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-rw-r--r--core/vm/contract.go126
1 files changed, 126 insertions, 0 deletions
diff --git a/core/vm/contract.go b/core/vm/contract.go
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+++ b/core/vm/contract.go
@@ -0,0 +1,126 @@
+// 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"
+)
+
+// ContractRef is a reference to the contract's backing object
+type ContractRef interface {
+ ReturnGas(*big.Int, *big.Int)
+ Address() common.Address
+ SetCode([]byte)
+}
+
+// Contract represents an ethereum contract in the state database. It contains
+// the the contract code, calling arguments. Contract implements ContractReg
+type Contract struct {
+ caller ContractRef
+ self ContractRef
+
+ jumpdests destinations // result of JUMPDEST analysis.
+
+ Code []byte
+ Input []byte
+ CodeAddr *common.Address
+
+ value, Gas, UsedGas, Price *big.Int
+
+ Args []byte
+}
+
+// Create a new context for the given data items.
+func NewContract(caller ContractRef, object ContractRef, value, gas, price *big.Int) *Contract {
+ c := &Contract{caller: caller, self: object, Args: nil}
+
+ if parent, ok := caller.(*Contract); ok {
+ // Reuse JUMPDEST analysis from parent context if available.
+ c.jumpdests = parent.jumpdests
+ } else {
+ c.jumpdests = make(destinations)
+ }
+
+ // Gas should be a pointer so it can safely be reduced through the run
+ // This pointer will be off the state transition
+ c.Gas = gas //new(big.Int).Set(gas)
+ c.value = new(big.Int).Set(value)
+ // In most cases price and value are pointers to transaction objects
+ // and we don't want the transaction's values to change.
+ c.Price = new(big.Int).Set(price)
+ c.UsedGas = new(big.Int)
+
+ return c
+}
+
+// GetOp returns the n'th element in the contract's byte array
+func (c *Contract) GetOp(n uint64) OpCode {
+ return OpCode(c.GetByte(n))
+}
+
+// GetByte returns the n'th byte in the contract's byte array
+func (c *Contract) GetByte(n uint64) byte {
+ if n < uint64(len(c.Code)) {
+ return c.Code[n]
+ }
+
+ return 0
+}
+
+// Return returns the given ret argument and returns any remaining gas to the
+// caller
+func (c *Contract) Return(ret []byte) []byte {
+ // Return the remaining gas to the caller
+ c.caller.ReturnGas(c.Gas, c.Price)
+
+ return ret
+}
+
+// UseGas attempts the use gas and subtracts it and returns true on success
+func (c *Contract) UseGas(gas *big.Int) (ok bool) {
+ ok = useGas(c.Gas, gas)
+ if ok {
+ c.UsedGas.Add(c.UsedGas, gas)
+ }
+ return
+}
+
+// ReturnGas adds the given gas back to itself.
+func (c *Contract) ReturnGas(gas, price *big.Int) {
+ // Return the gas to the context
+ c.Gas.Add(c.Gas, gas)
+ c.UsedGas.Sub(c.UsedGas, gas)
+}
+
+// Address returns the contracts address
+func (c *Contract) Address() common.Address {
+ return c.self.Address()
+}
+
+// SetCode sets the code to the contract
+func (self *Contract) SetCode(code []byte) {
+ self.Code = code
+}
+
+// SetCallCode sets the address of the code address and sets the code
+// of the contract according to the backing database.
+func (self *Contract) SetCallCode(addr *common.Address, code []byte) {
+ self.Code = code
+ self.CodeAddr = addr
+}