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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 
     17 namespace std
     18 {
     19 
     20 class exception
     21 {
     22 public:
     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 
     30 class bad_exception
     31     : public exception
     32 {
     33 public:
     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 
     41 typedef void (*unexpected_handler)();
     42 unexpected_handler set_unexpected(unexpected_handler  f ) noexcept;
     43 unexpected_handler get_unexpected() noexcept;
     44 [[noreturn]] void unexpected();
     45 
     46 typedef void (*terminate_handler)();
     47 terminate_handler set_terminate(terminate_handler  f ) noexcept;
     48 terminate_handler get_terminate() noexcept;
     49 [[noreturn]] void terminate() noexcept;
     50 
     51 bool uncaught_exception()  noexcept;
     52 int  uncaught_exceptions() noexcept;  // C++17
     53 
     54 typedef unspecified exception_ptr;
     55 
     56 exception_ptr current_exception() noexcept;
     57 void rethrow_exception [[noreturn]] (exception_ptr p);
     58 template<class E> exception_ptr make_exception_ptr(E e) noexcept;
     59 
     60 class nested_exception
     61 {
     62 public:
     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 
     73 template <class T> [[noreturn]] void throw_with_nested(T&& t);
     74 template <class E> void rethrow_if_nested(const E& e);
     75 
     76 }  // std
     77 
     78 */
     79 
     80 #include <__config>
     81 #include <cstddef>
     82 #include <type_traits>
     83 
     84 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
     85 #pragma GCC system_header
     86 #endif
     87 
     88 namespace std  // purposefully not using versioning namespace
     89 {
     90 
     91 class _LIBCPP_EXCEPTION_ABI exception
     92 {
     93 public:
     94     _LIBCPP_INLINE_VISIBILITY exception() _NOEXCEPT {}
     95     virtual ~exception() _NOEXCEPT;
     96     virtual const char* what() const _NOEXCEPT;
     97 };
     98 
     99 class _LIBCPP_EXCEPTION_ABI bad_exception
    100     : public exception
    101 {
    102 public:
    103     _LIBCPP_INLINE_VISIBILITY bad_exception() _NOEXCEPT {}
    104     virtual ~bad_exception() _NOEXCEPT;
    105     virtual const char* what() const _NOEXCEPT;
    106 };
    107 
    108 typedef void (*unexpected_handler)();
    109 _LIBCPP_FUNC_VIS unexpected_handler set_unexpected(unexpected_handler) _NOEXCEPT;
    110 _LIBCPP_FUNC_VIS unexpected_handler get_unexpected() _NOEXCEPT;
    111 _LIBCPP_NORETURN _LIBCPP_FUNC_VIS void unexpected();
    112 
    113 typedef void (*terminate_handler)();
    114 _LIBCPP_FUNC_VIS terminate_handler set_terminate(terminate_handler) _NOEXCEPT;
    115 _LIBCPP_FUNC_VIS terminate_handler get_terminate() _NOEXCEPT;
    116 _LIBCPP_NORETURN _LIBCPP_FUNC_VIS void terminate() _NOEXCEPT;
    117 
    118 _LIBCPP_FUNC_VIS bool uncaught_exception() _NOEXCEPT;
    119 _LIBCPP_FUNC_VIS int uncaught_exceptions() _NOEXCEPT;
    120 
    121 class _LIBCPP_TYPE_VIS exception_ptr;
    122 
    123 _LIBCPP_FUNC_VIS exception_ptr current_exception() _NOEXCEPT;
    124 _LIBCPP_NORETURN _LIBCPP_FUNC_VIS void rethrow_exception(exception_ptr);
    125 
    126 class _LIBCPP_TYPE_VIS exception_ptr
    127 {
    128     void* __ptr_;
    129 public:
    130     _LIBCPP_INLINE_VISIBILITY exception_ptr() _NOEXCEPT : __ptr_() {}
    131     _LIBCPP_INLINE_VISIBILITY exception_ptr(nullptr_t) _NOEXCEPT : __ptr_() {}
    132     exception_ptr(const exception_ptr&) _NOEXCEPT;
    133     exception_ptr& operator=(const exception_ptr&) _NOEXCEPT;
    134     ~exception_ptr() _NOEXCEPT;
    135 
    136     _LIBCPP_INLINE_VISIBILITY
    137     _LIBCPP_EXPLICIT
    138         operator bool() const _NOEXCEPT {return __ptr_ != nullptr;}
    139 
    140     friend _LIBCPP_INLINE_VISIBILITY
    141     bool operator==(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT
    142         {return __x.__ptr_ == __y.__ptr_;}
    143     friend _LIBCPP_INLINE_VISIBILITY
    144     bool operator!=(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT
    145         {return !(__x == __y);}
    146 
    147     friend _LIBCPP_FUNC_VIS exception_ptr current_exception() _NOEXCEPT;
    148     friend _LIBCPP_FUNC_VIS void rethrow_exception(exception_ptr);
    149 };
    150 
    151 template<class _Ep>
    152 exception_ptr
    153 make_exception_ptr(_Ep __e) _NOEXCEPT
    154 {
    155 #ifndef _LIBCPP_NO_EXCEPTIONS
    156     try
    157     {
    158         throw __e;
    159     }
    160     catch (...)
