/*
 * CallWeaver -- An open source telephony toolkit.
 *
 * Copyright (C) 2007, Eris Associates Limited, UK
 *
 * Mike Jagdis <mjagdis@eris-associates.co.uk>
 *
 * See http://www.callweaver.org for more information about
 * the CallWeaver project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*! \file
 * \brief CallWeaver function handling
 */

#ifndef _CALLWEAVER_FUNCTION_H
#define _CALLWEAVER_FUNCTION_H

#include "callweaver/object.h"
#include "callweaver/registry.h"
#include "callweaver/module.h"


struct cw_channel;


/*! \brief structure associated with registering a function */
struct cw_func {
	struct cw_object obj;
	struct cw_registry_entry *reg_entry;
	unsigned int hash;
	int (*handler)(struct cw_channel *chan, int argc, char **argv, char *buf, size_t len);
	const char *name;
	const char *synopsis;
	const char *syntax;
	const char *description;
};


extern CW_API_PUBLIC const struct cw_object_isa cw_object_isa_function;
extern CW_API_PUBLIC struct cw_registry func_registry;


#define cw_function_register(ptr) ({ \
	const typeof(ptr) __ptr = (ptr); \
	/* We know 0 refs means not initialized because we know how objs work \
	 * internally and we know that registration only happens while the \
	 * module lock is held. \
	 */ \
	if (!cw_object_refs(__ptr)) \
		cw_object_init_obj(&__ptr->obj, &cw_object_isa_function, CW_OBJECT_CURRENT_MODULE, 0); \
	__ptr->reg_entry = cw_registry_add(&func_registry, cw_hash_string(__ptr->name), &__ptr->obj); \
	0; \
})
#define cw_function_unregister(ptr) ({ \
	const typeof(ptr) __ptr = (ptr); \
	if (__ptr->reg_entry) \
		cw_registry_del(&func_registry, __ptr->reg_entry); \
	0; \
})


/* Backwards compatibility */
#define cw_register_function(f_name, f_handler, f_synopsis, f_syntax, f_description) ({ \
	static struct cw_func f = { \
		.name = (f_name), \
		.handler = (f_handler), \
		.synopsis = (f_synopsis), \
		.syntax = (f_syntax), \
		.description = (f_description), \
	}; \
	cw_function_register(&f); \
	&f; \
})
#define cw_unregister_function(func) ({ \
	const struct cw_func *__func = (func); \
	if (__func) \
		cw_function_unregister(__func); \
	0; \
})


extern void cw_function_registry_initialize(void);


#endif /* _CALLWEAVER_FUNCTION_H */