WIP add removabledrive test ui

Add RemovableDriveViewModel

See merge request briar/briar!1475

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

@@ -47,7 +47,7 @@ public class AndroidBluetoothPluginFactory implements DuplexPluginFactory {
 	private final BackoffFactory backoffFactory;
 
 	@Inject
-	public AndroidBluetoothPluginFactory(@IoExecutor Executor ioExecutor,
+	AndroidBluetoothPluginFactory(@IoExecutor Executor ioExecutor,
 			@WakefulIoExecutor Executor wakefulIoExecutor,
 			AndroidExecutor androidExecutor,
 			AndroidWakeLockManager wakeLockManager,

bramble-android/src/main/java/org/briarproject/bramble/plugin/file/AndroidRemovableDrivePlugin.java

@@ -0,0 +1,42 @@
+package org.briarproject.bramble.plugin.file;
+
+import android.app.Application;
+import android.net.Uri;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.properties.TransportProperties;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+import javax.annotation.concurrent.Immutable;
+
+import static org.briarproject.bramble.api.plugin.file.RemovableDriveConstants.PROP_URI;
+import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
+
+@Immutable
+@NotNullByDefault
+class AndroidRemovableDrivePlugin extends RemovableDrivePlugin {
+
+	private final Application app;
+
+	AndroidRemovableDrivePlugin(Application app, int maxLatency) {
+		super(maxLatency);
+		this.app = app;
+	}
+
+	@Override
+	InputStream openInputStream(TransportProperties p) throws IOException {
+		String uri = p.get(PROP_URI);
+		if (isNullOrEmpty(uri)) throw new IllegalArgumentException();
+		return app.getContentResolver().openInputStream(Uri.parse(uri));
+	}
+
+	@Override
+	OutputStream openOutputStream(TransportProperties p) throws IOException {
+		String uri = p.get(PROP_URI);
+		if (isNullOrEmpty(uri)) throw new IllegalArgumentException();
+		return app.getContentResolver().openOutputStream(Uri.parse(uri));
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/plugin/file/AndroidRemovableDrivePluginFactory.java

@@ -0,0 +1,47 @@
+package org.briarproject.bramble.plugin.file;
+
+import android.app.Application;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.PluginCallback;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
+import org.briarproject.bramble.api.plugin.simplex.SimplexPluginFactory;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.Immutable;
+import javax.inject.Inject;
+
+import static java.util.concurrent.TimeUnit.DAYS;
+import static org.briarproject.bramble.api.plugin.file.RemovableDriveConstants.ID;
+
+@Immutable
+@NotNullByDefault
+public class AndroidRemovableDrivePluginFactory implements
+		SimplexPluginFactory {
+
+	private static final int MAX_LATENCY = (int) DAYS.toMillis(14);
+
+	private final Application app;
+
+	@Inject
+	AndroidRemovableDrivePluginFactory(Application app) {
+		this.app = app;
+	}
+
+	@Override
+	public TransportId getId() {
+		return ID;
+	}
+
+	@Override
+	public int getMaxLatency() {
+		return MAX_LATENCY;
+	}
+
+	@Nullable
+	@Override
+	public SimplexPlugin createPlugin(PluginCallback callback) {
+		return new AndroidRemovableDrivePlugin(app, MAX_LATENCY);
+	}
+}

bramble-android/src/main/java/org/briarproject/bramble/plugin/tcp/AndroidLanTcpPluginFactory.java

@@ -37,7 +37,7 @@ public class AndroidLanTcpPluginFactory implements DuplexPluginFactory {
 	private final Application app;
 
 	@Inject
-	public AndroidLanTcpPluginFactory(@IoExecutor Executor ioExecutor,
+	AndroidLanTcpPluginFactory(@IoExecutor Executor ioExecutor,
 			@WakefulIoExecutor Executor wakefulIoExecutor,
 			EventBus eventBus,
 			BackoffFactory backoffFactory,

