add lists to keep track of actually hacked files

1 files changed, 412 insertions, 270 deletions

diff --git a/core/state/statedb.go b/core/state/statedb.go
index 9c7535b..805c607 100644
--- a/core/state/statedb.go
+++ b/core/state/statedb.go
@@ -24,13 +24,15 @@ import (
 	"sort"
 	"time"
 
+	"github.com/ava-labs/coreth/core/rawdb"
+	"github.com/ava-labs/coreth/core/state/snapshot"
 	"github.com/ava-labs/coreth/core/types"
-	"github.com/ava-labs/go-ethereum/common"
-	"github.com/ava-labs/go-ethereum/crypto"
-	"github.com/ava-labs/go-ethereum/log"
-	"github.com/ava-labs/go-ethereum/metrics"
-	"github.com/ava-labs/go-ethereum/rlp"
-	"github.com/ava-labs/go-ethereum/trie"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/metrics"
+	"github.com/ethereum/go-ethereum/rlp"
+	"github.com/ethereum/go-ethereum/trie"
 )
 
 type revision struct {
@@ -42,9 +44,6 @@ var (
 	// emptyRoot is the known root hash of an empty trie.
 	emptyRoot = common.HexToHash("56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421")
 	zeroRoot  = common.HexToHash("0000000000000000000000000000000000000000000000000000000000000000")
-
-	// emptyCode is the known hash of the empty EVM bytecode.
-	emptyCode = crypto.Keccak256Hash(nil)
 )
 
 type proofList [][]byte
@@ -58,7 +57,7 @@ func (n *proofList) Delete(key []byte) error {
 	panic("not supported")
 }
 
-// StateDBs within the ethereum protocol are used to store anything
+// StateDB structs within the ethereum protocol are used to store anything
 // within the merkle trie. StateDBs take care of caching and storing
 // nested states. It's the general query interface to retrieve:
 // * Contracts
@@ -67,9 +66,16 @@ type StateDB struct {
 	db   Database
 	trie Trie
 
+	snaps         *snapshot.Tree
+	snap          snapshot.Snapshot
+	snapDestructs map[common.Hash]struct{}
+	snapAccounts  map[common.Hash][]byte
+	snapStorage   map[common.Hash]map[common.Hash][]byte
+
 	// This map holds 'live' objects, which will get modified while processing a state transition.
-	stateObjects      map[common.Address]*stateObject
-	stateObjectsDirty map[common.Address]struct{}
+	stateObjects        map[common.Address]*stateObject
+	stateObjectsPending map[common.Address]struct{} // State objects finalized but not yet written to the trie
+	stateObjectsDirty   map[common.Address]struct{} // State objects modified in the current execution
 
 	// DB error.
 	// State objects are used by the consensus core and VM which are
@@ -95,134 +101,157 @@ type StateDB struct {
 	nextRevisionId int
 
 	// Measurements gathered during execution for debugging purposes
-	AccountReads   time.Duration
-	AccountHashes  time.Duration
-	AccountUpdates time.Duration
-	AccountCommits time.Duration
-	StorageReads   time.Duration
-	StorageHashes  time.Duration
-	StorageUpdates time.Duration
-	StorageCommits time.Duration
-}
-
-// Create a new state from a given trie.
-func New(root common.Hash, db Database) (*StateDB, error) {
+	AccountReads         time.Duration
+	AccountHashes        time.Duration
+	AccountUpdates       time.Duration
+	AccountCommits       time.Duration
+	StorageReads         time.Duration
+	StorageHashes        time.Duration
+	StorageUpdates       time.Duration
+	StorageCommits       time.Duration
+	SnapshotAccountReads time.Duration
+	SnapshotStorageReads time.Duration
+	SnapshotCommits      time.Duration
+}
+
+// New creates a new state from a given trie.
+func New(root common.Hash, db Database, snaps *snapshot.Tree) (*StateDB, error) {
 	tr, err := db.OpenTrie(root)
 	if err != nil {
 		return nil, err
 	}
-	return &StateDB{
-		db:                db,
-		trie:              tr,
-		stateObjects:      make(map[common.Address]*stateObject),
-		stateObjectsDirty: make(map[common.Address]struct{}),
-		logs:              make(map[common.Hash][]*types.Log),
-		preimages:         make(map[common.Hash][]byte),
-		journal:           newJournal(),
-	}, nil
+	sdb := &StateDB{
+		db:                  db,
+		trie:                tr,
+		snaps:               snaps,
+		stateObjects:        make(map[common.Address]*stateObject),
+		stateObjectsPending: make(map[common.Address]struct{}),
+		stateObjectsDirty:   make(map[common.Address]struct{}),
+		logs:                make(map[common.Hash][]*types.Log),
+		preimages:           make(map[common.Hash][]byte),
+		journal:             newJournal(),
+	}
+	if sdb.snaps != nil {
+		if sdb.snap = sdb.snaps.Snapshot(root); sdb.snap != nil {
+			sdb.snapDestructs = make(map[common.Hash]struct{})
+			sdb.snapAccounts = make(map[common.Hash][]byte)
+			sdb.snapStorage = make(map[common.Hash]map[common.Hash][]byte)
+		}
+	}
+	return sdb, nil
 }
 
 // setError remembers the first non-nil error it is called with.
-func (self *StateDB) setError(err error) {
-	if self.dbErr == nil {
-		self.dbErr = err
+func (s *StateDB) setError(err error) {
+	if s.dbErr == nil {
+		s.dbErr = err
 	}
 }
 
-func (self *StateDB) Error() error {
-	return self.dbErr
+func (s *StateDB) Error() error {
+	return s.dbErr
 }
 
