Adding upstream version 2.5.1.

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

index/upsidedown/store/boltdb/writer.go

@@ -0,0 +1,95 @@
+//  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 boltdb
+
+import (
+	"fmt"
+
+	store "github.com/blevesearch/upsidedown_store_api"
+)
+
+type Writer struct {
+	store *Store
+}
+
+func (w *Writer) NewBatch() store.KVBatch {
+	return store.NewEmulatedBatch(w.store.mo)
+}
+
+func (w *Writer) NewBatchEx(options store.KVBatchOptions) ([]byte, store.KVBatch, error) {
+	return make([]byte, options.TotalBytes), w.NewBatch(), nil
+}
+
+func (w *Writer) ExecuteBatch(batch store.KVBatch) (err error) {
+
+	emulatedBatch, ok := batch.(*store.EmulatedBatch)
+	if !ok {
+		return fmt.Errorf("wrong type of batch")
+	}
+
+	tx, err := w.store.db.Begin(true)
+	if err != nil {
+		return
+	}
+	// defer function to ensure that once started,
+	// we either Commit tx or Rollback
+	defer func() {
+		// if nothing went wrong, commit
+		if err == nil {
+			// careful to catch error here too
+			err = tx.Commit()
+		} else {
+			// caller should see error that caused abort,
+			// not success or failure of Rollback itself
+			_ = tx.Rollback()
+		}
+	}()
+
+	bucket := tx.Bucket([]byte(w.store.bucket))
+	bucket.FillPercent = w.store.fillPercent
+
+	for k, mergeOps := range emulatedBatch.Merger.Merges {
+		kb := []byte(k)
+		existingVal := bucket.Get(kb)
+		mergedVal, fullMergeOk := w.store.mo.FullMerge(kb, existingVal, mergeOps)
+		if !fullMergeOk {
+			err = fmt.Errorf("merge operator returned failure")
+			return
+		}
+		err = bucket.Put(kb, mergedVal)
+		if err != nil {
+			return
+		}
+	}
+
+	for _, op := range emulatedBatch.Ops {
+		if op.V != nil {
+			err = bucket.Put(op.K, op.V)
+			if err != nil {
+				return
+			}
+		} else {
+			err = bucket.Delete(op.K)
+			if err != nil {
+				return
+			}
+		}
+	}
+	return
+}
+
+func (w *Writer) Close() error {
+	return nil
+}