// 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.
// 这种nil赋值确保SimulatedBackend在编译时实现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
// SimulatedBackend实现了bind.ContractBackend,在后台模拟区块链。它的主要目的是允许轻松测试合同绑定。
// 模拟后端实现以下接口:ChainReader、ChainStateReader、ContractBackend、ContractCaller、ContractFilterer、ContractTransactor、DeployBackend、GasEstimator、GasPricer、LogFilterer、PendingContractCaller,TransactionReader和TransactionSender
type SimulatedBackend struct {
database ethdb.Database // In memory database to store our testing data 内存数据库,用于存储我们的测试数据
blockchain *core.BlockChain // Ethereum blockchain to handle the consensus 以太坊区块链处理共识
mu sync.Mutex
pendingBlock *types.Block // Currently pending block that will be imported on request 将根据请求导入的当前挂起的块
pendingState *state.StateDB // Currently pending state that will be the active on request 当前挂起状态,将在请求时处于活动状态
pendingReceipts types.Receipts // Currently receipts for the pending block 挂起区块的当前收据
events *filters.EventSystem // for filtering log events live 用于实时筛选日志事件
filterSystem *filters.FilterSystem // for filtering database logs 用于筛选数据库日志
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.
// NewSimulatedBackendWithDatabase基于给定的数据库创建了一个新的绑定后端,并使用模拟区块链进行测试。模拟后端总是使用chainID1337。
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.
// NewSimulatedBackend使用模拟区块链创建了一个新的绑定后端,用于测试目的。模拟后端总是使用chainID1337。
func NewSimulatedBackend(alloc core.GenesisAlloc, gasLimit uint64) *SimulatedBackend {
return NewSimulatedBackendWithDatabase(rawdb.NewMemoryDatabase(), alloc, gasLimit)
}
// Close terminates the underlying blockchain's update loop.
// Close终止底层区块链的更新循环。
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.
// Commit将所有挂起的事务作为单个块导入,并启动一个新的状态。
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.
// 在这里使用最后插入的块可以在叉子之后构建侧链。
b.rollback(b.pendingBlock)
return blockHash
}
// Rollback aborts all pending transactions, reverting to the last committed state.
// 回滚将中止所有挂起的事务,恢复到上次提交的状态。
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.
// Fork创建了一个侧链,可以用来模拟重组。这个函数应该与应该启动新侧链的祖先块一起调用。然后,事务(旧的和新的)可以应用于顶部并提交。
// 注意,只有当侧链变长时,它才会成为规范的(并触发事件)。在此之前,CallContract仍将在当前规范链上运行。
// 侧链在相同长度下成为规范的可能性为%,以模拟实时网络行为。
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.
// stateByBlockNumber按给定的块号检索状态。
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.
// CodeAt返回与区块链中某个帐户关联的代码。
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.
// BalanceAt返回区块链中某个帐户的wei余额。
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.
// NonceAt返回区块链中某个帐户的nonce。
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.
// StorageAt返回区块链中帐户存储中密钥的值。
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.
// TransactionReceipt返回交易的收据。
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.
// TransactionByHash除了检查区块链之外,还检查挂起的交易池。isPending返回值指示事务是否已被挖掘。请注意,即使事务没有挂起,它也可能不是规范链的一部分。
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.
// BlockByHash基于块哈希检索块。
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.
// blockByHash在没有锁定的情况下基于块哈希检索块。
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.
// BlockByNumber按数字从数据库中检索一个块,如果找到,则对其进行缓存(与其哈希相关)。
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.
// blockByNumber按数字从数据库中检索块,如果在没有Lock的情况下找到该块,则对其进行缓存(与其哈希相关)。
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.
// HeaderByHash返回当前规范链中的块标头。
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.
// HeaderByNumber返回当前规范链中的块标头。如果数字为零,则返回最新的已知标头。
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.
// TransactionCount返回给定块中的事务数。
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.
// TransactionInBlock返回特定索引处的特定块的事务。
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.
// PendingCodeAt返回与处于挂起状态的帐户关联的代码。
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.
// revertError是一个API错误,包含带有JSON错误代码和二进制数据blob的EVM还原。
type revertError struct {
error
reason string // revert reason hex encoded
}
// ErrorCode returns the JSON error code for a revert. ErrorCode返回用于恢复的JSON错误代码。
// 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.
// ErrorData返回十六进制编码的还原原因。
func (e *revertError) ErrorData() interface{} {
return e.reason
}
// CallContract executes a contract call.
// CallContract执行合约调用。
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.
// 如果结果包含还原原因,请尝试解压缩并返回它。
if len(res.Revert()) > 0 {
return nil, newRevertError(res)
}
return res.Return(), res.Err
}
// PendingCallContract executes a contract call on the pending state.
// PendingCallContract对挂起状态执行约定调用。
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.
// 如果结果包含还原原因,请尝试解压缩并返回它。
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.
