SquirrelJME/SquirrelJME

// -*- Mode: Java; indent-tabs-mode: t; tab-width: 4 -*-
// ---------------------------------------------------------------------------
// Multi-Phasic Applications: SquirrelJME
//     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
// ---------------------------------------------------------------------------
// SquirrelJME is under the Mozilla Public License Version 2.0.
// See license.mkd for licensing and copyright information.
// ---------------------------------------------------------------------------

package cc.squirreljme.debugger;

import cc.squirreljme.jdwp.JDWPCommLink;
import cc.squirreljme.jdwp.JDWPPacket;
import cc.squirreljme.runtime.cldc.debug.Debugging;
import java.util.Deque;
import java.util.LinkedList;

/**
 * Packet deferral handler.
 *
 * @since 2024/01/26
 */
public class PacketDefer
{
    /** Deferred packets. */
    private final Deque<JDWPPacket> _defer =
        new LinkedList<>();
    
    /**
     * Defers the given packet.
     *
     * @param __link The used link.
     * @param __packet The packet to defer.
     * @throws NullPointerException On null arguments.
     * @since 2024/01/26
     */
    public void defer(JDWPCommLink __link, JDWPPacket __packet)
        throws NullPointerException
    {
        if (__link == null || __packet == null)
            throw new NullPointerException("NARG");
        
        // Store for later
        JDWPPacket copy;
        Deque<JDWPPacket> defer = this._defer;
        synchronized (this)
        {
            // Make a copy of it for later
            copy = __link.getPacket().copyOf(__packet)
                .resetReadPosition();
            
            // Store it
            defer.addLast(copy);
        }
        
        // Debug
        if (JDWPCommLink.DEBUG)
            Debugging.debugNote("Deferring %s (%08x) -> (%08x)...",
                __packet, System.identityHashCode(__packet),
                System.identityHashCode(copy));
    }
    
    /**
     * Removes all the deferred packets.
     *
     * @return The removed packets.
     * @since 2024/01/26
     */
    public JDWPPacket[] removeAll()
    {
        Deque<JDWPPacket> defer = this._defer;
        JDWPPacket[] result;
        synchronized (this)
        {
            if (defer.isEmpty())
                result = null;
            else
                result = defer.toArray(
                    new JDWPPacket[defer.size()]);
            
            // Clear it out
            defer.clear();
        }
        
        // Return all the deferred packets
        return result;
    }
}