Bump version numbers for beta release.

This is a fix for a backporting mistake.

.gitlab-ci.yml

@@ -6,9 +6,18 @@ cache:
     - .gradle/caches
 
 before_script:
+  - set -e
   - export GRADLE_USER_HOME=$PWD/.gradle
-#  - export ANDROID_COMPILE_SDK=`sed -n 's,.*compileSdkVersion\s*\([0-9][0-9]*\).*,\1,p' app/build.gradle`
-#  - echo y | android --silent update sdk --no-ui --filter android-${ANDROID_COMPILE_SDK}
+  # Accept the license for the Android build tools
+  - echo y | /opt/android-sdk/tools/bin/sdkmanager "build-tools;26.0.2"
+  # Download OpenJDK 6 so we can compile against its standard library
+  - JDK_FILE=openjdk-6-jre-headless_6b38-1.13.10-1~deb7u1_amd64.deb
+  - if [ ! -d openjdk ]
+  - then
+  - wget -q http://ftp.uk.debian.org/debian/pool/main/o/openjdk-6/$JDK_FILE
+  - dpkg-deb -x $JDK_FILE openjdk
+  - fi
+  - export JAVA_6_HOME=$PWD/openjdk/usr/lib/jvm/java-6-openjdk-amd64
 
 test:
   script:

bramble-android/build.gradle

@@ -6,99 +6,90 @@ apply plugin: 'witness'
 apply plugin: 'de.undercouch.download'
 
 android {
-	compileSdkVersion 23
-	buildToolsVersion "23.0.3"
+	compileSdkVersion 27
+	buildToolsVersion '26.0.2'
 
 	defaultConfig {
 		minSdkVersion 14
-		targetSdkVersion 22
-		versionCode 1609
-		versionName "0.16.9"
+		targetSdkVersion 26
+		versionCode 1619
+		versionName "0.16.19"
 		consumerProguardFiles 'proguard-rules.txt'
 	}
 
 	compileOptions {
-		sourceCompatibility JavaVersion.VERSION_1_7
-		targetCompatibility JavaVersion.VERSION_1_7
+		sourceCompatibility JavaVersion.VERSION_1_8
+		targetCompatibility JavaVersion.VERSION_1_8
 	}
 }
 
 dependencies {
-	compile project(':bramble-core')
-	compile fileTree(dir: 'libs', include: '*.jar')
-	provided 'javax.annotation:jsr250-api:1.0'
+	implementation project(path: ':bramble-core', configuration: 'default')
+	implementation fileTree(dir: 'libs', include: '*.jar')
+
+	annotationProcessor 'com.google.dagger:dagger-compiler:2.0.2'
+
+	compileOnly 'javax.annotation:jsr250-api:1.0'
 }
 
-def torBinaryDir = 'src/main/res/raw'
-
-task downloadTorGeoIp(type: Download) {
-	src 'https://briarproject.org/build/geoip-2017-05-02.zip'
-	dest "$torBinaryDir/geoip.zip"
-	onlyIfNewer true
+dependencyVerification {
+	verify = [
+			'com.google.code.findbugs:jsr305:3.0.2:jsr305-3.0.2.jar:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
+			'com.google.dagger:dagger-compiler:2.0.2:dagger-compiler-2.0.2.jar:b74bc9de063dd4c6400b232231f2ef5056145b8fbecbf5382012007dd1c071b3',
+			'com.google.dagger:dagger-producers:2.0-beta:dagger-producers-2.0-beta.jar:99ec15e8a0507ba569e7655bc1165ee5e5ca5aa914b3c8f7e2c2458f724edd6b',
+			'com.google.dagger:dagger:2.0.2:dagger-2.0.2.jar:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
+			'com.google.guava:guava:18.0:guava-18.0.jar:d664fbfc03d2e5ce9cab2a44fb01f1d0bf9dfebeccc1a473b1f9ea31f79f6f99',
+			'com.h2database:h2:1.4.192:h2-1.4.192.jar:225b22e9857235c46c93861410b60b8c81c10dc8985f4faf188985ba5445126c',
+			'com.madgag.spongycastle:core:1.58.0.0:core-1.58.0.0.jar:199617dd5698c5a9312b898c0a4cec7ce9dd8649d07f65d91629f58229d72728',
+			'javax.annotation:jsr250-api:1.0:jsr250-api-1.0.jar:a1a922d0d9b6d183ed3800dfac01d1e1eb159f0e8c6f94736931c1def54a941f',
+			'javax.inject:javax.inject:1:javax.inject-1.jar:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
+			'org.bitlet:weupnp:0.1.4:weupnp-0.1.4.jar:88df7e6504929d00bdb832863761385c68ab92af945b04f0770b126270a444fb',
+			'org.jacoco:org.jacoco.agent:0.7.4.201502262128:org.jacoco.agent-0.7.4.201502262128-runtime.jar:e357a0f1d573c2f702a273992b1b6cb661734f66311854efb3778a888515c5b5',
+			'org.jacoco:org.jacoco.agent:0.7.4.201502262128:org.jacoco.agent-0.7.4.201502262128.jar:47b4bec6df11a1118da3953da8b9fa1e7079d6fec857faa1a3cf912e53a6fd4e',
+			'org.jacoco:org.jacoco.ant:0.7.4.201502262128:org.jacoco.ant-0.7.4.201502262128.jar:013ce2a68ba57a3c59215ae0dec4df3498c078062a38c3b94c841fc14450f283',
+			'org.jacoco:org.jacoco.core:0.7.4.201502262128:org.jacoco.core-0.7.4.201502262128.jar:ec4c74554312fac5116350164786f91b35c9e082fa4ea598bfa42b5db05d7abb',
+			'org.jacoco:org.jacoco.report:0.7.4.201502262128:org.jacoco.report-0.7.4.201502262128.jar:7a3554c605e088e7e323b1084656243f0444fa353e2f2dee1f1a4204eb64ff09',
+			'org.ow2.asm:asm-debug-all:5.0.1:asm-debug-all-5.0.1.jar:4734de5b515a454b0096db6971fb068e5f70e6f10bbee2b3bd2fdfe5d978ed57',
+	]
 }
 
-task downloadTorBinaryArm(type: Download) {
-	src 'https://briarproject.org/build/tor-0.2.9.11-arm.zip'
-	dest "$torBinaryDir/tor_arm.zip"
-	onlyIfNewer true
+ext.torBinaryDir = 'src/main/res/raw'
+ext.torVersion = '0.2.9.14'
+ext.geoipVersion = '2017-11-06'
+ext.torDownloadUrl = 'https://briarproject.org/build/'
+
+def torBinaries = [
+		"tor_arm"    : '1710ea6c47b7f4c1a88bdf4858c7893837635db10e8866854eed8d61629f50e8',
+		"tor_arm_pie": '974e6949507db8fa2ea45231817c2c3677ed4ccf5488a2252317d744b0be1917',
+		"tor_x86"    : '3a5e45b3f051fcda9353b098b7086e762ffe7ba9242f7d7c8bf6523faaa8b1e9',
+		"tor_x86_pie": 'd1d96d8ce1a4b68accf04850185780d10cd5563d3552f7e1f040f8ca32cb4e51',
+		"geoip"      : '8239b98374493529a29096e45fc5877d4d6fdad0146ad8380b291f90d61484ea'
+]
+
+def downloadBinary(name) {
+	return tasks.create("downloadBinary${name}", Download) {
+		src "${torDownloadUrl}${name}.zip"
+				.replace('tor_', "tor-${torVersion}-")
+				.replace('geoip', "geoip-${geoipVersion}")
+				.replaceAll('_', '-')
+		dest "${torBinaryDir}/${name}.zip"
+		onlyIfNewer true
+	}
 }
 
-task downloadTorBinaryArmPie(type: Download) {
-	src 'https://briarproject.org/build/tor-0.2.9.11-arm-pie.zip'
-	dest "$torBinaryDir/tor_arm_pie.zip"
-	onlyIfNewer true
-}
-
-task downloadTorBinaryX86(type: Download) {
-	src 'https://briarproject.org/build/tor-0.2.9.11-x86.zip'
-	dest "$torBinaryDir/tor_x86.zip"
-	onlyIfNewer true
-}
-
-task downloadTorBinaryX86Pie(type: Download) {
-	src 'https://briarproject.org/build/tor-0.2.9.11-x86-pie.zip'
-	dest "$torBinaryDir/tor_x86_pie.zip"
-	onlyIfNewer true
-}
-
-task verifyTorGeoIp(type: Verify, dependsOn: 'downloadTorGeoIp') {
-	src "$torBinaryDir/geoip.zip"
-	algorithm 'SHA-256'
-	checksum '51f4d1272fb867e1f3b36b67a584e2a33c40b40f62305457d799fd399cd77c9b'
-}
-
-task verifyTorBinaryArm(type: Verify, dependsOn: 'downloadTorBinaryArm') {
-	src "$torBinaryDir/tor_arm.zip"
-	algorithm 'SHA-256'
-	checksum '1da6008663a8ad98b349e62acbbf42c379f65ec504fa467cb119c187cd5a4c6b'
-}
-
-task verifyTorBinaryArmPie(type: Verify, dependsOn: 'downloadTorBinaryArmPie') {
-	src "$torBinaryDir/tor_arm_pie.zip"
-	algorithm 'SHA-256'
-	checksum 'eb061f880829e05f104690ac744848133f2dacef04759d425a2cff0df32c271e'
-}
-
-task verifyTorBinaryX86(type: Verify, dependsOn: 'downloadTorBinaryX86') {
-	src "$torBinaryDir/tor_x86.zip"
-	algorithm 'SHA-256'
-	checksum 'f5308aff8303daca082f82227d02b51ddedba4ab1d1420739ada0427ae5dbb41'
-}
-
-task verifyTorBinaryX86Pie(type: Verify, dependsOn: 'downloadTorBinaryX86Pie') {
-	src "$torBinaryDir/tor_x86_pie.zip"
-	algorithm 'SHA-256'
-	checksum '889a6c81ac73d05d35ed610ca5a913cee44d333e4ae1749c2a107f2f7dd8197b'
+def verifyBinary(name, chksum) {
+	return tasks.create([
+			name     : "verifyBinary${name}",
+			type     : Verify,
+			dependsOn: downloadBinary(name)]) {
+		src "${torBinaryDir}/${name}.zip"
+		algorithm 'SHA-256'
+		checksum chksum
+	}
 }
 
 project.afterEvaluate {
-	preBuild.dependsOn {
-		[
-				'verifyTorGeoIp',
-				'verifyTorBinaryArm',
-				'verifyTorBinaryArmPie',
-				'verifyTorBinaryX86',
-				'verifyTorBinaryX86Pie'
-		]
+	torBinaries.every { key, value ->
+		preBuild.dependsOn.add(verifyBinary(key, value))
 	}
 }

bramble-android/src/main/AndroidManifest.xml

@@ -11,8 +11,6 @@
 	<uses-permission android:name="android.permission.INTERNET"/>
 	<uses-permission android:name="android.permission.READ_LOGS"/>
 	<uses-permission android:name="android.permission.WAKE_LOCK"/>
-	<!-- Since API 23, this is needed to add contacts via Bluetooth -->
-	<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
 
 	<application
 		android:allowBackup="false"

bramble-android/src/main/java/org/briarproject/bramble/plugin/AndroidPluginModule.java

@@ -13,7 +13,8 @@ import org.briarproject.bramble.api.plugin.simplex.SimplexPluginFactory;
 import org.briarproject.bramble.api.reporting.DevReporter;
 import org.briarproject.bramble.api.system.AndroidExecutor;
 import org.briarproject.bramble.api.system.LocationUtils;
-import org.briarproject.bramble.plugin.droidtooth.DroidtoothPluginFactory;
+import org.briarproject.bramble.api.system.Scheduler;
+import org.briarproject.bramble.plugin.bluetooth.AndroidBluetoothPluginFactory;
 import org.briarproject.bramble.plugin.tcp.AndroidLanTcpPluginFactory;
 import org.briarproject.bramble.plugin.tor.TorPluginFactory;
 
@@ -22,6 +23,7 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.concurrent.Executor;
+import java.util.concurrent.ScheduledExecutorService;
 
 import javax.net.SocketFactory;
 
@@ -33,19 +35,21 @@ public class AndroidPluginModule {
 
 	@Provides
 	PluginConfig providePluginConfig(@IoExecutor Executor ioExecutor,
+			@Scheduler ScheduledExecutorService scheduler,
 			AndroidExecutor androidExecutor, SecureRandom random,
 			SocketFactory torSocketFactory, BackoffFactory backoffFactory,
 			Application app, LocationUtils locationUtils, DevReporter reporter,
 			EventBus eventBus) {
 		Context appContext = app.getApplicationContext();
-		DuplexPluginFactory bluetooth = new DroidtoothPluginFactory(ioExecutor,
-				androidExecutor, appContext, random, backoffFactory);
-		DuplexPluginFactory tor = new TorPluginFactory(ioExecutor, appContext,
-				locationUtils, reporter, eventBus, torSocketFactory,
-				backoffFactory);
+		DuplexPluginFactory bluetooth =
+				new AndroidBluetoothPluginFactory(ioExecutor, androidExecutor,
+						appContext, random, eventBus, backoffFactory);
+		DuplexPluginFactory tor = new TorPluginFactory(ioExecutor, scheduler,
+				appContext, locationUtils, reporter, eventBus,
+				torSocketFactory, backoffFactory);
 		DuplexPluginFactory lan = new AndroidLanTcpPluginFactory(ioExecutor,
 				backoffFactory, appContext);
-		final Collection<DuplexPluginFactory> duplex =
+		Collection<DuplexPluginFactory> duplex =
 				Arrays.asList(bluetooth, tor, lan);
 		@NotNullByDefault
 		PluginConfig pluginConfig = new PluginConfig() {

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

@@ -0,0 +1,206 @@
+package org.briarproject.bramble.plugin.bluetooth;
+
+import android.bluetooth.BluetoothAdapter;
+import android.bluetooth.BluetoothDevice;
+import android.bluetooth.BluetoothServerSocket;
+import android.bluetooth.BluetoothSocket;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.bramble.api.plugin.Backoff;
+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.util.AndroidUtils;
+
+import java.io.Closeable;
+import java.io.IOException;
+import java.security.SecureRandom;
+import java.util.UUID;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+
+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;
+import static android.bluetooth.BluetoothAdapter.EXTRA_STATE;
+import static android.bluetooth.BluetoothAdapter.SCAN_MODE_CONNECTABLE;
+import static android.bluetooth.BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE;
+import static android.bluetooth.BluetoothAdapter.SCAN_MODE_NONE;
+import static android.bluetooth.BluetoothAdapter.STATE_OFF;
+import static android.bluetooth.BluetoothAdapter.STATE_ON;
+import static java.util.logging.Level.WARNING;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+class AndroidBluetoothPlugin extends BluetoothPlugin<BluetoothServerSocket> {
+
+	private static final Logger LOG =
+			Logger.getLogger(AndroidBluetoothPlugin.class.getName());
+
+	private final AndroidExecutor androidExecutor;
+	private final Context appContext;
+
+	private volatile boolean wasEnabledByUs = false;
+	private volatile BluetoothStateReceiver receiver = null;
+
+	// Non-null if the plugin started successfully
+	private volatile BluetoothAdapter adapter = null;
+
+	AndroidBluetoothPlugin(Executor ioExecutor, AndroidExecutor androidExecutor,
+			Context appContext, SecureRandom secureRandom, Backoff backoff,
+			DuplexPluginCallback callback, int maxLatency) {
+		super(ioExecutor, secureRandom, backoff, callback, maxLatency);
+		this.androidExecutor = androidExecutor;
+		this.appContext = appContext;
+	}
+
+	@Override
+	public void start() throws PluginException {
+		super.start();
+		// Listen for changes to the Bluetooth state
+		IntentFilter filter = new IntentFilter();
+		filter.addAction(ACTION_STATE_CHANGED);
+		filter.addAction(ACTION_SCAN_MODE_CHANGED);
+		receiver = new BluetoothStateReceiver();
+		appContext.registerReceiver(receiver, filter);
+	}
+
+	@Override
+	public void stop() {
+		super.stop();
+		if (receiver != null) appContext.unregisterReceiver(receiver);
+	}
+
+	@Override
+	void initialiseAdapter() throws IOException {
+		// BluetoothAdapter.getDefaultAdapter() must be called on a thread
+		// with a message queue, so submit it to the AndroidExecutor
+		try {
+			adapter = androidExecutor.runOnBackgroundThread(
+					BluetoothAdapter::getDefaultAdapter).get();
+		} catch (InterruptedException | ExecutionException e) {
+			throw new IOException(e);
+		}
+		if (adapter == null)
+			throw new IOException("Bluetooth is not supported");
+	}
+
+	@Override
+	boolean isAdapterEnabled() {
+		return adapter != null && adapter.isEnabled();
+	}
+
+	@Override
+	void enableAdapter() {
+		if (adapter != null && !adapter.isEnabled()) {
+			if (adapter.enable()) {
+				LOG.info("Enabling Bluetooth");
+				wasEnabledByUs = true;
+			} else {
+				LOG.info("Could not enable Bluetooth");
+			}
+		}
+	}
+
+	@Override
+	void disableAdapterIfEnabledByUs() {
+		if (isAdapterEnabled() && wasEnabledByUs) {
+			if (adapter.disable()) LOG.info("Disabling Bluetooth");
+			else LOG.info("Could not disable Bluetooth");
+			wasEnabledByUs = false;
+		}
+	}
+
+	@Override
+	void setEnabledByUs() {
+		wasEnabledByUs = true;
+	}
+
+	@Override
+	@Nullable
+	String getBluetoothAddress() {
+		String address = AndroidUtils.getBluetoothAddress(appContext, adapter);
+		return address.isEmpty() ? null : address;
+	}
+
+	@Override
+	BluetoothServerSocket openServerSocket(String uuid) throws IOException {
+		return adapter.listenUsingInsecureRfcommWithServiceRecord(
+				"RFCOMM", UUID.fromString(uuid));
+	}
+
+	@Override
+	void tryToClose(@Nullable BluetoothServerSocket ss) {
+		try {
+			if (ss != null) ss.close();
+		} catch (IOException e) {
+			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+		}
+	}
+
+	@Override
+	DuplexTransportConnection acceptConnection(BluetoothServerSocket ss)
+			throws IOException {
+		return wrapSocket(ss.accept());
+	}
+
+	private DuplexTransportConnection wrapSocket(BluetoothSocket s) {
+		return new AndroidBluetoothTransportConnection(this, s);
+	}
+
+	@Override
+	boolean isValidAddress(String address) {
+		return BluetoothAdapter.checkBluetoothAddress(address);
+	}
+
+	@Override
+	DuplexTransportConnection connectTo(String address, String uuid)
+			throws IOException {
+		BluetoothDevice d = adapter.getRemoteDevice(address);
+		UUID u = UUID.fromString(uuid);
+		BluetoothSocket s = null;
+		try {
+			s = d.createInsecureRfcommSocketToServiceRecord(u);
+			s.connect();
+			return wrapSocket(s);
+		} catch (IOException e) {
+			tryToClose(s);
+			throw e;
+		}
+	}
+
+	private void tryToClose(@Nullable Closeable c) {
+		try {
+			if (c != null) c.close();
+		} catch (IOException e) {
+			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+		}
+	}
+
+	private class BluetoothStateReceiver extends BroadcastReceiver {
+
+		@Override
+		public void onReceive(Context ctx, Intent intent) {
+			int state = intent.getIntExtra(EXTRA_STATE, 0);
+			if (state == STATE_ON) onAdapterEnabled();
+			else if (state == STATE_OFF) onAdapterDisabled();
+			int scanMode = intent.getIntExtra(EXTRA_SCAN_MODE, 0);
+			if (scanMode == SCAN_MODE_NONE) {
+				LOG.info("Scan mode: None");
+			} else if (scanMode == SCAN_MODE_CONNECTABLE) {
+				LOG.info("Scan mode: Connectable");
+			} else if (scanMode == SCAN_MODE_CONNECTABLE_DISCOVERABLE) {
+				LOG.info("Scan mode: Discoverable");
+			}
+		}
+	}
+}

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

@@ -1,7 +1,8 @@
-package org.briarproject.bramble.plugin.droidtooth;
+package org.briarproject.bramble.plugin.bluetooth;
 
 import android.content.Context;
 
+import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Backoff;
 import org.briarproject.bramble.api.plugin.BackoffFactory;
@@ -20,7 +21,7 @@ import static org.briarproject.bramble.api.plugin.BluetoothConstants.ID;
 
 @Immutable
 @NotNullByDefault
-public class DroidtoothPluginFactory implements DuplexPluginFactory {
+public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 
 	private static final int MAX_LATENCY = 30 * 1000; // 30 seconds
 	private static final int MIN_POLLING_INTERVAL = 60 * 1000; // 1 minute
@@ -31,15 +32,18 @@ public class DroidtoothPluginFactory implements DuplexPluginFactory {
 	private final AndroidExecutor androidExecutor;
 	private final Context appContext;
 	private final SecureRandom secureRandom;
+	private final EventBus eventBus;
 	private final BackoffFactory backoffFactory;
 
-	public DroidtoothPluginFactory(Executor ioExecutor,
+	public AndroidBluetoothPluginFactory(Executor ioExecutor,
 			AndroidExecutor androidExecutor, Context appContext,
-			SecureRandom secureRandom, BackoffFactory backoffFactory) {
+			SecureRandom secureRandom, EventBus eventBus,
+			BackoffFactory backoffFactory) {
 		this.ioExecutor = ioExecutor;
 		this.androidExecutor = androidExecutor;
 		this.appContext = appContext;
 		this.secureRandom = secureRandom;
+		this.eventBus = eventBus;
 		this.backoffFactory = backoffFactory;
 	}
 
@@ -57,7 +61,10 @@ public class DroidtoothPluginFactory implements DuplexPluginFactory {
 	public DuplexPlugin createPlugin(DuplexPluginCallback callback) {
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		return new DroidtoothPlugin(ioExecutor, androidExecutor, appContext,
-				secureRandom, backoff, callback, MAX_LATENCY);
+		AndroidBluetoothPlugin plugin = new AndroidBluetoothPlugin(ioExecutor,
+				androidExecutor, appContext, secureRandom, backoff, callback,
+				MAX_LATENCY);
+		eventBus.addListener(plugin);
+		return plugin;
 	}
 }

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

@@ -1,4 +1,4 @@
-package org.briarproject.bramble.plugin.droidtooth;
+package org.briarproject.bramble.plugin.bluetooth;
 
 import android.bluetooth.BluetoothSocket;
 
@@ -11,11 +11,12 @@ import java.io.InputStream;
 import java.io.OutputStream;
 
 @NotNullByDefault
-class DroidtoothTransportConnection extends AbstractDuplexTransportConnection {
+class AndroidBluetoothTransportConnection
+		extends AbstractDuplexTransportConnection {
 
 	private final BluetoothSocket socket;
 
-	DroidtoothTransportConnection(Plugin plugin, BluetoothSocket socket) {
+	AndroidBluetoothTransportConnection(Plugin plugin, BluetoothSocket socket) {
 		super(plugin);
 		this.socket = socket;
 	}

bramble-android/src/main/java/org/briarproject/bramble/plugin/droidtooth/DroidtoothPlugin.java

