316 lines
7.4 KiB
C++
316 lines
7.4 KiB
C++
// Support for concurrent programing -*- C++ -*-
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// Copyright (C) 2003-2021 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 ext/concurrence.h
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* This file is a GNU extension to the Standard C++ Library.
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*/
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#ifndef _CONCURRENCE_H
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#define _CONCURRENCE_H 1
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#pragma GCC system_header
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#include <exception>
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#include <bits/gthr.h>
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#include <bits/functexcept.h>
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#include <bits/cpp_type_traits.h>
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#include <ext/type_traits.h>
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namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
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{
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_GLIBCXX_BEGIN_NAMESPACE_VERSION
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// Available locking policies:
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// _S_single single-threaded code that doesn't need to be locked.
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// _S_mutex multi-threaded code that requires additional support
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// from gthr.h or abstraction layers in concurrence.h.
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// _S_atomic multi-threaded code using atomic operations.
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enum _Lock_policy { _S_single, _S_mutex, _S_atomic };
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// Compile time constant that indicates prefered locking policy in
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// the current configuration.
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static const _Lock_policy __default_lock_policy =
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#ifndef __GTHREADS
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_S_single;
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#elif defined _GLIBCXX_HAVE_ATOMIC_LOCK_POLICY
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_S_atomic;
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#else
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_S_mutex;
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#endif
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// NB: As this is used in libsupc++, need to only depend on
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// exception. No stdexception classes, no use of std::string.
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class __concurrence_lock_error : public std::exception
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{
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public:
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virtual char const*
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what() const throw()
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{ return "__gnu_cxx::__concurrence_lock_error"; }
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};
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class __concurrence_unlock_error : public std::exception
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{
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public:
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virtual char const*
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what() const throw()
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{ return "__gnu_cxx::__concurrence_unlock_error"; }
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};
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class __concurrence_broadcast_error : public std::exception
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{
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public:
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virtual char const*
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what() const throw()
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{ return "__gnu_cxx::__concurrence_broadcast_error"; }
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};
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class __concurrence_wait_error : public std::exception
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{
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public:
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virtual char const*
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what() const throw()
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{ return "__gnu_cxx::__concurrence_wait_error"; }
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};
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// Substitute for concurrence_error object in the case of -fno-exceptions.
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inline void
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__throw_concurrence_lock_error()
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{ _GLIBCXX_THROW_OR_ABORT(__concurrence_lock_error()); }
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inline void
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__throw_concurrence_unlock_error()
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{ _GLIBCXX_THROW_OR_ABORT(__concurrence_unlock_error()); }
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#ifdef __GTHREAD_HAS_COND
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inline void
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__throw_concurrence_broadcast_error()
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{ _GLIBCXX_THROW_OR_ABORT(__concurrence_broadcast_error()); }
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inline void
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__throw_concurrence_wait_error()
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{ _GLIBCXX_THROW_OR_ABORT(__concurrence_wait_error()); }
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#endif
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class __mutex
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{
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private:
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#if __GTHREADS && defined __GTHREAD_MUTEX_INIT
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__gthread_mutex_t _M_mutex = __GTHREAD_MUTEX_INIT;
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#else
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__gthread_mutex_t _M_mutex;
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#endif
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__mutex(const __mutex&);
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__mutex& operator=(const __mutex&);
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public:
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__mutex()
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{
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#if __GTHREADS && ! defined __GTHREAD_MUTEX_INIT
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if (__gthread_active_p())
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__GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex);
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#endif
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}
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#if __GTHREADS && ! defined __GTHREAD_MUTEX_INIT
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~__mutex()
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{
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if (__gthread_active_p())
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__gthread_mutex_destroy(&_M_mutex);
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}
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#endif
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void lock()
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{
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#if __GTHREADS
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if (__gthread_active_p())
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{
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if (__gthread_mutex_lock(&_M_mutex) != 0)
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__throw_concurrence_lock_error();
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}
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#endif
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}
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void unlock()
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{
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#if __GTHREADS
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if (__gthread_active_p())
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{
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if (__gthread_mutex_unlock(&_M_mutex) != 0)
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__throw_concurrence_unlock_error();
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}
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#endif
