consumer.hpp

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2014-2020,  The University of Memphis
 *
 * This file is part of PSync.
 * See AUTHORS.md for complete list of PSync authors and contributors.
 *
 * PSync 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.
 *
 * PSync 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 a copy of the GNU Lesser General Public License along with
 * PSync, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef PSYNC_CONSUMER_HPP
#define PSYNC_CONSUMER_HPP

#include "PSync/common.hpp"
#include "PSync/detail/access-specifiers.hpp"
#include "PSync/detail/bloom-filter.hpp"

#include <ndn-cxx/face.hpp>
#include <ndn-cxx/util/random.hpp>
#include <ndn-cxx/util/scheduler.hpp>
#include <ndn-cxx/util/segment-fetcher.hpp>
#include <ndn-cxx/util/time.hpp>

#include <map>

namespace psync {

using namespace ndn::time_literals;

using ReceiveHelloCallback = std::function<void(const std::map<ndn::Name, uint64_t>&)>;

const ndn::time::milliseconds HELLO_INTEREST_LIFETIME = 1_s;
const ndn::time::milliseconds SYNC_INTEREST_LIFETIME = 1_s;

class Consumer
{
public:
  Consumer(const ndn::Name& syncPrefix,
           ndn::Face& face,
           const ReceiveHelloCallback& onReceiveHelloData,
           const UpdateCallback& onUpdate,
           unsigned int count,
           double false_positive,
           ndn::time::milliseconds helloInterestLifetime = HELLO_INTEREST_LIFETIME,
           ndn::time::milliseconds syncInterestLifetime = SYNC_INTEREST_LIFETIME);

  void
  sendHelloInterest();

  void
  sendSyncInterest();

  bool
  addSubscription(const ndn::Name& prefix, uint64_t seqNo, bool callSyncDataCb = true);

  std::set<ndn::Name>
  getSubscriptionList() const
  {
    return m_subscriptionList;
  }

  bool
  isSubscribed(const ndn::Name& prefix) const
  {
    return m_subscriptionList.find(prefix) != m_subscriptionList.end();
  }

  ndn::optional<uint64_t>
  getSeqNo(const ndn::Name& prefix) const
  {
    auto it = m_prefixes.find(prefix);
    if (it == m_prefixes.end()) {
      return ndn::nullopt;
    }
    return it->second;
  }

  void
  stop();

private:
  void
  onHelloData(const ndn::ConstBufferPtr& bufferPtr);

  void
  onSyncData(const ndn::ConstBufferPtr& bufferPtr);

PSYNC_PUBLIC_WITH_TESTS_ELSE_PRIVATE:
  ndn::Face& m_face;
  ndn::Scheduler m_scheduler;

  ndn::Name m_syncPrefix;
  ndn::Name m_helloInterestPrefix;
  ndn::Name m_syncInterestPrefix;
  ndn::Name m_iblt;
  ndn::Name m_helloDataName;
  ndn::Name m_syncDataName;
  uint32_t m_syncDataContentType;

  ReceiveHelloCallback m_onReceiveHelloData;

  // Called when new sync update is received from producer.
  UpdateCallback m_onUpdate;

  // Bloom filter is used to store application/user's subscription list.
  detail::BloomFilter m_bloomFilter;

  ndn::time::milliseconds m_helloInterestLifetime;
  ndn::time::milliseconds m_syncInterestLifetime;

  // Store sequence number for the prefix.
  std::map<ndn::Name, uint64_t> m_prefixes;
  std::set<ndn::Name> m_subscriptionList;

  ndn::random::RandomNumberEngine& m_rng;
  std::uniform_int_distribution<> m_rangeUniformRandom;
  std::shared_ptr<ndn::util::SegmentFetcher> m_helloFetcher;
  std::shared_ptr<ndn::util::SegmentFetcher> m_syncFetcher;
};

} // namespace psync

#endif // PSYNC_CONSUMER_HPP