 // Reset clears out all ephemeral state objects from the state db, but keeps
 // the underlying state trie to avoid reloading data for the next operations.
-func (self *StateDB) Reset(root common.Hash) error {
-	tr, err := self.db.OpenTrie(root)
+func (s *StateDB) Reset(root common.Hash) error {
+	tr, err := s.db.OpenTrie(root)
 	if err != nil {
 		return err
 	}
-	self.trie = tr
-	self.stateObjects = make(map[common.Address]*stateObject)
-	self.stateObjectsDirty = make(map[common.Address]struct{})
-	self.thash = common.Hash{}
-	self.bhash = common.Hash{}
-	self.txIndex = 0
-	self.logs = make(map[common.Hash][]*types.Log)
-	self.logSize = 0
-	self.preimages = make(map[common.Hash][]byte)
-	self.clearJournalAndRefund()
+	s.trie = tr
+	s.stateObjects = make(map[common.Address]*stateObject)
+	s.stateObjectsPending = make(map[common.Address]struct{})
+	s.stateObjectsDirty = make(map[common.Address]struct{})
+	s.thash = common.Hash{}
+	s.bhash = common.Hash{}
+	s.txIndex = 0
+	s.logs = make(map[common.Hash][]*types.Log)
+	s.logSize = 0
+	s.preimages = make(map[common.Hash][]byte)
+	s.clearJournalAndRefund()
+
+	if s.snaps != nil {
+		s.snapAccounts, s.snapDestructs, s.snapStorage = nil, nil, nil
+		if s.snap = s.snaps.Snapshot(root); s.snap != nil {
+			s.snapDestructs = make(map[common.Hash]struct{})
+			s.snapAccounts = make(map[common.Hash][]byte)
+			s.snapStorage = make(map[common.Hash]map[common.Hash][]byte)
+		}
+	}
 	return nil
 }
 
-func (self *StateDB) AddLog(log *types.Log) {
-	self.journal.append(addLogChange{txhash: self.thash})
+func (s *StateDB) AddLog(log *types.Log) {
+	s.journal.append(addLogChange{txhash: s.thash})
 
-	log.TxHash = self.thash
-	log.BlockHash = self.bhash
-	log.TxIndex = uint(self.txIndex)
-	log.Index = self.logSize
-	self.logs[self.thash] = append(self.logs[self.thash], log)
-	self.logSize++
+	log.TxHash = s.thash
+	log.BlockHash = s.bhash
+	log.TxIndex = uint(s.txIndex)
+	log.Index = s.logSize
+	s.logs[s.thash] = append(s.logs[s.thash], log)
+	s.logSize++
 }
 
-func (self *StateDB) GetLogs(hash common.Hash) []*types.Log {
-	return self.logs[hash]
+func (s *StateDB) GetLogs(hash common.Hash) []*types.Log {
+	return s.logs[hash]
 }
 
-func (self *StateDB) Logs() []*types.Log {
+func (s *StateDB) Logs() []*types.Log {
 	var logs []*types.Log
-	for _, lgs := range self.logs {
+	for _, lgs := range s.logs {
 		logs = append(logs, lgs...)
 	}
 	return logs
 }
 
 // AddPreimage records a SHA3 preimage seen by the VM.
-func (self *StateDB) AddPreimage(hash common.Hash, preimage []byte) {
-	if _, ok := self.preimages[hash]; !ok {
-		self.journal.append(addPreimageChange{hash: hash})
+func (s *StateDB) AddPreimage(hash common.Hash, preimage []byte) {
+	if _, ok := s.preimages[hash]; !ok {
+		s.journal.append(addPreimageChange{hash: hash})
 		pi := make([]byte, len(preimage))
 		copy(pi, preimage)
-		self.preimages[hash] = pi
+		s.preimages[hash] = pi
 	}
 }
 
 // Preimages returns a list of SHA3 preimages that have been submitted.
-func (self *StateDB) Preimages() map[common.Hash][]byte {
-	return self.preimages
+func (s *StateDB) Preimages() map[common.Hash][]byte {
+	return s.preimages
 }
 
 // AddRefund adds gas to the refund counter
-func (self *StateDB) AddRefund(gas uint64) {
-	self.journal.append(refundChange{prev: self.refund})
-	self.refund += gas
+func (s *StateDB) AddRefund(gas uint64) {
+	s.journal.append(refundChange{prev: s.refund})
+	s.refund += gas
 }
 
 // SubRefund removes gas from the refund counter.
 // This method will panic if the refund counter goes below zero
-func (self *StateDB) SubRefund(gas uint64) {
-	self.journal.append(refundChange{prev: self.refund})
-	if gas > self.refund {
-		panic("Refund counter below zero")
+func (s *StateDB) SubRefund(gas uint64) {
+	s.journal.append(refundChange{prev: s.refund})
+	if gas > s.refund {
+		panic(fmt.Sprintf("Refund counter below zero (gas: %d > refund: %d)", gas, s.refund))
 	}
-	self.refund -= gas
+	s.refund -= gas
 }
 
 // Exist reports whether the given account address exists in the state.
 // Notably this also returns true for suicided accounts.
-func (self *StateDB) Exist(addr common.Address) bool {
-	return self.getStateObject(addr) != nil
+func (s *StateDB) Exist(addr common.Address) bool {
+	return s.getStateObject(addr) != nil
 }
 
 // Empty returns whether the state object is either non-existent
 // or empty according to the EIP161 specification (balance = nonce = code = 0)
-func (self *StateDB) Empty(addr common.Address) bool {
-	so := self.getStateObject(addr)
+func (s *StateDB) Empty(addr common.Address) bool {
+	so := s.getStateObject(addr)
 	return so == nil || so.empty()
 }
 
-// Retrieve the balance from the given address or 0 if object not found
-func (self *StateDB) GetBalance(addr common.Address) *big.Int {
-	stateObject := self.getStateObject(addr)
+// GetBalance retrieves the balance from the given address or 0 if object not found
+func (s *StateDB) GetBalance(addr common.Address) *big.Int {
+	stateObject := s.getStateObject(addr)
 	if stateObject != nil {
 		return stateObject.Balance()
 	}
@@ -262,8 +291,8 @@ func (self *StateDB) IsMultiCoin(addr common.Address) bool {
 	return false
 }
 
