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1// -*- C++ -*-
2//===-------------------------- exception ---------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is dual licensed under the MIT and the University of Illinois Open
7// Source Licenses. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP_EXCEPTION
12#define _LIBCPP_EXCEPTION
13
14/*
15    exception synopsis
16
17namespace std
18{
19
20class exception
21{
22public:
23    exception() noexcept;
24    exception(const exception&) noexcept;
25    exception& operator=(const exception&) noexcept;
26    virtual ~exception() noexcept;
27    virtual const char* what() const noexcept;
28};
29
30class bad_exception
31    : public exception
32{
33public:
34    bad_exception() noexcept;
35    bad_exception(const bad_exception&) noexcept;
36    bad_exception& operator=(const bad_exception&) noexcept;
37    virtual ~bad_exception() noexcept;
38    virtual const char* what() const noexcept;
39};
40
41typedef void (*unexpected_handler)();
42unexpected_handler set_unexpected(unexpected_handler  f ) noexcept;
43unexpected_handler get_unexpected() noexcept;
44[[noreturn]] void unexpected();
45
46typedef void (*terminate_handler)();
47terminate_handler set_terminate(terminate_handler  f ) noexcept;
48terminate_handler get_terminate() noexcept;
49[[noreturn]] void terminate() noexcept;
50
51bool uncaught_exception()  noexcept;
52int  uncaught_exceptions() noexcept;  // C++17
53
54typedef unspecified exception_ptr;
55
56exception_ptr current_exception() noexcept;
57void rethrow_exception [[noreturn]] (exception_ptr p);
58template<class E> exception_ptr make_exception_ptr(E e) noexcept;
59
60class nested_exception
61{
62public:
63    nested_exception() noexcept;
64    nested_exception(const nested_exception&) noexcept = default;
65    nested_exception& operator=(const nested_exception&) noexcept = default;
66    virtual ~nested_exception() = default;
67
68    // access functions
69    [[noreturn]] void rethrow_nested() const;
70    exception_ptr nested_ptr() const noexcept;
71};
72
73template <class T> [[noreturn]] void throw_with_nested(T&& t);
74template <class E> void rethrow_if_nested(const E& e);
75
76}  // std
77
78*/
79
80#include <__config>
81#include <cstddef>
82#include <cstdlib>
83#include <type_traits>
84
85#if defined(_LIBCPP_ABI_MICROSOFT)
86#include <vcruntime_exception.h>
87#endif
88
89#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
90#pragma GCC system_header
91#endif
92
93namespace std  // purposefully not using versioning namespace
94{
95
96#if !defined(_LIBCPP_ABI_MICROSOFT)
97class _LIBCPP_EXCEPTION_ABI exception
98{
99public:
100    _LIBCPP_INLINE_VISIBILITY exception() _NOEXCEPT {}
101    virtual ~exception() _NOEXCEPT;
102    virtual const char* what() const _NOEXCEPT;
103};
104
105class _LIBCPP_EXCEPTION_ABI bad_exception
106    : public exception
107{
108public:
109    _LIBCPP_INLINE_VISIBILITY bad_exception() _NOEXCEPT {}
110    virtual ~bad_exception() _NOEXCEPT;
111    virtual const char* what() const _NOEXCEPT;
112};
113#endif // !_LIBCPP_ABI_MICROSOFT
114
115#if _LIBCPP_STD_VER <= 14 \
116    || defined(_LIBCPP_ENABLE_CXX17_REMOVED_UNEXPECTED_FUNCTIONS) \
117    || defined(_LIBCPP_BUILDING_LIBRARY)
118typedef void (*unexpected_handler)();
119_LIBCPP_FUNC_VIS unexpected_handler set_unexpected(unexpected_handler) _NOEXCEPT;
120_LIBCPP_FUNC_VIS unexpected_handler get_unexpected() _NOEXCEPT;
121_LIBCPP_NORETURN _LIBCPP_FUNC_VIS void unexpected();
122#endif
123
124typedef void (*terminate_handler)();
125_LIBCPP_FUNC_VIS terminate_handler set_terminate(terminate_handler) _NOEXCEPT;
126_LIBCPP_FUNC_VIS terminate_handler get_terminate() _NOEXCEPT;
127_LIBCPP_NORETURN _LIBCPP_FUNC_VIS void terminate() _NOEXCEPT;
128
129_LIBCPP_FUNC_VIS bool uncaught_exception() _NOEXCEPT;
130_LIBCPP_FUNC_VIS int uncaught_exceptions() _NOEXCEPT;
131
132class _LIBCPP_TYPE_VIS exception_ptr;
133
134_LIBCPP_FUNC_VIS exception_ptr current_exception() _NOEXCEPT;
135_LIBCPP_NORETURN _LIBCPP_FUNC_VIS void rethrow_exception(exception_ptr);
136
137class _LIBCPP_TYPE_VIS exception_ptr
138{
139    void* __ptr_;
140public:
141    _LIBCPP_INLINE_VISIBILITY exception_ptr() _NOEXCEPT : __ptr_() {}
142    _LIBCPP_INLINE_VISIBILITY exception_ptr(nullptr_t) _NOEXCEPT : __ptr_() {}
143    exception_ptr(const exception_ptr&) _NOEXCEPT;
144    exception_ptr& operator=(const exception_ptr&) _NOEXCEPT;
145    ~exception_ptr() _NOEXCEPT;
146
147    _LIBCPP_INLINE_VISIBILITY
148    _LIBCPP_EXPLICIT
149        operator bool() const _NOEXCEPT {return __ptr_ != nullptr;}
150
151    friend _LIBCPP_INLINE_VISIBILITY
152    bool operator==(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT
153        {return __x.__ptr_ == __y.__ptr_;}
154    friend _LIBCPP_INLINE_VISIBILITY
155    bool operator!=(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT
156        {return !(__x == __y);}
157
158    friend _LIBCPP_FUNC_VIS exception_ptr current_exception() _NOEXCEPT;
159    friend _LIBCPP_FUNC_VIS void rethrow_exception(exception_ptr);
160};
161
162template<class _Ep>
163exception_ptr
164make_exception_ptr(_Ep __e) _NOEXCEPT
165{
166#ifndef _LIBCPP_NO_EXCEPTIONS
167    try
168    {
169        throw __e;
170    }
171    catch (...)
