[gnome-photos] Turn the PhotosBaseItem sub-classes into extensions

[Debarshi Ray <debarshir src gnome org>]

commit 8674918f1cf33553f10a9caef4964ab27b1eff45
Author: Debarshi Ray <debarshir gnome org>
Date:   Wed Jun 18 17:44:31 2014 +0200

    Turn the PhotosBaseItem sub-classes into extensions
    
    The idea is to reduce the amount of code that has to be sprinkled all
    over the place when adding a new content source. Instead, we should be
    able specify most of that in the sub-classes of PhotosBaseItem.
    
    This is the first step in that direction.
    
    Fixes: https://bugzilla.gnome.org/731865

 src/photos-application.c   |    3 +++
 src/photos-facebook-item.c |    8 +++++++-
 src/photos-flickr-item.c   |    8 +++++++-
 src/photos-local-item.c    |    9 +++++++--
 src/photos-utils.c         |   39 +++++++++++++++++++++++++++++++++++++++
 src/photos-utils.h         |    6 ++++++
 6 files changed, 69 insertions(+), 4 deletions(-)
---
diff --git a/src/photos-application.c b/src/photos-application.c
index 52e3218..22674c5 100644
--- a/src/photos-application.c
+++ b/src/photos-application.c
@@ -52,6 +52,7 @@
 #include "photos-single-item-job.h"
 #include "photos-source-manager.h"
 #include "photos-tracker-extract-priority.h"
+#include "photos-utils.h"
 
 
 struct _PhotosApplicationPrivate
@@ -938,6 +939,8 @@ photos_application_init (PhotosApplication *self)
 
   eog_debug_init ();
 
+  photos_utils_ensure_builtins ();
+
   priv->search_provider = photos_search_provider_new ();
   g_signal_connect_swapped (priv->search_provider,
                             "activate-result",
diff --git a/src/photos-facebook-item.c b/src/photos-facebook-item.c
index 17bbc04..9e6245c 100644
--- a/src/photos-facebook-item.c
+++ b/src/photos-facebook-item.c
@@ -47,7 +47,13 @@ struct _PhotosFacebookItemPrivate
 };
 
 
-G_DEFINE_TYPE_WITH_PRIVATE (PhotosFacebookItem, photos_facebook_item, PHOTOS_TYPE_BASE_ITEM);
+G_DEFINE_TYPE_WITH_CODE (PhotosFacebookItem, photos_facebook_item, PHOTOS_TYPE_BASE_ITEM,
+                         G_ADD_PRIVATE (PhotosFacebookItem)
+                         photos_utils_ensure_extension_points ();
+                         g_io_extension_point_implement (PHOTOS_BASE_ITEM_EXTENSION_POINT_NAME,
+                                                         g_define_type_id,
+                                                         "facebook",
+                                                         0));
 
 
 static GFBGraphPhoto *
diff --git a/src/photos-flickr-item.c b/src/photos-flickr-item.c
index 019d680..51b1b76 100644
--- a/src/photos-flickr-item.c
+++ b/src/photos-flickr-item.c
@@ -47,7 +47,13 @@ struct _PhotosFlickrItemPrivate
 };
 
 
-G_DEFINE_TYPE_WITH_PRIVATE (PhotosFlickrItem, photos_flickr_item, PHOTOS_TYPE_BASE_ITEM);
+G_DEFINE_TYPE_WITH_CODE (PhotosFlickrItem, photos_flickr_item, PHOTOS_TYPE_BASE_ITEM,
+                         G_ADD_PRIVATE (PhotosFlickrItem)
+                         photos_utils_ensure_extension_points ();
+                         g_io_extension_point_implement (PHOTOS_BASE_ITEM_EXTENSION_POINT_NAME,
+                                                         g_define_type_id,
+                                                         "flickr",
+                                                         0));
 
 
 typedef struct _PhotosFlickrItemSyncData PhotosFlickrItemSyncData;
diff --git a/src/photos-local-item.c b/src/photos-local-item.c
index 99604b7..8c8faba 100644
--- a/src/photos-local-item.c
+++ b/src/photos-local-item.c
@@ -1,6 +1,6 @@
 /*
  * Photos - access, organize and share your photos on GNOME
- * Copyright © 2012, 2013 Red Hat, Inc.
+ * Copyright © 2012, 2013, 2014 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
@@ -33,7 +33,12 @@
 #include "photos-utils.h"
 
