Refactoring state transitioning

1 files changed, 178 insertions, 157 deletions

diff --git a/ethchain/state_manager.go b/ethchain/state_manager.go
index 7b44ba3b8..f44afecac 100644
--- a/ethchain/state_manager.go
+++ b/ethchain/state_manager.go
@@ -108,8 +108,86 @@ func (sm *StateManager) MakeStateObject(state *State, tx *Transaction) *StateObj
 	return nil
 }
 
-func (self *StateManager) ProcessTransaction(tx *Transaction, coinbase *StateObject, state *State, toContract bool) (gas *big.Int, err error) {
-	fmt.Printf("state root before update %x\n", state.Root())
+type StateTransition struct {
+	coinbase []byte
+	tx       *Transaction
+	gas      *big.Int
+	state    *State
+	block    *Block
+
+	cb, rec, sen *StateObject
+}
+
+func NewStateTransition(coinbase []byte, gas *big.Int, tx *Transaction, state *State, block *Block) *StateTransition {
+	return &StateTransition{coinbase, tx, new(big.Int), state, block, nil, nil, nil}
+}
+
+func (self *StateTransition) Coinbase() *StateObject {
+	if self.cb != nil {
+		return self.cb
+	}
+
+	self.cb = self.state.GetAccount(self.coinbase)
+	return self.cb
+}
+func (self *StateTransition) Sender() *StateObject {
+	if self.sen != nil {
+		return self.sen
+	}
+
+	self.sen = self.state.GetAccount(self.tx.Sender())
+	return self.sen
+}
+func (self *StateTransition) Receiver() *StateObject {
+	if self.tx.CreatesContract() {
+		return nil
+	}
+
+	if self.rec != nil {
+		return self.rec
+	}
+
+	self.rec = self.state.GetAccount(self.tx.Recipient)
+	return self.rec
+}
+
+func (self *StateTransition) UseGas(amount *big.Int) error {
+	if self.gas.Cmp(amount) < 0 {
+		return OutOfGasError()
+	}
+	self.gas.Sub(self.gas, amount)
+
+	return nil
+}
+
+func (self *StateTransition) AddGas(amount *big.Int) {
+	self.gas.Add(self.gas, amount)
+}
+
+func (self *StateTransition) BuyGas() error {
+	var err error
+
+	sender := self.Sender()
+	if sender.Amount.Cmp(self.tx.GasValue()) < 0 {
+		return fmt.Errorf("Insufficient funds to pre-pay gas. Req %v, has %v", self.tx.GasValue(), self.tx.Value)
+	}
+
+	coinbase := self.Coinbase()
+	err = coinbase.BuyGas(self.tx.Gas, self.tx.GasPrice)
+	if err != nil {
+		return err
+	}
+	self.state.UpdateStateObject(coinbase)
+
+	self.AddGas(self.tx.Gas)
+	sender.SubAmount(self.tx.GasValue())
+
+	return nil
+}
+
+func (self *StateManager) TransitionState(st *StateTransition) (err error) {
+	//snapshot := st.state.Snapshot()
+
 	defer func() {
 		if r := recover(); r != nil {
 			ethutil.Config.Log.Infoln(r)
@@ -117,173 +195,144 @@ func (self *StateManager) ProcessTransaction(tx *Transaction, coinbase *StateObj
 		}
 	}()
 
-	gas = new(big.Int)
-	addGas := func(g *big.Int) { gas.Add(gas, g) }
-	addGas(GasTx)
-
-	// Get the sender
-	sender := state.GetAccount(tx.Sender())
+	var (
+		tx       = st.tx
+		sender   = st.Sender()
+		receiver *StateObject
+	)
 
 	if sender.Nonce != tx.Nonce {
-		err = NonceError(tx.Nonce, sender.Nonce)
-		return
+		return NonceError(tx.Nonce, sender.Nonce)
 	}
 
 	sender.Nonce += 1
 	defer func() {
-		//state.UpdateStateObject(sender)
 		// Notify all subscribers
 		self.Ethereum.Reactor().Post("newTx:post", tx)
 	}()
 
