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1 | #ifndef BOOST_THREAD_PTHREAD_SHARED_MUTEX_HPP |
2 | #define BOOST_THREAD_PTHREAD_SHARED_MUTEX_HPP | |
3 | ||
4 | // (C) Copyright 2006-8 Anthony Williams | |
5 | // (C) Copyright 2012 Vicente J. Botet Escriba | |
6 | // | |
7 | // Distributed under the Boost Software License, Version 1.0. (See | |
8 | // accompanying file LICENSE_1_0.txt or copy at | |
9 | // http://www.boost.org/LICENSE_1_0.txt) | |
10 | ||
11 | #include <boost/assert.hpp> | |
12 | #include <boost/static_assert.hpp> | |
13 | #include <boost/thread/mutex.hpp> | |
14 | #include <boost/thread/condition_variable.hpp> | |
15 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
16 | #include <boost/thread/detail/thread_interruption.hpp> | |
17 | #endif | |
18 | #ifdef BOOST_THREAD_USES_CHRONO | |
19 | #include <boost/chrono/system_clocks.hpp> | |
20 | #include <boost/chrono/ceil.hpp> | |
21 | #endif | |
22 | #include <boost/thread/detail/delete.hpp> | |
23 | #include <boost/assert.hpp> | |
24 | ||
25 | #include <boost/config/abi_prefix.hpp> | |
26 | ||
27 | namespace boost | |
28 | { | |
29 | class shared_mutex | |
30 | { | |
31 | private: | |
32 | class state_data | |
33 | { | |
34 | public: | |
35 | state_data () : | |
36 | shared_count(0), | |
37 | exclusive(false), | |
38 | upgrade(false), | |
39 | exclusive_waiting_blocked(false) | |
40 | {} | |
41 | ||
42 | void assert_free() const | |
43 | { | |
44 | BOOST_ASSERT( ! exclusive ); | |
45 | BOOST_ASSERT( ! upgrade ); | |
46 | BOOST_ASSERT( shared_count==0 ); | |
47 | } | |
48 | ||
49 | void assert_locked() const | |
50 | { | |
51 | BOOST_ASSERT( exclusive ); | |
52 | BOOST_ASSERT( shared_count==0 ); | |
53 | BOOST_ASSERT( ! upgrade ); | |
54 | } | |
55 | ||
56 | void assert_lock_shared () const | |
57 | { | |
58 | BOOST_ASSERT( ! exclusive ); | |
59 | BOOST_ASSERT( shared_count>0 ); | |
60 | //BOOST_ASSERT( (! upgrade) || (shared_count>1)); | |
61 | // if upgraded there are at least 2 threads sharing the mutex, | |
62 | // except when unlock_upgrade_and_lock has decreased the number of readers but has not taken yet exclusive ownership. | |
63 | } | |
64 | ||
65 | void assert_lock_upgraded () const | |
66 | { | |
67 | BOOST_ASSERT( ! exclusive ); | |
68 | BOOST_ASSERT( upgrade ); | |
69 | BOOST_ASSERT( shared_count>0 ); | |
70 | } | |
71 | ||
72 | void assert_lock_not_upgraded () const | |
73 | { | |
74 | BOOST_ASSERT( ! upgrade ); | |
75 | } | |
76 | ||
77 | bool can_lock () const | |
78 | { | |
79 | return ! (shared_count || exclusive); | |
80 | } | |
81 | ||
82 | void exclusive_blocked (bool blocked) | |
83 | { | |
84 | exclusive_waiting_blocked = blocked; | |
85 | } | |
86 | ||
87 | void lock () | |
88 | { | |
89 | exclusive = true; | |
90 | } | |
91 | ||
92 | void unlock () | |
93 | { | |
94 | exclusive = false; | |
95 | exclusive_waiting_blocked = false; | |
96 | } | |
97 | ||
98 | bool can_lock_shared () const | |
99 | { | |
100 | return ! (exclusive || exclusive_waiting_blocked); | |
101 | } | |
102 | ||
103 | bool is_last_shared () const | |
104 | { | |
105 | return !shared_count ; | |
106 | } | |
107 | unsigned get_shared_count () const | |
108 | { | |
109 | return shared_count ; | |
110 | } | |
111 | unsigned lock_shared () | |
112 | { | |
113 | return ++shared_count; | |
114 | } | |
115 | ||
116 | ||
117 | void unlock_shared () | |
118 | { | |
119 | --shared_count; | |
120 | } | |
121 | ||
122 | bool unlock_shared_downgrades() | |
123 | { | |
124 | if (upgrade) { | |
125 | upgrade=false; | |
126 | exclusive=true; | |
127 | return true; | |
128 | } else { | |
129 | exclusive_waiting_blocked=false; | |
130 | return false; | |
131 | } | |
132 | } | |
133 | ||
134 | void lock_upgrade () | |
135 | { | |
