Refactor code indexer (#9313)

* Refactor code indexer

* fix test

* fix test

* refactor code indexer

* fix import

* improve code

* fix typo

* fix test and make code clean

* fix lint

7 files changed, 765 insertions, 625 deletions

diff --git a/modules/indexer/code/bleve.go b/modules/indexer/code/bleve.go
index bb2fc5bc74..339dca74a1 100644
--- a/modules/indexer/code/bleve.go
+++ b/modules/indexer/code/bleve.go
@@ -9,182 +9,90 @@ import (
 	"os"
 	"strconv"
 	"strings"
-	"time"
 
 	"code.gitea.io/gitea/models"
 	"code.gitea.io/gitea/modules/base"
 	"code.gitea.io/gitea/modules/charset"
 	"code.gitea.io/gitea/modules/git"
-	"code.gitea.io/gitea/modules/graceful"
 	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
+
+	"github.com/blevesearch/bleve"
+	"github.com/blevesearch/bleve/analysis/analyzer/custom"
+	"github.com/blevesearch/bleve/analysis/token/lowercase"
+	"github.com/blevesearch/bleve/analysis/token/unicodenorm"
+	"github.com/blevesearch/bleve/analysis/tokenizer/unicode"
+	"github.com/blevesearch/bleve/index/upsidedown"
+	"github.com/blevesearch/bleve/mapping"
+	"github.com/blevesearch/bleve/search/query"
 	"github.com/ethantkoenig/rupture"
 )
 
-type repoIndexerOperation struct {
-	repoID   int64
-	deleted  bool
-	watchers []chan<- error
-}
-
-var repoIndexerOperationQueue chan repoIndexerOperation
+const unicodeNormalizeName = "unicodeNormalize"
+const maxBatchSize = 16
 
-// InitRepoIndexer initialize the repo indexer
-func InitRepoIndexer() {
-	if !setting.Indexer.RepoIndexerEnabled {
-		return
-	}
-	waitChannel := make(chan time.Duration)
-	// FIXME: graceful: This should use a persistable queue
-	repoIndexerOperationQueue = make(chan repoIndexerOperation, setting.Indexer.UpdateQueueLength)
-	go func() {
-		start := time.Now()
-		log.Info("PID: %d: Initializing Repository Indexer", os.Getpid())
-		initRepoIndexer(populateRepoIndexerAsynchronously)
-		go processRepoIndexerOperationQueue()
-		waitChannel <- time.Since(start)
-	}()
-	if setting.Indexer.StartupTimeout > 0 {
-		go func() {
-			timeout := setting.Indexer.StartupTimeout
-			if graceful.GetManager().IsChild() && setting.GracefulHammerTime > 0 {
-				timeout += setting.GracefulHammerTime
-			}
-			select {
-			case duration := <-waitChannel:
-				log.Info("Repository Indexer Initialization took %v", duration)
-			case <-time.After(timeout):
-				log.Fatal("Repository Indexer Initialization Timed-Out after: %v", timeout)
-			}
-		}()
-
-	}
+// indexerID a bleve-compatible unique identifier for an integer id
+func indexerID(id int64) string {
+	return strconv.FormatInt(id, 36)
 }
 
-// populateRepoIndexerAsynchronously asynchronously populates the repo indexer
-// with pre-existing data. This should only be run when the indexer is created
-// for the first time.
-func populateRepoIndexerAsynchronously() error {
-	exist, err := models.IsTableNotEmpty("repository")
-	if err != nil {
-		return err
-	} else if !exist {
-		return nil
-	}
-
-	var maxRepoID int64
-	if maxRepoID, err = models.GetMaxID("repository"); err != nil {
-		return err
-	}
-	go populateRepoIndexer(maxRepoID)
-	return nil
+// numericEqualityQuery a numeric equality query for the given value and field
+func numericEqualityQuery(value int64, field string) *query.NumericRangeQuery {
+	f := float64(value)
+	tru := true
+	q := bleve.NewNumericRangeInclusiveQuery(&f, &f, &tru, &tru)
+	q.SetField(field)
+	return q
 }
 
-// populateRepoIndexer populate the repo indexer with pre-existing data. This
-// should only be run when the indexer is created for the first time.
-// FIXME: graceful: This should use a persistable queue
-func populateRepoIndexer(maxRepoID int64) {
-	log.Info("Populating the repo indexer with existing repositories")
-
-	isShutdown := graceful.GetManager().IsShutdown()
-
-	// start with the maximum existing repo ID and work backwards, so that we
-	// don't include repos that are created after gitea starts; such repos will
-	// already be added to the indexer, and we don't need to add them again.
-	for maxRepoID > 0 {
-		select {
-		case <-isShutdown:
-			log.Info("Repository Indexer population shutdown before completion")
-			return
-		default:
-		}
-		ids, err := models.GetUnindexedRepos(maxRepoID, 0, 50)
-		if err != nil {
-			log.Error("populateRepoIndexer: %v", err)
-			return
-		} else if len(ids) == 0 {
-			break
-		}
-		for _, id := range ids {
-			select {
-			case <-isShutdown:
-				log.Info("Repository Indexer population shutdown before completion")
-				return
-			default:
-			}
-			repoIndexerOperationQueue <- repoIndexerOperation{
-				repoID:  id,
-				deleted: false,
-			}
-			maxRepoID = id - 1
-		}
-	}
-	log.Info("Done (re)populating the repo indexer with existing repositories")
+func addUnicodeNormalizeTokenFilter(m *mapping.IndexMappingImpl) error {
+	return m.AddCustomTokenFilter(unicodeNormalizeName, map[string]interface{}{
+		"type": unicodenorm.Name,
+		"form": unicodenorm.NFC,
+	})
 }
 
-func updateRepoIndexer(repoID int64) error {
-	repo, err := models.GetRepositoryByID(repoID)
-	if err != nil {
-		return fmt.Errorf("UpdateRepoIndexer: Unable to GetRepositoryByID: %d, Error: %v", repoID, err)
+// openIndexer open the index at the specified path, checking for metadata
+// updates and bleve version updates.  If index needs to be created (or
+// re-created), returns (nil, nil)
+func openIndexer(path string, latestVersion int) (bleve.Index, error) {
+	_, err := os.Stat(path)
+	if err != nil && os.IsNotExist(err) {
+		return nil, nil
+	} else if err != nil {
+		return nil, err
 	}
 
