134 lines
3.7 KiB
Go
134 lines
3.7 KiB
Go
// Copyright 2014 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package vm
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import (
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"math/big"
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"github.com/ethereum/go-ethereum/common"
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)
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// ContractRef is a reference to the contract's backing object
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type ContractRef interface {
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ReturnGas(*big.Int, *big.Int)
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Address() common.Address
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SetCode([]byte)
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EachStorage(cb func(key, value []byte))
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}
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// Contract represents an ethereum contract in the state database. It contains
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// the the contract code, calling arguments. Contract implements ContractReg
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type Contract struct {
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caller ContractRef
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self ContractRef
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jumpdests destinations // result of JUMPDEST analysis.
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Code []byte
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Input []byte
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CodeAddr *common.Address
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value, Gas, UsedGas, Price *big.Int
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Args []byte
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}
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// Create a new context for the given data items.
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func NewContract(caller ContractRef, object ContractRef, value, gas, price *big.Int) *Contract {
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c := &Contract{caller: caller, self: object, Args: nil}
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if parent, ok := caller.(*Contract); ok {
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// Reuse JUMPDEST analysis from parent context if available.
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c.jumpdests = parent.jumpdests
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} else {
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c.jumpdests = make(destinations)
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}
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// Gas should be a pointer so it can safely be reduced through the run
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// This pointer will be off the state transition
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c.Gas = gas //new(big.Int).Set(gas)
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c.value = new(big.Int).Set(value)
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// In most cases price and value are pointers to transaction objects
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// and we don't want the transaction's values to change.
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c.Price = new(big.Int).Set(price)
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c.UsedGas = new(big.Int)
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return c
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}
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// GetOp returns the n'th element in the contract's byte array
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func (c *Contract) GetOp(n uint64) OpCode {
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return OpCode(c.GetByte(n))
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}
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// GetByte returns the n'th byte in the contract's byte array
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func (c *Contract) GetByte(n uint64) byte {
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if n < uint64(len(c.Code)) {
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return c.Code[n]
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}
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return 0
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}
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// Return returns the given ret argument and returns any remaining gas to the
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// caller
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func (c *Contract) Return(ret []byte) []byte {
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// Return the remaining gas to the caller
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c.caller.ReturnGas(c.Gas, c.Price)
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return ret
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}
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// UseGas attempts the use gas and subtracts it and returns true on success
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func (c *Contract) UseGas(gas *big.Int) (ok bool) {
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ok = useGas(c.Gas, gas)
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if ok {
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c.UsedGas.Add(c.UsedGas, gas)
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}
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return
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}
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// ReturnGas adds the given gas back to itself.
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func (c *Contract) ReturnGas(gas, price *big.Int) {
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// Return the gas to the context
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c.Gas.Add(c.Gas, gas)
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c.UsedGas.Sub(c.UsedGas, gas)
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}
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// Address returns the contracts address
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func (c *Contract) Address() common.Address {
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return c.self.Address()
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}
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// SetCode sets the code to the contract
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func (self *Contract) SetCode(code []byte) {
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self.Code = code
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}
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// SetCallCode sets the code of the contract and address of the backing data
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// object
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func (self *Contract) SetCallCode(addr *common.Address, code []byte) {
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self.Code = code
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self.CodeAddr = addr
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}
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// EachStorage iterates the contract's storage and calls a method for every key
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// value pair.
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func (self *Contract) EachStorage(cb func(key, value []byte)) {
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self.caller.EachStorage(cb)
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}
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