Use gitrepo.GetTreePathLatestCommit to get file lastest commit instead from latest commit cache (#32987)

The latest commit cache is currently used only for listing tree files.
However, a cold start may take longer than directly invoking the Git
command. This PR addresses the issue of slow response times when
accessing raw files, improving performance in such scenarios.

```log
gitea.log:105521:2024/12/23 08:22:18 ...eb/routing/logger.go:68:func1() [W] router: slow      GET /xxxx/xxxxxx/raw/commit/xxxxxxxxxxxxxxxxxxxxxxxxxxx/.editorconfig for 172.18.0.5:53252, elapsed 3526.8ms @ repo/download.go:117(repo.SingleDownload)
```

modules/git/tree.go

@@ -62,3 +62,14 @@ func (repo *Repository) LsTree(ref string, filenames ...string) ([]string, error
 
 	return filelist, err
 }
+
+// GetTreePathLatestCommitID returns the latest commit of a tree path
+func (repo *Repository) GetTreePathLatestCommit(refName, treePath string) (*Commit, error) {
+	stdout, _, err := NewCommand(repo.Ctx, "rev-list", "-1").
+		AddDynamicArguments(refName).AddDashesAndList(treePath).
+		RunStdString(&RunOpts{Dir: repo.Path})
+	if err != nil {
+		return nil, err
+	}
+	return repo.GetCommit(strings.TrimSpace(stdout))
+}

modules/git/tree_test.go

@@ -25,3 +25,18 @@ func TestSubTree_Issue29101(t *testing.T) {
 		assert.True(t, IsErrNotExist(err))
 	}
 }
+
+func Test_GetTreePathLatestCommit(t *testing.T) {
+	repo, err := openRepositoryWithDefaultContext(filepath.Join(testReposDir, "repo6_blame"))
+	assert.NoError(t, err)
+	defer repo.Close()
+
+	commitID, err := repo.GetBranchCommitID("master")
+	assert.NoError(t, err)
+	assert.EqualValues(t, "544d8f7a3b15927cddf2299b4b562d6ebd71b6a7", commitID)
+
+	commit, err := repo.GetTreePathLatestCommit("master", "blame.txt")
+	assert.NoError(t, err)
+	assert.NotNil(t, commit)
+	assert.EqualValues(t, "45fb6cbc12f970b04eacd5cd4165edd11c8d7376", commit.ID.String())
+}

routers/api/v1/repo/file.go

@@ -11,7 +11,6 @@ import (
 	"fmt"
 	"io"
 	"net/http"
-	"path"
 	"strings"
 	"time"
 
@@ -242,19 +241,14 @@ func getBlobForEntry(ctx *context.APIContext) (blob *git.Blob, entry *git.TreeEn
 		return nil, nil, nil
 	}
 
-	info, _, err := git.Entries([]*git.TreeEntry{entry}).GetCommitsInfo(ctx, ctx.Repo.Commit, path.Dir("/" + ctx.Repo.TreePath)[1:])
+	latestCommit, err := ctx.Repo.GitRepo.GetTreePathLatestCommit(ctx.Repo.Commit.ID.String(), ctx.Repo.TreePath)
 	if err != nil {
-		ctx.Error(http.StatusInternalServerError, "GetCommitsInfo", err)
+		ctx.Error(http.StatusInternalServerError, "GetTreePathLatestCommit", err)
 		return nil, nil, nil
 	}
+	when := &latestCommit.Committer.When
 
-	if len(info) == 1 {
+	return entry.Blob(), entry, when
-		// Not Modified
-		lastModified = &info[0].Commit.Committer.When
-	}
-	blob = entry.Blob()
-
-	return blob, entry, lastModified
 }
 
 // GetArchive get archive of a repository

routers/web/repo/download.go

@@ -5,7 +5,6 @@
 package repo
 
 import (
-	"path"
 	"time"
 
 	git_model "code.gitea.io/gitea/models/git"
@@ -82,7 +81,7 @@ func ServeBlobOrLFS(ctx *context.Context, blob *git.Blob, lastModified *time.Tim
 	return common.ServeBlob(ctx.Base, ctx.Repo.TreePath, blob, lastModified)
 }
 
-func getBlobForEntry(ctx *context.Context) (blob *git.Blob, lastModified *time.Time) {
+func getBlobForEntry(ctx *context.Context) (*git.Blob, *time.Time) {
 	entry, err := ctx.Repo.Commit.GetTreeEntryByPath(ctx.Repo.TreePath)
 	if err != nil {
 		if git.IsErrNotExist(err) {
@@ -98,19 +97,14 @@ func getBlobForEntry(ctx *context.Context) (blob *git.Blob, lastModified *time.T
 		return nil, nil
 	}
 
-	info, _, err := git.Entries([]*git.TreeEntry{entry}).GetCommitsInfo(ctx, ctx.Repo.Commit, path.Dir("/" + ctx.Repo.TreePath)[1:])
+	latestCommit, err := ctx.Repo.GitRepo.GetTreePathLatestCommit(ctx.Repo.Commit.ID.String(), ctx.Repo.TreePath)
 	if err != nil {
-		ctx.ServerError("GetCommitsInfo", err)
+		ctx.ServerError("GetTreePathLatestCommit", err)
 		return nil, nil
 	}
+	lastModified := &latestCommit.Committer.When
 
-	if len(info) == 1 {
+	return entry.Blob(), lastModified
-		// Not Modified
-		lastModified = &info[0].Commit.Committer.When
-	}
-	blob = entry.Blob()
-
-	return blob, lastModified
 }
 
 // SingleDownload download a file by repos path