examples/s4u/app-bittorrent/s4u-tracker.cpp

   1 /* Copyright (c) 2012-2020. 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 <algorithm>
   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 (const std::invalid_argument&) {
  20     throw std::invalid_argument("Invalid deadline:" + args[1]);
  21   }
  22   xbt_assert(deadline > 0, "Wrong deadline supplied");
  23
  24   mailbox = simgrid::s4u::Mailbox::by_name(TRACKER_MAILBOX);
  25
  26   XBT_INFO("Tracker launched.");
  27 }
  28
  29 void Tracker::operator()()
  30 {
  31   simgrid::s4u::CommPtr comm = nullptr;
  32   void* received             = nullptr;
  33   while (simgrid::s4u::Engine::get_clock() < deadline) {
  34     if (comm == nullptr)
  35       comm = mailbox->get_async(&received);
  36     if (comm->test()) {
  37       // Retrieve the data sent by the peer.
  38       xbt_assert(received != nullptr);
  39       TrackerQuery* tq = static_cast<TrackerQuery*>(received);
  40
  41       // Add the peer to our peer list, if not already known.
  42       if (known_peers.find(tq->getPeerId()) == known_peers.end()) {
  43         known_peers.insert(tq->getPeerId());
  44       }
  45
  46       // Sending back peers to the requesting peer
  47       TrackerAnswer* ta = new TrackerAnswer(TRACKER_QUERY_INTERVAL);
  48       std::set<int>::iterator next_peer;
  49       int nb_known_peers = static_cast<int>(known_peers.size());
  50       int max_tries      = std::min(MAXIMUM_PEERS, nb_known_peers);
  51       int tried          = 0;
  52       while (tried < max_tries) {
  53         do {
  54           next_peer = known_peers.begin();
  55           std::advance(next_peer, random.uniform_int(0, nb_known_peers - 1));
  56         } while (ta->getPeers().find(*next_peer) != ta->getPeers().end());
  57         ta->addPeer(*next_peer);
  58         tried++;
  59       }
  60       tq->getReturnMailbox()->put_init(ta, TRACKER_COMM_SIZE)->detach();
  61
  62       delete tq;
  63       comm = nullptr;
  64     } else {
  65       simgrid::s4u::this_actor::sleep_for(1);
  66     }
  67   }
  68   XBT_INFO("Tracker is leaving");
  69 }