-	sha, err := getDefaultBranchSha(repo)
+	metadata, err := rupture.ReadIndexMetadata(path)
 	if err != nil {
-		return fmt.Errorf("UpdateRepoIndexer: Unable to GetDefaultBranchSha for: %s/%s, Error: %v", repo.MustOwnerName(), repo.Name, err)
+		return nil, err
 	}
-	changes, err := getRepoChanges(repo, sha)
-	if err != nil {
-		return fmt.Errorf("UpdateRepoIndexer: Unable to GetRepoChanges for: %s/%s Sha: %s Error: %v", repo.MustOwnerName(), repo.Name, sha, err)
-	} else if changes == nil {
-		return nil
+	if metadata.Version < latestVersion {
+		// the indexer is using a previous version, so we should delete it and
+		// re-populate
+		return nil, os.RemoveAll(path)
 	}
 
-	batch := RepoIndexerBatch()
-	for _, update := range changes.Updates {
-		if err := addUpdate(update, repo, batch); err != nil {
-			return fmt.Errorf("UpdateRepoIndexer: Unable to addUpdate to: %s/%s Sha: %s, update: %s(%s) Error: %v", repo.MustOwnerName(), repo.Name, sha, update.Filename, update.BlobSha, err)
-		}
-	}
-	for _, filename := range changes.RemovedFilenames {
-		if err := addDelete(filename, repo, batch); err != nil {
-			return fmt.Errorf("UpdateRepoIndexer: Unable to addDelete to: %s/%s Sha: %s, filename: %s Error: %v", repo.MustOwnerName(), repo.Name, sha, filename, err)
-		}
-	}
-	if err = batch.Flush(); err != nil {
-		return fmt.Errorf("UpdateRepoIndexer: Unable to flush batch to indexer for repo: %s/%s Error: %v", repo.MustOwnerName(), repo.Name, err)
+	index, err := bleve.Open(path)
+	if err != nil && err == upsidedown.IncompatibleVersion {
+		// the indexer was built with a previous version of bleve, so we should
+		// delete it and re-populate
+		return nil, os.RemoveAll(path)
+	} else if err != nil {
+		return nil, err
 	}
-	return repo.UpdateIndexerStatus(sha)
+	return index, nil
 }
 
-// repoChanges changes (file additions/updates/removals) to a repo
-type repoChanges struct {
-	Updates          []fileUpdate
-	RemovedFilenames []string
+// RepoIndexerData data stored in the repo indexer
+type RepoIndexerData struct {
+	RepoID  int64
+	Content string
 }
 
-type fileUpdate struct {
-	Filename string
-	BlobSha  string
-}
-
-func getDefaultBranchSha(repo *models.Repository) (string, error) {
-	stdout, err := git.NewCommand("show-ref", "-s", git.BranchPrefix+repo.DefaultBranch).RunInDir(repo.RepoPath())
-	if err != nil {
-		return "", err
-	}
-	return strings.TrimSpace(stdout), nil
-}
-
-// getRepoChanges returns changes to repo since last indexer update
-func getRepoChanges(repo *models.Repository, revision string) (*repoChanges, error) {
-	if err := repo.GetIndexerStatus(); err != nil {
-		return nil, err
-	}
-
-	if len(repo.IndexerStatus.CommitSha) == 0 {
-		return genesisChanges(repo, revision)
-	}
-	return nonGenesisChanges(repo, revision)
+// Type returns the document type, for bleve's mapping.Classifier interface.
+func (d *RepoIndexerData) Type() string {
+	return repoIndexerDocType
 }
 
 func addUpdate(update fileUpdate, repo *models.Repository, batch rupture.FlushingBatch) error {
@@ -207,174 +115,231 @@ func addUpdate(update fileUpdate, repo *models.Repository, batch rupture.Flushin
 		// FIXME: UTF-16 files will probably fail here
 		return nil
 	}
-	indexerUpdate := RepoIndexerUpdate{
-		Filepath: update.Filename,
-		Op:       RepoIndexerOpUpdate,
-		Data: &RepoIndexerData{
-			RepoID:  repo.ID,
-			Content: string(charset.ToUTF8DropErrors(fileContents)),
-		},
-	}
-	return indexerUpdate.AddToFlushingBatch(batch)
+
+	id := filenameIndexerID(repo.ID, update.Filename)
+	return batch.Index(id, &RepoIndexerData{
+		RepoID:  repo.ID,
+		Content: string(charset.ToUTF8DropErrors(fileContents)),
+	})
 }
 
 func addDelete(filename string, repo *models.Repository, batch rupture.FlushingBatch) error {
-	indexerUpdate := RepoIndexerUpdate{
-		Filepath: filename,
-		Op:       RepoIndexerOpDelete,
-		Data: &RepoIndexerData{
-			RepoID: repo.ID,
-		},
-	}
-	return indexerUpdate.AddToFlushingBatch(batch)
+	id := filenameIndexerID(repo.ID, filename)
+	return batch.Delete(id)
 }
 
-func isIndexable(entry *git.TreeEntry) bool {
-	if !entry.IsRegular() && !entry.IsExecutable() {
-		return false
+const (
+	repoIndexerAnalyzer      = "repoIndexerAnalyzer"
+	repoIndexerDocType       = "repoIndexerDocType"
+	repoIndexerLatestVersion = 4
+)
+
+// createRepoIndexer create a repo indexer if one does not already exist
+func createRepoIndexer(path string, latestVersion int) (bleve.Index, error) {
+	docMapping := bleve.NewDocumentMapping()
+	numericFieldMapping := bleve.NewNumericFieldMapping()
+	numericFieldMapping.IncludeInAll = false
+	docMapping.AddFieldMappingsAt("RepoID", numericFieldMapping)
+
+	textFieldMapping := bleve.NewTextFieldMapping()
+	textFieldMapping.IncludeInAll = false
+	docMapping.AddFieldMappingsAt("Content", textFieldMapping)
+
+	mapping := bleve.NewIndexMapping()
+	if err := addUnicodeNormalizeTokenFilter(mapping); err != nil {
+		return nil, err
+	} else if err := mapping.AddCustomAnalyzer(repoIndexerAnalyzer, map[string]interface{}{
+		"type":          custom.Name,
+		"char_filters":  []string{},
+		"tokenizer":     unicode.Name,
+		"token_filters": []string{unicodeNormalizeName, lowercase.Name},
+	}); err != nil {
+		return nil, err
 	}
-	name := strings.ToLower(entry.Name())
-	for _, g := range setting.Indexer.ExcludePatterns {
-		if g.Match(name) {
-			return false
-		}
+	mapping.DefaultAnalyzer = repoIndexerAnalyzer
+	mapping.AddDocumentMapping(repoIndexerDocType, docMapping)
+	mapping.AddDocumentMapping("_all", bleve.NewDocumentDisabledMapping())
+
+	indexer, err := bleve.New(path, mapping)
+	if err != nil {
+		return nil, err
 	}
-	for _, g := range setting.Indexer.IncludePatterns {
-		if g.Match(name) {
-			return true
-		}
+
+	if err = rupture.WriteIndexMetadata(path, &rupture.IndexMetadata{
+		Version: latestVersion,
+	}); err != nil {
+		return nil, err
 	}
-	return len(setting.Indexer.IncludePatterns) == 0
+	return indexer, nil
+}
+
+func filenameIndexerID(repoID int64, filename string) string {
+	return indexerID(repoID) + "_" + filename
 }
 
