6 files changed, 347 insertions, 0 deletions
diff --git a/modules/indexer/internal/bleve/batch.go b/modules/indexer/internal/bleve/batch.go
new file mode 100644
index 00000000..ed5ef077
--- /dev/null
+++ b/modules/indexer/internal/bleve/batch.go
@@ -0,0 +1,58 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package bleve
+
+import (
+	"github.com/blevesearch/bleve/v2"
+)
+
+// FlushingBatch is a batch of operations that automatically flushes to the
+// underlying index once it reaches a certain size.
+type FlushingBatch struct {
+	maxBatchSize int
+	batch        *bleve.Batch
+	index        bleve.Index
+}
+
+// NewFlushingBatch creates a new flushing batch for the specified index. Once
+// the number of operations in the batch reaches the specified limit, the batch
+// automatically flushes its operations to the index.
+func NewFlushingBatch(index bleve.Index, maxBatchSize int) *FlushingBatch {
+	return &FlushingBatch{
+		maxBatchSize: maxBatchSize,
+		batch:        index.NewBatch(),
+		index:        index,
+	}
+}
+
+// Index add a new index to batch
+func (b *FlushingBatch) Index(id string, data any) error {
+	if err := b.batch.Index(id, data); err != nil {
+		return err
+	}
+	return b.flushIfFull()
+}
+
+// Delete add a delete index to batch
+func (b *FlushingBatch) Delete(id string) error {
+	b.batch.Delete(id)
+	return b.flushIfFull()
+}
+
+func (b *FlushingBatch) flushIfFull() error {
+	if b.batch.Size() < b.maxBatchSize {
+		return nil
+	}
+	return b.Flush()
+}
+
+// Flush submit the batch and create a new one
+func (b *FlushingBatch) Flush() error {
+	err := b.index.Batch(b.batch)
+	if err != nil {
+		return err
+	}
+	b.batch = b.index.NewBatch()
+	return nil
+}
diff --git a/modules/indexer/internal/bleve/indexer.go b/modules/indexer/internal/bleve/indexer.go
new file mode 100644
index 00000000..1435d2f5
--- /dev/null
+++ b/modules/indexer/internal/bleve/indexer.go
@@ -0,0 +1,102 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package bleve
+
+import (
+	"context"
+	"fmt"
+
+	"code.gitea.io/gitea/modules/indexer/internal"
+	"code.gitea.io/gitea/modules/log"
+
+	"github.com/blevesearch/bleve/v2"
+	"github.com/blevesearch/bleve/v2/mapping"
+)
+
+var _ internal.Indexer = &Indexer{}
+
+// Indexer represents a basic bleve indexer implementation
+type Indexer struct {
+	Indexer bleve.Index
+
+	indexDir      string
+	version       int
+	mappingGetter MappingGetter
+}
+
+type MappingGetter func() (mapping.IndexMapping, error)
+
+func NewIndexer(indexDir string, version int, mappingGetter func() (mapping.IndexMapping, error)) *Indexer {
+	return &Indexer{
+		indexDir:      indexDir,
+		version:       version,
+		mappingGetter: mappingGetter,
+	}
+}
+
+// Init initializes the indexer
+func (i *Indexer) Init(_ context.Context) (bool, error) {
+	if i == nil {
+		return false, fmt.Errorf("cannot init nil indexer")
+	}
+
+	if i.Indexer != nil {
+		return false, fmt.Errorf("indexer is already initialized")
+	}
+
+	indexer, version, err := openIndexer(i.indexDir, i.version)
+	if err != nil {
+		return false, err
+	}
+	if indexer != nil {
+		i.Indexer = indexer
+		return true, nil
+	}
+
+	if version != 0 {
+		log.Warn("Found older bleve index with version %d, Forgejo will remove it and rebuild", version)
+	}
+
+	indexMapping, err := i.mappingGetter()
+	if err != nil {
+		return false, err
+	}
+
+	indexer, err = bleve.New(i.indexDir, indexMapping)
+	if err != nil {
+		return false, err
+	}
+
+	if err = writeIndexMetadata(i.indexDir, &IndexMetadata{
+		Version: i.version,
+	}); err != nil {
+		return false, err
+	}
+
+	i.Indexer = indexer
+
+	return false, nil
+}
+
+// Ping checks if the indexer is available
+func (i *Indexer) Ping(_ context.Context) error {
+	if i == nil {
+		return fmt.Errorf("cannot ping nil indexer")
+	}
+	if i.Indexer == nil {
+		return fmt.Errorf("indexer is not initialized")
+	}
+	return nil
+}
+
+func (i *Indexer) Close() {
+	if i == nil || i.Indexer == nil {
+		return
+	}
+
+	if err := i.Indexer.Close(); err != nil {
+		log.Error("Failed to close bleve indexer in %q: %v", i.indexDir, err)
+	}
+	i.Indexer = nil
+}
diff --git a/modules/indexer/internal/bleve/metadata.go b/modules/indexer/internal/bleve/metadata.go
new file mode 100644
index 00000000..3c570ab4
--- /dev/null
+++ b/modules/indexer/internal/bleve/metadata.go
@@ -0,0 +1,55 @@
+// Copyright 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+// Copied and modified from https://github.com/ethantkoenig/rupture (MIT License)
+
+package bleve
+
+import (
+	"os"
+	"path/filepath"
+
+	"code.gitea.io/gitea/modules/json"
+)
+
+const metaFilename = "rupture_meta.json"
+
+func indexMetadataPath(dir string) string {
+	return filepath.Join(dir, metaFilename)
+}
+
+// IndexMetadata contains metadata about a bleve index.