 
-G_DEFINE_TYPE (PhotosLocalItem, photos_local_item, PHOTOS_TYPE_BASE_ITEM);
+G_DEFINE_TYPE_WITH_CODE (PhotosLocalItem, photos_local_item, PHOTOS_TYPE_BASE_ITEM,
+                         photos_utils_ensure_extension_points ();
+                         g_io_extension_point_implement (PHOTOS_BASE_ITEM_EXTENSION_POINT_NAME,
+                                                         g_define_type_id,
+                                                         "local",
+                                                         0));
 
 
 static gboolean
diff --git a/src/photos-utils.c b/src/photos-utils.c
index 9c02c6d..7ece6b0 100644
--- a/src/photos-utils.c
+++ b/src/photos-utils.c
@@ -35,6 +35,10 @@
 #include <libgd/gd.h>
 
 #include "photos-application.h"
+#include "photos-base-item.h"
+#include "photos-facebook-item.h"
+#include "photos-flickr-item.h"
+#include "photos-local-item.h"
 #include "photos-query.h"
 #include "photos-tracker-queue.h"
 #include "photos-utils.h"
@@ -364,6 +368,41 @@ photos_utils_dot_dir (void)
 }
 
 
+void
+photos_utils_ensure_builtins (void)
+{
+  static gsize once_init_value = 0;
+
+  photos_utils_ensure_extension_points ();
+
+  if (g_once_init_enter (&once_init_value))
+    {
+      g_type_ensure (PHOTOS_TYPE_FACEBOOK_ITEM);
+      g_type_ensure (PHOTOS_TYPE_FLICKR_ITEM);
+      g_type_ensure (PHOTOS_TYPE_LOCAL_ITEM);
+
+      g_once_init_leave (&once_init_value, 1);
+    }
+}
+
+
+void
+photos_utils_ensure_extension_points (void)
+{
+  static gsize once_init_value = 0;
+
+  if (g_once_init_enter (&once_init_value))
+    {
+      GIOExtensionPoint *extension_point;
+
+      extension_point = g_io_extension_point_register (PHOTOS_BASE_ITEM_EXTENSION_POINT_NAME);
+      g_io_extension_point_set_required_type (extension_point, PHOTOS_TYPE_BASE_ITEM);
+
+      g_once_init_leave (&once_init_value, 1);
+    }
+}
+
+
 GQuark
 photos_utils_error_quark (void)
 {
diff --git a/src/photos-utils.h b/src/photos-utils.h
index 97e6339..42bbee8 100644
--- a/src/photos-utils.h
+++ b/src/photos-utils.h
@@ -39,6 +39,8 @@ G_BEGIN_DECLS
 #define PHOTOS_FLASH_OFF (photos_utils_flash_off_quark ())
 #define PHOTOS_FLASH_ON (photos_utils_flash_on_quark ())
 
+#define PHOTOS_BASE_ITEM_EXTENSION_POINT_NAME "photos-base-item"
+
 #define PHOTOS_COLLECTION_SCREENSHOT \
   "http://www.semanticdesktop.org/ontologies/2007/03/22/nfo#image-category-screenshot";
 
@@ -54,6 +56,10 @@ GIcon           *photos_utils_get_icon_from_cursor        (TrackerSparqlCursor *
 
 const gchar     *photos_utils_dot_dir                     (void);
 
+void             photos_utils_ensure_builtins             (void);
+
+void             photos_utils_ensure_extension_points     (void);
+
 GQuark           photos_utils_error_quark                 (void);
 
 gchar           *photos_utils_filename_strip_extension    (const gchar *filename_with_extension);