private void doReadAheadLoads() {
    List to_submit = null;
    try {
      lock_mon.enter();

      while (loading_messages.size() + queued_messages.size() < request_read_ahead
          && !requests.isEmpty()
          && !destroyed) {
        DiskManagerReadRequest dmr = (DiskManagerReadRequest) requests.removeFirst();
        loading_messages.add(dmr);
        if (to_submit == null) to_submit = new ArrayList();
        to_submit.add(dmr);
      }
    } finally {
      lock_mon.exit();
    }

    /*
    if ( peer.getIp().equals( "64.71.5.2")){

    	TimeFormatter.milliTrace( "obt read_ahead: -> " + (to_submit==null?0:to_submit.size()) +
    			" [lo=" + loading_messages.size() + ",qm=" + queued_messages.size() + ",re=" + requests.size() + ",rl=" + request_read_ahead + "]");
    }
    */

    if (to_submit != null) {
      for (int i = 0; i < to_submit.size(); i++) {
        peer.getManager()
            .getAdapter()
            .enqueueReadRequest(peer, (DiskManagerReadRequest) to_submit.get(i), read_req_listener);
      }
    }
  }
  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;
  }
  /**
   * Get a list of piece numbers being requested
   *
   * @return list of Long values
   */
  public int[] getRequestedPieceNumbers() {
    if (destroyed) return new int[0];

    /** Cheap hack to reduce (but not remove all) the # of duplicate entries */
    int iLastNumber = -1;
    int pos = 0;
    int[] pieceNumbers;

    try {
      lock_mon.enter();

      // allocate max size needed (we'll shrink it later)
      pieceNumbers = new int[queued_messages.size() + loading_messages.size() + requests.size()];

      for (Iterator iter = queued_messages.keySet().iterator(); iter.hasNext(); ) {
        BTPiece msg = (BTPiece) iter.next();
        if (iLastNumber != msg.getPieceNumber()) {
          iLastNumber = msg.getPieceNumber();
          pieceNumbers[pos++] = iLastNumber;
        }
      }

      for (Iterator iter = loading_messages.iterator(); iter.hasNext(); ) {
        DiskManagerReadRequest dmr = (DiskManagerReadRequest) iter.next();
        if (iLastNumber != dmr.getPieceNumber()) {
          iLastNumber = dmr.getPieceNumber();
          pieceNumbers[pos++] = iLastNumber;
        }
      }

      for (Iterator iter = requests.iterator(); iter.hasNext(); ) {
        DiskManagerReadRequest dmr = (DiskManagerReadRequest) iter.next();
        if (iLastNumber != dmr.getPieceNumber()) {
          iLastNumber = dmr.getPieceNumber();
          pieceNumbers[pos++] = iLastNumber;
        }
      }

    } finally {
      lock_mon.exit();
    }

    int[] trimmed = new int[pos];
    System.arraycopy(pieceNumbers, 0, trimmed, 0, pos);

    return trimmed;
  }
  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;
  }
 public boolean isStalledPendingLoad() {
   return (queued_messages.size() == 0 && loading_messages.size() > 0);
 }
 public int getRequestCount() {
   return (queued_messages.size() + loading_messages.size() + requests.size());
 }