-func (self *StateDB) GetNonce(addr common.Address) uint64 {
-	stateObject := self.getStateObject(addr)
+func (s *StateDB) GetNonce(addr common.Address) uint64 {
+	stateObject := s.getStateObject(addr)
 	if stateObject != nil {
 		return stateObject.Nonce()
 	}
@@ -272,40 +301,33 @@ func (self *StateDB) GetNonce(addr common.Address) uint64 {
 }
 
 // TxIndex returns the current transaction index set by Prepare.
-func (self *StateDB) TxIndex() int {
-	return self.txIndex
+func (s *StateDB) TxIndex() int {
+	return s.txIndex
 }
 
 // BlockHash returns the current block hash set by Prepare.
-func (self *StateDB) BlockHash() common.Hash {
-	return self.bhash
+func (s *StateDB) BlockHash() common.Hash {
+	return s.bhash
 }
 
-func (self *StateDB) GetCode(addr common.Address) []byte {
-	stateObject := self.getStateObject(addr)
+func (s *StateDB) GetCode(addr common.Address) []byte {
+	stateObject := s.getStateObject(addr)
 	if stateObject != nil {
-		return stateObject.Code(self.db)
+		return stateObject.Code(s.db)
 	}
 	return nil
 }
 
-func (self *StateDB) GetCodeSize(addr common.Address) int {
-	stateObject := self.getStateObject(addr)
-	if stateObject == nil {
-		return 0
-	}
-	if stateObject.code != nil {
-		return len(stateObject.code)
-	}
-	size, err := self.db.ContractCodeSize(stateObject.addrHash, common.BytesToHash(stateObject.CodeHash()))
-	if err != nil {
-		self.setError(err)
+func (s *StateDB) GetCodeSize(addr common.Address) int {
+	stateObject := s.getStateObject(addr)
+	if stateObject != nil {
+		return stateObject.CodeSize(s.db)
 	}
-	return size
+	return 0
 }
 
-func (self *StateDB) GetCodeHash(addr common.Address) common.Hash {
-	stateObject := self.getStateObject(addr)
+func (s *StateDB) GetCodeHash(addr common.Address) common.Hash {
+	stateObject := s.getStateObject(addr)
 	if stateObject == nil {
 		return common.Hash{}
 	}
@@ -313,25 +335,25 @@ func (self *StateDB) GetCodeHash(addr common.Address) common.Hash {
 }
 
 // GetState retrieves a value from the given account's storage trie.
-func (self *StateDB) GetState(addr common.Address, hash common.Hash) common.Hash {
-	stateObject := self.getStateObject(addr)
+func (s *StateDB) GetState(addr common.Address, hash common.Hash) common.Hash {
+	stateObject := s.getStateObject(addr)
 	if stateObject != nil {
-		return stateObject.GetState(self.db, hash)
+		return stateObject.GetState(s.db, hash)
 	}
 	return common.Hash{}
 }
 
 // GetProof returns the MerkleProof for a given Account
-func (self *StateDB) GetProof(a common.Address) ([][]byte, error) {
+func (s *StateDB) GetProof(a common.Address) ([][]byte, error) {
 	var proof proofList
-	err := self.trie.Prove(crypto.Keccak256(a.Bytes()), 0, &proof)
+	err := s.trie.Prove(crypto.Keccak256(a.Bytes()), 0, &proof)
 	return [][]byte(proof), err
 }
 
-// GetProof returns the StorageProof for given key
-func (self *StateDB) GetStorageProof(a common.Address, key common.Hash) ([][]byte, error) {
+// GetStorageProof returns the StorageProof for given key
+func (s *StateDB) GetStorageProof(a common.Address, key common.Hash) ([][]byte, error) {
 	var proof proofList
-	trie := self.StorageTrie(a)
+	trie := s.StorageTrie(a)
 	if trie == nil {
 		return proof, errors.New("storage trie for requested address does not exist")
 	}
@@ -340,32 +362,33 @@ func (self *StateDB) GetStorageProof(a common.Address, key common.Hash) ([][]byt
 }
 
 // GetCommittedState retrieves a value from the given account's committed storage trie.
-func (self *StateDB) GetCommittedState(addr common.Address, hash common.Hash) common.Hash {
-	stateObject := self.getStateObject(addr)
+func (s *StateDB) GetCommittedState(addr common.Address, hash common.Hash) common.Hash {
+	stateObject := s.getStateObject(addr)
 	if stateObject != nil {
-		return stateObject.GetCommittedState(self.db, hash)
+		return stateObject.GetCommittedState(s.db, hash)
 	}
 	return common.Hash{}
 }
 
 // Database retrieves the low level database supporting the lower level trie ops.
-func (self *StateDB) Database() Database {
-	return self.db
+func (s *StateDB) Database() Database {
+	return s.db
 }
 
 // StorageTrie returns the storage trie of an account.
 // The return value is a copy and is nil for non-existent accounts.
-func (self *StateDB) StorageTrie(addr common.Address) Trie {
-	stateObject := self.getStateObject(addr)
+func (s *StateDB) StorageTrie(addr common.Address) Trie {
+	stateObject := s.getStateObject(addr)
 	if stateObject == nil {
 		return nil
 	}
-	cpy := stateObject.deepCopy(self)
-	return cpy.updateTrie(self.db)
+	cpy := stateObject.deepCopy(s)
+	cpy.updateTrie(s.db)
+	return cpy.getTrie(s.db)
 }
 
-func (self *StateDB) HasSuicided(addr common.Address) bool {
-	stateObject := self.getStateObject(addr)
+func (s *StateDB) HasSuicided(addr common.Address) bool {
+	stateObject := s.getStateObject(addr)
 	if stateObject != nil {
 		return stateObject.suicided
 	}
@@ -377,81 +400,81 @@ func (self *StateDB) HasSuicided(addr common.Address) bool {
  */
 
