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1 | /* GNU Objective C Runtime protocol related functions. | |
2 | Copyright (C) 2010-2024 Free Software Foundation, Inc. | |
3 | Contributed by Nicola Pero | |
4 | ||
5 | This file is part of GCC. | |
6 | ||
7 | GCC is free software; you can redistribute it and/or modify it under the | |
8 | terms of the GNU General Public License as published by the Free Software | |
9 | Foundation; either version 3, or (at your option) any later version. | |
10 | ||
11 | GCC is distributed in the hope that it will be useful, but WITHOUT ANY | |
12 | WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS | |
13 | FOR A PARTICULAR PURPOSE. See the GNU General Public License for more | |
14 | details. | |
15 | ||
16 | Under Section 7 of GPL version 3, you are granted additional | |
17 | permissions described in the GCC Runtime Library Exception, version | |
18 | 3.1, as published by the Free Software Foundation. | |
19 | ||
20 | You should have received a copy of the GNU General Public License and | |
21 | a copy of the GCC Runtime Library Exception along with this program; | |
22 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
23 | <http://www.gnu.org/licenses/>. */ | |
24 | ||
25 | #include "objc-private/common.h" | |
26 | #include "objc/runtime.h" | |
27 | #include "objc-private/module-abi-8.h" /* For runtime structures */ | |
28 | #include "objc/thr.h" | |
29 | #include "objc-private/runtime.h" /* the kitchen sink */ | |
30 | #include "objc-private/hash.h" /* For the hash table of protocols. */ | |
31 | #include "objc-private/protocols.h" /* For __objc_protocols_init() and | |
32 | __objc_protocols_add_protocol(). */ | |
33 | #include <stdlib.h> /* For malloc. */ | |
34 | ||
35 | /* This is a table that maps a name to a Protocol instance with that | |
36 | name. Because there may be multiple Protocol instances with the | |
37 | same name (no harm in that) the table records only one | |
38 | instance. */ | |
39 | static cache_ptr __protocols_hashtable; | |
40 | ||
41 | /* A mutex protecting the protocol_hashtable. */ | |
42 | static objc_mutex_t __protocols_hashtable_lock = NULL; | |
43 | ||
44 | /* Called at startup by init.c. */ | |
45 | void | |
46 | __objc_protocols_init (void) | |
47 | { | |
48 | __protocols_hashtable_lock = objc_mutex_allocate (); | |
49 | ||
50 | /* The keys in the table are strings, and the values are Protocol | |
51 | objects. */ | |
52 | __protocols_hashtable = objc_hash_new (64, (hash_func_type) objc_hash_string, | |
53 | (compare_func_type) objc_compare_strings); | |
54 | } | |
55 | ||
56 | /* Add a protocol to the hashtable. */ | |
57 | void | |
58 | __objc_protocols_add_protocol (const char *name, struct objc_protocol *object) | |
59 | { | |
60 | objc_mutex_lock (__protocols_hashtable_lock); | |
61 | ||
62 | /* If we find a protocol with the same name already in the | |
63 | hashtable, we do not need to add the new one, because it will be | |
64 | identical to it. This in the reasonable assumption that two | |
65 | protocols with the same name are identical, which is expected in | |
66 | any sane program. If we are really paranoid, we would compare | |
67 | the protocols and abort if they are not identical. | |
68 | Unfortunately, this would slow down the startup of all | |
69 | Objective-C programs while trying to catch a problem that has | |
70 | never been seen in practice, so we don't do it. */ | |
71 | if (! objc_hash_is_key_in_hash (__protocols_hashtable, name)) | |
72 | objc_hash_add (&__protocols_hashtable, name, object); | |
73 | ||
74 | objc_mutex_unlock (__protocols_hashtable_lock); | |
75 | } | |
76 | ||
77 | Protocol * | |
78 | objc_getProtocol (const char *name) | |
79 | { | |
80 | Protocol *protocol; | |
81 | ||
82 | if (name == NULL) | |
83 | return NULL; | |
84 | ||
85 | objc_mutex_lock (__protocols_hashtable_lock); | |
86 | protocol = (Protocol *)(objc_hash_value_for_key (__protocols_hashtable, name)); | |
