aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/libs/cxxsupp/libcxx/include/shared_mutex
blob: 350c841e11a0a7c7a7fa7d7757e7a50352216317 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP_SHARED_MUTEX
#define _LIBCPP_SHARED_MUTEX

/*
    shared_mutex synopsis

// C++1y

namespace std
{

class shared_mutex      // C++17
{
public:
    shared_mutex();
    ~shared_mutex();

    shared_mutex(const shared_mutex&) = delete;
    shared_mutex& operator=(const shared_mutex&) = delete;

    // Exclusive ownership
    void lock(); // blocking
    bool try_lock();
    void unlock();

    // Shared ownership
    void lock_shared(); // blocking
    bool try_lock_shared();
    void unlock_shared();

    typedef implementation-defined native_handle_type; // See 30.2.3
    native_handle_type native_handle(); // See 30.2.3
};

class shared_timed_mutex
{
public:
    shared_timed_mutex();
    ~shared_timed_mutex();

    shared_timed_mutex(const shared_timed_mutex&) = delete;
    shared_timed_mutex& operator=(const shared_timed_mutex&) = delete;

    // Exclusive ownership
    void lock(); // blocking
    bool try_lock();
    template <class Rep, class Period>
        bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
    template <class Clock, class Duration>
        bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
    void unlock();

    // Shared ownership
    void lock_shared(); // blocking
    bool try_lock_shared();
    template <class Rep, class Period>
        bool
        try_lock_shared_for(const chrono::duration<Rep, Period>& rel_time);
    template <class Clock, class Duration>
        bool
        try_lock_shared_until(const chrono::time_point<Clock, Duration>& abs_time);
    void unlock_shared();
};

template <class Mutex>
class shared_lock
{
public:
    typedef Mutex mutex_type;

    // Shared locking
    shared_lock() noexcept;
    explicit shared_lock(mutex_type& m); // blocking
    shared_lock(mutex_type& m, defer_lock_t) noexcept;
    shared_lock(mutex_type& m, try_to_lock_t);
    shared_lock(mutex_type& m, adopt_lock_t);
    template <class Clock, class Duration>
        shared_lock(mutex_type& m,
                    const chrono::time_point<Clock, Duration>& abs_time);
    template <class Rep, class Period>
        shared_lock(mutex_type& m,
                    const chrono::duration<Rep, Period>& rel_time);
    ~shared_lock();

    shared_lock(shared_lock const&) = delete;
    shared_lock& operator=(shared_lock const&) = delete;

    shared_lock(shared_lock&& u) noexcept;
    shared_lock& operator=(shared_lock&& u) noexcept;

    void lock(); // blocking
    bool try_lock();
    template <class Rep, class Period>
        bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
    template <class Clock, class Duration>
        bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
    void unlock();

    // Setters
    void swap(shared_lock& u) noexcept;
    mutex_type* release() noexcept;

    // Getters
    bool owns_lock() const noexcept;
    explicit operator bool () const noexcept;
    mutex_type* mutex() const noexcept;
};

template <class Mutex>
    void swap(shared_lock<Mutex>& x, shared_lock<Mutex>& y) noexcept;

}  // std

*/

#include <__assert> // all public C++ headers provide the assertion handler
#include <__availability>
#include <__chrono/duration.h>
#include <__chrono/steady_clock.h>
#include <__chrono/time_point.h>
#include <__condition_variable/condition_variable.h>
#include <__config>
#include <__memory/addressof.h>
#include <__mutex/mutex.h>
#include <__mutex/tag_types.h>
#include <__mutex/unique_lock.h>
#include <__system_error/system_error.h>
#include <__utility/swap.h>
#include <cerrno>
#include <version>

_LIBCPP_PUSH_MACROS
#include <__undef_macros>

#if _LIBCPP_STD_VER >= 14

#  if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#    pragma GCC system_header
#  endif

#  ifdef _LIBCPP_HAS_NO_THREADS
#    error "<shared_mutex> is not supported since libc++ has been configured without support for threads."
#  endif

_LIBCPP_BEGIN_NAMESPACE_STD

struct _LIBCPP_EXPORTED_FROM_ABI _LIBCPP_AVAILABILITY_SHARED_MUTEX __shared_mutex_base {
  mutex __mut_;
  condition_variable __gate1_;
  condition_variable __gate2_;
  unsigned __state_;

  static const unsigned __write_entered_ = 1U << (sizeof(unsigned) * __CHAR_BIT__ - 1);
  static const unsigned __n_readers_     = ~__write_entered_;