-	txTotalBytes := big.NewInt(int64(len(tx.Data)))
-	txTotalBytes.Div(txTotalBytes, ethutil.Big32)
-	addGas(new(big.Int).Mul(txTotalBytes, GasSStore))
+	if err = st.BuyGas(); err != nil {
+		return err
+	}
 
-	rGas := new(big.Int).Set(gas)
-	rGas.Mul(gas, tx.GasPrice)
+	receiver = st.Receiver()
 
-	// Make sure there's enough in the sender's account. Having insufficient
-	// funds won't invalidate this transaction but simple ignores it.
-	totAmount := new(big.Int).Add(tx.Value, rGas)
-	if sender.Amount.Cmp(totAmount) < 0 {
-		state.UpdateStateObject(sender)
-		err = fmt.Errorf("[TXPL] Insufficient amount in sender's (%x) account", tx.Sender())
-		return
+	if err = st.UseGas(GasTx); err != nil {
+		return err
 	}
 
-	coinbase.BuyGas(gas, tx.GasPrice)
-	state.UpdateStateObject(coinbase)
-
-	// Get the receiver
-	receiver := state.GetAccount(tx.Recipient)
+	dataPrice := big.NewInt(int64(len(tx.Data)))
+	dataPrice.Mul(dataPrice, GasData)
+	if err = st.UseGas(dataPrice); err != nil {
+		return err
+	}
 
-	// Send Tx to self
-	if bytes.Compare(tx.Recipient, tx.Sender()) == 0 {
-		// Subtract the fee
-		sender.SubAmount(rGas)
-	} else {
-		// Subtract the amount from the senders account
-		sender.SubAmount(totAmount)
+	if receiver == nil { // Contract
+		receiver = self.MakeStateObject(st.state, tx)
+		if receiver == nil {
+			return fmt.Errorf("ERR. Unable to create contract with transaction %v", tx)
+		}
+	}
 
-		// Add the amount to receivers account which should conclude this transaction
-		receiver.AddAmount(tx.Value)
-		state.UpdateStateObject(receiver)
+	if err = self.transferValue(st, sender, receiver); err != nil {
+		return err
 	}
 
-	state.UpdateStateObject(sender)
+	if tx.CreatesContract() {
+		fmt.Println(Disassemble(receiver.Init()))
+		// Evaluate the initialization script
+		// and use the return value as the
+		// script section for the state object.
+		//script, gas, err = sm.Eval(state, contract.Init(), contract, tx, block)
+		code, err := self.Eval(st, receiver.Init(), receiver)
+		if err != nil {
+			return fmt.Errorf("Error during init script run %v", err)
+		}
 
-	ethutil.Config.Log.Infof("[TXPL] Processed Tx %x\n", tx.Hash())
+		receiver.script = code
+	}
 
-	return
+	st.state.UpdateStateObject(sender)
+	st.state.UpdateStateObject(receiver)
+
+	return nil
 }
 
-// Apply transactions uses the transaction passed to it and applies them onto
-// the current processing state.
-func (sm *StateManager) ApplyTransactions(coinbase []byte, state *State, block *Block, txs []*Transaction) ([]*Receipt, []*Transaction) {
-	// Process each transaction/contract
-	var receipts []*Receipt
-	var validTxs []*Transaction
-	var ignoredTxs []*Transaction // Transactions which go over the gasLimit
+func (self *StateManager) transferValue(st *StateTransition, sender, receiver *StateObject) error {
+	if sender.Amount.Cmp(st.tx.Value) < 0 {
+		return fmt.Errorf("Insufficient funds to transfer value. Req %v, has %v", st.tx.Value, sender.Amount)
+	}
+
+	// Subtract the amount from the senders account
+	sender.SubAmount(st.tx.Value)
+	// Add the amount to receivers account which should conclude this transaction
+	receiver.AddAmount(st.tx.Value)
 
