Refactor markup package (#32399)

To make the markup package easier to maintain:
1. Split some go files into small files
2. Use a shared util.NopCloser, remove duplicate code
3. Remove unused functions

1 files changed, 225 insertions, 0 deletions

diff --git a/modules/markup/html_commit.go b/modules/markup/html_commit.go
new file mode 100644
index 0000000000..86d70746d4
--- /dev/null
+++ b/modules/markup/html_commit.go
@@ -0,0 +1,225 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package markup
+
+import (
+	"io"
+	"slices"
+	"strings"
+
+	"code.gitea.io/gitea/modules/base"
+	"code.gitea.io/gitea/modules/gitrepo"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/util"
+
+	"golang.org/x/net/html"
+	"golang.org/x/net/html/atom"
+)
+
+type anyHashPatternResult struct {
+	PosStart  int
+	PosEnd    int
+	FullURL   string
+	CommitID  string
+	SubPath   string
+	QueryHash string
+}
+
+func createCodeLink(href, content, class string) *html.Node {
+	a := &html.Node{
+		Type: html.ElementNode,
+		Data: atom.A.String(),
+		Attr: []html.Attribute{{Key: "href", Val: href}},
+	}
+
+	if class != "" {
+		a.Attr = append(a.Attr, html.Attribute{Key: "class", Val: class})
+	}
+
+	text := &html.Node{
+		Type: html.TextNode,
+		Data: content,
+	}
+
+	code := &html.Node{
+		Type: html.ElementNode,
+		Data: atom.Code.String(),
+		Attr: []html.Attribute{{Key: "class", Val: "nohighlight"}},
+	}
+
+	code.AppendChild(text)
+	a.AppendChild(code)
+	return a
+}
+
+func anyHashPatternExtract(s string) (ret anyHashPatternResult, ok bool) {
+	m := anyHashPattern.FindStringSubmatchIndex(s)
+	if m == nil {
+		return ret, false
+	}
+
+	ret.PosStart, ret.PosEnd = m[0], m[1]
+	ret.FullURL = s[ret.PosStart:ret.PosEnd]
+	if strings.HasSuffix(ret.FullURL, ".") {
+		// if url ends in '.', it's very likely that it is not part of the actual url but used to finish a sentence.
+		ret.PosEnd--
+		ret.FullURL = ret.FullURL[:len(ret.FullURL)-1]
+		for i := 0; i < len(m); i++ {
+			m[i] = min(m[i], ret.PosEnd)
+		}
+	}
+
+	ret.CommitID = s[m[2]:m[3]]
+	if m[5] > 0 {
+		ret.SubPath = s[m[4]:m[5]]
+	}
+
+	lastStart, lastEnd := m[len(m)-2], m[len(m)-1]
+	if lastEnd > 0 {
+		ret.QueryHash = s[lastStart:lastEnd][1:]
+	}
+	return ret, true
+}
+
+// fullHashPatternProcessor renders SHA containing URLs
+func fullHashPatternProcessor(ctx *RenderContext, node *html.Node) {
+	if ctx.Metas == nil {
+		return
+	}
+	nodeStop := node.NextSibling
+	for node != nodeStop {
+		if node.Type != html.TextNode {
+			node = node.NextSibling
+			continue
+		}
+		ret, ok := anyHashPatternExtract(node.Data)
+		if !ok {
+			node = node.NextSibling
+			continue
+		}
+		text := base.ShortSha(ret.CommitID)
+		if ret.SubPath != "" {
+			text += ret.SubPath
+		}
+		if ret.QueryHash != "" {
+			text += " (" + ret.QueryHash + ")"
+		}
+		replaceContent(node, ret.PosStart, ret.PosEnd, createCodeLink(ret.FullURL, text, "commit"))
+		node = node.NextSibling.NextSibling
+	}
+}
+
+func comparePatternProcessor(ctx *RenderContext, node *html.Node) {
+	if ctx.Metas == nil {
