758 lines
19 KiB
C++
758 lines
19 KiB
C++
// <mutex> -*- C++ -*-
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// Copyright (C) 2003-2015 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 3, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// Under Section 7 of GPL version 3, you are granted additional
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// permissions described in the GCC Runtime Library Exception, version
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// 3.1, as published by the Free Software Foundation.
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// You should have received a copy of the GNU General Public License and
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// a copy of the GCC Runtime Library Exception along with this program;
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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// <http://www.gnu.org/licenses/>.
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/** @file include/mutex
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* This is a Standard C++ Library header.
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*/
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#ifndef _GLIBCXX_MUTEX
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#define _GLIBCXX_MUTEX 1
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#pragma GCC system_header
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#if __cplusplus < 201103L
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# include <bits/c++0x_warning.h>
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#else
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#include <tuple>
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#include <chrono>
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#include <exception>
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#include <type_traits>
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#include <functional>
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#include <system_error>
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#include <bits/functexcept.h>
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#include <bits/gthr.h>
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#include <bits/move.h> // for std::swap
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#include <bits/cxxabi_forced.h>
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#ifdef _GLIBCXX_USE_C99_STDINT_TR1
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namespace std _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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#ifdef _GLIBCXX_HAS_GTHREADS
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// Common base class for std::mutex and std::timed_mutex
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class __mutex_base
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{
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protected:
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typedef __gthread_mutex_t __native_type;
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#ifdef __GTHREAD_MUTEX_INIT
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__native_type _M_mutex = __GTHREAD_MUTEX_INIT;
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constexpr __mutex_base() noexcept = default;
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#else
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__native_type _M_mutex;
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__mutex_base() noexcept
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{
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// XXX EAGAIN, ENOMEM, EPERM, EBUSY(may), EINVAL(may)
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__GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex);
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}
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~__mutex_base() noexcept { __gthread_mutex_destroy(&_M_mutex); }
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#endif
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__mutex_base(const __mutex_base&) = delete;
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__mutex_base& operator=(const __mutex_base&) = delete;
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};
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// Common base class for std::recursive_mutex and std::recursive_timed_mutex
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class __recursive_mutex_base
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{
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protected:
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typedef __gthread_recursive_mutex_t __native_type;
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__recursive_mutex_base(const __recursive_mutex_base&) = delete;
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__recursive_mutex_base& operator=(const __recursive_mutex_base&) = delete;
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#ifdef __GTHREAD_RECURSIVE_MUTEX_INIT
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__native_type _M_mutex = __GTHREAD_RECURSIVE_MUTEX_INIT;
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__recursive_mutex_base() = default;
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#else
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__native_type _M_mutex;
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__recursive_mutex_base()
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{
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// XXX EAGAIN, ENOMEM, EPERM, EBUSY(may), EINVAL(may)
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__GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex);
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}
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~__recursive_mutex_base()
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{ __gthread_recursive_mutex_destroy(&_M_mutex); }
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#endif
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};
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/**
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* @defgroup mutexes Mutexes
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* @ingroup concurrency
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*
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* Classes for mutex support.
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* @{
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*/
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/// The standard mutex type.
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class mutex : private __mutex_base
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{
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public:
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typedef __native_type* native_handle_type;
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#ifdef __GTHREAD_MUTEX_INIT
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constexpr
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#endif
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mutex() noexcept = default;
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~mutex() = default;
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mutex(const mutex&) = delete;
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mutex& operator=(const mutex&) = delete;
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void
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lock()
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{
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int __e = __gthread_mutex_lock(&_M_mutex);
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// EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may)
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if (__e)
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__throw_system_error(__e);
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}
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bool
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try_lock() noexcept
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{
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// XXX EINVAL, EAGAIN, EBUSY
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return !__gthread_mutex_trylock(&_M_mutex);
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}
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void
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unlock()
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{
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// XXX EINVAL, EAGAIN, EPERM
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__gthread_mutex_unlock(&_M_mutex);
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}
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native_handle_type
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native_handle()
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{ return &_M_mutex; }
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};
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/// The standard recursive mutex type.