-	totalUsedGas := big.NewInt(0)
+	ethutil.Config.Log.Debugf("%x => %x (%v) %x\n", sender.Address()[:4], receiver.Address()[:4], st.tx.Value, st.tx.Hash())
 
-	for _, tx := range txs {
-		usedGas, err := sm.ApplyTransaction(coinbase, state, block, tx)
+	return nil
+}
+
+func (self *StateManager) ProcessTransactions(coinbase []byte, state *State, block, parent *Block, txs Transactions) (Receipts, Transactions, Transactions, error) {
+	var (
+		receipts           Receipts
+		handled, unhandled Transactions
+		totalUsedGas       = big.NewInt(0)
+		err                error
+	)
+
+done:
+	for i, tx := range txs {
+		txGas := new(big.Int).Set(tx.Gas)
+		st := NewStateTransition(coinbase, tx.Gas, tx, state, block)
+		err = self.TransitionState(st)
 		if err != nil {
-			if IsNonceErr(err) {
-				continue
-			}
-			if IsGasLimitErr(err) {
-				ignoredTxs = append(ignoredTxs, tx)
-				// We need to figure out if we want to do something with thse txes
-				ethutil.Config.Log.Debugln("Gastlimit:", err)
+			switch {
+			case IsNonceErr(err):
+				err = nil // ignore error
 				continue
-			}
+			case IsGasLimitErr(err):
+				unhandled = txs[i:]
 
-			ethutil.Config.Log.Infoln(err)
+				break done
+			default:
+				ethutil.Config.Log.Infoln(err)
+			}
 		}
 
-		accumelative := new(big.Int).Set(totalUsedGas.Add(totalUsedGas, usedGas))
+		txGas.Sub(txGas, st.gas)
+		accumelative := new(big.Int).Set(totalUsedGas.Add(totalUsedGas, txGas))
 		receipt := &Receipt{tx, ethutil.CopyBytes(state.Root().([]byte)), accumelative}
 
 		receipts = append(receipts, receipt)
-		validTxs = append(validTxs, tx)
+		handled = append(handled, tx)
 	}
 
 	fmt.Println("################# MADE\n", receipts, "\n############################")
 
-	// Update the total gas used for the block (to be mined)
-	block.GasUsed = totalUsedGas
+	parent.GasUsed = totalUsedGas
 
-	return receipts, validTxs
+	return receipts, handled, unhandled, err
 }
 
-func (sm *StateManager) ApplyTransaction(coinbase []byte, state *State, block *Block, tx *Transaction) (totalGasUsed *big.Int, err error) {
-	/*
-		Applies transactions to the given state and creates new
-		state objects where needed.
-
-		If said objects needs to be created
-		run the initialization script provided by the transaction and
-		assume there's a return value. The return value will be set to
-		the script section of the state object.
-	*/
+func (self *StateManager) Eval(st *StateTransition, script []byte, context *StateObject) (ret []byte, err error) {
 	var (
-		addTotalGas = func(gas *big.Int) { totalGasUsed.Add(totalGasUsed, gas) }
-		gas         = new(big.Int)
-		script      []byte
+		tx        = st.tx
+		block     = st.block
+		initiator = st.Sender()
 	)
-	totalGasUsed = big.NewInt(0)
-	snapshot := state.Snapshot()
 
