Merge eth-go repository into go-ethereum
mist, etheruem have been moved to cmd/
This commit is contained in:
Felix Lange
276
ethchain/state_transition.go
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276
ethchain/state_transition.go
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package ethchain
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import (
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"fmt"
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"math/big"
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"github.com/ethereum/go-ethereum/ethstate"
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"github.com/ethereum/go-ethereum/ethtrie"
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"github.com/ethereum/go-ethereum/ethutil"
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"github.com/ethereum/go-ethereum/vm"
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)
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/*
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* The State transitioning model
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*
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* A state transition is a change made when a transaction is applied to the current world state
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* The state transitioning model does all all the necessary work to work out a valid new state root.
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* 1) Nonce handling
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* 2) Pre pay / buy gas of the coinbase (miner)
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* 3) Create a new state object if the recipient is \0*32
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* 4) Value transfer
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* == If contract creation ==
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* 4a) Attempt to run transaction data
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* 4b) If valid, use result as code for the new state object
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* == end ==
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* 5) Run Script section
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* 6) Derive new state root
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*/
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type StateTransition struct {
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coinbase, receiver []byte
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tx *Transaction
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gas, gasPrice *big.Int
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value *big.Int
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data []byte
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state *ethstate.State
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block *Block
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cb, rec, sen *ethstate.StateObject
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}
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func NewStateTransition(coinbase *ethstate.StateObject, tx *Transaction, state *ethstate.State, block *Block) *StateTransition {
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return &StateTransition{coinbase.Address(), tx.Recipient, tx, new(big.Int), new(big.Int).Set(tx.GasPrice), tx.Value, tx.Data, state, block, coinbase, nil, nil}
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}
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func (self *StateTransition) Coinbase() *ethstate.StateObject {
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if self.cb != nil {
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return self.cb
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}
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self.cb = self.state.GetOrNewStateObject(self.coinbase)
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return self.cb
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}
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func (self *StateTransition) Sender() *ethstate.StateObject {
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if self.sen != nil {
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return self.sen
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}
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self.sen = self.state.GetOrNewStateObject(self.tx.Sender())
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return self.sen
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}
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func (self *StateTransition) Receiver() *ethstate.StateObject {
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if self.tx != nil && self.tx.CreatesContract() {
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return nil
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}
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if self.rec != nil {
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return self.rec
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}
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self.rec = self.state.GetOrNewStateObject(self.tx.Recipient)
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return self.rec
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}
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func (self *StateTransition) UseGas(amount *big.Int) error {
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if self.gas.Cmp(amount) < 0 {
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return OutOfGasError()
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}
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self.gas.Sub(self.gas, amount)
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return nil
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}
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func (self *StateTransition) AddGas(amount *big.Int) {
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self.gas.Add(self.gas, amount)
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}
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func (self *StateTransition) BuyGas() error {
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var err error
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sender := self.Sender()
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if sender.Balance().Cmp(self.tx.GasValue()) < 0 {
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return fmt.Errorf("Insufficient funds to pre-pay gas. Req %v, has %v", self.tx.GasValue(), sender.Balance())
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}
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coinbase := self.Coinbase()
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err = coinbase.BuyGas(self.tx.Gas, self.tx.GasPrice)
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if err != nil {
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return err
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}
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self.AddGas(self.tx.Gas)
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sender.SubAmount(self.tx.GasValue())
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return nil
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}
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func (self *StateTransition) RefundGas() {
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coinbase, sender := self.Coinbase(), self.Sender()
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coinbase.RefundGas(self.gas, self.tx.GasPrice)
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// Return remaining gas
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remaining := new(big.Int).Mul(self.gas, self.tx.GasPrice)
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sender.AddAmount(remaining)
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}
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func (self *StateTransition) preCheck() (err error) {
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var (
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tx = self.tx
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sender = self.Sender()
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)
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// Make sure this transaction's nonce is correct
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if sender.Nonce != tx.Nonce {
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return NonceError(tx.Nonce, sender.Nonce)
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}
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// Pre-pay gas / Buy gas of the coinbase account
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if err = self.BuyGas(); err != nil {
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return err
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}
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return nil
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}
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func (self *StateTransition) TransitionState() (err error) {
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statelogger.Debugf("(~) %x\n", self.tx.Hash())
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defer func() {
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if r := recover(); r != nil {
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statelogger.Infoln(r)
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err = fmt.Errorf("state transition err %v", r)
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}
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}()
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// XXX Transactions after this point are considered valid.
