Bug 547093 - [GTK] GNOME logoff hangs for 90 seconds after System.exit() on SWT.Dispose for Display

Change 1
--------
Fixed the session manager hang.

It started to happen after Bug 531634, on GNOME only.

The problem is caused by a combination of System.exit() during
'SWT.Dispose' for 'Display' in SWT application and an oversight in
GNOME session-manager [1].

Due to System.exit() SWT's 'SessionManagerDBus' doesn't have a chance to
respond with 'EndSessionResponse' and GNOME's session manager gets stuck
waiting for the reply.

Change 2
--------
Removed lock from APIs needed in shutdown hook to avoid the deadlock.
Lock is a problem because java's shutdown hooks are implemented as
separate threads, and the main thread will hold lock, because
session manager signals are dispatched in 'g_main_context_iteration'.
The lock shouldn't be used so often anyway, see Bug 546743.

Change 3
--------
Fixed incorrect behavior when QueryEndSession shows a message box
and when user closes it, QueryEndSession timeout elapsed and
session manager expects answer to EndSession instead.

[1] https://gitlab.gnome.org/GNOME/gnome-session/merge_requests/15

Change-Id: I891f2b15830caafc73ccfa6491a8f21c2bbc0160
Signed-off-by: Alexandr Miloslavskiy <alexandr.miloslavskiy@syntevo.com>

1 files changed, 56 insertions, 0 deletions

diff --git a/tests/org.eclipse.swt.tests.gtk/ManualTests/org/eclipse/swt/tests/gtk/snippets/Bug547093_LogoffStuck.java b/tests/org.eclipse.swt.tests.gtk/ManualTests/org/eclipse/swt/tests/gtk/snippets/Bug547093_LogoffStuck.java
new file mode 100644
index 0000000000..9effebffa8
--- /dev/null
+++ b/tests/org.eclipse.swt.tests.gtk/ManualTests/org/eclipse/swt/tests/gtk/snippets/Bug547093_LogoffStuck.java
@@ -0,0 +1,56 @@
+/*******************************************************************************

+ * Copyright (c) 2019 Syntevo and others. All rights reserved.

+ * The contents of this file are made available under the terms

+ * of the GNU Lesser General Public License (LGPL) Version 2.1 that

+ * accompanies this distribution (lgpl-v21.txt).  The LGPL is also

+ * available at http://www.gnu.org/licenses/lgpl.html.  If the version

+ * of the LGPL at http://www.gnu.org is different to the version of

+ * the LGPL accompanying this distribution and there is any conflict

+ * between the two license versions, the terms of the LGPL accompanying

+ * this distribution shall govern.

+ *

+ * Contributors:

+ *     Syntevo - initial API and implementation

+ *******************************************************************************/

+package org.eclipse.swt.tests.gtk.snippets;

+

+import org.eclipse.swt.SWT;

+import org.eclipse.swt.layout.FillLayout;

+import org.eclipse.swt.widgets.Display;

+import org.eclipse.swt.widgets.Label;

+import org.eclipse.swt.widgets.Shell;

+

+public class Bug547093_LogoffStuck {

+	public static void main (String [] args) {

+		Display display = new Display ();

+

+		Shell shell = new Shell (display);

+		shell.setLayout(new FillLayout());

+		shell.setSize(300, 200);

+

+		display.addListener(SWT.Dispose, event -> {

+			/*

+			 * System.exit() prevents org.eclipse.swt.internal.SessionManagerDBus

+			 * from sending reply to session manager and it gets stuck waiting for

+			 * that reply.

+			 */

+			System.exit(0);

+		});

+

+		final Label label = new Label(shell, SWT.WRAP | SWT.CENTER);

+		label.setText("\n\n\nWhen you logoff, GNOME session manager will get stuck for 90 seconds");

+

+		// Test for deadlock with shutdown hook on regular closing

+		shell.addListener(SWT.Close, event -> {

+			System.exit(0);

+		});

+

+		shell.open ();

+

+		while (!shell.isDisposed()) {

+			if (!display.readAndDispatch ()) display.sleep ();

+		}

+

+		display.dispose ();

+	}

+}