Add a simple Tor relay probe.

.idea/runConfigurations/All_in_briar_headless.xml

@@ -3,7 +3,7 @@
     <module name="briar-headless" />
     <option name="ALTERNATIVE_JRE_PATH_ENABLED" value="false" />
     <option name="ALTERNATIVE_JRE_PATH" />
-    <option name="PACKAGE_NAME" value="org.briarproject.briar.headless" />
+    <option name="PACKAGE_NAME" value="" />
     <option name="MAIN_CLASS_NAME" value="" />
     <option name="METHOD_NAME" value="" />
     <option name="TEST_OBJECT" value="package" />

bramble-android/build.gradle

@@ -1,5 +1,3 @@
-import com.android.build.gradle.tasks.MergeResources
-
 apply plugin: 'com.android.library'
 apply plugin: 'witness'
 apply from: 'witness.gradle'
@@ -11,8 +9,8 @@ android {
 	defaultConfig {
 		minSdkVersion 14
 		targetSdkVersion 26
-		versionCode 10105
+		versionCode 10103
-		versionName "1.1.5"
+		versionName "1.1.3"
 		consumerProguardFiles 'proguard-rules.txt'
 
 		testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
@@ -31,9 +29,8 @@ configurations {
 dependencies {
 	implementation project(path: ':bramble-core', configuration: 'default')
 	tor 'org.briarproject:tor-android:0.3.4.8@zip'
-	tor 'org.briarproject:obfs4proxy-android:0.0.7@zip'
 
-	annotationProcessor 'com.google.dagger:dagger-compiler:2.19'
+	annotationProcessor 'com.google.dagger:dagger-compiler:2.0.2'
 
 	compileOnly 'javax.annotation:jsr250-api:1.0'
 
@@ -42,29 +39,13 @@ dependencies {
 	testImplementation "org.jmock:jmock:2.8.2"
 	testImplementation "org.jmock:jmock-junit4:2.8.2"
 	testImplementation "org.jmock:jmock-legacy:2.8.2"
+	testImplementation "org.hamcrest:hamcrest-library:1.3"
+	testImplementation "org.hamcrest:hamcrest-core:1.3"
 }
 
-def torBinariesDir = 'src/main/res/raw'
+project.afterEvaluate {
-
+	copy {
-task cleanTorBinaries {
+		from configurations.tor.collect { zipTree(it) }
-	doLast {
+		into 'src/main/res/raw'
-		delete fileTree(torBinariesDir) { include '*.zip' }
 	}
 }
-
-clean.dependsOn cleanTorBinaries
-
-task unpackTorBinaries {
-	doLast {
-		copy {
-			from configurations.tor.collect { zipTree(it) }
-			into torBinariesDir
-		}
-	}
-	dependsOn cleanTorBinaries
-}
-
-tasks.withType(MergeResources) {
-	inputs.dir torBinariesDir
-	dependsOn unpackTorBinaries
-}

bramble-android/src/main/java/org/briarproject/bramble/BrambleAndroidEagerSingletons.java

@@ -1,11 +0,0 @@
-package org.briarproject.bramble;
-
-import org.briarproject.bramble.battery.AndroidBatteryModule;
-import org.briarproject.bramble.network.AndroidNetworkModule;
-
-public interface BrambleAndroidEagerSingletons {
-
-	void inject(AndroidBatteryModule.EagerSingletons init);
-
-	void inject(AndroidNetworkModule.EagerSingletons init);
-}

bramble-android/src/main/java/org/briarproject/bramble/BrambleAndroidModule.java

@@ -1,6 +1,5 @@
 package org.briarproject.bramble;
 
-import org.briarproject.bramble.battery.AndroidBatteryModule;
 import org.briarproject.bramble.network.AndroidNetworkModule;
 import org.briarproject.bramble.plugin.tor.CircumventionModule;
 import org.briarproject.bramble.system.AndroidSystemModule;
@@ -8,15 +7,10 @@ import org.briarproject.bramble.system.AndroidSystemModule;
 import dagger.Module;
 
 @Module(includes = {
-		AndroidBatteryModule.class,
 		AndroidNetworkModule.class,
 		AndroidSystemModule.class,
 		CircumventionModule.class
 })
 public class BrambleAndroidModule {
 
-	public static void initEagerSingletons(BrambleAndroidEagerSingletons c) {
-		c.inject(new AndroidBatteryModule.EagerSingletons());
-		c.inject(new AndroidNetworkModule.EagerSingletons());
-	}
 }

bramble-android/src/main/java/org/briarproject/bramble/battery/AndroidBatteryManager.java

@@ -1,84 +0,0 @@
-package org.briarproject.bramble.battery;
-
-import android.app.Application;
-import android.content.BroadcastReceiver;
-import android.content.Context;
-import android.content.Intent;
-import android.content.IntentFilter;
-
-import org.briarproject.bramble.api.battery.BatteryManager;
-import org.briarproject.bramble.api.battery.event.BatteryEvent;
-import org.briarproject.bramble.api.event.EventBus;
-import org.briarproject.bramble.api.lifecycle.Service;
-
-import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.logging.Logger;
-
-import javax.inject.Inject;
-
-import static android.content.Intent.ACTION_BATTERY_CHANGED;
-import static android.content.Intent.ACTION_POWER_CONNECTED;
-import static android.content.Intent.ACTION_POWER_DISCONNECTED;
-import static android.os.BatteryManager.BATTERY_STATUS_CHARGING;
-import static android.os.BatteryManager.BATTERY_STATUS_FULL;
-import static android.os.BatteryManager.EXTRA_STATUS;
-import static java.util.logging.Level.INFO;
-import static java.util.logging.Logger.getLogger;
-
-class AndroidBatteryManager implements BatteryManager, Service {
-
-	private static final Logger LOG =
-			getLogger(AndroidBatteryManager.class.getName());
-
-	private final Context appContext;
-	private final EventBus eventBus;
-	private final AtomicBoolean used = new AtomicBoolean(false);
-
-	private volatile BroadcastReceiver batteryReceiver = null;
-
-	@Inject
-	AndroidBatteryManager(Application app, EventBus eventBus) {
-		this.appContext = app.getApplicationContext();
-		this.eventBus = eventBus;
-	}
-
-	@Override
-	public boolean isCharging() {
-		// Get the sticky intent for ACTION_BATTERY_CHANGED
-		IntentFilter filter = new IntentFilter(ACTION_BATTERY_CHANGED);
-		Intent i = appContext.registerReceiver(null, filter);
-		if (i == null) return false;
-		int status = i.getIntExtra(EXTRA_STATUS, -1);
-		return status == BATTERY_STATUS_CHARGING ||
-				status == BATTERY_STATUS_FULL;
-	}
-
-	@Override
-	public void startService() {
-		if (used.getAndSet(true)) throw new IllegalStateException();
-		batteryReceiver = new BatteryReceiver();
-		IntentFilter filter = new IntentFilter();
-		filter.addAction(ACTION_POWER_CONNECTED);
-		filter.addAction(ACTION_POWER_DISCONNECTED);
-		appContext.registerReceiver(batteryReceiver, filter);
-	}
-
-	@Override
-	public void stopService() {
-		if (batteryReceiver != null)
-			appContext.unregisterReceiver(batteryReceiver);
-	}
-
-	private class BatteryReceiver extends BroadcastReceiver {
-
-		@Override
-		public void onReceive(Context ctx, Intent i) {
-			String action = i.getAction();
-			if (LOG.isLoggable(INFO)) LOG.info("Received broadcast " + action);
-			if (ACTION_POWER_CONNECTED.equals(action))
-				eventBus.broadcast(new BatteryEvent(true));
-			else if (ACTION_POWER_DISCONNECTED.equals(action))
-				eventBus.broadcast(new BatteryEvent(false));
-		}
-	}
-}

bramble-android/src/main/java/org/briarproject/bramble/battery/AndroidBatteryModule.java

@@ -1,27 +0,0 @@
-package org.briarproject.bramble.battery;
-
-import org.briarproject.bramble.api.battery.BatteryManager;
-import org.briarproject.bramble.api.lifecycle.LifecycleManager;
-
-import javax.inject.Inject;
-import javax.inject.Singleton;
-
-import dagger.Module;
-import dagger.Provides;
-
-@Module
-public class AndroidBatteryModule {
-
-	public static class EagerSingletons {
-		@Inject
-		BatteryManager batteryManager;
-	}
-
-	@Provides
-	@Singleton
-	BatteryManager provideBatteryManager(LifecycleManager lifecycleManager,
-			AndroidBatteryManager batteryManager) {
-		lifecycleManager.registerService(batteryManager);
-		return batteryManager;
-	}
-}

bramble-android/src/main/java/org/briarproject/bramble/network/AndroidNetworkModule.java

@@ -3,7 +3,6 @@ package org.briarproject.bramble.network;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.network.NetworkManager;
 
-import javax.inject.Inject;
 import javax.inject.Singleton;
 
 import dagger.Module;
@@ -12,11 +11,6 @@ import dagger.Provides;
 @Module
 public class AndroidNetworkModule {
 
-	public static class EagerSingletons {
-		@Inject
-		NetworkManager networkManager;
-	}
-
 	@Provides
 	@Singleton
 	NetworkManager provideNetworkManager(LifecycleManager lifecycleManager,

bramble-android/src/main/java/org/briarproject/bramble/plugin/bluetooth/AndroidBluetoothPlugin.java

@@ -16,27 +16,18 @@ import org.briarproject.bramble.api.plugin.PluginException;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.system.AndroidExecutor;
-import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.util.AndroidUtils;
-import org.briarproject.bramble.util.IoUtils;
 
+import java.io.Closeable;
 import java.io.IOException;
 import java.security.SecureRandom;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.List;
 import java.util.UUID;
-import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Executor;
-import java.util.concurrent.LinkedBlockingQueue;
 import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
 
-import static android.bluetooth.BluetoothAdapter.ACTION_DISCOVERY_FINISHED;
-import static android.bluetooth.BluetoothAdapter.ACTION_DISCOVERY_STARTED;
 import static android.bluetooth.BluetoothAdapter.ACTION_SCAN_MODE_CHANGED;
 import static android.bluetooth.BluetoothAdapter.ACTION_STATE_CHANGED;
 import static android.bluetooth.BluetoothAdapter.EXTRA_SCAN_MODE;
@@ -46,12 +37,8 @@ import static android.bluetooth.BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERA
 import static android.bluetooth.BluetoothAdapter.SCAN_MODE_NONE;
 import static android.bluetooth.BluetoothAdapter.STATE_OFF;
 import static android.bluetooth.BluetoothAdapter.STATE_ON;
-import static android.bluetooth.BluetoothDevice.ACTION_FOUND;
-import static android.bluetooth.BluetoothDevice.EXTRA_DEVICE;
-import static java.util.concurrent.TimeUnit.MILLISECONDS;
-import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.util.PrivacyUtils.scrubMacAddress;
+import static org.briarproject.bramble.util.LogUtils.logException;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
@@ -60,11 +47,8 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 	private static final Logger LOG =
 			Logger.getLogger(AndroidBluetoothPlugin.class.getName());
 
-	private static final int MAX_DISCOVERY_MS = 10_000;
-
 	private final AndroidExecutor androidExecutor;
 	private final Context appContext;
-	private final Clock clock;
 
 	private volatile boolean wasEnabledByUs = false;
 	private volatile BluetoothStateReceiver receiver = null;
@@ -74,13 +58,12 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 
 	AndroidBluetoothPlugin(BluetoothConnectionLimiter connectionLimiter,
 			Executor ioExecutor, AndroidExecutor androidExecutor,
-			Context appContext, SecureRandom secureRandom, Clock clock,
+			Context appContext, SecureRandom secureRandom, Backoff backoff,
-			Backoff backoff, DuplexPluginCallback callback, int maxLatency) {
+			DuplexPluginCallback callback, int maxLatency) {
 		super(connectionLimiter, ioExecutor, secureRandom, backoff, callback,
 				maxLatency);
 		this.androidExecutor = androidExecutor;
 		this.appContext = appContext;
-		this.clock = clock;
 	}
 
 	@Override
@@ -160,7 +143,11 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 
 	@Override
 	void tryToClose(@Nullable BluetoothServerSocket ss) {
-		IoUtils.tryToClose(ss, LOG, WARNING);
+		try {
+			if (ss != null) ss.close();
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+		}
 	}
 
 	@Override
@@ -190,77 +177,17 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 			s.connect();
 			return wrapSocket(s);
 		} catch (IOException e) {
-			IoUtils.tryToClose(s, LOG, WARNING);
+			tryToClose(s);
 			throw e;
 		}
 	}
 
-	@Override
+	private void tryToClose(@Nullable Closeable c) {
-	@Nullable
-	DuplexTransportConnection discoverAndConnect(String uuid) {
-		if (adapter == null) return null;
-		for (String address : discoverDevices()) {
-			try {
-				if (LOG.isLoggable(INFO))
-					LOG.info("Connecting to " + scrubMacAddress(address));
-				return connectTo(address, uuid);
-			} catch (IOException e) {
-				if (LOG.isLoggable(INFO)) {
-					LOG.info("Could not connect to "
-							+ scrubMacAddress(address));
-				}
-			}
-		}
-		LOG.info("Could not connect to any devices");
-		return null;
-	}
-
-	private Collection<String> discoverDevices() {
-		List<String> addresses = new ArrayList<>();
-		BlockingQueue<Intent> intents = new LinkedBlockingQueue<>();
-		DiscoveryReceiver receiver = new DiscoveryReceiver(intents);
-		IntentFilter filter = new IntentFilter();
-		filter.addAction(ACTION_DISCOVERY_STARTED);
-		filter.addAction(ACTION_DISCOVERY_FINISHED);
-		filter.addAction(ACTION_FOUND);
-		appContext.registerReceiver(receiver, filter);
 		try {
-			if (adapter.startDiscovery()) {
+			if (c != null) c.close();
-				long now = clock.currentTimeMillis();
+		} catch (IOException e) {
-				long end = now + MAX_DISCOVERY_MS;
+			logException(LOG, WARNING, e);
-				while (now < end) {
-					Intent i = intents.poll(end - now, MILLISECONDS);
-					if (i == null) break;
-					String action = i.getAction();
-					if (ACTION_DISCOVERY_STARTED.equals(action)) {
-						LOG.info("Discovery started");
-					} else if (ACTION_DISCOVERY_FINISHED.equals(action)) {
-						LOG.info("Discovery finished");
-						break;
-					} else if (ACTION_FOUND.equals(action)) {
-						BluetoothDevice d = i.getParcelableExtra(EXTRA_DEVICE);
-						String address = d.getAddress();
-						if (LOG.isLoggable(INFO))
-							LOG.info("Discovered " + scrubMacAddress(address));
-						if (!addresses.contains(address))
-							addresses.add(address);
-					}
-					now = clock.currentTimeMillis();
-				}
-			} else {
-				LOG.info("Could not start discovery");
-			}
-		} catch (InterruptedException e) {
-			LOG.info("Interrupted while discovering devices");
-			Thread.currentThread().interrupt();
-		} finally {
-			LOG.info("Cancelling discovery");
-			adapter.cancelDiscovery();
-			appContext.unregisterReceiver(receiver);
 		}
-		// Shuffle the addresses so we don't always try the same one first
-		Collections.shuffle(addresses);
-		return addresses;
 	}
 
 	private class BluetoothStateReceiver extends BroadcastReceiver {
@@ -280,18 +207,4 @@ class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
 			}
 		}
 	}
-
-	private static class DiscoveryReceiver extends BroadcastReceiver {
-
-		private final BlockingQueue<Intent> intents;
-
-		private DiscoveryReceiver(BlockingQueue<Intent> intents) {
-			this.intents = intents;
-		}
-
-		@Override
-		public void onReceive(Context ctx, Intent intent) {
-			intents.add(intent);
-		}
-	}
 }

bramble-android/src/main/java/org/briarproject/bramble/plugin/bluetooth/AndroidBluetoothPluginFactory.java

@@ -11,7 +11,6 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginFactory;
 import org.briarproject.bramble.api.system.AndroidExecutor;
-import org.briarproject.bramble.api.system.Clock;
 
 import java.security.SecureRandom;
 import java.util.concurrent.Executor;
@@ -34,19 +33,17 @@ public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 	private final Context appContext;
 	private final SecureRandom secureRandom;
 	private final EventBus eventBus;
-	private final Clock clock;
 	private final BackoffFactory backoffFactory;
 
 	public AndroidBluetoothPluginFactory(Executor ioExecutor,
 			AndroidExecutor androidExecutor, Context appContext,
-			SecureRandom secureRandom, EventBus eventBus, Clock clock,
+			SecureRandom secureRandom, EventBus eventBus,
 			BackoffFactory backoffFactory) {
 		this.ioExecutor = ioExecutor;
 		this.androidExecutor = androidExecutor;
 		this.appContext = appContext;
 		this.secureRandom = secureRandom;
 		this.eventBus = eventBus;
-		this.clock = clock;
 		this.backoffFactory = backoffFactory;
 	}
 
@@ -68,7 +65,7 @@ public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
 		AndroidBluetoothPlugin plugin = new AndroidBluetoothPlugin(
 				connectionLimiter, ioExecutor, androidExecutor, appContext,
-				secureRandom, clock, backoff, callback, MAX_LATENCY);
+				secureRandom, backoff, callback, MAX_LATENCY);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

bramble-android/src/main/java/org/briarproject/bramble/plugin/tor/AndroidTorPlugin.java

@@ -6,7 +6,6 @@ import android.content.pm.PackageManager;
 import android.content.pm.PackageManager.NameNotFoundException;
 import android.os.PowerManager;
 
-import org.briarproject.bramble.api.battery.BatteryManager;
 import org.briarproject.bramble.api.network.NetworkManager;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
@@ -42,18 +41,17 @@ class AndroidTorPlugin extends TorPlugin {
 			Context appContext, NetworkManager networkManager,
 			LocationUtils locationUtils, SocketFactory torSocketFactory,
 			Clock clock, ResourceProvider resourceProvider,
-			CircumventionProvider circumventionProvider,
+			CircumventionProvider circumventionProvider, Backoff backoff,
-			BatteryManager batteryManager, Backoff backoff,
 			DuplexPluginCallback callback, String architecture, int maxLatency,
 			int maxIdleTime) {
 		super(ioExecutor, networkManager, locationUtils, torSocketFactory,
-				clock, resourceProvider, circumventionProvider, batteryManager,
+				clock, resourceProvider, circumventionProvider, backoff,
-				backoff, callback, architecture, maxLatency, maxIdleTime,
+				callback, architecture, maxLatency, maxIdleTime,
 				appContext.getDir("tor", MODE_PRIVATE));
 		this.appContext = appContext;
 		PowerManager pm = (PowerManager)
 				appContext.getSystemService(POWER_SERVICE);
-		if (pm == null) throw new AssertionError();
+		assert pm != null;
 		wakeLock = new RenewableWakeLock(pm, scheduler, PARTIAL_WAKE_LOCK,
 				WAKE_LOCK_TAG, 1, MINUTES);
 	}

bramble-android/src/main/java/org/briarproject/bramble/plugin/tor/AndroidTorPluginFactory.java

@@ -3,7 +3,6 @@ package org.briarproject.bramble.plugin.tor;
 import android.content.Context;
 import android.os.Build;
 
-import org.briarproject.bramble.api.battery.BatteryManager;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.network.NetworkManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
@@ -49,7 +48,6 @@ public class AndroidTorPluginFactory implements DuplexPluginFactory {
 	private final BackoffFactory backoffFactory;
 	private final ResourceProvider resourceProvider;
 	private final CircumventionProvider circumventionProvider;
-	private final BatteryManager batteryManager;
 	private final Clock clock;
 
 	public AndroidTorPluginFactory(Executor ioExecutor,
@@ -57,8 +55,7 @@ public class AndroidTorPluginFactory implements DuplexPluginFactory {
 			NetworkManager networkManager, LocationUtils locationUtils,
 			EventBus eventBus, SocketFactory torSocketFactory,
 			BackoffFactory backoffFactory, ResourceProvider resourceProvider,
-			CircumventionProvider circumventionProvider,
+			CircumventionProvider circumventionProvider, Clock clock) {
-			BatteryManager batteryManager, Clock clock) {
 		this.ioExecutor = ioExecutor;
 		this.scheduler = scheduler;
 		this.appContext = appContext;
@@ -69,7 +66,6 @@ public class AndroidTorPluginFactory implements DuplexPluginFactory {
 		this.backoffFactory = backoffFactory;
 		this.resourceProvider = resourceProvider;
 		this.circumventionProvider = circumventionProvider;
-		this.batteryManager = batteryManager;
 		this.clock = clock;
 	}
 
@@ -108,8 +104,8 @@ public class AndroidTorPluginFactory implements DuplexPluginFactory {
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
 		AndroidTorPlugin plugin = new AndroidTorPlugin(ioExecutor, scheduler,
 				appContext, networkManager, locationUtils, torSocketFactory,
-				clock, resourceProvider, circumventionProvider, batteryManager,
+				clock, resourceProvider, circumventionProvider, backoff,
-				backoff, callback, architecture, MAX_LATENCY, MAX_IDLE_TIME);
+				callback, architecture, MAX_LATENCY, MAX_IDLE_TIME);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

bramble-android/src/main/java/org/briarproject/bramble/plugin/tor/TorProbe.java

@@ -0,0 +1,153 @@
+package org.briarproject.bramble.plugin.tor;
+
+import org.spongycastle.crypto.tls.Certificate;
+import org.spongycastle.crypto.tls.CipherSuite;
+import org.spongycastle.crypto.tls.DefaultTlsClient;
+import org.spongycastle.crypto.tls.ServerOnlyTlsAuthentication;
+import org.spongycastle.crypto.tls.TlsAuthentication;
+import org.spongycastle.crypto.tls.TlsClientProtocol;
+
+import java.io.DataInputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.net.Socket;
+import java.security.SecureRandom;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.logging.Logger;
+
+import static java.util.logging.Level.INFO;
+
+public class TorProbe {
+
+	private static final Logger LOG =
+			Logger.getLogger(TorProbe.class.getName());
+
+	private static final int READ_TIMEOUT = 10 * 1000;
+
+	// https://trac.torproject.org/projects/tor/wiki/org/projects/Tor/TLSHistory
+	private static final int SSL3_RSA_FIPS_WITH_3DES_EDE_CBC_SHA = 0xfeff;
+
+	// https://gitweb.torproject.org/torspec.git/tree/tor-spec.txt#n347
+	private static final int[] TOR_CIPHER_SUITES = new int[] {
+			CipherSuite.TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
+			CipherSuite.TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA,
+			CipherSuite.TLS_DHE_RSA_WITH_AES_256_CBC_SHA,
+			CipherSuite.TLS_DHE_DSS_WITH_AES_256_CBC_SHA,
+			CipherSuite.TLS_ECDH_RSA_WITH_AES_256_CBC_SHA,
+			CipherSuite.TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA,
+			CipherSuite.TLS_RSA_WITH_AES_256_CBC_SHA,
+			CipherSuite.TLS_ECDHE_ECDSA_WITH_RC4_128_SHA,
+			CipherSuite.TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
+			CipherSuite.TLS_ECDHE_RSA_WITH_RC4_128_SHA,
+			CipherSuite.TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA,
+			CipherSuite.TLS_DHE_RSA_WITH_AES_128_CBC_SHA,
+			CipherSuite.TLS_DHE_DSS_WITH_AES_128_CBC_SHA,
+			CipherSuite.TLS_ECDH_RSA_WITH_RC4_128_SHA,
+			CipherSuite.TLS_ECDH_RSA_WITH_AES_128_CBC_SHA,
+			CipherSuite.TLS_ECDH_ECDSA_WITH_RC4_128_SHA,
+			CipherSuite.TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA,
+			CipherSuite.TLS_RSA_WITH_RC4_128_MD5,
+			CipherSuite.TLS_RSA_WITH_RC4_128_SHA,
+			CipherSuite.TLS_RSA_WITH_AES_128_CBC_SHA,
+			CipherSuite.TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA,
+			CipherSuite.TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA,
+			CipherSuite.TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA,
+			CipherSuite.TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA,
+			CipherSuite.TLS_ECDH_RSA_WITH_3DES_EDE_CBC_SHA,
+			CipherSuite.TLS_ECDH_ECDSA_WITH_3DES_EDE_CBC_SHA,
+			SSL3_RSA_FIPS_WITH_3DES_EDE_CBC_SHA,
+			CipherSuite.TLS_RSA_WITH_3DES_EDE_CBC_SHA
+	};
+
+	// https://gitweb.torproject.org/torspec.git/tree/tor-spec.txt#n412
+	private static final byte[] VERSIONS_CELL = new byte[] {
+			0x00, 0x00, // Circuit ID: 0
+			0x07, // Command: Versions
+			0x00, 0x06, // Payload length: 6 bytes
+			0x00, 0x03, 0x00, 0x04, 0x00, 0x05 // Supported versions: 3, 4, 5
+	};
+
+	public List<Integer> probe(String address, int port) throws IOException {
+		if (LOG.isLoggable(INFO))
+			LOG.info("Connecting to " + address + ":" + port);
+		Socket socket = new Socket(address, port);
+		LOG.info("Connected");
+		TlsClientProtocol client = new TlsClientProtocol(
+				socket.getInputStream(), socket.getOutputStream(),
+				new SecureRandom());
+		client.connect(new TorTlsClient());
+		LOG.info("TLS handshake succeeded");
+		socket.setSoTimeout(READ_TIMEOUT);
+		try {
+			// Send a versions cell
+			OutputStream out = client.getOutputStream();
+			out.write(VERSIONS_CELL);
+			out.flush();
+			LOG.info("Sent versions cell");
+
+			// Expect a versions cell in response
+			List<Integer> versions = new ArrayList<>();
+			DataInputStream in = new DataInputStream(client.getInputStream());
+			int circuitId = in.readUnsignedShort();
+			if (circuitId != 0)
+				throw new IOException("Unexpected circuit ID: " + circuitId);
+			int command = in.readUnsignedByte();
+			if (command != 7)
+				throw new IOException("Unexpected command: " + command);
+			int payloadLength = in.readUnsignedShort();
+			if (payloadLength == 0 || payloadLength % 2 != 0) {
+				throw new IOException("Invalid payload length: "
+						+ payloadLength);
+			}
+			for (int i = 0; i < payloadLength / 2; i++) {
+				int version = in.readUnsignedShort();
+				versions.add(version);
+			}
+			if (LOG.isLoggable(INFO))
+				LOG.info("Supported versions: " + versions);
+			return versions;
+		} finally {
+			client.close();
+		}
+	}
+
+	public static void main(String[] args) throws IOException {
+		if (args.length != 2) {
+			System.err.println("Usage: TorProbe <address> <port>");
+			System.exit(1);
+		}
+		String address = args[0];
+		int port = Integer.parseInt(args[1]);
+		new TorProbe().probe(address, port);
+	}
+
+	private static class TorTlsClient extends DefaultTlsClient {
+
+		@Override
+		public TlsAuthentication getAuthentication() {
+			return new ServerOnlyTlsAuthentication() {
+				@Override
+				public void notifyServerCertificate(Certificate cert)
+						throws IOException {
+					LOG.info("Received server certificate");
+					org.spongycastle.asn1.x509.Certificate[] chain =
+							cert.getCertificateList();
+					if (chain.length != 1)
+						throw new IOException("Certificate is not self-signed");
+					for (org.spongycastle.asn1.x509.Certificate c : chain) {
+						if (LOG.isLoggable(INFO)) {
+							LOG.info("Subject: " + c.getSubject());
+							LOG.info("Issuer: " + c.getIssuer());
+						}
+					}
+				}
+			};
+		}
+
+		@Override
+		public int[] getCipherSuites() {
+			return TOR_CIPHER_SUITES;
+		}
+	}
+}

