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_HAS_NO_PRAGMA_SYSTEM_HEADER)
86#pragma GCC system_header
87#endif
88
89namespace std  // purposefully not using versioning namespace
90{
91
92class _LIBCPP_EXCEPTION_ABI exception
93{
94public:
95    _LIBCPP_INLINE_VISIBILITY exception() _NOEXCEPT {}
96    virtual ~exception() _NOEXCEPT;
97    virtual const char* what() const _NOEXCEPT;
98};
99
100class _LIBCPP_EXCEPTION_ABI bad_exception
101    : public exception
102{
103public:
104    _LIBCPP_INLINE_VISIBILITY bad_exception() _NOEXCEPT {}
105    virtual ~bad_exception() _NOEXCEPT;
106    virtual const char* what() const _NOEXCEPT;
107};
108
109typedef void (*unexpected_handler)();
110_LIBCPP_FUNC_VIS unexpected_handler set_unexpected(unexpected_handler) _NOEXCEPT;
111_LIBCPP_FUNC_VIS unexpected_handler get_unexpected() _NOEXCEPT;
112_LIBCPP_NORETURN _LIBCPP_FUNC_VIS void unexpected();
113
114typedef void (*terminate_handler)();
115_LIBCPP_FUNC_VIS terminate_handler set_terminate(terminate_handler) _NOEXCEPT;
116_LIBCPP_FUNC_VIS terminate_handler get_terminate() _NOEXCEPT;
117_LIBCPP_NORETURN _LIBCPP_FUNC_VIS void terminate() _NOEXCEPT;
118
119_LIBCPP_FUNC_VIS bool uncaught_exception() _NOEXCEPT;
120_LIBCPP_FUNC_VIS int uncaught_exceptions() _NOEXCEPT;
121
122class _LIBCPP_TYPE_VIS exception_ptr;
123
124_LIBCPP_FUNC_VIS exception_ptr current_exception() _NOEXCEPT;
125_LIBCPP_NORETURN _LIBCPP_FUNC_VIS void rethrow_exception(exception_ptr);
126
127class _LIBCPP_TYPE_VIS exception_ptr
128{
129    void* __ptr_;
130public:
131    _LIBCPP_INLINE_VISIBILITY exception_ptr() _NOEXCEPT : __ptr_() {}
132    _LIBCPP_INLINE_VISIBILITY exception_ptr(nullptr_t) _NOEXCEPT : __ptr_() {}
133    exception_ptr(const exception_ptr&) _NOEXCEPT;
134    exception_ptr& operator=(const exception_ptr&) _NOEXCEPT;
135    ~exception_ptr() _NOEXCEPT;
136
137    _LIBCPP_INLINE_VISIBILITY
138    _LIBCPP_EXPLICIT
139        operator bool() const _NOEXCEPT {return __ptr_ != nullptr;}
140
141    friend _LIBCPP_INLINE_VISIBILITY
142    bool operator==(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT
143        {return __x.__ptr_ == __y.__ptr_;}
144    friend _LIBCPP_INLINE_VISIBILITY
145    bool operator!=(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT
146        {return !(__x == __y);}
147
148    friend _LIBCPP_FUNC_VIS exception_ptr current_exception() _NOEXCEPT;
149    friend _LIBCPP_FUNC_VIS void rethrow_exception(exception_ptr);
150};
151
152template<class _Ep>
153exception_ptr
154make_exception_ptr(_Ep __e) _NOEXCEPT
155{
156#ifndef _LIBCPP_NO_EXCEPTIONS
157    try
158    {
159        throw __e;
160    }
161    catch (...)
162    {
163        return current_exception();
164    }
165#else
166    ((void)__e);
167    _VSTD::abort();
168#endif
169}
170
171// nested_exception
172
173class _LIBCPP_EXCEPTION_ABI nested_exception
174{
175    exception_ptr __ptr_;
176public:
177    nested_exception() _NOEXCEPT;
178//     nested_exception(const nested_exception&) noexcept = default;
179//     nested_exception& operator=(const nested_exception&) noexcept = default;
180    virtual ~nested_exception() _NOEXCEPT;
181
182    // access functions
183    _LIBCPP_NORETURN void rethrow_nested() const;
184    _LIBCPP_INLINE_VISIBILITY exception_ptr nested_ptr() const _NOEXCEPT {return __ptr_;}
185};
186
187template <class _Tp>
188struct __nested
189    : public _Tp,
190      public nested_exception
191{
192    _LIBCPP_INLINE_VISIBILITY explicit __nested(const _Tp& __t) : _Tp(__t) {}
193};
194
195template <class _Tp>
196_LIBCPP_NORETURN
197void
198#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
199throw_with_nested(_Tp&& __t, typename enable_if<
200                  is_class<typename remove_reference<_Tp>::type>::value &&
201                  !is_base_of<nested_exception, typename remove_reference<_Tp>::type>::value
202                  && !__libcpp_is_final<typename remove_reference<_Tp>::type>::value
203                                    >::type* = 0)
204#else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
205throw_with_nested (_Tp& __t, typename enable_if<
206                  is_class<_Tp>::value && !is_base_of<nested_exception, _Tp>::value
207                                    >::type* = 0)
208#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
209{
210#ifndef _LIBCPP_NO_EXCEPTIONS
211    throw __nested<typename remove_reference<_Tp>::type>(_VSTD::forward<_Tp>(__t));
212#else
213    ((void)__t);
214    // FIXME: Make this abort.
215#endif
216}
217
218template <class _Tp>
219_LIBCPP_NORETURN
220void
221#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
222throw_with_nested(_Tp&& __t, typename enable_if<
223                  !is_class<typename remove_reference<_Tp>::type>::value ||
224                  is_base_of<nested_exception, typename remove_reference<_Tp>::type>::value
225                  || __libcpp_is_final<typename remove_reference<_Tp>::type>::value
226                                    >::type* = 0)
227#else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
228throw_with_nested (_Tp& __t, typename enable_if<
229                  !is_class<_Tp>::value || is_base_of<nested_exception, _Tp>::value
230                                    >::type* = 0)
231#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
232{
233#ifndef _LIBCPP_NO_EXCEPTIONS
234    throw _VSTD::forward<_Tp>(__t);
235#else
236    ((void)__t);
237    // FIXME: Make this abort
238#endif
239}
240
241template <class _Ep>
242inline _LIBCPP_INLINE_VISIBILITY
243void
244rethrow_if_nested(const _Ep& __e, typename enable_if<
245                                   is_polymorphic<_Ep>::value
246                                                   >::type* = 0)
247{
248    const nested_exception* __nep = dynamic_cast<const nested_exception*>(_VSTD::addressof(__e));
249    if (__nep)
250        __nep->rethrow_nested();
251}
252
253template <class _Ep>
254inline _LIBCPP_INLINE_VISIBILITY
255void
256rethrow_if_nested(const _Ep&, typename enable_if<
257                                   !is_polymorphic<_Ep>::value
258                                                   >::type* = 0)
259{
260}
261
262}  // std
263
264#endif  // _LIBCPP_EXCEPTION
265