chromium/base/types/token_type.h

// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef BASE_TYPES_TOKEN_TYPE_H_
#define BASE_TYPES_TOKEN_TYPE_H_

#include <compare>
#include <type_traits>

#include "base/check.h"
#include "base/types/strong_alias.h"
#include "base/unguessable_token.h"

namespace base {

// A specialization of StrongAlias for UnguessableToken. Unlike
// UnguessableToken, a TokenType<...> does not default to null and does not
// expose the concept of null tokens. If you need to indicate a null token,
// please use std::optional<TokenType<...>>.
template <typename TypeMarker>
class TokenType : public StrongAlias<TypeMarker, UnguessableToken> { … };

}  // namespace base

#endif  // BASE_TYPES_TOKEN_TYPE_H_