plugeth/accounts/abi/bind/backends/simulated.go
Sina Mahmoodi 2def62b99b
eth/filters: avoid block body retrieval when no matching logs (#25199)
Logs stored on disk have minimal information. Contextual information such as block
number, index of log in block, index of transaction in block are filled in upon request.
We can fill in all these fields only having the block header and list of receipts.
But determining the transaction hash of a log requires the block body.

The goal of this PR is postponing this retrieval until we are sure we the transaction hash.
It happens often that the header bloom filter signals there might be matches in a block,
but after actually checking them reveals the logs do not match. We want to avoid fetching
the body in this case.

Note that this changes the semantics of Backend.GetLogs. Downstream callers of
GetLogs now assume log context fields have not been derived, and need to call
DeriveFields on the logs if necessary.
2023-02-13 10:59:27 +01:00

939 lines
30 KiB
Go

// 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 backends
import (
"context"
"errors"
"fmt"
"math/big"
"sync"
"time"
"github.com/ethereum/go-ethereum"
"github.com/ethereum/go-ethereum/accounts/abi"
"github.com/ethereum/go-ethereum/accounts/abi/bind"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/hexutil"
"github.com/ethereum/go-ethereum/common/math"
"github.com/ethereum/go-ethereum/consensus/ethash"
"github.com/ethereum/go-ethereum/core"
"github.com/ethereum/go-ethereum/core/bloombits"
"github.com/ethereum/go-ethereum/core/rawdb"
"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/eth/filters"
"github.com/ethereum/go-ethereum/ethdb"
"github.com/ethereum/go-ethereum/event"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/params"
"github.com/ethereum/go-ethereum/rpc"
)
// This nil assignment ensures at compile time that SimulatedBackend implements bind.ContractBackend.
var _ bind.ContractBackend = (*SimulatedBackend)(nil)
var (
errBlockNumberUnsupported = errors.New("simulatedBackend cannot access blocks other than the latest block")
errBlockDoesNotExist = errors.New("block does not exist in blockchain")
errTransactionDoesNotExist = errors.New("transaction does not exist")
)
// SimulatedBackend implements bind.ContractBackend, simulating a blockchain in
// the background. Its main purpose is to allow for easy testing of contract bindings.
// Simulated backend implements the following interfaces:
// ChainReader, ChainStateReader, ContractBackend, ContractCaller, ContractFilterer, ContractTransactor,
// DeployBackend, GasEstimator, GasPricer, LogFilterer, PendingContractCaller, TransactionReader, and TransactionSender
type SimulatedBackend struct {
database ethdb.Database // In memory database to store our testing data
blockchain *core.BlockChain // Ethereum blockchain to handle the consensus
mu sync.Mutex
pendingBlock *types.Block // Currently pending block that will be imported on request
pendingState *state.StateDB // Currently pending state that will be the active on request
pendingReceipts types.Receipts // Currently receipts for the pending block
events *filters.EventSystem // for filtering log events live
filterSystem *filters.FilterSystem // for filtering database logs
config *params.ChainConfig
}
// NewSimulatedBackendWithDatabase creates a new binding backend based on the given database
// and uses a simulated blockchain for testing purposes.
// A simulated backend always uses chainID 1337.
func NewSimulatedBackendWithDatabase(database ethdb.Database, alloc core.GenesisAlloc, gasLimit uint64) *SimulatedBackend {
genesis := core.Genesis{
Config: params.AllEthashProtocolChanges,
GasLimit: gasLimit,
Alloc: alloc,
}
blockchain, _ := core.NewBlockChain(database, nil, &genesis, nil, ethash.NewFaker(), vm.Config{}, nil, nil)
backend := &SimulatedBackend{
database: database,
blockchain: blockchain,
config: genesis.Config,
}
filterBackend := &filterBackend{database, blockchain, backend}
backend.filterSystem = filters.NewFilterSystem(filterBackend, filters.Config{})
backend.events = filters.NewEventSystem(backend.filterSystem, false)
backend.rollback(blockchain.CurrentBlock())
return backend
}
// NewSimulatedBackend creates a new binding backend using a simulated blockchain
// for testing purposes.
