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;
}
public class BTMessageDecoder implements MessageStreamDecoder {
private static final int MIN_MESSAGE_LENGTH = 1; // for type id
// private static final int MAX_MESSAGE_LENGTH = 16*1024+128; //should never be > 16KB+9B, as we
// never request chunks > 16KB - update, some LT extensions can be bigger
private static final int MAX_MESSAGE_LENGTH =
128
* 1024; // 17/5/2013: parg: got a huge torrent with so many pieces the bitfield exceeds
// the above limit...
private static final int HANDSHAKE_FAKE_LENGTH =
323119476; // (byte)19 + "Bit" readInt() value of header
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 boolean reading_handshake_message = false;
private int message_length;
private int pre_read_start_buffer;
private int pre_read_start_position;
private boolean last_received_was_keepalive = false;
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;
public BTMessageDecoder() {
/* nothing */
}
public int performStreamDecode(Transport transport, int max_bytes) throws IOException {
try {
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
// throw( new IOException( "BTMessageDecoder already destroyed" ));
break;
}
if (is_paused) {
break;
}
int bytes_possible = preReadProcess(bytes_remaining);
if (bytes_possible < 1) {
Debug.out("ERROR BT: bytes_possible < 1");
break;
}
if (reading_length_mode) {
transport.read(decode_array, 1, 1); // only read into length buffer
} else {
transport.read(
decode_array, 0, 2); // read into payload buffer, and possibly next message length
}
int bytes_read = postReadProcess();
bytes_remaining -= bytes_read;
if (bytes_read < bytes_possible) {
break;
}
if (reading_length_mode && last_received_was_keepalive) {
// hack to stop a 0-byte-read after receiving a keep-alive message
// otherwise we won't realize there's nothing left on the line until trying to read again
last_received_was_keepalive = false;
break;
}
}
return max_bytes - bytes_remaining;
} catch (NullPointerException e) {
// due to lack of synchronization here the buffers can be nullified by a concurrent 'destroy'
// turn this into something less scarey
throw (new IOException("Decoder has most likely been destroyed"));
}
}
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 ByteBuffer destroy() {
if (destroyed) {
Debug.out("Trying to redestroy message decoder, stack trace follows: " + this);
Debug.outStackTrace();
}
is_paused = true;
destroyed = true;
// there's a concurrency issue with the decoder whereby it can be destroyed while will being
// messed with. Don't
// have the energy to look into it properly atm so just try to ensure that it doesn't bork too
// badly (parg: 29/04/2012)
// only occasional but does have potential to generate direct buffer mem leak ;(
int lbuff_read = 0;
int pbuff_read = 0;
length_buffer.limit(SS, 4);
DirectByteBuffer plb = payload_buffer;
if (reading_length_mode) {
lbuff_read = length_buffer.position(SS);
} else { // reading payload
length_buffer.position(SS, 4);
lbuff_read = 4;
pbuff_read = plb == null ? 0 : plb.position(SS);
}
ByteBuffer unused = ByteBuffer.allocate(lbuff_read + pbuff_read); // TODO convert to direct?
length_buffer.flip(SS);
unused.put(length_buffer.getBuffer(SS));
try {
if (plb != null) {
plb.flip(SS);
unused.put(
plb.getBuffer(
SS)); // Got a buffer overflow exception here in the past - related to PEX?
}
} catch (RuntimeException e) {
Debug.out("hit known threading issue");
}
unused.flip();
length_buffer.returnToPool();
if (plb != null) {
plb.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 (RuntimeException e) {
// happens if messages modified by alt thread...
Debug.out("hit known threading issue");
}
messages_last_read.clear();
return unused;
}
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 read = payload_buffer.position(SS) - pre_read_start_position;
if (payload_buffer.position(SS) > 0) { // need to have read the message id first byte
if (BTMessageFactory.getMessageType(payload_buffer) == Message.TYPE_DATA_PAYLOAD) {
data_bytes_read += read;
} else {
prot_bytes_read += read;
}
}
if (!payload_buffer.hasRemaining(SS) && !is_paused) { // full message received!
