, urlPrefix)
-	rawBytes = renderSha1CurrentPattern(rawBytes, urlPrefix)
-	return rawBytes
-}
-
 // RenderRaw renders Markdown to HTML without handling special links.
 func RenderRaw(body []byte, urlPrefix string, wikiMarkdown bool) []byte {
 	htmlFlags := 0
@@ -589,107 +151,6 @@ func RenderRaw(body []byte, urlPrefix string, wikiMarkdown bool) []byte {
 }
 
 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"
 )
@@ -714,5 +175,26 @@ func (Parser) Extensions() []string {
 
 // Render implements markup.Parser
 func (Parser) Render(rawBytes []byte, urlPrefix string, metas map[string]string, isWiki bool) []byte {
-	return render(rawBytes, urlPrefix, metas, isWiki)
+	return RenderRaw(rawBytes, urlPrefix, isWiki)
+}
+
+// Render renders Markdown to HTML with all specific handling stuff.
+func Render(rawBytes []byte, urlPrefix string, metas map[string]string) []byte {
+	return markup.Render("a.md", rawBytes, urlPrefix, metas)
+}
+
+// RenderString renders Markdown to HTML with special links and returns string type.
+func RenderString(raw, urlPrefix string, metas map[string]string) string {
+	return markup.RenderString("a.md", raw, urlPrefix, metas)
+}
+
+// RenderWiki renders markdown wiki page to HTML and return HTML string
+func RenderWiki(rawBytes []byte, urlPrefix string, metas map[string]string) string {
+	return markup.RenderWiki("a.md", rawBytes, urlPrefix, metas)
+}
+
+// IsMarkdownFile reports whether name looks like a Markdown file
+// based on its extension.
+func IsMarkdownFile(name string) bool {
+	return markup.IsMarkupFile(name, MarkupName)
 }
diff --git a/modules/markdown/markdown_test.go b/modules/markdown/markdown_test.go
index 4506a29b1e..1b57e4f203 100644
--- a/modules/markdown/markdown_test.go
+++ b/modules/markdown/markdown_test.go
@@ -7,12 +7,13 @@ package markdown_test
 import (
 	"fmt"
 	"strconv"
-	"testing"
-
 	"strings"
+	"testing"
 
 	. "code.gitea.io/gitea/modules/markdown"
+	"code.gitea.io/gitea/modules/markup"
 	"code.gitea.io/gitea/modules/setting"
+
 	"github.com/stretchr/testify/assert"
 )
 
@@ -24,24 +25,24 @@ var numericMetas = map[string]string{
 	"format": "https://someurl.com/{user}/{repo}/{index}",
 	"user":   "someUser",
 	"repo":   "someRepo",
-	"style":  IssueNameStyleNumeric,
+	"style":  markup.IssueNameStyleNumeric,
 }
 
 var alphanumericMetas = map[string]string{
 	"format": "https://someurl.com/{user}/{repo}/{index}",
 	"user":   "someUser",
 	"repo":   "someRepo",
-	"style":  IssueNameStyleAlphanumeric,
+	"style":  markup.IssueNameStyleAlphanumeric,
 }
 
 // numericLink an HTML to a numeric-style issue
 func numericIssueLink(baseURL string, index int) string {
-	return link(URLJoin(baseURL, strconv.Itoa(index)), fmt.Sprintf("#%d", index))
+	return link(markup.URLJoin(baseURL, strconv.Itoa(index)), fmt.Sprintf("#%d", index))
 }
 
 // alphanumLink an HTML link to an alphanumeric-style issue
 func alphanumIssueLink(baseURL string, name string) string {
-	return link(URLJoin(baseURL, name), name)
+	return link(markup.URLJoin(baseURL, name), name)
 }
 
 // urlContentsLink an HTML link whose contents is the target URL
@@ -56,175 +57,7 @@ func link(href, contents string) string {
 