172    {
173        return current_exception();
174    }
175#else
176    ((void)__e);
177    _VSTD::abort();
178#endif
179}
180
181// nested_exception
182
183class _LIBCPP_EXCEPTION_ABI nested_exception
184{
185    exception_ptr __ptr_;
186public:
187    nested_exception() _NOEXCEPT;
188//     nested_exception(const nested_exception&) noexcept = default;
189//     nested_exception& operator=(const nested_exception&) noexcept = default;
190    virtual ~nested_exception() _NOEXCEPT;
191
192    // access functions
193    _LIBCPP_NORETURN void rethrow_nested() const;
194    _LIBCPP_INLINE_VISIBILITY exception_ptr nested_ptr() const _NOEXCEPT {return __ptr_;}
195};
196
197template <class _Tp>
198struct __nested
199    : public _Tp,
200      public nested_exception
201{
202    _LIBCPP_INLINE_VISIBILITY explicit __nested(const _Tp& __t) : _Tp(__t) {}
203};
204
205template <class _Tp>
206_LIBCPP_NORETURN
207void
208#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
209throw_with_nested(_Tp&& __t, typename enable_if<
210                  is_class<typename remove_reference<_Tp>::type>::value &&
211                  !is_base_of<nested_exception, typename remove_reference<_Tp>::type>::value
212                  && !__libcpp_is_final<typename remove_reference<_Tp>::type>::value
213                                    >::type* = 0)
214#else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
215throw_with_nested (_Tp& __t, typename enable_if<
216                  is_class<_Tp>::value && !is_base_of<nested_exception, _Tp>::value
217                                    >::type* = 0)
218#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
219{
220#ifndef _LIBCPP_NO_EXCEPTIONS
221    throw __nested<typename remove_reference<_Tp>::type>(_VSTD::forward<_Tp>(__t));
222#else
223    ((void)__t);
224    // FIXME: Make this abort.
225#endif
226}
227
228template <class _Tp>
229_LIBCPP_NORETURN
230void
231#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
232throw_with_nested(_Tp&& __t, typename enable_if<
233                  !is_class<typename remove_reference<_Tp>::type>::value ||
234                  is_base_of<nested_exception, typename remove_reference<_Tp>::type>::value
235                  || __libcpp_is_final<typename remove_reference<_Tp>::type>::value
236                                    >::type* = 0)
237#else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
238throw_with_nested (_Tp& __t, typename enable_if<
239                  !is_class<_Tp>::value || is_base_of<nested_exception, _Tp>::value
240                                    >::type* = 0)
241#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
242{
243#ifndef _LIBCPP_NO_EXCEPTIONS
244    throw _VSTD::forward<_Tp>(__t);
245#else
246    ((void)__t);
247    // FIXME: Make this abort
248#endif
249}
250
251template <class _From, class _To>
252struct __can_dynamic_cast : public _LIBCPP_BOOL_CONSTANT(
253              is_polymorphic<_From>::value &&
254                 (!is_base_of<_To, _From>::value ||
255                   is_convertible<const _From*, const _To*>::value)) {};
256
257template <class _Ep>
258inline _LIBCPP_INLINE_VISIBILITY
259void
260rethrow_if_nested(const _Ep& __e,
261                  typename enable_if< __can_dynamic_cast<_Ep, nested_exception>::value>::type* = 0)
262{
263    const nested_exception* __nep = dynamic_cast<const nested_exception*>(_VSTD::addressof(__e));
264    if (__nep)
265        __nep->rethrow_nested();
266}
267
268template <class _Ep>
269inline _LIBCPP_INLINE_VISIBILITY
270void
271rethrow_if_nested(const _Ep&,
272                  typename enable_if<!__can_dynamic_cast<_Ep, nested_exception>::value>::type* = 0)
273{
274}
275
276}  // std
277
278#endif  // _LIBCPP_EXCEPTION
279