package ethchain // TODO Re write VM to use values instead of big integers? import ( "github.com/ethereum/eth-go/ethutil" "math/big" ) type Callee interface { ReturnGas(*big.Int, *State) Address() []byte } type Reference interface { Callee ethutil.RlpEncodable GetMem(*big.Int) *ethutil.Value SetMem(*big.Int, *ethutil.Value) } // Basic inline closure object which implement the 'closure' interface type Closure struct { callee Callee object Reference Script []byte State *State Gas *big.Int Value *big.Int Args []byte } // Create a new closure for the given data items func NewClosure(callee Callee, object Reference, script []byte, state *State, gas, val *big.Int) *Closure { return &Closure{callee, object, script, state, gas, val, nil} } // Retuns the x element in data slice func (c *Closure) GetMem(x *big.Int) *ethutil.Value { m := c.object.GetMem(x) if m == nil { return ethutil.EmptyValue() } return m } func (c *Closure) Get(x *big.Int) *ethutil.Value { return c.Gets(x, big.NewInt(1)) } func (c *Closure) Gets(x, y *big.Int) *ethutil.Value { if x.Int64() > int64(len(c.Script)) || y.Int64() > int64(len(c.Script)) { return ethutil.NewValue(0) } partial := c.Script[x.Int64() : x.Int64()+y.Int64()] return ethutil.NewValue(partial) } func (c *Closure) SetMem(x *big.Int, val *ethutil.Value) { c.object.SetMem(x, val) } func (c *Closure) Address() []byte { return c.object.Address() } type DebugHook func(op OpCode) func (c *Closure) Call(vm *Vm, args []byte, hook DebugHook) []byte { c.Args = args return vm.RunClosure(c, hook) } func (c *Closure) Return(ret []byte) []byte { // Return the remaining gas to the callee // If no callee is present return it to // the origin (i.e. contract or tx) if c.callee != nil { c.callee.ReturnGas(c.Gas, c.State) } else { c.object.ReturnGas(c.Gas, c.State) // TODO incase it's a POST contract we gotta serialise the contract again. // But it's not yet defined } return ret } // Implement the Callee interface func (c *Closure) ReturnGas(gas *big.Int, state *State) { // Return the gas to the closure c.Gas.Add(c.Gas, gas) } func (c *Closure) Object() Reference { return c.object } func (c *Closure) Callee() Callee { return c.callee }