Merge branch '1142-wakeful-lifecycle' into 'master'

Hold a wake lock during app startup and shutdown

See merge request briar/briar!1271

bramble-android/src/main/java/org/briarproject/bramble/api/system/AndroidWakeLockManager.java

@@ -24,4 +24,15 @@ public interface AndroidWakeLockManager {
 	 * thrown while submitting or running the task.
 	 */
 	void executeWakefully(Runnable r, Executor executor, String tag);
+
+	/**
+	 * Starts a dedicated thread to run the given task asynchronously. A wake
+	 * lock is acquired before starting the thread and released when the task
+	 * completes, or if an exception is thrown while starting the thread or
+	 * running the task.
+	 * <p>
+	 * This method should only be used for lifecycle management tasks that
+	 * can't be run on an executor.
+	 */
+	void executeWakefully(Runnable r, String tag);
 }

bramble-android/src/main/java/org/briarproject/bramble/system/AndroidWakeLockManagerImpl.java

@@ -86,6 +86,24 @@ class AndroidWakeLockManagerImpl implements AndroidWakeLockManager {
 		}
 	}
 
+	@Override
+	public void executeWakefully(Runnable r, String tag) {
+		AndroidWakeLock wakeLock = createWakeLock(tag);
+		wakeLock.acquire();
+		try {
+			new Thread(() -> {
+				try {
+					r.run();
+				} finally {
+					wakeLock.release();
+				}
+			}).start();
+		} catch (Exception e) {
+			wakeLock.release();
+			throw e;
+		}
+	}
+
 	private String getWakeLockTag(Context ctx) {
 		PackageManager pm = ctx.getPackageManager();
 		for (PackageInfo info : pm.getInstalledPackages(0)) {

bramble-api/src/main/java/org/briarproject/bramble/api/lifecycle/LifecycleManager.java

@@ -5,6 +5,7 @@ import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.system.Wakeful;
 
 import java.util.concurrent.ExecutorService;
 
@@ -65,6 +66,7 @@ public interface LifecycleManager {
 	 * Opens the {@link DatabaseComponent} using the given key and starts any
 	 * registered {@link Service Services}.
 	 */
+	@Wakeful
 	StartResult startServices(SecretKey dbKey);
 
 	/**
@@ -72,6 +74,7 @@ public interface LifecycleManager {
 	 * registered {@link ExecutorService ExecutorServices}, and closes the
 	 * {@link DatabaseComponent}.
 	 */
+	@Wakeful
 	void stopServices();
 
 	/**
@@ -104,6 +107,7 @@ public interface LifecycleManager {
 		 *
 		 * @param txn A read-write transaction
 		 */
+		@Wakeful
 		void onDatabaseOpened(Transaction txn) throws DbException;
 	}
 }

bramble-api/src/main/java/org/briarproject/bramble/api/lifecycle/Service.java

@@ -1,16 +1,20 @@
 package org.briarproject.bramble.api.lifecycle;
 
+import org.briarproject.bramble.api.system.Wakeful;
+
 public interface Service {
 
 	/**
-	 * Starts the service.This method must not be called concurrently with
+	 * Starts the service. This method must not be called concurrently with
 	 * {@link #stopService()}.
 	 */
+	@Wakeful
 	void startService() throws ServiceException;
 
 	/**
 	 * Stops the service. This method must not be called concurrently with
 	 * {@link #startService()}.
 	 */
+	@Wakeful
 	void stopService() throws ServiceException;
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/Plugin.java

@@ -4,6 +4,7 @@ import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.settings.SettingsManager;
+import org.briarproject.bramble.api.system.Wakeful;
 
 import java.util.Collection;
 
@@ -70,11 +71,13 @@ public interface Plugin {
 	/**
 	 * Starts the plugin.
 	 */
+	@Wakeful
 	void start() throws PluginException;
 
 	/**
 	 * Stops the plugin.
 	 */
+	@Wakeful
 	void stop() throws PluginException;
 
 	/**
@@ -106,6 +109,7 @@ public interface Plugin {
 	 * Attempts to create connections using the given transport properties,
 	 * passing any created connections to the corresponding handlers.
 	 */
+	@Wakeful
 	void poll(Collection<Pair<TransportProperties, ConnectionHandler>>
 			properties);
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/duplex/DuplexPlugin.java

@@ -8,6 +8,7 @@ import org.briarproject.bramble.api.plugin.Plugin;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.rendezvous.KeyMaterialSource;
 import org.briarproject.bramble.api.rendezvous.RendezvousEndpoint;
+import org.briarproject.bramble.api.system.Wakeful;
 
 import javax.annotation.Nullable;
 
@@ -21,6 +22,7 @@ public interface DuplexPlugin extends Plugin {
 	 * Attempts to create and return a connection using the given transport
 	 * properties. Returns null if a connection cannot be created.
 	 */
+	@Wakeful
 	@Nullable
 	DuplexTransportConnection createConnection(TransportProperties p);
 

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/simplex/SimplexPlugin.java

@@ -5,6 +5,7 @@ import org.briarproject.bramble.api.plugin.Plugin;
 import org.briarproject.bramble.api.plugin.TransportConnectionReader;
 import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
 import org.briarproject.bramble.api.properties.TransportProperties;
+import org.briarproject.bramble.api.system.Wakeful;
 
 import javax.annotation.Nullable;
 
