120 lines
2.7 KiB
Go
120 lines
2.7 KiB
Go
package ethvm
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// TODO Re write VM to use values instead of big integers?
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import (
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"math/big"
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"github.com/ethereum/eth-go/ethstate"
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"github.com/ethereum/eth-go/ethutil"
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)
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type ClosureRef interface {
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ReturnGas(*big.Int, *big.Int)
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Address() []byte
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Object() *ethstate.StateObject
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GetStorage(*big.Int) *ethutil.Value
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SetStorage(*big.Int, *ethutil.Value)
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}
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// Basic inline closure object which implement the 'closure' interface
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type Closure struct {
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caller ClosureRef
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object *ethstate.StateObject
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Code []byte
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message *ethstate.Message
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Gas, UsedGas, Price *big.Int
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Args []byte
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}
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// Create a new closure for the given data items
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func NewClosure(msg *ethstate.Message, caller ClosureRef, object *ethstate.StateObject, code []byte, gas, price *big.Int) *Closure {
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c := &Closure{message: msg, caller: caller, object: object, Code: code, Args: nil}
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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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// 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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// Retuns the x element in data slice
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func (c *Closure) GetStorage(x *big.Int) *ethutil.Value {
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m := c.object.GetStorage(x)
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if m == nil {
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return ethutil.EmptyValue()
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}
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return m
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}
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func (c *Closure) Get(x *big.Int) *ethutil.Value {
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return c.Gets(x, big.NewInt(1))
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}
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func (c *Closure) Gets(x, y *big.Int) *ethutil.Value {
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if x.Int64() >= int64(len(c.Code)) || y.Int64() >= int64(len(c.Code)) {
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return ethutil.NewValue(0)
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}
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partial := c.Code[x.Int64() : x.Int64()+y.Int64()]
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return ethutil.NewValue(partial)
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}
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func (c *Closure) SetStorage(x *big.Int, val *ethutil.Value) {
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c.object.SetStorage(x, val)
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}
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func (c *Closure) Address() []byte {
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return c.object.Address()
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}
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func (c *Closure) Call(vm *Vm, args []byte) ([]byte, *big.Int, error) {
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c.Args = args
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ret, err := vm.RunClosure(c)
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return ret, c.UsedGas, err
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}
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func (c *Closure) 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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func (c *Closure) UseGas(gas *big.Int) bool {
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if c.Gas.Cmp(gas) < 0 {
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return false
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}
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// Sub the amount of gas from the remaining
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c.Gas.Sub(c.Gas, gas)
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c.UsedGas.Add(c.UsedGas, gas)
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return true
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}
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// Implement the caller interface
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func (c *Closure) ReturnGas(gas, price *big.Int) {
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// Return the gas to the closure
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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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func (c *Closure) Object() *ethstate.StateObject {
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return c.object
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}
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func (c *Closure) Caller() ClosureRef {
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return c.caller
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}
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