libstdc++-v3/libsupc++/exception_ptr.h

   1 // Exception Handling support header (exception_ptr class) for -*- C++ -*-
   2
   3 // Copyright (C) 2008-2017 Free Software Foundation, Inc.
   4 //
   5 // This file is part of GCC.
   6 //
   7 // GCC is free software; you can redistribute it and/or modify
   8 // it under the terms of the GNU General Public License as published by
   9 // the Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11 //
  12 // GCC is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16 //
  17 // Under Section 7 of GPL version 3, you are granted additional
  18 // permissions described in the GCC Runtime Library Exception, version
  19 // 3.1, as published by the Free Software Foundation.
  20
  21 // You should have received a copy of the GNU General Public License and
  22 // a copy of the GCC Runtime Library Exception along with this program;
  23 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 // <http://www.gnu.org/licenses/>.
  25
  26 /** @file bits/exception_ptr.h
  27  *  This is an internal header file, included by other library headers.
  28  *  Do not attempt to use it directly. @headername{exception}
  29  */
  30
  31 #ifndef _EXCEPTION_PTR_H
  32 #define _EXCEPTION_PTR_H
  33
  34 #pragma GCC visibility push(default)
  35
  36 #include <bits/c++config.h>
  37 #include <bits/exception_defines.h>
  38 #include <bits/cxxabi_init_exception.h>
  39 #include <typeinfo>
  40 #include <new>
  41
  42 #if ATOMIC_INT_LOCK_FREE < 2
  43 #  error This platform does not support exception propagation.
  44 #endif
  45
  46 extern "C++" {
  47
  48 namespace std
  49 {
  50   class type_info;
  51
  52   /**
  53    * @addtogroup exceptions
  54    * @{
  55    */
  56   namespace __exception_ptr
  57   {
  58     class exception_ptr;
  59   }
  60
  61   using __exception_ptr::exception_ptr;
  62
  63   /** Obtain an exception_ptr to the currently handled exception. If there
  64    *  is none, or the currently handled exception is foreign, return the null
  65    *  value.
  66    */
  67   exception_ptr current_exception() _GLIBCXX_USE_NOEXCEPT;
  68
  69   template<typename _Ex>
  70   exception_ptr make_exception_ptr(_Ex) _GLIBCXX_USE_NOEXCEPT;
  71
  72   /// Throw the object pointed to by the exception_ptr.
  73   void rethrow_exception(exception_ptr) __attribute__ ((__noreturn__));
  74
  75   namespace __exception_ptr
  76   {
  77     using std::rethrow_exception;
  78
  79     /**
  80      *  @brief An opaque pointer to an arbitrary exception.
  81      *  @ingroup exceptions
  82      */
  83     class exception_ptr
  84     {
  85       void* _M_exception_object;
  86
  87       explicit exception_ptr(void* __e) _GLIBCXX_USE_NOEXCEPT;
  88
  89       void _M_addref() _GLIBCXX_USE_NOEXCEPT;
  90       void _M_release() _GLIBCXX_USE_NOEXCEPT;
  91
  92       void *_M_get() const _GLIBCXX_NOEXCEPT __attribute__ ((__pure__));
  93
  94       friend exception_ptr std::current_exception() _GLIBCXX_USE_NOEXCEPT;
  95       friend void std::rethrow_exception(exception_ptr);
  96       template<typename _Ex>
  97       friend exception_ptr std::make_exception_ptr(_Ex) _GLIBCXX_USE_NOEXCEPT;
  98
  99     public:
 100       exception_ptr() _GLIBCXX_USE_NOEXCEPT;
 101
 102       exception_ptr(const exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
 103
 104 #if __cplusplus >= 201103L
 105       exception_ptr(nullptr_t) noexcept
 106       : _M_exception_object(0)
 107       { }
 108
 109       exception_ptr(exception_ptr&& __o) noexcept
 110       : _M_exception_object(__o._M_exception_object)
 111       { __o._M_exception_object = 0; }
 112 #endif
 113
 114 #if (__cplusplus < 201103L) || defined (_GLIBCXX_EH_PTR_COMPAT)
 115       typedef void (exception_ptr::*__safe_bool)();
 116
 117       // For construction from nullptr or 0.
