kobj.h revision 186347
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 186347 2008-12-20 00:33:10Z nwhitehorn $ 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#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) \ 107DEFINE_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 \ 116struct 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_CLASS_1(foo, foo_class, foo_methods, sizeof(foo_softc), 124 * bar); 125 */ 126#define DEFINE_CLASS_1(name, classvar, methods, size, \ 127 base1) \ 128 \ 129static kobj_class_t name ## _baseclasses[] = \ 130 { &base1, 0 }; \ 131struct 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_CLASS_2(foo, foo_class, foo_methods, sizeof(foo_softc), 139 * bar, baz); 140 */ 141#define DEFINE_CLASS_2(name, methods, size, \ 142 base1, base2) \ 143 \ 144static kobj_class_t name ## _baseclasses[] = \ 145 { &base1, \ 146 &base2, 0 }; \ 147struct 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_CLASS_3(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 \ 160static kobj_class_t name ## _baseclasses[] = \ 161 { &base1, \ 162 &base2, \ 163 &base3, 0 }; \ 164struct kobj_class name ## _class = { \ 165 #name, methods, size, name ## _baseclasses \ 166} 167 168 169/* 170 * Compile the method table in a class. 171 */ 172void 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 */ 178void kobj_class_compile_static(kobj_class_t cls, kobj_ops_t ops); 179 180/* 181 * Free the compiled method table in a class. 182 */ 183void kobj_class_free(kobj_class_t cls); 184 185/* 186 * Allocate memory for and initialise a new object. 187 */ 188kobj_t kobj_create(kobj_class_t cls, 189 struct malloc_type *mtype, 190 int mflags); 191 192/* 193 * Initialise a pre-allocated object. 194 */ 195void kobj_init(kobj_t obj, kobj_class_t cls); 196 197/* 198 * Delete an object. If mtype is non-zero, free the memory. 199 */ 200void 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 206extern u_int kobj_lookup_hits; 207extern 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 239kobj_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 */ 247int kobj_error_method(void); 248 249#endif /* !_SYS_KOBJ_H_ */ 250