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// -*- C++ -*- |
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//===------------------------ shared_mutex --------------------------------===// |
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// |
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// The LLVM Compiler Infrastructure |
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// |
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// This file is dual licensed under the MIT and the University of Illinois Open |
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// Source Licenses. See LICENSE.TXT for details. |
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// |
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//===----------------------------------------------------------------------===// |
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|
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#ifndef _LIBCPP_SHARED_MUTEX |
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#define _LIBCPP_SHARED_MUTEX |
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|
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/* |
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shared_mutex synopsis |
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|
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// C++1y |
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|
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namespace std |
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{
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|
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class shared_mutex // C++17 |
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{
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public: |
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shared_mutex(); |
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~shared_mutex(); |
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|
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shared_mutex(const shared_mutex&) = delete; |
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shared_mutex& operator=(const shared_mutex&) = delete; |
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|
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// Exclusive ownership |
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void lock(); // blocking |
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bool try_lock(); |
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void unlock(); |
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|
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// Shared ownership |
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void lock_shared(); // blocking |
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bool try_lock_shared(); |
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void unlock_shared(); |
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|
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typedef implementation-defined native_handle_type; // See 30.2.3 |
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native_handle_type native_handle(); // See 30.2.3 |
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}; |
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|
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class shared_timed_mutex |
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{
|
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public: |
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shared_timed_mutex(); |
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~shared_timed_mutex(); |
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|
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shared_timed_mutex(const shared_timed_mutex&) = delete; |
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shared_timed_mutex& operator=(const shared_timed_mutex&) = delete; |
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|
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// Exclusive ownership |
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void lock(); // blocking |
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bool try_lock(); |
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template <class Rep, class Period> |
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bool try_lock_for(const chrono::duration<Rep, Period>& rel_time); |
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template <class Clock, class Duration> |
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bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time); |
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void unlock(); |
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|
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// Shared ownership |
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void lock_shared(); // blocking |
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bool try_lock_shared(); |
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template <class Rep, class Period> |
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bool |
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try_lock_shared_for(const chrono::duration<Rep, Period>& rel_time); |
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template <class Clock, class Duration> |
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bool |
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try_lock_shared_until(const chrono::time_point<Clock, Duration>& abs_time); |
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void unlock_shared(); |
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}; |
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|
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template <class Mutex> |
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class shared_lock |
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{
|
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public: |
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typedef Mutex mutex_type; |
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|
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// Shared locking |
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shared_lock() noexcept; |
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explicit shared_lock(mutex_type& m); // blocking |
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shared_lock(mutex_type& m, defer_lock_t) noexcept; |
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shared_lock(mutex_type& m, try_to_lock_t); |
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shared_lock(mutex_type& m, adopt_lock_t); |
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template <class Clock, class Duration> |
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shared_lock(mutex_type& m, |
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const chrono::time_point<Clock, Duration>& abs_time); |
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template <class Rep, class Period> |
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shared_lock(mutex_type& m, |
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const chrono::duration<Rep, Period>& rel_time); |
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~shared_lock(); |
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|
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shared_lock(shared_lock const&) = delete; |
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shared_lock& operator=(shared_lock const&) = delete; |
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|
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shared_lock(shared_lock&& u) noexcept; |
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shared_lock& operator=(shared_lock&& u) noexcept; |
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|
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void lock(); // blocking |
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bool try_lock(); |
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template <class Rep, class Period> |
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bool try_lock_for(const chrono::duration<Rep, Period>& rel_time); |
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template <class Clock, class Duration> |
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bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time); |
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void unlock(); |
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|
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// Setters |
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void swap(shared_lock& u) noexcept; |
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mutex_type* release() noexcept; |
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|
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// Getters |
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bool owns_lock() const noexcept; |
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explicit operator bool () const noexcept; |
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mutex_type* mutex() const noexcept; |
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}; |
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|
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template <class Mutex> |
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void swap(shared_lock<Mutex>& x, shared_lock<Mutex>& y) noexcept; |
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|
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} // std |
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|
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*/ |
