~vcs-imports/libgnome/master

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/* gnome-macros.h
 *   Macros for making GObject objects to avoid typos and reduce code size
 * Copyright (C) 2000  Eazel, Inc.
 *
 * Authors: George Lebl <jirka@5z.com>
 *
 * All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */
/*
  @NOTATION@
*/

#ifndef GNOME_MACROS_H
#define GNOME_MACROS_H

/* Macros for defining classes.  Ideas taken from Nautilus and GOB. */

/* Define the boilerplate type stuff to reduce typos and code size.  Defines
 * the get_type method and the parent_class static variable. */
#define GNOME_CLASS_BOILERPLATE(type, type_as_function,			\
				parent_type, parent_type_as_function,	\
				parent_type_macro)			\
static void type_as_function ## _class_init    (type ## Class *klass);	\
static void type_as_function ## _instance_init (type          *object);	\
static parent_type ## Class *parent_class = NULL;			\
GType									\
type_as_function ## _get_type (void)					\
{									\
	static GType object_type = 0;					\
	if (object_type == 0) {						\
		static const GTypeInfo object_info = {			\
		    sizeof (type ## Class),				\
		    (GBaseInitFunc)         NULL,			\
		    (GBaseFinalizeFunc)     NULL,			\
		    (GClassInitFunc)        type_as_function ## _class_init, \
		    NULL,                   /* class_finalize */	\
		    NULL,                   /* class_data */		\
		    sizeof (type),					\
		    0,                      /* n_preallocs */		\
		    (GInstanceInitFunc)     type_as_function ## _instance_init \
		};							\
		object_type = g_type_register_static			\
		    (parent_type_macro, #type, &object_info, 0);	\
		parent_class = g_type_class_ref (parent_type_macro);	\
	}								\
	return object_type;						\
}

/* Just call the parent handler.  This assumes that there is a variable
 * named parent_class that points to the (duh!) parent class.  Note that
 * this macro is not to be used with things that return something, use
 * the _WITH_DEFAULT version for that */
#define GNOME_CALL_PARENT_HANDLER(parent_class_cast, name, args)	\
	((parent_class_cast(parent_class)->name != NULL) ?		\
	 parent_class_cast(parent_class)->name args : (void)0)

/* Same as above, but in case there is no implementation, it evaluates
 * to def_return */
#define GNOME_CALL_PARENT_HANDLER_WITH_DEFAULT(parent_class_cast,	\
					       name, args, def_return)	\
	((parent_class_cast(parent_class)->name != NULL) ?		\
	 parent_class_cast(parent_class)->name args : def_return)

#endif /* GNOME_MACROS_H */