SMBSrvPacketQueue.java

/*
 * Copyright (C) 2006-2008 Alfresco Software Limited.
 *
 * 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.

 * As a special exception to the terms and conditions of version 2.0 of 
 * the GPL, you may redistribute this Program in connection with Free/Libre 
 * and Open Source Software ("FLOSS") applications as described in Alfresco's 
 * FLOSS exception.  You should have recieved a copy of the text describing 
 * the FLOSS exception, and it is also available here: 
 * http://www.alfresco.com/legal/licensing"
 */

package org.alfresco.jlan.smb.server;

import java.util.ArrayList;

/**
 * SMB Packet Queue Class
 * 
 * <p>Packet queue used for asynchronous I/O queueing.
 * 
 * @author gkspencer
 */
public class SMBSrvPacketQueue {

	// Queue of pending CIFS response packets
	
	private ArrayList<QueuedSMBPacket> m_pktQueue;
	
	/**
	 * Queued SMB Packet Class
	 */
	public class QueuedSMBPacket {
		
		// SMB response details
		
		private SMBSrvPacket m_pkt;
		private int m_offset;
		private int m_len;
		private boolean m_writeRaw;
		
		/**
		 * Class constructor
		 * 
		 * @param pkt SMBSrvPacket
		 * 2param offset int
		 * @param len int
		 * @param writeRaw boolean
		 */
		public QueuedSMBPacket( SMBSrvPacket pkt, int offset, int len, boolean writeRaw) {
			m_pkt      = pkt;
			m_offset   = offset;
			m_len      = len;
			m_writeRaw = writeRaw;
		}
		
		/**
		 * Return the SMB packet
		 * 
		 * @return SMBSrvPacket
		 */
		public final SMBSrvPacket getPacket() {
			return m_pkt;
		}
		
		/**
		 * Return the write buffer offset
		 * 
		 * @return int
		 */
		public final int getWriteOffset() {
			return m_offset;
		}
		
		/**
		 * Return the write request length
		 * 
		 * @return int
		 */
		public final int getWriteLength() {
			return m_len;
		}
		
		/**
		 * Return the write raw flag
		 * 
		 * @return boolean
		 */
		public final boolean hasWriteRaw() {
			return m_writeRaw;
		}
		
		/**
		 * Update the queued packet details
		 * 
		 * @param offset int
		 * @param len int
		 */
		public final void updateSettings( int offset, int len) {
			m_offset = offset;
			m_len    = len;
		}
	}
	
	/**
	 * Default constructor
	 */
	public SMBSrvPacketQueue() {
		m_pktQueue = new ArrayList<QueuedSMBPacket>();
	}
	
	/**
	 * Add an SMB packet to the queue
	 * 
	 * @param pkt SMBSrvPacket
	 * @param offset int
	 * @param len int
	 * @param writeRaw boolean
	 */
	public final synchronized void addToQueue( SMBSrvPacket pkt, int offset, int len, boolean writeRaw) {
		
		// Mark the packet as queued
		
		pkt.setQueuedForAsyncIO( true);
		
		// Add to the queue of pending packets
		
		m_pktQueue.add( new QueuedSMBPacket( pkt, offset, len, writeRaw));
	}
	
	/**
	 * Remove an SMB packet from the head of the queue
	 * 
	 * @return QueuedSMBPacket
	 */
	public final synchronized QueuedSMBPacket removeFromQueue() {
		return m_pktQueue.remove( 0);
	}

	/**
	 * Return the request at the head of the queue without removing from the queue
	 * 
	 * @return QueuedSMBPacket
	 */
	public final synchronized QueuedSMBPacket getHeadOfQueue() {
		return m_pktQueue.get( 0);
	}
	
	/**
	 * Return the count of packets in the queue
	 * 
	 *  @return int
	 */
	public final synchronized int numberOfPackets() {
		return m_pktQueue.size();
	}
	
	/**
	 * Return the queue details as a string
	 * 
	 * @return String
	 */
	public String toString() {
		StringBuilder str = new StringBuilder();
		
		str.append("[QueueLen=");
		str.append( numberOfPackets());
		str.append(":");
		
		if ( numberOfPackets() > 0) {
			
			// Dump the first few packet types from the queue
			
			int idx = 0;
			
			while ( idx < 5 && idx < m_pktQueue.size()) {
				str.append( idx);
				str.append( "=");
				str.append( m_pktQueue.get( idx).getPacket().getPacketTypeString());
				str.append(",");
			}
		}
		str.append("]");
		
		return str.toString();
	}
}