Updated VM & added helper methods to state

* VM BALANCE opcode updated to pop 1 item and use that to retrieve the
  address' balance
* GetBalance and GetNonce on state that'll always return something valid

2 files changed, 101 insertions, 70 deletions

diff --git a/ethchain/state.go b/ethchain/state.go
index d93ab3e01..6d45c9e32 100644
--- a/ethchain/state.go
+++ b/ethchain/state.go
@@ -26,79 +26,36 @@ func NewState(trie *ethtrie.Trie) *State {
 	return &State{trie: trie, stateObjects: make(map[string]*StateObject), manifest: NewManifest()}
 }
 
-// Resets the trie and all siblings
-func (s *State) Reset() {
-	s.trie.Undo()
-
-	// Reset all nested states
-	for _, stateObject := range s.stateObjects {
-		if stateObject.state == nil {
-			continue
-		}
-
-		//stateObject.state.Reset()
-		stateObject.Reset()
-	}
-
-	s.Empty()
+// Iterate over each storage address and yield callback
+func (s *State) EachStorage(cb ethtrie.EachCallback) {
+	it := s.trie.NewIterator()
+	it.Each(cb)
 }
 
-// Syncs the trie and all siblings
-func (s *State) Sync() {
-	// Sync all nested states
-	for _, stateObject := range s.stateObjects {
-		s.UpdateStateObject(stateObject)
-
-		if stateObject.state == nil {
-			continue
-		}
-
-		stateObject.state.Sync()
+// Retrieve the balance from the given address or 0 if object not found
+func (self *State) GetBalance(addr []byte) *big.Int {
+	stateObject := self.GetStateObject(addr)
+	if stateObject != nil {
+		return stateObject.Amount
 	}
 
-	s.trie.Sync()
-
-	s.Empty()
-}
-
-func (self *State) Empty() {
-	self.stateObjects = make(map[string]*StateObject)
+	return ethutil.Big0
 }
 
-func (self *State) Update() {
-	for _, stateObject := range self.stateObjects {
-		if stateObject.remove {
-			self.DeleteStateObject(stateObject)
-		} else {
-			stateObject.Sync()
-
-			self.UpdateStateObject(stateObject)
-		}
-	}
-
-	// FIXME trie delete is broken
-	valid, t2 := ethtrie.ParanoiaCheck(self.trie)
-	if !valid {
-		self.trie = t2
+func (self *State) GetNonce(addr []byte) uint64 {
+	stateObject := self.GetStateObject(addr)
+	if stateObject != nil {
+		return stateObject.Nonce
 	}
-}
 
-// Purges the current trie.
-func (s *State) Purge() int {
-	return s.trie.NewIterator().Purge()
+	return 0
 }
 
-func (s *State) EachStorage(cb ethtrie.EachCallback) {
-	it := s.trie.NewIterator()
-	it.Each(cb)
-}
-
-func (self *State) ResetStateObject(stateObject *StateObject) {
-	delete(self.stateObjects, string(stateObject.Address()))
-
-	stateObject.state.Reset()
-}
+//
+// Setting, updating & deleting state object methods
+//
 
+// Update the given state object and apply it to state trie
 func (self *State) UpdateStateObject(stateObject *StateObject) {
 	addr := stateObject.Address()
 
@@ -109,12 +66,14 @@ func (self *State) UpdateStateObject(stateObject *StateObject) {
 	self.manifest.AddObjectChange(stateObject)
 }
 
+// Delete the given state object and delete it from the state trie
 func (self *State) DeleteStateObject(stateObject *StateObject) {
 	self.trie.Delete(string(stateObject.Address()))
 
 	delete(self.stateObjects, string(stateObject.Address()))
 }
 
+// Retrieve a state object given my the address. Nil if not found
 func (self *State) GetStateObject(addr []byte) *StateObject {
 	stateObject := self.stateObjects[string(addr)]
 	if stateObject != nil {
@@ -132,6 +91,7 @@ func (self *State) GetStateObject(addr []byte) *StateObject {
 	return stateObject
 }
 
+// Retrieve a state object or create a new state object if nil
 func (self *State) GetOrNewStateObject(addr []byte) *StateObject {
 	stateObject := self.GetStateObject(addr)
 	if stateObject == nil {
@@ -141,6 +101,7 @@ func (self *State) GetOrNewStateObject(addr []byte) *StateObject {
 	return stateObject
 }
 
