// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package state
import (
"math/big"
"github.com/dexon-foundation/dexon/common"
)
// journalEntry is a modification entry in the state change journal that can be
// reverted on demand.
type journalEntry interface {
// revert undoes the changes introduced by this journal entry.
revert(*StateDB)
// dirtied returns the Ethereum address modified by this journal entry.
dirtied() *common.Address
}
// journal contains the list of state modifications applied since the last state
// commit. These are tracked to be able to be reverted in case of an execution
// exception or revertal request.
type journal struct {
entries []journalEntry // Current changes tracked by the journal
dirties map[common.Address]int // Dirty accounts and the number of changes
}
// newJournal create a new initialized journal.
func newJournal() *journal {
return &journal{
dirties: make(map[common.Address]int),
}
}
// append inserts a new modification entry to the end of the change journal.
func (j *journal) append(entry journalEntry) {
j.entries = append(j.entries, entry)
if addr := entry.dirtied(); addr != nil {
j.dirties[*addr]++
}
}
// revert undoes a batch of journalled modifications along with any reverted
// dirty handling too.
func (j *journal) revert(statedb *StateDB, snapshot int) {
for i := len(j.entries) - 1; i >= snapshot; i-- {
// Undo the changes made by the operation
j.entries[i].revert(statedb)
// Drop any dirty tracking induced by the change
if addr := j.entries[i].dirtied(); addr != nil {
if j.dirties[*addr]--; j.dirties[*addr] == 0 {
delete(j.dirties, *addr)
}
}
}
j.entries = j.entries[:snapshot]
}
// dirty explicitly sets an address to dirty, even if the change entries would
// otherwise suggest it as clean. This method is an ugly hack to handle the RIPEMD
// precompile consensus exception.
func (j *journal) dirty(addr common.Address) {
j.dirties[addr]++
}
// length returns the current number of entries in the journal.
func (j *journal) length() int {
return len(j.entries)
}
type (
// Changes to the account trie.
createObjectChange struct {
account *common.Address
}
resetObjectChange struct {
prev *stateObject
}
suicideChange struct {
account *common.Address
prev bool // whether account had already suicided
prevbalance *big.Int
}
// Changes to individual accounts.
balanceChange struct {
account *common.Address
prev *big.Int
}
nonceChange struct {
account *common.Address
prev uint64
}
storageChange struct {
account *common.Address
key, prevalue common.Hash
}
codeChange struct {
account *common.Address
prevcode, prevhash []byte
}
// Changes to other state values.
refundChange struct {
prev uint64
}
addLogChange struct {
txhash common.Hash
}
addPreimageChange struct {
hash common.Hash
}
touchChange struct {
account *common.Address
prev bool
prevDirty bool
}
)
func (ch createObjectChange) revert(s *StateDB) {
delete(s.stateObjects, *ch.account)
delete(s.stateObjectsDirty, *ch.account)
}
func (ch createObjectChange) dirtied() *common.Address {
return ch.account
}
func (ch resetObjectChange) revert(s *StateDB) {
s.setStateObject(ch.prev)
}
func (ch resetObjectChange) dirtied() *common.Address {
return nil
}
func (ch suicideChange) revert(s *StateDB) {
obj := s.getStateObject(*ch.account)
if obj != nil {
obj.suicided = ch.prev
obj.setBalance(ch.prevbalance)
}
}
func (ch suicideChange) dirtied() *common.Address {
return ch.account
}
var ripemd = common.HexToAddress("0000000000000000000000000000000000000003")
func (ch touchChange) revert(s *StateDB) {
}
func (ch touchChange) dirtied() *common.Address {
return ch.account
}
func (ch balanceChange) revert(s *StateDB) {
s.getStateObject(*ch.account).setBalance(ch.prev)
}
func (ch balanceChange) dirtied() *common.Address {
return ch.account
}
func (ch nonceChange) revert(s *StateDB) {
s.getStateObject(*ch.account).setNonce(ch.prev)
}
func (ch nonceChange) dirtied() *common.Address {
return ch.account
}
func (ch codeChange) revert(s *StateDB) {
s.getStateObject(*ch.account).setCode(common.BytesToHash(ch.prevhash), ch.prevcode)
}
func (ch codeChange) dirtied() *common.Address {
return ch.account
}
func (ch storageChange) revert(s *StateDB) {
s.getStateObject(*ch.account).setState(ch.key, ch.prevalue)
}
func (ch storageChange) dirtied() *common.Address {
return ch.account
}
func (ch refundChange) revert(s *StateDB) {
s.refund = ch.prev
}
func (ch refundChange) dirtied() *common.Address {
return nil
}
func (ch addLogChange) revert(s *StateDB) {
logs := s.logs[ch.txhash]
if len(logs) == 1 {
delete(s.logs, ch.txhash)
} else {
s.logs[ch.txhash] = logs[:len(logs)-1]
}
s.logSize--
}
func (ch addLogChange) dirtied() *common.Address {
return nil
}
func (ch addPreimageChange) revert(s *StateDB) {
delete(s.preimages, ch.hash)
}
func (ch addPreimageChange) dirtied() *common.Address {
return nil
}
