github.com/kisexp/xdchain@v0.0.0-20211206025815-490d6b732aa7/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/kisexp/xdchain/common"
    23  	"github.com/kisexp/xdchain/consensus"
    24  	"github.com/kisexp/xdchain/core/mps"
    25  	"github.com/kisexp/xdchain/core/state"
    26  	"github.com/kisexp/xdchain/core/types"
    27  	"github.com/kisexp/xdchain/core/vm"
    28  	"github.com/kisexp/xdchain/params"
    29  )
    30  
    31  // ChainContext supports retrieving headers and consensus parameters from the
    32  // current blockchain to be used during transaction processing.
    33  type ChainContext interface {
    34  	// Engine retrieves the chain's consensus engine.
    35  	Engine() consensus.Engine
    36  
    37  	// GetHeader returns the hash corresponding to their hash.
    38  	GetHeader(common.Hash, uint64) *types.Header
    39  
    40  	// Config retrieves the chain's fork configuration
    41  	Config() *params.ChainConfig
    42  
    43  	// Quorum
    44  
    45  	// QuorumConfig retrieves the Quorum chain's configuration
    46  	QuorumConfig() *QuorumChainConfig
    47  
    48  	// PrivateStateManager returns the private state manager
    49  	PrivateStateManager() mps.PrivateStateManager
    50  
    51  	// CheckAndSetPrivateState updates the private state as a part contract state extension
    52  	CheckAndSetPrivateState(txLogs []*types.Log, privateState *state.StateDB, psi types.PrivateStateIdentifier)
    53  
    54  	// End Quorum
    55  }
    56  
    57  // NewEVMBlockContext creates a new context for use in the EVM.
    58  func NewEVMBlockContext(header *types.Header, chain ChainContext, author *common.Address) vm.BlockContext {
    59  	// If we don't have an explicit author (i.e. not mining), extract from the header
    60  	var beneficiary common.Address
    61  	if author == nil {
    62  		beneficiary, _ = chain.Engine().Author(header) // Ignore error, we're past header validation
    63  	} else {
    64  		beneficiary = *author
    65  	}
    66  	return vm.BlockContext{
    67  		CanTransfer: CanTransfer,
    68  		Transfer:    Transfer,
    69  		GetHash:     GetHashFn(header, chain),
    70  		Coinbase:    beneficiary,
    71  		BlockNumber: new(big.Int).Set(header.Number),
    72  		Time:        new(big.Int).SetUint64(header.Time),
    73  		Difficulty:  new(big.Int).Set(header.Difficulty),
    74  		GasLimit:    header.GasLimit,
    75  	}
    76  }
    77  
    78  // NewEVMTxContext creates a new transaction context for a single transaction.
    79  func NewEVMTxContext(msg Message) vm.TxContext {
    80  	return vm.TxContext{
    81  		Origin:   msg.From(),
    82  		GasPrice: new(big.Int).Set(msg.GasPrice()),
    83  	}
    84  }
    85  
    86  // GetHashFn returns a GetHashFunc which retrieves header hashes by number
    87  func GetHashFn(ref *types.Header, chain ChainContext) func(n uint64) common.Hash {
    88  	// Cache will initially contain [refHash.parent],
    89  	// Then fill up with [refHash.p, refHash.pp, refHash.ppp, ...]
    90  	var cache []common.Hash
    91  
    92  	return func(n uint64) common.Hash {
    93  		// If there's no hash cache yet, make one
    94  		if len(cache) == 0 {
    95  			cache = append(cache, ref.ParentHash)
    96  		}
    97  		if idx := ref.Number.Uint64() - n - 1; idx < uint64(len(cache)) {
    98  			return cache[idx]
    99  		}
   100  		// No luck in the cache, but we can start iterating from the last element we already know
   101  		lastKnownHash := cache[len(cache)-1]
   102  		lastKnownNumber := ref.Number.Uint64() - uint64(len(cache))
   103  
   104  		for {
   105  			header := chain.GetHeader(lastKnownHash, lastKnownNumber)
   106  			if header == nil {
   107  				break
   108  			}
   109  			cache = append(cache, header.ParentHash)
   110  			lastKnownHash = header.ParentHash
   111  			lastKnownNumber = header.Number.Uint64() - 1
   112  			if n == lastKnownNumber {
   113  				return lastKnownHash
   114  			}
   115  		}
   116  		return common.Hash{}
   117  	}
   118  }
   119  
   120  // CanTransfer checks whether there are enough funds in the address' account to make a transfer.
   121  // This does not take the necessary gas in to account to make the transfer valid.
   122  func CanTransfer(db vm.StateDB, addr common.Address, amount *big.Int) bool {
   123  	return db.GetBalance(addr).Cmp(amount) >= 0
   124  }
   125  
   126  // Transfer subtracts amount from sender and adds amount to recipient using the given Db
   127  func Transfer(db vm.StateDB, sender, recipient common.Address, amount *big.Int) {
   128  	db.SubBalance(sender, amount)
   129  	db.AddBalance(recipient, amount)
   130  }