[pitivi] timeline: Avoid updating layers multiple times

[Thibault Saunier <tsaunier src gnome org>]

commit 819c13f223d7e76057c6987ca2cee197d5abbdcb
Author: Alexandru Băluț <alexandru balut gmail com>
Date:   Sun Feb 12 01:19:16 2017 +0100

    timeline: Avoid updating layers multiple times
    
    The layers are updated when their priorities are in good order, in
    __update_layers which is called also when the priority of a layer has
    been changed.
    
    Reviewed-by: Thibault Saunier <tsaunier gnome org>
    Differential Revision: https://phabricator.freedesktop.org/D1661

 pitivi/timeline/timeline.py     |   52 +++++++++++++++++---------------------
 tests/test_timeline_timeline.py |    8 +++---
 2 files changed, 27 insertions(+), 33 deletions(-)
---
diff --git a/pitivi/timeline/timeline.py b/pitivi/timeline/timeline.py
index 1011f17..1305d36 100644
--- a/pitivi/timeline/timeline.py
+++ b/pitivi/timeline/timeline.py
@@ -904,7 +904,7 @@ class Timeline(Gtk.EventBox, Zoomable, Loggable):
                                                  CommitTimelineFinalizingAction(pipeline)):
                     if self.__on_separators:
                         priority = self.separator_priority(self.__on_separators[1])
-                        created_layer = self.createLayer(priority)
+                        created_layer = self.create_layer(priority)
                     else:
                         created_layer = None
                     for layer, clip in self.__last_clips_on_leave:
@@ -1001,6 +1001,21 @@ class Timeline(Gtk.EventBox, Zoomable, Loggable):
         for ges_layer in self.ges_timeline.get_layers():
             self.__update_layer(ges_layer)
 
+    def __update_layer(self, ges_layer):
+        """Sets the position of the layer and its controls in their parent."""
+        position = ges_layer.props.priority * 2 + 1
+
+        # Update the position of the LayerControls and Layer widgets and
+        # also the position of the separators below them.
+        controls_separator, layers_separator = self._separators[ges_layer.props.priority + 1]
+        vbox = self.layout.layers_vbox
+        vbox.child_set_property(ges_layer.ui, "position", position)
+        vbox.child_set_property(layers_separator, "position", position + 1)
+
+        vbox = self._layers_controls_vbox
+        vbox.child_set_property(ges_layer.control_ui, "position", position)
+        vbox.child_set_property(controls_separator, "position", position + 1)
+
     def _remove_layer(self, ges_layer):
         self.info("Removing layer: %s", ges_layer.props.priority)
         self.layout.layers_vbox.remove(ges_layer.ui)
@@ -1192,49 +1207,28 @@ class Timeline(Gtk.EventBox, Zoomable, Loggable):
 
         self.editing_context.edit_to(position, self._on_layer)
 
-    def createLayer(self, priority):
+    def create_layer(self, priority):
         """Adds a new layer to the GES timeline."""
         self.debug("Creating layer: priority = %s", priority)
+        ges_layers = self.ges_timeline.get_layers()
+        assert 0 <= priority <= len(ges_layers)
         new_ges_layer = GES.Layer.new()
         new_ges_layer.props.priority = priority
         self.ges_timeline.add_layer(new_ges_layer)
 
-        ges_layers = self.ges_timeline.get_layers()
-        if priority < len(ges_layers):
-            for ges_layer in ges_layers:
-                if ges_layer == new_ges_layer:
-                    continue
-
-                if ges_layer.get_priority() >= priority:
-                    ges_layer.props.priority += 1
-                    self.__update_layer(ges_layer)
-
-        self.__update_layer(new_ges_layer)
+        for ges_layer in ges_layers:
+            if priority <= ges_layer.get_priority():
+                ges_layer.props.priority += 1
 
         return new_ges_layer
 
-    def __update_layer(self, ges_layer):
-        """Sets the position of the layer and its controls in their parent."""
-        position = ges_layer.props.priority * 2 + 1
-
-        # Update the position of the LayerControls and Layer widgets and
-        # also the position of the separators below them.
-        controls_separator, layers_separator = self._separators[ges_layer.props.priority + 1]
-        vbox = self.layout.layers_vbox
-        vbox.child_set_property(ges_layer.ui, "position", position)
-        vbox.child_set_property(layers_separator, "position", position + 1)
-
-        vbox = self._layers_controls_vbox
-        vbox.child_set_property(ges_layer.control_ui, "position", position)
-        vbox.child_set_property(controls_separator, "position", position + 1)
-
     def dragEnd(self):
         if self.editing_context:
             self._snapEndedCb()
 
             if self.__on_separators and self.__got_dragged and not self.__clickedHandle:
                 priority = self.separator_priority(self.__on_separators[1])
-                ges_layer = self.createLayer(priority)
+                ges_layer = self.create_layer(priority)
                 position = self.editing_context.new_position
                 self.editing_context.edit_to(position, ges_layer)
 
diff --git a/tests/test_timeline_timeline.py b/tests/test_timeline_timeline.py
index 886359f..a83a5f2 100644
--- a/tests/test_timeline_timeline.py
+++ b/tests/test_timeline_timeline.py
@@ -88,7 +88,7 @@ class TestLayers(BaseTestTimeline):
         # Allocate layers
         y = 0
         for priority, height in enumerate(heights):
-            ges_layer = timeline.createLayer(priority=priority)
+            ges_layer = timeline.create_layer(priority=priority)
             rect = Gdk.Rectangle()
             rect.y = y
             rect.height = height
@@ -159,7 +159,7 @@ class TestLayers(BaseTestTimeline):
         timeline = create_timeline_container().timeline
         ges_layers = []
         for priority in start_priorities:
-            ges_layer = timeline.createLayer(priority)
+            ges_layer = timeline.create_layer(priority)
             self.assertEqual(ges_layer.props.priority, priority)
             ges_layers.append(ges_layer)
         self.check_priorities_and_positions(timeline, ges_layers, expected_priorities)
@@ -218,7 +218,7 @@ class TestLayers(BaseTestTimeline):
         # Pitivi doesn't support removing the last remaining layer,
         # that's why we create an extra layer.
         for priority in range(len(removal_order) + 1):
-            ges_layer = timeline.createLayer(priority)
+            ges_layer = timeline.create_layer(priority)
             ges_layers.append(ges_layer)
 
         # Remove layers one by one in the specified order.
@@ -243,7 +243,7 @@ class TestLayers(BaseTestTimeline):
         # Add layers to move them later.
         ges_layers = []
         for priority in range(len(expected_priorities)):
-            ges_layer = timeline.createLayer(priority)
+            ges_layer = timeline.create_layer(priority)
             ges_layers.append(ges_layer)
 
         timeline.moveLayer(ges_layers[from_priority], to_priority)