forked from hyperledger-archives/fabric
/
snapshot_iterator.go
73 lines (63 loc) · 2.64 KB
/
snapshot_iterator.go
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/*
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements. See the NOTICE file
distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file
to you 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 trie
import (
"github.com/openblockchain/obc-peer/openchain/db"
"github.com/openblockchain/obc-peer/openchain/ledger/statemgmt"
"github.com/openblockchain/obc-peer/openchain/ledger/util"
"github.com/tecbot/gorocksdb"
)
// StateSnapshotIterator implements the interface 'statemgmt.StateSnapshotIterator'
type StateSnapshotIterator struct {
dbItr *gorocksdb.Iterator
currentKey []byte
currentValue []byte
}
func newStateSnapshotIterator(snapshot *gorocksdb.Snapshot) (*StateSnapshotIterator, error) {
dbItr := db.GetDBHandle().GetStateCFSnapshotIterator(snapshot)
dbItr.SeekToFirst()
// skip the root key, because, the value test in Next method is misleading for root key as the value field
dbItr.Next()
return &StateSnapshotIterator{dbItr, nil, nil}, nil
}
// Next - see interface 'statemgmt.StateSnapshotIterator' for details
func (snapshotItr *StateSnapshotIterator) Next() bool {
var available bool
for ; snapshotItr.dbItr.Valid(); snapshotItr.dbItr.Next() {
// making a copy of key-value bytes because, underlying key bytes are reused by itr.
// no need to free slices as iterator frees memory when closed.
trieKeyBytes := statemgmt.Copy(snapshotItr.dbItr.Key().Data())
trieNodeBytes := statemgmt.Copy(snapshotItr.dbItr.Value().Data())
value := unmarshalTrieNodeValue(trieNodeBytes)
if util.NotNil(value) {
snapshotItr.currentKey = trieKeyEncoderImpl.decodeTrieKeyBytes(statemgmt.Copy(trieKeyBytes))
snapshotItr.currentValue = value
available = true
snapshotItr.dbItr.Next()
break
}
}
return available
}
// GetRawKeyValue - see interface 'statemgmt.StateSnapshotIterator' for details
func (snapshotItr *StateSnapshotIterator) GetRawKeyValue() ([]byte, []byte) {
return snapshotItr.currentKey, snapshotItr.currentValue
}
// Close - see interface 'statemgmt.StateSnapshotIterator' for details
func (snapshotItr *StateSnapshotIterator) Close() {
snapshotItr.dbItr.Close()
}