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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_VISIBLE unexpected_handler set_unexpected(unexpected_handler) _NOEXCEPT;
    109 _LIBCPP_VISIBLE unexpected_handler get_unexpected() _NOEXCEPT;
    110 _LIBCPP_NORETURN _LIBCPP_VISIBLE void unexpected();
    111 
    112 typedef void (*terminate_handler)();
    113 _LIBCPP_VISIBLE terminate_handler set_terminate(terminate_handler) _NOEXCEPT;
    114 _LIBCPP_VISIBLE terminate_handler get_terminate() _NOEXCEPT;
    115 _LIBCPP_NORETURN _LIBCPP_VISIBLE void terminate() _NOEXCEPT;
    116 
    117 _LIBCPP_VISIBLE bool uncaught_exception() _NOEXCEPT;
    118 
    119 class _LIBCPP_VISIBLE exception_ptr;
    120 
    121 exception_ptr current_exception() _NOEXCEPT;
    122 _LIBCPP_NORETURN void rethrow_exception(exception_ptr);
    123 
    124 class _LIBCPP_VISIBLE exception_ptr
    125 {
    126     void* __ptr_;
    127 public:
    128     _LIBCPP_INLINE_VISIBILITY exception_ptr() _NOEXCEPT : __ptr_() {}
    129     _LIBCPP_INLINE_VISIBILITY exception_ptr(nullptr_t) _NOEXCEPT : __ptr_() {}
    130     exception_ptr(const exception_ptr&) _NOEXCEPT;
    131     exception_ptr& operator=(const exception_ptr&) _NOEXCEPT;
    132     ~exception_ptr() _NOEXCEPT;
    133 
    134     _LIBCPP_INLINE_VISIBILITY
    135     _LIBCPP_EXPLICIT
    136         operator bool() const _NOEXCEPT {return __ptr_ != nullptr;}
    137 
    138     friend _LIBCPP_INLINE_VISIBILITY
    139     bool operator==(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT
    140         {return __x.__ptr_ == __y.__ptr_;}
    141     friend _LIBCPP_INLINE_VISIBILITY
    142     bool operator!=(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT
    143         {return !(__x == __y);}
    144 
    145     friend exception_ptr current_exception() _NOEXCEPT;
    146     friend void rethrow_exception(exception_ptr);
    147 };
    148 
    149 template<class _Ep>
    150 exception_ptr
    151 make_exception_ptr(_Ep __e) _NOEXCEPT
    152 {
    153 #ifndef _LIBCPP_NO_EXCEPTIONS
    154     try
    155     {
    156         throw __e;
    157     }
    158     catch (...)
    159     {
    160         return current_exception();
    161     }
    162 #endif  // _LIBCPP_NO_EXCEPTIONS
    163 }
    164 
    165 // nested_exception
    166 
    167 class _LIBCPP_EXCEPTION_ABI nested_exception
    168 {
    169     exception_ptr __ptr_;
    170 public:
    171     nested_exception() _NOEXCEPT;
    172 //     nested_exception(const nested_exception&) noexcept = default;
    173 //     nested_exception& operator=(const nested_exception&) noexcept = default;
    174     virtual ~nested_exception() _NOEXCEPT;
    175 
    176     // access functions
    177     _LIBCPP_NORETURN void rethrow_nested() const;
    178     _LIBCPP_INLINE_VISIBILITY exception_ptr nested_ptr() const _NOEXCEPT {return __ptr_;}
    179 };
    180 
    181 template <class _Tp>
    182 struct __nested
    183     : public _Tp,
    184       public nested_exception
    185 {
    186     _LIBCPP_INLINE_VISIBILITY explicit __nested(const _Tp& __t) : _Tp(__t) {}
    187 };
    188 
    189 template <class _Tp>
    190 _LIBCPP_NORETURN
    191 void
    192 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
    193 throw_with_nested(_Tp&& __t, typename enable_if<
    194                   is_class<typename remove_reference<_Tp>::type>::value &&
    195                   !is_base_of<nested_exception, typename remove_reference<_Tp>::type>::value
    196                                     >::type* = 0)
    197 #else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
    198 throw_with_nested (_Tp& __t, typename enable_if<
    199                   is_class<_Tp>::value && !is_base_of<nested_exception, _Tp>::value
    200                                     >::type* = 0)
    201 #endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
    202 {
    203 #ifndef _LIBCPP_NO_EXCEPTIONS
    204     throw __nested<typename remove_reference<_Tp>::type>(_VSTD::forward<_Tp>(__t));
    205 #endif
    206 }
    207 
    208 template <class _Tp>
    209 _LIBCPP_NORETURN
    210 void
    211 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
    212 throw_with_nested(_Tp&& __t, typename enable_if<
    213                   !is_class<typename remove_reference<_Tp>::type>::value ||
    214                   is_base_of<nested_exception, typename remove_reference<_Tp>::type>::value
    215                                     >::type* = 0)
    216 #else  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
    217 throw_with_nested (_Tp& __t, typename enable_if<
    218                   !is_class<_Tp>::value || is_base_of<nested_exception, _Tp>::value
    219                                     >::type* = 0)
    220 #endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
    221 {
    222 #ifndef _LIBCPP_NO_EXCEPTIONS
    223     throw _VSTD::forward<_Tp>(__t);
    224 #endif
    225 }
    226 
    227 template <class _Ep>
    228 inline _LIBCPP_INLINE_VISIBILITY
    229 void
    230 rethrow_if_nested(const _Ep& __e, typename enable_if<
    231                                    is_polymorphic<_Ep>::value
    232                                                    >::type* = 0)
    233 {
    234     const nested_exception* __nep = dynamic_cast<const nested_exception*>(&__e);
    235     if (__nep)
    236         __nep->rethrow_nested();
    237 }
    238 
    239 template <class _Ep>
    240 inline _LIBCPP_INLINE_VISIBILITY
    241 void
    242 rethrow_if_nested(const _Ep&, typename enable_if<
    243                                    !is_polymorphic<_Ep>::value
    244                                                    >::type* = 0)
    245 {
    246 }
    247 
    248 }  // std
    249 
    250 #endif  // _LIBCPP_EXCEPTION
    251