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505 lines
17 KiB
505 lines
17 KiB
// Copyright 2015 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 backends
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import (
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"context"
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"errors"
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"fmt"
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"math/big"
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"sync"
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"time"
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ethereum "github.com/ethereum/go-ethereum"
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"github.com/ethereum/go-ethereum/accounts/abi/bind"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/common/math"
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"github.com/ethereum/go-ethereum/consensus/ethash"
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"github.com/ethereum/go-ethereum/core"
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"github.com/ethereum/go-ethereum/core/bloombits"
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"github.com/ethereum/go-ethereum/core/rawdb"
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"github.com/ethereum/go-ethereum/core/state"
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"github.com/ethereum/go-ethereum/core/types"
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"github.com/ethereum/go-ethereum/core/vm"
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"github.com/ethereum/go-ethereum/eth/filters"
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"github.com/ethereum/go-ethereum/ethdb"
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"github.com/ethereum/go-ethereum/event"
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"github.com/ethereum/go-ethereum/params"
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"github.com/ethereum/go-ethereum/rpc"
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)
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// This nil assignment ensures compile time that SimulatedBackend implements bind.ContractBackend.
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var _ bind.ContractBackend = (*SimulatedBackend)(nil)
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var errBlockNumberUnsupported = errors.New("SimulatedBackend cannot access blocks other than the latest block")
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var errGasEstimationFailed = errors.New("gas required exceeds allowance or always failing transaction")
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// SimulatedBackend implements bind.ContractBackend, simulating a blockchain in
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// the background. Its main purpose is to allow easily testing contract bindings.
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type SimulatedBackend struct {
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database ethdb.Database // In memory database to store our testing data
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blockchain *core.BlockChain // Ethereum blockchain to handle the consensus
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mu sync.Mutex
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pendingBlock *types.Block // Currently pending block that will be imported on request
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pendingState *state.StateDB // Currently pending state that will be the active on on request
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events *filters.EventSystem // Event system for filtering log events live
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config *params.ChainConfig
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}
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// NewSimulatedBackend creates a new binding backend using a simulated blockchain
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// for testing purposes.
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func NewSimulatedBackend(alloc core.GenesisAlloc, gasLimit uint64) *SimulatedBackend {
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database := ethdb.NewMemDatabase()
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genesis := core.Genesis{Config: params.AllEthashProtocolChanges, GasLimit: gasLimit, Alloc: alloc}
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genesis.MustCommit(database)
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blockchain, _ := core.NewBlockChain(database, nil, genesis.Config, ethash.NewFaker(), vm.Config{}, nil)
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backend := &SimulatedBackend{
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database: database,
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blockchain: blockchain,
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config: genesis.Config,
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events: filters.NewEventSystem(new(event.TypeMux), &filterBackend{database, blockchain}, false),
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}
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backend.rollback()
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return backend
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}
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// Commit imports all the pending transactions as a single block and starts a
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// fresh new state.
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func (b *SimulatedBackend) Commit() {
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b.mu.Lock()
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defer b.mu.Unlock()
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if _, err := b.blockchain.InsertChain([]*types.Block{b.pendingBlock}); err != nil {
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panic(err) // This cannot happen unless the simulator is wrong, fail in that case
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}
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b.rollback()
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}
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// Rollback aborts all pending transactions, reverting to the last committed state.
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func (b *SimulatedBackend) Rollback() {
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b.mu.Lock()
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defer b.mu.Unlock()
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b.rollback()
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}
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func (b *SimulatedBackend) rollback() {
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blocks, _ := core.GenerateChain(b.config, b.blockchain.CurrentBlock(), ethash.NewFaker(), b.database, 1, func(int, *core.BlockGen) {})
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statedb, _ := b.blockchain.State()
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b.pendingBlock = blocks[0]
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b.pendingState, _ = state.New(b.pendingBlock.Root(), statedb.Database())
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}
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// CodeAt returns the code associated with a certain account in the blockchain.