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class recursive_mutex : private __recursive_mutex_base
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{
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public:
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typedef __native_type* native_handle_type;
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recursive_mutex() = default;
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~recursive_mutex() = default;
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recursive_mutex(const recursive_mutex&) = delete;
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recursive_mutex& operator=(const recursive_mutex&) = delete;
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void
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lock()
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{
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int __e = __gthread_recursive_mutex_lock(&_M_mutex);
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// EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may)
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if (__e)
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__throw_system_error(__e);
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}
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bool
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try_lock() noexcept
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{
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// XXX EINVAL, EAGAIN, EBUSY
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return !__gthread_recursive_mutex_trylock(&_M_mutex);
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}
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void
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unlock()
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{
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// XXX EINVAL, EAGAIN, EBUSY
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__gthread_recursive_mutex_unlock(&_M_mutex);
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}
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native_handle_type
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native_handle()
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{ return &_M_mutex; }
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};
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#if _GTHREAD_USE_MUTEX_TIMEDLOCK
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template<typename _Derived>
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class __timed_mutex_impl
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{
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protected:
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typedef chrono::high_resolution_clock __clock_t;
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template<typename _Rep, typename _Period>
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bool
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_M_try_lock_for(const chrono::duration<_Rep, _Period>& __rtime)
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{
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using chrono::steady_clock;
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auto __rt = chrono::duration_cast<steady_clock::duration>(__rtime);
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if (ratio_greater<steady_clock::period, _Period>())
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++__rt;
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return _M_try_lock_until(steady_clock::now() + __rt);
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}
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template<typename _Duration>
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bool
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_M_try_lock_until(const chrono::time_point<__clock_t,
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_Duration>& __atime)
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{
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auto __s = chrono::time_point_cast<chrono::seconds>(__atime);
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auto __ns = chrono::duration_cast<chrono::nanoseconds>(__atime - __s);
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__gthread_time_t __ts = {
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static_cast<std::time_t>(__s.time_since_epoch().count()),
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static_cast<long>(__ns.count())
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};
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auto __mutex = static_cast<_Derived*>(this)->native_handle();
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return !__gthread_mutex_timedlock(__mutex, &__ts);
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}
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template<typename _Clock, typename _Duration>
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bool
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_M_try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime)
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{
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auto __rtime = __atime - _Clock::now();
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return _M_try_lock_until(__clock_t::now() + __rtime);
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}
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};
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/// The standard timed mutex type.
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class timed_mutex
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: private __mutex_base, public __timed_mutex_impl<timed_mutex>
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{
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public:
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typedef __native_type* native_handle_type;
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timed_mutex() = default;
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~timed_mutex() = default;
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timed_mutex(const timed_mutex&) = delete;
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timed_mutex& operator=(const timed_mutex&) = delete;
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void
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lock()
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{
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int __e = __gthread_mutex_lock(&_M_mutex);
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// EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may)
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if (__e)
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__throw_system_error(__e);
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}
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bool
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try_lock() noexcept
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{
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// XXX EINVAL, EAGAIN, EBUSY
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return !__gthread_mutex_trylock(&_M_mutex);
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}
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template <class _Rep, class _Period>
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bool
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try_lock_for(const chrono::duration<_Rep, _Period>& __rtime)
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{ return _M_try_lock_for(__rtime); }
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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>& __atime)
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{ return _M_try_lock_until(__atime); }
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void
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unlock()
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{
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// XXX EINVAL, EAGAIN, EBUSY
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__gthread_mutex_unlock(&_M_mutex);
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}
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native_handle_type
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native_handle()
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{ return &_M_mutex; }
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};
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/// The standard recursive timed mutex type.
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class recursive_timed_mutex
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: private __recursive_mutex_base,
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public __timed_mutex_impl<recursive_timed_mutex>
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{
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public:
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typedef __native_type* native_handle_type;
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recursive_timed_mutex() = default;
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~recursive_timed_mutex() = default;
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recursive_timed_mutex(const recursive_timed_mutex&) = delete;
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recursive_timed_mutex& operator=(const recursive_timed_mutex&) = delete;
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void
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lock()
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{
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int __e = __gthread_recursive_mutex_lock(&_M_mutex);
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// EINVAL, EAGAIN, EBUSY, EINVAL, EDEADLK(may)
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if (__e)
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__throw_system_error(__e);
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}
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bool
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try_lock() noexcept
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{
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// XXX EINVAL, EAGAIN, EBUSY
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return !__gthread_recursive_mutex_trylock(&_M_mutex);
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}
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template <class _Rep, class _Period>
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bool
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try_lock_for(const chrono::duration<_Rep, _Period>& __rtime)
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{ return _M_try_lock_for(__rtime); }
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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>& __atime)
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{ return _M_try_lock_until(__atime); }
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void
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unlock()
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{
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// XXX EINVAL, EAGAIN, EBUSY
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__gthread_recursive_mutex_unlock(&_M_mutex);
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}
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native_handle_type
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native_handle()
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{ return &_M_mutex; }
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};
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#endif
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#endif // _GLIBCXX_HAS_GTHREADS
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/// Do not acquire ownership of the mutex.