 // AddBalance adds amount to the account associated with addr.
-func (self *StateDB) AddBalance(addr common.Address, amount *big.Int) {
-	stateObject := self.GetOrNewStateObject(addr)
+func (s *StateDB) AddBalance(addr common.Address, amount *big.Int) {
+	stateObject := s.GetOrNewStateObject(addr)
 	if stateObject != nil {
 		stateObject.AddBalance(amount)
 	}
 }
 
 // SubBalance subtracts amount from the account associated with addr.
-func (self *StateDB) SubBalance(addr common.Address, amount *big.Int) {
-	stateObject := self.GetOrNewStateObject(addr)
+func (s *StateDB) SubBalance(addr common.Address, amount *big.Int) {
+	stateObject := s.GetOrNewStateObject(addr)
 	if stateObject != nil {
 		stateObject.SubBalance(amount)
 	}
 }
 
-func (self *StateDB) SetBalance(addr common.Address, amount *big.Int) {
-	stateObject := self.GetOrNewStateObject(addr)
+func (s *StateDB) SetBalance(addr common.Address, amount *big.Int) {
+	stateObject := s.GetOrNewStateObject(addr)
 	if stateObject != nil {
 		stateObject.SetBalance(amount)
 	}
 }
 
 // AddBalance adds amount to the account associated with addr.
-func (self *StateDB) AddBalanceMultiCoin(addr common.Address, coinID common.Hash, amount *big.Int) {
-	stateObject := self.GetOrNewStateObject(addr)
+func (s *StateDB) AddBalanceMultiCoin(addr common.Address, coinID common.Hash, amount *big.Int) {
+	stateObject := s.GetOrNewStateObject(addr)
 	if stateObject != nil {
-		stateObject.AddBalanceMultiCoin(coinID, amount, self.db)
+		stateObject.AddBalanceMultiCoin(coinID, amount, s.db)
 	}
 }
 
 // SubBalance subtracts amount from the account associated with addr.
-func (self *StateDB) SubBalanceMultiCoin(addr common.Address, coinID common.Hash, amount *big.Int) {
-	stateObject := self.GetOrNewStateObject(addr)
+func (s *StateDB) SubBalanceMultiCoin(addr common.Address, coinID common.Hash, amount *big.Int) {
+	stateObject := s.GetOrNewStateObject(addr)
 	if stateObject != nil {
-		stateObject.SubBalanceMultiCoin(coinID, amount, self.db)
+		stateObject.SubBalanceMultiCoin(coinID, amount, s.db)
 	}
 }
 
-func (self *StateDB) SetBalanceMultiCoin(addr common.Address, coinID common.Hash, amount *big.Int) {
-	stateObject := self.GetOrNewStateObject(addr)
+func (s *StateDB) SetBalanceMultiCoin(addr common.Address, coinID common.Hash, amount *big.Int) {
+	stateObject := s.GetOrNewStateObject(addr)
 	if stateObject != nil {
-		stateObject.SetBalanceMultiCoin(coinID, amount, self.db)
+		stateObject.SetBalanceMultiCoin(coinID, amount, s.db)
 	}
 }
 
-func (self *StateDB) SetNonce(addr common.Address, nonce uint64) {
-	stateObject := self.GetOrNewStateObject(addr)
+func (s *StateDB) SetNonce(addr common.Address, nonce uint64) {
+	stateObject := s.GetOrNewStateObject(addr)
 	if stateObject != nil {
 		stateObject.SetNonce(nonce)
 	}
 }
 
-func (self *StateDB) SetCode(addr common.Address, code []byte) {
-	stateObject := self.GetOrNewStateObject(addr)
+func (s *StateDB) SetCode(addr common.Address, code []byte) {
+	stateObject := s.GetOrNewStateObject(addr)
 	if stateObject != nil {
 		stateObject.SetCode(crypto.Keccak256Hash(code), code)
 	}
 }
 
-func (self *StateDB) SetState(addr common.Address, key, value common.Hash) (res error) {
+func (s *StateDB) SetState(addr common.Address, key, value common.Hash) (res error) {
 	res = nil
-	stateObject := self.GetOrNewStateObject(addr)
+	stateObject := s.GetOrNewStateObject(addr)
 	if stateObject != nil {
 		if stateObject.data.IsMultiCoin {
 			NormalizeStateKey(&key)
 		}
-		stateObject.SetState(self.db, key, value)
+		stateObject.SetState(s.db, key, value)
 	}
 	return
 }
 
 // SetStorage replaces the entire storage for the specified account with given
 // storage. This function should only be used for debugging.
-func (self *StateDB) SetStorage(addr common.Address, storage map[common.Hash]common.Hash) {
-	stateObject := self.GetOrNewStateObject(addr)
+func (s *StateDB) SetStorage(addr common.Address, storage map[common.Hash]common.Hash) {
+	stateObject := s.GetOrNewStateObject(addr)
 	if stateObject != nil {
 		stateObject.SetStorage(storage)
 	}
@@ -462,12 +485,12 @@ func (self *StateDB) SetStorage(addr common.Address, storage map[common.Hash]com
 //
 // The account's state object is still available until the state is committed,
 // getStateObject will return a non-nil account after Suicide.
-func (self *StateDB) Suicide(addr common.Address) bool {
-	stateObject := self.getStateObject(addr)
+func (s *StateDB) Suicide(addr common.Address) bool {
+	stateObject := s.getStateObject(addr)
 	if stateObject == nil {
 		return false
 	}
-	self.journal.append(suicideChange{
+	s.journal.append(suicideChange{
 		account:     &addr,
 		prev:        stateObject.suicided,
 		prevbalance: new(big.Int).Set(stateObject.Balance()),
@@ -483,90 +506,153 @@ func (self *StateDB) Suicide(addr common.Address) bool {
 //
 
