Language statistics bar for repositories (#8037)

* Implementation for calculating language statistics

Impement saving code language statistics to database

Implement rendering langauge stats

Add primary laguage to show in repository list

Implement repository stats indexer queue

Add indexer test

Refactor to use queue module

* Do not timeout for queues

modules/indexer/stats/db.go

@@ -0,0 +1,54 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package stats
+
+import (
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/git"
+)
+
+// DBIndexer implements Indexer interface to use database's like search
+type DBIndexer struct {
+}
+
+// Index repository status function
+func (db *DBIndexer) Index(id int64) error {
+	repo, err := models.GetRepositoryByID(id)
+	if err != nil {
+		return err
+	}
+	status, err := repo.GetIndexerStatus(models.RepoIndexerTypeStats)
+	if err != nil {
+		return err
+	}
+
+	gitRepo, err := git.OpenRepository(repo.RepoPath())
+	if err != nil {
+		return err
+	}
+	defer gitRepo.Close()
+
+	// Get latest commit for default branch
+	commitID, err := gitRepo.GetBranchCommitID(repo.DefaultBranch)
+	if err != nil {
+		return err
+	}
+
+	// Do not recalculate stats if already calculated for this commit
+	if status.CommitSha == commitID {
+		return nil
+	}
+
+	// Calculate and save language statistics to database
+	stats, err := gitRepo.GetLanguageStats(commitID)
+	if err != nil {
+		return err
+	}
+	return repo.UpdateLanguageStats(commitID, stats)
+}
+
+// Close dummy function
+func (db *DBIndexer) Close() {
+}