@@ -18,6 +19,7 @@ public interface SimplexPlugin extends Plugin {
 	 * Attempts to create and return a reader for the given transport
 	 * properties. Returns null if a reader cannot be created.
 	 */
+	@Wakeful
 	@Nullable
 	TransportConnectionReader createReader(TransportProperties p);
 
@@ -25,6 +27,7 @@ public interface SimplexPlugin extends Plugin {
 	 * Attempts to create and return a writer for the given transport
 	 * properties. Returns null if a writer cannot be created.
 	 */
+	@Wakeful
 	@Nullable
 	TransportConnectionWriter createWriter(TransportProperties p);
 }

bramble-api/src/main/java/org/briarproject/bramble/api/system/TaskScheduler.java

@@ -14,6 +14,9 @@ public interface TaskScheduler {
 
 	/**
 	 * Submits the given task to the given executor after the given delay.
+	 * <p>
+	 * If the platform supports wake locks, a wake lock will be held while
+	 * submitting and running the task.
 	 */
 	Future<?> schedule(Runnable task, Executor executor, long delay,
 			TimeUnit unit);
@@ -22,6 +25,9 @@ public interface TaskScheduler {
 	 * Submits the given task to the given executor after the given delay,
 	 * and then repeatedly with the given interval between executions
 	 * (measured from the end of one execution to the beginning of the next).
+	 * <p>
+	 * If the platform supports wake locks, a wake lock will be held while
+	 * submitting and running the task.
 	 */
 	Future<?> scheduleWithFixedDelay(Runnable task, Executor executor,
 			long delay, long interval, TimeUnit unit);

bramble-api/src/main/java/org/briarproject/bramble/api/system/Wakeful.java

@@ -0,0 +1,19 @@
+package org.briarproject.bramble.api.system;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.Target;
+
+import javax.inject.Qualifier;
+
+import static java.lang.annotation.ElementType.METHOD;
+import static java.lang.annotation.RetentionPolicy.RUNTIME;
+
+/**
+ * Annotation for methods that must be called while holding a wake lock, if
+ * the platform supports wake locks.
+ */
+@Qualifier
+@Target(METHOD)
+@Retention(RUNTIME)
+public @interface Wakeful {
+}

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.Wakeful;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -75,6 +76,7 @@ class TimeoutMonitorImpl implements TimeoutMonitor {
 	}
 
 	@IoExecutor
+	@Wakeful
 	private void checkTimeouts() {
 		List<TimeoutInputStream> snapshot;
 		synchronized (lock) {

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

@@ -29,6 +29,7 @@ import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.properties.TransportPropertyManager;
 import org.briarproject.bramble.api.settings.Settings;
 import org.briarproject.bramble.api.settings.SettingsManager;
+import org.briarproject.bramble.api.system.WakefulIoExecutor;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -64,7 +65,7 @@ class PluginManagerImpl implements PluginManager, Service {
 	private static final Logger LOG =
 			getLogger(PluginManagerImpl.class.getName());
 
-	private final Executor ioExecutor;
+	private final Executor ioExecutor, wakefulIoExecutor;
 	private final EventBus eventBus;
 	private final PluginConfig pluginConfig;
 	private final ConnectionManager connectionManager;
@@ -77,11 +78,15 @@ class PluginManagerImpl implements PluginManager, Service {
 	private final AtomicBoolean used = new AtomicBoolean(false);
 
 	@Inject
-	PluginManagerImpl(@IoExecutor Executor ioExecutor, EventBus eventBus,
-			PluginConfig pluginConfig, ConnectionManager connectionManager,
+	PluginManagerImpl(@IoExecutor Executor ioExecutor,
+			@WakefulIoExecutor Executor wakefulIoExecutor,
+			EventBus eventBus,
+			PluginConfig pluginConfig,
+			ConnectionManager connectionManager,
 			SettingsManager settingsManager,
 			TransportPropertyManager transportPropertyManager) {
 		this.ioExecutor = ioExecutor;
+		this.wakefulIoExecutor = wakefulIoExecutor;
 		this.eventBus = eventBus;
 		this.pluginConfig = pluginConfig;
 		this.connectionManager = connectionManager;
@@ -109,7 +114,7 @@ class PluginManagerImpl implements PluginManager, Service {
 				simplexPlugins.add(s);
 				CountDownLatch startLatch = new CountDownLatch(1);
 				startLatches.put(t, startLatch);
-				ioExecutor.execute(new PluginStarter(s, startLatch));
+				wakefulIoExecutor.execute(new PluginStarter(s, startLatch));
 			}
 		}
 		// Instantiate the duplex plugins and start them asynchronously
@@ -125,7 +130,7 @@ class PluginManagerImpl implements PluginManager, Service {
 				duplexPlugins.add(d);
 				CountDownLatch startLatch = new CountDownLatch(1);
 				startLatches.put(t, startLatch);
-				ioExecutor.execute(new PluginStarter(d, startLatch));
+				wakefulIoExecutor.execute(new PluginStarter(d, startLatch));
 			}
 		}
 	}
@@ -137,12 +142,16 @@ class PluginManagerImpl implements PluginManager, Service {
 		LOG.info("Stopping simplex plugins");
 		for (SimplexPlugin s : simplexPlugins) {
 			CountDownLatch startLatch = startLatches.get(s.getId());
+			// Don't need the wakeful executor here as we wait for the plugin
+			// to stop before returning
 			ioExecutor.execute(new PluginStopper(s, startLatch, stopLatch));
 		}
 		// Stop the duplex plugins
 		LOG.info("Stopping duplex plugins");
 		for (DuplexPlugin d : duplexPlugins) {
 			CountDownLatch startLatch = startLatches.get(d.getId());
+			// Don't need the wakeful executor here as we wait for the plugin
+			// to stop before returning
 			ioExecutor.execute(new PluginStopper(d, startLatch, stopLatch));
 		}
 		// Wait for all the plugins to stop
@@ -205,7 +214,7 @@ class PluginManagerImpl implements PluginManager, Service {
 		}
 	}
 
