More efficiently parse shas for shaPostProcessor (#16101)

* More efficiently parse shas for shaPostProcessor

The shaPostProcessor currently repeatedly calls git rev-parse --verify on both backends
which is fine if there is only one thing that matches a sha - however if there are
multiple things then this becomes wildly inefficient.

This PR provides functions for both backends which are much faster to use.

Fix #16092

* Add ShaExistCache to RenderContext

Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: 6543 <6543@obermui.de>

modules/git/repo_branch_gogit.go

@@ -13,6 +13,30 @@ import (
 	"github.com/go-git/go-git/v5/plumbing"
 )
 
+// IsObjectExist returns true if given reference exists in the repository.
+func (repo *Repository) IsObjectExist(name string) bool {
+	if name == "" {
+		return false
+	}
+
+	_, err := repo.gogitRepo.ResolveRevision(plumbing.Revision(name))
+
+	return err == nil
+}
+
+// IsReferenceExist returns true if given reference exists in the repository.
+func (repo *Repository) IsReferenceExist(name string) bool {
+	if name == "" {
+		return false
+	}
+
+	reference, err := repo.gogitRepo.Reference(plumbing.ReferenceName(name), true)
+	if err != nil {
+		return false
+	}
+	return reference.Type() != plumbing.InvalidReference
+}
+
 // IsBranchExist returns true if given branch exists in current repository.
 func (repo *Repository) IsBranchExist(name string) bool {
 	if name == "" {

modules/git/repo_branch_nogogit.go

@@ -9,10 +9,28 @@ package git
 
 import (
 	"bufio"
+	"bytes"
 	"io"
 	"strings"
 )
 
+// IsObjectExist returns true if given reference exists in the repository.
+func (repo *Repository) IsObjectExist(name string) bool {
+	if name == "" {
+		return false
+	}
+
+	wr, rd, cancel := repo.CatFileBatchCheck()
+	defer cancel()
+	_, err := wr.Write([]byte(name + "\n"))
+	if err != nil {
+		log("Error writing to CatFileBatchCheck %v", err)
+		return false
+	}
+	sha, _, _, err := ReadBatchLine(rd)
+	return err == nil && bytes.HasPrefix(sha, []byte(strings.TrimSpace(name)))
+}
+
 // IsReferenceExist returns true if given reference exists in the repository.
 func (repo *Repository) IsReferenceExist(name string) bool {
 	if name == "" {

modules/markup/html.go

@@ -286,6 +286,7 @@ var tagCleaner = regexp.MustCompile(`<((?:/?\w+/\w+)|(?:/[\w ]+/)|(/?[hH][tT][mM
 var nulCleaner = strings.NewReplacer("\000", "")
 
 func postProcess(ctx *RenderContext, procs []processor, input io.Reader, output io.Writer) error {
+	defer ctx.Cancel()
 	// FIXME: don't read all content to memory
 	rawHTML, err := ioutil.ReadAll(input)
 	if err != nil {
@@ -996,6 +997,9 @@ func sha1CurrentPatternProcessor(ctx *RenderContext, node *html.Node) {
 
 	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 := sha1CurrentPattern.FindStringSubmatchIndex(node.Data[start:])
 		if m == nil {
@@ -1013,10 +1017,28 @@ func sha1CurrentPatternProcessor(ctx *RenderContext, node *html.Node) {
 		// 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.
-		if _, err := git.NewCommand("rev-parse", "--verify", hash).RunInDirBytes(ctx.Metas["repoPath"]); err != nil {
+
-			if !strings.Contains(err.Error(), "fatal: Needed a single revision") {
+		// check cache first
-				log.Debug("sha1CurrentPatternProcessor git rev-parse: %v", err)
+		exist, inCache := ctx.ShaExistCache[hash]
+		if !inCache {
+			if ctx.GitRepo == nil {
+				var err error
+				ctx.GitRepo, err = git.OpenRepository(ctx.Metas["repoPath"])
+				if err != nil {
+					log.Error("unable to open repository: %s Error: %v", ctx.Metas["repoPath"], err)
+					return
 				}
+				ctx.AddCancel(func() {
+					ctx.GitRepo.Close()
+					ctx.GitRepo = nil
+				})
+			}
+
+			exist = ctx.GitRepo.IsObjectExist(hash)
+			ctx.ShaExistCache[hash] = exist
+		}
+
+		if !exist {
 			start = m[3]
 			continue
 		}

modules/markup/renderer.go

@@ -13,6 +13,7 @@ import (
 	"strings"
 	"sync"
 
