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// Copyright 2014 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 vm
import (
"math/big"
"github.com/ethereum/go-ethereum/common"
)
// Environment is is required by the virtual machine to get information from
// it's own isolated environment.
// Environment is an EVM requirement and helper which allows access to outside
// information such as states.
type Environment interface {
// The state database
Db() Database
// Creates a restorable snapshot
MakeSnapshot() Database
// Set database to previous snapshot
SetSnapshot(Database)
// Address of the original invoker (first occurance of the VM invoker)
Origin() common.Address
// The block number this VM is invoken on
BlockNumber() *big.Int
// The n'th hash ago from this block number
GetHash(n uint64) common.Hash
// The handler's address
Coinbase() common.Address
// The current time (block time)
Time() *big.Int
// Difficulty set on the current block
Difficulty() *big.Int
// The gas limit of the block
GasLimit() *big.Int
// Determines whether it's possible to transact
CanTransfer(from common.Address, balance *big.Int) bool
// Transfers amount from one account to the other
Transfer(from, to Account, amount *big.Int)
// Adds a LOG to the state
AddLog(*Log)
// Adds a structured log to the env
AddStructLog(StructLog)
// Returns all coalesced structured logs
StructLogs() []StructLog
// Type of the VM
VmType() Type
// Current calling depth
Depth() int
SetDepth(i int)
// Call another contract
Call(me ContractRef, addr common.Address, data []byte, gas, price, value *big.Int) ([]byte, error)
// Take another's contract code and execute within our own context
CallCode(me ContractRef, addr common.Address, data []byte, gas, price, value *big.Int) ([]byte, error)
// Create a new contract
Create(me ContractRef, data []byte, gas, price, value *big.Int) ([]byte, common.Address, error)
}
// Database is a EVM database for full state querying
type Database interface {
GetAccount(common.Address) Account
CreateAccount(common.Address) Account
AddBalance(common.Address, *big.Int)
GetBalance(common.Address) *big.Int
GetNonce(common.Address) uint64
SetNonce(common.Address, uint64)
GetCode(common.Address) []byte
SetCode(common.Address, []byte)
AddRefund(*big.Int)
GetRefund() *big.Int
GetState(common.Address, common.Hash) common.Hash
SetState(common.Address, common.Hash, common.Hash)
Delete(common.Address) bool
Exist(common.Address) bool
IsDeleted(common.Address) bool
}
// StructLog is emited to the Environment each cycle and lists information about the curent internal state
// prior to the execution of the statement.
type StructLog struct {
Pc uint64
Op OpCode
Gas *big.Int
GasCost *big.Int
Memory []byte
Stack []*big.Int
Storage map[common.Hash][]byte
Err error
}
type Account interface {
SubBalance(amount *big.Int)
AddBalance(amount *big.Int)
SetBalance(*big.Int)
SetNonce(uint64)
Balance() *big.Int
Address() common.Address
ReturnGas(*big.Int, *big.Int)
SetCode([]byte)
}
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