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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 more_shared () const | |
104 | { | |
105 | return shared_count > 0 ; | |
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 | ++shared_count; | |
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 | --shared_count; | |
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 | ||
173 | BOOST_THREAD_NO_COPYABLE(shared_mutex) | |
174 | ||
175 | shared_mutex() | |
176 | { | |
177 | } | |
178 | ||
179 | ~shared_mutex() | |
180 | { | |
181 | } | |
182 | ||
183 | void lock_shared() | |
184 | { | |
185 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
186 | boost::this_thread::disable_interruption do_not_disturb; | |
187 | #endif | |
188 | boost::unique_lock<boost::mutex> lk(state_change); | |
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 | ||
200 | if(!state.can_lock_shared()) | |
201 | { | |
202 | return false; | |
203 | } | |
204 | state.lock_shared(); | |
205 | return true; | |
206 | } | |
207 | ||
208 | #if defined BOOST_THREAD_USES_DATETIME | |
209 | bool timed_lock_shared(system_time const& timeout) | |
210 | { | |
211 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
212 | boost::this_thread::disable_interruption do_not_disturb; | |
213 | #endif | |
214 | boost::unique_lock<boost::mutex> lk(state_change); | |
215 | ||
216 | while(!state.can_lock_shared()) | |
217 | { | |
218 | if(!shared_cond.timed_wait(lk,timeout)) | |
219 | { | |
220 | return false; | |
221 | } | |
222 | } | |
223 | state.lock_shared(); | |
224 | return true; | |
225 | } | |
226 | ||
227 | template<typename TimeDuration> | |
228 | bool timed_lock_shared(TimeDuration const & relative_time) | |
229 | { | |
230 | return timed_lock_shared(get_system_time()+relative_time); | |
231 | } | |
232 | #endif | |
233 | #ifdef BOOST_THREAD_USES_CHRONO | |
234 | template <class Rep, class Period> | |
235 | bool try_lock_shared_for(const chrono::duration<Rep, Period>& rel_time) | |
236 | { | |
237 | return try_lock_shared_until(chrono::steady_clock::now() + rel_time); | |
238 | } | |
239 | template <class Clock, class Duration> | |
240 | bool try_lock_shared_until(const chrono::time_point<Clock, Duration>& abs_time) | |
241 | { | |
242 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
243 | boost::this_thread::disable_interruption do_not_disturb; | |
244 | #endif | |
245 | boost::unique_lock<boost::mutex> lk(state_change); | |
246 | ||
247 | while(!state.can_lock_shared()) | |
248 | //while(state.exclusive || state.exclusive_waiting_blocked) | |
249 | { | |
250 | if(cv_status::timeout==shared_cond.wait_until(lk,abs_time)) | |
251 | { | |
252 | return false; | |
253 | } | |
254 | } | |
255 | state.lock_shared(); | |
256 | return true; | |
257 | } | |
258 | #endif | |
259 | void unlock_shared() | |
260 | { | |
261 | boost::unique_lock<boost::mutex> lk(state_change); | |
262 | state.assert_lock_shared(); | |
263 | state.unlock_shared(); | |
264 | if (! state.more_shared()) | |
265 | { | |
266 | if (state.upgrade) | |
267 | { | |
268 | // As there is a thread doing a unlock_upgrade_and_lock that is waiting for ! state.more_shared() | |
269 | // avoid other threads to lock, lock_upgrade or lock_shared, so only this thread is notified. | |
270 | state.upgrade=false; | |
271 | state.exclusive=true; | |
272 | //lk.unlock(); | |
273 | upgrade_cond.notify_one(); | |
274 | } | |
275 | else | |
276 | { | |
