The core protocol of WoopChain
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woop/core/evm.go

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4.4 KiB

// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package core
import (
"math/big"
types2 "github.com/harmony-one/harmony/staking/types"
"github.com/ethereum/go-ethereum/common"
"github.com/harmony-one/harmony/block"
consensus_engine "github.com/harmony-one/harmony/consensus/engine"
"github.com/harmony-one/harmony/core/types"
"github.com/harmony-one/harmony/core/vm"
"github.com/harmony-one/harmony/internal/utils"
)
// ChainContext supports retrieving headers and consensus parameters from the
// current blockchain to be used during transaction processing.
type ChainContext interface {
// Engine retrieves the chain's consensus engine.
Engine() consensus_engine.Engine
// GetHeader returns the hash corresponding to their hash.
GetHeader(common.Hash, uint64) *block.Header
// ReadDelegationsByDelegator returns the validators list of a delegator
ReadDelegationsByDelegator(common.Address) ([]types2.DelegationIndex, error)
// ReadValidatorSnapshot returns the snapshot of validator at the beginning of current epoch.
ReadValidatorSnapshot(common.Address) (*types2.ValidatorWrapper, error)
// GetECDSAFromCoinbase retrieves corresponding ECDSA address from the coinbase (BLS Address)
GetECDSAFromCoinbase(*block.Header) (common.Address, error)
}
// NewEVMContext creates a new context for use in the EVM.
func NewEVMContext(msg Message, header *block.Header, chain ChainContext, author *common.Address) vm.Context {
// If we don't have an explicit author (i.e. not mining), extract from the header
var beneficiary common.Address
var err error
if author == nil {
beneficiary, err = chain.GetECDSAFromCoinbase(header) // Ignore error, we're past header validation
if err != nil {
utils.Logger().Warn().Msg("oops! We cannot find any beneficiary from header")
}
} else {
beneficiary = *author
}
return vm.Context{
CanTransfer: CanTransfer,
Transfer: Transfer,
GetHash: GetHashFn(header, chain),
Origin: msg.From(),
Coinbase: beneficiary,
BlockNumber: header.Number(),
EpochNumber: header.Epoch(),
Time: header.Time(),
GasLimit: header.GasLimit(),
GasPrice: new(big.Int).Set(msg.GasPrice()),
}
}
// GetHashFn returns a GetHashFunc which retrieves header hashes by number
func GetHashFn(ref *block.Header, chain ChainContext) func(n uint64) common.Hash {
var cache map[uint64]common.Hash
return func(n uint64) common.Hash {
// If there's no hash cache yet, make one
if cache == nil {
cache = map[uint64]common.Hash{
ref.Number().Uint64() - 1: ref.ParentHash(),
}
}
// Try to fulfill the request from the cache
if hash, ok := cache[n]; ok {
return hash
}
// Not cached, iterate the blocks and cache the hashes
for header := chain.GetHeader(ref.ParentHash(), ref.Number().Uint64()-1); header != nil; header = chain.GetHeader(header.ParentHash(), header.Number().Uint64()-1) {
cache[header.Number().Uint64()-1] = header.ParentHash()
if n == header.Number().Uint64()-1 {
return header.ParentHash()
}
}
return common.Hash{}
}
}
// CanTransfer checks whether there are enough funds in the address' account to make a transfer.
// This does not take the necessary gas in to account to make the transfer valid.
func CanTransfer(db vm.StateDB, addr common.Address, amount *big.Int) bool {
return db.GetBalance(addr).Cmp(amount) >= 0
}
// Transfer subtracts amount from sender and adds amount to recipient using the given Db
func Transfer(db vm.StateDB, sender, recipient common.Address, amount *big.Int, txType types.TransactionType) {
if txType == types.SameShardTx || txType == types.SubtractionOnly {
db.SubBalance(sender, amount)
}
if txType == types.SameShardTx {
db.AddBalance(recipient, amount)
}
}