Refactor markup render system (#32612)

This PR removes (almost) all path tricks, and introduces "renderhelper"
package.

Now we can clearly see the rendering behaviors for comment/file/wiki,
more details are in "renderhelper" tests.

Fix #31411 , fix #18592, fix #25632 and maybe more problems. (ps: fix
#32608 by the way)

4 files changed, 9 insertions, 15 deletions

diff --git a/services/mailer/mail.go b/services/mailer/mail.go
index 162e497dc0..8eee32a8c6 100644
--- a/services/mailer/mail.go
+++ b/services/mailer/mail.go
@@ -18,12 +18,12 @@ import (
 
 	activities_model "code.gitea.io/gitea/models/activities"
 	issues_model "code.gitea.io/gitea/models/issues"
+	"code.gitea.io/gitea/models/renderhelper"
 	repo_model "code.gitea.io/gitea/models/repo"
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/base"
 	"code.gitea.io/gitea/modules/emoji"
 	"code.gitea.io/gitea/modules/log"
-	"code.gitea.io/gitea/modules/markup"
 	"code.gitea.io/gitea/modules/markup/markdown"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/timeutil"
@@ -219,10 +219,8 @@ func composeIssueCommentMessages(ctx *mailCommentContext, lang string, recipient
 	}
 
 	// This is the body of the new issue or comment, not the mail body
-	body, err := markdown.RenderString(markup.NewRenderContext(ctx).
-		WithRepoFacade(ctx.Issue.Repo).
-		WithLinks(markup.Links{AbsolutePrefix: true, Base: ctx.Issue.Repo.HTMLURL()}).
-		WithMetas(ctx.Issue.Repo.ComposeMetas(ctx)),
+	rctx := renderhelper.NewRenderContextRepoComment(ctx.Context, ctx.Issue.Repo).WithUseAbsoluteLink(true)
+	body, err := markdown.RenderString(rctx,
 		ctx.Content)
 	if err != nil {
 		return nil, err
diff --git a/services/mailer/mail_release.go b/services/mailer/mail_release.go
index 3298c2273a..af1a7a2662 100644
--- a/services/mailer/mail_release.go
+++ b/services/mailer/mail_release.go
@@ -7,11 +7,11 @@ import (
 	"bytes"
 	"context"
 
+	"code.gitea.io/gitea/models/renderhelper"
 	repo_model "code.gitea.io/gitea/models/repo"
 	user_model "code.gitea.io/gitea/models/user"
 	"code.gitea.io/gitea/modules/base"
 	"code.gitea.io/gitea/modules/log"
-	"code.gitea.io/gitea/modules/markup"
 	"code.gitea.io/gitea/modules/markup/markdown"
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/modules/translation"
@@ -56,10 +56,8 @@ func mailNewRelease(ctx context.Context, lang string, tos []*user_model.User, re
 	locale := translation.NewLocale(lang)
 
 	var err error
-	rel.RenderedNote, err = markdown.RenderString(markup.NewRenderContext(ctx).
-		WithRepoFacade(rel.Repo).
-		WithLinks(markup.Links{Base: rel.Repo.HTMLURL()}).
-		WithMetas(rel.Repo.ComposeMetas(ctx)),
+	rctx := renderhelper.NewRenderContextRepoComment(ctx, rel.Repo).WithUseAbsoluteLink(true)
+	rel.RenderedNote, err = markdown.RenderString(rctx,
 		rel.Note)
 	if err != nil {
 		log.Error("markdown.RenderString(%d): %v", rel.RepoID, err)
diff --git a/services/mailer/mail_test.go b/services/mailer/mail_test.go
index 40fd21dea5..663ffa85ef 100644
--- a/services/mailer/mail_test.go
+++ b/services/mailer/mail_test.go
@@ -70,7 +70,7 @@ func prepareMailerTest(t *testing.T) (doer *user_model.User, repo *repo_model.Re
 func TestComposeIssueCommentMessage(t *testing.T) {
 	doer, _, issue, comment := prepareMailerTest(t)
 
-	markup.Init(&markup.ProcessorHelper{
+	markup.Init(&markup.RenderHelperFuncs{
 		IsUsernameMentionable: func(ctx context.Context, username string) bool {
 			return username == doer.Name
 		},
diff --git a/services/markup/processorhelper.go b/services/markup/processorhelper.go
index 68487fb8db..1f1abf496a 100644
--- a/services/markup/processorhelper.go
+++ b/services/markup/processorhelper.go
@@ -11,10 +11,8 @@ import (
 	gitea_context "code.gitea.io/gitea/services/context"
 )
 
-func ProcessorHelper() *markup.ProcessorHelper {
-	return &markup.ProcessorHelper{
-		ElementDir: "auto", // set dir="auto" for necessary (eg: <p>, <h?>, etc) tags
-
+func ProcessorHelper() *markup.RenderHelperFuncs {
+	return &markup.RenderHelperFuncs{
 		RenderRepoFileCodePreview: renderRepoFileCodePreview,
 		IsUsernameMentionable: func(ctx context.Context, username string) bool {
 			mentionedUser, err := user.GetUserByName(ctx, username)