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

modules/markup/html_mention.go

@@ -0,0 +1,54 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package markup
+
+import (
+	"strings"
+
+	"code.gitea.io/gitea/modules/references"
+	"code.gitea.io/gitea/modules/util"
+
+	"golang.org/x/net/html"
+)
+
+func mentionProcessor(ctx *RenderContext, node *html.Node) {
+	start := 0
+	nodeStop := node.NextSibling
+	for node != nodeStop {
+		found, loc := references.FindFirstMentionBytes(util.UnsafeStringToBytes(node.Data[start:]))
+		if !found {
+			node = node.NextSibling
+			start = 0
+			continue
+		}
+		loc.Start += start
+		loc.End += start
+		mention := node.Data[loc.Start:loc.End]
+		teams, ok := ctx.Metas["teams"]
+		// FIXME: util.URLJoin may not be necessary here:
+		// - setting.AppURL is defined to have a terminal '/' so unless mention[1:]
+		// is an AppSubURL link we can probably fallback to concatenation.
+		// team mention should follow @orgName/teamName style
+		if ok && strings.Contains(mention, "/") {
+			mentionOrgAndTeam := strings.Split(mention, "/")
+			if mentionOrgAndTeam[0][1:] == ctx.Metas["org"] && strings.Contains(teams, ","+strings.ToLower(mentionOrgAndTeam[1])+",") {
+				replaceContent(node, loc.Start, loc.End, createLink(util.URLJoin(ctx.Links.Prefix(), "org", ctx.Metas["org"], "teams", mentionOrgAndTeam[1]), mention, "mention"))
+				node = node.NextSibling.NextSibling
+				start = 0
+				continue
+			}
+			start = loc.End
+			continue
+		}
+		mentionedUsername := mention[1:]
+
+		if DefaultProcessorHelper.IsUsernameMentionable != nil && DefaultProcessorHelper.IsUsernameMentionable(ctx.Ctx, mentionedUsername) {
+			replaceContent(node, loc.Start, loc.End, createLink(util.URLJoin(ctx.Links.Prefix(), mentionedUsername), mention, "mention"))
+			node = node.NextSibling.NextSibling
+			start = 0
+		} else {
+			start = loc.End
+		}
+	}
+}