277 | state.exclusive_waiting_blocked=false; | |
278 | //lk.unlock(); | |
279 | } | |
280 | release_waiters(); | |
281 | } | |
282 | } | |
283 | ||
284 | void lock() | |
285 | { | |
286 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
287 | boost::this_thread::disable_interruption do_not_disturb; | |
288 | #endif | |
289 | boost::unique_lock<boost::mutex> lk(state_change); | |
290 | ||
291 | while (state.shared_count || state.exclusive) | |
292 | { | |
293 | state.exclusive_waiting_blocked=true; | |
294 | exclusive_cond.wait(lk); | |
295 | } | |
296 | state.exclusive=true; | |
297 | } | |
298 | ||
299 | #if defined BOOST_THREAD_USES_DATETIME | |
300 | bool timed_lock(system_time const& timeout) | |
301 | { | |
302 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
303 | boost::this_thread::disable_interruption do_not_disturb; | |
304 | #endif | |
305 | boost::unique_lock<boost::mutex> lk(state_change); | |
306 | ||
307 | while(state.shared_count || state.exclusive) | |
308 | { | |
309 | state.exclusive_waiting_blocked=true; | |
310 | if(!exclusive_cond.timed_wait(lk,timeout)) | |
311 | { | |
312 | if(state.shared_count || state.exclusive) | |
313 | { | |
314 | state.exclusive_waiting_blocked=false; | |
315 | release_waiters(); | |
316 | return false; | |
317 | } | |
318 | break; | |
319 | } | |
320 | } | |
321 | state.exclusive=true; | |
322 | return true; | |
323 | } | |
324 | ||
325 | template<typename TimeDuration> | |
326 | bool timed_lock(TimeDuration const & relative_time) | |
327 | { | |
328 | return timed_lock(get_system_time()+relative_time); | |
329 | } | |
330 | #endif | |
331 | #ifdef BOOST_THREAD_USES_CHRONO | |
332 | template <class Rep, class Period> | |
333 | bool try_lock_for(const chrono::duration<Rep, Period>& rel_time) | |
334 | { | |
335 | return try_lock_until(chrono::steady_clock::now() + rel_time); | |
336 | } | |
337 | template <class Clock, class Duration> | |
338 | bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time) | |
339 | { | |
340 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
341 | boost::this_thread::disable_interruption do_not_disturb; | |
342 | #endif | |
343 | boost::unique_lock<boost::mutex> lk(state_change); | |
344 | ||
345 | while(state.shared_count || state.exclusive) | |
346 | { | |
347 | state.exclusive_waiting_blocked=true; | |
348 | if(cv_status::timeout == exclusive_cond.wait_until(lk,abs_time)) | |
349 | { | |
350 | if(state.shared_count || state.exclusive) | |
351 | { | |
352 | state.exclusive_waiting_blocked=false; | |
353 | release_waiters(); | |
354 | return false; | |
355 | } | |
356 | break; | |
357 | } | |
358 | } | |
359 | state.exclusive=true; | |
360 | return true; | |
361 | } | |
362 | #endif | |
363 | ||
364 | bool try_lock() | |
365 | { | |
366 | boost::unique_lock<boost::mutex> lk(state_change); | |
367 | ||
368 | if(state.shared_count || state.exclusive) | |
369 | { | |
370 | return false; | |
371 | } | |
372 | else | |
373 | { | |
374 | state.exclusive=true; | |
375 | return true; | |
376 | } | |
377 | ||
378 | } | |
379 | ||
380 | void unlock() | |
381 | { | |
382 | boost::unique_lock<boost::mutex> lk(state_change); | |
383 | state.assert_locked(); | |
384 | state.exclusive=false; | |
385 | state.exclusive_waiting_blocked=false; | |
386 | state.assert_free(); | |
387 | release_waiters(); | |
388 | } | |
389 | ||
390 | void lock_upgrade() | |
391 | { | |
392 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
