287 lines
7.2 KiB
Go
287 lines
7.2 KiB
Go
// Copyright 2014 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package core
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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/common"
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"github.com/ethereum/go-ethereum/core/vm"
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"github.com/ethereum/go-ethereum/logger"
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"github.com/ethereum/go-ethereum/logger/glog"
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"github.com/ethereum/go-ethereum/params"
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)
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var (
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Big0 = big.NewInt(0)
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)
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/*
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The State Transitioning Model
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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 gas
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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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gp *GasPool
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msg Message
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gas, gasPrice *big.Int
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initialGas *big.Int
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value *big.Int
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data []byte
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state vm.Database
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env vm.Environment
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}
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// Message represents a message sent to a contract.
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type Message interface {
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From() (common.Address, error)
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FromFrontier() (common.Address, error)
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To() *common.Address
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GasPrice() *big.Int
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Gas() *big.Int
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Value() *big.Int
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Nonce() uint64
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Data() []byte
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}
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func MessageCreatesContract(msg Message) bool {
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return msg.To() == nil
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}
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// IntrinsicGas computes the 'intrinsic gas' for a message
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// with the given data.
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func IntrinsicGas(data []byte, contractCreation, homestead bool) *big.Int {
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igas := new(big.Int)
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if contractCreation && homestead {
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igas.Set(params.TxGasContractCreation)
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} else {
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igas.Set(params.TxGas)
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}
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if len(data) > 0 {
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var nz int64
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for _, byt := range data {
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if byt != 0 {
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nz++
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}
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}
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m := big.NewInt(nz)
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m.Mul(m, params.TxDataNonZeroGas)
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igas.Add(igas, m)
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m.SetInt64(int64(len(data)) - nz)
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m.Mul(m, params.TxDataZeroGas)
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igas.Add(igas, m)
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}
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return igas
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}
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func ApplyMessage(env vm.Environment, msg Message, gp *GasPool) ([]byte, *big.Int, error) {
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var st = StateTransition{
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gp: gp,
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env: env,
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msg: msg,
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gas: new(big.Int),
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gasPrice: msg.GasPrice(),
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initialGas: new(big.Int),
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value: msg.Value(),
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data: msg.Data(),
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state: env.Db(),
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}
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return st.transitionDb()
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}
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func (self *StateTransition) from() (vm.Account, error) {
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var (
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f common.Address
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err error
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)
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if params.IsHomestead(self.env.BlockNumber()) {
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f, err = self.msg.From()
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} else {
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f, err = self.msg.FromFrontier()
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}
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if err != nil {
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return nil, err
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}
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if !self.state.Exist(f) {
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return self.state.CreateAccount(f), nil
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}
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return self.state.GetAccount(f), nil
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}
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func (self *StateTransition) to() vm.Account {
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if self.msg == nil {
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return nil
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}
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to := self.msg.To()
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if to == nil {
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return nil // contract creation
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}
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if !self.state.Exist(*to) {
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return self.state.CreateAccount(*to)
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}
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return self.state.GetAccount(*to)
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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 vm.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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mgas := self.msg.Gas()
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mgval := new(big.Int).Mul(mgas, self.gasPrice)
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sender, err := self.from()
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if err != nil {
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return err
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}
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if sender.Balance().Cmp(mgval) < 0 {
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return fmt.Errorf("insufficient ETH for gas (%x). Req %v, has %v", sender.Address().Bytes()[:4], mgval, sender.Balance())
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}
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if err = self.gp.SubGas(mgas); err != nil {
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return err
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}
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self.addGas(mgas)
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self.initialGas.Set(mgas)
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sender.SubBalance(mgval)
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return nil
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}
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func (self *StateTransition) preCheck() (err error) {
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msg := self.msg
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sender, err := self.from()
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if err != nil {
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return err
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}
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// Make sure this transaction's nonce is correct
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//if sender.Nonce() != msg.Nonce() {
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if n := self.state.GetNonce(sender.Address()); n != msg.Nonce() {
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return NonceError(msg.Nonce(), n)
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}
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// Pre-pay gas
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if err = self.buyGas(); err != nil {
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if IsGasLimitErr(err) {
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return err
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}
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return InvalidTxError(err)
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}
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return nil
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}
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func (self *StateTransition) transitionDb() (ret []byte, usedGas *big.Int, err error) {
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if err = self.preCheck(); err != nil {
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return
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}
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msg := self.msg
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sender, _ := self.from() // err checked in preCheck
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homestead := params.IsHomestead(self.env.BlockNumber())
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contractCreation := MessageCreatesContract(msg)
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// Pay intrinsic gas
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if err = self.useGas(IntrinsicGas(self.data, contractCreation, homestead)); err != nil {
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return nil, nil, InvalidTxError(err)
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}
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vmenv := self.env
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//var addr common.Address
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if contractCreation {
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ret, _, err = vmenv.Create(sender, self.data, self.gas, self.gasPrice, self.value)
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if homestead && err == vm.CodeStoreOutOfGasError {
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self.gas = Big0
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}
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if err != nil {
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ret = nil
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glog.V(logger.Core).Infoln("VM create err:", err)
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}
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} else {
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// Increment the nonce for the next transaction
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self.state.SetNonce(sender.Address(), self.state.GetNonce(sender.Address())+1)
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ret, err = vmenv.Call(sender, self.to().Address(), self.data, self.gas, self.gasPrice, self.value)
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if err != nil {
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glog.V(logger.Core).Infoln("VM call err:", err)
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}
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}
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if err != nil && IsValueTransferErr(err) {
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return nil, nil, InvalidTxError(err)
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}
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// We aren't interested in errors here. Errors returned by the VM are non-consensus errors and therefor shouldn't bubble up
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if err != nil {
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err = nil
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}
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if vm.Debug {
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vm.StdErrFormat(vmenv.StructLogs())
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}
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self.refundGas()
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self.state.AddBalance(self.env.Coinbase(), new(big.Int).Mul(self.gasUsed(), self.gasPrice))
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return ret, self.gasUsed(), err
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}
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func (self *StateTransition) refundGas() {
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// Return eth for remaining gas to the sender account,
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// exchanged at the original rate.
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sender, _ := self.from() // err already checked
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remaining := new(big.Int).Mul(self.gas, self.gasPrice)
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sender.AddBalance(remaining)
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// Apply refund counter, capped to half of the used gas.
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uhalf := remaining.Div(self.gasUsed(), common.Big2)
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refund := common.BigMin(uhalf, self.state.GetRefund())
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self.gas.Add(self.gas, refund)
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self.state.AddBalance(sender.Address(), refund.Mul(refund, self.gasPrice))
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// Also return remaining gas to the block gas counter so it is
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// available for the next transaction.
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self.gp.AddGas(self.gas)
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}
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func (self *StateTransition) gasUsed() *big.Int {
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return new(big.Int).Sub(self.initialGas, self.gas)
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}
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