2006-09-14 11:48:15 +02:00
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// Support for concurrent programing -*- C++ -*-
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2007-04-22 12:36:04 +02:00
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// Copyright (C) 2003, 2004, 2005, 2006, 2007
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2006-09-14 11:48:15 +02:00
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// 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 2, 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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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING. If not, write to the Free
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// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
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// USA.
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// As a special exception, you may use this file as part of a free software
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// library without restriction. Specifically, if other files instantiate
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// templates or use macros or inline functions from this file, or you compile
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// this file and link it with other files to produce an executable, this
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// file does not by itself cause the resulting executable to be covered by
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// the GNU General Public License. This exception does not however
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// invalidate any other reasons why the executable file might be covered by
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// the GNU General Public License.
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/** @file concurrence.h
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* This is an internal header file, included by other library headers.
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* You should not attempt to use it directly.
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*/
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#ifndef _CONCURRENCE_H
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#define _CONCURRENCE_H 1
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2006-11-07 19:36:32 +01:00
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#include <exception>
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2006-09-14 11:48:15 +02:00
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#include <bits/gthr.h>
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#include <bits/functexcept.h>
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_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
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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 concurrance.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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#ifdef __GTHREADS
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// NB: This macro doesn't actually exist yet in the compiler, but is
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// set somewhat haphazardly at configure time.
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#ifdef _GLIBCXX_ATOMIC_BUILTINS
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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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#else
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_S_single;
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#endif
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2006-11-07 19:36:32 +01:00
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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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2006-11-12 11:37:00 +01:00
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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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2006-11-12 11:37:00 +01:00
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{ return "__gnu_cxx::__concurrence_lock_error"; }
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};
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2006-11-12 11:37:00 +01:00
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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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// 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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{
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#if __EXCEPTIONS
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throw __concurrence_lock_error();
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#else
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__builtin_abort();
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2006-11-07 19:36:32 +01:00
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#endif
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}
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inline void
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__throw_concurrence_unlock_error()
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{
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#if __EXCEPTIONS
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throw __concurrence_unlock_error();
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#else
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__builtin_abort();
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#endif
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}
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2006-09-14 11:48:15 +02:00
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class __mutex
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{
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private:
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__gthread_mutex_t _M_mutex;
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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
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if (__gthread_active_p())
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{
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#if defined __GTHREAD_MUTEX_INIT
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__gthread_mutex_t __tmp = __GTHREAD_MUTEX_INIT;
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_M_mutex = __tmp;
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#else
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__GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex);
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#endif
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}
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#endif
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}
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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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};
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class __recursive_mutex
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{
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private:
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__gthread_recursive_mutex_t _M_mutex;
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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
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if (__gthread_active_p())
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{
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#if defined __GTHREAD_RECURSIVE_MUTEX_INIT
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__gthread_recursive_mutex_t __tmp = __GTHREAD_RECURSIVE_MUTEX_INIT;
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_M_mutex = __tmp;
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#else
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__GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex);
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#endif
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}
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#endif
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}
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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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};
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/// @brief 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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_GLIBCXX_END_NAMESPACE
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#endif
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