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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/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"
)
// The default, always homestead, rule set for the vm env
type ruleSet struct{}
func (ruleSet) IsHomestead(*big.Int) bool { return true }
// Config is a basic type specifying certain configuration flags for running
// the EVM.
type Config struct {
RuleSet vm.RuleSet
Difficulty *big.Int
Origin common.Address
Coinbase common.Address
BlockNumber *big.Int
Time *big.Int
GasLimit *big.Int
GasPrice *big.Int
Value *big.Int
DisableJit bool // "disable" so it's enabled by default
Debug bool
State *state.StateDB
GetHashFn func(n uint64) common.Hash
}
// sets defaults on the config
func setDefaults(cfg *Config) {
if cfg.RuleSet == nil {
cfg.RuleSet = ruleSet{}
}
if cfg.Difficulty == nil {
cfg.Difficulty = new(big.Int)
}
if cfg.Time == nil {
cfg.Time = big.NewInt(time.Now().Unix())
}
if cfg.GasLimit == nil {
cfg.GasLimit = new(big.Int).Set(common.MaxBig)
}
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{}, db)
}
var (
vmenv = NewEnv(cfg, cfg.State)
sender = cfg.State.CreateAccount(cfg.Origin)
receiver = cfg.State.CreateAccount(common.StringToAddress("contract"))
)
// set the receiver's (the executing contract) code for execution.
receiver.SetCode(code)
// Call the code with the given configuration.
ret, err := vmenv.Call(
sender,
receiver.Address(),
input,
cfg.GasLimit,
cfg.GasPrice,
cfg.Value,
)
return ret, cfg.State, 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, error) {
setDefaults(cfg)
vmenv := NewEnv(cfg, cfg.State)
sender := cfg.State.GetOrNewStateObject(cfg.Origin)
// Call the code with the given configuration.
ret, err := vmenv.Call(
sender,
address,
input,
cfg.GasLimit,
cfg.GasPrice,
cfg.Value,
)
return ret, err
}
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