 // updateStateObject writes the given object to the trie.
-func (s *StateDB) updateStateObject(stateObject *stateObject) {
+func (s *StateDB) updateStateObject(obj *stateObject) {
 	// Track the amount of time wasted on updating the account from the trie
 	if metrics.EnabledExpensive {
 		defer func(start time.Time) { s.AccountUpdates += time.Since(start) }(time.Now())
 	}
 	// Encode the account and update the account trie
-	addr := stateObject.Address()
+	addr := obj.Address()
 
-	data, err := rlp.EncodeToBytes(stateObject)
+	data, err := rlp.EncodeToBytes(obj)
 	if err != nil {
 		panic(fmt.Errorf("can't encode object at %x: %v", addr[:], err))
 	}
-	s.setError(s.trie.TryUpdate(addr[:], data))
+	if err = s.trie.TryUpdate(addr[:], data); err != nil {
+		s.setError(fmt.Errorf("updateStateObject (%x) error: %v", addr[:], err))
+	}
+
+	// If state snapshotting is active, cache the data til commit. Note, this
+	// update mechanism is not symmetric to the deletion, because whereas it is
+	// enough to track account updates at commit time, deletions need tracking
+	// at transaction boundary level to ensure we capture state clearing.
+	if s.snap != nil {
+		s.snapAccounts[obj.addrHash] = snapshot.SlimAccountRLP(obj.data.Nonce, obj.data.Balance, obj.data.Root, obj.data.CodeHash)
+	}
 }
 
 // deleteStateObject removes the given object from the state trie.
-func (s *StateDB) deleteStateObject(stateObject *stateObject) {
+func (s *StateDB) deleteStateObject(obj *stateObject) {
 	// Track the amount of time wasted on deleting the account from the trie
 	if metrics.EnabledExpensive {
 		defer func(start time.Time) { s.AccountUpdates += time.Since(start) }(time.Now())
 	}
 	// Delete the account from the trie
-	stateObject.deleted = true
+	addr := obj.Address()
+	if err := s.trie.TryDelete(addr[:]); err != nil {
+		s.setError(fmt.Errorf("deleteStateObject (%x) error: %v", addr[:], err))
+	}
+}
 
-	addr := stateObject.Address()
-	s.setError(s.trie.TryDelete(addr[:]))
+// getStateObject retrieves a state object given by the address, returning nil if
+// the object is not found or was deleted in this execution context. If you need
+// to differentiate between non-existent/just-deleted, use getDeletedStateObject.
+func (s *StateDB) getStateObject(addr common.Address) *stateObject {
+	if obj := s.getDeletedStateObject(addr); obj != nil && !obj.deleted {
+		return obj
+	}
+	return nil
 }
 
-// Retrieve a state object given by the address. Returns nil if not found.
-func (s *StateDB) getStateObject(addr common.Address) (stateObject *stateObject) {
-	// Prefer live objects
+// getDeletedStateObject is similar to getStateObject, but instead of returning
+// nil for a deleted state object, it returns the actual object with the deleted
+// flag set. This is needed by the state journal to revert to the correct s-
+// destructed object instead of wiping all knowledge about the state object.
+func (s *StateDB) getDeletedStateObject(addr common.Address) *stateObject {
+	// Prefer live objects if any is available
 	if obj := s.stateObjects[addr]; obj != nil {
-		if obj.deleted {
-			return nil
-		}
 		return obj
 	}
-	// Track the amount of time wasted on loading the object from the database
-	if metrics.EnabledExpensive {
-		defer func(start time.Time) { s.AccountReads += time.Since(start) }(time.Now())
-	}
-	// Load the object from the database
-	enc, err := s.trie.TryGet(addr[:])
-	if len(enc) == 0 {
-		s.setError(err)
-		return nil
+	// If no live objects are available, attempt to use snapshots
+	var (
+		data *Account
+		err  error
+	)
+	if s.snap != nil {
+		if metrics.EnabledExpensive {
+			defer func(start time.Time) { s.SnapshotAccountReads += time.Since(start) }(time.Now())
+		}
+		var acc *snapshot.Account
+		if acc, err = s.snap.Account(crypto.Keccak256Hash(addr.Bytes())); err == nil {
+			if acc == nil {
+				return nil
+			}
+			data = &Account{
+				Nonce:    acc.Nonce,
+				Balance:  acc.Balance,
+				CodeHash: acc.CodeHash,
+				Root:     common.BytesToHash(acc.Root),
+			}
+			if len(data.CodeHash) == 0 {
+				data.CodeHash = emptyCodeHash
+			}
+			if data.Root == (common.Hash{}) {
+				data.Root = emptyRoot
+			}
+		}
 	}
-	var data Account
-	if err := rlp.DecodeBytes(enc, &data); err != nil {
-		log.Error("Failed to decode state object", "addr", addr, "err", err)
-		return nil
+	// If snapshot unavailable or reading from it failed, load from the database
+	if s.snap == nil || err != nil {
+		if metrics.EnabledExpensive {
+			defer func(start time.Time) { s.AccountReads += time.Since(start) }(time.Now())
+		}
+		enc, err := s.trie.TryGet(addr.Bytes())
+		if err != nil {
+			s.setError(fmt.Errorf("getDeleteStateObject (%x) error: %v", addr.Bytes(), err))
+			return nil
+		}
+		if len(enc) == 0 {
+			return nil
+		}
+		data = new(Account)
+		if err := rlp.DecodeBytes(enc, data); err != nil {
+			log.Error("Failed to decode state object", "addr", addr, "err", err)
+			return nil
+		}
 	}
 	// Insert into the live set
-	obj := newObject(s, addr, data)
+	obj := newObject(s, addr, *data)
 	s.setStateObject(obj)
 	return obj
 }
 
