forked from ug93tad/fabric
/
range_scan_iterator.go
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/
range_scan_iterator.go
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/*
Copyright IBM Corp. 2016 All Rights Reserved.
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 trie
import (
"github.com/hyperledger/fabric/core/db"
"github.com/hyperledger/fabric/core/ledger/statemgmt"
"github.com/hyperledger/fabric/anh/tecbot/gorocksdb"
)
// RangeScanIterator implements the interface 'statemgmt.RangeScanIterator'
type RangeScanIterator struct {
dbItr *gorocksdb.Iterator
chaincodeID string
endKey string
currentKey string
currentValue []byte
done bool
}
func newRangeScanIterator(chaincodeID string, startKey string, endKey string) (*RangeScanIterator, error) {
dbItr := db.GetDBHandle().GetStateCFIterator()
encodedStartKey := newTrieKey(chaincodeID, startKey).getEncodedBytes()
dbItr.Seek(encodedStartKey)
return &RangeScanIterator{dbItr, chaincodeID, endKey, "", nil, false}, nil
}
// Next - see interface 'statemgmt.RangeScanIterator' for details
func (itr *RangeScanIterator) Next() bool {
if itr.done {
return false
}
for ; itr.dbItr.Valid(); itr.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(itr.dbItr.Key().Data())
trieNodeBytes := statemgmt.Copy(itr.dbItr.Value().Data())
value := unmarshalTrieNodeValue(trieNodeBytes)
if value == nil {
continue
}
// found an actual key
currentCompositeKey := trieKeyEncoderImpl.decodeTrieKeyBytes(statemgmt.Copy(trieKeyBytes))
currentChaincodeID, currentKey := statemgmt.DecodeCompositeKey(currentCompositeKey)
if currentChaincodeID == itr.chaincodeID && (itr.endKey == "" || currentKey <= itr.endKey) {
itr.currentKey = currentKey
itr.currentValue = value
itr.dbItr.Next()
return true
}
// retrieved all the keys in the given range
break
}
itr.done = true
return false
}
// GetKeyValue - see interface 'statemgmt.RangeScanIterator' for details
func (itr *RangeScanIterator) GetKeyValue() (string, []byte) {
return itr.currentKey, itr.currentValue
}
// Close - see interface 'statemgmt.RangeScanIterator' for details
func (itr *RangeScanIterator) Close() {
itr.dbItr.Close()
}