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func (b *SimulatedBackend) CodeAt(ctx context.Context, contract common.Address, blockNumber *big.Int) ([]byte, error) {
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b.mu.Lock()
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defer b.mu.Unlock()
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if blockNumber != nil && blockNumber.Cmp(b.blockchain.CurrentBlock().Number()) != 0 {
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return nil, errBlockNumberUnsupported
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}
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statedb, _ := b.blockchain.State()
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return statedb.GetCode(contract), nil
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}
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// BalanceAt returns the wei balance of a certain account in the blockchain.
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func (b *SimulatedBackend) BalanceAt(ctx context.Context, contract common.Address, blockNumber *big.Int) (*big.Int, error) {
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b.mu.Lock()
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defer b.mu.Unlock()
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if blockNumber != nil && blockNumber.Cmp(b.blockchain.CurrentBlock().Number()) != 0 {
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return nil, errBlockNumberUnsupported
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}
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statedb, _ := b.blockchain.State()
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return statedb.GetBalance(contract), nil
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}
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// NonceAt returns the nonce of a certain account in the blockchain.
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func (b *SimulatedBackend) NonceAt(ctx context.Context, contract common.Address, blockNumber *big.Int) (uint64, error) {
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b.mu.Lock()
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defer b.mu.Unlock()
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if blockNumber != nil && blockNumber.Cmp(b.blockchain.CurrentBlock().Number()) != 0 {
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return 0, errBlockNumberUnsupported
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}
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statedb, _ := b.blockchain.State()
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return statedb.GetNonce(contract), nil
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}
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// StorageAt returns the value of key in the storage of an account in the blockchain.
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func (b *SimulatedBackend) StorageAt(ctx context.Context, contract common.Address, key common.Hash, blockNumber *big.Int) ([]byte, error) {
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b.mu.Lock()
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defer b.mu.Unlock()
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if blockNumber != nil && blockNumber.Cmp(b.blockchain.CurrentBlock().Number()) != 0 {
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return nil, errBlockNumberUnsupported
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}
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statedb, _ := b.blockchain.State()
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val := statedb.GetState(contract, key)
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return val[:], nil
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}
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// TransactionReceipt returns the receipt of a transaction.
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func (b *SimulatedBackend) TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error) {
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receipt, _, _, _ := rawdb.ReadReceipt(b.database, txHash)
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return receipt, nil
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}
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// TransactionByHash checks the pool of pending transactions in addition to the
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// blockchain. The isPending return value indicates whether the transaction has been
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// mined yet. Note that the transaction may not be part of the canonical chain even if
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// it's not pending.
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func (b *SimulatedBackend) TransactionByHash(ctx context.Context, txHash common.Hash) (*types.Transaction, bool, error) {
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b.mu.Lock()
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defer b.mu.Unlock()
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tx := b.pendingBlock.Transaction(txHash)
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if tx != nil {
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return tx, true, nil
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}
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tx, _, _, _ = rawdb.ReadTransaction(b.database, txHash)
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if tx != nil {
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return tx, false, nil
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}
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return nil, false, ethereum.NotFound
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}
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// PendingCodeAt returns the code associated with an account in the pending state.
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func (b *SimulatedBackend) PendingCodeAt(ctx context.Context, contract common.Address) ([]byte, error) {
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b.mu.Lock()
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defer b.mu.Unlock()
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return b.pendingState.GetCode(contract), nil
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}
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// CallContract executes a contract call.
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func (b *SimulatedBackend) CallContract(ctx context.Context, call ethereum.CallMsg, blockNumber *big.Int) ([]byte, error) {
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b.mu.Lock()
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defer b.mu.Unlock()
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if blockNumber != nil && blockNumber.Cmp(b.blockchain.CurrentBlock().Number()) != 0 {
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return nil, errBlockNumberUnsupported
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}
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state, err := b.blockchain.State()
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if err != nil {
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return nil, err
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}
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rval, _, _, err := b.callContract(ctx, call, b.blockchain.CurrentBlock(), state)
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return rval, err
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}
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// PendingCallContract executes a contract call on the pending state.