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

@@ -1,6 +1,5 @@
 package org.briarproject.bramble.system;
 
-import android.annotation.SuppressLint;
 import android.app.Application;
 import android.bluetooth.BluetoothAdapter;
 import android.bluetooth.BluetoothDevice;
@@ -27,7 +26,7 @@ import static android.provider.Settings.Secure.ANDROID_ID;
 
 @Immutable
 @NotNullByDefault
-class AndroidSecureRandomProvider extends UnixSecureRandomProvider {
+class AndroidSecureRandomProvider extends LinuxSecureRandomProvider {
 
 	private static final int SEED_LENGTH = 32;
 
@@ -38,7 +37,6 @@ class AndroidSecureRandomProvider extends UnixSecureRandomProvider {
 		appContext = app.getApplicationContext();
 	}
 
-	@SuppressLint("HardwareIds")
 	@Override
 	protected void writeToEntropyPool(DataOutputStream out) throws IOException {
 		super.writeToEntropyPool(out);
@@ -51,14 +49,12 @@ class AndroidSecureRandomProvider extends UnixSecureRandomProvider {
 		String id = Settings.Secure.getString(contentResolver, ANDROID_ID);
 		if (id != null) out.writeUTF(id);
 		Parcel parcel = Parcel.obtain();
-		WifiManager wm = (WifiManager) appContext.getApplicationContext()
+		WifiManager wm =
-				.getSystemService(WIFI_SERVICE);
+				(WifiManager) appContext.getSystemService(WIFI_SERVICE);
-		if (wm != null) {
+		List<WifiConfiguration> configs = wm.getConfiguredNetworks();
-			List<WifiConfiguration> configs = wm.getConfiguredNetworks();
+		if (configs != null) {
-			if (configs != null) {
+			for (WifiConfiguration config : configs)
-				for (WifiConfiguration config : configs)
+				parcel.writeParcelable(config, 0);
-					parcel.writeParcelable(config, 0);
-			}
 		}
 		BluetoothAdapter bt = BluetoothAdapter.getDefaultAdapter();
 		if (bt != null) {
@@ -81,13 +77,13 @@ class AndroidSecureRandomProvider extends UnixSecureRandomProvider {
 
 	// Based on https://android-developers.googleblog.com/2013/08/some-securerandom-thoughts.html
 	private void applyOpenSslFix() {
-		byte[] seed = new UnixSecureRandomSpi().engineGenerateSeed(
+		byte[] seed = new LinuxSecureRandomSpi().engineGenerateSeed(
 				SEED_LENGTH);
 		try {
 			// Seed the OpenSSL PRNG
 			Class.forName("org.apache.harmony.xnet.provider.jsse.NativeCrypto")
 					.getMethod("RAND_seed", byte[].class)
-					.invoke(null, (Object) seed);
+					.invoke(null, seed);
 			// Mix the output of the Linux PRNG into the OpenSSL PRNG
 			int bytesRead = (Integer) Class.forName(
 					"org.apache.harmony.xnet.provider.jsse.NativeCrypto")

bramble-android/src/main/java/org/briarproject/bramble/util/AndroidUtils.java

@@ -11,12 +11,15 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
+import java.util.logging.Logger;
 
 import static android.content.Context.MODE_PRIVATE;
-import static android.os.Build.VERSION.SDK_INT;
 
 public class AndroidUtils {
 
+	private static final Logger LOG =
+			Logger.getLogger(AndroidUtils.class.getName());
+
 	// Fake Bluetooth address returned by BluetoothAdapter on API 23 and later
 	private static final String FAKE_BLUETOOTH_ADDRESS = "02:00:00:00:00:00";
 
@@ -25,7 +28,7 @@ public class AndroidUtils {
 	@SuppressWarnings("deprecation")
 	public static Collection<String> getSupportedArchitectures() {
 		List<String> abis = new ArrayList<>();
-		if (SDK_INT >= 21) {
+		if (Build.VERSION.SDK_INT >= 21) {
 			abis.addAll(Arrays.asList(Build.SUPPORTED_ABIS));
 		} else {
 			abis.add(Build.CPU_ABI);

bramble-android/witness.gradle

@@ -31,21 +31,16 @@ dependencyVerification {
         'com.android.tools:sdklib:26.2.1:sdklib-26.2.1.jar:248df7ad5eac4aeb6f96c394c76760de4b7b89ac056e54d0c21a739368b91b45',
         'com.google.code.findbugs:jsr305:1.3.9:jsr305-1.3.9.jar:905721a0eea90a81534abb7ee6ef4ea2e5e645fa1def0a5cd88402df1b46c9ed',
         'com.google.code.gson:gson:2.8.0:gson-2.8.0.jar:c6221763bd79c4f1c3dc7f750b5f29a0bb38b367b81314c4f71896e340c40825',
-        'com.google.dagger:dagger-compiler:2.19:dagger-compiler-2.19.jar:27a4b202a2de908182edb261f8c0a264e08e5e4733d7514bc7fbf0d31da5c0fc',
+        'com.google.dagger:dagger-compiler:2.0.2:dagger-compiler-2.0.2.jar:b74bc9de063dd4c6400b232231f2ef5056145b8fbecbf5382012007dd1c071b3',
-        'com.google.dagger:dagger-producers:2.19:dagger-producers-2.19.jar:a17663abe0fc38b676026950907d4c5f5e2bf338375415861eaff6e3bdb0b768',
+        'com.google.dagger:dagger-producers:2.0-beta:dagger-producers-2.0-beta.jar:99ec15e8a0507ba569e7655bc1165ee5e5ca5aa914b3c8f7e2c2458f724edd6b',
-        'com.google.dagger:dagger-spi:2.19:dagger-spi-2.19.jar:e7a6379d82c841f6aac2866948ad1eed716528707814602842a8d844ce04e2e1',
+        'com.google.dagger:dagger:2.0.2:dagger-2.0.2.jar:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
-        'com.google.dagger:dagger:2.19:dagger-2.19.jar:514b6f1e0727c6572e1d65cb27e4ae668b7aeaeb93a29515182965265b609939',
         'com.google.errorprone:error_prone_annotations:2.0.18:error_prone_annotations-2.0.18.jar:cb4cfad870bf563a07199f3ebea5763f0dec440fcda0b318640b1feaa788656b',
-        'com.google.errorprone:error_prone_annotations:2.1.3:error_prone_annotations-2.1.3.jar:03d0329547c13da9e17c634d1049ea2ead093925e290567e1a364fd6b1fc7ff8',
+        'com.google.guava:guava:18.0:guava-18.0.jar:d664fbfc03d2e5ce9cab2a44fb01f1d0bf9dfebeccc1a473b1f9ea31f79f6f99',
-        'com.google.errorprone:javac-shaded:9-dev-r4023-3:javac-shaded-9-dev-r4023-3.jar:65bfccf60986c47fbc17c9ebab0be626afc41741e0a6ec7109e0768817a36f30',
-        'com.google.googlejavaformat:google-java-format:1.5:google-java-format-1.5.jar:aa19ad7850fb85178aa22f2fddb163b84d6ce4d0035872f30d4408195ca1144e',
         'com.google.guava:guava:23.0:guava-23.0.jar:7baa80df284117e5b945b19b98d367a85ea7b7801bd358ff657946c3bd1b6596',
-        'com.google.guava:guava:25.0-jre:guava-25.0-jre.jar:3fd4341776428c7e0e5c18a7c10de129475b69ab9d30aeafbb5c277bb6074fa9',
         'com.google.j2objc:j2objc-annotations:1.1:j2objc-annotations-1.1.jar:40ceb7157feb263949e0f503fe5f71689333a621021aa20ce0d0acee3badaa0f',
         'com.google.jimfs:jimfs:1.1:jimfs-1.1.jar:c4828e28d7c0a930af9387510b3bada7daa5c04d7c25a75c7b8b081f1c257ddd',
         'com.google.protobuf:protobuf-java:3.4.0:protobuf-java-3.4.0.jar:dce7e66b32456a1b1198da0caff3a8acb71548658391e798c79369241e6490a4',
         'com.googlecode.json-simple:json-simple:1.1:json-simple-1.1.jar:2d9484f4c649f708f47f9a479465fc729770ee65617dca3011836602264f6439',
-        'com.squareup:javapoet:1.11.1:javapoet-1.11.1.jar:9cbf2107be499ec6e95afd36b58e3ca122a24166cdd375732e51267d64058e90',
         'com.squareup:javawriter:2.5.0:javawriter-2.5.0.jar:fcfb09fb0ea0aa97d3cfe7ea792398081348e468f126b3603cb3803f240197f0',
         'com.sun.activation:javax.activation:1.2.0:javax.activation-1.2.0.jar:993302b16cd7056f21e779cc577d175a810bb4900ef73cd8fbf2b50f928ba9ce',
         'com.sun.istack:istack-commons-runtime:2.21:istack-commons-runtime-2.21.jar:c33e67a0807095f02a0e2da139412dd7c4f9cc1a4c054b3e434f96831ba950f4',
@@ -68,9 +63,7 @@ dependencyVerification {
         'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
         'org.bouncycastle:bcpkix-jdk15on:1.56:bcpkix-jdk15on-1.56.jar:7043dee4e9e7175e93e0b36f45b1ec1ecb893c5f755667e8b916eb8dd201c6ca',
         'org.bouncycastle:bcprov-jdk15on:1.56:bcprov-jdk15on-1.56.jar:963e1ee14f808ffb99897d848ddcdb28fa91ddda867eb18d303e82728f878349',
-        'org.briarproject:obfs4proxy-android:0.0.7:obfs4proxy-android-0.0.7.zip:abdfb5d889d848de9bf214f9276abbf454808a505b870819eccc9a9e985bf617',
         'org.briarproject:tor-android:0.3.4.8:tor-android-0.3.4.8.zip:989a0352d9d8d8172cd6c2137654e165e5d2beb10ed1211bab3814e224ad1926',
-        'org.checkerframework:checker-compat-qual:2.5.3:checker-compat-qual-2.5.3.jar:d76b9afea61c7c082908023f0cbc1427fab9abd2df915c8b8a3e7a509bccbc6d',
         'org.codehaus.groovy:groovy-all:2.4.12:groovy-all-2.4.12.jar:6a56af4bd48903d56bec62821876cadefafd007360cc6bd0d8f7aa8d72b38be4',
         'org.codehaus.mojo:animal-sniffer-annotations:1.14:animal-sniffer-annotations-1.14.jar:2068320bd6bad744c3673ab048f67e30bef8f518996fa380033556600669905d',
         'org.glassfish.jaxb:jaxb-core:2.2.11:jaxb-core-2.2.11.jar:37bcaee8ebb04362c8352a5bf6221b86967ecdab5164c696b10b9a2bb587b2aa',

bramble-api/build.gradle

@@ -7,13 +7,15 @@ apply plugin: 'witness'
 apply from: 'witness.gradle'
 
 dependencies {
-	implementation "com.google.dagger:dagger:2.19"
+	implementation "com.google.dagger:dagger:2.0.2"
 	implementation 'com.google.code.findbugs:jsr305:3.0.2'
 
 	testImplementation 'junit:junit:4.12'
 	testImplementation "org.jmock:jmock:2.8.2"
 	testImplementation "org.jmock:jmock-junit4:2.8.2"
 	testImplementation "org.jmock:jmock-legacy:2.8.2"
+	testImplementation "org.hamcrest:hamcrest-library:1.3"
+	testImplementation "org.hamcrest:hamcrest-core:1.3"
 
 	signature 'org.codehaus.mojo.signature:java16:1.1@signature'
 }

bramble-api/src/main/java/org/briarproject/bramble/api/Pair.java

@@ -1,26 +0,0 @@
-package org.briarproject.bramble.api;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.concurrent.Immutable;
-
-@Immutable
-@NotNullByDefault
-public class Pair<A, B> {
-
-	private final A first;
-	private final B second;
-
-	public Pair(A first, B second) {
-		this.first = first;
-		this.second = second;
-	}
-
-	public A getFirst() {
-		return first;
-	}
-
-	public B getSecond() {
-		return second;
-	}
-}

bramble-api/src/main/java/org/briarproject/bramble/api/battery/BatteryManager.java

@@ -1,6 +0,0 @@
-package org.briarproject.bramble.api.battery;
-
-public interface BatteryManager {
-
-	boolean isCharging();
-}

bramble-api/src/main/java/org/briarproject/bramble/api/battery/event/BatteryEvent.java

@@ -1,19 +0,0 @@
-package org.briarproject.bramble.api.battery.event;
-
-import org.briarproject.bramble.api.event.Event;
-
-/**
- * An event that is broadcast when the device starts or stops charging.
- */
-public class BatteryEvent extends Event {
-
-	private final boolean charging;
-
-	public BatteryEvent(boolean charging) {
-		this.charging = charging;
-	}
-
-	public boolean isCharging() {
-		return charging;
-	}
-}

bramble-api/src/main/java/org/briarproject/bramble/api/client/BdfMessageValidator.java

@@ -9,7 +9,7 @@ import org.briarproject.bramble.api.sync.Group;
 import org.briarproject.bramble.api.sync.InvalidMessageException;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageContext;
-import org.briarproject.bramble.api.sync.validation.MessageValidator;
+import org.briarproject.bramble.api.sync.ValidationManager.MessageValidator;
 import org.briarproject.bramble.api.system.Clock;
 
 import java.util.logging.Logger;

bramble-api/src/main/java/org/briarproject/bramble/api/contact/Contact.java

@@ -4,12 +4,8 @@ import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
-import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 
-import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
-import static org.briarproject.bramble.util.StringUtils.toUtf8;
-
 @Immutable
 @NotNullByDefault
 public class Contact {
@@ -17,21 +13,13 @@ public class Contact {
 	private final ContactId id;
 	private final Author author;
 	private final AuthorId localAuthorId;
-	@Nullable
-	private final String alias;
 	private final boolean verified, active;
 
 	public Contact(ContactId id, Author author, AuthorId localAuthorId,
-			@Nullable String alias, boolean verified, boolean active) {
+			boolean verified, boolean active) {
-		if (alias != null) {
-			int aliasLength = toUtf8(alias).length;
-			if (aliasLength == 0 || aliasLength > MAX_AUTHOR_NAME_LENGTH)
-				throw new IllegalArgumentException();
-		}
 		this.id = id;
 		this.author = author;
 		this.localAuthorId = localAuthorId;
-		this.alias = alias;
 		this.verified = verified;
 		this.active = active;
 	}
@@ -48,11 +36,6 @@ public class Contact {
 		return localAuthorId;
 	}
 
-	@Nullable
-	public String getAlias() {
-		return alias;
-	}
-
 	public boolean isVerified() {
 		return verified;
 	}

bramble-api/src/main/java/org/briarproject/bramble/api/contact/ContactManager.java

@@ -5,14 +5,11 @@ import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
-import org.briarproject.bramble.api.identity.AuthorInfo;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.util.Collection;
 
-import javax.annotation.Nullable;
-
 @NotNullByDefault
 public interface ContactManager {
 
@@ -96,18 +93,6 @@ public interface ContactManager {
 	void setContactActive(Transaction txn, ContactId c, boolean active)
 			throws DbException;
 
-	/**
-	 * Sets an alias name for the contact or unsets it if alias is null.
-	 */
-	void setContactAlias(Transaction txn, ContactId c, @Nullable String alias)
-			throws DbException;
-
-	/**
-	 * Sets an alias name for the contact or unsets it if alias is null.
-	 */
-	void setContactAlias(ContactId c, @Nullable String alias)
-			throws DbException;
-
 	/**
 	 * Return true if a contact with this name and public key already exists
 	 */
@@ -120,16 +105,6 @@ public interface ContactManager {
 	boolean contactExists(AuthorId remoteAuthorId, AuthorId localAuthorId)
 			throws DbException;
 
-	/**
-	 * Returns the {@link AuthorInfo} for the given author.
-	 */
-	AuthorInfo getAuthorInfo(AuthorId a) throws DbException;
-
-	/**
-	 * Returns the {@link AuthorInfo} for the given author.
-	 */
-	AuthorInfo getAuthorInfo(Transaction txn, AuthorId a) throws DbException;
-
 	interface ContactHook {
 
 		void addingContact(Transaction txn, Contact c) throws DbException;

bramble-api/src/main/java/org/briarproject/bramble/api/data/BdfStringUtils.java

@@ -1,71 +0,0 @@
-package org.briarproject.bramble.api.data;
-
-import org.briarproject.bramble.api.Bytes;
-import org.briarproject.bramble.api.FormatException;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import java.util.List;
-import java.util.Map;
-import java.util.Map.Entry;
-
-import javax.annotation.Nullable;
-
-import static org.briarproject.bramble.api.data.BdfDictionary.NULL_VALUE;
-import static org.briarproject.bramble.util.StringUtils.toHexString;
-
-@NotNullByDefault
-public class BdfStringUtils {
-
-	public static String toString(@Nullable Object o) throws FormatException {
-		return toString(o, 0);
-	}
-
-	private static String toString(@Nullable Object o, int indent)
-			throws FormatException {
-		if (o == null || o == NULL_VALUE) return "null";
-		if (o instanceof Boolean) return o.toString();
-		if (o instanceof Number) return o.toString();
-		if (o instanceof String) return "\"" + o + "\"";
-		if (o instanceof Bytes)
-			return "x" + toHexString(((Bytes) o).getBytes());
-		if (o instanceof byte[])
-			return "x" + toHexString((byte[]) o);
-		if (o instanceof List) {
-			List<?> list = (List) o;
-			StringBuilder sb = new StringBuilder();
-			sb.append("[\n");
-			int i = 0, size = list.size();
-			for (Object e : list) {
-				indent(sb, indent + 1);
-				sb.append(toString(e, indent + 1));
-				if (i++ < size - 1) sb.append(',');
-				sb.append('\n');
-			}
-			indent(sb, indent);
-			sb.append(']');
-			return sb.toString();
-		}
-		if (o instanceof Map) {
-			Map<?, ?> map = (Map) o;
-			StringBuilder sb = new StringBuilder();
-			sb.append("{\n");
-			int i = 0, size = map.size();
-			for (Entry e : map.entrySet()) {
-				indent(sb, indent + 1);
-				sb.append(toString(e.getKey(), indent + 1));
-				sb.append(": ");
-				sb.append(toString(e.getValue(), indent + 1));
-				if (i++ < size - 1) sb.append(',');
-				sb.append('\n');
-			}
-			indent(sb, indent);
-			sb.append('}');
-			return sb.toString();
-		}
-		throw new FormatException();
-	}
-
-	private static void indent(StringBuilder sb, int indent) {
-		for (int i = 0; i < indent; i++) sb.append('\t');
-	}
-}

bramble-api/src/main/java/org/briarproject/bramble/api/db/DatabaseComponent.java

@@ -19,7 +19,6 @@ import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.sync.MessageStatus;
 import org.briarproject.bramble.api.sync.Offer;
 import org.briarproject.bramble.api.sync.Request;
-import org.briarproject.bramble.api.sync.validation.MessageState;
 import org.briarproject.bramble.api.transport.KeySet;
 import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.TransportKeys;
@@ -29,6 +28,8 @@ import java.util.Map;
 
 import javax.annotation.Nullable;
 
+import static org.briarproject.bramble.api.sync.ValidationManager.State;
+
 /**
  * Encapsulates the database implementation and exposes high-level operations
  * to other components.
@@ -88,14 +89,6 @@ public interface DatabaseComponent {
 	<R, E extends Exception> R transactionWithResult(boolean readOnly,
 			DbCallable<R, E> task) throws DbException, E;
 
-	/**
-	 * Runs the given task within a transaction and returns the result of the
-	 * task, which may be null.
-	 */
-	@Nullable
-	<R, E extends Exception> R transactionWithNullableResult(boolean readOnly,
-			NullableDbCallable<R, E> task) throws DbException, E;
-
 	/**
 	 * Stores a contact associated with the given local and remote pseudonyms,
 	 * and returns an ID for the contact.
@@ -208,24 +201,6 @@ public interface DatabaseComponent {
 	Collection<Message> generateRequestedBatch(Transaction txn, ContactId c,
 			int maxLength, int maxLatency) throws DbException;
 
-	/**
-	 * Returns the number of blocks in the given message.
-	 * <p>
-	 * Read-only.
-	 */
-	int getBlockCount(Transaction txn, MessageId m) throws DbException;
-
-	/**
-	 * Returns the given block of the given message.
-	 * <p>
-	 * Read-only.
-	 *
-	 * @throws NoSuchBlockException if 'blockNumber' is greater than or equal
-	 * to the number of blocks in the message
-	 */
-	byte[] getBlock(Transaction txn, MessageId m, int blockNumber)
-			throws DbException;
-
 	/**
 	 * Returns the contact with the given ID.
 	 * <p/>
@@ -391,12 +366,12 @@ public interface DatabaseComponent {
 	/**
 	 * Returns the IDs and states of all dependencies of the given message.
 	 * For missing dependencies and dependencies in other groups, the state
-	 * {@link MessageState UNKNOWN} is returned.
+	 * {@link State UNKNOWN} is returned.
 	 * <p/>
 	 * Read-only.
 	 */
-	Map<MessageId, MessageState> getMessageDependencies(Transaction txn,
+	Map<MessageId, State> getMessageDependencies(Transaction txn, MessageId m)
-			MessageId m) throws DbException;
+			throws DbException;
 
 	/**
 	 * Returns the IDs and states of all dependents of the given message.
@@ -405,16 +380,15 @@ public interface DatabaseComponent {
 	 * <p/>
 	 * Read-only.
 	 */
-	Map<MessageId, MessageState> getMessageDependents(Transaction txn,
+	Map<MessageId, State> getMessageDependents(Transaction txn, MessageId m)
-			MessageId m) throws DbException;
+			throws DbException;
 
 	/**
 	 * Gets the validation and delivery state of the given message.
 	 * <p/>
 	 * Read-only.
 	 */
-	MessageState getMessageState(Transaction txn, MessageId m)
+	State getMessageState(Transaction txn, MessageId m) throws DbException;
-			throws DbException;
 
 	/**
 	 * Returns the status of the given delivered message with respect to the
@@ -541,12 +515,6 @@ public interface DatabaseComponent {
 	void setContactActive(Transaction txn, ContactId c, boolean active)
 			throws DbException;
 
-	/**
-	 * Sets an alias name for the contact or unsets it if alias is null.
-	 */
-	void setContactAlias(Transaction txn, ContactId c, @Nullable String alias)
-			throws DbException;
-
 	/**
 	 * Sets the given group's visibility to the given contact.
 	 */
@@ -561,7 +529,7 @@ public interface DatabaseComponent {
 	/**
 	 * Sets the validation and delivery state of the given message.
 	 */
-	void setMessageState(Transaction txn, MessageId m, MessageState state)
+	void setMessageState(Transaction txn, MessageId m, State state)
 			throws DbException;
 
