src/lib/server_finder.cc

   1 /*
   2     Copyright (C) 2013 Carl Hetherington <cth@carlh.net>
   3
   4     This program is free software; you can redistribute it and/or modify
   5     it under the terms of the GNU General Public License as published by
   6     the Free Software Foundation; either version 2 of the License, or
   7     (at your option) any later version.
   8
   9     This program is distributed in the hope that it will be useful,
  10     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12     GNU General Public License for more details.
  13
  14     You should have received a copy of the GNU General Public License
  15     along with this program; if not, write to the Free Software
  16     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  17
  18 */
  19
  20 #include <libcxml/cxml.h>
  21 #include "server_finder.h"
  22 #include "exceptions.h"
  23 #include "util.h"
  24 #include "config.h"
  25 #include "cross.h"
  26 #include "ui_signaller.h"
  27
  28 using std::string;
  29 using std::stringstream;
  30 using boost::shared_ptr;
  31 using boost::scoped_array;
  32
  33 ServerFinder::ServerFinder ()
  34         : _broadcast_thread (0)
  35         , _listen_thread (0)
  36         , _terminate (false)
  37 {
  38         _broadcast_thread = new boost::thread (boost::bind (&ServerFinder::broadcast_thread, this));
  39         _listen_thread = new boost::thread (boost::bind (&ServerFinder::listen_thread, this));
  40 }
  41
  42 ServerFinder::~ServerFinder ()
  43 {
  44         {
  45                 boost::mutex::scoped_lock lm (_mutex);
  46                 _terminate = true;
  47         }
  48
  49         if (_broadcast_thread && _broadcast_thread->joinable ()) {
  50                 _broadcast_thread->join ();
  51         }
  52         delete _broadcast_thread;
  53
  54         if (_listen_thread && _listen_thread->joinable ()) {
  55                 _listen_thread->join ();
  56         }
  57         delete _listen_thread;
  58 }
  59
  60 void
  61 ServerFinder::broadcast_thread ()
  62 {
  63         boost::system::error_code error;
  64         boost::asio::io_service io_service;
  65         boost::asio::ip::udp::socket socket (io_service);
  66         socket.open (boost::asio::ip::udp::v4(), error);
  67         if (error) {
  68                 throw NetworkError ("failed to set up broadcast socket");
  69         }
  70
  71         socket.set_option (boost::asio::ip::udp::socket::reuse_address (true));
  72         socket.set_option (boost::asio::socket_base::broadcast (true));
  73
  74         boost::asio::ip::udp::endpoint end_point (boost::asio::ip::address_v4::broadcast(), Config::instance()->server_port_base() + 1);
  75
  76         while (1) {
  77                 boost::mutex::scoped_lock lm (_mutex);
  78                 if (_terminate) {
  79                         socket.close (error);
  80                         return;
  81                 }
  82
  83                 string data = DCPOMATIC_HELLO;
  84                 socket.send_to (boost::asio::buffer (data.c_str(), data.size() + 1), end_point);
  85
  86                 lm.unlock ();
  87                 dcpomatic_sleep (10);
  88         }
  89 }
  90
  91 void
  92 ServerFinder::listen_thread ()
  93 {
  94         while (1) {
  95                 {
  96                         /* See if we need to stop */
  97                         boost::mutex::scoped_lock lm (_mutex);
  98                         if (_terminate) {
  99                                 return;
 100                         }
 101                 }
 102
 103                 shared_ptr<Socket> sock (new Socket (10));
 104
 105                 try {
 106                         sock->accept (Config::instance()->server_port_base() + 1);
 107                 } catch (std::exception& e) {
 108                         continue;
 109                 }
 110
 111                 uint32_t length = sock->read_uint32 ();
 112                 scoped_array<char> buffer (new char[length]);
 113                 sock->read (reinterpret_cast<uint8_t*> (buffer.get()), length);
 114
 115                 stringstream s (buffer.get());
 116                 shared_ptr<cxml::Document> xml (new cxml::Document ("ServerAvailable"));
 117                 xml->read_stream (s);
 118
 119                 ui_signaller->emit (boost::bind (boost::ref (ServerFound), ServerDescription (
 120                                                          sock->socket().remote_endpoint().address().to_string (),
 121                                                          xml->number_child<int> ("Threads")
 122                                                          )));
 123         }
 124 }