1// Iostreams base classes -*- C++ -*-
2
3// Copyright (C) 2014-2022 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#if __has_cpp_attribute(clang::require_constant_initialization)
46#  define __constinit [[clang::require_constant_initialization]]
47#endif
48
49namespace
50{
51  struct io_error_category final : std::error_category
52  {
53    const char*
54    name() const noexcept final
55    { return "iostream"; }
56
57    _GLIBCXX_DEFAULT_ABI_TAG
58    std::string
59    message(int __ec) const final
60    {
61      std::string __msg;
62      switch (std::io_errc(__ec))
63      {
64      case std::io_errc::stream:
65          __msg = "iostream error";
66          break;
67      default:
68          __msg = "Unknown error";
69          break;
70      }
71      return __msg;
72    }
73  };
74
75  struct constant_init
76  {
77    union {
78      unsigned char unused;
79      io_error_category cat;
80    };
81    constexpr constant_init() : cat() { }
82    ~constant_init() { /* do nothing, union member is not destroyed */ }
83  };
84
85  __constinit constant_init io_category_instance{};
86} // namespace
87
88namespace std _GLIBCXX_VISIBILITY(default)
89{
90_GLIBCXX_BEGIN_NAMESPACE_VERSION
91
92  const error_category&
93  iostream_category() noexcept
94  { return io_category_instance.cat; }
95
96  ios_base::failure::failure(const string& __str)
97  : system_error(io_errc::stream, __str) { }
98
99  ios_base::failure::failure(const string& __str, const error_code& __ec)
100  : system_error(__ec, __str) { }
101
102  ios_base::failure::failure(const char* __str, const error_code& __ec)
103  : system_error(__ec, __str) { }
104
105  ios_base::failure::~failure()
106  { }
107
108  const char*
109  ios_base::failure::what() const throw()
110  { return runtime_error::what(); }
111
112#if __cpp_rtti
113  // These functions are defined in src/c++98/ios_failure.cc
114  extern void __construct_ios_failure(void*, const char*);
115  extern void __destroy_ios_failure(void*);
116  extern bool __is_ios_failure_handler(const __cxxabiv1::__class_type_info*);
117
118  // The type thrown to report errors during stream buffer operations.
119  // In addition to the ios::failure[abi:cxx11] base class it also has a
120  // member of the gcc4-compatible ios::failure type (in an opaque buffer).
121  struct __ios_failure : std::ios::failure
122  {
123    __ios_failure(const char* s) : failure(s)
124    { __construct_ios_failure(buf, runtime_error::what()); }
125
126    __ios_failure(const char* s, const error_code& e) : failure(s, e)
127    { __construct_ios_failure(buf, runtime_error::what()); }
128
129    ~__ios_failure()
130    { __destroy_ios_failure(buf); }
131
132    // Use std::runtime_error as a proxy for the gcc4-compatible ios::failure
133    // (which can't be declared here because _GLIBCXX_USE_CXX11_ABI == 1).
134    // There are assertions in src/c++98/ios_failure.cc to ensure the size
135    // and alignment assumptions are valid.
136    alignas(runtime_error) unsigned char buf[sizeof(runtime_error)];
137  };
138
139  // Custom type info for __ios_failure.
140  class __iosfail_type_info : __cxxabiv1::__si_class_type_info
141  {
142    ~__iosfail_type_info();
143
144    bool
145    __do_upcast (const __class_type_info *dst_type,
146		 void **obj_ptr) const override;
147  };
148
149  __iosfail_type_info::~__iosfail_type_info() = default;
150
151  // This function gets called to see if an exception of type
152  // __ios_failure can be upcast to the type in a catch handler.
153  bool
154  __iosfail_type_info::__do_upcast(const __class_type_info *dst_type,
155				   void **obj_ptr) const
156  {
157    // If the handler is for the gcc4-compatible ios::failure type then
158    // catch the object stored in __ios_failure::buf instead of
159    // the __ios_failure exception object itself.
160    if (__is_ios_failure_handler(dst_type))
161      {
162	*obj_ptr = static_cast<__ios_failure*>(*obj_ptr)->buf;
163	return true;
164      }
165    // Otherwise proceed as normal to see if the handler matches.
166    return __class_type_info::__do_upcast(dst_type, obj_ptr);
167  }
168#else // ! __cpp_rtti
169  using __ios_failure = ios::failure;
170#endif
171
172  void
173  __throw_ios_failure(const char* __s __attribute__((unused)))
174  { _GLIBCXX_THROW_OR_ABORT(__ios_failure(_(__s))); }
175
176  void
177  __throw_ios_failure(const char* str __attribute__((unused)),
178		      int err __attribute__((unused)))
179  {
180    _GLIBCXX_THROW_OR_ABORT(__ios_failure(_(str),
181	  err ? error_code(err, generic_category()) : io_errc::stream));
182  }
183
184_GLIBCXX_END_NAMESPACE_VERSION
185} // namespace
186