Add support for JS->Dart and Dart->dart via *PortSync.

lib/dom/templates/html/frog/html_frog.darttemplate

Index: lib/dom/templates/html/frog/html_frog.darttemplate
diff --git a/lib/dom/templates/html/frog/html_frog.darttemplate b/lib/dom/templates/html/frog/html_frog.darttemplate
index b7631bfdfae7834d0ff11e716045d74c0e72dd6a..ef0cd9497cf1746d8a1568f19c162d7448a3753e 100644
--- a/lib/dom/templates/html/frog/html_frog.darttemplate
+++ b/lib/dom/templates/html/frog/html_frog.darttemplate
@@ -51,8 +51,31 @@ class _HTMLElementImpl extends _ElementImpl native "*HTMLElement" {
 
 // TODO(vsm): Move this to a separate Isolates.dart file.
 _serialize(var message) {
-  // TODO(kasperl): Specialize the serializer.
-  return new _Serializer().traverse(message);
+  return new _JsSerializer().traverse(message);
+}
+
+class _JsSerializer extends _Serializer {
+
+  visitSendPortSync(SendPortSync x) {
+    if (x is _JsSendPortSync) return visitJsSendPortSync(x);
+    if (x is _LocalSendPortSync) return visitLocalSendPortSync(x);
+    if (x is _RemoteSendPortSync) return visitRemoteSendPortSync(x);
+    throw "Illegal underlying port $x";
+  }
+
+  visitJsSendPortSync(_JsSendPortSync x) {
+    return [ 'sendport', 'nativejs', x._id ];
+  }
+
+  visitLocalSendPortSync(_LocalSendPortSync x) {
+    return [ 'sendport', 'dart2js',
+             ReceivePortSync._isolateId, x._receivePort._portId ];
+  }
+
+  visitRemoteSendPortSync(_RemoteSendPortSync x) {
+    return [ 'sendport', 'dart2js',
+             x._receivePort._isolateId, x._receivePort._portId ];
+  }
 }
 
 _deserialize(var message) {
@@ -62,12 +85,23 @@ _deserialize(var message) {
 class _JsDeserializer extends _Deserializer {
 
   deserializeSendPort(List x) {
-    num id = x[1];
-    return new _JsSendPortSync(id);
+    String tag = x[1];
+    switch (tag) {
+      case 'nativejs':
+        num id = x[2];
+        return new _JsSendPortSync(id);
+      case 'dart2js':
+        num isolateId = x[2];
+        num portId = x[3];
+        return ReceivePortSync._lookup(isolateId, portId);
+      default:
+        throw 'Illegal SendPortSync type: $tag';
+    }
   }
 
 }
 
+// The receiver is JS.
 class _JsSendPortSync implements SendPortSync {
 
   num _id;
@@ -81,3 +115,143 @@ class _JsSendPortSync implements SendPortSync {
   }
 
 }
+
+// TODO(vsm): Handle Dartium isolates.
+// The receiver is a different Dart isolate, compiled to JS.
+class _RemoteSendPortSync implements SendPortSync {
+
+  int _isolateId;
+  int _portId;
+  _RemoteSendPortSync(this._isolateId, this._portId);
+
+  callSync(var message) {
+    var serialized = _serialize(message);
+    var result = _call(_isolateId, _portId, serialized);
+    return _deserialize(result);
+  }
+
+  static _call(int isolateId, int portId, var message) {
+    var target = 'dart-port-$isolateId-$portId'; 
+    // TODO(vsm): Make this re-entrant.
+    // TODO(vsm): Set this up set once, on the first call.
+    var source = '$target-result';
+    var result = null;
+    var listener = (TextEvent e) {
+      result = JSON.parse(e.data);
+    };
+    window.on[source].add(listener);
+    _dispatchEvent(target, [source, message]);
+    window.on[source].remove(listener);
+    return result;
+  }
+}
+
+// The receiver is in the same Dart isolate, compiled to JS.
+class _LocalSendPortSync implements SendPortSync {
+
+  ReceivePortSync _receivePort;
+
+  _LocalSendPortSync._internal(this._receivePort);
+
+  callSync(var message) {
+    // TODO(vsm): Do a more efficient deep copy.
+    var copy = _deserialize(_serialize(message));
+    var result = _receivePort._callback(copy);
+    return _deserialize(_serialize(result));
+  }
+}
+
+// TODO(vsm): Move this to dart:isolate.  This will take some
+// refactoring as there are dependences here on the DOM.  Users
+// interact with this class (or interface if we change it) directly -
+// new ReceivePortSync.  I think most of the DOM logic could be
+// delayed until the corresponding SendPort is registered on the
+// window.
+
+// A Dart2JS ReceivePortSync (tagged 'dart2js' when serialized) is
+// identifiable / resolvable by the combination of its isolateid and
+// portid.  When a corresponding SendPort is used within the same
+// isolate, the _portMap below can be used to obtain the
+// ReceivePortSync directly.  Across isolates (or from JS), an
+// EventListener can be used to communicate with the port indirectly.
+class ReceivePortSync {
+
+  static Map<int, ReceivePortSync> _portMap;
+  static int _portIdCount;
+  static int _cachedIsolateId;
+
+  num _portId;
+  Function _callback;
+  EventListener _listener;
+
+  ReceivePortSync() {
+    if (_portIdCount == null) {
+      _portIdCount = 0;
+      _portMap = new Map<int, ReceivePortSync>();
+    }
+    _portId = _portIdCount++;
+    _portMap[_portId] = this;
+  }
+
+  static int get _isolateId() {
+    // TODO(vsm): Make this coherent with existing isolate code.
+    if (_cachedIsolateId == null) {
+      _cachedIsolateId = _getNewIsolateId();      
+    }
+    return _cachedIsolateId;
+  }
+
+  static int _getNewIsolateId() native @'''
+    if (!window.$dart$isolate$counter) {
+      window.$dart$isolate$counter = 1;
+    }
+    return window.$dart$isolate$counter++;
+''';
+
+  static String _getListenerName(isolateId, portId) =>
+      'dart-port-$isolateId-$portId'; 
+  String get _listenerName() => _getListenerName(_isolateId, _portId);
+
+  void receive(callback(var message)) {
+    // Clear old listener.
+    if (_callback != null) {
+      window.on[_listenerName].remove(_listener);
+    }
+
+    _callback = callback;
+
+    // Install new listener.
+    var sendport = toSendPort();
+    _listener = (TextEvent e) {
+      var data = JSON.parse(e.data);
+      var replyTo = data[0];
+      var message = _deserialize(data[1]);
+      var result = sendport.callSync(message);
+      _dispatchEvent(replyTo, _serialize(result));
+    };
+    window.on[_listenerName].add(_listener);
+  }
+
+  void close() {
+    _portMap.remove(_portId);
+    window.on[_listenerName].remove(_listener);
+  }
+
+  SendPortSync toSendPort() {
+    return new _LocalSendPortSync._internal(this);
+  }
+
+  static SendPortSync _lookup(int isolateId, int portId) {
+    if (isolateId == _isolateId) {
+      return _portMap[portId].toSendPort();
+    } else {
+      return new _RemoteSendPortSync(isolateId, portId);
+    }
+  }
+}
+
+void _dispatchEvent(String receiver, var message) {
+  var event = document.$dom_createEvent('TextEvent');
+  event.initTextEvent(receiver, false, false, window, JSON.stringify(message));
+  window.$dom_dispatchEvent(event);
+}