-	private class PluginStarter implements Runnable {
+	private static class PluginStarter implements Runnable {
 
 		private final Plugin plugin;
 		private final CountDownLatch startLatch;
@@ -235,7 +244,7 @@ class PluginManagerImpl implements PluginManager, Service {
 		}
 	}
 
-	private class PluginStopper implements Runnable {
+	private static class PluginStopper implements Runnable {
 
 		private final Plugin plugin;
 		private final CountDownLatch startLatch, stopLatch;

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.Wakeful;
 import org.briarproject.bramble.api.system.WakefulIoExecutor;
 
 import java.security.SecureRandom;
@@ -57,7 +58,7 @@ class PollerImpl implements Poller, EventListener {
 
 	private static final Logger LOG = getLogger(PollerImpl.class.getName());
 
-	private final Executor wakefulIoExecutor;
+	private final Executor ioExecutor, wakefulIoExecutor;
 	private final TaskScheduler scheduler;
 	private final ConnectionManager connectionManager;
 	private final ConnectionRegistry connectionRegistry;
@@ -70,7 +71,8 @@ class PollerImpl implements Poller, EventListener {
 	private final Map<TransportId, ScheduledPollTask> tasks;
 
 	@Inject
-	PollerImpl(@WakefulIoExecutor Executor wakefulIoExecutor,
+	PollerImpl(@IoExecutor Executor ioExecutor,
+			@WakefulIoExecutor Executor wakefulIoExecutor,
 			TaskScheduler scheduler,
 			ConnectionManager connectionManager,
 			ConnectionRegistry connectionRegistry,
@@ -78,6 +80,7 @@ class PollerImpl implements Poller, EventListener {
 			TransportPropertyManager transportPropertyManager,
 			SecureRandom random,
 			Clock clock) {
+		this.ioExecutor = ioExecutor;
 		this.wakefulIoExecutor = wakefulIoExecutor;
 		this.scheduler = scheduler;
 		this.connectionManager = connectionManager;
@@ -190,8 +193,8 @@ class PollerImpl implements Poller, EventListener {
 				// it will abort safely when it finds it's been replaced
 				if (scheduled != null) scheduled.future.cancel(false);
 				PollTask task = new PollTask(p, due, randomiseNext);
-				Future<?> future = scheduler.schedule(task, wakefulIoExecutor,
-						delay, MILLISECONDS);
+				Future<?> future = scheduler.schedule(task, ioExecutor, delay,
+						MILLISECONDS);
 				tasks.put(t, new ScheduledPollTask(task, future));
 			}
 		} finally {
@@ -256,6 +259,7 @@ class PollerImpl implements Poller, EventListener {
 
 		@Override
 		@IoExecutor
+		@Wakeful
 		public void run() {
 			lock.lock();
 			try {

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.Wakeful;
 
 import java.security.GeneralSecurityException;
 import java.util.ArrayList;
@@ -205,6 +206,7 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 	}
 
 	// Worker
+	@Wakeful
 	private void poll() {
 		removeExpiredPendingContacts();
 		for (PluginState ps : pluginStates.values()) poll(ps);
@@ -235,6 +237,7 @@ class RendezvousPollerImpl implements RendezvousPoller, Service, EventListener {
 	}
 
 	// Worker
+	@Wakeful
 	private void poll(PluginState ps) {
 		if (ps.endpoints.isEmpty()) return;
 		TransportId t = ps.plugin.getId();

bramble-core/src/main/java/org/briarproject/bramble/transport/TransportKeyManagerImpl.java

@@ -13,6 +13,7 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.bramble.api.system.Wakeful;
 import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.StreamContext;
 import org.briarproject.bramble.api.transport.TransportKeySet;
@@ -203,6 +204,7 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 	}
 
 	@DatabaseExecutor
+	@Wakeful
 	private void updateKeys() {
 		try {
 			db.transaction(false, this::updateKeys);
@@ -441,6 +443,8 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 		}
 	}
 
+	@DatabaseExecutor
+	@Wakeful
 	private void updateKeys(Transaction txn) throws DbException {
 		long now = clock.currentTimeMillis();
 		lock.lock();

bramble-core/src/test/java/org/briarproject/bramble/plugin/PluginManagerImplTest.java

@@ -109,8 +109,8 @@ public class PluginManagerImplTest extends BrambleTestCase {
 			oneOf(duplexPlugin).stop();
 		}});
 
-		PluginManagerImpl p = new PluginManagerImpl(ioExecutor, eventBus,
-				pluginConfig, connectionManager, settingsManager,
+		PluginManagerImpl p = new PluginManagerImpl(ioExecutor, ioExecutor,
+				eventBus, pluginConfig, connectionManager, settingsManager,
 				transportPropertyManager);
 