 func testRenderIssueIndexPattern(t *testing.T, input, expected string, metas map[string]string) {
 	assert.Equal(t, expected,
-		string(RenderIssueIndexPattern([]byte(input), AppSubURL, metas)))
-}
-
-func TestURLJoin(t *testing.T) {
-	type test struct {
-		Expected string
-		Base     string
-		Elements []string
-	}
-	newTest := func(expected, base string, elements ...string) test {
-		return test{Expected: expected, Base: base, Elements: elements}
-	}
-	for _, test := range []test{
-		newTest("https://try.gitea.io/a/b/c",
-			"https://try.gitea.io", "a/b", "c"),
-		newTest("https://try.gitea.io/a/b/c",
-			"https://try.gitea.io/", "/a/b/", "/c/"),
-		newTest("https://try.gitea.io/a/c",
-			"https://try.gitea.io/", "/a/./b/", "../c/"),
-		newTest("a/b/c",
-			"a", "b/c/"),
-		newTest("a/b/d",
-			"a/", "b/c/", "/../d/"),
-	} {
-		assert.Equal(t, test.Expected, URLJoin(test.Base, test.Elements...))
-	}
-}
-
-func TestRender_IssueIndexPattern(t *testing.T) {
-	// numeric: render inputs without valid mentions
-	test := func(s string) {
-		testRenderIssueIndexPattern(t, s, s, nil)
-		testRenderIssueIndexPattern(t, s, s, numericMetas)
-	}
-
-	// should not render anything when there are no mentions
-	test("")
-	test("this is a test")
-	test("test 123 123 1234")
-	test("#")
-	test("# # #")
-	test("# 123")
-	test("#abcd")
-	test("##1234")
-	test("test#1234")
-	test("#1234test")
-	test(" test #1234test")
-
-	// should not render issue mention without leading space
-	test("test#54321 issue")
-
-	// should not render issue mention without trailing space
-	test("test #54321issue")
-}
-
-func TestRender_IssueIndexPattern2(t *testing.T) {
-	setting.AppURL = AppURL
-	setting.AppSubURL = AppSubURL
-
-	// numeric: render inputs with valid mentions
-	test := func(s, expectedFmt string, indices ...int) {
-		links := make([]interface{}, len(indices))
-		for i, index := range indices {
-			links[i] = numericIssueLink(URLJoin(setting.AppSubURL, "issues"), index)
-		}
-		expectedNil := fmt.Sprintf(expectedFmt, links...)
-		testRenderIssueIndexPattern(t, s, expectedNil, nil)
-
-		for i, index := range indices {
-			links[i] = numericIssueLink("https://someurl.com/someUser/someRepo/", index)
-		}
-		expectedNum := fmt.Sprintf(expectedFmt, links...)
-		testRenderIssueIndexPattern(t, s, expectedNum, numericMetas)
-	}
-
-	// should render freestanding mentions
-	test("#1234 test", "%s test", 1234)
-	test("test #8 issue", "test %s issue", 8)
-	test("test issue #1234", "test issue %s", 1234)
-
-	// should render mentions in parentheses
-	test("(#54321 issue)", "(%s issue)", 54321)
-	test("test (#9801 extra) issue", "test (%s extra) issue", 9801)
-	test("test (#1)", "test (%s)", 1)
-
-	// should render multiple issue mentions in the same line
-	test("#54321 #1243", "%s %s", 54321, 1243)
-	test("wow (#54321 #1243)", "wow (%s %s)", 54321, 1243)
-	test("(#4)(#5)", "(%s)(%s)", 4, 5)
-	test("#1 (#4321) test", "%s (%s) test", 1, 4321)
-}
-
-func TestRender_IssueIndexPattern3(t *testing.T) {
-	setting.AppURL = AppURL
-	setting.AppSubURL = AppSubURL
-
-	// alphanumeric: render inputs without valid mentions
-	test := func(s string) {
-		testRenderIssueIndexPattern(t, s, s, alphanumericMetas)
-	}
-	test("")
-	test("this is a test")
-	test("test 123 123 1234")
-	test("#")
-	test("##1234")
-	test("# 123")
-	test("#abcd")
-	test("test #123")
-	test("abc-1234")         // issue prefix must be capital
-	test("ABc-1234")         // issue prefix must be _all_ capital
-	test("ABCDEFGHIJK-1234") // the limit is 10 characters in the prefix
-	test("ABC1234")          // dash is required
-	test("test ABC- test")   // number is required
-	test("test -1234 test")  // prefix is required
-	test("testABC-123 test") // leading space is required
-	test("test ABC-123test") // trailing space is required
-	test("ABC-0123")         // no leading zero
-}
-
-func TestRender_IssueIndexPattern4(t *testing.T) {
-	setting.AppURL = AppURL
-	setting.AppSubURL = AppSubURL
-
-	// alphanumeric: render inputs with valid mentions
-	test := func(s, expectedFmt string, names ...string) {
-		links := make([]interface{}, len(names))
-		for i, name := range names {
-			links[i] = alphanumIssueLink("https://someurl.com/someUser/someRepo/", name)
-		}
-		expected := fmt.Sprintf(expectedFmt, links...)
-		testRenderIssueIndexPattern(t, s, expected, alphanumericMetas)
-	}
-	test("OTT-1234 test", "%s test", "OTT-1234")
-	test("test T-12 issue", "test %s issue", "T-12")
-	test("test issue ABCDEFGHIJ-1234567890", "test issue %s", "ABCDEFGHIJ-1234567890")
-}
-
-func TestRender_AutoLink(t *testing.T) {
-	setting.AppURL = AppURL
-	setting.AppSubURL = AppSubURL
-
-	test := func(input, expected string) {
-		buffer := RenderSpecialLink([]byte(input), setting.AppSubURL, nil, false)
-		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(string(buffer)))
-		buffer = RenderSpecialLink([]byte(input), setting.AppSubURL, nil, true)
-		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(string(buffer)))
-	}
-
-	// render valid issue URLs
-	test(URLJoin(setting.AppSubURL, "issues", "3333"),
-		numericIssueLink(URLJoin(setting.AppSubURL, "issues"), 3333))
-
-	// render external issue URLs
-	for _, externalURL := range []string{
-		"http://1111/2222/ssss-issues/3333?param=blah&blahh=333",
-		"http://test.com/issues/33333",
-		"https://issues/333"} {
-		test(externalURL, externalURL)
-	}
-
-	// render valid commit URLs
-	tmp := URLJoin(AppSubURL, "commit", "d8a994ef243349f321568f9e36d5c3f444b99cae")
-	test(tmp, "<a href=\""+tmp+"\">d8a994ef24</a>")
-	tmp += "#diff-2"
-	test(tmp, "<a href=\""+tmp+"\">d8a994ef24 (diff-2)</a>")
-
-	// render other commit URLs
-	tmp = "https://external-link.gogs.io/gogs/gogs/commit/d8a994ef243349f321568f9e36d5c3f444b99cae#diff-2"
-	test(tmp, "<a href=\""+tmp+"\">d8a994ef24 (diff-2)</a>")
+		string(markup.RenderIssueIndexPattern([]byte(input), AppSubURL, metas)))
 }
 
