[gnome-photos/gnome-3-16] Let users page through search results in the preview

[Debarshi Ray <debarshir src gnome org>]

commit b8459ca3b9d2778f3a88cbbcbdce36e759bf99ac
Author: Debarshi Ray <debarshir gnome org>
Date:   Wed Oct 7 19:33:57 2015 +0200

    Let users page through search results in the preview
    
    We were losing the search results when turning off the searchbar before
    moving to the preview. We avoid this by freezing the TrackerControllers
    so that they don't react to any changes in the search parameters.
    
    The TrackerControllers are thawed *after* we are back and the search
    state has been restored to avoid needless queries.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=741593

 src/photos-embed.c              |   49 +++++++++++++++++++++++++++++++++++++-
 src/photos-tracker-controller.c |   11 ++++++++
 src/photos-tracker-controller.h |    5 +++-
 3 files changed, 62 insertions(+), 3 deletions(-)
---
diff --git a/src/photos-embed.c b/src/photos-embed.c
index bce2568..141a3b5 100644
--- a/src/photos-embed.c
+++ b/src/photos-embed.c
@@ -45,7 +45,9 @@
 #include "photos-search-type-manager.h"
 #include "photos-source.h"
 #include "photos-source-manager.h"
+#include "photos-tracker-controller.h"
 #include "photos-tracker-overview-controller.h"
+#include "photos-utils.h"
 #include "photos-view-container.h"
 #include "photos-view-model.h"
 
@@ -63,6 +65,7 @@ struct _PhotosEmbedSearchState
 struct _PhotosEmbedPrivate
 {
   GAction *search_action;
+  GIOExtensionPoint *extension_point;
   GtkWidget *collections;
   GtkWidget *favorites;
   GtkWidget *no_results;
@@ -315,6 +318,32 @@ photos_embed_save_search (PhotosEmbed *self)
 
 
 static void
+photos_embed_tracker_controllers_set_frozen (PhotosEmbed *self, gboolean frozen)
+{
+  GList *extensions;
+  GList *l;
+
+  extensions = g_io_extension_point_get_extensions (self->priv->extension_point);
+  for (l = extensions; l != NULL; l = l->next)
+    {
+      GIOExtension *extension = (GIOExtension *) l->data;
+      GType type;
+      PhotosTrackerController *trk_cntrlr;
+
+      type = g_io_extension_get_type (extension);
+
+      /* Strictly speaking, we need to set the "mode" too, but that
+       * is a bit inconvenient, so we operate under the assumption
+       * that the objects have already been constructed.
+       */
+      trk_cntrlr = PHOTOS_TRACKER_CONTROLLER (g_object_new (type, NULL));
+      photos_tracker_controller_set_frozen (trk_cntrlr, frozen);
+      g_object_unref (trk_cntrlr);
+    }
+}
+
+
+static void
 photos_embed_active_changed (PhotosBaseManager *manager, GObject *object, gpointer user_data)
 {
   PhotosEmbed *self = PHOTOS_EMBED (user_data);
@@ -325,12 +354,22 @@ photos_embed_active_changed (PhotosBaseManager *manager, GObject *object, gpoint
   GVariant *state;
   gboolean show_search;
 
+  active_collection = photos_item_manager_get_active_collection (PHOTOS_ITEM_MANAGER (priv->item_mngr));
+  active_item = photos_base_manager_get_active_object (priv->item_mngr);
+
+  /* We want to freeze before saving the search state and to thaw
+   * after restoring it. We could thaw it earlier too, but that would
+   * lead to a bunch of needless queries from the TrackerControllers.
+   *
+   * Note that we don't want to freeze when showing a collection.
+   */
+  if (active_item != (GObject *) active_collection) /* active_item != NULL */
+    photos_embed_tracker_controllers_set_frozen (self, TRUE);
+
   /* Hide the search bar when we are moving from the search to the
    * preview or collection viewin. Restore it when we are back.
    */
 
