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: src/sys/sys/kobj.h,v 1.8 2003/09/22 21:32:49 peter Exp $
  27  * $DragonFly: src/sys/sys/kobj.h,v 1.9 2005/03/08 17:43:33 joerg Exp $
  28  */
  29
  30 #ifndef _SYS_KOBJ_H_
  31 #define _SYS_KOBJ_H_
  32
  33 #if !defined(_KERNEL) && !defined(_KERNEL_STRUCTURES)
  34 #error "This file should not be included by userland programs."
  35 #endif
  36
  37 /*
  38  * Forward declarations
  39  */
  40 typedef struct kobj             *kobj_t;
  41 typedef struct kobj_class       *kobj_class_t;
  42 typedef struct kobj_method      kobj_method_t;
  43 typedef int                     (*kobjop_t)(void);
  44 typedef struct kobj_ops         *kobj_ops_t;
  45 typedef struct kobjop_desc      *kobjop_desc_t;
  46 struct malloc_type;
  47
  48 struct kobj_method {
  49         kobjop_desc_t   desc;
  50         kobjop_t        func;
  51 };
  52
  53 /*
  54  * A class is simply a method table and a sizeof value. When the first
  55  * instance of the class is created, the method table will be compiled
  56  * into a form more suited to efficient method dispatch. This compiled
  57  * method table is always the first field of the object.
  58  */
  59 #define KOBJ_CLASS_FIELDS                                               \
  60         const char      *name;          /* class name */                \
  61         kobj_method_t   *methods;       /* method table */              \
  62         size_t          size;           /* object size */               \
  63         kobj_class_t    *baseclasses;   /* base classes */              \
  64         u_int           refs;           /* reference count */           \
  65         kobj_ops_t      ops             /* compiled method table */
  66
  67 struct kobj_class {
  68         KOBJ_CLASS_FIELDS;
  69 };
  70
  71 /*
  72  * Implementation of kobj.
  73  */
  74 #define KOBJ_FIELDS                             \
  75         kobj_ops_t      ops
  76
  77 struct kobj {
  78         KOBJ_FIELDS;
  79 };
  80
  81 /*
  82  * The ops table is used as a cache of results from kobj_lookup_method().
  83  */
  84
  85 #define KOBJ_CACHE_SIZE 256
  86
  87 struct kobj_ops {
  88         kobj_method_t   *cache[KOBJ_CACHE_SIZE];
  89         kobj_class_t    cls;
  90 };
  91
  92 struct kobjop_desc {
  93         unsigned int    id;     /* unique ID */
  94         kobj_method_t   *deflt; /* default implementation */
  95 };
  96
  97 /*
  98  * Shorthand for constructing method tables.
  99  */
 100 #define KOBJMETHOD(NAME, FUNC) { &NAME##_desc, (kobjop_t) FUNC }
 101
 102 /*
 103  * Declare a class (which should be defined in another file.
 104  */
 105 #define DECLARE_CLASS(name) extern struct kobj_class name
 106
 107 /*
 108  * Define a class with no base classes (api backward-compatible. with
 109  * FreeBSD-5.1 and earlier).
