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/is_base_of.h>
17#include <__type_traits/is_class.h>
18#include <__type_traits/is_constructible.h>
19#include <__type_traits/is_convertible.h>
20#include <__type_traits/is_final.h>
21#include <__type_traits/is_polymorphic.h>
22#include <__utility/forward.h>
23#include <cstddef>
24
25#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
26# pragma GCC system_header
27#endif
28
29namespace std { // purposefully not using versioning namespace
30
31class _LIBCPP_EXPORTED_FROM_ABI nested_exception {
32 exception_ptr __ptr_;
33
34public:
35 nested_exception() _NOEXCEPT;
36 _LIBCPP_HIDE_FROM_ABI nested_exception(const nested_exception&) _NOEXCEPT = default;
37 _LIBCPP_HIDE_FROM_ABI nested_exception& operator=(const nested_exception&) _NOEXCEPT = default;
38 virtual ~nested_exception() _NOEXCEPT;
39
40 // access functions
41 _LIBCPP_NORETURN void rethrow_nested() const;
42 _LIBCPP_HIDE_FROM_ABI exception_ptr nested_ptr() const _NOEXCEPT { return __ptr_; }
43};
44
45template <class _Tp>
46struct __nested : public _Tp, public nested_exception {
47 _LIBCPP_HIDE_FROM_ABI explicit __nested(const _Tp& __t) : _Tp(__t) {}
48};
49
50#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
51template <class _Tp, class _Up, bool>
52struct __throw_with_nested;
53
54template <class _Tp, class _Up>
55struct __throw_with_nested<_Tp, _Up, true> {
56 _LIBCPP_NORETURN static inline _LIBCPP_HIDE_FROM_ABI void __do_throw(_Tp&& __t) {
57 throw __nested<_Up>(std::forward<_Tp>(__t));
58 }
59};
60
61template <class _Tp, class _Up>
62struct __throw_with_nested<_Tp, _Up, false> {
63 _LIBCPP_NORETURN static inline _LIBCPP_HIDE_FROM_ABI void __do_throw(_Tp&& __t) { throw std::forward<_Tp>(__t); }
64};
65#endif
66
67template <class _Tp>
68_LIBCPP_NORETURN _LIBCPP_HIDE_FROM_ABI void throw_with_nested(_Tp&& __t) {
69#ifndef _LIBCPP_HAS_NO_EXCEPTIONS
70 using _Up = __decay_t<_Tp>;
71 static_assert(is_copy_constructible<_Up>::value, "type thrown must be CopyConstructible");
72 __throw_with_nested<_Tp,
73 _Up,
74 is_class<_Up>::value && !is_base_of<nested_exception, _Up>::value &&
75 !__libcpp_is_final<_Up>::value>::__do_throw(std::forward<_Tp>(__t));
76#else
77 ((void)__t);
78 // FIXME: Make this abort
79#endif
80}
81
82template <class _From, class _To>
83struct __can_dynamic_cast
84 : _BoolConstant< is_polymorphic<_From>::value &&
85 (!is_base_of<_To, _From>::value || is_convertible<const _From*, const _To*>::value)> {};
86
87template <class _Ep, __enable_if_t< __can_dynamic_cast<_Ep, nested_exception>::value, int> = 0>
88inline _LIBCPP_HIDE_FROM_ABI void rethrow_if_nested(const _Ep& __e) {
89 const nested_exception* __nep = dynamic_cast<const nested_exception*>(std::addressof(__e));
90 if (__nep)
91 __nep->rethrow_nested();
92}
93
94template <class _Ep, __enable_if_t<!__can_dynamic_cast<_Ep, nested_exception>::value, int> = 0>
95inline _LIBCPP_HIDE_FROM_ABI void rethrow_if_nested(const _Ep&) {}
96
97} // namespace std
98
99#endif // _LIBCPP___EXCEPTION_NESTED_EXCEPTION_H
100