 	/**

bramble-api/src/main/java/org/briarproject/bramble/api/db/DbCallable.java

@@ -1,8 +1,5 @@
 package org.briarproject.bramble.api.db;
 
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-@NotNullByDefault
 public interface DbCallable<R, E extends Exception> {
 
 	R call(Transaction txn) throws DbException, E;

bramble-api/src/main/java/org/briarproject/bramble/api/db/DbRunnable.java

@@ -1,8 +1,5 @@
 package org.briarproject.bramble.api.db;
 
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-@NotNullByDefault
 public interface DbRunnable<E extends Exception> {
 
 	void run(Transaction txn) throws DbException, E;

bramble-api/src/main/java/org/briarproject/bramble/api/db/NoSuchBlockException.java

@@ -1,9 +0,0 @@
-package org.briarproject.bramble.api.db;
-
-/**
- * Thrown when a database operation is attempted for a block that is not in
- * the database. This exception may occur due to concurrent updates and does
- * not indicate a database error.
- */
-public class NoSuchBlockException extends DbException {
-}

bramble-api/src/main/java/org/briarproject/bramble/api/db/NullableDbCallable.java

@@ -1,12 +0,0 @@
-package org.briarproject.bramble.api.db;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.Nullable;
-
-@NotNullByDefault
-public interface NullableDbCallable<R, E extends Exception> {
-
-	@Nullable
-	R call(Transaction txn) throws DbException, E;
-}

bramble-api/src/main/java/org/briarproject/bramble/api/identity/Author.java

@@ -16,6 +16,10 @@ import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_K
 @NotNullByDefault
 public class Author implements Nameable {
 
+	public enum Status {
+		NONE, ANONYMOUS, UNKNOWN, UNVERIFIED, VERIFIED, OURSELVES
+	}
+
 	/**
 	 * The current version of the author structure.
 	 */

bramble-api/src/main/java/org/briarproject/bramble/api/identity/AuthorInfo.java

@@ -1,56 +0,0 @@
-package org.briarproject.bramble.api.identity;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.Nullable;
-import javax.annotation.concurrent.Immutable;
-
-@Immutable
-@NotNullByDefault
-public class AuthorInfo {
-
-	public enum Status {
-		NONE, ANONYMOUS, UNKNOWN, UNVERIFIED, VERIFIED, OURSELVES;
-
-		public boolean isContact() {
-			return this == UNVERIFIED || this == VERIFIED;
-		}
-	}
-
-	private final Status status;
-	@Nullable
-	private final String alias;
-
-	public AuthorInfo(Status status, @Nullable String alias) {
-		this.status = status;
-		this.alias = alias;
-	}
-
-	public AuthorInfo(Status status) {
-		this(status, null);
-	}
-
-	public Status getStatus() {
-		return status;
-	}
-
-	@Nullable
-	public String getAlias() {
-		return alias;
-	}
-
-	@Override
-	public int hashCode() {
-		int hashCode = status.ordinal();
-		if (alias != null) hashCode += alias.hashCode();
-		return hashCode;
-	}
-
-	@Override
-	public boolean equals(Object o) {
-		if (!(o instanceof AuthorInfo)) return false;
-		AuthorInfo info = (AuthorInfo) o;
-		return status == info.status &&
-				(alias == null ? info.alias == null : alias.equals(info.alias));
-	}
-}

bramble-api/src/main/java/org/briarproject/bramble/api/identity/IdentityManager.java

@@ -3,6 +3,7 @@ package org.briarproject.bramble.api.identity;
 import org.briarproject.bramble.api.crypto.CryptoExecutor;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.identity.Author.Status;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 @NotNullByDefault
@@ -36,4 +37,14 @@ public interface IdentityManager {
 	 */
 	LocalAuthor getLocalAuthor(Transaction txn) throws DbException;
 
+	/**
+	 * Returns the {@link Status} of the given author.
+	 */
+	Status getAuthorStatus(AuthorId a) throws DbException;
+
+	/**
+	 * Returns the {@link Status} of the given author.
+	 */
+	Status getAuthorStatus(Transaction txn, AuthorId a) throws DbException;
+
 }

bramble-api/src/main/java/org/briarproject/bramble/api/io/BlockSource.java

@@ -1,21 +0,0 @@
-package org.briarproject.bramble.api.io;
-
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.db.NoSuchBlockException;
-import org.briarproject.bramble.api.sync.MessageId;
-
-public interface BlockSource {
-
-	/**
-	 * Returns the number of blocks in the given message.
-	 */
-	int getBlockCount(MessageId m) throws DbException;
-
-	/**
-	 * Returns the given block of the given message.
-	 *
-	 * @throws NoSuchBlockException if 'blockNumber' is greater than or equal
-	 * to the number of blocks in the message
-	 */
-	byte[] getBlock(MessageId m, int blockNumber) throws DbException;
-}

bramble-api/src/main/java/org/briarproject/bramble/api/io/MessageInputStreamFactory.java

@@ -1,17 +0,0 @@
-package org.briarproject.bramble.api.io;
-
-import org.briarproject.bramble.api.sync.MessageId;
-
-import java.io.IOException;
-import java.io.InputStream;
-
-public interface MessageInputStreamFactory {
-
-	/**
-	 * Returns an {@link InputStream} for reading the given message from the
-	 * database. This method returns immediately. If the message is not in the
-	 * database or cannot be read, reading from the stream will throw an
-	 * {@link IOException};
-	 */
-	InputStream getMessageInputStream(MessageId m);
-}

bramble-api/src/main/java/org/briarproject/bramble/api/keyagreement/KeyAgreementConstants.java

@@ -21,7 +21,7 @@ public interface KeyAgreementConstants {
 	/**
 	 * The connection timeout in milliseconds.
 	 */
-	long CONNECTION_TIMEOUT = 60_000;
+	long CONNECTION_TIMEOUT = 20 * 1000;
 
 	/**
 	 * The transport identifier for Bluetooth.

bramble-api/src/main/java/org/briarproject/bramble/api/nullsafety/NullSafety.java

@@ -1,15 +0,0 @@
-package org.briarproject.bramble.api.nullsafety;
-
-import javax.annotation.Nullable;
-
-@NotNullByDefault
-public class NullSafety {
-
-	/**
-	 * Stand-in for `Objects.requireNonNull()`.
-	 */
-	public static <T> T requireNonNull(@Nullable T t) {
-		if (t == null) throw new NullPointerException();
-		return t;
-	}
-}

bramble-api/src/main/java/org/briarproject/bramble/api/sync/SyncConstants.java

@@ -35,9 +35,4 @@ public interface SyncConstants {
 	 * The maximum number of message IDs in an ack, offer or request record.
 	 */
 	int MAX_MESSAGE_IDS = MAX_RECORD_PAYLOAD_BYTES / UniqueId.LENGTH;
-
-	/**
-	 * The maximum length of a message block in bytes.
-	 */
-	int MAX_BLOCK_LENGTH = 32 * 2014; // 32 KiB
 }

bramble-api/src/main/java/org/briarproject/bramble/api/sync/ValidationManager.java

@@ -0,0 +1,87 @@
+package org.briarproject.bramble.api.sync;
+
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.Metadata;
+import org.briarproject.bramble.api.db.Transaction;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+/**
+ * Responsible for managing message validators and passing them messages to
+ * validate.
+ */
+@NotNullByDefault
+public interface ValidationManager {
+
+	enum State {
+
+		UNKNOWN(0), INVALID(1), PENDING(2), DELIVERED(3);
+
+		private final int value;
+
+		State(int value) {
+			this.value = value;
+		}
+
+		public int getValue() {
+			return value;
+		}
+
+		public static State fromValue(int value) {
+			for (State s : values()) if (s.value == value) return s;
+			throw new IllegalArgumentException();
+		}
+	}
+
+	/**
+	 * Registers the message validator for the given client. This method
+	 * should be called before
+	 * {@link LifecycleManager#startServices(SecretKey)}.
+	 */
+	void registerMessageValidator(ClientId c, int majorVersion,
+			MessageValidator v);
+
+	/**
+	 * Registers the incoming message hook for the given client. The hook will
+	 * be called once for each incoming message that passes validation. This
+	 * method should be called before
+	 * {@link LifecycleManager#startServices(SecretKey)}.
+	 */
+	void registerIncomingMessageHook(ClientId c, int majorVersion,
+			IncomingMessageHook hook);
+
+	interface MessageValidator {
+
+		/**
+		 * Validates the given message and returns its metadata and
+		 * dependencies.
+		 */
+		MessageContext validateMessage(Message m, Group g)
+				throws InvalidMessageException;
+	}
+
+	interface IncomingMessageHook {
+
+		/**
+		 * Called once for each incoming message that passes validation.
+		 *
+		 * @return whether or not this message should be shared
+		 * @throws DbException Should only be used for real database errors.
+		 * If this is thrown, delivery will be attempted again at next startup,
+		 * whereas if an InvalidMessageException is thrown,
+		 * the message will be permanently invalidated.
+		 * @throws InvalidMessageException for any non-database error
+		 * that occurs while handling remotely created data.
+		 * This includes errors that occur while handling locally created data
+		 * in a context controlled by remotely created data
+		 * (for example, parsing the metadata of a dependency
+		 * of an incoming message).
+		 * Throwing this will delete the incoming message and its metadata
+		 * marking it as invalid in the database.
+		 * Never rethrow DbException as InvalidMessageException!
+		 */
+		boolean incomingMessage(Transaction txn, Message m, Metadata meta)
+				throws DbException, InvalidMessageException;
+	}
+}

bramble-api/src/main/java/org/briarproject/bramble/api/sync/event/MessageStateChangedEvent.java

@@ -3,10 +3,11 @@ package org.briarproject.bramble.api.sync.event;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.MessageId;
-import org.briarproject.bramble.api.sync.validation.MessageState;
 
 import javax.annotation.concurrent.Immutable;
 
+import static org.briarproject.bramble.api.sync.ValidationManager.State;
+
 /**
  * An event that is broadcast when a message state changed.
  */
@@ -16,10 +17,10 @@ public class MessageStateChangedEvent extends Event {
 
 	private final MessageId messageId;
 	private final boolean local;
-	private final MessageState state;
+	private final State state;
 
 	public MessageStateChangedEvent(MessageId messageId, boolean local,
-			MessageState state) {
+			State state) {
 		this.messageId = messageId;
 		this.local = local;
 		this.state = state;
@@ -33,7 +34,7 @@ public class MessageStateChangedEvent extends Event {
 		return local;
 	}
 
-	public MessageState getState() {
+	public State getState() {
 		return state;
 	}
 

bramble-api/src/main/java/org/briarproject/bramble/api/sync/validation/IncomingMessageHook.java

@@ -1,31 +0,0 @@
-package org.briarproject.bramble.api.sync.validation;
-
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.db.Metadata;
-import org.briarproject.bramble.api.db.Transaction;
-import org.briarproject.bramble.api.sync.InvalidMessageException;
-import org.briarproject.bramble.api.sync.Message;
-
-public interface IncomingMessageHook {
-
-	/**
-	 * Called once for each incoming message that passes validation.
-	 *
-	 * @return whether or not this message should be shared
-	 * @throws DbException Should only be used for real database errors.
-	 * If this is thrown, delivery will be attempted again at next startup,
-	 * whereas if an InvalidMessageException is thrown,
-	 * the message will be permanently invalidated.
-	 * @throws InvalidMessageException for any non-database error
-	 * that occurs while handling remotely created data.
-	 * This includes errors that occur while handling locally created data
-	 * in a context controlled by remotely created data
-	 * (for example, parsing the metadata of a dependency
-	 * of an incoming message).
-	 * Throwing this will delete the incoming message and its metadata
-	 * marking it as invalid in the database.
-	 * Never rethrow DbException as InvalidMessageException!
-	 */
-	boolean incomingMessage(Transaction txn, Message m, Metadata meta)
-			throws DbException, InvalidMessageException;
-}

bramble-api/src/main/java/org/briarproject/bramble/api/sync/validation/MessageState.java

@@ -1,21 +0,0 @@
-package org.briarproject.bramble.api.sync.validation;
-
-public enum MessageState {
-
-	UNKNOWN(0), INVALID(1), PENDING(2), DELIVERED(3);
-
-	private final int value;
-
-	MessageState(int value) {
-		this.value = value;
-	}
-
-	public int getValue() {
-		return value;
-	}
-
-	public static MessageState fromValue(int value) {
-		for (MessageState s : values()) if (s.value == value) return s;
-		throw new IllegalArgumentException();
-	}
-}

bramble-api/src/main/java/org/briarproject/bramble/api/sync/validation/MessageValidator.java

@@ -1,16 +0,0 @@
-package org.briarproject.bramble.api.sync.validation;
-
-import org.briarproject.bramble.api.sync.Group;
-import org.briarproject.bramble.api.sync.InvalidMessageException;
-import org.briarproject.bramble.api.sync.Message;
-import org.briarproject.bramble.api.sync.MessageContext;
-
-public interface MessageValidator {
-
-	/**
-	 * Validates the given message and returns its metadata and
-	 * dependencies.
-	 */
-	MessageContext validateMessage(Message m, Group g)
-			throws InvalidMessageException;
-}

bramble-api/src/main/java/org/briarproject/bramble/api/sync/validation/ValidationManager.java

@@ -1,31 +0,0 @@
-package org.briarproject.bramble.api.sync.validation;
-
-import org.briarproject.bramble.api.crypto.SecretKey;
-import org.briarproject.bramble.api.lifecycle.LifecycleManager;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.sync.ClientId;
-
-/**
- * Responsible for managing message validators and passing them messages to
- * validate.
- */
-@NotNullByDefault
-public interface ValidationManager {
-
-	/**
-	 * Registers the {@link MessageValidator} for the given client. This method
-	 * should be called before
-	 * {@link LifecycleManager#startServices(SecretKey)}.
-	 */
-	void registerMessageValidator(ClientId c, int majorVersion,
-			MessageValidator v);
-
-	/**
-	 * Registers the {@link IncomingMessageHook} for the given client. The hook
-	 * will be called once for each incoming message that passes validation.
-	 * This method should be called before
-	 * {@link LifecycleManager#startServices(SecretKey)}.
-	 */
-	void registerIncomingMessageHook(ClientId c, int majorVersion,
-			IncomingMessageHook hook);
-}

bramble-api/src/main/java/org/briarproject/bramble/util/IoUtils.java

@@ -8,15 +8,12 @@ import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
-import java.net.ServerSocket;
 import java.net.Socket;
-import java.util.logging.Level;
 import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
 
 import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.util.LogUtils.logException;
 
 @NotNullByDefault
 public class IoUtils {
@@ -57,35 +54,16 @@ public class IoUtils {
 			out.flush();
 			out.close();
 		} catch (IOException e) {
-			tryToClose(in, LOG, WARNING);
+			tryToClose(in);
-			tryToClose(out, LOG, WARNING);
+			tryToClose(out);
 		}
 	}
 
-	public static void tryToClose(@Nullable Closeable c, Logger logger,
+	private static void tryToClose(@Nullable Closeable c) {
-			Level level) {
 		try {
 			if (c != null) c.close();
 		} catch (IOException e) {
-			logException(logger, level, e);
+			// We did our best
-		}
-	}
-
-	public static void tryToClose(@Nullable Socket s, Logger logger,
-			Level level) {
-		try {
-			if (s != null) s.close();
-		} catch (IOException e) {
-			logException(logger, level, e);
-		}
-	}
-
-	public static void tryToClose(@Nullable ServerSocket ss, Logger logger,
-			Level level) {
-		try {
-			if (ss != null) ss.close();
-		} catch (IOException e) {
-			logException(logger, level, e);
 		}
 	}
 

bramble-api/src/main/java/org/briarproject/bramble/util/OsUtils.java

@@ -10,6 +10,8 @@ public class OsUtils {
 	@Nullable
 	private static final String os = System.getProperty("os.name");
 	@Nullable
+	private static final String version = System.getProperty("os.version");
+	@Nullable
 	private static final String vendor = System.getProperty("java.vendor");
 
 	public static boolean isWindows() {

bramble-api/src/main/java/org/briarproject/bramble/util/StringUtils.java

@@ -47,7 +47,7 @@ public class StringUtils {
 		try {
 			return s.getBytes("UTF-8");
 		} catch (UnsupportedEncodingException e) {
-			throw new AssertionError(e);
+			throw new RuntimeException(e);
 		}
 	}
 
@@ -63,7 +63,7 @@ public class StringUtils {
 		try {
 			return decoder.decode(buffer).toString();
 		} catch (CharacterCodingException e) {
-			throw new AssertionError(e);
+			throw new RuntimeException(e);
 		}
 	}
 

bramble-api/src/test/java/org/briarproject/bramble/api/identity/AuthorInfoTest.java

@@ -1,42 +0,0 @@
-package org.briarproject.bramble.api.identity;
-
-import org.briarproject.bramble.test.BrambleTestCase;
-import org.junit.Test;
-
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.NONE;
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.VERIFIED;
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotEquals;
-
-public class AuthorInfoTest extends BrambleTestCase {
-
-	@Test
-	public void testEquals() {
-		assertEquals(
-				new AuthorInfo(NONE),
-				new AuthorInfo(NONE, null)
-		);
-		assertEquals(
-				new AuthorInfo(NONE, "test"),
-				new AuthorInfo(NONE, "test")
-		);
-
-		assertNotEquals(
-				new AuthorInfo(NONE),
-				new AuthorInfo(VERIFIED)
-		);
-		assertNotEquals(
-				new AuthorInfo(NONE, "test"),
-				new AuthorInfo(NONE)
-		);
-		assertNotEquals(
-				new AuthorInfo(NONE),
-				new AuthorInfo(NONE, "test")
-		);
-		assertNotEquals(
-				new AuthorInfo(NONE, "a"),
-				new AuthorInfo(NONE, "b")
-		);
-	}
-
-}

bramble-api/witness.gradle

@@ -2,7 +2,7 @@ dependencyVerification {
     verify = [
         'cglib:cglib:3.2.0:cglib-3.2.0.jar:adb13bab79712ad6bdf1bd59f2a3918018a8016e722e8a357065afb9e6690861',
         'com.google.code.findbugs:jsr305:3.0.2:jsr305-3.0.2.jar:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
-        'com.google.dagger:dagger:2.19:dagger-2.19.jar:514b6f1e0727c6572e1d65cb27e4ae668b7aeaeb93a29515182965265b609939',
+        'com.google.dagger:dagger:2.0.2:dagger-2.0.2.jar:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
         'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
         'junit:junit:4.12:junit-4.12.jar:59721f0805e223d84b90677887d9ff567dc534d7c502ca903c0c2b17f05c116a',
         'org.apache.ant:ant-launcher:1.9.4:ant-launcher-1.9.4.jar:7bccea20b41801ca17bcbc909a78c835d0f443f12d639c77bd6ae3d05861608d',

bramble-core/build.gradle

@@ -3,10 +3,10 @@ sourceCompatibility = 1.8
 targetCompatibility = 1.8
 
 apply plugin: 'ru.vyarus.animalsniffer'
+apply plugin: 'net.ltgt.apt'
 apply plugin: 'idea'
 apply plugin: 'witness'
 apply from: 'witness.gradle'
-apply from: '../dagger.gradle'
 
 dependencies {
 	implementation project(path: ':bramble-api', configuration: 'default')
@@ -17,7 +17,7 @@ dependencies {
 	implementation 'org.whispersystems:curve25519-java:0.5.0'
 	implementation 'org.briarproject:jtorctl:0.3'
 
-	annotationProcessor 'com.google.dagger:dagger-compiler:2.19'
+	apt 'com.google.dagger:dagger-compiler:2.0.2'
 
 	testImplementation project(path: ':bramble-api', configuration: 'testOutput')
 	testImplementation 'org.hsqldb:hsqldb:2.3.5' // The last version that supports Java 1.6
@@ -25,8 +25,10 @@ dependencies {
 	testImplementation "org.jmock:jmock:2.8.2"
 	testImplementation "org.jmock:jmock-junit4:2.8.2"
 	testImplementation "org.jmock:jmock-legacy:2.8.2"
+	testImplementation "org.hamcrest:hamcrest-library:1.3"
+	testImplementation "org.hamcrest:hamcrest-core:1.3"
 
-	testAnnotationProcessor 'com.google.dagger:dagger-compiler:2.19'
+	testApt 'com.google.dagger:dagger-compiler:2.0.2'
 
 	signature 'org.codehaus.mojo.signature:java16:1.1@signature'
 }

bramble-core/src/main/java/org/briarproject/bramble/BrambleCoreEagerSingletons.java

@@ -8,7 +8,7 @@ import org.briarproject.bramble.lifecycle.LifecycleModule;
 import org.briarproject.bramble.plugin.PluginModule;
 import org.briarproject.bramble.properties.PropertiesModule;
 import org.briarproject.bramble.reporting.ReportingModule;
-import org.briarproject.bramble.sync.validation.ValidationModule;
+import org.briarproject.bramble.sync.SyncModule;
 import org.briarproject.bramble.system.SystemModule;
 import org.briarproject.bramble.transport.TransportModule;
 import org.briarproject.bramble.versioning.VersioningModule;
@@ -31,11 +31,11 @@ public interface BrambleCoreEagerSingletons {
 
 	void inject(ReportingModule.EagerSingletons init);
 
+	void inject(SyncModule.EagerSingletons init);
+
 	void inject(SystemModule.EagerSingletons init);
 
 	void inject(TransportModule.EagerSingletons init);
 
-	void inject(ValidationModule.EagerSingletons init);
-
 	void inject(VersioningModule.EagerSingletons init);
 }

bramble-core/src/main/java/org/briarproject/bramble/BrambleCoreModule.java

@@ -9,7 +9,6 @@ import org.briarproject.bramble.db.DatabaseExecutorModule;
 import org.briarproject.bramble.db.DatabaseModule;
 import org.briarproject.bramble.event.EventModule;
 import org.briarproject.bramble.identity.IdentityModule;
-import org.briarproject.bramble.io.IoModule;
 import org.briarproject.bramble.keyagreement.KeyAgreementModule;
 import org.briarproject.bramble.lifecycle.LifecycleModule;
 import org.briarproject.bramble.plugin.PluginModule;
@@ -20,7 +19,6 @@ import org.briarproject.bramble.reporting.ReportingModule;
 import org.briarproject.bramble.settings.SettingsModule;
 import org.briarproject.bramble.socks.SocksModule;
 import org.briarproject.bramble.sync.SyncModule;
-import org.briarproject.bramble.sync.validation.ValidationModule;
 import org.briarproject.bramble.system.SystemModule;
 import org.briarproject.bramble.transport.TransportModule;
 import org.briarproject.bramble.versioning.VersioningModule;
@@ -37,7 +35,6 @@ import dagger.Module;
 		DatabaseExecutorModule.class,
 		EventModule.class,
 		IdentityModule.class,
-		IoModule.class,
 		KeyAgreementModule.class,
 		LifecycleModule.class,
 		PluginModule.class,
@@ -50,7 +47,6 @@ import dagger.Module;
 		SyncModule.class,
 		SystemModule.class,
 		TransportModule.class,
-		ValidationModule.class,
 		VersioningModule.class
 })
 public class BrambleCoreModule {
@@ -64,9 +60,9 @@ public class BrambleCoreModule {
 		c.inject(new PluginModule.EagerSingletons());
 		c.inject(new PropertiesModule.EagerSingletons());
 		c.inject(new ReportingModule.EagerSingletons());
+		c.inject(new SyncModule.EagerSingletons());
 		c.inject(new SystemModule.EagerSingletons());
 		c.inject(new TransportModule.EagerSingletons());
-		c.inject(new ValidationModule.EagerSingletons());
 		c.inject(new VersioningModule.EagerSingletons());
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/battery/DefaultBatteryManagerModule.java

@@ -1,19 +0,0 @@
-package org.briarproject.bramble.battery;
-
-import org.briarproject.bramble.api.battery.BatteryManager;
-
-import dagger.Module;
-import dagger.Provides;
-
-/**
- * Provides a default implementation of {@link BatteryManager} for systems
- * without batteries.
- */
-@Module
-public class DefaultBatteryManagerModule {
-
-	@Provides
-	BatteryManager provideBatteryManager() {
-		return () -> false;
-	}
-}

bramble-core/src/main/java/org/briarproject/bramble/client/ClientHelperImpl.java

@@ -82,7 +82,13 @@ class ClientHelperImpl implements ClientHelper {
 	@Override
 	public void addLocalMessage(Message m, BdfDictionary metadata,
 			boolean shared) throws DbException, FormatException {
-		db.transaction(false, txn -> addLocalMessage(txn, m, metadata, shared));
+		Transaction txn = db.startTransaction(false);
+		try {
+			addLocalMessage(txn, m, metadata, shared);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
 	}
 
 	@Override
@@ -107,7 +113,15 @@ class ClientHelperImpl implements ClientHelper {
 
 	@Override
 	public Message getMessage(MessageId m) throws DbException {
-		return db.transactionWithResult(true, txn -> getMessage(txn, m));
+		Message message;
+		Transaction txn = db.startTransaction(true);
+		try {
+			message = getMessage(txn, m);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
+		return message;
 	}
 