    161     {
    162         return current_exception();
    163     }
    164 #endif  // _LIBCPP_NO_EXCEPTIONS
    165 }
    166 
    167 // nested_exception
    168 
    169 class _LIBCPP_EXCEPTION_ABI nested_exception
    170 {
    171     exception_ptr __ptr_;
    172 public:
    173     nested_exception() _NOEXCEPT;
    174 //     nested_exception(const nested_exception&) noexcept = default;
    175 //     nested_exception& operator=(const nested_exception&) noexcept = default;
    176     virtual ~nested_exception() _NOEXCEPT;
    177 
    178     // access functions
    179     _LIBCPP_NORETURN void rethrow_nested() const;
    180     _LIBCPP_INLINE_VISIBILITY exception_ptr nested_ptr() const _NOEXCEPT {return __ptr_;}
    181 };
    182 
    183 template <class _Tp>
    184 struct __nested
    185     : public _Tp,
    186       public nested_exception
    187 {
    188     _LIBCPP_INLINE_VISIBILITY explicit __nested(const _Tp& __t) : _Tp(__t) {}
    189 };
    190 
    191 template <class _Tp>
    192 _LIBCPP_NORETURN
    193 void
    194 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
    195 throw_with_nested(_Tp&& __t, typename enable_if<
    196                   is_class<typename remove_reference<_Tp>::type>::value &&
    197                   !is_base_of<nested_exception, typename remove_reference<_Tp>::type>::value
    198                   && !__libcpp_is_final<typename remove_reference<_Tp>::type>::value
    199                                     >::type* = 0)
    200 #else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
    201 throw_with_nested (_Tp& __t, typename enable_if<
    202                   is_class<_Tp>::value && !is_base_of<nested_exception, _Tp>::value
    203                                     >::type* = 0)
    204 #endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
    205 {
    206 #ifndef _LIBCPP_NO_EXCEPTIONS
    207     throw __nested<typename remove_reference<_Tp>::type>(_VSTD::forward<_Tp>(__t));
    208 #endif
    209 }
    210 
    211 template <class _Tp>
    212 _LIBCPP_NORETURN
    213 void
    214 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
    215 throw_with_nested(_Tp&& __t, typename enable_if<
    216                   !is_class<typename remove_reference<_Tp>::type>::value ||
    217                   is_base_of<nested_exception, typename remove_reference<_Tp>::type>::value
    218                   || __libcpp_is_final<typename remove_reference<_Tp>::type>::value
    219                                     >::type* = 0)
    220 #else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
    221 throw_with_nested (_Tp& __t, typename enable_if<
    222                   !is_class<_Tp>::value || is_base_of<nested_exception, _Tp>::value
    223                                     >::type* = 0)
    224 #endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
    225 {
    226 #ifndef _LIBCPP_NO_EXCEPTIONS
    227     throw _VSTD::forward<_Tp>(__t);
    228 #endif
    229 }
    230 
    231 template <class _Ep>
    232 inline _LIBCPP_INLINE_VISIBILITY
    233 void
    234 rethrow_if_nested(const _Ep& __e, typename enable_if<
    235                                    is_polymorphic<_Ep>::value
    236                                                    >::type* = 0)
    237 {
    238     const nested_exception* __nep = dynamic_cast<const nested_exception*>(&__e);
    239     if (__nep)
    240         __nep->rethrow_nested();
    241 }
    242 
    243 template <class _Ep>
    244 inline _LIBCPP_INLINE_VISIBILITY
    245 void
    246 rethrow_if_nested(const _Ep&, typename enable_if<
    247                                    !is_polymorphic<_Ep>::value
    248                                                    >::type* = 0)
    249 {
    250 }
    251 
    252 }  // std
    253 
    254 #endif  // _LIBCPP_EXCEPTION
    255