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MessageReader.java

/*
   D-Bus Java Implementation
   Copyright (c) 2005-2006 Matthew Johnson

   This program is free software; you can redistribute it and/or modify it
   under the terms of either the GNU Lesser General Public License Version 2 or the
   Academic Free Licence Version 2.1.

   Full licence texts are included in the COPYING file with this program.
*/
package org.freedesktop.dbus;

import static org.freedesktop.dbus.Gettext._;

import java.io.InputStream;
import java.io.IOException;
import java.io.EOFException;
import java.net.SocketTimeoutException;
import java.text.MessageFormat;

import cx.ath.matthew.debug.Debug;
import cx.ath.matthew.utils.Hexdump;

import org.freedesktop.dbus.exceptions.DBusException;
import org.freedesktop.dbus.exceptions.MessageTypeException;
import org.freedesktop.dbus.exceptions.MessageProtocolVersionException;

public class MessageReader
{
   private InputStream in;
   private byte[] buf = null;
   private byte[] tbuf = null;
   private byte[] header = null;
   private byte[] body = null;
   private int[] len = new int[4];
   public MessageReader(InputStream in)
   {
      this.in = in;
   }
   public Message readMessage() throws IOException, DBusException
   {
      int rv;
      /* Read the 12 byte fixed header, retrying as neccessary */
      if (null == buf) { buf = new byte[12]; len[0] = 0; }
      if (len[0] < 12) {
         try { rv = in.read(buf, len[0], 12-len[0]); }
         catch (SocketTimeoutException STe) { return null; }
         if (-1 == rv) throw new EOFException(_("Underlying transport returned EOF"));
         len[0] += rv;
      }
      if (len[0] == 0) return null;
      if (len[0] < 12) {
         if (Debug.debug) Debug.print(Debug.DEBUG, "Only got "+len[0]+" of 12 bytes of header");
         return null;
      }

      /* Parse the details from the header */
      byte endian = buf[0];
      byte type = buf[1];
      byte protover = buf[3];
      if (protover > Message.PROTOCOL) {
         buf = null;
         throw new MessageProtocolVersionException(MessageFormat.format(_("Protocol version {0} is unsupported"), new Object[] { protover }));
      }

      /* Read the length of the variable header */
      if (null == tbuf) { tbuf = new byte[4]; len[1] = 0; }
      if (len[1] < 4) {
         try { rv = in.read(tbuf, len[1], 4-len[1]); }
         catch (SocketTimeoutException STe) { return null; }
         if (-1 == rv) throw new EOFException(_("Underlying transport returned EOF"));
         len[1] += rv;
      }
      if (len[1] < 4) {
         if (Debug.debug) Debug.print(Debug.DEBUG, "Only got "+len[1]+" of 4 bytes of header");
         return null;
      }

      /* Parse the variable header length */
      int headerlen = 0;
      if (null == header) {
         headerlen = (int) Message.demarshallint(tbuf, 0, endian, 4);
         if (0 != headerlen % 8)
            headerlen += 8-(headerlen%8);
      } else
         headerlen = header.length-8;

      /* Read the variable header */
      if (null == header) {
         header = new byte[headerlen+8]; 
         System.arraycopy(tbuf, 0, header, 0, 4);
         len[2] = 0; 
      }
      if (len[2] < headerlen) {
         try { rv = in.read(header, 8+len[2], headerlen-len[2]); }
         catch (SocketTimeoutException STe) { return null; }
         if (-1 == rv) throw new EOFException(_("Underlying transport returned EOF"));
         len[2] += rv;
      }
      if (len[2] < headerlen) {
         if (Debug.debug) Debug.print(Debug.DEBUG, "Only got "+len[2]+" of "+headerlen+" bytes of header");
         return null;
      }

      /* Read the body */
      int bodylen = 0;
      if (null == body) bodylen = (int) Message.demarshallint(buf, 4, endian, 4);
      if (null == body) { body=new byte[bodylen]; len[3] = 0; }
      if (len[3] < body.length) {
         try { rv = in.read(body, len[3], body.length-len[3]); }
         catch (SocketTimeoutException STe) { return null; }
         if (-1 == rv) throw new EOFException(_("Underlying transport returned EOF"));
         len[3] += rv;
      }
      if (len[3] < body.length) {
         if (Debug.debug) Debug.print(Debug.DEBUG, "Only got "+len[3]+" of "+body.length+" bytes of body");
         return null;
      }

      Message m;
      switch (type) {
         case Message.MessageType.METHOD_CALL:
            m = new MethodCall();
            break;
         case Message.MessageType.METHOD_RETURN:
            m = new MethodReturn();
            break;
         case Message.MessageType.SIGNAL:
            m = new DBusSignal();
            break;
         case Message.MessageType.ERROR:
            m = new Error();
            break;
         default:
            throw new MessageTypeException(MessageFormat.format(_("Message type {0} unsupported"), new Object[] {type}));
      }
      if (Debug.debug) {
         Debug.print(Debug.VERBOSE, Hexdump.format(buf));
         Debug.print(Debug.VERBOSE, Hexdump.format(tbuf));
         Debug.print(Debug.VERBOSE, Hexdump.format(header));
         Debug.print(Debug.VERBOSE, Hexdump.format(body));
      }
      try {
         m.populate(buf, header, body);
      } catch (DBusException DBe) {
         if (AbstractConnection.EXCEPTION_DEBUG && Debug.debug) Debug.print(Debug.ERR, DBe);
         buf = null;
         tbuf = null;
         body = null;
         header = null;
         throw DBe;
      } catch (RuntimeException Re) {
         if (AbstractConnection.EXCEPTION_DEBUG && Debug.debug) Debug.print(Debug.ERR, Re);
         buf = null;
         tbuf = null;
         body = null;
         header = null;
         throw Re;
      }
      if (Debug.debug) {
         Debug.print(Debug.INFO, "=> "+m);
      }
      buf = null;
      tbuf = null;
      body = null;
      header = null;
      return m;
   }
   public void close() throws IOException
   {
      if (Debug.debug) Debug.print(Debug.INFO, "Closing Message Reader");
      in.close();
   }
}

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