dhtcontrolimpl.java

这是一个基于java编写的torrent的P2P源码

												diversified[j]	= true;
												
												byte[][]	diversified_keys = 
													adapter.diversify( _contact, true, false, encoded_keys[j], _diversifications[j], false );
											
												for (int k=0;k<diversified_keys.length;k++){
												
													put( 	thread_pool,
															diversified_keys[k], 
															"Diversification of [" + description + "]",
															value_sets[j], 
															timeout,
															false,
															keys_written,
															listener );
												}
											}
										}
									}
								}finally{
									
									listener.complete( false );
								}	
							}
							
							public void
							failed(
								DHTTransportContact 	_contact,
								Throwable 				_error )
							{
								try{
									DHTLog.log( "Store failed " + DHTLog.getString( _contact ) + " -> failed: " + _error.getMessage());
																			
									router.contactDead( _contact.getID(), false );
									
								}finally{
									
									listener.complete( true );
								}
							}
							
							public void
							keyBlockRequest(
								DHTTransportContact		contact,
								byte[]					request,
								byte[]					key_signature )
							{
								DHTStorageBlock	key_block = database.keyBlockRequest( null, request, key_signature );
								
								if ( key_block != null ){
									
										// remove this key for any subsequent publishes. Quickest hack
										// is to change it into a random key value - this will be rejected
										// by the recipient as not being close enough anyway
									
									for (int i=0;i<encoded_keys.length;i++){
										
										if ( Arrays.equals( encoded_keys[i], key_block.getKey())){
											
											byte[]	dummy = new byte[encoded_keys[i].length];
											
											new Random().nextBytes( dummy );
											
											encoded_keys[i] = dummy;
										}
									}
								}
							}
						},
						encoded_keys, 
						value_sets );
					
				}catch( Throwable e ){
										
					Debug.printStackTrace(e);
					
				}
			}
		}
	}
	
	public DHTTransportValue
	getLocalValue(
		byte[]		unencoded_key )
	{
		final byte[]	encoded_key = encodeKey( unencoded_key );

		DHTLog.log( "getLocalValue for " + DHTLog.getString( encoded_key ));

		DHTDBValue	res = database.get( new HashWrapper( encoded_key ));
	
		if ( res == null ){
			
			return( null );
		}
		
		return( res );
	}
	
	public void
	get(
		byte[]						unencoded_key,
		String						description,
		byte						flags,
		int							max_values,
		long						timeout,
		boolean						exhaustive,
		boolean						high_priority,
		final DHTOperationListener	get_listener )
	{
		final byte[]	encoded_key = encodeKey( unencoded_key );

		DHTLog.log( "get for " + DHTLog.getString( encoded_key ));
		
		getSupport( encoded_key, description, flags, max_values, timeout, exhaustive, high_priority, new DHTOperationListenerDemuxer( get_listener ));
	}
	
	public boolean
	isDiversified(
		byte[]		unencoded_key )
	{
		final byte[]	encoded_key = encodeKey( unencoded_key );

		return( adapter.isDiversified( encoded_key ));
	}
	
	public boolean
   	lookup(		
   		byte[]							unencoded_key,
   		long							timeout,
   		final DHTOperationListener		lookup_listener )
	{
		final byte[]	encoded_key = encodeKey( unencoded_key );

		DHTLog.log( "lookup for " + DHTLog.getString( encoded_key ));

		final AESemaphore	sem = new AESemaphore( "DHTControl:lookup" );

		final	boolean[]	diversified = { false };
		