87 | objc_mutex_unlock (__protocols_hashtable_lock); | |
88 | ||
89 | return protocol; | |
90 | } | |
91 | ||
92 | Protocol ** | |
93 | objc_copyProtocolList (unsigned int *numberOfReturnedProtocols) | |
94 | { | |
95 | unsigned int count = 0; | |
96 | Protocol **returnValue = NULL; | |
97 | node_ptr node; | |
98 | ||
99 | objc_mutex_lock (__protocols_hashtable_lock); | |
100 | ||
101 | /* Count how many protocols we have. */ | |
102 | node = objc_hash_next (__protocols_hashtable, NULL); | |
103 | while (node) | |
104 | { | |
105 | count++; | |
106 | node = objc_hash_next (__protocols_hashtable, node); | |
107 | } | |
108 | ||
109 | if (count != 0) | |
110 | { | |
111 | unsigned int i = 0; | |
112 | ||
113 | /* Allocate enough memory to hold them. */ | |
114 | returnValue = (Protocol **)(malloc (sizeof (Protocol *) * (count + 1))); | |
115 | ||
116 | /* Copy the protocols. */ | |
117 | node = objc_hash_next (__protocols_hashtable, NULL); | |
118 | while (node) | |
119 | { | |
120 | returnValue[i] = node->value; | |
121 | i++; | |
122 | node = objc_hash_next (__protocols_hashtable, node); | |
123 | } | |
124 | ||
125 | returnValue[i] = NULL; | |
126 | } | |
127 | objc_mutex_unlock (__protocols_hashtable_lock); | |
128 | ||
129 | if (numberOfReturnedProtocols) | |
130 | *numberOfReturnedProtocols = count; | |
131 | ||
132 | return returnValue; | |
133 | } | |
134 | ||
135 | BOOL | |
136 | class_addProtocol (Class class_, Protocol *protocol) | |
137 | { | |
138 | struct objc_protocol_list *protocols; | |
139 | ||
140 | if (class_ == Nil || protocol == NULL) | |
141 | return NO; | |
142 | ||
143 | if (class_conformsToProtocol (class_, protocol)) | |
144 | return NO; | |
145 | ||
146 | /* Check that it is a Protocol object before casting it to (struct | |
147 | objc_protocol *). */ | |
148 | if (protocol->class_pointer != objc_lookUpClass ("Protocol")) | |
149 | return NO; | |
150 | ||
151 | objc_mutex_lock (__objc_runtime_mutex); | |
152 | ||
153 | /* Create the objc_protocol_list. */ | |
154 | protocols = malloc (sizeof (struct objc_protocol_list)); | |
155 | protocols->count = 1; | |
156 | protocols->list[0] = (struct objc_protocol *)protocol; | |
157 | ||
158 | /* Attach it to the list of class protocols. */ | |
159 | protocols->next = class_->protocols; | |
160 | class_->protocols = protocols; | |
161 | ||
162 | objc_mutex_unlock (__objc_runtime_mutex); | |
163 | ||
164 | return YES; | |
165 | } | |
166 | ||
167 | BOOL | |
168 | class_conformsToProtocol (Class class_, Protocol *protocol) | |
169 | { | |
170 | struct objc_protocol_list* proto_list; | |
171 | ||
172 | if (class_ == Nil || protocol == NULL) | |
173 | return NO; | |
174 | ||
175 | /* Check that it is a Protocol object before casting it to (struct | |
176 | objc_protocol *). */ | |
177 | if (protocol->class_pointer != objc_lookUpClass ("Protocol")) | |
178 | return NO; | |
179 | ||
180 | /* Acquire the runtime lock because the list of protocols for a | |
181 | class may be modified concurrently, for example if another thread | |
182 | calls class_addProtocol(), or dynamically loads from a file a | |
183 | category of the class. */ | |
184 | objc_mutex_lock (__objc_runtime_mutex); | |
185 | proto_list = class_->protocols; | |
186 | ||
187 | while (proto_list) | |
188 | { | |
189 | size_t i; | |
190 | for (i = 0; i < proto_list->count; i++) | |
191 | { | |
192 | if (proto_list->list[i] == (struct objc_protocol *)protocol | |
193 | || protocol_conformsToProtocol ((Protocol *)proto_list->list[i], | |
194 | protocol)) | |
195 | { | |
196 | objc_mutex_unlock (__objc_runtime_mutex); | |
197 | return YES; | |
198 | } | |
199 | } | |
200 | proto_list = proto_list->next; | |
201 | } | |
202 | ||
203 | objc_mutex_unlock (__objc_runtime_mutex); | |
204 | return NO; | |
205 | } | |
206 | ||
207 | Protocol ** | |
208 | class_copyProtocolList (Class class_, unsigned int *numberOfReturnedProtocols) | |
209 | { | |
210 | unsigned int count = 0; | |
211 | Protocol **returnValue = NULL; | |