 func TestRender_StandardLinks(t *testing.T) {
@@ -241,8 +74,8 @@ func TestRender_StandardLinks(t *testing.T) {
 	googleRendered := `<p><a href="https://google.com/" rel="nofollow">https://google.com/</a></p>`
 	test("<https://google.com/>", googleRendered, googleRendered)
 
-	lnk := URLJoin(AppSubURL, "WikiPage")
-	lnkWiki := URLJoin(AppSubURL, "wiki", "WikiPage")
+	lnk := markup.URLJoin(AppSubURL, "WikiPage")
+	lnkWiki := markup.URLJoin(AppSubURL, "wiki", "WikiPage")
 	test("[WikiPage](WikiPage)",
 		`<p><a href="`+lnk+`" rel="nofollow">WikiPage</a></p>`,
 		`<p><a href="`+lnkWiki+`" rel="nofollow">WikiPage</a></p>`)
@@ -251,7 +84,7 @@ func TestRender_StandardLinks(t *testing.T) {
 func TestRender_ShortLinks(t *testing.T) {
 	setting.AppURL = AppURL
 	setting.AppSubURL = AppSubURL
-	tree := URLJoin(AppSubURL, "src", "master")
+	tree := markup.URLJoin(AppSubURL, "src", "master")
 
 	test := func(input, expected, expectedWiki string) {
 		buffer := RenderString(input, tree, nil)
@@ -260,13 +93,13 @@ func TestRender_ShortLinks(t *testing.T) {
 		assert.Equal(t, strings.TrimSpace(expectedWiki), strings.TrimSpace(string(buffer)))
 	}
 
-	rawtree := URLJoin(AppSubURL, "raw", "master")
-	url := URLJoin(tree, "Link")
-	otherUrl := URLJoin(tree, "OtherLink")
-	imgurl := URLJoin(rawtree, "Link.jpg")
-	urlWiki := URLJoin(AppSubURL, "wiki", "Link")
-	otherUrlWiki := URLJoin(AppSubURL, "wiki", "OtherLink")
-	imgurlWiki := URLJoin(AppSubURL, "wiki", "raw", "Link.jpg")
+	rawtree := markup.URLJoin(AppSubURL, "raw", "master")
+	url := markup.URLJoin(tree, "Link")
+	otherUrl := markup.URLJoin(tree, "OtherLink")
+	imgurl := markup.URLJoin(rawtree, "Link.jpg")
+	urlWiki := markup.URLJoin(AppSubURL, "wiki", "Link")
+	otherUrlWiki := markup.URLJoin(AppSubURL, "wiki", "OtherLink")
+	imgurlWiki := markup.URLJoin(AppSubURL, "wiki", "raw", "Link.jpg")
 	favicon := "http://google.com/favicon.ico"
 
 	test(
@@ -311,27 +144,26 @@ func TestRender_ShortLinks(t *testing.T) {
 		`<p><a href="`+urlWiki+`" rel="nofollow">Link</a> <a href="`+otherUrlWiki+`" rel="nofollow">OtherLink</a></p>`)
 }
 
