core/state: implement reverts by journaling all changes

This commit replaces the deep-copy based state revert mechanism with a
linear complexity journal. This commit also hides several internal
StateDB methods to limit the number of ways in which calling code can
use the journal incorrectly.

As usual consultation and bug fixes to the initial implementation were
provided by @karalabe, @obscuren and @Arachnid. Thank you!

1 files changed, 20 insertions, 14 deletions

diff --git a/tests/util.go b/tests/util.go
index ffbcb9d56..8a9d09213 100644
--- a/tests/util.go
+++ b/tests/util.go
@@ -103,19 +103,25 @@ func (self Log) Topics() [][]byte {
 	return t
 }
 
-func StateObjectFromAccount(db ethdb.Database, addr string, account Account, onDirty func(common.Address)) *state.StateObject {
+func makePreState(db ethdb.Database, accounts map[string]Account) *state.StateDB {
+	statedb, _ := state.New(common.Hash{}, db)
+	for addr, account := range accounts {
+		insertAccount(statedb, addr, account)
+	}
+	return statedb
+}
+
+func insertAccount(state *state.StateDB, saddr string, account Account) {
 	if common.IsHex(account.Code) {
 		account.Code = account.Code[2:]
 	}
-	code := common.Hex2Bytes(account.Code)
-	codeHash := crypto.Keccak256Hash(code)
-	obj := state.NewObject(common.HexToAddress(addr), state.Account{
-		Balance:  common.Big(account.Balance),
-		CodeHash: codeHash[:],
-		Nonce:    common.Big(account.Nonce).Uint64(),
-	}, onDirty)
-	obj.SetCode(codeHash, code)
-	return obj
+	addr := common.HexToAddress(saddr)
+	state.SetCode(addr, common.Hex2Bytes(account.Code))
+	state.SetNonce(addr, common.Big(account.Nonce).Uint64())
+	state.SetBalance(addr, common.Big(account.Balance))
+	for a, v := range account.Storage {
+		state.SetState(addr, common.HexToHash(a), common.HexToHash(v))
+	}
 }
 
 type VmEnv struct {
@@ -229,11 +235,11 @@ func (self *Env) CanTransfer(from common.Address, balance *big.Int) bool {
 
 	return self.state.GetBalance(from).Cmp(balance) >= 0
 }
-func (self *Env) MakeSnapshot() vm.Database {
-	return self.state.Copy()
+func (self *Env) SnapshotDatabase() int {
+	return self.state.Snapshot()
 }
-func (self *Env) SetSnapshot(copy vm.Database) {
-	self.state.Set(copy.(*state.StateDB))
+func (self *Env) RevertToSnapshot(snapshot int) {
+	self.state.RevertToSnapshot(snapshot)
 }
 
 func (self *Env) Transfer(from, to vm.Account, amount *big.Int) {