  __shared_mutex_base();
  _LIBCPP_HIDE_FROM_ABI ~__shared_mutex_base() = default;

  __shared_mutex_base(const __shared_mutex_base&)            = delete;
  __shared_mutex_base& operator=(const __shared_mutex_base&) = delete;

  // Exclusive ownership
  void lock(); // blocking
  bool try_lock();
  void unlock();

  // Shared ownership
  void lock_shared(); // blocking
  bool try_lock_shared();
  void unlock_shared();

  //     typedef implementation-defined native_handle_type; // See 30.2.3
  //     native_handle_type native_handle(); // See 30.2.3
};

#  if _LIBCPP_STD_VER >= 17
class _LIBCPP_EXPORTED_FROM_ABI
    _LIBCPP_AVAILABILITY_SHARED_MUTEX _LIBCPP_THREAD_SAFETY_ANNOTATION(__capability__("shared_mutex")) shared_mutex {
  __shared_mutex_base __base_;

public:
  _LIBCPP_HIDE_FROM_ABI shared_mutex() : __base_() {}
  _LIBCPP_HIDE_FROM_ABI ~shared_mutex() = default;

  shared_mutex(const shared_mutex&)            = delete;
  shared_mutex& operator=(const shared_mutex&) = delete;

  // Exclusive ownership
  _LIBCPP_HIDE_FROM_ABI void lock() _LIBCPP_THREAD_SAFETY_ANNOTATION(__acquire_capability__()) {
    return __base_.lock();
  }
  _LIBCPP_HIDE_FROM_ABI bool try_lock() _LIBCPP_THREAD_SAFETY_ANNOTATION(__try_acquire_capability__(true)) {
    return __base_.try_lock();
  }
  _LIBCPP_HIDE_FROM_ABI void unlock() _LIBCPP_THREAD_SAFETY_ANNOTATION(__release_capability__()) {
    return __base_.unlock();
  }

  // Shared ownership
  _LIBCPP_HIDE_FROM_ABI void lock_shared() _LIBCPP_THREAD_SAFETY_ANNOTATION(__acquire_shared_capability__()) {
    return __base_.lock_shared();
  }
  _LIBCPP_HIDE_FROM_ABI bool try_lock_shared()
      _LIBCPP_THREAD_SAFETY_ANNOTATION(__try_acquire_shared_capability__(true)) {
    return __base_.try_lock_shared();
  }
  _LIBCPP_HIDE_FROM_ABI void unlock_shared() _LIBCPP_THREAD_SAFETY_ANNOTATION(__release_shared_capability__()) {
    return __base_.unlock_shared();
  }

  //     typedef __shared_mutex_base::native_handle_type native_handle_type;
  //     _LIBCPP_HIDE_FROM_ABI native_handle_type native_handle() { return __base::unlock_shared(); }
};
#  endif

class _LIBCPP_EXPORTED_FROM_ABI _LIBCPP_AVAILABILITY_SHARED_MUTEX _LIBCPP_THREAD_SAFETY_ANNOTATION(
    __capability__("shared_timed_mutex")) shared_timed_mutex {
  __shared_mutex_base __base_;

public:
  shared_timed_mutex();
  _LIBCPP_HIDE_FROM_ABI ~shared_timed_mutex() = default;

  shared_timed_mutex(const shared_timed_mutex&)            = delete;
  shared_timed_mutex& operator=(const shared_timed_mutex&) = delete;

  // Exclusive ownership
  void lock() _LIBCPP_THREAD_SAFETY_ANNOTATION(__acquire_capability__());
  bool try_lock() _LIBCPP_THREAD_SAFETY_ANNOTATION(__try_acquire_capability__(true));
  template <class _Rep, class _Period>
  _LIBCPP_HIDE_FROM_ABI bool try_lock_for(const chrono::duration<_Rep, _Period>& __rel_time)
      _LIBCPP_THREAD_SAFETY_ANNOTATION(__try_acquire_capability__(true)) {
    return try_lock_until(chrono::steady_clock::now() + __rel_time);
  }
  template <class _Clock, class _Duration>
  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS bool
  try_lock_until(const chrono::time_point<_Clock, _Duration>& __abs_time)
      _LIBCPP_THREAD_SAFETY_ANNOTATION(__try_acquire_capability__(true));
  void unlock() _LIBCPP_THREAD_SAFETY_ANNOTATION(__release_capability__());

