github.com/cryptotooltop/go-ethereum@v0.0.0-20231103184714-151d1922f3e5/core/evm.go (about)

     1  // Copyright 2016 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  	"math/big"
    21  
    22  	"github.com/scroll-tech/go-ethereum/common"
    23  	"github.com/scroll-tech/go-ethereum/consensus"
    24  	"github.com/scroll-tech/go-ethereum/core/types"
    25  	"github.com/scroll-tech/go-ethereum/core/vm"
    26  	"github.com/scroll-tech/go-ethereum/params"
    27  )
    28  
    29  // ChainContext supports retrieving headers and consensus parameters from the
    30  // current blockchain to be used during transaction processing.
    31  type ChainContext interface {
    32  	// Engine retrieves the chain's consensus engine.
    33  	Engine() consensus.Engine
    34  
    35  	// GetHeader returns the hash corresponding to their hash.
    36  	GetHeader(common.Hash, uint64) *types.Header
    37  }
    38  
    39  // NewEVMBlockContext creates a new context for use in the EVM.
    40  func NewEVMBlockContext(header *types.Header, chain ChainContext, chainConfig *params.ChainConfig, author *common.Address) vm.BlockContext {
    41  	var (
    42  		beneficiary common.Address
    43  		baseFee     *big.Int
    44  	)
    45  
    46  	// If we don't have an explicit author (i.e. not mining), extract from the header
    47  	if chainConfig.Scroll.FeeVaultEnabled() {
    48  		beneficiary = *chainConfig.Scroll.FeeVaultAddress
    49  	} else if author == nil {
    50  		beneficiary, _ = chain.Engine().Author(header) // Ignore error, we're past header validation
    51  	} else {
    52  		beneficiary = *author
    53  	}
    54  	if header.BaseFee != nil {
    55  		baseFee = new(big.Int).Set(header.BaseFee)
    56  	}
    57  	return vm.BlockContext{
    58  		CanTransfer: CanTransfer,
    59  		Transfer:    Transfer,
    60  		GetHash:     GetHashFn(header, chain),
    61  		Coinbase:    beneficiary,
    62  		BlockNumber: new(big.Int).Set(header.Number),
    63  		Time:        new(big.Int).SetUint64(header.Time),
    64  		Difficulty:  new(big.Int).Set(header.Difficulty),
    65  		BaseFee:     baseFee,
    66  		GasLimit:    header.GasLimit,
    67  	}
    68  }
    69  
    70  // NewEVMTxContext creates a new transaction context for a single transaction.
    71  func NewEVMTxContext(msg Message) vm.TxContext {
    72  	return vm.TxContext{
    73  		Origin:   msg.From(),
    74  		To:       msg.To(),
    75  		GasPrice: new(big.Int).Set(msg.GasPrice()),
    76  	}
    77  }
    78  
    79  // GetHashFn returns a GetHashFunc which retrieves header hashes by number
    80  func GetHashFn(ref *types.Header, chain ChainContext) func(n uint64) common.Hash {
    81  	// Cache will initially contain [refHash.parent],
    82  	// Then fill up with [refHash.p, refHash.pp, refHash.ppp, ...]
    83  	var cache []common.Hash
    84  
    85  	return func(n uint64) common.Hash {
    86  		// If there's no hash cache yet, make one
    87  		if len(cache) == 0 {
    88  			cache = append(cache, ref.ParentHash)
    89  		}
    90  		if idx := ref.Number.Uint64() - n - 1; idx < uint64(len(cache)) {
    91  			return cache[idx]
    92  		}
    93  		// No luck in the cache, but we can start iterating from the last element we already know
    94  		lastKnownHash := cache[len(cache)-1]
    95  		lastKnownNumber := ref.Number.Uint64() - uint64(len(cache))
    96  
    97  		for {
    98  			header := chain.GetHeader(lastKnownHash, lastKnownNumber)
    99  			if header == nil {
   100  				break
   101  			}
   102  			cache = append(cache, header.ParentHash)
   103  			lastKnownHash = header.ParentHash
   104  			lastKnownNumber = header.Number.Uint64() - 1
   105  			if n == lastKnownNumber {
   106  				return lastKnownHash
   107  			}
   108  		}
   109  		return common.Hash{}
   110  	}
   111  }
   112  
   113  // CanTransfer checks whether there are enough funds in the address' account to make a transfer.
   114  // This does not take the necessary gas in to account to make the transfer valid.
   115  func CanTransfer(db vm.StateDB, addr common.Address, amount *big.Int) bool {
   116  	return db.GetBalance(addr).Cmp(amount) >= 0
   117  }
   118  
   119  // Transfer subtracts amount from sender and adds amount to recipient using the given Db
   120  func Transfer(db vm.StateDB, sender, recipient common.Address, amount *big.Int) {
   121  	db.SubBalance(sender, amount)
   122  	db.AddBalance(recipient, amount)
   123  }