@@ -1,682 +0,0 @@
-package org.briarproject.bramble.plugin.droidtooth;
-
-import android.bluetooth.BluetoothAdapter;
-import android.bluetooth.BluetoothDevice;
-import android.bluetooth.BluetoothServerSocket;
-import android.bluetooth.BluetoothSocket;
-import android.content.BroadcastReceiver;
-import android.content.Context;
-import android.content.Intent;
-import android.content.IntentFilter;
-
-import org.briarproject.bramble.api.FormatException;
-import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.crypto.PseudoRandom;
-import org.briarproject.bramble.api.data.BdfList;
-import org.briarproject.bramble.api.keyagreement.KeyAgreementConnection;
-import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
-import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
-import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
-import org.briarproject.bramble.api.plugin.Backoff;
-import org.briarproject.bramble.api.plugin.PluginException;
-import org.briarproject.bramble.api.plugin.TransportId;
-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.api.system.AndroidExecutor;
-import org.briarproject.bramble.util.AndroidUtils;
-import org.briarproject.bramble.util.StringUtils;
-
-import java.io.Closeable;
-import java.io.IOException;
-import java.io.InputStream;
-import java.security.SecureRandom;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.List;
-import java.util.Map;
-import java.util.Map.Entry;
-import java.util.UUID;
-import java.util.concurrent.Callable;
-import java.util.concurrent.CompletionService;
-import java.util.concurrent.CopyOnWriteArrayList;
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.ExecutionException;
-import java.util.concurrent.Executor;
-import java.util.concurrent.ExecutorCompletionService;
-import java.util.concurrent.Future;
-import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.logging.Logger;
-
-import javax.annotation.Nullable;
-
-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;
-import static android.bluetooth.BluetoothAdapter.EXTRA_STATE;
-import static android.bluetooth.BluetoothAdapter.SCAN_MODE_CONNECTABLE;
-import static android.bluetooth.BluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE;
-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.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.api.keyagreement.KeyAgreementConstants.TRANSPORT_ID_BLUETOOTH;
-import static org.briarproject.bramble.api.plugin.BluetoothConstants.ID;
-import static org.briarproject.bramble.api.plugin.BluetoothConstants.PREF_BT_ENABLE;
-import static org.briarproject.bramble.api.plugin.BluetoothConstants.PROP_ADDRESS;
-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.PrivacyUtils.scrubMacAddress;
-
-@MethodsNotNullByDefault
-@ParametersNotNullByDefault
-class DroidtoothPlugin implements DuplexPlugin {
-
-	private static final Logger LOG =
-			Logger.getLogger(DroidtoothPlugin.class.getName());
-	private static final String FOUND =
-			"android.bluetooth.device.action.FOUND";
-	private static final String DISCOVERY_FINISHED =
-			"android.bluetooth.adapter.action.DISCOVERY_FINISHED";
-
-	private final Executor ioExecutor;
-	private final AndroidExecutor androidExecutor;
-	private final Context appContext;
-	private final SecureRandom secureRandom;
-	private final Backoff backoff;
-	private final DuplexPluginCallback callback;
-	private final int maxLatency;
-	private final AtomicBoolean used = new AtomicBoolean(false);
-
-	private volatile boolean running = false;
-	private volatile boolean wasEnabledByUs = false;
-	private volatile BluetoothStateReceiver receiver = null;
-	private volatile BluetoothServerSocket socket = null;
-
-	// Non-null if the plugin started successfully
-	private volatile BluetoothAdapter adapter = null;
-
-	DroidtoothPlugin(Executor ioExecutor, AndroidExecutor androidExecutor,
-			Context appContext, SecureRandom secureRandom, Backoff backoff,
-			DuplexPluginCallback callback, int maxLatency) {
-		this.ioExecutor = ioExecutor;
-		this.androidExecutor = androidExecutor;
-		this.appContext = appContext;
-		this.secureRandom = secureRandom;
-		this.backoff = backoff;
-		this.callback = callback;
-		this.maxLatency = maxLatency;
-	}
-
-	@Override
-	public TransportId getId() {
-		return ID;
-	}
-
-	@Override
-	public int getMaxLatency() {
-		return maxLatency;
-	}
-
-	@Override
-	public int getMaxIdleTime() {
-		// Bluetooth detects dead connections so we don't need keepalives
-		return Integer.MAX_VALUE;
-	}
-
-	@Override
-	public void start() throws PluginException {
-		if (used.getAndSet(true)) throw new IllegalStateException();
-		// BluetoothAdapter.getDefaultAdapter() must be called on a thread
-		// with a message queue, so submit it to the AndroidExecutor
-		try {
-			adapter = androidExecutor.runOnBackgroundThread(
-					new Callable<BluetoothAdapter>() {
-						@Override
-						public BluetoothAdapter call() throws Exception {
-							return BluetoothAdapter.getDefaultAdapter();
-						}
-					}).get();
-		} catch (InterruptedException e) {
-			Thread.currentThread().interrupt();
-			LOG.warning("Interrupted while getting BluetoothAdapter");
-			throw new PluginException(e);
-		} catch (ExecutionException e) {
-			throw new PluginException(e);
-		}
-		if (adapter == null) {
-			LOG.info("Bluetooth is not supported");
-			throw new PluginException();
-		}
-		running = true;
-		// Listen for changes to the Bluetooth state
-		IntentFilter filter = new IntentFilter();
-		filter.addAction(ACTION_STATE_CHANGED);
-		filter.addAction(ACTION_SCAN_MODE_CHANGED);
-		receiver = new BluetoothStateReceiver();
-		appContext.registerReceiver(receiver, filter);
-		// If Bluetooth is enabled, bind a socket
-		if (adapter.isEnabled()) {
-			bind();
-		} else {
-			// Enable Bluetooth if settings allow
-			if (callback.getSettings().getBoolean(PREF_BT_ENABLE, false)) {
-				wasEnabledByUs = true;
-				if (adapter.enable()) LOG.info("Enabling Bluetooth");
-				else LOG.info("Could not enable Bluetooth");
-			} else {
-				LOG.info("Not enabling Bluetooth");
-			}
-		}
-	}
-
-	private void bind() {
-		ioExecutor.execute(new Runnable() {
-			@Override
-			public void run() {
-				if (!isRunning()) return;
-				String address = AndroidUtils.getBluetoothAddress(appContext,
-						adapter);
-				if (LOG.isLoggable(INFO))
-					LOG.info("Local address " + scrubMacAddress(address));
-				if (!StringUtils.isNullOrEmpty(address)) {
-					// Advertise the Bluetooth address to contacts
-					TransportProperties p = new TransportProperties();
-					p.put(PROP_ADDRESS, address);
-					callback.mergeLocalProperties(p);
-				}
-				// Bind a server socket to accept connections from contacts
-				BluetoothServerSocket ss;
-				try {
-					ss = adapter.listenUsingInsecureRfcommWithServiceRecord(
-							"RFCOMM", getUuid());
-				} catch (IOException e) {
-					if (LOG.isLoggable(WARNING))
-						LOG.log(WARNING, e.toString(), e);
-					return;
-				}
-				if (!isRunning()) {
-					tryToClose(ss);
-					return;
-				}
-				LOG.info("Socket bound");
-				socket = ss;
-				backoff.reset();
-				callback.transportEnabled();
-				acceptContactConnections();
-			}
-		});
-	}
-
-	private UUID getUuid() {
-		String uuid = callback.getLocalProperties().get(PROP_UUID);
-		if (uuid == null) {
-			byte[] random = new byte[UUID_BYTES];
-			secureRandom.nextBytes(random);
-			uuid = UUID.nameUUIDFromBytes(random).toString();
-			TransportProperties p = new TransportProperties();
-			p.put(PROP_UUID, uuid);
-			callback.mergeLocalProperties(p);
-		}
-		return UUID.fromString(uuid);
-	}
-
-	private void tryToClose(@Nullable BluetoothServerSocket ss) {
-		try {
-			if (ss != null) ss.close();
-		} catch (IOException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		} finally {
-			callback.transportDisabled();
-		}
-	}
-
-	private void acceptContactConnections() {
-		while (isRunning()) {
-			BluetoothSocket s;
-			try {
-				s = socket.accept();
-			} catch (IOException e) {
-				// This is expected when the socket is closed
-				if (LOG.isLoggable(INFO)) LOG.info(e.toString());
-				return;
-			}
-			if (LOG.isLoggable(INFO)) {
-				String address = s.getRemoteDevice().getAddress();
-				LOG.info("Connection from " + scrubMacAddress(address));
-			}
-			backoff.reset();
-			callback.incomingConnectionCreated(wrapSocket(s));
-		}
-	}
-
-	private DuplexTransportConnection wrapSocket(BluetoothSocket s) {
-		return new DroidtoothTransportConnection(this, s);
-	}
-
-	@Override
-	public void stop() {
-		running = false;
-		if (receiver != null) appContext.unregisterReceiver(receiver);
-		tryToClose(socket);
-		// Disable Bluetooth if we enabled it and it's still enabled
-		if (wasEnabledByUs && adapter.isEnabled()) {
-			if (adapter.disable()) LOG.info("Disabling Bluetooth");
-			else LOG.info("Could not disable Bluetooth");
-		}
-	}
-
-	@Override
-	public boolean isRunning() {
-		return running && adapter != null && adapter.isEnabled();
-	}
-
-	@Override
-	public boolean shouldPoll() {
-		return true;
-	}
-
-	@Override
-	public int getPollingInterval() {
-		return backoff.getPollingInterval();
-	}
-
-	@Override
-	public void poll(Collection<ContactId> connected) {
-		if (!isRunning()) return;
-		backoff.increment();
-		// Try to connect to known devices in parallel
-		Map<ContactId, TransportProperties> remote =
-				callback.getRemoteProperties();
-		for (Entry<ContactId, TransportProperties> e : remote.entrySet()) {
-			final ContactId c = e.getKey();
-			if (connected.contains(c)) continue;
-			final String address = e.getValue().get(PROP_ADDRESS);
-			if (StringUtils.isNullOrEmpty(address)) continue;
-			final String uuid = e.getValue().get(PROP_UUID);
-			if (StringUtils.isNullOrEmpty(uuid)) continue;
-			ioExecutor.execute(new Runnable() {
-				@Override
-				public void run() {
-					if (!running) return;
-					BluetoothSocket s = connect(address, uuid);
-					if (s != null) {
-						backoff.reset();
-						callback.outgoingConnectionCreated(c, wrapSocket(s));
-					}
-				}
-			});
-		}
-	}
-
-	@Nullable
-	private BluetoothSocket connect(String address, String uuid) {
-		// Validate the address
-		if (!BluetoothAdapter.checkBluetoothAddress(address)) {
-			if (LOG.isLoggable(WARNING))
-				// not scrubbing here to be able to figure out the problem
-				LOG.warning("Invalid address " + address);
-			return null;
-		}
-		// Validate the UUID
-		UUID u;
-		try {
-			u = UUID.fromString(uuid);
-		} catch (IllegalArgumentException e) {
-			if (LOG.isLoggable(WARNING)) LOG.warning("Invalid UUID " + uuid);
-			return null;
-		}
-		// Try to connect
-		BluetoothDevice d = adapter.getRemoteDevice(address);
-		BluetoothSocket s = null;
-		try {
-			s = d.createInsecureRfcommSocketToServiceRecord(u);
-			if (LOG.isLoggable(INFO))
-				LOG.info("Connecting to " + scrubMacAddress(address));
-			s.connect();
-			if (LOG.isLoggable(INFO))
-				LOG.info("Connected to " + scrubMacAddress(address));
-			return s;
-		} catch (IOException e) {
-			if (LOG.isLoggable(INFO)) {
-				LOG.info("Failed to connect to " + scrubMacAddress(address)
-						+ ": " + e);
-			}
-			tryToClose(s);
-			return null;
-		}
-	}
-
-	private void tryToClose(@Nullable Closeable c) {
-		try {
-			if (c != null) c.close();
-		} catch (IOException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		}
-	}
-
-	@Override
-	public DuplexTransportConnection createConnection(ContactId c) {
-		if (!isRunning()) return null;
-		TransportProperties p = callback.getRemoteProperties().get(c);
-		if (p == null) return null;
-		String address = p.get(PROP_ADDRESS);
-		if (StringUtils.isNullOrEmpty(address)) return null;
-		String uuid = p.get(PROP_UUID);
-		if (StringUtils.isNullOrEmpty(uuid)) return null;
-		BluetoothSocket s = connect(address, uuid);
-		if (s == null) return null;
-		return new DroidtoothTransportConnection(this, s);
-	}
-
-	@Override
-	public boolean supportsInvitations() {
-		return true;
-	}
-
-	@Override
-	public DuplexTransportConnection createInvitationConnection(PseudoRandom r,
-			long timeout, boolean alice) {
-		if (!isRunning()) return null;
-		// Use the invitation codes to generate the UUID
-		byte[] b = r.nextBytes(UUID_BYTES);
-		UUID uuid = UUID.nameUUIDFromBytes(b);
-		if (LOG.isLoggable(INFO)) LOG.info("Invitation UUID " + uuid);
-		// Bind a server socket for receiving invitation connections
-		BluetoothServerSocket ss;
-		try {
-			ss = adapter.listenUsingInsecureRfcommWithServiceRecord(
-					"RFCOMM", uuid);
-		} catch (IOException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			return null;
-		}
-		// Create the background tasks
-		CompletionService<BluetoothSocket> complete =
-				new ExecutorCompletionService<>(ioExecutor);
-		List<Future<BluetoothSocket>> futures = new ArrayList<>();
-		if (alice) {
-			// Return the first connected socket
-			futures.add(complete.submit(new ListeningTask(ss)));
-			futures.add(complete.submit(new DiscoveryTask(uuid.toString())));
-		} else {
-			// Return the first socket with readable data
-			futures.add(complete.submit(new ReadableTask(
-					new ListeningTask(ss))));
-			futures.add(complete.submit(new ReadableTask(
-					new DiscoveryTask(uuid.toString()))));
-		}
-		BluetoothSocket chosen = null;
-		try {
-			Future<BluetoothSocket> f = complete.poll(timeout, MILLISECONDS);
-			if (f == null) return null; // No task completed within the timeout
-			chosen = f.get();
-			return new DroidtoothTransportConnection(this, chosen);
-		} catch (InterruptedException e) {
-			LOG.info("Interrupted while exchanging invitations");
-			Thread.currentThread().interrupt();
-			return null;
-		} catch (ExecutionException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			return null;
-		} finally {
-			// Closing the socket will terminate the listener task
-			tryToClose(ss);
-			closeSockets(futures, chosen);
-		}
-	}
-
-	private void closeSockets(final List<Future<BluetoothSocket>> futures,
-			@Nullable final BluetoothSocket chosen) {
-		ioExecutor.execute(new Runnable() {
-			@Override
-			public void run() {
-				for (Future<BluetoothSocket> f : futures) {
-					try {
-						if (f.cancel(true)) {
-							LOG.info("Cancelled task");
-						} else {
-							BluetoothSocket s = f.get();
-							if (s != null && s != chosen) {
-								LOG.info("Closing unwanted socket");
-								s.close();
-							}
-						}
-					} catch (InterruptedException e) {
-						LOG.info("Interrupted while closing sockets");
-						return;
-					} catch (ExecutionException | IOException e) {
-						if (LOG.isLoggable(INFO)) LOG.info(e.toString());
-					}
-				}
-			}
-		});
-	}
-
-	@Override
-	public boolean supportsKeyAgreement() {
-		return true;
-	}
-
-	@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 = AndroidUtils.getBluetoothAddress(appContext, adapter);
-		if (address.isEmpty()) return null;
-		// No truncation necessary because COMMIT_LENGTH = 16
-		UUID uuid = UUID.nameUUIDFromBytes(commitment);
-		if (LOG.isLoggable(INFO)) LOG.info("Key agreement UUID " + uuid);
-		// Bind a server socket for receiving invitation connections
-		BluetoothServerSocket ss;
-		try {
-			ss = adapter.listenUsingInsecureRfcommWithServiceRecord(
-					"RFCOMM", uuid);
-		} catch (IOException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			return null;
-		}
-		BdfList descriptor = new BdfList();
-		descriptor.add(TRANSPORT_ID_BLUETOOTH);
-		descriptor.add(StringUtils.macToBytes(address));
-		return new BluetoothKeyAgreementListener(descriptor, ss);
-	}
-
-	@Override
-	public DuplexTransportConnection createKeyAgreementConnection(
-			byte[] commitment, BdfList descriptor, long timeout) {
-		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
-		UUID uuid = UUID.nameUUIDFromBytes(commitment);
-		if (LOG.isLoggable(INFO))
-			LOG.info("Connecting to key agreement UUID " + uuid);
-		BluetoothSocket s = connect(address, uuid.toString());
-		if (s == null) return null;
-		return new DroidtoothTransportConnection(this, s);
-	}
-
-	private String parseAddress(BdfList descriptor) throws FormatException {
-		byte[] mac = descriptor.getRaw(1);
-		if (mac.length != 6) throw new FormatException();
-		return StringUtils.macToString(mac);
-	}
-
-	private class BluetoothStateReceiver extends BroadcastReceiver {
-
-		@Override
-		public void onReceive(Context ctx, Intent intent) {
-			int state = intent.getIntExtra(EXTRA_STATE, 0);
-			if (state == STATE_ON) {
-				LOG.info("Bluetooth enabled");
-				bind();
-			} else if (state == STATE_OFF) {
-				LOG.info("Bluetooth disabled");
-				tryToClose(socket);
-			}
-			int scanMode = intent.getIntExtra(EXTRA_SCAN_MODE, 0);
-			if (scanMode == SCAN_MODE_NONE) {
-				LOG.info("Scan mode: None");
-			} else if (scanMode == SCAN_MODE_CONNECTABLE) {
-				LOG.info("Scan mode: Connectable");
-			} else if (scanMode == SCAN_MODE_CONNECTABLE_DISCOVERABLE) {
-				LOG.info("Scan mode: Discoverable");
-			}
-		}
-	}
-
-	private class DiscoveryTask implements Callable<BluetoothSocket> {
-
-		private final String uuid;
-
-		private DiscoveryTask(String uuid) {
-			this.uuid = uuid;
-		}
-
-		@Override
-		public BluetoothSocket call() throws Exception {
-			// Repeat discovery until we connect or get interrupted
-			while (true) {
-				// Discover nearby devices
-				LOG.info("Discovering nearby devices");
-				List<String> addresses = discoverDevices();
-				if (addresses.isEmpty()) {
-					LOG.info("No devices discovered");
-					continue;
-				}
-				// Connect to any device with the right UUID
-				for (String address : addresses) {
-					BluetoothSocket s = connect(address, uuid);
-					if (s != null) {
-						LOG.info("Outgoing connection");
-						return s;
-					}
-				}
-			}
-		}
-
-		private List<String> discoverDevices() throws InterruptedException {
-			IntentFilter filter = new IntentFilter();
-			filter.addAction(FOUND);
-			filter.addAction(DISCOVERY_FINISHED);
-			DiscoveryReceiver disco = new DiscoveryReceiver();
-			appContext.registerReceiver(disco, filter);
-			LOG.info("Starting discovery");
-			adapter.startDiscovery();
-			return disco.waitForAddresses();
-		}
-	}
-
-	private static class DiscoveryReceiver extends BroadcastReceiver {
-
-		private final CountDownLatch finished = new CountDownLatch(1);
-		private final List<String> addresses = new CopyOnWriteArrayList<>();
-
-		@Override
-		public void onReceive(Context ctx, Intent intent) {
-			String action = intent.getAction();
-			if (action.equals(DISCOVERY_FINISHED)) {
-				LOG.info("Discovery finished");
-				ctx.unregisterReceiver(this);
-				finished.countDown();
-			} else if (action.equals(FOUND)) {
-				BluetoothDevice d = intent.getParcelableExtra(EXTRA_DEVICE);
-				if (LOG.isLoggable(INFO)) {
-					LOG.info("Discovered device: " +
-							scrubMacAddress(d.getAddress()));
-				}
-				addresses.add(d.getAddress());
-			}
-		}
-
-		private List<String> waitForAddresses() throws InterruptedException {
-			finished.await();
-			List<String> shuffled = new ArrayList<>(addresses);
-			Collections.shuffle(shuffled);
-			return shuffled;
-		}
-	}
-
-	private static class ListeningTask implements Callable<BluetoothSocket> {
-
-		private final BluetoothServerSocket serverSocket;
-
-		private ListeningTask(BluetoothServerSocket serverSocket) {
-			this.serverSocket = serverSocket;
-		}
-
-		@Override
-		public BluetoothSocket call() throws IOException {
-			BluetoothSocket s = serverSocket.accept();
-			LOG.info("Incoming connection");
-			return s;
-		}
-	}
-
-	private static class ReadableTask implements Callable<BluetoothSocket> {
-
-		private final Callable<BluetoothSocket> connectionTask;
-
-		private ReadableTask(Callable<BluetoothSocket> connectionTask) {
-			this.connectionTask = connectionTask;
-		}
-
-		@Override
-		public BluetoothSocket call() throws Exception {
-			BluetoothSocket s = connectionTask.call();
-			InputStream in = s.getInputStream();
-			while (in.available() == 0) {
-				LOG.info("Waiting for data");
-				Thread.sleep(1000);
-			}
-			LOG.info("Data available");
-			return s;
-		}
-	}
-
-	private class BluetoothKeyAgreementListener extends KeyAgreementListener {
-
-		private final BluetoothServerSocket ss;
-
-		private BluetoothKeyAgreementListener(BdfList descriptor,
-				BluetoothServerSocket ss) {
-			super(descriptor);
-			this.ss = ss;
-		}
-
-		@Override
-		public Callable<KeyAgreementConnection> listen() {
-			return new Callable<KeyAgreementConnection>() {
-				@Override
-				public KeyAgreementConnection call() throws IOException {
-					BluetoothSocket s = ss.accept();
-					if (LOG.isLoggable(INFO))
-						LOG.info(ID.getString() + ": Incoming connection");
-					return new KeyAgreementConnection(
-							new DroidtoothTransportConnection(
-									DroidtoothPlugin.this, s), ID);
-				}
-			};
-		}
-
-		@Override
-		public void close() {
-			try {
-				ss.close();
-			} catch (IOException e) {
-				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			}
-		}
-	}
-}

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

@@ -17,7 +17,6 @@ import net.freehaven.tor.control.EventHandler;
 import net.freehaven.tor.control.TorControlConnection;
 
 import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.crypto.PseudoRandom;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.event.Event;
 import org.briarproject.bramble.api.event.EventListener;
@@ -56,10 +55,16 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Map;
+import java.util.Map.Entry;
 import java.util.Scanner;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.Executor;
+import java.util.concurrent.Future;
+import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
 import java.util.logging.Logger;
 import java.util.regex.Pattern;
 import java.util.zip.ZipInputStream;
@@ -70,10 +75,15 @@ import javax.net.SocketFactory;
 import static android.content.Context.CONNECTIVITY_SERVICE;
 import static android.content.Context.MODE_PRIVATE;
 import static android.content.Context.POWER_SERVICE;
+import static android.content.Intent.ACTION_SCREEN_OFF;
+import static android.content.Intent.ACTION_SCREEN_ON;
 import static android.net.ConnectivityManager.CONNECTIVITY_ACTION;
 import static android.net.ConnectivityManager.TYPE_WIFI;
+import static android.os.Build.VERSION.SDK_INT;
+import static android.os.PowerManager.ACTION_DEVICE_IDLE_MODE_CHANGED;
 import static android.os.PowerManager.PARTIAL_WAKE_LOCK;
 import static java.util.concurrent.TimeUnit.MILLISECONDS;
+import static java.util.concurrent.TimeUnit.MINUTES;
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static net.freehaven.tor.control.TorControlCommands.HS_ADDRESS;
@@ -85,13 +95,13 @@ import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK_
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK_NEVER;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_NETWORK_WIFI;
 import static org.briarproject.bramble.api.plugin.TorConstants.PREF_TOR_PORT;
+import static org.briarproject.bramble.api.plugin.TorConstants.PROP_ONION;
 import static org.briarproject.bramble.util.PrivacyUtils.scrubOnion;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
 class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
-	private static final String PROP_ONION = "onion";
 	private static final String[] EVENTS = {
 			"CIRC", "ORCONN", "HS_DESC", "NOTICE", "WARN", "ERR"
 	};
@@ -102,6 +112,7 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 			Logger.getLogger(TorPlugin.class.getName());
 
 	private final Executor ioExecutor;
+	private final ScheduledExecutorService scheduler;
 	private final Context appContext;
 	private final LocationUtils locationUtils;
 	private final DevReporter reporter;
@@ -114,6 +125,9 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private final File torDirectory, torFile, geoIpFile, configFile;
 	private final File doneFile, cookieFile;
 	private final PowerManager.WakeLock wakeLock;
+	private final Lock connectionStatusLock;
+	private final AtomicReference<Future<?>> connectivityCheck =
+			new AtomicReference<>();
 	private final AtomicBoolean used = new AtomicBoolean(false);
 
 	private volatile boolean running = false;
@@ -122,12 +136,13 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	private volatile TorControlConnection controlConnection = null;
 	private volatile BroadcastReceiver networkStateReceiver = null;
 
-	TorPlugin(Executor ioExecutor, Context appContext,
-			LocationUtils locationUtils, DevReporter reporter,
-			SocketFactory torSocketFactory, Backoff backoff,
-			DuplexPluginCallback callback, String architecture, int maxLatency,
-			int maxIdleTime) {
+	TorPlugin(Executor ioExecutor, ScheduledExecutorService scheduler,
+			Context appContext, LocationUtils locationUtils,
+			DevReporter reporter, SocketFactory torSocketFactory,
+			Backoff backoff, DuplexPluginCallback callback,
+			String architecture, int maxLatency, int maxIdleTime) {
 		this.ioExecutor = ioExecutor;
+		this.scheduler = scheduler;
 		this.appContext = appContext;
 		this.locationUtils = locationUtils;
 		this.reporter = reporter;
@@ -149,8 +164,10 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		cookieFile = new File(torDirectory, ".tor/control_auth_cookie");
 		Object o = appContext.getSystemService(POWER_SERVICE);
 		PowerManager pm = (PowerManager) o;
-		wakeLock = pm.newWakeLock(PARTIAL_WAKE_LOCK, "TorPlugin");
+		// This tag will prevent Huawei's powermanager from killing us.
+		wakeLock = pm.newWakeLock(PARTIAL_WAKE_LOCK, "LocationManagerService");
 		wakeLock.setReferenceCounted(false);
+		connectionStatusLock = new ReentrantLock();
 	}
 
 	@Override
@@ -203,11 +220,11 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		if (LOG.isLoggable(INFO)) {
 			Scanner stdout = new Scanner(torProcess.getInputStream());
 			Scanner stderr = new Scanner(torProcess.getErrorStream());
-			while (stdout.hasNextLine() || stderr.hasNextLine()){
-				if(stdout.hasNextLine()) {
+			while (stdout.hasNextLine() || stderr.hasNextLine()) {
+				if (stdout.hasNextLine()) {
 					LOG.info(stdout.nextLine());
 				}
-				if(stderr.hasNextLine()){
+				if (stderr.hasNextLine()) {
 					LOG.info(stderr.nextLine());
 				}
 			}
@@ -256,7 +273,11 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		}
 		// Register to receive network status events
 		networkStateReceiver = new NetworkStateReceiver();
-		IntentFilter filter = new IntentFilter(CONNECTIVITY_ACTION);
+		IntentFilter filter = new IntentFilter();
+		filter.addAction(CONNECTIVITY_ACTION);
+		filter.addAction(ACTION_SCREEN_ON);
+		filter.addAction(ACTION_SCREEN_OFF);
+		if (SDK_INT >= 23) filter.addAction(ACTION_DEVICE_IDLE_MODE_CHANGED);
 		appContext.registerReceiver(networkStateReceiver, filter);
 		// Bind a server socket to receive incoming hidden service connections
 		bind();
@@ -369,57 +390,45 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	private void sendDevReports() {
-		ioExecutor.execute(new Runnable() {
-			@Override
-			public void run() {
-				// TODO: Trigger this with a TransportEnabledEvent
-				File reportDir = AndroidUtils.getReportDir(appContext);
-				reporter.sendReports(reportDir);
-			}
+		ioExecutor.execute(() -> {
+			// TODO: Trigger this with a TransportEnabledEvent
+			File reportDir = AndroidUtils.getReportDir(appContext);
+			reporter.sendReports(reportDir);
 		});
 	}
 
 	private void bind() {
-		ioExecutor.execute(new Runnable() {
-			@Override
-			public void run() {
-				// If there's already a port number stored in config, reuse it
-				String portString = callback.getSettings().get(PREF_TOR_PORT);
-				int port;
-				if (StringUtils.isNullOrEmpty(portString)) port = 0;
-				else port = Integer.parseInt(portString);
-				// Bind a server socket to receive connections from Tor
-				ServerSocket ss = null;
-				try {
-					ss = new ServerSocket();
-					ss.bind(new InetSocketAddress("127.0.0.1", port));
-				} catch (IOException e) {
-					if (LOG.isLoggable(WARNING))
-						LOG.log(WARNING, e.toString(), e);
-					tryToClose(ss);
-					return;
-				}
-				if (!running) {
-					tryToClose(ss);
-					return;
-				}
-				socket = ss;
-				// Store the port number
-				final String localPort = String.valueOf(ss.getLocalPort());
-				Settings s = new Settings();
-				s.put(PREF_TOR_PORT, localPort);
-				callback.mergeSettings(s);
-				// Create a hidden service if necessary
-				ioExecutor.execute(new Runnable() {
-					@Override
-					public void run() {
-						publishHiddenService(localPort);
-					}
-				});
-				backoff.reset();
-				// Accept incoming hidden service connections from Tor
-				acceptContactConnections(ss);
+		ioExecutor.execute(() -> {
+			// If there's already a port number stored in config, reuse it
+			String portString = callback.getSettings().get(PREF_TOR_PORT);
+			int port;
+			if (StringUtils.isNullOrEmpty(portString)) port = 0;
+			else port = Integer.parseInt(portString);
+			// Bind a server socket to receive connections from Tor
+			ServerSocket ss = null;
+			try {
+				ss = new ServerSocket();
+				ss.bind(new InetSocketAddress("127.0.0.1", port));
+			} catch (IOException e) {
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+				tryToClose(ss);
+				return;
 			}
+			if (!running) {
+				tryToClose(ss);
+				return;
+			}
+			socket = ss;
+			// Store the port number
+			String localPort = String.valueOf(ss.getLocalPort());
+			Settings s = new Settings();
+			s.put(PREF_TOR_PORT, localPort);
+			callback.mergeSettings(s);
+			// Create a hidden service if necessary
+			ioExecutor.execute(() -> publishHiddenService(localPort));
+			backoff.reset();
+			// Accept incoming hidden service connections from Tor
+			acceptContactConnections(ss);
 		});
 	}
 
@@ -539,20 +548,21 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	public void poll(Collection<ContactId> connected) {
 		if (!isRunning()) return;
 		backoff.increment();
-		// TODO: Pass properties to connectAndCallBack()
-		for (ContactId c : callback.getRemoteProperties().keySet())
-			if (!connected.contains(c)) connectAndCallBack(c);
+		Map<ContactId, TransportProperties> remote =
+				callback.getRemoteProperties();
+		for (Entry<ContactId, TransportProperties> e : remote.entrySet()) {
+			ContactId c = e.getKey();
+			if (!connected.contains(c)) connectAndCallBack(c, e.getValue());
+		}
 	}
 
-	private void connectAndCallBack(final ContactId c) {
-		ioExecutor.execute(new Runnable() {
-			@Override
-			public void run() {
-				DuplexTransportConnection d = createConnection(c);
-				if (d != null) {
-					backoff.reset();
-					callback.outgoingConnectionCreated(c, d);
-				}
+	private void connectAndCallBack(ContactId c, TransportProperties p) {
+		ioExecutor.execute(() -> {
+			if (!isRunning()) return;
+			DuplexTransportConnection d = createConnection(p);
+			if (d != null) {
+				backoff.reset();
+				callback.outgoingConnectionCreated(c, d);
 			}
 		});
 	}
@@ -560,8 +570,11 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	@Override
 	public DuplexTransportConnection createConnection(ContactId c) {
 		if (!isRunning()) return null;
-		TransportProperties p = callback.getRemoteProperties().get(c);
-		if (p == null) return null;
+		return createConnection(callback.getRemoteProperties(c));
+	}
+
+	@Nullable
+	private DuplexTransportConnection createConnection(TransportProperties p) {
 		String onion = p.get(PROP_ONION);
 		if (StringUtils.isNullOrEmpty(onion)) return null;
 		if (!ONION.matcher(onion).matches()) {
@@ -589,17 +602,6 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		}
 	}
 
-	@Override
-	public boolean supportsInvitations() {
-		return false;
-	}
-
-	@Override
-	public DuplexTransportConnection createInvitationConnection(PseudoRandom r,
-			long timeout, boolean alice) {
-		throw new UnsupportedOperationException();
-	}
-
 	@Override
 	public boolean supportsKeyAgreement() {
 		return false;
@@ -612,7 +614,7 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 
 	@Override
 	public DuplexTransportConnection createKeyAgreementConnection(
-			byte[] commitment, BdfList descriptor, long timeout) {
+			byte[] commitment, BdfList descriptor) {
 		throw new UnsupportedOperationException();
 	}
 
@@ -636,6 +638,8 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	@Override
 	public void orConnStatus(String status, String orName) {
 		if (LOG.isLoggable(INFO)) LOG.info("OR connection " + status);
+		if (status.equals("CLOSED") || status.equals("FAILED"))
+			updateConnectionStatus(); // Check whether we've lost connectivity
 	}
 
 	@Override
@@ -675,7 +679,7 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 		}
 
 		@Override
-		public void onEvent(int event, String path) {
+		public void onEvent(int event, @Nullable String path) {
 			stopWatching();
 			latch.countDown();
 		}
@@ -693,60 +697,75 @@ class TorPlugin implements DuplexPlugin, EventHandler, EventListener {
 	}
 
 	private void updateConnectionStatus() {
-		ioExecutor.execute(new Runnable() {
-			@Override
-			public void run() {
-				if (!running) return;
-
-				Object o = appContext.getSystemService(CONNECTIVITY_SERVICE);
-				ConnectivityManager cm = (ConnectivityManager) o;
-				NetworkInfo net = cm.getActiveNetworkInfo();
-				boolean online = net != null && net.isConnected();
-				boolean wifi = online && net.getType() == TYPE_WIFI;
-				String country = locationUtils.getCurrentCountry();
-				boolean blocked = TorNetworkMetadata.isTorProbablyBlocked(
-						country);
-				Settings s = callback.getSettings();
-				int network = s.getInt(PREF_TOR_NETWORK,
-						PREF_TOR_NETWORK_ALWAYS);
-
-				if (LOG.isLoggable(INFO)) {
-					LOG.info("Online: " + online + ", wifi: " + wifi);
-					if ("".equals(country)) LOG.info("Country code unknown");
-					else LOG.info("Country code: " + country);
-				}
-
-				try {
-					if (!online) {
-						LOG.info("Disabling network, device is offline");
-						enableNetwork(false);
-					} else if (blocked) {
-						LOG.info("Disabling network, country is blocked");
-						enableNetwork(false);
-					} else if (network == PREF_TOR_NETWORK_NEVER
-							|| (network == PREF_TOR_NETWORK_WIFI && !wifi)) {
-						LOG.info("Disabling network due to data setting");
-						enableNetwork(false);
-					} else {
-						LOG.info("Enabling network");
-						enableNetwork(true);
-					}
-				} catch (IOException e) {
-					if (LOG.isLoggable(WARNING))
-						LOG.log(WARNING, e.toString(), e);
-				}
+		ioExecutor.execute(() -> {
+			if (!running) return;
+			try {
+				connectionStatusLock.lock();
+				updateConnectionStatusLocked();
+			} finally {
+				connectionStatusLock.unlock();
 			}
 		});
 	}
 
+	// Locking: connectionStatusLock
+	private void updateConnectionStatusLocked() {
+		Object o = appContext.getSystemService(CONNECTIVITY_SERVICE);
+		ConnectivityManager cm = (ConnectivityManager) o;
+		NetworkInfo net = cm.getActiveNetworkInfo();
+		boolean online = net != null && net.isConnected();
+		boolean wifi = online && net.getType() == TYPE_WIFI;
+		String country = locationUtils.getCurrentCountry();
+		boolean blocked = TorNetworkMetadata.isTorProbablyBlocked(
+				country);
+		Settings s = callback.getSettings();
+		int network = s.getInt(PREF_TOR_NETWORK, PREF_TOR_NETWORK_ALWAYS);
+
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Online: " + online + ", wifi: " + wifi);
+			if ("".equals(country)) LOG.info("Country code unknown");
+			else LOG.info("Country code: " + country);
+		}
+
+		try {
+			if (!online) {
+				LOG.info("Disabling network, device is offline");
+				enableNetwork(false);
+			} else if (blocked) {
+				LOG.info("Disabling network, country is blocked");
+				enableNetwork(false);
+			} else if (network == PREF_TOR_NETWORK_NEVER
+					|| (network == PREF_TOR_NETWORK_WIFI && !wifi)) {
+				LOG.info("Disabling network due to data setting");
+				enableNetwork(false);
+			} else {
+				LOG.info("Enabling network");
+				enableNetwork(true);
+			}
+		} catch (IOException e) {
+			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+		}
+	}
+
+	private void scheduleConnectionStatusUpdate() {
+		Future<?> newConnectivityCheck =
+				scheduler.schedule(this::updateConnectionStatus, 1, MINUTES);
+		Future<?> oldConnectivityCheck =
+				connectivityCheck.getAndSet(newConnectivityCheck);
+		if (oldConnectivityCheck != null) oldConnectivityCheck.cancel(false);
+	}
+
 	private class NetworkStateReceiver extends BroadcastReceiver {
 
 		@Override
 		public void onReceive(Context ctx, Intent i) {
 			if (!running) return;
-			if (CONNECTIVITY_ACTION.equals(i.getAction())) {
-				LOG.info("Detected connectivity change");
-				updateConnectionStatus();
+			String action = i.getAction();
+			if (LOG.isLoggable(INFO)) LOG.info("Received broadcast " + action);
+			updateConnectionStatus();
+			if (ACTION_SCREEN_ON.equals(action)
+					|| ACTION_SCREEN_OFF.equals(action)) {
+				scheduleConnectionStatusUpdate();
 			}
 		}
 	}

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

@@ -17,6 +17,7 @@ import org.briarproject.bramble.api.system.LocationUtils;
 import org.briarproject.bramble.util.AndroidUtils;
 
 import java.util.concurrent.Executor;
+import java.util.concurrent.ScheduledExecutorService;
 import java.util.logging.Logger;
 
 import javax.annotation.concurrent.Immutable;
@@ -36,6 +37,7 @@ public class TorPluginFactory implements DuplexPluginFactory {
 	private static final double BACKOFF_BASE = 1.2;
 
 	private final Executor ioExecutor;
+	private final ScheduledExecutorService scheduler;
 	private final Context appContext;
 	private final LocationUtils locationUtils;
 	private final DevReporter reporter;
@@ -43,11 +45,13 @@ public class TorPluginFactory implements DuplexPluginFactory {
 	private final SocketFactory torSocketFactory;
 	private final BackoffFactory backoffFactory;
 
-	public TorPluginFactory(Executor ioExecutor, Context appContext,
+	public TorPluginFactory(Executor ioExecutor,
+			ScheduledExecutorService scheduler, Context appContext,
 			LocationUtils locationUtils, DevReporter reporter,
 			EventBus eventBus, SocketFactory torSocketFactory,
 			BackoffFactory backoffFactory) {
 		this.ioExecutor = ioExecutor;
+		this.scheduler = scheduler;
 		this.appContext = appContext;
 		this.locationUtils = locationUtils;
 		this.reporter = reporter;
@@ -89,9 +93,9 @@ public class TorPluginFactory implements DuplexPluginFactory {
 
 		Backoff backoff = backoffFactory.createBackoff(MIN_POLLING_INTERVAL,
 				MAX_POLLING_INTERVAL, BACKOFF_BASE);
-		TorPlugin plugin = new TorPlugin(ioExecutor, appContext, locationUtils,
-				reporter, torSocketFactory, backoff, callback, architecture,
-				MAX_LATENCY, MAX_IDLE_TIME);
+		TorPlugin plugin = new TorPlugin(ioExecutor, scheduler, appContext,
+				locationUtils, reporter, torSocketFactory, backoff, callback,
+				architecture, MAX_LATENCY, MAX_IDLE_TIME);
 		eventBus.addListener(plugin);
 		return plugin;
 	}