-// parseGitLsTreeOutput parses the output of a `git ls-tree -r --full-name` command
-func parseGitLsTreeOutput(stdout []byte) ([]fileUpdate, error) {
-	entries, err := git.ParseTreeEntries(stdout)
+func filenameOfIndexerID(indexerID string) string {
+	index := strings.IndexByte(indexerID, '_')
+	if index == -1 {
+		log.Error("Unexpected ID in repo indexer: %s", indexerID)
+	}
+	return indexerID[index+1:]
+}
+
+var (
+	_ Indexer = &BleveIndexer{}
+)
+
+// BleveIndexer represents a bleve indexer implementation
+type BleveIndexer struct {
+	indexDir string
+	indexer  bleve.Index
+}
+
+// NewBleveIndexer creates a new bleve local indexer
+func NewBleveIndexer(indexDir string) (*BleveIndexer, bool, error) {
+	indexer := &BleveIndexer{
+		indexDir: indexDir,
+	}
+	created, err := indexer.init()
+	return indexer, created, err
+}
+
+// init init the indexer
+func (b *BleveIndexer) init() (bool, error) {
+	var err error
+	b.indexer, err = openIndexer(b.indexDir, repoIndexerLatestVersion)
 	if err != nil {
-		return nil, err
+		return false, err
 	}
-	var idxCount = 0
-	updates := make([]fileUpdate, len(entries))
-	for _, entry := range entries {
-		if isIndexable(entry) {
-			updates[idxCount] = fileUpdate{
-				Filename: entry.Name(),
-				BlobSha:  entry.ID.String(),
-			}
-			idxCount++
+	if b.indexer != nil {
+		return false, nil
+	}
+
+	b.indexer, err = createRepoIndexer(b.indexDir, repoIndexerLatestVersion)
+	if err != nil {
+		return false, err
+	}
+
+	return true, nil
+}
+
+// Close close the indexer
+func (b *BleveIndexer) Close() {
+	log.Debug("Closing repo indexer")
+	if b.indexer != nil {
+		err := b.indexer.Close()
+		if err != nil {
+			log.Error("Error whilst closing the repository indexer: %v", err)
 		}
 	}
-	return updates[:idxCount], nil
+	log.Info("PID: %d Repository Indexer closed", os.Getpid())
 }
 
-// genesisChanges get changes to add repo to the indexer for the first time
-func genesisChanges(repo *models.Repository, revision string) (*repoChanges, error) {
-	var changes repoChanges
-	stdout, err := git.NewCommand("ls-tree", "--full-tree", "-r", revision).
-		RunInDirBytes(repo.RepoPath())
+// Index indexes the data
+func (b *BleveIndexer) Index(repoID int64) error {
+	repo, err := models.GetRepositoryByID(repoID)
 	if err != nil {
-		return nil, err
+		return err
 	}
-	changes.Updates, err = parseGitLsTreeOutput(stdout)
-	return &changes, err
-}
 
-// nonGenesisChanges get changes since the previous indexer update
-func nonGenesisChanges(repo *models.Repository, revision string) (*repoChanges, error) {
-	diffCmd := git.NewCommand("diff", "--name-status",
-		repo.IndexerStatus.CommitSha, revision)
-	stdout, err := diffCmd.RunInDir(repo.RepoPath())
+	sha, err := getDefaultBranchSha(repo)
 	if err != nil {
-		// previous commit sha may have been removed by a force push, so
-		// try rebuilding from scratch
-		log.Warn("git diff: %v", err)
-		if err = deleteRepoFromIndexer(repo.ID); err != nil {
-			return nil, err
-		}
-		return genesisChanges(repo, revision)
+		return err
+	}
+	changes, err := getRepoChanges(repo, sha)
+	if err != nil {
+		return err
+	} else if changes == nil {
+		return nil
 	}
-	var changes repoChanges
-	updatedFilenames := make([]string, 0, 10)
-	for _, line := range strings.Split(stdout, "\n") {
-		line = strings.TrimSpace(line)
-		if len(line) == 0 {
-			continue
-		}
-		filename := strings.TrimSpace(line[1:])
-		if len(filename) == 0 {
-			continue
-		} else if filename[0] == '"' {
-			filename, err = strconv.Unquote(filename)
-			if err != nil {
-				return nil, err
-			}
-		}
 
-		switch status := line[0]; status {
-		case 'M', 'A':
-			updatedFilenames = append(updatedFilenames, filename)
-		case 'D':
-			changes.RemovedFilenames = append(changes.RemovedFilenames, filename)
-		default:
-			log.Warn("Unrecognized status: %c (line=%s)", status, line)
+	batch := rupture.NewFlushingBatch(b.indexer, maxBatchSize)
+	for _, update := range changes.Updates {
+		if err := addUpdate(update, repo, batch); err != nil {
+			return err
 		}
 	}
+	for _, filename := range changes.RemovedFilenames {
+		if err := addDelete(filename, repo, batch); err != nil {
+			return err
+		}
+	}
+	if err = batch.Flush(); err != nil {
+		return err
+	}
+	return repo.UpdateIndexerStatus(sha)
+}
 
-	cmd := git.NewCommand("ls-tree", "--full-tree", revision, "--")
-	cmd.AddArguments(updatedFilenames...)
-	lsTreeStdout, err := cmd.RunInDirBytes(repo.RepoPath())
+// Delete deletes indexes by ids
+func (b *BleveIndexer) Delete(repoID int64) error {
+	query := numericEqualityQuery(repoID, "RepoID")
+	searchRequest := bleve.NewSearchRequestOptions(query, 2147483647, 0, false)
+	result, err := b.indexer.Search(searchRequest)
 	if err != nil {
-		return nil, err
+		return err
+	}
+	batch := rupture.NewFlushingBatch(b.indexer, maxBatchSize)
+	for _, hit := range result.Hits {
+		if err = batch.Delete(hit.ID); err != nil {
+			return err
+		}
 	}
-	changes.Updates, err = parseGitLsTreeOutput(lsTreeStdout)
-	return &changes, err
+	return batch.Flush()
 }
 
