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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
// <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&) 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<typename _Except>
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<typename _Tp,
bool __with_nested = !__is_base_of(nested_exception, _Tp)>
struct _Throw_with_nested_impl
{
template<typename _Up>
static void _S_throw(_Up&& __t)
{ throw _Nested_exception<_Tp>{static_cast<_Up&&>(__t)}; }
};
template<typename _Tp>
struct _Throw_with_nested_impl<_Tp, false>
{
template<typename _Up>
static void _S_throw(_Up&& __t)
{ throw static_cast<_Up&&>(__t); }
};
template<typename _Tp, bool = __is_class(_Tp) && !__is_final(_Tp)>
struct _Throw_with_nested_helper : _Throw_with_nested_impl<_Tp>
{ };
template<typename _Tp>
struct _Throw_with_nested_helper<_Tp, false>
: _Throw_with_nested_impl<_Tp, false>
{ };
template<typename _Tp>
struct _Throw_with_nested_helper<_Tp&, false>
: _Throw_with_nested_helper<_Tp>
{ };
template<typename _Tp>
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<typename _Tp>
[[noreturn]]
inline void
throw_with_nested(_Tp&& __t)
{
_Throw_with_nested_helper<_Tp>::_S_throw(static_cast<_Tp&&>(__t));
}
template<typename _Tp, bool = __is_polymorphic(_Tp)>
struct _Rethrow_if_nested_impl
{
static void _S_rethrow(const _Tp& __t)
{
if (auto __tp = dynamic_cast<const nested_exception*>(&__t))
__tp->rethrow_nested();
}
};
template<typename _Tp>
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<typename _Ex>
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
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