1 // Exception Handling support header (exception_ptr class) for -*- C++ -*-
2 
3 // Copyright (C) 2008-2018 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 extern "C++" {
43 
44 namespace std
45 {
46   class type_info;
47 
48   /**
49    * @addtogroup exceptions
50    * @{
51    */
52   namespace __exception_ptr
53   {
54     class exception_ptr;
55   }
56 
57   using __exception_ptr::exception_ptr;
58 
59   /** Obtain an exception_ptr to the currently handled exception. If there
60    *  is none, or the currently handled exception is foreign, return the null
61    *  value.
62    */
63   exception_ptr current_exception() _GLIBCXX_USE_NOEXCEPT;
64 
65   template<typename _Ex>
66   exception_ptr make_exception_ptr(_Ex) _GLIBCXX_USE_NOEXCEPT;
67 
68   /// Throw the object pointed to by the exception_ptr.
69   void rethrow_exception(exception_ptr) __attribute__ ((__noreturn__));
70 
71   namespace __exception_ptr
72   {
73     using std::rethrow_exception;
74 
75     /**
76      *  @brief An opaque pointer to an arbitrary exception.
77      *  @ingroup exceptions
78      */
79     class exception_ptr
80     {
81       void* _M_exception_object;
82 
83       explicit exception_ptr(void* __e) _GLIBCXX_USE_NOEXCEPT;
84 
85       void _M_addref() _GLIBCXX_USE_NOEXCEPT;
86       void _M_release() _GLIBCXX_USE_NOEXCEPT;
87 
88       void *_M_get() const _GLIBCXX_NOEXCEPT __attribute__ ((__pure__));
89 
90       friend exception_ptr std::current_exception() _GLIBCXX_USE_NOEXCEPT;
91       friend void std::rethrow_exception(exception_ptr);
92       template<typename _Ex>
93       friend exception_ptr std::make_exception_ptr(_Ex) _GLIBCXX_USE_NOEXCEPT;
94 
95     public:
96       exception_ptr() _GLIBCXX_USE_NOEXCEPT;
97 
98       exception_ptr(const exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
99 
100 #if __cplusplus >= 201103L
exception_ptr(nullptr_t)101       exception_ptr(nullptr_t) noexcept
102       : _M_exception_object(0)
103       { }
104 
exception_ptr(exception_ptr && __o)105       exception_ptr(exception_ptr&& __o) noexcept
106       : _M_exception_object(__o._M_exception_object)
107       { __o._M_exception_object = 0; }
108 #endif
109 
110 #if (__cplusplus < 201103L) || defined (_GLIBCXX_EH_PTR_COMPAT)
111       typedef void (exception_ptr::*__safe_bool)();
112 
113       // For construction from nullptr or 0.
114       exception_ptr(__safe_bool) _GLIBCXX_USE_NOEXCEPT;
115 #endif
116 
117       exception_ptr&
118       operator=(const exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
119 
120 #if __cplusplus >= 201103L
121       exception_ptr&
122       operator=(exception_ptr&& __o) noexcept
123       {
124         exception_ptr(static_cast<exception_ptr&&>(__o)).swap(*this);
125         return *this;
126       }
127 #endif
128 
129       ~exception_ptr() _GLIBCXX_USE_NOEXCEPT;
130 
131       void
132       swap(exception_ptr&) _GLIBCXX_USE_NOEXCEPT;
133 
134 #ifdef _GLIBCXX_EH_PTR_COMPAT
135       // Retained for compatibility with CXXABI_1.3.
136       void _M_safe_bool_dummy() _GLIBCXX_USE_NOEXCEPT
137 	__attribute__ ((__const__));
138       bool operator!() const _GLIBCXX_USE_NOEXCEPT
139 	__attribute__ ((__pure__));
140       operator __safe_bool() const _GLIBCXX_USE_NOEXCEPT;
141 #endif
142 
143 #if __cplusplus >= 201103L
144       explicit operator bool() const
145       { return _M_exception_object; }
146 #endif
147 
148       friend bool
149       operator==(const exception_ptr&, const exception_ptr&)
150 	_GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
151 
152       const class std::type_info*
153       __cxa_exception_type() const _GLIBCXX_USE_NOEXCEPT
154 	__attribute__ ((__pure__));
155     };
156 
157     bool
158     operator==(const exception_ptr&, const exception_ptr&)
159       _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
160 
161     bool
162     operator!=(const exception_ptr&, const exception_ptr&)
163       _GLIBCXX_USE_NOEXCEPT __attribute__ ((__pure__));
164 
165     inline void
swap(exception_ptr & __lhs,exception_ptr & __rhs)166     swap(exception_ptr& __lhs, exception_ptr& __rhs)
167     { __lhs.swap(__rhs); }
168 
169     template<typename _Ex>
170       inline void
__dest_thunk(void * __x)171       __dest_thunk(void* __x)
172       { static_cast<_Ex*>(__x)->~_Ex(); }
173 
174   } // namespace __exception_ptr
175 
176   /// Obtain an exception_ptr pointing to a copy of the supplied object.
177   template<typename _Ex>
178     exception_ptr
make_exception_ptr(_Ex __ex)179     make_exception_ptr(_Ex __ex) _GLIBCXX_USE_NOEXCEPT
180     {
181 #if __cpp_exceptions && __cpp_rtti && !_GLIBCXX_HAVE_CDTOR_CALLABI
182       void* __e = __cxxabiv1::__cxa_allocate_exception(sizeof(_Ex));
183       (void) __cxxabiv1::__cxa_init_primary_exception(
184 	  __e, const_cast<std::type_info*>(&typeid(__ex)),
185 	  __exception_ptr::__dest_thunk<_Ex>);
186       try
187 	{
188           ::new (__e) _Ex(__ex);
189           return exception_ptr(__e);
190 	}
191       catch(...)
192 	{
193 	  __cxxabiv1::__cxa_free_exception(__e);
194 	  return current_exception();
195 	}
196 #elif __cpp_exceptions
197       try
198 	{
199           throw __ex;
200 	}
201       catch(...)
202 	{
203 	  return current_exception();
204 	}
205 #else // no RTTI and no exceptions
206       return exception_ptr();
207 #endif
208     }
209 
210   // @} group exceptions
211 } // namespace std
212 
213 } // extern "C++"
214 
215 #pragma GCC visibility pop
216 
217 #endif
218