Strong html

tools/dom/src/EventStreamProvider.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of html;
 
 /**
  * A factory to expose DOM events as Streams.
  */
 class EventStreamProvider<T extends Event> {
@@ skipping 16 matching lines @@
    *
    * Or for listening to an event which will bubble through the DOM tree:
    *
    *     MediaElement.pauseEvent.forTarget(document.body).listen(...);
    *
    * See also:
    *
    * [addEventListener](http://docs.webplatform.org/wiki/dom/methods/addEventListener)
    */
   Stream<T> forTarget(EventTarget e, {bool useCapture: false}) =>
-    new _EventStream(e, _eventType, useCapture);
+    new _EventStream<T>(e, _eventType, useCapture);
 
   /**
    * Gets an [ElementEventStream] for this event type, on the specified element.
    *
    * This will always return a broadcast stream so multiple listeners can be
    * used simultaneously.
    *
    * This may be used to capture DOM events:
    *
    *     Element.keyDownEvent.forElement(element, useCapture: true).listen(...);
    *
    *     // Alternate method:
    *     Element.keyDownEvent.forElement(element).capture(...);
    *
    * Or for listening to an event which will bubble through the DOM tree:
    *
    *     MediaElement.pauseEvent.forElement(document.body).listen(...);
    *
    * See also:
    *
    * [addEventListener](http://docs.webplatform.org/wiki/dom/methods/addEventListener)
    */
   ElementStream<T> forElement(Element e, {bool useCapture: false}) {
-    return new _ElementEventStreamImpl(e, _eventType, useCapture);
+    return new _ElementEventStreamImpl<T>(e, _eventType, useCapture);
   }
 
   /**
    * Gets an [ElementEventStream] for this event type, on the list of elements.
    *
    * This will always return a broadcast stream so multiple listeners can be
    * used simultaneously.
    *
    * This may be used to capture DOM events:
    *
@@ skipping 50 matching lines @@
  * Adapter for exposing DOM events as Dart streams.
  */
 class _EventStream<T extends Event> extends Stream<T> {
   final EventTarget _target;
   final String _eventType;
   final bool _useCapture;
 
   _EventStream(this._target, this._eventType, this._useCapture);
 
   // DOM events are inherently multi-subscribers.
-  Stream<T> asBroadcastStream({void onListen(StreamSubscription subscription),
-                               void onCancel(StreamSubscription subscription)})
+  Stream<T> asBroadcastStream({void onListen(StreamSubscription<T> subscription),
+                               void onCancel(StreamSubscription<T> subscription)})
       => this;
   bool get isBroadcast => true;
 
   StreamSubscription<T> listen(void onData(T event),
       { Function onError,
         void onDone(),
         bool cancelOnError}) {
 
     return new _EventStreamSubscription<T>(
         this._target, this._eventType, onData, this._useCapture);
   }
 }
 
+bool _matchesWithAncestors(Event event, String selector) {
+  var target = event.target;
+  return target is Element ? target.matchesWithAncestors(selector) : false;
+}
+
 /**
  * Adapter for exposing DOM Element events as streams, while also allowing
  * event delegation.
  */
 class _ElementEventStreamImpl<T extends Event> extends _EventStream<T>
     implements ElementStream<T> {
   _ElementEventStreamImpl(target, eventType, useCapture) :
       super(target, eventType, useCapture);
 
   Stream<T> matches(String selector) => this.where(
-      (event) => event.target.matchesWithAncestors(selector)).map((e) {
+      (event) => _matchesWithAncestors(event, selector)).map((e) {
         e._selector = selector;
         return e;
       });
 
   StreamSubscription<T> capture(void onData(T event)) =>
     new _EventStreamSubscription<T>(
         this._target, this._eventType, onData, true);
 }
 
 /**
  * Adapter for exposing events on a collection of DOM Elements as streams,
  * while also allowing event delegation.
  */
 class _ElementListEventStreamImpl<T extends Event> extends Stream<T>
     implements ElementStream<T> {
   final Iterable<Element> _targetList;
   final bool _useCapture;
   final String _eventType;
 
   _ElementListEventStreamImpl(
       this._targetList, this._eventType, this._useCapture);
 
   Stream<T> matches(String selector) => this.where(
-      (event) => event.target.matchesWithAncestors(selector)).map((e) {
+      (event) => _matchesWithAncestors(event, selector)).map((e) {
         e._selector = selector;
         return e;
       });
 
   // Delegate all regular Stream behavior to a wrapped Stream.
   StreamSubscription<T> listen(void onData(T event),
       { Function onError,
         void onDone(),
         bool cancelOnError}) {
-    var pool = new _StreamPool.broadcast();
+    var pool = new _StreamPool<T>.broadcast();
     for (var target in _targetList) {
-      pool.add(new _EventStream(target, _eventType, _useCapture));
+      pool.add(new _EventStream<T>(target, _eventType, _useCapture));
     }
     return pool.stream.listen(onData, onError: onError, onDone: onDone,
           cancelOnError: cancelOnError);
   }
 
