[gnome-music/wip/mschraal/player-factor-out-gstreamer] gstplayer: Be more reliable about duration

[Marinus Schraal <mschraal src gnome org>]

commit 99977225530d1704e6c40945d7505f09c1f9eebb
Author: Marinus Schraal <mschraal gnome org>
Date:   Sat Feb 17 20:44:10 2018 +0100

    gstplayer: Be more reliable about duration

 gnomemusic/gstplayer.py | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)
---
diff --git a/gnomemusic/gstplayer.py b/gnomemusic/gstplayer.py
index 55a3cf9..e38ec82 100644
--- a/gnomemusic/gstplayer.py
+++ b/gnomemusic/gstplayer.py
@@ -227,10 +227,17 @@ class GstPlayer(GObject.GObject):
     @log
     def duration(self):
         """Total duration in seconds (float)"""
-        if self._duration == None:
-            self._duration = self._player.query_duration(
-                Gst.Format.TIME)[1] / 10**9
-        print("duration ", self._duration)
+        if self.state == Playback.STOPPED:
+            return None
+
+        success, duration = self._player.query_duration(
+            Gst.Format.TIME)
+
+        if success:
+            self._duration = duration / 10**9
+        else:
+            self._duration = None
+
         return self._duration
 
     @GObject.Property