		DHTOperationListener	delegate = 
			new DHTOperationListener()
			{
				public void
				searching(
					DHTTransportContact	contact,
					int					level,
					int					active_searches )
				{
					lookup_listener.searching( contact, level, active_searches );
				}
				
				public void
				found(
					DHTTransportContact	contact )
				{
				}
				
				public void
				diversified()
				{
					lookup_listener.diversified();
				}
				
				public void
				read(
					DHTTransportContact	contact,
					DHTTransportValue	value )
				{
				}
				
				public void
				wrote(
					DHTTransportContact	contact,
					DHTTransportValue	value )
				{
				}
				
				public void
				complete(
					boolean				timeout )
				{
					lookup_listener.complete( timeout );
					
					sem.release();
				}
			};
			
		lookup( 	external_lookup_pool, false,
					encoded_key, 
					"lookup",
					(byte)0,
					false, 
					timeout,
					search_concurrency,
					1,
					router.getK(),
					new lookupResultHandler( delegate )
					{
						public void
						diversify(
							DHTTransportContact	cause,
							byte				diversification_type )
						{
							diversified();
							
							diversified[0] = true;
						}
														
						public void
						closest(
							List	closest )
						{
							for (int i=0;i<closest.size();i++){
								
								lookup_listener.found((DHTTransportContact)closest.get(i));
							}
						}
					});
		
		sem.reserve();
				
		return( diversified[0] );
	}
	
	protected void
	getSupport(
		final byte[]						initial_encoded_key,
		final String						description,
		final byte							flags,
		final int							max_values,
		final long							timeout,
		final boolean						exhaustive,
		final boolean						high_priority,
		final DHTOperationListenerDemuxer	get_listener )
	{
			// get the initial starting point for the get - may have previously been diversified
		
		byte[][]	encoded_keys	= adapter.diversify( null, false, true, initial_encoded_key, DHT.DT_NONE, exhaustive );

		for (int i=0;i<encoded_keys.length;i++){
			
			final boolean[]	diversified = { false };

			final byte[]	encoded_key	= encoded_keys[i];
				
			boolean	div = !Arrays.equals( encoded_key, initial_encoded_key );
			
			if ( div ){
				
				get_listener.diversified();
			}
			
			final String	this_description = 
				div?("Diversification of [" + description + "]" ):description;						

			lookup( external_lookup_pool,
					high_priority,
					encoded_key, 
					this_description,
					flags,
					true, 
					timeout,
					search_concurrency * 2,	// double conc for priority gets
					max_values,
					router.getK(),
					new lookupResultHandler( get_listener )
					{
						private List	found_values	= new ArrayList();
							
						public void
						diversify(
							DHTTransportContact	cause,
							byte				diversification_type )
						{
							diversified();
							
								// we only want to follow one diversification
							
							if ( !diversified[0]){
								
								diversified[0] = true;

								int	rem = max_values==0?0:( max_values - found_values.size());
								
								if ( max_values == 0 || rem > 0 ){
									
									byte[][]	diversified_keys = adapter.diversify( cause, false, false, encoded_key, diversification_type, exhaustive );
									
										// should return a max of 1 (0 if diversification refused)
										// however, could change one day to search > 1 
									
									for (int j=0;j<diversified_keys.length;j++){
										
										getSupport( diversified_keys[j], "Diversification of [" + this_description + "]", flags, rem,  timeout, exhaustive, high_priority, get_listener );
									}
								}								
							}
						}
						
						public void
						read(
							DHTTransportContact	contact,
							DHTTransportValue	value )
						{	
							found_values.add( value );
							
							super.read( contact, value );
						}
														
						public void
						closest(
							List	closest )
						{
							/* we don't use teh cache-at-closest kad feature
							if ( found_values.size() > 0 ){
									
								DHTTransportValue[]	values = new DHTTransportValue[found_values.size()];
								
								found_values.toArray( values );
								
									// cache the values at the 'n' closest seen locations
								
								for (int k=0;k<Math.min(cache_at_closest_n,closest.size());k++){
									
									DHTTransportContact	contact = (DHTTransportContact)(DHTTransportContact)closest.get(k);
									
									for (int j=0;j<values.length;j++){
										
										wrote( contact, values[j] );
									}
									
									contact.sendStore( 
											new DHTTransportReplyHandlerAdapter()
											{
												public void
												storeReply(
													DHTTransportContact _contact,
													byte[]				_diversifications )
												{
														// don't consider diversification for cache stores as we're not that
														// bothered
													
