[pitivi] viewer: Get rid of the ambiguous _tmp_pipeline field

[Mathieu Duponchelle <mathieudu src gnome org>]

commit fcecb091795ddcc9fd033fb93b7329b8b9f12a19
Author: Alexandru Băluț <alexandru balut gmail com>
Date:   Mon Jan 13 16:21:37 2014 +0100

    viewer: Get rid of the ambiguous _tmp_pipeline field

 pitivi/utils/pipeline.py |   15 ++++++++++++++-
 pitivi/viewer.py         |   27 ++++++++++++---------------
 2 files changed, 26 insertions(+), 16 deletions(-)
---
diff --git a/pitivi/utils/pipeline.py b/pitivi/utils/pipeline.py
index 4e1d1f0..0b035ef 100644
--- a/pitivi/utils/pipeline.py
+++ b/pitivi/utils/pipeline.py
@@ -489,12 +489,25 @@ class SimplePipeline(Signallable, Loggable):
         try:
             res, dur = self._pipeline.query_duration(format)
         except Exception, e:
-
             self.handleException(e)
             raise PipelineError("Couldn't get duration: %s" % e)
 
         if not res:
             raise PipelineError("Couldn't get duration: Returned None")
+        return dur
+
+
+class AssetPipeline(SimplePipeline):
+    """
+    Pipeline for playing a single clip.
+    """
+
+    def __init__(self, clip):
+        bPipeline = Gst.ElementFactory.make("playbin", None)
+        bPipeline.set_property("uri", clip.props.uri)
+        SimplePipeline.__init__(self, bPipeline, bPipeline)
+
+        self.clip = clip
 
 
 class Pipeline(GES.Pipeline, SimplePipeline):
diff --git a/pitivi/viewer.py b/pitivi/viewer.py
index d4412b3..5f6096b 100644
--- a/pitivi/viewer.py
+++ b/pitivi/viewer.py
@@ -36,11 +36,11 @@ from time import time
 from math import pi
 
 from pitivi.settings import GlobalSettings
-from pitivi.utils.pipeline import Seeker, SimplePipeline
-from pitivi.utils.ui import SPACING, hex_to_rgb
-from pitivi.utils.widgets import TimeWidget
 from pitivi.utils.loggable import Loggable
 from pitivi.utils.misc import format_ns
+from pitivi.utils.pipeline import AssetPipeline, Seeker
+from pitivi.utils.ui import SPACING, hex_to_rgb
+from pitivi.utils.widgets import TimeWidget
 
 GlobalSettings.addConfigSection("viewer")
 GlobalSettings.addConfigOption("viewerDocked", section="viewer",
@@ -92,8 +92,6 @@ class ViewerContainer(Gtk.VBox, Loggable):
         self.log("New ViewerContainer")
 
         self.pipeline = None
-        self._tmp_pipeline = None  # Used for displaying a preview when trimming
-
         self.sink = None
         self.docked = True
 
@@ -441,29 +439,28 @@ class ViewerContainer(Gtk.VBox, Loggable):
 
         clip_uri = tl_obj.props.uri
         cur_time = time()
-        if not self._tmp_pipeline:
+        if self.pipeline == self.app.current_project.pipeline:
             self.debug("Creating temporary pipeline for clip %s, position %s",
                 clip_uri, format_ns(position))
-
             self._oldTimelinePos = self.pipeline.getPosition()
-            self._tmp_pipeline = Gst.ElementFactory.make("playbin", None)
-            self._tmp_pipeline.set_property("uri", clip_uri)
-            self.setPipeline(SimplePipeline(self._tmp_pipeline, self._tmp_pipeline))
+            self.setPipeline(AssetPipeline(tl_obj))
             self._lastClipTrimTime = cur_time
+
         if (cur_time - self._lastClipTrimTime) > 0.2 and self.pipeline.getState() == Gst.State.PAUSED:
             # Do not seek more than once every 200 ms (for performance)
-            self._tmp_pipeline.seek_simple(Gst.Format.TIME, Gst.SeekFlags.FLUSH, position)
+            self.pipeline.simple_seek(position)
             self._lastClipTrimTime = cur_time
 
     def clipTrimPreviewFinished(self):
         """
         After trimming a clip, reset the project pipeline into the viewer.
         """
-        if self._tmp_pipeline is not None:
-            self._tmp_pipeline.set_state(Gst.State.NULL)
-            self._tmp_pipeline = None  # Free the memory
+        if self.pipeline is not self.app.current_project.pipeline:
+            self.pipeline.setState(Gst.State.NULL)
+            # Using pipeline.getPosition() here does not work because for some
+            # reason it's a bit off, that's why we need self._oldTimelinePos.
             self.setPipeline(self.app.current_project.pipeline, self._oldTimelinePos)
-            self.debug("Back to old pipeline")
+            self.debug("Back to the project's pipeline")
 
     def _pipelineStateChangedCb(self, unused_pipeline, state):
         """