 		// Two plugins should be started and stopped

bramble-core/src/test/java/org/briarproject/bramble/plugin/PollerImplTest.java

@@ -58,6 +58,7 @@ public class PollerImplTest extends BrambleMockTestCase {
 	private final Future<?> future = context.mock(Future.class);
 	private final SecureRandom random;
 
+	private final Executor ioExecutor = new ImmediateExecutor();
 	private final Executor wakefulIoExecutor = new ImmediateExecutor();
 	private final TransportId transportId = getTransportId();
 	private final ContactId contactId = getContactId();
@@ -74,9 +75,9 @@ public class PollerImplTest extends BrambleMockTestCase {
 
 	@Before
 	public void setUp() {
-		poller = new PollerImpl(wakefulIoExecutor, scheduler, connectionManager,
-				connectionRegistry, pluginManager, transportPropertyManager,
-				random, clock);
+		poller = new PollerImpl(ioExecutor, wakefulIoExecutor, scheduler,
+				connectionManager, connectionRegistry, pluginManager,
+				transportPropertyManager, random, clock);
 	}
 
 	@Test
@@ -234,7 +235,7 @@ public class PollerImplTest extends BrambleMockTestCase {
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with(wakefulIoExecutor), with((long) pollingInterval),
+					with(ioExecutor), with((long) pollingInterval),
 					with(MILLISECONDS));
 			will(returnValue(future));
 		}});
@@ -263,7 +264,7 @@ public class PollerImplTest extends BrambleMockTestCase {
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with(wakefulIoExecutor), with((long) pollingInterval),
+					with(ioExecutor), with((long) pollingInterval),
 					with(MILLISECONDS));
 			will(returnValue(future));
 			// Second event
@@ -306,7 +307,7 @@ public class PollerImplTest extends BrambleMockTestCase {
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with(wakefulIoExecutor), with((long) pollingInterval),
+					with(ioExecutor), with((long) pollingInterval),
 					with(MILLISECONDS));
 			will(returnValue(future));
 			// Second event
@@ -323,7 +324,7 @@ public class PollerImplTest extends BrambleMockTestCase {
 			will(returnValue(now + 1));
 			oneOf(future).cancel(false);
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with(wakefulIoExecutor), with((long) pollingInterval - 2),
+					with(ioExecutor), with((long) pollingInterval - 2),
 					with(MILLISECONDS));
 		}});
 
@@ -350,7 +351,7 @@ public class PollerImplTest extends BrambleMockTestCase {
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with(wakefulIoExecutor), with(0L), with(MILLISECONDS));
+					with(ioExecutor), with(0L), with(MILLISECONDS));
 			will(returnValue(future));
 			will(new RunAction());
 			// Running the polling task schedules the next polling task
@@ -361,7 +362,7 @@ public class PollerImplTest extends BrambleMockTestCase {
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with(wakefulIoExecutor), with((long) (pollingInterval * 0.5)),
+					with(ioExecutor), with((long) (pollingInterval * 0.5)),
 					with(MILLISECONDS));
 			will(returnValue(future));
 			// Get the transport properties and connected contacts
@@ -394,7 +395,7 @@ public class PollerImplTest extends BrambleMockTestCase {
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with(wakefulIoExecutor), with(0L), with(MILLISECONDS));
+					with(ioExecutor), with(0L), with(MILLISECONDS));
 			will(returnValue(future));
 			will(new RunAction());
 			// Running the polling task schedules the next polling task
@@ -405,7 +406,7 @@ public class PollerImplTest extends BrambleMockTestCase {
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with(wakefulIoExecutor), with((long) (pollingInterval * 0.5)),
+					with(ioExecutor), with((long) (pollingInterval * 0.5)),
 					with(MILLISECONDS));
 			will(returnValue(future));
 			// Get the transport properties and connected contacts
@@ -436,7 +437,7 @@ public class PollerImplTest extends BrambleMockTestCase {
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with(wakefulIoExecutor), with(0L), with(MILLISECONDS));
+					with(ioExecutor), with(0L), with(MILLISECONDS));
 			will(returnValue(future));
 			// The plugin is deactivated before the task runs - cancel the task
 			oneOf(future).cancel(false);
@@ -460,7 +461,7 @@ public class PollerImplTest extends BrambleMockTestCase {
 			oneOf(clock).currentTimeMillis();
 			will(returnValue(now));
 			oneOf(scheduler).schedule(with(any(Runnable.class)),
-					with(wakefulIoExecutor), with((long) pollingInterval),
+					with(ioExecutor), with((long) pollingInterval),
 					with(MILLISECONDS));
 			will(returnValue(future));
 		}});

briar-android/src/main/java/org/briarproject/briar/android/AndroidComponent.java

@@ -24,6 +24,7 @@ import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.plugin.PluginManager;
 import org.briarproject.bramble.api.settings.SettingsManager;
 import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.bramble.api.system.AndroidWakeLockManager;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.LocationUtils;
 import org.briarproject.bramble.plugin.tor.CircumventionProvider;
@@ -166,6 +167,8 @@ public interface AndroidComponent
 
 	FeatureFlags featureFlags();
 
