Add latest commit's SHA to content response (#20398)

* Add latest commit's SHA to content response

- When requesting the contents of a filepath, add the latest commit's
SHA to the requested file.
- Resolves #12840

* Add swagger

* Fix NPE

* Fix tests

* Hook into LastCommitCache

* Move AddLastCommitCache to a common nogogit and gogit file

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Prevent NPE

Co-authored-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

services/repository/files/content.go

@@ -165,13 +165,24 @@ func GetContents(ctx context.Context, repo *repo_model.Repository, treePath, ref
 	}
 	selfURLString := selfURL.String()
 
+	err = gitRepo.AddLastCommitCache(repo.GetCommitsCountCacheKey(ref, refType != git.ObjectCommit), repo.FullName(), commitID)
+	if err != nil {
+		return nil, err
+	}
+
+	lastCommit, err := commit.GetCommitByPath(treePath)
+	if err != nil {
+		return nil, err
+	}
+
 	// All content types have these fields in populated
 	contentsResponse := &api.ContentsResponse{
-		Name: entry.Name(),
-		Path: treePath,
-		SHA:  entry.ID.String(),
-		Size: entry.Size(),
-		URL:  &selfURLString,
+		Name:          entry.Name(),
+		Path:          treePath,
+		SHA:           entry.ID.String(),
+		LastCommitSHA: lastCommit.ID.String(),
+		Size:          entry.Size(),
+		URL:           &selfURLString,
 		Links: &api.FileLinksResponse{
 			Self: &selfURLString,
 		},

services/repository/files/content_test.go

@@ -33,17 +33,18 @@ func getExpectedReadmeContentsResponse() *api.ContentsResponse {
 	gitURL := "https://try.gitea.io/api/v1/repos/user2/repo1/git/blobs/" + sha
 	downloadURL := "https://try.gitea.io/user2/repo1/raw/branch/master/" + treePath
 	return &api.ContentsResponse{
-		Name:        treePath,
-		Path:        treePath,
-		SHA:         "4b4851ad51df6a7d9f25c979345979eaeb5b349f",
-		Type:        "file",
-		Size:        30,
-		Encoding:    &encoding,
-		Content:     &content,
-		URL:         &selfURL,
-		HTMLURL:     &htmlURL,
-		GitURL:      &gitURL,
-		DownloadURL: &downloadURL,
+		Name:          treePath,
+		Path:          treePath,
+		SHA:           "4b4851ad51df6a7d9f25c979345979eaeb5b349f",
+		LastCommitSHA: "65f1bf27bc3bf70f64657658635e66094edbcb4d",
+		Type:          "file",
+		Size:          30,
+		Encoding:      &encoding,
+		Content:       &content,
+		URL:           &selfURL,
+		HTMLURL:       &htmlURL,
+		GitURL:        &gitURL,
+		DownloadURL:   &downloadURL,
 		Links: &api.FileLinksResponse{
 			Self:    &selfURL,
 			GitURL:  &gitURL,

services/repository/files/file_test.go

@@ -43,17 +43,18 @@ func getExpectedFileResponse() *api.FileResponse {
 	downloadURL := setting.AppURL + "user2/repo1/raw/branch/master/" + treePath
 	return &api.FileResponse{
 		Content: &api.ContentsResponse{
-			Name:        treePath,
-			Path:        treePath,
-			SHA:         sha,
-			Type:        "file",
-			Size:        30,
-			Encoding:    &encoding,
-			Content:     &content,
-			URL:         &selfURL,
-			HTMLURL:     &htmlURL,
-			GitURL:      &gitURL,
-			DownloadURL: &downloadURL,
+			Name:          treePath,
+			Path:          treePath,
+			SHA:           sha,
+			LastCommitSHA: "65f1bf27bc3bf70f64657658635e66094edbcb4d",
+			Type:          "file",
+			Size:          30,
+			Encoding:      &encoding,
+			Content:       &content,
+			URL:           &selfURL,
+			HTMLURL:       &htmlURL,
+			GitURL:        &gitURL,
+			DownloadURL:   &downloadURL,
 			Links: &api.FileLinksResponse{
 				Self:    &selfURL,
 				GitURL:  &gitURL,