dmcheckerimpl.java

这是一个基于java编写的torrent的P2P源码

	 	t.setDaemon(true);
	 	
	 	t.start();
	}
	
	public void 
	enqueueCheckRequest(
		DiskManagerCheckRequest				request,
		DiskManagerCheckRequestListener 	listener )
	{
		enqueueCheckRequest( request, listener, flush_pieces );
	}
	
	protected void 
	enqueueCheckRequest(
		final DiskManagerCheckRequest			request,
		final DiskManagerCheckRequestListener 	listener,
		boolean									read_flush ) 
	{  	
			// everything comes through here - the interceptor listener maintains the piece state and
			// does logging
		
		request.requestStarts();
		
		enqueueCheckRequestSupport( 
				request, 
				new DiskManagerCheckRequestListener() 
				{
					public void 
					checkCompleted( 
						DiskManagerCheckRequest 	request,
						boolean						passed )
					{						
						request.requestEnds( true );

						try{		
							int	piece_number	= request.getPieceNumber();
							
							DiskManagerPiece	piece = disk_manager.getPiece(request.getPieceNumber());
							
							piece.setDone( passed );
							
							if ( passed ){
								
								DMPieceList	piece_list = disk_manager.getPieceList( piece_number );
								
								for (int i = 0; i < piece_list.size(); i++) {
									
									DMPieceMapEntry piece_entry = piece_list.get(i);
										
									piece_entry.getFile().dataChecked( piece_entry.getOffset(), piece_entry.getLength());
								}
							}
						}finally{
							
							listener.checkCompleted( request, passed );
							
							if (Logger.isEnabled()){							
								if ( passed ){
							
									Logger.log(new LogEvent(disk_manager, LOGID, LogEvent.LT_INFORMATION, 
												"Piece " + request.getPieceNumber() + " passed hash check."));
								}else{
									Logger.log(new LogEvent(disk_manager, LOGID, LogEvent.LT_WARNING, 
												"Piece " + request.getPieceNumber() + " failed hash check."));
								}
							}
						}
					}
					 
					public void
					checkCancelled(
						DiskManagerCheckRequest		request )
					{
						
						request.requestEnds( false );

							// don't explicitly mark a piece as failed if we get a cancellation as the 
							// existing state will suffice. Either we're rechecking because it is bad
							// already (in which case it won't be done, or we're doing a recheck-on-complete
							// in which case the state is ok and musn't be flipped to bad 
						
						listener.checkCancelled( request );
							
						if (Logger.isEnabled()){							
							Logger.log(new LogEvent(disk_manager, LOGID, LogEvent.LT_WARNING, 
											"Piece " + request.getPieceNumber() + " hash check cancelled."));
						}	
					}
					
					public void 
					checkFailed( 
						DiskManagerCheckRequest 	request, 
						Throwable		 			cause )
					{						
						request.requestEnds( false );

						try{						
							disk_manager.getPiece(request.getPieceNumber()).setDone( false );
							
						}finally{
							
							listener.checkFailed( request, cause );
							
							if (Logger.isEnabled()){							
								Logger.log(new LogEvent(disk_manager, LOGID, LogEvent.LT_WARNING, 
												"Piece " + request.getPieceNumber() + " failed hash check - " + Debug.getNestedExceptionMessage( cause )));
							}
						}
					}
				}, read_flush );
	}  
	  
	
	protected void
	enqueueCheckRequestSupport(
		final DiskManagerCheckRequest			request,
		final DiskManagerCheckRequestListener	listener,
		boolean									read_flush )
	{
		int	pieceNumber	= request.getPieceNumber();
		
		try{
			
			final byte[]	required_hash = disk_manager.getPieceHash(pieceNumber);
	        
				// quick check that the files that make up this piece are at least big enough
				// to warrant reading the data to check
			
				// also, if the piece is entirely compact then we can immediately
				// fail as we don't actually have any data for the piece (or can assume we don't)
				// we relax this a bit to catch pieces that are part of compact files with less than
				// three pieces as it is possible that these were once complete and have all their bits
				// living in retained compact areas
			
			DMPieceList pieceList = disk_manager.getPieceList(pieceNumber);

			try{
					// there are other comments in the code about the existence of 0 length piece lists
					// just in case these still occur for who knows what reason ensure that a 0 length list
					// causes the code to carry on and do the check (i.e. it is no worse that before this
					// optimisation was added...)
				
				boolean	all_compact = pieceList.size() > 0;
				
				for (int i = 0; i < pieceList.size(); i++) {
					
					DMPieceMapEntry piece_entry = pieceList.get(i);
						
