tag-host.hpp

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2013-2024 Regents of the University of California.
 *
 * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
 *
 * ndn-cxx library is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later version.
 *
 * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
 *
 * You should have received copies of the GNU General Public License and GNU Lesser
 * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
 * <http://www.gnu.org/licenses/>.
 *
 * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
 */
 
#ifndef NDN_CXX_DETAIL_TAG_HOST_HPP
#define NDN_CXX_DETAIL_TAG_HOST_HPP
 
#include "ndn-cxx/tag.hpp"
 
#include <map>
#include <memory>
#include <type_traits>
 
namespace ndn {
 
class TagHost
{
public:
  template<typename T>
  std::shared_ptr<T>
  getTag() const;
 
  template<typename T>
  void
  setTag(std::shared_ptr<T> tag) const;
 
  template<typename T>
  void
  removeTag() const;
 
private:
  mutable std::map<int, std::shared_ptr<Tag>> m_tags;
};
 
template<typename T>
std::shared_ptr<T>
TagHost::getTag() const
{
  static_assert(std::is_convertible_v<T*, Tag*>, "T must inherit from ndn::Tag");
 
  if (auto it = m_tags.find(T::getTypeId()); it != m_tags.end()) {
    return std::static_pointer_cast<T>(it->second);
  }
  return nullptr;
}
 
template<typename T>
void
TagHost::setTag(std::shared_ptr<T> tag) const
{
  static_assert(std::is_convertible_v<T*, Tag*>, "T must inherit from ndn::Tag");
 
  if (tag == nullptr) {
    m_tags.erase(T::getTypeId());
  }
  else {
    m_tags[T::getTypeId()] = std::move(tag);
  }
}
 
template<typename T>
void
TagHost::removeTag() const
{
  setTag<T>(nullptr);
}
 
} // namespace ndn
 
#endif // NDN_CXX_DETAIL_TAG_HOST_HPP