Refactor the message serialization code a bit so we can start playing with it for JS interop purpos…

lib/isolate/frog/messages.dart

Index: lib/isolate/frog/messages.dart
diff --git a/lib/isolate/frog/messages.dart b/lib/isolate/frog/messages.dart
index 595db85d017dd8cac1f7067f1111c58be94241d5..b8a3825300a4bcf823bda1417b4dc76cd23a7864 100644
--- a/lib/isolate/frog/messages.dart
+++ b/lib/isolate/frog/messages.dart
@@ -7,147 +7,45 @@
 /** Serialize [message] (or simulate serialization). */
 _serializeMessage(message) {
   if (_globalState.needSerialization) {
-    return new _Serializer().traverse(message);
+    return new _JsSerializer().traverse(message);
   } else {
-    return new _Copier().traverse(message);
+    return new _JsCopier().traverse(message);
   }
 }
 
 /** Deserialize [message] (or simulate deserialization). */
 _deserializeMessage(message) {
   if (_globalState.needSerialization) {
-    return new _Deserializer().deserialize(message);
+    return new _JsDeserializer().deserialize(message);
   } else {
     // Nothing more to do.
     return message;
   }
 }
 
-/** Abstract visitor for dart objects that can be sent as isolate messages. */
-class _MessageTraverser {
+class _JsSerializer extends _Serializer {
 
-  List _taggedObjects;
+  _JsSerializer() : super() { _visited = new _JsVisitedMap(); }
 
-  _MessageTraverser();
-
-  /** Visitor's entry point. */
-  traverse(var x) {
-    if (isPrimitive(x)) return visitPrimitive(x);
-    _taggedObjects = new List();
-    var result;
-    try {
-      result = _dispatch(x);
-    } finally {
-      _cleanup();
-    }
-    return result;
-  }
-
-  /** Remove all information injected in the native objects by this visitor. */
-  void _cleanup() {
-    int len = _taggedObjects.length;
-    for (int i = 0; i < len; i++) {
-      _clearAttachedInfo(_taggedObjects[i]);
-    }
-    _taggedObjects = null;
-  }
-
-  /** Injects into the native object some information used by the visitor. */
-  void _attachInfo(var o, var info) {
-    _taggedObjects.add(o);
-    _setAttachedInfo(o, info);
-  }
-
-  /** Retrieves any information stored in the native object [o]. */
-  _getInfo(var o) {
-    return _getAttachedInfo(o);
-  }
-
-  _dispatch(var x) {
-    if (isPrimitive(x)) return visitPrimitive(x);
-    if (x is List) return visitList(x);
-    if (x is Map) return visitMap(x);
+  visitSendPort(SendPort x) {
     if (x is _NativeJsSendPort) return visitNativeJsSendPort(x);
     if (x is _WorkerSendPort) return visitWorkerSendPort(x);
     if (x is _BufferingSendPort) return visitBufferingSendPort(x);
-    // TODO(floitsch): make this a real exception. (which one)?
-    throw "Message serialization: Illegal value $x passed";
-  }
-
-  abstract visitPrimitive(x);
-  abstract visitList(List x);
-  abstract visitMap(Map x);
-  abstract visitNativeJsSendPort(_NativeJsSendPort x);
-  abstract visitWorkerSendPort(_WorkerSendPort x);
-  abstract visitBufferingSendPort(_BufferingSendPort x);
-
-  _clearAttachedInfo(var o) native
-      "o['__MessageTraverser__attached_info__'] = (void 0);";
-
-  _setAttachedInfo(var o, var info) native
-      "o['__MessageTraverser__attached_info__'] = info;";
-
-  _getAttachedInfo(var o) native
-      "return o['__MessageTraverser__attached_info__'];";
-
-  _visitNativeOrWorkerPort(SendPort p) {
-    if (p is _NativeJsSendPort) return visitNativeJsSendPort(p);
-    if (p is _WorkerSendPort) return visitWorkerSendPort(p);
     throw "Illegal underlying port $p";
   }
 