-func processRepoIndexerOperationQueue() {
-	for {
-		select {
-		case op := <-repoIndexerOperationQueue:
-			var err error
-			if op.deleted {
-				if err = deleteRepoFromIndexer(op.repoID); err != nil {
-					log.Error("DeleteRepoFromIndexer: %v", err)
-				}
-			} else {
-				if err = updateRepoIndexer(op.repoID); err != nil {
-					log.Error("updateRepoIndexer: %v", err)
-				}
-			}
-			for _, watcher := range op.watchers {
-				watcher <- err
-			}
-		case <-graceful.GetManager().IsShutdown():
-			log.Info("PID: %d Repository indexer queue processing stopped", os.Getpid())
-			return
+// Search searches for files in the specified repo.
+// Returns the matching file-paths
+func (b *BleveIndexer) Search(repoIDs []int64, keyword string, page, pageSize int) (int64, []*SearchResult, error) {
+	phraseQuery := bleve.NewMatchPhraseQuery(keyword)
+	phraseQuery.FieldVal = "Content"
+	phraseQuery.Analyzer = repoIndexerAnalyzer
+
+	var indexerQuery query.Query
+	if len(repoIDs) > 0 {
+		var repoQueries = make([]query.Query, 0, len(repoIDs))
+		for _, repoID := range repoIDs {
+			repoQueries = append(repoQueries, numericEqualityQuery(repoID, "RepoID"))
 		}
 
+		indexerQuery = bleve.NewConjunctionQuery(
+			bleve.NewDisjunctionQuery(repoQueries...),
+			phraseQuery,
+		)
+	} else {
+		indexerQuery = phraseQuery
 	}
-}
-
-// DeleteRepoFromIndexer remove all of a repository's entries from the indexer
-func DeleteRepoFromIndexer(repo *models.Repository, watchers ...chan<- error) {
-	addOperationToQueue(repoIndexerOperation{repoID: repo.ID, deleted: true, watchers: watchers})
-}
 
-// UpdateRepoIndexer update a repository's entries in the indexer
-func UpdateRepoIndexer(repo *models.Repository, watchers ...chan<- error) {
-	addOperationToQueue(repoIndexerOperation{repoID: repo.ID, deleted: false, watchers: watchers})
-}
+	from := (page - 1) * pageSize
+	searchRequest := bleve.NewSearchRequestOptions(indexerQuery, pageSize, from, false)
+	searchRequest.Fields = []string{"Content", "RepoID"}
+	searchRequest.IncludeLocations = true
 
-func addOperationToQueue(op repoIndexerOperation) {
-	if !setting.Indexer.RepoIndexerEnabled {
-		return
+	result, err := b.indexer.Search(searchRequest)
+	if err != nil {
+		return 0, nil, err
 	}
-	select {
-	case repoIndexerOperationQueue <- op:
-		break
-	default:
-		go func() {
-			repoIndexerOperationQueue <- op
-		}()
+
+	searchResults := make([]*SearchResult, len(result.Hits))
+	for i, hit := range result.Hits {
+		var startIndex, endIndex int = -1, -1
+		for _, locations := range hit.Locations["Content"] {
+			location := locations[0]
+			locationStart := int(location.Start)
+			locationEnd := int(location.End)
+			if startIndex < 0 || locationStart < startIndex {
+				startIndex = locationStart
+			}
+			if endIndex < 0 || locationEnd > endIndex {
+				endIndex = locationEnd
+			}
+		}
+		searchResults[i] = &SearchResult{
+			RepoID:     int64(hit.Fields["RepoID"].(float64)),
+			StartIndex: startIndex,
+			EndIndex:   endIndex,
+			Filename:   filenameOfIndexerID(hit.ID),
+			Content:    hit.Fields["Content"].(string),
+		}
 	}
+	return int64(result.Total), searchResults, nil
 }
diff --git a/modules/indexer/code/bleve_test.go b/modules/indexer/code/bleve_test.go
index 2eafeef3c5..ac2b411998 100644
--- a/modules/indexer/code/bleve_test.go
+++ b/modules/indexer/code/bleve_test.go
@@ -5,12 +5,66 @@
 package code
 
 import (
+	"os"
 	"path/filepath"
 	"testing"
 
 	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+
+	"github.com/stretchr/testify/assert"
 )
 