+	AndroidWakeLockManager wakeLockManager();
+
 	void inject(SignInReminderReceiver briarService);
 
 	void inject(BriarService briarService);

briar-android/src/main/java/org/briarproject/briar/android/BriarService.java

@@ -19,6 +19,7 @@ import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager.StartResult;
 import org.briarproject.bramble.api.system.AndroidExecutor;
+import org.briarproject.bramble.api.system.AndroidWakeLockManager;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.logout.HideUiActivity;
 import org.briarproject.briar.api.android.AndroidNotificationManager;
@@ -48,6 +49,7 @@ import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.StartResult.ALREADY_RUNNING;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.StartResult.SUCCESS;
+import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
 import static org.briarproject.briar.android.BriarApplication.ENTRY_ACTIVITY;
 import static org.briarproject.briar.api.android.AndroidNotificationManager.FAILURE_CHANNEL_ID;
 import static org.briarproject.briar.api.android.AndroidNotificationManager.FAILURE_NOTIFICATION_ID;
@@ -80,6 +82,8 @@ public class BriarService extends Service {
 	AccountManager accountManager;
 	@Inject
 	LockManager lockManager;
+	@Inject
+	AndroidWakeLockManager wakeLockManager;
 
 	// Fields that are accessed from background threads must be volatile
 	@Inject
@@ -108,54 +112,57 @@ public class BriarService extends Service {
 			return;
 		}
 
-		// Create notification channels
-		if (SDK_INT >= 26) {
-			NotificationManager nm = (NotificationManager)
-					getSystemService(NOTIFICATION_SERVICE);
-			NotificationChannel ongoingChannel = new NotificationChannel(
-					ONGOING_CHANNEL_ID,
-					getString(R.string.ongoing_notification_title),
-					IMPORTANCE_NONE);
-			ongoingChannel.setLockscreenVisibility(VISIBILITY_SECRET);
-			nm.createNotificationChannel(ongoingChannel);
-			NotificationChannel failureChannel = new NotificationChannel(
-					FAILURE_CHANNEL_ID,
-					getString(R.string.startup_failed_notification_title),
-					IMPORTANCE_DEFAULT);
-			failureChannel.setLockscreenVisibility(VISIBILITY_SECRET);
-			nm.createNotificationChannel(failureChannel);
-		}
-		Notification foregroundNotification =
-				notificationManager.getForegroundNotification();
-		startForeground(ONGOING_NOTIFICATION_ID, foregroundNotification);
-		// Start the services in a background thread
-		new Thread(() -> {
-			StartResult result = lifecycleManager.startServices(dbKey);
-			if (result == SUCCESS) {
-				started = true;
-			} else if (result == ALREADY_RUNNING) {
-				LOG.info("Already running");
-				stopSelf();
-			} else {
-				if (LOG.isLoggable(WARNING))
-					LOG.warning("Startup failed: " + result);
-				showStartupFailureNotification(result);
-				stopSelf();
+		// Hold a wake lock during startup
+		wakeLockManager.runWakefully(() -> {
+			// Create notification channels
+			if (SDK_INT >= 26) {
+				NotificationManager nm = (NotificationManager)
+						requireNonNull(getSystemService(NOTIFICATION_SERVICE));
+				NotificationChannel ongoingChannel = new NotificationChannel(
+						ONGOING_CHANNEL_ID,
+						getString(R.string.ongoing_notification_title),
+						IMPORTANCE_NONE);
+				ongoingChannel.setLockscreenVisibility(VISIBILITY_SECRET);
+				nm.createNotificationChannel(ongoingChannel);
+				NotificationChannel failureChannel = new NotificationChannel(
+						FAILURE_CHANNEL_ID,
+						getString(R.string.startup_failed_notification_title),
+						IMPORTANCE_DEFAULT);
+				failureChannel.setLockscreenVisibility(VISIBILITY_SECRET);
+				nm.createNotificationChannel(failureChannel);
 			}
-		}).start();
-		// Register for device shutdown broadcasts
-		receiver = new BroadcastReceiver() {
-			@Override
-			public void onReceive(Context context, Intent intent) {
-				LOG.info("Device is shutting down");
-				shutdownFromBackground();
-			}
-		};
-		IntentFilter filter = new IntentFilter();
-		filter.addAction(ACTION_SHUTDOWN);
-		filter.addAction("android.intent.action.QUICKBOOT_POWEROFF");
-		filter.addAction("com.htc.intent.action.QUICKBOOT_POWEROFF");
-		registerReceiver(receiver, filter);
+			Notification foregroundNotification =
+					notificationManager.getForegroundNotification();
+			startForeground(ONGOING_NOTIFICATION_ID, foregroundNotification);
+			// Start the services in a background thread
+			wakeLockManager.executeWakefully(() -> {
+				StartResult result = lifecycleManager.startServices(dbKey);
+				if (result == SUCCESS) {
+					started = true;
+				} else if (result == ALREADY_RUNNING) {
+					LOG.info("Already running");
+					stopSelf();
+				} else {
+					if (LOG.isLoggable(WARNING))
+						LOG.warning("Startup failed: " + result);
+					showStartupFailureNotification(result);
+					stopSelf();
+				}
+			}, "LifecycleStartup");
+			// Register for device shutdown broadcasts
+			receiver = new BroadcastReceiver() {
+				@Override
+				public void onReceive(Context context, Intent intent) {
+					LOG.info("Device is shutting down");
+					shutdownFromBackground();
+				}
+			};
+			IntentFilter filter = new IntentFilter();
+			filter.addAction(ACTION_SHUTDOWN);
+			filter.addAction("android.intent.action.QUICKBOOT_POWEROFF");
+			filter.addAction("com.htc.intent.action.QUICKBOOT_POWEROFF");
+			registerReceiver(receiver, filter);
+		}, "LifecycleStartup");
 	}
 