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struct defer_lock_t { };
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/// Try to acquire ownership of the mutex without blocking.
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struct try_to_lock_t { };
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/// Assume the calling thread has already obtained mutex ownership
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/// and manage it.
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struct adopt_lock_t { };
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/// Tag used to prevent a scoped lock from acquiring ownership of a mutex.
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constexpr defer_lock_t defer_lock { };
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/// Tag used to prevent a scoped lock from blocking if a mutex is locked.
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constexpr try_to_lock_t try_to_lock { };
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/// Tag used to make a scoped lock take ownership of a locked mutex.
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constexpr adopt_lock_t adopt_lock { };
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/** @brief A movable scoped lock type.
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*
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* A unique_lock controls mutex ownership within a scope. Ownership of the
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* mutex can be delayed until after construction and can be transferred
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* to another unique_lock by move construction or move assignment. If a
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* mutex lock is owned when the destructor runs ownership will be released.
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*/
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template<typename _Mutex>
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class lock_guard
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{
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public:
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typedef _Mutex mutex_type;
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explicit lock_guard(mutex_type& __m) : _M_device(__m)
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{ _M_device.lock(); }
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lock_guard(mutex_type& __m, adopt_lock_t) : _M_device(__m)
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{ } // calling thread owns mutex
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~lock_guard()
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{ _M_device.unlock(); }
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lock_guard(const lock_guard&) = delete;
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lock_guard& operator=(const lock_guard&) = delete;
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private:
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mutex_type& _M_device;
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};
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/// unique_lock
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template<typename _Mutex>
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class unique_lock
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{
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public:
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typedef _Mutex mutex_type;
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unique_lock() noexcept
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: _M_device(0), _M_owns(false)
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{ }
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explicit unique_lock(mutex_type& __m)
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: _M_device(std::__addressof(__m)), _M_owns(false)
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{
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lock();
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_M_owns = true;
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}
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unique_lock(mutex_type& __m, defer_lock_t) noexcept
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: _M_device(std::__addressof(__m)), _M_owns(false)
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{ }
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unique_lock(mutex_type& __m, try_to_lock_t)
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: _M_device(std::__addressof(__m)), _M_owns(_M_device->try_lock())
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{ }
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unique_lock(mutex_type& __m, adopt_lock_t)
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: _M_device(std::__addressof(__m)), _M_owns(true)
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{
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// XXX calling thread owns mutex
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}
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template<typename _Clock, typename _Duration>
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unique_lock(mutex_type& __m,
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const chrono::time_point<_Clock, _Duration>& __atime)
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: _M_device(std::__addressof(__m)),
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_M_owns(_M_device->try_lock_until(__atime))
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{ }
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template<typename _Rep, typename _Period>
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unique_lock(mutex_type& __m,
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const chrono::duration<_Rep, _Period>& __rtime)
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: _M_device(std::__addressof(__m)),
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_M_owns(_M_device->try_lock_for(__rtime))
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{ }
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~unique_lock()
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{
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if (_M_owns)
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unlock();
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}
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unique_lock(const unique_lock&) = delete;
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unique_lock& operator=(const unique_lock&) = delete;
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unique_lock(unique_lock&& __u) noexcept
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: _M_device(__u._M_device), _M_owns(__u._M_owns)
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{
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__u._M_device = 0;
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__u._M_owns = false;
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}
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unique_lock& operator=(unique_lock&& __u) noexcept
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{
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if(_M_owns)
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unlock();
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unique_lock(std::move(__u)).swap(*this);
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__u._M_device = 0;
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__u._M_owns = false;
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return *this;
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}
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void
