1 files changed, 245 insertions, 0 deletions
diff --git a/core/state/journal.go b/core/state/journal.go
new file mode 100644
index 0000000..6e85173
--- /dev/null
+++ b/core/state/journal.go
@@ -0,0 +1,245 @@
+// 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/ava-labs/go-ethereum/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
+	}
+	multiCoinEnable struct {
+		account *common.Address
+	}
+	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 multiCoinEnable) revert(s *StateDB) {
+	s.getStateObject(*ch.account).data.IsMultiCoin = false
+}
+
+func (ch multiCoinEnable) 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
+}