github.com/codysnider/go-ethereum@v1.10.18-0.20220420071915-14f4ae99222a/core/state_prefetcher.go (about)

     1  // Copyright 2019 The go-ethereum Authors
     2  // This file is part of the go-ethereum library.
     3  //
     4  // The go-ethereum library is free software: you can redistribute it and/or modify
     5  // it under the terms of the GNU Lesser General Public License as published by
     6  // the Free Software Foundation, either version 3 of the License, or
     7  // (at your option) any later version.
     8  //
     9  // The go-ethereum library is distributed in the hope that it will be useful,
    10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
    11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
    12  // GNU Lesser General Public License for more details.
    13  //
    14  // You should have received a copy of the GNU Lesser General Public License
    15  // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
    16  
    17  package core
    18  
    19  import (
    20  	"sync/atomic"
    21  
    22  	"github.com/ethereum/go-ethereum/consensus"
    23  	"github.com/ethereum/go-ethereum/core/state"
    24  	"github.com/ethereum/go-ethereum/core/types"
    25  	"github.com/ethereum/go-ethereum/core/vm"
    26  	"github.com/ethereum/go-ethereum/params"
    27  )
    28  
    29  // statePrefetcher is a basic Prefetcher, which blindly executes a block on top
    30  // of an arbitrary state with the goal of prefetching potentially useful state
    31  // data from disk before the main block processor start executing.
    32  type statePrefetcher struct {
    33  	config *params.ChainConfig // Chain configuration options
    34  	bc     *BlockChain         // Canonical block chain
    35  	engine consensus.Engine    // Consensus engine used for block rewards
    36  }
    37  
    38  // newStatePrefetcher initialises a new statePrefetcher.
    39  func newStatePrefetcher(config *params.ChainConfig, bc *BlockChain, engine consensus.Engine) *statePrefetcher {
    40  	return &statePrefetcher{
    41  		config: config,
    42  		bc:     bc,
    43  		engine: engine,
    44  	}
    45  }
    46  
    47  // Prefetch processes the state changes according to the Ethereum rules by running
    48  // the transaction messages using the statedb, but any changes are discarded. The
    49  // only goal is to pre-cache transaction signatures and state trie nodes.
    50  func (p *statePrefetcher) Prefetch(block *types.Block, statedb *state.StateDB, cfg vm.Config, interrupt *uint32) {
    51  	var (
    52  		header       = block.Header()
    53  		gaspool      = new(GasPool).AddGas(block.GasLimit())
    54  		blockContext = NewEVMBlockContext(header, p.bc, nil)
    55  		evm          = vm.NewEVM(blockContext, vm.TxContext{}, statedb, p.config, cfg)
    56  		signer       = types.MakeSigner(p.config, header.Number)
    57  	)
    58  	// Iterate over and process the individual transactions
    59  	byzantium := p.config.IsByzantium(block.Number())
    60  	for i, tx := range block.Transactions() {
    61  		// If block precaching was interrupted, abort
    62  		if interrupt != nil && atomic.LoadUint32(interrupt) == 1 {
    63  			return
    64  		}
    65  		// Convert the transaction into an executable message and pre-cache its sender
    66  		msg, err := tx.AsMessage(signer, header.BaseFee)
    67  		if err != nil {
    68  			return // Also invalid block, bail out
    69  		}
    70  		statedb.Prepare(tx.Hash(), i)
    71  		if err := precacheTransaction(msg, p.config, gaspool, statedb, header, evm); err != nil {
    72  			return // Ugh, something went horribly wrong, bail out
    73  		}
    74  		// If we're pre-byzantium, pre-load trie nodes for the intermediate root
    75  		if !byzantium {
    76  			statedb.IntermediateRoot(true)
    77  		}
    78  	}
    79  	// If were post-byzantium, pre-load trie nodes for the final root hash
    80  	if byzantium {
    81  		statedb.IntermediateRoot(true)
    82  	}
    83  }
    84  
    85  // precacheTransaction attempts to apply a transaction to the given state database
    86  // and uses the input parameters for its environment. The goal is not to execute
    87  // the transaction successfully, rather to warm up touched data slots.
    88  func precacheTransaction(msg types.Message, config *params.ChainConfig, gaspool *GasPool, statedb *state.StateDB, header *types.Header, evm *vm.EVM) error {
    89  	// Update the evm with the new transaction context.
    90  	evm.Reset(NewEVMTxContext(msg), statedb)
    91  	// Add addresses to access list if applicable
    92  	_, err := ApplyMessage(evm, msg, gaspool)
    93  	return err
    94  }