httpmessagedecoder.java

这是一个基于java编写的torrent的P2P源码

/*
 * Created on 2 Oct 2006
 * Created by Paul Gardner
 * Copyright (C) 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 63.529,40 euros
 * 8 Allee Lenotre, La Grille Royale, 78600 Le Mesnil le Roi, France.
 *
 */

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

import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.*;

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

import com.aelitis.azureus.core.networkmanager.Transport;
import com.aelitis.azureus.core.peermanager.messaging.Message;
import com.aelitis.azureus.core.peermanager.messaging.MessageStreamDecoder;

public class 
HTTPMessageDecoder 
	implements MessageStreamDecoder
{
	private static final int 	MAX_HEADER	= 1024;
	private static final String	NL			= "\r\n";

	private HTTPNetworkConnection	http_connection;
	
	private volatile boolean		paused;
	private volatile boolean		destroyed;
	
	private StringBuffer	header_so_far = new StringBuffer();
	
	private List			messages = new ArrayList();
	
	private int				protocol_bytes_read;
		
	public void
	setConnection(
		HTTPNetworkConnection	_http_connection )
	{
		http_connection	= _http_connection;
		
		if ( destroyed ){
			
			http_connection.destroy();
		}
	}
	
	public int
	performStreamDecode( 
		Transport 	transport, 
		int 		max_bytes ) 
	
		throws IOException
	{
			// before we start message processing we should have had the connection bound
		
		if ( http_connection == null ){
			
			Debug.out( "connection not yet assigned" );
			
			throw( new IOException( "Internal error - connection not yet assigned" ));
		}
		
		// System.out.println( "performStreamDecode" );
		
		protocol_bytes_read	= 0;
		
		int	rem = max_bytes;
		
		byte[]	bytes = new byte[1];
		
		ByteBuffer		bb	= ByteBuffer.wrap( bytes );
		
		ByteBuffer[]	bbs = { bb };
		
		while( rem > 0 && !paused ){
			
			if ( transport.read( bbs,0, 1 ) == 0 ){
				
				break;
			}
			
			rem--;
			
			protocol_bytes_read++;
			
			bb.flip();
			
			char	c = (char)(bytes[0]&0xff);
			
			header_so_far.append( c );
			
			if ( header_so_far.length() > MAX_HEADER ){
				
				throw( new IOException( "HTTP header exceeded maximum of " + MAX_HEADER ));
			}
			
			if ( c == '\n' ){
				
				String	header_str = header_so_far.toString();
				
				if ( header_str.endsWith( NL + NL )){
					
					http_connection.decodeHeader( header_str );
				
					header_so_far.setLength(0);
				}
			}
		}
		
		return( max_bytes - rem );
	}
	  

	
	protected void
	addMessage(
		Message		message )
	{
		synchronized( messages ){
			
			messages.add( message );
		}
		
		http_connection.readWakeup();
	}
	
	public Message[] 
	removeDecodedMessages()
	{
		synchronized( messages ){
			
			if ( messages.isEmpty()){
				
				return null;
			}
			    
			Message[] msgs = (Message[])messages.toArray( new Message[messages.size()] );
			
			messages.clear();
			    
			return( msgs );
		}
	}
	  
	public int 
	getProtocolBytesDecoded()
	{
		return( protocol_bytes_read );
	}
	  
	public int 
	getDataBytesDecoded()
	{
		return( 0 );
	}
	  
	public int 
	getPercentDoneOfCurrentMessage()
	{
		return( 0 );
	}
	  
	public void 
	pauseDecoding()
	{
		paused	= true;
	}
	
	public void 
	resumeDecoding()
	{
		if ( !destroyed ){
			
			paused	= false;
		}
	}
	  
	public ByteBuffer 
	destroy()
	{
		paused		= true;
		destroyed	= true;
		
		if ( http_connection != null ){
		
			http_connection.destroy();
		}
		
	    try{

	    	for( int i=0; i<messages.size(); i++ ){
	    		
	    		Message msg = (Message)messages.get( i );
	    		
			    msg.destroy();
			}
		}catch( IndexOutOfBoundsException e ){
		    	// as access to messages_last_read isn't synchronized we can get this error if we destroy the
		    	// decoder in parallel with messages being removed. We don't really want to synchornized access
		    	// to this so we'll take the hit here
		}
		    
		messages.clear();
		  
		return( null );
	}
}