/*
 *  This file is part of the Haven & Hearth game client.
 *  Copyright (C) 2009 Fredrik Tolf <fredrik@dolda2000.com>, and
 *                     Björn Johannessen <johannessen.bjorn@gmail.com>
 *
 *  Redistribution and/or modification of this file is subject to the
 *  terms of the GNU Lesser General Public License, version 3, as
 *  published by the Free Software Foundation.
 *
 *  This program 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.
 *
 *  Other parts of this source tree adhere to other copying
 *  rights. Please see the file `COPYING' in the root directory of the
 *  source tree for details.
 *
 *  A copy the GNU Lesser General Public License is distributed along
 *  with the source tree of which this file is a part in the file
 *  `doc/LPGL-3'. If it is missing for any reason, please see the Free
 *  Software Foundation's website at <http://www.fsf.org/>, or write
 *  to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 *  Boston, MA 02111-1307 USA
 */

package haven;

import java.io.*;
import java.net.*;
import java.nio.channels.ClosedByInterruptException;

/*
 * This is horrible. This code exists to mitigate two bugs in Sun's
 * J2SE.
 *
 * First of all, the standard java.net.Socket implementation is not
 * interruptible per the standard Thread.interrupt mechanism. It is
 * very hard to see that as anything but a bug.
 *
 * Second of all, the java.nio.channels.SocketChannel has a bug on
 * Windows that prevents it from connecting to IPv6 addresses. (The
 * reason for that bug is most likely that Sun has two completely
 * different implementations for the java.net sockets and the NIO
 * sockets, that don't seem to share a single line of code, and they
 * probably missed one of the four functions for creating a socket
 * when making the code IPv6-capable, but that's an aside.)
 *
 * So where does this leave Haven, which uses thread interruption
 * heavily, if I want to be able to connect to IPv6 addresses? Well,
 * in hack-land, of course; where else?
 */
public class HackSocket extends Socket {
    private InputStream in = null;
    private OutputStream out = null;
    private ThreadLocal<InterruptAction> ia = new ThreadLocal<InterruptAction>();
    
    private class InterruptAction implements Runnable {
	private boolean interrupted;

	public void run() {
	    interrupted = true;
	    try {
		HackSocket.this.close();
	    } catch(IOException e) {
		/*
		 * Emm, well... Yeah.
		 *
		 * If the close fails, there isn't really a
		 * lot to do about it, I guess. It's probably
		 * unreasonable to throw exceptions around on
		 * the thread calling interrupt(), though, so
		 * the best action is probably to discard this
		 * exception.
		 */
	    }
	}
    }

    private void hook() {
	Thread ct = Thread.currentThread();
	if(!(ct instanceof HackThread))
	    throw(new RuntimeException("Tried to use an HackSocket on a non-hacked thread."));
	final HackThread ut = (HackThread)ct;
	InterruptAction ia = new InterruptAction();
	ut.addil(ia);
	this.ia.set(ia);
    }
    
    private void release() throws ClosedByInterruptException {
	HackThread ut = (HackThread)Thread.currentThread();
	InterruptAction ia = this.ia.get();
	if(ia == null)
	    throw(new Error("Tried to release a hacked thread without an interrupt handler."));
	ut.remil(ia);
	if(ia.interrupted) {
	    ut.interrupt();
	    throw(new ClosedByInterruptException());
	}
    }

    public void connect(SocketAddress address, int timeout) throws IOException {
	hook();
	try {
	    super.connect(address, timeout);
	} finally {
	    release();
	}
    }
    
    public void connect(SocketAddress address) throws IOException {
	connect(address, 0);
    }
    
    private class HackInputStream extends InputStream {
	private InputStream bk;
	
	private HackInputStream(InputStream bk) {
	    this.bk = bk;
	}
	
	public void close() throws IOException {bk.close();}
	
	public int read() throws IOException {
	    hook();
	    try {
		return(bk.read());
	    } finally {
		release();
	    }
	}
	
	public int read(byte[] buf) throws IOException {
	    hook();
	    try {
		return(bk.read(buf));
	    } finally {
		release();
	    }
	}
	
	public int read(byte[] buf, int off, int len) throws IOException {
	    hook();
	    try {
		return(bk.read(buf, off, len));
	    } finally {
		release();
	    }
	}
    }

    private class HackOutputStream extends OutputStream {
	private OutputStream bk;
	
	private HackOutputStream(OutputStream bk) {
	    this.bk = bk;
	}
	
	public void close() throws IOException {bk.close();}
	public void flush() throws IOException {
	    hook();
	    try {
		bk.flush();
	    } finally {
		release();
	    }
	}
	
	public void write(int b) throws IOException {
	    hook();
	    try {
		bk.write(b);
	    } finally {
		release();
	    }
	}
	
	public void write(byte[] buf) throws IOException {
	    hook();
	    try {
		bk.write(buf);
	    } finally {
		release();
	    }
	}
	
	public void write(byte[] buf, int off, int len) throws IOException {
	    hook();
	    try {
		bk.write(buf, off, len);
	    } finally {
		release();
	    }
	}
    }

    public InputStream getInputStream() throws IOException {
	synchronized(this) {
	    if(in == null)
		in = new HackInputStream(super.getInputStream());
	    return(in);
	}
    }
    
    public OutputStream getOutputStream() throws IOException {
	synchronized(this) {
	    if(out == null)
		out = new HackOutputStream(super.getOutputStream());
	    return(out);
	}
    }
}