[gnome-photos] application: Sanity check GEGL operations before creating the window

[Debarshi Ray <debarshir src gnome org>]

commit 1e7aec38c159ab3c52f34f8f8a0f1fcd42845572
Author: Debarshi Ray <debarshir gnome org>
Date:   Wed Jan 6 14:54:46 2016 +0100

    application: Sanity check GEGL operations before creating the window
    
    It's too easy to miss some GEGL operation due to not having the
    relevant dependencies while building. Let's check these things upfront
    to avoid weird behaviour later on.
    
    We perform these checks when creating the main window because the
    earlier stages are shared with the search provider. The search
    provider doesn't use GEGL and we want to keep it as lean as possible.

 src/photos-application.c |   61 +++++++++++++++++++++++++++++++++++++++++----
 1 files changed, 55 insertions(+), 6 deletions(-)
---
diff --git a/src/photos-application.c b/src/photos-application.c
index b1e50a0..3a1e99b 100644
--- a/src/photos-application.c
+++ b/src/photos-application.c
@@ -2,7 +2,7 @@
  * Photos - access, organize and share your photos on GNOME
  * Copyright © 2015 Alessandro Bono
  * Copyright © 2014, 2015 Pranav Kant
- * Copyright © 2012, 2013, 2014, 2015 Red Hat, Inc.
+ * Copyright © 2012, 2013, 2014, 2015, 2016 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
@@ -125,6 +125,26 @@ enum
   MINER_REFRESH_TIMEOUT = 60 /* s */
 };
 
+static const gchar *REQUIRED_GEGL_OPS[] =
+{
+  "gegl:buffer-sink",
+  "gegl:buffer-source",
+  "gegl:crop",
+  "gegl:gray",
+  "gegl:load",
+  "gegl:nop",
+  "gegl:rotate-on-center",
+  "gegl:save-pixbuf",
+  "gegl:scale-ratio",
+
+  /* Used by gegl:load */
+  "gegl:jp2-load",
+  "gegl:jpg-load",
+  "gegl:png-load",
+  "gegl:raw-load",
+  "gegl:text"
+};
+
 static const gchar *DESKTOP_BACKGROUND_SCHEMA = "org.gnome.desktop.background";
 static const gchar *DESKTOP_SCREENSAVER_SCHEMA = "org.gnome.desktop.screensaver";
 static const gchar *DESKTOP_KEY_PICTURE_URI = "picture-uri";
@@ -428,6 +448,26 @@ photos_application_create_miners (PhotosApplication *self)
 }
 
 
+static gboolean
+photos_application_sanity_check_gegl (PhotosApplication *self)
+{
+  gboolean ret_val = TRUE;
+  guint i;
+
+  for (i = 0; i < G_N_ELEMENTS (REQUIRED_GEGL_OPS); i++)
+    {
+      if (!gegl_has_operation (REQUIRED_GEGL_OPS[i]))
+        {
+          g_warning ("Unable to find GEGL operation %s: Check your GEGL install", REQUIRED_GEGL_OPS[i]);
+          ret_val = FALSE;
+          break;
+        }
+    }
+
+  return ret_val;
+}
+
+
 static void
 photos_application_tracker_set_rdf_types (GObject *source_object, GAsyncResult *res, gpointer user_data)
 {
@@ -479,13 +519,15 @@ photos_application_tracker_extract_priority (GObject *source_object, GAsyncResul
 }
 
 
-static void
+static gboolean
 photos_application_create_window (PhotosApplication *self)
 {
   PhotosApplicationPrivate *priv = self->priv;
 
   if (priv->main_window != NULL)
-    return;
+    return TRUE;
+
+  g_return_val_if_fail (photos_application_sanity_check_gegl (self), FALSE);
 
   priv->main_window = photos_main_window_new (GTK_APPLICATION (self));
   g_signal_connect_swapped (priv->main_window, "destroy", G_CALLBACK (photos_application_destroy), self);
@@ -500,6 +542,7 @@ photos_application_create_window (PhotosApplication *self)
                                               self);
 
   photos_application_start_miners (self);
+  return TRUE;
 }
 
 
@@ -508,7 +551,9 @@ photos_application_activate_item (PhotosApplication *self, GObject *item)
 {
   PhotosApplicationPrivate *priv = self->priv;
 
-  photos_application_create_window (self);
+  if (!photos_application_create_window (self))
+    return;
+
   photos_base_manager_set_active_object (priv->state->item_mngr, item);
   g_application_activate (G_APPLICATION (self));
 
@@ -690,7 +735,9 @@ photos_application_launch_search (PhotosApplication *self, const gchar* const *t
   GVariant *state;
   gchar *str;
 
-  photos_application_create_window (self);
+  if (!photos_application_create_window (self))
+    return;
+
   photos_mode_controller_set_window_mode (priv->state->mode_cntrlr, PHOTOS_WINDOW_MODE_OVERVIEW);
 
   str = g_strjoinv (" ", (gchar **) terms);
@@ -1139,7 +1186,9 @@ photos_application_activate (GApplication *application)
 
   if (priv->main_window == NULL)
     {
-      photos_application_create_window (self);
+      if (!photos_application_create_window (self))
+        return;
+
       photos_mode_controller_set_window_mode (priv->state->mode_cntrlr, PHOTOS_WINDOW_MODE_OVERVIEW);
     }