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

@@ -3,6 +3,7 @@ package org.briarproject.bramble.plugin.tor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.Plugin;
 import org.briarproject.bramble.api.plugin.duplex.AbstractDuplexTransportConnection;
+import org.briarproject.bramble.util.IoUtils;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -21,12 +22,12 @@ class TorTransportConnection extends AbstractDuplexTransportConnection {
 
 	@Override
 	protected InputStream getInputStream() throws IOException {
-		return socket.getInputStream();
+		return IoUtils.getInputStream(socket);
 	}
 
 	@Override
 	protected OutputStream getOutputStream() throws IOException {
-		return socket.getOutputStream();
+		return IoUtils.getOutputStream(socket);
 	}
 
 	@Override

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

@@ -27,14 +27,11 @@ class AndroidExecutorImpl implements AndroidExecutor {
 	@Inject
 	AndroidExecutorImpl(Application app) {
 		uiHandler = new Handler(app.getApplicationContext().getMainLooper());
-		loop = new Runnable() {
-			@Override
-			public void run() {
-				Looper.prepare();
-				backgroundHandler = new Handler();
-				startLatch.countDown();
-				Looper.loop();
-			}
+		loop = () -> {
+			Looper.prepare();
+			backgroundHandler = new Handler();
+			startLatch.countDown();
+			Looper.loop();
 		};
 	}
 

bramble-api/build.gradle

@@ -1,30 +1,39 @@
-apply plugin: 'java'
-sourceCompatibility = 1.6
-targetCompatibility = 1.6
+apply plugin: 'java-library'
+sourceCompatibility = 1.8
+targetCompatibility = 1.8
 
 apply plugin: 'witness'
 
 dependencies {
-	compile "com.google.dagger:dagger:2.0.2"
-	compile 'com.google.dagger:dagger-compiler:2.0.2'
-	compile 'com.google.code.findbugs:jsr305:3.0.2'
+	implementation "com.google.dagger:dagger:2.0.2"
+	implementation 'com.google.code.findbugs:jsr305:3.0.2'
 
-	testCompile 'junit:junit:4.12'
-	testCompile "org.jmock:jmock:2.8.2"
-	testCompile "org.jmock:jmock-junit4:2.8.2"
-	testCompile "org.jmock:jmock-legacy:2.8.2"
-	testCompile "org.hamcrest:hamcrest-library:1.3"
-	testCompile "org.hamcrest:hamcrest-core:1.3"
+	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"
 }
 
 dependencyVerification {
 	verify = [
-			'com.google.dagger:dagger:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
-			'com.google.dagger:dagger-compiler:b74bc9de063dd4c6400b232231f2ef5056145b8fbecbf5382012007dd1c071b3',
-			'com.google.code.findbugs:jsr305:766ad2a0783f2687962c8ad74ceecc38a28b9f72a2d085ee438b7813e928d0c7',
-			'javax.inject:javax.inject:91c77044a50c481636c32d916fd89c9118a72195390452c81065080f957de7ff',
-			'com.google.dagger:dagger-producers:99ec15e8a0507ba569e7655bc1165ee5e5ca5aa914b3c8f7e2c2458f724edd6b',
-			'com.google.guava:guava:d664fbfc03d2e5ce9cab2a44fb01f1d0bf9dfebeccc1a473b1f9ea31f79f6f99',
+			'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:2.0.2: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',
+			'org.apache.ant:ant:1.9.4:ant-1.9.4.jar:649ae0730251de07b8913f49286d46bba7b92d47c5f332610aa426c4f02161d8',
+			'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
+			'org.hamcrest:hamcrest-core:1.3:hamcrest-core-1.3.jar:66fdef91e9739348df7a096aa384a5685f4e875584cce89386a7a47251c4d8e9',
+			'org.hamcrest:hamcrest-library:1.3:hamcrest-library-1.3.jar:711d64522f9ec410983bd310934296da134be4254a125080a0416ec178dfad1c',
+			'org.jmock:jmock-junit4:2.8.2:jmock-junit4-2.8.2.jar:f7ee4df4f7bd7b7f1cafad3b99eb74d579f109d5992ff625347352edb55e674c',
+			'org.jmock:jmock-legacy:2.8.2:jmock-legacy-2.8.2.jar:f2b985a5c08a9edb7f37612330c058809da3f6a6d63ce792426ebf8ff0d6d31b',
+			'org.jmock:jmock-testjar:2.8.2:jmock-testjar-2.8.2.jar:8900860f72c474e027cf97fe78dcbf154a1aa7fc62b6845c5fb4e4f3c7bc8760',
+			'org.jmock:jmock:2.8.2:jmock-2.8.2.jar:6c73cb4a2e6dbfb61fd99c9a768539c170ab6568e57846bd60dbf19596b65b16',
+			'org.objenesis:objenesis:2.1:objenesis-2.1.jar:c74330cc6b806c804fd37e74487b4fe5d7c2750c5e15fbc6efa13bdee1bdef80',
+			'org.ow2.asm:asm:5.0.4:asm-5.0.4.jar:896618ed8ae62702521a78bc7be42b7c491a08e6920a15f89a3ecdec31e9a220',
 	]
 }
 
@@ -39,3 +48,8 @@ task jarTest(type: Jar, dependsOn: testClasses) {
 artifacts {
 	testOutput jarTest
 }
+
+// If a Java 6 JRE is available, check we're not using any Java 7 or 8 APIs
+tasks.withType(JavaCompile) {
+	useJava6StandardLibrary(it)
+}

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

@@ -23,7 +23,7 @@ public class BdfMessageContext {
 	}
 
 	public BdfMessageContext(BdfDictionary dictionary) {
-		this(dictionary, Collections.<MessageId>emptyList());
+		this(dictionary, Collections.emptyList());
 	}
 
 	public BdfDictionary getDictionary() {

bramble-api/src/main/java/org/briarproject/bramble/api/crypto/CryptoComponent.java

@@ -10,8 +10,6 @@ public interface CryptoComponent {
 
 	SecretKey generateSecretKey();
 
-	PseudoRandom getPseudoRandom(int seed1, int seed2);
-
 	SecureRandom getSecureRandom();
 
 	KeyPair generateAgreementKeyPair();
@@ -24,15 +22,6 @@ public interface CryptoComponent {
 
 	KeyParser getMessageKeyParser();
 
-	/** Generates a random invitation code. */
-	int generateBTInvitationCode();
-
-	/**
-	 * Derives a confirmation code from the given master secret.
-	 * @param alice whether the code is for use by Alice or Bob.
-	 */
-	int deriveBTConfirmationCode(SecretKey master, boolean alice);
-
 	/**
 	 * Derives a stream header key from the given master secret.
 	 * @param alice whether the key is for use by Alice or Bob.

bramble-api/src/main/java/org/briarproject/bramble/api/crypto/PseudoRandom.java

@@ -1,12 +0,0 @@
-package org.briarproject.bramble.api.crypto;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-/**
- * A deterministic pseudo-random number generator.
- */
-@NotNullByDefault
-public interface PseudoRandom {
-
-	byte[] nextBytes(int bytes);
-}

bramble-api/src/main/java/org/briarproject/bramble/api/crypto/StreamDecrypterFactory.java

@@ -14,8 +14,9 @@ public interface StreamDecrypterFactory {
 	StreamDecrypter createStreamDecrypter(InputStream in, StreamContext ctx);
 
 	/**
-	 * Creates a {@link StreamDecrypter} for decrypting an invitation stream.
+	 * Creates a {@link StreamDecrypter} for decrypting a contact exchange
+	 * stream.
 	 */
-	StreamDecrypter createInvitationStreamDecrypter(InputStream in,
+	StreamDecrypter createContactExchangeStreamDecrypter(InputStream in,
 			SecretKey headerKey);
 }

bramble-api/src/main/java/org/briarproject/bramble/api/crypto/StreamEncrypterFactory.java

@@ -14,8 +14,9 @@ public interface StreamEncrypterFactory {
 	StreamEncrypter createStreamEncrypter(OutputStream out, StreamContext ctx);
 
 	/**
-	 * Creates a {@link StreamEncrypter} for encrypting an invitation stream.
+	 * Creates a {@link StreamEncrypter} for encrypting a contact exchange
+	 * stream.
 	 */
-	StreamEncrypter createInvitationStreamEncrypter(OutputStream out,
+	StreamEncrypter createContactExchangeStreamDecrypter(OutputStream out,
 			SecretKey headerKey);
 }

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

@@ -4,11 +4,14 @@ import org.briarproject.bramble.api.Bytes;
 import org.briarproject.bramble.api.FormatException;
 
 import java.util.Map;
-import java.util.concurrent.ConcurrentSkipListMap;
+import java.util.Map.Entry;
+import java.util.TreeMap;
 
 import javax.annotation.Nullable;
+import javax.annotation.concurrent.NotThreadSafe;
 
-public class BdfDictionary extends ConcurrentSkipListMap<String, Object> {
+@NotThreadSafe
+public class BdfDictionary extends TreeMap<String, Object> {
 
 	public static final Object NULL_VALUE = new Object();
 

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

@@ -3,15 +3,17 @@ package org.briarproject.bramble.api.data;
 import org.briarproject.bramble.api.Bytes;
 import org.briarproject.bramble.api.FormatException;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
-import java.util.Vector;
 
 import javax.annotation.Nullable;
+import javax.annotation.concurrent.NotThreadSafe;
 
 import static org.briarproject.bramble.api.data.BdfDictionary.NULL_VALUE;
 
-public class BdfList extends Vector<Object> {
+@NotThreadSafe
+public class BdfList extends ArrayList<Object> {
 
 	/**
 	 * Factory method for constructing lists inline.

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

@@ -0,0 +1,7 @@
+package org.briarproject.bramble.api.db;
+
+/**
+ * Thrown when the database uses a newer schema than the current code.
+ */
+public class DataTooNewException extends DbException {
+}

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

@@ -0,0 +1,8 @@
+package org.briarproject.bramble.api.db;
+
+/**
+ * Thrown when the database uses an older schema than the current code and
+ * cannot be migrated.
+ */
+public class DataTooOldException extends DbException {
+}

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

@@ -37,8 +37,13 @@ public interface DatabaseComponent {
 
 	/**
 	 * Opens the database and returns true if the database already existed.
+	 *
+	 * @throws DataTooNewException if the data uses a newer schema than the
+	 * current code
+	 * @throws DataTooOldException if the data uses an older schema than the
+	 * current code and cannot be migrated
 	 */
-	boolean open() throws DbException;
+	boolean open(@Nullable MigrationListener listener) throws DbException;
 
 	/**
 	 * Waits for any open transactions to finish and closes the database.
@@ -122,8 +127,9 @@ public interface DatabaseComponent {
 			throws DbException;
 
 	/**
-	 * Deletes the message with the given ID. The message ID and any other
-	 * associated data are not deleted.
+	 * Deletes the message with the given ID. Unlike
+	 * {@link #removeMessage(Transaction, MessageId)}, the message ID and any
+	 * other associated data are not deleted.
 	 */
 	void deleteMessage(Transaction txn, MessageId m) throws DbException;
 
@@ -372,6 +378,16 @@ public interface DatabaseComponent {
 	MessageStatus getMessageStatus(Transaction txn, ContactId c, MessageId m)
 			throws DbException;
 
+	/*
+	 * Returns the next time (in milliseconds since the Unix epoch) when a
+	 * message is due to be sent to the given contact. The returned value may
+	 * be zero if a message is due to be sent immediately, or Long.MAX_VALUE if
+	 * no messages are scheduled to be sent.
+	 * <p/>
+	 * Read-only.
+	 */
+	long getNextSendTime(Transaction txn, ContactId c) throws DbException;
+
 	/**
 	 * Returns all settings in the given namespace.
 	 * <p/>
@@ -452,6 +468,11 @@ public interface DatabaseComponent {
 	 */
 	void removeLocalAuthor(Transaction txn, AuthorId a) throws DbException;
 
+	/**
+	 * Removes a message (and all associated state) from the database.
+	 */
+	void removeMessage(Transaction txn, MessageId m) throws DbException;
+
 	/**
 	 * Removes a transport (and all associated state) from the database.
 	 */

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

@@ -1,11 +1,11 @@
 package org.briarproject.bramble.api.db;
 
-import java.util.Hashtable;
+import java.util.TreeMap;
 
-import javax.annotation.concurrent.ThreadSafe;
+import javax.annotation.concurrent.NotThreadSafe;
 
-@ThreadSafe
-public class Metadata extends Hashtable<String, byte[]> {
+@NotThreadSafe
+public class Metadata extends TreeMap<String, byte[]> {
 
 	/**
 	 * Special value to indicate that a key is being removed.

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

@@ -0,0 +1,11 @@
+package org.briarproject.bramble.api.db;
+
+public interface MigrationListener {
+
+	/**
+	 * This is called when a migration is started while opening the database.
+	 * It will be called once for each migration being applied.
+	 */
+	void onMigrationRun();
+
+}

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

@@ -45,7 +45,7 @@ public class Transaction {
 	 * committed.
 	 */
 	public void attach(Event e) {
-		if (events == null) events = new ArrayList<Event>();
+		if (events == null) events = new ArrayList<>();
 		events.add(e);
 	}
 

bramble-api/src/main/java/org/briarproject/bramble/api/invitation/InvitationConstants.java

@@ -1,20 +0,0 @@
-package org.briarproject.bramble.api.invitation;
-
-public interface InvitationConstants {
-
-	/**
-	 * The connection timeout in milliseconds.
-	 */
-	long CONNECTION_TIMEOUT = 60 * 1000;
-
-	/**
-	 * The confirmation timeout in milliseconds.
-	 */
-	long CONFIRMATION_TIMEOUT = 60 * 1000;
-
-	/**
-	 * The number of bits in an invitation or confirmation code. Codes must fit
-	 * into six decimal digits.
-	 */
-	int CODE_BITS = 19;
-}

bramble-api/src/main/java/org/briarproject/bramble/api/invitation/InvitationListener.java

@@ -1,47 +0,0 @@
-package org.briarproject.bramble.api.invitation;
-
-/**
- * An interface for receiving updates about the state of an
- * {@link InvitationTask}.
- */
-public interface InvitationListener {
-
-	/** Called if a connection to the remote peer is established. */
-	void connectionSucceeded();
-
-	/**
-	 * Called if a connection to the remote peer cannot be established. This
-	 * indicates that the protocol has ended unsuccessfully.
-	 */
-	void connectionFailed();
-
-	/** Called if key agreement with the remote peer succeeds. */
-	void keyAgreementSucceeded(int localCode, int remoteCode);
-
-	/**
-	 * Called if key agreement with the remote peer fails or the connection is
-	 * lost. This indicates that the protocol has ended unsuccessfully.
-	 */
-	void keyAgreementFailed();
-
-	/** Called if the remote peer's confirmation check succeeds. */
-	void remoteConfirmationSucceeded();
-
-	/**
-	 * Called if remote peer's confirmation check fails or the connection is
-	 * lost. This indicates that the protocol has ended unsuccessfully.
-	 */
-	void remoteConfirmationFailed();
-
-	/**
-	 * Called if the exchange of pseudonyms succeeds. This indicates that the
-	 * protocol has ended successfully.
-	 */
-	void pseudonymExchangeSucceeded(String remoteName);
-
-	/**
-	 * Called if the exchange of pseudonyms fails or the connection is lost.
-	 * This indicates that the protocol has ended unsuccessfully.
-	 */
-	void pseudonymExchangeFailed();
-}

bramble-api/src/main/java/org/briarproject/bramble/api/invitation/InvitationState.java

@@ -1,85 +0,0 @@
-package org.briarproject.bramble.api.invitation;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-import javax.annotation.Nullable;
-import javax.annotation.concurrent.Immutable;
-
-/**
- * A snapshot of the state of an {@link InvitationTask}.
- */
-@Immutable
-@NotNullByDefault
-public class InvitationState {
-
-	private final int localInvitationCode, remoteInvitationCode;
-	private final int localConfirmationCode, remoteConfirmationCode;
-	private final boolean connected, connectionFailed;
-	private final boolean localCompared, remoteCompared;
-	private final boolean localMatched, remoteMatched;
-	@Nullable
-	private final String contactName;
-
-	public InvitationState(int localInvitationCode, int remoteInvitationCode,
-			int localConfirmationCode, int remoteConfirmationCode,
-			boolean connected, boolean connectionFailed, boolean localCompared,
-			boolean remoteCompared, boolean localMatched,
-			boolean remoteMatched, @Nullable String contactName) {
-		this.localInvitationCode = localInvitationCode;
-		this.remoteInvitationCode = remoteInvitationCode;
-		this.localConfirmationCode = localConfirmationCode;
-		this.remoteConfirmationCode = remoteConfirmationCode;
-		this.connected = connected;
-		this.connectionFailed = connectionFailed;
-		this.localCompared = localCompared;
-		this.remoteCompared = remoteCompared;
-		this.localMatched = localMatched;
-		this.remoteMatched = remoteMatched;
-		this.contactName = contactName;
-	}
-
-	public int getLocalInvitationCode() {
-		return localInvitationCode;
-	}
-
-	public int getRemoteInvitationCode() {
-		return remoteInvitationCode;
-	}
-
-	public int getLocalConfirmationCode() {
-		return localConfirmationCode;
-	}
-
-	public int getRemoteConfirmationCode() {
-		return remoteConfirmationCode;
-	}
-
-	public boolean getConnected() {
-		return connected;
-	}
-
-	public boolean getConnectionFailed() {
-		return connectionFailed;
-	}
-
-	public boolean getLocalCompared() {
-		return localCompared;
-	}
-
-	public boolean getRemoteCompared() {
-		return remoteCompared;
-	}
-
-	public boolean getLocalMatched() {
-		return localMatched;
-	}
-
-	public boolean getRemoteMatched() {
-		return remoteMatched;
-	}
-
-	@Nullable
-	public String getContactName() {
-		return contactName;
-	}
-}

bramble-api/src/main/java/org/briarproject/bramble/api/invitation/InvitationTask.java

@@ -1,38 +0,0 @@
-package org.briarproject.bramble.api.invitation;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-/**
- * A task for exchanging invitations with a remote peer.
- */
-@NotNullByDefault
-public interface InvitationTask {
-
-	/**
-	 * Adds a listener to be informed of state changes and returns the
-	 * task's current state.
-	 */
-	InvitationState addListener(InvitationListener l);
-
-	/**
-	 * Removes the given listener.
-	 */
-	void removeListener(InvitationListener l);
-
-	/**
-	 * Asynchronously starts the connection process.
-	 */
-	void connect();
-
-	/**
-	 * Asynchronously informs the remote peer that the local peer's
-	 * confirmation codes matched.
-	 */
-	void localConfirmationSucceeded();
-
-	/**
-	 * Asynchronously informs the remote peer that the local peer's
-	 * confirmation codes did not match.
-	 */
-	void localConfirmationFailed();
-}

bramble-api/src/main/java/org/briarproject/bramble/api/invitation/InvitationTaskFactory.java

@@ -1,15 +0,0 @@
-package org.briarproject.bramble.api.invitation;
-
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-
-/**
- * Creates tasks for exchanging invitations with remote peers.
- */
-@NotNullByDefault
-public interface InvitationTaskFactory {
-
-	/**
-	 * Creates a task using the given local and remote invitation codes.
-	 */
-	InvitationTask createTask(int localCode, int remoteCode);
-}

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

@@ -2,7 +2,7 @@ package org.briarproject.bramble.api.keyagreement;
 
 import org.briarproject.bramble.api.data.BdfList;
 
-import java.util.concurrent.Callable;
+import java.io.IOException;
 
 /**
  * An class for managing a particular key agreement listener.
@@ -24,11 +24,11 @@ public abstract class KeyAgreementListener {
 	}
 
 	/**
-	 * Starts listening for incoming connections, and returns a Callable that
-	 * will return a KeyAgreementConnection when an incoming connection is
-	 * received.
+	 * Blocks until an incoming connection is received and returns it.
+	 *
+	 * @throws IOException if an error occurs or {@link #close()} is called.
 	 */
-	public abstract Callable<KeyAgreementConnection> listen();
+	public abstract KeyAgreementConnection accept() throws IOException;
 
 	/**
 	 * Closes the underlying server socket.

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

@@ -21,7 +21,25 @@ public interface LifecycleManager {
 	 * The result of calling {@link #startServices(String)}.
 	 */
 	enum StartResult {
-		ALREADY_RUNNING, DB_ERROR, SERVICE_ERROR, SUCCESS
+		ALREADY_RUNNING,
+		DB_ERROR,
+		DATA_TOO_OLD_ERROR,
+		DATA_TOO_NEW_ERROR,
+		SERVICE_ERROR,
+		SUCCESS
+	}
+
+	/**
+	 * The state the lifecycle can be in.
+	 * Returned by {@link #getLifecycleState()}
+	 */
+	enum LifecycleState {
+
+		STARTING, MIGRATING_DATABASE, STARTING_SERVICES, RUNNING, STOPPING;
+
+		public boolean isAfter(LifecycleState state) {
+			return ordinal() > state.ordinal();
+		}
 	}
 
 	/**
@@ -71,4 +89,10 @@ public interface LifecycleManager {
 	 * the {@link DatabaseComponent} to be closed before returning.
 	 */
 	void waitForShutdown() throws InterruptedException;
+
+	/**
+	 * Returns the current state of the lifecycle.
+	 */
+	LifecycleState getLifecycleState();
+
 }

bramble-api/src/main/java/org/briarproject/bramble/api/lifecycle/event/LifecycleEvent.java

@@ -0,0 +1,20 @@
+package org.briarproject.bramble.api.lifecycle.event;
+
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState;
+
+/**
+ * An event that is broadcast when the app enters a new lifecycle state.
+ */
+public class LifecycleEvent extends Event {
+
+	private final LifecycleState state;
+
+	public LifecycleEvent(LifecycleState state) {
+		this.state = state;
+	}
+
+	public LifecycleState getLifecycleState() {
+		return state;
+	}
+}

bramble-api/src/main/java/org/briarproject/bramble/api/lifecycle/event/ShutdownEvent.java

@@ -1,9 +0,0 @@
-package org.briarproject.bramble.api.lifecycle.event;
-
-import org.briarproject.bramble.api.event.Event;
-
-/**
- * An event that is broadcast when the app is shutting down.
- */
-public class ShutdownEvent extends Event {
-}

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

@@ -4,5 +4,10 @@ public interface LanTcpConstants {
 
 	TransportId ID = new TransportId("org.briarproject.bramble.lan");
 
+	// a transport property (shared with contacts)
+	String PROP_IP_PORTS = "ipPorts";
+
+	// a local setting
 	String PREF_LAN_IP_PORTS = "ipPorts";
+
 }

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

@@ -29,6 +29,11 @@ public interface PluginCallback {
 	 */
 	Map<ContactId, TransportProperties> getRemoteProperties();
 
+	/**
+	 * Returns the plugin's remote transport properties for the given contact.
+	 */
+	TransportProperties getRemoteProperties(ContactId c);
+
 	/**
 	 * Merges the given settings with the namespaced settings
 	 */

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

@@ -32,11 +32,6 @@ public interface PluginManager {
 	 */
 	Collection<DuplexPlugin> getDuplexPlugins();
 
-	/**
-	 * Returns any duplex plugins that support invitations.
-	 */
-	Collection<DuplexPlugin> getInvitationPlugins();
-
 	/**
 	 * Returns any duplex plugins that support key agreement.
 	 */

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

@@ -4,6 +4,8 @@ public interface TorConstants {
 
 	TransportId ID = new TransportId("org.briarproject.bramble.tor");
 
+	String PROP_ONION = "onion";
+
 	int SOCKS_PORT = 59050;
 	int CONTROL_PORT = 59051;
 
@@ -16,4 +18,5 @@ public interface TorConstants {
 	int PREF_TOR_NETWORK_NEVER = 0;
 	int PREF_TOR_NETWORK_WIFI = 1;
 	int PREF_TOR_NETWORK_ALWAYS = 2;
+
 }

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

@@ -1,7 +1,6 @@
 package org.briarproject.bramble.api.plugin.duplex;
 
 import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.crypto.PseudoRandom;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
@@ -23,20 +22,6 @@ public interface DuplexPlugin extends Plugin {
 	@Nullable
 	DuplexTransportConnection createConnection(ContactId c);
 
-	/**
-	 * Returns true if the plugin supports exchanging invitations.
-	 */
-	boolean supportsInvitations();
-
-	/**
-	 * Attempts to create and return an invitation connection to the remote
-	 * peer. Returns null if no connection can be established within the given
-	 * time.
-	 */
-	@Nullable
-	DuplexTransportConnection createInvitationConnection(PseudoRandom r,
-			long timeout, boolean alice);
-
 	/**
 	 * Returns true if the plugin supports short-range key agreement.
 	 */
@@ -51,9 +36,9 @@ public interface DuplexPlugin extends Plugin {
 
 	/**
 	 * Attempts to connect to the remote peer specified in the given descriptor.
-	 * Returns null if no connection can be established within the given time.
+	 * Returns null if no connection can be established.
 	 */
 	@Nullable
 	DuplexTransportConnection createKeyAgreementConnection(
-			byte[] remoteCommitment, BdfList descriptor, long timeout);
+			byte[] remoteCommitment, BdfList descriptor);
 }

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/event/BluetoothEnabledEvent.java

@@ -0,0 +1,15 @@
+package org.briarproject.bramble.api.plugin.event;
+
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * An event that informs the Bluetooth plugin that we have enabled the
+ * Bluetooth adapter.
+ */
+@Immutable
+@NotNullByDefault
+public class BluetoothEnabledEvent extends Event {
+}

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/event/DisableBluetoothEvent.java

@@ -0,0 +1,15 @@
+package org.briarproject.bramble.api.plugin.event;
+
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * An event that asks the Bluetooth plugin to disable the Bluetooth adapter if
+ * we previously enabled it.
+ */
+@Immutable
+@NotNullByDefault
+public class DisableBluetoothEvent extends Event {
+}

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/event/EnableBluetoothEvent.java

@@ -0,0 +1,14 @@
+package org.briarproject.bramble.api.plugin.event;
+
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * An event that asks the Bluetooth plugin to enable the Bluetooth adapter.
+ */
+@Immutable
+@NotNullByDefault
+public class EnableBluetoothEvent extends Event {
+}

bramble-api/src/main/java/org/briarproject/bramble/api/properties/TransportPropertyManager.java

@@ -33,7 +33,7 @@ public interface TransportPropertyManager {
 	/**
 	 * Returns the local transport properties for all transports.
 	 * <br/>
-	 * Read-Only
+	 * TODO: Transaction can be read-only when code is simplified
 	 */
 	Map<TransportId, TransportProperties> getLocalProperties(Transaction txn)
 			throws DbException;
@@ -49,6 +49,13 @@ public interface TransportPropertyManager {
 	Map<ContactId, TransportProperties> getRemoteProperties(TransportId t)
 			throws DbException;
 
+	/**
+	 * Returns the remote transport properties for the given contact and
+	 * transport.
+	 */
+	TransportProperties getRemoteProperties(ContactId c, TransportId t)
+			throws DbException;
+
 	/**
 	 * Merges the given properties with the existing local properties for the
 	 * given transport.

