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1f1d88f5 MW |
1 | /* -*-c-*- |
2 | * | |
3 | * Sensible Object Design header file | |
4 | * | |
5 | * (c) 2009 Straylight/Edgeware | |
6 | */ | |
7 | ||
8 | /*----- Licensing notice --------------------------------------------------* | |
9 | * | |
e0808c47 | 10 | * This file is part of the Sensible Object Design, an object system for C. |
1f1d88f5 | 11 | * |
7d21069e MW |
12 | * The SOD Runtime Library is free software; you can redistribute it and/or |
13 | * modify it under the terms of the GNU Library General Public License as | |
14 | * published by the Free Software Foundation; either version 2 of the | |
15 | * License, or (at your option) any later version. | |
1f1d88f5 | 16 | * |
7d21069e | 17 | * The SOD Runtime is distributed in the hope that it will be useful, |
1f1d88f5 MW |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
7d21069e | 20 | * GNU Library General Public License for more details. |
1f1d88f5 | 21 | * |
7d21069e MW |
22 | * You should have received a copy of the GNU Library General Public |
23 | * License along with SOD; if not, write to the Free | |
24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, | |
25 | * MA 02111-1307, USA. | |
1f1d88f5 MW |
26 | */ |
27 | ||
28 | #ifndef SOD_H | |
29 | #define SOD_H | |
30 | ||
31 | #ifdef __cplusplus | |
32 | extern "C" { | |
33 | #endif | |
34 | ||
68a4f8c9 MW |
35 | /*----- Preliminary utilities ---------------------------------------------*/ |
36 | ||
8c2c58ae MW |
37 | /* Various hacks for checking compiler versions. */ |
38 | #define SOD__GCC_P(maj, min) \ | |
39 | (__GNUC__ > (maj) || (__GNUC__ == (maj) && __GNUC_MINOR__ >= (min))) | |
40 | ||
41 | #ifdef __GNUC__ | |
42 | # define SOD__EXTENSION __extension__ | |
43 | #else | |
44 | # define SOD__EXTENSION | |
45 | #endif | |
46 | ||
e674612e MW |
47 | /* --- @SOD__HAVE_VARARGS_MACROS@ --- * |
48 | * | |
49 | * Use: Defined if the compiler supports C99-style variadic macros. | |
50 | * | |
51 | * This is more complicated than just checking the value of | |
52 | * @__STDC_VERSION__@ because GCC has traditionally claimed C89 | |
53 | * by default, but provides the functionality anyway unless it's | |
54 | * been explicitly turned off. | |
55 | */ | |
56 | ||
57 | #if __STDC_VERSION__ >= 199901 | |
58 | /* The feature exists. All is well with the world. */ | |
59 | ||
60 | # define SOD__HAVE_VARARGS_MACROS | |
61 | ||
8c2c58ae | 62 | #elif SOD__GCC_P(3, 0) |
e674612e MW |
63 | /* We're using GCC, which is trying to deny it but we don't believe it. |
64 | * Unfortunately there's a fly in the ointment: if `-pedantic' -- or, | |
65 | * worse, `-pedantic-errors' -- is set, then GCC will warn about these | |
66 | * macros being defined, and there isn't a way to detect pedantry from the | |
67 | * preprocessor. | |
68 | * | |
69 | * We must deploy bodges. There doesn't seem to be a good way to suppress | |
70 | * particular warnings from the preprocessor: in particular, messing about | |
71 | * with `pragma GCC diagnostic' doesn't help. So we're left with this | |
72 | * hack: just declare all Sod-generated header files which try to do | |
73 | * varargs macro things to be `system headers', which means that GCC's | |
74 | * preprocessor will let them get away with all manner of nefarious stuff. | |
75 | */ | |
76 | ||
77 | # define SOD__HAVE_VARARGS_MACROS | |
78 | # define SOD__VARARGS_MACROS_PREAMBLE _Pragma("GCC system_header") | |