  // Shared ownership
  void lock_shared() _LIBCPP_THREAD_SAFETY_ANNOTATION(__acquire_shared_capability__());
  bool try_lock_shared() _LIBCPP_THREAD_SAFETY_ANNOTATION(__try_acquire_shared_capability__(true));
  template <class _Rep, class _Period>
  _LIBCPP_HIDE_FROM_ABI bool try_lock_shared_for(const chrono::duration<_Rep, _Period>& __rel_time)
      _LIBCPP_THREAD_SAFETY_ANNOTATION(__try_acquire_shared_capability__(true)) {
    return try_lock_shared_until(chrono::steady_clock::now() + __rel_time);
  }
  template <class _Clock, class _Duration>
  _LIBCPP_METHOD_TEMPLATE_IMPLICIT_INSTANTIATION_VIS bool
  try_lock_shared_until(const chrono::time_point<_Clock, _Duration>& __abs_time)
      _LIBCPP_THREAD_SAFETY_ANNOTATION(__try_acquire_shared_capability__(true));
  void unlock_shared() _LIBCPP_THREAD_SAFETY_ANNOTATION(__release_shared_capability__());
};

template <class _Clock, class _Duration>
bool shared_timed_mutex::try_lock_until(const chrono::time_point<_Clock, _Duration>& __abs_time) {
  unique_lock<mutex> __lk(__base_.__mut_);
  if (__base_.__state_ & __base_.__write_entered_) {
    while (true) {
      cv_status __status = __base_.__gate1_.wait_until(__lk, __abs_time);
      if ((__base_.__state_ & __base_.__write_entered_) == 0)
        break;
      if (__status == cv_status::timeout)
        return false;
    }
  }
  __base_.__state_ |= __base_.__write_entered_;
  if (__base_.__state_ & __base_.__n_readers_) {
    while (true) {
      cv_status __status = __base_.__gate2_.wait_until(__lk, __abs_time);
      if ((__base_.__state_ & __base_.__n_readers_) == 0)
        break;
      if (__status == cv_status::timeout) {
        __base_.__state_ &= ~__base_.__write_entered_;
        __base_.__gate1_.notify_all();
        return false;
      }
    }
  }
  return true;
}

template <class _Clock, class _Duration>
bool shared_timed_mutex::try_lock_shared_until(const chrono::time_point<_Clock, _Duration>& __abs_time) {
  unique_lock<mutex> __lk(__base_.__mut_);
  if ((__base_.__state_ & __base_.__write_entered_) ||
      (__base_.__state_ & __base_.__n_readers_) == __base_.__n_readers_) {
    while (true) {
      cv_status __status = __base_.__gate1_.wait_until(__lk, __abs_time);
      if ((__base_.__state_ & __base_.__write_entered_) == 0 &&
          (__base_.__state_ & __base_.__n_readers_) < __base_.__n_readers_)
        break;
      if (__status == cv_status::timeout)
        return false;
    }
  }
  unsigned __num_readers = (__base_.__state_ & __base_.__n_readers_) + 1;
  __base_.__state_ &= ~__base_.__n_readers_;
  __base_.__state_ |= __num_readers;
  return true;
}

template <class _Mutex>
class shared_lock {
public:
  typedef _Mutex mutex_type;

private:
  mutex_type* __m_;
  bool __owns_;

public:
  _LIBCPP_HIDE_FROM_ABI shared_lock() _NOEXCEPT : __m_(nullptr), __owns_(false) {}

  _LIBCPP_HIDE_FROM_ABI explicit shared_lock(mutex_type& __m) : __m_(_VSTD::addressof(__m)), __owns_(true) {
    __m_->lock_shared();
  }

  _LIBCPP_HIDE_FROM_ABI shared_lock(mutex_type& __m, defer_lock_t) _NOEXCEPT
      : __m_(_VSTD::addressof(__m)),
        __owns_(false) {}

  _LIBCPP_HIDE_FROM_ABI shared_lock(mutex_type& __m, try_to_lock_t)
      : __m_(_VSTD::addressof(__m)), __owns_(__m.try_lock_shared()) {}

  _LIBCPP_HIDE_FROM_ABI shared_lock(mutex_type& __m, adopt_lock_t) : __m_(_VSTD::addressof(__m)), __owns_(true) {}

  template <class _Clock, class _Duration>
  _LIBCPP_HIDE_FROM_ABI shared_lock(mutex_type& __m, const chrono::time_point<_Clock, _Duration>& __abs_time)
      : __m_(_VSTD::addressof(__m)), __owns_(__m.try_lock_shared_until(__abs_time)) {}

  template <class _Rep, class _Period>
  _LIBCPP_HIDE_FROM_ABI shared_lock(mutex_type& __m, const chrono::duration<_Rep, _Period>& __rel_time)
      : __m_(_VSTD::addressof(__m)), __owns_(__m.try_lock_shared_for(__rel_time)) {}