-  active_collection = photos_item_manager_get_active_collection (PHOTOS_ITEM_MANAGER (priv->item_mngr));
-  active_item = photos_base_manager_get_active_object (priv->item_mngr);
   mode = photos_mode_controller_get_window_mode (priv->mode_cntrlr);
   show_search = (mode == PHOTOS_WINDOW_MODE_PREVIEW && active_item == NULL && active_collection == NULL)
                 || (mode == PHOTOS_WINDOW_MODE_SEARCH && active_item == NULL);
@@ -342,6 +381,10 @@ photos_embed_active_changed (PhotosBaseManager *manager, GObject *object, gpoint
 
   state = g_variant_new ("b", show_search);
   g_action_change_state (priv->search_action, state);
+
+  /* See above. */
+  if (active_item == (GObject *) active_collection) /* active_item == NULL */
+    photos_embed_tracker_controllers_set_frozen (self, FALSE);
 }
 
 
@@ -593,6 +636,8 @@ photos_embed_init (PhotosEmbed *self)
   gtk_orientable_set_orientation (GTK_ORIENTABLE (self), GTK_ORIENTATION_VERTICAL);
   gtk_widget_show (GTK_WIDGET (self));
 
+  priv->extension_point = g_io_extension_point_lookup (PHOTOS_TRACKER_CONTROLLER_EXTENSION_POINT_NAME);
+
   priv->selection_toolbar = photos_selection_toolbar_new ();
   gtk_box_pack_end (GTK_BOX (self), priv->selection_toolbar, FALSE, FALSE, 0);
 
diff --git a/src/photos-tracker-controller.c b/src/photos-tracker-controller.c
index a47b59b..7519bac 100644
--- a/src/photos-tracker-controller.c
+++ b/src/photos-tracker-controller.c
@@ -54,6 +54,7 @@ struct _PhotosTrackerControllerPrivate
   PhotosQuery *current_query;
   PhotosTrackerQueue *queue;
   PhotosWindowMode mode;
+  gboolean is_frozen;
   gboolean is_started;
   gboolean query_queued;
   gboolean querying;
@@ -243,6 +244,9 @@ photos_tracker_controller_refresh_internal (PhotosTrackerController *self, gint
 
   priv->is_started = TRUE;
 
+  if (priv->is_frozen)
+    return;
+
   if (flags & PHOTOS_TRACKER_REFRESH_FLAGS_RESET_OFFSET)
     photos_offset_controller_reset_offset (priv->offset_cntrlr);
 
@@ -460,6 +464,13 @@ photos_tracker_controller_refresh_for_object (PhotosTrackerController *self)
 
 
 void
+photos_tracker_controller_set_frozen (PhotosTrackerController *self, gboolean frozen)
+{
+  self->priv->is_frozen = frozen;
+}
+
+
+void
 photos_tracker_controller_start (PhotosTrackerController *self)
 {
   PhotosTrackerControllerPrivate *priv = self->priv;
diff --git a/src/photos-tracker-controller.h b/src/photos-tracker-controller.h
index e2dfac2..9661975 100644
--- a/src/photos-tracker-controller.h
+++ b/src/photos-tracker-controller.h
@@ -1,6 +1,6 @@
 /*
  * Photos - access, organize and share your photos on GNOME
- * Copyright © 2012, 2014 Red Hat, Inc.
+ * Copyright © 2012, 2014, 2015 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
@@ -79,6 +79,9 @@ struct _PhotosTrackerControllerClass
 
 GType                     photos_tracker_controller_get_type          (void) G_GNUC_CONST;
 
+void                      photos_tracker_controller_set_frozen        (PhotosTrackerController *self,
+                                                                       gboolean frozen);
+
 gboolean                  photos_tracker_controller_get_query_status  (PhotosTrackerController *self);
 
 void                      photos_tracker_controller_refresh_for_object (PhotosTrackerController *self);