[gnome-music/wip/jfelder/gstplayer-state-test: 2/3] gstplayer: Filter duplicate state changes

[Jean Felder <jfelder src gnome org>]

commit 52497d60c9ddb3679f8c51248b9c1cc67e7aeb5e
Author: Jean Felder <jfelder src gnome org>
Date:   Mon Oct 15 22:03:17 2018 +0200

    gstplayer: Filter duplicate state changes
    
    GStreamer pipeline is really verbose. It can lead to a lot of
    duplications: a state change property is notified even if the value
    has not changed.
    Check for the previous state to filter the duplicate state changes.

 gnomemusic/gstplayer.py | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)
---
diff --git a/gnomemusic/gstplayer.py b/gnomemusic/gstplayer.py
index bd52f557..e14af354 100644
--- a/gnomemusic/gstplayer.py
+++ b/gnomemusic/gstplayer.py
@@ -89,6 +89,7 @@ class GstPlayer(GObject.GObject):
             'message::duration-changed', self._on_duration_changed)
         self._bus.connect('message::new-clock', self._on_new_clock)
 
+        self._previous_state = Playback.STOPPED
         self.state = Playback.STOPPED
 
     @log
@@ -149,8 +150,15 @@ class GstPlayer(GObject.GObject):
 
         # Setting self.state triggers the property signal, which is
         # used down the line.
-        print("gstplayer - bus_state_changed", self.state)
-        self.state = self.state
+        current_state = self.props.state
+        if current_state == self._previous_state:
+            return
+
+        print(
+            "gstplayer - bus_state_changed", self.state, "previous state:",
+            self._previous_state)
+        self._previous_state = current_state
+        self.notify('state')
 
     @log
     def _on_duration_changed(self, bus, message):