Merge IO v2 branch to bleeding edge

sdk/lib/async/stream_impl.dart

 // Copyright (c) 2012, 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 dart.async;
 
 // States shared by single/multi stream implementations.
 
 /// Initial and default state where the stream can receive and send events.
 const int _STREAM_OPEN = 0;
@@ skipping 105 matching lines @@
     _handlePendingEvents();
   }
 
   /**
    * Send or enqueue a "done" message.
    *
    * The "done" message should be sent at most once by a stream, and it
    * should be the last message sent.
    */
   void _close() {
-    if (_isClosed) throw new StateError("Sending on closed stream");
+    if (_isClosed) return;

[Mads Ager (google), 2013/02/21 10:39:02]

We should land this file on bleeding_edge. It is a general change to the async
library that is independent of dart:io v2.

[Søren Gjesse, 2013/02/21 11:44:25]

Anders did.

     _state |= _STREAM_CLOSED;
     if (!_canFireEvent) {
       // You can't enqueue an event after the Done, so make it const.
       _addPendingEvent(const _DelayedDone());
       return;
     }
     _sendDone();
     assert(!_hasPendingEvent);
   }
 
@@ skipping 166 matching lines @@
    */
   void _addListener(_StreamSubscriptionImpl subscription);
 
   /**
    * Handle a cancel requested from a [_StreamSubscriptionImpl].
    *
    * This method is called from [_StreamSubscriptionImpl.cancel].
    *
    * If an event is currently firing, the cancel is delayed
    * until after the subscribers have received the event.
+   *
+   * This will also close the stream.
    */
   void _cancel(_StreamSubscriptionImpl subscriber);
 
   /**
    * Iterate over all current subscribers and perform an action on each.
    *
    * Subscribers added during the iteration will not be visited.
    * Subscribers unsubscribed during the iteration will only be removed
    * after they have been acted on.
    *
@@ skipping 891 matching lines @@
                                      onError: this._signalError,
                                      onDone: this._close);
     } else {
       // TODO(lrn): Check why this can happen.
       if (_subscription == null) return;
       _subscription.cancel();
       _subscription = null;
     }
   }
 }