// A simulated backend always uses chainID 1337.
func NewSimulatedBackend(alloc core.GenesisAlloc, gasLimit uint64) *SimulatedBackend {
return NewSimulatedBackendWithDatabase(rawdb.NewMemoryDatabase(), alloc, gasLimit)
}
// Close terminates the underlying blockchain's update loop.
func (b *SimulatedBackend) Close() error {
b.blockchain.Stop()
return nil
}
// Commit imports all the pending transactions as a single block and starts a
// fresh new state.
func (b *SimulatedBackend) Commit() common.Hash {
b.mu.Lock()
defer b.mu.Unlock()
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
}
blockHash := b.pendingBlock.Hash()
// Using the last inserted block here makes it possible to build on a side
// chain after a fork.
b.rollback(b.pendingBlock)
return blockHash
}
// Rollback aborts all pending transactions, reverting to the last committed state.
func (b *SimulatedBackend) Rollback() {
b.mu.Lock()
defer b.mu.Unlock()
b.rollback(b.blockchain.CurrentBlock())
}
func (b *SimulatedBackend) rollback(parent *types.Block) {
blocks, _ := core.GenerateChain(b.config, parent, ethash.NewFaker(), b.database, 1, func(int, *core.BlockGen) {})
b.pendingBlock = blocks[0]
b.pendingState, _ = state.New(b.pendingBlock.Root(), b.blockchain.StateCache(), nil)
}
// Fork creates a side-chain that can be used to simulate reorgs.
//
// This function should be called with the ancestor block where the new side
// chain should be started. Transactions (old and new) can then be applied on
// top and Commit-ed.
//
// Note, the side-chain will only become canonical (and trigger the events) when
// it becomes longer. Until then CallContract will still operate on the current
// canonical chain.
//
// There is a % chance that the side chain becomes canonical at the same length
// to simulate live network behavior.
func (b *SimulatedBackend) Fork(ctx context.Context, parent common.Hash) error {
b.mu.Lock()
defer b.mu.Unlock()
if len(b.pendingBlock.Transactions()) != 0 {
return errors.New("pending block dirty")
}
block, err := b.blockByHash(ctx, parent)
if err != nil {
return err
}
b.rollback(block)
return nil
}
// stateByBlockNumber retrieves a state by a given blocknumber.
func (b *SimulatedBackend) stateByBlockNumber(ctx context.Context, blockNumber *big.Int) (*state.StateDB, error) {
if blockNumber == nil || blockNumber.Cmp(b.blockchain.CurrentBlock().Number()) == 0 {
return b.blockchain.State()
}
block, err := b.blockByNumber(ctx, blockNumber)
if err != nil {
return nil, err
}
return b.blockchain.StateAt(block.Root())
}
// CodeAt returns the code associated with a certain account in the blockchain.
func (b *SimulatedBackend) CodeAt(ctx context.Context, contract common.Address, blockNumber *big.Int) ([]byte, error) {
b.mu.Lock()
defer b.mu.Unlock()
stateDB, err := b.stateByBlockNumber(ctx, blockNumber)
if err != nil {
return nil, err
}
return stateDB.GetCode(contract), nil
}
// BalanceAt returns the wei balance of a certain account in the blockchain.
func (b *SimulatedBackend) BalanceAt(ctx context.Context, contract common.Address, blockNumber *big.Int) (*big.Int, error) {
b.mu.Lock()
defer b.mu.Unlock()
stateDB, err := b.stateByBlockNumber(ctx, blockNumber)
if err != nil {
return nil, err
}
return stateDB.GetBalance(contract), nil
}
// NonceAt returns the nonce of a certain account in the blockchain.
func (b *SimulatedBackend) NonceAt(ctx context.Context, contract common.Address, blockNumber *big.Int) (uint64, error) {
b.mu.Lock()
defer b.mu.Unlock()
stateDB, err := b.stateByBlockNumber(ctx, blockNumber)
if err != nil {
return 0, err
}
return stateDB.GetNonce(contract), nil
}
// StorageAt returns the value of key in the storage of an account in the blockchain.
