[pitivi] keyframe: handle comparison with None more gracefully, interpolator: use setObjectTime on start/end

[Edward Hervey <edwardrv src gnome org>]

commit 6a265cdb8cbd9ea3fb840085d329ef045ddd164f
Author: Brandon Lewis <brandon_lewis berkeley edu>
Date:   Fri May 29 16:39:35 2009 -0700

    keyframe: handle comparison with None more gracefully, interpolator: use setObjectTime on start/end keyframes

 pitivi/timeline/track.py |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)
---
diff --git a/pitivi/timeline/track.py b/pitivi/timeline/track.py
index 13b27e2..911d0f7 100644
--- a/pitivi/timeline/track.py
+++ b/pitivi/timeline/track.py
@@ -99,13 +99,17 @@ class Keyframe(Signallable):
     value = property(getValue, setValue)
 
     def __cmp__(self, other):
-        return cmp(self.time, other.time)
+        if other:
+            return cmp(self.time, other.time)
+        return self
 
 class FixedKeyframe(Keyframe):
 
     def setTime(self, time):
         pass
 
+    time = property(Keyframe.getTime, setTime)
+
 class Interpolator(Signallable):
 
     """The bridge between the gstreamer dynamic property API and pitivi track
@@ -144,9 +148,9 @@ class Interpolator(Signallable):
         self.start = FixedKeyframe(self)
         self.end = FixedKeyframe(self)
         self.start.value = self._default
-        self.start.time = 0
+        self.start.setObjectTime(0)
         self.end.value = self._default
-        self.end.time = trackobject.factory.duration
+        self.end.setObjectTime(trackobject.factory.duration)
 
         data = [(self.start.time, self.start.value), (self.end.time,
             self.end.value)]