79 | ||
80 | #endif | |
81 | ||
82 | /* Make sure this gratuitous hack is understood, at least vacuously. */ | |
83 | #ifndef SOD__VARARGS_MACROS_PREAMBLE | |
84 | # define SOD__VARARGS_MACROS_PREAMBLE | |
85 | #endif | |
86 | ||
87 | /* We're going to want to make use of this ourselves. */ | |
88 | SOD__VARARGS_MACROS_PREAMBLE | |
89 | ||
8c2c58ae MW |
90 | /* --- @SOD__ALIGNOF@ --- * |
91 | * | |
92 | * Arguments: @type@ = a C type name, consisting of declaration specifiers | |
93 | * and `*[QUALIFIERS]' declarator operators | |
94 | * | |
95 | * Returns: A sufficient alignment for objects of the given @type@, as a | |
96 | * @size_t@. | |
97 | */ | |
98 | ||
99 | #if __STDC_VERSION__ >= 201112 | |
100 | # define SOD__ALIGNOF(type) _Alignof(type) | |
101 | #elif SOD__GCC_P(4, 7) | |
102 | # define SOD__ALIGNOF(type) __extension__ _Alignof(type) | |
103 | #elif defined(__GNUC__) | |
104 | # define SOD__ALIGNOF(type) __alignof__(type) | |
105 | #else | |
106 | # define SOD__ALIGNOF(type) \ | |
adf12ca9 | 107 | offsetof(struct { char sod__x; type sod__y; }, sod__y) |
8c2c58ae MW |
108 | #endif |
109 | ||
a42893dd MW |
110 | /* --- @SOD__IGNORE@ --- * |
111 | * | |
112 | * Arguments: @var@ = some variable name | |
113 | * | |
114 | * Use: Suppress any warning that @var@ isn't used. | |
115 | */ | |
116 | ||
117 | #define SOD__IGNORE(var) ((void)(var)) | |
118 | ||
3b7437bc MW |
119 | /* --- @SOD__NORETURN@ --- * |
120 | * | |
121 | * Use: Marks functions which are not expected to return. | |
122 | */ | |
123 | ||
124 | #if SOD__GCC_P(2, 5) | |
125 | # define SOD__NORETURN __attribute__((__noreturn__)) | |
126 | #endif | |
127 | ||
128 | #ifndef SOD__NORETURN | |
129 | # define SOD__NORETURN | |
130 | #endif | |
131 | ||
558e70ee MW |
132 | /* --- @SOD__PARANOIA@ --- * |
133 | * | |
134 | * Arguments: @cond@ = a condition to check | |
135 | * @conseq@ = a thing to evaluate to if the check passes | |
136 | * @alt@ = a thing to do if the check fails | |
137 | * | |
138 | * Use: Check to make sure something is good at runtime, unless | |
139 | * disabled. | |
140 | */ | |
141 | ||
142 | #if SOD_RECKLESS | |
143 | # define SOD__PARANOIA(cond, conseq, alt) (conseq) | |
144 | #else | |
145 | # define SOD__PARANOIA(cond, conseq, alt) ((cond) ? (conseq) : (alt)) | |
146 | #endif | |
147 | ||
68a4f8c9 MW |
148 | /* --- @SOD__CAR@ --- * |
149 | * | |
150 | * Arguments: @...@ = a nonempty list of arguments | |
151 | * | |
152 | * Returns: The first argument only. | |
153 | */ | |
154 | ||
e674612e | 155 | #ifdef SOD__HAVE_VARARGS_MACROS |
91116f94 | 156 | # define SOD__CAR(...) SOD__CARx(__VA_ARGS__, _) |
68a4f8c9 MW |
157 | # define SOD__CARx(a, ...) a |
158 | #endif | |
159 | ||
1f1d88f5 MW |
160 | /*----- Header files ------------------------------------------------------*/ |
161 | ||
162 | #include <stdarg.h> | |
163 | #include <stddef.h> | |
164 | ||
9e91c8e7 | 165 | #include "keyword.h" |
ddee4bb1 | 166 | #include "sod-base.h" |
1f1d88f5 MW |
167 | |
168 | /*----- Data structures ---------------------------------------------------*/ | |
169 | ||
170 | /* A skeletal vtable structure. At the beginning of every ichain is a | |
171 | * pointer to one of these. | |
172 | */ | |
173 | struct sod_vtable { | |
dea4d055 | 174 | const SodClass *_class; /* Pointer to class object */ |
1f1d88f5 MW |
175 | size_t _base; /* Offset to instance base */ |
176 | }; | |
177 | ||