func (b *SimulatedBackend) StorageAt(ctx context.Context, contract common.Address, key common.Hash, blockNumber *big.Int) ([]byte, error) {
b.mu.Lock()
defer b.mu.Unlock()
stateDB, err := b.stateByBlockNumber(ctx, blockNumber)
if err != nil {
return nil, err
}
val := stateDB.GetState(contract, key)
return val[:], nil
}
// TransactionReceipt returns the receipt of a transaction.
func (b *SimulatedBackend) TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error) {
b.mu.Lock()
defer b.mu.Unlock()
receipt, _, _, _ := rawdb.ReadReceipt(b.database, txHash, b.config)
if receipt == nil {
return nil, ethereum.NotFound
}
return receipt, nil
}
// TransactionByHash checks the pool of pending transactions in addition to the
// blockchain. The isPending return value indicates whether the transaction has been
// mined yet. Note that the transaction may not be part of the canonical chain even if
// it's not pending.
func (b *SimulatedBackend) TransactionByHash(ctx context.Context, txHash common.Hash) (*types.Transaction, bool, error) {
b.mu.Lock()
defer b.mu.Unlock()
tx := b.pendingBlock.Transaction(txHash)
if tx != nil {
return tx, true, nil
}
tx, _, _, _ = rawdb.ReadTransaction(b.database, txHash)
if tx != nil {
return tx, false, nil
}
return nil, false, ethereum.NotFound
}
// BlockByHash retrieves a block based on the block hash.
func (b *SimulatedBackend) BlockByHash(ctx context.Context, hash common.Hash) (*types.Block, error) {
b.mu.Lock()
defer b.mu.Unlock()
return b.blockByHash(ctx, hash)
}
// blockByHash retrieves a block based on the block hash without Locking.
func (b *SimulatedBackend) blockByHash(ctx context.Context, hash common.Hash) (*types.Block, error) {
if hash == b.pendingBlock.Hash() {
return b.pendingBlock, nil
}
block := b.blockchain.GetBlockByHash(hash)
if block != nil {
return block, nil
}
return nil, errBlockDoesNotExist
}
// BlockByNumber retrieves a block from the database by number, caching it
// (associated with its hash) if found.
func (b *SimulatedBackend) BlockByNumber(ctx context.Context, number *big.Int) (*types.Block, error) {
b.mu.Lock()
defer b.mu.Unlock()
return b.blockByNumber(ctx, number)
}
// blockByNumber retrieves a block from the database by number, caching it
// (associated with its hash) if found without Lock.
func (b *SimulatedBackend) blockByNumber(ctx context.Context, number *big.Int) (*types.Block, error) {
if number == nil || number.Cmp(b.pendingBlock.Number()) == 0 {
return b.blockchain.CurrentBlock(), nil
}
block := b.blockchain.GetBlockByNumber(uint64(number.Int64()))
if block == nil {
return nil, errBlockDoesNotExist
}
return block, nil
}
// HeaderByHash returns a block header from the current canonical chain.
func (b *SimulatedBackend) HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error) {
b.mu.Lock()
defer b.mu.Unlock()
if hash == b.pendingBlock.Hash() {
return b.pendingBlock.Header(), nil
}
header := b.blockchain.GetHeaderByHash(hash)
if header == nil {
return nil, errBlockDoesNotExist
}
return header, nil
}
// HeaderByNumber returns a block header from the current canonical chain. If number is
// nil, the latest known header is returned.
func (b *SimulatedBackend) HeaderByNumber(ctx context.Context, block *big.Int) (*types.Header, error) {
b.mu.Lock()
defer b.mu.Unlock()
if block == nil || block.Cmp(b.pendingBlock.Number()) == 0 {
return b.blockchain.CurrentHeader(), nil
}
return b.blockchain.GetHeaderByNumber(uint64(block.Int64())), nil
}
// TransactionCount returns the number of transactions in a given block.
