Adding upstream version 2.5.1.

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

index/upsidedown/store/boltdb/iterator.go

@@ -0,0 +1,85 @@
+//  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 (
+	"bytes"
+
+	bolt "go.etcd.io/bbolt"
+)
+
+type Iterator struct {
+	store  *Store
+	tx     *bolt.Tx
+	cursor *bolt.Cursor
+	prefix []byte
+	start  []byte
+	end    []byte
+	valid  bool
+	key    []byte
+	val    []byte
+}
+
+func (i *Iterator) updateValid() {
+	i.valid = (i.key != nil)
+	if i.valid {
+		if i.prefix != nil {
+			i.valid = bytes.HasPrefix(i.key, i.prefix)
+		} else if i.end != nil {
+			i.valid = bytes.Compare(i.key, i.end) < 0
+		}
+	}
+}
+
+func (i *Iterator) Seek(k []byte) {
+	if i.start != nil && bytes.Compare(k, i.start) < 0 {
+		k = i.start
+	}
+	if i.prefix != nil && !bytes.HasPrefix(k, i.prefix) {
+		if bytes.Compare(k, i.prefix) < 0 {
+			k = i.prefix
+		} else {
+			i.valid = false
+			return
+		}
+	}
+	i.key, i.val = i.cursor.Seek(k)
+	i.updateValid()
+}
+
+func (i *Iterator) Next() {
+	i.key, i.val = i.cursor.Next()
+	i.updateValid()
+}
+
+func (i *Iterator) Current() ([]byte, []byte, bool) {
+	return i.key, i.val, i.valid
+}
+
+func (i *Iterator) Key() []byte {
+	return i.key
+}
+
+func (i *Iterator) Value() []byte {
+	return i.val
+}
+
+func (i *Iterator) Valid() bool {
+	return i.valid
+}
+
+func (i *Iterator) Close() error {
+	return nil
+}