-  static bool isPrimitive(x) {
-    return (x === null) || (x is String) || (x is num) || (x is bool);
-  }
-}
-
-
-/** A visitor that recursively copies a message. */
-class _Copier extends _MessageTraverser {
-  _Copier() : super();
-
-  visitPrimitive(x) => x;
-
-  List visitList(List list) {
-    List copy = _getInfo(list);
-    if (copy !== null) return copy;
-
-    int len = list.length;
-
-    // TODO(floitsch): we loose the generic type of the List.
-    copy = new List(len);
-    _attachInfo(list, copy);
-    for (int i = 0; i < len; i++) {
-      copy[i] = _dispatch(list[i]);
-    }
-    return copy;
-  }
-
-  Map visitMap(Map map) {
-    Map copy = _getInfo(map);
-    if (copy !== null) return copy;
-
-    // TODO(floitsch): we loose the generic type of the map.
-    copy = new Map();
-    _attachInfo(map, copy);
-    map.forEach((key, val) {
-      copy[_dispatch(key)] = _dispatch(val);
-    });
-    return copy;
-  }
-
-  SendPort visitNativeJsSendPort(_NativeJsSendPort port) {
-    return new _NativeJsSendPort(port._receivePort, port._isolateId);
+  visitNativeJsSendPort(_NativeJsSendPort port) {
+    return ['sendport', _globalState.currentManagerId,
+        port._isolateId, port._receivePort._id];
   }
 
-  SendPort visitWorkerSendPort(_WorkerSendPort port) {
-    return new _WorkerSendPort(
-        port._workerId, port._isolateId, port._receivePortId);
+  visitWorkerSendPort(_WorkerSendPort port) {
+    return ['sendport', port._workerId, port._isolateId, port._receivePortId];
   }
 
-  SendPort visitBufferingSendPort(_BufferingSendPort port) {
+  visitBufferingSendPort(_BufferingSendPort port) {
     if (port._port != null) {
-      return _visitNativeOrWorkerPort(port._port);
+      return visitSendPort(port._port);
     } else {
       // TODO(floitsch): Use real exception (which one?).
       throw
@@ -155,51 +53,33 @@ class _Copier extends _MessageTraverser {
           " ports are resolved at this point.";
     }
   }
-}
-
-/** Visitor that serializes a message as a JSON array. */
-class _Serializer extends _MessageTraverser {
-  int _nextFreeRefId = 0;
-
-  _Serializer() : super();
 
-  visitPrimitive(x) => x;
+}
 
-  visitList(List list) {
-    int copyId = _getInfo(list);
-    if (copyId !== null) return ['ref', copyId];
 
-    int id = _nextFreeRefId++;
-    _attachInfo(list, id);
-    var jsArray = _serializeList(list);
-    // TODO(floitsch): we are losing the generic type.
-    return ['list', id, jsArray];
-  }
+class _JsCopier extends _Copier {
 
-  visitMap(Map map) {
-    int copyId = _getInfo(map);
-    if (copyId !== null) return ['ref', copyId];
+  _JsCopier() : super() { _visited = new _JsVisitedMap(); }
 
-    int id = _nextFreeRefId++;
-    _attachInfo(map, id);
-    var keys = _serializeList(map.getKeys());
-    var values = _serializeList(map.getValues());
-    // TODO(floitsch): we are losing the generic type.
-    return ['map', id, keys, values];
+  visitSendPort(SendPort x) {
+    if (x is _NativeJsSendPort) return visitNativeJsSendPort(x);
+    if (x is _WorkerSendPort) return visitWorkerSendPort(x);
+    if (x is _BufferingSendPort) return visitBufferingSendPort(x);
+    throw "Illegal underlying port $p";
   }
 
-  visitNativeJsSendPort(_NativeJsSendPort port) {
-    return ['sendport', _globalState.currentManagerId,
-        port._isolateId, port._receivePort._id];
+  SendPort visitNativeJsSendPort(_NativeJsSendPort port) {
+    return new _NativeJsSendPort(port._receivePort, port._isolateId);
   }
 
-  visitWorkerSendPort(_WorkerSendPort port) {
-    return ['sendport', port._workerId, port._isolateId, port._receivePortId];
+  SendPort visitWorkerSendPort(_WorkerSendPort port) {
+    return new _WorkerSendPort(
+        port._workerId, port._isolateId, port._receivePortId);
   }
 
-  visitBufferingSendPort(_BufferingSendPort port) {
+  SendPort visitBufferingSendPort(_BufferingSendPort port) {
     if (port._port != null) {
-      return _visitNativeOrWorkerPort(port._port);
+      return visitSendPort(port._port);
     } else {
       // TODO(floitsch): Use real exception (which one?).
       throw
@@ -208,82 +88,11 @@ class _Serializer extends _MessageTraverser {
     }
   }
 