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

@@ -22,7 +22,7 @@ public class MessageContext {
 	}
 
 	public MessageContext(Metadata metadata) {
-		this(metadata, Collections.<MessageId>emptyList());
+		this(metadata, Collections.emptyList());
 	}
 
 	public Metadata getMetadata() {

bramble-api/src/main/java/org/briarproject/bramble/api/transport/StreamReaderFactory.java

@@ -15,9 +15,9 @@ public interface StreamReaderFactory {
 	InputStream createStreamReader(InputStream in, StreamContext ctx);
 
 	/**
-	 * Creates an {@link InputStream InputStream} for reading from an
-	 * invitation stream.
+	 * Creates an {@link InputStream InputStream} for reading from a contact
+	 * exchangestream.
 	 */
-	InputStream createInvitationStreamReader(InputStream in,
+	InputStream createContactExchangeStreamReader(InputStream in,
 			SecretKey headerKey);
 }

bramble-api/src/main/java/org/briarproject/bramble/api/transport/StreamWriterFactory.java

@@ -15,9 +15,9 @@ public interface StreamWriterFactory {
 	OutputStream createStreamWriter(OutputStream out, StreamContext ctx);
 
 	/**
-	 * Creates an {@link OutputStream OutputStream} for writing to an
-	 * invitation stream.
+	 * Creates an {@link OutputStream OutputStream} for writing to a contact
+	 * exchange stream.
 	 */
-	OutputStream createInvitationStreamWriter(OutputStream out,
+	OutputStream createContactExchangeStreamWriter(OutputStream out,
 			SecretKey headerKey);
 }

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

@@ -8,6 +8,7 @@ import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.net.Socket;
 
 import javax.annotation.Nullable;
 
@@ -59,4 +60,24 @@ public class IoUtils {
 			offset += read;
 		}
 	}
+
+	// Workaround for a bug in Android 7, see
+	// https://android-review.googlesource.com/#/c/271775/
+	public static InputStream getInputStream(Socket s) throws IOException {
+		try {
+			return s.getInputStream();
+		} catch (NullPointerException e) {
+			throw new IOException(e);
+		}
+	}
+
+	// Workaround for a bug in Android 7, see
+	// https://android-review.googlesource.com/#/c/271775/
+	public static OutputStream getOutputStream(Socket s) throws IOException {
+		try {
+			return s.getOutputStream();
+		} catch (NullPointerException e) {
+			throw new IOException(e);
+		}
+	}
 }

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

@@ -8,6 +8,7 @@ import java.nio.charset.CharacterCodingException;
 import java.nio.charset.Charset;
 import java.nio.charset.CharsetDecoder;
 import java.util.Collection;
+import java.util.Random;
 import java.util.regex.Pattern;
 
 import javax.annotation.Nullable;
@@ -27,6 +28,7 @@ public class StringUtils {
 			'0', '1', '2', '3', '4', '5', '6', '7',
 			'8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
 	};
+	private static final Random random = new Random();
 
 	public static boolean isNullOrEmpty(@Nullable String s) {
 		return s == null || s.length() == 0;
@@ -124,6 +126,10 @@ public class StringUtils {
 		return toUtf8(s).length > maxLength;
 	}
 
+	public static boolean isValidMac(String mac) {
+		return MAC.matcher(mac).matches();
+	}
+
 	public static byte[] macToBytes(String mac) {
 		if (!MAC.matcher(mac).matches()) throw new IllegalArgumentException();
 		return fromHexString(mac.replaceAll(":", ""));
@@ -139,4 +145,12 @@ public class StringUtils {
 		}
 		return s.toString();
 	}
+
+	public static String getRandomString(int length) {
+		char[] c = new char[length];
+		for (int i = 0; i < length; i++)
+			c[i] = (char) ('a' + random.nextInt(26));
+		return new String(c);
+	}
+
 }

bramble-api/src/test/java/org/briarproject/bramble/test/BrambleMockTestCase.java

@@ -3,8 +3,7 @@ package org.briarproject.bramble.test;
 import org.jmock.Mockery;
 import org.junit.After;
 
-public abstract class BrambleMockTestCase extends
-		BrambleTestCase {
+public abstract class BrambleMockTestCase extends BrambleTestCase {
 
 	protected final Mockery context = new Mockery();
 

bramble-api/src/test/java/org/briarproject/bramble/test/BrambleTestCase.java

@@ -8,12 +8,9 @@ public abstract class BrambleTestCase {
 
 	public BrambleTestCase() {
 		// Ensure exceptions thrown on worker threads cause tests to fail
-		UncaughtExceptionHandler fail = new UncaughtExceptionHandler() {
-			@Override
-			public void uncaughtException(Thread thread, Throwable throwable) {
-				throwable.printStackTrace();
-				fail();
-			}
+		UncaughtExceptionHandler fail = (thread, throwable) -> {
+			throwable.printStackTrace();
+			fail();
 		};
 		Thread.setDefaultUncaughtExceptionHandler(fail);
 	}

bramble-api/src/test/java/org/briarproject/bramble/test/TestUtils.java

@@ -2,12 +2,27 @@ package org.briarproject.bramble.test;
 
 import org.briarproject.bramble.api.UniqueId;
 import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.bramble.api.identity.AuthorId;
+import org.briarproject.bramble.api.identity.LocalAuthor;
+import org.briarproject.bramble.api.sync.ClientId;
+import org.briarproject.bramble.api.sync.Group;
+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.util.IoUtils;
 
 import java.io.File;
 import java.util.Random;
 import java.util.concurrent.atomic.AtomicInteger;
 
+import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_AUTHOR_NAME_LENGTH;
+import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
+import static org.briarproject.bramble.api.sync.SyncConstants.MAX_GROUP_DESCRIPTOR_LENGTH;
+import static org.briarproject.bramble.api.sync.SyncConstants.MAX_MESSAGE_BODY_LENGTH;
+import static org.briarproject.bramble.api.sync.SyncConstants.MESSAGE_HEADER_LENGTH;
+import static org.briarproject.bramble.util.StringUtils.getRandomString;
+
 public class TestUtils {
 
 	private static final AtomicInteger nextTestDir =
@@ -34,15 +49,54 @@ public class TestUtils {
 		return getRandomBytes(UniqueId.LENGTH);
 	}
 
-	public static String getRandomString(int length) {
-		char[] c = new char[length];
-		for (int i = 0; i < length; i++)
-			c[i] = (char) ('a' + random.nextInt(26));
-		return new String(c);
-	}
-
 	public static SecretKey getSecretKey() {
 		return new SecretKey(getRandomBytes(SecretKey.LENGTH));
 	}
 
+	public static LocalAuthor getLocalAuthor() {
+		return getLocalAuthor(1 + random.nextInt(MAX_AUTHOR_NAME_LENGTH));
+	}
+
+	public static LocalAuthor getLocalAuthor(int nameLength) {
+		AuthorId id = new AuthorId(getRandomId());
+		String name = getRandomString(nameLength);
+		byte[] publicKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
+		byte[] privateKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
+		long created = System.currentTimeMillis();
+		return new LocalAuthor(id, name, publicKey, privateKey, created);
+	}
+
+	public static Author getAuthor() {
+		return getAuthor(1 + random.nextInt(MAX_AUTHOR_NAME_LENGTH));
+	}
+
+	public static Author getAuthor(int nameLength) {
+		AuthorId id = new AuthorId(getRandomId());
+		String name = getRandomString(nameLength);
+		byte[] publicKey = getRandomBytes(MAX_PUBLIC_KEY_LENGTH);
+		return new Author(id, name, publicKey);
+	}
+
+	public static Group getGroup(ClientId clientId) {
+		int descriptorLength = 1 + random.nextInt(MAX_GROUP_DESCRIPTOR_LENGTH);
+		return getGroup(clientId, descriptorLength);
+	}
+
+	public static Group getGroup(ClientId clientId, int descriptorLength) {
+		GroupId groupId = new GroupId(getRandomId());
+		byte[] descriptor = getRandomBytes(descriptorLength);
+		return new Group(groupId, clientId, descriptor);
+	}
+
+	public static Message getMessage(GroupId groupId) {
+		int bodyLength = 1 + random.nextInt(MAX_MESSAGE_BODY_LENGTH);
+		return getMessage(groupId, MESSAGE_HEADER_LENGTH + bodyLength);
+	}
+
+	public static Message getMessage(GroupId groupId, int rawLength) {
+		MessageId id = new MessageId(getRandomId());
+		byte[] raw = getRandomBytes(rawLength);
+		long timestamp = System.currentTimeMillis();
+		return new Message(id, groupId, timestamp, raw);
+	}
 }

bramble-core/build.gradle

@@ -1,28 +1,54 @@
-plugins {
-	id 'java'
-	id 'net.ltgt.apt' version '0.9'
-	id 'idea'
-}
-
-sourceCompatibility = 1.6
-targetCompatibility = 1.6
+apply plugin: 'java-library'
+sourceCompatibility = 1.8
+targetCompatibility = 1.8
 
+apply plugin: 'net.ltgt.apt'
+apply plugin: 'idea'
 apply plugin: 'witness'
 
 dependencies {
-	compile project(':bramble-api')
-	compile 'com.madgag.spongycastle:core:1.56.0.0'
-	compile 'com.h2database:h2:1.4.192' // This is the last version that supports Java 1.6
-	compile 'org.bitlet:weupnp:0.1.4'
+	implementation project(path: ':bramble-api', configuration: 'default')
+	implementation 'com.madgag.spongycastle:core:1.58.0.0'
+	implementation 'com.h2database:h2:1.4.192' // This is the last version that supports Java 1.6
+	implementation 'org.bitlet:weupnp:0.1.4'
 
-	testCompile project(path: ':bramble-api', configuration: 'testOutput')
+	apt 'com.google.dagger:dagger-compiler:2.0.2'
+
+	testImplementation project(path: ':bramble-api', configuration: 'testOutput')
+	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"
+
+	testApt 'com.google.dagger:dagger-compiler:2.0.2'
 }
 
 dependencyVerification {
 	verify = [
-			'com.madgag.spongycastle:core:5e791b0eaa9e0c4594231b44f616a52adddb7dccedeb0ad9ad74887e19499a23',
-			'com.h2database:h2:225b22e9857235c46c93861410b60b8c81c10dc8985f4faf188985ba5445126c',
-			'org.bitlet:weupnp:88df7e6504929d00bdb832863761385c68ab92af945b04f0770b126270a444fb',
+			'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-compiler:2.0.2:dagger-compiler-2.0.2.jar:b74bc9de063dd4c6400b232231f2ef5056145b8fbecbf5382012007dd1c071b3',
+			'com.google.dagger:dagger-producers:2.0-beta:dagger-producers-2.0-beta.jar:99ec15e8a0507ba569e7655bc1165ee5e5ca5aa914b3c8f7e2c2458f724edd6b',
+			'com.google.dagger:dagger:2.0.2:dagger-2.0.2.jar:84c0282ed8be73a29e0475d639da030b55dee72369e58dd35ae7d4fe6243dcf9',
+			'com.google.guava:guava:18.0:guava-18.0.jar:d664fbfc03d2e5ce9cab2a44fb01f1d0bf9dfebeccc1a473b1f9ea31f79f6f99',
+			'com.h2database:h2:1.4.192:h2-1.4.192.jar:225b22e9857235c46c93861410b60b8c81c10dc8985f4faf188985ba5445126c',
+			'com.madgag.spongycastle:core:1.58.0.0:core-1.58.0.0.jar:199617dd5698c5a9312b898c0a4cec7ce9dd8649d07f65d91629f58229d72728',
+			'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',
+			'org.apache.ant:ant:1.9.4:ant-1.9.4.jar:649ae0730251de07b8913f49286d46bba7b92d47c5f332610aa426c4f02161d8',
+			'org.beanshell:bsh:1.3.0:bsh-1.3.0.jar:9b04edc75d19db54f1b4e8b5355e9364384c6cf71eb0a1b9724c159d779879f8',
+			'org.bitlet:weupnp:0.1.4:weupnp-0.1.4.jar:88df7e6504929d00bdb832863761385c68ab92af945b04f0770b126270a444fb',
+			'org.hamcrest:hamcrest-core:1.3:hamcrest-core-1.3.jar:66fdef91e9739348df7a096aa384a5685f4e875584cce89386a7a47251c4d8e9',
+			'org.hamcrest:hamcrest-library:1.3:hamcrest-library-1.3.jar:711d64522f9ec410983bd310934296da134be4254a125080a0416ec178dfad1c',
+			'org.jmock:jmock-junit4:2.8.2:jmock-junit4-2.8.2.jar:f7ee4df4f7bd7b7f1cafad3b99eb74d579f109d5992ff625347352edb55e674c',
+			'org.jmock:jmock-legacy:2.8.2:jmock-legacy-2.8.2.jar:f2b985a5c08a9edb7f37612330c058809da3f6a6d63ce792426ebf8ff0d6d31b',
+			'org.jmock:jmock-testjar:2.8.2:jmock-testjar-2.8.2.jar:8900860f72c474e027cf97fe78dcbf154a1aa7fc62b6845c5fb4e4f3c7bc8760',
+			'org.jmock:jmock:2.8.2:jmock-2.8.2.jar:6c73cb4a2e6dbfb61fd99c9a768539c170ab6568e57846bd60dbf19596b65b16',
+			'org.objenesis:objenesis:2.1:objenesis-2.1.jar:c74330cc6b806c804fd37e74487b4fe5d7c2750c5e15fbc6efa13bdee1bdef80',
+			'org.ow2.asm:asm:5.0.4:asm-5.0.4.jar:896618ed8ae62702521a78bc7be42b7c491a08e6920a15f89a3ecdec31e9a220',
 	]
 }
 
@@ -37,3 +63,8 @@ task jarTest(type: Jar, dependsOn: testClasses) {
 artifacts {
 	testOutput jarTest
 }
+
+// If a Java 6 JRE is available, check we're not using any Java 7 or 8 APIs
+tasks.withType(JavaCompile) {
+	useJava6StandardLibrary(it)
+}

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

@@ -8,7 +8,6 @@ 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.invitation.InvitationModule;
 import org.briarproject.bramble.keyagreement.KeyAgreementModule;
 import org.briarproject.bramble.lifecycle.LifecycleModule;
 import org.briarproject.bramble.plugin.PluginModule;
@@ -32,7 +31,6 @@ import dagger.Module;
 		DatabaseExecutorModule.class,
 		EventModule.class,
 		IdentityModule.class,
-		InvitationModule.class,
 		KeyAgreementModule.class,
 		LifecycleModule.class,
 		PluginModule.class,

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

@@ -24,7 +24,7 @@ public class PoliteExecutor implements Executor {
 
 	private final Object lock = new Object();
 	@GuardedBy("lock")
-	private final Queue<Runnable> queue = new LinkedList<Runnable>();
+	private final Queue<Runnable> queue = new LinkedList<>();
 	private final Executor delegate;
 	private final int maxConcurrentTasks;
 	private final Logger log;
@@ -48,20 +48,17 @@ public class PoliteExecutor implements Executor {
 	}
 
 	@Override
-	public void execute(final Runnable r) {
-		final long submitted = System.currentTimeMillis();
-		Runnable wrapped = new Runnable() {
-			@Override
-			public void run() {
-				if (log.isLoggable(LOG_LEVEL)) {
-					long queued = System.currentTimeMillis() - submitted;
-					log.log(LOG_LEVEL, "Queue time " + queued + " ms");
-				}
-				try {
-					r.run();
-				} finally {
-					scheduleNext();
-				}
+	public void execute(Runnable r) {
+		long submitted = System.currentTimeMillis();
+		Runnable wrapped = () -> {
+			if (log.isLoggable(LOG_LEVEL)) {
+				long queued = System.currentTimeMillis() - submitted;
+				log.log(LOG_LEVEL, "Queue time " + queued + " ms");
+			}
+			try {
+				r.run();
+			} finally {
+				scheduleNext();
 			}
 		};
 		synchronized (lock) {

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

@@ -28,19 +28,16 @@ public class TimeLoggingExecutor extends ThreadPoolExecutor {
 	}
 
 	@Override
-	public void execute(final Runnable r) {
+	public void execute(Runnable r) {
 		if (log.isLoggable(LOG_LEVEL)) {
-			final long submitted = System.currentTimeMillis();
-			super.execute(new Runnable() {
-				@Override
-				public void run() {
-					long started = System.currentTimeMillis();
-					long queued = started - submitted;
-					log.log(LOG_LEVEL, "Queue time " + queued + " ms");
-					r.run();
-					long executing = System.currentTimeMillis() - started;
-					log.log(LOG_LEVEL, "Execution time " + executing + " ms");
-				}
+			long submitted = System.currentTimeMillis();
+			super.execute(() -> {
+				long started = System.currentTimeMillis();
+				long queued = started - submitted;
+				log.log(LOG_LEVEL, "Queue time " + queued + " ms");
+				r.run();
+				long executing = System.currentTimeMillis() - started;
+				log.log(LOG_LEVEL, "Execution time " + executing + " ms");
 			});
 		} else {
 			super.execute(r);

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

@@ -201,8 +201,7 @@ class ClientHelperImpl implements ClientHelper {
 	public Map<MessageId, BdfDictionary> getMessageMetadataAsDictionary(
 			Transaction txn, GroupId g) throws DbException, FormatException {
 		Map<MessageId, Metadata> raw = db.getMessageMetadata(txn, g);
-		Map<MessageId, BdfDictionary> parsed =
-				new HashMap<MessageId, BdfDictionary>(raw.size());
+		Map<MessageId, BdfDictionary> parsed = new HashMap<>(raw.size());
 		for (Entry<MessageId, Metadata> e : raw.entrySet())
 			parsed.put(e.getKey(), metadataParser.parse(e.getValue()));
 		return parsed;
@@ -229,8 +228,7 @@ class ClientHelperImpl implements ClientHelper {
 			FormatException {
 		Metadata metadata = metadataEncoder.encode(query);
 		Map<MessageId, Metadata> raw = db.getMessageMetadata(txn, g, metadata);
-		Map<MessageId, BdfDictionary> parsed =
-				new HashMap<MessageId, BdfDictionary>(raw.size());
+		Map<MessageId, BdfDictionary> parsed = new HashMap<>(raw.size());
 		for (Entry<MessageId, Metadata> e : raw.entrySet())
 			parsed.put(e.getKey(), metadataParser.parse(e.getValue()));
 		return parsed;

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

@@ -80,7 +80,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 	private volatile boolean alice;
 
 	@Inject
-	public ContactExchangeTaskImpl(DatabaseComponent db,
+	ContactExchangeTaskImpl(DatabaseComponent db,
 			AuthorFactory authorFactory, BdfReaderFactory bdfReaderFactory,
 			BdfWriterFactory bdfWriterFactory, Clock clock,
 			ConnectionManager connectionManager, ContactManager contactManager,
@@ -146,12 +146,12 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 
 		// Create the readers
 		InputStream streamReader =
-				streamReaderFactory.createInvitationStreamReader(in,
+				streamReaderFactory.createContactExchangeStreamReader(in,
 						alice ? bobHeaderKey : aliceHeaderKey);
 		BdfReader r = bdfReaderFactory.createReader(streamReader);
 		// Create the writers
 		OutputStream streamWriter =
-				streamWriterFactory.createInvitationStreamWriter(out,
+				streamWriterFactory.createContactExchangeStreamWriter(out,
 						alice ? aliceHeaderKey : bobHeaderKey);
 		BdfWriter w = bdfWriterFactory.createWriter(streamWriter);
 
@@ -184,12 +184,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 			// Close the outgoing stream and expect EOF on the incoming stream
 			w.close();
 			if (!r.eof()) LOG.warning("Unexpected data at end of connection");
-		} catch (GeneralSecurityException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			listener.contactExchangeFailed();
-			tryToClose(conn, true);
-			return;
-		} catch (IOException e) {
+		} catch (GeneralSecurityException | IOException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			listener.contactExchangeFailed();
 			tryToClose(conn, true);
@@ -276,8 +271,7 @@ class ContactExchangeTaskImpl extends Thread implements ContactExchangeTask {
 
 	private Map<TransportId, TransportProperties> receiveTransportProperties(
 			BdfReader r) throws IOException {
-		Map<TransportId, TransportProperties> remote =
-				new HashMap<TransportId, TransportProperties>();
+		Map<TransportId, TransportProperties> remote = new HashMap<>();
 		r.readListStart();
 		while (!r.hasListEnd()) {
 			r.readListStart();

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

@@ -34,8 +34,8 @@ class ContactManagerImpl implements ContactManager {
 	ContactManagerImpl(DatabaseComponent db, KeyManager keyManager) {
 		this.db = db;
 		this.keyManager = keyManager;
-		addHooks = new CopyOnWriteArrayList<AddContactHook>();
-		removeHooks = new CopyOnWriteArrayList<RemoveContactHook>();
+		addHooks = new CopyOnWriteArrayList<>();
+		removeHooks = new CopyOnWriteArrayList<>();
 	}
 
 	@Override
@@ -125,7 +125,7 @@ class ContactManagerImpl implements ContactManager {
 		} finally {
 			db.endTransaction(txn);
 		}
-		List<Contact> active = new ArrayList<Contact>(contacts.size());
+		List<Contact> active = new ArrayList<>(contacts.size());
 		for (Contact c : contacts) if (c.isActive()) active.add(c);
 		return active;
 	}

bramble-core/src/main/java/org/briarproject/bramble/crypto/CryptoComponentImpl.java

@@ -4,7 +4,6 @@ import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.KeyPair;
 import org.briarproject.bramble.api.crypto.KeyParser;
 import org.briarproject.bramble.api.crypto.PrivateKey;
-import org.briarproject.bramble.api.crypto.PseudoRandom;
 import org.briarproject.bramble.api.crypto.PublicKey;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.plugin.TransportId;
@@ -41,7 +40,6 @@ import java.util.logging.Logger;
 import javax.inject.Inject;
 
 import static java.util.logging.Level.INFO;
-import static org.briarproject.bramble.api.invitation.InvitationConstants.CODE_BITS;
 import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.COMMIT_LENGTH;
 import static org.briarproject.bramble.api.transport.TransportConstants.TAG_LENGTH;
 import static org.briarproject.bramble.crypto.EllipticCurveConstants.PARAMETERS;
@@ -68,9 +66,6 @@ class CryptoComponentImpl implements CryptoComponent {
 		return s.getBytes(Charset.forName("US-ASCII"));
 	}
 
-	// KDF labels for bluetooth confirmation code derivation
-	private static final byte[] BT_A_CONFIRM = ascii("ALICE_CONFIRMATION_CODE");
-	private static final byte[] BT_B_CONFIRM = ascii("BOB_CONFIRMATION_CODE");
 	// KDF labels for contact exchange stream header key derivation
 	private static final byte[] A_INVITE = ascii("ALICE_INVITATION_KEY");
 	private static final byte[] B_INVITE = ascii("BOB_INVITATION_KEY");
@@ -171,14 +166,6 @@ class CryptoComponentImpl implements CryptoComponent {
 		return new SecretKey(b);
 	}
 
-	@Override
-	public PseudoRandom getPseudoRandom(int seed1, int seed2) {
-		byte[] seed = new byte[INT_32_BYTES * 2];
-		ByteUtils.writeUint32(seed1, seed, 0);
-		ByteUtils.writeUint32(seed2, seed, INT_32_BYTES);
-		return new PseudoRandomImpl(seed);
-	}
-
 	@Override
 	public SecureRandom getSecureRandom() {
 		return secureRandom;
@@ -250,20 +237,6 @@ class CryptoComponentImpl implements CryptoComponent {
 		return messageEncrypter.getKeyParser();
 	}
 
-	@Override
-	public int generateBTInvitationCode() {
-		int codeBytes = (CODE_BITS + 7) / 8;
-		byte[] random = new byte[codeBytes];
-		secureRandom.nextBytes(random);
-		return ByteUtils.readUint(random, CODE_BITS);
-	}
-
-	@Override
-	public int deriveBTConfirmationCode(SecretKey master, boolean alice) {
-		byte[] b = macKdf(master, alice ? BT_A_CONFIRM : BT_B_CONFIRM);
-		return ByteUtils.readUint(b, CODE_BITS);
-	}
-
 	@Override
 	public SecretKey deriveHeaderKey(SecretKey master,
 			boolean alice) {
@@ -629,8 +602,8 @@ class CryptoComponentImpl implements CryptoComponent {
 
 	// Package access for testing
 	int chooseIterationCount(int targetMillis) {
-		List<Long> quickSamples = new ArrayList<Long>(PBKDF_SAMPLES);
-		List<Long> slowSamples = new ArrayList<Long>(PBKDF_SAMPLES);
+		List<Long> quickSamples = new ArrayList<>(PBKDF_SAMPLES);
+		List<Long> slowSamples = new ArrayList<>(PBKDF_SAMPLES);
 		long iterationNanos = 0, initNanos = 0;
 		while (iterationNanos <= 0 || initNanos <= 0) {
 			// Sample the running time with one iteration and two iterations

bramble-core/src/main/java/org/briarproject/bramble/crypto/CryptoModule.java

@@ -48,7 +48,7 @@ public class CryptoModule {
 
 	public CryptoModule() {
 		// Use an unbounded queue
-		BlockingQueue<Runnable> queue = new LinkedBlockingQueue<Runnable>();
+		BlockingQueue<Runnable> queue = new LinkedBlockingQueue<>();
 		// Discard tasks that are submitted during shutdown
 		RejectedExecutionHandler policy =
 				new ThreadPoolExecutor.DiscardPolicy();

bramble-core/src/main/java/org/briarproject/bramble/crypto/PasswordStrengthEstimatorImpl.java

@@ -16,7 +16,7 @@ class PasswordStrengthEstimatorImpl implements PasswordStrengthEstimator {
 
 	@Override
 	public float estimateStrength(String password) {
-		HashSet<Character> unique = new HashSet<Character>();
+		HashSet<Character> unique = new HashSet<>();
 		int length = password.length();
 		for (int i = 0; i < length; i++) unique.add(password.charAt(i));
 		return Math.min(1, (float) unique.size() / STRONG_UNIQUE_CHARS);

bramble-core/src/main/java/org/briarproject/bramble/crypto/StreamDecrypterFactoryImpl.java

@@ -32,7 +32,7 @@ class StreamDecrypterFactoryImpl implements StreamDecrypterFactory {
 	}
 
 	@Override
-	public StreamDecrypter createInvitationStreamDecrypter(InputStream in,
+	public StreamDecrypter createContactExchangeStreamDecrypter(InputStream in,
 			SecretKey headerKey) {
 		return new StreamDecrypterImpl(in, cipherProvider.get(), 0, headerKey);
 	}

bramble-core/src/main/java/org/briarproject/bramble/crypto/StreamEncrypterFactoryImpl.java

@@ -46,8 +46,8 @@ class StreamEncrypterFactoryImpl implements StreamEncrypterFactory {
 	}
 
 	@Override
-	public StreamEncrypter createInvitationStreamEncrypter(OutputStream out,
-			SecretKey headerKey) {
+	public StreamEncrypter createContactExchangeStreamDecrypter(
+			OutputStream out, SecretKey headerKey) {
 		AuthenticatedCipher cipher = cipherProvider.get();
 		byte[] streamHeaderNonce = new byte[STREAM_HEADER_NONCE_LENGTH];
 		crypto.getSecureRandom().nextBytes(streamHeaderNonce);

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

@@ -2,8 +2,11 @@ package org.briarproject.bramble.db;
 
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.db.DataTooNewException;
+import org.briarproject.bramble.api.db.DataTooOldException;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Metadata;
+import org.briarproject.bramble.api.db.MigrationListener;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.identity.LocalAuthor;
@@ -37,8 +40,13 @@ interface Database<T> {
 
 	/**
 	 * Opens the database and returns true if the database already existed.
+	 *
+	 * @throws DataTooNewException if the data uses a newer schema than the
+	 * current code
+	 * @throws DataTooOldException if the data uses an older schema than the
+	 * current code and cannot be migrated
 	 */
-	boolean open() throws DbException;
+	boolean open(@Nullable MigrationListener listener) throws DbException;
 
 	/**
 	 * Prevents new transactions from starting, waits for all current
@@ -449,6 +457,16 @@ interface Database<T> {
 	Collection<MessageId> getMessagesToShare(T txn, ClientId c)
 			throws DbException;
 
+	/**
+	 * Returns the next time (in milliseconds since the Unix epoch) when a
+	 * message is due to be sent to the given contact. The returned value may
+	 * be zero if a message is due to be sent immediately, or Long.MAX_VALUE
+	 * if no messages are scheduled to be sent.
+	 * <p/>
+	 * Read-only.
+	 */
+	long getNextSendTime(T txn, ContactId c) throws DbException;
+
 	/**
 	 * Returns the message with the given ID, in serialised form, or null if
 	 * the message has been deleted.

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

@@ -10,6 +10,7 @@ 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.Metadata;
+import org.briarproject.bramble.api.db.MigrationListener;
 import org.briarproject.bramble.api.db.NoSuchContactException;
 import org.briarproject.bramble.api.db.NoSuchGroupException;
 import org.briarproject.bramble.api.db.NoSuchLocalAuthorException;
@@ -90,8 +91,6 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	private final ReentrantReadWriteLock lock =
 			new ReentrantReadWriteLock(true);
 
-	private volatile int shutdownHandle = -1;
-
 	@Inject
 	DatabaseComponentImpl(Database<T> db, Class<T> txnClass, EventBus eventBus,
 			ShutdownManager shutdown) {
@@ -102,27 +101,22 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 	}
 
 	@Override
-	public boolean open() throws DbException {
-		Runnable shutdownHook = new Runnable() {
-			@Override
-			public void run() {
-				try {
-					close();
-				} catch (DbException e) {
-					if (LOG.isLoggable(WARNING))
-						LOG.log(WARNING, e.toString(), e);
-				}
+	public boolean open(@Nullable MigrationListener listener)
+			throws DbException {
+		boolean reopened = db.open(listener);
+		shutdown.addShutdownHook(() -> {
+			try {
+				close();
+			} catch (DbException e) {
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			}
-		};
-		boolean reopened = db.open();
-		shutdownHandle = shutdown.addShutdownHook(shutdownHook);
+		});
 		return reopened;
 	}
 
 	@Override
 	public void close() throws DbException {
 		if (closed.getAndSet(true)) return;
-		shutdown.removeShutdownHook(shutdownHandle);
 		db.close();
 	}
 
@@ -141,11 +135,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		}
 		try {
 			return new Transaction(db.startTransaction(), readOnly);
-		} catch (DbException e) {
-			if (readOnly) lock.readLock().unlock();
-			else lock.writeLock().unlock();
-			throw e;
-		} catch (RuntimeException e) {
+		} catch (DbException | RuntimeException e) {
 			if (readOnly) lock.readLock().unlock();
 			else lock.writeLock().unlock();
 			throw e;
@@ -331,7 +321,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		if (!db.containsContact(txn, c))
 			throw new NoSuchContactException();
 		Collection<MessageId> ids = db.getMessagesToSend(txn, c, maxLength);
-		List<byte[]> messages = new ArrayList<byte[]>(ids.size());
+		List<byte[]> messages = new ArrayList<>(ids.size());
 		for (MessageId m : ids) {
 			messages.add(db.getRawMessage(txn, m));
 			db.updateExpiryTime(txn, c, m, maxLatency);
@@ -381,7 +371,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			throw new NoSuchContactException();
 		Collection<MessageId> ids = db.getRequestedMessagesToSend(txn, c,
 				maxLength);
-		List<byte[]> messages = new ArrayList<byte[]>(ids.size());
+		List<byte[]> messages = new ArrayList<>(ids.size());
 		for (MessageId m : ids) {
 			messages.add(db.getRawMessage(txn, m));
 			db.updateExpiryTime(txn, c, m, maxLatency);
@@ -591,6 +581,13 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return db.getMessageDependents(txn, m);
 	}
 
+	@Override
+	public long getNextSendTime(Transaction transaction, ContactId c)
+		throws DbException {
+		T txn = unbox(transaction);
+		return db.getNextSendTime(txn, c);
+	}
+
 	@Override
 	public Settings getSettings(Transaction transaction, String namespace)
 			throws DbException {
@@ -661,7 +658,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		T txn = unbox(transaction);
 		if (!db.containsContact(txn, c))
 			throw new NoSuchContactException();
-		Collection<MessageId> acked = new ArrayList<MessageId>();
+		Collection<MessageId> acked = new ArrayList<>();
 		for (MessageId m : a.getMessageIds()) {
 			if (db.containsVisibleMessage(txn, c, m)) {
 				db.raiseSeenFlag(txn, c, m);
@@ -770,6 +767,16 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		transaction.attach(new LocalAuthorRemovedEvent(a));
 	}
 
+	@Override
+	public void removeMessage(Transaction transaction, MessageId m)
+			throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsMessage(txn, m))
+			throw new NoSuchMessageException();
+		db.removeMessage(txn, m);
+	}
+
 	@Override
 	public void removeTransport(Transaction transaction, TransportId t)
 			throws DbException {
@@ -886,8 +893,7 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			Map<ContactId, TransportKeys> keys) throws DbException {
 		if (transaction.isReadOnly()) throw new IllegalArgumentException();
 		T txn = unbox(transaction);
-		Map<ContactId, TransportKeys> filtered =
-				new HashMap<ContactId, TransportKeys>();
+		Map<ContactId, TransportKeys> filtered = new HashMap<>();
 		for (Entry<ContactId, TransportKeys> e : keys.entrySet()) {
 			ContactId c = e.getKey();
 			TransportKeys k = e.getValue();

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

@@ -23,10 +23,4 @@ interface DatabaseConstants {
 	 */
 	String SCHEMA_VERSION_KEY = "schemaVersion";
 
-	/**
-	 * The {@link Settings} key under which the minimum supported database
-	 * schema version is stored.
-	 */
-	String MIN_SCHEMA_VERSION_KEY = "minSchemaVersion";
-
 }

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

@@ -32,7 +32,7 @@ public class DatabaseExecutorModule {
 
 	public DatabaseExecutorModule() {
 		// Use an unbounded queue
-		BlockingQueue<Runnable> queue = new LinkedBlockingQueue<Runnable>();
+		BlockingQueue<Runnable> queue = new LinkedBlockingQueue<>();
 		// Discard tasks that are submitted during shutdown
 		RejectedExecutionHandler policy =
 				new ThreadPoolExecutor.DiscardPolicy();

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

@@ -26,7 +26,7 @@ public class DatabaseModule {
 	@Singleton
 	DatabaseComponent provideDatabaseComponent(Database<Connection> db,
 			EventBus eventBus, ShutdownManager shutdown) {
-		return new DatabaseComponentImpl<Connection>(db, Connection.class,
-				eventBus, shutdown);
+		return new DatabaseComponentImpl<>(db, Connection.class, eventBus,
+				shutdown);
 	}
 }

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

@@ -3,6 +3,7 @@ package org.briarproject.bramble.db;
 import org.briarproject.bramble.api.crypto.SecretKey;
 import org.briarproject.bramble.api.db.DatabaseConfig;
 import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.db.MigrationListener;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.util.StringUtils;
@@ -13,6 +14,7 @@ import java.sql.DriverManager;
 import java.sql.SQLException;
 import java.util.Properties;
 
+import javax.annotation.Nullable;
 import javax.inject.Inject;
 
 /**
@@ -40,10 +42,11 @@ class H2Database extends JdbcDatabase {
 	}
 
 	@Override
-	public boolean open() throws DbException {
+	public boolean open(@Nullable MigrationListener listener)
+			throws DbException {
 		boolean reopen = config.databaseExists();
 		if (!reopen) config.getDatabaseDirectory().mkdirs();
-		super.open("org.h2.Driver", reopen);
+		super.open("org.h2.Driver", reopen, listener);
 		return reopen;
 	}
 

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

@@ -3,9 +3,12 @@ package org.briarproject.bramble.db;
 import org.briarproject.bramble.api.contact.Contact;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.db.DataTooNewException;
+import org.briarproject.bramble.api.db.DataTooOldException;
 import org.briarproject.bramble.api.db.DbClosedException;
 import org.briarproject.bramble.api.db.DbException;
 import org.briarproject.bramble.api.db.Metadata;
+import org.briarproject.bramble.api.db.MigrationListener;
 import org.briarproject.bramble.api.identity.Author;
 import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.identity.LocalAuthor;
@@ -47,6 +50,7 @@ import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
 
