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// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package core
import (
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/params"
)
// Call executes within the given contract
func Call(env vm.Environment, caller vm.ContractRef, addr common.Address, input []byte, gas, gasPrice, value *big.Int) (ret []byte, err error) {
ret, _, err = exec(env, caller, &addr, &addr, input, env.Db().GetCode(addr), gas, gasPrice, value)
return ret, err
}
// CallCode executes the given address' code as the given contract address
func CallCode(env vm.Environment, caller vm.ContractRef, addr common.Address, input []byte, gas, gasPrice, value *big.Int) (ret []byte, err error) {
callerAddr := caller.Address()
ret, _, err = exec(env, caller, &callerAddr, &addr, input, env.Db().GetCode(addr), gas, gasPrice, value)
return ret, err
}
// DelegateCall is equivalent to CallCode except that sender and value propagates from parent scope to child scope
func DelegateCall(env vm.Environment, caller vm.ContractRef, addr common.Address, input []byte, gas, gasPrice *big.Int) (ret []byte, err error) {
callerAddr := caller.Address()
originAddr := env.Origin()
callerValue := caller.Value()
ret, _, err = execDelegateCall(env, caller, &originAddr, &callerAddr, &addr, input, env.Db().GetCode(addr), gas, gasPrice, callerValue)
return ret, err
}
// Create creates a new contract with the given code
func Create(env vm.Environment, caller vm.ContractRef, code []byte, gas, gasPrice, value *big.Int) (ret []byte, address common.Address, err error) {
ret, address, err = exec(env, caller, nil, nil, nil, code, gas, gasPrice, value)
// Here we get an error if we run into maximum stack depth,
// See: https://github.com/ethereum/yellowpaper/pull/131
// and YP definitions for CREATE instruction
if err != nil {
return nil, address, err
}
return ret, address, err
}
func exec(env vm.Environment, caller vm.ContractRef, address, codeAddr *common.Address, input, code []byte, gas, gasPrice, value *big.Int) (ret []byte, addr common.Address, err error) {
evm := vm.NewVm(env)
// Depth check execution. Fail if we're trying to execute above the
// limit.
if env.Depth() > int(params.CallCreateDepth.Int64()) {
caller.ReturnGas(gas, gasPrice)
return nil, common.Address{}, vm.DepthError
}
if !env.CanTransfer(caller.Address(), value) {
caller.ReturnGas(gas, gasPrice)
return nil, common.Address{}, ValueTransferErr("insufficient funds to transfer value. Req %v, has %v", value, env.Db().GetBalance(caller.Address()))
}
var createAccount bool
if address == nil {
// Create a new account on the state
nonce := env.Db().GetNonce(caller.Address())
env.Db().SetNonce(caller.Address(), nonce+1)
addr = crypto.CreateAddress(caller.Address(), nonce)
address = &addr
createAccount = true
}
snapshotPreTransfer := env.MakeSnapshot()
var (
from = env.Db().GetAccount(caller.Address())
to vm.Account
)
if createAccount {
to = env.Db().CreateAccount(*address)
} else {
if !env.Db().Exist(*address) {
to = env.Db().CreateAccount(*address)
} else {
to = env.Db().GetAccount(*address)
}
}
env.Transfer(from, to, value)
// initialise a new contract and set the code that is to be used by the
// EVM. The contract is a scoped environment for this execution context
// only.
contract := vm.NewContract(caller, to, value, gas, gasPrice)
contract.SetCallCode(codeAddr, code)
defer contract.Finalise()
ret, err = evm.Run(contract, input)
// if the contract creation ran successfully and no errors were returned
// calculate the gas required to store the code. If the code could not
// be stored due to not enough gas set an error and let it be handled
// by the error checking condition below.
if err == nil && createAccount {
dataGas := big.NewInt(int64(len(ret)))
dataGas.Mul(dataGas, params.CreateDataGas)
if contract.UseGas(dataGas) {
env.Db().SetCode(*address, ret)
} else {
err = vm.CodeStoreOutOfGasError
}
}
// When an error was returned by the EVM or when setting the creation code
// above we revert to the snapshot and consume any gas remaining. Additionally
// when we're in homestead this also counts for code storage gas errors.
if err != nil && (params.IsHomestead(env.BlockNumber()) || err != vm.CodeStoreOutOfGasError) {
contract.UseGas(contract.Gas)
env.SetSnapshot(snapshotPreTransfer)
}
return ret, addr, err
}
func execDelegateCall(env vm.Environment, caller vm.ContractRef, originAddr, toAddr, codeAddr *common.Address, input, code []byte, gas, gasPrice, value *big.Int) (ret []byte, addr common.Address, err error) {
evm := vm.NewVm(env)
// Depth check execution. Fail if we're trying to execute above the
// limit.
if env.Depth() > int(params.CallCreateDepth.Int64()) {
caller.ReturnGas(gas, gasPrice)
return nil, common.Address{}, vm.DepthError
}
snapshot := env.MakeSnapshot()
var to vm.Account
if !env.Db().Exist(*toAddr) {
to = env.Db().CreateAccount(*toAddr)
} else {
to = env.Db().GetAccount(*toAddr)
}
// Iinitialise a new contract and make initialise the delegate values
contract := vm.NewContract(caller, to, value, gas, gasPrice).AsDelegate()
contract.SetCallCode(codeAddr, code)
defer contract.Finalise()
ret, err = evm.Run(contract, input)
if err != nil {
contract.UseGas(contract.Gas)
env.SetSnapshot(snapshot)
}
return ret, addr, err
}
// generic transfer method
func Transfer(from, to vm.Account, amount *big.Int) {
from.SubBalance(amount)
to.AddBalance(amount)
}
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