pending-interest.hpp

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2013-2021 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_IMPL_PENDING_INTEREST_HPP
#define NDN_CXX_IMPL_PENDING_INTEREST_HPP

#include "ndn-cxx/data.hpp"
#include "ndn-cxx/face.hpp"
#include "ndn-cxx/interest.hpp"
#include "ndn-cxx/impl/record-container.hpp"
#include "ndn-cxx/lp/nack.hpp"
#include "ndn-cxx/util/scheduler.hpp"

namespace ndn {

enum class PendingInterestOrigin
{
  APP, 
  FORWARDER 
};

std::ostream&
operator<<(std::ostream& os, PendingInterestOrigin origin)
{
  switch (origin) {
    case PendingInterestOrigin::APP:
      return os << "app";
    case PendingInterestOrigin::FORWARDER:
      return os << "forwarder";
  }
  NDN_CXX_UNREACHABLE;
}

class PendingInterest : public detail::RecordBase<PendingInterest>
{
public:
  PendingInterest(shared_ptr<const Interest> interest, const DataCallback& dataCallback,
                  const NackCallback& nackCallback, const TimeoutCallback& timeoutCallback,
                  Scheduler& scheduler)
    : m_interest(std::move(interest))
    , m_origin(PendingInterestOrigin::APP)
    , m_dataCallback(dataCallback)
    , m_nackCallback(nackCallback)
    , m_timeoutCallback(timeoutCallback)
  {
    scheduleTimeoutEvent(scheduler);
  }

  PendingInterest(shared_ptr<const Interest> interest, Scheduler& scheduler)
    : m_interest(std::move(interest))
    , m_origin(PendingInterestOrigin::FORWARDER)
  {
    scheduleTimeoutEvent(scheduler);
  }

  shared_ptr<const Interest>
  getInterest() const
  {
    return m_interest;
  }

  PendingInterestOrigin
  getOrigin() const
  {
    return m_origin;
  }

  void
  recordForwarding()
  {
    ++m_nNotNacked;
  }

  optional<lp::Nack>
  recordNack(const lp::Nack& nack)
  {
    --m_nNotNacked;
    BOOST_ASSERT(m_nNotNacked >= 0);

    if (!m_leastSevereNack || lp::isLessSevere(nack.getReason(), m_leastSevereNack->getReason())) {
      m_leastSevereNack = nack;
    }

    return m_nNotNacked > 0 ? nullopt : m_leastSevereNack;
  }

  void
  invokeDataCallback(const Data& data)
  {
    if (m_dataCallback) {
      m_dataCallback(*m_interest, data);
    }
  }

  void
  invokeNackCallback(const lp::Nack& nack)
  {
    if (m_nackCallback) {
      m_nackCallback(*m_interest, nack);
    }
  }

private:
  void
  scheduleTimeoutEvent(Scheduler& scheduler)
  {
    m_timeoutEvent = scheduler.schedule(m_interest->getInterestLifetime(),
                                        [=] { this->invokeTimeoutCallback(); });
  }

  void
  invokeTimeoutCallback()
  {
    if (m_timeoutCallback) {
      m_timeoutCallback(*m_interest);
    }

    deleteSelf();
  }

private:
  shared_ptr<const Interest> m_interest;
  PendingInterestOrigin m_origin;
  DataCallback m_dataCallback;
  NackCallback m_nackCallback;
  TimeoutCallback m_timeoutCallback;
  scheduler::ScopedEventId m_timeoutEvent;
  int m_nNotNacked = 0; 
  optional<lp::Nack> m_leastSevereNack;
};

} // namespace ndn

#endif // NDN_CXX_IMPL_PENDING_INTEREST_HPP