+	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/setting"
 )
 
@@ -42,6 +43,37 @@ type RenderContext struct {
 	URLPrefix     string
 	Metas         map[string]string
 	DefaultLink   string
+	GitRepo       *git.Repository
+	ShaExistCache map[string]bool
+	cancelFn      func()
+}
+
+// Cancel runs any cleanup functions that have been registered for this Ctx
+func (ctx *RenderContext) Cancel() {
+	if ctx == nil {
+		return
+	}
+	ctx.ShaExistCache = map[string]bool{}
+	if ctx.cancelFn == nil {
+		return
+	}
+	ctx.cancelFn()
+}
+
+// AddCancel adds the provided fn as a Cleanup for this Ctx
+func (ctx *RenderContext) AddCancel(fn func()) {
+	if ctx == nil {
+		return
+	}
+	oldCancelFn := ctx.cancelFn
+	if oldCancelFn == nil {
+		ctx.cancelFn = fn
+		return
+	}
+	ctx.cancelFn = func() {
+		defer oldCancelFn()
+		fn()
+	}
 }
 
 // Renderer defines an interface for rendering markup file to HTML

routers/web/org/home.go

@@ -41,6 +41,7 @@ func Home(ctx *context.Context) {
 		desc, err := markdown.RenderString(&markup.RenderContext{
 			URLPrefix: ctx.Repo.RepoLink,
 			Metas:     map[string]string{"mode": "document"},
+			GitRepo:   ctx.Repo.GitRepo,
 		}, org.Description)
 		if err != nil {
 			ctx.ServerError("RenderString", err)

routers/web/repo/issue.go

@@ -1137,6 +1137,7 @@ func ViewIssue(ctx *context.Context) {
 	issue.RenderedContent, err = markdown.RenderString(&markup.RenderContext{
 		URLPrefix: ctx.Repo.RepoLink,
 		Metas:     ctx.Repo.Repository.ComposeMetas(),
+		GitRepo:   ctx.Repo.GitRepo,
 	}, issue.Content)
 	if err != nil {
 		ctx.ServerError("RenderString", err)
@@ -1301,6 +1302,7 @@ func ViewIssue(ctx *context.Context) {
 			comment.RenderedContent, err = markdown.RenderString(&markup.RenderContext{
 				URLPrefix: ctx.Repo.RepoLink,
 				Metas:     ctx.Repo.Repository.ComposeMetas(),
+				GitRepo:   ctx.Repo.GitRepo,
 			}, comment.Content)
 			if err != nil {
 				ctx.ServerError("RenderString", err)
@@ -1376,6 +1378,7 @@ func ViewIssue(ctx *context.Context) {
 			comment.RenderedContent, err = markdown.RenderString(&markup.RenderContext{
 				URLPrefix: ctx.Repo.RepoLink,
 				Metas:     ctx.Repo.Repository.ComposeMetas(),
+				GitRepo:   ctx.Repo.GitRepo,
 			}, comment.Content)
 			if err != nil {
 				ctx.ServerError("RenderString", err)
@@ -1734,6 +1737,7 @@ func UpdateIssueContent(ctx *context.Context) {
 	content, err := markdown.RenderString(&markup.RenderContext{
 		URLPrefix: ctx.Query("context"),
 		Metas:     ctx.Repo.Repository.ComposeMetas(),
+		GitRepo:   ctx.Repo.GitRepo,
 	}, issue.Content)
 	if err != nil {
 		ctx.ServerError("RenderString", err)
@@ -2161,6 +2165,7 @@ func UpdateCommentContent(ctx *context.Context) {
 	content, err := markdown.RenderString(&markup.RenderContext{
 		URLPrefix: ctx.Query("context"),
 		Metas:     ctx.Repo.Repository.ComposeMetas(),
+		GitRepo:   ctx.Repo.GitRepo,
 	}, comment.Content)
 	if err != nil {
 		ctx.ServerError("RenderString", err)