212 | struct objc_protocol_list* proto_list; | |
213 | ||
214 | if (class_ == Nil) | |
215 | { | |
216 | if (numberOfReturnedProtocols) | |
217 | *numberOfReturnedProtocols = 0; | |
218 | return NULL; | |
219 | } | |
220 | ||
221 | /* Lock the runtime mutex because the class protocols may be | |
222 | concurrently modified. */ | |
223 | objc_mutex_lock (__objc_runtime_mutex); | |
224 | ||
225 | /* Count how many protocols we have. */ | |
226 | proto_list = class_->protocols; | |
227 | ||
228 | while (proto_list) | |
229 | { | |
230 | count = count + proto_list->count; | |
231 | proto_list = proto_list->next; | |
232 | } | |
233 | ||
234 | if (count != 0) | |
235 | { | |
236 | unsigned int i = 0; | |
237 | ||
238 | /* Allocate enough memory to hold them. */ | |
239 | returnValue = (Protocol **)(malloc (sizeof (Protocol *) * (count + 1))); | |
240 | ||
241 | /* Copy the protocols. */ | |
242 | proto_list = class_->protocols; | |
243 | ||
244 | while (proto_list) | |
245 | { | |
246 | size_t j; | |
247 | for (j = 0; j < proto_list->count; j++) | |
248 | { | |
249 | returnValue[i] = (Protocol *)proto_list->list[j]; | |
250 | i++; | |
251 | } | |
252 | proto_list = proto_list->next; | |
253 | } | |
254 | ||
255 | returnValue[i] = NULL; | |
256 | } | |
257 | objc_mutex_unlock (__objc_runtime_mutex); | |
258 | ||
259 | if (numberOfReturnedProtocols) | |
260 | *numberOfReturnedProtocols = count; | |
261 | ||
262 | return returnValue; | |
263 | } | |
264 | ||
265 | BOOL | |
266 | protocol_conformsToProtocol (Protocol *protocol, Protocol *anotherProtocol) | |
267 | { | |
268 | struct objc_protocol_list* proto_list; | |
269 | ||
270 | if (protocol == NULL || anotherProtocol == NULL) | |
271 | return NO; | |
272 | ||
273 | if (protocol == anotherProtocol) | |
274 | return YES; | |
275 | ||
276 | /* Check that the objects are Protocol objects before casting them | |
277 | to (struct objc_protocol *). */ | |
278 | if (protocol->class_pointer != anotherProtocol->class_pointer) | |
279 | return NO; | |
280 | ||
281 | if (protocol->class_pointer != objc_lookUpClass ("Protocol")) | |
282 | return NO; | |
283 | ||
284 | if (strcmp (((struct objc_protocol *)protocol)->protocol_name, | |
285 | ((struct objc_protocol *)anotherProtocol)->protocol_name) == 0) | |
286 | return YES; | |
287 | ||
288 | /* We do not acquire any lock because protocols are currently | |
289 | immutable. We can freely iterate over a protocol structure. */ | |
290 | proto_list = ((struct objc_protocol *)protocol)->protocol_list; | |
291 | while (proto_list) | |
292 | { | |
293 | size_t i; | |
294 | ||
295 | for (i = 0; i < proto_list->count; i++) | |
296 | { | |
297 | if (protocol_conformsToProtocol ((Protocol *)proto_list->list[i], anotherProtocol)) | |
298 | return YES; | |
299 | } | |
300 | proto_list = proto_list->next; | |
301 | } | |
302 | ||
303 | return NO; | |
304 | } | |
305 | ||
306 | BOOL | |
307 | protocol_isEqual (Protocol *protocol, Protocol *anotherProtocol) | |
308 | { | |
309 | if (protocol == anotherProtocol) | |
310 | return YES; | |
311 | ||
312 | if (protocol == NULL || anotherProtocol == NULL) | |
313 | return NO; | |
314 | ||
315 | /* Check that the objects are Protocol objects before casting them | |
316 | to (struct objc_protocol *). */ | |
317 | if (protocol->class_pointer != anotherProtocol->class_pointer) | |
318 | return NO; | |
319 | ||
320 | if (protocol->class_pointer != objc_lookUpClass ("Protocol")) | |
321 | return NO; | |
322 | ||
323 | /* Equality between formal protocols is only formal (nothing to do | |
324 | with actually checking the list of methods they have!). Two | |
325 | formal Protocols are equal if and only if they have the same | |
326 | name. | |
327 | ||
328 | Please note (for comparisons with other implementations) that | |
329 | checking the names is equivalent to checking that Protocol A | |
330 | conforms to Protocol B and Protocol B conforms to Protocol A, | |
331 | because this happens iff they have the same name. If they have | |