136 | lock_shared (); | |
137 | upgrade=true; | |
138 | } | |
139 | bool can_lock_upgrade () const | |
140 | { | |
141 | return ! (exclusive || exclusive_waiting_blocked || upgrade); | |
142 | } | |
143 | ||
144 | void unlock_upgrade () | |
145 | { | |
146 | upgrade=false; | |
147 | unlock_shared(); | |
148 | } | |
149 | ||
150 | //private: | |
151 | unsigned shared_count; | |
152 | bool exclusive; | |
153 | bool upgrade; | |
154 | bool exclusive_waiting_blocked; | |
155 | }; | |
156 | ||
157 | ||
158 | ||
159 | state_data state; | |
160 | boost::mutex state_change; | |
161 | boost::condition_variable shared_cond; | |
162 | boost::condition_variable exclusive_cond; | |
163 | boost::condition_variable upgrade_cond; | |
164 | ||
165 | void release_waiters() | |
166 | { | |
167 | exclusive_cond.notify_one(); | |
168 | shared_cond.notify_all(); | |
169 | } | |
170 | ||
171 | public: | |
172 | BOOST_THREAD_NO_COPYABLE(shared_mutex) | |
173 | ||
174 | shared_mutex() | |
175 | { | |
176 | } | |
177 | ||
178 | ~shared_mutex() | |
179 | { | |
180 | } | |
181 | ||
182 | void lock_shared() | |
183 | { | |
184 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
185 | boost::this_thread::disable_interruption do_not_disturb; | |
186 | #endif | |
187 | boost::unique_lock<boost::mutex> lk(state_change); | |
188 | ||
189 | while(!state.can_lock_shared()) | |
190 | { | |
191 | shared_cond.wait(lk); | |
192 | } | |
193 | state.lock_shared(); | |
194 | } | |
195 | ||
196 | bool try_lock_shared() | |
197 | { | |
198 | boost::unique_lock<boost::mutex> lk(state_change); | |
199 | if(!state.can_lock_shared()) | |
200 | { | |
201 | return false; | |
202 | } | |
203 | else | |
204 | { | |
205 | state.lock_shared(); | |
206 | return true; | |
207 | } | |
208 | } | |
209 | ||
210 | #if defined BOOST_THREAD_USES_DATETIME | |
211 | bool timed_lock_shared(system_time const& timeout) | |
212 | { | |
213 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
214 | boost::this_thread::disable_interruption do_not_disturb; | |
215 | #endif | |
216 | boost::unique_lock<boost::mutex> lk(state_change); | |
217 | ||
218 | while(!state.can_lock_shared()) | |
219 | { | |
220 | if(!shared_cond.timed_wait(lk,timeout)) | |
221 | { | |
222 | return false; | |
223 | } | |
224 | } | |
225 | state.lock_shared(); | |
226 | return true; | |
227 | } | |
228 | ||
229 | template<typename TimeDuration> | |
230 | bool timed_lock_shared(TimeDuration const & relative_time) | |
231 | { | |
232 | return timed_lock_shared(get_system_time()+relative_time); | |
233 | } | |
234 | #endif | |
235 | #ifdef BOOST_THREAD_USES_CHRONO | |
236 | template <class Rep, class Period> | |
237 | bool try_lock_shared_for(const chrono::duration<Rep, Period>& rel_time) | |
238 | { | |
239 | return try_lock_shared_until(chrono::steady_clock::now() + rel_time); | |
240 | } | |
241 | template <class Clock, class Duration> | |
242 | bool try_lock_shared_until(const chrono::time_point<Clock, Duration>& abs_time) | |
243 | { | |
244 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
245 | boost::this_thread::disable_interruption do_not_disturb; | |
246 | #endif | |
247 | boost::unique_lock<boost::mutex> lk(state_change); | |
248 | ||
249 | while(!state.can_lock_shared()) | |
250 | { | |
251 | if(cv_status::timeout==shared_cond.wait_until(lk,abs_time)) | |
252 | { | |
253 | return false; | |
254 | } | |
255 | } | |
256 | state.lock_shared(); | |
257 | return true; | |
258 | } | |
259 | #endif | |
260 | void unlock_shared() | |
261 | { | |
262 | boost::unique_lock<boost::mutex> lk(state_change); | |
263 | state.assert_lock_shared(); | |
264 | state.unlock_shared(); | |
265 | if (state.get_shared_count () == 0) | |
266 | { | |
267 | if (state.unlock_shared_downgrades()) | |
