Only run the rendezvous polling task when we have pending contacts.

bramble-core/src/main/java/org/briarproject/bramble/rendezvous/RendezvousPollerImpl.java

@@ -42,6 +42,7 @@ import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionOpenedE
 import org.briarproject.bramble.api.rendezvous.event.RendezvousPollEvent;
 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.security.GeneralSecurityException;
@@ -68,6 +69,7 @@ import static org.briarproject.bramble.api.contact.PendingContactState.ADDING_CO
 import static org.briarproject.bramble.api.contact.PendingContactState.FAILED;
 import static org.briarproject.bramble.api.contact.PendingContactState.OFFLINE;
 import static org.briarproject.bramble.api.contact.PendingContactState.WAITING_FOR_CONNECTION;
+import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
 import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNull;
 import static org.briarproject.bramble.rendezvous.RendezvousConstants.POLLING_INTERVAL_MS;
 import static org.briarproject.bramble.rendezvous.RendezvousConstants.RENDEZVOUS_TIMEOUT_MS;
@@ -102,6 +104,8 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 			new HashMap<>();
 	@Nullable
 	private KeyPair handshakeKeyPair = null;
+	@Nullable
+	private Cancellable pollTask = null;
 
 	@Inject
 	RendezvousPollerImpl(@IoExecutor Executor ioExecutor,
@@ -144,8 +148,6 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 		} catch (DbException e) {
 			throw new ServiceException(e);
 		}
-		scheduler.scheduleWithFixedDelay(this::poll, worker,
-				POLLING_INTERVAL_MS, POLLING_INTERVAL_MS, MILLISECONDS);
 	}
 
 	@EventExecutor
@@ -186,6 +188,12 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 			}
 			if (cs.numEndpoints == 0) broadcastState(p.getId(), OFFLINE);
 			else broadcastState(p.getId(), WAITING_FOR_CONNECTION);
+			if (cryptoStates.size() == 1) {
+				LOG.info("Starting poller");
+				requireNull(pollTask);
+				pollTask = scheduler.scheduleWithFixedDelay(this::poll, worker,
+						POLLING_INTERVAL_MS, POLLING_INTERVAL_MS, MILLISECONDS);
+			}
 		} catch (DbException | GeneralSecurityException e) {
 			logException(LOG, WARNING, e);
 		}
@@ -208,6 +216,7 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 	// Worker
 	@Wakeful
 	private void poll() {
+		LOG.info("Polling");
 		removeExpiredPendingContacts();
 		for (PluginState ps : pluginStates.values()) poll(ps);
 	}
@@ -234,6 +243,11 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 			RendezvousEndpoint endpoint = ps.endpoints.remove(p);
 			if (endpoint != null) tryToClose(endpoint, LOG, INFO);
 		}
+		if (cryptoStates.isEmpty()) {
+			LOG.info("Stopping poller");
+			requireNonNull(pollTask).cancel();
+			pollTask = null;
+		}
 	}
 
 	// Worker

bramble-core/src/test/java/org/briarproject/bramble/rendezvous/RendezvousPollerImplTest.java

@@ -27,6 +27,7 @@ import org.briarproject.bramble.api.rendezvous.event.RendezvousConnectionOpenedE
 import org.briarproject.bramble.api.rendezvous.event.RendezvousPollEvent;
 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.test.BrambleMockTestCase;
 import org.briarproject.bramble.test.CaptureArgumentAction;
 import org.briarproject.bramble.test.DbExpectations;
@@ -79,6 +80,7 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 			context.mock(KeyMaterialSource.class);
 	private final RendezvousEndpoint rendezvousEndpoint =
 			context.mock(RendezvousEndpoint.class);
+	private final Cancellable cancellable = context.mock(Cancellable.class);
 
 	private final Executor ioExecutor = new ImmediateExecutor();
 	private final PendingContact pendingContact = getPendingContact();
@@ -107,7 +109,7 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		long beforeExpiry = pendingContact.getTimestamp()
 				+ RENDEZVOUS_TIMEOUT_MS - 1000;
 		long afterExpiry = beforeExpiry + POLLING_INTERVAL_MS;
-		AtomicReference<Runnable> capturePollTask = new AtomicReference<>();
+		AtomicReference<Runnable> capturePollTask;
 
