/*
* Created on Feb 8, 2005
* Created by Alon Rohter
* Copyright (C) 2004-2005 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.peermanager.messaging.azureus;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import org.gudy.azureus2.core3.util.*;
import com.aelitis.azureus.core.networkmanager.Transport;
import com.aelitis.azureus.core.peermanager.messaging.*;
/**
* Length-prefixed message decoding.
*/
public class AZMessageDecoder implements MessageStreamDecoder {
private static final int MIN_MESSAGE_LENGTH = 6; //4 byte id length + at least 1 byte for id + 1 byte version
private static final int MAX_MESSAGE_LENGTH = 131072; //128K arbitrary limit
private static final byte SS = DirectByteBuffer.SS_MSG;
private DirectByteBuffer payload_buffer = null;
private final DirectByteBuffer length_buffer = DirectByteBufferPool.getBuffer( DirectByteBuffer.AL_MSG, 4 );
private final ByteBuffer[] decode_array = new ByteBuffer[] { null, length_buffer.getBuffer( SS ) };
private boolean reading_length_mode = true;
private int message_length;
private int pre_read_start_buffer;
private int pre_read_start_position;
private volatile boolean destroyed = false;
private volatile boolean is_paused = false;
private ArrayList messages_last_read = new ArrayList();
private int protocol_bytes_last_read = 0;
private int data_bytes_last_read = 0;
private int percent_complete = -1;
private byte[] msg_id_bytes = null;
private boolean msg_id_read_complete = false;
private boolean last_read_made_progress;
private int maximum_message_size = MAX_MESSAGE_LENGTH;
public AZMessageDecoder() {
/*nothing*/
}
public void
setMaximumMessageSize(
int max_bytes )
{
maximum_message_size = max_bytes;
}
public int performStreamDecode( Transport transport, int max_bytes ) throws IOException {
protocol_bytes_last_read = 0;
data_bytes_last_read = 0;
int bytes_remaining = max_bytes;
while( bytes_remaining > 0 ) {
if( destroyed ) {
//destruction currently isn't thread safe so one thread can destroy the decoder (e.g. when closing a connection)
//while the read-controller is still actively processing the us
//Debug.out( "AZ decoder already destroyed: " +transport.getDescription() );
break;
}
if( is_paused ) {
Debug.out( "AZ decoder paused" );
break;
}
int bytes_possible = preReadProcess( bytes_remaining );
if( bytes_possible < 1 ) {
Debug.out( "ERROR AZ: bytes_possible < 1" );
break;
}
long actual_read;
if( reading_length_mode ) {
actual_read = transport.read( decode_array, 1, 1 ); //only read into length buffer
}
else {
actual_read = transport.read( decode_array, 0, 2 ); //read payload buffer, and possibly next message length buffer
}
last_read_made_progress = actual_read > 0;
int bytes_read = postReadProcess();
bytes_remaining -= bytes_read;
if( bytes_read < bytes_possible ) {
break;
}
}
return max_bytes - bytes_remaining;
}
public int getPercentDoneOfCurrentMessage() {
return percent_complete;
}
public Message[] removeDecodedMessages() {
if( messages_last_read.isEmpty() ) return null;
Message[] msgs = (Message[])messages_last_read.toArray( new Message[messages_last_read.size()] );
messages_last_read.clear();
return msgs;
}
public int getProtocolBytesDecoded() { return protocol_bytes_last_read; }
public int getDataBytesDecoded() { return data_bytes_last_read; }
public boolean getLastReadMadeProgress(){ return last_read_made_progress; };
public ByteBuffer destroy() {
is_paused = true;
destroyed = true;
/*
int lbuff_read = 0;
int pbuff_read = 0;
length_buffer.limit( SS, 4 );
if( reading_length_mode ) {
lbuff_read = length_buffer.position( SS );
}
else { //reading payload
length_buffer.position( SS, 4 );
lbuff_read = 4;
pbuff_read = payload_buffer == null ? 0 : payload_buffer.position( SS );
}
ByteBuffer unused = ByteBuffer.allocate( lbuff_read + pbuff_read );
length_buffer.flip( SS );
unused.put( length_buffer.getBuffer( SS ) );
if ( payload_buffer != null ) {
payload_buffer.flip( SS );
unused.put( payload_buffer.getBuffer( SS ) );
}
unused.flip();
*/
length_buffer.returnToPool();
if( payload_buffer != null ) {
payload_buffer.returnToPool();
payload_buffer = null;
}
try{
for( int i=0; i < messages_last_read.size(); i++ ) {
Message msg = (Message)messages_last_read.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 synchronize access
// to this so we'll take the hit here
}
messages_last_read.clear();
//return unused;
return null; //NOTE: we don't bother returning any already-read data
}
private int preReadProcess( int allowed ) {
if( allowed < 1 ) {
Debug.out( "allowed < 1" );
}
