github.com/n1ghtfa1l/go-vnt@v0.6.4-alpha.6/core/wavm/contract/wasm_contract.go (about) 1 // Copyright 2015 The go-ethereum Authors 2 // This file is part of the go-ethereum library. 3 // 4 // The go-ethereum library is free software: you can redistribute it and/or modify 5 // it under the terms of the GNU Lesser General Public License as published by 6 // the Free Software Foundation, either version 3 of the License, or 7 // (at your option) any later version. 8 // 9 // The go-ethereum library is distributed in the hope that it will be useful, 10 // but WITHOUT ANY WARRANTY; without even the implied warranty of 11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 // GNU Lesser General Public License for more details. 13 // 14 // You should have received a copy of the GNU Lesser General Public License 15 // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>. 16 17 package contract 18 19 import ( 20 "math/big" 21 22 "github.com/vntchain/go-vnt/core/vm/interface" 23 24 "github.com/vntchain/go-vnt/common" 25 ) 26 27 type WasmCode struct { 28 Code []byte 29 Abi []byte 30 Compiled []byte 31 } 32 33 type WASMContractRef interface { 34 Address() common.Address 35 } 36 37 // Contract represents an VNTChain contract in the state database. It contains 38 // the the contract code, calling arguments. Contract implements ContractRef 39 type WASMContract struct { 40 // CallerAddress is the result of the caller which initialised this 41 // contract. However when the "call method" is delegated this value 42 // needs to be initialised to that of the caller's caller. 43 CallerAddress common.Address 44 caller WASMContractRef 45 self WASMContractRef 46 47 Code []byte 48 CodeHash common.Hash 49 CodeAddr *common.Address 50 Input []byte 51 52 GasLimit uint64 53 Gas uint64 54 value *big.Int 55 56 Args []byte 57 58 DelegateCall bool 59 } 60 61 // NewWASMContract returns a new contract environment for the execution of WAVM. 62 func NewWASMContract(caller WASMContractRef, object WASMContractRef, value *big.Int, gas uint64) *WASMContract { 63 c := &WASMContract{CallerAddress: caller.Address(), caller: caller, self: object, Args: nil} 64 65 // Gas should be a pointer so it can safely be reduced through the run 66 // This pointer will be off the state transition 67 c.Gas = gas 68 c.GasLimit = gas 69 // ensures a value is set 70 c.value = value 71 72 return c 73 } 74 75 // AsDelegate sets the contract to be a delegate call and returns the current 76 // contract (for chaining calls) 77 func (c *WASMContract) AsDelegate() inter.Contract { 78 c.DelegateCall = true 79 // NOTE: caller must, at all times be a contract. It should never happen 80 // that caller is something other than a Contract. 81 parent := c.caller.(*WASMContract) 82 c.CallerAddress = parent.CallerAddress 83 c.value = parent.value 84 85 return c 86 } 87 88 // GetByte returns the n'th byte in the contract's byte array 89 func (c *WASMContract) GetByte(n uint64) byte { 90 if n < uint64(len(c.Code)) { 91 return c.Code[n] 92 } 93 94 return 0 95 } 96 97 // Caller returns the caller of the contract. 98 // 99 // Caller will recursively call caller when the contract is a delegate 100 // call, including that of caller's caller. 101 func (c *WASMContract) Caller() common.Address { 102 return c.CallerAddress 103 } 104 105 // UseGas attempts the use gas and subtracts it and returns true on success 106 func (c *WASMContract) UseGas(gas uint64) (ok bool) { 107 if c.Gas < gas { 108 return false 109 } 110 c.Gas -= gas 111 return true 112 } 113 114 // Address returns the contracts address 115 func (c *WASMContract) Address() common.Address { 116 return c.self.Address() 117 } 118 119 // Value returns the contracts value (sent to it from it's caller) 120 func (c *WASMContract) Value() *big.Int { 121 return c.value 122 } 123 124 // SetCode sets the code to the contract 125 func (c *WASMContract) SetCode(hash common.Hash, code []byte) { 126 c.Code = code 127 c.CodeHash = hash 128 } 129 130 // SetCallCode sets the code of the contract and address of the backing data 131 // object 132 func (c *WASMContract) SetCallCode(addr *common.Address, hash common.Hash, code []byte) { 133 c.Code = code 134 c.CodeHash = hash 135 c.CodeAddr = addr 136 }