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

@@ -58,7 +58,7 @@ public class AndroidTorPluginFactory implements DuplexPluginFactory {
 	private final File torDirectory;
 
 	@Inject
-	public AndroidTorPluginFactory(@IoExecutor Executor ioExecutor,
+	AndroidTorPluginFactory(@IoExecutor Executor ioExecutor,
 			@WakefulIoExecutor Executor wakefulIoExecutor,
 			Application app,
 			NetworkManager networkManager,

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

@@ -0,0 +1,9 @@
+package org.briarproject.bramble.api;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+@NotNullByDefault
+public interface Consumer<T> {
+
+	void accept(T t);
+}

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

@@ -292,6 +292,16 @@ public interface DatabaseComponent extends TransactionManager {
 	 */
 	Message getMessage(Transaction txn, MessageId m) throws DbException;
 
+	/**
+	 * Returns the total length, including headers, of any messages that are
+	 * eligible to be sent to the given contact via a transport with the given
+	 * max latency.
+	 * <p/>
+	 * Read-only.
+	 */
+	long getMessageBytesToSend(Transaction txn, ContactId c, int maxLatency)
+			throws DbException;
+
 	/**
 	 * Returns the IDs of all delivered messages in the given group.
 	 * <p/>

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/file/FileConstants.java

@@ -1,4 +1,4 @@
-package org.briarproject.bramble.api.plugin;
+package org.briarproject.bramble.api.plugin.file;
 
 public interface FileConstants {
 

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/file/RemovableDriveConstants.java

@@ -0,0 +1,11 @@
+package org.briarproject.bramble.api.plugin.file;
+
+import org.briarproject.bramble.api.plugin.TransportId;
+
+public interface RemovableDriveConstants {
+
+	TransportId ID = new TransportId("org.briarproject.bramble.drive");
+
+	String PROP_PATH = "path";
+	String PROP_URI = "uri";
+}

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/file/RemovableDriveManager.java

@@ -0,0 +1,41 @@
+package org.briarproject.bramble.api.plugin.file;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.properties.TransportProperties;
+
+import javax.annotation.Nullable;
+
+@NotNullByDefault
+public interface RemovableDriveManager {
+
+	/**
+	 * Returns the currently running reader task for the given contact,
+	 * or null if no task is running.
+	 */
+	@Nullable
+	RemovableDriveTask getCurrentReaderTask(ContactId c);
+
+	/**
+	 * Returns the currently running writer task for the given contact,
+	 * or null if no task is running.
+	 */
+	@Nullable
+	RemovableDriveTask getCurrentWriterTask(ContactId c);
+
+	/**
+	 * Starts and returns a reader task for the given contact, reading from
+	 * a stream described by the given transport properties. If a reader task
+	 * for the contact is already running, it will be returned and the
+	 * transport properties will be ignored.
+	 */
+	RemovableDriveTask startReaderTask(ContactId c, TransportProperties p);
+
+	/**
+	 * Starts and returns a writer task for the given contact, writing to
+	 * a stream described by the given transport properties. If a writer task
+	 * for the contact is already running, it will be returned and the
+	 * transport properties will be ignored.
+	 */
+	RemovableDriveTask startWriterTask(ContactId c, TransportProperties p);
+}

bramble-api/src/main/java/org/briarproject/bramble/api/plugin/file/RemovableDriveTask.java

