multipeeruploader.java

这是一个基于java编写的torrent的P2P源码

/*
 * Created on Sep 28, 2004
 * Created by Alon Rohter
 * Copyright (C) 2004, 2005, 2006 Aelitis, All Rights Reserved.
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 * 
 * AELITIS, SAS au capital de 46,603.30 euros
 * 8 Allee Lenotre, La Grille Royale, 78600 Le Mesnil le Roi, France.
 *
 */

package com.aelitis.azureus.core.networkmanager.impl;

import java.util.*;

import org.gudy.azureus2.core3.util.*;

import com.aelitis.azureus.core.networkmanager.*;
import com.aelitis.azureus.core.peermanager.messaging.*;



/**
 * A rate-controlled write entity backed by multiple peer connections, with an
 * emphasis on transmitting packets with full payloads, i.e. it writes to the
 * transport in mss-sized chunks if at all possible. It also employs fair,
 * round-robin write scheduling, where connections each take turns writing a
 * single full packet per round.
 */
public class MultiPeerUploader implements RateControlledEntity {
  private static final int FLUSH_CHECK_LOOP_TIME = 500;  //500ms
  private static final int FLUSH_WAIT_TIME = 3*1000;  //3sec no-new-data wait before forcing write flush
  private long last_flush_check_time = 0;
  
  
  private final RateHandler rate_handler;
  private boolean destroyed = false;
  
  private final HashMap waiting_connections = new HashMap();
  private final LinkedList ready_connections = new LinkedList();
  private final AEMonitor lists_lock = new AEMonitor( "PacketFillingMultiPeerUploader:lists_lock" );
  

  /**
   * Create a new packet-filling multi-peer upload entity,
   * rate-controlled by the given handler.
   * @param rate_handler listener to handle upload rate limits
   */
  public MultiPeerUploader( RateHandler rate_handler ) {
    this.rate_handler = rate_handler;
  }
  
  
  /**
   * Checks the connections in the waiting list to see if it's time to be force-flushed.
   */
  private void flushCheck() {
    long diff = SystemTime.getCurrentTime() - last_flush_check_time;
    
    if( !destroyed && (diff > FLUSH_CHECK_LOOP_TIME || diff < 0 ) ) {
      try {  lists_lock.enter();
        long current_time = SystemTime.getCurrentTime();
        
        for( Iterator i = waiting_connections.entrySet().iterator(); i.hasNext(); ) {
          Map.Entry entry = (Map.Entry)i.next();
          PeerData peer_data = (PeerData)entry.getValue();
          
          long wait_time = current_time - peer_data.last_message_added_time;
          
          if( wait_time > FLUSH_WAIT_TIME || wait_time < 0 ) {  //time to force flush
        	  NetworkConnectionBase conn = (NetworkConnectionBase)entry.getKey();
            
            if( conn.getOutgoingMessageQueue().getTotalSize() > 0 ) { //has data to flush
              conn.getOutgoingMessageQueue().cancelQueueListener( peer_data.queue_listener ); //cancel the listener
              i.remove();  //remove from the waiting list
              addToReadyList( conn );
            }
            else { //no data, so reset flush wait time
              peer_data.last_message_added_time = current_time;
            }
          }
        }
      }
      finally {  lists_lock.exit();  }
      
      last_flush_check_time = SystemTime.getCurrentTime();
    }
  }
  
  
  
  /**
   * Destroy this upload entity.
   * Note: Removes all peer connections in the process.
   */
  public void destroy() {
    destroyed = true;
    
    try {
      lists_lock.enter();
      
      //remove and cancel all connections in waiting list    
      for( Iterator i = waiting_connections.entrySet().iterator(); i.hasNext(); ) {
        Map.Entry entry = (Map.Entry)i.next();
        NetworkConnectionBase conn = (NetworkConnectionBase)entry.getKey();
        PeerData data = (PeerData)entry.getValue();
        conn.getOutgoingMessageQueue().cancelQueueListener( data.queue_listener );
      }
      waiting_connections.clear();
      
      //remove from ready list
      ready_connections.clear();
    }
    finally {
      lists_lock.exit();
    }
  }
  