-func TestRender_Commits(t *testing.T) {
-	setting.AppURL = AppURL
-	setting.AppSubURL = AppSubURL
-
-	test := func(input, expected string) {
-		buffer := RenderString(input, setting.AppSubURL, nil)
-		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(string(buffer)))
+func TestMisc_IsMarkdownFile(t *testing.T) {
+	setting.Markdown.FileExtensions = []string{".md", ".markdown", ".mdown", ".mkd"}
+	trueTestCases := []string{
+		"test.md",
+		"wow.MARKDOWN",
+		"LOL.mDoWn",
+	}
+	falseTestCases := []string{
+		"test",
+		"abcdefg",
+		"abcdefghijklmnopqrstuvwxyz",
+		"test.md.test",
 	}
 
-	var sha = "b6dd6210eaebc915fd5be5579c58cce4da2e2579"
-	var commit = URLJoin(AppSubURL, "commit", sha)
-	var subtree = URLJoin(commit, "src")
-	var tree = strings.Replace(subtree, "/commit/", "/tree/", -1)
-	var src = strings.Replace(subtree, "/commit/", "/src/", -1)
-
-	test(sha, `<p><a href="`+commit+`" rel="nofollow">b6dd6210ea</a></p>`)
-	test(sha[:7], `<p><a href="`+commit[:len(commit)-(40-7)]+`" rel="nofollow">b6dd621</a></p>`)
-	test(sha[:39], `<p><a href="`+commit[:len(commit)-(40-39)]+`" rel="nofollow">b6dd6210ea</a></p>`)
-	test(commit, `<p><a href="`+commit+`" rel="nofollow">b6dd6210ea</a></p>`)
-	test(tree, `<p><a href="`+src+`" rel="nofollow">b6dd6210ea/src</a></p>`)
-	test("commit "+sha, `<p>commit <a href="`+commit+`" rel="nofollow">b6dd6210ea</a></p>`)
+	for _, testCase := range trueTestCases {
+		assert.True(t, IsMarkdownFile(testCase))
+	}
+	for _, testCase := range falseTestCases {
+		assert.False(t, IsMarkdownFile(testCase))
+	}
 }
 
 func TestRender_Images(t *testing.T) {
@@ -345,7 +177,7 @@ func TestRender_Images(t *testing.T) {
 
 	url := "../../.images/src/02/train.jpg"
 	title := "Train"
-	result := URLJoin(AppSubURL, url)
+	result := markup.URLJoin(AppSubURL, url)
 
 	test(
 		"!["+title+"]("+url+")",
@@ -356,143 +188,6 @@ func TestRender_Images(t *testing.T) {
 		`<p><a href="`+result+`" rel="nofollow"><img src="`+result+`" alt="`+title+`" title="`+title+`"/></a></p>`)
 }
 
