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    _VSTD::abort();
167#endif
168}
169
170// nested_exception
171
172class _LIBCPP_EXCEPTION_ABI nested_exception
173{
174    exception_ptr __ptr_;
175public:
176    nested_exception() _NOEXCEPT;
177//     nested_exception(const nested_exception&) noexcept = default;
178//     nested_exception& operator=(const nested_exception&) noexcept = default;
179    virtual ~nested_exception() _NOEXCEPT;
180
181    // access functions
182    _LIBCPP_NORETURN void rethrow_nested() const;
183    _LIBCPP_INLINE_VISIBILITY exception_ptr nested_ptr() const _NOEXCEPT {return __ptr_;}
184};
185
186template <class _Tp>
187struct __nested
188    : public _Tp,
189      public nested_exception
190{
191    _LIBCPP_INLINE_VISIBILITY explicit __nested(const _Tp& __t) : _Tp(__t) {}
192};
193
194template <class _Tp>
195_LIBCPP_NORETURN
196void
197#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
198throw_with_nested(_Tp&& __t, typename enable_if<
199                  is_class<typename remove_reference<_Tp>::type>::value &&
200                  !is_base_of<nested_exception, typename remove_reference<_Tp>::type>::value
201                  && !__libcpp_is_final<typename remove_reference<_Tp>::type>::value
202                                    >::type* = 0)
203#else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
204throw_with_nested (_Tp& __t, typename enable_if<
205                  is_class<_Tp>::value && !is_base_of<nested_exception, _Tp>::value
206                                    >::type* = 0)
207#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
208{
209#ifndef _LIBCPP_NO_EXCEPTIONS
210    throw __nested<typename remove_reference<_Tp>::type>(_VSTD::forward<_Tp>(__t));
211#endif
212}
213
214template <class _Tp>
215_LIBCPP_NORETURN
216void
217#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
218throw_with_nested(_Tp&& __t, typename enable_if<
219                  !is_class<typename remove_reference<_Tp>::type>::value ||
220                  is_base_of<nested_exception, typename remove_reference<_Tp>::type>::value
221                  || __libcpp_is_final<typename remove_reference<_Tp>::type>::value
222                                    >::type* = 0)
223#else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
224throw_with_nested (_Tp& __t, typename enable_if<
225                  !is_class<_Tp>::value || is_base_of<nested_exception, _Tp>::value
226                                    >::type* = 0)
227#endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
228{
229#ifndef _LIBCPP_NO_EXCEPTIONS
230    throw _VSTD::forward<_Tp>(__t);
231#endif
232}
233
234template <class _Ep>
235inline _LIBCPP_INLINE_VISIBILITY
236void
237rethrow_if_nested(const _Ep& __e, typename enable_if<
238                                   is_polymorphic<_Ep>::value
239                                                   >::type* = 0)
240{
241    const nested_exception* __nep = dynamic_cast<const nested_exception*>(_VSTD::addressof(__e));
242    if (__nep)
243        __nep->rethrow_nested();
244}
245
246template <class _Ep>
247inline _LIBCPP_INLINE_VISIBILITY
248void
249rethrow_if_nested(const _Ep&, typename enable_if<
250                                   !is_polymorphic<_Ep>::value
251                                                   >::type* = 0)
252{
253}
254
255}  // std
256
257#endif  // _LIBCPP_EXCEPTION
258