func (b *SimulatedBackend) TransactionCount(ctx context.Context, blockHash common.Hash) (uint, error) {
b.mu.Lock()
defer b.mu.Unlock()
if blockHash == b.pendingBlock.Hash() {
return uint(b.pendingBlock.Transactions().Len()), nil
}
block := b.blockchain.GetBlockByHash(blockHash)
if block == nil {
return uint(0), errBlockDoesNotExist
}
return uint(block.Transactions().Len()), nil
}
// TransactionInBlock returns the transaction for a specific block at a specific index.
func (b *SimulatedBackend) TransactionInBlock(ctx context.Context, blockHash common.Hash, index uint) (*types.Transaction, error) {
b.mu.Lock()
defer b.mu.Unlock()
if blockHash == b.pendingBlock.Hash() {
transactions := b.pendingBlock.Transactions()
if uint(len(transactions)) < index+1 {
return nil, errTransactionDoesNotExist
}
return transactions[index], nil
}
block := b.blockchain.GetBlockByHash(blockHash)
if block == nil {
return nil, errBlockDoesNotExist
}
transactions := block.Transactions()
if uint(len(transactions)) < index+1 {
return nil, errTransactionDoesNotExist
}
return transactions[index], nil
}
// PendingCodeAt returns the code associated with an account in the pending state.
func (b *SimulatedBackend) PendingCodeAt(ctx context.Context, contract common.Address) ([]byte, error) {
b.mu.Lock()
defer b.mu.Unlock()
return b.pendingState.GetCode(contract), nil
}
func newRevertError(result *core.ExecutionResult) *revertError {
reason, errUnpack := abi.UnpackRevert(result.Revert())
err := errors.New("execution reverted")
if errUnpack == nil {
err = fmt.Errorf("execution reverted: %v", reason)
}
return &revertError{
error: err,
reason: hexutil.Encode(result.Revert()),
}
}
// revertError is an API error that encompasses an EVM revert with JSON error
// code and a binary data blob.
type revertError struct {
error
reason string // revert reason hex encoded
}
// ErrorCode returns the JSON error code for a revert.
// See: https://github.com/ethereum/wiki/wiki/JSON-RPC-Error-Codes-Improvement-Proposal
func (e *revertError) ErrorCode() int {
return 3
}
// ErrorData returns the hex encoded revert reason.
func (e *revertError) ErrorData() interface{} {
return e.reason
}
// CallContract executes a contract call.
func (b *SimulatedBackend) CallContract(ctx context.Context, call ethereum.CallMsg, blockNumber *big.Int) ([]byte, error) {
b.mu.Lock()
defer b.mu.Unlock()
if blockNumber != nil && blockNumber.Cmp(b.blockchain.CurrentBlock().Number()) != 0 {
return nil, errBlockNumberUnsupported
}
stateDB, err := b.blockchain.State()
if err != nil {
return nil, err
}
res, err := b.callContract(ctx, call, b.blockchain.CurrentBlock(), stateDB)
if err != nil {
return nil, err
}
// If the result contains a revert reason, try to unpack and return it.
if len(res.Revert()) > 0 {
return nil, newRevertError(res)
}
return res.Return(), res.Err
}
// PendingCallContract executes a contract call on the pending state.
func (b *SimulatedBackend) PendingCallContract(ctx context.Context, call ethereum.CallMsg) ([]byte, error) {
b.mu.Lock()
defer b.mu.Unlock()
defer b.pendingState.RevertToSnapshot(b.pendingState.Snapshot())
res, err := b.callContract(ctx, call, b.pendingBlock, b.pendingState)
if err != nil {
return nil, err
}
// If the result contains a revert reason, try to unpack and return it.
if len(res.Revert()) > 0 {
return nil, newRevertError(res)
}
return res.Return(), res.Err
}
// PendingNonceAt implements PendingStateReader.PendingNonceAt, retrieving
// the nonce currently pending for the account.