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|
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#include <__config> |
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|
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#if _LIBCPP_STD_VER > 11 || defined(_LIBCPP_BUILDING_SHARED_MUTEX) |
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|
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#include <__mutex_base> |
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|
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#include <__undef_min_max> |
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|
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
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#pragma GCC system_header |
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#endif |
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|
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#ifdef _LIBCPP_HAS_NO_THREADS |
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#error <shared_mutex> is not supported on this single threaded system |
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#else // !_LIBCPP_HAS_NO_THREADS |
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|
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_LIBCPP_BEGIN_NAMESPACE_STD |
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|
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struct _LIBCPP_TYPE_VIS __shared_mutex_base |
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{
|
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mutex __mut_; |
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condition_variable __gate1_; |
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condition_variable __gate2_; |
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unsigned __state_; |
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|
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static const unsigned __write_entered_ = 1U << (sizeof(unsigned)*__CHAR_BIT__ - 1); |
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static const unsigned __n_readers_ = ~__write_entered_; |
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|
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__shared_mutex_base(); |
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_LIBCPP_INLINE_VISIBILITY ~__shared_mutex_base() = default; |
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|
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__shared_mutex_base(const __shared_mutex_base&) = delete; |
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__shared_mutex_base& operator=(const __shared_mutex_base&) = delete; |
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|
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// Exclusive ownership |
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void lock(); // blocking |
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bool try_lock(); |
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void unlock(); |
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|
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// Shared ownership |
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void lock_shared(); // blocking |
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bool try_lock_shared(); |
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void unlock_shared(); |
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|
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// typedef implementation-defined native_handle_type; // See 30.2.3 |
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// native_handle_type native_handle(); // See 30.2.3 |
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}; |
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|
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|
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#if _LIBCPP_STD_VER > 14 |
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class _LIBCPP_TYPE_VIS shared_mutex |
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{
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__shared_mutex_base __base; |
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public: |
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shared_mutex() : __base() {}
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_LIBCPP_INLINE_VISIBILITY ~shared_mutex() = default; |
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|
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shared_mutex(const shared_mutex&) = delete; |
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shared_mutex& operator=(const shared_mutex&) = delete; |
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|
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// Exclusive ownership |
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_LIBCPP_INLINE_VISIBILITY void lock() { return __base.lock(); }
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_LIBCPP_INLINE_VISIBILITY bool try_lock() { return __base.try_lock(); }
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_LIBCPP_INLINE_VISIBILITY void unlock() { return __base.unlock(); }
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|
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// Shared ownership |
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_LIBCPP_INLINE_VISIBILITY void lock_shared() { return __base.lock_shared(); }
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_LIBCPP_INLINE_VISIBILITY bool try_lock_shared() { return __base.try_lock_shared(); }
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_LIBCPP_INLINE_VISIBILITY void unlock_shared() { return __base.unlock_shared(); }
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|
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// typedef __shared_mutex_base::native_handle_type native_handle_type; |
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// _LIBCPP_INLINE_VISIBILITY native_handle_type native_handle() { return __base::unlock_shared(); }
|
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}; |
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#endif |
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|
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|
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class _LIBCPP_TYPE_VIS shared_timed_mutex |
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{
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__shared_mutex_base __base; |
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public: |
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shared_timed_mutex(); |
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_LIBCPP_INLINE_VISIBILITY ~shared_timed_mutex() = default; |
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shared_timed_mutex(const shared_timed_mutex&) = delete; |
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shared_timed_mutex& operator=(const shared_timed_mutex&) = delete; |
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|
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// Exclusive ownership |
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void lock(); |
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bool try_lock(); |
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template <class _Rep, class _Period> |
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_LIBCPP_INLINE_VISIBILITY |
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bool |
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try_lock_for(const chrono::duration<_Rep, _Period>& __rel_time) |
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{
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return try_lock_until(chrono::steady_clock::now() + __rel_time); |
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} |
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template <class _Clock, class _Duration> |
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bool |
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try_lock_until(const chrono::time_point<_Clock, _Duration>& __abs_time); |
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void unlock(); |
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|
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// Shared ownership |
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void lock_shared(); |
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bool try_lock_shared(); |
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template <class _Rep, class _Period> |
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_LIBCPP_INLINE_VISIBILITY |
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bool |
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try_lock_shared_for(const chrono::duration<_Rep, _Period>& __rel_time) |
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{
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return try_lock_shared_until(chrono::steady_clock::now() + __rel_time); |
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} |
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template <class _Clock, class _Duration> |
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bool |
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try_lock_shared_until(const chrono::time_point<_Clock, _Duration>& __abs_time); |
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void unlock_shared(); |
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}; |
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|
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template <class _Clock, class _Duration> |
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bool |
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shared_timed_mutex::try_lock_until( |