 	@Override
@@ -118,7 +132,15 @@ class ClientHelperImpl implements ClientHelper {
 	@Override
 	public BdfList getMessageAsList(MessageId m) throws DbException,
 			FormatException {
-		return db.transactionWithResult(true, txn -> getMessageAsList(txn, m));
+		BdfList list;
+		Transaction txn = db.startTransaction(true);
+		try {
+			list = getMessageAsList(txn, m);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
+		return list;
 	}
 
 	@Override
@@ -130,8 +152,15 @@ class ClientHelperImpl implements ClientHelper {
 	@Override
 	public BdfDictionary getGroupMetadataAsDictionary(GroupId g)
 			throws DbException, FormatException {
-		return db.transactionWithResult(true, txn ->
+		BdfDictionary dictionary;
-				getGroupMetadataAsDictionary(txn, g));
+		Transaction txn = db.startTransaction(true);
+		try {
+			dictionary = getGroupMetadataAsDictionary(txn, g);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
+		return dictionary;
 	}
 
 	@Override
@@ -144,8 +173,15 @@ class ClientHelperImpl implements ClientHelper {
 	@Override
 	public BdfDictionary getMessageMetadataAsDictionary(MessageId m)
 			throws DbException, FormatException {
-		return db.transactionWithResult(true, txn ->
+		BdfDictionary dictionary;
-				getMessageMetadataAsDictionary(txn, m));
+		Transaction txn = db.startTransaction(true);
+		try {
+			dictionary = getMessageMetadataAsDictionary(txn, m);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
+		return dictionary;
 	}
 
 	@Override
@@ -158,8 +194,15 @@ class ClientHelperImpl implements ClientHelper {
 	@Override
 	public Map<MessageId, BdfDictionary> getMessageMetadataAsDictionary(
 			GroupId g) throws DbException, FormatException {
-		return db.transactionWithResult(true, txn ->
+		Map<MessageId, BdfDictionary> map;
-				getMessageMetadataAsDictionary(txn, g));
+		Transaction txn = db.startTransaction(true);
+		try {
+			map = getMessageMetadataAsDictionary(txn, g);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
+		return map;
 	}
 
 	@Override
@@ -176,8 +219,15 @@ class ClientHelperImpl implements ClientHelper {
 	public Map<MessageId, BdfDictionary> getMessageMetadataAsDictionary(
 			GroupId g, BdfDictionary query) throws DbException,
 			FormatException {
-		return db.transactionWithResult(true, txn ->
+		Map<MessageId, BdfDictionary> map;
-				getMessageMetadataAsDictionary(txn, g, query));
+		Transaction txn = db.startTransaction(true);
+		try {
+			map = getMessageMetadataAsDictionary(txn, g, query);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
+		return map;
 	}
 
 	@Override
@@ -195,7 +245,13 @@ class ClientHelperImpl implements ClientHelper {
 	@Override
 	public void mergeGroupMetadata(GroupId g, BdfDictionary metadata)
 			throws DbException, FormatException {
-		db.transaction(false, txn -> mergeGroupMetadata(txn, g, metadata));
+		Transaction txn = db.startTransaction(false);
+		try {
+			mergeGroupMetadata(txn, g, metadata);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
 	}
 
 	@Override
@@ -207,7 +263,13 @@ class ClientHelperImpl implements ClientHelper {
 	@Override
 	public void mergeMessageMetadata(MessageId m, BdfDictionary metadata)
 			throws DbException, FormatException {
-		db.transaction(false, txn -> mergeMessageMetadata(txn, m, metadata));
+		Transaction txn = db.startTransaction(false);
+		try {
+			mergeMessageMetadata(txn, m, metadata);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
 	}
 
 	@Override

bramble-core/src/main/java/org/briarproject/bramble/contact/ContactExchangeTaskImpl.java

@@ -13,6 +13,7 @@ import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.db.ContactExistsException;
 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.identity.Author;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
@@ -157,8 +158,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 				streamWriterFactory.createContactExchangeStreamWriter(out,
 						alice ? aliceHeaderKey : bobHeaderKey);
 		RecordWriter recordWriter =
-				recordWriterFactory
+				recordWriterFactory.createRecordWriter(streamWriter.getOutputStream());
-						.createRecordWriter(streamWriter.getOutputStream());
 
 		// Derive the nonces to be signed
 		byte[] aliceNonce = crypto.mac(ALICE_NONCE_LABEL, masterSecret,
@@ -287,14 +287,19 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 	private ContactId addContact(Author remoteAuthor, long timestamp,
 			Map<TransportId, TransportProperties> remoteProperties)
 			throws DbException {
-		return db.transactionWithResult(false, txn -> {
+		ContactId contactId;
-			ContactId contactId = contactManager.addContact(txn, remoteAuthor,
+		Transaction txn = db.startTransaction(false);
+		try {
+			contactId = contactManager.addContact(txn, remoteAuthor,
 					localAuthor.getId(), masterSecret, timestamp, alice,
 					true, true);
 			transportPropertyManager.addRemoteProperties(txn, contactId,
 					remoteProperties);
-			return contactId;
+			db.commitTransaction(txn);
-		});
+		} finally {
+			db.endTransaction(txn);
+		}
+		return contactId;
 	}
 
 	private void tryToClose(DuplexTransportConnection conn) {

bramble-core/src/main/java/org/briarproject/bramble/contact/ContactManagerImpl.java

@@ -10,9 +10,6 @@ import org.briarproject.bramble.api.db.NoSuchContactException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
-import org.briarproject.bramble.api.identity.AuthorInfo;
-import org.briarproject.bramble.api.identity.IdentityManager;
-import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.transport.KeyManager;
 
@@ -21,32 +18,21 @@ import java.util.Collection;
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;
 
-import javax.annotation.Nullable;
 import javax.annotation.concurrent.ThreadSafe;
 import javax.inject.Inject;
 
-import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.OURSELVES;
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.UNKNOWN;
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.UNVERIFIED;
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.VERIFIED;
-import static org.briarproject.bramble.util.StringUtils.toUtf8;
-
 @ThreadSafe
 @NotNullByDefault
 class ContactManagerImpl implements ContactManager {
 
 	private final DatabaseComponent db;
 	private final KeyManager keyManager;
-	private final IdentityManager identityManager;
 	private final List<ContactHook> hooks;
 
 	@Inject
-	ContactManagerImpl(DatabaseComponent db, KeyManager keyManager,
+	ContactManagerImpl(DatabaseComponent db, KeyManager keyManager) {
-			IdentityManager identityManager) {
 		this.db = db;
 		this.keyManager = keyManager;
-		this.identityManager = identityManager;
 		hooks = new CopyOnWriteArrayList<>();
 	}
 
@@ -79,21 +65,42 @@ class ContactManagerImpl implements ContactManager {
 	public ContactId addContact(Author remote, AuthorId local, SecretKey master,
 			long timestamp, boolean alice, boolean verified, boolean active)
 			throws DbException {
-		return db.transactionWithResult(false, txn ->
+		ContactId c;
-				addContact(txn, remote, local, master, timestamp, alice,
+		Transaction txn = db.startTransaction(false);
-						verified, active));
+		try {
+			c = addContact(txn, remote, local, master, timestamp, alice,
+					verified, active);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
+		return c;
 	}
 
 	@Override
 	public Contact getContact(ContactId c) throws DbException {
-		return db.transactionWithResult(true, txn -> db.getContact(txn, c));
+		Contact contact;
+		Transaction txn = db.startTransaction(true);
+		try {
+			contact = db.getContact(txn, c);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
+		return contact;
 	}
 
 	@Override
 	public Contact getContact(AuthorId remoteAuthorId, AuthorId localAuthorId)
 			throws DbException {
-		return db.transactionWithResult(true, txn ->
+		Transaction txn = db.startTransaction(true);
-				getContact(txn, remoteAuthorId, localAuthorId));
+		try {
+			Contact c = getContact(txn, remoteAuthorId, localAuthorId);
+			db.commitTransaction(txn);
+			return c;
+		} finally {
+			db.endTransaction(txn);
+		}
 	}
 
 	@Override
@@ -111,8 +118,14 @@ class ContactManagerImpl implements ContactManager {
 
 	@Override
 	public Collection<Contact> getActiveContacts() throws DbException {
-		Collection<Contact> contacts =
+		Collection<Contact> contacts;
-				db.transactionWithResult(true, db::getContacts);
+		Transaction txn = db.startTransaction(true);
+		try {
+			contacts = db.getContacts(txn);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
 		List<Contact> active = new ArrayList<>(contacts.size());
 		for (Contact c : contacts) if (c.isActive()) active.add(c);
 		return active;
@@ -120,7 +133,13 @@ class ContactManagerImpl implements ContactManager {
 
 	@Override
 	public void removeContact(ContactId c) throws DbException {
-		db.transaction(false, txn -> removeContact(txn, c));
+		Transaction txn = db.startTransaction(false);
+		try {
+			removeContact(txn, c);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
 	}
 
 	@Override
@@ -129,23 +148,6 @@ class ContactManagerImpl implements ContactManager {
 		db.setContactActive(txn, c, active);
 	}
 
-	@Override
-	public void setContactAlias(Transaction txn, ContactId c,
-			@Nullable String alias) throws DbException {
-		if (alias != null) {
-			int aliasLength = toUtf8(alias).length;
-			if (aliasLength == 0 || aliasLength > MAX_AUTHOR_NAME_LENGTH)
-				throw new IllegalArgumentException();
-		}
-		db.setContactAlias(txn, c, alias);
-	}
-
-	@Override
-	public void setContactAlias(ContactId c, @Nullable String alias)
-			throws DbException {
-		db.transaction(false, txn -> setContactAlias(txn, c, alias));
-	}
-
 	@Override
 	public boolean contactExists(Transaction txn, AuthorId remoteAuthorId,
 			AuthorId localAuthorId) throws DbException {
@@ -155,8 +157,15 @@ class ContactManagerImpl implements ContactManager {
 	@Override
 	public boolean contactExists(AuthorId remoteAuthorId,
 			AuthorId localAuthorId) throws DbException {
-		return db.transactionWithResult(true, txn ->
+		boolean exists;
-				contactExists(txn, remoteAuthorId, localAuthorId));
+		Transaction txn = db.startTransaction(true);
+		try {
+			exists = contactExists(txn, remoteAuthorId, localAuthorId);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
+		return exists;
 	}
 
 	@Override
@@ -167,23 +176,4 @@ class ContactManagerImpl implements ContactManager {
 		db.removeContact(txn, c);
 	}
 
-	@Override
-	public AuthorInfo getAuthorInfo(AuthorId a) throws DbException {
-		return db.transactionWithResult(true, txn -> getAuthorInfo(txn, a));
-	}
-
-	@Override
-	public AuthorInfo getAuthorInfo(Transaction txn, AuthorId authorId)
-			throws DbException {
-		LocalAuthor localAuthor = identityManager.getLocalAuthor(txn);
-		if (localAuthor.getId().equals(authorId))
-			return new AuthorInfo(OURSELVES);
-		Collection<Contact> contacts = db.getContactsByAuthorId(txn, authorId);
-		if (contacts.isEmpty()) return new AuthorInfo(UNKNOWN);
-		if (contacts.size() > 1) throw new AssertionError();
-		Contact c = contacts.iterator().next();
-		if (c.isVerified()) return new AuthorInfo(VERIFIED, c.getAlias());
-		else return new AuthorInfo(UNVERIFIED, c.getAlias());
-	}
-
 }

bramble-core/src/main/java/org/briarproject/bramble/data/BdfReaderImpl.java

@@ -29,7 +29,6 @@ import static org.briarproject.bramble.data.Types.STRING_16;
 import static org.briarproject.bramble.data.Types.STRING_32;
 import static org.briarproject.bramble.data.Types.STRING_8;
 import static org.briarproject.bramble.data.Types.TRUE;
-import static org.briarproject.bramble.util.StringUtils.fromUtf8;
 
 @NotThreadSafe
 @NotNullByDefault
@@ -254,7 +253,7 @@ class BdfReaderImpl implements BdfReader {
 		if (length < 0 || length > maxBufferSize) throw new FormatException();
 		if (length == 0) return "";
 		readIntoBuffer(length);
-		return fromUtf8(buf, 0, length);
+		return new String(buf, 0, length, "UTF-8");
 	}
 
 	private int readStringLength() throws IOException {

bramble-core/src/main/java/org/briarproject/bramble/db/BlockSourceImpl.java

@@ -1,29 +0,0 @@
-package org.briarproject.bramble.db;
-
-import org.briarproject.bramble.api.db.DatabaseComponent;
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.io.BlockSource;
-import org.briarproject.bramble.api.sync.MessageId;
-
-import javax.inject.Inject;
-
-class BlockSourceImpl implements BlockSource {
-
-	private final DatabaseComponent db;
-
-	@Inject
-	BlockSourceImpl(DatabaseComponent db) {
-		this.db = db;
-	}
-
-	@Override
-	public int getBlockCount(MessageId m) throws DbException {
-		return db.transactionWithResult(true, txn -> db.getBlockCount(txn, m));
-	}
-
-	@Override
-	public byte[] getBlock(MessageId m, int blockNumber) throws DbException {
-		return db.transactionWithResult(true, txn ->
-				db.getBlock(txn, m, blockNumber));
-	}
-}

bramble-core/src/main/java/org/briarproject/bramble/db/Database.java

@@ -22,7 +22,7 @@ import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.sync.MessageStatus;
-import org.briarproject.bramble.api.sync.validation.MessageState;
+import org.briarproject.bramble.api.sync.ValidationManager.State;
 import org.briarproject.bramble.api.transport.KeySet;
 import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.TransportKeys;
@@ -106,7 +106,7 @@ interface Database<T> {
 	 * @param sender the contact from whom the message was received, or null
 	 * if the message was created locally.
 	 */
-	void addMessage(T txn, Message m, MessageState state, boolean shared,
+	void addMessage(T txn, Message m, State state, boolean shared,
 			@Nullable ContactId sender) throws DbException;
 
 	/**
@@ -114,7 +114,7 @@ interface Database<T> {
 	 * in the given state.
 	 */
 	void addMessageDependency(T txn, Message dependent, MessageId dependency,
-			MessageState dependentState) throws DbException;
+			State dependentState) throws DbException;
 
 	/**
 	 * Records that a message has been offered by the given contact.
@@ -310,11 +310,11 @@ interface Database<T> {
 	/**
 	 * Returns the IDs and states of all dependencies of the given message.
 	 * For missing dependencies and dependencies in other groups, the state
-	 * {@link MessageState UNKNOWN} is returned.
+	 * {@link State UNKNOWN} is returned.
 	 * <p/>
 	 * Read-only.
 	 */
-	Map<MessageId, MessageState> getMessageDependencies(T txn, MessageId m)
+	Map<MessageId, State> getMessageDependencies(T txn, MessageId m)
 			throws DbException;
 
 	/**
@@ -324,7 +324,7 @@ interface Database<T> {
 	 * <p/>
 	 * Read-only.
 	 */
-	Map<MessageId, MessageState> getMessageDependents(T txn, MessageId m)
+	Map<MessageId, State> getMessageDependents(T txn, MessageId m)
 			throws DbException;
 
 	/**
@@ -383,7 +383,7 @@ interface Database<T> {
 	 * <p/>
 	 * Read-only.
 	 */
-	MessageState getMessageState(T txn, MessageId m) throws DbException;
+	State getMessageState(T txn, MessageId m) throws DbException;
 
 	/**
 	 * Returns the status of all delivered messages in the given group with
@@ -616,12 +616,6 @@ interface Database<T> {
 	void setContactActive(T txn, ContactId c, boolean active)
 			throws DbException;
 
-	/**
-	 * Sets an alias name for a contact.
-	 */
-	void setContactAlias(T txn, ContactId c, @Nullable String alias)
-			throws DbException;
-
 	/**
 	 * Sets the given group's visibility to the given contact to either
 	 * {@link Visibility VISIBLE} or {@link Visibility SHARED}.
@@ -637,8 +631,7 @@ interface Database<T> {
 	/**
 	 * Sets the validation and delivery state of the given message.
 	 */
-	void setMessageState(T txn, MessageId m, MessageState state)
+	void setMessageState(T txn, MessageId m, State state) throws DbException;
-			throws DbException;
 
 	/**
 	 * Sets the reordering window for the given key set and transport in the

bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseComponentImpl.java

@@ -14,13 +14,11 @@ import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.DbRunnable;
 import org.briarproject.bramble.api.db.Metadata;
 import org.briarproject.bramble.api.db.MigrationListener;
-import org.briarproject.bramble.api.db.NoSuchBlockException;
 import org.briarproject.bramble.api.db.NoSuchContactException;
 import org.briarproject.bramble.api.db.NoSuchGroupException;
 import org.briarproject.bramble.api.db.NoSuchLocalAuthorException;
 import org.briarproject.bramble.api.db.NoSuchMessageException;
 import org.briarproject.bramble.api.db.NoSuchTransportException;
-import org.briarproject.bramble.api.db.NullableDbCallable;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
@@ -44,6 +42,7 @@ import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.api.sync.MessageStatus;
 import org.briarproject.bramble.api.sync.Offer;
 import org.briarproject.bramble.api.sync.Request;
+import org.briarproject.bramble.api.sync.ValidationManager.State;
 import org.briarproject.bramble.api.sync.event.GroupAddedEvent;
 import org.briarproject.bramble.api.sync.event.GroupRemovedEvent;
 import org.briarproject.bramble.api.sync.event.GroupVisibilityUpdatedEvent;
@@ -55,7 +54,6 @@ import org.briarproject.bramble.api.sync.event.MessageToAckEvent;
 import org.briarproject.bramble.api.sync.event.MessageToRequestEvent;
 import org.briarproject.bramble.api.sync.event.MessagesAckedEvent;
 import org.briarproject.bramble.api.sync.event.MessagesSentEvent;
-import org.briarproject.bramble.api.sync.validation.MessageState;
 import org.briarproject.bramble.api.transport.KeySet;
 import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.TransportKeys;
@@ -76,8 +74,8 @@ import javax.inject.Inject;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.api.sync.Group.Visibility.INVISIBLE;
 import static org.briarproject.bramble.api.sync.Group.Visibility.SHARED;
-import static org.briarproject.bramble.api.sync.validation.MessageState.DELIVERED;
+import static org.briarproject.bramble.api.sync.ValidationManager.State.DELIVERED;
-import static org.briarproject.bramble.api.sync.validation.MessageState.UNKNOWN;
+import static org.briarproject.bramble.api.sync.ValidationManager.State.UNKNOWN;
 import static org.briarproject.bramble.db.DatabaseConstants.MAX_OFFERED_MESSAGES;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.logException;
@@ -195,20 +193,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		}
 	}
 
-	@Override
-	public <R, E extends Exception> R transactionWithNullableResult(
-			boolean readOnly, NullableDbCallable<R, E> task)
-			throws DbException, E {
-		Transaction txn = startTransaction(readOnly);
-		try {
-			R result = task.call(txn);
-			commitTransaction(txn);
-			return result;
-		} finally {
-			endTransaction(txn);
-		}
-	}
-
 	private T unbox(Transaction transaction) {
 		if (transaction.isCommitted()) throw new IllegalStateException();
 		return txnClass.cast(transaction.unbox());
@@ -421,26 +405,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return messages;
 	}
 
-	@Override
-	public int getBlockCount(Transaction transaction, MessageId m)
-			throws DbException {
-		T txn = unbox(transaction);
-		if (!db.containsMessage(txn, m))
-			throw new NoSuchMessageException();
-		return 1;
-	}
-
-	@Override
-	public byte[] getBlock(Transaction transaction, MessageId m,
-			int blockNumber) throws DbException {
-		T txn = unbox(transaction);
-		if (!db.containsMessage(txn, m))
-			throw new NoSuchMessageException();
-		if (blockNumber != 0)
-			throw new NoSuchBlockException();
-		return db.getMessage(txn, m).getBody();
-	}
-
 	@Override
 	public Contact getContact(Transaction transaction, ContactId c)
 			throws DbException {
@@ -600,7 +564,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public MessageState getMessageState(Transaction transaction, MessageId m)
+	public State getMessageState(Transaction transaction, MessageId m)
 			throws DbException {
 		T txn = unbox(transaction);
 		if (!db.containsMessage(txn, m))
@@ -640,8 +604,8 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public Map<MessageId, MessageState> getMessageDependencies(
+	public Map<MessageId, State> getMessageDependencies(Transaction transaction,
-			Transaction transaction, MessageId m) throws DbException {
+			MessageId m) throws DbException {
 		T txn = unbox(transaction);
 		if (!db.containsMessage(txn, m))
 			throw new NoSuchMessageException();
@@ -649,8 +613,8 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public Map<MessageId, MessageState> getMessageDependents(
+	public Map<MessageId, State> getMessageDependents(Transaction transaction,
-			Transaction transaction, MessageId m) throws DbException {
+			MessageId m) throws DbException {
 		T txn = unbox(transaction);
 		if (!db.containsMessage(txn, m))
 			throw new NoSuchMessageException();
@@ -895,16 +859,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		transaction.attach(new ContactStatusChangedEvent(c, active));
 	}
 
-	@Override
-	public void setContactAlias(Transaction transaction, ContactId c,
-			@Nullable String alias) throws DbException {
-		if (transaction.isReadOnly()) throw new IllegalArgumentException();
-		T txn = unbox(transaction);
-		if (!db.containsContact(txn, c))
-			throw new NoSuchContactException();
-		db.setContactAlias(txn, c, alias);
-	}
-
 	@Override
 	public void setGroupVisibility(Transaction transaction, ContactId c,
 			GroupId g, Visibility v) throws DbException {
@@ -939,7 +893,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 
 	@Override
 	public void setMessageState(Transaction transaction, MessageId m,
-			MessageState state) throws DbException {
+			State state) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
 		if (!db.containsMessage(txn, m))
@@ -956,10 +910,10 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		T txn = unbox(transaction);
 		if (!db.containsMessage(txn, dependent.getId()))
 			throw new NoSuchMessageException();
-		MessageState dependentState =
+		State dependentState = db.getMessageState(txn, dependent.getId());
-				db.getMessageState(txn, dependent.getId());
 		for (MessageId dependency : dependencies) {
-			db.addMessageDependency(txn, dependent, dependency, dependentState);
+			db.addMessageDependency(txn, dependent, dependency,
+					dependentState);
 		}
 	}
 

bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseModule.java

@@ -3,7 +3,6 @@ package org.briarproject.bramble.db;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DatabaseConfig;
 import org.briarproject.bramble.api.event.EventBus;
-import org.briarproject.bramble.api.io.BlockSource;
 import org.briarproject.bramble.api.lifecycle.ShutdownManager;
 import org.briarproject.bramble.api.sync.MessageFactory;
 import org.briarproject.bramble.api.system.Clock;
@@ -32,9 +31,4 @@ public class DatabaseModule {
 		return new DatabaseComponentImpl<>(db, Connection.class, eventBus,
 				shutdown);
 	}
-
-	@Provides
-	BlockSource provideBlockSource(BlockSourceImpl blockSource) {
-		return blockSource;
-	}
 }

bramble-core/src/main/java/org/briarproject/bramble/db/DatabaseTypes.java

@@ -1,34 +0,0 @@
-package org.briarproject.bramble.db;
-
-class DatabaseTypes {
-
-	private final String hashType, secretType, binaryType;
-	private final String counterType, stringType;
-
-	public DatabaseTypes(String hashType, String secretType, String binaryType,
-			String counterType, String stringType) {
-		this.hashType = hashType;
-		this.secretType = secretType;
-		this.binaryType = binaryType;
-		this.counterType = counterType;
-		this.stringType = stringType;
-	}
-
-	/**
-	 * Replaces database type placeholders in a statement with the actual types.
-	 * These placeholders are currently supported:
-	 * <li> _HASH
-	 * <li> _SECRET
-	 * <li> _BINARY
-	 * <li> _COUNTER
-	 * <li> _STRING
-	 */
-	String replaceTypes(String s) {
-		s = s.replaceAll("_HASH", hashType);
-		s = s.replaceAll("_SECRET", secretType);
-		s = s.replaceAll("_BINARY", binaryType);
-		s = s.replaceAll("_COUNTER", counterType);
-		s = s.replaceAll("_STRING", stringType);
-		return s;
-	}
-}

bramble-core/src/main/java/org/briarproject/bramble/db/H2Database.java

@@ -15,30 +15,21 @@ import java.sql.DriverManager;
 import java.sql.SQLException;
 import java.sql.Statement;
 import java.util.Properties;
-import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
 import javax.inject.Inject;
 
-import static java.util.logging.Level.WARNING;
-import static java.util.logging.Logger.getLogger;
-import static org.briarproject.bramble.db.JdbcUtils.tryToClose;
-
 /**
  * Contains all the H2-specific code for the database.
  */
 @NotNullByDefault
 class H2Database extends JdbcDatabase {
 