-func TestRender_CrossReferences(t *testing.T) {
-	setting.AppURL = AppURL
-	setting.AppSubURL = AppSubURL
-
-	test := func(input, expected string) {
-		buffer := RenderString(input, setting.AppSubURL, nil)
-		assert.Equal(t, strings.TrimSpace(expected), strings.TrimSpace(string(buffer)))
-	}
-
-	test(
-		"gogits/gogs#12345",
-		`<p><a href="`+URLJoin(AppURL, "gogits", "gogs", "issues", "12345")+`" rel="nofollow">gogits/gogs#12345</a></p>`)
-}
-
-func TestRender_FullIssueURLs(t *testing.T) {
-	setting.AppURL = AppURL
-	setting.AppSubURL = AppSubURL
-
-	test := func(input, expected string) {
-		result := RenderFullIssuePattern([]byte(input))
-		assert.Equal(t, expected, string(result))
-	}
-	test("Here is a link https://git.osgeo.org/gogs/postgis/postgis/pulls/6",
-		"Here is a link https://git.osgeo.org/gogs/postgis/postgis/pulls/6")
-	test("Look here http://localhost:3000/person/repo/issues/4",
-		`Look here <a href="http://localhost:3000/person/repo/issues/4">#4</a>`)
-	test("http://localhost:3000/person/repo/issues/4#issuecomment-1234",
-		`<a href="http://localhost:3000/person/repo/issues/4#issuecomment-1234">#4</a>`)
-}
-
-func TestRegExp_MentionPattern(t *testing.T) {
-	trueTestCases := []string{
-		"@Unknwon",
-		"@ANT_123",
-		"@xxx-DiN0-z-A..uru..s-xxx",
-		"   @lol   ",
-		" @Te/st",
-	}
-	falseTestCases := []string{
-		"@ 0",
-		"@ ",
-		"@",
-		"",
-		"ABC",
-	}
-
-	for _, testCase := range trueTestCases {
-		res := MentionPattern.MatchString(testCase)
-		if !res {
-			println()
-			println(testCase)
-		}
-		assert.True(t, res)
-	}
-	for _, testCase := range falseTestCases {
-		res := MentionPattern.MatchString(testCase)
-		if res {
-			println()
-			println(testCase)
-		}
-		assert.False(t, res)
-	}
-}
-
-func TestRegExp_IssueNumericPattern(t *testing.T) {
-	trueTestCases := []string{
-		"#1234",
-		"#0",
-		"#1234567890987654321",
-	}
-	falseTestCases := []string{
-		"# 1234",
-		"# 0",
-		"# ",
-		"#",
-		"#ABC",
-		"#1A2B",
-		"",
-		"ABC",
-	}
-
-	for _, testCase := range trueTestCases {
-		assert.True(t, IssueNumericPattern.MatchString(testCase))
-	}
-	for _, testCase := range falseTestCases {
-		assert.False(t, IssueNumericPattern.MatchString(testCase))
-	}
-}
-
-func TestRegExp_IssueAlphanumericPattern(t *testing.T) {
-	trueTestCases := []string{
-		"ABC-1234",
-		"A-1",
-		"RC-80",
-		"ABCDEFGHIJ-1234567890987654321234567890",
-	}
-	falseTestCases := []string{
-		"RC-08",
-		"PR-0",
-		"ABCDEFGHIJK-1",
-		"PR_1",
-		"",
-		"#ABC",
-		"",
-		"ABC",
-		"GG-",
-		"rm-1",
-	}
-
-	for _, testCase := range trueTestCases {
-		assert.True(t, IssueAlphanumericPattern.MatchString(testCase))
-	}
-	for _, testCase := range falseTestCases {
-		assert.False(t, IssueAlphanumericPattern.MatchString(testCase))
-	}
-}
-
-func TestRegExp_Sha1CurrentPattern(t *testing.T) {
-	trueTestCases := []string{
-		"d8a994ef243349f321568f9e36d5c3f444b99cae",
-		"abcdefabcdefabcdefabcdefabcdefabcdefabcd",
-	}
-	falseTestCases := []string{
-		"test",
-		"abcdefg",
-		"abcdefghijklmnopqrstuvwxyzabcdefghijklmn",
-		"abcdefghijklmnopqrstuvwxyzabcdefghijklmO",
-	}
-
-	for _, testCase := range trueTestCases {
-		assert.True(t, Sha1CurrentPattern.MatchString(testCase))
-	}
-	for _, testCase := range falseTestCases {
-		assert.False(t, Sha1CurrentPattern.MatchString(testCase))
-	}
-}
-
 func TestRegExp_ShortLinkPattern(t *testing.T) {
 	trueTestCases := []string{
 		"[[stuff]]",
@@ -510,139 +205,13 @@ func TestRegExp_ShortLinkPattern(t *testing.T) {
 	}
 
 	for _, testCase := range trueTestCases {
-		assert.True(t, ShortLinkPattern.MatchString(testCase))
+		assert.True(t, markup.ShortLinkPattern.MatchString(testCase))
 	}
 	for _, testCase := range falseTestCases {
-		assert.False(t, ShortLinkPattern.MatchString(testCase))
+		assert.False(t, markup.ShortLinkPattern.MatchString(testCase))
 	}
 }
 
