tag-host.hpp

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
#ifndef NDN_TAG_HOST_HPP
#define NDN_TAG_HOST_HPP

#include "common.hpp"
#include "tag.hpp"

#include <map>

namespace ndn {

class TagHost
{
public:
  template<typename T>
  shared_ptr<T>
  getTag() const;

  template<typename T>
  void
  setTag(shared_ptr<T> tag) const;

  template<typename T>
  void
  removeTag() const;

private:
  mutable std::map<size_t, shared_ptr<Tag>> m_tags;
};


template<typename T>
inline shared_ptr<T>
TagHost::getTag() const
{
  static_assert(std::is_base_of<Tag, T>::value, "T must inherit from Tag");

  auto it = m_tags.find(T::getTypeId());
  if (it == m_tags.end()) {
    return nullptr;
  }
  return static_pointer_cast<T>(it->second);
}

template<typename T>
inline void
TagHost::setTag(shared_ptr<T> tag) const
{
  static_assert(std::is_base_of<Tag, T>::value, "T must inherit from Tag");

  if (tag == nullptr) {
    m_tags.erase(T::getTypeId());
    return;
  }

  m_tags[T::getTypeId()] = tag;
}

template<typename T>
inline void
TagHost::removeTag() const
{
  setTag<T>(nullptr);
}

} // namespace ndn

#endif // NDN_TAG_HOST_HPP