decode_array[ 0 ] = payload_buffer == null ? null : payload_buffer.getBuffer( SS ); //ensure the decode array has the latest payload pointer
int bytes_available = 0;
boolean shrink_remaining_buffers = false;
int start_buff = reading_length_mode ? 1 : 0;
boolean marked = false;
for( int i = start_buff; i < 2; i++ ) { //set buffer limits according to bytes allowed
ByteBuffer bb = decode_array[ i ];
if( bb == null ) {
Debug.out( "preReadProcess:: bb["+i+"] == null, decoder destroyed=" +destroyed );
throw( new RuntimeException( "decoder destroyed" ));
}
if( shrink_remaining_buffers ) {
bb.limit( 0 ); //ensure no read into this next buffer is possible
}
else {
int remaining = bb.remaining();
if( remaining < 1 ) continue; //skip full buffer
if( !marked ) {
pre_read_start_buffer = i;
pre_read_start_position = bb.position();
marked = true;
}
if( remaining > allowed ) { //read only part of this buffer
bb.limit( bb.position() + allowed ); //limit current buffer
bytes_available += bb.remaining();
shrink_remaining_buffers = true; //shrink any tail buffers
}
else { //full buffer is allowed to be read
bytes_available += remaining;
allowed -= remaining; //count this buffer toward allowed and move on to the next
}
}
}
return bytes_available;
}
private int postReadProcess() throws IOException {
int prot_bytes_read = 0;
int data_bytes_read = 0;
if( !reading_length_mode && !destroyed ) { //reading payload data mode
//ensure-restore proper buffer limits
payload_buffer.limit( SS, message_length );
length_buffer.limit( SS, 4 );
int curr_position = payload_buffer.position( SS );
int read = curr_position - pre_read_start_position;
if( msg_id_bytes == null && curr_position >= 4 ) { //need to have read the message id length first 4 bytes
payload_buffer.position( SS, 0 );
int id_size = payload_buffer.getInt( SS );
payload_buffer.position( SS, curr_position ); //restore
if( id_size < 1 || id_size > 1024 ) throw new IOException( "invalid id_size [" +id_size+ "]" );
msg_id_bytes = new byte[ id_size ];
}
if( msg_id_bytes != null && curr_position >= msg_id_bytes.length + 4 ) { //need to have also read the message id bytes
if( !msg_id_read_complete ) {
payload_buffer.position( SS, 4 );
payload_buffer.get( SS, msg_id_bytes );
payload_buffer.position( SS, curr_position ); //restore
msg_id_read_complete = true;
}
Message message = MessageManager.getSingleton().lookupMessage( msg_id_bytes );
if ( message == null ){
Debug.out( "Unknown message type '" + new String( msg_id_bytes ) + "'" );
throw( new IOException( "Unknown message type" ));
}
if( message.getType() == Message.TYPE_DATA_PAYLOAD ) {
data_bytes_read += read;
}else{
prot_bytes_read += read;
}
}
else {
prot_bytes_read += read;
}
if( !payload_buffer.hasRemaining( SS ) && !is_paused ) { //full message received!
payload_buffer.position( SS, 0 ); //prepare for use
DirectByteBuffer ref_buff = payload_buffer;
payload_buffer = null;
try {
Message msg = AZMessageFactory.createAZMessage( ref_buff );
messages_last_read.add( msg );
}
catch( Throwable e ) {
ref_buff.returnToPoolIfNotFree();
// maintain unexpected erorrs as such so they get logged later
if ( e instanceof RuntimeException ){
throw((RuntimeException)e );
}
throw new IOException( "AZ message decode failed: " + e.getMessage() );
}
reading_length_mode = true; //see if we've already read the next message's length
percent_complete = -1; //reset receive percentage
msg_id_bytes = null;
msg_id_read_complete = false;
}
else { //only partial received so far
percent_complete = (payload_buffer.position( SS ) * 100) / message_length; //compute receive percentage
}
}
if( reading_length_mode && !destroyed ) {
length_buffer.limit( SS, 4 ); //ensure proper buffer limit
prot_bytes_read += (pre_read_start_buffer == 1) ? length_buffer.position( SS ) - pre_read_start_position : length_buffer.position( SS );
if( !length_buffer.hasRemaining( SS ) ) { //done reading the length
reading_length_mode = false;
length_buffer.position( SS, 0 );
message_length = length_buffer.getInt( SS );
length_buffer.position( SS, 0 ); //reset it for next length read
if( message_length < MIN_MESSAGE_LENGTH || message_length > maximum_message_size ) {
throw new IOException( "Invalid message length given for AZ message decode: " + message_length + " (max=" + maximum_message_size + ")" );
}
payload_buffer = DirectByteBufferPool.getBuffer( DirectByteBuffer.AL_MSG_AZ_PAYLOAD, message_length );
}
}
protocol_bytes_last_read += prot_bytes_read;
data_bytes_last_read += data_bytes_read;
return prot_bytes_read + data_bytes_read;
}
public void pauseDecoding() {
is_paused = true;
}
public void resumeDecoding() {
is_paused = false;
}
}