// -*- 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 <__config>
#if !defined(_LIBCPP_HAS_NO_THREADS)
# include <__chrono/duration.h>
# include <__chrono/steady_clock.h>
# include <__chrono/time_point.h>
# include <__condition_variable/condition_variable.h>
# 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
_LIBCPP_BEGIN_NAMESPACE_STD
struct _LIBCPP_EXPORTED_FROM_ABI __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_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_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_(std::addressof(__m)), __owns_(true) {
__m_->lock_shared();
}
_LIBCPP_HIDE_FROM_ABI shared_lock(mutex_type& __m, defer_lock_t) _NOEXCEPT
: __m_(std::addressof(__m)),
__owns_(false) {}
_LIBCPP_HIDE_FROM_ABI shared_lock(mutex_type& __m, try_to_lock_t)
: __m_(std::addressof(__m)), __owns_(__m.try_lock_shared()) {}
_LIBCPP_HIDE_FROM_ABI shared_lock(mutex_type& __m, adopt_lock_t) : __m_(std::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_(std::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_(std::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 {
std::swap(__m_, __u.__m_);
std::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
#endif // !defined(_LIBCPP_HAS_NO_THREADS)
#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
# include <system_error>
#endif
#endif // _LIBCPP_SHARED_MUTEX
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