 		// Start the service
 		context.checking(new DbExpectations() {{
@@ -121,21 +123,17 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 			oneOf(eventBus).broadcast(with(new PredicateMatcher<>(
 					PendingContactStateChangedEvent.class, e ->
 					e.getPendingContactState() == OFFLINE)));
-			// Capture the poll task
-			oneOf(scheduler).scheduleWithFixedDelay(with(any(Runnable.class)),
-					with(any(Executor.class)), with(POLLING_INTERVAL_MS),
-					with(POLLING_INTERVAL_MS), with(MILLISECONDS));
-			will(new CaptureArgumentAction<>(capturePollTask, Runnable.class,
-					0));
 		}});
 
 		expectDeriveRendezvousKey();
+		capturePollTask = expectSchedulePolling();
 
 		rendezvousPoller.startService();
 		context.assertIsSatisfied();
 
-		// Run the poll task - pending contact expires
+		// Run the poll task - pending contact expires, polling is cancelled
 		expectPendingContactExpires(afterExpiry);
+		expectCancelPolling();
 
 		capturePollTask.get().run();
 	}
@@ -157,10 +155,6 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 			oneOf(eventBus).broadcast(with(new PredicateMatcher<>(
 					PendingContactStateChangedEvent.class, e ->
 					e.getPendingContactState() == FAILED)));
-			// Schedule the poll task
-			oneOf(scheduler).scheduleWithFixedDelay(with(any(Runnable.class)),
-					with(any(Executor.class)), with(POLLING_INTERVAL_MS),
-					with(POLLING_INTERVAL_MS), with(MILLISECONDS));
 		}});
 
 		rendezvousPoller.startService();
@@ -183,7 +177,8 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		rendezvousPoller.eventOccurred(new TransportActiveEvent(transportId));
 		context.assertIsSatisfied();
 
-		// Add the pending contact - endpoint should be created and polled
+		// Add the pending contact - endpoint should be created and polled,
+		// polling should be scheduled
 		expectAddPendingContact(beforeExpiry, WAITING_FOR_CONNECTION);
 		expectDeriveRendezvousKey();
 		expectCreateEndpoint();
@@ -200,12 +195,16 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 					any(ConnectionHandler.class)))));
 		}});
 
+		expectSchedulePolling();
+
 		rendezvousPoller.eventOccurred(
 				new PendingContactAddedEvent(pendingContact));
 		context.assertIsSatisfied();
 
-		// Remove the pending contact - endpoint should be closed
+		// Remove the pending contact - endpoint should be closed,
+		// polling should be cancelled
 		expectCloseEndpoint();
+		expectCancelPolling();
 
 		rendezvousPoller.eventOccurred(
 				new PendingContactRemovedEvent(pendingContact.getId()));
@@ -221,10 +220,10 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		long beforeExpiry = pendingContact.getTimestamp()
 				+ RENDEZVOUS_TIMEOUT_MS - 1000;
 		long afterExpiry = beforeExpiry + POLLING_INTERVAL_MS;
+		AtomicReference<Runnable> capturePollTask;
 
-		// Start the service, capturing the poll task
+		// Start the service
-		AtomicReference<Runnable> capturePollTask =
+		expectStartupWithNoPendingContacts();
-				expectStartupWithNoPendingContacts();
 
 		rendezvousPoller.startService();
 		context.assertIsSatisfied();
@@ -235,7 +234,8 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		rendezvousPoller.eventOccurred(new TransportActiveEvent(transportId));
 		context.assertIsSatisfied();
 
-		// Add the pending contact - endpoint should be created and polled
+		// Add the pending contact - endpoint should be created and polled,
+		// polling should be scheduled
 		expectAddPendingContact(beforeExpiry, WAITING_FOR_CONNECTION);
 		expectDeriveRendezvousKey();
 		expectCreateEndpoint();
@@ -252,13 +252,17 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 					any(ConnectionHandler.class)))));
 		}});
 
+		capturePollTask = expectSchedulePolling();
+
 		rendezvousPoller.eventOccurred(
 				new PendingContactAddedEvent(pendingContact));
 		context.assertIsSatisfied();
 
-		// Run the poll task - pending contact expires, endpoint is closed
+		// Run the poll task - pending contact expires, endpoint is closed,
+		// polling is cancelled
 		expectPendingContactExpires(afterExpiry);
 		expectCloseEndpoint();
+		expectCancelPolling();
 
 		capturePollTask.get().run();
 		context.assertIsSatisfied();
@@ -286,6 +290,7 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		// Add the pending contact - no endpoints should be created yet
 		expectAddPendingContact(beforeExpiry, OFFLINE);
 		expectDeriveRendezvousKey();
+		expectSchedulePolling();
 
 		rendezvousPoller.eventOccurred(
 				new PendingContactAddedEvent(pendingContact));
@@ -307,6 +312,8 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		context.assertIsSatisfied();
 
 		// Remove the pending contact - endpoint is already closed
+		expectCancelPolling();
+
 		rendezvousPoller.eventOccurred(
 				new PendingContactRemovedEvent(pendingContact.getId()));
 	}
@@ -348,8 +355,9 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		rendezvousPoller.startService();
 		context.assertIsSatisfied();
 