 func TestMain(m *testing.M) {
 	models.MainTest(m, filepath.Join("..", "..", ".."))
 }
+
+func TestIndexAndSearch(t *testing.T) {
+	models.PrepareTestEnv(t)
+
+	dir := "./bleve.index"
+	os.RemoveAll(dir)
+
+	setting.Indexer.RepoIndexerEnabled = true
+	idx, _, err := NewBleveIndexer(dir)
+	if err != nil {
+		idx.Close()
+		log.Fatal("indexer.Init: %v", err)
+	}
+
+	err = idx.Index(1)
+	assert.NoError(t, err)
+
+	var (
+		keywords = []struct {
+			Keyword string
+			IDs     []int64
+		}{
+			{
+				Keyword: "Description",
+				IDs:     []int64{1},
+			},
+			{
+				Keyword: "repo1",
+				IDs:     []int64{1},
+			},
+			{
+				Keyword: "non-exist",
+				IDs:     []int64{},
+			},
+		}
+	)
+
+	for _, kw := range keywords {
+		total, res, err := idx.Search(nil, kw.Keyword, 1, 10)
+		assert.NoError(t, err)
+		assert.EqualValues(t, len(kw.IDs), total)
+
+		var ids = make([]int64, 0, len(res))
+		for _, hit := range res {
+			ids = append(ids, hit.RepoID)
+		}
+		assert.EqualValues(t, kw.IDs, ids)
+	}
+}
diff --git a/modules/indexer/code/git.go b/modules/indexer/code/git.go
new file mode 100644
index 0000000000..bfa7d20438
--- /dev/null
+++ b/modules/indexer/code/git.go
@@ -0,0 +1,147 @@
+// Copyright 2019 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 code
+
+import (
+	"strconv"
+	"strings"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/git"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+)
+
+type fileUpdate struct {
+	Filename string
+	BlobSha  string
+}
+
+// repoChanges changes (file additions/updates/removals) to a repo
+type repoChanges struct {
+	Updates          []fileUpdate
+	RemovedFilenames []string
+}
+
+func getDefaultBranchSha(repo *models.Repository) (string, error) {
+	stdout, err := git.NewCommand("show-ref", "-s", git.BranchPrefix+repo.DefaultBranch).RunInDir(repo.RepoPath())
+	if err != nil {
+		return "", err
+	}
+	return strings.TrimSpace(stdout), nil
+}
+
+// getRepoChanges returns changes to repo since last indexer update
+func getRepoChanges(repo *models.Repository, revision string) (*repoChanges, error) {
+	if err := repo.GetIndexerStatus(); err != nil {
+		return nil, err
+	}
+
+	if len(repo.IndexerStatus.CommitSha) == 0 {
+		return genesisChanges(repo, revision)
+	}
+	return nonGenesisChanges(repo, revision)
+}
+
+func isIndexable(entry *git.TreeEntry) bool {
+	if !entry.IsRegular() && !entry.IsExecutable() {
+		return false
+	}
+	name := strings.ToLower(entry.Name())
+	for _, g := range setting.Indexer.ExcludePatterns {
+		if g.Match(name) {
+			return false
+		}
+	}
+	for _, g := range setting.Indexer.IncludePatterns {
+		if g.Match(name) {
+			return true
+		}
+	}
+	return len(setting.Indexer.IncludePatterns) == 0
+}
+
+// parseGitLsTreeOutput parses the output of a `git ls-tree -r --full-name` command
+func parseGitLsTreeOutput(stdout []byte) ([]fileUpdate, error) {
+	entries, err := git.ParseTreeEntries(stdout)
+	if err != nil {
+		return nil, err
+	}
+	var idxCount = 0
+	updates := make([]fileUpdate, len(entries))
+	for _, entry := range entries {
+		if isIndexable(entry) {
+			updates[idxCount] = fileUpdate{
+				Filename: entry.Name(),
+				BlobSha:  entry.ID.String(),
+			}
+			idxCount++
+		}
+	}
+	return updates[:idxCount], nil
+}
+
+// genesisChanges get changes to add repo to the indexer for the first time
+func genesisChanges(repo *models.Repository, revision string) (*repoChanges, error) {
+	var changes repoChanges
+	stdout, err := git.NewCommand("ls-tree", "--full-tree", "-r", revision).
+		RunInDirBytes(repo.RepoPath())
+	if err != nil {
+		return nil, err
+	}
+	changes.Updates, err = parseGitLsTreeOutput(stdout)
+	return &changes, err
+}
+
+// nonGenesisChanges get changes since the previous indexer update
+func nonGenesisChanges(repo *models.Repository, revision string) (*repoChanges, error) {
+	diffCmd := git.NewCommand("diff", "--name-status",
+		repo.IndexerStatus.CommitSha, revision)
+	stdout, err := diffCmd.RunInDir(repo.RepoPath())
+	if err != nil {
+		// previous commit sha may have been removed by a force push, so
+		// try rebuilding from scratch
+		log.Warn("git diff: %v", err)
+		if err = indexer.Delete(repo.ID); err != nil {
+			return nil, err
+		}
+		return genesisChanges(repo, revision)
+	}
+	var changes repoChanges
+	updatedFilenames := make([]string, 0, 10)
+	for _, line := range strings.Split(stdout, "\n") {
+		line = strings.TrimSpace(line)
+		if len(line) == 0 {
+			continue
+		}
+		filename := strings.TrimSpace(line[1:])
+		if len(filename) == 0 {
+			continue
+		} else if filename[0] == '"' {
+			filename, err = strconv.Unquote(filename)
+			if err != nil {
+				return nil, err
+			}
+		}
+
+		switch status := line[0]; status {
+		case 'M', 'A':
+			updatedFilenames = append(updatedFilenames, filename)
+		case 'D':
+			changes.RemovedFilenames = append(changes.RemovedFilenames, filename)
+		default:
+			log.Warn("Unrecognized status: %c (line=%s)", status, line)
+		}
+	}
+
+	cmd := git.NewCommand("ls-tree", "--full-tree", revision, "--")
+	cmd.AddArguments(updatedFilenames...)
+	lsTreeStdout, err := cmd.RunInDirBytes(repo.RepoPath())
+	if err != nil {
+		return nil, err
+	}
+	changes.Updates, err = parseGitLsTreeOutput(lsTreeStdout)
+	return &changes, err
+}
diff --git a/modules/indexer/code/indexer.go b/modules/indexer/code/indexer.go
index 3907a7b57d..c68c7c2d71 100644
--- a/modules/indexer/code/indexer.go
+++ b/modules/indexer/code/indexer.go
@@ -5,72 +5,73 @@
 package code
 
 import (
-	"os"
-	"strconv"
+	"time"
 
+	"code.gitea.io/gitea/modules/graceful"
+	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
+)
 
-	"github.com/blevesearch/bleve"
-	"github.com/blevesearch/bleve/analysis/token/unicodenorm"
-	"github.com/blevesearch/bleve/index/upsidedown"
-	"github.com/blevesearch/bleve/mapping"
-	"github.com/blevesearch/bleve/search/query"
-	"github.com/ethantkoenig/rupture"
+var (
+	indexer Indexer
 )
 
-// indexerID a bleve-compatible unique identifier for an integer id
-func indexerID(id int64) string {
-	return strconv.FormatInt(id, 36)
+// SearchResult result of performing a search in a repo
+type SearchResult struct {
+	RepoID     int64
+	StartIndex int
+	EndIndex   int
+	Filename   string
+	Content    string
 }
 
-// numericEqualityQuery a numeric equality query for the given value and field
-func numericEqualityQuery(value int64, field string) *query.NumericRangeQuery {
-	f := float64(value)
-	tru := true
-	q := bleve.NewNumericRangeInclusiveQuery(&f, &f, &tru, &tru)
-	q.SetField(field)
-	return q
+// Indexer defines an interface to indexer issues contents
+type Indexer interface {
+	Index(repoID int64) error
+	Delete(repoID int64) error
+	Search(repoIDs []int64, keyword string, page, pageSize int) (int64, []*SearchResult, error)
+	Close()
 }
 
-const unicodeNormalizeName = "unicodeNormalize"
+// Init initialize the repo indexer
+func Init() {
+	if !setting.Indexer.RepoIndexerEnabled {
+		return
+	}
 
-func addUnicodeNormalizeTokenFilter(m *mapping.IndexMappingImpl) error {
-	return m.AddCustomTokenFilter(unicodeNormalizeName, map[string]interface{}{
-		"type": unicodenorm.Name,
-		"form": unicodenorm.NFC,
-	})
-}
+	waitChannel := make(chan time.Duration)
+	go func() {
+		start := time.Now()
+		log.Info("Initializing Repository Indexer")
+		var created bool
+		var err error
+		indexer, created, err = NewBleveIndexer(setting.Indexer.RepoPath)
+		if err != nil {
+			indexer.Close()
+			log.Fatal("indexer.Init: %v", err)
+		}
 
-const maxBatchSize = 16
+		go processRepoIndexerOperationQueue(indexer)
 
-// openIndexer open the index at the specified path, checking for metadata
-// updates and bleve version updates.  If index needs to be created (or
-// re-created), returns (nil, nil)
-func openIndexer(path string, latestVersion int) (bleve.Index, error) {
-	_, err := os.Stat(setting.Indexer.IssuePath)
-	if err != nil && os.IsNotExist(err) {
-		return nil, nil
-	} else if err != nil {
-		return nil, err
-	}
+		if created {
+			go populateRepoIndexer()
+		}
 