178 | /* A skeletal instance structure. Every instance pointer points to one of | |
179 | * these. | |
180 | */ | |
181 | struct sod_instance { | |
d83a91c6 | 182 | const struct sod_vtable *_vt; /* Pointer to (chain's) vtable */ |
1f1d88f5 MW |
183 | }; |
184 | ||
185 | /* Information about a particular chain of superclasses. In each class, | |
186 | * there's a pointer to an array of these. If you search hard enough, you'll | |
187 | * be able to find out a fair amount of information about an instance and its | |
188 | * class. | |
189 | */ | |
190 | struct sod_chain { | |
191 | size_t n_classes; /* Number of classes in chain */ | |
192 | const SodClass *const *classes; /* Vector of classes, head first */ | |
193 | size_t off_ichain; /* Offset of ichain from base */ | |
194 | const struct sod_vtable *vt; /* Chain's vtable pointer */ | |
195 | size_t ichainsz; /* Size of the ichain structure */ | |
196 | }; | |
197 | ||
198 | /*----- Infrastructure macros ---------------------------------------------*/ | |
199 | ||
200 | /* --- @SOD_XCHAIN@ --- * | |
201 | * | |
202 | * Arguments: @chead@ = nickname of target chain's head | |
6a590fd0 | 203 | * @obj@ = pointer to an instance chain |
1f1d88f5 | 204 | * |
664b3951 | 205 | * Returns: Pointer to target chain, as a @void *@. |
1f1d88f5 MW |
206 | * |
207 | * Use: Utility for implementing cross-chain upcasts. It's probably | |
208 | * not that clever to use this macro directly; it's used to make | |
209 | * the automatically-generated upcast macros more palatable. | |
210 | */ | |
211 | ||
664b3951 MW |
212 | #define SOD_XCHAIN(chead, obj) \ |
213 | ((void *)((char *)(obj) + (obj)->_vt->_off_##chead)) | |
1f1d88f5 | 214 | |
a07d8d00 MW |
215 | /* --- @SOD_OFFSETDIFF@ --- * |
216 | * | |
217 | * Arguments: @type@ = a simple (i.e., declaratorless) type name | |
218 | * @mema, memb@ = members of @type@ | |
219 | * | |
220 | * Returns: The relative offset from @mema@ to @memb@, as a @ptrdiff_t@. | |
221 | * | |
222 | * Use: Computes a signed offset between structure members. | |
223 | */ | |
224 | ||
225 | #define SOD_OFFSETDIFF(type, mema, memb) \ | |
226 | ((ptrdiff_t)offsetof(type, memb) - (ptrdiff_t)offsetof(type, mema)) | |
227 | ||
1f1d88f5 MW |
228 | /* --- @SOD_ILAYOUT@ --- * |
229 | * | |
230 | * Arguments: @cls@ = name of a class | |
231 | * @chead@ = nickname of chain head of @cls@ | |
6a590fd0 MW |
232 | * @obj@ = pointer to the @chead@ ichain of an (exact) instance |
233 | * of @cls@ | |
1f1d88f5 MW |
234 | * |
235 | * Returns: A pointer to the instance's base, cast as a pointer to the | |
236 | * ilayout structure. | |
237 | * | |
238 | * Use: Finds an instance's base address given a pointer to one of | |
239 | * its ichains, if you know precisely the instance's class and | |
45c53484 MW |
240 | * which chain you're pointing to. If you don't, then (a) you |
241 | * want @SOD_INSTBASE@ below, and (b) you'll have the wrong | |
1f1d88f5 MW |
242 | * ilayout anyway. |
243 | * | |
244 | * This macro is not intended to be used directly outside of | |
245 | * automatically generated effective method and trampoline | |
246 | * functions, which have the kinds of specific knowledge | |
247 | * necessary to use it safely. | |
248 | */ | |
249 | ||
6a590fd0 | 250 | #define SOD_ILAYOUT(cls, chead, obj) \ |
1f1d88f5 | 251 | ((struct cls##__ilayout *) \ |
6a590fd0 MW |
252 | ((char *)(obj) - offsetof(struct cls##__ilayout, chead))) |
253 | ||
