/*

 *                 Sun Public License Notice

 * 

 * The contents of this file are subject to the Sun Public License

 * Version 1.0 (the "License"). You may not use this file except in

 * compliance with the License. A copy of the License is available at

 * http://www.sun.com/

 * 

 * The Original Code is NetBeans. The Initial Developer of the Original

 * Code is Sun Microsystems, Inc. Portions Copyright 1997-2005 Sun

 * Microsystems, Inc. All Rights Reserved.

 */

package org.netbeans.modules.applemenu;

import java.awt.Font;

import java.lang.ref.Reference;

import java.lang.ref.ReferenceQueue;

import java.lang.reflect.Field;

// #57664: Random crash on Mac OS X.  Apple JDK apparently has a bug in 

// the native part of the font handling code.  Font instances seems to share

// native data structures which are released when the instances are finalized.

// Because the native data are shared, their premature release causes random 

// JVM crashes.

//

// This evil hack forces Font.finalize() not to run.  The native font data

// are leaked but it's still better than total crash

class FontReferenceQueue extends ReferenceQueue {

    /**

     * Polls this queue to see if a reference object is available.  If one is

     * available without further delay then it is removed from the queue and

     * returned.  Otherwise this method immediately returns <tt>null</tt>.

     * 

     * @return  A reference object, if one was immediately available,

     *          otherwise <code>null</code>

     */

    public Reference poll() {

        Reference ref;

        for (;;) {

            ref = super.poll();

            if (ref == null)

                break;

            Object obj = ref.get();

            if (! (obj instanceof Font))

                break;

        }

        return ref;

    }

    /**

     * Removes the next reference object in this queue, blocking until either

     * one becomes available or the given timeout period expires.

     * 

     * <p> This method does not offer real-time guarantees: It schedules the

     * timeout as if by invoking the {@link Object#wait(long)} method.

     * 

     * @param  timeout  If positive, block for up <code>timeout</code>

     *                  milliseconds while waiting for a reference to be

     *                  added to this queue.  If zero, block indefinitely.

     * 

     * @return  A reference object, if one was available within the specified

     *          timeout period, otherwise <code>null</code>

     * 

     * @throws  IllegalArgumentException

     *          If the value of the timeout argument is negative

     * 

     * @throws  InterruptedException

     *          If the timeout wait is interrupted

     */

    public Reference remove(long timeout) throws IllegalArgumentException, InterruptedException {

        // timeout is not handled correctly, but good enough for our purposes

        Reference ref;

        for (;;) {

            ref = super.remove(timeout);

            if (ref == null)

                break;

            Object obj = ref.get();

            if (! (obj instanceof Font))

                break;

        }

        return ref;

    }

    static void install() {

        try {

            Class clzz = Class.forName("java.lang.ref.Finalizer");  // NOI18N

            Field fld = clzz.getDeclaredField("queue");  // NOI18N

            fld.setAccessible(true);

            fld.set(null, new FontReferenceQueue());

        } catch (NoClassDefFoundError ex) {

            // ex.printStackTrace();

        } catch (ClassNotFoundException ex) {

            // ex.printStackTrace();

        } catch (Exception ex) {

            // ex.printStackTrace();

        }

    }

}

            FontReferenceQueue.install();