-	ca := state.GetAccount(coinbase)
-	// Apply the transaction to the current state
-	gas, err = sm.ProcessTransaction(tx, ca, state, false)
-	addTotalGas(gas)
-
-	if tx.CreatesContract() {
-		if err == nil {
-			// Create a new state object and the transaction
-			// as it's data provider.
-			contract := sm.MakeStateObject(state, tx)
-			if contract != nil {
-				fmt.Println(Disassemble(contract.Init()))
-				// Evaluate the initialization script
-				// and use the return value as the
-				// script section for the state object.
-				script, gas, err = sm.EvalScript(state, contract.Init(), contract, tx, block)
-				addTotalGas(gas)
-
-				if err != nil {
-					err = fmt.Errorf("[STATE] Error during init script run %v", err)
-					return
-				}
-				contract.script = script
-				state.UpdateStateObject(contract)
-			} else {
-				err = fmt.Errorf("[STATE] Unable to create contract")
-			}
-		} else {
-			err = fmt.Errorf("[STATE] contract creation tx: %v for sender %x", err, tx.Sender())
-		}
-	} else {
-		// Find the state object at the "recipient" address. If
-		// there's an object attempt to run the script.
-		stateObject := state.GetStateObject(tx.Recipient)
-		if err == nil && stateObject != nil && len(stateObject.Script()) > 0 {
-			_, gas, err = sm.EvalScript(state, stateObject.Script(), stateObject, tx, block)
-			addTotalGas(gas)
-		}
-	}
-
-	parent := sm.bc.GetBlock(block.PrevHash)
-	total := new(big.Int).Add(block.GasUsed, totalGasUsed)
-	limit := block.CalcGasLimit(parent)
-	if total.Cmp(limit) > 0 {
-		state.Revert(snapshot)
-		err = GasLimitError(total, limit)
-	}
+	closure := NewClosure(initiator, context, script, st.state, st.gas, tx.GasPrice)
+	vm := NewVm(st.state, self, RuntimeVars{
+		Origin:      initiator.Address(),
+		BlockNumber: block.BlockInfo().Number,
+		PrevHash:    block.PrevHash,
+		Coinbase:    block.Coinbase,
+		Time:        block.Time,
+		Diff:        block.Difficulty,
+		Value:       tx.Value,
+	})
+	ret, _, err = closure.Call(vm, tx.Data, nil)
 
 	return
 }
@@ -325,7 +374,8 @@ func (sm *StateManager) ProcessBlock(state *State, parent, block *Block, dontRea
 	fmt.Println(block.Receipts())
 
 	// Process the transactions on to current block
-	sm.ApplyTransactions(block.Coinbase, state, parent, block.Transactions())
+	//sm.ApplyTransactions(block.Coinbase, state, parent, block.Transactions())
+	sm.ProcessTransactions(block.Coinbase, state, block, parent, block.Transactions())
 
 	// Block validation
 	if err := sm.ValidateBlock(block); err != nil {
@@ -464,35 +514,6 @@ func (sm *StateManager) Stop() {
 	sm.bc.Stop()
 }
 
-func (sm *StateManager) EvalScript(state *State, script []byte, object *StateObject, tx *Transaction, block *Block) (ret []byte, gas *big.Int, err error) {
-	account := state.GetAccount(tx.Sender())
-
-	err = account.ConvertGas(tx.Gas, tx.GasPrice)
-	if err != nil {
-		ethutil.Config.Log.Debugln(err)
-		return
-	}
-
-	closure := NewClosure(account, object, script, state, tx.Gas, tx.GasPrice)
-	vm := NewVm(state, sm, RuntimeVars{
-		Origin:      account.Address(),
-		BlockNumber: block.BlockInfo().Number,
-		PrevHash:    block.PrevHash,
-		Coinbase:    block.Coinbase,
-		Time:        block.Time,
-		Diff:        block.Difficulty,
-		Value:       tx.Value,
-		//Price:       tx.GasPrice,
-	})
-	ret, gas, err = closure.Call(vm, tx.Data, nil)
-
-	// Update the account (refunds)
-	state.UpdateStateObject(account)
-	state.UpdateStateObject(object)
-
-	return
-}
-
 func (sm *StateManager) notifyChanges(state *State) {
 	for addr, stateObject := range state.manifest.objectChanges {
 		sm.Ethereum.Reactor().Post("object:"+addr, stateObject)