[gnome-photos: 2/5] item-manager: Sort the child BaseManagers in decreasing order of mtime

[Debarshi Ray <debarshir src gnome org>]

commit 80bfb4b271e11cacbe23fa716bc6a69d797bec55
Author: Debarshi Ray <debarshir gnome org>
Date:   Wed Dec 7 12:55:08 2016 +0100

    item-manager: Sort the child BaseManagers in decreasing order of mtime
    
    We cannot use an unsorted child BaseManager to navigate while
    previewing because the order won't match the one in the overview grid.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=775754

 src/photos-item-manager.c |   25 ++++++++++++++++++++++++-
 1 files changed, 24 insertions(+), 1 deletions(-)
---
diff --git a/src/photos-item-manager.c b/src/photos-item-manager.c
index ba411fe..dd8e9d9 100644
--- a/src/photos-item-manager.c
+++ b/src/photos-item-manager.c
@@ -609,6 +609,29 @@ photos_item_manager_set_active_object (PhotosBaseManager *manager, GObject *obje
 }
 
 
+static gint
+photos_item_manager_sort_func (gconstpointer a, gconstpointer b, gpointer user_data)
+{
+  PhotosBaseItem *item_a = PHOTOS_BASE_ITEM ((gpointer) a);
+  PhotosBaseItem *item_b = PHOTOS_BASE_ITEM ((gpointer) b);
+  gint ret_val;
+  gint64 mtime_a;
+  gint64 mtime_b;
+
+  mtime_a = photos_base_item_get_mtime (item_a);
+  mtime_b = photos_base_item_get_mtime (item_b);
+
+  if (mtime_a > mtime_b)
+    ret_val = -1;
+  else if (mtime_a == mtime_b)
+    ret_val = 0;
+  else
+    ret_val = 1;
+
+  return ret_val;
+}
+
+
 static void
 photos_item_manager_dispose (GObject *object)
 {
@@ -681,7 +704,7 @@ photos_item_manager_init (PhotosItemManager *self)
   self->item_mngr_chldrn = (PhotosBaseManager **) g_malloc0_n (window_mode_class->n_values + 1,
                                                                sizeof (PhotosBaseManager *));
   for (i = 0; i < window_mode_class->n_values; i++)
-    self->item_mngr_chldrn[i] = photos_base_manager_new (NULL, NULL);
+    self->item_mngr_chldrn[i] = photos_base_manager_new (photos_item_manager_sort_func, NULL);
 
   g_signal_connect_swapped (self->item_mngr_chldrn[0],
                             "items-changed",