Bug 532632 - added guard for disposed shell in BusyIndicator

This is a paranoia check, see comment 20 for an attempt to explain it.

Change-Id: I573410c898470bc725ea820252b4da36ac4bc092
Signed-off-by: Andrey Loskutov <loskutov@gmx.de>

1 files changed, 53 insertions, 43 deletions

diff --git a/bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/BusyIndicator.java b/bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/BusyIndicator.java
index ba5b7a3d52..7fbacc48af 100644
--- a/bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/BusyIndicator.java
+++ b/bundles/org.eclipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/BusyIndicator.java
@@ -27,56 +27,66 @@ public class BusyIndicator {
 	static final String BUSYID_NAME = "SWT BusyIndicator"; //$NON-NLS-1$
 	static final String BUSY_CURSOR = "SWT 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>
- */
+	/**
+	 * 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 == null)
-		SWT.error(SWT.ERROR_NULL_ARGUMENT);
-	if (display == null) {
-		display = Display.getCurrent();
+	public static void showWhile(Display display, Runnable runnable) {
+		if (runnable == null)
+			SWT.error(SWT.ERROR_NULL_ARGUMENT);
 		if (display == null) {
-			runnable.run();
-			return;
+			display = Display.getCurrent();
+			if (display == null) {
+				runnable.run();
+				return;
+			}
 		}
-	}
 
-	Integer busyId = Integer.valueOf(nextBusyId);
-	nextBusyId++;
-	Cursor cursor = display.getSystemCursor(SWT.CURSOR_WAIT);
-	Shell[] shells = display.getShells();
-	for (int i = 0; i < shells.length; i++) {
-		Integer id = (Integer)shells[i].getData(BUSYID_NAME);
-		if (id == null) {
-			shells[i].setCursor(cursor);
-			shells[i].setData(BUSYID_NAME, busyId);
+		Integer busyId = Integer.valueOf(nextBusyId);
+		nextBusyId++;
+		Cursor cursor = display.getSystemCursor(SWT.CURSOR_WAIT);
+		Shell[] shells = display.getShells();
+		for (Shell shell : shells) {
+			Integer id = (Integer)shell.getData(BUSYID_NAME);
+			if (id == null) {
+				setCursorAndId(shell, cursor, busyId);
+			}
 		}
-	}
 
-	try {
-		runnable.run();
-	} finally {
-		shells = display.getShells();
-		for (int i = 0; i < shells.length; i++) {
-			Integer id = (Integer)shells[i].getData(BUSYID_NAME);
-			if (id == busyId) {
-				shells[i].setCursor(null);
-				shells[i].setData(BUSYID_NAME, null);
+		try {
+			runnable.run();
+		} finally {
+			shells = display.getShells();
+			for (Shell shell : shells) {
+				Integer id = (Integer)shell.getData(BUSYID_NAME);
+				if (id == busyId) {
+					setCursorAndId(shell, null, null);
+				}
 			}
 		}
 	}
-}
+
+	/**
+	 * Paranoia code to make sure we don't break UI because of one shell disposed, see bug 532632 comment 20
+	 */
+	private static void setCursorAndId(Shell shell, Cursor cursor, Integer busyId) {
+		if (!shell.isDisposed()) {
+			shell.setCursor(cursor);
+		}
+		if (!shell.isDisposed()) {
+			shell.setData(BUSYID_NAME, busyId);
+		}
+	}
 }