+import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.api.db.Metadata.REMOVE;
 import static org.briarproject.bramble.api.sync.Group.Visibility.INVISIBLE;
@@ -57,7 +61,6 @@ import static org.briarproject.bramble.api.sync.ValidationManager.State.INVALID;
 import static org.briarproject.bramble.api.sync.ValidationManager.State.PENDING;
 import static org.briarproject.bramble.api.sync.ValidationManager.State.UNKNOWN;
 import static org.briarproject.bramble.db.DatabaseConstants.DB_SETTINGS_NAMESPACE;
-import static org.briarproject.bramble.db.DatabaseConstants.MIN_SCHEMA_VERSION_KEY;
 import static org.briarproject.bramble.db.DatabaseConstants.SCHEMA_VERSION_KEY;
 import static org.briarproject.bramble.db.ExponentialBackoff.calculateExpiry;
 
@@ -68,8 +71,8 @@ import static org.briarproject.bramble.db.ExponentialBackoff.calculateExpiry;
 @NotNullByDefault
 abstract class JdbcDatabase implements Database<Connection> {
 
-	private static final int SCHEMA_VERSION = 30;
-	private static final int MIN_SCHEMA_VERSION = 30;
+	// Package access for testing
+	static final int CODE_SCHEMA_VERSION = 31;
 
 	private static final String CREATE_SETTINGS =
 			"CREATE TABLE settings"
@@ -148,11 +151,16 @@ abstract class JdbcDatabase implements Database<Connection> {
 	private static final String CREATE_MESSAGE_METADATA =
 			"CREATE TABLE messageMetadata"
 					+ " (messageId HASH NOT NULL,"
+					+ " groupId HASH NOT NULL," // Denormalised
+					+ " state INT NOT NULL," // Denormalised
 					+ " key VARCHAR NOT NULL,"
 					+ " value BINARY NOT NULL,"
 					+ " PRIMARY KEY (messageId, key),"
 					+ " FOREIGN KEY (messageId)"
 					+ " REFERENCES messages (messageId)"
+					+ " ON DELETE CASCADE,"
+					+ " FOREIGN KEY (groupId)"
+					+ " REFERENCES groups (groupId)"
 					+ " ON DELETE CASCADE)";
 
 	private static final String CREATE_MESSAGE_DEPENDENCIES =
@@ -232,6 +240,18 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " REFERENCES transports (transportId)"
 					+ " ON DELETE CASCADE)";
 
+	private static final String INDEX_CONTACTS_BY_AUTHOR_ID =
+			"CREATE INDEX IF NOT EXISTS contactsByAuthorId"
+					+ " ON contacts (authorId)";
+
+	private static final String INDEX_GROUPS_BY_CLIENT_ID =
+			"CREATE INDEX IF NOT EXISTS groupsByClientId"
+					+ " ON groups (clientId)";
+
+	private static final String INDEX_MESSAGE_METADATA_BY_GROUP_ID_STATE =
+			"CREATE INDEX IF NOT EXISTS messageMetadataByGroupIdState"
+					+ " ON messageMetadata (groupId, state)";
+
 	private static final Logger LOG =
 			Logger.getLogger(JdbcDatabase.class.getName());
 
@@ -239,8 +259,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 	private final String hashType, binaryType, counterType, secretType;
 	private final Clock clock;
 
-	private final LinkedList<Connection> connections =
-			new LinkedList<Connection>(); // Locking: connectionsLock
+	// Locking: connectionsLock
+	private final LinkedList<Connection> connections = new LinkedList<>();
 
 	private int openConnections = 0; // Locking: connectionsLock
 	private boolean closed = false; // Locking: connectionsLock
@@ -260,22 +280,24 @@ abstract class JdbcDatabase implements Database<Connection> {
 		this.clock = clock;
 	}
 
-	protected void open(String driverClass, boolean reopen) throws DbException {
+	protected void open(String driverClass, boolean reopen,
+			@Nullable MigrationListener listener) throws DbException {
 		// Load the JDBC driver
 		try {
 			Class.forName(driverClass);
 		} catch (ClassNotFoundException e) {
 			throw new DbException(e);
 		}
-		// Open the database and create the tables if necessary
+		// Open the database and create the tables and indexes if necessary
 		Connection txn = startTransaction();
 		try {
 			if (reopen) {
-				if (!checkSchemaVersion(txn)) throw new DbException();
+				checkSchemaVersion(txn, listener);
 			} else {
 				createTables(txn);
-				storeSchemaVersion(txn);
+				storeSchemaVersion(txn, CODE_SCHEMA_VERSION);
 			}
+			createIndexes(txn);
 			commitTransaction(txn);
 		} catch (DbException e) {
 			abortTransaction(txn);
@@ -283,19 +305,51 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
-	private boolean checkSchemaVersion(Connection txn) throws DbException {
+	/**
+	 * Compares the schema version stored in the database with the schema
+	 * version used by the current code and applies any suitable migrations to
+	 * the data if necessary.
+	 *
+	 * @throws DataTooNewException if the data uses a newer schema than the
+	 * current code
+	 * @throws DataTooOldException if the data uses an older schema than the
+	 * current code and cannot be migrated
+	 */
+	private void checkSchemaVersion(Connection txn,
+			@Nullable MigrationListener listener) throws DbException {
 		Settings s = getSettings(txn, DB_SETTINGS_NAMESPACE);
-		int schemaVersion = s.getInt(SCHEMA_VERSION_KEY, -1);
-		if (schemaVersion == SCHEMA_VERSION) return true;
-		if (schemaVersion < MIN_SCHEMA_VERSION) return false;
-		int minSchemaVersion = s.getInt(MIN_SCHEMA_VERSION_KEY, -1);
-		return SCHEMA_VERSION >= minSchemaVersion;
+		int dataSchemaVersion = s.getInt(SCHEMA_VERSION_KEY, -1);
+		if (dataSchemaVersion == -1) throw new DbException();
+		if (dataSchemaVersion == CODE_SCHEMA_VERSION) return;
+		if (CODE_SCHEMA_VERSION < dataSchemaVersion)
+			throw new DataTooNewException();
+		// Apply any suitable migrations in order
+		for (Migration<Connection> m : getMigrations()) {
+			int start = m.getStartVersion(), end = m.getEndVersion();
+			if (start == dataSchemaVersion) {
+				if (LOG.isLoggable(INFO))
+					LOG.info("Migrating from schema " + start + " to " + end);
+				if (listener != null) listener.onMigrationRun();
+				// Apply the migration
+				m.migrate(txn);
+				// Store the new schema version
+				storeSchemaVersion(txn, end);
+				dataSchemaVersion = end;
+			}
+		}
+		if (dataSchemaVersion != CODE_SCHEMA_VERSION)
+			throw new DataTooOldException();
 	}
 
-	private void storeSchemaVersion(Connection txn) throws DbException {
+	// Package access for testing
+	List<Migration<Connection>> getMigrations() {
+		return Collections.singletonList(new Migration30_31());
+	}
+
+	private void storeSchemaVersion(Connection txn, int version)
+			throws DbException {
 		Settings s = new Settings();
-		s.putInt(SCHEMA_VERSION_KEY, SCHEMA_VERSION);
-		s.putInt(MIN_SCHEMA_VERSION_KEY, MIN_SCHEMA_VERSION);
+		s.putInt(SCHEMA_VERSION_KEY, version);
 		mergeSettings(txn, s, DB_SETTINGS_NAMESPACE);
 	}
 
@@ -340,6 +394,20 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
+	private void createIndexes(Connection txn) throws DbException {
+		Statement s = null;
+		try {
+			s = txn.createStatement();
+			s.executeUpdate(INDEX_CONTACTS_BY_AUTHOR_ID);
+			s.executeUpdate(INDEX_GROUPS_BY_CLIENT_ID);
+			s.executeUpdate(INDEX_MESSAGE_METADATA_BY_GROUP_ID_STATE);
+			s.close();
+		} catch (SQLException e) {
+			tryToClose(s);
+			throw new DbException(e);
+		}
+	}
+
 	private String insertTypeNames(String s) {
 		s = s.replaceAll("HASH", hashType);
 		s = s.replaceAll("BINARY", binaryType);
@@ -458,7 +526,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 		try {
 			// Create a contact row
 			String sql = "INSERT INTO contacts"
-					+ " (authorId, name, publicKey, localAuthorId, verified, active)"
+					+ " (authorId, name, publicKey, localAuthorId,"
+					+ " verified, active)"
 					+ " VALUES (?, ?, ?, ?, ?, ?)";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, remote.getId().getBytes());
@@ -993,7 +1062,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " FROM contacts";
 			ps = txn.prepareStatement(sql);
 			rs = ps.executeQuery();
-			List<Contact> contacts = new ArrayList<Contact>();
+			List<Contact> contacts = new ArrayList<>();
 			while (rs.next()) {
 				ContactId contactId = new ContactId(rs.getInt(1));
 				AuthorId authorId = new AuthorId(rs.getBytes(2));
@@ -1027,7 +1096,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, local.getBytes());
 			rs = ps.executeQuery();
-			List<ContactId> ids = new ArrayList<ContactId>();
+			List<ContactId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new ContactId(rs.getInt(1)));
 			rs.close();
 			ps.close();
@@ -1052,7 +1121,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, remote.getBytes());
 			rs = ps.executeQuery();
-			List<Contact> contacts = new ArrayList<Contact>();
+			List<Contact> contacts = new ArrayList<>();
 			while (rs.next()) {
 				ContactId c = new ContactId(rs.getInt(1));
 				String name = rs.getString(2);
@@ -1108,7 +1177,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setString(1, c.getString());
 			rs = ps.executeQuery();
-			List<Group> groups = new ArrayList<Group>();
+			List<Group> groups = new ArrayList<>();
 			while (rs.next()) {
 				GroupId id = new GroupId(rs.getBytes(1));
 				byte[] descriptor = rs.getBytes(2);
@@ -1161,7 +1230,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, g.getBytes());
 			rs = ps.executeQuery();
-			List<ContactId> visible = new ArrayList<ContactId>();
+			List<ContactId> visible = new ArrayList<>();
 			while (rs.next()) visible.add(new ContactId(rs.getInt(1)));
 			rs.close();
 			ps.close();
@@ -1213,7 +1282,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " FROM localAuthors";
 			ps = txn.prepareStatement(sql);
 			rs = ps.executeQuery();
-			List<LocalAuthor> authors = new ArrayList<LocalAuthor>();
+			List<LocalAuthor> authors = new ArrayList<>();
 			while (rs.next()) {
 				AuthorId authorId = new AuthorId(rs.getBytes(1));
 				String name = rs.getString(2);
@@ -1243,7 +1312,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, g.getBytes());
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1266,7 +1335,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(1, state.getValue());
 			ps.setBytes(2, g.getBytes());
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1288,20 +1357,17 @@ abstract class JdbcDatabase implements Database<Connection> {
 		try {
 			// Retrieve the message IDs for each query term and intersect
 			Set<MessageId> intersection = null;
-			String sql = "SELECT m.messageId"
-					+ " FROM messages AS m"
-					+ " JOIN messageMetadata AS md"
-					+ " ON m.messageId = md.messageId"
-					+ " WHERE state = ? AND groupId = ?"
+			String sql = "SELECT messageId FROM messageMetadata"
+					+ " WHERE groupId = ? AND state = ?"
 					+ " AND key = ? AND value = ?";
 			for (Entry<String, byte[]> e : query.entrySet()) {
 				ps = txn.prepareStatement(sql);
-				ps.setInt(1, DELIVERED.getValue());
-				ps.setBytes(2, g.getBytes());
+				ps.setBytes(1, g.getBytes());
+				ps.setInt(2, DELIVERED.getValue());
 				ps.setString(3, e.getKey());
 				ps.setBytes(4, e.getValue());
 				rs = ps.executeQuery();
-				Set<MessageId> ids = new HashSet<MessageId>();
+				Set<MessageId> ids = new HashSet<>();
 				while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 				rs.close();
 				ps.close();
@@ -1325,25 +1391,20 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT m.messageId, key, value"
-					+ " FROM messages AS m"
-					+ " JOIN messageMetadata AS md"
-					+ " ON m.messageId = md.messageId"
-					+ " WHERE state = ? AND groupId = ?"
-					+ " ORDER BY m.messageId";
+			String sql = "SELECT messageId, key, value"
+					+ " FROM messageMetadata"
+					+ " WHERE groupId = ? AND state = ?";
 			ps = txn.prepareStatement(sql);
-			ps.setInt(1, DELIVERED.getValue());
-			ps.setBytes(2, g.getBytes());
+			ps.setBytes(1, g.getBytes());
+			ps.setInt(2, DELIVERED.getValue());
 			rs = ps.executeQuery();
-			Map<MessageId, Metadata> all = new HashMap<MessageId, Metadata>();
-			Metadata metadata = null;
-			MessageId lastMessageId = null;
+			Map<MessageId, Metadata> all = new HashMap<>();
 			while (rs.next()) {
 				MessageId messageId = new MessageId(rs.getBytes(1));
-				if (lastMessageId == null || !messageId.equals(lastMessageId)) {
+				Metadata metadata = all.get(messageId);
+				if (metadata == null) {
 					metadata = new Metadata();
 					all.put(messageId, metadata);
-					lastMessageId = messageId;
 				}
 				metadata.put(rs.getString(2), rs.getBytes(3));
 			}
@@ -1364,8 +1425,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 		Collection<MessageId> matches = getMessageIds(txn, g, query);
 		if (matches.isEmpty()) return Collections.emptyMap();
 		// Retrieve the metadata for each match
-		Map<MessageId, Metadata> all = new HashMap<MessageId, Metadata>(
-				matches.size());
+		Map<MessageId, Metadata> all = new HashMap<>(matches.size());
 		for (MessageId m : matches) all.put(m, getMessageMetadata(txn, m));
 		return all;
 	}
@@ -1399,10 +1459,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT key, value FROM messageMetadata AS md"
-					+ " JOIN messages AS m"
-					+ " ON m.messageId = md.messageId"
-					+ " WHERE m.state = ? AND md.messageId = ?";
+			String sql = "SELECT key, value FROM messageMetadata"
+					+ " WHERE state = ? AND messageId = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setInt(1, DELIVERED.getValue());
 			ps.setBytes(2, m.getBytes());
@@ -1425,11 +1483,9 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT key, value FROM messageMetadata AS md"
-					+ " JOIN messages AS m"
-					+ " ON m.messageId = md.messageId"
-					+ " WHERE (m.state = ? OR m.state = ?)"
-					+ " AND md.messageId = ?";
+			String sql = "SELECT key, value FROM messageMetadata"
+					+ " WHERE (state = ? OR state = ?)"
+					+ " AND messageId = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setInt(1, DELIVERED.getValue());
 			ps.setInt(2, PENDING.getValue());
@@ -1463,7 +1519,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setBytes(1, g.getBytes());
 			ps.setInt(2, c.getInt());
 			rs = ps.executeQuery();
-			List<MessageStatus> statuses = new ArrayList<MessageStatus>();
+			List<MessageStatus> statuses = new ArrayList<>();
 			while (rs.next()) {
 				MessageId messageId = new MessageId(rs.getBytes(1));
 				boolean sent = rs.getBoolean(2);
@@ -1522,7 +1578,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, m.getBytes());
 			rs = ps.executeQuery();
-			Map<MessageId, State> dependencies = new HashMap<MessageId, State>();
+			Map<MessageId, State> dependencies = new HashMap<>();
 			while (rs.next()) {
 				MessageId dependency = new MessageId(rs.getBytes(1));
 				State state = State.fromValue(rs.getInt(2));
@@ -1560,7 +1616,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, m.getBytes());
 			rs = ps.executeQuery();
-			Map<MessageId, State> dependents = new HashMap<MessageId, State>();
+			Map<MessageId, State> dependents = new HashMap<>();
 			while (rs.next()) {
 				MessageId dependent = new MessageId(rs.getBytes(1));
 				State state = State.fromValue(rs.getInt(2));
@@ -1612,7 +1668,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(1, c.getInt());
 			ps.setInt(2, maxMessages);
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1648,7 +1704,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setLong(3, now);
 			ps.setInt(4, maxMessages);
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1673,7 +1729,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(1, c.getInt());
 			ps.setInt(2, maxMessages);
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1708,7 +1764,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(2, DELIVERED.getValue());
 			ps.setLong(3, now);
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			int total = 0;
 			while (rs.next()) {
 				int length = rs.getInt(1);
@@ -1750,7 +1806,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(1, state.getValue());
 			ps.setString(2, c.getString());
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1780,7 +1836,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setString(1, c.getString());
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			while (rs.next()) ids.add(new MessageId(rs.getBytes(1)));
 			rs.close();
 			ps.close();
@@ -1792,6 +1848,41 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
+	@Override
+	public long getNextSendTime(Connection txn, ContactId c)
+			throws DbException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT expiry FROM messages AS m"
+					+ " JOIN groupVisibilities AS gv"
+					+ " ON m.groupId = gv.groupId"
+					+ " JOIN statuses AS s"
+					+ " ON m.messageId = s.messageId"
+					+ " AND gv.contactId = s.contactId"
+					+ " WHERE gv.contactId = ? AND gv.shared = TRUE"
+					+ " AND state = ? AND m.shared = TRUE AND raw IS NOT NULL"
+					+ " AND seen = FALSE"
+					+ " ORDER BY expiry LIMIT 1";
+			ps = txn.prepareStatement(sql);
+			ps.setInt(1, c.getInt());
+			ps.setInt(2, DELIVERED.getValue());
+			rs = ps.executeQuery();
+			long nextSendTime = Long.MAX_VALUE;
+			if (rs.next()) {
+				nextSendTime = rs.getLong(1);
+				if (rs.next()) throw new AssertionError();
+			}
+			rs.close();
+			ps.close();
+			return nextSendTime;
+		} catch (SQLException e) {
+			tryToClose(rs);
+			tryToClose(ps);
+			throw new DbException(e);
+		}
+	}
+
 	@Override
 	@Nullable
 	public byte[] getRawMessage(Connection txn, MessageId m)
@@ -1839,7 +1930,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.setInt(2, DELIVERED.getValue());
 			ps.setLong(3, now);
 			rs = ps.executeQuery();
-			List<MessageId> ids = new ArrayList<MessageId>();
+			List<MessageId> ids = new ArrayList<>();
 			int total = 0;
 			while (rs.next()) {
 				int length = rs.getInt(1);
@@ -1893,7 +1984,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setString(1, t.getString());
 			rs = ps.executeQuery();
-			List<IncomingKeys> inKeys = new ArrayList<IncomingKeys>();
+			List<IncomingKeys> inKeys = new ArrayList<>();
 			while (rs.next()) {
 				long rotationPeriod = rs.getLong(1);
 				SecretKey tagKey = new SecretKey(rs.getBytes(2));
@@ -1913,8 +2004,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps = txn.prepareStatement(sql);
 			ps.setString(1, t.getString());
 			rs = ps.executeQuery();
-			Map<ContactId, TransportKeys> keys =
-					new HashMap<ContactId, TransportKeys>();
+			Map<ContactId, TransportKeys> keys = new HashMap<>();
 			for (int i = 0; rs.next(); i++) {
 				// There should be three times as many incoming keys
 				if (inKeys.size() < (i + 1) * 3) throw new DbStateException();
@@ -2004,7 +2094,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 			int[] batchAffected = ps.executeBatch();
 			if (batchAffected.length != requested.size())
 				throw new DbStateException();
-			for (int rows: batchAffected) {
+			for (int rows : batchAffected) {
 				if (rows < 0) throw new DbStateException();
 				if (rows > 1) throw new DbStateException();
 			}
@@ -2018,25 +2108,92 @@ abstract class JdbcDatabase implements Database<Connection> {
 	@Override
 	public void mergeGroupMetadata(Connection txn, GroupId g, Metadata meta)
 			throws DbException {
-		mergeMetadata(txn, g.getBytes(), meta, "groupMetadata", "groupId");
+		PreparedStatement ps = null;
+		try {
+			Map<String, byte[]> added = removeOrUpdateMetadata(txn,
+					g.getBytes(), meta, "groupMetadata", "groupId");
+			if (added.isEmpty()) return;
+			// Insert any keys that don't already exist
+			String sql = "INSERT INTO groupMetadata (groupId, key, value)"
+					+ " VALUES (?, ?, ?)";
+			ps = txn.prepareStatement(sql);
+			ps.setBytes(1, g.getBytes());
+			for (Entry<String, byte[]> e : added.entrySet()) {
+				ps.setString(2, e.getKey());
+				ps.setBytes(3, e.getValue());
+				ps.addBatch();
+			}
+			int[] batchAffected = ps.executeBatch();
+			if (batchAffected.length != added.size())
+				throw new DbStateException();
+			for (int rows : batchAffected)
+				if (rows != 1) throw new DbStateException();
+			ps.close();
+		} catch (SQLException e) {
+			tryToClose(ps);
+			throw new DbException(e);
+		}
 	}
 
 	@Override
-	public void mergeMessageMetadata(Connection txn, MessageId m, Metadata meta)
-			throws DbException {
-		mergeMetadata(txn, m.getBytes(), meta, "messageMetadata", "messageId");
+	public void mergeMessageMetadata(Connection txn, MessageId m,
+			Metadata meta) throws DbException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			Map<String, byte[]> added = removeOrUpdateMetadata(txn,
+					m.getBytes(), meta, "messageMetadata", "messageId");
+			if (added.isEmpty()) return;
+			// Get the group ID and message state for the denormalised columns
+			String sql = "SELECT groupId, state FROM messages"
+					+ " WHERE messageId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setBytes(1, m.getBytes());
+			rs = ps.executeQuery();
+			if (!rs.next()) throw new DbStateException();
+			GroupId g = new GroupId(rs.getBytes(1));
+			State state = State.fromValue(rs.getInt(2));
+			rs.close();
+			ps.close();
+			// Insert any keys that don't already exist
+			sql = "INSERT INTO messageMetadata"
+					+ " (messageId, groupId, state, key, value)"
+					+ " VALUES (?, ?, ?, ?, ?)";
+			ps = txn.prepareStatement(sql);
+			ps.setBytes(1, m.getBytes());
+			ps.setBytes(2, g.getBytes());
+			ps.setInt(3, state.getValue());
+			for (Entry<String, byte[]> e : added.entrySet()) {
+				ps.setString(4, e.getKey());
+				ps.setBytes(5, e.getValue());
+				ps.addBatch();
+			}
+			int[] batchAffected = ps.executeBatch();
+			if (batchAffected.length != added.size())
+				throw new DbStateException();
+			for (int rows : batchAffected)
+				if (rows != 1) throw new DbStateException();
+			ps.close();
+		} catch (SQLException e) {
+			tryToClose(rs);
+			tryToClose(ps);
+			throw new DbException(e);
+		}
 	}
 
-	private void mergeMetadata(Connection txn, byte[] id, Metadata meta,
-			String tableName, String columnName) throws DbException {
+	// Removes or updates any existing entries, returns any entries that
+	// need to be added
+	private Map<String, byte[]> removeOrUpdateMetadata(Connection txn,
+			byte[] id, Metadata meta, String tableName, String columnName)
+			throws DbException {
 		PreparedStatement ps = null;
 		try {
 			// Determine which keys are being removed
-			List<String> removed = new ArrayList<String>();
-			Map<String, byte[]> retained = new HashMap<String, byte[]>();
+			List<String> removed = new ArrayList<>();
+			Map<String, byte[]> notRemoved = new HashMap<>();
 			for (Entry<String, byte[]> e : meta.entrySet()) {
 				if (e.getValue() == REMOVE) removed.add(e.getKey());
-				else retained.put(e.getKey(), e.getValue());
+				else notRemoved.put(e.getKey(), e.getValue());
 			}
 			// Delete any keys that are being removed
 			if (!removed.isEmpty()) {
@@ -2057,45 +2214,33 @@ abstract class JdbcDatabase implements Database<Connection> {
 				}
 				ps.close();
 			}
-			if (retained.isEmpty()) return;
+			if (notRemoved.isEmpty()) return Collections.emptyMap();
 			// Update any keys that already exist
 			String sql = "UPDATE " + tableName + " SET value = ?"
 					+ " WHERE " + columnName + " = ? AND key = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(2, id);
-			for (Entry<String, byte[]> e : retained.entrySet()) {
+			for (Entry<String, byte[]> e : notRemoved.entrySet()) {
 				ps.setBytes(1, e.getValue());
 				ps.setString(3, e.getKey());
 				ps.addBatch();
 			}
 			int[] batchAffected = ps.executeBatch();
-			if (batchAffected.length != retained.size())
+			if (batchAffected.length != notRemoved.size())
 				throw new DbStateException();
 			for (int rows : batchAffected) {
 				if (rows < 0) throw new DbStateException();
 				if (rows > 1) throw new DbStateException();
 			}
-			// Insert any keys that don't already exist
-			sql = "INSERT INTO " + tableName
-					+ " (" + columnName + ", key, value)"
-					+ " VALUES (?, ?, ?)";
-			ps = txn.prepareStatement(sql);
-			ps.setBytes(1, id);
-			int updateIndex = 0, inserted = 0;
-			for (Entry<String, byte[]> e : retained.entrySet()) {
-				if (batchAffected[updateIndex] == 0) {
-					ps.setString(2, e.getKey());
-					ps.setBytes(3, e.getValue());
-					ps.addBatch();
-					inserted++;
-				}
-				updateIndex++;
-			}
-			batchAffected = ps.executeBatch();
-			if (batchAffected.length != inserted) throw new DbStateException();
-			for (int rows : batchAffected)
-				if (rows != 1) throw new DbStateException();
 			ps.close();
+			// Are there any keys that don't already exist?
+			Map<String, byte[]> added = new HashMap<>();
+			int updateIndex = 0;
+			for (Entry<String, byte[]> e : notRemoved.entrySet()) {
+				if (batchAffected[updateIndex++] == 0)
+					added.put(e.getKey(), e.getValue());
+			}
+			return added;
 		} catch (SQLException e) {
 			tryToClose(ps);
 			throw new DbException(e);
@@ -2448,7 +2593,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	@Override
-	public void setMessageShared(Connection txn, MessageId m) throws DbException {
+	public void setMessageShared(Connection txn, MessageId m)
+			throws DbException {
 		PreparedStatement ps = null;
 		try {
 			String sql = "UPDATE messages SET shared = TRUE"
@@ -2476,6 +2622,14 @@ abstract class JdbcDatabase implements Database<Connection> {
 			int affected = ps.executeUpdate();
 			if (affected < 0 || affected > 1) throw new DbStateException();
 			ps.close();
+			// Update denormalised column in messageMetadata
+			sql = "UPDATE messageMetadata SET state = ? WHERE messageId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setInt(1, state.getValue());
+			ps.setBytes(2, m.getBytes());
+			affected = ps.executeUpdate();
+			if (affected < 0) throw new DbStateException();
+			ps.close();
 		} catch (SQLException e) {
 			tryToClose(ps);
 			throw new DbException(e);

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

@@ -0,0 +1,18 @@
+package org.briarproject.bramble.db;
+
+import org.briarproject.bramble.api.db.DbException;
+
+interface Migration<T> {
+
+	/**
+	 * Returns the schema version from which this migration starts.
+	 */
+	int getStartVersion();
+
+	/**
+	 * Returns the schema version at which this migration ends.
+	 */
+	int getEndVersion();
+
+	void migrate(T txn) throws DbException;
+}

bramble-core/src/main/java/org/briarproject/bramble/db/Migration30_31.java

@@ -0,0 +1,75 @@
+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 javax.annotation.Nullable;
+
+import static java.util.logging.Level.WARNING;
+
+class Migration30_31 implements Migration<Connection> {
+
+	private static final Logger LOG =
+			Logger.getLogger(Migration30_31.class.getName());
+
+	@Override
+	public int getStartVersion() {
+		return 30;
+	}
+
+	@Override
+	public int getEndVersion() {
+		return 31;
+	}
+
+	@Override
+	public void migrate(Connection txn) throws DbException {
+		Statement s = null;
+		try {
+			s = txn.createStatement();
+			// Add groupId column
+			s.execute("ALTER TABLE messageMetadata"
+					+ " ADD COLUMN groupId BINARY(32) AFTER messageId");
+			// Populate groupId column
+			s.execute("UPDATE messageMetadata AS mm SET groupId ="
+					+ " (SELECT groupId FROM messages AS m"
+					+ " WHERE mm.messageId = m.messageId)");
+			// Add not null constraint now column has been populated
+			s.execute("ALTER TABLE messageMetadata"
+					+ " ALTER COLUMN groupId"
+					+ " SET NOT NULL");
+			// Add foreign key constraint
+			s.execute("ALTER TABLE messageMetadata"
+					+ " ADD CONSTRAINT groupIdForeignKey"
+					+ " FOREIGN KEY (groupId)"
+					+ " REFERENCES groups (groupId)"
+					+ " ON DELETE CASCADE");
+			// Add state column
+			s.execute("ALTER TABLE messageMetadata"
+					+ " ADD COLUMN state INT AFTER groupId");
+			// Populate state column
+			s.execute("UPDATE messageMetadata AS mm SET state ="
+					+ " (SELECT state FROM messages AS m"
+					+ " WHERE mm.messageId = m.messageId)");
+			// Add not null constraint now column has been populated
+			s.execute("ALTER TABLE messageMetadata"
+					+ " ALTER COLUMN state"
+					+ " SET NOT NULL");
+		} catch (SQLException e) {
+			tryToClose(s);
+			throw new DbException(e);
+		}
+	}
+
+	private void tryToClose(@Nullable Statement s) {
+		try {
+			if (s != null) s.close();
+		} catch (SQLException e) {
+			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+		}
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/event/EventBusImpl.java

@@ -15,7 +15,7 @@ import javax.annotation.concurrent.ThreadSafe;
 class EventBusImpl implements EventBus {
 
 	private final Collection<EventListener> listeners =
-			new CopyOnWriteArrayList<EventListener>();
+			new CopyOnWriteArrayList<>();
 
 	@Override
 	public void addListener(EventListener l) {

bramble-core/src/main/java/org/briarproject/bramble/invitation/AliceConnector.java