   StreamSubscription<T> capture(void onData(T event)) {
-    var pool = new _StreamPool.broadcast();
+    var pool = new _StreamPool<T>.broadcast();
     for (var target in _targetList) {
-      pool.add(new _EventStream(target, _eventType, true));
+      pool.add(new _EventStream<T>(target, _eventType, true));
     }
     return pool.stream.listen(onData);
   }
 
-  Stream<T> asBroadcastStream({void onListen(StreamSubscription subscription),
-                               void onCancel(StreamSubscription subscription)})
+  Stream<T> asBroadcastStream({void onListen(StreamSubscription<T> subscription),
+                               void onCancel(StreamSubscription<T> subscription)})
       => this;
   bool get isBroadcast => true;
 }
 
+// We would like this to just be EventListener<T> but that typdef cannot
+// use generics until dartbug/26276 is fixed.
+typedef _EventListener<T extends Event>(T event);
+
 class _EventStreamSubscription<T extends Event> extends StreamSubscription<T> {
   int _pauseCount = 0;
   EventTarget _target;
   final String _eventType;
-  var _onData;
+  EventListener _onData;
   final bool _useCapture;
 
-  _EventStreamSubscription(this._target, this._eventType, onData,
-      this._useCapture) : _onData = _wrapZone(onData) {
+  // TODO(jacobr): for full strong mode correctness we should write
+  // _onData = onData == null ? null : _wrapZone/*<Event, dynamic>*/((e) => onData(e as T))
+  // but that breaks 114 co19 tests as well as multiple html tests as it is reasonable
+  // to pass the wrong type of event object to an event listener as part of a
+  // test.
+  _EventStreamSubscription(this._target, this._eventType, void onData(T event),
+      this._useCapture) : _onData = _wrapZone/*<Event, dynamic>*/(onData) {
     _tryResume();
   }
 
   Future cancel() {
     if (_canceled) return null;
 
     _unlisten();
     // Clear out the target to indicate this is complete.
     _target = null;
     _onData = null;
     return null;
   }
 
   bool get _canceled => _target == null;
 
   void onData(void handleData(T event)) {
     if (_canceled) {
       throw new StateError("Subscription has been canceled.");
     }
     // Remove current event listener.
     _unlisten();
-
-    _onData = _wrapZone(handleData);
+    _onData = _wrapZone/*<Event, dynamic>*/(handleData);
     _tryResume();
   }
 
   /// Has no effect.
   void onError(Function handleError) {}
 
   /// Has no effect.
   void onDone(void handleDone()) {}
 
   void pause([Future resumeSignal]) {
@@ skipping 58 matching lines @@
 
   // Delegate all regular Stream behavior to our wrapped Stream.
   StreamSubscription<T> listen(void onData(T event),
       { Function onError,
         void onDone(),
         bool cancelOnError}) {
     return _streamController.stream.listen(onData, onError: onError,
         onDone: onDone, cancelOnError: cancelOnError);
   }
 
-  Stream<T> asBroadcastStream({void onListen(StreamSubscription subscription),
-                               void onCancel(StreamSubscription subscription)})
+  Stream<T> asBroadcastStream({void onListen(StreamSubscription<T> subscription),
+                               void onCancel(StreamSubscription<T> subscription)})
       => _streamController.stream;
 
   bool get isBroadcast => true;
 
   void add(T event) {
     if (event.type == _type) _streamController.add(event);
   }
 }
 
 class _CustomKeyEventStreamImpl extends _CustomEventStreamImpl<KeyEvent>
@@ skipping 70 matching lines @@
  * A factory to expose DOM events as streams, where the DOM event name has to
  * be determined on the fly (for example, mouse wheel events).
  */
 class _CustomEventStreamProvider<T extends Event>
     implements EventStreamProvider<T> {
 
   final _eventTypeGetter;
   const _CustomEventStreamProvider(this._eventTypeGetter);
 
   Stream<T> forTarget(EventTarget e, {bool useCapture: false}) {
-    return new _EventStream(e, _eventTypeGetter(e), useCapture);
+    return new _EventStream<T>(e, _eventTypeGetter(e), useCapture);
   }
 
   ElementStream<T> forElement(Element e, {bool useCapture: false}) {
-    return new _ElementEventStreamImpl(e, _eventTypeGetter(e), useCapture);
+    return new _ElementEventStreamImpl<T>(e, _eventTypeGetter(e), useCapture);
   }
 
   ElementStream<T> _forElementList(ElementList e,
       {bool useCapture: false}) {
-    return new _ElementListEventStreamImpl(e, _eventTypeGetter(e), useCapture);
+    return new _ElementListEventStreamImpl<T>(e, _eventTypeGetter(e), useCapture);
   }
 
   String getEventType(EventTarget target) {
     return _eventTypeGetter(target);
   }
 
   String get _eventType =>
       throw new UnsupportedError('Access type through getEventType method.');
 }