source: code/trunk/src/libraries/network/packet/Packet.cc @ 12048

/*
 *   ORXONOX - the hottest 3D action shooter ever to exist
 *                    > www.orxonox.net <
 *
 *
 *   License notice:
 *
 *   This program is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU General Public License
 *   as published by the Free Software Foundation; either version 2
 *   of the License, or (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 *   Author:
 *      Oliver Scheuss, (C) 2008
 *   Co-authors:
 *      ...
 *
 */


#include "Packet.h"

#include <cassert>
#include <cstring>
#define WIN32_LEAN_AND_MEAN
#include <enet/enet.h>
#include <boost/thread/mutex.hpp>

#include "util/Output.h"
#include "Acknowledgement.h"
#include "Chat.h"
#include "ClassID.h"
#include "DeleteObjects.h"
#include "FunctionCalls.h"
#include "FunctionIDs.h"
#include "Gamestate.h"
#include "Welcome.h"
#include "network/Host.h"
// #include "network/ClientInformation.h"

namespace orxonox{

namespace packet{

// Make sure we assume the right values
static_assert(static_cast<int>(PacketFlag::Reliable)    == static_cast<int>(ENET_PACKET_FLAG_RELIABLE),    "check enum");
static_assert(static_cast<int>(PacketFlag::Unsequenced) == static_cast<int>(ENET_PACKET_FLAG_UNSEQUENCED), "check enum");
static_assert(static_cast<int>(PacketFlag::NoAllocate)  == static_cast<int>(ENET_PACKET_FLAG_NO_ALLOCATE), "check enum");

#define PACKET_FLAG_DEFAULT PacketFlag::NoAllocate
#define _PACKETID           0

std::map<size_t, Packet *> Packet::packetMap_;
boost::mutex Packet::packetMapMutex_;

Packet::Packet()
{
  flags_ = PACKET_FLAG_DEFAULT;
  packetDirection_ = Direction::Outgoing;
  peerID_=0;
  data_=nullptr;
  enetPacket_=nullptr;
  bDataENetAllocated_ = false;
}

Packet::Packet(uint8_t *data, unsigned int peerID)
{
  flags_ = PACKET_FLAG_DEFAULT;
  packetDirection_ = Direction::Incoming;
  peerID_=peerID;
  data_=data;
  enetPacket_=nullptr;
  bDataENetAllocated_ = false;
}


Packet::Packet(const Packet &p)
{
  enetPacket_=p.enetPacket_;
  flags_=p.flags_;
  packetDirection_ = p.packetDirection_;
  peerID_ = p.peerID_;
  if(p.data_){
    data_ = new uint8_t[p.getSize()];
    memcpy(data_, p.data_, p.getSize());
  }else
    data_=nullptr;
  bDataENetAllocated_ = p.bDataENetAllocated_;
}

/**
@brief
    Destroys a packet completely.

    That also means destroying the ENetPacket if one exists. There
*/
Packet::~Packet()
{
  // Deallocate data_ memory if necessary.
  if (this->bDataENetAllocated_)
  {
    // In this case ENet allocated data_ and will destroy it.
  }
  else if (this->data_)
  {
    // This destructor was probably called as a consequence of ENet executing our callback.
    // It simply serves us to be able to deallocate the packet content (data_) ourselves since
    // we have created it in the first place.
    delete[] this->data_;
  }

  // Destroy the ENetPacket if necessary.
  // Note: For the case ENet used the callback to destroy the packet, we have already set
  // enetPacket_ to nullptr to avoid destroying it again.
  if (this->enetPacket_)
  {
    // enetPacket_->data gets destroyed too by ENet if it was allocated by it.
    enet_packet_destroy(enetPacket_);
  }
}

/**
 * Send the Packet.
 * @param host The host which sends the packet
 */
bool Packet::send(orxonox::Host* host)
{
  // Deny sending incoming packets
  if(packetDirection_ != Direction::Outgoing && packetDirection_ != Direction::Bidirectional )
  {
    assert(0);
    return false;
  }

  if(!enetPacket_)
  {
    // Deny sending empty packets
    if(!data_) {
      assert(0);
      return false;
    }
    // We deliver ENet the data address so that it doesn't memcpy everything again.
    // --> We have to delete data_ ourselves!
    enetPacket_ = enet_packet_create(getData(), getSize(), getFlags());
    enetPacket_->freeCallback = &Packet::deletePacket;
    // Add the packet to a global list so we can access it again once enet calls our
    // deletePacket method. We can of course only give a one argument function to the ENet C library.
    {
      // Assures we don't create a packet and destroy it right after in another thread
      // without having a reference in the packetMap_
      Packet::packetMapMutex_.lock();
      Packet::packetMap_[reinterpret_cast<size_t>(enetPacket_)] = this;
      Packet::packetMapMutex_.unlock();
    }
  }
#ifndef NDEBUG
  switch( *(Type *)(data_ + _PACKETID) )
  {
    case Type::Acknowledgement:
    case Type::Chat:
    case Type::ClassID:
    case Type::Gamestate:
    case Type::Welcome:
    case Type::DeleteObjects:
    case Type::FunctionIDs:
    case Type::FunctionCalls:
      break;
    default:
      assert(0); //there was some error, if this is the case
      break;
  }
#endif

  // Send via reliable or standard channel respectively
  if( this->flags_ & PacketFlag::Reliable )
    host->addPacket( enetPacket_, peerID_, NETWORK_CHANNEL_DEFAULT);
  else
    host->addPacket( enetPacket_, peerID_, NETWORK_CHANNEL_UNRELIABLE);

  return true;
}

/**
 * Given an ENetPacket, create an Orxonox packet
 * @param packet The ENetPacket
 * @param peerID The sender
 */
Packet *Packet::createPacket(ENetPacket* packet, uint32_t peerID)
{
  uint8_t *data = packet->data;
  Packet *p = nullptr;
  switch( *(Type *)(data + _PACKETID) )
  {
    case Type::Acknowledgement:
      p = new Acknowledgement( data, peerID );
      break;
    case Type::Chat:
      p = new Chat( data, peerID );
      break;
    case Type::ClassID:
      p = new ClassID( data, peerID );
      break;
    case Type::Gamestate:
      p = new Gamestate( data, peerID );
      break;
    case Type::Welcome:
      p = new Welcome( data, peerID );
      break;
    case Type::DeleteObjects:
      p = new DeleteObjects( data, peerID );
      break;
    case Type::FunctionCalls:
      p = new FunctionCalls( data, peerID );
      break;
    case Type::FunctionIDs:
      p = new FunctionIDs( data, peerID );
      break;
    default:
      assert(0);
      break;
  }

  // Data was created by ENet
  p->bDataENetAllocated_ = true;
  p->enetPacket_ = packet;

  return p;
}

/**
@brief
    ENet calls this method whenever it wants to destroy a packet that contains
    data we allocated ourselves.
*/
void Packet::deletePacket(ENetPacket *enetPacket)
{
  // Get our Packet from a global map with all Packets created in the send() method of Packet.
  Packet::packetMapMutex_.lock();

  std::map<size_t, Packet*>::iterator it = Packet::packetMap_.find(reinterpret_cast<size_t>(enetPacket));
  assert(it != packetMap_.end());

  // Make sure we don't delete it again in the destructor
  it->second->enetPacket_ = nullptr;
  delete it->second;
  packetMap_.erase(it);

  Packet::packetMapMutex_.unlock();
}

} // namespace packet

} // namespace orxonox