initial commit

vendor/github.com/blevesearch/bleve/index/firestorm/version.go

@@ -0,0 +1,108 @@
+//  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 firestorm
+
+import (
+	"fmt"
+
+	"github.com/golang/protobuf/proto"
+
+	"github.com/blevesearch/bleve/index/store"
+)
+
+const Version uint64 = 1
+
+var IncompatibleVersion = fmt.Errorf("incompatible version, %d is supported", Version)
+
+var VersionKey = []byte{'v'}
+
+type VersionRow struct {
+	value VersionValue
+}
+
+func NewVersionRow(version uint64) *VersionRow {
+	rv := VersionRow{}
+	rv.value.Version = proto.Uint64(version)
+	return &rv
+}
+
+func NewVersionRowV(val []byte) (*VersionRow, error) {
+	rv := VersionRow{}
+	err := rv.value.Unmarshal(val)
+	if err != nil {
+		return nil, err
+	}
+	return &rv, nil
+}
+
+func (vr *VersionRow) KeySize() int {
+	return 1
+}
+
+func (vr *VersionRow) KeyTo(buf []byte) (int, error) {
+	buf[0] = VersionKey[0]
+	return 1, nil
+}
+
+func (vr *VersionRow) Key() []byte {
+	return VersionKey
+}
+
+func (vr *VersionRow) ValueSize() int {
+	return vr.value.Size()
+}
+
+func (vr *VersionRow) ValueTo(buf []byte) (int, error) {
+	return vr.value.MarshalTo(buf)
+}
+
+func (vr *VersionRow) Value() []byte {
+	buf := make([]byte, vr.ValueSize())
+	n, _ := vr.value.MarshalTo(buf)
+	return buf[:n]
+}
+
+func (vr *VersionRow) Version() uint64 {
+	return vr.value.GetVersion()
+}
+
+func (f *Firestorm) checkVersion(reader store.KVReader) (newIndex bool, err error) {
+	value, err := reader.Get(VersionKey)
+	if err != nil {
+		return
+	}
+
+	if value == nil {
+		newIndex = true
+		return
+	}
+
+	var vr *VersionRow
+	vr, err = NewVersionRowV(value)
+	if err != nil {
+		return
+	}
+
+	// assert correct version
+	if vr.Version() != Version {
+		err = IncompatibleVersion
+		return
+	}
+
+	return
+}
+
+func (f *Firestorm) storeVersion(writer store.KVWriter) error {
+	vr := NewVersionRow(Version)
+	wb := writer.NewBatch()
+	wb.Set(vr.Key(), vr.Value())
+	err := writer.ExecuteBatch(wb)
+	return err
+}