-func TestRegExp_AnySHA1Pattern(t *testing.T) {
-	testCases := map[string][]string{
-		"https://github.com/jquery/jquery/blob/a644101ed04d0beacea864ce805e0c4f86ba1cd1/test/unit/event.js#L2703": {
-			"https",
-			"github.com",
-			"jquery",
-			"jquery",
-			"blob",
-			"a644101ed04d0beacea864ce805e0c4f86ba1cd1",
-			"test/unit/event.js",
-			"L2703",
-		},
-		"https://github.com/jquery/jquery/blob/a644101ed04d0beacea864ce805e0c4f86ba1cd1/test/unit/event.js": {
-			"https",
-			"github.com",
-			"jquery",
-			"jquery",
-			"blob",
-			"a644101ed04d0beacea864ce805e0c4f86ba1cd1",
-			"test/unit/event.js",
-			"",
-		},
-		"https://github.com/jquery/jquery/commit/0705be475092aede1eddae01319ec931fb9c65fc": {
-			"https",
-			"github.com",
-			"jquery",
-			"jquery",
-			"commit",
-			"0705be475092aede1eddae01319ec931fb9c65fc",
-			"",
-			"",
-		},
-		"https://github.com/jquery/jquery/tree/0705be475092aede1eddae01319ec931fb9c65fc/src": {
-			"https",
-			"github.com",
-			"jquery",
-			"jquery",
-			"tree",
-			"0705be475092aede1eddae01319ec931fb9c65fc",
-			"src",
-			"",
-		},
-		"https://try.gogs.io/gogs/gogs/commit/d8a994ef243349f321568f9e36d5c3f444b99cae#diff-2": {
-			"https",
-			"try.gogs.io",
-			"gogs",
-			"gogs",
-			"commit",
-			"d8a994ef243349f321568f9e36d5c3f444b99cae",
-			"",
-			"diff-2",
-		},
-	}
-
-	for k, v := range testCases {
-		assert.Equal(t, AnySHA1Pattern.FindStringSubmatch(k)[1:], v)
-	}
-}
-
-func TestMisc_IsMarkdownFile(t *testing.T) {
-	setting.Markdown.FileExtensions = []string{".md", ".markdown", ".mdown", ".mkd"}
-	trueTestCases := []string{
-		"test.md",
-		"wow.MARKDOWN",
-		"LOL.mDoWn",
-	}
-	falseTestCases := []string{
-		"test",
-		"abcdefg",
-		"abcdefghijklmnopqrstuvwxyz",
-		"test.md.test",
-	}
-
-	for _, testCase := range trueTestCases {
-		assert.True(t, IsMarkdownFile(testCase))
-	}
-	for _, testCase := range falseTestCases {
-		assert.False(t, IsMarkdownFile(testCase))
-	}
-}
-
-func TestMisc_IsSameDomain(t *testing.T) {
-	setting.AppURL = AppURL
-	setting.AppSubURL = AppSubURL
-
-	var sha = "b6dd6210eaebc915fd5be5579c58cce4da2e2579"
-	var commit = URLJoin(AppSubURL, "commit", sha)
-
-	assert.True(t, IsSameDomain(commit))
-	assert.False(t, IsSameDomain("http://google.com/ncr"))
-	assert.False(t, IsSameDomain("favicon.ico"))
-}
-
-// Test cases without ambiguous links
-var sameCases = []string{
-	// dear imgui wiki markdown extract: special wiki syntax
-	`Wiki! Enjoy :)
-- [[Links, Language bindings, Engine bindings|Links]]
-- [[Tips]]
-
-Ideas and codes
-
-- Bezier widget (by @r-lyeh) ` + AppURL + `ocornut/imgui/issues/786
-- Node graph editors https://github.com/ocornut/imgui/issues/306
-- [[Memory Editor|memory_editor_example]]
-- [[Plot var helper|plot_var_example]]`,
-	// wine-staging wiki home extract: tables, special wiki syntax, images
-	`## What is Wine Staging?
-**Wine Staging** on website [wine-staging.com](http://wine-staging.com).
-
-## Quick Links
-Here are some links to the most important topics. You can find the full list of pages at the sidebar.
-
-| [[images/icon-install.png]]    | [[Installation]]                                         |
-|--------------------------------|----------------------------------------------------------|
-| [[images/icon-usage.png]]      | [[Usage]]                                                |
-`,
-	// libgdx wiki page: inline images with special syntax
-	`[Excelsior JET](http://www.excelsiorjet.com/) allows you to create native executables for Windows, Linux and Mac OS X.
-
-1. [Package your libGDX application](https://github.com/libgdx/libgdx/wiki/Gradle-on-the-Commandline#packaging-for-the-desktop)
-[[images/1.png]]
-2. Perform a test run by hitting the Run! button.
-[[images/2.png]]`,
-}
-
 func testAnswers(baseURLContent, baseURLImages string) []string {
 	return []string{
 		`<p>Wiki! Enjoy :)</p>
@@ -697,24 +266,41 @@ func testAnswers(baseURLContent, baseURLImages string) []string {
 	}
 }
 
