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

     1  // Copyright 2021 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 les
    18  
    19  import (
    20  	"context"
    21  	"errors"
    22  	"fmt"
    23  
    24  	"github.com/ethereum/go-ethereum/core"
    25  	"github.com/ethereum/go-ethereum/core/state"
    26  	"github.com/ethereum/go-ethereum/core/types"
    27  	"github.com/ethereum/go-ethereum/core/vm"
    28  	"github.com/ethereum/go-ethereum/light"
    29  )
    30  
    31  // stateAtBlock retrieves the state database associated with a certain block.
    32  func (leth *LightEthereum) stateAtBlock(ctx context.Context, block *types.Block, reexec uint64) (*state.StateDB, error) {
    33  	return light.NewState(ctx, block.Header(), leth.odr), nil
    34  }
    35  
    36  // stateAtTransaction returns the execution environment of a certain transaction.
    37  func (leth *LightEthereum) stateAtTransaction(ctx context.Context, block *types.Block, txIndex int, reexec uint64) (core.Message, vm.BlockContext, *state.StateDB, error) {
    38  	// Short circuit if it's genesis block.
    39  	if block.NumberU64() == 0 {
    40  		return nil, vm.BlockContext{}, nil, errors.New("no transaction in genesis")
    41  	}
    42  	// Create the parent state database
    43  	parent, err := leth.blockchain.GetBlock(ctx, block.ParentHash(), block.NumberU64()-1)
    44  	if err != nil {
    45  		return nil, vm.BlockContext{}, nil, err
    46  	}
    47  	statedb, err := leth.stateAtBlock(ctx, parent, reexec)
    48  	if err != nil {
    49  		return nil, vm.BlockContext{}, nil, err
    50  	}
    51  	if txIndex == 0 && len(block.Transactions()) == 0 {
    52  		return nil, vm.BlockContext{}, statedb, nil
    53  	}
    54  	// Recompute transactions up to the target index.
    55  	signer := types.MakeSigner(leth.blockchain.Config(), block.Number())
    56  	for idx, tx := range block.Transactions() {
    57  		// Assemble the transaction call message and return if the requested offset
    58  		msg, _ := tx.AsMessage(signer, block.BaseFee())
    59  		txContext := core.NewEVMTxContext(msg)
    60  		context := core.NewEVMBlockContext(block.Header(), leth.blockchain, nil)
    61  		statedb.Prepare(tx.Hash(), idx)
    62  		if idx == txIndex {
    63  			return msg, context, statedb, nil
    64  		}
    65  		// Not yet the searched for transaction, execute on top of the current state
    66  		vmenv := vm.NewEVM(context, txContext, statedb, leth.blockchain.Config(), vm.Config{})
    67  		if _, err := core.ApplyMessage(vmenv, msg, new(core.GasPool).AddGas(tx.Gas())); err != nil {
    68  			return nil, vm.BlockContext{}, nil, fmt.Errorf("transaction %#x failed: %v", tx.Hash(), err)
    69  		}
    70  		// Ensure any modifications are committed to the state
    71  		// Only delete empty objects if EIP158/161 (a.k.a Spurious Dragon) is in effect
    72  		statedb.Finalise(vmenv.ChainConfig().IsEIP158(block.Number()))
    73  	}
    74  	return nil, vm.BlockContext{}, nil, fmt.Errorf("transaction index %d out of range for block %#x", txIndex, block.Hash())
    75  }