-  _serializeList(List list) {
-    int len = list.length;
-    var result = new List(len);
-    for (int i = 0; i < len; i++) {
-      result[i] = _dispatch(list[i]);
-    }
-    return result;
-  }
 }
 
-/** Deserializes arrays created with [_Serializer]. */
-class _Deserializer {
-  Map<int, Dynamic> _deserialized;
-
-  _Deserializer();
-
-  static bool isPrimitive(x) {
-    return (x === null) || (x is String) || (x is num) || (x is bool);
-  }
-
-  deserialize(x) {
-    if (isPrimitive(x)) return x;
-    // TODO(floitsch): this should be new HashMap<int, var|Dynamic>()
-    _deserialized = new HashMap();
-    return _deserializeHelper(x);
-  }
-
-  _deserializeHelper(x) {
-    if (isPrimitive(x)) return x;
-    assert(x is List);
-    switch (x[0]) {
-      case 'ref': return _deserializeRef(x);
-      case 'list': return _deserializeList(x);
-      case 'map': return _deserializeMap(x);
-      case 'sendport': return _deserializeSendPort(x);
-      // TODO(floitsch): Use real exception (which one?).
-      default: throw "Unexpected serialized object";
-    }
-  }
-
-  _deserializeRef(List x) {
-    int id = x[1];
-    var result = _deserialized[id];
-    assert(result !== null);
-    return result;
-  }
+class _JsDeserializer extends _Deserializer {
 
-  List _deserializeList(List x) {
-    int id = x[1];
-    // We rely on the fact that Dart-lists are directly mapped to Js-arrays.
-    List dartList = x[2];
-    _deserialized[id] = dartList;
-    int len = dartList.length;
-    for (int i = 0; i < len; i++) {
-      dartList[i] = _deserializeHelper(dartList[i]);
-    }
-    return dartList;
-  }
-
-  Map _deserializeMap(List x) {
-    Map result = new Map();
-    int id = x[1];
-    _deserialized[id] = result;
-    List keys = x[2];
-    List values = x[3];
-    int len = keys.length;
-    assert(len == values.length);
-    for (int i = 0; i < len; i++) {
-      var key = _deserializeHelper(keys[i]);
-      var value = _deserializeHelper(values[i]);
-      result[key] = value;
-    }
-    return result;
-  }
-
-  SendPort _deserializeSendPort(List x) {
+  SendPort deserializeSendPort(List x) {
     int managerId = x[1];
     int isolateId = x[2];
     int receivePortId = x[3];
@@ -298,19 +107,58 @@ class _Deserializer {
       return new _WorkerSendPort(managerId, isolateId, receivePortId);
     }
   }
+
+}
+
+class _JsVisitedMap implements _MessageTraverserVisitedMap {
+  List tagged;
+
+  /** Retrieves any information stored in the native object [object]. */
+  operator[](var object) {
+    return _getAttachedInfo(object);
+  }
+
+  /** Injects some information into the native [object]. */
+  void operator[]=(var object, var info) {
+    tagged.add(object);
+    _setAttachedInfo(object, info);
+  }
+
+  /** Get ready to rumble. */
+  void reset() {
+    assert(tagged == null);
+    tagged = new List();
+  }
+
+  /** Remove all information injected in the native objects. */
+  cleanup() {
+    for (int i = 0, length = tagged.length; i < length; i++) {
+      _clearAttachedInfo(tagged[i]);
+    }
+    tagged = null;
+  }
+
+  _clearAttachedInfo(var o) native
+      "o['__MessageTraverser__attached_info__'] = (void 0);";
+
+  _setAttachedInfo(var o, var info) native
+      "o['__MessageTraverser__attached_info__'] = info;";
+
+  _getAttachedInfo(var o) native
+      "return o['__MessageTraverser__attached_info__'];";
 }
 
 // only visible for testing purposes
 // TODO(sigmund): remove once we can disable privacy for testing (bug #1882)
 class TestingOnly {
   static copy(x) {
-    return new _Copier().traverse(x);
+    return new _JsCopier().traverse(x);
   }
 
   // only visible for testing purposes
   static serialize(x) {
-    _Serializer serializer = new _Serializer();
-    _Deserializer deserializer = new _Deserializer();
+    _Serializer serializer = new _JsSerializer();
+    _Deserializer deserializer = new _JsDeserializer();
     return deserializer.deserialize(serializer.traverse(x));
   }
 }