332 | different names, A conforms to B if and only if A includes B, but | |
333 | the situation where A includes B and B includes A is a circular | |
334 | dependency between Protocols which is forbidden by the compiler, | |
335 | so A conforms to B and B conforms to A with A and B having | |
336 | different names is an impossible case. */ | |
337 | if (strcmp (((struct objc_protocol *)protocol)->protocol_name, | |
338 | ((struct objc_protocol *)anotherProtocol)->protocol_name) == 0) | |
339 | return YES; | |
340 | ||
341 | return NO; | |
342 | } | |
343 | ||
344 | const char * | |
345 | protocol_getName (Protocol *protocol) | |
346 | { | |
347 | /* Check that it is a Protocol object before casting it to (struct | |
348 | objc_protocol *). */ | |
349 | if (protocol->class_pointer != objc_lookUpClass ("Protocol")) | |
350 | return NULL; | |
351 | ||
352 | return ((struct objc_protocol *)protocol)->protocol_name; | |
353 | } | |
354 | ||
355 | struct objc_method_description protocol_getMethodDescription (Protocol *protocol, | |
356 | SEL selector, | |
357 | BOOL requiredMethod, | |
358 | BOOL instanceMethod) | |
359 | { | |
360 | struct objc_method_description no_result = { NULL, NULL }; | |
361 | struct objc_method_description_list *methods; | |
362 | int i; | |
363 | ||
364 | /* TODO: New ABI. */ | |
365 | /* The current ABI does not have any information on optional protocol methods. */ | |
366 | if (! requiredMethod) | |
367 | return no_result; | |
368 | ||
369 | /* Check that it is a Protocol object before casting it to (struct | |
370 | objc_protocol *). */ | |
371 | if (protocol->class_pointer != objc_lookUpClass ("Protocol")) | |
372 | return no_result; | |
373 | ||
374 | if (instanceMethod) | |
375 | methods = ((struct objc_protocol *)protocol)->instance_methods; | |
376 | else | |
377 | methods = ((struct objc_protocol *)protocol)->class_methods; | |
378 | ||
379 | if (methods) | |
380 | { | |
381 | for (i = 0; i < methods->count; i++) | |
382 | { | |
383 | if (sel_isEqual (methods->list[i].name, selector)) | |
384 | return methods->list[i]; | |
385 | /* | |
386 | if (strcmp (sel_getName (methods->list[i].name), selector_name) == 0) | |
387 | return methods->list[i]; | |
388 | */ | |
389 | } | |
390 | } | |
391 | ||
392 | return no_result; | |
393 | } | |
394 | ||
395 | struct objc_method_description *protocol_copyMethodDescriptionList (Protocol *protocol, | |
396 | BOOL requiredMethod, | |
397 | BOOL instanceMethod, | |
398 | unsigned int *numberOfReturnedMethods) | |
399 | { | |
400 | struct objc_method_description_list *methods; | |
401 | unsigned int count = 0; | |
402 | struct objc_method_description *returnValue = NULL; | |
403 | ||
404 | /* TODO: New ABI */ | |
405 | /* The current ABI does not have any information on optional protocol methods. */ | |
406 | if (! requiredMethod) | |
407 | { | |
408 | if (numberOfReturnedMethods) | |
409 | *numberOfReturnedMethods = 0; | |
410 | ||
411 | return NULL; | |
412 | } | |
413 | ||
414 | /* Check that it is a Protocol object before casting it to (struct | |
415 | objc_protocol *). */ | |
416 | if (protocol == NULL || protocol->class_pointer != objc_lookUpClass ("Protocol")) | |
417 | { | |
418 | if (numberOfReturnedMethods) | |
419 | *numberOfReturnedMethods = 0; | |
420 | ||
421 | return NULL; | |
422 | } | |
423 | ||
424 | /* We do not acquire any lock because protocols are currently | |
425 | immutable. We can freely iterate over a protocol structure. */ | |
426 | ||
427 | if (instanceMethod) | |
428 | methods = ((struct objc_protocol *)protocol)->instance_methods; | |
429 | else | |
430 | methods = ((struct objc_protocol *)protocol)->class_methods; | |
431 | ||
432 | if (methods) | |
433 | { | |
434 | unsigned int i; | |
435 | count = methods->count; | |
436 | ||
437 | /* Allocate enough memory to hold them. */ | |
438 | returnValue = (struct objc_method_description *)(malloc (sizeof (struct objc_method_description) * (count + 1))); | |
