concurrence.h
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// Support for concurrent programing -*- C++ -*-
// Copyright (C) 2003-2013 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 ext/concurrence.h
* This file is a GNU extension to the Standard C++ Library.
*/
#ifndef _CONCURRENCE_H
#define _CONCURRENCE_H 1
#pragma GCC system_header
#include <exception>
#include <bits/gthr.h>
#include <bits/functexcept.h>
#include <bits/cpp_type_traits.h>
#include <ext/type_traits.h>
namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
// Available locking policies:
// _S_single single-threaded code that doesn't need to be locked.
// _S_mutex multi-threaded code that requires additional support
// from gthr.h or abstraction layers in concurrence.h.
// _S_atomic multi-threaded code using atomic operations.
enum _Lock_policy { _S_single, _S_mutex, _S_atomic };
// Compile time constant that indicates prefered locking policy in
// the current configuration.
static const _Lock_policy __default_lock_policy =
#ifdef __GTHREADS
#if (defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2) \
&& defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4))
_S_atomic;
#else
_S_mutex;
#endif
#else
_S_single;
#endif
// NB: As this is used in libsupc++, need to only depend on
// exception. No stdexception classes, no use of std::string.
class __concurrence_lock_error : public std::exception
{
public:
virtual char const*
what() const throw()
{ return "__gnu_cxx::__concurrence_lock_error"; }
};
class __concurrence_unlock_error : public std::exception
{
public:
virtual char const*
what() const throw()
{ return "__gnu_cxx::__concurrence_unlock_error"; }
};
class __concurrence_broadcast_error : public std::exception
{
public:
virtual char const*
what() const throw()
{ return "__gnu_cxx::__concurrence_broadcast_error"; }
};
class __concurrence_wait_error : public std::exception
{
public:
virtual char const*
what() const throw()
{ return "__gnu_cxx::__concurrence_wait_error"; }
};
// Substitute for concurrence_error object in the case of -fno-exceptions.
inline void
__throw_concurrence_lock_error()
{ _GLIBCXX_THROW_OR_ABORT(__concurrence_lock_error()); }
inline void
__throw_concurrence_unlock_error()
{ _GLIBCXX_THROW_OR_ABORT(__concurrence_unlock_error()); }
#ifdef __GTHREAD_HAS_COND
inline void
__throw_concurrence_broadcast_error()
{ _GLIBCXX_THROW_OR_ABORT(__concurrence_broadcast_error()); }
inline void
__throw_concurrence_wait_error()
{ _GLIBCXX_THROW_OR_ABORT(__concurrence_wait_error()); }
#endif
class __mutex
{
private:
#if __GTHREADS && defined __GTHREAD_MUTEX_INIT
__gthread_mutex_t _M_mutex = __GTHREAD_MUTEX_INIT;
#else
__gthread_mutex_t _M_mutex;
#endif
__mutex(const __mutex&);
__mutex& operator=(const __mutex&);
public:
__mutex()
{
#if __GTHREADS && ! defined __GTHREAD_MUTEX_INIT
if (__gthread_active_p())
__GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex);
#endif
}
#if __GTHREADS && ! defined __GTHREAD_MUTEX_INIT
~__mutex()
{
if (__gthread_active_p())
__gthread_mutex_destroy(&_M_mutex);
}
#endif
void lock()
{
#if __GTHREADS
if (__gthread_active_p())
{
if (__gthread_mutex_lock(&_M_mutex) != 0)
__throw_concurrence_lock_error();
}
#endif
}
void unlock()
{
#if __GTHREADS
if (__gthread_active_p())
{
if (__gthread_mutex_unlock(&_M_mutex) != 0)
__throw_concurrence_unlock_error();
}
#endif
}
__gthread_mutex_t* gthread_mutex(void)
{ return &_M_mutex; }
};
class __recursive_mutex
{
private:
#if __GTHREADS && defined __GTHREAD_RECURSIVE_MUTEX_INIT
__gthread_recursive_mutex_t _M_mutex = __GTHREAD_RECURSIVE_MUTEX_INIT;
#else
__gthread_recursive_mutex_t _M_mutex;
#endif
__recursive_mutex(const __recursive_mutex&);
__recursive_mutex& operator=(const __recursive_mutex&);
public:
__recursive_mutex()
{
#if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT
if (__gthread_active_p())
__GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex);
#endif
}
#if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT
~__recursive_mutex()
{
if (__gthread_active_p())
__gthread_recursive_mutex_destroy(&_M_mutex);
}
#endif
void lock()
{
#if __GTHREADS
if (__gthread_active_p())
{
if (__gthread_recursive_mutex_lock(&_M_mutex) != 0)
__throw_concurrence_lock_error();
}
#endif
}
void unlock()
{
#if __GTHREADS
if (__gthread_active_p())
{
if (__gthread_recursive_mutex_unlock(&_M_mutex) != 0)
__throw_concurrence_unlock_error();
}
#endif
}
__gthread_recursive_mutex_t* gthread_recursive_mutex(void)
{ return &_M_mutex; }
};
/// Scoped lock idiom.
// Acquire the mutex here with a constructor call, then release with
// the destructor call in accordance with RAII style.
class __scoped_lock
{
public:
typedef __mutex __mutex_type;
private:
__mutex_type& _M_device;
__scoped_lock(const __scoped_lock&);
__scoped_lock& operator=(const __scoped_lock&);
public:
explicit __scoped_lock(__mutex_type& __name) : _M_device(__name)
{ _M_device.lock(); }
~__scoped_lock() throw()
{ _M_device.unlock(); }
};
#ifdef __GTHREAD_HAS_COND
class __cond
{
private:
#if __GTHREADS && defined __GTHREAD_COND_INIT
__gthread_cond_t _M_cond = __GTHREAD_COND_INIT;
#else
__gthread_cond_t _M_cond;
#endif
__cond(const __cond&);
__cond& operator=(const __cond&);
public:
__cond()
{
#if __GTHREADS && ! defined __GTHREAD_COND_INIT
if (__gthread_active_p())
__GTHREAD_COND_INIT_FUNCTION(&_M_cond);
#endif
}
#if __GTHREADS && ! defined __GTHREAD_COND_INIT
~__cond()
{
if (__gthread_active_p())
__gthread_cond_destroy(&_M_cond);
}
#endif
void broadcast()
{
#if __GTHREADS
if (__gthread_active_p())
{
if (__gthread_cond_broadcast(&_M_cond) != 0)
__throw_concurrence_broadcast_error();
}
#endif
}
void wait(__mutex *mutex)
{
#if __GTHREADS
{
if (__gthread_cond_wait(&_M_cond, mutex->gthread_mutex()) != 0)
__throw_concurrence_wait_error();
}
#endif
}
void wait_recursive(__recursive_mutex *mutex)
{
#if __GTHREADS
{
if (__gthread_cond_wait_recursive(&_M_cond,
mutex->gthread_recursive_mutex())
!= 0)
__throw_concurrence_wait_error();
}
#endif
}
};
#endif
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
#endif