 	@Override
@@ -179,8 +186,8 @@ public class BriarService extends Service {
 			i.putExtra(EXTRA_NOTIFICATION_ID, FAILURE_NOTIFICATION_ID);
 			b.setContentIntent(PendingIntent.getActivity(BriarService.this,
 					0, i, FLAG_UPDATE_CURRENT));
-			Object o = getSystemService(NOTIFICATION_SERVICE);
-			NotificationManager nm = (NotificationManager) o;
+			NotificationManager nm = (NotificationManager)
+					requireNonNull(getSystemService(NOTIFICATION_SERVICE));
 			nm.notify(FAILURE_NOTIFICATION_ID, b.build());
 			// Bring the dashboard to the front to clear the back stack
 			i = new Intent(BriarService.this, ENTRY_ACTIVITY);
@@ -205,14 +212,17 @@ public class BriarService extends Service {
 
 	@Override
 	public void onDestroy() {
-		super.onDestroy();
-		LOG.info("Destroyed");
-		stopForeground(true);
-		if (receiver != null) unregisterReceiver(receiver);
-		// Stop the services in a background thread
-		new Thread(() -> {
-			if (started) lifecycleManager.stopServices();
-		}).start();
+		// Hold a wake lock during shutdown
+		wakeLockManager.runWakefully(() -> {
+			super.onDestroy();
+			LOG.info("Destroyed");
+			stopForeground(true);
+			if (receiver != null) unregisterReceiver(receiver);
+			// Stop the services in a background thread
+			wakeLockManager.executeWakefully(() -> {
+				if (started) lifecycleManager.stopServices();
+			}, "LifecycleShutdown");
+		}, "LifecycleShutdown");
 	}
 
 	@Override
@@ -257,20 +267,23 @@ public class BriarService extends Service {
 	}
 
 	private void shutdownFromBackground() {
-		// Stop the service
-		stopSelf();
-		// Hide the UI
-		hideUi();
-		// Wait for shutdown to complete, then exit
-		new Thread(() -> {
-			try {
-				if (started) lifecycleManager.waitForShutdown();
-			} catch (InterruptedException e) {
-				LOG.info("Interrupted while waiting for shutdown");
-			}
-			LOG.info("Exiting");
-			System.exit(0);
-		}).start();
+		// Hold a wake lock during shutdown
+		wakeLockManager.runWakefully(() -> {
+			// Stop the service
+			stopSelf();
+			// Hide the UI
+			hideUi();
+			// Wait for shutdown to complete, then exit
+			wakeLockManager.executeWakefully(() -> {
+				try {
+					if (started) lifecycleManager.waitForShutdown();
+				} catch (InterruptedException e) {
+					LOG.info("Interrupted while waiting for shutdown");
+				}
+				LOG.info("Exiting");
+				System.exit(0);
+			}, "BackgroundShutdown");
+		}, "BackgroundShutdown");
 	}
 
 	/**

briar-android/src/main/java/org/briarproject/briar/android/activity/ActivityComponent.java

@@ -82,13 +82,19 @@ import org.briarproject.briar.android.test.TestDataActivity;
 import dagger.Component;
 
 @ActivityScope
-@Component(
-		modules = {ActivityModule.class, ForumModule.class, SharingModule.class,
-				BlogModule.class, ContactModule.class, GroupListModule.class,
-				CreateGroupModule.class, GroupInvitationModule.class,
-				GroupConversationModule.class, GroupMemberModule.class,
-				GroupRevealModule.class},
-		dependencies = AndroidComponent.class)
+@Component(modules = {
+		ActivityModule.class,
+		BlogModule.class,
+		ContactModule.class,
+		CreateGroupModule.class,
+		ForumModule.class,
+		GroupInvitationModule.class,
+		GroupConversationModule.class,
+		GroupListModule.class,
+		GroupMemberModule.class,
+		GroupRevealModule.class,
+		SharingModule.class
+}, dependencies = AndroidComponent.class)
 public interface ActivityComponent {
 
 	Activity activity();

briar-android/src/main/java/org/briarproject/briar/android/activity/BriarActivity.java

@@ -7,6 +7,8 @@ import android.widget.CheckBox;
 
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.bramble.api.system.AndroidWakeLockManager;
+import org.briarproject.bramble.api.system.Wakeful;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.account.UnlockActivity;
 import org.briarproject.briar.android.controller.BriarController;
@@ -32,6 +34,7 @@ import static android.content.Intent.FLAG_ACTIVITY_NEW_TASK;
 import static android.content.Intent.FLAG_ACTIVITY_NO_ANIMATION;
 import static android.os.Build.VERSION.SDK_INT;
 import static java.util.logging.Level.INFO;
+import static java.util.logging.Logger.getLogger;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_DOZE_WHITELISTING;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_PASSWORD;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_UNLOCK;
@@ -47,7 +50,7 @@ public abstract class BriarActivity extends BaseActivity {
 	public static final String GROUP_NAME = "briar.GROUP_NAME";
 
 	private static final Logger LOG =
-			Logger.getLogger(BriarActivity.class.getName());
+			getLogger(BriarActivity.class.getName());
 
