github.com/Night-mk/quorum@v21.1.0+incompatible/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  	"context"
    21  	"math/big"
    22  	"reflect"
    23  
    24  	"github.com/ethereum/go-ethereum/common"
    25  	"github.com/ethereum/go-ethereum/consensus"
    26  	"github.com/ethereum/go-ethereum/core/types"
    27  	"github.com/ethereum/go-ethereum/core/vm"
    28  	"github.com/ethereum/go-ethereum/multitenancy"
    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  	multitenancy.ContextAware
    35  	// Engine retrieves the chain's consensus engine.
    36  	Engine() consensus.Engine
    37  
    38  	// GetHeader returns the hash corresponding to their hash.
    39  	GetHeader(common.Hash, uint64) *types.Header
    40  }
    41  
    42  // NewEVMContext creates a new context for use in the EVM.
    43  func NewEVMContext(msg Message, header *types.Header, chain ChainContext, author *common.Address) vm.Context {
    44  	// If we don't have an explicit author (i.e. not mining), extract from the header
    45  	var beneficiary common.Address
    46  	if author == nil {
    47  		beneficiary, _ = chain.Engine().Author(header) // Ignore error, we're past header validation
    48  	} else {
    49  		beneficiary = *author
    50  	}
    51  	supportsMultitenancy := false
    52  	// mainly to overcome lost of test cases which pass ChainContext as nil value
    53  	// nil interface requires this check to make sure we don't get nil pointer reference error
    54  	if chain != nil && !reflect.ValueOf(chain).IsNil() {
    55  		_, supportsMultitenancy = chain.SupportsMultitenancy(nil)
    56  	}
    57  	return vm.Context{
    58  		CanTransfer: CanTransfer,
    59  		Transfer:    Transfer,
    60  		GetHash:     GetHashFn(header, chain),
    61  		Origin:      msg.From(),
    62  		Coinbase:    beneficiary,
    63  		BlockNumber: new(big.Int).Set(header.Number),
    64  		Time:        new(big.Int).SetUint64(header.Time),
    65  		Difficulty:  new(big.Int).Set(header.Difficulty),
    66  		GasLimit:    header.GasLimit,
    67  		GasPrice:    new(big.Int).Set(msg.GasPrice()),
    68  
    69  		SupportsMultitenancy: supportsMultitenancy,
    70  	}
    71  }
    72  
    73  // Quorum
    74  //
    75  // This EVM context is meant for simulation when doing multitenancy check.
    76  // It enriches the given EVM context with multitenancy-specific references
    77  func NewMultitenancyAwareEVMContext(ctx context.Context, evmCtx vm.Context) vm.Context {
    78  	if f, ok := ctx.Value(multitenancy.CtxKeyAuthorizeCreateFunc).(multitenancy.AuthorizeCreateFunc); ok {
    79  		evmCtx.AuthorizeCreateFunc = f
    80  	}
    81  	if f, ok := ctx.Value(multitenancy.CtxKeyAuthorizeMessageCallFunc).(multitenancy.AuthorizeMessageCallFunc); ok {
    82  		evmCtx.AuthorizeMessageCallFunc = f
    83  	}
    84  	return evmCtx
    85  }
    86  
    87  // GetHashFn returns a GetHashFunc which retrieves header hashes by number
    88  func GetHashFn(ref *types.Header, chain ChainContext) func(n uint64) common.Hash {
    89  	var cache map[uint64]common.Hash
    90  
    91  	return func(n uint64) common.Hash {
    92  		// If there's no hash cache yet, make one
    93  		if cache == nil {
    94  			cache = map[uint64]common.Hash{
    95  				ref.Number.Uint64() - 1: ref.ParentHash,
    96  			}
    97  		}
    98  		// Try to fulfill the request from the cache
    99  		if hash, ok := cache[n]; ok {
   100  			return hash
   101  		}
   102  		// Not cached, iterate the blocks and cache the hashes
   103  		for header := chain.GetHeader(ref.ParentHash, ref.Number.Uint64()-1); header != nil; header = chain.GetHeader(header.ParentHash, header.Number.Uint64()-1) {
   104  			cache[header.Number.Uint64()-1] = header.ParentHash
   105  			if n == header.Number.Uint64()-1 {
   106  				return header.ParentHash
   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  }