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lock()
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{
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if (!_M_device)
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__throw_system_error(int(errc::operation_not_permitted));
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else if (_M_owns)
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__throw_system_error(int(errc::resource_deadlock_would_occur));
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else
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{
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_M_device->lock();
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_M_owns = true;
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}
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}
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bool
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try_lock()
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{
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if (!_M_device)
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__throw_system_error(int(errc::operation_not_permitted));
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else if (_M_owns)
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__throw_system_error(int(errc::resource_deadlock_would_occur));
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else
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{
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_M_owns = _M_device->try_lock();
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return _M_owns;
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}
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}
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template<typename _Clock, typename _Duration>
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bool
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try_lock_until(const chrono::time_point<_Clock, _Duration>& __atime)
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{
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if (!_M_device)
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__throw_system_error(int(errc::operation_not_permitted));
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else if (_M_owns)
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__throw_system_error(int(errc::resource_deadlock_would_occur));
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else
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{
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_M_owns = _M_device->try_lock_until(__atime);
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return _M_owns;
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}
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}
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template<typename _Rep, typename _Period>
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bool
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try_lock_for(const chrono::duration<_Rep, _Period>& __rtime)
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{
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if (!_M_device)
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__throw_system_error(int(errc::operation_not_permitted));
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else if (_M_owns)
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__throw_system_error(int(errc::resource_deadlock_would_occur));
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else
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{
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_M_owns = _M_device->try_lock_for(__rtime);
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return _M_owns;
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}
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}
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void
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unlock()
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{
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if (!_M_owns)
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__throw_system_error(int(errc::operation_not_permitted));
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else if (_M_device)
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{
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_M_device->unlock();
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_M_owns = false;
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}
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}
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void
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swap(unique_lock& __u) noexcept
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{
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std::swap(_M_device, __u._M_device);
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std::swap(_M_owns, __u._M_owns);
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}
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mutex_type*
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release() noexcept
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{
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mutex_type* __ret = _M_device;
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|
_M_device = 0;
|
|
_M_owns = false;
|
|
return __ret;
|
|
}
|
|
|
|
bool
|
|
owns_lock() const noexcept
|
|
{ return _M_owns; }
|
|
|
|
explicit operator bool() const noexcept
|
|
{ return owns_lock(); }
|
|
|
|
mutex_type*
|
|
mutex() const noexcept
|
|
{ return _M_device; }
|
|
|
|
private:
|
|
mutex_type* _M_device;
|
|
bool _M_owns; // XXX use atomic_bool
|
|
};
|
|
|
|
/// Swap overload for unique_lock objects.
|
|
template<typename _Mutex>
|
|
inline void
|
|
swap(unique_lock<_Mutex>& __x, unique_lock<_Mutex>& __y) noexcept
|
|
{ __x.swap(__y); }
|
|
|
|
template<typename _Lock>
|
|
inline unique_lock<_Lock>
|
|
__try_to_lock(_Lock& __l)
|
|
{ return unique_lock<_Lock>{__l, try_to_lock}; }
|
|
|
|
template<int _Idx, bool _Continue = true>
|
|
struct __try_lock_impl
|
|
{
|
|
template<typename... _Lock>
|
|
static void
|
|
__do_try_lock(tuple<_Lock&...>& __locks, int& __idx)
|
|
{
|
|
__idx = _Idx;
|
|
auto __lock = std::__try_to_lock(std::get<_Idx>(__locks));
|
|
if (__lock.owns_lock())
|
|
{
|
|
constexpr bool __cont = _Idx + 2 < sizeof...(_Lock);
|
|
using __try_locker = __try_lock_impl<_Idx + 1, __cont>;
|
|
__try_locker::__do_try_lock(__locks, __idx);
|
|
if (__idx == -1)
|
|
__lock.release();
|
|
}
|
|
}
|
|
};
|
|
|
|
template<int _Idx>
|
|
struct __try_lock_impl<_Idx, false>
|
|
{
|
|
template<typename... _Lock>
|
|
static void
|
|
__do_try_lock(tuple<_Lock&...>& __locks, int& __idx)
|
|
{
|
|
__idx = _Idx;
|
|
auto __lock = std::__try_to_lock(std::get<_Idx>(__locks));
|
|
if (__lock.owns_lock())
|
|
{
|
|
__idx = -1;
|
|
__lock.release();
|
|
}
|
|
}
|
|
};
|
|
|
|
/** @brief Generic try_lock.
|
|
* @param __l1 Meets Mutex requirements (try_lock() may throw).
|
|
* @param __l2 Meets Mutex requirements (try_lock() may throw).
|
|
* @param __l3 Meets Mutex requirements (try_lock() may throw).
|
|
* @return Returns -1 if all try_lock() calls return true. Otherwise returns
|
|
* a 0-based index corresponding to the argument that returned false.
|
|
* @post Either all arguments are locked, or none will be.
|
|
*
|
|
* Sequentially calls try_lock() on each argument.
|
|
*/
|
|
template<typename _Lock1, typename _Lock2, typename... _Lock3>
|
|
int
|
|
try_lock(_Lock1& __l1, _Lock2& __l2, _Lock3&... __l3)
|
|
{
|
|
int __idx;
|
|
auto __locks = std::tie(__l1, __l2, __l3...);
|
|
__try_lock_impl<0>::__do_try_lock(__locks, __idx);
|
|
return __idx;
|
|
}
|
|
|
|
/** @brief Generic lock.