-	private static final Logger LOG = getLogger(H2Database.class.getName());
-
 	private static final String HASH_TYPE = "BINARY(32)";
 	private static final String SECRET_TYPE = "BINARY(32)";
 	private static final String BINARY_TYPE = "BINARY";
 	private static final String COUNTER_TYPE = "INT NOT NULL AUTO_INCREMENT";
 	private static final String STRING_TYPE = "VARCHAR";
-	private static final DatabaseTypes dbTypes = new DatabaseTypes(HASH_TYPE,
-			SECRET_TYPE, BINARY_TYPE, COUNTER_TYPE, STRING_TYPE);
 
 	private final DatabaseConfig config;
 	private final String url;
@@ -49,7 +40,8 @@ class H2Database extends JdbcDatabase {
 	@Inject
 	H2Database(DatabaseConfig config, MessageFactory messageFactory,
 			Clock clock) {
-		super(dbTypes, messageFactory, clock);
+		super(HASH_TYPE, SECRET_TYPE, BINARY_TYPE, COUNTER_TYPE, STRING_TYPE,
+				messageFactory, clock);
 		this.config = config;
 		File dir = config.getDatabaseDirectory();
 		String path = new File(dir, "db").getAbsolutePath();
@@ -128,8 +120,8 @@ class H2Database extends JdbcDatabase {
 			s.close();
 			c.close();
 		} catch (SQLException e) {
-			tryToClose(s, LOG, WARNING);
+			tryToClose(s);
-			tryToClose(c, LOG, WARNING);
+			tryToClose(c);
 			throw new DbException(e);
 		}
 	}

bramble-core/src/main/java/org/briarproject/bramble/db/HyperSqlDatabase.java

@@ -14,32 +14,22 @@ import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.SQLException;
 import java.sql.Statement;
-import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
 import javax.inject.Inject;
 
-import static java.util.logging.Level.WARNING;
-import static java.util.logging.Logger.getLogger;
-import static org.briarproject.bramble.db.JdbcUtils.tryToClose;
-
 /**
  * Contains all the HSQLDB-specific code for the database.
  */
 @NotNullByDefault
 class HyperSqlDatabase extends JdbcDatabase {
 
-	private static final Logger LOG =
-			getLogger(HyperSqlDatabase.class.getName());
-
 	private static final String HASH_TYPE = "BINARY(32)";
 	private static final String SECRET_TYPE = "BINARY(32)";
 	private static final String BINARY_TYPE = "BINARY";
 	private static final String COUNTER_TYPE =
 			"INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY(START WITH 1)";
 	private static final String STRING_TYPE = "VARCHAR";
-	private static final DatabaseTypes dbTypes = new DatabaseTypes(HASH_TYPE,
-			SECRET_TYPE, BINARY_TYPE, COUNTER_TYPE, STRING_TYPE);
 
 	private final DatabaseConfig config;
 	private final String url;
@@ -50,7 +40,8 @@ class HyperSqlDatabase extends JdbcDatabase {
 	@Inject
 	HyperSqlDatabase(DatabaseConfig config, MessageFactory messageFactory,
 			Clock clock) {
-		super(dbTypes, messageFactory, clock);
+		super(HASH_TYPE, SECRET_TYPE, BINARY_TYPE, COUNTER_TYPE, STRING_TYPE,
+				messageFactory, clock);
 		this.config = config;
 		File dir = config.getDatabaseDirectory();
 		String path = new File(dir, "db").getAbsolutePath();
@@ -80,14 +71,14 @@ class HyperSqlDatabase extends JdbcDatabase {
 			s.close();
 			c.close();
 		} catch (SQLException e) {
-			tryToClose(s, LOG, WARNING);
+			tryToClose(s);
-			tryToClose(c, LOG, WARNING);
+			tryToClose(c);
 			throw new DbException(e);
 		}
 	}
 
 	@Override
-	public long getFreeSpace() {
+	public long getFreeSpace() throws DbException {
 		File dir = config.getDatabaseDirectory();
 		long maxSize = config.getMaxSize();
 		long free = dir.getFreeSpace();
@@ -130,8 +121,8 @@ class HyperSqlDatabase extends JdbcDatabase {
 			s.close();
 			c.close();
 		} catch (SQLException e) {
-			tryToClose(s, LOG, WARNING);
+			tryToClose(s);
-			tryToClose(c, LOG, WARNING);
+			tryToClose(c);
 			throw new DbException(e);
 		}
 	}

bramble-core/src/main/java/org/briarproject/bramble/db/JdbcUtils.java

@@ -1,42 +0,0 @@
-package org.briarproject.bramble.db;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import java.sql.Connection;
-import java.sql.ResultSet;
-import java.sql.SQLException;
-import java.sql.Statement;
-import java.util.logging.Level;
-import java.util.logging.Logger;
-
-import javax.annotation.Nullable;
-
-import static org.briarproject.bramble.util.LogUtils.logException;
-
-@NotNullByDefault
-class JdbcUtils {
-
-	static void tryToClose(@Nullable ResultSet rs, Logger logger, Level level) {
-		try {
-			if (rs != null) rs.close();
-		} catch (SQLException e) {
-			logException(logger, level, e);
-		}
-	}
-
-	static void tryToClose(@Nullable Statement s, Logger logger, Level level) {
-		try {
-			if (s != null) s.close();
-		} catch (SQLException e) {
-			logException(logger, level, e);
-		}
-	}
-
-	static void tryToClose(@Nullable Connection c, Logger logger, Level level) {
-		try {
-			if (c != null) c.close();
-		} catch (SQLException e) {
-			logException(logger, level, e);
-		}
-	}
-}

bramble-core/src/main/java/org/briarproject/bramble/db/Migration38_39.java

@@ -7,8 +7,10 @@ import java.sql.SQLException;
 import java.sql.Statement;
 import java.util.logging.Logger;
 
+import javax.annotation.Nullable;
+
 import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.db.JdbcUtils.tryToClose;
+import static org.briarproject.bramble.util.LogUtils.logException;
 
 class Migration38_39 implements Migration<Connection> {
 
@@ -38,8 +40,16 @@ class Migration38_39 implements Migration<Connection> {
 					+ " ALTER COLUMN contactId"
 					+ " SET NOT NULL");
 		} catch (SQLException e) {
-			tryToClose(s, LOG, WARNING);
+			tryToClose(s);
 			throw new DbException(e);
 		}
 	}
+
+	private void tryToClose(@Nullable Statement s) {
+		try {
+			if (s != null) s.close();
+		} catch (SQLException e) {
+			logException(LOG, WARNING, e);
+		}
+	}
 }

bramble-core/src/main/java/org/briarproject/bramble/db/Migration39_40.java

@@ -7,8 +7,10 @@ import java.sql.SQLException;
 import java.sql.Statement;
 import java.util.logging.Logger;
 
+import javax.annotation.Nullable;
+
 import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.db.JdbcUtils.tryToClose;
+import static org.briarproject.bramble.util.LogUtils.logException;
 
 class Migration39_40 implements Migration<Connection> {
 
@@ -37,8 +39,16 @@ class Migration39_40 implements Migration<Connection> {
 					+ " ALTER COLUMN eta"
 					+ " SET NOT NULL");
 		} catch (SQLException e) {
-			tryToClose(s, LOG, WARNING);
+			tryToClose(s);
 			throw new DbException(e);
 		}
 	}
+
+	private void tryToClose(@Nullable Statement s) {
+		try {
+			if (s != null) s.close();
+		} catch (SQLException e) {
+			logException(LOG, WARNING, e);
+		}
+	}
 }

bramble-core/src/main/java/org/briarproject/bramble/db/Migration40_41.java

@@ -1,46 +0,0 @@
-package org.briarproject.bramble.db;
-
-import org.briarproject.bramble.api.db.DbException;
-
-import java.sql.Connection;
-import java.sql.SQLException;
-import java.sql.Statement;
-import java.util.logging.Logger;
-
-import static java.util.logging.Level.WARNING;
-import static java.util.logging.Logger.getLogger;
-import static org.briarproject.bramble.db.JdbcUtils.tryToClose;
-
-class Migration40_41 implements Migration<Connection> {
-
-	private static final Logger LOG = getLogger(Migration40_41.class.getName());
-
-	private final DatabaseTypes dbTypes;
-
-	public Migration40_41(DatabaseTypes databaseTypes) {
-		this.dbTypes = databaseTypes;
-	}
-
-	@Override
-	public int getStartVersion() {
-		return 40;
-	}
-
-	@Override
-	public int getEndVersion() {
-		return 41;
-	}
-
-	@Override
-	public void migrate(Connection txn) throws DbException {
-		Statement s = null;
-		try {
-			s = txn.createStatement();
-			s.execute("ALTER TABLE contacts"
-					+ dbTypes.replaceTypes(" ADD alias _STRING"));
-		} catch (SQLException e) {
-			tryToClose(s, LOG, WARNING);
-			throw new DbException(e);
-		}
-	}
-}

bramble-core/src/main/java/org/briarproject/bramble/identity/IdentityManagerImpl.java

@@ -1,21 +1,29 @@
 package org.briarproject.bramble.identity;
 
+import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.KeyPair;
 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.identity.Author.Status;
 import org.briarproject.bramble.api.identity.AuthorFactory;
+import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
+import java.util.Collection;
 import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
 import javax.annotation.concurrent.ThreadSafe;
 import javax.inject.Inject;
 
+import static org.briarproject.bramble.api.identity.Author.Status.OURSELVES;
+import static org.briarproject.bramble.api.identity.Author.Status.UNKNOWN;
+import static org.briarproject.bramble.api.identity.Author.Status.UNVERIFIED;
+import static org.briarproject.bramble.api.identity.Author.Status.VERIFIED;
 import static org.briarproject.bramble.util.LogUtils.logDuration;
 import static org.briarproject.bramble.util.LogUtils.now;
 
@@ -67,16 +75,27 @@ class IdentityManagerImpl implements IdentityManager {
 			LOG.info("No local author to store");
 			return;
 		}
-		db.transaction(false, txn -> db.addLocalAuthor(txn, cached));
+		Transaction txn = db.startTransaction(false);
-		LOG.info("Local author stored");
+		try {
+			db.addLocalAuthor(txn, cached);
+			db.commitTransaction(txn);
+			LOG.info("Local author stored");
+		} finally {
+			db.endTransaction(txn);
+		}
 	}
 
 	@Override
 	public LocalAuthor getLocalAuthor() throws DbException {
 		if (cachedAuthor == null) {
-			cachedAuthor =
+			Transaction txn = db.startTransaction(true);
-					db.transactionWithResult(true, this::loadLocalAuthor);
+			try {
-			LOG.info("Local author loaded");
+				cachedAuthor = loadLocalAuthor(txn);
+				LOG.info("Local author loaded");
+				db.commitTransaction(txn);
+			} finally {
+				db.endTransaction(txn);
+			}
 		}
 		LocalAuthor cached = cachedAuthor;
 		if (cached == null) throw new AssertionError();
@@ -99,4 +118,26 @@ class IdentityManagerImpl implements IdentityManager {
 		return db.getLocalAuthors(txn).iterator().next();
 	}
 
+	@Override
+	public Status getAuthorStatus(AuthorId authorId) throws DbException {
+		Transaction txn = db.startTransaction(true);
+		try {
+			return getAuthorStatus(txn, authorId);
+		} finally {
+			db.endTransaction(txn);
+		}
+	}
+
+	@Override
+	public Status getAuthorStatus(Transaction txn, AuthorId authorId)
+			throws DbException {
+		if (getLocalAuthor(txn).getId().equals(authorId)) return OURSELVES;
+		Collection<Contact> contacts = db.getContactsByAuthorId(txn, authorId);
+		if (contacts.isEmpty()) return UNKNOWN;
+		for (Contact c : contacts) {
+			if (c.isVerified()) return VERIFIED;
+		}
+		return UNVERIFIED;
+	}
+
 }

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

@@ -1,155 +0,0 @@
-package org.briarproject.bramble.io;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.InterruptedIOException;
-import java.util.concurrent.ArrayBlockingQueue;
-import java.util.concurrent.BlockingQueue;
-
-import javax.annotation.Nullable;
-import javax.annotation.concurrent.GuardedBy;
-import javax.annotation.concurrent.ThreadSafe;
-
-import static java.lang.System.arraycopy;
-import static java.lang.Thread.currentThread;
-
-/**
- * An {@link InputStream} that asynchronously fetches blocks of data on demand.
- */
-@ThreadSafe
-@NotNullByDefault
-abstract class BlockInputStream extends InputStream {
-
-	private final int minBufferBytes;
-	private final BlockingQueue<Buffer> queue = new ArrayBlockingQueue<>(1);
-	private final Object lock = new Object();
-
-	@GuardedBy("lock")
-	@Nullable
-	private Buffer buffer = null;
-
-	@GuardedBy("lock")
-	private int offset = 0;
-
-	@GuardedBy("lock")
-	private boolean fetchingBlock = false;
-
-	abstract void fetchBlockAsync(int blockNumber);
-
-	BlockInputStream(int minBufferBytes) {
-		this.minBufferBytes = minBufferBytes;
-	}
-
-	@Override
-	public int read() throws IOException {
-		synchronized (lock) {
-			if (!prepareRead()) return -1;
-			if (buffer == null) throw new AssertionError();
-			return buffer.data[offset++] & 0xFF;
-		}
-	}
-
-	@Override
-	public int read(byte[] b) throws IOException {
-		return read(b, 0, b.length);
-	}
-
-	@Override
-	public int read(byte[] b, int off, int len) throws IOException {
-		if (off < 0 || len < 0 || off + len > b.length)
-			throw new IllegalArgumentException();
-		synchronized (lock) {
-			if (!prepareRead()) return -1;
-			if (buffer == null) throw new AssertionError();
-			len = Math.min(len, buffer.length - offset);
-			if (len < 0) throw new AssertionError();
-			arraycopy(buffer.data, offset, b, off, len);
-			offset += len;
-			return len;
-		}
-	}
-
-	private boolean prepareRead() throws IOException {
-		throwExceptionIfNecessary();
-		if (isEndOfStream()) return false;
-		if (shouldFetchBlock()) fetchBlockAsync();
-		waitForBlock();
-		if (buffer == null) throw new AssertionError();
-		return offset < buffer.length;
-	}
-
-	@GuardedBy("lock")
-	private void throwExceptionIfNecessary() throws IOException {
-		if (buffer != null && buffer.exception != null)
-			throw new IOException(buffer.exception);
-	}
-
-	@GuardedBy("lock")
-	private boolean isEndOfStream() {
-		return buffer != null && offset == buffer.length && !fetchingBlock;
-	}
-
-	@GuardedBy("lock")
-	private boolean shouldFetchBlock() {
-		if (fetchingBlock) return false;
-		if (buffer == null) return true;
-		if (buffer.length == 0) return false;
-		return buffer.length - offset < minBufferBytes;
-	}
-
-	@GuardedBy("lock")
-	private void fetchBlockAsync() {
-		if (buffer == null) fetchBlockAsync(0);
-		else fetchBlockAsync(buffer.blockNumber + 1);
-		fetchingBlock = true;
-	}
-
-	@GuardedBy("lock")
-	private void waitForBlock() throws IOException {
-		if (buffer != null && offset < buffer.length) return;
-		try {
-			buffer = queue.take();
-		} catch (InterruptedException e) {
-			currentThread().interrupt();
-			throw new InterruptedIOException();
-		}
-		fetchingBlock = false;
-		offset = 0;
-		throwExceptionIfNecessary();
-	}
-
-	void fetchSucceeded(int blockNumber, byte[] data, int length) {
-		queue.add(new Buffer(blockNumber, data, length));
-	}
-
-	void fetchFailed(int blockNumber, Exception exception) {
-		queue.add(new Buffer(blockNumber, exception));
-	}
-
-	private static class Buffer {
-
-		private final int blockNumber;
-		private final byte[] data;
-		private final int length;
-		@Nullable
-		private final Exception exception;
-
-		private Buffer(int blockNumber, byte[] data, int length) {
-			if (length < 0 || length > data.length)
-				throw new IllegalArgumentException();
-			this.blockNumber = blockNumber;
-			this.data = data;
-			this.length = length;
-			exception = null;
-		}
-
-		private Buffer(int blockNumber, Exception exception) {
-			this.blockNumber = blockNumber;
-			this.exception = exception;
-			data = new byte[0];
-			length = 0;
-		}
-	}
-}

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

@@ -1,53 +0,0 @@
-package org.briarproject.bramble.io;
-
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.io.BlockSource;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.sync.MessageId;
-
-import java.util.concurrent.Executor;
-
-import javax.annotation.concurrent.ThreadSafe;
-
-/**
- * A {@link BlockInputStream} that fetches data from a {@link BlockSource}.
- */
-@ThreadSafe
-@NotNullByDefault
-class BlockSourceInputStream extends BlockInputStream {
-
-	private final Executor executor;
-	private final BlockSource blockSource;
-	private final MessageId messageId;
-
-	private volatile int blockCount = -1;
-
-	BlockSourceInputStream(int minBufferBytes, Executor executor,
-			BlockSource blockSource, MessageId messageId) {
-		super(minBufferBytes);
-		this.executor = executor;
-		this.blockSource = blockSource;
-		this.messageId = messageId;
-	}
-
-	@Override
-	void fetchBlockAsync(int blockNumber) {
-		executor.execute(() -> {
-			try {
-				if (blockCount == -1) {
-					blockCount = blockSource.getBlockCount(messageId);
-				}
-				if (blockNumber > blockCount) {
-					fetchFailed(blockNumber, new IllegalArgumentException());
-				} else if (blockNumber == blockCount) {
-					fetchSucceeded(blockNumber, new byte[0], 0); // EOF
-				} else {
-					byte[] block = blockSource.getBlock(messageId, blockNumber);
-					fetchSucceeded(blockNumber, block, block.length);
-				}
-			} catch (DbException e) {
-				fetchFailed(blockNumber, e);
-			}
-		});
-	}
-}

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

@@ -1,16 +0,0 @@
-package org.briarproject.bramble.io;
-
-import org.briarproject.bramble.api.io.MessageInputStreamFactory;
-
-import dagger.Module;
-import dagger.Provides;
-
-@Module
-public class IoModule {
-
-	@Provides
-	MessageInputStreamFactory provideMessageInputStreamFactory(
-			MessageInputStreamFactoryImpl messageInputStreamFactory) {
-		return messageInputStreamFactory;
-	}
-}

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

@@ -1,32 +0,0 @@
-package org.briarproject.bramble.io;
-
-import org.briarproject.bramble.api.db.DatabaseExecutor;
-import org.briarproject.bramble.api.io.BlockSource;
-import org.briarproject.bramble.api.io.MessageInputStreamFactory;
-import org.briarproject.bramble.api.sync.MessageId;
-
-import java.io.InputStream;
-import java.util.concurrent.Executor;
-
-import javax.inject.Inject;
-
-import static org.briarproject.bramble.api.sync.SyncConstants.MAX_BLOCK_LENGTH;
-
-class MessageInputStreamFactoryImpl implements MessageInputStreamFactory {
-
-	private final Executor dbExecutor;
-	private final BlockSource blockSource;
-
-	@Inject
-	MessageInputStreamFactoryImpl(@DatabaseExecutor Executor dbExecutor,
-			BlockSource blockSource) {
-		this.dbExecutor = dbExecutor;
-		this.blockSource = blockSource;
-	}
-
-	@Override
-	public InputStream getMessageInputStream(MessageId m) {
-		return new BlockSourceInputStream(MAX_BLOCK_LENGTH, dbExecutor,
-				blockSource, m);
-	}
-}

bramble-core/src/main/java/org/briarproject/bramble/lifecycle/LifecycleManagerImpl.java

@@ -6,6 +6,7 @@ import org.briarproject.bramble.api.db.DataTooOldException;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.MigrationListener;
+import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.identity.IdentityManager;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
@@ -114,16 +115,20 @@ class LifecycleManagerImpl implements LifecycleManager, MigrationListener {
 			dbLatch.countDown();
 			eventBus.broadcast(new LifecycleEvent(STARTING_SERVICES));
 
-			db.transaction(false, txn -> {
+			Transaction txn = db.startTransaction(false);
+			try {
 				for (Client c : clients) {
-					long start1 = now();
+					start = now();
 					c.createLocalState(txn);
 					if (LOG.isLoggable(FINE)) {
 						logDuration(LOG, "Starting client "
-								+ c.getClass().getSimpleName(), start1);
+								+ c.getClass().getSimpleName(), start);
 					}
 				}
-			});
+				db.commitTransaction(txn);
+			} finally {
+				db.endTransaction(txn);
+			}
 			for (Service s : services) {
 				start = now();
 				s.startService();

bramble-core/src/main/java/org/briarproject/bramble/plugin/bluetooth/BluetoothPlugin.java

@@ -23,6 +23,7 @@ import org.briarproject.bramble.api.plugin.event.EnableBluetoothEvent;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.settings.Settings;
 import org.briarproject.bramble.api.settings.event.SettingsUpdatedEvent;
+import org.briarproject.bramble.util.StringUtils;
 
 import java.io.IOException;
 import java.security.SecureRandom;
@@ -45,9 +46,6 @@ import static org.briarproject.bramble.api.plugin.BluetoothConstants.PROP_UUID;
 import static org.briarproject.bramble.api.plugin.BluetoothConstants.UUID_BYTES;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.PrivacyUtils.scrubMacAddress;
-import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
-import static org.briarproject.bramble.util.StringUtils.macToBytes;
-import static org.briarproject.bramble.util.StringUtils.macToString;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
@@ -98,9 +96,6 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	abstract DuplexTransportConnection connectTo(String address, String uuid)
 			throws IOException;
 
-	@Nullable
-	abstract DuplexTransportConnection discoverAndConnect(String uuid);
-
 	BluetoothPlugin(BluetoothConnectionLimiter connectionLimiter,
 			Executor ioExecutor, SecureRandom secureRandom,
 			Backoff backoff, DuplexPluginCallback callback, int maxLatency) {
@@ -198,7 +193,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 			address = getBluetoothAddress();
 			if (LOG.isLoggable(INFO))
 				LOG.info("Local address " + scrubMacAddress(address));
-			if (!isNullOrEmpty(address)) {
+			if (!StringUtils.isNullOrEmpty(address)) {
 				p.put(PROP_ADDRESS, address);
 				changed = true;
 			}
@@ -261,9 +256,9 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		// Try to connect to known devices in parallel
 		for (Entry<ContactId, TransportProperties> e : contacts.entrySet()) {
 			String address = e.getValue().get(PROP_ADDRESS);
-			if (isNullOrEmpty(address)) continue;
+			if (StringUtils.isNullOrEmpty(address)) continue;
 			String uuid = e.getValue().get(PROP_UUID);
-			if (isNullOrEmpty(uuid)) continue;
+			if (StringUtils.isNullOrEmpty(uuid)) continue;
 			ContactId c = e.getKey();
 			ioExecutor.execute(() -> {
 				if (!isRunning() || !shouldAllowContactConnections()) return;
@@ -314,9 +309,9 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		if (!isRunning() || !shouldAllowContactConnections()) return null;
 		if (!connectionLimiter.canOpenContactConnection()) return null;
 		String address = p.get(PROP_ADDRESS);
-		if (isNullOrEmpty(address)) return null;
+		if (StringUtils.isNullOrEmpty(address)) return null;
 		String uuid = p.get(PROP_UUID);
-		if (isNullOrEmpty(uuid)) return null;
+		if (StringUtils.isNullOrEmpty(uuid)) return null;
 		DuplexTransportConnection conn = connect(address, uuid);
 		if (conn == null) return null;
 		// TODO: Why don't we reset the backoff here?
@@ -331,6 +326,9 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	@Override
 	public KeyAgreementListener createKeyAgreementListener(byte[] commitment) {
 		if (!isRunning()) return null;
+		// There's no point listening if we can't discover our own address
+		String address = getBluetoothAddress();
+		if (address == null) return null;
 		// No truncation necessary because COMMIT_LENGTH = 16
 		String uuid = UUID.nameUUIDFromBytes(commitment).toString();
 		if (LOG.isLoggable(INFO)) LOG.info("Key agreement UUID " + uuid);
@@ -348,8 +346,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 		}
 		BdfList descriptor = new BdfList();
 		descriptor.add(TRANSPORT_ID_BLUETOOTH);
-		String address = getBluetoothAddress();
+		descriptor.add(StringUtils.macToBytes(address));
-		if (address != null) descriptor.add(macToBytes(address));
 		return new BluetoothKeyAgreementListener(descriptor, ss);
 	}
 
@@ -357,25 +354,18 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	public DuplexTransportConnection createKeyAgreementConnection(
 			byte[] commitment, BdfList descriptor) {
 		if (!isRunning()) return null;
+		String address;
+		try {
+			address = parseAddress(descriptor);
+		} catch (FormatException e) {
+			LOG.info("Invalid address in key agreement descriptor");
+			return null;
+		}
 		// No truncation necessary because COMMIT_LENGTH = 16
 		String uuid = UUID.nameUUIDFromBytes(commitment).toString();
-		DuplexTransportConnection conn;
+		if (LOG.isLoggable(INFO))
-		if (descriptor.size() == 1) {
+			LOG.info("Connecting to key agreement UUID " + uuid);
-			if (LOG.isLoggable(INFO))
+		DuplexTransportConnection conn = connect(address, uuid);
-				LOG.info("Discovering address for key agreement UUID " + uuid);
-			conn = discoverAndConnect(uuid);
-		} else {
-			String address;
-			try {
-				address = parseAddress(descriptor);
-			} catch (FormatException e) {
-				LOG.info("Invalid address in key agreement descriptor");
-				return null;
-			}
-			if (LOG.isLoggable(INFO))
-				LOG.info("Connecting to key agreement UUID " + uuid);
-			conn = connect(address, uuid);
-		}
 		if (conn != null) connectionLimiter.keyAgreementConnectionOpened(conn);
 		return conn;
 	}
@@ -383,7 +373,7 @@ abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
 	private String parseAddress(BdfList descriptor) throws FormatException {
 		byte[] mac = descriptor.getRaw(1);
 		if (mac.length != 6) throw new FormatException();
-		return macToString(mac);
+		return StringUtils.macToString(mac);
 	}
 