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const chrono::time_point<_Clock, _Duration>& __abs_time) |
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{
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unique_lock<mutex> __lk(__base.__mut_); |
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if (__base.__state_ & __base.__write_entered_) |
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{
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while (true) |
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{
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cv_status __status = __base.__gate1_.wait_until(__lk, __abs_time); |
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if ((__base.__state_ & __base.__write_entered_) == 0) |
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break; |
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if (__status == cv_status::timeout) |
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return false; |
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} |
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} |
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__base.__state_ |= __base.__write_entered_; |
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if (__base.__state_ & __base.__n_readers_) |
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{
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while (true) |
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{
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cv_status __status = __base.__gate2_.wait_until(__lk, __abs_time); |
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if ((__base.__state_ & __base.__n_readers_) == 0) |
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break; |
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if (__status == cv_status::timeout) |
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{
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__base.__state_ &= ~__base.__write_entered_; |
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__base.__gate1_.notify_all(); |
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return false; |
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} |
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} |
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} |
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return true; |
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} |
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template <class _Clock, class _Duration> |
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bool |
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shared_timed_mutex::try_lock_shared_until( |
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const chrono::time_point<_Clock, _Duration>& __abs_time) |
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{
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unique_lock<mutex> __lk(__base.__mut_); |
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if ((__base.__state_ & __base.__write_entered_) || (__base.__state_ & __base.__n_readers_) == __base.__n_readers_) |
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{
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while (true) |
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{
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cv_status status = __base.__gate1_.wait_until(__lk, __abs_time); |
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if ((__base.__state_ & __base.__write_entered_) == 0 && |
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(__base.__state_ & __base.__n_readers_) < __base.__n_readers_) |
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break; |
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if (status == cv_status::timeout) |
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return false; |
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} |
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} |
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unsigned __num_readers = (__base.__state_ & __base.__n_readers_) + 1; |
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__base.__state_ &= ~__base.__n_readers_; |
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__base.__state_ |= __num_readers; |
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return true; |
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} |
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|
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template <class _Mutex> |
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class shared_lock |
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{
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public: |
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typedef _Mutex mutex_type; |
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|
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private: |
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mutex_type* __m_; |
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bool __owns_; |
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|
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public: |
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_LIBCPP_INLINE_VISIBILITY |
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shared_lock() _NOEXCEPT |
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: __m_(nullptr), |
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__owns_(false) |
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{}
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|
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_LIBCPP_INLINE_VISIBILITY |
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explicit shared_lock(mutex_type& __m) |
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: __m_(&__m), |
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__owns_(true) |
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{__m_->lock_shared();}
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|
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_LIBCPP_INLINE_VISIBILITY |
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shared_lock(mutex_type& __m, defer_lock_t) _NOEXCEPT |
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: __m_(&__m), |
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__owns_(false) |
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{}
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_LIBCPP_INLINE_VISIBILITY |
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shared_lock(mutex_type& __m, try_to_lock_t) |
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: __m_(&__m), |
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__owns_(__m.try_lock_shared()) |
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{}
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|
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_LIBCPP_INLINE_VISIBILITY |
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shared_lock(mutex_type& __m, adopt_lock_t) |
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: __m_(&__m), |
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__owns_(true) |
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{}
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|
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template <class _Clock, class _Duration> |
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_LIBCPP_INLINE_VISIBILITY |
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shared_lock(mutex_type& __m, |
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const chrono::time_point<_Clock, _Duration>& __abs_time) |
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: __m_(&__m), |
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__owns_(__m.try_lock_shared_until(__abs_time)) |
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{}
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|
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template <class _Rep, class _Period> |
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_LIBCPP_INLINE_VISIBILITY |
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shared_lock(mutex_type& __m, |
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const chrono::duration<_Rep, _Period>& __rel_time) |
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: __m_(&__m), |
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__owns_(__m.try_lock_shared_for(__rel_time)) |
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{}
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|
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_LIBCPP_INLINE_VISIBILITY |
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~shared_lock() |
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{
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if (__owns_) |
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__m_->unlock_shared(); |
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} |
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|
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shared_lock(shared_lock const&) = delete; |
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shared_lock& operator=(shared_lock const&) = delete; |
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|
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_LIBCPP_INLINE_VISIBILITY |
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shared_lock(shared_lock&& __u) _NOEXCEPT |
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: __m_(__u.__m_), |
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__owns_(__u.__owns_) |
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{
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__u.__m_ = nullptr; |