+type IndexMetadata struct {
+	// The version of the data in the index. This can be useful for tracking
+	// schema changes or data migrations.
+	Version int `json:"version"`
+}
+
+// readIndexMetadata returns the metadata for the index at the specified path.
+// If no such index metadata exists, an empty metadata and a nil error are
+// returned.
+func readIndexMetadata(path string) (*IndexMetadata, error) {
+	meta := &IndexMetadata{}
+	metaPath := indexMetadataPath(path)
+	if _, err := os.Stat(metaPath); os.IsNotExist(err) {
+		return meta, nil
+	} else if err != nil {
+		return nil, err
+	}
+
+	metaBytes, err := os.ReadFile(metaPath)
+	if err != nil {
+		return nil, err
+	}
+	return meta, json.Unmarshal(metaBytes, &meta)
+}
+
+// writeIndexMetadata writes metadata for the index at the specified path.
+func writeIndexMetadata(path string, meta *IndexMetadata) error {
+	metaBytes, err := json.Marshal(meta)
+	if err != nil {
+		return err
+	}
+
+	return os.WriteFile(indexMetadataPath(path), metaBytes, 0o644)
+}
diff --git a/modules/indexer/internal/bleve/metadata_test.go b/modules/indexer/internal/bleve/metadata_test.go
new file mode 100644
index 00000000..31603a92
--- /dev/null
+++ b/modules/indexer/internal/bleve/metadata_test.go
@@ -0,0 +1,28 @@
+// Copyright 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+// Copied and modified from https://github.com/ethantkoenig/rupture (MIT License)
+
+package bleve
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestMetadata(t *testing.T) {
+	dir := t.TempDir()
+
+	meta, err := readIndexMetadata(dir)
+	require.NoError(t, err)
+	assert.Equal(t, &IndexMetadata{}, meta)
+
+	meta.Version = 24
+	require.NoError(t, writeIndexMetadata(dir, meta))
+
+	meta, err = readIndexMetadata(dir)
+	require.NoError(t, err)
+	assert.EqualValues(t, 24, meta.Version)
+}
diff --git a/modules/indexer/internal/bleve/query.go b/modules/indexer/internal/bleve/query.go
new file mode 100644
index 00000000..21422b28
--- /dev/null
+++ b/modules/indexer/internal/bleve/query.go
@@ -0,0 +1,56 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package bleve
+
+import (
+	"code.gitea.io/gitea/modules/optional"
+
+	"github.com/blevesearch/bleve/v2"
+	"github.com/blevesearch/bleve/v2/search/query"
+)
+
+// NumericEqualityQuery generates 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
+}
+
+// MatchPhraseQuery generates a match phrase query for the given phrase, field and analyzer
+func MatchPhraseQuery(matchPhrase, field, analyzer string, fuzziness int) *query.MatchPhraseQuery {
+	q := bleve.NewMatchPhraseQuery(matchPhrase)
+	q.FieldVal = field
+	q.Analyzer = analyzer
+	q.Fuzziness = fuzziness
+	return q
+}
+
+// BoolFieldQuery generates a bool field query for the given value and field
+func BoolFieldQuery(value bool, field string) *query.BoolFieldQuery {
+	q := bleve.NewBoolFieldQuery(value)
+	q.SetField(field)
+	return q
+}
+
+func NumericRangeInclusiveQuery(min, max optional.Option[int64], field string) *query.NumericRangeQuery {
+	var minF, maxF *float64
+	var minI, maxI *bool
+	if min.Has() {
+		minF = new(float64)
+		*minF = float64(min.Value())
+		minI = new(bool)
+		*minI = true
+	}
+	if max.Has() {
+		maxF = new(float64)
+		*maxF = float64(max.Value())
+		maxI = new(bool)
+		*maxI = true
+	}
+	q := bleve.NewNumericRangeInclusiveQuery(minF, maxF, minI, maxI)
+	q.SetField(field)
+	return q
+}
diff --git a/modules/indexer/internal/bleve/util.go b/modules/indexer/internal/bleve/util.go
new file mode 100644
index 00000000..d05b6797
--- /dev/null
+++ b/modules/indexer/internal/bleve/util.go
@@ -0,0 +1,48 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package bleve
+
+import (
+	"errors"
+	"os"
+
+	"code.gitea.io/gitea/modules/log"
+	"code.gitea.io/gitea/modules/util"
+
+	"github.com/blevesearch/bleve/v2"
+	"github.com/blevesearch/bleve/v2/index/upsidedown"
+)
+
+// 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, int, error) {
+	_, err := os.Stat(path)
+	if err != nil && os.IsNotExist(err) {
+		return nil, 0, nil
+	} else if err != nil {
+		return nil, 0, err
+	}
+
+	metadata, err := readIndexMetadata(path)
+	if err != nil {
+		return nil, 0, err
+	}
+	if metadata.Version < latestVersion {
+		// the indexer is using a previous version, so we should delete it and
+		// re-populate
+		return nil, metadata.Version, util.RemoveAll(path)
+	}
+
+	index, err := bleve.Open(path)
+	if err != nil {
+		if errors.Is(err, upsidedown.IncompatibleVersion) {
+			log.Warn("Indexer was built with a previous version of bleve, deleting and rebuilding")
+			return nil, 0, util.RemoveAll(path)
+		}
+		return nil, 0, err
+	}
+
+	return index, 0, nil
+}