payload_buffer.position(SS, 0);
DirectByteBuffer ref_buff = payload_buffer;
payload_buffer = null;
if (reading_handshake_message) { // decode handshake
reading_handshake_message = false;
DirectByteBuffer handshake_data =
DirectByteBufferPool.getBuffer(DirectByteBuffer.AL_MSG_BT_HAND, 68);
handshake_data.putInt(SS, HANDSHAKE_FAKE_LENGTH);
handshake_data.put(SS, ref_buff);
handshake_data.flip(SS);
ref_buff.returnToPool();
try {
Message handshake =
MessageManager.getSingleton()
.createMessage(BTMessage.ID_BT_HANDSHAKE_BYTES, handshake_data, (byte) 1);
messages_last_read.add(handshake);
} catch (MessageException me) {
handshake_data.returnToPool();
throw new IOException("BT message decode failed: " + me.getMessage());
}
// we need to auto-pause decoding until we're told to start again externally,
// as we don't want to accidentally read the next message on the stream if it's an
// AZ-format handshake
pauseDecoding();
} else { // decode normal message
try {
messages_last_read.add(createMessage(ref_buff));
} catch (Throwable e) {
ref_buff.returnToPoolIfNotFree();
// maintain unexpected errors as such so they get logged later
if (e instanceof RuntimeException) {
throw ((RuntimeException) e);
}
throw new IOException("BT 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
} 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 == HANDSHAKE_FAKE_LENGTH) { // handshake message
reading_handshake_message = true;
message_length = 64; // restore 'real' length
payload_buffer =
DirectByteBufferPool.getBuffer(DirectByteBuffer.AL_MSG_BT_HAND, message_length);
} else if (message_length == 0) { // keep-alive message
reading_length_mode = true;
last_received_was_keepalive = true;
try {
Message keep_alive =
MessageManager.getSingleton()
.createMessage(BTMessage.ID_BT_KEEP_ALIVE_BYTES, null, (byte) 1);
messages_last_read.add(keep_alive);
} catch (MessageException me) {
throw new IOException("BT message decode failed: " + me.getMessage());
}
} else if (message_length < MIN_MESSAGE_LENGTH || message_length > MAX_MESSAGE_LENGTH) {
throw new IOException(
"Invalid message length given for BT message decode: " + message_length);
} else { // normal message
payload_buffer =
DirectByteBufferPool.getBuffer(DirectByteBuffer.AL_MSG_BT_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;
}
// Overridden by LTMessageDecoder.
protected Message createMessage(DirectByteBuffer ref_buff) throws MessageException {
try {
return BTMessageFactory.createBTMessage(ref_buff);
} catch (MessageException me) {
/*if (identifier != null && me.getMessage() != null && me.getMessage().startsWith("Unknown BT message id")) {
System.out.println(identifier + " " + me.getMessage());
}*/
throw me;
}
}
}
public ByteBuffer destroy() {
if (destroyed) {
Debug.out("Trying to redestroy message decoder, stack trace follows: " + this);
Debug.outStackTrace();
}
is_paused = true;
destroyed = true;
// there's a concurrency issue with the decoder whereby it can be destroyed while will being
// messed with. Don't
// have the energy to look into it properly atm so just try to ensure that it doesn't bork too
// badly (parg: 29/04/2012)
// only occasional but does have potential to generate direct buffer mem leak ;(
int lbuff_read = 0;
int pbuff_read = 0;
length_buffer.limit(SS, 4);
DirectByteBuffer plb = payload_buffer;
if (reading_length_mode) {
lbuff_read = length_buffer.position(SS);
} else { // reading payload
length_buffer.position(SS, 4);
lbuff_read = 4;
pbuff_read = plb == null ? 0 : plb.position(SS);
}
ByteBuffer unused = ByteBuffer.allocate(lbuff_read + pbuff_read); // TODO convert to direct?
length_buffer.flip(SS);
unused.put(length_buffer.getBuffer(SS));
try {
if (plb != null) {
plb.flip(SS);
unused.put(
plb.getBuffer(
SS)); // Got a buffer overflow exception here in the past - related to PEX?
}
} catch (RuntimeException e) {
Debug.out("hit known threading issue");
}
unused.flip();
length_buffer.returnToPool();
if (plb != null) {
plb.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 (RuntimeException e) {
// happens if messages modified by alt thread...
Debug.out("hit known threading issue");
}
messages_last_read.clear();
return unused;
}