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func (b *SimulatedBackend) PendingCallContract(ctx context.Context, call ethereum.CallMsg) ([]byte, error) {
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b.mu.Lock()
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defer b.mu.Unlock()
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defer b.pendingState.RevertToSnapshot(b.pendingState.Snapshot())
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rval, _, _, err := b.callContract(ctx, call, b.pendingBlock, b.pendingState)
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return rval, err
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}
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// PendingNonceAt implements PendingStateReader.PendingNonceAt, retrieving
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// the nonce currently pending for the account.
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func (b *SimulatedBackend) PendingNonceAt(ctx context.Context, account common.Address) (uint64, error) {
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b.mu.Lock()
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defer b.mu.Unlock()
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return b.pendingState.GetOrNewStateObject(account).Nonce(), nil
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}
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// SuggestGasPrice implements ContractTransactor.SuggestGasPrice. Since the simulated
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// chain doesn't have miners, we just return a gas price of 1 for any call.
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func (b *SimulatedBackend) SuggestGasPrice(ctx context.Context) (*big.Int, error) {
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return big.NewInt(1), nil
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}
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// EstimateGas executes the requested code against the currently pending block/state and
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// returns the used amount of gas.
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func (b *SimulatedBackend) EstimateGas(ctx context.Context, call ethereum.CallMsg) (uint64, error) {
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b.mu.Lock()
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defer b.mu.Unlock()
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// Determine the lowest and highest possible gas limits to binary search in between
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var (
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lo = params.TxGas - 1
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hi uint64
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cap uint64
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)
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if call.Gas >= params.TxGas {
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hi = call.Gas
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} else {
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hi = b.pendingBlock.GasLimit()
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}
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cap = hi
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// Create a helper to check if a gas allowance results in an executable transaction
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executable := func(gas uint64) bool {
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call.Gas = gas
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snapshot := b.pendingState.Snapshot()
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_, _, failed, err := b.callContract(ctx, call, b.pendingBlock, b.pendingState)
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b.pendingState.RevertToSnapshot(snapshot)
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if err != nil || failed {
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return false
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}
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return true
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}
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// Execute the binary search and hone in on an executable gas limit
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for lo+1 < hi {
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mid := (hi + lo) / 2
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if !executable(mid) {
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lo = mid
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} else {
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hi = mid
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}
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}
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// Reject the transaction as invalid if it still fails at the highest allowance
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if hi == cap {
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if !executable(hi) {
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return 0, errGasEstimationFailed
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}
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}
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return hi, nil
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}
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// callContract implements common code between normal and pending contract calls.
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// state is modified during execution, make sure to copy it if necessary.
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func (b *SimulatedBackend) callContract(ctx context.Context, call ethereum.CallMsg, block *types.Block, statedb *state.StateDB) ([]byte, uint64, bool, error) {
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// Ensure message is initialized properly.
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if call.GasPrice == nil {
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call.GasPrice = big.NewInt(1)
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}
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if call.Gas == 0 {
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call.Gas = 50000000
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}
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if call.Value == nil {
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call.Value = new(big.Int)
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}
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// Set infinite balance to the fake caller account.
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from := statedb.GetOrNewStateObject(call.From)
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from.SetBalance(math.MaxBig256)
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// Execute the call.
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msg := callmsg{call}
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evmContext := core.NewEVMContext(msg, block.Header(), b.blockchain, nil)
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// Create a new environment which holds all relevant information
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// about the transaction and calling mechanisms.
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vmenv := vm.NewEVM(evmContext, statedb, b.config, vm.Config{})
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gaspool := new(core.GasPool).AddGas(math.MaxUint64)
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return core.NewStateTransition(vmenv, msg, gaspool).TransitionDb()
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}
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// SendTransaction updates the pending block to include the given transaction.
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// It panics if the transaction is invalid.
