kobj.h revision 194028
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: head/sys/sys/kobj.h 194028 2009-06-11 17:21:14Z avg $ 27 */ 28 29#ifndef _SYS_KOBJ_H_ 30#define _SYS_KOBJ_H_ 31 32/* 33 * Forward declarations 34 */ 35typedef struct kobj *kobj_t; 36typedef struct kobj_class *kobj_class_t; 37typedef struct kobj_method kobj_method_t; 38typedef int (*kobjop_t)(void); 39typedef struct kobj_ops *kobj_ops_t; 40typedef struct kobjop_desc *kobjop_desc_t; 41struct malloc_type; 42 43struct 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 62struct kobj_class { 63 KOBJ_CLASS_FIELDS; 64}; 65 66/* 67 * Implementation of kobj. 68 */ 69#define KOBJ_FIELDS \ 70 kobj_ops_t ops 71 72struct 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 82struct kobj_ops { 83 kobj_method_t *cache[KOBJ_CACHE_SIZE]; 84 kobj_class_t cls; 85}; 86 87struct 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#if 1 96#define KOBJMETHOD(NAME, FUNC) { &NAME##_desc, (kobjop_t) FUNC } 97#else /* notyet */ 98#define KOBJMETHOD(NAME, FUNC) \ 99 { &NAME##_desc, (kobjop_t) (1 ? FUNC : (NAME##_t *)NULL) } 100#endif 101 102/* 103 * 104 */ 105#define KOBJMETHOD_END { NULL, NULL } 106 107/* 108 * Declare a class (which should be defined in another file. 109 */ 110#define DECLARE_CLASS(name) extern struct kobj_class name 111 112/* 113 * Define a class with no base classes (api backward-compatible. with 114 * FreeBSD-5.1 and earlier). 115 */ 116#define DEFINE_CLASS(name, methods, size) \ 117DEFINE_CLASS_0(name, name ## _class, methods, size) 118 119/* 120 * Define a class with no base classes. Use like this: 121 * 122 * DEFINE_CLASS_0(foo, foo_class, foo_methods, sizeof(foo_softc)); 123 */ 124#define DEFINE_CLASS_0(name, classvar, methods, size) \ 125 \ 126struct kobj_class classvar = { \ 127 #name, methods, size, NULL \ 128} 129 130/* 131 * Define a class inheriting a single base class. Use like this: 132 * 133 * DEFINE_CLASS_1(foo, foo_class, foo_methods, sizeof(foo_softc), 134 * bar); 135 */ 136#define DEFINE_CLASS_1(name, classvar, methods, size, \ 137 base1) \ 138 \ 139static kobj_class_t name ## _baseclasses[] = \ 140 { &base1, NULL }; \ 141struct kobj_class classvar = { \ 142 #name, methods, size, name ## _baseclasses \ 143} 144 145/* 146 * Define a class inheriting two base classes. Use like this: 147 * 148 * DEFINE_CLASS_2(foo, foo_class, foo_methods, sizeof(foo_softc), 149 * bar, baz); 150 */ 151#define DEFINE_CLASS_2(name, methods, size, \ 152 base1, base2) \ 153 \ 154static kobj_class_t name ## _baseclasses[] = \ 155 { &base1, \ 156 &base2, NULL }; \ 157struct kobj_class name ## _class = { \ 158 #name, methods, size, name ## _baseclasses \ 159} 160 161/* 162 * Define a class inheriting three base classes. Use like this: 163 * 164 * DEFINE_CLASS_3(foo, foo_class, foo_methods, sizeof(foo_softc), 165 * bar, baz, foobar); 166 */ 167#define DEFINE_CLASS_3(name, methods, size, \ 168 base1, base2, base3) \ 169 \ 170static kobj_class_t name ## _baseclasses[] = \ 171 { &base1, \ 172 &base2, \ 173 &base3, NULL }; \ 174struct kobj_class name ## _class = { \ 175 #name, methods, size, name ## _baseclasses \ 176} 177 178 179/* 180 * Compile the method table in a class. 181 */ 182void kobj_class_compile(kobj_class_t cls); 183 184/* 185 * Compile the method table, with the caller providing the space for 186 * the ops table.(for use before malloc is initialised). 187 */ 188void kobj_class_compile_static(kobj_class_t cls, kobj_ops_t ops); 189 190/* 191 * Free the compiled method table in a class. 192 */ 193void kobj_class_free(kobj_class_t cls); 194 195/* 196 * Allocate memory for and initialise a new object. 197 */ 198kobj_t kobj_create(kobj_class_t cls, 199 struct malloc_type *mtype, 200 int mflags); 201 202/* 203 * Initialise a pre-allocated object. 204 */ 205void kobj_init(kobj_t obj, kobj_class_t cls); 206 207/* 208 * Delete an object. If mtype is non-zero, free the memory. 209 */ 210void kobj_delete(kobj_t obj, struct malloc_type *mtype); 211 212/* 213 * Maintain stats on hits/misses in lookup caches. 214 */ 215#ifdef KOBJ_STATS 216extern u_int kobj_lookup_hits; 217extern u_int kobj_lookup_misses; 218#endif 219 220/* 221 * Lookup the method in the cache and if it isn't there look it up the 222 * slow way. 223 */ 224#ifdef KOBJ_STATS 225#define KOBJOPLOOKUP(OPS,OP) do { \ 226 kobjop_desc_t _desc = &OP##_##desc; \ 227 kobj_method_t **_cep = \ 228 &OPS->cache[_desc->id & (KOBJ_CACHE_SIZE-1)]; \ 229 kobj_method_t *_ce = *_cep; \ 230 kobj_lookup_hits++; /* assume hit */ \ 231 if (_ce->desc != _desc) \ 232 _ce = kobj_lookup_method(OPS->cls, \ 233 _cep, _desc); \ 234 _m = _ce->func; \ 235} while(0) 236#else 237#define KOBJOPLOOKUP(OPS,OP) do { \ 238 kobjop_desc_t _desc = &OP##_##desc; \ 239 kobj_method_t **_cep = \ 240 &OPS->cache[_desc->id & (KOBJ_CACHE_SIZE-1)]; \ 241 kobj_method_t *_ce = *_cep; \ 242 if (_ce->desc != _desc) \ 243 _ce = kobj_lookup_method(OPS->cls, \ 244 _cep, _desc); \ 245 _m = _ce->func; \ 246} while(0) 247#endif 248 249kobj_method_t* kobj_lookup_method(kobj_class_t cls, 250 kobj_method_t **cep, 251 kobjop_desc_t desc); 252 253 254/* 255 * Default method implementation. Returns ENXIO. 256 */ 257int kobj_error_method(void); 258 259#endif /* !_SYS_KOBJ_H_ */ 260