29 #ifndef _GLIBCXX_SHARED_MUTEX 30 #define _GLIBCXX_SHARED_MUTEX 1 32 #pragma GCC system_header 34 #if __cplusplus <= 201103L 43 namespace std _GLIBCXX_VISIBILITY(default)
45 _GLIBCXX_BEGIN_NAMESPACE_VERSION
52 #ifdef _GLIBCXX_USE_C99_STDINT_TR1 53 #ifdef _GLIBCXX_HAS_GTHREADS 55 #define __cpp_lib_shared_timed_mutex 201402 60 #if _GLIBCXX_USE_PTHREAD_RWLOCK_T && _GTHREAD_USE_MUTEX_TIMEDLOCK 61 typedef chrono::system_clock __clock_t;
63 #ifdef PTHREAD_RWLOCK_INITIALIZER 64 pthread_rwlock_t _M_rwlock = PTHREAD_RWLOCK_INITIALIZER;
70 pthread_rwlock_t _M_rwlock;
75 int __ret = pthread_rwlock_init(&_M_rwlock, NULL);
78 else if (__ret == EAGAIN)
79 __throw_system_error(
int(errc::resource_unavailable_try_again));
80 else if (__ret == EPERM)
81 __throw_system_error(
int(errc::operation_not_permitted));
83 _GLIBCXX_DEBUG_ASSERT(__ret == 0);
88 int __ret __attribute((__unused__)) = pthread_rwlock_destroy(&_M_rwlock);
90 _GLIBCXX_DEBUG_ASSERT(__ret == 0);
102 int __ret = pthread_rwlock_wrlock(&_M_rwlock);
103 if (__ret == EDEADLK)
104 __throw_system_error(
int(errc::resource_deadlock_would_occur));
106 _GLIBCXX_DEBUG_ASSERT(__ret == 0);
112 int __ret = pthread_rwlock_trywrlock(&_M_rwlock);
113 if (__ret == EBUSY)
return false;
115 _GLIBCXX_DEBUG_ASSERT(__ret == 0);
119 template<
typename _Rep,
typename _Period>
123 return try_lock_until(__clock_t::now() + __rel_time);
126 template<
typename _Duration>
133 __gthread_time_t __ts =
135 static_cast<std::time_t
>(__s.time_since_epoch().count()),
136 static_cast<long>(__ns.count())
139 int __ret = pthread_rwlock_timedwrlock(&_M_rwlock, &__ts);
142 if (__ret == ETIMEDOUT || __ret == EDEADLK)
145 _GLIBCXX_DEBUG_ASSERT(__ret == 0);
149 template<
typename _Clock,
typename _Duration>
154 const typename _Clock::time_point __c_entry = _Clock::now();
155 const __clock_t::time_point __s_entry = __clock_t::now();
156 const auto __delta = __abs_time - __c_entry;
157 const auto __s_atime = __s_entry + __delta;
158 return try_lock_until(__s_atime);
164 int __ret __attribute((__unused__)) = pthread_rwlock_unlock(&_M_rwlock);
166 _GLIBCXX_DEBUG_ASSERT(__ret == 0);
180 __ret = pthread_rwlock_rdlock(&_M_rwlock);
181 while (__ret == EAGAIN);
182 if (__ret == EDEADLK)
183 __throw_system_error(
int(errc::resource_deadlock_would_occur));
185 _GLIBCXX_DEBUG_ASSERT(__ret == 0);
191 int __ret = pthread_rwlock_tryrdlock(&_M_rwlock);
195 if (__ret == EBUSY || __ret == EAGAIN)
return false;
197 _GLIBCXX_DEBUG_ASSERT(__ret == 0);
201 template<
typename _Rep,
typename _Period>
205 return try_lock_shared_until(__clock_t::now() + __rel_time);
208 template<
typename _Duration>
216 __gthread_time_t __ts =
218 static_cast<std::time_t
>(__s.time_since_epoch().count()),
219 static_cast<long>(__ns.count())
237 __ret = pthread_rwlock_timedrdlock(&_M_rwlock, &__ts);
238 while (__ret == EAGAIN || __ret == EDEADLK);
239 if (__ret == ETIMEDOUT)
242 _GLIBCXX_DEBUG_ASSERT(__ret == 0);
246 template<
typename _Clock,
typename _Duration>
249 _Duration>& __abs_time)
252 const typename _Clock::time_point __c_entry = _Clock::now();
253 const __clock_t::time_point __s_entry = __clock_t::now();
254 const auto __delta = __abs_time - __c_entry;
255 const auto __s_atime = __s_entry + __delta;
256 return try_lock_shared_until(__s_atime);
265 #else // ! (_GLIBCXX_USE_PTHREAD_RWLOCK_T && _GTHREAD_USE_MUTEX_TIMEDLOCK) 268 typedef chrono::system_clock __clock_t;
304 static constexpr
unsigned _S_write_entered
305 = 1U << (
sizeof(unsigned)*__CHAR_BIT__ - 1);
306 static constexpr
unsigned _S_max_readers = ~_S_write_entered;
309 bool _M_write_entered()
const {
return _M_state & _S_write_entered; }
312 unsigned _M_readers()
const {
return _M_state & _S_max_readers; }
319 _GLIBCXX_DEBUG_ASSERT( _M_state == 0 );
332 _M_gate1.wait(__lk, [=]{
return !_M_write_entered(); });
333 _M_state |= _S_write_entered;
