[gnome-photos] Move the code to update the OffsetControllers' count

[Debarshi Ray <debarshir src gnome org>]

commit 418a1e1069e6b65618f0c7cb7956ee83ac3c6451
Author: Debarshi Ray <debarshir gnome org>
Date:   Wed Jan 11 10:26:37 2017 +0100

    Move the code to update the OffsetControllers' count
    
    Once we port to GtkFlowBox, we will lose the ViewModel class.
    Therefore, we need to find a new home for the code that resets the
    OffsetControllers' count whenever BaseItems are added or removed to
    the child BaseManagers inside ItemManager.
    
    TrackerController is a good choice because it already uses ItemManager
    and the mode-specific OffsetController.
    
    The other option was to do it in ItemManager itself, but since some
    OffsetControllers also use ItemManager it will create problems when the
    singletons are initially created.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=690623

 src/photos-tracker-controller.c |   62 ++++++++++++++++++++++++++++++++++++++-
 src/photos-view-model.c         |   44 ---------------------------
 2 files changed, 61 insertions(+), 45 deletions(-)
---
diff --git a/src/photos-tracker-controller.c b/src/photos-tracker-controller.c
index 5ddd6ad..2ead21e 100644
--- a/src/photos-tracker-controller.c
+++ b/src/photos-tracker-controller.c
@@ -1,6 +1,6 @@
 /*
  * Photos - access, organize and share your photos on GNOME
- * Copyright © 2012 – 2016 Red Hat, Inc.
+ * Copyright © 2012 – 2017 Red Hat, Inc.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -61,6 +61,7 @@ struct _PhotosTrackerControllerPrivate
   gboolean refresh_pending;
   gint query_queued_flags;
   gint64 last_query_time;
+  guint reset_count_id;
 };
 
 enum
@@ -86,6 +87,11 @@ EGG_DEFINE_COUNTER (instances,
                     "Number of PhotosTrackerController instances")
 
 
+enum
+{
+  RESET_COUNT_TIMEOUT = 500 /* ms */
+};
+
 typedef enum
 {
   PHOTOS_TRACKER_REFRESH_FLAGS_NONE = 0,
@@ -97,6 +103,41 @@ static void photos_tracker_controller_refresh_internal (PhotosTrackerController
 static void photos_tracker_controller_set_query_status (PhotosTrackerController *self, gboolean 
query_status);
 
 
+static gboolean
+photos_tracker_controller_reset_count_timeout (gpointer user_data)
+{
+  PhotosTrackerController *self = PHOTOS_TRACKER_CONTROLLER (user_data);
+  PhotosTrackerControllerPrivate *priv;
+
+  priv = photos_tracker_controller_get_instance_private (self);
+
+  priv->reset_count_id = 0;
+  photos_offset_controller_reset_count (priv->offset_cntrlr);
+  return G_SOURCE_REMOVE;
+}
+
+
+static void
+photos_tracker_controller_item_added_removed (PhotosTrackerController *self)
+{
+  PhotosTrackerControllerPrivate *priv;
+
+  priv = photos_tracker_controller_get_instance_private (self);
+
+  /* Update the count so that PhotosOffsetController has the correct
+   * values. Otherwise things like loading more items and "No
+   * Results" page will not work correctly.
+   */
+
+  if (priv->reset_count_id == 0)
+    {
+      priv->reset_count_id = g_timeout_add (RESET_COUNT_TIMEOUT,
+                                            photos_tracker_controller_reset_count_timeout,
+                                            self);
+    }
+}
+
+
 static void
 photos_tracker_controller_query_error (PhotosTrackerController *self, GError *error)
 {
@@ -362,11 +403,24 @@ photos_tracker_controller_constructed (GObject *object)
 {
   PhotosTrackerController *self = PHOTOS_TRACKER_CONTROLLER (object);
   PhotosTrackerControllerPrivate *priv;
+  PhotosBaseManager *item_mngr_chld;
 
   priv = photos_tracker_controller_get_instance_private (self);
 
   G_OBJECT_CLASS (photos_tracker_controller_parent_class)->constructed (object);
 