func (b *SimulatedBackend) PendingNonceAt(ctx context.Context, account common.Address) (uint64, error) {
b.mu.Lock()
defer b.mu.Unlock()
return b.pendingState.GetOrNewStateObject(account).Nonce(), nil
}
// SuggestGasPrice implements ContractTransactor.SuggestGasPrice. Since the simulated
// chain doesn't have miners, we just return a gas price of 1 for any call.
func (b *SimulatedBackend) SuggestGasPrice(ctx context.Context) (*big.Int, error) {
b.mu.Lock()
defer b.mu.Unlock()
if b.pendingBlock.Header().BaseFee != nil {
return b.pendingBlock.Header().BaseFee, nil
}
return big.NewInt(1), nil
}
// SuggestGasTipCap implements ContractTransactor.SuggestGasTipCap. Since the simulated
// chain doesn't have miners, we just return a gas tip of 1 for any call.
func (b *SimulatedBackend) SuggestGasTipCap(ctx context.Context) (*big.Int, error) {
return big.NewInt(1), nil
}
// EstimateGas executes the requested code against the currently pending block/state and
// returns the used amount of gas.
func (b *SimulatedBackend) EstimateGas(ctx context.Context, call ethereum.CallMsg) (uint64, error) {
b.mu.Lock()
defer b.mu.Unlock()
// Determine the lowest and highest possible gas limits to binary search in between
var (
lo uint64 = params.TxGas - 1
hi uint64
cap uint64
)
if call.Gas >= params.TxGas {
hi = call.Gas
} else {
hi = b.pendingBlock.GasLimit()
}
// Normalize the max fee per gas the call is willing to spend.
var feeCap *big.Int
if call.GasPrice != nil && (call.GasFeeCap != nil || call.GasTipCap != nil) {
return 0, errors.New("both gasPrice and (maxFeePerGas or maxPriorityFeePerGas) specified")
} else if call.GasPrice != nil {
feeCap = call.GasPrice
} else if call.GasFeeCap != nil {
feeCap = call.GasFeeCap
} else {
feeCap = common.Big0
}
// Recap the highest gas allowance with account's balance.
if feeCap.BitLen() != 0 {
balance := b.pendingState.GetBalance(call.From) // from can't be nil
available := new(big.Int).Set(balance)
if call.Value != nil {
if call.Value.Cmp(available) >= 0 {
return 0, core.ErrInsufficientFundsForTransfer
}
available.Sub(available, call.Value)
}
allowance := new(big.Int).Div(available, feeCap)
if allowance.IsUint64() && hi > allowance.Uint64() {
transfer := call.Value
if transfer == nil {
transfer = new(big.Int)
}
log.Warn("Gas estimation capped by limited funds", "original", hi, "balance", balance,
"sent", transfer, "feecap", feeCap, "fundable", allowance)
hi = allowance.Uint64()
}
}
cap = hi
// Create a helper to check if a gas allowance results in an executable transaction
executable := func(gas uint64) (bool, *core.ExecutionResult, error) {
call.Gas = gas
snapshot := b.pendingState.Snapshot()
res, err := b.callContract(ctx, call, b.pendingBlock, b.pendingState)
b.pendingState.RevertToSnapshot(snapshot)
if err != nil {
if errors.Is(err, core.ErrIntrinsicGas) {
return true, nil, nil // Special case, raise gas limit
}
return true, nil, err // Bail out
}
return res.Failed(), res, nil
}
// Execute the binary search and hone in on an executable gas limit
for lo+1 < hi {
mid := (hi + lo) / 2
failed, _, err := executable(mid)
// If the error is not nil(consensus error), it means the provided message
// call or transaction will never be accepted no matter how much gas it is
// assigned. Return the error directly, don't struggle any more
if err != nil {
return 0, err
}
if failed {
lo = mid
} else {
hi = mid
}
}
// Reject the transaction as invalid if it still fails at the highest allowance
if hi == cap {
failed, result, err := executable(hi)
if err != nil {
return 0, err
}
if failed {
if result != nil && result.Err != vm.ErrOutOfGas {
if len(result.Revert()) > 0 {
return 0, newRevertError(result)
}
return 0, result.Err
}
// Otherwise, the specified gas cap is too low
return 0, fmt.Errorf("gas required exceeds allowance (%d)", cap)
}
}
return hi, nil
}
// callContract implements common code between normal and pending contract calls.