254 | /*----- Utility macros ----------------------------------------------------*/ | |
255 | ||
256 | /* --- @SOD_CLASSOF@ --- * | |
257 | * | |
258 | * Arguments: @p@ = pointer to an instance chain | |
259 | * | |
cb9f1e5e | 260 | * Returns: A pointer to the instance's class, as a @const SodClass *@. |
6a590fd0 MW |
261 | */ |
262 | ||
263 | #define SOD_CLASSOF(obj) ((const SodClass *)(obj)->_vt->_class) | |
1f1d88f5 | 264 | |
45c53484 MW |
265 | /* --- @SOD_INSTBASE@ --- * |
266 | * | |
6a590fd0 MW |
267 | * Arguments: @obj@ = pointer to an instance (i.e., the address of one of |
268 | * its instance chains) | |
45c53484 | 269 | * |
6a590fd0 | 270 | * Returns: The base address of @obj@'s instance layout, as a @void *@. |
45c53484 MW |
271 | * |
272 | * Use: Finds the base address of an instance. If you know the | |
273 | * dynamic class of the object then @SOD_ILAYOUT@ is faster. If | |
274 | * you don't, this is the right macro, but your options for | |
275 | * doing something sensible with the result are limited, mostly | |
276 | * to simple memory management operations such as freeing or | |
277 | * zeroizing the instance structure. | |
278 | */ | |
279 | ||
6a590fd0 | 280 | #define SOD_INSTBASE(obj) ((void *)((char *)(obj) - (obj)->_vt->_base)) |
77027cca | 281 | |
6a590fd0 | 282 | /* --- @SOD_CONVERT@ --- * |
77027cca | 283 | * |
6a590fd0 MW |
284 | * Arguments: @cls@ = a class type name |
285 | * @const void *obj@ = a pointer to an instance | |
77027cca | 286 | * |
6a590fd0 MW |
287 | * Returns: Pointer to appropriate instance ichain, or null if the |
288 | * instance isn't of the specified class. | |
289 | * | |
290 | * Use: This is a simple wrapper around the @sod_convert@, which | |
291 | * you should see for full details. It accepts a class type | |
292 | * name rather than a pointer to a class object, and arranges to | |
293 | * return a pointer of the correct type. | |
77027cca MW |
294 | */ |
295 | ||
6a590fd0 | 296 | #define SOD_CONVERT(cls, obj) ((cls *)sod_convert(cls##__class, (obj))) |
77027cca | 297 | |
a142609c MW |
298 | /* --- @SOD_INIT@ --- * |
299 | * | |
300 | * Arguments: @cls@ = a class type name | |
301 | * @p@ = pointer to storage to initialize | |
302 | * @keys@ = a @KWARGS(...)@ keyword argument sequence | |
303 | * | |
304 | * Use: Initializes raw storage as an instance of @cls@. | |
305 | */ | |
306 | ||
307 | #define SOD_INIT(cls, p, keys) ((cls *)sod_init(cls##__class, (p), keys)) | |
308 | ||
a42893dd MW |
309 | /* --- @SOD_MAKE@ --- * |
310 | * | |
311 | * Arguments: @cls@ = a class type name | |
312 | * @keys@ = a @KWARGS(...)@ keyword argument sequence | |
313 | * | |
314 | * Use: Allocates (using @malloc@) eand initializes storage to be an | |
315 | * instance of @cls@. Returns a null pointer if allocation | |
316 | * fails. Use @sod_destroy@ to release the instance. | |
317 | */ | |
318 | ||
319 | #define SOD_MAKE(cls, keys) ((cls *)sod_make(cls##__class, keys)) | |
320 | ||
267dd3e7 MW |
321 | /* --- @SOD_DECL@ --- * |
322 | * | |
3b7437bc | 323 | * Arguments: @cls_@ = a class type name |
a142609c MW |
324 | * @var@ = a variable name |
325 | * @keys@ = a @KWARGS(...)@ keyword argument sequence | |
267dd3e7 | 326 | * |
a142609c MW |
327 | * Use: Declare @var@ as a pointer to an initialized instance of |
328 | * @cls@ with automatic lifetime. | |
267dd3e7 MW |
329 | */ |
330 | ||
3b7437bc MW |
331 | #define SOD_DECL(cls_, var, keys) \ |
332 | struct cls_##__ilayout var##__layout; \ | |
