1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef _LIBCPP___EXCEPTION_NESTED_EXCEPTION_H
10#define _LIBCPP___EXCEPTION_NESTED_EXCEPTION_H
11
12#include <__config>
13#include <__exception/exception_ptr.h>
14#include <__memory/addressof.h>
15#include <__type_traits/decay.h>
16#include <__type_traits/enable_if.h>
17#include <__type_traits/integral_constant.h>
18#include <__type_traits/is_base_of.h>
19#include <__type_traits/is_class.h>
20#include <__type_traits/is_constructible.h>
21#include <__type_traits/is_convertible.h>
22#include <__type_traits/is_final.h>
23#include <__type_traits/is_polymorphic.h>
24#include <__utility/forward.h>
25
26#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
27# pragma GCC system_header
28#endif
29
30_LIBCPP_BEGIN_UNVERSIONED_NAMESPACE_STD
31
32class _LIBCPP_EXPORTED_FROM_ABI nested_exception {
33 exception_ptr __ptr_;
34
35public:
36 nested_exception() _NOEXCEPT;
37 _LIBCPP_HIDE_FROM_ABI nested_exception(const nested_exception&) _NOEXCEPT = default;
38 _LIBCPP_HIDE_FROM_ABI nested_exception& operator=(const nested_exception&) _NOEXCEPT = default;
39 virtual ~nested_exception() _NOEXCEPT;
40
41 // access functions
42 [[__noreturn__]] void rethrow_nested() const;
43 _LIBCPP_HIDE_FROM_ABI exception_ptr nested_ptr() const _NOEXCEPT { return __ptr_; }
44};
45
46template <class _Tp>
47struct __nested : public _Tp, public nested_exception {
48 _LIBCPP_HIDE_FROM_ABI explicit __nested(const _Tp& __t) : _Tp(__t) {}
49};
50
51#if _LIBCPP_HAS_EXCEPTIONS
52template <class _Tp, class _Up, bool>
53struct __throw_with_nested;
54
55template <class _Tp, class _Up>
56struct __throw_with_nested<_Tp, _Up, true> {
57 [[__noreturn__]] static inline _LIBCPP_HIDE_FROM_ABI void __do_throw(_Tp&& __t) {
58 throw __nested<_Up>(std::forward<_Tp>(__t));
59 }
60};
61
62template <class _Tp, class _Up>
63struct __throw_with_nested<_Tp, _Up, false> {
64 [[__noreturn__]] static inline _LIBCPP_HIDE_FROM_ABI void __do_throw(_Tp&& __t) { throw std::forward<_Tp>(__t); }
65};
66#endif
67
68template <class _Tp>
69[[__noreturn__]] _LIBCPP_HIDE_FROM_ABI void throw_with_nested(_Tp&& __t) {
70#if _LIBCPP_HAS_EXCEPTIONS
71 using _Up = __decay_t<_Tp>;
72 static_assert(is_copy_constructible<_Up>::value, "type thrown must be CopyConstructible");
73 __throw_with_nested<_Tp,
74 _Up,
75 is_class<_Up>::value && !is_base_of<nested_exception, _Up>::value &&
76 !__libcpp_is_final<_Up>::value>::__do_throw(std::forward<_Tp>(__t));
77#else
78 ((void)__t);
79 // FIXME: Make this abort
80#endif
81}
82
83template <class _From, class _To>
84struct __can_dynamic_cast
85 : _BoolConstant< is_polymorphic<_From>::value &&
86 (!is_base_of<_To, _From>::value || is_convertible<const _From*, const _To*>::value)> {};
87
88template <class _Ep, __enable_if_t< __can_dynamic_cast<_Ep, nested_exception>::value, int> = 0>
89inline _LIBCPP_HIDE_FROM_ABI void rethrow_if_nested(const _Ep& __e) {
90 const nested_exception* __nep = dynamic_cast<const nested_exception*>(std::addressof(__e));
91 if (__nep)
92 __nep->rethrow_nested();
93}
94
95template <class _Ep, __enable_if_t<!__can_dynamic_cast<_Ep, nested_exception>::value, int> = 0>
96inline _LIBCPP_HIDE_FROM_ABI void rethrow_if_nested(const _Ep&) {}
97
98_LIBCPP_END_UNVERSIONED_NAMESPACE_STD
99
100#endif // _LIBCPP___EXCEPTION_NESTED_EXCEPTION_H
101