|
|
* @param __l1 Meets Mutex requirements (try_lock() may throw).
|
|
* @param __l2 Meets Mutex requirements (try_lock() may throw).
|
|
* @param __l3 Meets Mutex requirements (try_lock() may throw).
|
|
* @throw An exception thrown by an argument's lock() or try_lock() member.
|
|
* @post All arguments are locked.
|
|
*
|
|
* All arguments are locked via a sequence of calls to lock(), try_lock()
|
|
* and unlock(). If the call exits via an exception any locks that were
|
|
* obtained will be released.
|
|
*/
|
|
template<typename _L1, typename _L2, typename... _L3>
|
|
void
|
|
lock(_L1& __l1, _L2& __l2, _L3&... __l3)
|
|
{
|
|
while (true)
|
|
{
|
|
using __try_locker = __try_lock_impl<0, sizeof...(_L3) != 0>;
|
|
unique_lock<_L1> __first(__l1);
|
|
int __idx;
|
|
auto __locks = std::tie(__l2, __l3...);
|
|
__try_locker::__do_try_lock(__locks, __idx);
|
|
if (__idx == -1)
|
|
{
|
|
__first.release();
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
#ifdef _GLIBCXX_HAS_GTHREADS
|
|
/// once_flag
|
|
struct once_flag
|
|
{
|
|
private:
|
|
typedef __gthread_once_t __native_type;
|
|
__native_type _M_once = __GTHREAD_ONCE_INIT;
|
|
|
|
public:
|
|
/// Constructor
|
|
constexpr once_flag() noexcept = default;
|
|
|
|
/// Deleted copy constructor
|
|
once_flag(const once_flag&) = delete;
|
|
/// Deleted assignment operator
|
|
once_flag& operator=(const once_flag&) = delete;
|
|
|
|
template<typename _Callable, typename... _Args>
|
|
friend void
|
|
call_once(once_flag& __once, _Callable&& __f, _Args&&... __args);
|
|
};
|
|
|
|
#ifdef _GLIBCXX_HAVE_TLS
|
|
extern __thread void* __once_callable;
|
|
extern __thread void (*__once_call)();
|
|
|
|
template<typename _Callable>
|
|
inline void
|
|
__once_call_impl()
|
|
{
|
|
(*(_Callable*)__once_callable)();
|
|
}
|
|
#else
|
|
extern function<void()> __once_functor;
|
|
|
|
extern void
|
|
__set_once_functor_lock_ptr(unique_lock<mutex>*);
|
|
|
|
extern mutex&
|
|
__get_once_mutex();
|
|
#endif
|
|
|
|
extern "C" void __once_proxy(void);
|
|
|
|
/// call_once
|
|
template<typename _Callable, typename... _Args>
|
|
void
|
|
call_once(once_flag& __once, _Callable&& __f, _Args&&... __args)
|
|
{
|
|
#ifdef _GLIBCXX_HAVE_TLS
|
|
auto __bound_functor = std::__bind_simple(std::forward<_Callable>(__f),
|
|
std::forward<_Args>(__args)...);
|
|
__once_callable = std::__addressof(__bound_functor);
|
|
__once_call = &__once_call_impl<decltype(__bound_functor)>;
|
|
#else
|
|
unique_lock<mutex> __functor_lock(__get_once_mutex());
|
|
auto __callable = std::__bind_simple(std::forward<_Callable>(__f),
|
|
std::forward<_Args>(__args)...);
|
|
__once_functor = [&]() { __callable(); };
|
|
__set_once_functor_lock_ptr(&__functor_lock);
|
|
#endif
|
|
|
|
int __e = __gthread_once(&__once._M_once, &__once_proxy);
|
|
|
|
#ifndef _GLIBCXX_HAVE_TLS
|
|
if (__functor_lock)
|
|
__set_once_functor_lock_ptr(0);
|
|
#endif
|
|
|
|
if (__e)
|
|
__throw_system_error(__e);
|
|
}
|
|
#endif // _GLIBCXX_HAS_GTHREADS
|
|
|
|
// @} group mutexes
|
|
_GLIBCXX_END_NAMESPACE_VERSION
|
|
} // namespace
|
|
#endif // _GLIBCXX_USE_C99_STDINT_TR1
|
|
|
|
#endif // C++11
|
|
|
|
#endif // _GLIBCXX_MUTEX
|