libcxx/include/__system_error/error_code.h

   1 // -*- C++ -*-
   2 //===----------------------------------------------------------------------===//
   3 //
   4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   5 // See https://llvm.org/LICENSE.txt for license information.
   6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #ifndef _LIBCPP___SYSTEM_ERROR_ERROR_CODE_H
  11 #define _LIBCPP___SYSTEM_ERROR_ERROR_CODE_H
  12
  13 #include <__compare/ordering.h>
  14 #include <__config>
  15 #include <__functional/hash.h>
  16 #include <__functional/unary_function.h>
  17 #include <__system_error/errc.h>
  18 #include <__system_error/error_category.h>
  19 #include <__system_error/error_condition.h>
  20 #include <string>
  21
  22 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  23 #  pragma GCC system_header
  24 #endif
  25
  26 _LIBCPP_BEGIN_NAMESPACE_STD
  27
  28 template <class _Tp>
  29 struct _LIBCPP_TEMPLATE_VIS is_error_code_enum : public false_type {};
  30
  31 #if _LIBCPP_STD_VER >= 17
  32 template <class _Tp>
  33 inline constexpr bool is_error_code_enum_v = is_error_code_enum<_Tp>::value;
  34 #endif
  35
  36 namespace __adl_only {
  37 // Those cause ADL to trigger but they are not viable candidates,
  38 // so they are never actually selected.
  39 void make_error_code() = delete;
  40 } // namespace __adl_only
  41
  42 class _LIBCPP_EXPORTED_FROM_ABI error_code {
  43   int __val_;
  44   const error_category* __cat_;
  45
  46 public:
  47   _LIBCPP_HIDE_FROM_ABI error_code() _NOEXCEPT : __val_(0), __cat_(&system_category()) {}
  48
  49   _LIBCPP_HIDE_FROM_ABI error_code(int __val, const error_category& __cat) _NOEXCEPT : __val_(__val), __cat_(&__cat) {}
  50
  51   template <class _Ep, __enable_if_t<is_error_code_enum<_Ep>::value, int> = 0>
  52   _LIBCPP_HIDE_FROM_ABI error_code(_Ep __e) _NOEXCEPT {
  53     using __adl_only::make_error_code;
  54     *this = make_error_code(__e);
  55   }
  56
  57   _LIBCPP_HIDE_FROM_ABI void assign(int __val, const error_category& __cat) _NOEXCEPT {
  58     __val_ = __val;
  59     __cat_ = &__cat;
  60   }
  61
  62   template <class _Ep, __enable_if_t<is_error_code_enum<_Ep>::value, int> = 0>
  63   _LIBCPP_HIDE_FROM_ABI error_code& operator=(_Ep __e) _NOEXCEPT {
  64     using __adl_only::make_error_code;
  65     *this = make_error_code(__e);
  66     return *this;
  67   }
  68
  69   _LIBCPP_HIDE_FROM_ABI void clear() _NOEXCEPT {
  70     __val_ = 0;
  71     __cat_ = &system_category();
  72   }
  73
  74   _LIBCPP_HIDE_FROM_ABI int value() const _NOEXCEPT { return __val_; }
  75
  76   _LIBCPP_HIDE_FROM_ABI const error_category& category() const _NOEXCEPT { return *__cat_; }
  77
  78   _LIBCPP_HIDE_FROM_ABI error_condition default_error_condition() const _NOEXCEPT {
  79     return __cat_->default_error_condition(__val_);
  80   }
  81
  82   string message() const;
  83
  84   _LIBCPP_HIDE_FROM_ABI explicit operator bool() const _NOEXCEPT { return __val_ != 0; }
  85 };
  86
  87 inline _LIBCPP_HIDE_FROM_ABI error_code make_error_code(errc __e) _NOEXCEPT {
  88   return error_code(static_cast<int>(__e), generic_category());
  89 }
  90
  91 inline _LIBCPP_HIDE_FROM_ABI bool operator==(const error_code& __x, const error_code& __y) _NOEXCEPT {
  92   return __x.category() == __y.category() && __x.value() == __y.value();
  93 }
  94
  95 inline _LIBCPP_HIDE_FROM_ABI bool operator==(const error_code& __x, const error_condition& __y) _NOEXCEPT {
  96   return __x.category().equivalent(__x.value(), __y) || __y.category().equivalent(__x, __y.value());
  97 }
  98
  99 #if _LIBCPP_STD_VER <= 17
 100 inline _LIBCPP_HIDE_FROM_ABI bool operator==(const error_condition& __x, const error_code& __y) _NOEXCEPT {
 101   return __y == __x;
 102 }
 103 #endif
 104
 105 #if _LIBCPP_STD_VER <= 17
 106
 107 inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const error_code& __x, const error_code& __y) _NOEXCEPT {
 108   return !(__x == __y);
 109 }
 110
 111 inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const error_code& __x, const error_condition& __y) _NOEXCEPT {
 112   return !(__x == __y);
 113 }
 114
 115 inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const error_condition& __x, const error_code& __y) _NOEXCEPT {
 116   return !(__x == __y);
 117 }
 118
 119 inline _LIBCPP_HIDE_FROM_ABI bool operator<(const error_code& __x, const error_code& __y) _NOEXCEPT {
 120   return __x.category() < __y.category() || (__x.category() == __y.category() && __x.value() < __y.value());
 121 }
 122
 123 #else // _LIBCPP_STD_VER <= 17
 124
 125 inline _LIBCPP_HIDE_FROM_ABI strong_ordering operator<=>(const error_code& __x, const error_code& __y) noexcept {
 126   if (auto __c = __x.category() <=> __y.category(); __c != 0)
 127     return __c;
 128   return __x.value() <=> __y.value();
 129 }
 130
 131 #endif // _LIBCPP_STD_VER <= 17
 132
 133 template <>
 134 struct _LIBCPP_TEMPLATE_VIS hash<error_code> : public __unary_function<error_code, size_t> {
 135   _LIBCPP_HIDE_FROM_ABI size_t operator()(const error_code& __ec) const _NOEXCEPT {
 136     return static_cast<size_t>(__ec.value());
 137   }
 138 };
 139
 140 _LIBCPP_END_NAMESPACE_STD
 141
 142 #endif // _LIBCPP___SYSTEM_ERROR_ERROR_CODE_H