@@ -0,0 +1,65 @@
+package org.briarproject.bramble.api.plugin.file;
+
+import org.briarproject.bramble.api.Consumer;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.properties.TransportProperties;
+
+@NotNullByDefault
+public interface RemovableDriveTask extends Runnable {
+
+	/**
+	 * Returns the {@link TransportProperties} that were used for creating
+	 * this task.
+	 */
+	TransportProperties getTransportProperties();
+
+	/**
+	 * Adds an observer to the task. The observer will be notified of state
+	 * changes on the event thread. If the task has already finished, the
+	 * observer will be notified of its final state.
+	 */
+	void addObserver(Consumer<State> observer);
+
+	/**
+	 * Removes an observer from the task.
+	 */
+	void removeObserver(Consumer<State> observer);
+
+	class State {
+
+		private final long done, total;
+		private final boolean finished, success;
+
+		public State(long done, long total, boolean finished, boolean success) {
+			this.done = done;
+			this.total = total;
+			this.finished = finished;
+			this.success = success;
+		}
+
+		/**
+		 * Returns the total length in bytes of the messages read or written
+		 * so far.
+		 */
+		public long getDone() {
+			return done;
+		}
+
+		/**
+		 * Returns the total length in bytes of the messages that will have
+		 * been read or written when the task is complete, or zero if the
+		 * total is unknown.
+		 */
+		public long getTotal() {
+			return total;
+		}
+
+		public boolean isFinished() {
+			return finished;
+		}
+
+		public boolean isSuccess() {
+			return success;
+		}
+	}
+}

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

@@ -18,11 +18,13 @@ public class MessagesSentEvent extends Event {
 
 	private final ContactId contactId;
 	private final Collection<MessageId> messageIds;
+	private final long totalLength;
 
 	public MessagesSentEvent(ContactId contactId,
-			Collection<MessageId> messageIds) {
+			Collection<MessageId> messageIds, long totalLength) {
 		this.contactId = contactId;
 		this.messageIds = messageIds;
+		this.totalLength = totalLength;
 	}
 
 	public ContactId getContactId() {
@@ -32,4 +34,8 @@ public class MessagesSentEvent extends Event {
 	public Collection<MessageId> getMessageIds() {
 		return messageIds;
 	}
+
+	public long getTotalLength() {
+		return totalLength;
+	}
 }

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

@@ -347,6 +347,16 @@ interface Database<T> {
 	 */
 	Message getMessage(T txn, MessageId m) throws DbException;
 
+	/**
+	 * Returns the total length, including headers, of any messages that are
+	 * eligible to be sent to the given contact via a transport with the given
+	 * max latency.
+	 * <p/>
+	 * Read-only.
+	 */
+	long getMessageBytesToSend(T txn, ContactId c, int maxLatency)
+			throws DbException;
+
 	/**
 	 * Returns the IDs and states of all dependencies of the given message.
 	 * For missing dependencies and dependencies in other groups, the state

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

@@ -415,14 +415,17 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			throw new NoSuchContactException();
 		Collection<MessageId> ids =
 				db.getMessagesToSend(txn, c, maxLength, maxLatency);
+		long totalLength = 0;
 		List<Message> messages = new ArrayList<>(ids.size());
 		for (MessageId m : ids) {
-			messages.add(db.getMessage(txn, m));
+			Message message = db.getMessage(txn, m);
+			totalLength += message.getRawLength();
+			messages.add(message);
 			db.updateExpiryTimeAndEta(txn, c, m, maxLatency);
 		}
 		if (ids.isEmpty()) return null;
 		db.lowerRequestedFlag(txn, c, ids);
-		transaction.attach(new MessagesSentEvent(c, ids));
+		transaction.attach(new MessagesSentEvent(c, ids, totalLength));
 		return messages;
 	}
 
@@ -467,14 +470,17 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 			throw new NoSuchContactException();
 		Collection<MessageId> ids =
 				db.getRequestedMessagesToSend(txn, c, maxLength, maxLatency);
+		long totalLength = 0;
 		List<Message> messages = new ArrayList<>(ids.size());
 		for (MessageId m : ids) {
-			messages.add(db.getMessage(txn, m));
+			Message message = db.getMessage(txn, m);
+			totalLength += message.getRawLength();
+			messages.add(message);
 			db.updateExpiryTimeAndEta(txn, c, m, maxLatency);
 		}
 		if (ids.isEmpty()) return null;
 		db.lowerRequestedFlag(txn, c, ids);
-		transaction.attach(new MessagesSentEvent(c, ids));
+		transaction.attach(new MessagesSentEvent(c, ids, totalLength));
 		return messages;
 	}
 
