FreeBSD/Linux Kernel Cross Reference
sys/sys/kobj.h
1 /*-
2 * Copyright (c) 2000,2003 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/5.2/sys/sys/kobj.h 121129 2003-10-16 09:16:28Z dfr $
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 kobj_class_t *baseclasses; /* base classes */ \
59 u_int refs; /* reference count */ \
60 kobj_ops_t ops /* compiled method table */
61
62 struct kobj_class {
63 KOBJ_CLASS_FIELDS;
64 };
65
66 /*
67 * Implementation of kobj.
68 */
69 #define KOBJ_FIELDS \
70 kobj_ops_t ops
71
72 struct kobj {
73 KOBJ_FIELDS;
74 };
75
76 /*
77 * The ops table is used as a cache of results from kobj_lookup_method().
78 */
79
80 #define KOBJ_CACHE_SIZE 256
81
82 struct kobj_ops {
83 kobj_method_t *cache[KOBJ_CACHE_SIZE];
84 kobj_class_t cls;
85 };
86
87 struct kobjop_desc {
88 unsigned int id; /* unique ID */
89 kobj_method_t *deflt; /* default implementation */
90 };
91
92 /*
93 * Shorthand for constructing method tables.
94 */
95 #define KOBJMETHOD(NAME, FUNC) { &NAME##_desc, (kobjop_t) FUNC }
96
97 /*
98 * Declare a class (which should be defined in another file.
99 */
100 #define DECLARE_CLASS(name) extern struct kobj_class name
101
102 /*
103 * Define a class with no base classes (api backward-compatible. with
104 * FreeBSD-5.1 and earlier).
105 */
106 #define DEFINE_CLASS(name, methods, size) \
107 DEFINE_CLASS_0(name, name ## _class, methods, size)
108
109 /*
110 * Define a class with no base classes. Use like this:
111 *
112 * DEFINE_CLASS_0(foo, foo_class, foo_methods, sizeof(foo_softc));
113 */
114 #define DEFINE_CLASS_0(name, classvar, methods, size) \
115 \
116 struct kobj_class classvar = { \
117 #name, methods, size, 0 \
118 }
119
120 /*
121 * Define a class inheriting a single base class. Use like this:
122 *
123 * DEFINE_CLASS1(foo, foo_class, foo_methods, sizeof(foo_softc),
124 * bar);
125 */
126 #define DEFINE_CLASS_1(name, classvar, methods, size, \
127 base1) \
128 \
129 static kobj_class_t name ## _baseclasses[] = \
130 { &base1, 0 }; \
131 struct kobj_class classvar = { \
132 #name, methods, size, name ## _baseclasses \
133 }
134
135 /*
136 * Define a class inheriting two base classes. Use like this:
137 *
138 * DEFINE_CLASS2(foo, foo_class, foo_methods, sizeof(foo_softc),
139 * bar, baz);
140 */
141 #define DEFINE_CLASS_2(name, methods, size, \
142 base1, base2) \
143 \
144 static kobj_class_t name ## _baseclasses[] = \
145 { &base1, \
146 &base2, 0 }; \
147 struct kobj_class name ## _class = { \
148 #name, methods, size, name ## _baseclasses \
149 }
150
151 /*
152 * Define a class inheriting three base classes. Use like this:
153 *
154 * DEFINE_CLASS3(foo, foo_class, foo_methods, sizeof(foo_softc),
155 * bar, baz, foobar);
156 */
157 #define DEFINE_CLASS_3(name, methods, size, \
158 base1, base2, base3) \
159 \
160 static kobj_class_t name ## _baseclasses[] = \
161 { &base1, \
162 &base2, \
163 &base3, 0 }; \
164 struct kobj_class name ## _class = { \
165 #name, methods, size, name ## _baseclasses \
166 }
167
168
169 /*
170 * Compile the method table in a class.
171 */
172 void kobj_class_compile(kobj_class_t cls);
173
174 /*
175 * Compile the method table, with the caller providing the space for
176 * the ops table.(for use before malloc is initialised).
177 */
178 void kobj_class_compile_static(kobj_class_t cls, kobj_ops_t ops);
179
180 /*
181 * Free the compiled method table in a class.
182 */
183 void kobj_class_free(kobj_class_t cls);
184
185 /*
186 * Allocate memory for and initialise a new object.
187 */
188 kobj_t kobj_create(kobj_class_t cls,
189 struct malloc_type *mtype,
190 int mflags);
191
192 /*
193 * Initialise a pre-allocated object.
194 */
195 void kobj_init(kobj_t obj, kobj_class_t cls);
196
197 /*
198 * Delete an object. If mtype is non-zero, free the memory.
199 */
200 void kobj_delete(kobj_t obj, struct malloc_type *mtype);
201
202 /*
203 * Maintain stats on hits/misses in lookup caches.
204 */
205 #ifdef KOBJ_STATS
206 extern u_int kobj_lookup_hits;
207 extern u_int kobj_lookup_misses;
208 #endif
209
210 /*
211 * Lookup the method in the cache and if it isn't there look it up the
212 * slow way.
213 */
214 #ifdef KOBJ_STATS
215 #define KOBJOPLOOKUP(OPS,OP) do { \
216 kobjop_desc_t _desc = &OP##_##desc; \
217 kobj_method_t **_cep = \
218 &OPS->cache[_desc->id & (KOBJ_CACHE_SIZE-1)]; \
219 kobj_method_t *_ce = *_cep; \
220 kobj_lookup_hits++; /* assume hit */ \
221 if (_ce->desc != _desc) \
222 _ce = kobj_lookup_method(OPS->cls, \
223 _cep, _desc); \
224 _m = _ce->func; \
225 } while(0)
226 #else
227 #define KOBJOPLOOKUP(OPS,OP) do { \
228 kobjop_desc_t _desc = &OP##_##desc; \
229 kobj_method_t **_cep = \
230 &OPS->cache[_desc->id & (KOBJ_CACHE_SIZE-1)]; \
231 kobj_method_t *_ce = *_cep; \
232 if (_ce->desc != _desc) \
233 _ce = kobj_lookup_method(OPS->cls, \
234 _cep, _desc); \
235 _m = _ce->func; \
236 } while(0)
237 #endif
238
239 kobj_method_t* kobj_lookup_method(kobj_class_t cls,
240 kobj_method_t **cep,
241 kobjop_desc_t desc);
242
243
244 /*
245 * Default method implementation. Returns ENXIO.
246 */
247 int kobj_error_method(void);
248
249 #endif /* !_SYS_KOBJ_H_ */
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