core, params: polish net gas metering PR a bit

Author: karalabe

core/state/state_object.go

@@ -77,9 +77,9 @@ type stateObject struct {
 	trie Trie // storage trie, which becomes non-nil on first access
 	code Code // contract bytecode, which gets set when code is loaded
 
-	cachedStorage Storage // Storage entry cache to avoid duplicate reads
+	originStorage Storage // Storage cache of original entries to dedup rewrites
 	dirtyStorage  Storage // Storage entries that need to be flushed to disk
-	originalValue Storage // Map of original storage values, at the beginning of current call context
+
 	// Cache flags.
 	// When an object is marked suicided it will be delete from the trie
 	// during the "update" phase of the state transition.
@@ -115,9 +115,8 @@ func newObject(db *StateDB, address common.Address, data Account) *stateObject {
 		address:       address,
 		addrHash:      crypto.Keccak256Hash(address[:]),
 		data:          data,
-		cachedStorage: make(Storage),
+		originStorage: make(Storage),
 		dirtyStorage:  make(Storage),
-		originalValue: make(Storage),
 	}
 }
 
@@ -160,13 +159,25 @@ func (c *stateObject) getTrie(db Database) Trie {
 	return c.trie
 }
 
-// GetState returns a value in account storage.
+// GetState retrieves a value from the account storage trie.
 func (self *stateObject) GetState(db Database, key common.Hash) common.Hash {
-	value, exists := self.cachedStorage[key]
-	if exists {
+	// If we have a dirty value for this state entry, return it
+	value, dirty := self.dirtyStorage[key]
+	if dirty {
+		return value
+	}
+	// Otherwise return the entry's original value
+	return self.GetCommittedState(db, key)
+}
+
+// GetCommittedState retrieves a value from the committed account storage trie.
+func (self *stateObject) GetCommittedState(db Database, key common.Hash) common.Hash {
+	// If we have the original value cached, return that
+	value, cached := self.originStorage[key]
+	if cached {
 		return value
 	}
-	// Load from DB in case it is missing.
+	// Otherwise load the value from the database
 	enc, err := self.getTrie(db).TryGet(key[:])
 	if err != nil {
 		self.setError(err)
@@ -179,37 +190,27 @@ func (self *stateObject) GetState(db Database, key common.Hash) common.Hash {
 		}
 		value.SetBytes(content)
 	}
-	self.cachedStorage[key] = value
+	self.originStorage[key] = value
 	return value
 }
 
-// GetOriginalStateValue returns the state value that is currently in the Trie, that is, ignoring any
-// changes that have been made but not yet written to trie.
-func (self *stateObject) GetOriginalStateValue(db Database, key common.Hash) common.Hash{
-	if original, exist:= self.originalValue[key]; exist {
-		// original value has been set, return it
-		return original
-	}
-	return self.GetState(db, key)
-}
-
 // SetState updates a value in account storage.
 func (self *stateObject) SetState(db Database, key, value common.Hash) {
+	// If the new value is the same as old, don't set
 	prev := self.GetState(db, key)
+	if prev == value {
+		return
+	}
+	// New value is different, update and journal the change
 	self.db.journal.append(storageChange{
 		account:  &self.address,
 		key:      key,
 		prevalue: prev,
 	})
-	if _, isSet := self.originalValue[key]; !isSet {
-		// original value has not been set, so set it now
-		self.originalValue[key] = prev
-	}
 	self.setState(key, value)
 }
 
 func (self *stateObject) setState(key, value common.Hash) {
-	self.cachedStorage[key] = value
 	self.dirtyStorage[key] = value
 }
 
@@ -218,6 +219,13 @@ func (self *stateObject) updateTrie(db Database) Trie {
 	tr := self.getTrie(db)
 	for key, value := range self.dirtyStorage {
 		delete(self.dirtyStorage, key)
+
+		// Skip noop changes, persist actual changes
+		if value == self.originStorage[key] {
+			continue
+		}
+		self.originStorage[key] = value
+
 		if (value == common.Hash{}) {
 			self.setError(tr.TryDelete(key[:]))
 			continue
@@ -226,10 +234,6 @@ func (self *stateObject) updateTrie(db Database) Trie {
 		v, _ := rlp.EncodeToBytes(bytes.TrimLeft(value[:], "\x00"))
 		self.setError(tr.TryUpdate(key[:], v))
 	}
-	// Clean the map containing 'original' value of storage entries
-	for k, _ := range self.originalValue {
-		delete(self.originalValue, k)
-	}
 	return tr
 }
 