// state is modified during execution, make sure to copy it if necessary.
func (b *SimulatedBackend) callContract(ctx context.Context, call ethereum.CallMsg, block *types.Block, stateDB *state.StateDB) (*core.ExecutionResult, error) {
// Gas prices post 1559 need to be initialized
if call.GasPrice != nil && (call.GasFeeCap != nil || call.GasTipCap != nil) {
return nil, errors.New("both gasPrice and (maxFeePerGas or maxPriorityFeePerGas) specified")
}
head := b.blockchain.CurrentHeader()
if !b.blockchain.Config().IsLondon(head.Number) {
// If there's no basefee, then it must be a non-1559 execution
if call.GasPrice == nil {
call.GasPrice = new(big.Int)
}
call.GasFeeCap, call.GasTipCap = call.GasPrice, call.GasPrice
} else {
// A basefee is provided, necessitating 1559-type execution
if call.GasPrice != nil {
// User specified the legacy gas field, convert to 1559 gas typing
call.GasFeeCap, call.GasTipCap = call.GasPrice, call.GasPrice
} else {
// User specified 1559 gas fields (or none), use those
if call.GasFeeCap == nil {
call.GasFeeCap = new(big.Int)
}
if call.GasTipCap == nil {
call.GasTipCap = new(big.Int)
}
// Backfill the legacy gasPrice for EVM execution, unless we're all zeroes
call.GasPrice = new(big.Int)
if call.GasFeeCap.BitLen() > 0 || call.GasTipCap.BitLen() > 0 {
call.GasPrice = math.BigMin(new(big.Int).Add(call.GasTipCap, head.BaseFee), call.GasFeeCap)
}
}
}
// Ensure message is initialized properly.
if call.Gas == 0 {
call.Gas = 50000000
}
if call.Value == nil {
call.Value = new(big.Int)
}
// Set infinite balance to the fake caller account.
from := stateDB.GetOrNewStateObject(call.From)
from.SetBalance(math.MaxBig256)
// Execute the call.
msg := callMsg{call}
txContext := core.NewEVMTxContext(msg)
evmContext := core.NewEVMBlockContext(block.Header(), b.blockchain, nil)
// Create a new environment which holds all relevant information
// about the transaction and calling mechanisms.
vmEnv := vm.NewEVM(evmContext, txContext, stateDB, b.config, vm.Config{NoBaseFee: true})
gasPool := new(core.GasPool).AddGas(math.MaxUint64)
return core.NewStateTransition(vmEnv, msg, gasPool).TransitionDb()
}
// SendTransaction updates the pending block to include the given transaction.
func (b *SimulatedBackend) SendTransaction(ctx context.Context, tx *types.Transaction) error {
b.mu.Lock()
defer b.mu.Unlock()
// Get the last block
block, err := b.blockByHash(ctx, b.pendingBlock.ParentHash())
if err != nil {
return fmt.Errorf("could not fetch parent")
}
// Check transaction validity
signer := types.MakeSigner(b.blockchain.Config(), block.Number())
sender, err := types.Sender(signer, tx)
if err != nil {
return fmt.Errorf("invalid transaction: %v", err)
}
nonce := b.pendingState.GetNonce(sender)
if tx.Nonce() != nonce {
return fmt.Errorf("invalid transaction nonce: got %d, want %d", tx.Nonce(), nonce)
}
// Include tx in chain
blocks, receipts := core.GenerateChain(b.config, block, ethash.NewFaker(), b.database, 1, func(number int, block *core.BlockGen) {
for _, tx := range b.pendingBlock.Transactions() {
block.AddTxWithChain(b.blockchain, tx)
}
block.AddTxWithChain(b.blockchain, tx)
})
stateDB, _ := b.blockchain.State()
b.pendingBlock = blocks[0]
b.pendingState, _ = state.New(b.pendingBlock.Root(), stateDB.Database(), nil)
b.pendingReceipts = receipts[0]
return nil
}
// FilterLogs executes a log filter operation, blocking during execution and
// returning all the results in one batch.
