Merge branch '1759-fix-periodic-task-cancellation' into 'master'

Fix cancellation of periodic tasks, remove ticker

Closes #1759

See merge request briar/briar!1274

bramble-core/src/main/java/org/briarproject/bramble/io/TimeoutMonitorImpl.java

@@ -4,6 +4,7 @@ import org.briarproject.bramble.api.io.TimeoutMonitor;
 import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.bramble.api.system.TaskScheduler.Cancellable;
 import org.briarproject.bramble.api.system.Wakeful;
 
 import java.io.IOException;
@@ -11,7 +12,6 @@ import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.Executor;
-import java.util.concurrent.Future;
 import java.util.logging.Logger;
 
 import javax.annotation.concurrent.GuardedBy;
@@ -38,7 +38,7 @@ class TimeoutMonitorImpl implements TimeoutMonitor {
 	private final List<TimeoutInputStream> streams = new ArrayList<>();
 
 	@GuardedBy("lock")
-	private Future<?> task = null;
+	private Cancellable cancellable = null;
 
 	@Inject
 	TimeoutMonitorImpl(TaskScheduler scheduler,
@@ -55,9 +55,9 @@ class TimeoutMonitorImpl implements TimeoutMonitor {
 				timeoutMs, this::removeStream);
 		synchronized (lock) {
 			if (streams.isEmpty()) {
-				task = scheduler.scheduleWithFixedDelay(this::checkTimeouts,
-						ioExecutor, CHECK_INTERVAL_MS, CHECK_INTERVAL_MS,
-						MILLISECONDS);
+				cancellable = scheduler.scheduleWithFixedDelay(
+						this::checkTimeouts, ioExecutor, CHECK_INTERVAL_MS,
+						CHECK_INTERVAL_MS, MILLISECONDS);
 			}
 			streams.add(stream);
 		}
@@ -65,14 +65,17 @@ class TimeoutMonitorImpl implements TimeoutMonitor {
 	}
 
 	private void removeStream(TimeoutInputStream stream) {
-		Future<?> toCancel = null;
+		Cancellable toCancel = null;
 		synchronized (lock) {
 			if (streams.remove(stream) && streams.isEmpty()) {
-				toCancel = task;
-				task = null;
+				toCancel = cancellable;
+				cancellable = null;
 			}
 		}
-		if (toCancel != null) toCancel.cancel(false);
+		if (toCancel != null) {
+			LOG.info("Cancelling timeout monitor task");
+			toCancel.cancel();
+		}
 	}
 
 	@IoExecutor

bramble-core/src/main/java/org/briarproject/bramble/plugin/PollerImpl.java

@@ -27,6 +27,7 @@ import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.properties.TransportPropertyManager;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.bramble.api.system.TaskScheduler.Cancellable;
 import org.briarproject.bramble.api.system.Wakeful;
 import org.briarproject.bramble.api.system.WakefulIoExecutor;
 
@@ -37,7 +38,6 @@ import java.util.HashMap;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.concurrent.Executor;
-import java.util.concurrent.Future;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
 import java.util.logging.Logger;
@@ -191,11 +191,11 @@ class PollerImpl implements Poller, EventListener {
 			if (scheduled == null || due < scheduled.task.due) {
 				// If a later task exists, cancel it. If it's already started
 				// it will abort safely when it finds it's been replaced
-				if (scheduled != null) scheduled.future.cancel(false);
+				if (scheduled != null) scheduled.cancellable.cancel();
 				PollTask task = new PollTask(p, due, randomiseNext);
-				Future<?> future = scheduler.schedule(task, ioExecutor, delay,
-						MILLISECONDS);
-				tasks.put(t, new ScheduledPollTask(task, future));
+				Cancellable cancellable = scheduler.schedule(task, ioExecutor,
+						delay, MILLISECONDS);
+				tasks.put(t, new ScheduledPollTask(task, cancellable));
 			}
 		} finally {
 			lock.unlock();
@@ -206,7 +206,7 @@ class PollerImpl implements Poller, EventListener {
 		lock.lock();
 		try {
 			ScheduledPollTask scheduled = tasks.remove(t);
-			if (scheduled != null) scheduled.future.cancel(false);
+			if (scheduled != null) scheduled.cancellable.cancel();
 		} finally {
 			lock.unlock();
 		}
@@ -237,11 +237,11 @@ class PollerImpl implements Poller, EventListener {
 	private class ScheduledPollTask {
 
 		private final PollTask task;
-		private final Future<?> future;
+		private final Cancellable cancellable;
 
-		private ScheduledPollTask(PollTask task, Future<?> future) {
+		private ScheduledPollTask(PollTask task, Cancellable cancellable) {
 			this.task = task;
-			this.future = future;
+			this.cancellable = cancellable;
 		}
 	}
 

bramble-core/src/main/java/org/briarproject/bramble/system/TaskSchedulerImpl.java

@@ -4,8 +4,8 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.system.TaskScheduler;
 
 import java.util.concurrent.Executor;
-import java.util.concurrent.Future;
 import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.TimeUnit;
 
 import javax.annotation.concurrent.ThreadSafe;
@@ -24,17 +24,20 @@ class TaskSchedulerImpl implements TaskScheduler {
 	}
 
 	@Override
-	public Future<?> schedule(Runnable task, Executor executor, long delay,
+	public Cancellable schedule(Runnable task, Executor executor, long delay,
 			TimeUnit unit) {
 		Runnable execute = () -> executor.execute(task);
-		return scheduledExecutorService.schedule(execute, delay, unit);
+		ScheduledFuture<?> future =
+				scheduledExecutorService.schedule(execute, delay, unit);
+		return () -> future.cancel(false);
 	}
 
 	@Override
-	public Future<?> scheduleWithFixedDelay(Runnable task, Executor executor,
+	public Cancellable scheduleWithFixedDelay(Runnable task, Executor executor,
 			long delay, long interval, TimeUnit unit) {
 		Runnable execute = () -> executor.execute(task);
-		return scheduledExecutorService.scheduleWithFixedDelay(execute, delay,
-				interval, unit);
+		ScheduledFuture<?> future = scheduledExecutorService.
+				scheduleWithFixedDelay(execute, delay, interval, unit);
+		return () -> future.cancel(false);
 	}
 }