Reduce calls to git cat-file -s (#14682)

* Reduce calls to git cat-file -s

There are multiple places where there are repeated calls to git cat-file
-s due to the blobs not being created with their size.

Through judicious use of git ls-tree -l and slight adjustments to the
indexer code we can avoid a lot of these calls.

* simplify by always expecting the long format

* Also always set the sized field and tell the indexer the update is sized

modules/indexer/code/bleve.go

@@ -179,14 +179,20 @@ func (b *BleveIndexer) addUpdate(commitSha string, update fileUpdate, repo *mode
 		return nil
 	}
 
-	stdout, err := git.NewCommand("cat-file", "-s", update.BlobSha).
-		RunInDir(repo.RepoPath())
-	if err != nil {
-		return err
+	size := update.Size
+
+	if !update.Sized {
+		stdout, err := git.NewCommand("cat-file", "-s", update.BlobSha).
+			RunInDir(repo.RepoPath())
+		if err != nil {
+			return err
+		}
+		if size, err = strconv.ParseInt(strings.TrimSpace(stdout), 10, 64); err != nil {
+			return fmt.Errorf("Misformatted git cat-file output: %v", err)
+		}
 	}
-	if size, err := strconv.Atoi(strings.TrimSpace(stdout)); err != nil {
-		return fmt.Errorf("Misformatted git cat-file output: %v", err)
-	} else if int64(size) > setting.Indexer.MaxIndexerFileSize {
+
+	if size > setting.Indexer.MaxIndexerFileSize {
 		return b.addDelete(update.Filename, repo, batch)
 	}