FreeBSD/Linux Kernel Cross Reference
sys/sys/kobj.h
1 /*-
2 * Copyright (c) 2000 Doug Rabson
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD: releng/5.1/sys/sys/kobj.h 98105 2002-06-10 22:40:26Z kbyanc $
27 */
28
29 #ifndef _SYS_KOBJ_H_
30 #define _SYS_KOBJ_H_
31
32 /*
33 * Forward declarations
34 */
35 typedef struct kobj *kobj_t;
36 typedef struct kobj_class *kobj_class_t;
37 typedef struct kobj_method kobj_method_t;
38 typedef int (*kobjop_t)(void);
39 typedef struct kobj_ops *kobj_ops_t;
40 typedef struct kobjop_desc *kobjop_desc_t;
41 struct malloc_type;
42
43 struct kobj_method {
44 kobjop_desc_t desc;
45 kobjop_t func;
46 };
47
48 /*
49 * A class is simply a method table and a sizeof value. When the first
50 * instance of the class is created, the method table will be compiled
51 * into a form more suited to efficient method dispatch. This compiled
52 * method table is always the first field of the object.
53 */
54 #define KOBJ_CLASS_FIELDS \
55 const char *name; /* class name */ \
56 kobj_method_t *methods; /* method table */ \
57 size_t size; /* object size */ \
58 u_int refs; /* reference count */ \
59 kobj_ops_t ops /* compiled method table */
60
61 struct kobj_class {
62 KOBJ_CLASS_FIELDS;
63 };
64
65 /*
66 * Implementation of kobj.
67 */
68 #define KOBJ_FIELDS \
69 kobj_ops_t ops
70
71 struct kobj {
72 KOBJ_FIELDS;
73 };
74
75 /*
76 * The ops table is used as a cache of results from kobj_lookup_method().
77 */
78
79 #define KOBJ_CACHE_SIZE 256
80
81 struct kobj_ops {
82 kobj_method_t cache[KOBJ_CACHE_SIZE];
83 kobj_class_t cls;
84 };
85
86 struct kobjop_desc {
87 unsigned int id; /* unique ID */
88 kobjop_t deflt; /* default implementation */
89 };
90
91 /*
92 * Shorthand for constructing method tables.
93 */
94 #define KOBJMETHOD(NAME, FUNC) { &NAME##_desc, (kobjop_t) FUNC }
95
96 #define DEFINE_CLASS(name, methods, size) \
97 \
98 struct kobj_class name ## _class = { \
99 #name, methods, size \
100 }
101
102 /*
103 * Compile the method table in a class.
104 */
105 void kobj_class_compile(kobj_class_t cls);
106
107 /*
108 * Compile the method table, with the caller providing the space for
109 * the ops table.(for use before malloc is initialised).
110 */
111 void kobj_class_compile_static(kobj_class_t cls, kobj_ops_t ops);
112
113 /*
114 * Free the compiled method table in a class.
115 */
116 void kobj_class_free(kobj_class_t cls);
117
118 /*
119 * Allocate memory for and initialise a new object.
120 */
121 kobj_t kobj_create(kobj_class_t cls,
122 struct malloc_type *mtype,
123 int mflags);
124
125 /*
126 * Initialise a pre-allocated object.
127 */
128 void kobj_init(kobj_t obj, kobj_class_t cls);
129
130 /*
131 * Delete an object. If mtype is non-zero, free the memory.
132 */
133 void kobj_delete(kobj_t obj, struct malloc_type *mtype);
134
135 /*
136 * Maintain stats on hits/misses in lookup caches.
137 */
138 #ifdef KOBJ_STATS
139 extern u_int kobj_lookup_hits;
140 extern u_int kobj_lookup_misses;
141 #define KOBJOPHIT do { kobj_lookup_hits++; } while (0)
142 #define KOBJOPMISS do { kobj_lookup_misses++; } while (0)
143 #else
144 #define KOBJOPHIT do { } while (0)
145 #define KOBJOPMISS do { } while (0)
146 #endif
147
148 /*
149 * Lookup the method in the cache and if it isn't there look it up the
150 * slow way.
151 */
152 #define KOBJOPLOOKUP(OPS,OP) do { \
153 kobjop_desc_t _desc = &OP##_##desc; \
154 kobj_method_t *_ce = \
155 &OPS->cache[_desc->id & (KOBJ_CACHE_SIZE-1)]; \
156 if (_ce->desc != _desc) { \
157 KOBJOPMISS; \
158 kobj_lookup_method(OPS->cls->methods, _ce, _desc); \
159 } else { \
160 KOBJOPHIT; \
161 } \
162 _m = _ce->func; \
163 } while(0)
164
165 void kobj_lookup_method(kobj_method_t *methods,
166 kobj_method_t *ce,
167 kobjop_desc_t desc);
168
169 #endif /* !_SYS_KOBJ_H_ */
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