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// Support for concurrent programing -*- C++ -*-

// Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010

// 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()

  {

#if __EXCEPTIONS

    throw __concurrence_lock_error();

#else

    __builtin_abort();

#endif

  }

  inline void

  __throw_concurrence_unlock_error()

  {

#if __EXCEPTIONS

    throw __concurrence_unlock_error();

#else

    __builtin_abort();

#endif

  }

#ifdef __GTHREAD_HAS_COND

  inline void

  __throw_concurrence_broadcast_error()

  {

#if __EXCEPTIONS

    throw __concurrence_broadcast_error();

#else

    __builtin_abort();

#endif

  }

  inline void

  __throw_concurrence_wait_error()

  {

#if __EXCEPTIONS

    throw __concurrence_wait_error();

#else

    __builtin_abort();

#endif

  }

#endif

  class __mutex

  {

  private:

    __gthread_mutex_t _M_mutex;

    __mutex(const __mutex&);

    __mutex& operator=(const __mutex&);

  public:

    __mutex()

    {

#if __GTHREADS

      if (__gthread_active_p())

        {

#if defined __GTHREAD_MUTEX_INIT

          __gthread_mutex_t __tmp = __GTHREAD_MUTEX_INIT;

          _M_mutex = __tmp;

#else

          __GTHREAD_MUTEX_INIT_FUNCTION(&_M_mutex);

#endif

        }

#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:

    __gthread_recursive_mutex_t _M_mutex;

    __recursive_mutex(const __recursive_mutex&);

    __recursive_mutex& operator=(const __recursive_mutex&);

  public:

    __recursive_mutex()

    {

#if __GTHREADS

      if (__gthread_active_p())

        {

#if defined __GTHREAD_RECURSIVE_MUTEX_INIT

          __gthread_recursive_mutex_t __tmp = __GTHREAD_RECURSIVE_MUTEX_INIT;

          _M_mutex = __tmp;

#else

          __GTHREAD_RECURSIVE_MUTEX_INIT_FUNCTION(&_M_mutex);

#endif

        }

#endif 

    }

#if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT

    ~__recursive_mutex()

    {

      if (__gthread_active_p())

        _S_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; }

#if __GTHREADS && ! defined __GTHREAD_RECURSIVE_MUTEX_INIT

    // FIXME: gthreads doesn't define __gthread_recursive_mutex_destroy

    // so we need to obtain a __gthread_mutex_t to destroy

  private:

    template<typename _Mx, typename _Rm>

      static void

      _S_destroy_win32(_Mx* __mx, _Rm const* __rmx)

      {

        __mx->counter = __rmx->counter;

        __mx->sema = __rmx->sema;

        __gthread_mutex_destroy(__mx);

      }

    // matches a gthr-win32.h recursive mutex

    template<typename _Rm>

      static typename __enable_if<sizeof(&_Rm::sema), void>::__type

      _S_destroy(_Rm* __mx)

      {

        __gthread_mutex_t __tmp;

        _S_destroy_win32(&__tmp, __mx);

      }

    // matches a recursive mutex with a member 'actual'

    template<typename _Rm>

      static typename __enable_if<sizeof(&_Rm::actual), void>::__type

      _S_destroy(_Rm* __mx)

      { __gthread_mutex_destroy(&__mx->actual); }

    // matches when there's only one mutex type

    template<typename _Rm>

      static typename

      __enable_if<std::__are_same<_Rm, __gthread_mutex_t>::__value,

        void>::__type

      _S_destroy(_Rm* __mx)

      { __gthread_mutex_destroy(__mx); }

#endif

  };

  /// 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:

    __gthread_cond_t _M_cond;

    __cond(const __cond&);

    __cond& operator=(const __cond&);

  public:

    __cond()

    {

#if __GTHREADS

      if (__gthread_active_p())

        {

#if defined __GTHREAD_COND_INIT

          __gthread_cond_t __tmp = __GTHREAD_COND_INIT;

          _M_cond = __tmp;

#else

          __GTHREAD_COND_INIT_FUNCTION(&_M_cond);

#endif

        }

#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