-	metadata, err := rupture.ReadIndexMetadata(path)
-	if err != nil {
-		return nil, err
-	}
-	if metadata.Version < latestVersion {
-		// the indexer is using a previous version, so we should delete it and
-		// re-populate
-		return nil, os.RemoveAll(path)
-	}
+		waitChannel <- time.Since(start)
+	}()
 
-	index, err := bleve.Open(path)
-	if err != nil && err == upsidedown.IncompatibleVersion {
-		// the indexer was built with a previous version of bleve, so we should
-		// delete it and re-populate
-		return nil, os.RemoveAll(path)
-	} else if err != nil {
-		return nil, err
+	if setting.Indexer.StartupTimeout > 0 {
+		go func() {
+			timeout := setting.Indexer.StartupTimeout
+			if graceful.GetManager().IsChild() && setting.GracefulHammerTime > 0 {
+				timeout += setting.GracefulHammerTime
+			}
+			select {
+			case duration := <-waitChannel:
+				log.Info("Repository Indexer Initialization took %v", duration)
+			case <-time.After(timeout):
+				log.Fatal("Repository Indexer Initialization Timed-Out after: %v", timeout)
+			}
+		}()
 	}
-	return index, nil
 }
diff --git a/modules/indexer/code/queue.go b/modules/indexer/code/queue.go
new file mode 100644
index 0000000000..90f7d1bb19
--- /dev/null
+++ b/modules/indexer/code/queue.go
@@ -0,0 +1,133 @@
+// Copyright 2019 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 code
+
+import (
+	"os"
+
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/graceful"
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/setting"
+)
+
+type repoIndexerOperation struct {
+	repoID   int64
+	deleted  bool
+	watchers []chan<- error
+}
+
+var repoIndexerOperationQueue chan repoIndexerOperation
+
+func processRepoIndexerOperationQueue(indexer Indexer) {
+	defer indexer.Close()
+
+	repoIndexerOperationQueue = make(chan repoIndexerOperation, setting.Indexer.UpdateQueueLength)
+	for {
+		select {
+		case op := <-repoIndexerOperationQueue:
+			var err error
+			if op.deleted {
+				if err = indexer.Delete(op.repoID); err != nil {
+					log.Error("indexer.Delete: %v", err)
+				}
+			} else {
+				if err = indexer.Index(op.repoID); err != nil {
+					log.Error("indexer.Index: %v", err)
+				}
+			}
+			for _, watcher := range op.watchers {
+				watcher <- err
+			}
+		case <-graceful.GetManager().IsShutdown():
+			log.Info("PID: %d Repository indexer queue processing stopped", os.Getpid())
+			return
+		}
+	}
+}
+
+// DeleteRepoFromIndexer remove all of a repository's entries from the indexer
+func DeleteRepoFromIndexer(repo *models.Repository, watchers ...chan<- error) {
+	addOperationToQueue(repoIndexerOperation{repoID: repo.ID, deleted: true, watchers: watchers})
+}
+
+// UpdateRepoIndexer update a repository's entries in the indexer
+func UpdateRepoIndexer(repo *models.Repository, watchers ...chan<- error) {
+	addOperationToQueue(repoIndexerOperation{repoID: repo.ID, deleted: false, watchers: watchers})
+}
+
+func addOperationToQueue(op repoIndexerOperation) {
+	if !setting.Indexer.RepoIndexerEnabled {
+		return
+	}
+	select {
+	case repoIndexerOperationQueue <- op:
+		break
+	default:
+		go func() {
+			repoIndexerOperationQueue <- op
+		}()
+	}
+}
+
+// populateRepoIndexer populate the repo indexer with pre-existing data. This
+// should only be run when the indexer is created for the first time.
+func populateRepoIndexer() {
+	log.Info("Populating the repo indexer with existing repositories")
+
+	isShutdown := graceful.GetManager().IsShutdown()
+
+	exist, err := models.IsTableNotEmpty("repository")
+	if err != nil {
+		log.Fatal("System error: %v", err)
+	} else if !exist {
+		return
+	}
+
+	// if there is any existing repo indexer metadata in the DB, delete it
+	// since we are starting afresh. Also, xorm requires deletes to have a
+	// condition, and we want to delete everything, thus 1=1.
+	if err := models.DeleteAllRecords("repo_indexer_status"); err != nil {
+		log.Fatal("System error: %v", err)
+	}
+
+	var maxRepoID int64
+	if maxRepoID, err = models.GetMaxID("repository"); err != nil {
+		log.Fatal("System error: %v", err)
+	}
+
+	// start with the maximum existing repo ID and work backwards, so that we
+	// don't include repos that are created after gitea starts; such repos will
+	// already be added to the indexer, and we don't need to add them again.
+	for maxRepoID > 0 {
+		select {
+		case <-isShutdown:
+			log.Info("Repository Indexer population shutdown before completion")
+			return
+		default:
+		}
+		ids, err := models.GetUnindexedRepos(maxRepoID, 0, 50)
+		if err != nil {
+			log.Error("populateRepoIndexer: %v", err)
+			return
+		} else if len(ids) == 0 {
+			break
+		}
+		for _, id := range ids {
+			select {
+			case <-isShutdown:
+				log.Info("Repository Indexer population shutdown before completion")
+				return
+			default:
+			}
+			repoIndexerOperationQueue <- repoIndexerOperation{
+				repoID:  id,
+				deleted: false,
+			}
+			maxRepoID = id - 1
+		}
+	}
+	log.Info("Done (re)populating the repo indexer with existing repositories")
+}
diff --git a/modules/indexer/code/repo.go b/modules/indexer/code/repo.go
deleted file mode 100644
index bc5f317b7d..0000000000
--- a/modules/indexer/code/repo.go
+++ /dev/null
@@ -1,290 +0,0 @@
-// Copyright 2017 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 code
-
-import (
-	"context"
-	"os"
-	"strings"
-	"sync"
-
-	"code.gitea.io/gitea/models"
-	"code.gitea.io/gitea/modules/graceful"
-	"code.gitea.io/gitea/modules/log"
-	"code.gitea.io/gitea/modules/setting"
-
-	"github.com/blevesearch/bleve"
-	"github.com/blevesearch/bleve/analysis/analyzer/custom"
-	"github.com/blevesearch/bleve/analysis/token/lowercase"
-	"github.com/blevesearch/bleve/analysis/tokenizer/unicode"