268 | { | |
269 | lk.unlock(); | |
270 | upgrade_cond.notify_one(); | |
271 | } else { | |
272 | lk.unlock(); | |
273 | } | |
274 | release_waiters(); | |
275 | } | |
276 | } | |
277 | ||
278 | void lock() | |
279 | { | |
280 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
281 | boost::this_thread::disable_interruption do_not_disturb; | |
282 | #endif | |
283 | boost::unique_lock<boost::mutex> lk(state_change); | |
284 | ||
285 | while(!state.can_lock()) | |
286 | { | |
287 | state.exclusive_blocked(true); | |
288 | exclusive_cond.wait(lk); | |
289 | } | |
290 | state.lock(); | |
291 | } | |
292 | ||
293 | #if defined BOOST_THREAD_USES_DATETIME | |
294 | bool timed_lock(system_time const& timeout) | |
295 | { | |
296 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
297 | boost::this_thread::disable_interruption do_not_disturb; | |
298 | #endif | |
299 | boost::unique_lock<boost::mutex> lk(state_change); | |
300 | ||
301 | while(!state.can_lock()) | |
302 | { | |
303 | state.exclusive_blocked(true); | |
304 | if(!exclusive_cond.timed_wait(lk,timeout)) | |
305 | { | |
306 | if(!state.can_lock()) | |
307 | { | |
308 | state.exclusive_blocked(false); | |
309 | release_waiters(); | |
310 | return false; | |
311 | } | |
312 | break; | |
313 | } | |
314 | } | |
315 | state.exclusive=true; | |
316 | //state.lock(); | |
317 | return true; | |
318 | } | |
319 | ||
320 | template<typename TimeDuration> | |
321 | bool timed_lock(TimeDuration const & relative_time) | |
322 | { | |
323 | return timed_lock(get_system_time()+relative_time); | |
324 | } | |
325 | #endif | |
326 | #ifdef BOOST_THREAD_USES_CHRONO | |
327 | template <class Rep, class Period> | |
328 | bool try_lock_for(const chrono::duration<Rep, Period>& rel_time) | |
329 | { | |
330 | return try_lock_until(chrono::steady_clock::now() + rel_time); | |
331 | } | |
332 | template <class Clock, class Duration> | |
333 | bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time) | |
334 | { | |
335 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
336 | boost::this_thread::disable_interruption do_not_disturb; | |
337 | #endif | |
338 | boost::unique_lock<boost::mutex> lk(state_change); | |
339 | ||
340 | while(!state.can_lock()) | |
341 | { | |
342 | state.exclusive_blocked(true); | |
343 | if(cv_status::timeout == exclusive_cond.wait_until(lk,abs_time)) | |
344 | { | |
345 | if(!state.can_lock()) | |
346 | { | |
347 | state.exclusive_blocked(false); | |
348 | release_waiters(); | |
349 | return false; | |
350 | } | |
351 | break; | |
352 | } | |
353 | } | |
354 | state.exclusive=true; | |
355 | //state.lock(); | |
356 | return true; | |
357 | } | |
358 | #endif | |
359 | ||
360 | bool try_lock() | |
361 | { | |
362 | boost::unique_lock<boost::mutex> lk(state_change); | |
363 | ||
364 | if(!state.can_lock()) | |
365 | { | |
366 | return false; | |
367 | } | |
368 | else | |
369 | { | |
370 | state.lock(); | |
371 | return true; | |
372 | } | |
373 | ||
374 | } | |
375 | ||
376 | void unlock() | |
377 | { | |
378 | boost::unique_lock<boost::mutex> lk(state_change); | |
379 | state.assert_locked(); | |
380 | state.unlock(); | |
381 | state.assert_free(); | |
382 | release_waiters(); | |
383 | } | |
384 | ||
385 | void lock_upgrade() | |
386 | { | |
387 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
388 | boost::this_thread::disable_interruption do_not_disturb; | |
389 | #endif | |
390 | boost::unique_lock<boost::mutex> lk(state_change); | |
391 | while(!state.can_lock_upgrade()) | |
392 | { | |
393 | shared_cond.wait(lk); | |
394 | } | |
395 | state.lock_upgrade(); | |
396 | } | |
397 | ||
398 | #if defined BOOST_THREAD_USES_DATETIME | |
399 | bool timed_lock_upgrade(system_time const& timeout) | |
400 | { | |
