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// Copyright 2015 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 runtime
import (
"math"
"math/big"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/state"
"github.com/ethereum/go-ethereum/core/vm"
"github.com/ethereum/go-ethereum/crypto"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/params"
)
// Config is a basic type specifying certain configuration flags for running
// the EVM.
type Config struct {
ChainConfig *params.ChainConfig
Difficulty *big.Int
Origin common.Address
Coinbase common.Address
BlockNumber *big.Int
Time *big.Int
GasLimit uint64
GasPrice *big.Int
Value *big.Int
DisableJit bool // "disable" so it's enabled by default
Debug bool
EVMConfig vm.Config
State *state.StateDB
GetHashFn func(n uint64) common.Hash
}
// sets defaults on the config
func setDefaults(cfg *Config) {
if cfg.ChainConfig == nil {
cfg.ChainConfig = ¶ms.ChainConfig{
ChainId: big.NewInt(1),
HomesteadBlock: new(big.Int),
DAOForkBlock: new(big.Int),
DAOForkSupport: false,
EIP150Block: new(big.Int),
EIP155Block: new(big.Int),
EIP158Block: new(big.Int),
}
}
if cfg.Difficulty == nil {
cfg.Difficulty = new(big.Int)
}
if cfg.Time == nil {
cfg.Time = big.NewInt(time.Now().Unix())
}
if cfg.GasLimit == 0 {
cfg.GasLimit = math.MaxUint64
}
if cfg.GasPrice == nil {
cfg.GasPrice = new(big.Int)
}
if cfg.Value == nil {
cfg.Value = new(big.Int)
}
if cfg.BlockNumber == nil {
cfg.BlockNumber = new(big.Int)
}
if cfg.GetHashFn == nil {
cfg.GetHashFn = func(n uint64) common.Hash {
return common.BytesToHash(crypto.Keccak256([]byte(new(big.Int).SetUint64(n).String())))
}
}
}
// Execute executes the code using the input as call data during the execution.
// It returns the EVM's return value, the new state and an error if it failed.
//
// Executes sets up a in memory, temporarily, environment for the execution of
// the given code. It enabled the JIT by default and make sure that it's restored
// to it's original state afterwards.
func Execute(code, input []byte, cfg *Config) ([]byte, *state.StateDB, error) {
if cfg == nil {
cfg = new(Config)
}
setDefaults(cfg)
if cfg.State == nil {
db, _ := ethdb.NewMemDatabase()
cfg.State, _ = state.New(common.Hash{}, state.NewDatabase(db))
}
var (
address = common.StringToAddress("contract")
vmenv = NewEnv(cfg)
sender = vm.AccountRef(cfg.Origin)
)
cfg.State.CreateAccount(address)
// set the receiver's (the executing contract) code for execution.
cfg.State.SetCode(address, code)
// Call the code with the given configuration.
ret, _, err := vmenv.Call(
sender,
common.StringToAddress("contract"),
input,
cfg.GasLimit,
cfg.Value,
)
return ret, cfg.State, err
}
// Create executes the code using the EVM create method
func Create(input []byte, cfg *Config) ([]byte, common.Address, uint64, error) {
if cfg == nil {
cfg = new(Config)
}
setDefaults(cfg)
if cfg.State == nil {
db, _ := ethdb.NewMemDatabase()
cfg.State, _ = state.New(common.Hash{}, state.NewDatabase(db))
}
var (
vmenv = NewEnv(cfg)
sender = vm.AccountRef(cfg.Origin)
)
// Call the code with the given configuration.
code, address, leftOverGas, err := vmenv.Create(
sender,
input,
cfg.GasLimit,
cfg.Value,
)
return code, address, leftOverGas, err
}
// Call executes the code given by the contract's address. It will return the
// EVM's return value or an error if it failed.
//
// Call, unlike Execute, requires a config and also requires the State field to
// be set.
func Call(address common.Address, input []byte, cfg *Config) ([]byte, uint64, error) {
setDefaults(cfg)
vmenv := NewEnv(cfg)
sender := cfg.State.GetOrNewStateObject(cfg.Origin)
// Call the code with the given configuration.
ret, leftOverGas, err := vmenv.Call(
sender,
address,
input,
cfg.GasLimit,
cfg.Value,
)
return ret, leftOverGas, err
}
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