393 | boost::this_thread::disable_interruption do_not_disturb; | |
394 | #endif | |
395 | boost::unique_lock<boost::mutex> lk(state_change); | |
396 | while(state.exclusive || state.exclusive_waiting_blocked || state.upgrade) | |
397 | { | |
398 | shared_cond.wait(lk); | |
399 | } | |
400 | state.lock_shared(); | |
401 | state.upgrade=true; | |
402 | } | |
403 | ||
404 | #if defined BOOST_THREAD_USES_DATETIME | |
405 | bool timed_lock_upgrade(system_time const& timeout) | |
406 | { | |
407 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
408 | boost::this_thread::disable_interruption do_not_disturb; | |
409 | #endif | |
410 | boost::unique_lock<boost::mutex> lk(state_change); | |
411 | while(state.exclusive || state.exclusive_waiting_blocked || state.upgrade) | |
412 | { | |
413 | if(!shared_cond.timed_wait(lk,timeout)) | |
414 | { | |
415 | if(state.exclusive || state.exclusive_waiting_blocked || state.upgrade) | |
416 | { | |
417 | return false; | |
418 | } | |
419 | break; | |
420 | } | |
421 | } | |
422 | state.lock_shared(); | |
423 | state.upgrade=true; | |
424 | return true; | |
425 | } | |
426 | ||
427 | template<typename TimeDuration> | |
428 | bool timed_lock_upgrade(TimeDuration const & relative_time) | |
429 | { | |
430 | return timed_lock_upgrade(get_system_time()+relative_time); | |
431 | } | |
432 | #endif | |
433 | #ifdef BOOST_THREAD_USES_CHRONO | |
434 | template <class Rep, class Period> | |
435 | bool try_lock_upgrade_for(const chrono::duration<Rep, Period>& rel_time) | |
436 | { | |
437 | return try_lock_upgrade_until(chrono::steady_clock::now() + rel_time); | |
438 | } | |
439 | template <class Clock, class Duration> | |
440 | bool try_lock_upgrade_until(const chrono::time_point<Clock, Duration>& abs_time) | |
441 | { | |
442 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
443 | boost::this_thread::disable_interruption do_not_disturb; | |
444 | #endif | |
445 | boost::unique_lock<boost::mutex> lk(state_change); | |
446 | while(state.exclusive || state.exclusive_waiting_blocked || state.upgrade) | |
447 | { | |
448 | if(cv_status::timeout == shared_cond.wait_until(lk,abs_time)) | |
449 | { | |
450 | if(state.exclusive || state.exclusive_waiting_blocked || state.upgrade) | |
451 | { | |
452 | return false; | |
453 | } | |
454 | break; | |
455 | } | |
456 | } | |
457 | state.lock_shared(); | |
458 | state.upgrade=true; | |
459 | return true; | |
460 | } | |
461 | #endif | |
462 | bool try_lock_upgrade() | |
463 | { | |
464 | boost::unique_lock<boost::mutex> lk(state_change); | |
465 | if(state.exclusive || state.exclusive_waiting_blocked || state.upgrade) | |
466 | { | |
467 | return false; | |
468 | } | |
469 | else | |
470 | { | |
471 | state.lock_shared(); | |
472 | state.upgrade=true; | |
473 | state.assert_lock_upgraded(); | |
474 | return true; | |
475 | } | |
476 | } | |
477 | ||
478 | void unlock_upgrade() | |
479 | { | |
480 | boost::unique_lock<boost::mutex> lk(state_change); | |
481 | //state.upgrade=false; | |
482 | state.unlock_upgrade(); | |
483 | if(! state.more_shared() ) | |
484 | { | |
485 | state.exclusive_waiting_blocked=false; | |
486 | release_waiters(); | |
487 | } else { | |
488 | shared_cond.notify_all(); | |
489 | } | |
490 | } | |
491 | ||
492 | // Upgrade <-> Exclusive | |
493 | void unlock_upgrade_and_lock() | |
494 | { | |
495 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
496 | boost::this_thread::disable_interruption do_not_disturb; | |