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if err = self.preCheck(); err != nil {
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return
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}
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var (
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tx = self.tx
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sender = self.Sender()
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receiver *ethstate.StateObject
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)
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defer self.RefundGas()
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// Increment the nonce for the next transaction
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sender.Nonce += 1
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// Transaction gas
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if err = self.UseGas(vm.GasTx); err != nil {
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return
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}
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// Pay data gas
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dataPrice := big.NewInt(int64(len(self.data)))
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dataPrice.Mul(dataPrice, vm.GasData)
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if err = self.UseGas(dataPrice); err != nil {
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return
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}
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if sender.Balance().Cmp(self.value) < 0 {
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return fmt.Errorf("Insufficient funds to transfer value. Req %v, has %v", self.value, sender.Balance)
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}
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var snapshot *ethstate.State
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// If the receiver is nil it's a contract (\0*32).
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if tx.CreatesContract() {
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// Subtract the (irreversible) amount from the senders account
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sender.SubAmount(self.value)
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snapshot = self.state.Copy()
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// Create a new state object for the contract
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receiver := MakeContract(tx, self.state)
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self.rec = receiver
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if receiver == nil {
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return fmt.Errorf("Unable to create contract")
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}
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// Add the amount to receivers account which should conclude this transaction
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receiver.AddAmount(self.value)
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} else {
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receiver = self.Receiver()
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// Subtract the amount from the senders account
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sender.SubAmount(self.value)
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// Add the amount to receivers account which should conclude this transaction
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receiver.AddAmount(self.value)
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snapshot = self.state.Copy()
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}
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msg := self.state.Manifest().AddMessage(ðstate.Message{
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To: receiver.Address(), From: sender.Address(),
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Input: self.tx.Data,
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Origin: sender.Address(),
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Block: self.block.Hash(), Timestamp: self.block.Time, Coinbase: self.block.Coinbase, Number: self.block.Number,
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Value: self.value,
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})
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// Process the init code and create 'valid' contract
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if IsContractAddr(self.receiver) {
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// Evaluate the initialization script
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// and use the return value as the
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// script section for the state object.
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self.data = nil
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code, err := self.Eval(msg, receiver.Init(), receiver)
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if err != nil {
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self.state.Set(snapshot)
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return fmt.Errorf("Error during init execution %v", err)
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}
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receiver.Code = code
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msg.Output = code
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} else {
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if len(receiver.Code) > 0 {
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ret, err := self.Eval(msg, receiver.Code, receiver)
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if err != nil {
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self.state.Set(snapshot)
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return fmt.Errorf("Error during code execution %v", err)
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}
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msg.Output = ret
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}
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}
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return
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}
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func (self *StateTransition) Eval(msg *ethstate.Message, script []byte, context *ethstate.StateObject) (ret []byte, err error) {
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var (
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transactor = self.Sender()
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state = self.state
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env = NewEnv(state, self.tx, self.block)
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callerClosure = vm.NewClosure(msg, transactor, context, script, self.gas, self.gasPrice)
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)
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//vm := vm.New(env, vm.Type(ethutil.Config.VmType))
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evm := vm.New(env, vm.DebugVmTy)
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ret, _, err = callerClosure.Call(evm, self.tx.Data)
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return
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}
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// Converts an transaction in to a state object
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func MakeContract(tx *Transaction, state *ethstate.State) *ethstate.StateObject {
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// Create contract if there's no recipient
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if tx.IsContract() {
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addr := tx.CreationAddress(state)
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contract := state.GetOrNewStateObject(addr)
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contract.InitCode = tx.Data
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contract.State = ethstate.New(ethtrie.New(ethutil.Config.Db, ""))
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return contract
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}
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return nil
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}
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