[js] pool for benshee player only if it is installed

fix mpris track change

src/music_track_listener.py

@@ -18,6 +18,7 @@
 ## You should have received a copy of the GNU General Public License
 ## along with Gajim.  If not, see <http://www.gnu.org/licenses/>.
 ##
+import os
 import gobject
 if __name__ == '__main__':
 	# install _() func before importing dbus_support
@@ -54,7 +55,7 @@ class MusicTrackListener(gobject.GObject):
 		## MPRIS
 		bus.add_signal_receiver(self._mpris_music_track_change_cb, 'TrackChange',
 			'org.freedesktop.MediaPlayer')
-		bus.add_signal_receiver(self._player_playing_changed_cb, 'StatusChange',
+		bus.add_signal_receiver(self._mpris_playing_changed_cb, 'StatusChange',
 			'org.freedesktop.MediaPlayer')
 			
 
@@ -77,6 +78,10 @@ class MusicTrackListener(gobject.GObject):
 			'playingSongPropertyChanged', 'org.gnome.Rhythmbox.Player')
 
 		## Banshee
+		# Banshee sucks because it only supports polling.
+		# Thus, we only register this is we are very sure that it's
+		# installed.
+		if os.name == 'posix' and os.system('which banshee >/dev/null 2>&1') == 0:
 			banshee_bus = dbus.SessionBus()
 			dubus = banshee_bus.get_object('org.freedesktop.DBus',
 				'/org/freedesktop/dbus')
@@ -131,6 +136,10 @@ class MusicTrackListener(gobject.GObject):
 		info.duration = int(song['length'])
 		return info
 
+	def _mpris_playing_changed_cb(self, playing):
+		if playing == 2:
+			self.emit('music-track-changed', None)
+
 	def _mpris_music_track_change_cb(self, arg):
 		info = self._mpris_properties_extract(arg)
 		self.emit('music-track-changed', info)