497 | #endif | |
498 | boost::unique_lock<boost::mutex> lk(state_change); | |
499 | state.assert_lock_upgraded(); | |
500 | state.unlock_shared(); | |
501 | while (state.more_shared()) | |
502 | { | |
503 | upgrade_cond.wait(lk); | |
504 | } | |
505 | state.upgrade=false; | |
506 | state.exclusive=true; | |
507 | state.assert_locked(); | |
508 | } | |
509 | ||
510 | void unlock_and_lock_upgrade() | |
511 | { | |
512 | boost::unique_lock<boost::mutex> lk(state_change); | |
513 | state.assert_locked(); | |
514 | state.exclusive=false; | |
515 | state.upgrade=true; | |
516 | state.lock_shared(); | |
517 | state.exclusive_waiting_blocked=false; | |
518 | state.assert_lock_upgraded(); | |
519 | release_waiters(); | |
520 | } | |
521 | ||
522 | bool try_unlock_upgrade_and_lock() | |
523 | { | |
524 | boost::unique_lock<boost::mutex> lk(state_change); | |
525 | state.assert_lock_upgraded(); | |
526 | if( !state.exclusive | |
527 | && !state.exclusive_waiting_blocked | |
528 | && state.upgrade | |
529 | && state.shared_count==1) | |
530 | { | |
531 | state.shared_count=0; | |
532 | state.exclusive=true; | |
533 | state.upgrade=false; | |
534 | state.assert_locked(); | |
535 | return true; | |
536 | } | |
537 | return false; | |
538 | } | |
539 | #ifdef BOOST_THREAD_USES_CHRONO | |
540 | template <class Rep, class Period> | |
541 | bool | |
542 | try_unlock_upgrade_and_lock_for( | |
543 | const chrono::duration<Rep, Period>& rel_time) | |
544 | { | |
545 | return try_unlock_upgrade_and_lock_until( | |
546 | chrono::steady_clock::now() + rel_time); | |
547 | } | |
548 | template <class Clock, class Duration> | |
549 | bool | |
550 | try_unlock_upgrade_and_lock_until( | |
551 | const chrono::time_point<Clock, Duration>& abs_time) | |
552 | { | |
553 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
554 | boost::this_thread::disable_interruption do_not_disturb; | |
555 | #endif | |
556 | boost::unique_lock<boost::mutex> lk(state_change); | |
557 | state.assert_lock_upgraded(); | |
558 | if (state.shared_count != 1) | |
559 | { | |
560 | for (;;) | |
561 | { | |
562 | cv_status status = shared_cond.wait_until(lk,abs_time); | |
563 | if (state.shared_count == 1) | |
564 | break; | |
565 | if(status == cv_status::timeout) | |
566 | return false; | |
567 | } | |
568 | } | |
569 | state.upgrade=false; | |
570 | state.exclusive=true; | |
571 | state.exclusive_waiting_blocked=false; | |
572 | state.shared_count=0; | |
573 | return true; | |
574 | } | |
575 | #endif | |
576 | ||
577 | // Shared <-> Exclusive | |
578 | void unlock_and_lock_shared() | |
579 | { | |
580 | boost::unique_lock<boost::mutex> lk(state_change); | |
581 | state.assert_locked(); | |
582 | state.exclusive=false; | |
583 | state.lock_shared(); | |
584 | state.exclusive_waiting_blocked=false; | |
585 | release_waiters(); | |
586 | } | |
587 | ||
588 | #ifdef BOOST_THREAD_PROVIDES_SHARED_MUTEX_UPWARDS_CONVERSIONS | |
589 | bool try_unlock_shared_and_lock() | |
590 | { | |
591 | boost::unique_lock<boost::mutex> lk(state_change); | |
592 | state.assert_lock_shared(); | |
593 | if( !state.exclusive | |
594 | && !state.exclusive_waiting_blocked | |
595 | && !state.upgrade | |
596 | && state.shared_count==1) | |
597 | { | |
598 | state.shared_count=0; | |
599 | state.exclusive=true; | |
600 | return true; | |
601 | } | |
602 | return false; | |
603 | } | |
604 | #ifdef BOOST_THREAD_USES_CHRONO | |
605 | template <class Rep, class Period> | |