333 | cls_ *var = \ | |
334 | SOD__PARANOIA(sizeof(var##__layout) == cls_##__class->cls.initsz, \ | |
335 | (cls_ *)sod_init(cls_##__class, &var##__layout, keys), \ | |
336 | (sod__chksz_fail(cls_##__class, sizeof(var##__layout)), \ | |
337 | (cls_ *)0)) | |
267dd3e7 | 338 | |
1f1d88f5 MW |
339 | /*----- Functions provided ------------------------------------------------*/ |
340 | ||
3b7437bc MW |
341 | /* --- @sod__chksz_fail@ --- * |
342 | * | |
343 | * Arguments: @const SodClass *cls@ = class we were trying to instantiate | |
344 | * @size_t sz@ = size allocated | |
345 | * | |
346 | * Returns: Doesn't. | |
347 | * | |
348 | * Use: Reports instantiation failure caused by a mismatch between | |
349 | * the size allocated (@sz@) and the size required for an | |
350 | * instance of class @cls@. | |
351 | */ | |
352 | ||
353 | extern SOD__NORETURN | |
354 | void sod__chksz_fail(const SodClass */*cls*/, size_t /*sz*/); | |
355 | ||
77027cca MW |
356 | /* --- @sod_subclassp@ --- * |
357 | * | |
dea4d055 | 358 | * Arguments: @const SodClass *sub, *super@ = pointers to two classes |
77027cca MW |
359 | * |
360 | * Returns: Nonzero if @c@ is a subclass of @d@. | |
361 | */ | |
362 | ||
dea4d055 | 363 | extern int sod_subclassp(const SodClass */*sub*/, const SodClass */*super*/); |
77027cca | 364 | |
1f1d88f5 MW |
365 | /* --- @sod_convert@ --- * |
366 | * | |
367 | * Arguments: @const SodClass *cls@ = desired class object | |
368 | * @const void *obj@ = pointer to instance | |
369 | * | |
370 | * Returns: Pointer to appropriate ichain of object, or null if the | |
371 | * instance isn't of the specified class. | |
372 | * | |
373 | * Use: General down/cross-casting function. | |
374 | * | |
375 | * Upcasts can be performed efficiently using the automatically | |
dea4d055 | 376 | * generated macros. In particular, upcasts within a chain are |
1f1d88f5 MW |
377 | * trivial; cross-chain upcasts require information from vtables |
378 | * but are fairly fast. This function is rather slower, but is | |
379 | * much more general. | |
380 | * | |
381 | * Suppose we have an instance of a class C, referred to by a | |
dea4d055 | 382 | * pointer to an instance of one of C's superclasses S. If T |
1f1d88f5 | 383 | * is some other superclass of C then this function will return |
dea4d055 | 384 | * a pointer to C suitable for use as an instance of T. If T |
1f1d88f5 MW |
385 | * is not a superclass of C, then the function returns null. |
386 | * (If the pointer doesn't point to an instance of some class | |
387 | * then the behaviour is undefined.) Note that you don't need | |
dea4d055 | 388 | * to know what either C or S actually are. |
1f1d88f5 MW |
389 | */ |
390 | ||
6a590fd0 | 391 | extern void *sod_convert(const SodClass */*cls*/, const void */*obj*/); |
1f1d88f5 | 392 | |
a142609c MW |
393 | /* --- @sod_init@, @sod_initv@ --- * |
394 | * | |
395 | * Arguments: @const SodClass *cls@ = class object for new instance | |
396 | * @void *p@ = pointer to storage for new instance | |
397 | * @va_list ap, ...@ = initialization keyword arguments | |
398 | * | |
399 | * Returns: Pointer to the initialized instance. | |
400 | * | |
401 | * Use: Initializes an instance in pre-allocated storage, and returns | |
402 | * a pointer to it. | |
403 | * | |
404 | * This function will imprint the storage, and then send an | |
405 | * `initialize' message to the fresh instance containing the | |