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}
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__gthread_mutex_t* gthread_mutex(void)
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{ return &_M_mutex; }
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};
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class __recursive_mutex
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{
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private:
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#if __GTHREADS && defined __GTHREAD_RECURSIVE_MUTEX_INIT
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__gthread_recursive_mutex_t _M_mutex = __GTHREAD_RECURSIVE_MUTEX_INIT;
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#else
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__gthread_recursive_mutex_t _M_mutex;
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#endif
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__recursive_mutex(const __recursive_mutex&);
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__recursive_mutex& operator=(const __recursive_mutex&);
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public:
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__recursive_mutex()
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{
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#if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT
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if (__gthread_active_p())
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__GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex);
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#endif
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}
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#if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT
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~__recursive_mutex()
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{
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if (__gthread_active_p())
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__gthread_recursive_mutex_destroy(&_M_mutex);
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}
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#endif
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void lock()
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{
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#if __GTHREADS
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if (__gthread_active_p())
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{
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if (__gthread_recursive_mutex_lock(&_M_mutex) != 0)
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__throw_concurrence_lock_error();
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}
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#endif
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}
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void unlock()
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{
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#if __GTHREADS
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if (__gthread_active_p())
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{
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if (__gthread_recursive_mutex_unlock(&_M_mutex) != 0)
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__throw_concurrence_unlock_error();
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}
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#endif
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}
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__gthread_recursive_mutex_t* gthread_recursive_mutex(void)
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{ return &_M_mutex; }
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};
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/// Scoped lock idiom.
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// Acquire the mutex here with a constructor call, then release with
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// the destructor call in accordance with RAII style.
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class __scoped_lock
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{
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public:
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typedef __mutex __mutex_type;
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private:
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__mutex_type& _M_device;
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__scoped_lock(const __scoped_lock&);
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__scoped_lock& operator=(const __scoped_lock&);
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public:
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explicit __scoped_lock(__mutex_type& __name) : _M_device(__name)
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{ _M_device.lock(); }
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~__scoped_lock() throw()
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{ _M_device.unlock(); }
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};
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#ifdef __GTHREAD_HAS_COND
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class __cond
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{
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private:
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#if __GTHREADS && defined __GTHREAD_COND_INIT
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__gthread_cond_t _M_cond = __GTHREAD_COND_INIT;
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#else
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__gthread_cond_t _M_cond;
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#endif
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__cond(const __cond&);
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__cond& operator=(const __cond&);
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public:
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__cond()
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{
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#if __GTHREADS && ! defined __GTHREAD_COND_INIT
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if (__gthread_active_p())
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__GTHREAD_COND_INIT_FUNCTION(&_M_cond);
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#endif
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}
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#if __GTHREADS && ! defined __GTHREAD_COND_INIT
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~__cond()
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{
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if (__gthread_active_p())
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__gthread_cond_destroy(&_M_cond);
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}
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#endif
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void broadcast()
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{
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#if __GTHREADS
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if (__gthread_active_p())
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{
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if (__gthread_cond_broadcast(&_M_cond) != 0)
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__throw_concurrence_broadcast_error();
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}
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#endif
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}
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void wait(__mutex *mutex)
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{
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#if __GTHREADS
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{
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if (__gthread_cond_wait(&_M_cond, mutex->gthread_mutex()) != 0)
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__throw_concurrence_wait_error();
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}
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#endif
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}
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void wait_recursive(__recursive_mutex *mutex)
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{
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#if __GTHREADS
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{
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if (__gthread_cond_wait_recursive(&_M_cond,
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mutex->gthread_recursive_mutex())
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!= 0)
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__throw_concurrence_wait_error();
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}
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#endif
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}
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};
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#endif
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_GLIBCXX_END_NAMESPACE_VERSION
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} // namespace
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#endif
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