-	"github.com/blevesearch/bleve/search/query"
-	"github.com/ethantkoenig/rupture"
-)
-
-const (
-	repoIndexerAnalyzer = "repoIndexerAnalyzer"
-	repoIndexerDocType  = "repoIndexerDocType"
-
-	repoIndexerLatestVersion = 4
-)
-
-type bleveIndexerHolder struct {
-	index bleve.Index
-	mutex sync.RWMutex
-	cond  *sync.Cond
-}
-
-func newBleveIndexerHolder() *bleveIndexerHolder {
-	b := &bleveIndexerHolder{}
-	b.cond = sync.NewCond(b.mutex.RLocker())
-	return b
-}
-
-func (r *bleveIndexerHolder) set(index bleve.Index) {
-	r.mutex.Lock()
-	defer r.mutex.Unlock()
-	r.index = index
-	r.cond.Broadcast()
-}
-
-func (r *bleveIndexerHolder) get() bleve.Index {
-	r.mutex.RLock()
-	defer r.mutex.RUnlock()
-	if r.index == nil {
-		r.cond.Wait()
-	}
-	return r.index
-}
-
-// repoIndexer (thread-safe) index for repository contents
-var indexerHolder = newBleveIndexerHolder()
-
-// RepoIndexerOp type of operation to perform on repo indexer
-type RepoIndexerOp int
-
-const (
-	// RepoIndexerOpUpdate add/update a file's contents
-	RepoIndexerOpUpdate = iota
-
-	// RepoIndexerOpDelete delete a file
-	RepoIndexerOpDelete
-)
-
-// RepoIndexerData data stored in the repo indexer
-type RepoIndexerData struct {
-	RepoID  int64
-	Content string
-}
-
-// Type returns the document type, for bleve's mapping.Classifier interface.
-func (d *RepoIndexerData) Type() string {
-	return repoIndexerDocType
-}
-
-// RepoIndexerUpdate an update to the repo indexer
-type RepoIndexerUpdate struct {
-	Filepath string
-	Op       RepoIndexerOp
-	Data     *RepoIndexerData
-}
-
-// AddToFlushingBatch adds the update to the given flushing batch.
-func (update RepoIndexerUpdate) AddToFlushingBatch(batch rupture.FlushingBatch) error {
-	id := filenameIndexerID(update.Data.RepoID, update.Filepath)
-	switch update.Op {
-	case RepoIndexerOpUpdate:
-		return batch.Index(id, update.Data)
-	case RepoIndexerOpDelete:
-		return batch.Delete(id)
-	default:
-		log.Error("Unrecognized repo indexer op: %d", update.Op)
-	}
-	return nil
-}
-
-// initRepoIndexer initialize repo indexer
-func initRepoIndexer(populateIndexer func() error) {
-	indexer, err := openIndexer(setting.Indexer.RepoPath, repoIndexerLatestVersion)
-	if err != nil {
-		log.Fatal("InitRepoIndexer %s: %v", setting.Indexer.RepoPath, err)
-	}
-	if indexer != nil {
-		indexerHolder.set(indexer)
-		closeAtTerminate()
-
-		// Continue population from where left off
-		if err = populateIndexer(); err != nil {
-			log.Fatal("PopulateRepoIndex: %v", err)
-		}
-		return
-	}
-
-	if err = createRepoIndexer(setting.Indexer.RepoPath, repoIndexerLatestVersion); err != nil {
-		log.Fatal("CreateRepoIndexer: %v", err)
-	}
-	closeAtTerminate()
-
-	// if there is any existing repo indexer metadata in the DB, delete it
-	// since we are starting afresh. Also, xorm requires deletes to have a
-	// condition, and we want to delete everything, thus 1=1.
-	if err := models.DeleteAllRecords("repo_indexer_status"); err != nil {
-		log.Fatal("DeleteAllRepoIndexerStatus: %v", err)
-	}
-
-	if err = populateIndexer(); err != nil {
-		log.Fatal("PopulateRepoIndex: %v", err)
-	}
-}
-
-func closeAtTerminate() {
-	graceful.GetManager().RunAtTerminate(context.Background(), func() {
-		log.Debug("Closing repo indexer")
-		indexer := indexerHolder.get()
-		if indexer != nil {
-			err := indexer.Close()
-			if err != nil {
-				log.Error("Error whilst closing the repository indexer: %v", err)
-			}
-		}
-		log.Info("PID: %d Repository Indexer closed", os.Getpid())
-	})
-}
-
-// createRepoIndexer create a repo indexer if one does not already exist
-func createRepoIndexer(path string, latestVersion int) error {
-	docMapping := bleve.NewDocumentMapping()
-	numericFieldMapping := bleve.NewNumericFieldMapping()
-	numericFieldMapping.IncludeInAll = false
-	docMapping.AddFieldMappingsAt("RepoID", numericFieldMapping)
-
-	textFieldMapping := bleve.NewTextFieldMapping()
-	textFieldMapping.IncludeInAll = false
-	docMapping.AddFieldMappingsAt("Content", textFieldMapping)
-
-	mapping := bleve.NewIndexMapping()
-	if err := addUnicodeNormalizeTokenFilter(mapping); err != nil {
-		return err
-	} else if err := mapping.AddCustomAnalyzer(repoIndexerAnalyzer, map[string]interface{}{
-		"type":          custom.Name,
-		"char_filters":  []string{},
-		"tokenizer":     unicode.Name,
-		"token_filters": []string{unicodeNormalizeName, lowercase.Name},
-	}); err != nil {
-		return err
-	}
-	mapping.DefaultAnalyzer = repoIndexerAnalyzer
-	mapping.AddDocumentMapping(repoIndexerDocType, docMapping)
-	mapping.AddDocumentMapping("_all", bleve.NewDocumentDisabledMapping())
-
-	indexer, err := bleve.New(path, mapping)
-	if err != nil {
-		return err
-	}
-	indexerHolder.set(indexer)
-
-	return rupture.WriteIndexMetadata(path, &rupture.IndexMetadata{
-		Version: latestVersion,
-	})
-}
-
-func filenameIndexerID(repoID int64, filename string) string {
-	return indexerID(repoID) + "_" + filename
-}
-
-func filenameOfIndexerID(indexerID string) string {
-	index := strings.IndexByte(indexerID, '_')
-	if index == -1 {
-		log.Error("Unexpected ID in repo indexer: %s", indexerID)
-	}
-	return indexerID[index+1:]
-}
-
-// RepoIndexerBatch batch to add updates to
-func RepoIndexerBatch() rupture.FlushingBatch {
-	return rupture.NewFlushingBatch(indexerHolder.get(), maxBatchSize)
-}
-
-// deleteRepoFromIndexer delete all of a repo's files from indexer
-func deleteRepoFromIndexer(repoID int64) error {
-	query := numericEqualityQuery(repoID, "RepoID")
-	searchRequest := bleve.NewSearchRequestOptions(query, 2147483647, 0, false)
-	result, err := indexerHolder.get().Search(searchRequest)
-	if err != nil {
-		return err
