Avoid blocking when broadcasting events

docs/changes.rst

@@ -8,6 +8,10 @@ This change log is used to track all major changes to Mopidy.
 v0.6.0 (in development)
 =======================
 
+**Important changes**
+
+- Pykka 0.12.3 or greater is required.
+
 **Changes**
 
 - Replace :attr:`mopidy.backends.base.Backend.uri_handlers` with

docs/installation/index.rst

@@ -25,7 +25,7 @@ Otherwise, make sure you got the required dependencies installed.
 
 - Python >= 2.6, < 3
 
-- `Pykka <http://jodal.github.com/pykka/>`_ >= 0.12
+- `Pykka <http://jodal.github.com/pykka/>`_ >= 0.12.3
 
 - GStreamer >= 0.10, with Python bindings. See :doc:`gstreamer`.
 

mopidy/backends/base/playback.py

@@ -461,18 +461,30 @@ class PlaybackController(object):
             self.current_cp_track = None
 
     def _trigger_started_playing_event(self):
+        logger.debug(u'Triggering started playing event')
         if self.current_track is None:
             return
-        for listener_ref in ActorRegistry.get_by_class(BackendListener):
-            listener_ref.proxy().started_playing(track=self.current_track)
+        ActorRegistry.broadcast({
+            'command': 'pykka_call',
+            'attr_path': ('started_playing',),
+            'args': [],
+            'kwargs': {'track': self.current_track},
+        }, target_class=BackendListener)
 
     def _trigger_stopped_playing_event(self):
         # TODO Test that this is called on next/prev/end-of-track
+        logger.debug(u'Triggering stopped playing event')
         if self.current_track is None:
             return
-        for listener_ref in ActorRegistry.get_by_class(BackendListener):
-            listener_ref.proxy().stopped_playing(
-                track=self.current_track, time_position=self.time_position)
+        ActorRegistry.broadcast({
+            'command': 'pykka_call',
+            'attr_path': ('stopped_playing',),
+            'args': [],
+            'kwargs': {
+                'track': self.current_track,
+                'time_position': self.time_position,
+            },
+        }, target_class=BackendListener)
 
 
 class BasePlaybackProvider(object):

requirements/core.txt

@@ -1 +1 @@
-Pykka >= 0.12
+Pykka >= 0.12.3