 	@Inject
 	BriarController briarController;
@@ -56,6 +59,8 @@ public abstract class BriarActivity extends BaseActivity {
 	DbController dbController;
 	@Inject
 	protected LockManager lockManager;
+	@Inject
+	AndroidWakeLockManager wakeLockManager;
 
 	@Override
 	public void onStart() {
@@ -130,6 +135,7 @@ public abstract class BriarActivity extends BaseActivity {
 
 	/**
 	 * Sets the transition animations.
+	 *
 	 * @param enterTransition used to move views into initial positions
 	 * @param exitTransition used to move views out when starting a <b>new</b> activity.
 	 * @param returnTransition used when window is closing, because the activity is finishing.
@@ -197,22 +203,30 @@ public abstract class BriarActivity extends BaseActivity {
 
 	protected void signOut(boolean removeFromRecentApps,
 			boolean deleteAccount) {
-		if (briarController.accountSignedIn()) {
-			// Don't use UiResultHandler because we want the result even if
-			// this activity has been destroyed
-			briarController.signOut(result -> runOnUiThread(
-					() -> exit(removeFromRecentApps)), deleteAccount);
-		} else {
-			if (deleteAccount) briarController.deleteAccount();
-			exit(removeFromRecentApps);
-		}
+		// Hold a wake lock to ensure we exit before the device goes to sleep
+		wakeLockManager.runWakefully(() -> {
+			if (briarController.accountSignedIn()) {
+				// Don't use UiResultHandler because we want the result even if
+				// this activity has been destroyed
+				briarController.signOut(result -> {
+					Runnable exit = () -> exit(removeFromRecentApps);
+					wakeLockManager.executeWakefully(exit,
+							this::runOnUiThread, "SignOut");
+				}, deleteAccount);
+			} else {
+				if (deleteAccount) briarController.deleteAccount();
+				exit(removeFromRecentApps);
+			}
+		}, "SignOut");
 	}
 
+	@Wakeful
 	private void exit(boolean removeFromRecentApps) {
 		if (removeFromRecentApps) startExitActivity();
 		else finishAndExit();
 	}
 
+	@Wakeful
 	private void startExitActivity() {
 		Intent i = new Intent(this, ExitActivity.class);
 		i.addFlags(FLAG_ACTIVITY_NEW_TASK
@@ -222,6 +236,7 @@ public abstract class BriarActivity extends BaseActivity {
 		startActivity(i);
 	}
 
+	@Wakeful
 	private void finishAndExit() {
 		if (SDK_INT >= 21) finishAndRemoveTask();
 		else supportFinishAfterTransition();

briar-android/src/main/java/org/briarproject/briar/android/controller/BriarController.java

@@ -1,7 +1,10 @@
 package org.briarproject.briar.android.controller;
 
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.system.Wakeful;
 import org.briarproject.briar.android.controller.handler.ResultHandler;
 
+@NotNullByDefault
 public interface BriarController extends ActivityLifecycleController {
 
 	void startAndBindService();
@@ -16,7 +19,8 @@ public interface BriarController extends ActivityLifecycleController {
 
 	void doNotAskAgainForDozeWhiteListing();
 
-	void signOut(ResultHandler<Void> eventHandler, boolean deleteAccount);
+	@Wakeful
+	void signOut(ResultHandler<Void> handler, boolean deleteAccount);
 
 	void deleteAccount();
 

briar-android/src/main/java/org/briarproject/briar/android/controller/BriarControllerImpl.java

@@ -8,8 +8,10 @@ import org.briarproject.bramble.api.account.AccountManager;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.settings.Settings;
 import org.briarproject.bramble.api.settings.SettingsManager;
+import org.briarproject.bramble.api.system.AndroidWakeLockManager;
 import org.briarproject.briar.android.BriarService;
 import org.briarproject.briar.android.BriarService.BriarServiceConnection;
 import org.briarproject.briar.android.controller.handler.ResultHandler;
@@ -23,15 +25,17 @@ import javax.inject.Inject;
 import androidx.annotation.CallSuper;
 
 import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.STARTING_SERVICES;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.briar.android.settings.SettingsFragment.SETTINGS_NAMESPACE;
 import static org.briarproject.briar.android.util.UiUtils.needsDozeWhitelisting;
 
+@NotNullByDefault
 public class BriarControllerImpl implements BriarController {
 
 	private static final Logger LOG =
-			Logger.getLogger(BriarControllerImpl.class.getName());
+			getLogger(BriarControllerImpl.class.getName());
 
 	public static final String DOZE_ASK_AGAIN = "dozeAskAgain";
 
@@ -41,6 +45,7 @@ public class BriarControllerImpl implements BriarController {
 	private final Executor databaseExecutor;
 	private final SettingsManager settingsManager;
 	private final DozeWatchdog dozeWatchdog;
+	private final AndroidWakeLockManager wakeLockManager;
 	private final Activity activity;
 
 	private boolean bound = false;
@@ -50,7 +55,9 @@ public class BriarControllerImpl implements BriarController {
 			AccountManager accountManager,
 			LifecycleManager lifecycleManager,
 			@DatabaseExecutor Executor databaseExecutor,
-			SettingsManager settingsManager, DozeWatchdog dozeWatchdog,
+			SettingsManager settingsManager,
+			DozeWatchdog dozeWatchdog,
+			AndroidWakeLockManager wakeLockManager,
 			Activity activity) {
 		this.serviceConnection = serviceConnection;
 		this.accountManager = accountManager;
@@ -58,6 +65,7 @@ public class BriarControllerImpl implements BriarController {
 		this.databaseExecutor = databaseExecutor;
 		this.settingsManager = settingsManager;
 		this.dozeWatchdog = dozeWatchdog;
+		this.wakeLockManager = wakeLockManager;
 		this.activity = activity;
 	}
 
