Adding upstream version 2.5.1.

Signed-off-by: Daniel Baumann <daniel@debian.org>

index/upsidedown/store/goleveldb/store.go

@@ -0,0 +1,152 @@
+//  Copyright (c) 2014 Couchbase, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 		http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package goleveldb
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+
+	"github.com/blevesearch/bleve/v2/registry"
+	"github.com/blevesearch/goleveldb/leveldb"
+	"github.com/blevesearch/goleveldb/leveldb/opt"
+	"github.com/blevesearch/goleveldb/leveldb/util"
+	store "github.com/blevesearch/upsidedown_store_api"
+)
+
+const (
+	Name                    = "goleveldb"
+	defaultCompactBatchSize = 250
+)
+
+type Store struct {
+	path string
+	opts *opt.Options
+	db   *leveldb.DB
+	mo   store.MergeOperator
+
+	defaultWriteOptions *opt.WriteOptions
+	defaultReadOptions  *opt.ReadOptions
+}
+
+func New(mo store.MergeOperator, config map[string]interface{}) (store.KVStore, error) {
+
+	path, ok := config["path"].(string)
+	if !ok {
+		return nil, fmt.Errorf("must specify path")
+	}
+	if path == "" {
+		return nil, os.ErrInvalid
+	}
+
+	opts, err := applyConfig(&opt.Options{}, config)
+	if err != nil {
+		return nil, err
+	}
+
+	db, err := leveldb.OpenFile(path, opts)
+	if err != nil {
+		return nil, err
+	}
+
+	rv := Store{
+		path:                path,
+		opts:                opts,
+		db:                  db,
+		mo:                  mo,
+		defaultReadOptions:  &opt.ReadOptions{},
+		defaultWriteOptions: &opt.WriteOptions{},
+	}
+	rv.defaultWriteOptions.Sync = true
+	return &rv, nil
+}
+
+func (ldbs *Store) Close() error {
+	return ldbs.db.Close()
+}
+
+func (ldbs *Store) Reader() (store.KVReader, error) {
+	snapshot, _ := ldbs.db.GetSnapshot()
+	return &Reader{
+		store:    ldbs,
+		snapshot: snapshot,
+	}, nil
+}
+
+func (ldbs *Store) Writer() (store.KVWriter, error) {
+	return &Writer{
+		store: ldbs,
+	}, nil
+}
+
+// CompactWithBatchSize removes DictionaryTerm entries with a count of zero (in batchSize batches), then
+// compacts the underlying goleveldb store.  Removing entries is a workaround for github issue #374.
+func (ldbs *Store) CompactWithBatchSize(batchSize int) error {
+	// workaround for github issue #374 - remove DictionaryTerm keys with count=0
+	batch := &leveldb.Batch{}
+	for {
+		t, err := ldbs.db.OpenTransaction()
+		if err != nil {
+			return err
+		}
+		iter := t.NewIterator(util.BytesPrefix([]byte("d")), ldbs.defaultReadOptions)
+
+		for iter.Next() {
+			if bytes.Equal(iter.Value(), []byte{0}) {
+				k := append([]byte{}, iter.Key()...)
+				batch.Delete(k)
+			}
+			if batch.Len() == batchSize {
+				break
+			}
+		}
+		iter.Release()
+		if iter.Error() != nil {
+			t.Discard()
+			return iter.Error()
+		}
+
+		if batch.Len() > 0 {
+			err := t.Write(batch, ldbs.defaultWriteOptions)
+			if err != nil {
+				t.Discard()
+				return err
+			}
+			err = t.Commit()
+			if err != nil {
+				return err
+			}
+		} else {
+			t.Discard()
+			break
+		}
+		batch.Reset()
+	}
+
+	return ldbs.db.CompactRange(util.Range{Start: nil, Limit: nil})
+}
+
+// Compact compacts the underlying goleveldb store.  The current implementation includes a workaround
+// for github issue #374 (see CompactWithBatchSize).
+func (ldbs *Store) Compact() error {
+	return ldbs.CompactWithBatchSize(defaultCompactBatchSize)
+}
+
+func init() {
+	err := registry.RegisterKVStore(Name, New)
+	if err != nil {
+		panic(err)
+	}
+}