// PendingNonceAt实现PendingStateReader.PendingNonceAt,检索帐户当前挂起的nonce。
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.
// SuggestGasPrice实现ContractTransactor.SuggestGasPrice。由于模拟链没有矿工,我们只为任何呼叫返回1的天然气价格。
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.
// SuggestGasTipCap实现ContractTransactor.SuggestGasTipCap.由于模拟链没有矿工,我们只为任何调用返回1的气体提示。
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.
// EstimateGas针对当前挂起的块/状态执行请求的代码,并返回已使用的气体量。
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
// 确定二元搜索的最低和最高气体极限
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.
// 规范电话愿意花费的每加仑汽油的最高费用。
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.
// 用账户余额重新计算最高天然气备抵。
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
// 创建一个助手以检查气体津贴是否导致可执行事务
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
// 执行二进制搜索并深入了解可执行的气体限制
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
// 如果错误不是零(一致性错误),则意味着无论分配了多少气体,所提供的消息调用或事务都将永远不会被接受。直接返回错误,不要再挣扎了
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
// 如果交易仍以最高限额失败,则拒绝该交易,视其为无效
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
// 否则,指定的气体上限过低
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.
// callContract实现了普通合约调用和挂起合约调用之间的通用代码。状态在执行过程中被修改,请确保在必要时复制它。
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
// 1559年后的天然气价格需要初始化
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
// 如果没有基本费用,那么它必须是非1559执行
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
// 提供基本费用,需要1559类型的执行
if call.GasPrice != nil {
// User specified the legacy gas field, convert to 1559 gas typing
// 用户指定的遗留气田,转换为1559气体类型
call.GasFeeCap, call.GasTipCap = call.GasPrice, call.GasPrice
} else {
// User specified 1559 gas fields (or none), use those
// 用户指定的1559个气田(或无),使用这些气田
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
// 回填EVM执行的遗留气体价格,除非我们都是零
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.
// 请确保消息已正确初始化。
if call.Gas == 0 {
call.Gas = 50000000
}
if call.Value == nil {
call.Value = new(big.Int)
}
// Set infinite balance to the fake caller account.
// 将无限余额设置为伪呼叫者帐户。
from := stateDB.GetOrNewStateObject(call.From)
from.SetBalance(math.MaxBig256)
// Execute the call.
// 执行调用。
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.
// 创建一个新的环境,保存有关事务和调用机制的所有相关信息。
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.
// SendTransaction更新挂起的块以包括给定的事务。
func (b *SimulatedBackend) SendTransaction(ctx context.Context, tx *types.Transaction) error {
b.mu.Lock()
defer b.mu.Unlock()
// Get the last block 获取最后一块
block, err := b.blockByHash(ctx, b.pendingBlock.ParentHash())
if err != nil {
return fmt.Errorf("could not fetch parent")
}
// Check transaction validity 检查交易有效性
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 在链中包含tx
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.
// FilterLogs执行日志筛选操作,在执行过程中进行阻塞,并在一个批处理中返回所有结果。
// 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
// 阻止请求的筛选器,构造单次筛选器
filter = b.filterSystem.NewBlockFilter(*query.BlockHash, query.Addresses, query.Topics)
} else {
// Initialize unset filter boundaries to run from genesis to chain head
// 初始化未设置的过滤器边界以从起源运行到链头
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
// 构造范围过滤器
filter = b.filterSystem.NewRangeFilter(from, to, query.Addresses, query.Topics)
}
// Run the filter and return all the logs
// 运行筛选器并返回所有日志
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.
// SubscribeFilterLogs创建一个后台日志过滤操作,立即返回一个订阅,该订阅可用于流式传输找到的事件。
func (b *SimulatedBackend) SubscribeFilterLogs(ctx context.Context, query ethereum.FilterQuery, ch chan<- types.Log) (ethereum.Subscription, error) {
// Subscribe to contract events
// 订阅合同事件
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
// 由于我们是批量获取原木,我们需要将它们压平成一股普通的气流
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.
// SubscribeNewHead返回一个新标头的事件订阅。
func (b *SimulatedBackend) SubscribeNewHead(ctx context.Context, ch chan<- *types.Header) (ethereum.Subscription, error) {
// subscribe to a new head 订阅新的头
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.
// AdjustTime将时间偏移添加到模拟时钟中。它只能在空块上调用。
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 获取最后一块
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.
// 区块链返回底层区块链。
func (b *SimulatedBackend) Blockchain() *core.BlockChain {
return b.blockchain
}
// callMsg implements core.Message to allow passing it as a transaction simulator.
// callMsg实现了core.Message,以允许将其作为事务模拟器进行传递。
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.
// filterBackend实现了过滤器。Backend支持对日志进行过滤,而不考虑bloom位加速结构。
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
})
}
[Ethereum source code go-ethereum reading] accounts/abi/bind/backend/simulated.go
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