examples/s4u/app-bittorrent/s4u_tracker.cpp

   1 /* Copyright (c) 2012-2017. The SimGrid Team.
   2  * All rights reserved.                                                     */
   3
   4 /* This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the license (GNU LGPL) which comes with this package. */
   6
   7 #include "s4u_tracker.hpp"
   8 #include <xbt/RngStream.h>
   9
  10 XBT_LOG_NEW_DEFAULT_CATEGORY(s4u_bt_tracker, "Messages specific for the tracker");
  11
  12 Tracker::Tracker(std::vector<std::string> args)
  13 {
  14   // Checking arguments
  15   xbt_assert(args.size() == 2, "Wrong number of arguments for the tracker.");
  16   // Retrieving end time
  17   try {
  18     deadline = std::stod(args[1]);
  19   } catch (std::invalid_argument& ia) {
  20     throw std::invalid_argument(std::string("Invalid deadline:") + args[1].c_str());
  21   }
  22   xbt_assert(deadline > 0, "Wrong deadline supplied");
  23
  24   stream = simgrid::s4u::this_actor::getHost()->extension<HostBittorrent>()->getStream();
  25
  26   mailbox = simgrid::s4u::Mailbox::byName(TRACKER_MAILBOX);
  27
  28   XBT_INFO("Tracker launched.");
  29 }
  30
  31 void Tracker::operator()()
  32 {
  33   simgrid::s4u::CommPtr comm = nullptr;
  34   while (simgrid::s4u::Engine::getClock() < deadline) {
  35     void* received;
  36     if (comm == nullptr)
  37       comm = mailbox->get_async(&received);
  38     if (comm->test()) {
  39       // Retrieve the data sent by the peer.
  40       TrackerQuery* tq = static_cast<TrackerQuery*>(received);
  41
  42       // Add the peer to our peer list, if not already known.
  43       if (known_peers.find(tq->getPeerId()) == known_peers.end()) {
  44         known_peers.insert(tq->getPeerId());
  45       }
  46
  47       // Sending back peers to the requesting peer
  48       TrackerAnswer* ta = new TrackerAnswer(TRACKER_QUERY_INTERVAL);
  49       std::set<int>::iterator next_peer;
  50       int nb_known_peers = known_peers.size();
  51       int max_tries      = MIN(MAXIMUM_PEERS, nb_known_peers);
  52       int tried          = 0;
  53       while (tried < max_tries) {
  54         do {
  55           next_peer = known_peers.begin();
  56           std::advance(next_peer, RngStream_RandInt(stream, 0, nb_known_peers - 1));
  57         } while (ta->getPeers()->find(*next_peer) != ta->getPeers()->end());
  58         ta->addPeer(*next_peer);
  59         tried++;
  60       }
  61       tq->getReturnMailbox()->put_init(ta, TRACKER_COMM_SIZE)->detach();
  62
  63       delete tq;
  64       comm = nullptr;
  65     } else {
  66       simgrid::s4u::this_actor::sleep_for(1);
  67     }
  68   }
  69   XBT_INFO("Tracker is leaving");
  70 }