335 _M_gate2.wait(__lk, [=]{
return _M_readers() == 0; });
342 if (__lk.owns_lock() && _M_state == 0)
344 _M_state = _S_write_entered;
350 template<
typename _Rep,
typename _Period>
354 return try_lock_until(__clock_t::now() + __rel_time);
357 template<
typename _Clock,
typename _Duration>
362 if (!_M_gate1.wait_until(__lk, __abs_time,
363 [=]{ return !_M_write_entered(); }))
367 _M_state |= _S_write_entered;
368 if (!_M_gate2.wait_until(__lk, __abs_time,
369 [=]{ return _M_readers() == 0; }))
371 _M_state ^= _S_write_entered;
373 _M_gate1.notify_all();
383 _GLIBCXX_DEBUG_ASSERT( _M_write_entered() );
387 _M_gate1.notify_all();
396 _M_gate1.wait(__lk, [=]{
return _M_state < _S_max_readers; });
404 if (!__lk.owns_lock())
406 if (_M_state < _S_max_readers)
414 template<
typename _Rep,
typename _Period>
418 return try_lock_shared_until(__clock_t::now() + __rel_time);
421 template <
typename _Clock,
typename _Duration>
424 _Duration>& __abs_time)
427 if (!_M_gate1.wait_until(__lk, __abs_time,
428 [=]{ return _M_state < _S_max_readers; }))
440 _GLIBCXX_DEBUG_ASSERT( _M_readers() > 0 );
441 auto __prev = _M_state--;
442 if (_M_write_entered())
445 if (_M_readers() == 0)
446 _M_gate2.notify_one();
454 if (__prev == _S_max_readers)
455 _M_gate1.notify_one();
458 #endif // _GLIBCXX_USE_PTHREAD_RWLOCK_T && _GTHREAD_USE_MUTEX_TIMEDLOCK 460 #endif // _GLIBCXX_HAS_GTHREADS 463 template<
typename _Mutex>
467 typedef _Mutex mutex_type;
471 shared_lock() noexcept : _M_pm(
nullptr), _M_owns(
false) { }
474 shared_lock(mutex_type& __m) : _M_pm(&__m), _M_owns(
true)
475 { __m.lock_shared(); }
478 : _M_pm(&__m), _M_owns(
false) { }
481 : _M_pm(&__m), _M_owns(__m.try_lock_shared()) { }
484 : _M_pm(&__m), _M_owns(
true) { }
486 template<
typename _Clock,
typename _Duration>
489 : _M_pm(&__m), _M_owns(__m.try_lock_shared_until(__abs_time)) { }
491 template<
typename _Rep,
typename _Period>
494 : _M_pm(&__m), _M_owns(__m.try_lock_shared_for(__rel_time)) { }
499 _M_pm->unlock_shared();
519 _M_pm->lock_shared();
527 return _M_owns = _M_pm->try_lock_shared();
530 template<
typename _Rep,
typename _Period>
535 return _M_owns = _M_pm->try_lock_shared_for(__rel_time);
538 template<
typename _Clock,
typename _Duration>
543 return _M_owns = _M_pm->try_lock_shared_until(__abs_time);
550 __throw_system_error(
int(errc::resource_deadlock_would_occur));
551 _M_pm->unlock_shared();
560 std::swap(_M_pm, __u._M_pm);
561 std::swap(_M_owns, __u._M_owns);
573 bool owns_lock()
const noexcept {
return _M_owns; }
575 explicit operator bool()
const noexcept {
return _M_owns; }
577 mutex_type*
mutex()
const noexcept {
return _M_pm; }
583 if (_M_pm ==
nullptr)
584 __throw_system_error(
int(errc::operation_not_permitted));
586 __throw_system_error(
int(errc::resource_deadlock_would_occur));
594 template<
typename _Mutex>
599 #endif // _GLIBCXX_USE_C99_STDINT_TR1 602 _GLIBCXX_END_NAMESPACE_VERSION
607 #endif // _GLIBCXX_SHARED_MUTEX
constexpr enable_if< __is_duration< _ToDur >::value, _ToDur >::type duration_cast(const duration< _Rep, _Period > &__d)
duration_cast
void lock(_L1 &__l1, _L2 &__l2, _L3 &... __l3)
Generic lock.
int try_lock(_Lock1 &__l1, _Lock2 &__l2, _Lock3 &... __l3)
Generic try_lock.
A movable scoped lock type.
ISO C++ entities toplevel namespace is std.
Do not acquire ownership of the mutex.
_Tp exchange(_Tp &__obj, _Up &&__new_val)
Assign __new_val to __obj and return its previous value.
Assume the calling thread has already obtained mutex ownership and manage it.
constexpr enable_if< __is_duration< _ToDur >::value, time_point< _Clock, _ToDur > >::type time_point_cast(const time_point< _Clock, _Dur > &__t)
time_point_cast
Try to acquire ownership of the mutex without blocking.
constexpr try_to_lock_t try_to_lock
Tag used to prevent a scoped lock from blocking if a mutex is locked.