 	@Override

bramble-core/src/main/java/org/briarproject/bramble/plugin/file/FileTransportReader.java

@@ -4,11 +4,12 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportConnectionReader;
 
 import java.io.File;
+import java.io.IOException;
 import java.io.InputStream;
 import java.util.logging.Logger;
 
 import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.util.IoUtils.tryToClose;
+import static org.briarproject.bramble.util.LogUtils.logException;
 
 @NotNullByDefault
 class FileTransportReader implements TransportConnectionReader {
@@ -33,7 +34,11 @@ class FileTransportReader implements TransportConnectionReader {
 
 	@Override
 	public void dispose(boolean exception, boolean recognised) {
-		tryToClose(in, LOG, WARNING);
+		try {
+			in.close();
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+		}
 		plugin.readerFinished(file, exception, recognised);
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/plugin/file/FileTransportWriter.java

@@ -4,11 +4,12 @@ import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
 
 import java.io.File;
+import java.io.IOException;
 import java.io.OutputStream;
 import java.util.logging.Logger;
 
 import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.util.IoUtils.tryToClose;
+import static org.briarproject.bramble.util.LogUtils.logException;
 
 @NotNullByDefault
 class FileTransportWriter implements TransportConnectionWriter {
@@ -43,7 +44,11 @@ class FileTransportWriter implements TransportConnectionWriter {
 
 	@Override
 	public void dispose(boolean exception) {
-		tryToClose(out, LOG, WARNING);
+		try {
+			out.close();
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+		}
 		plugin.writerFinished(file, exception);
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/plugin/tcp/LanTcpPlugin.java

@@ -11,7 +11,6 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.properties.TransportProperties;
 import org.briarproject.bramble.api.settings.Settings;
-import org.briarproject.bramble.util.IoUtils;
 import org.briarproject.bramble.util.StringUtils;
 
 import java.io.IOException;
@@ -36,6 +35,7 @@ import static org.briarproject.bramble.api.plugin.LanTcpConstants.ID;
 import static org.briarproject.bramble.api.plugin.LanTcpConstants.PREF_LAN_IP_PORTS;
 import static org.briarproject.bramble.api.plugin.LanTcpConstants.PROP_IP_PORTS;
 import static org.briarproject.bramble.util.ByteUtils.MAX_16_BIT_UNSIGNED;
+import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.PrivacyUtils.scrubSocketAddress;
 
 @NotNullByDefault
@@ -293,7 +293,11 @@ class LanTcpPlugin extends TcpPlugin {
 
 		@Override
 		public void close() {
-			IoUtils.tryToClose(ss, LOG, WARNING);
+			try {
+				ss.close();
+			} catch (IOException e) {
+				logException(LOG, WARNING, e);
+			}
 		}
 	}
 

bramble-core/src/main/java/org/briarproject/bramble/plugin/tcp/TcpPlugin.java

@@ -11,7 +11,6 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginCallback;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.properties.TransportProperties;
-import org.briarproject.bramble.util.IoUtils;
 import org.briarproject.bramble.util.StringUtils;
 
 import java.io.IOException;
@@ -154,8 +153,13 @@ abstract class TcpPlugin implements DuplexPlugin {
 	}
 
 	protected void tryToClose(@Nullable ServerSocket ss) {
-		IoUtils.tryToClose(ss, LOG, WARNING);
+		try {
-		callback.transportDisabled();
+			if (ss != null) ss.close();
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+		} finally {
+			callback.transportDisabled();
+		}
 	}
 
 	String getIpPortString(InetSocketAddress a) {

bramble-core/src/main/java/org/briarproject/bramble/plugin/tor/TorPlugin.java

@@ -4,8 +4,6 @@ import net.freehaven.tor.control.EventHandler;
 import net.freehaven.tor.control.TorControlConnection;
 
 import org.briarproject.bramble.PoliteExecutor;
-import org.briarproject.bramble.api.battery.BatteryManager;
-import org.briarproject.bramble.api.battery.event.BatteryEvent;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.event.Event;
@@ -31,6 +29,7 @@ import org.briarproject.bramble.api.system.LocationUtils;
 import org.briarproject.bramble.api.system.ResourceProvider;
 import org.briarproject.bramble.util.IoUtils;
 
+import java.io.Closeable;
 import java.io.EOFException;
 import java.io.File;
 import java.io.FileInputStream;
@@ -97,14 +96,13 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private final LocationUtils locationUtils;
 	private final SocketFactory torSocketFactory;
 	private final Clock clock;
-	private final BatteryManager batteryManager;
 	private final Backoff backoff;
 	private final DuplexPluginCallback callback;
 	private final String architecture;
 	private final CircumventionProvider circumventionProvider;
 	private final ResourceProvider resourceProvider;
 	private final int maxLatency, maxIdleTime, socketTimeout;
-	private final File torDirectory, torFile, geoIpFile, obfs4File, configFile;
+	private final File torDirectory, torFile, geoIpFile, configFile;
 	private final File doneFile, cookieFile;
 	private final ConnectionStatus connectionStatus;
 	private final AtomicBoolean used = new AtomicBoolean(false);
@@ -123,8 +121,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	TorPlugin(Executor ioExecutor, NetworkManager networkManager,
 			LocationUtils locationUtils, SocketFactory torSocketFactory,
 			Clock clock, ResourceProvider resourceProvider,
-			CircumventionProvider circumventionProvider,
+			CircumventionProvider circumventionProvider, Backoff backoff,
-			BatteryManager batteryManager, Backoff backoff,
 			DuplexPluginCallback callback, String architecture, int maxLatency,
 			int maxIdleTime, File torDirectory) {
 		this.ioExecutor = ioExecutor;
@@ -134,7 +131,6 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		this.clock = clock;
 		this.resourceProvider = resourceProvider;
 		this.circumventionProvider = circumventionProvider;
-		this.batteryManager = batteryManager;
 		this.backoff = backoff;
 		this.callback = callback;
 		this.architecture = architecture;
@@ -146,7 +142,6 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		this.torDirectory = torDirectory;
 		torFile = new File(torDirectory, "tor");
 		geoIpFile = new File(torDirectory, "geoip");
-		obfs4File = new File(torDirectory, "obfs4proxy");
 		configFile = new File(torDirectory, "torrc");
 		doneFile = new File(torDirectory, "done");
 		cookieFile = new File(torDirectory, ".tor/control_auth_cookie");
@@ -265,8 +260,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			throw new PluginException(e);
 		}
 		// Check whether we're online
-		updateConnectionStatus(networkManager.getNetworkStatus(),
+		updateConnectionStatus(networkManager.getNetworkStatus());
-				batteryManager.isCharging());
 		// Bind a server socket to receive incoming hidden service connections
 		bind();
 	}
@@ -290,20 +284,14 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			in = getGeoIpInputStream();
 			out = new FileOutputStream(geoIpFile);
 			IoUtils.copyAndClose(in, out);
-			// Unzip the Obfs4 proxy to the filesystem
-			in = getObfs4InputStream();
-			out = new FileOutputStream(obfs4File);
-			IoUtils.copyAndClose(in, out);
-			// Make the Obfs4 proxy executable
-			if (!obfs4File.setExecutable(true, true)) throw new IOException();
 			// Copy the config file to the filesystem
 			in = getConfigInputStream();
 			out = new FileOutputStream(configFile);
 			IoUtils.copyAndClose(in, out);
 			doneFile.createNewFile();
 		} catch (IOException e) {
-			IoUtils.tryToClose(in, LOG, WARNING);
+			tryToClose(in);
-			IoUtils.tryToClose(out, LOG, WARNING);
+			tryToClose(out);
 			throw new PluginException(e);
 		}
 	}
@@ -326,20 +314,26 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		return zin;
 	}
 
-	private InputStream getObfs4InputStream() throws IOException {
-		if (LOG.isLoggable(INFO))
-			LOG.info("Installing obfs4proxy binary for " + architecture);
-		InputStream in = resourceProvider
-				.getResourceInputStream("obfs4proxy_" + architecture, ".zip");
-		ZipInputStream zin = new ZipInputStream(in);
-		if (zin.getNextEntry() == null) throw new IOException();
-		return zin;
-	}
-
 	private InputStream getConfigInputStream() {
 		return getClass().getClassLoader().getResourceAsStream("torrc");
 	}
 
+	private void tryToClose(@Nullable Closeable c) {
+		try {
+			if (c != null) c.close();
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+		}
+	}
+
+	private void tryToClose(@Nullable Socket s) {
+		try {
+			if (s != null) s.close();
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+		}
+	}
+
 	private void listFiles(File f) {
 		if (f.isDirectory()) {
 			File[] children = f.listFiles();
@@ -361,7 +355,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			}
 			return b;
 		} finally {
-			IoUtils.tryToClose(in, LOG, WARNING);
+			tryToClose(in);
 		}
 	}
 
@@ -401,8 +395,13 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	private void tryToClose(@Nullable ServerSocket ss) {
-		IoUtils.tryToClose(ss, LOG, WARNING);
+		try {
-		callback.transportDisabled();
+			if (ss != null) ss.close();
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+		} finally {
+			callback.transportDisabled();
+		}
 	}
 
 	private void publishHiddenService(String port) {
@@ -473,8 +472,6 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		if (enable) {
 			Collection<String> conf = new ArrayList<>();
 			conf.add("UseBridges 1");
-			conf.add("ClientTransportPlugin obfs4 exec " +
-					obfs4File.getAbsolutePath());
 			conf.addAll(circumventionProvider.getBridges());
 			controlConnection.setConf(conf);
 		} else {
@@ -571,7 +568,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 				LOG.info("Could not connect to " + scrubOnion(bestOnion)
 						+ ": " + e.toString());
 			}
-			IoUtils.tryToClose(s, LOG, WARNING);
+			tryToClose(s);
 			return null;
 		}
 	}
@@ -612,8 +609,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			LOG.info("OR connection " + status + " " + orName);
 		if (status.equals("CLOSED") || status.equals("FAILED")) {
 			// Check whether we've lost connectivity
-			updateConnectionStatus(networkManager.getNetworkStatus(),
+			updateConnectionStatus(networkManager.getNetworkStatus());
-					batteryManager.isCharging());
 		}
 	}
 
@@ -651,15 +647,10 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 				// Works around a bug introduced in Tor 0.3.4.8. Could be
 				// replaced with callback.transportDisabled() when fixed.
 				disableNetwork();
-				updateConnectionStatus(networkManager.getNetworkStatus(),
+				updateConnectionStatus(networkManager.getNetworkStatus());
-						batteryManager.isCharging());
 			}
 		} else if (e instanceof NetworkStatusEvent) {
-			updateConnectionStatus(((NetworkStatusEvent) e).getStatus(),
+			updateConnectionStatus(((NetworkStatusEvent) e).getStatus());
-					batteryManager.isCharging());
-		} else if (e instanceof BatteryEvent) {
-			updateConnectionStatus(networkManager.getNetworkStatus(),
-					((BatteryEvent) e).isCharging());
 		}
 	}
 
@@ -673,8 +664,7 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		});
 	}
 
-	private void updateConnectionStatus(NetworkStatus status,
+	private void updateConnectionStatus(NetworkStatus status) {
-			boolean charging) {
 		connectionStatusExecutor.execute(() -> {
 			if (!running) return;
 			boolean online = status.isConnected();
@@ -692,7 +682,6 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 				LOG.info("Online: " + online + ", wifi: " + wifi);
 				if ("".equals(country)) LOG.info("Country code unknown");
 				else LOG.info("Country code: " + country);
-				LOG.info("Charging: " + charging);
 			}
 
 			try {
@@ -716,24 +705,12 @@ abstract class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 					enableBridges(false);
 					enableNetwork(true);
 				}
-				if (online && wifi && charging) {
-					LOG.info("Enabling connection padding");
-					enableConnectionPadding(true);
-				} else {
-					LOG.info("Disabling connection padding");
-					enableConnectionPadding(false);
-				}
 			} catch (IOException e) {
 				logException(LOG, WARNING, e);
 			}
 		});
 	}
 
-	private void enableConnectionPadding(boolean enable) throws IOException {
-		if (!running) return;
-		controlConnection.setConf("ConnectionPadding", enable ? "1" : "0");
-	}
-
 	// TODO remove when sufficient time has passed. Added 2018-08-15
 	private void migrateSettings() {
 		Settings sOld = callback.getSettings();

bramble-core/src/main/java/org/briarproject/bramble/properties/PropertiesModule.java

@@ -5,7 +5,7 @@ import org.briarproject.bramble.api.contact.ContactManager;
 import org.briarproject.bramble.api.data.MetadataEncoder;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.properties.TransportPropertyManager;
-import org.briarproject.bramble.api.sync.validation.ValidationManager;
+import org.briarproject.bramble.api.sync.ValidationManager;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.versioning.ClientVersioningManager;
 

bramble-core/src/main/java/org/briarproject/bramble/properties/TransportPropertyManagerImpl.java

@@ -24,7 +24,7 @@ import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.InvalidMessageException;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageId;
-import org.briarproject.bramble.api.sync.validation.IncomingMessageHook;
+import org.briarproject.bramble.api.sync.ValidationManager.IncomingMessageHook;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.versioning.ClientVersioningManager;
 import org.briarproject.bramble.api.versioning.ClientVersioningManager.ClientVersioningHook;
@@ -142,7 +142,15 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	@Override
 	public Map<TransportId, TransportProperties> getLocalProperties()
 			throws DbException {
-		return db.transactionWithResult(true, this::getLocalProperties);
+		Map<TransportId, TransportProperties> local;
+		Transaction txn = db.startTransaction(true);
+		try {
+			local = getLocalProperties(txn);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
+		return local;
 	}
 
 	@Override
@@ -168,8 +176,9 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	public TransportProperties getLocalProperties(TransportId t)
 			throws DbException {
 		try {
-			return db.transactionWithResult(true, txn -> {
+			TransportProperties p = null;
-				TransportProperties p = null;
+			Transaction txn = db.startTransaction(true);
+			try {
 				// Find the latest local update
 				LatestUpdate latest = findLatest(txn, localGroup.getId(), t,
 						true);
@@ -179,8 +188,11 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 							latest.messageId);
 					p = parseProperties(message);
 				}
-				return p == null ? new TransportProperties() : p;
+				db.commitTransaction(txn);
-			});
+			} finally {
+				db.endTransaction(txn);
+			}
+			return p == null ? new TransportProperties() : p;
 		} catch (FormatException e) {
 			throw new DbException(e);
 		}
@@ -189,12 +201,16 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	@Override
 	public Map<ContactId, TransportProperties> getRemoteProperties(
 			TransportId t) throws DbException {
-		return db.transactionWithResult(true, txn -> {
+		Map<ContactId, TransportProperties> remote = new HashMap<>();
-			Map<ContactId, TransportProperties> remote = new HashMap<>();
+		Transaction txn = db.startTransaction(true);
+		try {
 			for (Contact c : db.getContacts(txn))
 				remote.put(c.getId(), getRemoteProperties(txn, c, t));
-			return remote;
+			db.commitTransaction(txn);
-		});
+		} finally {
+			db.endTransaction(txn);
+		}
+		return remote;
 	}
 
 	private TransportProperties getRemoteProperties(Transaction txn, Contact c,
@@ -218,15 +234,23 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 	@Override
 	public TransportProperties getRemoteProperties(ContactId c, TransportId t)
 			throws DbException {
-		return db.transactionWithResult(true, txn ->
+		TransportProperties p;
-				getRemoteProperties(txn, db.getContact(txn, c), t));
+		Transaction txn = db.startTransaction(true);
+		try {
+			p = getRemoteProperties(txn, db.getContact(txn, c), t);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
+		return p;
 	}
 
 	@Override
 	public void mergeLocalProperties(TransportId t, TransportProperties p)
 			throws DbException {
 		try {
-			db.transaction(false, txn -> {
+			Transaction txn = db.startTransaction(false);
+			try {
 				// Merge the new properties with any existing properties
 				TransportProperties merged;
 				boolean changed;
@@ -263,7 +287,10 @@ class TransportPropertyManagerImpl implements TransportPropertyManager,
 							db.removeMessage(txn, latest.messageId);
 					}
 				}
-			});
+				db.commitTransaction(txn);
+			} finally {
+				db.endTransaction(txn);
+			}
 		} catch (FormatException e) {
 			throw new DbException(e);
 		}

bramble-core/src/main/java/org/briarproject/bramble/reporting/DevReporterImpl.java

@@ -12,6 +12,7 @@ import org.briarproject.bramble.api.reporting.DevReporter;
 import org.briarproject.bramble.util.IoUtils;
 import org.briarproject.bramble.util.StringUtils;
 
+import java.io.Closeable;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileNotFoundException;
@@ -25,12 +26,13 @@ import java.net.Socket;
 import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
+import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 import javax.net.SocketFactory;
 
 import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.util.IoUtils.tryToClose;
+import static org.briarproject.bramble.util.LogUtils.logException;
 
 @Immutable
 @NotNullByDefault
@@ -64,7 +66,7 @@ class DevReporterImpl implements DevReporter, EventListener {
 			s.setSoTimeout(SOCKET_TIMEOUT);
 			return s;
 		} catch (IOException e) {
-			tryToClose(s, LOG, WARNING);
+			tryToClose(s);
 			throw e;
 		}
 	}
@@ -86,7 +88,8 @@ class DevReporterImpl implements DevReporter, EventListener {
 			writer.append(armoured);
 			writer.flush();
 		} finally {
-			tryToClose(writer, LOG, WARNING);
+			if (writer != null)
+				writer.close();
 		}
 	}
 
@@ -118,11 +121,27 @@ class DevReporterImpl implements DevReporter, EventListener {
 				f.delete();
 			} catch (IOException e) {
 				LOG.log(WARNING, "Failed to send reports", e);
-				tryToClose(out, LOG, WARNING);
+				tryToClose(out);
-				tryToClose(in, LOG, WARNING);
+				tryToClose(in);
 				return;
 			}
 		}
 		LOG.info("Reports sent");
 	}
+
+	private void tryToClose(@Nullable Closeable c) {
+		try {
+			if (c != null) c.close();
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+		}
+	}
+
+	private void tryToClose(@Nullable Socket s) {
+		try {
+			if (s != null) s.close();
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+		}
+	}
 }

bramble-core/src/main/java/org/briarproject/bramble/settings/SettingsManagerImpl.java

@@ -23,8 +23,15 @@ class SettingsManagerImpl implements SettingsManager {
 
 	@Override
 	public Settings getSettings(String namespace) throws DbException {
-		return db.transactionWithResult(true, txn ->
+		Settings s;
-				db.getSettings(txn, namespace));
+		Transaction txn = db.startTransaction(true);
+		try {
+			s = db.getSettings(txn, namespace);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
+		return s;
 	}
 
 	@Override
@@ -35,6 +42,12 @@ class SettingsManagerImpl implements SettingsManager {
 
 	@Override
 	public void mergeSettings(Settings s, String namespace) throws DbException {
-		db.transaction(false, txn -> db.mergeSettings(txn, s, namespace));
+		Transaction txn = db.startTransaction(false);
+		try {
+			db.mergeSettings(txn, s, namespace);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/sync/DuplexOutgoingSession.java

@@ -5,6 +5,7 @@ import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.event.EventListener;
@@ -229,8 +230,14 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 			if (interrupted) return;
 			if (!generateAckQueued.getAndSet(false)) throw new AssertionError();
 			try {
-				Ack a = db.transactionWithNullableResult(false, txn ->
+				Ack a;
-						db.generateAck(txn, contactId, MAX_MESSAGE_IDS));
+				Transaction txn = db.startTransaction(false);
+				try {
+					a = db.generateAck(txn, contactId, MAX_MESSAGE_IDS);
+					db.commitTransaction(txn);
+				} finally {
+					db.endTransaction(txn);
+				}
 				if (LOG.isLoggable(INFO))
 					LOG.info("Generated ack: " + (a != null));
 				if (a != null) writerTasks.add(new WriteAck(a));
@@ -268,15 +275,16 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 			if (!generateBatchQueued.getAndSet(false))
 				throw new AssertionError();
 			try {
-				Collection<Message> b =
+				Collection<Message> b;
-						db.transactionWithNullableResult(false, txn -> {
+				Transaction txn = db.startTransaction(false);
-							Collection<Message> batch =
+				try {
-									db.generateRequestedBatch(txn, contactId,
+					b = db.generateRequestedBatch(txn, contactId,
-											MAX_RECORD_PAYLOAD_BYTES,
+							MAX_RECORD_PAYLOAD_BYTES, maxLatency);
-											maxLatency);
+					setNextSendTime(db.getNextSendTime(txn, contactId));
-							setNextSendTime(db.getNextSendTime(txn, contactId));
+					db.commitTransaction(txn);
-							return batch;
+				} finally {
-						});
+					db.endTransaction(txn);
+				}
 				if (LOG.isLoggable(INFO))
 					LOG.info("Generated batch: " + (b != null));
 				if (b != null) writerTasks.add(new WriteBatch(b));
@@ -314,12 +322,16 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 			if (!generateOfferQueued.getAndSet(false))
 				throw new AssertionError();
 			try {
-				Offer o = db.transactionWithNullableResult(false, txn -> {
+				Offer o;
-					Offer offer = db.generateOffer(txn, contactId,
+				Transaction txn = db.startTransaction(false);
-							MAX_MESSAGE_IDS, maxLatency);
+				try {
+					o = db.generateOffer(txn, contactId, MAX_MESSAGE_IDS,
+							maxLatency);
 					setNextSendTime(db.getNextSendTime(txn, contactId));
-					return offer;
+					db.commitTransaction(txn);
-				});
+				} finally {
+					db.endTransaction(txn);
+				}
 				if (LOG.isLoggable(INFO))
 					LOG.info("Generated offer: " + (o != null));
 				if (o != null) writerTasks.add(new WriteOffer(o));
@@ -357,8 +369,14 @@ class DuplexOutgoingSession implements SyncSession, EventListener {
 			if (!generateRequestQueued.getAndSet(false))
 				throw new AssertionError();
 			try {
-				Request r = db.transactionWithNullableResult(false, txn ->
+				Request r;
-						db.generateRequest(txn, contactId, MAX_MESSAGE_IDS));
+				Transaction txn = db.startTransaction(false);
+				try {
+					r = db.generateRequest(txn, contactId, MAX_MESSAGE_IDS);
+					db.commitTransaction(txn);
+				} finally {
+					db.endTransaction(txn);
+				}
 				if (LOG.isLoggable(INFO))
 					LOG.info("Generated request: " + (r != null));
 				if (r != null) writerTasks.add(new WriteRequest(r));

bramble-core/src/main/java/org/briarproject/bramble/sync/IncomingSession.java

@@ -6,6 +6,7 @@ import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.event.EventListener;
@@ -119,8 +120,13 @@ class IncomingSession implements SyncSession, EventListener {
 		@Override
 		public void run() {
 			try {
-				db.transaction(false, txn ->
+				Transaction txn = db.startTransaction(false);
-						db.receiveAck(txn, contactId, ack));
+				try {
+					db.receiveAck(txn, contactId, ack);
+					db.commitTransaction(txn);
+				} finally {
+					db.endTransaction(txn);
+				}
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 				interrupt();
@@ -140,8 +146,13 @@ class IncomingSession implements SyncSession, EventListener {
 		@Override
 		public void run() {
 			try {
-				db.transaction(false, txn ->
+				Transaction txn = db.startTransaction(false);
-						db.receiveMessage(txn, contactId, message));
+				try {
+					db.receiveMessage(txn, contactId, message);
+					db.commitTransaction(txn);
+				} finally {
+					db.endTransaction(txn);
+				}
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 				interrupt();
@@ -161,8 +172,13 @@ class IncomingSession implements SyncSession, EventListener {
 		@Override
 		public void run() {
 			try {
-				db.transaction(false, txn ->
+				Transaction txn = db.startTransaction(false);
-						db.receiveOffer(txn, contactId, offer));
+				try {
+					db.receiveOffer(txn, contactId, offer);
+					db.commitTransaction(txn);
+				} finally {
+					db.endTransaction(txn);
+				}
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 				interrupt();
@@ -182,8 +198,13 @@ class IncomingSession implements SyncSession, EventListener {
 		@Override
 		public void run() {
 			try {
-				db.transaction(false, txn ->
+				Transaction txn = db.startTransaction(false);
-						db.receiveRequest(txn, contactId, request));
+				try {
+					db.receiveRequest(txn, contactId, request);
+					db.commitTransaction(txn);
+				} finally {
+					db.endTransaction(txn);
+				}
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 				interrupt();

bramble-core/src/main/java/org/briarproject/bramble/sync/SimplexOutgoingSession.java

