clang-p2996/libcxx/include/__system_error/error_code.h

// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP___SYSTEM_ERROR_ERROR_CODE_H
#define _LIBCPP___SYSTEM_ERROR_ERROR_CODE_H

#include <__compare/ordering.h>
#include <__config>
#include <__functional/hash.h>
#include <__functional/unary_function.h>
#include <__system_error/errc.h>
#include <__system_error/error_category.h>
#include <__system_error/error_condition.h>
#include <cstddef>
#include <string>

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#  pragma GCC system_header
#endif

_LIBCPP_BEGIN_NAMESPACE_STD

template <class _Tp>
struct _LIBCPP_TEMPLATE_VIS is_error_code_enum
    : public false_type {};

#if _LIBCPP_STD_VER >= 17
template <class _Tp>
inline constexpr bool is_error_code_enum_v = is_error_code_enum<_Tp>::value;
#endif

namespace __adl_only {
    // Those cause ADL to trigger but they are not viable candidates,
    // so they are never actually selected.
    void make_error_code() = delete;
} // namespace __adl_only

class _LIBCPP_TYPE_VIS error_code
{
    int __val_;
    const error_category* __cat_;
public:
    _LIBCPP_INLINE_VISIBILITY
    error_code() _NOEXCEPT : __val_(0), __cat_(&system_category()) {}

    _LIBCPP_INLINE_VISIBILITY
    error_code(int __val, const error_category& __cat) _NOEXCEPT
        : __val_(__val), __cat_(&__cat) {}

    template <class _Ep>
        _LIBCPP_INLINE_VISIBILITY
        error_code(_Ep __e,
                   typename enable_if<is_error_code_enum<_Ep>::value>::type* = nullptr
                                                                     ) _NOEXCEPT
            {
                using __adl_only::make_error_code;
                *this = make_error_code(__e);
            }

    _LIBCPP_INLINE_VISIBILITY
    void assign(int __val, const error_category& __cat) _NOEXCEPT
    {
        __val_ = __val;
        __cat_ = &__cat;
    }

    template <class _Ep>
        _LIBCPP_INLINE_VISIBILITY
        typename enable_if
        <
            is_error_code_enum<_Ep>::value,
            error_code&
        >::type
        operator=(_Ep __e) _NOEXCEPT
            {
                using __adl_only::make_error_code;
                *this = make_error_code(__e);
                return *this;
            }

    _LIBCPP_INLINE_VISIBILITY
    void clear() _NOEXCEPT
    {
        __val_ = 0;
        __cat_ = &system_category();
    }

    _LIBCPP_INLINE_VISIBILITY
    int value() const _NOEXCEPT {return __val_;}

    _LIBCPP_INLINE_VISIBILITY
    const error_category& category() const _NOEXCEPT {return *__cat_;}

    _LIBCPP_INLINE_VISIBILITY
    error_condition default_error_condition() const _NOEXCEPT
        {return __cat_->default_error_condition(__val_);}

    string message() const;

    _LIBCPP_INLINE_VISIBILITY
    explicit operator bool() const _NOEXCEPT {return __val_ != 0;}
};

inline _LIBCPP_INLINE_VISIBILITY
error_code
make_error_code(errc __e) _NOEXCEPT
{
    return error_code(static_cast<int>(__e), generic_category());
}

inline _LIBCPP_INLINE_VISIBILITY
bool
operator==(const error_code& __x, const error_code& __y) _NOEXCEPT
{
    return __x.category() == __y.category() && __x.value() == __y.value();
}

inline _LIBCPP_INLINE_VISIBILITY
bool
operator==(const error_code& __x, const error_condition& __y) _NOEXCEPT
{
    return __x.category().equivalent(__x.value(), __y)
        || __y.category().equivalent(__x, __y.value());
}

#if _LIBCPP_STD_VER <= 17
inline _LIBCPP_INLINE_VISIBILITY
bool
operator==(const error_condition& __x, const error_code& __y) _NOEXCEPT
{
    return __y == __x;
}
#endif

#if _LIBCPP_STD_VER <= 17

inline _LIBCPP_INLINE_VISIBILITY
bool
operator!=(const error_code& __x, const error_code& __y) _NOEXCEPT
{return !(__x == __y);}

inline _LIBCPP_INLINE_VISIBILITY
bool
operator!=(const error_code& __x, const error_condition& __y) _NOEXCEPT
{return !(__x == __y);}

inline _LIBCPP_INLINE_VISIBILITY
bool
operator!=(const error_condition& __x, const error_code& __y) _NOEXCEPT
{return !(__x == __y);}

inline _LIBCPP_INLINE_VISIBILITY
bool
operator<(const error_code& __x, const error_code& __y) _NOEXCEPT
{
    return __x.category() < __y.category()
        || (__x.category() == __y.category() && __x.value() < __y.value());
}

#else // _LIBCPP_STD_VER <= 17

inline _LIBCPP_HIDE_FROM_ABI strong_ordering
operator<=>(const error_code& __x, const error_code& __y) noexcept
{
    if (auto __c = __x.category() <=> __y.category(); __c != 0)
        return __c;
    return __x.value() <=> __y.value();
}

#endif // _LIBCPP_STD_VER <= 17

template <>
struct _LIBCPP_TEMPLATE_VIS hash<error_code>
    : public __unary_function<error_code, size_t>
{
    _LIBCPP_INLINE_VISIBILITY
    size_t operator()(const error_code& __ec) const _NOEXCEPT
    {
        return static_cast<size_t>(__ec.value());
    }
};

_LIBCPP_END_NAMESPACE_STD

#endif // _LIBCPP___SYSTEM_ERROR_ERROR_CODE_H