@@ -299,8 +303,7 @@ func (self *stateObject) deepCopy(db *StateDB) *stateObject {
 	}
 	stateObject.code = self.code
 	stateObject.dirtyStorage = self.dirtyStorage.Copy()
-	stateObject.cachedStorage = self.dirtyStorage.Copy()
-	stateObject.originalValue = self.originalValue.Copy()
+	stateObject.originStorage = self.originStorage.Copy()
 	stateObject.suicided = self.suicided
 	stateObject.dirtyCode = self.dirtyCode
 	stateObject.deleted = self.deleted

core/state/state_test.go

@@ -96,11 +96,15 @@ func (s *StateSuite) TestNull(c *checker.C) {
 	s.state.CreateAccount(address)
 	//value := common.FromHex("0x823140710bf13990e4500136726d8b55")
 	var value common.Hash
+
 	s.state.SetState(address, common.Hash{}, value)
 	s.state.Commit(false)
-	value = s.state.GetState(address, common.Hash{})
-	if value != (common.Hash{}) {
-		c.Errorf("expected empty hash. got %x", value)
+
+	if value := s.state.GetState(address, common.Hash{}); value != (common.Hash{}) {
+		c.Errorf("expected empty current value, got %x", value)
+	}
+	if value := s.state.GetCommittedState(address, common.Hash{}); value != (common.Hash{}) {
+		c.Errorf("expected empty committed value, got %x", value)
 	}
 }
 
@@ -110,20 +114,24 @@ func (s *StateSuite) TestSnapshot(c *checker.C) {
 	data1 := common.BytesToHash([]byte{42})
 	data2 := common.BytesToHash([]byte{43})
 
+	// snapshot the genesis state
+	genesis := s.state.Snapshot()
+
 	// set initial state object value
 	s.state.SetState(stateobjaddr, storageaddr, data1)
-	// get snapshot of current state
 	snapshot := s.state.Snapshot()
 
-	// set new state object value
+	// set a new state object value, revert it and ensure correct content
 	s.state.SetState(stateobjaddr, storageaddr, data2)
-	// restore snapshot
 	s.state.RevertToSnapshot(snapshot)
 
-	// get state storage value
-	res := s.state.GetState(stateobjaddr, storageaddr)
+	c.Assert(s.state.GetState(stateobjaddr, storageaddr), checker.DeepEquals, data1)
+	c.Assert(s.state.GetCommittedState(stateobjaddr, storageaddr), checker.DeepEquals, common.Hash{})
 
-	c.Assert(data1, checker.DeepEquals, res)
+	// revert up to the genesis state and ensure correct content
+	s.state.RevertToSnapshot(genesis)
+	c.Assert(s.state.GetState(stateobjaddr, storageaddr), checker.DeepEquals, common.Hash{})
+	c.Assert(s.state.GetCommittedState(stateobjaddr, storageaddr), checker.DeepEquals, common.Hash{})
 }
 
 func (s *StateSuite) TestSnapshotEmpty(c *checker.C) {
@@ -208,24 +216,30 @@ func compareStateObjects(so0, so1 *stateObject, t *testing.T) {
 		t.Fatalf("Code mismatch: have %v, want %v", so0.code, so1.code)
 	}
 
