1/* GObject - GLib Type, Object, Parameter and Signal Library
2 * Copyright (C) 2006 Imendio AB
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General
15 * Public License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
17 * Boston, MA 02111-1307, USA.
18 */
19#undef  G_LOG_DOMAIN
20#define G_LOG_DOMAIN "TestSingleton"
21#include <glib-object.h>
22#include <string.h>
23
24/* --- MySingleton class --- */
25typedef struct {
26  GObject parent_instance;
27} MySingleton;
28typedef struct {
29  GObjectClass parent_class;
30} MySingletonClass;
31
32#define MY_TYPE_SINGLETON         (my_singleton_get_type ())
33#define MY_SINGLETON(o)           (G_TYPE_CHECK_INSTANCE_CAST ((o), MY_TYPE_SINGLETON, MySingleton))
34#define MY_IS_SINGLETON(o)        (G_TYPE_CHECK_INSTANCE_TYPE ((o), MY_TYPE_SINGLETON))
35#define MY_SINGLETON_CLASS(c)     (G_TYPE_CHECK_CLASS_CAST ((c), MY_TYPE_SINGLETON, MySingletonClass))
36#define MY_IS_SINGLETON_CLASS(c)  (G_TYPE_CHECK_CLASS_TYPE ((c), MY_TYPE_SINGLETON))
37#define MY_SINGLETON_GET_CLASS(o) (G_TYPE_INSTANCE_GET_CLASS ((o), MY_TYPE_SINGLETON, MySingletonClass))
38
39G_DEFINE_TYPE (MySingleton, my_singleton, G_TYPE_OBJECT);
40
41static MySingleton *the_one_and_only = NULL;
42
43/* --- methods --- */
44static GObject*
45my_singleton_constructor (GType                  type,
46                          guint                  n_construct_properties,
47                          GObjectConstructParam *construct_properties)
48{
49  if (the_one_and_only)
50    return g_object_ref (the_one_and_only);
51  else
52    return G_OBJECT_CLASS (my_singleton_parent_class)->constructor (type, n_construct_properties, construct_properties);
53}
54
55static void
56my_singleton_init (MySingleton *self)
57{
58  g_assert (the_one_and_only == NULL);
59  the_one_and_only = self;
60}
61
62static void
63my_singleton_class_init (MySingletonClass *klass)
64{
65  G_OBJECT_CLASS (klass)->constructor = my_singleton_constructor;
66}
67
68/* --- test program --- */
69int
70main (int   argc,
71      char *argv[])
72{
73  MySingleton *singleton, *obj;
74  g_type_init_with_debug_flags (G_TYPE_DEBUG_OBJECTS | G_TYPE_DEBUG_SIGNALS);
75  /* create the singleton */
76  singleton = g_object_new (MY_TYPE_SINGLETON, NULL);
77  g_assert (singleton != NULL);
78  /* assert _singleton_ creation */
79  obj = g_object_new (MY_TYPE_SINGLETON, NULL);
80  g_assert (singleton == obj);
81  g_object_unref (obj);
82  /* shutdown */
83  g_object_unref (singleton);
84  return 0;
85}
86