 110  */
 111 #define DEFINE_CLASS(name, methods, size)               \
 112 DEFINE_CLASS_0(name, name ## _class, methods, size)
 113
 114 /*
 115  * Define a class with no base classes. Use like this:
 116  *
 117  * DEFINE_CLASS_0(foo, foo_class, foo_methods, sizeof(foo_softc));
 118  */
 119 #define DEFINE_CLASS_0(name, classvar, methods, size)   \
 120                                                         \
 121 struct kobj_class classvar = {                          \
 122         #name, methods, size, NULL, 0, NULL             \
 123 }
 124
 125 /*
 126  * Define a class inheriting a single base class. Use like this:
 127  *
 128  * DEFINE_CLASS1(foo, foo_class, foo_methods, sizeof(foo_softc),
 129  *                        bar);
 130  */
 131 #define DEFINE_CLASS_1(name, classvar, methods, size,   \
 132                        base1)                           \
 133                                                         \
 134 static kobj_class_t name ## _baseclasses[] = {          \
 135         &base1, 0                                       \
 136 };                                                      \
 137 struct kobj_class classvar = {                          \
 138         #name, methods, size, name ## _baseclasses      \
 139 }
 140
 141 /*
 142  * Define a class inheriting two base classes. Use like this:
 143  *
 144  * DEFINE_CLASS2(foo, foo_class, foo_methods, sizeof(foo_softc),
 145  *                        bar, baz);
 146  */
 147 #define DEFINE_CLASS_2(name, methods, size,             \
 148                        base1, base2)                    \
 149                                                         \
 150 static kobj_class_t name ## _baseclasses[] = {          \
 151         &base1,                                         \
 152         &base2, 0                                       \
 153 };                                                      \
 154 struct kobj_class name ## _class = {                    \
 155         #name, methods, size, name ## _baseclasses      \
 156 }
 157
 158 /*
 159  * Define a class inheriting three base classes. Use like this:
 160  *
 161  * DEFINE_CLASS3(foo, foo_class, foo_methods, sizeof(foo_softc),
 162  *                        bar, baz, foobar);
 163  */
 164 #define DEFINE_CLASS_3(name, methods, size,             \
 165                        base1, base2, base3)             \
 166                                                         \
 167 static kobj_class_t name ## _baseclasses[] = {          \
 168         &base1,                                         \
 169         &base2,                                         \
 170         &base3, 0                                       \
 171 };                                                      \
 172 struct kobj_class name ## _class = {                    \
 173         #name, methods, size, name ## _baseclasses      \
 174 }
 175
 176 #ifdef _KERNEL
 177
 178 /*
 179  * Compile class for the first instance and add a reference.
 180  */
 181 void            kobj_class_instantiate(kobj_class_t cls);
 182
 183 /*
 184  * Remove a reference and free method table with the last instance.
 185  */
 186 void            kobj_class_uninstantiate(kobj_class_t cls);
 187
 188 /*
 189  * Allocate memory for and initialise a new object.
 190  */
 191 kobj_t          kobj_create(kobj_class_t cls,
 192                             struct malloc_type *mtype,
 193                             int mflags);
 194
 195 /*
 196  * Initialise a pre-allocated object.
 197  */
 198 void            kobj_init(kobj_t obj, kobj_class_t cls);
 199
 200 /*
 201  * Delete an object. If mtype is non-zero, free the memory.
 202  */
 203 void            kobj_delete(kobj_t obj, struct malloc_type *mtype);
 204
 205 /*
 206  * Maintain stats on hits/misses in lookup caches.
 207  */
 208 #ifdef KOBJ_STATS
 209 extern u_int kobj_lookup_hits;
 210 extern u_int kobj_lookup_misses;
 211 #endif
 212
 213 /*
 214  * Lookup the method in the cache and if it isn't there look it up the
 215  * slow way.
 216  */
 217 #ifdef KOBJ_STATS
 218 #define KOBJOPLOOKUP(OPS,OP) do {                                       \
 219         kobjop_desc_t _desc = &OP##_##desc;                             \
 220         kobj_method_t **_cep =                                          \
 221             &OPS->cache[_desc->id & (KOBJ_CACHE_SIZE-1)];               \
 222         kobj_method_t *_ce = *_cep;                                     \
 223         kobj_lookup_hits++; /* assume hit */                            \
 224         if (_ce->desc != _desc)                                         \
 225                 _ce = kobj_lookup_method(OPS->cls,                      \
 226                                          _cep, _desc);                  \
 227         _m = _ce->func;                                                 \
 228 } while(0)
 229 #else
 230 #define KOBJOPLOOKUP(OPS,OP) do {                                       \
 231         kobjop_desc_t _desc = &OP##_##desc;                             \
 232         kobj_method_t **_cep =                                          \
 233             &OPS->cache[_desc->id & (KOBJ_CACHE_SIZE-1)];               \
 234         kobj_method_t *_ce = *_cep;                                     \
 235         if (_ce->desc != _desc)                                         \
 236                 _ce = kobj_lookup_method(OPS->cls,                      \
 237                                          _cep, _desc);                  \
 238         _m = _ce->func;                                                 \
 239 } while(0)
 240 #endif
 241
 242 kobj_method_t *kobj_lookup_method(kobj_class_t cls,
 243                                   kobj_method_t **cep,
 244                                   kobjop_desc_t desc);
 245
 246 /*
 247  * Default method implementation. Returns ENXIO.
 248  */
 249 int kobj_error_method(void);
 250
 251 #endif /* _KERNEL */
 252
 253 #endif /* !_SYS_KOBJ_H_ */