-func TestTotal_RenderString(t *testing.T) {
-	answers := testAnswers(URLJoin(AppSubURL, "src", "master/"), URLJoin(AppSubURL, "raw", "master/"))
+// Test cases without ambiguous links
+var sameCases = []string{
+	// dear imgui wiki markdown extract: special wiki syntax
+	`Wiki! Enjoy :)
+- [[Links, Language bindings, Engine bindings|Links]]
+- [[Tips]]
 
-	for i := 0; i < len(sameCases); i++ {
-		line := RenderString(sameCases[i], URLJoin(AppSubURL, "src", "master/"), nil)
-		assert.Equal(t, answers[i], line)
-	}
+Ideas and codes
 
-	testCases := []string{}
+- Bezier widget (by @r-lyeh) ` + AppURL + `ocornut/imgui/issues/786
+- Node graph editors https://github.com/ocornut/imgui/issues/306
+- [[Memory Editor|memory_editor_example]]
+- [[Plot var helper|plot_var_example]]`,
+	// wine-staging wiki home extract: tables, special wiki syntax, images
+	`## What is Wine Staging?
+**Wine Staging** on website [wine-staging.com](http://wine-staging.com).
 
-	for i := 0; i < len(testCases); i += 2 {
-		line := RenderString(testCases[i], AppSubURL, nil)
-		assert.Equal(t, testCases[i+1], line)
-	}
+## Quick Links
+Here are some links to the most important topics. You can find the full list of pages at the sidebar.
+
+| [[images/icon-install.png]]    | [[Installation]]                                         |
+|--------------------------------|----------------------------------------------------------|
+| [[images/icon-usage.png]]      | [[Usage]]                                                |
+`,
+	// libgdx wiki page: inline images with special syntax
+	`[Excelsior JET](http://www.excelsiorjet.com/) allows you to create native executables for Windows, Linux and Mac OS X.
+
+1. [Package your libGDX application](https://github.com/libgdx/libgdx/wiki/Gradle-on-the-Commandline#packaging-for-the-desktop)
+[[images/1.png]]
+2. Perform a test run by hitting the Run! button.
+[[images/2.png]]`,
 }
 
 func TestTotal_RenderWiki(t *testing.T) {
-	answers := testAnswers(URLJoin(AppSubURL, "wiki/"), URLJoin(AppSubURL, "wiki", "raw/"))
+	answers := testAnswers(markup.URLJoin(AppSubURL, "wiki/"), markup.URLJoin(AppSubURL, "wiki", "raw/"))
 