401 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
402 | boost::this_thread::disable_interruption do_not_disturb; | |
403 | #endif | |
404 | boost::unique_lock<boost::mutex> lk(state_change); | |
405 | while(!state.can_lock_upgrade()) | |
406 | { | |
407 | if(!shared_cond.timed_wait(lk,timeout)) | |
408 | { | |
409 | if(!state.can_lock_upgrade()) | |
410 | { | |
411 | return false; | |
412 | } | |
413 | break; | |
414 | } | |
415 | } | |
416 | state.lock_upgrade(); | |
417 | return true; | |
418 | } | |
419 | ||
420 | template<typename TimeDuration> | |
421 | bool timed_lock_upgrade(TimeDuration const & relative_time) | |
422 | { | |
423 | return timed_lock_upgrade(get_system_time()+relative_time); | |
424 | } | |
425 | #endif | |
426 | #ifdef BOOST_THREAD_USES_CHRONO | |
427 | template <class Rep, class Period> | |
428 | bool try_lock_upgrade_for(const chrono::duration<Rep, Period>& rel_time) | |
429 | { | |
430 | return try_lock_upgrade_until(chrono::steady_clock::now() + rel_time); | |
431 | } | |
432 | template <class Clock, class Duration> | |
433 | bool try_lock_upgrade_until(const chrono::time_point<Clock, Duration>& abs_time) | |
434 | { | |
435 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
436 | boost::this_thread::disable_interruption do_not_disturb; | |
437 | #endif | |
438 | boost::unique_lock<boost::mutex> lk(state_change); | |
439 | while(!state.can_lock_upgrade()) | |
440 | { | |
441 | if(cv_status::timeout == shared_cond.wait_until(lk,abs_time)) | |
442 | { | |
443 | if(!state.can_lock_upgrade()) | |
444 | { | |
445 | return false; | |
446 | } | |
447 | break; | |
448 | } | |
449 | } | |
450 | state.lock_upgrade(); | |
451 | return true; | |
452 | } | |
453 | #endif | |
454 | bool try_lock_upgrade() | |
455 | { | |
456 | boost::unique_lock<boost::mutex> lk(state_change); | |
457 | if(!state.can_lock_upgrade()) | |
458 | { | |
459 | return false; | |
460 | } | |
461 | else | |
462 | { | |
463 | state.lock_upgrade(); | |
464 | state.assert_lock_upgraded(); | |
465 | return true; | |
466 | } | |
467 | } | |
468 | ||
469 | void unlock_upgrade() | |
470 | { | |
471 | boost::unique_lock<boost::mutex> lk(state_change); | |
472 | state.assert_lock_upgraded(); | |
473 | state.unlock_upgrade(); | |
474 | state.assert_lock_not_upgraded (); | |
475 | if(state.get_shared_count () == 0) | |
476 | { | |
477 | state.exclusive_blocked(false); | |
478 | lk.unlock(); | |
479 | release_waiters(); | |
480 | } else { | |
481 | lk.unlock(); | |
482 | shared_cond.notify_all(); | |
483 | } | |
484 | } | |
485 | ||
486 | // Upgrade <-> Exclusive | |
487 | void unlock_upgrade_and_lock() | |
488 | { | |
489 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
490 | boost::this_thread::disable_interruption do_not_disturb; | |
491 | #endif | |
492 | boost::unique_lock<boost::mutex> lk(state_change); | |
493 | state.assert_lock_upgraded(); | |
494 | // assert state.get_shared_count() >=1 | |
495 | while( | |
496 | //! state.exclusive_waiting_blocked // Fixme: is this needed? | |
497 | //&& | |
498 | state.get_shared_count()!=1) | |
499 | { | |
500 | upgrade_cond.wait(lk); | |
501 | } | |
502 | state.unlock_upgrade(); | |
503 | state.lock(); | |
504 | state.assert_locked(); | |
505 | } | |
506 | ||
507 | void unlock_and_lock_upgrade() | |
508 | { | |
509 | boost::unique_lock<boost::mutex> lk(state_change); | |
510 | state.assert_locked(); | |
511 | state.unlock(); | |
512 | state.lock_upgrade(); | |
513 | state.assert_lock_upgraded(); | |
514 | release_waiters(); | |
515 | } | |
516 | ||
517 | bool try_unlock_upgrade_and_lock() | |
518 | { | |
519 | boost::unique_lock<boost::mutex> lk(state_change); | |
520 | state.assert_lock_upgraded(); | |
521 | if( //!state.exclusive // this should be removed once the assertion work | |