606 | bool | |
607 | try_unlock_shared_and_lock_for( | |
608 | const chrono::duration<Rep, Period>& rel_time) | |
609 | { | |
610 | return try_unlock_shared_and_lock_until( | |
611 | chrono::steady_clock::now() + rel_time); | |
612 | } | |
613 | template <class Clock, class Duration> | |
614 | bool | |
615 | try_unlock_shared_and_lock_until( | |
616 | const chrono::time_point<Clock, Duration>& abs_time) | |
617 | { | |
618 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
619 | boost::this_thread::disable_interruption do_not_disturb; | |
620 | #endif | |
621 | boost::unique_lock<boost::mutex> lk(state_change); | |
622 | state.assert_lock_shared(); | |
623 | if (state.shared_count != 1) | |
624 | { | |
625 | for (;;) | |
626 | { | |
627 | cv_status status = shared_cond.wait_until(lk,abs_time); | |
628 | if (state.shared_count == 1) | |
629 | break; | |
630 | if(status == cv_status::timeout) | |
631 | return false; | |
632 | } | |
633 | } | |
634 | state.upgrade=false; | |
635 | state.exclusive=true; | |
636 | state.exclusive_waiting_blocked=false; | |
637 | state.shared_count=0; | |
638 | return true; | |
639 | } | |
640 | #endif | |
641 | #endif | |
642 | ||
643 | // Shared <-> Upgrade | |
644 | void unlock_upgrade_and_lock_shared() | |
645 | { | |
646 | boost::unique_lock<boost::mutex> lk(state_change); | |
647 | state.assert_lock_upgraded(); | |
648 | state.upgrade=false; | |
649 | state.exclusive_waiting_blocked=false; | |
650 | release_waiters(); | |
651 | } | |
652 | ||
653 | #ifdef BOOST_THREAD_PROVIDES_SHARED_MUTEX_UPWARDS_CONVERSIONS | |
654 | bool try_unlock_shared_and_lock_upgrade() | |
655 | { | |
656 | boost::unique_lock<boost::mutex> lk(state_change); | |
657 | state.assert_lock_shared(); | |
658 | if( !state.exclusive | |
659 | && !state.exclusive_waiting_blocked | |
660 | && !state.upgrade | |
661 | ) | |
662 | { | |
663 | state.upgrade=true; | |
664 | return true; | |
665 | } | |
666 | return false; | |
667 | } | |
668 | #ifdef BOOST_THREAD_USES_CHRONO | |
669 | template <class Rep, class Period> | |
670 | bool | |
671 | try_unlock_shared_and_lock_upgrade_for( | |
672 | const chrono::duration<Rep, Period>& rel_time) | |
673 | { | |
674 | return try_unlock_shared_and_lock_upgrade_until( | |
675 | chrono::steady_clock::now() + rel_time); | |
676 | } | |
677 | template <class Clock, class Duration> | |
678 | bool | |
679 | try_unlock_shared_and_lock_upgrade_until( | |
680 | const chrono::time_point<Clock, Duration>& abs_time) | |
681 | { | |
682 | #if defined BOOST_THREAD_PROVIDES_INTERRUPTIONS | |
683 | boost::this_thread::disable_interruption do_not_disturb; | |
684 | #endif | |
685 | boost::unique_lock<boost::mutex> lk(state_change); | |
686 | state.assert_lock_shared(); | |
687 | if( state.exclusive | |
688 | || state.exclusive_waiting_blocked | |
689 | || state.upgrade | |
690 | ) | |
691 | { | |
692 | for (;;) | |
693 | { | |
694 | cv_status status = exclusive_cond.wait_until(lk,abs_time); | |
695 | if( ! state.exclusive | |
696 | && ! state.exclusive_waiting_blocked | |
697 | && ! state.upgrade | |
698 | ) | |
699 | break; | |
700 | if(status == cv_status::timeout) | |
701 | return false; | |
702 | } | |
703 | } | |
704 | state.upgrade=true; | |
705 | return true; | |
706 | } | |
707 | #endif | |
708 | #endif | |
709 | }; | |
710 | ||
711 | typedef shared_mutex upgrade_mutex; | |
712 | } | |
713 | ||
714 | #include <boost/config/abi_suffix.hpp> | |
715 | ||
716 | #endif |