-	if len(so1.cachedStorage) != len(so0.cachedStorage) {
-		t.Errorf("Storage size mismatch: have %d, want %d", len(so1.cachedStorage), len(so0.cachedStorage))
+	if len(so1.dirtyStorage) != len(so0.dirtyStorage) {
+		t.Errorf("Dirty storage size mismatch: have %d, want %d", len(so1.dirtyStorage), len(so0.dirtyStorage))
 	}
-	for k, v := range so1.cachedStorage {
-		if so0.cachedStorage[k] != v {
-			t.Errorf("Storage key %x mismatch: have %v, want %v", k, so0.cachedStorage[k], v)
+	for k, v := range so1.dirtyStorage {
+		if so0.dirtyStorage[k] != v {
+			t.Errorf("Dirty storage key %x mismatch: have %v, want %v", k, so0.dirtyStorage[k], v)
 		}
 	}
-	for k, v := range so0.cachedStorage {
-		if so1.cachedStorage[k] != v {
-			t.Errorf("Storage key %x mismatch: have %v, want none.", k, v)
+	for k, v := range so0.dirtyStorage {
+		if so1.dirtyStorage[k] != v {
+			t.Errorf("Dirty storage key %x mismatch: have %v, want none.", k, v)
 		}
 	}
-
-	if so0.suicided != so1.suicided {
-		t.Fatalf("suicided mismatch: have %v, want %v", so0.suicided, so1.suicided)
+	if len(so1.originStorage) != len(so0.originStorage) {
+		t.Errorf("Origin storage size mismatch: have %d, want %d", len(so1.originStorage), len(so0.originStorage))
+	}
+	for k, v := range so1.originStorage {
+		if so0.originStorage[k] != v {
+			t.Errorf("Origin storage key %x mismatch: have %v, want %v", k, so0.originStorage[k], v)
+		}
 	}
-	if so0.deleted != so1.deleted {
-		t.Fatalf("Deleted mismatch: have %v, want %v", so0.deleted, so1.deleted)
+	for k, v := range so0.originStorage {
+		if so1.originStorage[k] != v {
+			t.Errorf("Origin storage key %x mismatch: have %v, want none.", k, v)
+		}
 	}
 }

core/state/statedb.go

@@ -247,18 +247,20 @@ func (self *StateDB) GetCodeHash(addr common.Address) common.Hash {
 	return common.BytesToHash(stateObject.CodeHash())
 }
 
-func (self *StateDB) GetState(addr common.Address, bhash common.Hash) 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)
 	if stateObject != nil {
-		return stateObject.GetState(self.db, bhash)
+		return stateObject.GetState(self.db, hash)
 	}
 	return common.Hash{}
 }
 
-func (self *StateDB) GetStateOriginal(addr common.Address, bhash common.Hash) common.Hash {
+// 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)
 	if stateObject != nil {
-		return stateObject.GetOriginalStateValue(self.db, bhash)
+		return stateObject.GetCommittedState(self.db, hash)
 	}
 	return common.Hash{}
 }
@@ -454,19 +456,14 @@ func (db *StateDB) ForEachStorage(addr common.Address, cb func(key, value common
 	if so == nil {
 		return
 	}
-
-	// When iterating over the storage check the cache first
-	for h, value := range so.cachedStorage {
-		cb(h, value)
-	}
-
 	it := trie.NewIterator(so.getTrie(db.db).NodeIterator(nil))
 	for it.Next() {
-		// ignore cached values
 		key := common.BytesToHash(db.trie.GetKey(it.Key))
-		if _, ok := so.cachedStorage[key]; !ok {
-			cb(key, common.BytesToHash(it.Value))
+		if value, dirty := so.dirtyStorage[key]; dirty {
+			cb(key, value)
+			continue
 		}
+		cb(key, common.BytesToHash(it.Value))
 	}
 }
 

core/state/statedb_test.go

@@ -381,11 +381,11 @@ func (test *snapshotTest) checkEqual(state, checkstate *StateDB) error {
 		checkeq("GetCodeSize", state.GetCodeSize(addr), checkstate.GetCodeSize(addr))
 		// Check storage.
 		if obj := state.getStateObject(addr); obj != nil {
-			state.ForEachStorage(addr, func(key, val common.Hash) bool {
-				return checkeq("GetState("+key.Hex()+")", val, checkstate.GetState(addr, key))
+			state.ForEachStorage(addr, func(key, value common.Hash) bool {
+				return checkeq("GetState("+key.Hex()+")", checkstate.GetState(addr, key), value)
 			})
-			checkstate.ForEachStorage(addr, func(key, checkval common.Hash) bool {
-				return checkeq("GetState("+key.Hex()+")", state.GetState(addr, key), checkval)
+			checkstate.ForEachStorage(addr, func(key, value common.Hash) bool {
+				return checkeq("GetState("+key.Hex()+")", checkstate.GetState(addr, key), value)
 			})
 		}
 		if err != nil {