@@ -1,119 +0,0 @@
-package org.briarproject.bramble.invitation;
-
-import org.briarproject.bramble.api.contact.ContactExchangeTask;
-import org.briarproject.bramble.api.crypto.CryptoComponent;
-import org.briarproject.bramble.api.crypto.PseudoRandom;
-import org.briarproject.bramble.api.crypto.SecretKey;
-import org.briarproject.bramble.api.data.BdfReader;
-import org.briarproject.bramble.api.data.BdfReaderFactory;
-import org.briarproject.bramble.api.data.BdfWriter;
-import org.briarproject.bramble.api.data.BdfWriterFactory;
-import org.briarproject.bramble.api.identity.LocalAuthor;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
-import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
-import java.security.GeneralSecurityException;
-import java.util.logging.Logger;
-
-import static java.util.logging.Level.INFO;
-import static java.util.logging.Level.WARNING;
-
-/**
- * A connection thread for the peer being Alice in the invitation protocol.
- */
-@NotNullByDefault
-class AliceConnector extends Connector {
-
-	private static final Logger LOG =
-			Logger.getLogger(AliceConnector.class.getName());
-
-	AliceConnector(CryptoComponent crypto, BdfReaderFactory bdfReaderFactory,
-			BdfWriterFactory bdfWriterFactory,
-			ContactExchangeTask contactExchangeTask, ConnectorGroup group,
-			DuplexPlugin plugin, LocalAuthor localAuthor, PseudoRandom random) {
-		super(crypto, bdfReaderFactory, bdfWriterFactory, contactExchangeTask,
-				group, plugin, localAuthor, random);
-	}
-
-	@Override
-	public void run() {
-		// Create an incoming or outgoing connection
-		DuplexTransportConnection conn = createInvitationConnection(true);
-		if (conn == null) return;
-		if (LOG.isLoggable(INFO)) LOG.info(pluginName + " connected");
-		// Don't proceed with more than one connection
-		if (group.getAndSetConnected()) {
-			if (LOG.isLoggable(INFO)) LOG.info(pluginName + " redundant");
-			tryToClose(conn, false);
-			return;
-		}
-		// Carry out the key agreement protocol
-		InputStream in;
-		OutputStream out;
-		BdfReader r;
-		BdfWriter w;
-		SecretKey master;
-		try {
-			in = conn.getReader().getInputStream();
-			out = conn.getWriter().getOutputStream();
-			r = bdfReaderFactory.createReader(in);
-			w = bdfWriterFactory.createWriter(out);
-			// Alice goes first
-			sendPublicKeyHash(w);
-			byte[] hash = receivePublicKeyHash(r);
-			sendPublicKey(w);
-			byte[] key = receivePublicKey(r);
-			master = deriveMasterSecret(hash, key, true);
-		} catch (IOException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			group.keyAgreementFailed();
-			tryToClose(conn, true);
-			return;
-		} catch (GeneralSecurityException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			group.keyAgreementFailed();
-			tryToClose(conn, true);
-			return;
-		}
-		// The key agreement succeeded - derive the confirmation codes
-		if (LOG.isLoggable(INFO)) LOG.info(pluginName + " agreement succeeded");
-		int aliceCode = crypto.deriveBTConfirmationCode(master, true);
-		int bobCode = crypto.deriveBTConfirmationCode(master, false);
-		group.keyAgreementSucceeded(aliceCode, bobCode);
-		// Exchange confirmation results
-		boolean localMatched, remoteMatched;
-		try {
-			localMatched = group.waitForLocalConfirmationResult();
-			sendConfirmation(w, localMatched);
-			remoteMatched = receiveConfirmation(r);
-		} catch (IOException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			group.remoteConfirmationFailed();
-			tryToClose(conn, true);
-			return;
-		} catch (InterruptedException e) {
-			LOG.warning("Interrupted while waiting for confirmation");
-			group.remoteConfirmationFailed();
-			tryToClose(conn, true);
-			Thread.currentThread().interrupt();
-			return;
-		}
-		if (remoteMatched) group.remoteConfirmationSucceeded();
-		else group.remoteConfirmationFailed();
-		if (!(localMatched && remoteMatched)) {
-			if (LOG.isLoggable(INFO))
-				LOG.info(pluginName + " confirmation failed");
-			tryToClose(conn, false);
-			return;
-		}
-		// Confirmation succeeded - upgrade to a secure connection
-		if (LOG.isLoggable(INFO))
-			LOG.info(pluginName + " confirmation succeeded");
-		contactExchangeTask.startExchange(group, localAuthor, master, conn,
-				plugin.getId(), true);
-	}
-}

bramble-core/src/main/java/org/briarproject/bramble/invitation/BobConnector.java

@@ -1,119 +0,0 @@
-package org.briarproject.bramble.invitation;
-
-import org.briarproject.bramble.api.contact.ContactExchangeTask;
-import org.briarproject.bramble.api.crypto.CryptoComponent;
-import org.briarproject.bramble.api.crypto.PseudoRandom;
-import org.briarproject.bramble.api.crypto.SecretKey;
-import org.briarproject.bramble.api.data.BdfReader;
-import org.briarproject.bramble.api.data.BdfReaderFactory;
-import org.briarproject.bramble.api.data.BdfWriter;
-import org.briarproject.bramble.api.data.BdfWriterFactory;
-import org.briarproject.bramble.api.identity.LocalAuthor;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
-import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
-import java.security.GeneralSecurityException;
-import java.util.logging.Logger;
-
-import static java.util.logging.Level.INFO;
-import static java.util.logging.Level.WARNING;
-
-/**
- * A connection thread for the peer being Bob in the invitation protocol.
- */
-@NotNullByDefault
-class BobConnector extends Connector {
-
-	private static final Logger LOG =
-			Logger.getLogger(BobConnector.class.getName());
-
-	BobConnector(CryptoComponent crypto, BdfReaderFactory bdfReaderFactory,
-			BdfWriterFactory bdfWriterFactory,
-			ContactExchangeTask contactExchangeTask, ConnectorGroup group,
-			DuplexPlugin plugin, LocalAuthor localAuthor, PseudoRandom random) {
-		super(crypto, bdfReaderFactory, bdfWriterFactory, contactExchangeTask,
-				group, plugin, localAuthor, random);
-	}
-
-	@Override
-	public void run() {
-		// Create an incoming or outgoing connection
-		DuplexTransportConnection conn = createInvitationConnection(false);
-		if (conn == null) return;
-		if (LOG.isLoggable(INFO)) LOG.info(pluginName + " connected");
-		// Carry out the key agreement protocol
-		InputStream in;
-		OutputStream out;
-		BdfReader r;
-		BdfWriter w;
-		SecretKey master;
-		try {
-			in = conn.getReader().getInputStream();
-			out = conn.getWriter().getOutputStream();
-			r = bdfReaderFactory.createReader(in);
-			w = bdfWriterFactory.createWriter(out);
-			// Alice goes first
-			byte[] hash = receivePublicKeyHash(r);
-			// Don't proceed with more than one connection
-			if (group.getAndSetConnected()) {
-				if (LOG.isLoggable(INFO)) LOG.info(pluginName + " redundant");
-				tryToClose(conn, false);
-				return;
-			}
-			sendPublicKeyHash(w);
-			byte[] key = receivePublicKey(r);
-			sendPublicKey(w);
-			master = deriveMasterSecret(hash, key, false);
-		} catch (IOException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			group.keyAgreementFailed();
-			tryToClose(conn, true);
-			return;
-		} catch (GeneralSecurityException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			group.keyAgreementFailed();
-			tryToClose(conn, true);
-			return;
-		}
-		// The key agreement succeeded - derive the confirmation codes
-		if (LOG.isLoggable(INFO)) LOG.info(pluginName + " agreement succeeded");
-		int aliceCode = crypto.deriveBTConfirmationCode(master, true);
-		int bobCode = crypto.deriveBTConfirmationCode(master, false);
-		group.keyAgreementSucceeded(bobCode, aliceCode);
-		// Exchange confirmation results
-		boolean localMatched, remoteMatched;
-		try {
-			remoteMatched = receiveConfirmation(r);
-			localMatched = group.waitForLocalConfirmationResult();
-			sendConfirmation(w, localMatched);
-		} catch (IOException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			group.remoteConfirmationFailed();
-			tryToClose(conn, true);
-			return;
-		} catch (InterruptedException e) {
-			LOG.warning("Interrupted while waiting for confirmation");
-			group.remoteConfirmationFailed();
-			tryToClose(conn, true);
-			Thread.currentThread().interrupt();
-			return;
-		}
-		if (remoteMatched) group.remoteConfirmationSucceeded();
-		else group.remoteConfirmationFailed();
-		if (!(localMatched && remoteMatched)) {
-			if (LOG.isLoggable(INFO))
-				LOG.info(pluginName + " confirmation failed");
-			tryToClose(conn, false);
-			return;
-		}
-		// Confirmation succeeded - upgrade to a secure connection
-		if (LOG.isLoggable(INFO))
-			LOG.info(pluginName + " confirmation succeeded");
-		contactExchangeTask.startExchange(group, localAuthor, master, conn,
-				plugin.getId(), false);
-	}
-}

bramble-core/src/main/java/org/briarproject/bramble/invitation/Connector.java

@@ -1,150 +0,0 @@
-package org.briarproject.bramble.invitation;
-
-import org.briarproject.bramble.api.FormatException;
-import org.briarproject.bramble.api.contact.ContactExchangeTask;
-import org.briarproject.bramble.api.crypto.CryptoComponent;
-import org.briarproject.bramble.api.crypto.KeyPair;
-import org.briarproject.bramble.api.crypto.KeyParser;
-import org.briarproject.bramble.api.crypto.PseudoRandom;
-import org.briarproject.bramble.api.crypto.SecretKey;
-import org.briarproject.bramble.api.data.BdfReader;
-import org.briarproject.bramble.api.data.BdfReaderFactory;
-import org.briarproject.bramble.api.data.BdfWriter;
-import org.briarproject.bramble.api.data.BdfWriterFactory;
-import org.briarproject.bramble.api.identity.LocalAuthor;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
-import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-
-import java.io.IOException;
-import java.security.GeneralSecurityException;
-import java.util.Arrays;
-import java.util.logging.Logger;
-
-import javax.annotation.Nullable;
-
-import static java.util.logging.Level.INFO;
-import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.api.identity.AuthorConstants.MAX_PUBLIC_KEY_LENGTH;
-import static org.briarproject.bramble.api.invitation.InvitationConstants.CONNECTION_TIMEOUT;
-
-// FIXME: This class has way too many dependencies
-@NotNullByDefault
-abstract class Connector extends Thread {
-
-	private static final Logger LOG =
-			Logger.getLogger(Connector.class.getName());
-	private static final String LABEL_PUBLIC_KEY =
-			"org.briarproject.bramble.invitation.PUBLIC_KEY";
-
-	protected final CryptoComponent crypto;
-	protected final BdfReaderFactory bdfReaderFactory;
-	protected final BdfWriterFactory bdfWriterFactory;
-	protected final ContactExchangeTask contactExchangeTask;
-	protected final ConnectorGroup group;
-	protected final DuplexPlugin plugin;
-	protected final LocalAuthor localAuthor;
-	protected final PseudoRandom random;
-	protected final String pluginName;
-
-	private final KeyPair keyPair;
-	private final KeyParser keyParser;
-
-	Connector(CryptoComponent crypto, BdfReaderFactory bdfReaderFactory,
-			BdfWriterFactory bdfWriterFactory,
-			ContactExchangeTask contactExchangeTask, ConnectorGroup group,
-			DuplexPlugin plugin, LocalAuthor localAuthor, PseudoRandom random) {
-		super("Connector");
-		this.crypto = crypto;
-		this.bdfReaderFactory = bdfReaderFactory;
-		this.bdfWriterFactory = bdfWriterFactory;
-		this.contactExchangeTask = contactExchangeTask;
-		this.group = group;
-		this.plugin = plugin;
-		this.localAuthor = localAuthor;
-		this.random = random;
-		pluginName = plugin.getClass().getName();
-		keyPair = crypto.generateAgreementKeyPair();
-		keyParser = crypto.getAgreementKeyParser();
-	}
-
-	@Nullable
-	DuplexTransportConnection createInvitationConnection(boolean alice) {
-		if (LOG.isLoggable(INFO))
-			LOG.info(pluginName + " creating invitation connection");
-		return plugin.createInvitationConnection(random, CONNECTION_TIMEOUT,
-				alice);
-	}
-
-	void sendPublicKeyHash(BdfWriter w) throws IOException {
-		byte[] hash =
-				crypto.hash(LABEL_PUBLIC_KEY, keyPair.getPublic().getEncoded());
-		w.writeRaw(hash);
-		w.flush();
-		if (LOG.isLoggable(INFO)) LOG.info(pluginName + " sent hash");
-	}
-
-	byte[] receivePublicKeyHash(BdfReader r) throws IOException {
-		int hashLength = crypto.getHashLength();
-		byte[] b = r.readRaw(hashLength);
-		if (b.length < hashLength) throw new FormatException();
-		if (LOG.isLoggable(INFO)) LOG.info(pluginName + " received hash");
-		return b;
-	}
-
-	void sendPublicKey(BdfWriter w) throws IOException {
-		byte[] key = keyPair.getPublic().getEncoded();
-		w.writeRaw(key);
-		w.flush();
-		if (LOG.isLoggable(INFO)) LOG.info(pluginName + " sent key");
-	}
-
-	byte[] receivePublicKey(BdfReader r)
-			throws GeneralSecurityException, IOException {
-		byte[] b = r.readRaw(MAX_PUBLIC_KEY_LENGTH);
-		keyParser.parsePublicKey(b);
-		if (LOG.isLoggable(INFO)) LOG.info(pluginName + " received key");
-		return b;
-	}
-
-	SecretKey deriveMasterSecret(byte[] hash, byte[] key, boolean alice)
-			throws GeneralSecurityException {
-		// Check that the hash matches the key
-		byte[] keyHash =
-				crypto.hash(LABEL_PUBLIC_KEY, keyPair.getPublic().getEncoded());
-		if (!Arrays.equals(hash, keyHash)) {
-			if (LOG.isLoggable(INFO))
-				LOG.info(pluginName + " hash does not match key");
-			throw new GeneralSecurityException();
-		}
-		//  Derive the master secret
-		if (LOG.isLoggable(INFO))
-			LOG.info(pluginName + " deriving master secret");
-		return crypto.deriveMasterSecret(key, keyPair, alice);
-	}
-
-	void sendConfirmation(BdfWriter w, boolean confirmed) throws IOException {
-		w.writeBoolean(confirmed);
-		w.flush();
-		if (LOG.isLoggable(INFO))
-			LOG.info(pluginName + " sent confirmation: " + confirmed);
-	}
-
-	boolean receiveConfirmation(BdfReader r) throws IOException {
-		boolean confirmed = r.readBoolean();
-		if (LOG.isLoggable(INFO))
-			LOG.info(pluginName + " received confirmation: " + confirmed);
-		return confirmed;
-	}
-
-	protected void tryToClose(DuplexTransportConnection conn,
-			boolean exception) {
-		try {
-			LOG.info("Closing connection");
-			conn.getReader().dispose(exception, true);
-			conn.getWriter().dispose(exception);
-		} catch (IOException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		}
-	}
-}

bramble-core/src/main/java/org/briarproject/bramble/invitation/ConnectorGroup.java

@@ -1,278 +0,0 @@
-package org.briarproject.bramble.invitation;
-
-import org.briarproject.bramble.api.contact.ContactExchangeListener;
-import org.briarproject.bramble.api.contact.ContactExchangeTask;
-import org.briarproject.bramble.api.crypto.CryptoComponent;
-import org.briarproject.bramble.api.crypto.PseudoRandom;
-import org.briarproject.bramble.api.data.BdfReaderFactory;
-import org.briarproject.bramble.api.data.BdfWriterFactory;
-import org.briarproject.bramble.api.db.DbException;
-import org.briarproject.bramble.api.identity.Author;
-import org.briarproject.bramble.api.identity.IdentityManager;
-import org.briarproject.bramble.api.identity.LocalAuthor;
-import org.briarproject.bramble.api.invitation.InvitationListener;
-import org.briarproject.bramble.api.invitation.InvitationState;
-import org.briarproject.bramble.api.invitation.InvitationTask;
-import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
-import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
-import org.briarproject.bramble.api.plugin.PluginManager;
-import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
-
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.concurrent.CopyOnWriteArrayList;
-import java.util.concurrent.CountDownLatch;
-import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.concurrent.locks.Lock;
-import java.util.concurrent.locks.ReentrantLock;
-import java.util.logging.Logger;
-
-import static java.util.concurrent.TimeUnit.MILLISECONDS;
-import static java.util.logging.Level.WARNING;
-import static org.briarproject.bramble.api.invitation.InvitationConstants.CONFIRMATION_TIMEOUT;
-
-/**
- * A task consisting of one or more parallel connection attempts.
- */
-@MethodsNotNullByDefault
-@ParametersNotNullByDefault
-class ConnectorGroup extends Thread implements InvitationTask,
-		ContactExchangeListener {
-
-	private static final Logger LOG =
-			Logger.getLogger(ConnectorGroup.class.getName());
-
-	private final CryptoComponent crypto;
-	private final BdfReaderFactory bdfReaderFactory;
-	private final BdfWriterFactory bdfWriterFactory;
-	private final ContactExchangeTask contactExchangeTask;
-	private final IdentityManager identityManager;
-	private final PluginManager pluginManager;
-	private final int localInvitationCode, remoteInvitationCode;
-	private final Collection<InvitationListener> listeners;
-	private final AtomicBoolean connected;
-	private final CountDownLatch localConfirmationLatch;
-	private final Lock lock = new ReentrantLock();
-
-	// The following are locking: lock
-	private int localConfirmationCode = -1, remoteConfirmationCode = -1;
-	private boolean connectionFailed = false;
-	private boolean localCompared = false, remoteCompared = false;
-	private boolean localMatched = false, remoteMatched = false;
-	private String remoteName = null;
-
-	ConnectorGroup(CryptoComponent crypto, BdfReaderFactory bdfReaderFactory,
-			BdfWriterFactory bdfWriterFactory,
-			ContactExchangeTask contactExchangeTask,
-			IdentityManager identityManager, PluginManager pluginManager,
-			int localInvitationCode, int remoteInvitationCode) {
-		super("ConnectorGroup");
-		this.crypto = crypto;
-		this.bdfReaderFactory = bdfReaderFactory;
-		this.bdfWriterFactory = bdfWriterFactory;
-		this.contactExchangeTask = contactExchangeTask;
-		this.identityManager = identityManager;
-		this.pluginManager = pluginManager;
-		this.localInvitationCode = localInvitationCode;
-		this.remoteInvitationCode = remoteInvitationCode;
-		listeners = new CopyOnWriteArrayList<InvitationListener>();
-		connected = new AtomicBoolean(false);
-		localConfirmationLatch = new CountDownLatch(1);
-	}
-
-	@Override
-	public InvitationState addListener(InvitationListener l) {
-		lock.lock();
-		try {
-			listeners.add(l);
-			return new InvitationState(localInvitationCode,
-					remoteInvitationCode, localConfirmationCode,
-					remoteConfirmationCode, connected.get(), connectionFailed,
-					localCompared, remoteCompared, localMatched, remoteMatched,
-					remoteName);
-		} finally {
-			lock.unlock();
-		}
-	}
-
-	@Override
-	public void removeListener(InvitationListener l) {
-		listeners.remove(l);
-	}
-
-	@Override
-	public void connect() {
-		start();
-	}
-
-	@Override
-	public void run() {
-		LocalAuthor localAuthor;
-		// Load the local pseudonym
-		try {
-			localAuthor = identityManager.getLocalAuthor();
-		} catch (DbException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			lock.lock();
-			try {
-				connectionFailed = true;
-			} finally {
-				lock.unlock();
-			}
-			for (InvitationListener l : listeners) l.connectionFailed();
-			return;
-		}
-		// Start the connection threads
-		Collection<Connector> connectors = new ArrayList<Connector>();
-		// Alice is the party with the smaller invitation code
-		if (localInvitationCode < remoteInvitationCode) {
-			for (DuplexPlugin plugin : pluginManager.getInvitationPlugins()) {
-				Connector c = createAliceConnector(plugin, localAuthor);
-				connectors.add(c);
-				c.start();
-			}
-		} else {
-			for (DuplexPlugin plugin : pluginManager.getInvitationPlugins()) {
-				Connector c = createBobConnector(plugin, localAuthor);
-				connectors.add(c);
-				c.start();
-			}
-		}
-		// Wait for the connection threads to finish
-		try {
-			for (Connector c : connectors) c.join();
-		} catch (InterruptedException e) {
-			LOG.warning("Interrupted while waiting for connectors");
-			Thread.currentThread().interrupt();
-		}
-		// If none of the threads connected, inform the listeners
-		if (!connected.get()) {
-			lock.lock();
-			try {
-				connectionFailed = true;
-			} finally {
-				lock.unlock();
-			}
-			for (InvitationListener l : listeners) l.connectionFailed();
-		}
-	}
-
-	private Connector createAliceConnector(DuplexPlugin plugin,
-			LocalAuthor localAuthor) {
-		PseudoRandom random = crypto.getPseudoRandom(localInvitationCode,
-				remoteInvitationCode);
-		return new AliceConnector(crypto, bdfReaderFactory, bdfWriterFactory,
-				contactExchangeTask, this, plugin, localAuthor, random);
-	}
-
-	private Connector createBobConnector(DuplexPlugin plugin,
-			LocalAuthor localAuthor) {
-		PseudoRandom random = crypto.getPseudoRandom(remoteInvitationCode,
-				localInvitationCode);
-		return new BobConnector(crypto, bdfReaderFactory, bdfWriterFactory,
-				contactExchangeTask, this, plugin, localAuthor, random);
-	}
-
-	@Override
-	public void localConfirmationSucceeded() {
-		lock.lock();
-		try {
-			localCompared = true;
-			localMatched = true;
-		} finally {
-			lock.unlock();
-		}
-		localConfirmationLatch.countDown();
-	}
-
-	@Override
-	public void localConfirmationFailed() {
-		lock.lock();
-		try {
-			localCompared = true;
-			localMatched = false;
-		} finally {
-			lock.unlock();
-		}
-		localConfirmationLatch.countDown();
-	}
-
-	boolean getAndSetConnected() {
-		boolean redundant = connected.getAndSet(true);
-		if (!redundant)
-			for (InvitationListener l : listeners) l.connectionSucceeded();
-		return redundant;
-	}
-
-	void keyAgreementSucceeded(int localCode, int remoteCode) {
-		lock.lock();
-		try {
-			localConfirmationCode = localCode;
-			remoteConfirmationCode = remoteCode;
-		} finally {
-			lock.unlock();
-		}
-		for (InvitationListener l : listeners)
-			l.keyAgreementSucceeded(localCode, remoteCode);
-	}
-
-	void keyAgreementFailed() {
-		for (InvitationListener l : listeners) l.keyAgreementFailed();
-	}
-
-	boolean waitForLocalConfirmationResult() throws InterruptedException {
-		localConfirmationLatch.await(CONFIRMATION_TIMEOUT, MILLISECONDS);
-		lock.lock();
-		try {
-			return localMatched;
-		} finally {
-			lock.unlock();
-		}
-	}
-
-	void remoteConfirmationSucceeded() {
-		lock.lock();
-		try {
-			remoteCompared = true;
-			remoteMatched = true;
-		} finally {
-			lock.unlock();
-		}
-		for (InvitationListener l : listeners) l.remoteConfirmationSucceeded();
-	}
-
-	void remoteConfirmationFailed() {
-		lock.lock();
-		try {
-			remoteCompared = true;
-			remoteMatched = false;
-		} finally {
-			lock.unlock();
-		}
-		for (InvitationListener l : listeners) l.remoteConfirmationFailed();
-	}
-
-	@Override
-	public void contactExchangeSucceeded(Author remoteAuthor) {
-		String name = remoteAuthor.getName();
-		lock.lock();
-		try {
-			remoteName = name;
-		} finally {
-			lock.unlock();
-		}
-		for (InvitationListener l : listeners)
-			l.pseudonymExchangeSucceeded(name);
-	}
-
-	@Override
-	public void duplicateContact(Author remoteAuthor) {
-		// TODO differentiate
-		for (InvitationListener l : listeners) l.pseudonymExchangeFailed();
-	}
-
-	@Override
-	public void contactExchangeFailed() {
-		for (InvitationListener l : listeners) l.pseudonymExchangeFailed();
-	}
-}

bramble-core/src/main/java/org/briarproject/bramble/invitation/InvitationModule.java

@@ -1,16 +0,0 @@
-package org.briarproject.bramble.invitation;
-
-import org.briarproject.bramble.api.invitation.InvitationTaskFactory;
-
-import dagger.Module;
-import dagger.Provides;
-
-@Module
-public class InvitationModule {
-
-	@Provides
-	InvitationTaskFactory provideInvitationTaskFactory(
-			InvitationTaskFactoryImpl invitationTaskFactory) {
-		return invitationTaskFactory;
-	}
-}

bramble-core/src/main/java/org/briarproject/bramble/invitation/InvitationTaskFactoryImpl.java

@@ -1,47 +0,0 @@
-package org.briarproject.bramble.invitation;
-
-import org.briarproject.bramble.api.contact.ContactExchangeTask;
-import org.briarproject.bramble.api.crypto.CryptoComponent;
-import org.briarproject.bramble.api.data.BdfReaderFactory;
-import org.briarproject.bramble.api.data.BdfWriterFactory;
-import org.briarproject.bramble.api.identity.IdentityManager;
-import org.briarproject.bramble.api.invitation.InvitationTask;
-import org.briarproject.bramble.api.invitation.InvitationTaskFactory;
-import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.PluginManager;
-
-import javax.annotation.concurrent.Immutable;
-import javax.inject.Inject;
-
-@Immutable
-@NotNullByDefault
-class InvitationTaskFactoryImpl implements InvitationTaskFactory {
-
-	private final CryptoComponent crypto;
-	private final BdfReaderFactory bdfReaderFactory;
-	private final BdfWriterFactory bdfWriterFactory;
-	private final ContactExchangeTask contactExchangeTask;
-	private final IdentityManager identityManager;
-	private final PluginManager pluginManager;
-
-	@Inject
-	InvitationTaskFactoryImpl(CryptoComponent crypto,
-			BdfReaderFactory bdfReaderFactory,
-			BdfWriterFactory bdfWriterFactory,
-			ContactExchangeTask contactExchangeTask,
-			IdentityManager identityManager, PluginManager pluginManager) {
-		this.crypto = crypto;
-		this.bdfReaderFactory = bdfReaderFactory;
-		this.bdfWriterFactory = bdfWriterFactory;
-		this.contactExchangeTask = contactExchangeTask;
-		this.identityManager = identityManager;
-		this.pluginManager = pluginManager;
-	}
-
-	@Override
-	public InvitationTask createTask(int localCode, int remoteCode) {
-		return new ConnectorGroup(crypto, bdfReaderFactory, bdfWriterFactory,
-				contactExchangeTask, identityManager, pluginManager,
-				localCode, remoteCode);
-	}
-}

bramble-core/src/main/java/org/briarproject/bramble/keyagreement/ConnectionChooser.java

@@ -0,0 +1,36 @@
+package org.briarproject.bramble.keyagreement;
+
+import org.briarproject.bramble.api.keyagreement.KeyAgreementConnection;
+
+import java.util.concurrent.Callable;
+
+import javax.annotation.Nullable;
+
+interface ConnectionChooser {
+
+	/**
+	 * Submits a connection task to the chooser.
+	 */
+	void submit(Callable<KeyAgreementConnection> task);
+
+	/**
+	 * Returns a connection returned by any of the tasks submitted to the
+	 * chooser, waiting up to the given amount of time for a connection if
+	 * necessary. Returns null if the time elapses without a connection
+	 * becoming available.
+	 *
+	 * @param timeout the timeout in milliseconds
+	 * @throws InterruptedException if the thread is interrupted while waiting
+	 * for a connection to become available
+	 */
+	@Nullable
+	KeyAgreementConnection poll(long timeout) throws InterruptedException;
+
+	/**
+	 * Stops the chooser. Any connections already returned to the chooser are
+	 * closed unless they have been removed from the chooser by calling
+	 * {@link #poll(long)}. Any connections subsequently returned to the
+	 * chooser will also be closed.
+	 */
+	void stop();
+}

bramble-core/src/main/java/org/briarproject/bramble/keyagreement/ConnectionChooserImpl.java

@@ -0,0 +1,112 @@
+package org.briarproject.bramble.keyagreement;
+
+import org.briarproject.bramble.api.keyagreement.KeyAgreementConnection;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
+import org.briarproject.bramble.api.system.Clock;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Queue;
+import java.util.concurrent.Callable;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.ThreadSafe;
+import javax.inject.Inject;
+
+import static java.util.logging.Level.INFO;
+
+@NotNullByDefault
+@ThreadSafe
+class ConnectionChooserImpl implements ConnectionChooser {
+
+	private static final Logger LOG =
+			Logger.getLogger(ConnectionChooserImpl.class.getName());
+
+	private final Clock clock;
+	private final Executor ioExecutor;
+	private final Object lock = new Object();
+
+	// The following are locking: lock
+	private boolean stopped = false;
+	private final Queue<KeyAgreementConnection> results = new LinkedList<>();
+
+	@Inject
+	ConnectionChooserImpl(Clock clock, @IoExecutor Executor ioExecutor) {
+		this.clock = clock;
+		this.ioExecutor = ioExecutor;
+	}
+
+	@Override
+	public void submit(Callable<KeyAgreementConnection> task) {
+		ioExecutor.execute(() -> {
+			try {
+				KeyAgreementConnection c = task.call();
+				if (c != null) addResult(c);
+			} catch (Exception e) {
+				if (LOG.isLoggable(INFO)) LOG.info(e.toString());
+			}
+		});
+	}
+
+	@Nullable
+	@Override
+	public KeyAgreementConnection poll(long timeout)
+			throws InterruptedException {
+		long now = clock.currentTimeMillis();
+		long end = now + timeout;
+		synchronized (lock) {
+			while (!stopped && results.isEmpty() && now < end) {
+				lock.wait(end - now);
+				now = clock.currentTimeMillis();
+			}
+			return results.poll();
+		}
+	}
+
+	@Override
+	public void stop() {
+		List<KeyAgreementConnection> unused;
+		synchronized (lock) {
+			unused = new ArrayList<>(results);
+			results.clear();
+			stopped = true;
+			lock.notifyAll();
+		}
+		if (LOG.isLoggable(INFO))
+			LOG.info("Closing " + unused.size() + " unused connections");
+		for (KeyAgreementConnection c : unused) tryToClose(c.getConnection());
+	}
+
+	private void addResult(KeyAgreementConnection c) {
+		if (LOG.isLoggable(INFO))
+			LOG.info("Got connection for " + c.getTransportId());
+		boolean close = false;
+		synchronized (lock) {
+			if (stopped) {
+				close = true;
+			} else {
+				results.add(c);
+				lock.notifyAll();
+			}
+		}
+		if (close) {
+			LOG.info("Already stopped");
+			tryToClose(c.getConnection());
+		}
+	}
+
+	private void tryToClose(DuplexTransportConnection conn) {
+		try {
+			conn.getReader().dispose(false, true);
+			conn.getWriter().dispose(false);
+		} catch (IOException e) {
+			if (LOG.isLoggable(INFO)) LOG.info(e.toString());
+		}
+	}
+}

bramble-core/src/main/java/org/briarproject/bramble/keyagreement/KeyAgreementConnector.java

@@ -13,23 +13,19 @@ import org.briarproject.bramble.api.plugin.PluginManager;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
-import org.briarproject.bramble.api.system.Clock;
 
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.Callable;
-import java.util.concurrent.CompletionService;
-import java.util.concurrent.ExecutionException;
-import java.util.concurrent.Executor;
-import java.util.concurrent.ExecutorCompletionService;
-import java.util.concurrent.Future;
+import java.util.concurrent.CopyOnWriteArrayList;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Logger;
 
 import javax.annotation.Nullable;
 
-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.api.keyagreement.KeyAgreementConstants.CONNECTION_TIMEOUT;
@@ -45,46 +41,42 @@ class KeyAgreementConnector {
 			Logger.getLogger(KeyAgreementConnector.class.getName());
 
 	private final Callbacks callbacks;
-	private final Clock clock;
 	private final CryptoComponent crypto;
 	private final PluginManager pluginManager;
-	private final CompletionService<KeyAgreementConnection> connect;
+	private final ConnectionChooser connectionChooser;
 
 	private final List<KeyAgreementListener> listeners =
-			new ArrayList<KeyAgreementListener>();
-	private final List<Future<KeyAgreementConnection>> pending =
-			new ArrayList<Future<KeyAgreementConnection>>();
+			new CopyOnWriteArrayList<>();
+	private final CountDownLatch aliceLatch = new CountDownLatch(1);
+	private final AtomicBoolean waitingSent = new AtomicBoolean(false);
 
-	private volatile boolean connecting = false;
-	private volatile boolean alice = false;
+	private volatile boolean alice = false, stopped = false;
 
-	KeyAgreementConnector(Callbacks callbacks, Clock clock,
+	KeyAgreementConnector(Callbacks callbacks,
 			CryptoComponent crypto, PluginManager pluginManager,
-			Executor ioExecutor) {
+			ConnectionChooser connectionChooser) {
 		this.callbacks = callbacks;
-		this.clock = clock;
 		this.crypto = crypto;
 		this.pluginManager = pluginManager;
-		connect = new ExecutorCompletionService<KeyAgreementConnection>(
-				ioExecutor);
+		this.connectionChooser = connectionChooser;
 	}
 