@@ -5,6 +5,7 @@ import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.event.EventListener;
@@ -46,8 +47,7 @@ class SimplexOutgoingSession implements SyncSession, EventListener {
 	private static final Logger LOG =
 			Logger.getLogger(SimplexOutgoingSession.class.getName());
 
-	private static final ThrowingRunnable<IOException> CLOSE = () -> {
+	private static final ThrowingRunnable<IOException> CLOSE = () -> {};
-	};
 
 	private final DatabaseComponent db;
 	private final Executor dbExecutor;
@@ -128,8 +128,14 @@ class SimplexOutgoingSession implements SyncSession, EventListener {
 		public void run() {
 			if (interrupted) return;
 			try {
-				Ack a = db.transactionWithNullableResult(false, txn ->
+				Ack a;
-						db.generateAck(txn, contactId, MAX_MESSAGE_IDS));
+				Transaction txn = db.startTransaction(false);
+				try {
+					a = db.generateAck(txn, contactId, MAX_MESSAGE_IDS);
+					db.commitTransaction(txn);
+				} finally {
+					db.endTransaction(txn);
+				}
 				if (LOG.isLoggable(INFO))
 					LOG.info("Generated ack: " + (a != null));
 				if (a == null) decrementOutstandingQueries();
@@ -166,10 +172,15 @@ class SimplexOutgoingSession implements SyncSession, EventListener {
 		public void run() {
 			if (interrupted) return;
 			try {
-				Collection<Message> b =
+				Collection<Message> b;
-						db.transactionWithNullableResult(false, txn ->
+				Transaction txn = db.startTransaction(false);
-								db.generateBatch(txn, contactId,
+				try {
-										MAX_RECORD_PAYLOAD_BYTES, maxLatency));
+					b = db.generateBatch(txn, contactId,
+							MAX_RECORD_PAYLOAD_BYTES, maxLatency);
+					db.commitTransaction(txn);
+				} finally {
+					db.endTransaction(txn);
+				}
 				if (LOG.isLoggable(INFO))
 					LOG.info("Generated batch: " + (b != null));
 				if (b == null) decrementOutstandingQueries();

bramble-core/src/main/java/org/briarproject/bramble/sync/SyncModule.java

@@ -1,11 +1,23 @@
 package org.briarproject.bramble.sync;
 
+import org.briarproject.bramble.PoliteExecutor;
+import org.briarproject.bramble.api.crypto.CryptoComponent;
+import org.briarproject.bramble.api.crypto.CryptoExecutor;
+import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.DatabaseExecutor;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.sync.GroupFactory;
 import org.briarproject.bramble.api.sync.MessageFactory;
 import org.briarproject.bramble.api.sync.SyncRecordReaderFactory;
 import org.briarproject.bramble.api.sync.SyncRecordWriterFactory;
 import org.briarproject.bramble.api.sync.SyncSessionFactory;
+import org.briarproject.bramble.api.sync.ValidationManager;
+import org.briarproject.bramble.api.system.Clock;
 
+import java.util.concurrent.Executor;
+
+import javax.inject.Inject;
 import javax.inject.Singleton;
 
 import dagger.Module;
@@ -14,14 +26,29 @@ import dagger.Provides;
 @Module
 public class SyncModule {
 
+	public static class EagerSingletons {
+		@Inject
+		ValidationManager validationManager;
+	}
+
+	/**
+	 * The maximum number of validation tasks to delegate to the crypto
+	 * executor concurrently.
+	 * <p>
+	 * The number of available processors can change during the lifetime of the
+	 * JVM, so this is just a reasonable guess.
+	 */
+	private static final int MAX_CONCURRENT_VALIDATION_TASKS =
+			Math.max(1, Runtime.getRuntime().availableProcessors() - 1);
+
 	@Provides
-	GroupFactory provideGroupFactory(GroupFactoryImpl groupFactory) {
+	GroupFactory provideGroupFactory(CryptoComponent crypto) {
-		return groupFactory;
+		return new GroupFactoryImpl(crypto);
 	}
 
 	@Provides
-	MessageFactory provideMessageFactory(MessageFactoryImpl messageFactory) {
+	MessageFactory provideMessageFactory(CryptoComponent crypto) {
-		return messageFactory;
+		return new MessageFactoryImpl(crypto);
 	}
 
 	@Provides
@@ -38,8 +65,30 @@ public class SyncModule {
 
 	@Provides
 	@Singleton
-	SyncSessionFactory provideSyncSessionFactory(
+	SyncSessionFactory provideSyncSessionFactory(DatabaseComponent db,
-			SyncSessionFactoryImpl syncSessionFactory) {
+			@DatabaseExecutor Executor dbExecutor, EventBus eventBus,
-		return syncSessionFactory;
+			Clock clock, SyncRecordReaderFactory recordReaderFactory,
+			SyncRecordWriterFactory recordWriterFactory) {
+		return new SyncSessionFactoryImpl(db, dbExecutor, eventBus, clock,
+				recordReaderFactory, recordWriterFactory);
+	}
+
+	@Provides
+	@Singleton
+	ValidationManager provideValidationManager(
+			LifecycleManager lifecycleManager, EventBus eventBus,
+			ValidationManagerImpl validationManager) {
+		lifecycleManager.registerService(validationManager);
+		eventBus.addListener(validationManager);
+		return validationManager;
+	}
+
+	@Provides
+	@Singleton
+	@ValidationExecutor
+	Executor provideValidationExecutor(
+			@CryptoExecutor Executor cryptoExecutor) {
+		return new PoliteExecutor("ValidationExecutor", cryptoExecutor,
+				MAX_CONCURRENT_VALIDATION_TASKS);
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/sync/ValidationExecutor.java

@@ -1,4 +1,4 @@
-package org.briarproject.bramble.sync.validation;
+package org.briarproject.bramble.sync;
 
 import java.lang.annotation.Retention;
 import java.lang.annotation.Target;

bramble-core/src/main/java/org/briarproject/bramble/sync/ValidationManagerImpl.java

@@ -1,6 +1,5 @@
-package org.briarproject.bramble.sync.validation;
+package org.briarproject.bramble.sync;
 
-import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.db.DatabaseComponent;
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
@@ -18,11 +17,8 @@ import org.briarproject.bramble.api.sync.InvalidMessageException;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageContext;
 import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.bramble.api.sync.ValidationManager;
 import org.briarproject.bramble.api.sync.event.MessageAddedEvent;
-import org.briarproject.bramble.api.sync.validation.IncomingMessageHook;
-import org.briarproject.bramble.api.sync.validation.MessageState;
-import org.briarproject.bramble.api.sync.validation.MessageValidator;
-import org.briarproject.bramble.api.sync.validation.ValidationManager;
 import org.briarproject.bramble.api.versioning.ClientMajorVersion;
 
 import java.util.Collection;
@@ -40,9 +36,9 @@ import javax.inject.Inject;
 
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.api.sync.validation.MessageState.DELIVERED;
+import static org.briarproject.bramble.api.sync.ValidationManager.State.DELIVERED;
-import static org.briarproject.bramble.api.sync.validation.MessageState.INVALID;
+import static org.briarproject.bramble.api.sync.ValidationManager.State.INVALID;
-import static org.briarproject.bramble.api.sync.validation.MessageState.PENDING;
+import static org.briarproject.bramble.api.sync.ValidationManager.State.PENDING;
 import static org.briarproject.bramble.util.LogUtils.logException;
 
 @ThreadSafe
@@ -101,8 +97,14 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private void validateOutstandingMessages() {
 		try {
-			Queue<MessageId> unvalidated = new LinkedList<>(
+			Queue<MessageId> unvalidated = new LinkedList<>();
-					db.transactionWithResult(true, db::getMessagesToValidate));
+			Transaction txn = db.startTransaction(true);
+			try {
+				unvalidated.addAll(db.getMessagesToValidate(txn));
+				db.commitTransaction(txn);
+			} finally {
+				db.endTransaction(txn);
+			}
 			validateNextMessageAsync(unvalidated);
 		} catch (DbException e) {
 			logException(LOG, WARNING, e);
@@ -117,14 +119,18 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private void validateNextMessage(Queue<MessageId> unvalidated) {
 		try {
-			Pair<Message, Group> mg = db.transactionWithResult(true, txn -> {
+			Message m;
+			Group g;
+			Transaction txn = db.startTransaction(true);
+			try {
 				MessageId id = unvalidated.poll();
-				if (id == null) throw new AssertionError();
+				m = db.getMessage(txn, id);
-				Message m = db.getMessage(txn, id);
+				g = db.getGroup(txn, m.getGroupId());
-				Group g = db.getGroup(txn, m.getGroupId());
+				db.commitTransaction(txn);
-				return new Pair<>(m, g);
+			} finally {
-			});
+				db.endTransaction(txn);
-			validateMessageAsync(mg.getFirst(), mg.getSecond());
+			}
+			validateMessageAsync(m, g);
 			validateNextMessageAsync(unvalidated);
 		} catch (NoSuchMessageException e) {
 			LOG.info("Message removed before validation");
@@ -144,8 +150,14 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private void deliverOutstandingMessages() {
 		try {
-			Queue<MessageId> pending = new LinkedList<>(
+			Queue<MessageId> pending = new LinkedList<>();
-					db.transactionWithResult(true, db::getPendingMessages));
+			Transaction txn = db.startTransaction(true);
+			try {
+				pending.addAll(db.getPendingMessages(txn));
+				db.commitTransaction(txn);
+			} finally {
+				db.endTransaction(txn);
+			}
 			deliverNextPendingMessageAsync(pending);
 		} catch (DbException e) {
 			logException(LOG, WARNING, e);
@@ -160,24 +172,24 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private void deliverNextPendingMessage(Queue<MessageId> pending) {
 		try {
-			Queue<MessageId> toShare = new LinkedList<>();
+			boolean anyInvalid = false, allDelivered = true;
-			Queue<MessageId> invalidate = new LinkedList<>();
+			Queue<MessageId> toShare = null;
-			db.transaction(false, txn -> {
+			Queue<MessageId> invalidate = null;
-				boolean anyInvalid = false, allDelivered = true;
+			Transaction txn = db.startTransaction(false);
+			try {
 				MessageId id = pending.poll();
-				if (id == null) throw new AssertionError();
 				// Check if message is still pending
 				if (db.getMessageState(txn, id) == PENDING) {
 					// Check if dependencies are valid and delivered
-					Map<MessageId, MessageState> states =
+					Map<MessageId, State> states =
 							db.getMessageDependencies(txn, id);
-					for (Entry<MessageId, MessageState> e : states.entrySet()) {
+					for (Entry<MessageId, State> e : states.entrySet()) {
 						if (e.getValue() == INVALID) anyInvalid = true;
 						if (e.getValue() != DELIVERED) allDelivered = false;
 					}
 					if (anyInvalid) {
 						invalidateMessage(txn, id);
-						addDependentsToInvalidate(txn, id, invalidate);
+						invalidate = getDependentsToInvalidate(txn, id);
 					} else if (allDelivered) {
 						Message m = db.getMessage(txn, id);
 						Group g = db.getGroup(txn, m.getGroupId());
@@ -188,19 +200,22 @@ class ValidationManagerImpl implements ValidationManager, Service,
 						DeliveryResult result =
 								deliverMessage(txn, m, c, majorVersion, meta);
 						if (result.valid) {
-							addPendingDependents(txn, id, pending);
+							pending.addAll(getPendingDependents(txn, id));
 							if (result.share) {
 								db.setMessageShared(txn, id);
-								toShare.addAll(states.keySet());
+								toShare = new LinkedList<>(states.keySet());
 							}
 						} else {
-							addDependentsToInvalidate(txn, id, invalidate);
+							invalidate = getDependentsToInvalidate(txn, id);
 						}
 					}
 				}
-			});
+				db.commitTransaction(txn);
-			if (!invalidate.isEmpty()) invalidateNextMessageAsync(invalidate);
+			} finally {
-			if (!toShare.isEmpty()) shareNextMessageAsync(toShare);
+				db.endTransaction(txn);
+			}
+			if (invalidate != null) invalidateNextMessageAsync(invalidate);
+			if (toShare != null) shareNextMessageAsync(toShare);
 			deliverNextPendingMessageAsync(pending);
 		} catch (NoSuchMessageException e) {
 			LOG.info("Message removed before delivery");
@@ -249,19 +264,20 @@ class ValidationManagerImpl implements ValidationManager, Service,
 			MessageContext context) {
 		try {
 			MessageId id = m.getId();
-			Queue<MessageId> invalidate = new LinkedList<>();
+			boolean anyInvalid = false, allDelivered = true;
-			Queue<MessageId> pending = new LinkedList<>();
+			Queue<MessageId> invalidate = null;
-			Queue<MessageId> toShare = new LinkedList<>();
+			Queue<MessageId> pending = null;
-			db.transaction(false, txn -> {
+			Queue<MessageId> toShare = null;
-				boolean anyInvalid = false, allDelivered = true;
+			Transaction txn = db.startTransaction(false);
+			try {
 				// Check if message has any dependencies
 				Collection<MessageId> dependencies = context.getDependencies();
 				if (!dependencies.isEmpty()) {
 					db.addMessageDependencies(txn, m, dependencies);
 					// Check if dependencies are valid and delivered
-					Map<MessageId, MessageState> states =
+					Map<MessageId, State> states =
 							db.getMessageDependencies(txn, id);
-					for (Entry<MessageId, MessageState> e : states.entrySet()) {
+					for (Entry<MessageId, State> e : states.entrySet()) {
 						if (e.getValue() == INVALID) anyInvalid = true;
 						if (e.getValue() != DELIVERED) allDelivered = false;
 					}
@@ -269,7 +285,7 @@ class ValidationManagerImpl implements ValidationManager, Service,
 				if (anyInvalid) {
 					if (db.getMessageState(txn, id) != INVALID) {
 						invalidateMessage(txn, id);
-						addDependentsToInvalidate(txn, id, invalidate);
+						invalidate = getDependentsToInvalidate(txn, id);
 					}
 				} else {
 					Metadata meta = context.getMetadata();
@@ -278,22 +294,25 @@ class ValidationManagerImpl implements ValidationManager, Service,
 						DeliveryResult result =
 								deliverMessage(txn, m, c, majorVersion, meta);
 						if (result.valid) {
-							addPendingDependents(txn, id, pending);
+							pending = getPendingDependents(txn, id);
 							if (result.share) {
 								db.setMessageShared(txn, id);
-								toShare.addAll(dependencies);
+								toShare = new LinkedList<>(dependencies);
 							}
 						} else {
-							addDependentsToInvalidate(txn, id, invalidate);
+							invalidate = getDependentsToInvalidate(txn, id);
 						}
 					} else {
 						db.setMessageState(txn, id, PENDING);
 					}
 				}
-			});
+				db.commitTransaction(txn);
-			if (!invalidate.isEmpty()) invalidateNextMessageAsync(invalidate);
+			} finally {
-			if (!pending.isEmpty()) deliverNextPendingMessageAsync(pending);
+				db.endTransaction(txn);
-			if (!toShare.isEmpty()) shareNextMessageAsync(toShare);
+			}
+			if (invalidate != null) invalidateNextMessageAsync(invalidate);
+			if (pending != null) deliverNextPendingMessageAsync(pending);
+			if (toShare != null) shareNextMessageAsync(toShare);
 		} catch (NoSuchMessageException e) {
 			LOG.info("Message removed during validation");
 		} catch (NoSuchGroupException e) {
@@ -323,12 +342,14 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	}
 
 	@DatabaseExecutor
-	private void addPendingDependents(Transaction txn, MessageId m,
+	private Queue<MessageId> getPendingDependents(Transaction txn, MessageId m)
-			Queue<MessageId> pending) throws DbException {
+			throws DbException {
-		Map<MessageId, MessageState> states = db.getMessageDependents(txn, m);
+		Queue<MessageId> pending = new LinkedList<>();
-		for (Entry<MessageId, MessageState> e : states.entrySet()) {
+		Map<MessageId, State> states = db.getMessageDependents(txn, m);
+		for (Entry<MessageId, State> e : states.entrySet()) {
 			if (e.getValue() == PENDING) pending.add(e.getKey());
 		}
+		return pending;
 	}
 
 	private void shareOutstandingMessagesAsync() {
@@ -338,8 +359,14 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private void shareOutstandingMessages() {
 		try {
-			Queue<MessageId> toShare = new LinkedList<>(
+			Queue<MessageId> toShare = new LinkedList<>();
-					db.transactionWithResult(true, db::getMessagesToShare));
+			Transaction txn = db.startTransaction(true);
+			try {
+				toShare.addAll(db.getMessagesToShare(txn));
+				db.commitTransaction(txn);
+			} finally {
+				db.endTransaction(txn);
+			}
 			shareNextMessageAsync(toShare);
 		} catch (DbException e) {
 			logException(LOG, WARNING, e);
@@ -360,12 +387,15 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private void shareNextMessage(Queue<MessageId> toShare) {
 		try {
-			db.transaction(false, txn -> {
+			Transaction txn = db.startTransaction(false);
+			try {
 				MessageId id = toShare.poll();
-				if (id == null) throw new AssertionError();
 				db.setMessageShared(txn, id);
 				toShare.addAll(db.getMessageDependencies(txn, id).keySet());
-			});
+				db.commitTransaction(txn);
+			} finally {
+				db.endTransaction(txn);
+			}
 			shareNextMessageAsync(toShare);
 		} catch (NoSuchMessageException e) {
 			LOG.info("Message removed before sharing");
@@ -386,14 +416,17 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private void invalidateNextMessage(Queue<MessageId> invalidate) {
 		try {
-			db.transaction(false, txn -> {
+			Transaction txn = db.startTransaction(false);
+			try {
 				MessageId id = invalidate.poll();
-				if (id == null) throw new AssertionError();
 				if (db.getMessageState(txn, id) != INVALID) {
 					invalidateMessage(txn, id);
-					addDependentsToInvalidate(txn, id, invalidate);
+					invalidate.addAll(getDependentsToInvalidate(txn, id));
 				}
-			});
+				db.commitTransaction(txn);
+			} finally {
+				db.endTransaction(txn);
+			}
 			invalidateNextMessageAsync(invalidate);
 		} catch (NoSuchMessageException e) {
 			LOG.info("Message removed before invalidation");
@@ -412,12 +445,14 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	}
 
 	@DatabaseExecutor
-	private void addDependentsToInvalidate(Transaction txn,
+	private Queue<MessageId> getDependentsToInvalidate(Transaction txn,
-			MessageId m, Queue<MessageId> invalidate) throws DbException {
+			MessageId m) throws DbException {
-		Map<MessageId, MessageState> states = db.getMessageDependents(txn, m);
+		Queue<MessageId> invalidate = new LinkedList<>();
-		for (Entry<MessageId, MessageState> e : states.entrySet()) {
+		Map<MessageId, State> states = db.getMessageDependents(txn, m);
+		for (Entry<MessageId, State> e : states.entrySet()) {
 			if (e.getValue() != INVALID) invalidate.add(e.getKey());
 		}
+		return invalidate;
 	}
 
 	@Override
@@ -437,8 +472,14 @@ class ValidationManagerImpl implements ValidationManager, Service,
 	@DatabaseExecutor
 	private void loadGroupAndValidate(Message m) {
 		try {
-			Group g = db.transactionWithResult(true, txn ->
+			Group g;
-					db.getGroup(txn, m.getGroupId()));
+			Transaction txn = db.startTransaction(true);
+			try {
+				g = db.getGroup(txn, m.getGroupId());
+				db.commitTransaction(txn);
+			} finally {
+				db.endTransaction(txn);
+			}
 			validateMessageAsync(m, g);
 		} catch (NoSuchGroupException e) {
 			LOG.info("Group removed before validation");

bramble-core/src/main/java/org/briarproject/bramble/sync/validation/ValidationModule.java

@@ -1,53 +0,0 @@
-package org.briarproject.bramble.sync.validation;
-
-import org.briarproject.bramble.PoliteExecutor;
-import org.briarproject.bramble.api.crypto.CryptoExecutor;
-import org.briarproject.bramble.api.event.EventBus;
-import org.briarproject.bramble.api.lifecycle.LifecycleManager;
-import org.briarproject.bramble.api.sync.validation.ValidationManager;
-
-import java.util.concurrent.Executor;
-
-import javax.inject.Inject;
-import javax.inject.Singleton;
-
-import dagger.Module;
-import dagger.Provides;
-
-@Module
-public class ValidationModule {
-
-	public static class EagerSingletons {
-		@Inject
-		ValidationManager validationManager;
-	}
-
-	/**
-	 * The maximum number of validation tasks to delegate to the crypto
-	 * executor concurrently.
-	 * <p>
-	 * The number of available processors can change during the lifetime of the
-	 * JVM, so this is just a reasonable guess.
-	 */
-	private static final int MAX_CONCURRENT_VALIDATION_TASKS =
-			Math.max(1, Runtime.getRuntime().availableProcessors() - 1);
-
-	@Provides
-	@Singleton
-	ValidationManager provideValidationManager(
-			LifecycleManager lifecycleManager, EventBus eventBus,
-			ValidationManagerImpl validationManager) {
-		lifecycleManager.registerService(validationManager);
-		eventBus.addListener(validationManager);
-		return validationManager;
-	}
-
-	@Provides
-	@Singleton
-	@ValidationExecutor
-	Executor provideValidationExecutor(
-			@CryptoExecutor Executor cryptoExecutor) {
-		return new PoliteExecutor("ValidationExecutor", cryptoExecutor,
-				MAX_CONCURRENT_VALIDATION_TASKS);
-	}
-}

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

@@ -13,33 +13,32 @@ import java.util.logging.Logger;
 import javax.annotation.concurrent.Immutable;
 
 import static java.util.logging.Level.WARNING;
-import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.util.LogUtils.logException;
 
 @Immutable
 @NotNullByDefault
-class UnixSecureRandomProvider extends AbstractSecureRandomProvider {
+class LinuxSecureRandomProvider extends AbstractSecureRandomProvider {
 
 	private static final Logger LOG =
-			getLogger(UnixSecureRandomProvider.class.getName());
+			Logger.getLogger(LinuxSecureRandomProvider.class.getName());
 
 	private static final File RANDOM_DEVICE = new File("/dev/urandom");
 
 	private final AtomicBoolean seeded = new AtomicBoolean(false);
 	private final File outputDevice;
 
-	UnixSecureRandomProvider() {
+	LinuxSecureRandomProvider() {
 		this(RANDOM_DEVICE);
 	}
 
-	UnixSecureRandomProvider(File outputDevice) {
+	LinuxSecureRandomProvider(File outputDevice) {
 		this.outputDevice = outputDevice;
 	}
 
 	@Override
 	public Provider getProvider() {
 		if (!seeded.getAndSet(true)) writeSeed();
-		return new UnixProvider();
+		return new LinuxProvider();
 	}
 
 	protected void writeSeed() {
@@ -56,15 +55,15 @@ class UnixSecureRandomProvider extends AbstractSecureRandomProvider {
 	}
 
 	// Based on https://android-developers.googleblog.com/2013/08/some-securerandom-thoughts.html
-	private static class UnixProvider extends Provider {
+	private static class LinuxProvider extends Provider {
 
-		private UnixProvider() {
+		private LinuxProvider() {
-			super("UnixPRNG", 1.0, "A Unix-specific PRNG using /dev/urandom");
+			super("LinuxPRNG", 1.1, "A Linux-specific PRNG using /dev/urandom");
 			// Although /dev/urandom is not a SHA-1 PRNG, some callers
 			// explicitly request a SHA1PRNG SecureRandom and we need to
 			// prevent them from getting the default implementation whose
 			// output may have low entropy.
-			put("SecureRandom.SHA1PRNG", UnixSecureRandomSpi.class.getName());
+			put("SecureRandom.SHA1PRNG", LinuxSecureRandomSpi.class.getName());
 			put("SecureRandom.SHA1PRNG ImplementedIn", "Software");
 		}
 	}

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

@@ -10,24 +10,22 @@ import java.security.SecureRandomSpi;
 import java.util.logging.Logger;
 
 import static java.util.logging.Level.WARNING;
-import static java.util.logging.Logger.getLogger;
 import static org.briarproject.bramble.util.LogUtils.logException;
 
-public class UnixSecureRandomSpi extends SecureRandomSpi {
+public class LinuxSecureRandomSpi extends SecureRandomSpi {
 
 	private static final Logger LOG =
-			getLogger(UnixSecureRandomSpi.class.getName());
+			Logger.getLogger(LinuxSecureRandomSpi.class.getName());
 
 	private static final File RANDOM_DEVICE = new File("/dev/urandom");
 
 	private final File inputDevice, outputDevice;
 
-	@SuppressWarnings("WeakerAccess")
+	public LinuxSecureRandomSpi() {
-	public UnixSecureRandomSpi() {
 		this(RANDOM_DEVICE, RANDOM_DEVICE);
 	}
 
-	UnixSecureRandomSpi(File inputDevice, File outputDevice) {
+	LinuxSecureRandomSpi(File inputDevice, File outputDevice) {
 		this.inputDevice = inputDevice;
 		this.outputDevice = outputDevice;
 	}