routers/web/repo/milestone.go

@@ -88,6 +88,7 @@ func Milestones(ctx *context.Context) {
 		m.RenderedContent, err = markdown.RenderString(&markup.RenderContext{
 			URLPrefix: ctx.Repo.RepoLink,
 			Metas:     ctx.Repo.Repository.ComposeMetas(),
+			GitRepo:   ctx.Repo.GitRepo,
 		}, m.Content)
 		if err != nil {
 			ctx.ServerError("RenderString", err)
@@ -280,6 +281,7 @@ func MilestoneIssuesAndPulls(ctx *context.Context) {
 	milestone.RenderedContent, err = markdown.RenderString(&markup.RenderContext{
 		URLPrefix: ctx.Repo.RepoLink,
 		Metas:     ctx.Repo.Repository.ComposeMetas(),
+		GitRepo:   ctx.Repo.GitRepo,
 	}, milestone.Content)
 	if err != nil {
 		ctx.ServerError("RenderString", err)

routers/web/repo/projects.go

@@ -81,6 +81,7 @@ func Projects(ctx *context.Context) {
 		projects[i].RenderedContent, err = markdown.RenderString(&markup.RenderContext{
 			URLPrefix: ctx.Repo.RepoLink,
 			Metas:     ctx.Repo.Repository.ComposeMetas(),
+			GitRepo:   ctx.Repo.GitRepo,
 		}, projects[i].Description)
 		if err != nil {
 			ctx.ServerError("RenderString", err)
@@ -322,6 +323,7 @@ func ViewProject(ctx *context.Context) {
 	project.RenderedContent, err = markdown.RenderString(&markup.RenderContext{
 		URLPrefix: ctx.Repo.RepoLink,
 		Metas:     ctx.Repo.Repository.ComposeMetas(),
+		GitRepo:   ctx.Repo.GitRepo,
 	}, project.Description)
 	if err != nil {
 		ctx.ServerError("RenderString", err)

routers/web/repo/release.go

@@ -145,6 +145,7 @@ func releasesOrTags(ctx *context.Context, isTagList bool) {
 		r.Note, err = markdown.RenderString(&markup.RenderContext{
 			URLPrefix: ctx.Repo.RepoLink,
 			Metas:     ctx.Repo.Repository.ComposeMetas(),
+			GitRepo:   ctx.Repo.GitRepo,
 		}, r.Note)
 		if err != nil {
 			ctx.ServerError("RenderString", err)
@@ -213,6 +214,7 @@ func SingleRelease(ctx *context.Context) {
 	release.Note, err = markdown.RenderString(&markup.RenderContext{
 		URLPrefix: ctx.Repo.RepoLink,
 		Metas:     ctx.Repo.Repository.ComposeMetas(),
+		GitRepo:   ctx.Repo.GitRepo,
 	}, release.Note)
 	if err != nil {
 		ctx.ServerError("RenderString", err)

routers/web/repo/view.go

@@ -338,6 +338,7 @@ func renderDirectory(ctx *context.Context, treeLink string) {
 						Filename:  readmeFile.name,
 						URLPrefix: readmeTreelink,
 						Metas:     ctx.Repo.Repository.ComposeDocumentMetas(),
+						GitRepo:   ctx.Repo.GitRepo,
 					}, rd, &result)
 					if err != nil {
 						log.Error("Render failed: %v then fallback", err)
@@ -512,6 +513,7 @@ func renderFile(ctx *context.Context, entry *git.TreeEntry, treeLink, rawLink st
 				Filename:  blob.Name(),
 				URLPrefix: path.Dir(treeLink),
 				Metas:     ctx.Repo.Repository.ComposeDocumentMetas(),
+				GitRepo:   ctx.Repo.GitRepo,
 			}, rd, &result)
 			if err != nil {
 				ctx.ServerError("Render", err)
@@ -570,6 +572,7 @@ func renderFile(ctx *context.Context, entry *git.TreeEntry, treeLink, rawLink st
 				Filename:  blob.Name(),
 				URLPrefix: path.Dir(treeLink),
 				Metas:     ctx.Repo.Repository.ComposeDocumentMetas(),
+				GitRepo:   ctx.Repo.GitRepo,
 			}, rd, &result)
 			if err != nil {
 				ctx.ServerError("Render", err)

routers/web/user/profile.go

@@ -117,6 +117,7 @@ func Profile(ctx *context.Context) {
 		content, err := markdown.RenderString(&markup.RenderContext{
 			URLPrefix: ctx.Repo.RepoLink,
 			Metas:     map[string]string{"mode": "document"},
+			GitRepo:   ctx.Repo.GitRepo,
 		}, ctxUser.Description)
 		if err != nil {
 			ctx.ServerError("RenderString", err)