[gnome-music/wip/jfelder/mpris-seek: 1/4] mpris: Do not send PlaybackStatus property if unchanged

[Jean Felder <jfelder src gnome org>]

commit d80ccc59bd670cd278374608ded409d59837f79b
Author: Jean Felder <jfelder src gnome org>
Date:   Tue Apr 16 11:55:57 2019 +0200

    mpris: Do not send PlaybackStatus property if unchanged
    
    GstPlayer state changes can be redundant because of its asynchronous
    nature. For example, when launching a new song, the playing state is
    sent two times. This results in the PlaybackStatus "Playing" property
    being sent two times.
    
    Checking that the status has really changed to avoid sending two times
    the same signal.
    
    Related: #43

 gnomemusic/mpris.py | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
---
diff --git a/gnomemusic/mpris.py b/gnomemusic/mpris.py
index d582208a..e064258f 100644
--- a/gnomemusic/mpris.py
+++ b/gnomemusic/mpris.py
@@ -240,6 +240,7 @@ class MediaPlayer2Service(Server):
         self._player_previous_type = None
         self._path_list = []
         self._metadata_list = []
+        self._previous_playback_status = "Stopped"
 
     @log
     def _get_playback_status(self):
@@ -468,9 +469,14 @@ class MediaPlayer2Service(Server):
 
     @log
     def _on_player_state_changed(self, klass, args):
+        playback_status = self._get_playback_status()
+        if playback_status == self._previous_playback_status:
+            return
+
+        self._previous_playback_status = playback_status
         self.PropertiesChanged(MediaPlayer2Service.MEDIA_PLAYER2_PLAYER_IFACE,
                                {
-                                   'PlaybackStatus': GLib.Variant('s', self._get_playback_status()),
+                                   'PlaybackStatus': GLib.Variant('s', playback_status),
                                },
                                [])