-func (self *StateDB) setStateObject(object *stateObject) {
-	self.stateObjects[object.Address()] = object
+func (s *StateDB) setStateObject(object *stateObject) {
+	s.stateObjects[object.Address()] = object
 }
 
-// Retrieve a state object or create a new state object if nil.
-func (self *StateDB) GetOrNewStateObject(addr common.Address) *stateObject {
-	stateObject := self.getStateObject(addr)
-	if stateObject == nil || stateObject.deleted {
-		stateObject, _ = self.createObject(addr)
+// GetOrNewStateObject retrieves a state object or create a new state object if nil.
+func (s *StateDB) GetOrNewStateObject(addr common.Address) *stateObject {
+	stateObject := s.getStateObject(addr)
+	if stateObject == nil {
+		stateObject, _ = s.createObject(addr)
 	}
 	return stateObject
 }
 
 // createObject creates a new state object. If there is an existing account with
 // the given address, it is overwritten and returned as the second return value.
-func (self *StateDB) createObject(addr common.Address) (newobj, prev *stateObject) {
-	prev = self.getStateObject(addr)
-	newobj = newObject(self, addr, Account{})
+func (s *StateDB) createObject(addr common.Address) (newobj, prev *stateObject) {
+	prev = s.getDeletedStateObject(addr) // Note, prev might have been deleted, we need that!
+
+	var prevdestruct bool
+	if s.snap != nil && prev != nil {
+		_, prevdestruct = s.snapDestructs[prev.addrHash]
+		if !prevdestruct {
+			s.snapDestructs[prev.addrHash] = struct{}{}
+		}
+	}
+	newobj = newObject(s, addr, Account{})
 	newobj.setNonce(0) // sets the object to dirty
 	if prev == nil {
-		self.journal.append(createObjectChange{account: &addr})
+		s.journal.append(createObjectChange{account: &addr})
 	} else {
-		self.journal.append(resetObjectChange{prev: prev})
+		s.journal.append(resetObjectChange{prev: prev, prevdestruct: prevdestruct})
+	}
+	s.setStateObject(newobj)
+	if prev != nil && !prev.deleted {
+		return newobj, prev
 	}
-	self.setStateObject(newobj)
-	return newobj, prev
+	return newobj, nil
 }
 
 // CreateAccount explicitly creates a state object. If a state object with the address
@@ -579,8 +665,8 @@ func (self *StateDB) createObject(addr common.Address) (newobj, prev *stateObjec
 //   2. tx_create(sha(account ++ nonce)) (note that this gets the address of 1)
 //
 // Carrying over the balance ensures that Ether doesn't disappear.
-func (self *StateDB) CreateAccount(addr common.Address) {
-	newObj, prev := self.createObject(addr)
+func (s *StateDB) CreateAccount(addr common.Address) {
+	newObj, prev := s.createObject(addr)
 	if prev != nil {
 		newObj.setBalance(prev.data.Balance)
 	}
@@ -617,40 +703,52 @@ func (db *StateDB) ForEachStorage(addr common.Address, cb func(key, value common
 
 // Copy creates a deep, independent copy of the state.
 // Snapshots of the copied state cannot be applied to the copy.
-func (self *StateDB) Copy() *StateDB {
+func (s *StateDB) Copy() *StateDB {
 	// Copy all the basic fields, initialize the memory ones
 	state := &StateDB{
-		db:                self.db,
-		trie:              self.db.CopyTrie(self.trie),
-		stateObjects:      make(map[common.Address]*stateObject, len(self.journal.dirties)),
-		stateObjectsDirty: make(map[common.Address]struct{}, len(self.journal.dirties)),
-		refund:            self.refund,
-		logs:              make(map[common.Hash][]*types.Log, len(self.logs)),
-		logSize:           self.logSize,
-		preimages:         make(map[common.Hash][]byte, len(self.preimages)),
-		journal:           newJournal(),
+		db:                  s.db,
+		trie:                s.db.CopyTrie(s.trie),
+		stateObjects:        make(map[common.Address]*stateObject, len(s.journal.dirties)),
+		stateObjectsPending: make(map[common.Address]struct{}, len(s.stateObjectsPending)),
+		stateObjectsDirty:   make(map[common.Address]struct{}, len(s.journal.dirties)),
+		refund:              s.refund,
+		logs:                make(map[common.Hash][]*types.Log, len(s.logs)),
+		logSize:             s.logSize,
+		preimages:           make(map[common.Hash][]byte, len(s.preimages)),
+		journal:             newJournal(),
 	}
 	// Copy the dirty states, logs, and preimages
-	for addr := range self.journal.dirties {
+	for addr := range s.journal.dirties {
 		// As documented [here](https://github.com/ethereum/go-ethereum/pull/16485#issuecomment-380438527),
 		// and in the Finalise-method, there is a case where an object is in the journal but not
 		// in the stateObjects: OOG after touch on ripeMD prior to Byzantium. Thus, we need to check for
 		// nil
-		if object, exist := self.stateObjects[addr]; exist {
+		if object, exist := s.stateObjects[addr]; exist {
+			// Even though the original object is dirty, we are not copying the journal,
+			// so we need to make sure that anyside effect the journal would have caused
+			// during a commit (or similar op) is already applied to the copy.
 			state.stateObjects[addr] = object.deepCopy(state)
-			state.stateObjectsDirty[addr] = struct{}{}
+
+			state.stateObjectsDirty[addr] = struct{}{}   // Mark the copy dirty to force internal (code/state) commits
+			state.stateObjectsPending[addr] = struct{}{} // Mark the copy pending to force external (account) commits
 		}
 	}
 	// Above, we don't copy the actual journal. This means that if the copy is copied, the
 	// loop above will be a no-op, since the copy's journal is empty.
 	// Thus, here we iterate over stateObjects, to enable copies of copies
-	for addr := range self.stateObjectsDirty {
+	for addr := range s.stateObjectsPending {
+		if _, exist := state.stateObjects[addr]; !exist {
+			state.stateObjects[addr] = s.stateObjects[addr].deepCopy(state)
+		}
+		state.stateObjectsPending[addr] = struct{}{}
+	}
+	for addr := range s.stateObjectsDirty {
 		if _, exist := state.stateObjects[addr]; !exist {
-			state.stateObjects[addr] = self.stateObjects[addr].deepCopy(state)
-			state.stateObjectsDirty[addr] = struct{}{}
+			state.stateObjects[addr] = s.stateObjects[addr].deepCopy(state)
 		}
+		state.stateObjectsDirty[addr] = struct{}{}
 	}
-	for hash, logs := range self.logs {
+	for hash, logs := range s.logs {
 		cpy := make([]*types.Log, len(logs))
 		for i, l := range logs {
 			cpy[i] = new(types.Log)
@@ -658,46 +756,47 @@ func (self *StateDB) Copy() *StateDB {
 		}
 		state.logs[hash] = cpy
 	}
-	for hash, preimage := range self.preimages {
+	for hash, preimage := range s.preimages {
 		state.preimages[hash] = preimage
 	}
 	return state
 }
 