+  item_mngr_chld = photos_item_manager_get_for_mode (PHOTOS_ITEM_MANAGER (priv->item_mngr), priv->mode);
+  g_signal_connect_object (item_mngr_chld,
+                           "object-added",
+                           G_CALLBACK (photos_tracker_controller_item_added_removed),
+                           self,
+                           G_CONNECT_SWAPPED);
+  g_signal_connect_object (item_mngr_chld,
+                           "object-removed",
+                           G_CALLBACK (photos_tracker_controller_item_added_removed),
+                           self,
+                           G_CONNECT_SWAPPED);
+
   priv->offset_cntrlr = PHOTOS_TRACKER_CONTROLLER_GET_CLASS (self)->get_offset_controller (self);
   g_signal_connect_swapped (priv->offset_cntrlr,
                             "offset-changed",
@@ -383,6 +437,12 @@ photos_tracker_controller_dispose (GObject *object)
 
   priv = photos_tracker_controller_get_instance_private (self);
 
+  if (priv->reset_count_id != 0)
+    {
+      g_source_remove (priv->reset_count_id);
+      priv->reset_count_id = 0;
+    }
+
   g_clear_object (&priv->src_mngr);
   g_clear_object (&priv->offset_cntrlr);
   g_clear_object (&priv->queue);
diff --git a/src/photos-view-model.c b/src/photos-view-model.c
index cca4a5c..6652e5d 100644
--- a/src/photos-view-model.c
+++ b/src/photos-view-model.c
@@ -50,7 +50,6 @@ struct _PhotosViewModel
   gchar *row_ref_key;
   gint n_rows;
   gint64 oldest_mtime;
-  guint reset_count_id;
 };
 
 enum
@@ -63,12 +62,6 @@ enum
 G_DEFINE_TYPE (PhotosViewModel, photos_view_model, GTK_TYPE_LIST_STORE);
 
 
-enum
-{
-  RESET_COUNT_TIMEOUT = 500 /* ms */
-};
-
-
 static void
 photos_view_model_info_set (PhotosViewModel *self, PhotosBaseItem *item, GtkTreeIter *iter)
 {
@@ -84,25 +77,6 @@ photos_view_model_info_set (PhotosViewModel *self, PhotosBaseItem *item, GtkTree
 }
 
 
-static gboolean
-photos_view_model_reset_count_timeout (gpointer user_data)
-{
-  PhotosViewModel *self = PHOTOS_VIEW_MODEL (user_data);
-
-  self->reset_count_id = 0;
-  photos_offset_controller_reset_count (self->offset_cntrlr);
-  return G_SOURCE_REMOVE;
-}
-
-
-static void
-photos_view_model_reset_count (PhotosViewModel *self)
-{
-  if (self->reset_count_id == 0)
-    self->reset_count_id = g_timeout_add (RESET_COUNT_TIMEOUT, photos_view_model_reset_count_timeout, self);
-}
-
-
 static void
 photos_view_model_add_item (PhotosViewModel *self, PhotosBaseItem *item)
 {
@@ -113,12 +87,6 @@ photos_view_model_add_item (PhotosViewModel *self, PhotosBaseItem *item)
   gint step;
   gint64 mtime;
 
-  /* Update the count so that PhotosOffsetController has the correct
-   * values. Otherwise things like loading more items and "No
-   * Results" page will not work correctly.
-   */
-  photos_view_model_reset_count (self);
-
   offset = photos_offset_controller_get_offset (self->offset_cntrlr);
   step = photos_offset_controller_get_step (self->offset_cntrlr);
   mtime = photos_base_item_get_mtime (item);
@@ -207,12 +175,6 @@ photos_view_model_item_removed_foreach (GtkTreeModel *model,
 static void
 photos_view_model_remove_item (PhotosViewModel *self, PhotosBaseItem *item)
 {
-  /* Update the count so that PhotosOffsetController has the correct
-   * values. Otherwise things like loading more items and "No
-   * Results" page will not work correctly.
-   */
-  photos_view_model_reset_count (self);
-
   self->oldest_mtime = G_MAXINT64;
   gtk_tree_model_foreach (GTK_TREE_MODEL (self), photos_view_model_item_removed_foreach, item);
   g_object_set_data (G_OBJECT (item), self->row_ref_key, NULL);
@@ -320,12 +282,6 @@ photos_view_model_dispose (GObject *object)
 {
   PhotosViewModel *self = PHOTOS_VIEW_MODEL (object);
 
-  if (self->reset_count_id != 0)
-    {
-      g_source_remove (self->reset_count_id);
-      self->reset_count_id = 0;
-    }
-
   g_clear_object (&self->offset_cntrlr);
   g_clear_object (&self->trk_cntrlr);