recentConnectionReader.cxx

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/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file recentConnectionReader.cxx
 * @author drose
 * @date 2000-06-23
 */

#include "recentConnectionReader.h"
#include "config_net.h"
#include "lightMutexHolder.h"

/**
 *
 */
RecentConnectionReader::
RecentConnectionReader(ConnectionManager *manager) :
  ConnectionReader(manager, 1)
{
  // We should not receive any datagrams before the constructor is done
  // initializing, or our thread may get confused.  Fortunately this should be
  // impossible, because we can't receive datagrams before we call
  // add_connection().
  _available = false;
}

/**
 *
 */
RecentConnectionReader::
~RecentConnectionReader() {
  // We call shutdown() here to guarantee that all threads are gone before the
  // RecentConnectionReader destructs.
  shutdown();
}

/**
 * Returns true if a datagram is available on the queue; call get_data() to
 * extract the datagram.
 */
bool RecentConnectionReader::
data_available() {
  return _available;
}

/**
 * If a previous call to data_available() returned true, this function will
 * return the datagram that has become available.
 *
 * The return value is true if a datagram was successfully returned, or false
 * if there was, in fact, no datagram available.  (This may happen if there
 * are multiple threads accessing the RecentConnectionReader).
 */
bool RecentConnectionReader::
get_data(NetDatagram &result) {
  LightMutexHolder holder(_mutex);
  if (!_available) {
    // Huh.  Nothing after all.
    return false;
  }

  result = _datagram;
  _available = false;
  return true;
}

/**
 * This flavor of RecentConnectionReader::get_data(), works like the other,
 * except that it only fills a Datagram object, not a NetDatagram object.
 * This means that the Datagram cannot be queried for its source Connection
 * and/or NetAddress, but it is useful in all other respects.
 */
bool RecentConnectionReader::
get_data(Datagram &result) {
  NetDatagram nd;
  if (!get_data(nd)) {
    return false;
  }
  result = nd;
  return true;
}

/**
 * An internal function called by ConnectionReader() when a new datagram has
 * become available.  The RecentConnectionReader simply queues it up for later
 * retrieval by get_data().
 */
void RecentConnectionReader::
receive_datagram(const NetDatagram &datagram) {
  if (net_cat.is_debug()) {
    net_cat.debug()
      << "Received datagram of " << datagram.get_length()
      << " bytes\n";
  }

  LightMutexHolder holder(_mutex);
  _datagram = datagram;
  _available = true;
}