condition_variable
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// <condition_variable> -*- C++ -*-
// Copyright (C) 2008-2013 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
/** @file include/condition_variable
* This is a Standard C++ Library header.
*/
#ifndef _GLIBCXX_CONDITION_VARIABLE
#define _GLIBCXX_CONDITION_VARIABLE 1
#pragma GCC system_header
#if __cplusplus < 201103L
# include <bits/c++0x_warning.h>
#else
#include <chrono>
#include <mutex> // unique_lock
#if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1)
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
/**
* @defgroup condition_variables Condition Variables
* @ingroup concurrency
*
* Classes for condition_variable support.
* @{
*/
/// cv_status
enum class cv_status { no_timeout, timeout };
/// condition_variable
class condition_variable
{
typedef chrono::system_clock __clock_t;
typedef __gthread_cond_t __native_type;
#ifdef __GTHREAD_COND_INIT
__native_type _M_cond = __GTHREAD_COND_INIT;
#else
__native_type _M_cond;
#endif
public:
typedef __native_type* native_handle_type;
condition_variable() noexcept;
~condition_variable() noexcept;
condition_variable(const condition_variable&) = delete;
condition_variable& operator=(const condition_variable&) = delete;
void
notify_one() noexcept;
void
notify_all() noexcept;
void
wait(unique_lock<mutex>& __lock);
template<typename _Predicate>
void
wait(unique_lock<mutex>& __lock, _Predicate __p)
{
while (!__p())
wait(__lock);
}
template<typename _Duration>
cv_status
wait_until(unique_lock<mutex>& __lock,
const chrono::time_point<__clock_t, _Duration>& __atime)
{ return __wait_until_impl(__lock, __atime); }
template<typename _Clock, typename _Duration>
cv_status
wait_until(unique_lock<mutex>& __lock,
const chrono::time_point<_Clock, _Duration>& __atime)
{
// DR 887 - Sync unknown clock to known clock.
const typename _Clock::time_point __c_entry = _Clock::now();
const __clock_t::time_point __s_entry = __clock_t::now();
const auto __delta = __atime - __c_entry;
const auto __s_atime = __s_entry + __delta;
return __wait_until_impl(__lock, __s_atime);
}
template<typename _Clock, typename _Duration, typename _Predicate>
bool
wait_until(unique_lock<mutex>& __lock,
const chrono::time_point<_Clock, _Duration>& __atime,
_Predicate __p)
{
while (!__p())
if (wait_until(__lock, __atime) == cv_status::timeout)
return __p();
return true;
}
template<typename _Rep, typename _Period>
cv_status
wait_for(unique_lock<mutex>& __lock,
const chrono::duration<_Rep, _Period>& __rtime)
{ return wait_until(__lock, __clock_t::now() + __rtime); }
template<typename _Rep, typename _Period, typename _Predicate>
bool
wait_for(unique_lock<mutex>& __lock,
const chrono::duration<_Rep, _Period>& __rtime,
_Predicate __p)
{ return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); }
native_handle_type
native_handle()
{ return &_M_cond; }
private:
template<typename _Dur>
cv_status
__wait_until_impl(unique_lock<mutex>& __lock,
const chrono::time_point<__clock_t, _Dur>& __atime)
{
auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
__gthread_time_t __ts =
{
static_cast<std::time_t>(__s.time_since_epoch().count()),
static_cast<long>(__ns.count())
};
__gthread_cond_timedwait(&_M_cond, __lock.mutex()->native_handle(),
&__ts);
return (__clock_t::now() < __atime
? cv_status::no_timeout : cv_status::timeout);
}
};
/// condition_variable_any
// Like above, but mutex is not required to have try_lock.
class condition_variable_any
{
typedef chrono::system_clock __clock_t;
condition_variable _M_cond;
mutex _M_mutex;
// scoped unlock - unlocks in ctor, re-locks in dtor
template<typename _Lock>
struct _Unlock
{
explicit _Unlock(_Lock& __lk) : _M_lock(__lk) { __lk.unlock(); }
~_Unlock() noexcept(false)
{
if (uncaught_exception())
__try { _M_lock.lock(); } __catch(...) { }
else
_M_lock.lock();
}
_Unlock(const _Unlock&) = delete;
_Unlock& operator=(const _Unlock&) = delete;
_Lock& _M_lock;
};
public:
condition_variable_any() noexcept;
~condition_variable_any() noexcept;
condition_variable_any(const condition_variable_any&) = delete;
condition_variable_any& operator=(const condition_variable_any&) = delete;
void
notify_one() noexcept
{
lock_guard<mutex> __lock(_M_mutex);
_M_cond.notify_one();
}
void
notify_all() noexcept
{
lock_guard<mutex> __lock(_M_mutex);
_M_cond.notify_all();
}
template<typename _Lock>
void
wait(_Lock& __lock)
{
unique_lock<mutex> __my_lock(_M_mutex);
_Unlock<_Lock> __unlock(__lock);
// _M_mutex must be unlocked before re-locking __lock so move
// ownership of _M_mutex lock to an object with shorter lifetime.
unique_lock<mutex> __my_lock2(std::move(__my_lock));
_M_cond.wait(__my_lock2);
}
template<typename _Lock, typename _Predicate>
void
wait(_Lock& __lock, _Predicate __p)
{
while (!__p())
wait(__lock);
}
template<typename _Lock, typename _Clock, typename _Duration>
cv_status
wait_until(_Lock& __lock,
const chrono::time_point<_Clock, _Duration>& __atime)
{
unique_lock<mutex> __my_lock(_M_mutex);
_Unlock<_Lock> __unlock(__lock);
// _M_mutex must be unlocked before re-locking __lock so move
// ownership of _M_mutex lock to an object with shorter lifetime.
unique_lock<mutex> __my_lock2(std::move(__my_lock));
return _M_cond.wait_until(__my_lock2, __atime);
}
template<typename _Lock, typename _Clock,
typename _Duration, typename _Predicate>
bool
wait_until(_Lock& __lock,
const chrono::time_point<_Clock, _Duration>& __atime,
_Predicate __p)
{
while (!__p())
if (wait_until(__lock, __atime) == cv_status::timeout)
return __p();
return true;
}
template<typename _Lock, typename _Rep, typename _Period>
cv_status
wait_for(_Lock& __lock, const chrono::duration<_Rep, _Period>& __rtime)
{ return wait_until(__lock, __clock_t::now() + __rtime); }
template<typename _Lock, typename _Rep,
typename _Period, typename _Predicate>
bool
wait_for(_Lock& __lock,
const chrono::duration<_Rep, _Period>& __rtime, _Predicate __p)
{ return wait_until(__lock, __clock_t::now() + __rtime, std::move(__p)); }
};
// @} group condition_variables
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
#endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
#endif // C++11
#endif // _GLIBCXX_CONDITION_VARIABLE