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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 
     53 typedef unspecified exception_ptr;
     54 
     55 exception_ptr current_exception() noexcept;
     56 void rethrow_exception [[noreturn]] (exception_ptr p);
     57 template<class E> exception_ptr make_exception_ptr(E e) noexcept;
     58 
     59 class nested_exception
     60 {
     61 public:
     62     nested_exception() noexcept;
     63     nested_exception(const nested_exception&) noexcept = default;
     64     nested_exception& operator=(const nested_exception&) noexcept = default;
     65     virtual ~nested_exception() = default;
     66 
     67     // access functions
     68     [[noreturn]] void rethrow_nested() const;
     69     exception_ptr nested_ptr() const noexcept;
     70 };
     71 
     72 template <class T> [[noreturn]] void throw_with_nested(T&& t);
     73 template <class E> void rethrow_if_nested(const E& e);
     74 
     75 }  // std
     76 
     77 */
     78 
     79 #include <__config>
     80 #include <cstddef>
     81 #include <type_traits>
     82 
     83 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
     84 #pragma GCC system_header
     85 #endif
     86 
     87 namespace std  // purposefully not using versioning namespace
     88 {
     89 
     90 class _LIBCPP_EXCEPTION_ABI exception
     91 {
     92 public:
     93     _LIBCPP_INLINE_VISIBILITY exception() _NOEXCEPT {}
     94     virtual ~exception() _NOEXCEPT;
     95     virtual const char* what() const _NOEXCEPT;
     96 };
     97 
     98 class _LIBCPP_EXCEPTION_ABI bad_exception
     99     : public exception
    100 {
    101 public:
    102     _LIBCPP_INLINE_VISIBILITY bad_exception() _NOEXCEPT {}
    103     virtual ~bad_exception() _NOEXCEPT;
    104     virtual const char* what() const _NOEXCEPT;
    105 };
    106 
    107 typedef void (*unexpected_handler)();
    108 _LIBCPP_FUNC_VIS unexpected_handler set_unexpected(unexpected_handler) _NOEXCEPT;
    109 _LIBCPP_FUNC_VIS unexpected_handler get_unexpected() _NOEXCEPT;
    110 _LIBCPP_NORETURN _LIBCPP_FUNC_VIS void unexpected();
    111 
    112 typedef void (*terminate_handler)();
    113 _LIBCPP_FUNC_VIS terminate_handler set_terminate(terminate_handler) _NOEXCEPT;
    114 _LIBCPP_FUNC_VIS terminate_handler get_terminate() _NOEXCEPT;
    115 #if __cplusplus >= 201103L
    116 _LIBCPP_NORETURN _LIBCPP_FUNC_VIS void terminate() _NOEXCEPT;
    117 #else
    118 _LIBCPP_NORETURN _LIBCPP_FUNC_VIS void terminate();
    119 #endif
    120 
    121 _LIBCPP_FUNC_VIS bool uncaught_exception() _NOEXCEPT;
    122 
    123 class _LIBCPP_TYPE_VIS exception_ptr;
    124 
    125 _LIBCPP_FUNC_VIS exception_ptr current_exception() _NOEXCEPT;
    126 _LIBCPP_NORETURN _LIBCPP_FUNC_VIS void rethrow_exception(exception_ptr);
    127 
    128 class _LIBCPP_TYPE_VIS exception_ptr
    129 {
    130     void* __ptr_;
    131 public:
    132     _LIBCPP_INLINE_VISIBILITY exception_ptr() _NOEXCEPT : __ptr_() {}
    133     _LIBCPP_INLINE_VISIBILITY exception_ptr(nullptr_t) _NOEXCEPT : __ptr_() {}
    134     exception_ptr(const exception_ptr&) _NOEXCEPT;
    135     exception_ptr& operator=(const exception_ptr&) _NOEXCEPT;
    136     ~exception_ptr() _NOEXCEPT;
    137 
    138     _LIBCPP_INLINE_VISIBILITY
    139     _LIBCPP_EXPLICIT
    140         operator bool() const _NOEXCEPT {return __ptr_ != nullptr;}
    141 
    142     friend _LIBCPP_INLINE_VISIBILITY
    143     bool operator==(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT
    144         {return __x.__ptr_ == __y.__ptr_;}
    145     friend _LIBCPP_INLINE_VISIBILITY
    146     bool operator!=(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT
    147         {return !(__x == __y);}
    148 
    149     friend _LIBCPP_FUNC_VIS exception_ptr current_exception() _NOEXCEPT;
    150     friend _LIBCPP_FUNC_VIS void rethrow_exception(exception_ptr);
    151 };
    152 
    153 template<class _Ep>
    154 exception_ptr
    155 make_exception_ptr(_Ep __e) _NOEXCEPT
    156 {
    157 #ifndef _LIBCPP_NO_EXCEPTIONS
    158     try
    159     {
    160         throw __e;
    161     }
    162     catch (...)
    163     {
    164         return current_exception();
    165     }
    166 #endif  // _LIBCPP_NO_EXCEPTIONS
    167 }
    168 
    169 // nested_exception
    170 
    171 class _LIBCPP_EXCEPTION_ABI nested_exception
    172 {
    173     exception_ptr __ptr_;
    174 public:
    175     nested_exception() _NOEXCEPT;
    176 //     nested_exception(const nested_exception&) noexcept = default;
    177 //     nested_exception& operator=(const nested_exception&) noexcept = default;
    178     virtual ~nested_exception() _NOEXCEPT;
    179 
    180     // access functions
    181     _LIBCPP_NORETURN void rethrow_nested() const;
    182     _LIBCPP_INLINE_VISIBILITY exception_ptr nested_ptr() const _NOEXCEPT {return __ptr_;}
    183 };
    184 
    185 template <class _Tp>
    186 struct __nested
    187     : public _Tp,
    188       public nested_exception
    189 {
    190     _LIBCPP_INLINE_VISIBILITY explicit __nested(const _Tp& __t) : _Tp(__t) {}
    191 };
    192 
    193 template <class _Tp>
    194 _LIBCPP_NORETURN
    195 void
    196 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
    197 throw_with_nested(_Tp&& __t, typename enable_if<
    198                   is_class<typename remove_reference<_Tp>::type>::value &&
    199                   !is_base_of<nested_exception, typename remove_reference<_Tp>::type>::value
    200                                     >::type* = 0)
    201 #else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
    202 throw_with_nested (_Tp& __t, typename enable_if<
    203                   is_class<_Tp>::value && !is_base_of<nested_exception, _Tp>::value
    204                                     >::type* = 0)
    205 #endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
    206 {
    207 #ifndef _LIBCPP_NO_EXCEPTIONS
    208     throw __nested<typename remove_reference<_Tp>::type>(_VSTD::forward<_Tp>(__t));
    209 #endif
    210 }
    211 
    212 template <class _Tp>
    213 _LIBCPP_NORETURN
    214 void
    215 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
    216 throw_with_nested(_Tp&& __t, typename enable_if<
    217                   !is_class<typename remove_reference<_Tp>::type>::value ||
    218                   is_base_of<nested_exception, 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