[gegl] Fix initiazation order

[Daniel Sabo <daniels src gnome org>]

commit 6c11f31bec6c78c30b856fe59422cfffb0c9a080
Author: Daniel Sabo <DanielSabo gmail com>
Date:   Sat Mar 30 23:26:29 2013 -0700

    Fix initiazation order
    
    GObject introspection would crash when opencl was available because
    it constructed a GeglConfig object without calling gegl_init. However
    this was only part of the problem because calling gegl_config before
    init will cause gegl_init to silently bail out without actually
    setting up Gegl.
    
    In order to both avoid the introspection crash and allow the user to
    modify settings before calling gegl_init  I've switched to the
    slightly ugly notify::use-opencl based trigger for gegl_cl_init.
    I also changed gegl_init to track it's own state instead of checking
    for the existence of GeglConfig.

 gegl/gegl-config.c |    4 ----
 gegl/gegl-init.c   |   42 +++++++++++++++++++++++++++++++++++++-----
 2 files changed, 37 insertions(+), 9 deletions(-)
---
diff --git a/gegl/gegl-config.c b/gegl/gegl-config.c
index e985f78..9d67bd9 100644
--- a/gegl/gegl-config.c
+++ b/gegl/gegl-config.c
@@ -176,10 +176,6 @@ gegl_config_set_property (GObject      *gobject,
         return;
       case PROP_USE_OPENCL:
         config->use_opencl = g_value_get_boolean (value);
-
-        if (config->use_opencl)
-          config->use_opencl = gegl_cl_init (NULL);
-
         break;
       case PROP_QUEUE_LIMIT:
         config->queue_limit = g_value_get_int (value);
diff --git a/gegl/gegl-init.c b/gegl/gegl-init.c
index 86a377b..1aab900 100644
--- a/gegl/gegl-init.c
+++ b/gegl/gegl-init.c
@@ -164,6 +164,32 @@ static glong         global_time = 0;
 static const gchar *makefile (void);
 
 static void
+gegl_config_use_opencl_notify (GObject    *gobject,
+                               GParamSpec *pspec,
+                               gpointer    user_data)
+{
+  GeglConfig *cfg = GEGL_CONFIG (gobject);
+  gboolean use_opencl = cfg->use_opencl;
+
+  if (use_opencl)
+  {
+    g_signal_handlers_block_by_func (gobject,
+                                     gegl_config_use_opencl_notify,
+                                     NULL);
+
+    use_opencl = gegl_cl_init (NULL);
+
+    g_object_set (gobject,
+                  "use-opencl", use_opencl,
+                  NULL);
+
+    g_signal_handlers_unblock_by_func (gobject,
+                                       gegl_config_use_opencl_notify,
+                                       NULL);
+  }
+}
+
+static void
 gegl_init_i18n (void)
 {
   setlocale (LC_ALL, "");
@@ -177,9 +203,13 @@ gegl_init (gint    *argc,
 {
   GOptionContext *context;
   GError         *error = NULL;
-  if (config)
+  static gboolean initialized = FALSE;
+
+  if (initialized)
     return;
 
+  initialized = TRUE;
+
   gegl_init_i18n ();
 
   context = g_option_context_new (NULL);
@@ -469,10 +499,6 @@ gegl_post_parse_hook (GOptionContext *context,
 {
   glong time;
 
-  if (config)
-    return TRUE;
-
-
   g_assert (global_time == 0);
   global_time = gegl_ticks ();
   g_type_init ();
@@ -599,6 +625,12 @@ gegl_post_parse_hook (GOptionContext *context,
 
   swap_clean ();
 
+  g_signal_connect (G_OBJECT (config),
+                   "notify::use-opencl",
+                   G_CALLBACK (gegl_config_use_opencl_notify),
+                   NULL);
+  g_object_set (config, "use-opencl", config->use_opencl, NULL);
+
   return TRUE;
 }