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__u.__owns_ = false; |
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} |
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|
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_LIBCPP_INLINE_VISIBILITY |
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shared_lock& operator=(shared_lock&& __u) _NOEXCEPT |
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{
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if (__owns_) |
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__m_->unlock_shared(); |
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__m_ = nullptr; |
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__owns_ = false; |
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__m_ = __u.__m_; |
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__owns_ = __u.__owns_; |
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__u.__m_ = nullptr; |
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__u.__owns_ = false; |
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return *this; |
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} |
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|
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void lock(); |
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bool try_lock(); |
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template <class Rep, class Period> |
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bool try_lock_for(const chrono::duration<Rep, Period>& rel_time); |
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template <class Clock, class Duration> |
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bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time); |
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void unlock(); |
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|
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// Setters |
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_LIBCPP_INLINE_VISIBILITY |
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void swap(shared_lock& __u) _NOEXCEPT |
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{
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_VSTD::swap(__m_, __u.__m_); |
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_VSTD::swap(__owns_, __u.__owns_); |
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} |
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|
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_LIBCPP_INLINE_VISIBILITY |
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mutex_type* release() _NOEXCEPT |
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{
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mutex_type* __m = __m_; |
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__m_ = nullptr; |
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__owns_ = false; |
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return __m; |
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} |
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|
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// Getters |
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_LIBCPP_INLINE_VISIBILITY |
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bool owns_lock() const _NOEXCEPT {return __owns_;}
|
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|
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_LIBCPP_INLINE_VISIBILITY |
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explicit operator bool () const _NOEXCEPT {return __owns_;}
|
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|
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_LIBCPP_INLINE_VISIBILITY |
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mutex_type* mutex() const _NOEXCEPT {return __m_;}
|
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}; |
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|
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template <class _Mutex> |
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void |
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shared_lock<_Mutex>::lock() |
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{
|
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if (__m_ == nullptr) |
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__throw_system_error(EPERM, "shared_lock::lock: references null mutex"); |
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if (__owns_) |
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__throw_system_error(EDEADLK, "shared_lock::lock: already locked"); |
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__m_->lock_shared(); |
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__owns_ = true; |
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} |
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|
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template <class _Mutex> |
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bool |
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shared_lock<_Mutex>::try_lock() |
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{
|
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if (__m_ == nullptr) |
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__throw_system_error(EPERM, "shared_lock::try_lock: references null mutex"); |
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if (__owns_) |
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__throw_system_error(EDEADLK, "shared_lock::try_lock: already locked"); |
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__owns_ = __m_->try_lock_shared(); |
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return __owns_; |
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} |
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|
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template <class _Mutex> |
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template <class _Rep, class _Period> |
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bool |
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shared_lock<_Mutex>::try_lock_for(const chrono::duration<_Rep, _Period>& __d) |
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{
|
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if (__m_ == nullptr) |
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__throw_system_error(EPERM, "shared_lock::try_lock_for: references null mutex"); |
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if (__owns_) |
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__throw_system_error(EDEADLK, "shared_lock::try_lock_for: already locked"); |
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__owns_ = __m_->try_lock_shared_for(__d); |
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return __owns_; |
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} |
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|
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template <class _Mutex> |
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template <class _Clock, class _Duration> |
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bool |
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shared_lock<_Mutex>::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t) |
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{
|
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if (__m_ == nullptr) |
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__throw_system_error(EPERM, "shared_lock::try_lock_until: references null mutex"); |
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if (__owns_) |
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__throw_system_error(EDEADLK, "shared_lock::try_lock_until: already locked"); |
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__owns_ = __m_->try_lock_shared_until(__t); |
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return __owns_; |
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} |
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|
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template <class _Mutex> |
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void |
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shared_lock<_Mutex>::unlock() |
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{
|
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if (!__owns_) |
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__throw_system_error(EPERM, "shared_lock::unlock: not locked"); |
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__m_->unlock_shared(); |
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__owns_ = false; |
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} |
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|
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template <class _Mutex> |
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inline _LIBCPP_INLINE_VISIBILITY |
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void |
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swap(shared_lock<_Mutex>& __x, shared_lock<_Mutex>& __y) _NOEXCEPT |
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{__x.swap(__y);}
|
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|
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_LIBCPP_END_NAMESPACE_STD |
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|
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#endif // !_LIBCPP_HAS_NO_THREADS |
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|
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#endif // _LIBCPP_STD_VER > 11 |
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|
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#endif // _LIBCPP_SHARED_MUTEX |