1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 1999 Michael Smith <msmith@freebsd.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#ifndef _SYS__EVENTHANDLER_H_
30#define _SYS__EVENTHANDLER_H_
31
32#include <sys/queue.h>
33
34struct eventhandler_entry {
35 TAILQ_ENTRY(eventhandler_entry) ee_link;
36 int ee_priority;
37#define EHE_DEAD_PRIORITY (-1)
38 void *ee_arg;
39};
40
41typedef struct eventhandler_entry *eventhandler_tag;
42
43/*
44 * You can optionally use the EVENTHANDLER_LIST and EVENTHANDLER_DIRECT macros
45 * to pre-define a symbol for the eventhandler list. This symbol can be used by
46 * EVENTHANDLER_DIRECT_INVOKE, which has the advantage of not needing to do a
47 * locked search of the global list of eventhandler lists. At least
48 * EVENTHANDLER_LIST_DEFINE must be used for EVENTHANDLER_DIRECT_INVOKE to
49 * work. EVENTHANDLER_LIST_DECLARE is only needed if the call to
50 * EVENTHANDLER_DIRECT_INVOKE is in a different compilation unit from
51 * EVENTHANDLER_LIST_DEFINE. If the events are even relatively high frequency
52 * it is suggested that you directly define a list for them.
53 */
54struct eventhandler_list;
55#define EVENTHANDLER_LIST_DECLARE(name) \
56extern struct eventhandler_list *_eventhandler_list_ ## name \
57
58/*
59 * Event handlers need to be declared, but do not need to be defined. The
60 * declaration must be in scope wherever the handler is to be invoked.
61 */
62#define EVENTHANDLER_DECLARE(name, type) \
63struct eventhandler_entry_ ## name \
64{ \
65 struct eventhandler_entry ee; \
66 type eh_func; \
67}; \
68struct __hack
69
70#endif