522 | ! state.exclusive_waiting_blocked // Fixme: why this is needed? | |
523 | //&& state.upgrade // this should be removed once the assertion work | |
524 | && state.get_shared_count()==1) | |
525 | { | |
526 | state.unlock_upgrade(); | |
527 | state.lock(); | |
528 | state.assert_locked(); | |
529 | return true; | |
530 | } | |
531 | return false; | |
532 | } | |
533 | #ifdef BOOST_THREAD_USES_CHRONO | |
534 | template <class Rep, class Period> | |
535 | bool | |
536 | try_unlock_upgrade_and_lock_for( | |
537 | const chrono::duration<Rep, Period>& rel_time) | |
538 | { | |
539 | return try_unlock_upgrade_and_lock_until( | |
540 | chrono::steady_clock::now() + rel_time); | |
541 | } | |
542 | template <class Clock, class Duration> | |
543 | bool | |
544 | try_unlock_upgrade_and_lock_until( | |
545 | const chrono::time_point<Clock, Duration>& abs_time) | |
546 | { | |
547 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
548 | boost::this_thread::disable_interruption do_not_disturb; | |
549 | #endif | |
550 | boost::unique_lock<boost::mutex> lk(state_change); | |
551 | state.assert_lock_upgraded(); | |
552 | if (//state.exclusive // this should be removed once the assertion work | |
553 | state.exclusive_waiting_blocked // Fixme: is this needed? | |
554 | //|| ! state.upgrade // this should be removed once the assertion work | |
555 | || state.get_shared_count() != 1) | |
556 | { | |
557 | for (;;) | |
558 | { | |
559 | //cv_status status = shared_cond.wait_until(lk,abs_time); | |
560 | cv_status status = upgrade_cond.wait_until(lk,abs_time); | |
561 | if (//!state.exclusive // this should be removed once the assertion work | |
562 | ! state.exclusive_waiting_blocked // Fixme: is this needed? | |
563 | //&& ! state.upgrade // this should be removed once the assertion work | |
564 | && state.get_shared_count() == 1) | |
565 | break; | |
566 | if(status == cv_status::timeout) | |
567 | return false; | |
568 | } | |
569 | } | |
570 | state.unlock_upgrade(); | |
571 | state.lock(); | |
572 | return true; | |
573 | } | |
574 | #endif | |
575 | ||
576 | // Shared <-> Exclusive | |
577 | void unlock_and_lock_shared() | |
578 | { | |
579 | boost::unique_lock<boost::mutex> lk(state_change); | |
580 | state.assert_locked(); | |
581 | state.unlock(); | |
582 | state.lock_shared(); | |
583 | release_waiters(); | |
584 | } | |
585 | ||
586 | #ifdef BOOST_THREAD_PROVIDES_SHARED_MUTEX_UPWARDS_CONVERSIONS | |
587 | bool try_unlock_shared_and_lock() | |
588 | { | |
589 | boost::unique_lock<boost::mutex> lk(state_change); | |
590 | state.assert_lock_shared(); | |
591 | if( //!state.exclusive // this should be removed once the assertion work | |
592 | ! state.exclusive_waiting_blocked // Fixme: why this is needed? | |
593 | //&& ! state.upgrade // Fixme: why this is needed if state.get_shared_count()==1? | |
594 | && state.get_shared_count()==1) | |
595 | { | |
596 | state.unlock_shared(); | |
597 | state.lock(); | |
598 | return true; | |
599 | } | |
600 | return false; | |
601 | } | |
602 | #ifdef BOOST_THREAD_USES_CHRONO | |
603 | template <class Rep, class Period> | |
604 | bool | |
605 | try_unlock_shared_and_lock_for( | |
606 | const chrono::duration<Rep, Period>& rel_time) | |
607 | { | |
608 | return try_unlock_shared_and_lock_until( | |
609 | chrono::steady_clock::now() + rel_time); | |
610 | } | |
611 | template <class Clock, class Duration> | |
612 | bool | |
613 | try_unlock_shared_and_lock_until( | |
614 | const chrono::time_point<Clock, Duration>& abs_time) | |
615 | { | |
616 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
617 | boost::this_thread::disable_interruption do_not_disturb; | |
618 | #endif | |
619 | boost::unique_lock<boost::mutex> lk(state_change); | |