													DHTLog.log( "Cache store OK " + DHTLog.getString( _contact ));
													
													router.contactAlive( _contact.getID(), new DHTControlContactImpl(_contact));
												}	
												
												public void
												failed(
													DHTTransportContact 	_contact,
													Throwable 				_error )
												{
													DHTLog.log( "Cache store failed " + DHTLog.getString( _contact ) + " -> failed: " + _error.getMessage());
													
													router.contactDead( _contact.getID(), false );
												}
											},
											new byte[][]{ encoded_key }, 
											new DHTTransportValue[][]{ values });
								}
							}
							*/
						}
					});
		}
	}
		
	public byte[]
	remove(
		byte[]					unencoded_key,
		String					description,
		DHTOperationListener	listener )
	{		
		final byte[]	encoded_key = encodeKey( unencoded_key );

		DHTLog.log( "remove for " + DHTLog.getString( encoded_key ));

		DHTDBValue	res = database.remove( local_contact, new HashWrapper( encoded_key ));
		
		if ( res == null ){
			
				// not found locally, nothing to do
			
			return( null );
			
		}else{
			
				// we remove a key by pushing it back out again with zero length value 
						
			put( 	external_put_pool, 
					encoded_key, 
					description, 
					res,
					0, 
					true, 
					new HashSet(),
					new DHTOperationListenerDemuxer( listener ));
			
			return( res.getValue());
		}
	}
	
		/**
		 * The lookup method returns up to K closest nodes to the target
		 * @param lookup_id
		 * @return
		 */
	
	protected void
	lookup(
		ThreadPool					thread_pool,
		boolean						high_priority,
		final byte[]				lookup_id,
		final String				description,
		final byte					flags,
		final boolean				value_search,
		final long					timeout,
		final int					concurrency,
		final int					max_values,
		final int					search_accuracy,
		final lookupResultHandler	handler )
	{
		thread_pool.run(
			new task(thread_pool)
			{
				public void
				runSupport()
				{
					try{
						lookupSupportSync( lookup_id, flags, value_search, timeout, concurrency, max_values, search_accuracy, handler );
						
					}catch( Throwable e ){
						
						Debug.printStackTrace(e);
					}
				}
				
				public byte[]
				getTarget()
				{
					return( lookup_id ); 
				}
				
				public String
				getDescription()
				{
					return( description );
				}
			}, high_priority );
	}
	
	protected void
	lookupSupportSync(
		final byte[]				lookup_id,
		byte						flags,
		boolean						value_search,
		long						timeout,
		int							concurrency,
		int							max_values,
		final int					search_accuracy,
		final lookupResultHandler	result_handler )
	{
		boolean		timeout_occurred	= false;
	
		last_lookup	= SystemTime.getCurrentTime();
	
		result_handler.incrementCompletes();

		try{
			DHTLog.log( "lookup for " + DHTLog.getString( lookup_id ));
			
			if ( value_search ){
				
				if ( database.isKeyBlocked( lookup_id )){
							
					DHTLog.log( "lookup: terminates - key blocked" );

						// bail out and pretend everything worked with zero results
				
					return;
				}
			}
		
				// keep querying successively closer nodes until we have got responses from the K
				// closest nodes that we've seen. We might get a bunch of closer nodes that then
				// fail to respond, which means we have reconsider further away nodes
			
				// we keep a list of nodes that we have queried to avoid re-querying them
			
				// we keep a list of nodes discovered that we have yet to query
			
				// we have a parallel search limit of A. For each A we effectively loop grabbing
				// the currently closest unqueried node, querying it and adding the results to the
				// yet-to-query-set (unless already queried)
			
				// we terminate when we have received responses from the K closest nodes we know
				// about (excluding failed ones)
			
				// Note that we never widen the root of our search beyond the initial K closest
				// that we know about - this could be relaxed