libcxx/include/system_error

// -*- C++ -*-
//===---------------------------- system_error ----------------------------===//
//
// 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
#define _LIBCPP_SYSTEM_ERROR

/*
    system_error synopsis

namespace std
{

class error_category
{
public:
    virtual ~error_category() noexcept;

    constexpr error_category();
    error_category(const error_category&) = delete;
    error_category& operator=(const error_category&) = delete;

    virtual const char* name() const noexcept = 0;
    virtual error_condition default_error_condition(int ev) const noexcept;
    virtual bool equivalent(int code, const error_condition& condition) const noexcept;
    virtual bool equivalent(const error_code& code, int condition) const noexcept;
    virtual string message(int ev) const = 0;

    bool operator==(const error_category& rhs) const noexcept;
    bool operator!=(const error_category& rhs) const noexcept;
    bool operator<(const error_category& rhs) const noexcept;
};

const error_category& generic_category() noexcept;
const error_category& system_category() noexcept;

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

template <class T> struct is_error_condition_enum
    : public false_type {};

template <class _Tp>
inline constexpr size_t is_error_condition_enum_v = is_error_condition_enum<_Tp>::value; // C++17

template <class _Tp>
inline constexpr size_t is_error_code_enum_v = is_error_code_enum<_Tp>::value; // C++17

class error_code
{
public:
    // constructors:
    error_code() noexcept;
    error_code(int val, const error_category& cat) noexcept;
    template <class ErrorCodeEnum>
        error_code(ErrorCodeEnum e) noexcept;

    // modifiers:
    void assign(int val, const error_category& cat) noexcept;
    template <class ErrorCodeEnum>
        error_code& operator=(ErrorCodeEnum e) noexcept;
    void clear() noexcept;

    // observers:
    int value() const noexcept;
    const error_category& category() const noexcept;
    error_condition default_error_condition() const noexcept;
    string message() const;
    explicit operator bool() const noexcept;
};

// non-member functions:
bool operator<(const error_code& lhs, const error_code& rhs) noexcept;
template <class charT, class traits>
    basic_ostream<charT,traits>&
    operator<<(basic_ostream<charT,traits>& os, const error_code& ec);

class error_condition
{
public:
    // constructors:
    error_condition() noexcept;
    error_condition(int val, const error_category& cat) noexcept;
    template <class ErrorConditionEnum>
        error_condition(ErrorConditionEnum e) noexcept;

    // modifiers:
    void assign(int val, const error_category& cat) noexcept;
    template <class ErrorConditionEnum>
        error_condition& operator=(ErrorConditionEnum e) noexcept;
    void clear() noexcept;

    // observers:
    int value() const noexcept;
    const error_category& category() const noexcept;
    string message() const noexcept;
    explicit operator bool() const noexcept;
};

bool operator<(const error_condition& lhs, const error_condition& rhs) noexcept;

class system_error
    : public runtime_error
{
public:
    system_error(error_code ec, const string& what_arg);
    system_error(error_code ec, const char* what_arg);
    system_error(error_code ec);
    system_error(int ev, const error_category& ecat, const string& what_arg);
    system_error(int ev, const error_category& ecat, const char* what_arg);
    system_error(int ev, const error_category& ecat);

    const error_code& code() const noexcept;
    const char* what() const noexcept;
};

template <> struct is_error_condition_enum<errc>
    : true_type { }

error_code make_error_code(errc e) noexcept;
error_condition make_error_condition(errc e) noexcept;

// Comparison operators:
bool operator==(const error_code& lhs, const error_code& rhs) noexcept;
bool operator==(const error_code& lhs, const error_condition& rhs) noexcept;
bool operator==(const error_condition& lhs, const error_code& rhs) noexcept;
bool operator==(const error_condition& lhs, const error_condition& rhs) noexcept;
bool operator!=(const error_code& lhs, const error_code& rhs) noexcept;
bool operator!=(const error_code& lhs, const error_condition& rhs) noexcept;
bool operator!=(const error_condition& lhs, const error_code& rhs) noexcept;
bool operator!=(const error_condition& lhs, const error_condition& rhs) noexcept;

template <> struct hash<std::error_code>;
template <> struct hash<std::error_condition>;

}  // std

*/

#include <__errc>
#include <type_traits>
#include <stdexcept>
#include <__functional_base>
#include <string>

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

_LIBCPP_BEGIN_NAMESPACE_STD

// is_error_code_enum

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

#if _LIBCPP_STD_VER > 14
template <class _Tp>
_LIBCPP_INLINE_VAR constexpr size_t is_error_code_enum_v = is_error_code_enum<_Tp>::value;
#endif