@@ -127,9 +135,8 @@ public class BriarControllerImpl implements BriarController {
 	}
 
 	@Override
-	public void signOut(ResultHandler<Void> eventHandler,
-			boolean deleteAccount) {
-		new Thread(() -> {
+	public void signOut(ResultHandler<Void> handler, boolean deleteAccount) {
+		wakeLockManager.executeWakefully(() -> {
 			try {
 				// Wait for the service to finish starting up
 				IBinder binder = serviceConnection.waitForBinder();
@@ -145,8 +152,8 @@ public class BriarControllerImpl implements BriarController {
 			} finally {
 				if (deleteAccount) accountManager.deleteAccount();
 			}
-			eventHandler.onResult(null);
-		}).start();
+			handler.onResult(null);
+		}, "SignOut");
 	}
 
 	@Override

briar-android/src/main/java/org/briarproject/briar/android/panic/PanicResponderActivity.java

@@ -4,17 +4,14 @@ import android.content.Intent;
 import android.content.SharedPreferences;
 import android.os.Bundle;
 
-import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
-import org.briarproject.bramble.api.system.AndroidExecutor;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BriarActivity;
 
 import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
-import javax.inject.Inject;
 
 import androidx.preference.PreferenceManager;
 import info.guardianproject.GuardianProjectRSA4096;
@@ -23,6 +20,7 @@ import info.guardianproject.panic.PanicResponder;
 import info.guardianproject.trustedintents.TrustedIntents;
 
 import static android.os.Build.VERSION.SDK_INT;
+import static java.util.logging.Logger.getLogger;
 import static org.briarproject.briar.android.panic.PanicPreferencesFragment.KEY_LOCK;
 import static org.briarproject.briar.android.panic.PanicPreferencesFragment.KEY_PURGE;
 
@@ -31,12 +29,7 @@ import static org.briarproject.briar.android.panic.PanicPreferencesFragment.KEY_
 public class PanicResponderActivity extends BriarActivity {
 
 	private static final Logger LOG =
-			Logger.getLogger(PanicResponderActivity.class.getName());
-
-	@Inject
-	protected LifecycleManager lifecycleManager;
-	@Inject
-	protected AndroidExecutor androidExecutor;
+			getLogger(PanicResponderActivity.class.getName());
 
 	@Override
 	public void onCreate(@Nullable Bundle savedInstanceState) {
@@ -63,13 +56,20 @@ public class PanicResponderActivity extends BriarActivity {
 					// Performing panic responses
 					if (sharedPref.getBoolean(KEY_PURGE, false)) {
 						LOG.info("Purging all data...");
-						deleteAllData();
+						signOut(true, true);
+					} else if (sharedPref.getBoolean(KEY_LOCK, true)) {
+						LOG.info("Signing out...");
+						signOut(true, false);
+					} else {
+						LOG.info("Configured not to purge or lock");
 					}
-				}
-				// non-destructive actions are allowed by non-connected trusted apps
-				if (sharedPref.getBoolean(KEY_LOCK, true)) {
+				} else if (sharedPref.getBoolean(KEY_LOCK, true)) {
+					// non-destructive actions are allowed by non-connected
+					// trusted apps
 					LOG.info("Signing out...");
 					signOut(true, false);
+				} else {
+					LOG.info("Configured not to lock");
 				}
 			}
 		}
@@ -85,11 +85,4 @@ public class PanicResponderActivity extends BriarActivity {
 	public void injectActivity(ActivityComponent component) {
 		component.inject(this);
 	}
-
-	private void deleteAllData() {
-		androidExecutor.runOnBackgroundThread(() -> {
-			LOG.info("Signing out...");
-			signOut(true, true);
-		});
-	}
 }

briar-core/src/main/java/org/briarproject/briar/feed/FeedManagerImpl.java

@@ -30,6 +30,7 @@ import org.briarproject.bramble.api.sync.Group;
 import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.TaskScheduler;
+import org.briarproject.bramble.api.system.Wakeful;
 import org.briarproject.bramble.util.StringUtils;
 import org.briarproject.briar.api.blog.Blog;
 import org.briarproject.briar.api.blog.BlogManager;
@@ -284,7 +285,7 @@ class FeedManagerImpl implements FeedManager, EventListener, OpenDatabaseHook,
 	}
 
 	/**
-	 * This method is called periodically from a background service.
+	 * This method is called periodically by the task scheduler.
 	 * It fetches all available feeds and posts new entries to the respective
 	 * blog.
 	 * <p>
@@ -292,6 +293,7 @@ class FeedManagerImpl implements FeedManager, EventListener, OpenDatabaseHook,
 	 * because fetching can take a long time
 	 * and we can not block the database that long.
 	 */
+	@Wakeful
 	void fetchFeeds() {
 		if (!torActive) return;
 		LOG.info("Updating RSS feeds...");