 	for i := 0; i < len(sameCases); i++ {
 		line := RenderWiki([]byte(sameCases[i]), AppSubURL, nil)
@@ -739,3 +325,19 @@ func TestTotal_RenderWiki(t *testing.T) {
 		assert.Equal(t, testCases[i+1], line)
 	}
 }
+
+func TestTotal_RenderString(t *testing.T) {
+	answers := testAnswers(markup.URLJoin(AppSubURL, "src", "master/"), markup.URLJoin(AppSubURL, "raw", "master/"))
+
+	for i := 0; i < len(sameCases); i++ {
+		line := RenderString(sameCases[i], markup.URLJoin(AppSubURL, "src", "master/"), nil)
+		assert.Equal(t, answers[i], line)
+	}
+
+	testCases := []string{}
+
+	for i := 0; i < len(testCases); i += 2 {
+		line := RenderString(testCases[i], AppSubURL, nil)
+		assert.Equal(t, testCases[i+1], line)
+	}
+}
diff --git a/modules/markdown/sanitizer.go b/modules/markdown/sanitizer.go
deleted file mode 100644
index cc00c9a1a3..0000000000
--- a/modules/markdown/sanitizer.go
+++ /dev/null
@@ -1,58 +0,0 @@
-// Copyright 2017 The Gitea Authors. All rights reserved.
-// Copyright 2017 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 (
-	"regexp"
-	"sync"
-
-	"code.gitea.io/gitea/modules/setting"
-
-	"github.com/microcosm-cc/bluemonday"
-)
-
-// Sanitizer is a protection wrapper of *bluemonday.Policy which does not allow
-// any modification to the underlying policies once it's been created.
-type Sanitizer struct {
-	policy *bluemonday.Policy
-	init   sync.Once
-}
-
-var sanitizer = &Sanitizer{}
-
-// NewSanitizer initializes sanitizer with allowed attributes based on settings.
-// Multiple calls to this function will only create one instance of Sanitizer during
-// entire application lifecycle.
-func NewSanitizer() {
-	sanitizer.init.Do(func() {
-		sanitizer.policy = bluemonday.UGCPolicy()
-		// We only want to allow HighlightJS specific classes for code blocks
-		sanitizer.policy.AllowAttrs("class").Matching(regexp.MustCompile(`^language-\w+$`)).OnElements("code")
-
-		// Checkboxes
-		sanitizer.policy.AllowAttrs("type").Matching(regexp.MustCompile(`^checkbox$`)).OnElements("input")
-		sanitizer.policy.AllowAttrs("checked", "disabled").OnElements("input")
-
-		// Custom URL-Schemes
-		sanitizer.policy.AllowURLSchemes(setting.Markdown.CustomURLSchemes...)
-	})
-}
-
-// Sanitize takes a string that contains a HTML fragment or document and applies policy whitelist.
-func Sanitize(s string) string {
-	NewSanitizer()
-	return sanitizer.policy.Sanitize(s)
-}
-
-// SanitizeBytes takes a []byte slice that contains a HTML fragment or document and applies policy whitelist.
-func SanitizeBytes(b []byte) []byte {
-	if len(b) == 0 {
-		// nothing to sanitize
-		return b
-	}
-	NewSanitizer()
-	return sanitizer.policy.SanitizeBytes(b)
-}
diff --git a/modules/markdown/sanitizer_test.go b/modules/markdown/sanitizer_test.go
deleted file mode 100644
index 77a4b33c84..0000000000
--- a/modules/markdown/sanitizer_test.go
+++ /dev/null
@@ -1,44 +0,0 @@
-// Copyright 2017 The Gitea Authors. All rights reserved.
-// Copyright 2017 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 (
-	"testing"
-
-	"github.com/stretchr/testify/assert"
-)
-
-func Test_Sanitizer(t *testing.T) {
-	NewSanitizer()
-	testCases := []string{
-		// Regular
-		`<a onblur="alert(secret)" href="http://www.google.com">Google</a>`, `<a href="http://www.google.com" rel="nofollow">Google</a>`,
-
-		// Code highlighting class
-		`<code class="random string"></code>`, `<code></code>`,
-		`<code class="language-random ui tab active menu attached animating sidebar following bar center"></code>`, `<code></code>`,
-		`<code class="language-go"></code>`, `<code class="language-go"></code>`,
-
-		// Input checkbox
-		`<input type="hidden">`, ``,
-		`<input type="checkbox">`, `<input type="checkbox">`,
-		`<input checked disabled autofocus>`, `<input checked="" disabled="">`,
-
-		// Code highlight injection
-		`<code class="language-random&#32;ui&#32;tab&#32;active&#32;menu&#32;attached&#32;animating&#32;sidebar&#32;following&#32;bar&#32;center"></code>`, `<code></code>`,
-		`<code class="language-lol&#32;ui&#32;tab&#32;active&#32;menu&#32;attached&#32;animating&#32;sidebar&#32;following&#32;bar&#32;center">
-<code class="language-lol&#32;ui&#32;container&#32;input&#32;huge&#32;basic&#32;segment&#32;center">&nbsp;</code>
-<img src="https://try.gogs.io/img/favicon.png" width="200" height="200">
-<code class="language-lol&#32;ui&#32;container&#32;input&#32;massive&#32;basic&#32;segment">Hello there! Something has gone wrong, we are working on it.</code>
-<code class="language-lol&#32;ui&#32;container&#32;input&#32;huge&#32;basic&#32;segment">In the meantime, play a game with us at&nbsp;<a href="http://example.com/">example.com</a>.</code>
-</code>`, "<code>\n<code>\u00a0</code>\n<img src=\"https://try.gogs.io/img/favicon.png\" width=\"200\" height=\"200\">\n<code>Hello there! Something has gone wrong, we are working on it.</code>\n<code>In the meantime, play a game with us at\u00a0<a href=\"http://example.com/\" rel=\"nofollow\">example.com</a>.</code>\n</code>",
-	}
-
-	for i := 0; i < len(testCases); i += 2 {
-		assert.Equal(t, testCases[i+1], Sanitize(testCases[i]))
-		assert.Equal(t, testCases[i+1], string(SanitizeBytes([]byte(testCases[i]))))
-	}
-}