Refactored VM to two separate VMs; std & debug

Standard VM should be about 10x faster than the debug VM. Some error
checking has been removed, all of the log statements and therefor quite
some unnecessary if-statements.

ethvm/execution.go

@@ -0,0 +1,79 @@
+package ethvm
+
+import (
+	"fmt"
+	"math/big"
+
+	"github.com/ethereum/eth-go/ethstate"
+	"github.com/ethereum/eth-go/ethutil"
+)
+
+type Execution struct {
+	vm                VirtualMachine
+	closure           *Closure
+	address, input    []byte
+	gas, price, value *big.Int
+	object            *ethstate.StateObject
+}
+
+func NewExecution(vm VirtualMachine, address, input []byte, gas, gasPrice, value *big.Int) *Execution {
+	return &Execution{vm: vm, address: address, input: input, gas: gas, price: gasPrice, value: value}
+}
+
+func (self *Execution) Addr() []byte {
+	return self.address
+}
+
+func (self *Execution) Exec(codeAddr []byte, caller ClosureRef) (ret []byte, err error) {
+	env := self.vm.Env()
+
+	snapshot := env.State().Copy()
+
+	msg := env.State().Manifest().AddMessage(&ethstate.Message{
+		To: self.address, From: caller.Address(),
+		Input:  self.input,
+		Origin: env.Origin(),
+		Block:  env.BlockHash(), Timestamp: env.Time(), Coinbase: env.Coinbase(), Number: env.BlockNumber(),
+		Value: self.value,
+	})
+
+	object := caller.Object()
+	if object.Balance.Cmp(self.value) < 0 {
+		caller.ReturnGas(self.gas, self.price)
+
+		err = fmt.Errorf("Insufficient funds to transfer value. Req %v, has %v", self.value, object.Balance)
+	} else {
+		stateObject := env.State().GetOrNewStateObject(self.address)
+		self.object = stateObject
+
+		caller.Object().SubAmount(self.value)
+		stateObject.AddAmount(self.value)
+
+		// Precompiled contracts (address.go) 1, 2 & 3.
+		if p := Precompiled[ethutil.BigD(codeAddr).Uint64()]; p != nil {
+			if self.gas.Cmp(p.Gas) >= 0 {
+				ret = p.Call(self.input)
+			}
+		} else {
+			if self.vm.Depth() == MaxCallDepth {
+				return nil, fmt.Errorf("Max call depth exceeded (%d)", MaxCallDepth)
+			}
+
+			// Retrieve the executing code
+			code := env.State().GetCode(codeAddr)
+
+			// Create a new callable closure
+			c := NewClosure(msg, caller, stateObject, code, self.gas, self.price)
+			// Executer the closure and get the return value (if any)
+			ret, _, err = c.Call(self.vm, self.input)
+
+			msg.Output = ret
+		}
+	}
+
+	if err != nil {
+		env.State().Set(snapshot)
+	}
+
+	return
+}