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

// Copyright (C) 2009, 2010, 2011 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 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 <bits/c++0x_warning.h>

#else

#include <bits/c++config.h>

#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&) = default;

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

    virtual ~nested_exception() noexcept;

    void

    rethrow_nested() const __attribute__ ((__noreturn__))

    { rethrow_exception(_M_ptr); }

    exception_ptr

    nested_ptr() const

    { return _M_ptr; }

  };

  template<typename _Except>

    struct _Nested_exception : public _Except, public nested_exception

    {

      explicit _Nested_exception(_Except&& __ex)

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

      { }

    };

  template<typename _Ex>

    struct __get_nested_helper

    {

      static const nested_exception*

      _S_get(const _Ex& __ex)

      { return dynamic_cast<const nested_exception*>(&__ex); }

    };

  template<typename _Ex>

    struct __get_nested_helper<_Ex*>

    {

      static const nested_exception*

      _S_get(const _Ex* __ex)

      { return dynamic_cast<const nested_exception*>(__ex); }

    };

  template<typename _Ex>

    inline const nested_exception*

    __get_nested_exception(const _Ex& __ex)

    { return __get_nested_helper<_Ex>::_S_get(__ex); }

  template<typename _Ex>

    void

    __throw_with_nested(_Ex&&, const nested_exception* = 0)

    __attribute__ ((__noreturn__));

  template<typename _Ex>

    void

    __throw_with_nested(_Ex&&, ...) __attribute__ ((__noreturn__));

  // This function should never be called, but is needed to avoid a warning

  // about ambiguous base classes when instantiating throw_with_nested<_Ex>()

  // with a type that has an accessible nested_exception base.

  template<typename _Ex>

    inline void

    __throw_with_nested(_Ex&& __ex, const nested_exception*)

    { throw __ex; }

  template<typename _Ex>

    inline void

    __throw_with_nested(_Ex&& __ex, ...)

    { throw _Nested_exception<_Ex>(static_cast<_Ex&&>(__ex)); }

  template<typename _Ex>

    void

    throw_with_nested(_Ex __ex) __attribute__ ((__noreturn__));

  /// If @p __ex is derived from nested_exception, @p __ex. 

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

  template<typename _Ex>

    inline void

    throw_with_nested(_Ex __ex)

    {

      if (__get_nested_exception(__ex))

        throw __ex;

      __throw_with_nested(static_cast<_Ex&&>(__ex), &__ex);

    }

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

  template<typename _Ex>

    inline void

    rethrow_if_nested(const _Ex& __ex)

    {

      if (const nested_exception* __nested = __get_nested_exception(__ex))

        __nested->rethrow_nested();

    }

  /// Overload, See N2619

  inline void

  rethrow_if_nested(const nested_exception& __ex)

  { __ex.rethrow_nested(); }

  // @} group exceptions

} // namespace std

} // extern "C++"

#endif // C++11

#pragma GCC visibility pop

#endif // _GLIBCXX_NESTED_EXCEPTION_H