* gnu/classpath/jdwp/transport/JdwpConnection.java: New file.

From-SVN: r100688

libjava/ChangeLog

 2005-06-06  Keith Seitz  <keiths@redhat.com>
 
 	* gnu/classpath/jdwp/util/Signature.java: New file.
+	* gnu/classpath/jdwp/transport/JdwpConnection.java: New file.
 
 2005-06-05  Anthony Green  <green@redhat.com>
 

libjava/gnu/classpath/jdwp/transport/JdwpConnection.java

+/* JdwpConnection.java -- A JDWP-speaking connection
+   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., 59 Temple Place, Suite 330, Boston, MA
+02111-1307 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 gnu.classpath.jdwp.Jdwp;
+
+import java.io.DataInputStream;
+import java.io.DataOutputStream;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Arrays;
+
+/**
+ * A connection via some transport to some JDWP-speaking entity.
+ * This is also a thread which handles all communications to/from
+ * the debugger. While access to the transport layer may be accessed by
+ * several threads, start-up and initialization should not be allowed
+ * to occur more than once.
+ *
+ * <p>This class is also a thread that is responsible for pulling
+ * packets off the wire and sticking them in a queue for packet
+ * processing threads.
+ * 
+ * @author Keith Seitz (keiths@redhat.com)
+ */
+public class JdwpConnection
+  extends Thread
+{
+  // The JDWP handshake
+  private static final byte[] _HANDSHAKE = {'J', 'D', 'W', 'P', '-', 'H', 'a', 'n', 'd', 's', 'h', 'a', 'k', 'e'};
+
+  // Transport method
+  private ITransport _transport;
+
+  // Command queue
+  private ArrayList _commandQueue;
+
+  // Shutdown flag
+  private boolean _shutdown;
+
+  // Input stream from transport
+  private DataInputStream _inStream;
+
+  // Output stream from transprot
+  private DataOutputStream _outStream;
+
+  /**
+   * Creates a new <code>JdwpConnection</code> instance
+   *
+   * @param transport  the transport to use for communications
+   */
+  public JdwpConnection (ITransport transport)
+  {
+    _transport = transport;
+    _commandQueue = new ArrayList ();
+    _shutdown = false;
+  }
+
+  /**
+   * Initializes the connection, including connecting
+   * to socket or shared memory endpoint
+   *
+   * @throws TransportException if initialization fails
+   */
+  public void initialize ()
+    throws TransportException
+  {
+    // Initialize transport (connect socket, e.g.)
+    _transport.initialize ();
+
+    // Do handshake
+    try
+      {
+	_inStream = new DataInputStream (_transport.getInputStream ());
+	_outStream = new DataOutputStream (_transport.getOutputStream ());
+	_doHandshake ();
+      }
+    catch (IOException ioe)
+      {
+	throw new TransportException (ioe);
+      }
+  }
+
+  /* Does the JDWP handshake -- this should not need synchronization
+     because this is called by VM startup code, i.e., no packet
+     processing threads have started yet. */
+  private void _doHandshake ()
+    throws IOException
+  {
+    // According to the spec, the handshake is always initiated by
+    // the debugger, regardless of whether the JVM is in client mode or
+    // server mode.
+
+    // Wait for handshake from debugger
+    byte[] hshake = new byte[_HANDSHAKE.length];
+    _inStream.readFully (hshake, 0, _HANDSHAKE.length);
+
+    if (Arrays.equals (hshake, _HANDSHAKE))
+      {
+	// Send reply handshake
+	_outStream.write (_HANDSHAKE, 0, _HANDSHAKE.length);
+	return;
+      }
+    else
+      {
+	throw new IOException ("invalid JDWP handshake (\"" + hshake + "\")");
+      }
+  }
+
+  /**
+   * Main run method for the thread. This thread loops waiting for
+   * packets to be read via the connection. When a packet is complete
+   * and ready for processing, it places the packet in a queue that can
+   * be accessed via <code>getPacket</code>
+   */
+  public void run ()
+  {
+    while (!_shutdown)
+      {
+	try
+	  {
+	    _readOnePacket ();
+	  }
+	catch (IOException ioe)
+	  {
+	    /* IOException can occur for two reasons:
+	       1. Lost connection with the other side
+	       2. Transport was shutdown
+	       In either case, we make sure that all of the
+	       back-end gets shutdown. */
+	    Jdwp.getInstance().shutdown ();
+	  }
+	catch (Throwable t)
+	  {
+	    System.out.println ("JdwpConnection.run: caught an exception: "
+				+ t);
+	    // Just keep going
+	  }
+      }
+  }
+
+  // Reads a single packet from the connection, adding it to the packet
+  // queue when a complete packet is ready.
+  private void _readOnePacket ()
+    throws IOException
+  {
+    byte[] data = null;
+
+    // Read in the packet
+    int length = _inStream.readInt ();
+    if (length < 11)
+      {
+	throw new IOException ("JDWP packet length < 11 (" 
+			       + length + ")");
+      }
+
+    data = new byte[length];
+    data[0] = (byte) (length >>> 24);
+    data[1] = (byte) (length >>> 16);
+    data[2] = (byte) (length >>> 8);
+    data[3] = (byte) length;
+    _inStream.readFully (data, 4, length - 4);
+
+    JdwpPacket packet = JdwpPacket.fromBytes (data);
+    if (packet != null)
+      {
+	synchronized (_commandQueue)
+	  {
+	    _commandQueue.add (packet);
+	    _commandQueue.notifyAll ();
+	  }
+      }
+  }
+
+  /**
+   * Returns a packet from the queue of ready packets
+   *
+   * @returns  a <code>JdwpPacket</code> ready for processing
+   *           <code>null</code> when shutting down
+   */
+  public JdwpPacket getPacket ()
+  {
+    synchronized (_commandQueue)
+      {
+	while (_commandQueue.isEmpty ())
+	  {
+	    try
+	      {
+		_commandQueue.wait ();
+	      }
+	    catch (InterruptedException ie)
+	      {
+		/* PacketProcessor is interrupted
+		   when shutting down */
+		return null;
+	      }
+	  }
+
+	return (JdwpPacket) _commandQueue.remove (0);
+      }
+  }
+
+  /**
+   * Send a packet to the debugger
+   *
+   * @param pkt a <code>JdwpPacket</code> to send
+   * @throws TransportException
+   */
+  public void sendPacket (JdwpPacket pkt)
+    throws IOException
+  {
+    byte[] data = pkt.toBytes ();
+    _outStream.write (data, 0, data.length);
+  }
+
+  /**
+   * Shutdown the connection
+   */
+  public void shutdown ()
+  {
+    if (!_shutdown)
+      {
+	_transport.shutdown ();
+	_shutdown = true;
+	interrupt ();
+      }
+  }
+}