-		// Run the poll task - pending contact expires
+		// Run the poll task - pending contact expires, polling is cancelled
 		expectPendingContactExpires(afterExpiry);
+		expectCancelPolling();
 
 		capturePollTask.get().run();
 		context.assertIsSatisfied();
@@ -385,8 +393,9 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 				new RendezvousConnectionOpenedEvent(pendingContact.getId()));
 		context.assertIsSatisfied();
 
-		// Run the poll task - pending contact expires
+		// Run the poll task - pending contact expires, polling is cancelled
 		expectPendingContactExpires(afterExpiry);
+		expectCancelPolling();
 
 		capturePollTask.get().run();
 		context.assertIsSatisfied();
@@ -417,8 +426,9 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 				new RendezvousConnectionOpenedEvent(pendingContact.getId()));
 		context.assertIsSatisfied();
 
-		// Run the poll task - pending contact expires
+		// Run the poll task - pending contact expires, polling is cancelled
 		expectPendingContactExpires(afterExpiry);
+		expectCancelPolling();
 
 		capturePollTask.get().run();
 		context.assertIsSatisfied();
@@ -447,6 +457,8 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 		context.assertIsSatisfied();
 
 		// Pending contact is removed - no event should be broadcast
+		expectCancelPolling();
+
 		rendezvousPoller.eventOccurred(
 				new PendingContactRemovedEvent(pendingContact.getId()));
 		context.assertIsSatisfied();
@@ -456,25 +468,35 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 				pendingContact.getId(), false));
 	}
 
-	private AtomicReference<Runnable> expectStartupWithNoPendingContacts()
+	private AtomicReference<Runnable> expectSchedulePolling() {
-			throws Exception {
-		Transaction txn = new Transaction(null, true);
 		AtomicReference<Runnable> capturePollTask = new AtomicReference<>();
 
+		context.checking(new Expectations() {{
+			oneOf(scheduler).scheduleWithFixedDelay(with(any(Runnable.class)),
+					with(any(Executor.class)), with(POLLING_INTERVAL_MS),
+					with(POLLING_INTERVAL_MS), with(MILLISECONDS));
+			will(doAll(new CaptureArgumentAction<>(capturePollTask,
+					Runnable.class, 0), returnValue(cancellable)));
+		}});
+
+		return capturePollTask;
+	}
+
+	private void expectCancelPolling() {
+		context.checking(new Expectations() {{
+			oneOf(cancellable).cancel();
+		}});
+	}
+
+	private void expectStartupWithNoPendingContacts() throws Exception {
+		Transaction txn = new Transaction(null, true);
+
 		context.checking(new DbExpectations() {{
 			// Load the pending contacts
 			oneOf(db).transaction(with(true), withDbRunnable(txn));
 			oneOf(db).getPendingContacts(txn);
 			will(returnValue(emptyList()));
-			// Capture the poll task
-			oneOf(scheduler).scheduleWithFixedDelay(with(any(Runnable.class)),
-					with(any(Executor.class)), with(POLLING_INTERVAL_MS),
-					with(POLLING_INTERVAL_MS), with(MILLISECONDS));
-			will(new CaptureArgumentAction<>(capturePollTask, Runnable.class,
-					0));
 		}});
-
-		return capturePollTask;
 	}
 
 	private void expectAddPendingContact(long now,
@@ -530,7 +552,6 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 	private AtomicReference<Runnable> expectStartupWithPendingContact(long now)
 			throws Exception {
 		Transaction txn = new Transaction(null, true);
-		AtomicReference<Runnable> capturePollTask = new AtomicReference<>();
 
 		context.checking(new DbExpectations() {{
 			// Load the pending contacts
@@ -543,17 +564,10 @@ public class RendezvousPollerImplTest extends BrambleMockTestCase {
 			oneOf(eventBus).broadcast(with(new PredicateMatcher<>(
 					PendingContactStateChangedEvent.class, e ->
 					e.getPendingContactState() == OFFLINE)));
-			// Capture the poll task
-			oneOf(scheduler).scheduleWithFixedDelay(with(any(Runnable.class)),
-					with(any(Executor.class)), with(POLLING_INTERVAL_MS),
-					with(POLLING_INTERVAL_MS), with(MILLISECONDS));
-			will(new CaptureArgumentAction<>(capturePollTask, Runnable.class,
-					0));
 		}});
 
 		expectDeriveRendezvousKey();
-
+		return expectSchedulePolling();
-		return capturePollTask;
 	}
 
 	private void expectPendingContactExpires(long now) {