env.go

// Copyright (C) 2021 The Ontology Authors
// Copyright 2015 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 runtime

import (
	"math/big"

	"github.com/qbyyf/go-ethereum/common"
	"github.com/qbyyf/ontology/vm/evm"
)

func NewEnv(cfg *Config) *evm.EVM {
	txContext := evm.TxContext{
		Origin:   cfg.Origin,
		GasPrice: cfg.GasPrice,
	}
	blockContext := evm.BlockContext{
		CanTransfer: CanTransfer,
		Transfer:    Transfer,
		GetHash:     cfg.GetHashFn,
		Coinbase:    cfg.Coinbase,
		BlockNumber: cfg.BlockNumber,
		Time:        cfg.Time,
		Difficulty:  cfg.Difficulty,
		GasLimit:    cfg.GasLimit,
	}

	return evm.NewEVM(blockContext, txContext, cfg.State, cfg.ChainConfig, cfg.EVMConfig)
}

// 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 evm.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 evm.StateDB, sender, recipient common.Address, amount *big.Int) {
	db.SubBalance(sender, amount)
	db.AddBalance(recipient, amount)
	evm.MakeOngTransferLog(db, sender, recipient, amount)
}