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

@@ -72,7 +72,8 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 		for (DuplexPluginFactory f : pluginConfig.getDuplexFactories())
 			transports.put(f.getId(), f.getMaxLatency());
 		try {
-			db.transaction(false, txn -> {
+			Transaction txn = db.startTransaction(false);
+			try {
 				for (Contact c : db.getContacts(txn))
 					if (c.isActive()) activeContacts.put(c.getId(), true);
 				for (Entry<TransportId, Integer> e : transports.entrySet())
@@ -84,7 +85,10 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 					managers.put(e.getKey(), m);
 					m.start(txn);
 				}
-			});
+				db.commitTransaction(txn);
+			} finally {
+				db.endTransaction(txn);
+			}
 		} catch (DbException e) {
 			throw new ServiceException(e);
 		}
@@ -137,8 +141,15 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 			if (LOG.isLoggable(INFO)) LOG.info("No key manager for " + t);
 			return null;
 		}
-		return db.transactionWithNullableResult(false, txn ->
+		StreamContext ctx;
-				m.getStreamContext(txn, c));
+		Transaction txn = db.startTransaction(false);
+		try {
+			ctx = m.getStreamContext(txn, c);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
+		return ctx;
 	}
 
 	@Override
@@ -149,8 +160,15 @@ class KeyManagerImpl implements KeyManager, Service, EventListener {
 			if (LOG.isLoggable(INFO)) LOG.info("No key manager for " + t);
 			return null;
 		}
-		return db.transactionWithNullableResult(false, txn ->
+		StreamContext ctx;
-				m.getStreamContext(txn, tag));
+		Transaction txn = db.startTransaction(false);
+		try {
+			ctx = m.getStreamContext(txn, tag);
+			db.commitTransaction(txn);
+		} finally {
+			db.endTransaction(txn);
+		}
+		return ctx;
 	}
 
 	@Override

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

@@ -162,7 +162,13 @@ class TransportKeyManagerImpl implements TransportKeyManager {
 	private void rotateKeys() {
 		dbExecutor.execute(() -> {
 			try {
-				db.transaction(false, this::rotateKeys);
+				Transaction txn = db.startTransaction(false);
+				try {
+					rotateKeys(txn);
+					db.commitTransaction(txn);
+				} finally {
+					db.endTransaction(txn);
+				}
 			} catch (DbException e) {
 				logException(LOG, WARNING, e);
 			}

bramble-core/src/main/java/org/briarproject/bramble/versioning/ClientVersioningManagerImpl.java

@@ -23,7 +23,7 @@ import org.briarproject.bramble.api.sync.GroupId;
 import org.briarproject.bramble.api.sync.InvalidMessageException;
 import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageId;
-import org.briarproject.bramble.api.sync.validation.IncomingMessageHook;
+import org.briarproject.bramble.api.sync.ValidationManager.IncomingMessageHook;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.versioning.ClientMajorVersion;
 import org.briarproject.bramble.api.versioning.ClientVersioningManager;
@@ -123,12 +123,16 @@ class ClientVersioningManagerImpl implements ClientVersioningManager, Client,
 		List<ClientVersion> versions = new ArrayList<>(clients);
 		Collections.sort(versions);
 		try {
-			db.transaction(false, txn -> {
+			Transaction txn = db.startTransaction(false);
+			try {
 				if (updateClientVersions(txn, versions)) {
 					for (Contact c : db.getContacts(txn))
 						clientVersionsUpdated(txn, c, versions);
 				}
-			});
+				db.commitTransaction(txn);
+			} finally {
+				db.endTransaction(txn);
+			}
 		} catch (DbException e) {
 			throw new ServiceException(e);
 		}

bramble-core/src/main/java/org/briarproject/bramble/versioning/VersioningModule.java

@@ -4,7 +4,7 @@ import org.briarproject.bramble.api.client.ClientHelper;
 import org.briarproject.bramble.api.contact.ContactManager;
 import org.briarproject.bramble.api.data.MetadataEncoder;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
-import org.briarproject.bramble.api.sync.validation.ValidationManager;
+import org.briarproject.bramble.api.sync.ValidationManager;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.versioning.ClientVersioningManager;
 

bramble-core/src/main/resources/bridges

@@ -1,4 +1,8 @@
-Bridge obfs4 78.46.188.239:37356 5A2D2F4158D0453E00C7C176978D3F41D69C45DB cert=3c0SwxpOisbohNxEc4tb875RVW8eOu1opRTVXJhafaKA/PNNtI7ElQIVOVZg1AdL5bxGCw iat-mode=0
+Bridge 131.252.210.150:8081 0E858AC201BF0F3FA3C462F64844CBFFC7297A42
-Bridge obfs4 52.15.78.72:9443 02069A3C5362476936B62BA6F5ACC41ABD573A9B cert=ijYG/OKc7kqu2YzKNFfeXN7/BG2BOgfEP2KyYEiGDQthnHbsOiTWHeIG0WJVW+BckzDgKw iat-mode=0
+Bridge 67.205.189.122:8443 12D64D5D44E20169585E7378580C0D33A872AD98
-Bridge obfs4 13.58.29.242:9443 0C58939A77DA6B6B29D4B5236A75865659607AE0 cert=OylWIEHb/ezpq1zWxW0sgKRn+9ARH2eOcQOZ8/Gew+4l+oKOhQ2jUX/Y+FSl61JorXZUWA iat-mode=0
+Bridge 45.32.148.146:8443 0CE016FB2462D8BF179AE71F7D702D09DEAC3F1D
-Bridge obfs4 45.33.37.112:9443 60A609BB4ABE8D46E634AE81ED29ADAB7776B399 cert=t5v19WmNv5Sc2YPNr8RQids365W7MY8zJwQVkOxBjUMFomMWARDzsbYpcWLLcw0J9Gm+BQ iat-mode=0
+Bridge 148.251.90.59:7510 019F727CA6DCA6CA5C90B55E477B7D87981E75BC
+Bridge 45.55.1.74:8443 6F18FEFBB0CAECD5ABA755312FCCB34FC11A7AB8
+Bridge 85.229.131.78:444 50E433CCC5FEC11CC34CB4D92033561E065EA106
+Bridge 178.62.62.193:8443 391B1F9B6A28A1C5FAE1872283985F975E5DB029
+Bridge 45.76.29.92:8443 ECF1DD51A46FDEF2C50CED992EEEAE8DED18DA0C

bramble-core/src/test/java/org/briarproject/bramble/client/ClientHelperImplTest.java

@@ -22,7 +22,6 @@ import org.briarproject.bramble.api.sync.Message;
 import org.briarproject.bramble.api.sync.MessageFactory;
 import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.bramble.test.BrambleTestCase;
-import org.briarproject.bramble.test.DbExpectations;
 import org.briarproject.bramble.util.StringUtils;
 import org.jmock.Expectations;
 import org.jmock.Mockery;
@@ -86,11 +85,14 @@ public class ClientHelperImplTest extends BrambleTestCase {
 		boolean shared = new Random().nextBoolean();
 		Transaction txn = new Transaction(null, false);
 
-		context.checking(new DbExpectations() {{
+		context.checking(new Expectations() {{
-			oneOf(db).transaction(with(false), withDbRunnable(txn));
+			oneOf(db).startTransaction(false);
+			will(returnValue(txn));
 			oneOf(metadataEncoder).encode(dictionary);
 			will(returnValue(metadata));
 			oneOf(db).addLocalMessage(txn, message, metadata, shared);
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
 		}});
 
 		clientHelper.addLocalMessage(message, dictionary, shared);
@@ -114,10 +116,13 @@ public class ClientHelperImplTest extends BrambleTestCase {
 		Transaction txn = new Transaction(null, true);
 
 		expectToList(true);
-		context.checking(new DbExpectations() {{
+		context.checking(new Expectations() {{
-			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
+			oneOf(db).startTransaction(true);
+			will(returnValue(txn));
 			oneOf(db).getMessage(txn, messageId);
 			will(returnValue(message));
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
 		}});
 
 		clientHelper.getMessageAsList(messageId);
@@ -128,12 +133,15 @@ public class ClientHelperImplTest extends BrambleTestCase {
 	public void testGetGroupMetadataAsDictionary() throws Exception {
 		Transaction txn = new Transaction(null, true);
 
-		context.checking(new DbExpectations() {{
+		context.checking(new Expectations() {{
-			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
+			oneOf(db).startTransaction(true);
+			will(returnValue(txn));
 			oneOf(db).getGroupMetadata(txn, groupId);
 			will(returnValue(metadata));
 			oneOf(metadataParser).parse(metadata);
 			will(returnValue(dictionary));
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
 		}});
 
 		assertEquals(dictionary,
@@ -145,12 +153,15 @@ public class ClientHelperImplTest extends BrambleTestCase {
 	public void testGetMessageMetadataAsDictionary() throws Exception {
 		Transaction txn = new Transaction(null, true);
 
-		context.checking(new DbExpectations() {{
+		context.checking(new Expectations() {{
-			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
+			oneOf(db).startTransaction(true);
+			will(returnValue(txn));
 			oneOf(db).getMessageMetadata(txn, messageId);
 			will(returnValue(metadata));
 			oneOf(metadataParser).parse(metadata);
 			will(returnValue(dictionary));
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
 		}});
 
 		assertEquals(dictionary,
@@ -164,12 +175,15 @@ public class ClientHelperImplTest extends BrambleTestCase {
 		map.put(messageId, dictionary);
 		Transaction txn = new Transaction(null, true);
 
-		context.checking(new DbExpectations() {{
+		context.checking(new Expectations() {{
-			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
+			oneOf(db).startTransaction(true);
+			will(returnValue(txn));
 			oneOf(db).getMessageMetadata(txn, groupId);
 			will(returnValue(Collections.singletonMap(messageId, metadata)));
 			oneOf(metadataParser).parse(metadata);
 			will(returnValue(dictionary));
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
 		}});
 
 		assertEquals(map, clientHelper.getMessageMetadataAsDictionary(groupId));
@@ -186,14 +200,17 @@ public class ClientHelperImplTest extends BrambleTestCase {
 		queryMetadata.put("query", getRandomBytes(42));
 		Transaction txn = new Transaction(null, true);
 
-		context.checking(new DbExpectations() {{
+		context.checking(new Expectations() {{
-			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
+			oneOf(db).startTransaction(true);
+			will(returnValue(txn));
 			oneOf(metadataEncoder).encode(query);
 			will(returnValue(queryMetadata));
 			oneOf(db).getMessageMetadata(txn, groupId, queryMetadata);
 			will(returnValue(Collections.singletonMap(messageId, metadata)));
 			oneOf(metadataParser).parse(metadata);
 			will(returnValue(dictionary));
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
 		}});
 
 		assertEquals(map,
@@ -205,11 +222,14 @@ public class ClientHelperImplTest extends BrambleTestCase {
 	public void testMergeGroupMetadata() throws Exception {
 		Transaction txn = new Transaction(null, false);
 
-		context.checking(new DbExpectations() {{
+		context.checking(new Expectations() {{
-			oneOf(db).transaction(with(false), withDbRunnable(txn));
+			oneOf(db).startTransaction(false);
+			will(returnValue(txn));
 			oneOf(metadataEncoder).encode(dictionary);
 			will(returnValue(metadata));
 			oneOf(db).mergeGroupMetadata(txn, groupId, metadata);
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
 		}});
 
 		clientHelper.mergeGroupMetadata(groupId, dictionary);
@@ -220,11 +240,14 @@ public class ClientHelperImplTest extends BrambleTestCase {
 	public void testMergeMessageMetadata() throws Exception {
 		Transaction txn = new Transaction(null, false);
 
-		context.checking(new DbExpectations() {{
+		context.checking(new Expectations() {{
-			oneOf(db).transaction(with(false), withDbRunnable(txn));
+			oneOf(db).startTransaction(false);
+			will(returnValue(txn));
 			oneOf(metadataEncoder).encode(dictionary);
 			will(returnValue(metadata));
 			oneOf(db).mergeMessageMetadata(txn, messageId, metadata);
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
 		}});
 
 		clientHelper.mergeMessageMetadata(messageId, dictionary);

bramble-core/src/test/java/org/briarproject/bramble/contact/ContactManagerImplTest.java

@@ -5,17 +5,12 @@ import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.ContactManager;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.db.DatabaseComponent;
-import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.NoSuchContactException;
 import org.briarproject.bramble.api.db.Transaction;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
-import org.briarproject.bramble.api.identity.AuthorInfo;
-import org.briarproject.bramble.api.identity.IdentityManager;
-import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.transport.KeyManager;
 import org.briarproject.bramble.test.BrambleMockTestCase;
-import org.briarproject.bramble.test.DbExpectations;
 import org.jmock.Expectations;
 import org.jmock.Mockery;
 import org.junit.Test;
@@ -25,20 +20,10 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.Random;
 
-import static java.util.Collections.emptyList;
-import static java.util.Collections.singletonList;
-import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.OURSELVES;
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.UNKNOWN;
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.UNVERIFIED;
-import static org.briarproject.bramble.api.identity.AuthorInfo.Status.VERIFIED;
 import static org.briarproject.bramble.test.TestUtils.getAuthor;
-import static org.briarproject.bramble.test.TestUtils.getLocalAuthor;
 import static org.briarproject.bramble.test.TestUtils.getRandomId;
 import static org.briarproject.bramble.test.TestUtils.getSecretKey;
-import static org.briarproject.bramble.util.StringUtils.getRandomString;
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 
 public class ContactManagerImplTest extends BrambleMockTestCase {
@@ -46,20 +31,16 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	private final Mockery context = new Mockery();
 	private final DatabaseComponent db = context.mock(DatabaseComponent.class);
 	private final KeyManager keyManager = context.mock(KeyManager.class);
-	private final IdentityManager identityManager =
-			context.mock(IdentityManager.class);
 	private final ContactManager contactManager;
 	private final ContactId contactId = new ContactId(42);
 	private final Author remote = getAuthor();
 	private final AuthorId local = new AuthorId(getRandomId());
-	private final LocalAuthor localAuthor = getLocalAuthor();
-	private final String alias = getRandomString(MAX_AUTHOR_NAME_LENGTH);
 	private final boolean verified = false, active = true;
 	private final Contact contact =
-			new Contact(contactId, remote, local, alias, verified, active);
+			new Contact(contactId, remote, local, verified, active);
 
 	public ContactManagerImplTest() {
-		contactManager = new ContactManagerImpl(db, keyManager, identityManager);
+		contactManager = new ContactManagerImpl(db, keyManager);
 	}
 
 	@Test
@@ -69,14 +50,17 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 		boolean alice = new Random().nextBoolean();
 		Transaction txn = new Transaction(null, false);
 
-		context.checking(new DbExpectations() {{
+		context.checking(new Expectations() {{
-			oneOf(db).transactionWithResult(with(false), withDbCallable(txn));
+			oneOf(db).startTransaction(false);
+			will(returnValue(txn));
 			oneOf(db).addContact(txn, remote, local, verified, active);
 			will(returnValue(contactId));
 			oneOf(keyManager).addContact(txn, contactId, master, timestamp,
 					alice, active);
 			oneOf(db).getContact(txn, contactId);
 			will(returnValue(contact));
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
 		}});
 
 		assertEquals(contactId, contactManager.addContact(remote, local,
@@ -86,10 +70,13 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	@Test
 	public void testGetContact() throws Exception {
 		Transaction txn = new Transaction(null, true);
-		context.checking(new DbExpectations() {{
+		context.checking(new Expectations() {{
-			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
+			oneOf(db).startTransaction(true);
+			will(returnValue(txn));
 			oneOf(db).getContact(txn, contactId);
 			will(returnValue(contact));
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
 		}});
 
 		assertEquals(contact, contactManager.getContact(contactId));
@@ -99,10 +86,13 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	public void testGetContactByAuthor() throws Exception {
 		Transaction txn = new Transaction(null, true);
 		Collection<Contact> contacts = Collections.singleton(contact);
-		context.checking(new DbExpectations() {{
+		context.checking(new Expectations() {{
-			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
+			oneOf(db).startTransaction(true);
+			will(returnValue(txn));
 			oneOf(db).getContactsByAuthorId(txn, remote.getId());
 			will(returnValue(contacts));
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
 		}});
 
 		assertEquals(contact, contactManager.getContact(remote.getId(), local));
@@ -111,10 +101,12 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	@Test(expected = NoSuchContactException.class)
 	public void testGetContactByUnknownAuthor() throws Exception {
 		Transaction txn = new Transaction(null, true);
-		context.checking(new DbExpectations() {{
+		context.checking(new Expectations() {{
-			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
+			oneOf(db).startTransaction(true);
+			will(returnValue(txn));
 			oneOf(db).getContactsByAuthorId(txn, remote.getId());
-			will(returnValue(emptyList()));
+			will(returnValue(Collections.emptyList()));
+			oneOf(db).endTransaction(txn);
 		}});
 
 		contactManager.getContact(remote.getId(), local);
@@ -124,26 +116,30 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	public void testGetContactByUnknownLocalAuthor() throws Exception {
 		Transaction txn = new Transaction(null, true);
 		Collection<Contact> contacts = Collections.singleton(contact);
-		context.checking(new DbExpectations() {{
+		context.checking(new Expectations() {{
-			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
+			oneOf(db).startTransaction(true);
+			will(returnValue(txn));
 			oneOf(db).getContactsByAuthorId(txn, remote.getId());
 			will(returnValue(contacts));
+			oneOf(db).endTransaction(txn);
 		}});
 
 		contactManager.getContact(remote.getId(), new AuthorId(getRandomId()));
 	}
 
 	@Test
-	public void testGetActiveContacts() throws Exception {
+	public void testActiveContacts() throws Exception {
 		Collection<Contact> activeContacts = Collections.singletonList(contact);
 		Collection<Contact> contacts = new ArrayList<>(activeContacts);
-		contacts.add(new Contact(new ContactId(3), remote, local, alias, true,
+		contacts.add(new Contact(new ContactId(3), remote, local, true, false));
-				false));
 		Transaction txn = new Transaction(null, true);
-		context.checking(new DbExpectations() {{
+		context.checking(new Expectations() {{
-			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
+			oneOf(db).startTransaction(true);
+			will(returnValue(txn));
 			oneOf(db).getContacts(txn);
 			will(returnValue(contacts));
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
 		}});
 
 		assertEquals(activeContacts, contactManager.getActiveContacts());
@@ -152,11 +148,14 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 	@Test
 	public void testRemoveContact() throws Exception {
 		Transaction txn = new Transaction(null, false);
-		context.checking(new DbExpectations() {{
+		context.checking(new Expectations() {{
-			oneOf(db).transaction(with(false), withDbRunnable(txn));
+			oneOf(db).startTransaction(false);
+			will(returnValue(txn));
 			oneOf(db).getContact(txn, contactId);
 			will(returnValue(contact));
 			oneOf(db).removeContact(txn, contactId);
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
 		}});
 
 		contactManager.removeContact(contactId);
@@ -172,108 +171,19 @@ public class ContactManagerImplTest extends BrambleMockTestCase {
 		contactManager.setContactActive(txn, contactId, active);
 	}
 
-	@Test
-	public void testSetContactAlias() throws Exception {
-		Transaction txn = new Transaction(null, false);
-		context.checking(new DbExpectations() {{
-			oneOf(db).transaction(with(false), withDbRunnable(txn));
-			oneOf(db).setContactAlias(txn, contactId, alias);
-		}});
-
-		contactManager.setContactAlias(contactId, alias);
-	}
-
-	@Test(expected = IllegalArgumentException.class)
-	public void testSetContactAliasTooLong() throws Exception {
-		Transaction txn = new Transaction(null, false);
-		contactManager.setContactAlias(txn, contactId,
-				getRandomString(MAX_AUTHOR_NAME_LENGTH + 1));
-	}
-
 	@Test
 	public void testContactExists() throws Exception {
 		Transaction txn = new Transaction(null, true);
-		context.checking(new DbExpectations() {{
+		context.checking(new Expectations() {{
-			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
+			oneOf(db).startTransaction(true);
+			will(returnValue(txn));
 			oneOf(db).containsContact(txn, remote.getId(), local);
 			will(returnValue(true));
+			oneOf(db).commitTransaction(txn);
+			oneOf(db).endTransaction(txn);
 		}});
 
 		assertTrue(contactManager.contactExists(remote.getId(), local));
 	}
 
-	@Test
-	public void testGetAuthorInfo() throws Exception {
-		Transaction txn = new Transaction(null, true);
-		Collection<Contact> contacts = singletonList(
-				new Contact(new ContactId(1), remote, localAuthor.getId(),
-						alias, false, true));
-
-		context.checking(new DbExpectations() {{
-			oneOf(db).transactionWithResult(with(true), withDbCallable(txn));
-			oneOf(identityManager).getLocalAuthor(txn);
-			will(returnValue(localAuthor));
-			oneOf(db).getContactsByAuthorId(txn, remote.getId());
-			will(returnValue(contacts));
-		}});
-		AuthorInfo authorInfo =
-				contactManager.getAuthorInfo(txn, remote.getId());
-		assertEquals(UNVERIFIED, authorInfo.getStatus());
-		assertEquals(alias, contact.getAlias());
-	}
-
-	@Test
-	public void testGetAuthorInfoTransaction() throws DbException {
-		Transaction txn = new Transaction(null, true);
-
-		// check unknown author
-		context.checking(new Expectations() {{
-			oneOf(identityManager).getLocalAuthor(txn);
-			will(returnValue(localAuthor));
-			oneOf(db).getContactsByAuthorId(txn, remote.getId());
-			will(returnValue(emptyList()));
-		}});
-		AuthorInfo authorInfo =
-				contactManager.getAuthorInfo(txn, remote.getId());
-		assertEquals(UNKNOWN, authorInfo.getStatus());
-		assertNull(authorInfo.getAlias());
-
-		// check unverified contact
-		Collection<Contact> contacts = singletonList(
-				new Contact(new ContactId(1), remote, localAuthor.getId(),
-						alias, false, true));
-		checkAuthorInfoContext(txn, remote.getId(), contacts);
-		authorInfo = contactManager.getAuthorInfo(txn, remote.getId());
-		assertEquals(UNVERIFIED, authorInfo.getStatus());
-		assertEquals(alias, contact.getAlias());
-
-		// check verified contact
-		contacts = singletonList(new Contact(new ContactId(1), remote,
-				localAuthor.getId(), alias, true, true));
-		checkAuthorInfoContext(txn, remote.getId(), contacts);
-		authorInfo = contactManager.getAuthorInfo(txn, remote.getId());
-		assertEquals(VERIFIED, authorInfo.getStatus());
-		assertEquals(alias, contact.getAlias());
-
-		// check ourselves
-		context.checking(new Expectations() {{
-			oneOf(identityManager).getLocalAuthor(txn);
-			will(returnValue(localAuthor));
-			never(db).getContactsByAuthorId(txn, remote.getId());
-		}});
-		authorInfo = contactManager.getAuthorInfo(txn, localAuthor.getId());
-		assertEquals(OURSELVES, authorInfo.getStatus());
-		assertNull(authorInfo.getAlias());
-	}
-
-	private void checkAuthorInfoContext(Transaction txn, AuthorId authorId,
-			Collection<Contact> contacts) throws DbException {
-		context.checking(new Expectations() {{
-			oneOf(identityManager).getLocalAuthor(txn);
-			will(returnValue(localAuthor));
-			oneOf(db).getContactsByAuthorId(txn, authorId);
-			will(returnValue(contacts));
-		}});
-	}
-
 }

bramble-core/src/test/java/org/briarproject/bramble/data/BdfReaderImplFuzzingTest.java

@@ -1,41 +0,0 @@
-package org.briarproject.bramble.data;
-
-import org.briarproject.bramble.test.BrambleTestCase;
-import org.junit.Before;
-import org.junit.Test;
-
-import java.io.ByteArrayInputStream;
-import java.util.Random;
-
-import static org.briarproject.bramble.api.data.BdfReader.DEFAULT_MAX_BUFFER_SIZE;
-import static org.briarproject.bramble.api.data.BdfReader.DEFAULT_NESTED_LIMIT;
-import static org.briarproject.bramble.test.TestUtils.isOptionalTestEnabled;
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assume.assumeTrue;
-
-public class BdfReaderImplFuzzingTest extends BrambleTestCase {
-
-	@Before
-	public void setUp() {
-		assumeTrue(isOptionalTestEnabled(BdfReaderImplFuzzingTest.class));
-	}
-
-	@Test
-	public void testStringFuzzing() throws Exception {
-		Random random = new Random();
-		byte[] buf = new byte[22];
-		ByteArrayInputStream in = new ByteArrayInputStream(buf);
-		for (int i = 0; i < 100_000_000; i++) {
-			random.nextBytes(buf);
-			buf[0] = 0x41; // String with 1-byte length
-			buf[1] = 0x14; // Length 20 bytes
-			in.reset();
-			BdfReaderImpl r = new BdfReaderImpl(in, DEFAULT_NESTED_LIMIT,
-					DEFAULT_MAX_BUFFER_SIZE);
-			int length = r.readString().length();
-			assertTrue(length >= 0);
-			assertTrue(length <= 20);
-			assertTrue(r.eof());
-		}
-	}
-}