//
// TODO(karalabe): Deprecate when the subscription one can return past data too.
func (b *SimulatedBackend) FilterLogs(ctx context.Context, query ethereum.FilterQuery) ([]types.Log, error) {
var filter *filters.Filter
if query.BlockHash != nil {
// Block filter requested, construct a single-shot filter
filter = b.filterSystem.NewBlockFilter(*query.BlockHash, query.Addresses, query.Topics)
} else {
// Initialize unset filter boundaries to run from genesis to chain head
from := int64(0)
if query.FromBlock != nil {
from = query.FromBlock.Int64()
}
to := int64(-1)
if query.ToBlock != nil {
to = query.ToBlock.Int64()
}
// Construct the range filter
filter = b.filterSystem.NewRangeFilter(from, to, query.Addresses, query.Topics)
}
// Run the filter and return all the logs
logs, err := filter.Logs(ctx)
if err != nil {
return nil, err
}
res := make([]types.Log, len(logs))
for i, nLog := range logs {
res[i] = *nLog
}
return res, nil
}
// SubscribeFilterLogs creates a background log filtering operation, returning a
// subscription immediately, which can be used to stream the found events.
func (b *SimulatedBackend) SubscribeFilterLogs(ctx context.Context, query ethereum.FilterQuery, ch chan<- types.Log) (ethereum.Subscription, error) {
// Subscribe to contract events
sink := make(chan []*types.Log)
sub, err := b.events.SubscribeLogs(query, sink)
if err != nil {
return nil, err
}
// Since we're getting logs in batches, we need to flatten them into a plain stream
return event.NewSubscription(func(quit <-chan struct{}) error {
defer sub.Unsubscribe()
for {
select {
case logs := <-sink:
for _, nlog := range logs {
select {
case ch <- *nlog:
case err := <-sub.Err():
return err
case <-quit:
return nil
}
}
case err := <-sub.Err():
return err
case <-quit:
return nil
}
}
}), nil
}
// SubscribeNewHead returns an event subscription for a new header.
func (b *SimulatedBackend) SubscribeNewHead(ctx context.Context, ch chan<- *types.Header) (ethereum.Subscription, error) {
// subscribe to a new head
sink := make(chan *types.Header)
sub := b.events.SubscribeNewHeads(sink)
return event.NewSubscription(func(quit <-chan struct{}) error {
defer sub.Unsubscribe()
for {
select {
case head := <-sink:
select {
case ch <- head:
case err := <-sub.Err():
return err
case <-quit:
return nil
}
case err := <-sub.Err():
return err
case <-quit:
return nil
}
}
}), nil
}
// AdjustTime adds a time shift to the simulated clock.
// It can only be called on empty blocks.
func (b *SimulatedBackend) AdjustTime(adjustment time.Duration) error {
b.mu.Lock()
defer b.mu.Unlock()
if len(b.pendingBlock.Transactions()) != 0 {
return errors.New("Could not adjust time on non-empty block")
}
// Get the last block
block := b.blockchain.GetBlockByHash(b.pendingBlock.ParentHash())
if block == nil {
return fmt.Errorf("could not find parent")
}
blocks, _ := core.GenerateChain(b.config, block, ethash.NewFaker(), b.database, 1, func(number int, block *core.BlockGen) {
block.OffsetTime(int64(adjustment.Seconds()))
})
stateDB, _ := b.blockchain.State()
b.pendingBlock = blocks[0]
b.pendingState, _ = state.New(b.pendingBlock.Root(), stateDB.Database(), nil)
return nil
}
// Blockchain returns the underlying blockchain.
func (b *SimulatedBackend) Blockchain() *core.BlockChain {
return b.blockchain
}
// callMsg implements core.Message to allow passing it as a transaction simulator.
