201 lines
7.5 KiB
Go
201 lines
7.5 KiB
Go
// Copyright 2016 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 backends
|
|
|
|
import (
|
|
"math/big"
|
|
|
|
"github.com/ethereum/go-ethereum/accounts/abi/bind"
|
|
"github.com/ethereum/go-ethereum/common"
|
|
"github.com/ethereum/go-ethereum/core"
|
|
"github.com/ethereum/go-ethereum/core/state"
|
|
"github.com/ethereum/go-ethereum/core/types"
|
|
"github.com/ethereum/go-ethereum/core/vm"
|
|
"github.com/ethereum/go-ethereum/ethdb"
|
|
"github.com/ethereum/go-ethereum/event"
|
|
)
|
|
|
|
// Default chain configuration which sets homestead phase at block 0 (i.e. no frontier)
|
|
var chainConfig = &core.ChainConfig{HomesteadBlock: big.NewInt(0)}
|
|
|
|
// This nil assignment ensures compile time that SimulatedBackend implements bind.ContractBackend.
|
|
var _ bind.ContractBackend = (*SimulatedBackend)(nil)
|
|
|
|
// SimulatedBackend implements bind.ContractBackend, simulating a blockchain in
|
|
// the background. Its main purpose is to allow easily testing contract bindings.
|
|
type SimulatedBackend struct {
|
|
database ethdb.Database // In memory database to store our testing data
|
|
blockchain *core.BlockChain // Ethereum blockchain to handle the consensus
|
|
|
|
pendingBlock *types.Block // Currently pending block that will be imported on request
|
|
pendingState *state.StateDB // Currently pending state that will be the active on on request
|
|
}
|
|
|
|
// NewSimulatedBackend creates a new binding backend using a simulated blockchain
|
|
// for testing purposes.
|
|
func NewSimulatedBackend(accounts ...core.GenesisAccount) *SimulatedBackend {
|
|
database, _ := ethdb.NewMemDatabase()
|
|
core.WriteGenesisBlockForTesting(database, accounts...)
|
|
blockchain, _ := core.NewBlockChain(database, chainConfig, new(core.FakePow), new(event.TypeMux))
|
|
|
|
backend := &SimulatedBackend{
|
|
database: database,
|
|
blockchain: blockchain,
|
|
}
|
|
backend.Rollback()
|
|
|
|
return backend
|
|
}
|
|
|
|
// Commit imports all the pending transactions as a single block and starts a
|
|
// fresh new state.
|
|
func (b *SimulatedBackend) Commit() {
|
|
if _, err := b.blockchain.InsertChain([]*types.Block{b.pendingBlock}); err != nil {
|
|
panic(err) // This cannot happen unless the simulator is wrong, fail in that case
|
|
}
|
|
b.Rollback()
|
|
}
|
|
|
|
// Rollback aborts all pending transactions, reverting to the last committed state.
|
|
func (b *SimulatedBackend) Rollback() {
|
|
blocks, _ := core.GenerateChain(b.blockchain.CurrentBlock(), b.database, 1, func(int, *core.BlockGen) {})
|
|
|
|
b.pendingBlock = blocks[0]
|
|
b.pendingState, _ = state.New(b.pendingBlock.Root(), b.database)
|
|
}
|
|
|
|
// ContractCall implements ContractCaller.ContractCall, executing the specified
|
|
// contract with the given input data.
|
|
func (b *SimulatedBackend) ContractCall(contract common.Address, data []byte, pending bool) ([]byte, error) {
|
|
// Create a copy of the current state db to screw around with
|
|
var (
|
|
block *types.Block
|
|
statedb *state.StateDB
|
|
)
|
|
if pending {
|
|
block, statedb = b.pendingBlock, b.pendingState.Copy()
|
|
} else {
|
|
block = b.blockchain.CurrentBlock()
|
|
statedb, _ = b.blockchain.State()
|
|
}
|
|
// If there's no code to interact with, respond with an appropriate error
|
|
if code := statedb.GetCode(contract); len(code) == 0 {
|
|
return nil, bind.ErrNoCode
|
|
}
|
|
// Set infinite balance to the a fake caller account
|
|
from := statedb.GetOrNewStateObject(common.Address{})
|
|
from.SetBalance(common.MaxBig)
|
|
|
|
// Assemble the call invocation to measure the gas usage
|
|
msg := callmsg{
|
|
from: from,
|
|
to: &contract,
|
|
gasPrice: new(big.Int),
|
|
gasLimit: common.MaxBig,
|
|
value: new(big.Int),
|
|
data: data,
|
|
}
|
|
// Execute the call and return
|
|
vmenv := core.NewEnv(statedb, chainConfig, b.blockchain, msg, block.Header(), vm.Config{})
|
|
gaspool := new(core.GasPool).AddGas(common.MaxBig)
|
|
|
|
out, _, err := core.ApplyMessage(vmenv, msg, gaspool)
|
|
return out, err
|
|
}
|
|
|
|
// PendingAccountNonce implements ContractTransactor.PendingAccountNonce, retrieving
|
|
// the nonce currently pending for the account.