@@ -569,6 +575,15 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return db.getMessage(txn, m);
 	}
 
+	@Override
+	public long getMessageBytesToSend(Transaction transaction, ContactId c,
+			int maxLatency) throws DbException {
+		T txn = unbox(transaction);
+		if (!db.containsContact(txn, c))
+			throw new NoSuchContactException();
+		return db.getMessageBytesToSend(txn, c, maxLatency);
+	}
+
 	@Override
 	public Collection<MessageId> getMessageIds(Transaction transaction,
 			GroupId g) throws DbException {

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

@@ -1758,6 +1758,37 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
+	@Override
+	public long getMessageBytesToSend(Connection txn, ContactId c,
+			int maxLatency) throws DbException {
+		long now = clock.currentTimeMillis();
+		long eta = now + maxLatency;
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT SUM(length) FROM statuses"
+					+ " WHERE contactId = ? AND state = ?"
+					+ " AND groupShared = TRUE AND messageShared = TRUE"
+					+ " AND deleted = FALSE AND seen = FALSE"
+					+ " AND (expiry <= ? OR eta > ?)";
+			ps = txn.prepareStatement(sql);
+			ps.setInt(1, c.getInt());
+			ps.setInt(2, DELIVERED.getValue());
+			ps.setLong(3, now);
+			ps.setLong(4, eta);
+			rs = ps.executeQuery();
+			rs.next();
+			long total = rs.getInt(1);
+			rs.close();
+			ps.close();
+			return total;
+		} catch (SQLException e) {
+			tryToClose(rs, LOG, WARNING);
+			tryToClose(ps, LOG, WARNING);
+			throw new DbException(e);
+		}
+	}
+
 	@Override
 	public Collection<MessageId> getMessageIds(Connection txn, GroupId g)
 			throws DbException {

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

@@ -0,0 +1,114 @@
+package org.briarproject.bramble.plugin.file;
+
+import org.briarproject.bramble.api.Pair;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.ConnectionHandler;
+import org.briarproject.bramble.api.plugin.TransportConnectionReader;
+import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
+import org.briarproject.bramble.api.properties.TransportProperties;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.util.Collection;
+import java.util.logging.Logger;
+
+import javax.annotation.concurrent.Immutable;
+
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
+import static org.briarproject.bramble.api.plugin.file.RemovableDriveConstants.ID;
+import static org.briarproject.bramble.util.LogUtils.logException;
+
+@Immutable
+@NotNullByDefault
+abstract class AbstractRemovableDrivePlugin implements SimplexPlugin {
+
+	private static final Logger LOG =
+			getLogger(AbstractRemovableDrivePlugin.class.getName());
+
+	private final int maxLatency;
+
+	abstract InputStream openInputStream(TransportProperties p)
+			throws IOException;
+
+	abstract OutputStream openOutputStream(TransportProperties p)
+			throws IOException;
+
+	AbstractRemovableDrivePlugin(int maxLatency) {
+		this.maxLatency = maxLatency;
+	}
+
+	@Override
+	public TransportId getId() {
+		return ID;
+	}
+
+	@Override
+	public int getMaxLatency() {
+		return maxLatency;
+	}
+
+	@Override
+	public int getMaxIdleTime() {
+		// Unused for simplex transports
+		throw new UnsupportedOperationException();
+	}
+
+	@Override
+	public void start() {
+	}
+
+	@Override
+	public void stop() {
+	}
+
+	@Override
+	public State getState() {
+		return ACTIVE;
+	}
+
+	@Override
+	public int getReasonsDisabled() {
+		return 0;
+	}
+
+	@Override
+	public boolean shouldPoll() {
+		return false;
+	}
+
+	@Override
+	public int getPollingInterval() {
+		throw new UnsupportedOperationException();
+	}
+
+	@Override
+	public void poll(
+			Collection<Pair<TransportProperties, ConnectionHandler>> properties) {
+		throw new UnsupportedOperationException();
+	}
+
+	@Override
+	public TransportConnectionReader createReader(TransportProperties p) {
+		try {
+			return new TransportInputStreamReader(openInputStream(p));
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+			return null;
+		}
+	}
+
+	@Override
+	public TransportConnectionWriter createWriter(TransportProperties p) {
+		try {
+			return new TransportOutputStreamWriter(this, openOutputStream(p));
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+			return null;
+		}
+	}
+}