// is_error_condition_enum

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

#if _LIBCPP_STD_VER > 14
template <class _Tp>
_LIBCPP_INLINE_VAR constexpr size_t is_error_condition_enum_v = is_error_condition_enum<_Tp>::value;
#endif

template <>
struct _LIBCPP_TEMPLATE_VIS is_error_condition_enum<errc>
    : true_type { };

#ifdef _LIBCPP_HAS_NO_STRONG_ENUMS
template <>
struct _LIBCPP_TEMPLATE_VIS is_error_condition_enum<errc::__lx>
    : true_type { };
#endif

class _LIBCPP_TYPE_VIS error_condition;
class _LIBCPP_TYPE_VIS error_code;

// class error_category

class _LIBCPP_HIDDEN __do_message;

class _LIBCPP_TYPE_VIS error_category
{
public:
    virtual ~error_category() _NOEXCEPT;

#if defined(_LIBCPP_BUILDING_LIBRARY) && \
    defined(_LIBCPP_DEPRECATED_ABI_LEGACY_LIBRARY_DEFINITIONS_FOR_INLINE_FUNCTIONS)
    error_category() _NOEXCEPT;
#else
    _LIBCPP_INLINE_VISIBILITY
    _LIBCPP_CONSTEXPR_AFTER_CXX11 error_category() _NOEXCEPT _LIBCPP_DEFAULT
#endif
private:
    error_category(const error_category&);// = delete;
    error_category& operator=(const error_category&);// = delete;

public:
    virtual const char* name() const _NOEXCEPT = 0;
    virtual error_condition default_error_condition(int __ev) const _NOEXCEPT;
    virtual bool equivalent(int __code, const error_condition& __condition) const _NOEXCEPT;
    virtual bool equivalent(const error_code& __code, int __condition) const _NOEXCEPT;
    virtual string message(int __ev) const = 0;

    _LIBCPP_INLINE_VISIBILITY
    bool operator==(const error_category& __rhs) const _NOEXCEPT {return this == &__rhs;}

    _LIBCPP_INLINE_VISIBILITY
    bool operator!=(const error_category& __rhs) const _NOEXCEPT {return !(*this == __rhs);}

    _LIBCPP_INLINE_VISIBILITY
    bool operator< (const error_category& __rhs) const _NOEXCEPT {return this < &__rhs;}

    friend class _LIBCPP_HIDDEN __do_message;
};

class _LIBCPP_HIDDEN __do_message
    : public error_category
{
public:
    virtual string message(int ev) const;
};

_LIBCPP_FUNC_VIS const error_category& generic_category() _NOEXCEPT;
_LIBCPP_FUNC_VIS const error_category& system_category() _NOEXCEPT;

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

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

    template <class _Ep>
        _LIBCPP_INLINE_VISIBILITY
        error_condition(_Ep __e,
              typename enable_if<is_error_condition_enum<_Ep>::value>::type* = 0
                                                                     ) _NOEXCEPT
            {*this = make_error_condition(__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_condition_enum<_Ep>::value,
            error_condition&
        >::type
        operator=(_Ep __e) _NOEXCEPT
            {*this = make_error_condition(__e); return *this;}

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

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

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

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

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

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

// error_code

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* = 0
                                                                     ) _NOEXCEPT
            {*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
            {*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
        _LIBCPP_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.category() == __y.category() && __x.value() < __y.value());
}

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());
}

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

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

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_condition& __x, const error_condition& __y) _NOEXCEPT
{return !(__x == __y);}

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());
    }
};

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

// system_error

class _LIBCPP_TYPE_VIS system_error
    : public runtime_error
{
    error_code __ec_;
public:
    system_error(error_code __ec, const string& __what_arg);
    system_error(error_code __ec, const char* __what_arg);
    system_error(error_code __ec);
    system_error(int __ev, const error_category& __ecat, const string& __what_arg);
    system_error(int __ev, const error_category& __ecat, const char* __what_arg);
    system_error(int __ev, const error_category& __ecat);
    ~system_error() _NOEXCEPT;

    _LIBCPP_INLINE_VISIBILITY
    const error_code& code() const _NOEXCEPT {return __ec_;}

private:
    static string __init(const error_code&, string);
};

_LIBCPP_NORETURN _LIBCPP_FUNC_VIS
void __throw_system_error(int ev, const char* what_arg);

_LIBCPP_END_NAMESPACE_STD

#endif  // _LIBCPP_SYSTEM_ERROR