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func (b *SimulatedBackend) SendTransaction(ctx context.Context, tx *types.Transaction) error {
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b.mu.Lock()
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defer b.mu.Unlock()
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sender, err := types.Sender(types.HomesteadSigner{}, tx)
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if err != nil {
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panic(fmt.Errorf("invalid transaction: %v", err))
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}
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nonce := b.pendingState.GetNonce(sender)
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if tx.Nonce() != nonce {
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panic(fmt.Errorf("invalid transaction nonce: got %d, want %d", tx.Nonce(), nonce))
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}
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blocks, _ := core.GenerateChain(b.config, b.blockchain.CurrentBlock(), ethash.NewFaker(), b.database, 1, func(number int, block *core.BlockGen) {
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for _, tx := range b.pendingBlock.Transactions() {
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block.AddTxWithChain(b.blockchain, tx)
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}
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block.AddTxWithChain(b.blockchain, tx)
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})
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statedb, _ := b.blockchain.State()
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b.pendingBlock = blocks[0]
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b.pendingState, _ = state.New(b.pendingBlock.Root(), statedb.Database())
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return nil
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}
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// FilterLogs executes a log filter operation, blocking during execution and
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// returning all the results in one batch.
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//
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// TODO(karalabe): Deprecate when the subscription one can return past data too.
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func (b *SimulatedBackend) FilterLogs(ctx context.Context, query ethereum.FilterQuery) ([]types.Log, error) {
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var filter *filters.Filter
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if query.BlockHash != nil {
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// Block filter requested, construct a single-shot filter
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filter = filters.NewBlockFilter(&filterBackend{b.database, b.blockchain}, *query.BlockHash, query.Addresses, query.Topics)
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} else {
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// Initialize unset filter boundaried to run from genesis to chain head
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from := int64(0)
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if query.FromBlock != nil {
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from = query.FromBlock.Int64()
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}
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to := int64(-1)
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if query.ToBlock != nil {
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to = query.ToBlock.Int64()
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}
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// Construct the range filter
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filter = filters.NewRangeFilter(&filterBackend{b.database, b.blockchain}, from, to, query.Addresses, query.Topics)
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}
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// Run the filter and return all the logs
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logs, err := filter.Logs(ctx)
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if err != nil {
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return nil, err
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}
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res := make([]types.Log, len(logs))
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for i, log := range logs {
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res[i] = *log
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}
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return res, nil
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}
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// SubscribeFilterLogs creates a background log filtering operation, returning a
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// subscription immediately, which can be used to stream the found events.
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func (b *SimulatedBackend) SubscribeFilterLogs(ctx context.Context, query ethereum.FilterQuery, ch chan<- types.Log) (ethereum.Subscription, error) {
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// Subscribe to contract events
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sink := make(chan []*types.Log)
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sub, err := b.events.SubscribeLogs(query, sink)
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if err != nil {
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return nil, err
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}
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// Since we're getting logs in batches, we need to flatten them into a plain stream
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return event.NewSubscription(func(quit <-chan struct{}) error {
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defer sub.Unsubscribe()
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for {
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select {
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case logs := <-sink:
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for _, log := range logs {
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select {
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case ch <- *log:
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case err := <-sub.Err():
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return err
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case <-quit:
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return nil
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}
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}
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case err := <-sub.Err():
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return err
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case <-quit:
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return nil
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}
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}
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}), nil
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}
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// AdjustTime adds a time shift to the simulated clock.
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func (b *SimulatedBackend) AdjustTime(adjustment time.Duration) error {
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b.mu.Lock()
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defer b.mu.Unlock()
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blocks, _ := core.GenerateChain(b.config, b.blockchain.CurrentBlock(), ethash.NewFaker(), b.database, 1, func(number int, block *core.BlockGen) {
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for _, tx := range b.pendingBlock.Transactions() {
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block.AddTx(tx)
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}
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block.OffsetTime(int64(adjustment.Seconds()))
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})
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statedb, _ := b.blockchain.State()
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b.pendingBlock = blocks[0]
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b.pendingState, _ = state.New(b.pendingBlock.Root(), statedb.Database())
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return nil
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}
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// callmsg implements core.Message to allow passing it as a transaction simulator.
