/*
* Aphelion
* Copyright (c) 2013 Joris van der Wel
*
* This file is part of Aphelion
*
* Aphelion is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, version 3 of the License.
*
* Aphelion is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with Aphelion. If not, see <http://www.gnu.org/licenses/>.
*
* In addition, the following supplemental terms apply, based on section 7 of
* the GNU Affero General Public License (version 3):
* a) Preservation of all legal notices and author attributions
* b) Prohibition of misrepresentation of the origin of this material, and
* modified versions are required to be marked in reasonable ways as
* different from the original version (for example by appending a copyright notice).
*
* Linking this library statically or dynamically with other modules is making a
* combined work based on this library. Thus, the terms and conditions of the
* GNU Affero General Public License cover the whole combination.
*
* As a special exception, the copyright holders of this library give you
* permission to link this library with independent modules to produce an
* executable, regardless of the license terms of these independent modules,
* and to copy and distribute the resulting executable under terms of your
* choice, provided that you also meet, for each linked independent module,
* the terms and conditions of the license of that module. An independent
* module is a module which is not derived from or based on this library.
*/
package aphelion.shared.event;
import aphelion.client.ErrorDialog;
import aphelion.shared.swissarmyknife.SwissArmyKnife;
import aphelion.shared.swissarmyknife.ThreadSafe;
import java.util.Iterator;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
*
* @author Joris
*/
public class Deadlock
{
private static final Logger log = Logger.getLogger("aphelion.eventloop.deadlock");
private final static CopyOnWriteArrayList<TickedEventLoop> eventLoops = new CopyOnWriteArrayList<>();
private static DeadlockThread thread;
private static boolean gui;
private static DeadlockListener listener;
/** If an event loop has not updated its watchdog counter for this many milliseconds, do something. */
private static final int CHECK_INTERVAL_MILLIS = 30000;
public static interface DeadlockListener
{
/** Called if a deadlock has been detect in an event loop.
* At this point the event loop is no longer monitored.
* If the deadlock is resolved by this method, it should call Deadlock.add() to
* re-add the event loop.
* If this method returns true the thread is forcefully stopped instead.
* @param eventLoop
* @param thread
* @return True if the thread should be forcefully stopped
*/
boolean deadlockDetected(TickedEventLoop eventLoop, Thread thread);
/** Called after a deadlock has been detected and the thread has been forcefully stopped.
* @param eventLoop
* @param thread
*/
void deadlockAfterStop(TickedEventLoop eventLoop, Thread thread);
}
public static interface DeadlockTicker
{
/** Update the deadlock tick count.
* Ticked event loops are monitored by a deadlock thread which watches this value.
* If this value is not updated in a long while, the application is terminated.
* Call this method to manually update this value.
*/
@ThreadSafe
void tickDeadlock();
}
public static final DeadlockTicker noopTicker = new DeadlockTicker()
{
@Override
public void tickDeadlock()
{
}
};
public static void start(boolean showGUI, DeadlockListener deadlockListener)
{
gui = showGUI;
listener = deadlockListener;
if (thread != null)
{
throw new IllegalStateException();
}
thread = new DeadlockThread();
thread.setDaemon(true);
thread.start();
}
public static void stop()
{
thread.interrupt();
thread = null;
}
@ThreadSafe
public static void add(TickedEventLoop eventLoop)
{
eventLoops.add(eventLoop);
}
@ThreadSafe
public static void remove(TickedEventLoop eventLoop)
{
eventLoops.remove(eventLoop);
}
private static class DeadlockThread extends Thread
{
@Override
public void run()
{
Iterator<TickedEventLoop> it;
TickedEventLoop eventLoop;
setName("Deadlock-" + this.getId());
while (true)
{
it = eventLoops.iterator();
while (it.hasNext())
{
eventLoop = it.next();
if (eventLoop.deadlock_tick != eventLoop.deadlock_tick_lastseen)
{
eventLoop.deadlock_tick_lastseen = eventLoop.deadlock_tick;
continue;
}
eventLoops.remove(eventLoop);
String trace = "";
Thread thread = eventLoop.myThread;
for (StackTraceElement stack : thread.getStackTrace())
{
trace += stack.toString() + "\n";
}
boolean kill = true;
if (listener != null)
{
kill = listener.deadlockDetected(eventLoop, thread);
}
if (kill)
{
log.log(Level.SEVERE, "Deadlock or infinite loop detected in thread {0}, attemping to stop ... Stack trace: \n{1}",
new Object[]
{
thread.getName(),
trace
}
);
SwissArmyKnife.logTraceOfAllThreads(log);
thread.interrupt();
try
{
Thread.sleep(1000);
}
catch (InterruptedException ex)
{
return;
}
log.log(Level.SEVERE, "Attemping stop of thread {0}", thread.getName());
thread.stop();
if (listener != null)
{
listener.deadlockAfterStop(eventLoop, thread);
}
if (gui)
{
ErrorDialog diag;
diag = new ErrorDialog();
diag.setTitle("Deadlock: " + thread.getName());
diag.setErrorText(trace);
}
}
else
{
log.log(Level.SEVERE, "Deadlock or infinite loop detected in thread {0} (no action). Stack trace: \n{1}",
new Object[] {
thread.getName(),
trace
});
}
}
try
{
Thread.sleep(CHECK_INTERVAL_MILLIS);
}
catch (InterruptedException ex)
{
return;
}
}
}
}
}