libcxx/include/__exception/exception_ptr.h

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef _LIBCPP___EXCEPTION_EXCEPTION_PTR_H
  10 #define _LIBCPP___EXCEPTION_EXCEPTION_PTR_H
  11
  12 #include <__availability>
  13 #include <__config>
  14 #include <__exception/operations.h>
  15 #include <__memory/addressof.h>
  16 #include <__memory/construct_at.h>
  17 #include <__type_traits/decay.h>
  18 #include <cstddef>
  19 #include <cstdlib>
  20 #include <new>
  21 #include <typeinfo>
  22
  23 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  24 #  pragma GCC system_header
  25 #endif
  26
  27 #ifndef _LIBCPP_ABI_MICROSOFT
  28
  29 namespace __cxxabiv1 {
  30
  31 extern "C" {
  32 _LIBCPP_OVERRIDABLE_FUNC_VIS void* __cxa_allocate_exception(size_t) throw();
  33 _LIBCPP_OVERRIDABLE_FUNC_VIS void __cxa_free_exception(void*) throw();
  34
  35 struct __cxa_exception;
  36 _LIBCPP_OVERRIDABLE_FUNC_VIS __cxa_exception* __cxa_init_primary_exception(
  37     void*,
  38     std::type_info*,
  39     void(
  40 #  if defined(_WIN32)
  41         __thiscall
  42 #  endif
  43             *)(void*)) throw();
  44 }
  45
  46 } // namespace __cxxabiv1
  47
  48 #endif
  49
  50 namespace std { // purposefully not using versioning namespace
  51
  52 #ifndef _LIBCPP_ABI_MICROSOFT
  53
  54 class _LIBCPP_EXPORTED_FROM_ABI exception_ptr {
  55   void* __ptr_;
  56
  57   static exception_ptr __from_native_exception_pointer(void*) _NOEXCEPT;
  58
  59   template <class _Ep>
  60   friend _LIBCPP_HIDE_FROM_ABI exception_ptr make_exception_ptr(_Ep) _NOEXCEPT;
  61
  62 public:
  63   _LIBCPP_HIDE_FROM_ABI exception_ptr() _NOEXCEPT : __ptr_() {}
  64   _LIBCPP_HIDE_FROM_ABI exception_ptr(nullptr_t) _NOEXCEPT : __ptr_() {}
  65
  66   exception_ptr(const exception_ptr&) _NOEXCEPT;
  67   exception_ptr& operator=(const exception_ptr&) _NOEXCEPT;
  68   ~exception_ptr() _NOEXCEPT;
  69
  70   _LIBCPP_HIDE_FROM_ABI explicit operator bool() const _NOEXCEPT { return __ptr_ != nullptr; }
  71
  72   friend _LIBCPP_HIDE_FROM_ABI bool operator==(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT {
  73     return __x.__ptr_ == __y.__ptr_;
  74   }
  75
  76   friend _LIBCPP_HIDE_FROM_ABI bool operator!=(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT {
  77     return !(__x == __y);
  78   }
  79
  80   friend _LIBCPP_EXPORTED_FROM_ABI exception_ptr current_exception() _NOEXCEPT;
  81   friend _LIBCPP_EXPORTED_FROM_ABI void rethrow_exception(exception_ptr);
  82 };
  83
  84 template <class _Ep>
  85 _LIBCPP_HIDE_FROM_ABI exception_ptr make_exception_ptr(_Ep __e) _NOEXCEPT {
  86 #  ifndef _LIBCPP_HAS_NO_EXCEPTIONS
  87 #    if _LIBCPP_AVAILABILITY_HAS_INIT_PRIMARY_EXCEPTION && __cplusplus >= 201103L
  88   using _Ep2 = __decay_t<_Ep>;
  89
  90   void* __ex = __cxxabiv1::__cxa_allocate_exception(sizeof(_Ep));
  91   (void)__cxxabiv1::__cxa_init_primary_exception(__ex, const_cast<std::type_info*>(&typeid(_Ep)), [](void* __p) {
  92     std::__destroy_at(static_cast<_Ep2*>(__p));
  93   });
  94
  95   try {
  96     ::new (__ex) _Ep2(__e);
  97     return exception_ptr::__from_native_exception_pointer(__ex);
  98   } catch (...) {
  99     __cxxabiv1::__cxa_free_exception(__ex);
 100     return current_exception();
 101   }
 102 #    else
 103   try {
 104     throw __e;
 105   } catch (...) {
 106     return current_exception();
 107   }
 108 #    endif
 109 #  else
 110   ((void)__e);
 111   std::abort();
 112 #  endif
 113 }
 114
 115 #else // _LIBCPP_ABI_MICROSOFT
 116
 117 class _LIBCPP_EXPORTED_FROM_ABI exception_ptr {
 118   _LIBCPP_DIAGNOSTIC_PUSH
 119   _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wunused-private-field")
 120   void* __ptr1_;
 121   void* __ptr2_;
 122   _LIBCPP_DIAGNOSTIC_POP
 123
 124 public:
 125   exception_ptr() _NOEXCEPT;
 126   exception_ptr(nullptr_t) _NOEXCEPT;
 127   exception_ptr(const exception_ptr& __other) _NOEXCEPT;
 128   exception_ptr& operator=(const exception_ptr& __other) _NOEXCEPT;
 129   exception_ptr& operator=(nullptr_t) _NOEXCEPT;
 130   ~exception_ptr() _NOEXCEPT;
 131   explicit operator bool() const _NOEXCEPT;
 132 };
 133
 134 _LIBCPP_EXPORTED_FROM_ABI bool operator==(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT;
 135
 136 inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const exception_ptr& __x, const exception_ptr& __y) _NOEXCEPT {
 137   return !(__x == __y);
 138 }
 139
 140 _LIBCPP_EXPORTED_FROM_ABI void swap(exception_ptr&, exception_ptr&) _NOEXCEPT;
 141
 142 _LIBCPP_EXPORTED_FROM_ABI exception_ptr __copy_exception_ptr(void* __except, const void* __ptr);
 143 _LIBCPP_EXPORTED_FROM_ABI exception_ptr current_exception() _NOEXCEPT;
 144 _LIBCPP_NORETURN _LIBCPP_EXPORTED_FROM_ABI void rethrow_exception(exception_ptr);
 145
 146 // This is a built-in template function which automagically extracts the required
 147 // information.
 148 template <class _E>
 149 void* __GetExceptionInfo(_E);
 150
 151 template <class _Ep>
 152 _LIBCPP_HIDE_FROM_ABI exception_ptr make_exception_ptr(_Ep __e) _NOEXCEPT {
 153   return __copy_exception_ptr(std::addressof(__e), __GetExceptionInfo(__e));
 154 }
 155
 156 #endif // _LIBCPP_ABI_MICROSOFT
 157 } // namespace std
 158
 159 #endif // _LIBCPP___EXCEPTION_EXCEPTION_PTR_H