1 files changed, 117 insertions, 0 deletions
diff --git a/core/state/journal.go b/core/state/journal.go
new file mode 100644
index 000000000..540ade6fb
--- /dev/null
+++ b/core/state/journal.go
@@ -0,0 +1,117 @@
+// 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/ethereum/go-ethereum/common"
+)
+
+type journalEntry interface {
+	undo(*StateDB)
+}
+
+type journal []journalEntry
+
+type (
+	// Changes to the account trie.
+	createObjectChange struct {
+		account *common.Address
+	}
+	resetObjectChange struct {
+		prev *StateObject
+	}
+	deleteAccountChange 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 *big.Int
+	}
+	addLogChange struct {
+		txhash common.Hash
+	}
+)
+
+func (ch createObjectChange) undo(s *StateDB) {
+	s.GetStateObject(*ch.account).deleted = true
+	delete(s.stateObjects, *ch.account)
+	delete(s.stateObjectsDirty, *ch.account)
+}
+
+func (ch resetObjectChange) undo(s *StateDB) {
+	s.setStateObject(ch.prev)
+}
+
+func (ch deleteAccountChange) undo(s *StateDB) {
+	obj := s.GetStateObject(*ch.account)
+	if obj != nil {
+		obj.remove = ch.prev
+		obj.setBalance(ch.prevbalance)
+	}
+}
+
+func (ch balanceChange) undo(s *StateDB) {
+	s.GetStateObject(*ch.account).setBalance(ch.prev)
+}
+
+func (ch nonceChange) undo(s *StateDB) {
+	s.GetStateObject(*ch.account).setNonce(ch.prev)
+}
+
+func (ch codeChange) undo(s *StateDB) {
+	s.GetStateObject(*ch.account).setCode(common.BytesToHash(ch.prevhash), ch.prevcode)
+}
+
+func (ch storageChange) undo(s *StateDB) {
+	s.GetStateObject(*ch.account).setState(ch.key, ch.prevalue)
+}
+
+func (ch refundChange) undo(s *StateDB) {
+	s.refund = ch.prev
+}
+
+func (ch addLogChange) undo(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]
+	}
+}