-	public Payload listen(KeyPair localKeyPair) {
+	Payload listen(KeyPair localKeyPair) {
 		LOG.info("Starting BQP listeners");
 		// Derive commitment
 		byte[] commitment = crypto.deriveKeyCommitment(
 				localKeyPair.getPublic().getEncoded());
 		// Start all listeners and collect their descriptors
-		List<TransportDescriptor> descriptors =
-				new ArrayList<TransportDescriptor>();
+		List<TransportDescriptor> descriptors = new ArrayList<>();
 		for (DuplexPlugin plugin : pluginManager.getKeyAgreementPlugins()) {
 			KeyAgreementListener l =
 					plugin.createKeyAgreementListener(commitment);
 			if (l != null) {
 				TransportId id = plugin.getId();
 				descriptors.add(new TransportDescriptor(id, l.getDescriptor()));
-				pending.add(connect.submit(new ReadableTask(l.listen())));
+				if (LOG.isLoggable(INFO)) LOG.info("Listening via " + id);
 				listeners.add(l);
+				connectionChooser.submit(new ReadableTask(l::accept));
 			}
 		}
 		return new Payload(commitment, descriptors);
@@ -92,128 +84,92 @@ class KeyAgreementConnector {
 
 	void stopListening() {
 		LOG.info("Stopping BQP listeners");
-		for (KeyAgreementListener l : listeners) {
-			l.close();
-		}
-		listeners.clear();
+		stopped = true;
+		aliceLatch.countDown();
+		for (KeyAgreementListener l : listeners) l.close();
+		connectionChooser.stop();
 	}
 
 	@Nullable
-	public KeyAgreementTransport connect(Payload remotePayload,
-			boolean alice) {
-		// Let the listeners know if we are Alice
-		this.connecting = true;
+	public KeyAgreementTransport connect(Payload remotePayload, boolean alice) {
+		// Let the ReadableTasks know if we are Alice
 		this.alice = alice;
-		long end = clock.currentTimeMillis() + CONNECTION_TIMEOUT;
+		aliceLatch.countDown();
 
 		// Start connecting over supported transports
-		LOG.info("Starting outgoing BQP connections");
+		if (LOG.isLoggable(INFO)) {
+			LOG.info("Starting outgoing BQP connections as "
+					+ (alice ? "Alice" : "Bob"));
+		}
 		for (TransportDescriptor d : remotePayload.getTransportDescriptors()) {
 			Plugin p = pluginManager.getPlugin(d.getId());
 			if (p instanceof DuplexPlugin) {
+				if (LOG.isLoggable(INFO))
+					LOG.info("Connecting via " + d.getId());
 				DuplexPlugin plugin = (DuplexPlugin) p;
-				pending.add(connect.submit(new ReadableTask(
-						new ConnectorTask(plugin, remotePayload.getCommitment(),
-								d.getDescriptor(), end))));
+				byte[] commitment = remotePayload.getCommitment();
+				BdfList descriptor = d.getDescriptor();
+				connectionChooser.submit(new ReadableTask(
+						new ConnectorTask(plugin, commitment, descriptor)));
 			}
 		}
 
 		// Get chosen connection
-		KeyAgreementConnection chosen = null;
 		try {
-			long now = clock.currentTimeMillis();
-			Future<KeyAgreementConnection> f =
-					connect.poll(end - now, MILLISECONDS);
-			if (f == null)
-				return null; // No task completed within the timeout.
-			chosen = f.get();
+			KeyAgreementConnection chosen =
+					connectionChooser.poll(CONNECTION_TIMEOUT);
+			if (chosen == null) return null;
 			return new KeyAgreementTransport(chosen);
 		} catch (InterruptedException e) {
 			LOG.info("Interrupted while waiting for connection");
 			Thread.currentThread().interrupt();
 			return null;
-		} catch (ExecutionException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-			return null;
 		} catch (IOException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			return null;
 		} finally {
 			stopListening();
-			// Close all other connections
-			closePending(chosen);
 		}
 	}
 
-	private void closePending(@Nullable KeyAgreementConnection chosen) {
-		for (Future<KeyAgreementConnection> f : pending) {
-			try {
-				if (f.cancel(true)) {
-					LOG.info("Cancelled task");
-				} else if (!f.isCancelled()) {
-					KeyAgreementConnection c = f.get();
-					if (c != null && c != chosen)
-						tryToClose(c.getConnection(), false);
-				}
-			} catch (InterruptedException e) {
-				LOG.info("Interrupted while closing sockets");
-				Thread.currentThread().interrupt();
-				return;
-			} catch (ExecutionException e) {
-				if (LOG.isLoggable(INFO)) LOG.info(e.toString());
-			}
-		}
-	}
-
-	private void tryToClose(DuplexTransportConnection conn, boolean exception) {
-		try {
-			if (LOG.isLoggable(INFO))
-				LOG.info("Closing connection, exception: " + exception);
-			conn.getReader().dispose(exception, true);
-			conn.getWriter().dispose(exception);
-		} catch (IOException e) {
-			if (LOG.isLoggable(INFO)) LOG.info(e.toString());
-		}
+	private void waitingForAlice() {
+		if (!waitingSent.getAndSet(true)) callbacks.connectionWaiting();
 	}
 
 	private class ConnectorTask implements Callable<KeyAgreementConnection> {
 
 		private final byte[] commitment;
 		private final BdfList descriptor;
-		private final long end;
 		private final DuplexPlugin plugin;
 
 		private ConnectorTask(DuplexPlugin plugin, byte[] commitment,
-				BdfList descriptor, long end) {
+				BdfList descriptor) {
 			this.plugin = plugin;
 			this.commitment = commitment;
 			this.descriptor = descriptor;
-			this.end = end;
 		}
 
+		@Nullable
 		@Override
 		public KeyAgreementConnection call() throws Exception {
-			// Repeat attempts until we connect, get interrupted, or time out
-			while (true) {
-				long now = clock.currentTimeMillis();
-				if (now > end) throw new IOException();
+			// Repeat attempts until we connect, get stopped, or get interrupted
+			while (!stopped) {
 				DuplexTransportConnection conn =
 						plugin.createKeyAgreementConnection(commitment,
-								descriptor, end - now);
+								descriptor);
 				if (conn != null) {
 					if (LOG.isLoggable(INFO))
-						LOG.info(plugin.getId().getString() +
-								": Outgoing connection");
+						LOG.info(plugin.getId() + ": Outgoing connection");
 					return new KeyAgreementConnection(conn, plugin.getId());
 				}
 				// Wait 2s before retry (to circumvent transient failures)
 				Thread.sleep(2000);
 			}
+			return null;
 		}
 	}
 
-	private class ReadableTask
-			implements Callable<KeyAgreementConnection> {
+	private class ReadableTask implements Callable<KeyAgreementConnection> {
 
 		private final Callable<KeyAgreementConnection> connectionTask;
 
@@ -221,24 +177,23 @@ class KeyAgreementConnector {
 			this.connectionTask = connectionTask;
 		}
 
+		@Nullable
 		@Override
 		public KeyAgreementConnection call() throws Exception {
 			KeyAgreementConnection c = connectionTask.call();
+			if (c == null) return null;
+			aliceLatch.await();
+			if (alice || stopped) return c;
+			// Bob waits here for Alice to scan his QR code, determine her
+			// role, and send her key
 			InputStream in = c.getConnection().getReader().getInputStream();
-			boolean waitingSent = false;
-			while (!alice && in.available() == 0) {
-				if (!waitingSent && connecting && !alice) {
-					// Bob waits here until Alice obtains his payload.
-					callbacks.connectionWaiting();
-					waitingSent = true;
-				}
-				if (LOG.isLoggable(INFO)) {
-					LOG.info(c.getTransportId().getString() +
-							": Waiting for connection");
-				}
-				Thread.sleep(1000);
+			while (!stopped && in.available() == 0) {
+				if (LOG.isLoggable(INFO))
+					LOG.info(c.getTransportId() + ": Waiting for data");
+				waitingForAlice();
+				Thread.sleep(500);
 			}
-			if (!alice && LOG.isLoggable(INFO))
+			if (!stopped && LOG.isLoggable(INFO))
 				LOG.info(c.getTransportId().getString() + ": Data available");
 			return c;
 		}

bramble-core/src/main/java/org/briarproject/bramble/keyagreement/KeyAgreementModule.java

@@ -1,19 +1,10 @@
 package org.briarproject.bramble.keyagreement;
 
-import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.data.BdfReaderFactory;
 import org.briarproject.bramble.api.data.BdfWriterFactory;
-import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementTaskFactory;
 import org.briarproject.bramble.api.keyagreement.PayloadEncoder;
 import org.briarproject.bramble.api.keyagreement.PayloadParser;
-import org.briarproject.bramble.api.lifecycle.IoExecutor;
-import org.briarproject.bramble.api.plugin.PluginManager;
-import org.briarproject.bramble.api.system.Clock;
-
-import java.util.concurrent.Executor;
-
-import javax.inject.Singleton;
 
 import dagger.Module;
 import dagger.Provides;
@@ -22,13 +13,9 @@ import dagger.Provides;
 public class KeyAgreementModule {
 
 	@Provides
-	@Singleton
-	KeyAgreementTaskFactory provideKeyAgreementTaskFactory(Clock clock,
-			CryptoComponent crypto, EventBus eventBus,
-			@IoExecutor Executor ioExecutor, PayloadEncoder payloadEncoder,
-			PluginManager pluginManager) {
-		return new KeyAgreementTaskFactoryImpl(clock, crypto, eventBus,
-				ioExecutor, payloadEncoder, pluginManager);
+	KeyAgreementTaskFactory provideKeyAgreementTaskFactory(
+			KeyAgreementTaskFactoryImpl keyAgreementTaskFactory) {
+		return keyAgreementTaskFactory;
 	}
 
 	@Provides
@@ -40,4 +27,10 @@ public class KeyAgreementModule {
 	PayloadParser providePayloadParser(BdfReaderFactory bdfReaderFactory) {
 		return new PayloadParserImpl(bdfReaderFactory);
 	}
+
+	@Provides
+	ConnectionChooser provideConnectionChooser(
+			ConnectionChooserImpl connectionChooser) {
+		return connectionChooser;
+	}
 }

bramble-core/src/main/java/org/briarproject/bramble/keyagreement/KeyAgreementProtocol.java

@@ -89,7 +89,8 @@ class KeyAgreementProtocol {
 			byte[] theirPublicKey;
 			if (alice) {
 				sendKey();
-				// Alice waits here until Bob obtains her payload.
+				// Alice waits here for Bob to scan her QR code, determine his
+				// role, receive her key and respond with his key
 				callbacks.connectionWaiting();
 				theirPublicKey = receiveKey();
 			} else {

bramble-core/src/main/java/org/briarproject/bramble/keyagreement/KeyAgreementTaskFactoryImpl.java

@@ -5,42 +5,37 @@ import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementTask;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementTaskFactory;
 import org.briarproject.bramble.api.keyagreement.PayloadEncoder;
-import org.briarproject.bramble.api.lifecycle.IoExecutor;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.PluginManager;
-import org.briarproject.bramble.api.system.Clock;
-
-import java.util.concurrent.Executor;
 
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
+import javax.inject.Provider;
 
 @Immutable
 @NotNullByDefault
 class KeyAgreementTaskFactoryImpl implements KeyAgreementTaskFactory {
 
-	private final Clock clock;
 	private final CryptoComponent crypto;
 	private final EventBus eventBus;
-	private final Executor ioExecutor;
 	private final PayloadEncoder payloadEncoder;
 	private final PluginManager pluginManager;
+	private final Provider<ConnectionChooser> connectionChooserProvider;
 
 	@Inject
-	KeyAgreementTaskFactoryImpl(Clock clock, CryptoComponent crypto,
-			EventBus eventBus, @IoExecutor Executor ioExecutor,
-			PayloadEncoder payloadEncoder, PluginManager pluginManager) {
-		this.clock = clock;
+	KeyAgreementTaskFactoryImpl(CryptoComponent crypto, EventBus eventBus,
+			PayloadEncoder payloadEncoder, PluginManager pluginManager,
+			Provider<ConnectionChooser> connectionChooserProvider) {
 		this.crypto = crypto;
 		this.eventBus = eventBus;
-		this.ioExecutor = ioExecutor;
 		this.payloadEncoder = payloadEncoder;
 		this.pluginManager = pluginManager;
+		this.connectionChooserProvider = connectionChooserProvider;
 	}
 
 	@Override
 	public KeyAgreementTask createTask() {
-		return new KeyAgreementTaskImpl(clock, crypto, eventBus, payloadEncoder,
-				pluginManager, ioExecutor);
+		return new KeyAgreementTaskImpl(crypto, eventBus, payloadEncoder,
+				pluginManager, connectionChooserProvider.get());
 	}
 }

bramble-core/src/main/java/org/briarproject/bramble/keyagreement/KeyAgreementTaskImpl.java

@@ -17,19 +17,16 @@ import org.briarproject.bramble.api.keyagreement.event.KeyAgreementWaitingEvent;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
 import org.briarproject.bramble.api.plugin.PluginManager;
-import org.briarproject.bramble.api.system.Clock;
 
 import java.io.IOException;
-import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
 import static java.util.logging.Level.WARNING;
 
 @MethodsNotNullByDefault
 @ParametersNotNullByDefault
-class KeyAgreementTaskImpl extends Thread implements
-		KeyAgreementTask, KeyAgreementConnector.Callbacks,
-		KeyAgreementProtocol.Callbacks {
+class KeyAgreementTaskImpl extends Thread implements KeyAgreementTask,
+		KeyAgreementProtocol.Callbacks, KeyAgreementConnector.Callbacks {
 
 	private static final Logger LOG =
 			Logger.getLogger(KeyAgreementTaskImpl.class.getName());
@@ -43,15 +40,15 @@ class KeyAgreementTaskImpl extends Thread implements
 	private Payload localPayload;
 	private Payload remotePayload;
 
-	KeyAgreementTaskImpl(Clock clock, CryptoComponent crypto,
-			EventBus eventBus, PayloadEncoder payloadEncoder,
-			PluginManager pluginManager, Executor ioExecutor) {
+	KeyAgreementTaskImpl(CryptoComponent crypto, EventBus eventBus,
+			PayloadEncoder payloadEncoder, PluginManager pluginManager,
+			ConnectionChooser connectionChooser) {
 		this.crypto = crypto;
 		this.eventBus = eventBus;
 		this.payloadEncoder = payloadEncoder;
 		localKeyPair = crypto.generateAgreementKeyPair();
-		connector = new KeyAgreementConnector(this, clock, crypto,
-				pluginManager, ioExecutor);
+		connector = new KeyAgreementConnector(this, crypto, pluginManager,
+				connectionChooser);
 	}
 
 	@Override
@@ -65,10 +62,8 @@ class KeyAgreementTaskImpl extends Thread implements
 	@Override
 	public synchronized void stopListening() {
 		if (localPayload != null) {
-			if (remotePayload == null)
-				connector.stopListening();
-			else
-				interrupt();
+			if (remotePayload == null) connector.stopListening();
+			else interrupt();
 		}
 	}
 

bramble-core/src/main/java/org/briarproject/bramble/keyagreement/PayloadParserImpl.java

@@ -51,8 +51,7 @@ class PayloadParserImpl implements PayloadParser {
 		byte[] commitment = payload.getRaw(1);
 		if (commitment.length != COMMIT_LENGTH) throw new FormatException();
 		// Remaining elements: transport descriptors
-		List<TransportDescriptor> recognised =
-				new ArrayList<TransportDescriptor>();
+		List<TransportDescriptor> recognised = new ArrayList<>();
 		for (int i = 2; i < payload.size(); i++) {
 			BdfList descriptor = payload.getList(i);
 			long transportId = descriptor.getLong(0);

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

@@ -2,8 +2,11 @@ package org.briarproject.bramble.lifecycle;
 
 import org.briarproject.bramble.api.crypto.CryptoComponent;
 import org.briarproject.bramble.api.crypto.KeyPair;
+import org.briarproject.bramble.api.db.DataTooNewException;
+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.AuthorFactory;
@@ -12,7 +15,7 @@ import org.briarproject.bramble.api.identity.LocalAuthor;
 import org.briarproject.bramble.api.lifecycle.LifecycleManager;
 import org.briarproject.bramble.api.lifecycle.Service;
 import org.briarproject.bramble.api.lifecycle.ServiceException;
-import org.briarproject.bramble.api.lifecycle.event.ShutdownEvent;
+import org.briarproject.bramble.api.lifecycle.event.LifecycleEvent;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.Client;
 
@@ -29,14 +32,21 @@ import javax.inject.Inject;
 
 import static java.util.logging.Level.INFO;
 import static java.util.logging.Level.WARNING;
+import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.MIGRATING_DATABASE;
+import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.RUNNING;
+import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.STARTING;
+import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.STARTING_SERVICES;
+import static org.briarproject.bramble.api.lifecycle.LifecycleManager.LifecycleState.STOPPING;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.StartResult.ALREADY_RUNNING;
+import static org.briarproject.bramble.api.lifecycle.LifecycleManager.StartResult.DATA_TOO_NEW_ERROR;
+import static org.briarproject.bramble.api.lifecycle.LifecycleManager.StartResult.DATA_TOO_OLD_ERROR;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.StartResult.DB_ERROR;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.StartResult.SERVICE_ERROR;
 import static org.briarproject.bramble.api.lifecycle.LifecycleManager.StartResult.SUCCESS;
 
 @ThreadSafe
 @NotNullByDefault
-class LifecycleManagerImpl implements LifecycleManager {
+class LifecycleManagerImpl implements LifecycleManager, MigrationListener {
 
 	private static final Logger LOG =
 			Logger.getLogger(LifecycleManagerImpl.class.getName());
@@ -54,6 +64,8 @@ class LifecycleManagerImpl implements LifecycleManager {
 	private final CountDownLatch startupLatch = new CountDownLatch(1);
 	private final CountDownLatch shutdownLatch = new CountDownLatch(1);
 
+	private volatile LifecycleState state = STARTING;
+
 	@Inject
 	LifecycleManagerImpl(DatabaseComponent db, EventBus eventBus,
 			CryptoComponent crypto, AuthorFactory authorFactory,
@@ -63,9 +75,9 @@ class LifecycleManagerImpl implements LifecycleManager {
 		this.crypto = crypto;
 		this.authorFactory = authorFactory;
 		this.identityManager = identityManager;
-		services = new CopyOnWriteArrayList<Service>();
-		clients = new CopyOnWriteArrayList<Client>();
-		executors = new CopyOnWriteArrayList<ExecutorService>();
+		services = new CopyOnWriteArrayList<>();
+		clients = new CopyOnWriteArrayList<>();
+		executors = new CopyOnWriteArrayList<>();
 	}
 
 	@Override
@@ -88,7 +100,7 @@ class LifecycleManagerImpl implements LifecycleManager {
 		executors.add(e);
 	}
 
-	private LocalAuthor createLocalAuthor(final String nickname) {
+	private LocalAuthor createLocalAuthor(String nickname) {
 		long now = System.currentTimeMillis();
 		KeyPair keyPair = crypto.generateSignatureKeyPair();
 		byte[] publicKey = keyPair.getPublic().getEncoded();
@@ -119,7 +131,7 @@ class LifecycleManagerImpl implements LifecycleManager {
 			LOG.info("Starting services");
 			long start = System.currentTimeMillis();
 
-			boolean reopened = db.open();
+			boolean reopened = db.open(this);
 			long duration = System.currentTimeMillis() - start;
 			if (LOG.isLoggable(INFO)) {
 				if (reopened)
@@ -131,7 +143,10 @@ class LifecycleManagerImpl implements LifecycleManager {
 				registerLocalAuthor(createLocalAuthor(nickname));
 			}
 
+			state = STARTING_SERVICES;
 			dbLatch.countDown();
+			eventBus.broadcast(new LifecycleEvent(STARTING_SERVICES));
+
 			Transaction txn = db.startTransaction(false);
 			try {
 				for (Client c : clients) {
@@ -157,8 +172,17 @@ class LifecycleManagerImpl implements LifecycleManager {
 							+ " took " + duration + " ms");
 				}
 			}
+
+			state = RUNNING;
 			startupLatch.countDown();
+			eventBus.broadcast(new LifecycleEvent(RUNNING));
 			return SUCCESS;
+		} catch (DataTooOldException e) {
+			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+			return DATA_TOO_OLD_ERROR;
+		} catch (DataTooNewException e) {
+			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+			return DATA_TOO_NEW_ERROR;
 		} catch (DbException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			return DB_ERROR;
@@ -170,6 +194,12 @@ class LifecycleManagerImpl implements LifecycleManager {
 		}
 	}
 
+	@Override
+	public void onMigrationRun() {
+		state = MIGRATING_DATABASE;
+		eventBus.broadcast(new LifecycleEvent(MIGRATING_DATABASE));
+	}
+
 	@Override
 	public void stopServices() {
 		try {
@@ -180,7 +210,8 @@ class LifecycleManagerImpl implements LifecycleManager {
 		}
 		try {
 			LOG.info("Stopping services");
-			eventBus.broadcast(new ShutdownEvent());
+			state = STOPPING;
+			eventBus.broadcast(new LifecycleEvent(STOPPING));
 			for (Service s : services) {
 				long start = System.currentTimeMillis();
 				s.stopService();
@@ -203,9 +234,7 @@ class LifecycleManagerImpl implements LifecycleManager {
 			if (LOG.isLoggable(INFO))
 				LOG.info("Closing database took " + duration + " ms");
 			shutdownLatch.countDown();
-		} catch (DbException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		} catch (ServiceException e) {
+		} catch (DbException | ServiceException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 		} finally {
 			startStopSemaphore.release();
@@ -227,4 +256,8 @@ class LifecycleManagerImpl implements LifecycleManager {
 		shutdownLatch.await();
 	}
 
+	@Override
+	public LifecycleState getLifecycleState() {
+		return state;
+	}
 }

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

@@ -37,7 +37,7 @@ public class LifecycleModule {
 
 	public LifecycleModule() {
 		// The thread pool is unbounded, so use direct handoff
-		BlockingQueue<Runnable> queue = new SynchronousQueue<Runnable>();
+		BlockingQueue<Runnable> queue = new SynchronousQueue<>();
 		// Discard tasks that are submitted during shutdown
 		RejectedExecutionHandler policy =
 				new ThreadPoolExecutor.DiscardPolicy();

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

@@ -21,7 +21,7 @@ class ShutdownManagerImpl implements ShutdownManager {
 	private int nextHandle = 0;
 
 	ShutdownManagerImpl() {
-		hooks = new HashMap<Integer, Thread>();
+		hooks = new HashMap<>();
 	}
 
 	@Override

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

@@ -134,11 +134,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 			try {
 				byte[] tag = readTag(reader);
 				ctx = keyManager.getStreamContext(transportId, tag);
-			} catch (IOException e) {
-				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-				disposeReader(true, false);
-				return;
-			} catch (DbException e) {
+			} catch (IOException | DbException e) {
 				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 				disposeReader(true, false);
 				return;
@@ -249,11 +245,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 			try {
 				byte[] tag = readTag(reader);
 				ctx = keyManager.getStreamContext(transportId, tag);
-			} catch (IOException e) {
-				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-				disposeReader(true, false);
-				return;
-			} catch (DbException e) {
+			} catch (IOException | DbException e) {
 				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 				disposeReader(true, false);
 				return;
@@ -266,12 +258,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 			contactId = ctx.getContactId();
 			connectionRegistry.registerConnection(contactId, transportId, true);
 			// Start the outgoing session on another thread
-			ioExecutor.execute(new Runnable() {
-				@Override
-				public void run() {
-					runOutgoingSession();
-				}
-			});
+			ioExecutor.execute(this::runOutgoingSession);
 			try {
 				// Create and run the incoming session
 				incomingSession = createIncomingSession(ctx, reader);
@@ -368,12 +355,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 				return;
 			}
 			// Start the incoming session on another thread
-			ioExecutor.execute(new Runnable() {
-				@Override
-				public void run() {
-					runIncomingSession();
-				}
-			});
+			ioExecutor.execute(this::runIncomingSession);
 			try {
 				// Create and run the outgoing session
 				outgoingSession = createDuplexOutgoingSession(ctx, writer);
@@ -391,11 +373,7 @@ class ConnectionManagerImpl implements ConnectionManager {
 			try {
 				byte[] tag = readTag(reader);
 				ctx = keyManager.getStreamContext(transportId, tag);
-			} catch (IOException e) {
-				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-				disposeReader(true, false);
-				return;
-			} catch (DbException e) {
+			} catch (IOException | DbException e) {
 				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 				disposeReader(true, false);
 				return;

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

@@ -42,8 +42,8 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 	@Inject
 	ConnectionRegistryImpl(EventBus eventBus) {
 		this.eventBus = eventBus;
-		connections = new HashMap<TransportId, Map<ContactId, Integer>>();
-		contactCounts = new HashMap<ContactId, Integer>();
+		connections = new HashMap<>();
+		contactCounts = new HashMap<>();
 	}
 
 	@Override
@@ -58,7 +58,7 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 		try {
 			Map<ContactId, Integer> m = connections.get(t);
 			if (m == null) {
-				m = new HashMap<ContactId, Integer>();
+				m = new HashMap<>();
 				connections.put(t, m);
 			}
 			Integer count = m.get(c);
@@ -124,7 +124,7 @@ class ConnectionRegistryImpl implements ConnectionRegistry {
 		try {
 			Map<ContactId, Integer> m = connections.get(t);
 			if (m == null) return Collections.emptyList();
-			List<ContactId> ids = new ArrayList<ContactId>(m.keySet());
+			List<ContactId> ids = new ArrayList<>(m.keySet());
 			if (LOG.isLoggable(INFO))
 				LOG.info(ids.size() + " contacts connected");
 			return ids;

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

@@ -82,10 +82,10 @@ class PluginManagerImpl implements PluginManager, Service {
 		this.settingsManager = settingsManager;
 		this.transportPropertyManager = transportPropertyManager;
 		this.uiCallback = uiCallback;
-		plugins = new ConcurrentHashMap<TransportId, Plugin>();
-		simplexPlugins = new CopyOnWriteArrayList<SimplexPlugin>();
-		duplexPlugins = new CopyOnWriteArrayList<DuplexPlugin>();
-		startLatches = new ConcurrentHashMap<TransportId, CountDownLatch>();
+		plugins = new ConcurrentHashMap<>();
+		simplexPlugins = new CopyOnWriteArrayList<>();
+		duplexPlugins = new CopyOnWriteArrayList<>();
+		startLatches = new ConcurrentHashMap<>();
 	}
 
 	@Override
@@ -156,25 +156,17 @@ class PluginManagerImpl implements PluginManager, Service {
 
 	@Override
 	public Collection<SimplexPlugin> getSimplexPlugins() {
-		return new ArrayList<SimplexPlugin>(simplexPlugins);
+		return new ArrayList<>(simplexPlugins);
 	}
 
 	@Override
 	public Collection<DuplexPlugin> getDuplexPlugins() {
-		return new ArrayList<DuplexPlugin>(duplexPlugins);
-	}
-
-	@Override
-	public Collection<DuplexPlugin> getInvitationPlugins() {
-		List<DuplexPlugin> supported = new ArrayList<DuplexPlugin>();
-		for (DuplexPlugin d : duplexPlugins)
-			if (d.supportsInvitations()) supported.add(d);
-		return supported;
+		return new ArrayList<>(duplexPlugins);
 	}
 
 	@Override
 	public Collection<DuplexPlugin> getKeyAgreementPlugins() {
-		List<DuplexPlugin> supported = new ArrayList<DuplexPlugin>();
+		List<DuplexPlugin> supported = new ArrayList<>();
 		for (DuplexPlugin d : duplexPlugins)
 			if (d.supportsKeyAgreement()) supported.add(d);
 		return supported;
@@ -291,6 +283,16 @@ class PluginManagerImpl implements PluginManager, Service {
 			}
 		}
 
+		@Override
+		public TransportProperties getRemoteProperties(ContactId c) {
+			try {
+				return transportPropertyManager.getRemoteProperties(c, id);
+			} catch (DbException e) {
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+				return new TransportProperties();
+			}
+		}
+
 		@Override
 		public void mergeSettings(Settings s) {
 			try {

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

@@ -16,6 +16,7 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPlugin;
 import org.briarproject.bramble.api.plugin.duplex.DuplexTransportConnection;
 import org.briarproject.bramble.api.plugin.event.ConnectionClosedEvent;
 import org.briarproject.bramble.api.plugin.event.ConnectionOpenedEvent;
+import org.briarproject.bramble.api.plugin.event.TransportDisabledEvent;
 import org.briarproject.bramble.api.plugin.event.TransportEnabledEvent;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
 import org.briarproject.bramble.api.system.Clock;
@@ -25,6 +26,7 @@ import java.security.SecureRandom;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.Executor;
+import java.util.concurrent.Future;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
@@ -50,7 +52,7 @@ class Poller implements EventListener {
 	private final SecureRandom random;
 	private final Clock clock;
 	private final Lock lock;
-	private final Map<TransportId, PollTask> tasks; // Locking: lock
+	private final Map<TransportId, ScheduledPollTask> tasks; // Locking: lock
 
 	@Inject
 	Poller(@IoExecutor Executor ioExecutor,
@@ -66,7 +68,7 @@ class Poller implements EventListener {
 		this.random = random;
 		this.clock = clock;
 		lock = new ReentrantLock();
-		tasks = new HashMap<TransportId, PollTask>();
+		tasks = new HashMap<>();
 	}
 
 	@Override
@@ -93,6 +95,10 @@ class Poller implements EventListener {
 			TransportEnabledEvent t = (TransportEnabledEvent) e;
 			// Poll the newly enabled transport
 			pollNow(t.getTransportId());
+		} else if (e instanceof TransportDisabledEvent) {
+			TransportDisabledEvent t = (TransportDisabledEvent) e;
+			// Cancel polling for the disabled transport
+			cancel(t.getTransportId());
 		}
 	}
 
@@ -111,30 +117,24 @@ class Poller implements EventListener {
 			connectToContact(c, (DuplexPlugin) p);
 	}
 
-	private void connectToContact(final ContactId c, final SimplexPlugin p) {
-		ioExecutor.execute(new Runnable() {
-			@Override
-			public void run() {
-				TransportId t = p.getId();
-				if (!connectionRegistry.isConnected(c, t)) {
-					TransportConnectionWriter w = p.createWriter(c);
-					if (w != null)
-						connectionManager.manageOutgoingConnection(c, t, w);
-				}
+	private void connectToContact(ContactId c, SimplexPlugin p) {
+		ioExecutor.execute(() -> {
+			TransportId t = p.getId();
+			if (!connectionRegistry.isConnected(c, t)) {
+				TransportConnectionWriter w = p.createWriter(c);
+				if (w != null)
+					connectionManager.manageOutgoingConnection(c, t, w);
 			}
 		});
 	}
 
-	private void connectToContact(final ContactId c, final DuplexPlugin p) {
-		ioExecutor.execute(new Runnable() {
-			@Override
-			public void run() {
-				TransportId t = p.getId();
-				if (!connectionRegistry.isConnected(c, t)) {
-					DuplexTransportConnection d = p.createConnection(c);
-					if (d != null)
-						connectionManager.manageOutgoingConnection(c, t, d);
-				}
+	private void connectToContact(ContactId c, DuplexPlugin p) {
+		ioExecutor.execute(() -> {
+			TransportId t = p.getId();
+			if (!connectionRegistry.isConnected(c, t)) {
+				DuplexTransportConnection d = p.createConnection(c);
+				if (d != null)
+					connectionManager.manageOutgoingConnection(c, t, d);
 			}
 		});
 	}
@@ -157,29 +157,49 @@ class Poller implements EventListener {
 		TransportId t = p.getId();
 		lock.lock();
 		try {
-			PollTask scheduled = tasks.get(t);
-			if (scheduled == null || due < scheduled.due) {
-				final PollTask task = new PollTask(p, due, randomiseNext);
-				tasks.put(t, task);
-				scheduler.schedule(new Runnable() {
-					@Override
-					public void run() {
-						ioExecutor.execute(task);
-					}
-				}, delay, MILLISECONDS);
+			ScheduledPollTask scheduled = tasks.get(t);
+			if (scheduled == null || due < scheduled.task.due) {
+				// If a later task exists, cancel it. If it's already started
+				// it will abort safely when it finds it's been replaced
+				if (scheduled != null) scheduled.future.cancel(false);
+				PollTask task = new PollTask(p, due, randomiseNext);
+				Future future = scheduler.schedule(
+						() -> ioExecutor.execute(task), delay, MILLISECONDS);
+				tasks.put(t, new ScheduledPollTask(task, future));
 			}
 		} finally {
 			lock.unlock();
 		}
 	}
 
