[gnome-photos] Let the back button cancel ongoing loads

[Debarshi Ray <debarshir src gnome org>]

commit 9679faa06af0c28d34ef6ee682effb3316a25691
Author: Debarshi Ray <debarshir gnome org>
Date:   Fri Sep 26 15:03:20 2014 +0200

    Let the back button cancel ongoing loads
    
    Original patch from Pranav Kant for gnome-documents.
    
    Fixes: https://bugzilla.gnome.org/734845

 src/photos-embed.c        |    5 ++++-
 src/photos-item-manager.c |    9 +++++----
 src/photos-item-manager.h |    2 +-
 src/photos-main-toolbar.c |   22 ++++++++++++++++++++++
 src/photos-main-toolbar.h |    3 +++
 5 files changed, 35 insertions(+), 6 deletions(-)
---
diff --git a/src/photos-embed.c b/src/photos-embed.c
index 5bd9714..14f886c 100644
--- a/src/photos-embed.c
+++ b/src/photos-embed.c
@@ -216,6 +216,7 @@ photos_embed_load_finished (PhotosEmbed *self, PhotosBaseItem *item, GeglNode *n
 {
   PhotosEmbedPrivate *priv = self->priv;
 
+  photos_main_toolbar_set_cancellable (PHOTOS_MAIN_TOOLBAR (priv->toolbar), NULL);
   photos_embed_clear_load_timer (self);
   photos_spinner_box_stop (PHOTOS_SPINNER_BOX (priv->spinner_box));
 
@@ -242,7 +243,7 @@ photos_embed_load_show_timeout (gpointer user_data)
 
 
 static void
-photos_embed_load_started (PhotosEmbed *self)
+photos_embed_load_started (PhotosEmbed *self, PhotosBaseItem *item, GCancellable *cancellable)
 {
   PhotosEmbedPrivate *priv = self->priv;
   PhotosWindowMode mode;
@@ -271,6 +272,8 @@ photos_embed_load_started (PhotosEmbed *self)
   photos_mode_controller_set_window_mode (priv->mode_cntrlr, PHOTOS_WINDOW_MODE_PREVIEW);
   photos_mode_controller_set_can_fullscreen (priv->mode_cntrlr, TRUE);
 
+  photos_main_toolbar_set_cancellable (PHOTOS_MAIN_TOOLBAR (priv->toolbar), cancellable);
+
   photos_embed_clear_load_timer (self);
   self->priv->load_show_id = g_timeout_add (400, photos_embed_load_show_timeout, g_object_ref (self));
 }
diff --git a/src/photos-item-manager.c b/src/photos-item-manager.c
index a8f330e..62e0443 100644
--- a/src/photos-item-manager.c
+++ b/src/photos-item-manager.c
@@ -326,7 +326,7 @@ photos_item_manager_set_active_object (PhotosBaseManager *manager, GObject *obje
                                    photos_item_manager_item_load,
                                    g_object_ref (self));
 
-      g_signal_emit (self, signals[LOAD_STARTED], 0, PHOTOS_BASE_ITEM (object));
+      g_signal_emit (self, signals[LOAD_STARTED], 0, PHOTOS_BASE_ITEM (object), priv->loader_cancellable);
     }
 
  out:
@@ -421,10 +421,11 @@ photos_item_manager_class_init (PhotosItemManagerClass *class)
                                                          load_started),
                                         NULL, /*accumulator */
                                         NULL, /*accu_data */
-                                        g_cclosure_marshal_VOID__OBJECT,
+                                        g_cclosure_marshal_generic,
                                         G_TYPE_NONE,
-                                        1,
-                                        PHOTOS_TYPE_BASE_ITEM);
+                                        2,
+                                        PHOTOS_TYPE_BASE_ITEM,
+                                        G_TYPE_CANCELLABLE);
 }
 
 
diff --git a/src/photos-item-manager.h b/src/photos-item-manager.h
index 43f6155..e246395 100644
--- a/src/photos-item-manager.h
+++ b/src/photos-item-manager.h
@@ -73,7 +73,7 @@ struct _PhotosItemManagerClass
   /* signals */
   void (*active_collection_changed) (PhotosItemManager *self, PhotosBaseItem *collection);
   void (*load_finished)             (PhotosItemManager *self, PhotosBaseItem *item, GeglNode *node);
-  void (*load_started)              (PhotosItemManager *self, PhotosBaseItem *item);
+  void (*load_started)              (PhotosItemManager *self, PhotosBaseItem *item, GCancellable 
*cancellable);
 };
 
 GType                     photos_item_manager_get_type           (void) G_GNUC_CONST;
diff --git a/src/photos-main-toolbar.c b/src/photos-main-toolbar.c
index edbbd5e..4180388 100644
--- a/src/photos-main-toolbar.c
+++ b/src/photos-main-toolbar.c
@@ -46,6 +46,7 @@
 struct _PhotosMainToolbarPrivate
 {
   GAction *search;
+  GCancellable *loader_cancellable;
   GSimpleAction *gear_menu;
   GtkWidget *coll_back_button;
   GtkWidget *favorite_button;
@@ -322,6 +323,9 @@ photos_main_toolbar_back_button_clicked (PhotosMainToolbar *self)
 {
   PhotosMainToolbarPrivate *priv = self->priv;
 
+  if (priv->loader_cancellable != NULL)
+    g_cancellable_cancel (priv->loader_cancellable);
+
   photos_base_manager_set_active_object (priv->item_mngr, NULL);
   photos_mode_controller_go_back (priv->mode_cntrlr);
 }
@@ -687,6 +691,7 @@ photos_main_toolbar_dispose (GObject *object)
 
   photos_main_toolbar_clear_state_data (self);
 
+  g_clear_object (&priv->loader_cancellable);
   g_clear_object (&priv->searchbar);
   g_clear_object (&priv->item_mngr);
   g_clear_object (&priv->mode_cntrlr);
@@ -885,6 +890,23 @@ photos_main_toolbar_reset_toolbar_mode (PhotosMainToolbar *self)
 
 
 void
+photos_main_toolbar_set_cancellable (PhotosMainToolbar *self, GCancellable *cancellable)
+{
+  PhotosMainToolbarPrivate *priv = self->priv;
+
+  if (cancellable == priv->loader_cancellable)
+    return;
+
+  g_clear_object (&priv->loader_cancellable);
+
+  if (cancellable != NULL)
+    g_object_ref (cancellable);
+
+  priv->loader_cancellable = cancellable;
+}
+
+
+void
 photos_main_toolbar_set_stack (PhotosMainToolbar *self, GtkStack *stack)
 {
   photos_header_bar_set_stack (PHOTOS_HEADER_BAR (self->priv->toolbar), stack);
diff --git a/src/photos-main-toolbar.h b/src/photos-main-toolbar.h
index 4e8f9b6..3ad4814 100644
--- a/src/photos-main-toolbar.h
+++ b/src/photos-main-toolbar.h
@@ -81,6 +81,9 @@ gboolean               photos_main_toolbar_is_focus               (PhotosMainToo
 
 void                   photos_main_toolbar_reset_toolbar_mode     (PhotosMainToolbar *self);
 
+void                   photos_main_toolbar_set_cancellable        (PhotosMainToolbar *self,
+                                                                   GCancellable *cancellable);
+
 void                   photos_main_toolbar_set_stack              (PhotosMainToolbar *self, GtkStack *stack);
 
 void                   photos_main_toolbar_set_view_model         (PhotosMainToolbar *self, PhotosViewModel 
*model);