| // -*- C++ -*- |
| //===------------------------ shared_mutex --------------------------------===// |
| // |
| // 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 <__availability> |
| #include <__config> |
| #include <version> |
| |
| _LIBCPP_PUSH_MACROS |
| #include <__undef_macros> |
| |
| |
| #if _LIBCPP_STD_VER > 11 || defined(_LIBCPP_BUILDING_LIBRARY) |
| |
| #include <__mutex_base> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| #pragma GCC system_header |
| #endif |
| |
| #ifdef _LIBCPP_HAS_NO_THREADS |
| #error <shared_mutex> is not supported on this single threaded system |
| #else // !_LIBCPP_HAS_NO_THREADS |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| struct _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_SHARED_MUTEX _LIBCPP_THREAD_SAFETY_ANNOTATION(capability("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_INLINE_VISIBILITY ~__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() _LIBCPP_THREAD_SAFETY_ANNOTATION(acquire_capability()); // blocking |
| bool try_lock() _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()); // blocking |
| bool try_lock_shared() _LIBCPP_THREAD_SAFETY_ANNOTATION(try_acquire_shared_capability(true)); |
| void unlock_shared() _LIBCPP_THREAD_SAFETY_ANNOTATION(release_shared_capability()); |
| |
| // typedef implementation-defined native_handle_type; // See 30.2.3 |
| // native_handle_type native_handle(); // See 30.2.3 |
| }; |
| |
| |
| #if _LIBCPP_STD_VER > 14 |
| class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_SHARED_MUTEX shared_mutex |
| { |
| __shared_mutex_base __base; |
| public: |
| _LIBCPP_INLINE_VISIBILITY shared_mutex() : __base() {} |
| _LIBCPP_INLINE_VISIBILITY ~shared_mutex() = default; |
| |
| shared_mutex(const shared_mutex&) = delete; |
| shared_mutex& operator=(const shared_mutex&) = delete; |
| |
| // Exclusive ownership |
| _LIBCPP_INLINE_VISIBILITY void lock() { return __base.lock(); } |
| _LIBCPP_INLINE_VISIBILITY bool try_lock() { return __base.try_lock(); } |
| _LIBCPP_INLINE_VISIBILITY void unlock() { return __base.unlock(); } |
| |
| // Shared ownership |
| _LIBCPP_INLINE_VISIBILITY void lock_shared() { return __base.lock_shared(); } |
| _LIBCPP_INLINE_VISIBILITY bool try_lock_shared() { return __base.try_lock_shared(); } |
| _LIBCPP_INLINE_VISIBILITY void unlock_shared() { return __base.unlock_shared(); } |
| |
| // typedef __shared_mutex_base::native_handle_type native_handle_type; |
| // _LIBCPP_INLINE_VISIBILITY native_handle_type native_handle() { return __base::unlock_shared(); } |
| }; |
| #endif |
| |
| |
| class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_SHARED_MUTEX shared_timed_mutex |
| { |
| __shared_mutex_base __base; |
| public: |
| shared_timed_mutex(); |
| _LIBCPP_INLINE_VISIBILITY ~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(); |
| bool try_lock(); |
| template <class _Rep, class _Period> |
| _LIBCPP_INLINE_VISIBILITY |
| bool |
| try_lock_for(const chrono::duration<_Rep, _Period>& __rel_time) |
| { |
| 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); |
| void unlock(); |
| |
| // Shared ownership |
| void lock_shared(); |
| bool try_lock_shared(); |
| template <class _Rep, class _Period> |
| _LIBCPP_INLINE_VISIBILITY |
| bool |
| try_lock_shared_for(const chrono::duration<_Rep, _Period>& __rel_time) |
| { |
| 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); |
| void unlock_shared(); |
| }; |
| |
| 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_INLINE_VISIBILITY |
| shared_lock() _NOEXCEPT |
| : __m_(nullptr), |
| __owns_(false) |
| {} |
| |
| _LIBCPP_INLINE_VISIBILITY |
| explicit shared_lock(mutex_type& __m) |
| : __m_(_VSTD::addressof(__m)), |
| __owns_(true) |
| {__m_->lock_shared();} |
| |
| _LIBCPP_INLINE_VISIBILITY |
| shared_lock(mutex_type& __m, defer_lock_t) _NOEXCEPT |
| : __m_(_VSTD::addressof(__m)), |
| __owns_(false) |
| {} |
| |
| _LIBCPP_INLINE_VISIBILITY |
| shared_lock(mutex_type& __m, try_to_lock_t) |
| : __m_(_VSTD::addressof(__m)), |
| __owns_(__m.try_lock_shared()) |
| {} |
| |
| _LIBCPP_INLINE_VISIBILITY |
| shared_lock(mutex_type& __m, adopt_lock_t) |
| : __m_(_VSTD::addressof(__m)), |
| __owns_(true) |
| {} |
| |
| template <class _Clock, class _Duration> |
| _LIBCPP_INLINE_VISIBILITY |
| 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_INLINE_VISIBILITY |
| 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_INLINE_VISIBILITY |
| ~shared_lock() |
| { |
| if (__owns_) |
| __m_->unlock_shared(); |
| } |
| |
| shared_lock(shared_lock const&) = delete; |
| shared_lock& operator=(shared_lock const&) = delete; |
| |
| _LIBCPP_INLINE_VISIBILITY |
| shared_lock(shared_lock&& __u) _NOEXCEPT |
| : __m_(__u.__m_), |
| __owns_(__u.__owns_) |
| { |
| __u.__m_ = nullptr; |
| __u.__owns_ = false; |
| } |
| |
| _LIBCPP_INLINE_VISIBILITY |
| 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; |
| } |
| |
| void lock(); |
| 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 |
| _LIBCPP_INLINE_VISIBILITY |
| void swap(shared_lock& __u) _NOEXCEPT |
| { |
| _VSTD::swap(__m_, __u.__m_); |
| _VSTD::swap(__owns_, __u.__owns_); |
| } |
| |
| _LIBCPP_INLINE_VISIBILITY |
| mutex_type* release() _NOEXCEPT |
| { |
| mutex_type* __m = __m_; |
| __m_ = nullptr; |
| __owns_ = false; |
| return __m; |
| } |
| |
| // Getters |
| _LIBCPP_INLINE_VISIBILITY |
| bool owns_lock() const _NOEXCEPT {return __owns_;} |
| |
| _LIBCPP_INLINE_VISIBILITY |
| explicit operator bool () const _NOEXCEPT {return __owns_;} |
| |
| _LIBCPP_INLINE_VISIBILITY |
| mutex_type* mutex() const _NOEXCEPT {return __m_;} |
| }; |
| |
| 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_INLINE_VISIBILITY |
| void |
| swap(shared_lock<_Mutex>& __x, shared_lock<_Mutex>& __y) _NOEXCEPT |
| {__x.swap(__y);} |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // !_LIBCPP_HAS_NO_THREADS |
| |
| #endif // _LIBCPP_STD_VER > 11 |
| |
| _LIBCPP_POP_MACROS |
| |
| #endif // _LIBCPP_SHARED_MUTEX |