024d41d0c2
Removed exported statedb object accessors, reducing the chance for nasty bugs to creep in. It's also ugly and unnecessary to have these methods.
297 lines
8.1 KiB
Go
297 lines
8.1 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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"errors"
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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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errInsufficientBalanceForGas = errors.New("insufficient balance to pay for gas")
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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 uint64
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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.StateDB
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evm *vm.EVM
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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
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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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CheckNonce() bool
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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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//
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// TODO convert to uint64
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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.SetUint64(params.TxGasContractCreation)
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} else {
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igas.SetUint64(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, new(big.Int).SetUint64(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, new(big.Int).SetUint64(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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// NewStateTransition initialises and returns a new state transition object.
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func NewStateTransition(evm *vm.EVM, msg Message, gp *GasPool) *StateTransition {
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return &StateTransition{
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gp: gp,
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evm: evm,
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msg: msg,
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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: evm.StateDB,
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}
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}
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// ApplyMessage computes the new state by applying the given message
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// against the old state within the environment.
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//
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// ApplyMessage returns the bytes returned by any EVM execution (if it took place),
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// the gas used (which includes gas refunds) and an error if it failed. An error always
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// indicates a core error meaning that the message would always fail for that particular
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// state and would never be accepted within a block.
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func ApplyMessage(evm *vm.EVM, msg Message, gp *GasPool) ([]byte, *big.Int, error) {
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st := NewStateTransition(evm, msg, gp)
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ret, _, gasUsed, err := st.TransitionDb()
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return ret, gasUsed, err
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}
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func (self *StateTransition) from() vm.AccountRef {
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f := self.msg.From()
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if !self.state.Exist(f) {
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self.state.CreateAccount(f)
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}
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return vm.AccountRef(f)
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}
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func (self *StateTransition) to() vm.AccountRef {
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if self.msg == nil {
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return vm.AccountRef{}
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}
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to := self.msg.To()
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if to == nil {
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return vm.AccountRef{} // contract creation
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}
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reference := vm.AccountRef(*to)
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if !self.state.Exist(*to) {
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self.state.CreateAccount(*to)
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}
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return reference
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}
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func (self *StateTransition) useGas(amount uint64) error {
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if self.gas < amount {
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return vm.ErrOutOfGas
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}
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self.gas -= amount
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return nil
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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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if mgas.BitLen() > 64 {
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return vm.ErrOutOfGas
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}
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mgval := new(big.Int).Mul(mgas, self.gasPrice)
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var (
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state = self.state
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sender = self.from()
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)
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if state.GetBalance(sender.Address()).Cmp(mgval) < 0 {
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return errInsufficientBalanceForGas
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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.gas += mgas.Uint64()
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self.initialGas.Set(mgas)
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state.SubBalance(sender.Address(), 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 := self.from()
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// Make sure this transaction's nonce is correct
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if msg.CheckNonce() {
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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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}
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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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// TransitionDb will transition the state by applying the current message and returning the result
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// including the required gas for the operation as well as the used gas. It returns an error if it
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// failed. An error indicates a consensus issue.
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func (self *StateTransition) TransitionDb() (ret []byte, requiredGas, 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 := self.evm.ChainConfig().IsHomestead(self.evm.BlockNumber)
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contractCreation := MessageCreatesContract(msg)
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// Pay intrinsic gas
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// TODO convert to uint64
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intrinsicGas := IntrinsicGas(self.data, contractCreation, homestead)
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if intrinsicGas.BitLen() > 64 {
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return nil, nil, nil, InvalidTxError(vm.ErrOutOfGas)
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}
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if err = self.useGas(intrinsicGas.Uint64()); err != nil {
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return nil, nil, nil, InvalidTxError(err)
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}
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var (
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evm = self.evm
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// vm errors do not effect consensus and are therefor
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// not assigned to err, except for insufficient balance
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// error.
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vmerr error
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)
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if contractCreation {
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ret, _, self.gas, vmerr = evm.Create(sender, self.data, self.gas, self.value)
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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, self.gas, vmerr = evm.Call(sender, self.to().Address(), self.data, self.gas, self.value)
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}
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if vmerr != nil {
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glog.V(logger.Debug).Infoln("vm returned with error:", err)
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// The only possible consensus-error would be if there wasn't
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// sufficient balance to make the transfer happen. The first
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// balance transfer may never fail.
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if vmerr == vm.ErrInsufficientBalance {
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return nil, nil, nil, InvalidTxError(vmerr)
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}
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}
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requiredGas = new(big.Int).Set(self.gasUsed())
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self.refundGas()
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self.state.AddBalance(self.evm.Coinbase, new(big.Int).Mul(self.gasUsed(), self.gasPrice))
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return ret, requiredGas, 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(new(big.Int).SetUint64(self.gas), self.gasPrice)
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self.state.AddBalance(sender.Address(), 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 += refund.Uint64()
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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(new(big.Int).SetUint64(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, new(big.Int).SetUint64(self.gas))
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}
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