620 | state.assert_lock_shared(); | |
621 | if ( // !state.exclusive // this should be removed once the assertion work | |
622 | state.exclusive_waiting_blocked // Fixme: is this needed? | |
623 | //|| state.upgrade // Fixme: why this is needed if state.get_shared_count()==1? | |
624 | || state.get_shared_count() != 1) | |
625 | { | |
626 | for (;;) | |
627 | { | |
628 | cv_status status = shared_cond.wait_until(lk,abs_time); | |
629 | if ( //! state.exclusive // this should be removed once the assertion work | |
630 | ! state.exclusive_waiting_blocked // Fixme: is this needed? | |
631 | //&& ! state.upgrade | |
632 | && state.get_shared_count() == 1) | |
633 | break; | |
634 | if(status == cv_status::timeout) | |
635 | return false; | |
636 | } | |
637 | } | |
638 | state.unlock_shared(); | |
639 | state.lock(); | |
640 | state.upgrade=false; // Is this absolutely needed? | |
641 | state.exclusive_waiting_blocked=false; // Is this absolutely needed? | |
642 | return true; | |
643 | } | |
644 | #endif | |
645 | #endif | |
646 | ||
647 | // Shared <-> Upgrade | |
648 | void unlock_upgrade_and_lock_shared() | |
649 | { | |
650 | boost::unique_lock<boost::mutex> lk(state_change); | |
651 | state.assert_lock_upgraded(); | |
652 | //state.unlock_upgrade(); | |
653 | //state.lock_shared(); // less efficient | |
654 | state.upgrade=false; | |
655 | state.exclusive_waiting_blocked=false; // Is this absolutely needed? | |
656 | release_waiters(); | |
657 | } | |
658 | ||
659 | #ifdef BOOST_THREAD_PROVIDES_SHARED_MUTEX_UPWARDS_CONVERSIONS | |
660 | bool try_unlock_shared_and_lock_upgrade() | |
661 | { | |
662 | boost::unique_lock<boost::mutex> lk(state_change); | |
663 | state.assert_lock_shared(); | |
664 | if( //! state.exclusive // this should be removed once the assertion work | |
665 | ! state.exclusive_waiting_blocked // Fixme: is this needed? | |
666 | && ! state.upgrade | |
667 | ) | |
668 | { | |
669 | state.upgrade=true; | |
670 | return true; | |
671 | } | |
672 | return false; | |
673 | } | |
674 | #ifdef BOOST_THREAD_USES_CHRONO | |
675 | template <class Rep, class Period> | |
676 | bool | |
677 | try_unlock_shared_and_lock_upgrade_for( | |
678 | const chrono::duration<Rep, Period>& rel_time) | |
679 | { | |
680 | return try_unlock_shared_and_lock_upgrade_until( | |
681 | chrono::steady_clock::now() + rel_time); | |
682 | } | |
683 | template <class Clock, class Duration> | |
684 | bool | |
685 | try_unlock_shared_and_lock_upgrade_until( | |
686 | const chrono::time_point<Clock, Duration>& abs_time) | |
687 | { | |
688 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
689 | boost::this_thread::disable_interruption do_not_disturb; | |
690 | #endif | |
691 | boost::unique_lock<boost::mutex> lk(state_change); | |
692 | state.assert_lock_shared(); | |
693 | if( //state.exclusive // this should be removed once the assertion work | |
694 | state.exclusive_waiting_blocked // Fixme: is this needed? | |
695 | || state.upgrade | |
696 | ) | |
697 | { | |
698 | for (;;) | |
699 | { | |
700 | cv_status status = exclusive_cond.wait_until(lk,abs_time); | |
701 | if( //! state.exclusive // this should be removed once the assertion work | |
702 | ! state.exclusive_waiting_blocked // Fixme: is this needed? | |
703 | && ! state.upgrade | |
704 | ) | |
705 | break; | |
706 | if(status == cv_status::timeout) | |
707 | return false; | |
708 | } | |
709 | } | |
710 | //state.unlock_shared(); | |
711 | //state.lock_upgrade(); // less efficient | |
712 | state.upgrade=true; | |
713 | return true; | |
714 | } | |
715 | #endif | |
716 | #endif | |
717 | }; | |
718 | ||
719 | typedef shared_mutex upgrade_mutex; | |
720 | } | |
721 | ||
722 | #include <boost/config/abi_suffix.hpp> | |
723 | ||
724 | #endif |