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// Nested Exception support header (nested_exception class) for -*- C++ -*-

// Copyright (C) 2009-2015 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

// .

/** @file bits/nested_exception.h

 *  This is an internal header file, included by other library headers.

 *  Do not attempt to use it directly. @headername{exception}

 */

#ifndef _GLIBCXX_NESTED_EXCEPTION_H

#define _GLIBCXX_NESTED_EXCEPTION_H 1

#pragma GCC visibility push(default)

#if __cplusplus < 201103L

# include 

#else

#include 

#if ATOMIC_INT_LOCK_FREE < 2

#  error This platform does not support exception propagation.

#endif

extern "C++" {

namespace std

{

  /**

   * @addtogroup exceptions

   * @{

   */

  /// Exception class with exception_ptr data member.

  class nested_exception

  {

    exception_ptr _M_ptr;

  public:

    nested_exception() noexcept : _M_ptr(current_exception()) { }

    nested_exception(const nested_exception&) noexcept = default;

    nested_exception& operator=(const nested_exception&) noexcept = default;

    virtual ~nested_exception() noexcept;

    [[noreturn]]

    void

    rethrow_nested() const

    {

      if (_M_ptr)

	rethrow_exception(_M_ptr);

      std::terminate();

    }

    exception_ptr

    nested_ptr() const noexcept

    { return _M_ptr; }

  };

  template

    struct _Nested_exception : public _Except, public nested_exception

    {

      explicit _Nested_exception(const _Except& __ex)

      : _Except(__ex)

      { }

      explicit _Nested_exception(_Except&& __ex)

      : _Except(static_cast<_Except&&>(__ex))

      { }

    };

  template

	   bool __with_nested = !__is_base_of(nested_exception, _Tp)>

    struct _Throw_with_nested_impl

    {

      template

	static void _S_throw(_Up&& __t)

	{ throw _Nested_exception<_Tp>{static_cast<_Up&&>(__t)}; }

    };

  template

    struct _Throw_with_nested_impl<_Tp, false>

    {

      template

	static void _S_throw(_Up&& __t)

	{ throw static_cast<_Up&&>(__t); }

    };

  template

    struct _Throw_with_nested_helper : _Throw_with_nested_impl<_Tp>

    { };

  template

    struct _Throw_with_nested_helper<_Tp, false>

    : _Throw_with_nested_impl<_Tp, false>

    { };

  template

    struct _Throw_with_nested_helper<_Tp&, false>

    : _Throw_with_nested_helper<_Tp>

    { };

  template

    struct _Throw_with_nested_helper<_Tp&&, false>

    : _Throw_with_nested_helper<_Tp>

    { };

  /// If @p __t is derived from nested_exception, throws @p __t.

  /// Else, throws an implementation-defined object derived from both.

  template

    [[noreturn]]

    inline void

    throw_with_nested(_Tp&& __t)

    {

      _Throw_with_nested_helper<_Tp>::_S_throw(static_cast<_Tp&&>(__t));

    }

  template

    struct _Rethrow_if_nested_impl

    {

      static void _S_rethrow(const _Tp& __t)

      {

	if (auto __tp = dynamic_cast(&__t))

	  __tp->rethrow_nested();

      }

    };

  template

    struct _Rethrow_if_nested_impl<_Tp, false>

    {

      static void _S_rethrow(const _Tp&) { }

    };

  /// If @p __ex is derived from nested_exception, @p __ex.rethrow_nested().

  template

    inline void

    rethrow_if_nested(const _Ex& __ex)

    {

      _Rethrow_if_nested_impl<_Ex>::_S_rethrow(__ex);

    }

  // @} group exceptions

} // namespace std

} // extern "C++"

#endif // C++11

#pragma GCC visibility pop

#endif // _GLIBCXX_NESTED_EXCEPTION_H