-	}
-	batch := RepoIndexerBatch()
-	for _, hit := range result.Hits {
-		if err = batch.Delete(hit.ID); err != nil {
-			return err
-		}
-	}
-	return batch.Flush()
-}
-
-// RepoSearchResult result of performing a search in a repo
-type RepoSearchResult struct {
-	RepoID     int64
-	StartIndex int
-	EndIndex   int
-	Filename   string
-	Content    string
-}
-
-// SearchRepoByKeyword searches for files in the specified repo.
-// Returns the matching file-paths
-func SearchRepoByKeyword(repoIDs []int64, keyword string, page, pageSize int) (int64, []*RepoSearchResult, error) {
-	phraseQuery := bleve.NewMatchPhraseQuery(keyword)
-	phraseQuery.FieldVal = "Content"
-	phraseQuery.Analyzer = repoIndexerAnalyzer
-
-	var indexerQuery query.Query
-	if len(repoIDs) > 0 {
-		var repoQueries = make([]query.Query, 0, len(repoIDs))
-		for _, repoID := range repoIDs {
-			repoQueries = append(repoQueries, numericEqualityQuery(repoID, "RepoID"))
-		}
-
-		indexerQuery = bleve.NewConjunctionQuery(
-			bleve.NewDisjunctionQuery(repoQueries...),
-			phraseQuery,
-		)
-	} else {
-		indexerQuery = phraseQuery
-	}
-
-	from := (page - 1) * pageSize
-	searchRequest := bleve.NewSearchRequestOptions(indexerQuery, pageSize, from, false)
-	searchRequest.Fields = []string{"Content", "RepoID"}
-	searchRequest.IncludeLocations = true
-
-	result, err := indexerHolder.get().Search(searchRequest)
-	if err != nil {
-		return 0, nil, err
-	}
-
-	searchResults := make([]*RepoSearchResult, len(result.Hits))
-	for i, hit := range result.Hits {
-		var startIndex, endIndex int = -1, -1
-		for _, locations := range hit.Locations["Content"] {
-			location := locations[0]
-			locationStart := int(location.Start)
-			locationEnd := int(location.End)
-			if startIndex < 0 || locationStart < startIndex {
-				startIndex = locationStart
-			}
-			if endIndex < 0 || locationEnd > endIndex {
-				endIndex = locationEnd
-			}
-		}
-		searchResults[i] = &RepoSearchResult{
-			RepoID:     int64(hit.Fields["RepoID"].(float64)),
-			StartIndex: startIndex,
-			EndIndex:   endIndex,
-			Filename:   filenameOfIndexerID(hit.ID),
-			Content:    hit.Fields["Content"].(string),
-		}
-	}
-	return int64(result.Total), searchResults, nil
-}
diff --git a/modules/indexer/code/search.go b/modules/indexer/code/search.go
new file mode 100644
index 0000000000..18f193a532
--- /dev/null
+++ b/modules/indexer/code/search.go
@@ -0,0 +1,130 @@
+// Copyright 2017 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 code
+
+import (
+	"bytes"
+	"html"
+	gotemplate "html/template"
+	"strings"
+
+	"code.gitea.io/gitea/modules/highlight"
+	"code.gitea.io/gitea/modules/util"
+)
+
+// Result a search result to display
+type Result struct {
+	RepoID         int64
+	Filename       string
+	HighlightClass string
+	LineNumbers    []int
+	FormattedLines gotemplate.HTML
+}
+
+func indices(content string, selectionStartIndex, selectionEndIndex int) (int, int) {
+	startIndex := selectionStartIndex
+	numLinesBefore := 0
+	for ; startIndex > 0; startIndex-- {
+		if content[startIndex-1] == '\n' {
+			if numLinesBefore == 1 {
+				break
+			}
+			numLinesBefore++
+		}
+	}
+
+	endIndex := selectionEndIndex
+	numLinesAfter := 0
+	for ; endIndex < len(content); endIndex++ {
+		if content[endIndex] == '\n' {
+			if numLinesAfter == 1 {
+				break
+			}
+			numLinesAfter++
+		}
+	}
+
+	return startIndex, endIndex
+}
+
+func writeStrings(buf *bytes.Buffer, strs ...string) error {
+	for _, s := range strs {
+		_, err := buf.WriteString(s)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func searchResult(result *SearchResult, startIndex, endIndex int) (*Result, error) {
+	startLineNum := 1 + strings.Count(result.Content[:startIndex], "\n")
+
+	var formattedLinesBuffer bytes.Buffer
+
+	contentLines := strings.SplitAfter(result.Content[startIndex:endIndex], "\n")
+	lineNumbers := make([]int, len(contentLines))
+	index := startIndex
+	for i, line := range contentLines {
+		var err error
+		if index < result.EndIndex &&
+			result.StartIndex < index+len(line) &&
+			result.StartIndex < result.EndIndex {
+			openActiveIndex := util.Max(result.StartIndex-index, 0)
+			closeActiveIndex := util.Min(result.EndIndex-index, len(line))
+			err = writeStrings(&formattedLinesBuffer,
+				`<li>`,
+				html.EscapeString(line[:openActiveIndex]),
+				`<span class='active'>`,
+				html.EscapeString(line[openActiveIndex:closeActiveIndex]),
+				`</span>`,
+				html.EscapeString(line[closeActiveIndex:]),
+				`</li>`,
+			)
+		} else {
+			err = writeStrings(&formattedLinesBuffer,
+				`<li>`,
+				html.EscapeString(line),
+				`</li>`,
+			)
+		}
+		if err != nil {
+			return nil, err
+		}
+
+		lineNumbers[i] = startLineNum + i
+		index += len(line)
+	}
+	return &Result{
+		RepoID:         result.RepoID,
+		Filename:       result.Filename,
+		HighlightClass: highlight.FileNameToHighlightClass(result.Filename),
+		LineNumbers:    lineNumbers,
+		FormattedLines: gotemplate.HTML(formattedLinesBuffer.String()),
+	}, nil
+}
+
+// PerformSearch perform a search on a repository
+func PerformSearch(repoIDs []int64, keyword string, page, pageSize int) (int, []*Result, error) {
+	if len(keyword) == 0 {
+		return 0, nil, nil
+	}
+
+	total, results, err := indexer.Search(repoIDs, keyword, page, pageSize)
+	if err != nil {
+		return 0, nil, err
+	}
+
+	displayResults := make([]*Result, len(results))
+
+	for i, result := range results {
+		startIndex, endIndex := indices(result.Content, result.StartIndex, result.EndIndex)
+		displayResults[i], err = searchResult(result, startIndex, endIndex)
+		if err != nil {
+			return 0, nil, err
+		}
+	}
+	return int(total), displayResults, nil
+}