+// Create a state object whether it exist in the trie or not
 func (self *State) NewStateObject(addr []byte) *StateObject {
 	statelogger.Infof("(+) %x\n", addr)
 
@@ -150,10 +111,15 @@ func (self *State) NewStateObject(addr []byte) *StateObject {
 	return stateObject
 }
 
+// Deprecated
 func (self *State) GetAccount(addr []byte) *StateObject {
 	return self.GetOrNewStateObject(addr)
 }
 
+//
+// Setting, copying of the state methods
+//
+
 func (s *State) Cmp(other *State) bool {
 	return s.trie.Cmp(other.trie)
 }
@@ -181,14 +147,67 @@ func (self *State) Set(state *State) {
 	//*self = *state
 }
 
-func (s *State) Put(key, object []byte) {
-	s.trie.Update(string(key), string(object))
-}
-
 func (s *State) Root() interface{} {
 	return s.trie.Root
 }
 
+// Resets the trie and all siblings
+func (s *State) Reset() {
+	s.trie.Undo()
+
+	// Reset all nested states
+	for _, stateObject := range s.stateObjects {
+		if stateObject.state == nil {
+			continue
+		}
+
+		//stateObject.state.Reset()
+		stateObject.Reset()
+	}
+
+	s.Empty()
+}
+
+// Syncs the trie and all siblings
+func (s *State) Sync() {
+	// Sync all nested states
+	for _, stateObject := range s.stateObjects {
+		s.UpdateStateObject(stateObject)
+
+		if stateObject.state == nil {
+			continue
+		}
+
+		stateObject.state.Sync()
+	}
+
+	s.trie.Sync()
+
+	s.Empty()
+}
+
+func (self *State) Empty() {
+	self.stateObjects = make(map[string]*StateObject)
+}
+
+func (self *State) Update() {
+	for _, stateObject := range self.stateObjects {
+		if stateObject.remove {
+			self.DeleteStateObject(stateObject)
+		} else {
+			stateObject.Sync()
+
+			self.UpdateStateObject(stateObject)
+		}
+	}
+
+	// FIXME trie delete is broken
+	valid, t2 := ethtrie.ParanoiaCheck(self.trie)
+	if !valid {
+		self.trie = t2
+	}
+}
+
 // Object manifest
 //
 // The object manifest is used to keep changes to the state so we can keep track of the changes
diff --git a/ethchain/vm.go b/ethchain/vm.go
index c63b5392f..f57d6a751 100644
--- a/ethchain/vm.go
+++ b/ethchain/vm.go
@@ -452,13 +452,26 @@ func (vm *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 			data := ethcrypto.Sha3Bin(mem.Get(offset.Int64(), size.Int64()))
 
 			stack.Push(ethutil.BigD(data))
+
+			vm.Printf(" => %x", data)
 			// 0x30 range
 		case ADDRESS:
 			stack.Push(ethutil.BigD(closure.Object().Address()))
+
+			vm.Printf(" => %x", closure.Object().Address())
 		case BALANCE:
-			stack.Push(closure.object.Amount)
+			require(1)
+
+			addr := stack.Pop().Bytes()
+			balance := vm.state.GetBalance(addr)
+
+			stack.Push(balance)
+
+			vm.Printf(" => %v (%x)", balance, addr)
 		case ORIGIN:
 			stack.Push(ethutil.BigD(vm.vars.Origin))
+
+			vm.Printf(" => %v", vm.vars.Origin)
 		case CALLER:
 			caller := closure.caller.Address()
 			stack.Push(ethutil.BigD(caller))
@@ -712,7 +725,7 @@ func (vm *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 
 				stack.Push(ethutil.BigFalse)
 			} else {
-				//snapshot := vm.state.Copy()
+				snapshot := vm.state.Copy()
 
 				stateObject := vm.state.GetOrNewStateObject(addr.Bytes())
 
@@ -728,8 +741,7 @@ func (vm *Vm) RunClosure(closure *Closure) (ret []byte, err error) {
 
 					vmlogger.Debugf("Closure execution failed. %v\n", err)
 
-					//vm.state.Set(snapshot)
-					vm.state.ResetStateObject(stateObject)
+					vm.state.Set(snapshot)
 				} else {
 					stack.Push(ethutil.BigTrue)