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

   1 /* Copyright (c) 2012-2018. 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 #include <xbt/RngStream.h>
  10
  11 XBT_LOG_NEW_DEFAULT_CATEGORY(s4u_bt_tracker, "Messages specific for the tracker");
  12
  13 Tracker::Tracker(std::vector<std::string> args)
  14 {
  15   // Checking arguments
  16   xbt_assert(args.size() == 2, "Wrong number of arguments for the tracker.");
  17   // Retrieving end time
  18   try {
  19     deadline = std::stod(args[1]);
  20   } catch (std::invalid_argument& ia) {
  21     throw std::invalid_argument(std::string("Invalid deadline:") + args[1].c_str());
  22   }
  23   xbt_assert(deadline > 0, "Wrong deadline supplied");
  24
  25   stream = simgrid::s4u::this_actor::get_host()->extension<HostBittorrent>()->getStream();
  26
  27   mailbox = simgrid::s4u::Mailbox::byName(TRACKER_MAILBOX);
  28
  29   XBT_INFO("Tracker launched.");
  30 }
  31
  32 void Tracker::operator()()
  33 {
  34   simgrid::s4u::CommPtr comm = nullptr;
  35   void* received             = nullptr;
  36   while (simgrid::s4u::Engine::get_clock() < deadline) {
  37     if (comm == nullptr)
  38       comm = mailbox->get_async(&received);
  39     if (comm->test()) {
  40       // Retrieve the data sent by the peer.
  41       xbt_assert(received != nullptr);
  42       TrackerQuery* tq = static_cast<TrackerQuery*>(received);
  43
  44       // Add the peer to our peer list, if not already known.
  45       if (known_peers.find(tq->getPeerId()) == known_peers.end()) {
  46         known_peers.insert(tq->getPeerId());
  47       }
  48
  49       // Sending back peers to the requesting peer
  50       TrackerAnswer* ta = new TrackerAnswer(TRACKER_QUERY_INTERVAL);
  51       std::set<int>::iterator next_peer;
  52       int nb_known_peers = known_peers.size();
  53       int max_tries      = std::min(MAXIMUM_PEERS, nb_known_peers);
  54       int tried          = 0;
  55       while (tried < max_tries) {
  56         do {
  57           next_peer = known_peers.begin();
  58           std::advance(next_peer, RngStream_RandInt(stream, 0, nb_known_peers - 1));
  59         } while (ta->getPeers()->find(*next_peer) != ta->getPeers()->end());
  60         ta->addPeer(*next_peer);
  61         tried++;
  62       }
  63       tq->getReturnMailbox()->put_init(ta, TRACKER_COMM_SIZE)->detach();
  64
  65       delete tq;
  66       comm = nullptr;
  67     } else {
  68       simgrid::s4u::this_actor::sleep_for(1);
  69     }
  70   }
  71   XBT_INFO("Tracker is leaving");
  72 }