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//===------------------------- mutex.cpp ----------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "mutex"
#include "limits"
#include "system_error"
#if !defined(_LIBCPP_ABI_MICROSOFT)
#include "include/atomic_support.h"
#endif
#include "__undef_macros"
#ifndef _LIBCPP_HAS_NO_THREADS
#if defined(__ELF__) && defined(_LIBCPP_LINK_PTHREAD_LIB)
#pragma comment(lib, "pthread")
#endif
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#ifndef _LIBCPP_HAS_NO_THREADS
const defer_lock_t defer_lock{};
const try_to_lock_t try_to_lock{};
const adopt_lock_t adopt_lock{};
// ~mutex is defined elsewhere
void
mutex::lock()
{
int ec = __libcpp_mutex_lock(&__m_);
if (ec)
__throw_system_error(ec, "mutex lock failed");
}
bool
mutex::try_lock() noexcept
{
return __libcpp_mutex_trylock(&__m_);
}
void
mutex::unlock() noexcept
{
int ec = __libcpp_mutex_unlock(&__m_);
(void)ec;
_LIBCPP_ASSERT(ec == 0, "call to mutex::unlock failed");
}
// recursive_mutex
recursive_mutex::recursive_mutex()
{
int ec = __libcpp_recursive_mutex_init(&__m_);
if (ec)
__throw_system_error(ec, "recursive_mutex constructor failed");
}
recursive_mutex::~recursive_mutex()
{
int e = __libcpp_recursive_mutex_destroy(&__m_);
(void)e;
_LIBCPP_ASSERT(e == 0, "call to ~recursive_mutex() failed");
}
void
recursive_mutex::lock()
{
int ec = __libcpp_recursive_mutex_lock(&__m_);
if (ec)
__throw_system_error(ec, "recursive_mutex lock failed");
}
void
recursive_mutex::unlock() noexcept
{
int e = __libcpp_recursive_mutex_unlock(&__m_);
(void)e;
_LIBCPP_ASSERT(e == 0, "call to recursive_mutex::unlock() failed");
}
bool
recursive_mutex::try_lock() noexcept
{
return __libcpp_recursive_mutex_trylock(&__m_);
}
// timed_mutex
timed_mutex::timed_mutex()
: __locked_(false)
{
}
timed_mutex::~timed_mutex()
{
lock_guard<mutex> _(__m_);
}
void
timed_mutex::lock()
{
unique_lock<mutex> lk(__m_);
while (__locked_)
__cv_.wait(lk);
__locked_ = true;
}
bool
timed_mutex::try_lock() noexcept
{
unique_lock<mutex> lk(__m_, try_to_lock);
if (lk.owns_lock() && !__locked_)
{
__locked_ = true;
return true;
}
return false;
}
void
timed_mutex::unlock() noexcept
{
lock_guard<mutex> _(__m_);
__locked_ = false;
__cv_.notify_one();
}
// recursive_timed_mutex
recursive_timed_mutex::recursive_timed_mutex()
: __count_(0),
__id_{}
{
}
recursive_timed_mutex::~recursive_timed_mutex()
{
lock_guard<mutex> _(__m_);
}
void
recursive_timed_mutex::lock()
{
__thread_id id = this_thread::get_id();
unique_lock<mutex> lk(__m_);
if (id ==__id_)
{
if (__count_ == numeric_limits<size_t>::max())
__throw_system_error(EAGAIN, "recursive_timed_mutex lock limit reached");
++__count_;
return;
}
while (__count_ != 0)
__cv_.wait(lk);
__count_ = 1;
__id_ = id;
}
bool
recursive_timed_mutex::try_lock() noexcept
{
__thread_id id = this_thread::get_id();
unique_lock<mutex> lk(__m_, try_to_lock);
if (lk.owns_lock() && (__count_ == 0 || id == __id_))
{
if (__count_ == numeric_limits<size_t>::max())
return false;
++__count_;
__id_ = id;
return true;
}
return false;
}
void
recursive_timed_mutex::unlock() noexcept
{
unique_lock<mutex> lk(__m_);
if (--__count_ == 0)
{
__id_.__reset();
lk.unlock();
__cv_.notify_one();
}
}
#endif // !_LIBCPP_HAS_NO_THREADS
// If dispatch_once_f ever handles C++ exceptions, and if one can get to it
// without illegal macros (unexpected macros not beginning with _UpperCase or
// __lowercase), and if it stops spinning waiting threads, then call_once should
// call into dispatch_once_f instead of here. Relevant radar this code needs to
// keep in sync with: 7741191.
#ifndef _LIBCPP_HAS_NO_THREADS
_LIBCPP_SAFE_STATIC static __libcpp_mutex_t mut = _LIBCPP_MUTEX_INITIALIZER;
_LIBCPP_SAFE_STATIC static __libcpp_condvar_t cv = _LIBCPP_CONDVAR_INITIALIZER;
#endif
#ifdef _LIBCPP_ABI_MICROSOFT
void __call_once(volatile std::atomic<once_flag::_State_type>& flag, void* arg,
void (*func)(void*))
#else
void __call_once(volatile once_flag::_State_type& flag, void* arg,
void (*func)(void*))
#endif
{
#if defined(_LIBCPP_HAS_NO_THREADS)
if (flag == 0)
{
#ifndef _LIBCPP_NO_EXCEPTIONS
try
{
#endif // _LIBCPP_NO_EXCEPTIONS
flag = 1;
func(arg);
flag = ~once_flag::_State_type(0);
#ifndef _LIBCPP_NO_EXCEPTIONS
}
catch (...)
{
flag = 0;
throw;
}
#endif // _LIBCPP_NO_EXCEPTIONS
}
#else // !_LIBCPP_HAS_NO_THREADS
__libcpp_mutex_lock(&mut);
while (flag == 1)
__libcpp_condvar_wait(&cv, &mut);
if (flag == 0)
{
#ifndef _LIBCPP_NO_EXCEPTIONS
try
{
#endif // _LIBCPP_NO_EXCEPTIONS
#ifdef _LIBCPP_ABI_MICROSOFT
flag.store(once_flag::_State_type(1));
#else
__libcpp_relaxed_store(&flag, once_flag::_State_type(1));
#endif
__libcpp_mutex_unlock(&mut);
func(arg);
__libcpp_mutex_lock(&mut);
#ifdef _LIBCPP_ABI_MICROSOFT
flag.store(~once_flag::_State_type(0), memory_order_release);
#else
__libcpp_atomic_store(&flag, ~once_flag::_State_type(0),
_AO_Release);
#endif
__libcpp_mutex_unlock(&mut);
__libcpp_condvar_broadcast(&cv);
#ifndef _LIBCPP_NO_EXCEPTIONS
}
catch (...)
{
__libcpp_mutex_lock(&mut);
#ifdef _LIBCPP_ABI_MICROSOFT
flag.store(once_flag::_State_type(0), memory_order_relaxed);
#else
__libcpp_relaxed_store(&flag, once_flag::_State_type(0));
#endif
__libcpp_mutex_unlock(&mut);
__libcpp_condvar_broadcast(&cv);
throw;
}
#endif // _LIBCPP_NO_EXCEPTIONS
}
else
__libcpp_mutex_unlock(&mut);
#endif // !_LIBCPP_HAS_NO_THREADS
}
_LIBCPP_END_NAMESPACE_STD
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