Adding upstream version 2.5.1.

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

index/upsidedown/store/gtreap/writer.go

@@ -0,0 +1,76 @@
+//  Copyright (c) 2015 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 gtreap provides an in-memory implementation of the
+// KVStore interfaces using the gtreap balanced-binary treap,
+// copy-on-write data structure.
+package gtreap
+
+import (
+	"fmt"
+	"math/rand"
+
+	"github.com/blevesearch/upsidedown_store_api"
+)
+
+type Writer struct {
+	s *Store
+}
+
+func (w *Writer) NewBatch() store.KVBatch {
+	return store.NewEmulatedBatch(w.s.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) error {
+
+	emulatedBatch, ok := batch.(*store.EmulatedBatch)
+	if !ok {
+		return fmt.Errorf("wrong type of batch")
+	}
+
+	w.s.m.Lock()
+	for k, mergeOps := range emulatedBatch.Merger.Merges {
+		kb := []byte(k)
+		var existingVal []byte
+		existingItem := w.s.t.Get(&Item{k: kb})
+		if existingItem != nil {
+			existingVal = w.s.t.Get(&Item{k: kb}).(*Item).v
+		}
+		mergedVal, fullMergeOk := w.s.mo.FullMerge(kb, existingVal, mergeOps)
+		if !fullMergeOk {
+			return fmt.Errorf("merge operator returned failure")
+		}
+		w.s.t = w.s.t.Upsert(&Item{k: kb, v: mergedVal}, rand.Int())
+	}
+
+	for _, op := range emulatedBatch.Ops {
+		if op.V != nil {
+			w.s.t = w.s.t.Upsert(&Item{k: op.K, v: op.V}, rand.Int())
+		} else {
+			w.s.t = w.s.t.Delete(&Item{k: op.K})
+		}
+	}
+	w.s.m.Unlock()
+
+	return nil
+}
+
+func (w *Writer) Close() error {
+	w.s = nil
+	return nil
+}