406 | * provided keyword arguments. | |
407 | * | |
408 | * It's usually convenient to use the macro @SOD_INIT@ rather | |
409 | * than calling @sod_init@ directly. | |
410 | */ | |
411 | ||
412 | extern KWCALL void *sod_init(const SodClass */*cls*/, void */*p*/, ...); | |
413 | extern void *sod_initv(const SodClass */*cls*/, void */*p*/, va_list /*ap*/); | |
414 | ||
a42893dd MW |
415 | /* --- @sod_make@, @sod_makev@ --- * |
416 | * | |
417 | * Arguments: @const SodClass *cls@ = class object for new instance | |
418 | * @va_list ap, ...@ = initialization keyword arguments | |
419 | * | |
420 | * Returns: Pointer to the newly-allocated initialized instance, or null. | |
421 | * | |
422 | * Use: Allocates storage for a new instance, initializes it, and | |
423 | * returns a pointer to it. If allocation fails, a null pointer | |
424 | * is returned instead. | |
425 | * | |
426 | * This function will allocate the storage using @malloc@, and | |
427 | * then initialize it as for @sod_init@. | |
428 | * | |
429 | * It's usually convenient to use the macro @SOD_MAKE@ rather | |
430 | * than calling @sod_make@ directly. | |
431 | * | |
432 | * (This function is not available in freestanding environments | |
433 | * lacking @malloc@ and @free@.) | |
434 | */ | |
435 | ||
436 | extern KWCALL void *sod_make(const SodClass */*cls*/, ...); | |
437 | extern void *sod_makev(const SodClass */*cls*/, va_list /*ap*/); | |
438 | ||
439 | /* --- @sod_teardown@ --- * | |
440 | * | |
441 | * Arguments: @void *p@ = pointer to an instance to be torn down | |
442 | * | |
443 | * Returns: Zero if the object is torn down; nonzero if it refused for | |
444 | * some reason. | |
445 | * | |
446 | * Use: Invokes the instance's `teardown' method to release any held | |
447 | * resources. | |
448 | * | |
449 | * If this function returns nonzero, then the object is still | |
450 | * active, and may still hold important resources. This is not | |
451 | * intended to be a failure condition: failures in teardown are | |
452 | * usually unrecoverable (or very hard to recover from) and | |
453 | * should probably cause the program to abort. A refusal, on | |
454 | * the other hand, means that the object is still live and | |
455 | * shouldn't be deallocated, but that this is a normal situation | |
456 | * and the caller shouldn't worry about it. | |
457 | */ | |
458 | ||
459 | extern int sod_teardown(void */*p*/); | |
460 | ||
461 | /* --- @sod_destroy@ --- * | |
462 | * | |
463 | * Arguments: @void *p@ = pointer to an instance to be torn down, or null | |
464 | * | |
465 | * Returns: Zero if the object was freed; nonzero if it refused for some | |
466 | * reason. | |
467 | * | |
468 | * Use: Invokes the instance's `teardown' method to release any held | |
469 | * resources, and then calls @free@ to release the instance's | |
470 | * storage. See @sod_teardown@ for details, especially | |
471 | * regarding the return value's meaning. | |
472 | * | |
473 | * If @p@ is null, then this function does nothing except | |
474 | * returns zero. | |
475 | * | |
476 | * (This function is not available in freestanding environments | |
477 | * lacking @malloc@ and @free@.) | |
478 | */ | |
479 | ||
480 | extern int sod_destroy(void */*p*/); | |
481 | ||
1f1d88f5 MW |
482 | /*----- That's all, folks -------------------------------------------------*/ |
483 | ||
484 | #ifdef __cplusplus | |
485 | } | |
486 | #endif | |
487 | ||
488 | #endif |