/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/
module dwt.custom.BusyIndicator;



import dwt.DWT;
import dwt.graphics.Cursor;
import dwt.widgets.Display;
import dwt.widgets.Shell;
import dwt.dwthelper.Runnable;
import dwt.dwthelper.utils;

/**
 * Support for showing a Busy Cursor during a long running process.
 *
 * @see <a href="http://www.eclipse.org/swt/snippets/#busyindicator">BusyIndicator snippets</a>
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 */
public class BusyIndicator {

    static int nextBusyId = 1;
    static const String BUSYID_NAME = "DWT BusyIndicator"; //$NON-NLS-1$
    static const String BUSY_CURSOR = "DWT BusyIndicator Cursor"; //$NON-NLS-1$

/**
 * Runs the given <code>Runnable</code> while providing
 * busy feedback using this busy indicator.
 *
 * @param display the display on which the busy feedback should be
 *        displayed.  If the display is null, the Display for the current
 *        thread will be used.  If there is no Display for the current thread,
 *        the runnable code will be executed and no busy feedback will be displayed.
 * @param runnable the runnable for which busy feedback is to be shown.
 *        Must not be null.
 *
* @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the runnable is null</li>
 * </ul>
 */

public static void showWhile(Display display, Runnable runnable) {
    if (runnable is null)
        DWT.error(DWT.ERROR_NULL_ARGUMENT);
    if (display is null) {
        display = Display.getCurrent();
        if (display is null) {
            runnable.run();
            return;
        }
    }

    Integer busyId = new Integer(nextBusyId);
    nextBusyId++;
    Cursor cursor = display.getSystemCursor(DWT.CURSOR_WAIT);
    Shell[] shells = display.getShells();
    for (int i = 0; i < shells.length; i++) {
        Integer id = cast(Integer)shells[i].getData(BUSYID_NAME);
        if (id is null) {
            shells[i].setCursor(cursor);
            shells[i].setData(BUSYID_NAME, busyId);
        }
    }

    try {
        runnable.run();
    } finally {
        shells = display.getShells();
        for (int i = 0; i < shells.length; i++) {
            Integer id = cast(Integer)shells[i].getData(BUSYID_NAME);
            if ( id !is null && id == busyId) {
                shells[i].setCursor(null);
                shells[i].setData(BUSYID_NAME, null);
            }
        }
    }
}
}