xref: /freebsd/sys/sys/_eventhandler.h (revision fab66680b3df4792fb0d3d13b2c9cdd88538d3d2)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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  * $FreeBSD$
29  */
30 
31 #ifndef _SYS__EVENTHANDLER_H_
32 #define _SYS__EVENTHANDLER_H_
33 
34 #include <sys/queue.h>
35 
36 struct eventhandler_entry {
37 	TAILQ_ENTRY(eventhandler_entry)	ee_link;
38 	int				ee_priority;
39 #define	EHE_DEAD_PRIORITY	(-1)
40 	void				*ee_arg;
41 };
42 
43 typedef struct eventhandler_entry	*eventhandler_tag;
44 
45 /*
46  * You can optionally use the EVENTHANDLER_LIST and EVENTHANDLER_DIRECT macros
47  * to pre-define a symbol for the eventhandler list. This symbol can be used by
48  * EVENTHANDLER_DIRECT_INVOKE, which has the advantage of not needing to do a
49  * locked search of the global list of eventhandler lists. At least
50  * EVENTHANDLER_LIST_DEFINE must be be used for EVENTHANDLER_DIRECT_INVOKE to
51  * work. EVENTHANDLER_LIST_DECLARE is only needed if the call to
52  * EVENTHANDLER_DIRECT_INVOKE is in a different compilation unit from
53  * EVENTHANDLER_LIST_DEFINE. If the events are even relatively high frequency
54  * it is suggested that you directly define a list for them.
55  */
56 struct eventhandler_list;
57 #define	EVENTHANDLER_LIST_DECLARE(name)					\
58 extern struct eventhandler_list *_eventhandler_list_ ## name		\
59 
60 /*
61  * Event handlers need to be declared, but do not need to be defined. The
62  * declaration must be in scope wherever the handler is to be invoked.
63  */
64 #define EVENTHANDLER_DECLARE(name, type)				\
65 struct eventhandler_entry_ ## name 					\
66 {									\
67 	struct eventhandler_entry	ee;				\
68 	type				eh_func;			\
69 };									\
70 struct __hack
71 
72 #endif
73 /*-
74  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
75  *
76  * Copyright (c) 1999 Michael Smith <msmith@freebsd.org>
77  * All rights reserved.
78  *
79  * Redistribution and use in source and binary forms, with or without
80  * modification, are permitted provided that the following conditions
81  * are met:
82  * 1. Redistributions of source code must retain the above copyright
83  *    notice, this list of conditions and the following disclaimer.
84  * 2. Redistributions in binary form must reproduce the above copyright
85  *    notice, this list of conditions and the following disclaimer in the
86  *    documentation and/or other materials provided with the distribution.
87  *
88  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
89  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
90  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
91  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
92  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
93  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
94  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
95  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
96  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
97  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
98  * SUCH DAMAGE.
99  *
100  * $FreeBSD$
101  */
102 
103 #ifndef _SYS__EVENTHANDLER_H_
104 #define _SYS__EVENTHANDLER_H_
105 
106 #include <sys/queue.h>
107 
108 struct eventhandler_entry {
109 	TAILQ_ENTRY(eventhandler_entry)	ee_link;
110 	int				ee_priority;
111 #define	EHE_DEAD_PRIORITY	(-1)
112 	void				*ee_arg;
113 };
114 
115 typedef struct eventhandler_entry	*eventhandler_tag;
116 
117 /*
118  * You can optionally use the EVENTHANDLER_LIST and EVENTHANDLER_DIRECT macros
119  * to pre-define a symbol for the eventhandler list. This symbol can be used by
120  * EVENTHANDLER_DIRECT_INVOKE, which has the advantage of not needing to do a
121  * locked search of the global list of eventhandler lists. At least
122  * EVENTHANDLER_LIST_DEFINE must be be used for EVENTHANDLER_DIRECT_INVOKE to
123  * work. EVENTHANDLER_LIST_DECLARE is only needed if the call to
124  * EVENTHANDLER_DIRECT_INVOKE is in a different compilation unit from
125  * EVENTHANDLER_LIST_DEFINE. If the events are even relatively high frequency
126  * it is suggested that you directly define a list for them.
127  */
128 struct eventhandler_list;
129 #define	EVENTHANDLER_LIST_DECLARE(name)					\
130 extern struct eventhandler_list *_eventhandler_list_ ## name		\
131 
132 /*
133  * Event handlers need to be declared, but do not need to be defined. The
134  * declaration must be in scope wherever the handler is to be invoked.
135  */
136 #define EVENTHANDLER_DECLARE(name, type)				\
137 struct eventhandler_entry_ ## name 					\
138 {									\
139 	struct eventhandler_entry	ee;				\
140 	type				eh_func;			\
141 };									\
142 struct __hack
143 
144 #endif
145