| /* JdwpPacket.java -- Base class for JDWP command and reply packets |
| Copyright (C) 2005 Free Software Foundation |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath 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, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA |
| 02110-1301 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package gnu.classpath.jdwp.transport; |
| |
| import java.io.DataOutputStream; |
| import java.io.IOException; |
| |
| /** |
| * All command and reply packets in JDWP share |
| * common header type information: |
| * |
| * length (4 bytes) : size of entire packet, including length |
| * id (4 bytes) : unique packet id |
| * flags (1 byte) : flag byte |
| * [command packet stuff | reply packet stuff] |
| * data (variable) : unique command-/reply-specific data |
| * |
| * This class deal with everything except the command- and reply-specific |
| * data, which get handled in {@link |
| * gnu.classpath.jdwp.transport.JdwpCommandPacket} and {@link |
| * gnu.classpath.jdwp.transport.JdwpReplyPacket}. |
| * |
| * @author Keith Seitz <keiths@redhat.com> |
| */ |
| public abstract class JdwpPacket |
| { |
| // Last id of packet constructed |
| protected static int _last_id = 0; |
| |
| // JDWP reply packet flag |
| protected static final int JDWP_FLAG_REPLY = 0x80; |
| |
| /** |
| * Minimum packet size excluding sub-class data |
| * ( length (4) + id (4) + flags (1) ) |
| */ |
| protected static final int MINIMUM_SIZE = 9; |
| |
| /** |
| * Id of command/reply |
| */ |
| protected int _id; |
| |
| /** |
| * Packet flags |
| */ |
| protected byte _flags; |
| |
| /** |
| * Packet-specific data |
| */ |
| protected byte[] _data; |
| |
| /** |
| * Constructor |
| */ |
| public JdwpPacket () |
| { |
| // By default, DON'T assign an id. This way when a packet |
| // is constructed from fromBytes, _last_id won't increment (i.e., |
| // it won't leave holes in the outgoing packet ids). |
| } |
| |
| /** |
| * Constructs a <code>JdwpPacket</code> with the id |
| * from the given packet. |
| * |
| * @param pkt a packet whose id will be used in this new packet |
| */ |
| public JdwpPacket (JdwpPacket pkt) |
| { |
| _id = pkt.getId (); |
| } |
| |
| /** |
| * Returns the packet id |
| */ |
| public int getId () |
| { |
| return _id; |
| } |
| |
| /** |
| * Sets the packet id |
| */ |
| public void setId (int id) |
| { |
| _id = id; |
| } |
| |
| /** |
| * Returns the packet flags |
| */ |
| public byte getFlags () |
| { |
| return _flags; |
| } |
| |
| /** |
| * Sets the packet flags |
| */ |
| public void setFlags (byte flags) |
| { |
| _flags = flags; |
| } |
| |
| /** |
| * Gets the command/reply-specific data in this packet |
| */ |
| public byte[] getData () |
| { |
| return _data; |
| } |
| |
| /** |
| * Sets the command/reply-specific data in this packet |
| */ |
| public void setData (byte[] data) |
| { |
| _data = data; |
| } |
| |
| /** |
| * Returns the length of this entire packet |
| */ |
| public int getLength () |
| { |
| return MINIMUM_SIZE + (_data == null ? 0 : _data.length); |
| } |
| |
| /** |
| * Allow subclasses to initialize from data |
| * |
| * @param bytes packet data from the wire |
| * @param index index into <code>bytes</code> to start processing |
| * @return number of bytes in <code>bytes</code> processed |
| */ |
| protected abstract int myFromBytes (byte[] bytes, int index); |
| |
| /** |
| * Convert the given bytes into a <code>JdwpPacket</code>. Uses the |
| * abstract method <code>myFromBytes</code> to allow subclasses to |
| * process data. |
| * |
| * If the given data does not represent a valid JDWP packet, it returns |
| * <code>null</code>. |
| * |
| * @param bytes packet data from the wire |
| * @return number of bytes in <code>bytes</code> processed |
| */ |
| public static JdwpPacket fromBytes (byte[] bytes) |
| { |
| int i = 0; |
| int length = ((bytes[i++] & 0xff) << 24 | (bytes[i++] & 0xff) << 16 |
| | (bytes[i++] & 0xff) << 8 | (bytes[i++] & 0xff)); |
| int id = 0; |
| byte flags = 0; |
| |
| if (bytes.length == length) |
| { |
| id = ((bytes[i++] & 0xff) << 24 | (bytes[i++] & 0xff) << 16 |
| | (bytes[i++] & 0xff) << 8 | (bytes[i++] & 0xff)); |
| flags = bytes[i++]; |
| |
| Class clazz = null; |
| if (flags == 0) |
| clazz = JdwpCommandPacket.class; |
| else if ((flags & JDWP_FLAG_REPLY) != 0) |
| clazz = JdwpReplyPacket.class; |
| else |
| { |
| // Malformed packet. Discard it. |
| return null; |
| } |
| |
| JdwpPacket pkt = null; |
| try |
| { |
| pkt = (JdwpPacket) clazz.newInstance (); |
| } |
| catch (InstantiationException ie) |
| { |
| // Discard packet |
| return null; |
| } |
| catch (IllegalAccessException iae) |
| { |
| // Discard packet |
| return null; |
| } |
| |
| pkt.setId (id); |
| pkt.setFlags (flags); |
| |
| i += pkt.myFromBytes (bytes, i); |
| byte[] data = new byte[length - i]; |
| System.arraycopy (bytes, i, data, 0, data.length); |
| pkt.setData (data); |
| |
| return pkt; |
| } |
| |
| return null; |
| } |
| |
| /** |
| * Put subclass information onto the stream |
| * |
| * @param dos the output stream to which to write |
| */ |
| protected abstract void myWrite (DataOutputStream dos) |
| throws IOException; |
| |
| /** |
| * Writes the packet to the output stream |
| * |
| * @param dos the output stream to which to write the packet |
| */ |
| public void write (DataOutputStream dos) |
| throws IOException |
| { |
| // length |
| int length = getLength (); |
| dos.writeInt (length); |
| |
| // ID |
| dos.writeInt (getId ()); |
| |
| // flag |
| dos.writeByte (getFlags ()); |
| |
| // packet-specific stuff |
| myWrite (dos); |
| |
| // data (if any) |
| byte[] data = getData (); |
| if (data != null && data.length > 0) |
| dos.write (data, 0, data.length); |
| } |
| } |