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type callmsg struct {
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ethereum.CallMsg
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}
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func (m callmsg) From() common.Address { return m.CallMsg.From }
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func (m callmsg) Nonce() uint64 { return 0 }
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func (m callmsg) CheckNonce() bool { return false }
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func (m callmsg) To() *common.Address { return m.CallMsg.To }
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func (m callmsg) GasPrice() *big.Int { return m.CallMsg.GasPrice }
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func (m callmsg) Gas() uint64 { return m.CallMsg.Gas }
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func (m callmsg) Value() *big.Int { return m.CallMsg.Value }
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func (m callmsg) Data() []byte { return m.CallMsg.Data }
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// filterBackend implements filters.Backend to support filtering for logs without
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// taking bloom-bits acceleration structures into account.
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type filterBackend struct {
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db ethdb.Database
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bc *core.BlockChain
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}
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func (fb *filterBackend) ChainDb() ethdb.Database { return fb.db }
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func (fb *filterBackend) EventMux() *event.TypeMux { panic("not supported") }
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func (fb *filterBackend) HeaderByNumber(ctx context.Context, block rpc.BlockNumber) (*types.Header, error) {
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if block == rpc.LatestBlockNumber {
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return fb.bc.CurrentHeader(), nil
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}
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return fb.bc.GetHeaderByNumber(uint64(block.Int64())), nil
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}
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func (fb *filterBackend) HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error) {
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return fb.bc.GetHeaderByHash(hash), nil
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}
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func (fb *filterBackend) GetReceipts(ctx context.Context, hash common.Hash) (types.Receipts, error) {
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number := rawdb.ReadHeaderNumber(fb.db, hash)
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if number == nil {
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return nil, nil
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}
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return rawdb.ReadReceipts(fb.db, hash, *number), nil
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}
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func (fb *filterBackend) GetLogs(ctx context.Context, hash common.Hash) ([][]*types.Log, error) {
|
|
number := rawdb.ReadHeaderNumber(fb.db, hash)
|
|
if number == nil {
|
|
return nil, nil
|
|
}
|
|
receipts := rawdb.ReadReceipts(fb.db, hash, *number)
|
|
if receipts == nil {
|
|
return nil, nil
|
|
}
|
|
logs := make([][]*types.Log, len(receipts))
|
|
for i, receipt := range receipts {
|
|
logs[i] = receipt.Logs
|
|
}
|
|
return logs, nil
|
|
}
|
|
|
|
func (fb *filterBackend) SubscribeNewTxsEvent(ch chan<- core.NewTxsEvent) event.Subscription {
|
|
return event.NewSubscription(func(quit <-chan struct{}) error {
|
|
<-quit
|
|
return nil
|
|
})
|
|
}
|
|
func (fb *filterBackend) SubscribeChainEvent(ch chan<- core.ChainEvent) event.Subscription {
|
|
return fb.bc.SubscribeChainEvent(ch)
|
|
}
|
|
func (fb *filterBackend) SubscribeRemovedLogsEvent(ch chan<- core.RemovedLogsEvent) event.Subscription {
|
|
return fb.bc.SubscribeRemovedLogsEvent(ch)
|
|
}
|
|
func (fb *filterBackend) SubscribeLogsEvent(ch chan<- []*types.Log) event.Subscription {
|
|
return fb.bc.SubscribeLogsEvent(ch)
|
|
}
|
|
|
|
func (fb *filterBackend) BloomStatus() (uint64, uint64) { return 4096, 0 }
|
|
func (fb *filterBackend) ServiceFilter(ctx context.Context, ms *bloombits.MatcherSession) {
|
|
panic("not supported")
|
|
}
|
|
|