added a transfer method to vm env

vm/environment.go

@@ -1,6 +1,7 @@
 package vm
 
 import (
+	"errors"
 	"math/big"
 
 	"github.com/ethereum/eth-go/ethstate"
@@ -18,9 +19,28 @@ type Environment interface {
 	Difficulty() *big.Int
 	BlockHash() []byte
 	GasLimit() *big.Int
+	Transfer(from, to Account, amount *big.Int) error
 }
 
 type Object interface {
 	GetStorage(key *big.Int) *ethutil.Value
 	SetStorage(key *big.Int, value *ethutil.Value)
 }
+
+type Account interface {
+	SubBalance(amount *big.Int)
+	AddBalance(amount *big.Int)
+	Balance() *big.Int
+}
+
+// generic transfer method
+func Transfer(from, to Account, amount *big.Int) error {
+	if from.Balance().Cmp(amount) < 0 {
+		return errors.New("Insufficient balance in account")
+	}
+
+	from.SubBalance(amount)
+	to.AddBalance(amount)
+
+	return nil
+}

vm/execution.go

@@ -48,17 +48,17 @@ func (self *Execution) exec(code, caddr []byte, caller ClosureRef) (ret []byte,
 		Value: self.value,
 	})
 
-	object := caller.Object()
-	if object.Balance.Cmp(self.value) < 0 {
+	from, to := caller.Object(), env.State().GetOrNewStateObject(self.address)
+	err = env.Transfer(from, to, self.value)
+	if err != nil {
 		caller.ReturnGas(self.Gas, self.price)
 
-		err = fmt.Errorf("Insufficient funds to transfer value. Req %v, has %v", self.value, object.Balance)
+		err = fmt.Errorf("Insufficient funds to transfer value. Req %v, has %v", self.value, from.Balance)
 	} else {
-		stateObject := env.State().GetOrNewStateObject(self.address)
-		self.object = stateObject
+		self.object = to
 
-		caller.Object().SubAmount(self.value)
-		stateObject.AddAmount(self.value)
+		//caller.Object().SubAmount(self.value)
+		//stateObject.AddAmount(self.value)
 
 		// Pre-compiled contracts (address.go) 1, 2 & 3.
 		naddr := ethutil.BigD(caddr).Uint64()
@@ -69,7 +69,7 @@ func (self *Execution) exec(code, caddr []byte, caller ClosureRef) (ret []byte,
 			}
 		} else {
 			// Create a new callable closure
-			c := NewClosure(msg, caller, stateObject, code, self.Gas, self.price)
+			c := NewClosure(msg, caller, to, code, self.Gas, self.price)
 			c.exe = self
 
 			if self.vm.Depth() == MaxCallDepth {

vm/vm.go

@@ -692,7 +692,7 @@ func (self *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 
 			receiver := self.env.State().GetOrNewStateObject(stack.Pop().Bytes())
 
-			receiver.AddAmount(closure.object.Balance)
+			receiver.AddAmount(closure.object.Balance())
 
 			closure.object.MarkForDeletion()