audio: Add position_changed event to know when seeks happen

mopidy/audio/actor.py

@@ -180,6 +180,8 @@ class Audio(pykka.ThreadingActor):
         queue.set_property('max-size-time', 5 * gst.SECOND)
         queue.set_property('min-threshold-time', 3 * gst.SECOND)
 
+        queue.get_pad('src').add_event_probe(self._on_pad_event)
+
         output.add(user_output)
         output.add(queue)
 
@@ -294,6 +296,13 @@ class Audio(pykka.ThreadingActor):
         self._disconnect(bus, 'message')
         bus.remove_signal_watch()
 
+    def _on_pad_event(self, pad, event):
+        if event.type == gst.EVENT_NEWSEGMENT:
+            # update, rate, format, start, stop, position
+            position = event.parse_new_segment()[5] // gst.MSECOND
+            AudioListener.send('position_changed', position=position)
+        return True
+
     def _on_message(self, bus, message):
         if (message.type == gst.MESSAGE_STATE_CHANGED
                 and message.src == self._playbin):

mopidy/audio/listener.py

@@ -37,6 +37,16 @@ class AudioListener(listener.Listener):
         """
         pass
 
+    def position_changed(self, position_changed):
+        """
+        Called whenever the position of the stream changes.
+
+        *MAY* be implemented by actor.
+
+        :param int position: Position in milliseconds.
+        """
+        pass
+
     def state_changed(self, old_state, new_state):
         """
         Called after the playback state have changed.

tests/audio/test_actor.py

@@ -231,6 +231,62 @@ class AudioEventTest(unittest.TestCase):
         call = mock.call('stream_changed', uri=None)
         self.assertIn(call, send_mock.call_args_list)
 
+    def test_position_changed_on_pause(self, send_mock):
+        self.audio.prepare_change()
+        self.audio.set_uri(self.song_uri)
+        self.audio.pause_playback()
+        self.audio.wait_for_state_change()
+
+        self.audio.wait_for_state_change().get()
+
+        call = mock.call('position_changed', position=0)
+        self.assertIn(call, send_mock.call_args_list)
+
+    def test_position_changed_on_play(self, send_mock):
+        self.audio.prepare_change()
+        self.audio.set_uri(self.song_uri)
+        self.audio.start_playback()
+        self.audio.wait_for_state_change()
+
+        self.audio.wait_for_state_change().get()
+
+        call = mock.call('position_changed', position=0)
+        self.assertIn(call, send_mock.call_args_list)
+
+    def test_position_changed_on_seek(self, send_mock):
+        self.audio.prepare_change()
+        self.audio.set_uri(self.song_uri)
+        self.audio.set_position(2000)
+
+        self.audio.wait_for_state_change().get()
+
+        call = mock.call('position_changed', position=0)
+        self.assertNotIn(call, send_mock.call_args_list)
+
+    def test_position_changed_on_seek_after_play(self, send_mock):
+        self.audio.prepare_change()
+        self.audio.set_uri(self.song_uri)
+        self.audio.start_playback()
+        self.audio.wait_for_state_change()
+        self.audio.set_position(2000)
+
+        self.audio.wait_for_state_change().get()
+
+        call = mock.call('position_changed', position=2000)
+        self.assertIn(call, send_mock.call_args_list)
+
+    def test_position_changed_on_seek_after_pause(self, send_mock):
+        self.audio.prepare_change()
+        self.audio.set_uri(self.song_uri)
+        self.audio.pause_playback()
+        self.audio.wait_for_state_change()
+        self.audio.set_position(2000)
+
+        self.audio.wait_for_state_change().get()
+
+        call = mock.call('position_changed', position=2000)
+        self.assertIn(call, send_mock.call_args_list)
+
     # Unlike the other events, having the state changed done is not
     # enough to ensure our event is called. So we setup a threading
     # event that we can wait for with a timeout while the track playback

tests/audio/test_listener.py

@@ -27,3 +27,6 @@ class AudioListenerTest(unittest.TestCase):
 
     def test_listener_has_default_impl_for_stream_changed(self):
         self.listener.stream_changed(None)
+
+    def test_listener_has_default_impl_for_position_changed(self):
+        self.listener.position_changed(None)