type callMsg struct {
ethereum.CallMsg
}
func (m callMsg) From() common.Address { return m.CallMsg.From }
func (m callMsg) Nonce() uint64 { return 0 }
func (m callMsg) IsFake() bool { return true }
func (m callMsg) To() *common.Address { return m.CallMsg.To }
func (m callMsg) GasPrice() *big.Int { return m.CallMsg.GasPrice }
func (m callMsg) GasFeeCap() *big.Int { return m.CallMsg.GasFeeCap }
func (m callMsg) GasTipCap() *big.Int { return m.CallMsg.GasTipCap }
func (m callMsg) Gas() uint64 { return m.CallMsg.Gas }
func (m callMsg) Value() *big.Int { return m.CallMsg.Value }
func (m callMsg) Data() []byte { return m.CallMsg.Data }
func (m callMsg) AccessList() types.AccessList { return m.CallMsg.AccessList }
// filterBackend implements filters.Backend to support filtering for logs without
// taking bloom-bits acceleration structures into account.
type filterBackend struct {
db ethdb.Database
bc *core.BlockChain
backend *SimulatedBackend
}
func (fb *filterBackend) ChainDb() ethdb.Database { return fb.db }
func (fb *filterBackend) EventMux() *event.TypeMux { panic("not supported") }
func (fb *filterBackend) HeaderByNumber(ctx context.Context, number rpc.BlockNumber) (*types.Header, error) {
switch number {
case rpc.PendingBlockNumber:
if block := fb.backend.pendingBlock; block != nil {
return block.Header(), nil
}
return nil, nil
case rpc.LatestBlockNumber:
return fb.bc.CurrentHeader(), nil
case rpc.FinalizedBlockNumber:
if block := fb.bc.CurrentFinalizedBlock(); block != nil {
return block.Header(), nil
}
return nil, errors.New("finalized block not found")
case rpc.SafeBlockNumber:
if block := fb.bc.CurrentSafeBlock(); block != nil {
return block.Header(), nil
}
return nil, errors.New("safe block not found")
default:
return fb.bc.GetHeaderByNumber(uint64(number.Int64())), nil
}
}
func (fb *filterBackend) HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error) {
return fb.bc.GetHeaderByHash(hash), nil
}
func (fb *filterBackend) GetBody(ctx context.Context, hash common.Hash, number rpc.BlockNumber) (*types.Body, error) {
if body := fb.bc.GetBody(hash); body != nil {
return body, nil
}
return nil, errors.New("block body not found")
}
func (fb *filterBackend) PendingBlockAndReceipts() (*types.Block, types.Receipts) {
return fb.backend.pendingBlock, fb.backend.pendingReceipts
}
func (fb *filterBackend) GetReceipts(ctx context.Context, hash common.Hash) (types.Receipts, error) {
number := rawdb.ReadHeaderNumber(fb.db, hash)
if number == nil {
return nil, nil
}
return rawdb.ReadReceipts(fb.db, hash, *number, fb.bc.Config()), nil
}
func (fb *filterBackend) GetLogs(ctx context.Context, hash common.Hash, number uint64) ([][]*types.Log, error) {
logs := rawdb.ReadLogs(fb.db, hash, number, fb.bc.Config())
return logs, nil
}
func (fb *filterBackend) SubscribeNewTxsEvent(ch chan<- core.NewTxsEvent) event.Subscription {
return nullSubscription()
}
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) SubscribePendingLogsEvent(ch chan<- []*types.Log) event.Subscription {
return nullSubscription()
}
func (fb *filterBackend) BloomStatus() (uint64, uint64) { return 4096, 0 }
func (fb *filterBackend) ServiceFilter(ctx context.Context, ms *bloombits.MatcherSession) {
panic("not supported")
}
func (fb *filterBackend) ChainConfig() *params.ChainConfig {
panic("not supported")
}
func (fb *filterBackend) CurrentHeader() *types.Header {
panic("not supported")
}
func nullSubscription() event.Subscription {
return event.NewSubscription(func(quit <-chan struct{}) error {
<-quit
return nil
})
}