  _LIBCPP_HIDE_FROM_ABI ~shared_lock() {
    if (__owns_)
      __m_->unlock_shared();
  }

  shared_lock(shared_lock const&)            = delete;
  shared_lock& operator=(shared_lock const&) = delete;

  _LIBCPP_HIDE_FROM_ABI shared_lock(shared_lock&& __u) _NOEXCEPT : __m_(__u.__m_), __owns_(__u.__owns_) {
    __u.__m_    = nullptr;
    __u.__owns_ = false;
  }

  _LIBCPP_HIDE_FROM_ABI shared_lock& operator=(shared_lock&& __u) _NOEXCEPT {
    if (__owns_)
      __m_->unlock_shared();
    __m_        = nullptr;
    __owns_     = false;
    __m_        = __u.__m_;
    __owns_     = __u.__owns_;
    __u.__m_    = nullptr;
    __u.__owns_ = false;
    return *this;
  }

  _LIBCPP_HIDE_FROM_ABI void lock();
  _LIBCPP_HIDE_FROM_ABI bool try_lock();
  template <class _Rep, class _Period>
  _LIBCPP_HIDE_FROM_ABI bool try_lock_for(const chrono::duration<_Rep, _Period>& __rel_time);
  template <class _Clock, class _Duration>
  _LIBCPP_HIDE_FROM_ABI bool try_lock_until(const chrono::time_point<_Clock, _Duration>& __abs_time);
  _LIBCPP_HIDE_FROM_ABI void unlock();

  // Setters
  _LIBCPP_HIDE_FROM_ABI void swap(shared_lock& __u) _NOEXCEPT {
    _VSTD::swap(__m_, __u.__m_);
    _VSTD::swap(__owns_, __u.__owns_);
  }

  _LIBCPP_HIDE_FROM_ABI mutex_type* release() _NOEXCEPT {
    mutex_type* __m = __m_;
    __m_            = nullptr;
    __owns_         = false;
    return __m;
  }

  // Getters
  _LIBCPP_HIDE_FROM_ABI bool owns_lock() const _NOEXCEPT { return __owns_; }

  _LIBCPP_HIDE_FROM_ABI explicit operator bool() const _NOEXCEPT { return __owns_; }

  _LIBCPP_HIDE_FROM_ABI mutex_type* mutex() const _NOEXCEPT { return __m_; }
};
_LIBCPP_CTAD_SUPPORTED_FOR_TYPE(shared_lock);

template <class _Mutex>
void shared_lock<_Mutex>::lock() {
  if (__m_ == nullptr)
    __throw_system_error(EPERM, "shared_lock::lock: references null mutex");
  if (__owns_)
    __throw_system_error(EDEADLK, "shared_lock::lock: already locked");
  __m_->lock_shared();
  __owns_ = true;
}

template <class _Mutex>
bool shared_lock<_Mutex>::try_lock() {
  if (__m_ == nullptr)
    __throw_system_error(EPERM, "shared_lock::try_lock: references null mutex");
  if (__owns_)
    __throw_system_error(EDEADLK, "shared_lock::try_lock: already locked");
  __owns_ = __m_->try_lock_shared();
  return __owns_;
}

template <class _Mutex>
template <class _Rep, class _Period>
bool shared_lock<_Mutex>::try_lock_for(const chrono::duration<_Rep, _Period>& __d) {
  if (__m_ == nullptr)
    __throw_system_error(EPERM, "shared_lock::try_lock_for: references null mutex");
  if (__owns_)
    __throw_system_error(EDEADLK, "shared_lock::try_lock_for: already locked");
  __owns_ = __m_->try_lock_shared_for(__d);
  return __owns_;
}

template <class _Mutex>
template <class _Clock, class _Duration>
bool shared_lock<_Mutex>::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t) {
  if (__m_ == nullptr)
    __throw_system_error(EPERM, "shared_lock::try_lock_until: references null mutex");
  if (__owns_)
    __throw_system_error(EDEADLK, "shared_lock::try_lock_until: already locked");
  __owns_ = __m_->try_lock_shared_until(__t);
  return __owns_;
}

template <class _Mutex>
void shared_lock<_Mutex>::unlock() {
  if (!__owns_)
    __throw_system_error(EPERM, "shared_lock::unlock: not locked");
  __m_->unlock_shared();
  __owns_ = false;
}

template <class _Mutex>
inline _LIBCPP_HIDE_FROM_ABI void swap(shared_lock<_Mutex>& __x, shared_lock<_Mutex>& __y) _NOEXCEPT {
  __x.swap(__y);
}

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP_STD_VER >= 14

_LIBCPP_POP_MACROS

#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
#  include <system_error>
#endif

#endif // _LIBCPP_SHARED_MUTEX