include/__chrono/time_zone_link.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
//
//===----------------------------------------------------------------------===//

// For information see https://libcxx.llvm.org/DesignDocs/TimeZone.html

#ifndef _LIBCPP___CHRONO_TIME_ZONE_LINK_H
#define _LIBCPP___CHRONO_TIME_ZONE_LINK_H

#include <version>
// Enable the contents of the header only when libc++ was built with experimental features enabled.
#if !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_TZDB)

#  include <__compare/strong_order.h>
#  include <__config>
#  include <__utility/private_constructor_tag.h>
#  include <string>
#  include <string_view>

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

_LIBCPP_PUSH_MACROS
#  include <__undef_macros>

_LIBCPP_BEGIN_NAMESPACE_STD

#  if _LIBCPP_STD_VER >= 20 && _LIBCPP_HAS_TIME_ZONE_DATABASE && _LIBCPP_HAS_FILESYSTEM && _LIBCPP_HAS_LOCALIZATION

namespace chrono {

class time_zone_link {
public:
  [[nodiscard]]
  _LIBCPP_HIDE_FROM_ABI explicit time_zone_link(__private_constructor_tag, string_view __name, string_view __target)
      : __name_{__name}, __target_{__target} {}

  _LIBCPP_HIDE_FROM_ABI time_zone_link(time_zone_link&&)            = default;
  _LIBCPP_HIDE_FROM_ABI time_zone_link& operator=(time_zone_link&&) = default;

  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI string_view name() const noexcept { return __name_; }
  [[nodiscard]] _LIBCPP_HIDE_FROM_ABI string_view target() const noexcept { return __target_; }

private:
  string __name_;
  // TODO TZDB instead of the name we can store the pointer to a zone. These
  // pointers are immutable. This makes it possible to directly return a
  // pointer in the time_zone in the 'locate_zone' function.
  string __target_;
};

[[nodiscard]] _LIBCPP_AVAILABILITY_TZDB _LIBCPP_HIDE_FROM_ABI inline bool
operator==(const time_zone_link& __x, const time_zone_link& __y) noexcept {
  return __x.name() == __y.name();
}

[[nodiscard]] _LIBCPP_AVAILABILITY_TZDB _LIBCPP_HIDE_FROM_ABI inline strong_ordering
operator<=>(const time_zone_link& __x, const time_zone_link& __y) noexcept {
  return __x.name() <=> __y.name();
}

} // namespace chrono

#  endif // _LIBCPP_STD_VER >= 20 && _LIBCPP_HAS_TIME_ZONE_DATABASE && _LIBCPP_HAS_FILESYSTEM &&
         // _LIBCPP_HAS_LOCALIZATION

_LIBCPP_END_NAMESPACE_STD

_LIBCPP_POP_MACROS

#endif // !defined(_LIBCPP_HAS_NO_EXPERIMENTAL_TZDB)

#endif // _LIBCPP___CHRONO_TIME_ZONE_LINK_H