					DiskManagerFileInfoImpl	file_info = piece_entry.getFile();
					
					CacheFile	cache_file = file_info.getCacheFile();
					
					if ( cache_file.compareLength( piece_entry.getOffset()) < 0 ){
							
						listener.checkCompleted( request, false );
						
						return;
					}
					
					if ( all_compact && ( cache_file.getStorageType() != CacheFile.CT_COMPACT || file_info.getNbPieces() <= 2 )){
						
						all_compact = false;
					}
				}
				
				if ( all_compact ){
				
						// System.out.println( "Piece " + pieceNumber + " is all compact, failing hash check" );
					
					listener.checkCompleted( request, false );
					
					return;
				}
				
			}catch( Throwable e ){
			
					// we can fail here if the disk manager has been stopped as the cache file length access may be being
					// performed on a "closed" (i.e. un-owned) file
				
				listener.checkCancelled( request );

				return;
			}
			
			int this_piece_length = pieceNumber < nbPieces - 1 ? pieceLength : lastPieceLength;

			DiskManagerReadRequest read_request = disk_manager.createReadRequest( pieceNumber, 0, this_piece_length );
			
		   	try{
		   		this_mon.enter();
		   	
				if ( stopped ){
					
					listener.checkCancelled( request );
					
					return;
				}
				
				async_reads++;
		   		
		   	}finally{
		   		
		   		this_mon.exit();
		   	}
		   	
		   	read_request.setFlush( read_flush );
		   	
		   	read_request.setUseCache( !request.isAdHoc());
		   	
			disk_manager.enqueueReadRequest( 
				read_request,
				new DiskManagerReadRequestListener()
				{
					public void 
					readCompleted( 
						DiskManagerReadRequest 	read_request, 
						DirectByteBuffer 		buffer )
					{
						complete();
						
					   	try{
					   		this_mon.enter();
					   	
							if ( stopped ){
								
								buffer.returnToPool();
								
								listener.checkCancelled( request );
								
								return;
							}
							
							async_checks++;
					   		
					   	}finally{
					   		
					   		this_mon.exit();
					   	}
						
						try{
					    	final	DirectByteBuffer	f_buffer	= buffer;
					    	
						   	ConcurrentHasher.getSingleton().addRequest(
					    			buffer.getBuffer(DirectByteBuffer.SS_DW),
									new ConcurrentHasherRequestListener()
									{
					    				public void
										complete(
											ConcurrentHasherRequest	hash_request )
					    				{
					    					int	async_result	= 3; // cancelled
					    						    		    					
					    					try{
					    						
												byte[] testHash = hash_request.getResult();
														    								
												if ( testHash != null ){
															
				    								async_result = 1; // success
				    								
				    								for (int i = 0; i < testHash.length; i++){
				    									
				    									if ( testHash[i] != required_hash[i]){
				    										
				    										async_result = 2; // failed;
				    										
				    										break;
				    									}
				    								}
												}
					    					}finally{
					    						
					    						try{
						    						f_buffer.returnToPool();
	
						    						if ( async_result == 1 ){
						    							
						    							listener.checkCompleted( request, true );
						    							
						    						}else if ( async_result == 2 ){
						    							
						    							listener.checkCompleted( request, false );
						    							
						    						}else{
						    							
						    							listener.checkCancelled( request );
						    						}
						    						
					    						}finally{
					    							
					    							try{
					    								this_mon.enter();
					    							
					    								async_checks--;
					    								
					    								if ( stopped ){
					    									  
					    									async_check_sem.release();
					    								}
					    							}finally{
					    								
					    								this_mon.exit();
					    							}
					    						}
					    					}
					    				}
					    				
									},
									request.isLowPriority());
						
					    	
						}catch( Throwable e ){
							
							Debug.printStackTrace(e);
							
    						buffer.returnToPool();
    						
    						listener.checkFailed( request, e );
						}
					}
					  
					public void 
					readFailed( 
						DiskManagerReadRequest 	read_request, 
						Throwable		 		cause )
					{
						complete();
						
						listener.checkFailed( request, cause );
					}
					
					public int
					getPriority()
					{
						return( checking_read_priority?0:-1 );
					}
					
					protected void
					complete()
					{
						try{
							this_mon.enter();

							async_reads--;

							if ( stopped ){

								async_read_sem.release();
							}
						}finally{

							this_mon.exit();
						}
					}
				});
				
		}catch( Throwable e ){
			
			disk_manager.setFailed( "Piece check error - " + Debug.getNestedExceptionMessage(e));
			
			Debug.printStackTrace( e );
			
			listener.checkFailed( request, e );
		}
	}	 
}