  
  
  /**
   * Add the given connection to be managed by this upload entity.
   * @param peer_connection to be write managed
   */
  public void addPeerConnection( NetworkConnectionBase peer_connection ) {
    int mss_size = peer_connection.getMssSize();
    boolean has_urgent_data = peer_connection.getOutgoingMessageQueue().hasUrgentMessage();
    int num_bytes_ready = peer_connection.getOutgoingMessageQueue().getTotalSize();
    
    if( num_bytes_ready >= mss_size || has_urgent_data ) {  //has a full packet's worth, or has urgent data
      addToReadyList( peer_connection );
    }
    else {   //has data to send, but not enough for a full packet
      addToWaitingList( peer_connection );
    }
  }
  
  
  /**
   * Remove the given connection from this upload entity.
   * @param peer_connection to be removed
   * @return true if the connection was found and removed, false if not removed
   */
  public boolean removePeerConnection( NetworkConnectionBase peer_connection ) {
    try {
      lists_lock.enter();
      
      //look for the connection in the waiting list and cancel listener if found
      PeerData peer_data = (PeerData)waiting_connections.remove( peer_connection );
      if( peer_data != null ) {
        peer_connection.getOutgoingMessageQueue().cancelQueueListener( peer_data.queue_listener );
        return true;
      }
      
      //look for the connection in the ready list
      if( ready_connections.remove( peer_connection ) ) {
        return true;
      }
      
      return false;
    }
    finally {
      lists_lock.exit();
    }
  }
  
  
  

  //connections with less than a packet's worth of data
  private void addToWaitingList( final NetworkConnectionBase conn ) {
    final PeerData peer_data = new PeerData();
    
    OutgoingMessageQueue.MessageQueueListener listener = new OutgoingMessageQueue.MessageQueueListener() {
      public boolean messageAdded( Message message ) {  return true;  }
      
      public void messageQueued( Message message ) {  //connection now has more data to send
        try {
          lists_lock.enter();
          
          if( waiting_connections.get( conn ) == null ) {  //connection has already been removed from the waiting list
            return;  //stop further processing
          }
          
          int mss_size = conn.getMssSize();
          boolean has_urgent_data = conn.getOutgoingMessageQueue().hasUrgentMessage();
          int num_bytes_ready = conn.getOutgoingMessageQueue().getTotalSize();
        
          if( num_bytes_ready >= mss_size || has_urgent_data ) {  //has a full packet's worth, or has urgent data
            waiting_connections.remove( conn );  //remove from waiting list
            conn.getOutgoingMessageQueue().cancelQueueListener( this ); //cancel this listener
            addToReadyList( conn );
          }
          else {  //still not enough data for a full packet
            peer_data.last_message_added_time = SystemTime.getCurrentTime();  //update last message added time
          }
        }
        finally {
          lists_lock.exit();
        }
      }

      public void messageRemoved( Message message ) {/*ignore*/}
      public void messageSent( Message message ) {/*ignore*/}
      public void protocolBytesSent( int byte_count ) {/*ignore*/}
      public void dataBytesSent( int byte_count ) {/*ignore*/}
    };
    
    peer_data.queue_listener = listener;  //attach listener
    peer_data.last_message_added_time = SystemTime.getCurrentTime(); //start flush wait time
    
    try {
      lists_lock.enter();
      
      waiting_connections.put( conn, peer_data ); //add to waiting list
      conn.getOutgoingMessageQueue().registerQueueListener( listener );  //listen for added data
    }
    finally {
      lists_lock.exit();
    }
  }
  
  
  
  //connections ready to write
  private void addToReadyList( final NetworkConnectionBase conn ) {
    try {
      lists_lock.enter();
      
      ready_connections.addLast( conn );  //add to ready list
    }
    finally {
      lists_lock.exit();
    }
  }
  
  
  
  private int write( EventWaiter waiter, int num_bytes_to_write ) {  //TODO: model this class after the simplicity of MultiPeerDownloader
    if( num_bytes_to_write < 1 ) {
      Debug.out( "num_bytes_to_write < 1" );