freebsd-nq/sys/sys/_eventhandler.h
2020-07-25 07:48:20 +00:00

73 lines
2.8 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 1999 Michael Smith <msmith@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#ifndef _SYS__EVENTHANDLER_H_
#define _SYS__EVENTHANDLER_H_
#include <sys/queue.h>
struct eventhandler_entry {
TAILQ_ENTRY(eventhandler_entry) ee_link;
int ee_priority;
#define EHE_DEAD_PRIORITY (-1)
void *ee_arg;
};
typedef struct eventhandler_entry *eventhandler_tag;
/*
* You can optionally use the EVENTHANDLER_LIST and EVENTHANDLER_DIRECT macros
* to pre-define a symbol for the eventhandler list. This symbol can be used by
* EVENTHANDLER_DIRECT_INVOKE, which has the advantage of not needing to do a
* locked search of the global list of eventhandler lists. At least
* EVENTHANDLER_LIST_DEFINE must be be used for EVENTHANDLER_DIRECT_INVOKE to
* work. EVENTHANDLER_LIST_DECLARE is only needed if the call to
* EVENTHANDLER_DIRECT_INVOKE is in a different compilation unit from
* EVENTHANDLER_LIST_DEFINE. If the events are even relatively high frequency
* it is suggested that you directly define a list for them.
*/
struct eventhandler_list;
#define EVENTHANDLER_LIST_DECLARE(name) \
extern struct eventhandler_list *_eventhandler_list_ ## name \
/*
* Event handlers need to be declared, but do not need to be defined. The
* declaration must be in scope wherever the handler is to be invoked.
*/
#define EVENTHANDLER_DECLARE(name, type) \
struct eventhandler_entry_ ## name \
{ \
struct eventhandler_entry ee; \
type eh_func; \
}; \
struct __hack
#endif