|
|
func (b *SimulatedBackend) PendingAccountNonce(account common.Address) (uint64, error) {
|
|
return b.pendingState.GetOrNewStateObject(account).Nonce(), nil
|
|
}
|
|
|
|
// SuggestGasPrice implements ContractTransactor.SuggestGasPrice. Since the simulated
|
|
// chain doens't have miners, we just return a gas price of 1 for any call.
|
|
func (b *SimulatedBackend) SuggestGasPrice() (*big.Int, error) {
|
|
return big.NewInt(1), nil
|
|
}
|
|
|
|
// EstimateGasLimit implements ContractTransactor.EstimateGasLimit, executing the
|
|
// requested code against the currently pending block/state and returning the used
|
|
// gas.
|
|
func (b *SimulatedBackend) EstimateGasLimit(sender common.Address, contract *common.Address, value *big.Int, data []byte) (*big.Int, error) {
|
|
// Create a copy of the currently pending state db to screw around with
|
|
var (
|
|
block = b.pendingBlock
|
|
statedb = b.pendingState.Copy()
|
|
)
|
|
// If there's no code to interact with, respond with an appropriate error
|
|
if contract != nil {
|
|
if code := statedb.GetCode(*contract); len(code) == 0 {
|
|
return nil, bind.ErrNoCode
|
|
}
|
|
}
|
|
// Set infinite balance to the a fake caller account
|
|
from := statedb.GetOrNewStateObject(sender)
|
|
from.SetBalance(common.MaxBig)
|
|
|
|
// Assemble the call invocation to measure the gas usage
|
|
msg := callmsg{
|
|
from: from,
|
|
to: contract,
|
|
gasPrice: new(big.Int),
|
|
gasLimit: common.MaxBig,
|
|
value: value,
|
|
data: data,
|
|
}
|
|
// Execute the call and return
|
|
vmenv := core.NewEnv(statedb, chainConfig, b.blockchain, msg, block.Header(), vm.Config{})
|
|
gaspool := new(core.GasPool).AddGas(common.MaxBig)
|
|
|
|
_, gas, _, err := core.NewStateTransition(vmenv, msg, gaspool).TransitionDb()
|
|
return gas, err
|
|
}
|
|
|
|
// SendTransaction implements ContractTransactor.SendTransaction, delegating the raw
|
|
// transaction injection to the remote node.
|
|
func (b *SimulatedBackend) SendTransaction(tx *types.Transaction) error {
|
|
blocks, _ := core.GenerateChain(b.blockchain.CurrentBlock(), b.database, 1, func(number int, block *core.BlockGen) {
|
|
for _, tx := range b.pendingBlock.Transactions() {
|
|
block.AddTx(tx)
|
|
}
|
|
block.AddTx(tx)
|
|
})
|
|
b.pendingBlock = blocks[0]
|
|
b.pendingState, _ = state.New(b.pendingBlock.Root(), b.database)
|
|
|
|
return nil
|
|
}
|
|
|
|
// callmsg implements core.Message to allow passing it as a transaction simulator.
|
|
type callmsg struct {
|
|
from *state.StateObject
|
|
to *common.Address
|
|
gasLimit *big.Int
|
|
gasPrice *big.Int
|
|
value *big.Int
|
|
data []byte
|
|
}
|
|
|
|
func (m callmsg) From() (common.Address, error) { return m.from.Address(), nil }
|
|
func (m callmsg) FromFrontier() (common.Address, error) { return m.from.Address(), nil }
|
|
func (m callmsg) Nonce() uint64 { return m.from.Nonce() }
|
|
func (m callmsg) To() *common.Address { return m.to }
|
|
func (m callmsg) GasPrice() *big.Int { return m.gasPrice }
|
|
func (m callmsg) Gas() *big.Int { return m.gasLimit }
|
|
func (m callmsg) Value() *big.Int { return m.value }
|
|
func (m callmsg) Data() []byte { return m.data }
|