libstdc++-v3/src/c++11/cxx11-ios_failure.cc

   1 // Iostreams base classes -*- C++ -*-
   2
   3 // Copyright (C) 2014-2020 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 //
  26 // ISO C++ 14882:2011: 27.5.3.1.1  Class ios_base::failure
  27 //
  28
  29 #define _GLIBCXX_USE_CXX11_ABI 1
  30 #include <ios>
  31 #include <bits/functexcept.h>
  32 #include <cxxabi.h>
  33
  34 #ifdef _GLIBCXX_USE_NLS
  35 # include <libintl.h>
  36 # define _(msgid)   gettext (msgid)
  37 #else
  38 # define _(msgid)   (msgid)
  39 #endif
  40
  41 #if ! _GLIBCXX_USE_DUAL_ABI
  42 # error This file should not be compiled for this configuration.
  43 #endif
  44
  45 namespace
  46 {
  47   struct io_error_category : std::error_category
  48   {
  49     virtual const char*
  50     name() const noexcept
  51     { return "iostream"; }
  52
  53     _GLIBCXX_DEFAULT_ABI_TAG
  54     virtual std::string message(int __ec) const
  55     {
  56       std::string __msg;
  57       switch (std::io_errc(__ec))
  58       {
  59       case std::io_errc::stream:
  60           __msg = "iostream error";
  61           break;
  62       default:
  63           __msg = "Unknown error";
  64           break;
  65       }
  66       return __msg;
  67     }
  68   };
  69
  70   const io_error_category&
  71   __io_category_instance() noexcept
  72   {
  73     static const io_error_category __ec{};
  74     return __ec;
  75   }
  76
  77 } // namespace
  78
  79 namespace std _GLIBCXX_VISIBILITY(default)
  80 {
  81 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  82
  83   const error_category&
  84   iostream_category() noexcept
  85   { return __io_category_instance(); }
  86
  87   ios_base::failure::failure(const string& __str)
  88   : system_error(io_errc::stream, __str) { }
  89
  90   ios_base::failure::failure(const string& __str, const error_code& __ec)
  91   : system_error(__ec, __str) { }
  92
  93   ios_base::failure::failure(const char* __str, const error_code& __ec)
  94   : system_error(__ec, __str) { }
  95
  96   ios_base::failure::~failure()
  97   { }
  98
  99   const char*
 100   ios_base::failure::what() const throw()
 101   { return runtime_error::what(); }
 102
 103 #if __cpp_rtti
 104   // These functions are defined in src/c++98/ios_failure.cc
 105   extern void __construct_ios_failure(void*, const char*);
 106   extern void __destroy_ios_failure(void*);
 107   extern bool __is_ios_failure_handler(const __cxxabiv1::__class_type_info*);
 108
 109   // The type thrown to report errors during stream buffer operations.
 110   // In addition to the ios::failure[abi:cxx11] base class it also has a
 111   // member of the gcc4-compatible ios::failure type (in an opaque buffer).
 112   struct __ios_failure : std::ios::failure
 113   {
 114     __ios_failure(const char* s) : failure(s)
 115     { __construct_ios_failure(buf, runtime_error::what()); }
 116
 117     __ios_failure(const char* s, int e) : failure(s, to_error_code(e))
 118     { __construct_ios_failure(buf, runtime_error::what()); }
 119
 120     ~__ios_failure()
 121     { __destroy_ios_failure(buf); }
 122
 123     // Use std::runtime_error as a proxy for the gcc4-compatible ios::failure
 124     // (which can't be declared here because _GLIBCXX_USE_CXX11_ABI == 1).
 125     // There are assertions in src/c++98/ios_failure.cc to ensure the size
 126     // and alignment assumptions are valid.
 127     alignas(runtime_error) unsigned char buf[sizeof(runtime_error)];
 128
 129     static error_code
 130     to_error_code(int e)
 131     { return e ? error_code(e, system_category()) : io_errc::stream; }
 132   };
 133
 134   // Custom type info for __ios_failure.
 135   class __iosfail_type_info : __cxxabiv1::__si_class_type_info
 136   {
 137     ~__iosfail_type_info();
 138
 139     bool
 140     __do_upcast (const __class_type_info *dst_type,
 141                  void **obj_ptr) const override;
 142   };
 143
 144   __iosfail_type_info::~__iosfail_type_info() = default;
 145
 146   // This function gets called to see if an exception of type
 147   // __ios_failure can be upcast to the type in a catch handler.
 148   bool
 149   __iosfail_type_info::__do_upcast(const __class_type_info *dst_type,
 150                                    void **obj_ptr) const
 151   {
 152     // If the handler is for the gcc4-compatible ios::failure type then
 153     // catch the object stored in __ios_failure::buf instead of
 154     // the __ios_failure exception object itself.
 155     if (__is_ios_failure_handler(dst_type))
 156       {
 157         *obj_ptr = static_cast<__ios_failure*>(*obj_ptr)->buf;
 158         return true;
 159       }
 160     // Otherwise proceed as normal to see if the handler matches.
 161     return __class_type_info::__do_upcast(dst_type, obj_ptr);
 162   }
 163 #else // ! __cpp_rtti
 164   using __ios_failure = ios::failure;
 165 #endif
 166
 167   void
 168   __throw_ios_failure(const char* __s __attribute__((unused)))
 169   { _GLIBCXX_THROW_OR_ABORT(__ios_failure(_(__s))); }
 170
 171   void
 172   __throw_ios_failure(const char* str __attribute__((unused)),
 173                       int err __attribute__((unused)))
 174   { _GLIBCXX_THROW_OR_ABORT(__ios_failure(_(str), err)); }
 175
 176 _GLIBCXX_END_NAMESPACE_VERSION
 177 } // namespace