 118       exception_ptr(__safe_bool) _GLIBCXX_USE_NOEXCEPT;
 119 #endif
 120
 121       exception_ptr&
 122       operator=(const exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
 123
 124 #if __cplusplus >= 201103L
 125       exception_ptr&
 126       operator=(exception_ptr&& __o) noexcept
 127       {
 128         exception_ptr(static_cast<exception_ptr&&>(__o)).swap(*this);
 129         return *this;
 130       }
 131 #endif
 132
 133       ~exception_ptr() _GLIBCXX_USE_NOEXCEPT;
 134
 135       void
 136       swap(exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
 137
 138 #ifdef _GLIBCXX_EH_PTR_COMPAT
 139       // Retained for compatibility with CXXABI_1.3.
 140       void _M_safe_bool_dummy() _GLIBCXX_USE_NOEXCEPT
 141         __attribute__ ((__const__));
 142       bool operator!() const _GLIBCXX_USE_NOEXCEPT
 143         __attribute__ ((__pure__));
 144       operator __safe_bool() const _GLIBCXX_USE_NOEXCEPT;
 145 #endif
 146
 147 #if __cplusplus >= 201103L
 148       explicit operator bool() const
 149       { return _M_exception_object; }
 150 #endif
 151
 152       friend bool
 153       operator==(const exception_ptr&, const exception_ptr&)
 154         _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
 155
 156       const class std::type_info*
 157       __cxa_exception_type() const _GLIBCXX_USE_NOEXCEPT
 158         __attribute__ ((__pure__));
 159     };
 160
 161     bool
 162     operator==(const exception_ptr&, const exception_ptr&)
 163       _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
 164
 165     bool
 166     operator!=(const exception_ptr&, const exception_ptr&)
 167       _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
 168
 169     inline void
 170     swap(exception_ptr& __lhs, exception_ptr& __rhs)
 171     { __lhs.swap(__rhs); }
 172
 173     template<typename _Ex>
 174       inline void
 175       __dest_thunk(void* x)
 176       { static_cast<_Ex*>(x)->~_Ex(); }
 177
 178   } // namespace __exception_ptr
 179
 180   /// Obtain an exception_ptr pointing to a copy of the supplied object.
 181   template<typename _Ex>
 182     exception_ptr
 183     make_exception_ptr(_Ex __ex) _GLIBCXX_USE_NOEXCEPT
 184     {
 185 #if __cpp_exceptions
 186       try
 187         {
 188 #if __cpp_rtti && !_GLIBCXX_HAVE_CDTOR_CALLABI
 189           void *__e = __cxxabiv1::__cxa_allocate_exception(sizeof(_Ex));
 190           (void)__cxxabiv1::__cxa_init_primary_exception(
 191               __e, const_cast<std::type_info*>(&typeid(__ex)),
 192               __exception_ptr::__dest_thunk<_Ex>);
 193           ::new (__e) _Ex(__ex);
 194           return exception_ptr(__e);
 195 #else
 196           throw __ex;
 197 #endif
 198         }
 199       catch(...)
 200         {
 201           return current_exception();
 202         }
 203 #else
 204       return exception_ptr();
 205 #endif
 206     }
 207
 208   // _GLIBCXX_RESOLVE_LIB_DEFECTS
 209   // 1130. copy_exception name misleading
 210   /// Obtain an exception_ptr pointing to a copy of the supplied object.
 211   /// This function is deprecated, use std::make_exception_ptr instead.
 212   template<typename _Ex>
 213     exception_ptr
 214     copy_exception(_Ex __ex) _GLIBCXX_USE_NOEXCEPT _GLIBCXX_DEPRECATED;
 215
 216   template<typename _Ex>
 217     exception_ptr
 218     copy_exception(_Ex __ex) _GLIBCXX_USE_NOEXCEPT
 219     { return std::make_exception_ptr<_Ex>(__ex); }
 220
 221   // @} group exceptions
 222 } // namespace std
 223
 224 } // extern "C++"
 225
 226 #pragma GCC visibility pop
 227
 228 #endif