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|
//===------------------------- mutex.cpp ----------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#define _LIBCPP_BUILDING_MUTEX
#include "mutex"
#include "limits"
#include "system_error"
#include "cassert"
_LIBCPP_BEGIN_NAMESPACE_STD
const defer_lock_t defer_lock = {};
const try_to_lock_t try_to_lock = {};
const adopt_lock_t adopt_lock = {};
mutex::~mutex()
{
pthread_mutex_destroy(&__m_);
}
void
mutex::lock()
{
int ec = pthread_mutex_lock(&__m_);
if (ec)
__throw_system_error(ec, "mutex lock failed");
}
bool
mutex::try_lock() _NOEXCEPT
{
return pthread_mutex_trylock(&__m_) == 0;
}
void
mutex::unlock() _NOEXCEPT
{
int ec = pthread_mutex_unlock(&__m_);
(void)ec;
assert(ec == 0);
}
// recursive_mutex
recursive_mutex::recursive_mutex()
{
pthread_mutexattr_t attr;
int ec = pthread_mutexattr_init(&attr);
if (ec)
goto fail;
ec = pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
if (ec)
{
pthread_mutexattr_destroy(&attr);
goto fail;
}
ec = pthread_mutex_init(&__m_, &attr);
if (ec)
{
pthread_mutexattr_destroy(&attr);
goto fail;
}
ec = pthread_mutexattr_destroy(&attr);
if (ec)
{
pthread_mutex_destroy(&__m_);
goto fail;
}
return;
fail:
__throw_system_error(ec, "recursive_mutex constructor failed");
}
recursive_mutex::~recursive_mutex()
{
int e = pthread_mutex_destroy(&__m_);
(void)e;
assert(e == 0);
}
void
recursive_mutex::lock()
{
int ec = pthread_mutex_lock(&__m_);
if (ec)
__throw_system_error(ec, "recursive_mutex lock failed");
}
void
recursive_mutex::unlock() _NOEXCEPT
{
int e = pthread_mutex_unlock(&__m_);
(void)e;
assert(e == 0);
}
bool
recursive_mutex::try_lock() _NOEXCEPT
{
return pthread_mutex_trylock(&__m_) == 0;
}
// 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_(0)
{
}
recursive_timed_mutex::~recursive_timed_mutex()
{
lock_guard<mutex> _(__m_);
}
void
recursive_timed_mutex::lock()
{
pthread_t id = pthread_self();
unique_lock<mutex> lk(__m_);
if (pthread_equal(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
{
pthread_t id = pthread_self();
unique_lock<mutex> lk(__m_, try_to_lock);
if (lk.owns_lock() && (__count_ == 0 || pthread_equal(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_ = 0;
lk.unlock();
__cv_.notify_one();
}
}
// 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.
static pthread_mutex_t mut = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t cv = PTHREAD_COND_INITIALIZER;
void
__call_once(volatile unsigned long& flag, void* arg, void(*func)(void*))
{
pthread_mutex_lock(&mut);
while (flag == 1)
pthread_cond_wait(&cv, &mut);
if (flag == 0)
{
#ifndef _LIBCPP_NO_EXCEPTIONS
try
{
#endif // _LIBCPP_NO_EXCEPTIONS
flag = 1;
pthread_mutex_unlock(&mut);
func(arg);
pthread_mutex_lock(&mut);
flag = ~0ul;
pthread_mutex_unlock(&mut);
pthread_cond_broadcast(&cv);
#ifndef _LIBCPP_NO_EXCEPTIONS
}
catch (...)
{
pthread_mutex_lock(&mut);
flag = 0ul;
pthread_mutex_unlock(&mut);
pthread_cond_broadcast(&cv);
throw;
}
#endif // _LIBCPP_NO_EXCEPTIONS
}
else
pthread_mutex_unlock(&mut);
}
_LIBCPP_END_NAMESPACE_STD
|
