trie_delta.go

/*
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/ledger/statemgmt"
)

type levelDeltaMap map[string]*trieNode

type trieDelta struct {
	lowestLevel int
	deltaMap    map[int]levelDeltaMap
}

func newLevelDeltaMap() levelDeltaMap {
	return levelDeltaMap(make(map[string]*trieNode))
}

func newTrieDelta(stateDelta *statemgmt.StateDelta) *trieDelta {
	trieDelta := &trieDelta{0, make(map[int]levelDeltaMap)}
	chaincodes := stateDelta.GetUpdatedChaincodeIds(false)
	for _, chaincodeID := range chaincodes {
		updates := stateDelta.GetUpdates(chaincodeID)
		for key, updatedvalue := range updates {
			if updatedvalue.IsDelete() {
				trieDelta.delete(chaincodeID, key)
			} else {
				if stateDelta.RollBackwards {
					trieDelta.set(chaincodeID, key, updatedvalue.GetPreviousValue())
				} else {
					trieDelta.set(chaincodeID, key, updatedvalue.GetValue())
				}
			}
		}
	}
	return trieDelta
}

func (trieDelta *trieDelta) getLowestLevel() int {
	return trieDelta.lowestLevel
}

func (trieDelta *trieDelta) getChangesAtLevel(level int) []*trieNode {
	levelDelta := trieDelta.deltaMap[level]
	changedNodes := make([]*trieNode, len(levelDelta))
	for _, v := range levelDelta {
		changedNodes = append(changedNodes, v)
	}
	return changedNodes
}

func (trieDelta *trieDelta) getParentOf(trieNode *trieNode) *trieNode {
	parentLevel := trieNode.getParentLevel()
	parentTrieKey := trieNode.getParentTrieKey()
	levelDeltaMap := trieDelta.deltaMap[parentLevel]
	if levelDeltaMap == nil {
		return nil
	}
	return levelDeltaMap[parentTrieKey.getEncodedBytesAsStr()]
}

func (trieDelta *trieDelta) addTrieNode(trieNode *trieNode) {
	level := trieNode.getLevel()
	levelDeltaMap := trieDelta.deltaMap[level]
	if levelDeltaMap == nil {
		levelDeltaMap = newLevelDeltaMap()
		trieDelta.deltaMap[level] = levelDeltaMap
	}
	levelDeltaMap[trieNode.trieKey.getEncodedBytesAsStr()] = trieNode
	if level > trieDelta.lowestLevel {
		trieDelta.lowestLevel = level
	}
}

func (trieDelta *trieDelta) getTrieRootNode() *trieNode {
	levelZeroMap := trieDelta.deltaMap[0]
	if levelZeroMap == nil {
		return nil
	}
	return levelZeroMap[rootTrieKeyStr]
}

func (trieDelta *trieDelta) set(chaincodeId string, key string, value []byte) {
	trieNode := newTrieNode(newTrieKey(chaincodeId, key), value, true)
	trieDelta.addTrieNode(trieNode)
}

func (trieDelta *trieDelta) delete(chaincodeId string, key string) {
	trieDelta.set(chaincodeId, key, nil)
}