 // Snapshot returns an identifier for the current revision of the state.
-func (self *StateDB) Snapshot() int {
-	id := self.nextRevisionId
-	self.nextRevisionId++
-	self.validRevisions = append(self.validRevisions, revision{id, self.journal.length()})
+func (s *StateDB) Snapshot() int {
+	id := s.nextRevisionId
+	s.nextRevisionId++
+	s.validRevisions = append(s.validRevisions, revision{id, s.journal.length()})
 	return id
 }
 
 // RevertToSnapshot reverts all state changes made since the given revision.
-func (self *StateDB) RevertToSnapshot(revid int) {
+func (s *StateDB) RevertToSnapshot(revid int) {
 	// Find the snapshot in the stack of valid snapshots.
-	idx := sort.Search(len(self.validRevisions), func(i int) bool {
-		return self.validRevisions[i].id >= revid
+	idx := sort.Search(len(s.validRevisions), func(i int) bool {
+		return s.validRevisions[i].id >= revid
 	})
-	if idx == len(self.validRevisions) || self.validRevisions[idx].id != revid {
+	if idx == len(s.validRevisions) || s.validRevisions[idx].id != revid {
 		panic(fmt.Errorf("revision id %v cannot be reverted", revid))
 	}
-	snapshot := self.validRevisions[idx].journalIndex
+	snapshot := s.validRevisions[idx].journalIndex
 
 	// Replay the journal to undo changes and remove invalidated snapshots
-	self.journal.revert(self, snapshot)
-	self.validRevisions = self.validRevisions[:idx]
+	s.journal.revert(s, snapshot)
+	s.validRevisions = s.validRevisions[:idx]
 }
 
 // GetRefund returns the current value of the refund counter.
-func (self *StateDB) GetRefund() uint64 {
-	return self.refund
+func (s *StateDB) GetRefund() uint64 {
+	return s.refund
 }
 
-// Finalise finalises the state by removing the self destructed objects
-// and clears the journal as well as the refunds.
+// Finalise finalises the state by removing the s destructed objects and clears
+// the journal as well as the refunds. Finalise, however, will not push any updates
+// into the tries just yet. Only IntermediateRoot or Commit will do that.
 func (s *StateDB) Finalise(deleteEmptyObjects bool) {
 	for addr := range s.journal.dirties {
-		stateObject, exist := s.stateObjects[addr]
+		obj, exist := s.stateObjects[addr]
 		if !exist {
 			// ripeMD is 'touched' at block 1714175, in tx 0x1237f737031e40bcde4a8b7e717b2d15e3ecadfe49bb1bbc71ee9deb09c6fcf2
 			// That tx goes out of gas, and although the notion of 'touched' does not exist there, the
@@ -707,13 +806,22 @@ func (s *StateDB) Finalise(deleteEmptyObjects bool) {
 			// Thus, we can safely ignore it here
 			continue
 		}
-
-		if stateObject.suicided || (deleteEmptyObjects && stateObject.empty()) {
-			s.deleteStateObject(stateObject)
+		if obj.suicided || (deleteEmptyObjects && obj.empty()) {
+			obj.deleted = true
+
+			// If state snapshotting is active, also mark the destruction there.
+			// Note, we can't do this only at the end of a block because multiple
+			// transactions within the same block might self destruct and then
+			// ressurrect an account; but the snapshotter needs both events.
+			if s.snap != nil {
+				s.snapDestructs[obj.addrHash] = struct{}{} // We need to maintain account deletions explicitly (will remain set indefinitely)
+				delete(s.snapAccounts, obj.addrHash)       // Clear out any previously updated account data (may be recreated via a ressurrect)
+				delete(s.snapStorage, obj.addrHash)        // Clear out any previously updated storage data (may be recreated via a ressurrect)
+			}
 		} else {
-			stateObject.updateRoot(s.db)
-			s.updateStateObject(stateObject)
+			obj.finalise()
 		}
+		s.stateObjectsPending[addr] = struct{}{}
 		s.stateObjectsDirty[addr] = struct{}{}
 	}
 	// Invalidate journal because reverting across transactions is not allowed.
@@ -724,8 +832,21 @@ func (s *StateDB) Finalise(deleteEmptyObjects bool) {
 // It is called in between transactions to get the root hash that
 // goes into transaction receipts.
 func (s *StateDB) IntermediateRoot(deleteEmptyObjects bool) common.Hash {
+	// Finalise all the dirty storage states and write them into the tries
 	s.Finalise(deleteEmptyObjects)
 