+	private void cancel(TransportId t) {
+		lock.lock();
+		try {
+			ScheduledPollTask scheduled = tasks.remove(t);
+			if (scheduled != null) scheduled.future.cancel(false);
+		} finally {
+			lock.unlock();
+		}
+	}
+
 	@IoExecutor
-	private void poll(final Plugin p) {
+	private void poll(Plugin p) {
 		TransportId t = p.getId();
 		if (LOG.isLoggable(INFO)) LOG.info("Polling plugin " + t);
 		p.poll(connectionRegistry.getConnectedContacts(t));
 	}
 
+	private class ScheduledPollTask {
+
+		private final PollTask task;
+		private final Future future;
+
+		private ScheduledPollTask(PollTask task, Future future) {
+			this.task = task;
+			this.future = future;
+		}
+	}
+
 	private class PollTask implements Runnable {
 
 		private final Plugin plugin;
@@ -198,7 +218,9 @@ class Poller implements EventListener {
 			lock.lock();
 			try {
 				TransportId t = plugin.getId();
-				if (tasks.get(t) != this) return; // Replaced by another task
+				ScheduledPollTask scheduled = tasks.get(t);
+				if (scheduled != null && scheduled.task != this)
+					return; // Replaced by another task
 				tasks.remove(t);
 			} finally {
 				lock.unlock();

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

@@ -0,0 +1,419 @@
+package org.briarproject.bramble.plugin.bluetooth;
+
+import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.data.BdfList;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventListener;
+import org.briarproject.bramble.api.keyagreement.KeyAgreementConnection;
+import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.bramble.api.plugin.Backoff;
+import org.briarproject.bramble.api.plugin.PluginException;
+import org.briarproject.bramble.api.plugin.TransportId;
+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.plugin.event.BluetoothEnabledEvent;
+import org.briarproject.bramble.api.plugin.event.DisableBluetoothEvent;
+import org.briarproject.bramble.api.plugin.event.EnableBluetoothEvent;
+import org.briarproject.bramble.api.properties.TransportProperties;
+import org.briarproject.bramble.api.settings.event.SettingsUpdatedEvent;
+import org.briarproject.bramble.util.StringUtils;
+
+import java.io.IOException;
+import java.security.SecureRandom;
+import java.util.Collection;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.UUID;
+import java.util.concurrent.Executor;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Level.WARNING;
+import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.TRANSPORT_ID_BLUETOOTH;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.ID;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.PREF_BT_ENABLE;
+import static org.briarproject.bramble.api.plugin.BluetoothConstants.PROP_ADDRESS;
+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.PrivacyUtils.scrubMacAddress;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+abstract class BluetoothPlugin<SS> implements DuplexPlugin, EventListener {
+
+	private static final Logger LOG =
+			Logger.getLogger(BluetoothPlugin.class.getName());
+
+	private final Executor ioExecutor;
+	private final SecureRandom secureRandom;
+	private final Backoff backoff;
+	private final DuplexPluginCallback callback;
+	private final int maxLatency;
+	private final AtomicBoolean used = new AtomicBoolean(false);
+
+	private volatile boolean running = false, contactConnections = false;
+	private volatile String contactConnectionsUuid = null;
+	private volatile SS socket = null;
+
+	abstract void initialiseAdapter() throws IOException;
+
+	abstract boolean isAdapterEnabled();
+
+	abstract void enableAdapter();
+
+	abstract void disableAdapterIfEnabledByUs();
+
+	abstract void setEnabledByUs();
+
+	/**
+	 * Returns the local Bluetooth address, or null if no valid address can
+	 * be found.
+	 */
+	@Nullable
+	abstract String getBluetoothAddress();
+
+	abstract SS openServerSocket(String uuid) throws IOException;
+
+	abstract void tryToClose(@Nullable SS ss);
+
+	abstract DuplexTransportConnection acceptConnection(SS ss)
+			throws IOException;
+
+	abstract boolean isValidAddress(String address);
+
+	abstract DuplexTransportConnection connectTo(String address, String uuid)
+			throws IOException;
+
+	BluetoothPlugin(Executor ioExecutor, SecureRandom secureRandom,
+			Backoff backoff, DuplexPluginCallback callback, int maxLatency) {
+		this.ioExecutor = ioExecutor;
+		this.secureRandom = secureRandom;
+		this.backoff = backoff;
+		this.callback = callback;
+		this.maxLatency = maxLatency;
+	}
+
+	void onAdapterEnabled() {
+		LOG.info("Bluetooth enabled");
+		// We may not have been able to get the local address before
+		ioExecutor.execute(this::updateProperties);
+		if (shouldAllowContactConnections()) bind();
+	}
+
+	void onAdapterDisabled() {
+		LOG.info("Bluetooth disabled");
+		tryToClose(socket);
+		callback.transportDisabled();
+	}
+
+	@Override
+	public TransportId getId() {
+		return ID;
+	}
+
+	@Override
+	public int getMaxLatency() {
+		return maxLatency;
+	}
+
+	@Override
+	public int getMaxIdleTime() {
+		// Bluetooth detects dead connections so we don't need keepalives
+		return Integer.MAX_VALUE;
+	}
+
+	@Override
+	public void start() throws PluginException {
+		if (used.getAndSet(true)) throw new IllegalStateException();
+		try {
+			initialiseAdapter();
+		} catch (IOException e) {
+			throw new PluginException(e);
+		}
+		updateProperties();
+		running = true;
+		loadSettings();
+		if (shouldAllowContactConnections()) {
+			if (isAdapterEnabled()) bind();
+			else enableAdapter();
+		}
+	}
+
+	private void loadSettings() {
+		contactConnections =
+				callback.getSettings().getBoolean(PREF_BT_ENABLE, false);
+	}
+
+	private boolean shouldAllowContactConnections() {
+		return contactConnections;
+	}
+
+	private void bind() {
+		ioExecutor.execute(() -> {
+			if (!isRunning() || !shouldAllowContactConnections()) return;
+			// Bind a server socket to accept connections from contacts
+			SS ss;
+			try {
+				ss = openServerSocket(contactConnectionsUuid);
+			} catch (IOException e) {
+				if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+				return;
+			}
+			if (!isRunning() || !shouldAllowContactConnections()) {
+				tryToClose(ss);
+				return;
+			}
+			socket = ss;
+			backoff.reset();
+			callback.transportEnabled();
+			acceptContactConnections();
+		});
+	}
+
+	private void updateProperties() {
+		TransportProperties p = callback.getLocalProperties();
+		String address = p.get(PROP_ADDRESS);
+		String uuid = p.get(PROP_UUID);
+		boolean changed = false;
+		if (address == null) {
+			address = getBluetoothAddress();
+			if (LOG.isLoggable(INFO))
+				LOG.info("Local address " + scrubMacAddress(address));
+			if (!StringUtils.isNullOrEmpty(address)) {
+				p.put(PROP_ADDRESS, address);
+				changed = true;
+			}
+		}
+		if (uuid == null) {
+			byte[] random = new byte[UUID_BYTES];
+			secureRandom.nextBytes(random);
+			uuid = UUID.nameUUIDFromBytes(random).toString();
+			p.put(PROP_UUID, uuid);
+			changed = true;
+		}
+		contactConnectionsUuid = uuid;
+		if (changed) callback.mergeLocalProperties(p);
+	}
+
+	private void acceptContactConnections() {
+		while (true) {
+			DuplexTransportConnection conn;
+			try {
+				conn = acceptConnection(socket);
+			} catch (IOException e) {
+				// This is expected when the socket is closed
+				if (LOG.isLoggable(INFO)) LOG.info(e.toString());
+				return;
+			}
+			backoff.reset();
+			callback.incomingConnectionCreated(conn);
+			if (!running) return;
+		}
+	}
+
+	@Override
+	public void stop() {
+		running = false;
+		tryToClose(socket);
+		callback.transportDisabled();
+		disableAdapterIfEnabledByUs();
+	}
+
+	@Override
+	public boolean isRunning() {
+		return running && isAdapterEnabled();
+	}
+
+	@Override
+	public boolean shouldPoll() {
+		return true;
+	}
+
+	@Override
+	public int getPollingInterval() {
+		return backoff.getPollingInterval();
+	}
+
+	@Override
+	public void poll(Collection<ContactId> connected) {
+		if (!isRunning() || !shouldAllowContactConnections()) return;
+		backoff.increment();
+		// Try to connect to known devices in parallel
+		Map<ContactId, TransportProperties> remote =
+				callback.getRemoteProperties();
+		for (Entry<ContactId, TransportProperties> e : remote.entrySet()) {
+			ContactId c = e.getKey();
+			if (connected.contains(c)) continue;
+			String address = e.getValue().get(PROP_ADDRESS);
+			if (StringUtils.isNullOrEmpty(address)) continue;
+			String uuid = e.getValue().get(PROP_UUID);
+			if (StringUtils.isNullOrEmpty(uuid)) continue;
+			ioExecutor.execute(() -> {
+				if (!isRunning() || !shouldAllowContactConnections()) return;
+				DuplexTransportConnection conn = connect(address, uuid);
+				if (conn != null) {
+					backoff.reset();
+					callback.outgoingConnectionCreated(c, conn);
+				}
+			});
+		}
+	}
+
+	@Nullable
+	private DuplexTransportConnection connect(String address, String uuid) {
+		// Validate the address
+		if (!isValidAddress(address)) {
+			if (LOG.isLoggable(WARNING))
+				// Not scrubbing here to be able to figure out the problem
+				LOG.warning("Invalid address " + address);
+			return null;
+		}
+		// Validate the UUID
+		try {
+			//noinspection ResultOfMethodCallIgnored
+			UUID.fromString(uuid);
+		} catch (IllegalArgumentException e) {
+			if (LOG.isLoggable(WARNING)) LOG.warning("Invalid UUID " + uuid);
+			return null;
+		}
+		if (LOG.isLoggable(INFO))
+			LOG.info("Connecting to " + scrubMacAddress(address));
+		try {
+			DuplexTransportConnection conn = connectTo(address, uuid);
+			if (LOG.isLoggable(INFO))
+				LOG.info("Connected to " + scrubMacAddress(address));
+			return conn;
+		} catch (IOException e) {
+			if (LOG.isLoggable(INFO))
+				LOG.info("Could not connect to " + scrubMacAddress(address));
+			return null;
+		}
+	}
+
+	@Override
+	public DuplexTransportConnection createConnection(ContactId c) {
+		if (!isRunning() || !shouldAllowContactConnections()) return null;
+		TransportProperties p = callback.getRemoteProperties(c);
+		String address = p.get(PROP_ADDRESS);
+		if (StringUtils.isNullOrEmpty(address)) return null;
+		String uuid = p.get(PROP_UUID);
+		if (StringUtils.isNullOrEmpty(uuid)) return null;
+		return connect(address, uuid);
+	}
+
+	@Override
+	public boolean supportsKeyAgreement() {
+		return true;
+	}
+
+	@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);
+		// Bind a server socket for receiving key agreement connections
+		SS ss;
+		try {
+			ss = openServerSocket(uuid);
+		} catch (IOException e) {
+			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
+			return null;
+		}
+		if (!isRunning()) {
+			tryToClose(ss);
+			return null;
+		}
+		BdfList descriptor = new BdfList();
+		descriptor.add(TRANSPORT_ID_BLUETOOTH);
+		descriptor.add(StringUtils.macToBytes(address));
+		return new BluetoothKeyAgreementListener(descriptor, ss);
+	}
+
+	@Override
+	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();
+		if (LOG.isLoggable(INFO))
+			LOG.info("Connecting to key agreement UUID " + uuid);
+		return connect(address, uuid);
+	}
+
+	private String parseAddress(BdfList descriptor) throws FormatException {
+		byte[] mac = descriptor.getRaw(1);
+		if (mac.length != 6) throw new FormatException();
+		return StringUtils.macToString(mac);
+	}
+
+	@Override
+	public void eventOccurred(Event e) {
+		if (e instanceof EnableBluetoothEvent) {
+			ioExecutor.execute(this::enableAdapter);
+		} else if (e instanceof DisableBluetoothEvent) {
+			ioExecutor.execute(this::disableAdapterIfEnabledByUs);
+		} else if (e instanceof BluetoothEnabledEvent) {
+			setEnabledByUs();
+		} else if (e instanceof SettingsUpdatedEvent) {
+			SettingsUpdatedEvent s = (SettingsUpdatedEvent) e;
+			if (s.getNamespace().equals(ID.getString()))
+				ioExecutor.execute(this::onSettingsUpdated);
+		}
+	}
+
+	private void onSettingsUpdated() {
+		boolean wasAllowed = shouldAllowContactConnections();
+		loadSettings();
+		boolean isAllowed = shouldAllowContactConnections();
+		if (wasAllowed && !isAllowed) {
+			LOG.info("Contact connections disabled");
+			tryToClose(socket);
+			callback.transportDisabled();
+			disableAdapterIfEnabledByUs();
+		} else if (!wasAllowed && isAllowed) {
+			LOG.info("Contact connections enabled");
+			if (isAdapterEnabled()) bind();
+			else enableAdapter();
+		}
+	}
+
+	private class BluetoothKeyAgreementListener extends KeyAgreementListener {
+
+		private final SS ss;
+
+		private BluetoothKeyAgreementListener(BdfList descriptor, SS ss) {
+			super(descriptor);
+			this.ss = ss;
+		}
+
+		@Override
+		public KeyAgreementConnection accept() throws IOException {
+			DuplexTransportConnection conn = acceptConnection(ss);
+			if (LOG.isLoggable(INFO)) LOG.info(ID + ": Incoming connection");
+			return new KeyAgreementConnection(conn, ID);
+		}
+
+		@Override
+		public void close() {
+			tryToClose(ss);
+		}
+	}
+}

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

@@ -108,7 +108,7 @@ abstract class FilePlugin implements SimplexPlugin {
 		}
 	}
 
-	protected void createReaderFromFile(final File f) {
+	protected void createReaderFromFile(File f) {
 		if (!running) return;
 		ioExecutor.execute(new ReaderCreator(f));
 	}

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

@@ -1,7 +1,6 @@
 package org.briarproject.bramble.plugin.tcp;
 
 import org.briarproject.bramble.api.FormatException;
-import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementConnection;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
@@ -24,9 +23,8 @@ import java.net.SocketAddress;
 import java.net.UnknownHostException;
 import java.util.ArrayList;
 import java.util.Collections;
-import java.util.LinkedList;
+import java.util.Comparator;
 import java.util.List;
-import java.util.concurrent.Callable;
 import java.util.concurrent.Executor;
 import java.util.logging.Logger;
 
@@ -35,6 +33,7 @@ import static java.util.logging.Level.WARNING;
 import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.TRANSPORT_ID_LAN;
 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.PrivacyUtils.scrubSocketAddress;
 
@@ -44,8 +43,10 @@ class LanTcpPlugin extends TcpPlugin {
 	private static final Logger LOG =
 			Logger.getLogger(LanTcpPlugin.class.getName());
 
+	private static final LanAddressComparator ADDRESS_COMPARATOR =
+			new LanAddressComparator();
+
 	private static final int MAX_ADDRESSES = 4;
-	private static final String PROP_IP_PORTS = "ipPorts";
 	private static final String SEPARATOR = ",";
 
 	LanTcpPlugin(Executor ioExecutor, Backoff backoff,
@@ -64,26 +65,25 @@ class LanTcpPlugin extends TcpPlugin {
 		TransportProperties p = callback.getLocalProperties();
 		String oldIpPorts = p.get(PROP_IP_PORTS);
 		List<InetSocketAddress> olds = parseSocketAddresses(oldIpPorts);
-		List<InetSocketAddress> locals = new LinkedList<InetSocketAddress>();
+		List<InetSocketAddress> locals = new ArrayList<>();
 		for (InetAddress local : getLocalIpAddresses()) {
 			if (isAcceptableAddress(local)) {
 				// If this is the old address, try to use the same port
 				for (InetSocketAddress old : olds) {
-					if (old.getAddress().equals(local)) {
-						int port = old.getPort();
-						locals.add(0, new InetSocketAddress(local, port));
-					}
+					if (old.getAddress().equals(local))
+						locals.add(new InetSocketAddress(local, old.getPort()));
 				}
 				locals.add(new InetSocketAddress(local, 0));
 			}
 		}
+		Collections.sort(locals, ADDRESS_COMPARATOR);
 		return locals;
 	}
 
 	private List<InetSocketAddress> parseSocketAddresses(String ipPorts) {
 		if (StringUtils.isNullOrEmpty(ipPorts)) return Collections.emptyList();
 		String[] split = ipPorts.split(SEPARATOR);
-		List<InetSocketAddress> addresses = new ArrayList<InetSocketAddress>();
+		List<InetSocketAddress> addresses = new ArrayList<>();
 		for (String ipPort : split) {
 			InetSocketAddress a = parseSocketAddress(ipPort);
 			if (a != null) addresses.add(a);
@@ -96,7 +96,7 @@ class LanTcpPlugin extends TcpPlugin {
 		String ipPort = getIpPortString(a);
 		// Get the list of recently used addresses
 		String setting = callback.getSettings().get(PREF_LAN_IP_PORTS);
-		List<String> recent = new ArrayList<String>();
+		List<String> recent = new ArrayList<>();
 		if (!StringUtils.isNullOrEmpty(setting))
 			Collections.addAll(recent, setting.split(SEPARATOR));
 		// Is the address already in the list?
@@ -112,7 +112,7 @@ class LanTcpPlugin extends TcpPlugin {
 				recent = recent.subList(0, MAX_ADDRESSES);
 			setting = StringUtils.join(recent, SEPARATOR);
 			// Update the list of addresses shared with contacts
-			List<String> shared = new ArrayList<String>(recent);
+			List<String> shared = new ArrayList<>(recent);
 			Collections.sort(shared);
 			String property = StringUtils.join(shared, SEPARATOR);
 			TransportProperties properties = new TransportProperties();
@@ -126,9 +126,8 @@ class LanTcpPlugin extends TcpPlugin {
 	}
 
 	@Override
-	protected List<InetSocketAddress> getRemoteSocketAddresses(ContactId c) {
-		TransportProperties p = callback.getRemoteProperties().get(c);
-		if (p == null) return Collections.emptyList();
+	protected List<InetSocketAddress> getRemoteSocketAddresses(
+			TransportProperties p) {
 		return parseSocketAddresses(p.get(PROP_IP_PORTS));
 	}
 
@@ -155,17 +154,39 @@ class LanTcpPlugin extends TcpPlugin {
 	// Package access for testing
 	boolean addressesAreOnSameLan(byte[] localIp, byte[] remoteIp) {
 		// 10.0.0.0/8
-		if (localIp[0] == 10) return remoteIp[0] == 10;
+		if (isPrefix10(localIp)) return isPrefix10(remoteIp);
 		// 172.16.0.0/12
-		if (localIp[0] == (byte) 172 && (localIp[1] & 0xF0) == 16)
-			return remoteIp[0] == (byte) 172 && (remoteIp[1] & 0xF0) == 16;
+		if (isPrefix172(localIp)) return isPrefix172(remoteIp);
 		// 192.168.0.0/16
-		if (localIp[0] == (byte) 192 && localIp[1] == (byte) 168)
-			return remoteIp[0] == (byte) 192 && remoteIp[1] == (byte) 168;
+		if (isPrefix192(localIp)) return isPrefix192(remoteIp);
 		// Unrecognised prefix - may be compatible
 		return true;
 	}
 
+	private static boolean isPrefix10(byte[] ipv4) {
+		return ipv4[0] == 10;
+	}
+
+	private static boolean isPrefix172(byte[] ipv4) {
+		return ipv4[0] == (byte) 172 && (ipv4[1] & 0xF0) == 16;
+	}
+
+	private static boolean isPrefix192(byte[] ipv4) {
+		return ipv4[0] == (byte) 192 && ipv4[1] == (byte) 168;
+	}
+
+	// Returns the prefix length for an RFC 1918 address, or 0 for any other
+	// address
+	private static int getRfc1918PrefixLength(InetAddress addr) {
+		if (!(addr instanceof Inet4Address)) return 0;
+		if (!addr.isSiteLocalAddress()) return 0;
+		byte[] ipv4 = addr.getAddress();
+		if (isPrefix10(ipv4)) return 8;
+		if (isPrefix172(ipv4)) return 12;
+		if (isPrefix192(ipv4)) return 16;
+		return 0;
+	}
+
 	@Override
 	public boolean supportsKeyAgreement() {
 		return true;
@@ -202,7 +223,7 @@ class LanTcpPlugin extends TcpPlugin {
 
 	@Override
 	public DuplexTransportConnection createKeyAgreementConnection(
-			byte[] commitment, BdfList descriptor, long timeout) {
+			byte[] commitment, BdfList descriptor) {
 		if (!isRunning()) return null;
 		InetSocketAddress remote;
 		try {
@@ -261,18 +282,11 @@ class LanTcpPlugin extends TcpPlugin {
 		}
 
 		@Override
-		public Callable<KeyAgreementConnection> listen() {
-			return new Callable<KeyAgreementConnection>() {
-				@Override
-				public KeyAgreementConnection call() throws IOException {
-					Socket s = ss.accept();
-					if (LOG.isLoggable(INFO))
-						LOG.info(ID.getString() + ": Incoming connection");
-					return new KeyAgreementConnection(
-							new TcpTransportConnection(LanTcpPlugin.this, s),
-							ID);
-				}
-			};
+		public KeyAgreementConnection accept() throws IOException {
+			Socket s = ss.accept();
+			if (LOG.isLoggable(INFO)) LOG.info(ID + ": Incoming connection");
+			return new KeyAgreementConnection(new TcpTransportConnection(
+					LanTcpPlugin.this, s), ID);
 		}
 
 		@Override
@@ -284,4 +298,19 @@ class LanTcpPlugin extends TcpPlugin {
 			}
 		}
 	}
+
+	static class LanAddressComparator implements Comparator<InetSocketAddress> {
+
+		@Override
+		public int compare(InetSocketAddress a, InetSocketAddress b) {
+			// Prefer addresses with non-zero ports
+			int aPort = a.getPort(), bPort = b.getPort();
+			if (aPort > 0 && bPort == 0) return -1;
+			if (aPort == 0 && bPort > 0) return 1;
+			// Prefer addresses with longer RFC 1918 prefixes
+			int aPrefix = getRfc1918PrefixLength(a.getAddress());
+			int bPrefix = getRfc1918PrefixLength(b.getAddress());
+			return bPrefix - aPrefix;
+		}
+	}
 }

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

@@ -37,7 +37,7 @@ class PortMapperImpl implements PortMapper {
 	}
 
 	@Override
-	public MappingResult map(final int port) {
+	public MappingResult map(int port) {
 		if (!started.getAndSet(true)) start();
 		if (gateway == null) return null;
 		InetAddress internal = gateway.getLocalAddress();
@@ -50,12 +50,7 @@ class PortMapperImpl implements PortMapper {
 			succeeded = gateway.addPortMapping(port, port,
 					getHostAddress(internal), "TCP", "TCP");
 			if (succeeded) {
-				shutdownManager.addShutdownHook(new Runnable() {
-					@Override
-					public void run() {
-						deleteMapping(port);
-					}
-				});
+				shutdownManager.addShutdownHook(() -> deleteMapping(port));
 			}
 			String externalString = gateway.getExternalIPAddress();
 			if (LOG.isLoggable(INFO))
@@ -63,9 +58,7 @@ class PortMapperImpl implements PortMapper {
 						"External address " + scrubInetAddress(externalString));
 			if (externalString != null)
 				external = InetAddress.getByName(externalString);
-		} catch (IOException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		} catch (SAXException e) {
+		} catch (IOException | SAXException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 		}
 		return new MappingResult(internal, external, port, succeeded);
@@ -82,11 +75,7 @@ class PortMapperImpl implements PortMapper {
 		GatewayDiscover d = new GatewayDiscover();
 		try {
 			d.discover();
-		} catch (IOException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		} catch (SAXException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		} catch (ParserConfigurationException e) {
+		} catch (IOException | SAXException | ParserConfigurationException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 		}
 		gateway = d.getValidGateway();
@@ -97,9 +86,7 @@ class PortMapperImpl implements PortMapper {
 			gateway.deletePortMapping(port, "TCP");
 			if (LOG.isLoggable(INFO))
 				LOG.info("Deleted mapping for port " + port);
-		} catch (IOException e) {
-			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
-		} catch (SAXException e) {
+		} catch (IOException | SAXException e) {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 		}
 	}

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

@@ -1,7 +1,6 @@
 package org.briarproject.bramble.plugin.tcp;
 
 import org.briarproject.bramble.api.contact.ContactId;
-import org.briarproject.bramble.api.crypto.PseudoRandom;
 import org.briarproject.bramble.api.data.BdfList;
 import org.briarproject.bramble.api.keyagreement.KeyAgreementListener;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
@@ -10,6 +9,7 @@ import org.briarproject.bramble.api.plugin.Backoff;
 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.StringUtils;
 
 import java.io.IOException;
@@ -25,6 +25,8 @@ import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
 import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.logging.Logger;
@@ -67,11 +69,11 @@ abstract class TcpPlugin implements DuplexPlugin {
 	protected abstract void setLocalSocketAddress(InetSocketAddress a);
 
 	/**
-	 * Returns zero or more socket addresses for connecting to the given
-	 * contact.
+	 * Returns zero or more socket addresses for connecting to a contact with
+	 * the given transport properties.
 	 */
 	protected abstract List<InetSocketAddress> getRemoteSocketAddresses(
-			ContactId c);
+			TransportProperties p);
 
 	/**
 	 * Returns true if connections to the given address can be attempted.
@@ -108,41 +110,37 @@ abstract class TcpPlugin implements DuplexPlugin {
 	}
 
 	protected void bind() {
-		ioExecutor.execute(new Runnable() {
-			@Override
-			public void run() {
-				if (!running) return;
-				ServerSocket ss = null;
-				for (InetSocketAddress addr : getLocalSocketAddresses()) {
-					try {
-						ss = new ServerSocket();
-						ss.bind(addr);
-						break;
-					} catch (IOException e) {
-						if (LOG.isLoggable(INFO))
-							LOG.info("Failed to bind " +
-									scrubSocketAddress(addr));
-						tryToClose(ss);
-					}
-				}
-				if (ss == null || !ss.isBound()) {
-					LOG.info("Could not bind server socket");
-					return;
-				}
-				if (!running) {
+		ioExecutor.execute(() -> {
+			if (!running) return;
+			ServerSocket ss = null;
+			for (InetSocketAddress addr : getLocalSocketAddresses()) {
+				try {
+					ss = new ServerSocket();
+					ss.bind(addr);
+					break;
+				} catch (IOException e) {
+					if (LOG.isLoggable(INFO))
+						LOG.info("Failed to bind " + scrubSocketAddress(addr));
 					tryToClose(ss);
-					return;
 				}
-				socket = ss;
-				backoff.reset();
-				InetSocketAddress local =
-						(InetSocketAddress) ss.getLocalSocketAddress();
-				setLocalSocketAddress(local);
-				if (LOG.isLoggable(INFO))
-					LOG.info("Listening on " + scrubSocketAddress(local));
-				callback.transportEnabled();
-				acceptContactConnections();
 			}
+			if (ss == null || !ss.isBound()) {
+				LOG.info("Could not bind server socket");
+				return;
+			}
+			if (!running) {
+				tryToClose(ss);
+				return;
+			}
+			socket = ss;
+			backoff.reset();
+			InetSocketAddress local =
+					(InetSocketAddress) ss.getLocalSocketAddress();
+			setLocalSocketAddress(local);
+			if (LOG.isLoggable(INFO))
+				LOG.info("Listening on " + scrubSocketAddress(local));
+			callback.transportEnabled();
+			acceptContactConnections();
 		});
 	}
 
@@ -208,20 +206,21 @@ abstract class TcpPlugin implements DuplexPlugin {
 	public void poll(Collection<ContactId> connected) {
 		if (!isRunning()) return;
 		backoff.increment();
-		// TODO: Pass properties to connectAndCallBack()
-		for (ContactId c : callback.getRemoteProperties().keySet())
-			if (!connected.contains(c)) connectAndCallBack(c);
+		Map<ContactId, TransportProperties> remote =
+				callback.getRemoteProperties();
+		for (Entry<ContactId, TransportProperties> e : remote.entrySet()) {
+			ContactId c = e.getKey();
+			if (!connected.contains(c)) connectAndCallBack(c, e.getValue());
+		}
 	}
 
-	private void connectAndCallBack(final ContactId c) {
-		ioExecutor.execute(new Runnable() {
-			@Override
-			public void run() {
-				DuplexTransportConnection d = createConnection(c);
-				if (d != null) {
-					backoff.reset();
-					callback.outgoingConnectionCreated(c, d);
-				}
+	private void connectAndCallBack(ContactId c, TransportProperties p) {
+		ioExecutor.execute(() -> {
+			if (!isRunning()) return;
+			DuplexTransportConnection d = createConnection(p);
+			if (d != null) {
+				backoff.reset();
+				callback.outgoingConnectionCreated(c, d);
 			}
 		});
 	}
@@ -229,7 +228,12 @@ abstract class TcpPlugin implements DuplexPlugin {
 	@Override
 	public DuplexTransportConnection createConnection(ContactId c) {
 		if (!isRunning()) return null;
-		for (InetSocketAddress remote : getRemoteSocketAddresses(c)) {
+		return createConnection(callback.getRemoteProperties(c));
+	}
+
+	@Nullable
+	private DuplexTransportConnection createConnection(TransportProperties p) {
+		for (InetSocketAddress remote : getRemoteSocketAddresses(p)) {
 			if (!isConnectable(remote)) {
 				if (LOG.isLoggable(INFO)) {
 					SocketAddress local = socket.getLocalSocketAddress();
@@ -281,17 +285,6 @@ abstract class TcpPlugin implements DuplexPlugin {
 		}
 	}
 
-	@Override
-	public boolean supportsInvitations() {
-		return false;
-	}
-
-	@Override
-	public DuplexTransportConnection createInvitationConnection(PseudoRandom r,
-			long timeout, boolean alice) {
-		throw new UnsupportedOperationException();
-	}
-
 	@Override
 	public boolean supportsKeyAgreement() {
 		return false;
@@ -304,7 +297,7 @@ abstract class TcpPlugin implements DuplexPlugin {
 
 	@Override
 	public DuplexTransportConnection createKeyAgreementConnection(
-			byte[] commitment, BdfList descriptor, long timeout) {
+			byte[] commitment, BdfList descriptor) {
 		throw new UnsupportedOperationException();
 	}
 
@@ -316,7 +309,7 @@ abstract class TcpPlugin implements DuplexPlugin {
 			if (LOG.isLoggable(WARNING)) LOG.log(WARNING, e.toString(), e);
 			return Collections.emptyList();
 		}
-		List<InetAddress> addrs = new ArrayList<InetAddress>();
+		List<InetAddress> addrs = new ArrayList<>();
 		for (NetworkInterface iface : ifaces)
 			addrs.addAll(Collections.list(iface.getInetAddresses()));
 		return addrs;