439 | ||
440 | /* Copy them. */ | |
441 | for (i = 0; i < count; i++) | |
442 | { | |
443 | returnValue[i].name = methods->list[i].name; | |
444 | returnValue[i].types = methods->list[i].types; | |
445 | } | |
446 | returnValue[i].name = NULL; | |
447 | returnValue[i].types = NULL; | |
448 | } | |
449 | ||
450 | if (numberOfReturnedMethods) | |
451 | *numberOfReturnedMethods = count; | |
452 | ||
453 | return returnValue; | |
454 | } | |
455 | ||
456 | Property protocol_getProperty (Protocol *protocol, const char *propertyName, | |
457 | BOOL requiredProperty, BOOL instanceProperty) | |
458 | { | |
459 | if (protocol == NULL || propertyName == NULL) | |
460 | return NULL; | |
461 | ||
462 | if (!requiredProperty || !instanceProperty) | |
463 | return NULL; | |
464 | ||
465 | /* Check that it is a Protocol object before casting it to (struct | |
466 | objc_protocol *). */ | |
467 | if (protocol->class_pointer != objc_lookUpClass ("Protocol")) | |
468 | return NULL; | |
469 | ||
470 | /* TODO: New ABI. */ | |
471 | /* The current ABI does not have any information on protocol properties. */ | |
472 | return NULL; | |
473 | } | |
474 | ||
475 | Property *protocol_copyPropertyList (Protocol *protocol, unsigned int *numberOfReturnedProperties) | |
476 | { | |
477 | unsigned int count = 0; | |
478 | Property *returnValue = NULL; | |
479 | ||
480 | /* Check that it is a Protocol object before casting it to (struct | |
481 | objc_protocol *). */ | |
482 | if (protocol == NULL || protocol->class_pointer != objc_lookUpClass ("Protocol")) | |
483 | { | |
484 | if (numberOfReturnedProperties) | |
485 | *numberOfReturnedProperties = 0; | |
486 | ||
487 | return NULL; | |
488 | } | |
489 | ||
490 | /* We do not acquire any lock because protocols are currently | |
491 | immutable. We can freely iterate over a protocol structure. */ | |
492 | ||
493 | /* TODO: New ABI. */ | |
494 | /* The current ABI does not have any information on protocol properties. */ | |
495 | if (numberOfReturnedProperties) | |
496 | *numberOfReturnedProperties = count; | |
497 | ||
498 | return returnValue; | |
499 | } | |
500 | ||
501 | Protocol **protocol_copyProtocolList (Protocol *protocol, unsigned int *numberOfReturnedProtocols) | |
502 | { | |
503 | unsigned int count = 0; | |
504 | Protocol **returnValue = NULL; | |
505 | struct objc_protocol_list* proto_list; | |
506 | ||
507 | /* Check that it is a Protocol object before casting it to (struct | |
508 | objc_protocol *). */ | |
509 | if (protocol == NULL || protocol->class_pointer != objc_lookUpClass ("Protocol")) | |
510 | { | |
511 | if (numberOfReturnedProtocols) | |
512 | *numberOfReturnedProtocols = 0; | |
513 | ||
514 | return NULL; | |
515 | } | |
516 | ||
517 | /* We do not acquire any lock because protocols are currently | |
518 | immutable. We can freely iterate over a protocol structure. */ | |
519 | ||
520 | /* Count how many protocols we have. */ | |
521 | proto_list = ((struct objc_protocol *)protocol)->protocol_list; | |
522 | ||
523 | while (proto_list) | |
524 | { | |
525 | count = count + proto_list->count; | |
526 | proto_list = proto_list->next; | |
527 | } | |
528 | ||
529 | if (count != 0) | |
530 | { | |
531 | unsigned int i = 0; | |
532 | ||
533 | /* Allocate enough memory to hold them. */ | |
534 | returnValue = (Protocol **)(malloc (sizeof (Protocol *) * (count + 1))); | |
535 | ||
536 | /* Copy the protocols. */ | |
537 | proto_list = ((struct objc_protocol *)protocol)->protocol_list; | |
538 | ||
539 | while (proto_list) | |
540 | { | |
541 | size_t j; | |
542 | for (j = 0; j < proto_list->count; j++) | |
543 | { | |
544 | returnValue[i] = (Protocol *)proto_list->list[j]; | |
545 | i++; | |
546 | } | |
547 | proto_list = proto_list->next; | |
548 | } | |
549 | ||
550 | returnValue[i] = NULL; | |
551 | } | |
552 | ||
553 | if (numberOfReturnedProtocols) | |
554 | *numberOfReturnedProtocols = count; | |
555 | ||
556 | return returnValue; | |
557 | } |