+		return
+	}
+	nodeStop := node.NextSibling
+	for node != nodeStop {
+		if node.Type != html.TextNode {
+			node = node.NextSibling
+			continue
+		}
+		m := comparePattern.FindStringSubmatchIndex(node.Data)
+		if m == nil || slices.Contains(m[:8], -1) { // ensure that every group (m[0]...m[7]) has a match
+			node = node.NextSibling
+			continue
+		}
+
+		urlFull := node.Data[m[0]:m[1]]
+		text1 := base.ShortSha(node.Data[m[2]:m[3]])
+		textDots := base.ShortSha(node.Data[m[4]:m[5]])
+		text2 := base.ShortSha(node.Data[m[6]:m[7]])
+
+		hash := ""
+		if m[9] > 0 {
+			hash = node.Data[m[8]:m[9]][1:]
+		}
+
+		start := m[0]
+		end := m[1]
+
+		// If url ends in '.', it's very likely that it is not part of the
+		// actual url but used to finish a sentence.
+		if strings.HasSuffix(urlFull, ".") {
+			end--
+			urlFull = urlFull[:len(urlFull)-1]
+			if hash != "" {
+				hash = hash[:len(hash)-1]
+			} else if text2 != "" {
+				text2 = text2[:len(text2)-1]
+			}
+		}
+
+		text := text1 + textDots + text2
+		if hash != "" {
+			text += " (" + hash + ")"
+		}
+		replaceContent(node, start, end, createCodeLink(urlFull, text, "compare"))
+		node = node.NextSibling.NextSibling
+	}
+}
+
+// hashCurrentPatternProcessor renders SHA1 strings to corresponding links that
+// are assumed to be in the same repository.
+func hashCurrentPatternProcessor(ctx *RenderContext, node *html.Node) {
+	if ctx.Metas == nil || ctx.Metas["user"] == "" || ctx.Metas["repo"] == "" || (ctx.Repo == nil && ctx.GitRepo == nil) {
+		return
+	}
+
+	start := 0
+	next := node.NextSibling
+	if ctx.ShaExistCache == nil {
+		ctx.ShaExistCache = make(map[string]bool)
+	}
+	for node != nil && node != next && start < len(node.Data) {
+		m := hashCurrentPattern.FindStringSubmatchIndex(node.Data[start:])
+		if m == nil {
+			return
+		}
+		m[2] += start
+		m[3] += start
+
+		hash := node.Data[m[2]:m[3]]
+		// 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.
+		// Because of this, we check to make sure that a matched hash is actually
+		// a commit in the repository before making it a link.
+
+		// check cache first
+		exist, inCache := ctx.ShaExistCache[hash]
+		if !inCache {
+			if ctx.GitRepo == nil {
+				var err error
+				var closer io.Closer
+				ctx.GitRepo, closer, err = gitrepo.RepositoryFromContextOrOpen(ctx.Ctx, ctx.Repo)
+				if err != nil {
+					log.Error("unable to open repository: %s Error: %v", gitrepo.RepoGitURL(ctx.Repo), err)
+					return
+				}
+				ctx.AddCancel(func() {
+					_ = closer.Close()
+					ctx.GitRepo = nil
+				})
+			}
+
+			// Don't use IsObjectExist since it doesn't support short hashs with gogit edition.
+			exist = ctx.GitRepo.IsReferenceExist(hash)
+			ctx.ShaExistCache[hash] = exist
+		}
+
+		if !exist {
+			start = m[3]
+			continue
+		}
+
+		link := util.URLJoin(ctx.Links.Prefix(), ctx.Metas["user"], ctx.Metas["repo"], "commit", hash)
+		replaceContent(node, m[2], m[3], createCodeLink(link, base.ShortSha(hash), "commit"))
+		start = 0
+		node = node.NextSibling.NextSibling
+	}
+}