[gnome-photos] offset-controller: Cancel cursor_next_async during destruction

[Debarshi Ray <debarshir src gnome org>]

commit ef5f58d59f324cab1cc6b5daa68f4255e2957607
Author: Rafael Fonseca <r4f4rfs gmail com>
Date:   Mon Mar 21 16:16:29 2016 +0100

    offset-controller: Cancel cursor_next_async during destruction
    
    https://bugzilla.gnome.org/show_bug.cgi?id=763908

 src/photos-offset-controller.c |   24 +++++++++++++++++++-----
 1 files changed, 19 insertions(+), 5 deletions(-)
---
diff --git a/src/photos-offset-controller.c b/src/photos-offset-controller.c
index 0d4b005..3a15237 100644
--- a/src/photos-offset-controller.c
+++ b/src/photos-offset-controller.c
@@ -35,6 +35,7 @@
 
 struct _PhotosOffsetControllerPrivate
 {
+  GCancellable *cancellable;
   PhotosTrackerQueue *queue;
   gint count;
   gint offset;
@@ -62,8 +63,8 @@ enum
 static void
 photos_offset_controller_cursor_next (GObject *source_object, GAsyncResult *res, gpointer user_data)
 {
-  PhotosOffsetController *self = PHOTOS_OFFSET_CONTROLLER (user_data);
-  PhotosOffsetControllerPrivate *priv = self->priv;
+  PhotosOffsetController *self;
+  PhotosOffsetControllerPrivate *priv;
   GError *error;
   TrackerSparqlCursor *cursor = TRACKER_SPARQL_CURSOR (source_object);
   gboolean success;
@@ -75,11 +76,15 @@ photos_offset_controller_cursor_next (GObject *source_object, GAsyncResult *res,
   success = tracker_sparql_cursor_next_finish (cursor, res, &error);
   if (error != NULL)
     {
-      g_warning ("Unable to query the item count: %s", error->message);
+      if (!g_error_matches (error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
+        g_warning ("Unable to query the item count: %s", error->message);
       g_error_free (error);
       goto out;
     }
 
+  self = PHOTOS_OFFSET_CONTROLLER (user_data);
+  priv = self->priv;
+
   if (success)
     {
       priv->count = (gint) tracker_sparql_cursor_get_integer (cursor, 0);
@@ -88,7 +93,6 @@ photos_offset_controller_cursor_next (GObject *source_object, GAsyncResult *res,
 
  out:
   tracker_sparql_cursor_close (cursor);
-  g_object_unref (self);
 }
 
 
@@ -108,7 +112,10 @@ photos_offset_controller_reset_count_query_executed (GObject *source_object, GAs
       return;
     }
 
-  tracker_sparql_cursor_next_async (cursor, NULL, photos_offset_controller_cursor_next, g_object_ref (self));
+  tracker_sparql_cursor_next_async (cursor,
+                                    self->priv->cancellable,
+                                    photos_offset_controller_cursor_next,
+                                    self);
   g_object_unref (cursor);
 }
 
@@ -118,6 +125,12 @@ photos_offset_controller_dispose (GObject *object)
 {
   PhotosOffsetController *self = PHOTOS_OFFSET_CONTROLLER (object);
 
+  if (self->priv->cancellable != NULL)
+    {
+      g_cancellable_cancel (self->priv->cancellable);
+      g_clear_object (&self->priv->cancellable);
+    }
+
   g_clear_object (&self->priv->queue);
 
   G_OBJECT_CLASS (photos_offset_controller_parent_class)->dispose (object);
@@ -132,6 +145,7 @@ photos_offset_controller_init (PhotosOffsetController *self)
   self->priv = photos_offset_controller_get_instance_private (self);
   priv = self->priv;
 
+  priv->cancellable = g_cancellable_new ();
   priv->queue = photos_tracker_queue_dup_singleton (NULL, NULL);
 }