+	for addr := range s.stateObjectsPending {
+		obj := s.stateObjects[addr]
+		if obj.deleted {
+			s.deleteStateObject(obj)
+		} else {
+			obj.updateRoot(s.db)
+			s.updateStateObject(obj)
+		}
+	}
+	if len(s.stateObjectsPending) > 0 {
+		s.stateObjectsPending = make(map[common.Address]struct{})
+	}
 	// Track the amount of time wasted on hashing the account trie
 	if metrics.EnabledExpensive {
 		defer func(start time.Time) { s.AccountHashes += time.Since(start) }(time.Now())
@@ -735,65 +856,86 @@ func (s *StateDB) IntermediateRoot(deleteEmptyObjects bool) common.Hash {
 
 // Prepare sets the current transaction hash and index and block hash which is
 // used when the EVM emits new state logs.
-func (self *StateDB) Prepare(thash, bhash common.Hash, ti int) {
-	self.thash = thash
-	self.bhash = bhash
-	self.txIndex = ti
+func (s *StateDB) Prepare(thash, bhash common.Hash, ti int) {
+	s.thash = thash
+	s.bhash = bhash
+	s.txIndex = ti
 }
 
 func (s *StateDB) clearJournalAndRefund() {
-	s.journal = newJournal()
-	s.validRevisions = s.validRevisions[:0]
-	s.refund = 0
+	if len(s.journal.entries) > 0 {
+		s.journal = newJournal()
+		s.refund = 0
+	}
+	s.validRevisions = s.validRevisions[:0] // Snapshots can be created without journal entires
 }
 
 // Commit writes the state to the underlying in-memory trie database.
-func (s *StateDB) Commit(deleteEmptyObjects bool) (root common.Hash, err error) {
-	defer s.clearJournalAndRefund()
-
-	for addr := range s.journal.dirties {
-		s.stateObjectsDirty[addr] = struct{}{}
+func (s *StateDB) Commit(deleteEmptyObjects bool) (common.Hash, error) {
+	if s.dbErr != nil {
+		return common.Hash{}, fmt.Errorf("commit aborted due to earlier error: %v", s.dbErr)
 	}
+	// Finalize any pending changes and merge everything into the tries
+	s.IntermediateRoot(deleteEmptyObjects)
+
 	// Commit objects to the trie, measuring the elapsed time
-	for addr, stateObject := range s.stateObjects {
-		_, isDirty := s.stateObjectsDirty[addr]
-		switch {
-		case stateObject.suicided || (isDirty && deleteEmptyObjects && stateObject.empty()):
-			// If the object has been removed, don't bother syncing it
-			// and just mark it for deletion in the trie.
-			s.deleteStateObject(stateObject)
-		case isDirty:
+	codeWriter := s.db.TrieDB().DiskDB().NewBatch()
+	for addr := range s.stateObjectsDirty {
+		if obj := s.stateObjects[addr]; !obj.deleted {
 			// Write any contract code associated with the state object
-			if stateObject.code != nil && stateObject.dirtyCode {
-				s.db.TrieDB().InsertBlob(common.BytesToHash(stateObject.CodeHash()), stateObject.code)
-				stateObject.dirtyCode = false
+			if obj.code != nil && obj.dirtyCode {
+				rawdb.WriteCode(codeWriter, common.BytesToHash(obj.CodeHash()), obj.code)
+				obj.dirtyCode = false
 			}
-			// Write any storage changes in the state object to its storage trie.
-			if err := stateObject.CommitTrie(s.db); err != nil {
+			// Write any storage changes in the state object to its storage trie
+			if err := obj.CommitTrie(s.db); err != nil {
 				return common.Hash{}, err
 			}
-			// Update the object in the main account trie.
-			s.updateStateObject(stateObject)
 		}
-		delete(s.stateObjectsDirty, addr)
+	}
+	if len(s.stateObjectsDirty) > 0 {
+		s.stateObjectsDirty = make(map[common.Address]struct{})
+	}
+	if codeWriter.ValueSize() > 0 {
+		if err := codeWriter.Write(); err != nil {
+			log.Crit("Failed to commit dirty codes", "error", err)
+		}
 	}
 	// Write the account trie changes, measuing the amount of wasted time
+	var start time.Time
 	if metrics.EnabledExpensive {
-		defer func(start time.Time) { s.AccountCommits += time.Since(start) }(time.Now())
+		start = time.Now()
 	}
-	root, err = s.trie.Commit(func(leaf []byte, parent common.Hash) error {
-		var account Account
+	// The onleaf func is called _serially_, so we can reuse the same account
+	// for unmarshalling every time.
+	var account Account
+	root, err := s.trie.Commit(func(path []byte, leaf []byte, parent common.Hash) error {
 		if err := rlp.DecodeBytes(leaf, &account); err != nil {
 			return nil
 		}
 		if account.Root != emptyRoot {
 			s.db.TrieDB().Reference(account.Root, parent)
 		}
-		code := common.BytesToHash(account.CodeHash)
-		if code != emptyCode {
-			s.db.TrieDB().Reference(code, parent)
-		}
 		return nil
 	})
+	if metrics.EnabledExpensive {
+		s.AccountCommits += time.Since(start)
+	}
+	// If snapshotting is enabled, update the snapshot tree with this new version
+	if s.snap != nil {
+		if metrics.EnabledExpensive {
+			defer func(start time.Time) { s.SnapshotCommits += time.Since(start) }(time.Now())
+		}
+		// Only update if there's a state transition (skip empty Clique blocks)
+		if parent := s.snap.Root(); parent != root {
+			if err := s.snaps.Update(root, parent, s.snapDestructs, s.snapAccounts, s.snapStorage); err != nil {
+				log.Warn("Failed to update snapshot tree", "from", parent, "to", root, "err", err)
+			}
+			if err := s.snaps.Cap(root, 127); err != nil { // Persistent layer is 128th, the last available trie
+				log.Warn("Failed to cap snapshot tree", "root", root, "layers", 127, "err", err)
+			}
+		}
+		s.snap, s.snapDestructs, s.snapAccounts, s.snapStorage = nil, nil, nil, nil
+	}
 	return root, err
 }