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

@@ -15,8 +15,8 @@ import java.util.logging.Logger;
 
 import static java.util.logging.Level.WARNING;
 import static java.util.logging.Logger.getLogger;
-import static org.briarproject.bramble.api.plugin.FileConstants.PROP_PATH;
 import static org.briarproject.bramble.api.plugin.Plugin.State.ACTIVE;
+import static org.briarproject.bramble.api.plugin.file.FileConstants.PROP_PATH;
 import static org.briarproject.bramble.util.LogUtils.logException;
 import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
 

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

@@ -0,0 +1,83 @@
+package org.briarproject.bramble.plugin.file;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.lifecycle.IoExecutor;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.file.RemovableDriveManager;
+import org.briarproject.bramble.api.plugin.file.RemovableDriveTask;
+import org.briarproject.bramble.api.properties.TransportProperties;
+
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.Executor;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.ThreadSafe;
+import javax.inject.Inject;
+
+@ThreadSafe
+@NotNullByDefault
+class RemovableDriveManagerImpl
+		implements RemovableDriveManager, RemovableDriveTaskRegistry {
+
+	private final Executor ioExecutor;
+	private final RemovableDriveTaskFactory taskFactory;
+	private final ConcurrentHashMap<ContactId, RemovableDriveTask>
+			readers = new ConcurrentHashMap<>();
+	private final ConcurrentHashMap<ContactId, RemovableDriveTask>
+			writers = new ConcurrentHashMap<>();
+
+	@Inject
+	RemovableDriveManagerImpl(@IoExecutor Executor ioExecutor,
+			RemovableDriveTaskFactory taskFactory) {
+		this.ioExecutor = ioExecutor;
+		this.taskFactory = taskFactory;
+	}
+
+	@Nullable
+	@Override
+	public RemovableDriveTask getCurrentReaderTask(ContactId c) {
+		return readers.get(c);
+	}
+
+	@Nullable
+	@Override
+	public RemovableDriveTask getCurrentWriterTask(ContactId c) {
+		return writers.get(c);
+	}
+
+	@Override
+	public RemovableDriveTask startReaderTask(ContactId c,
+			TransportProperties p) {
+		RemovableDriveTask task = taskFactory.createReader(this, c, p);
+		RemovableDriveTask old = readers.putIfAbsent(c, task);
+		if (old == null) {
+			ioExecutor.execute(task);
+			return task;
+		} else {
+			return old;
+		}
+	}
+
+	@Override
+	public RemovableDriveTask startWriterTask(ContactId c,
+			TransportProperties p) {
+		RemovableDriveTask task = taskFactory.createWriter(this, c, p);
+		RemovableDriveTask old = writers.putIfAbsent(c, task);
+		if (old == null) {
+			ioExecutor.execute(task);
+			return task;
+		} else {
+			return old;
+		}
+	}
+
+	@Override
+	public void removeReader(ContactId c, RemovableDriveTask task) {
+		readers.remove(c, task);
+	}
+
+	@Override
+	public void removeWriter(ContactId c, RemovableDriveTask task) {
+		writers.remove(c, task);
+	}
+}

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

@@ -0,0 +1,25 @@
+package org.briarproject.bramble.plugin.file;
+
+import org.briarproject.bramble.api.plugin.file.RemovableDriveManager;
+
+import javax.inject.Singleton;
+
+import dagger.Module;
+import dagger.Provides;
+
+@Module
+public class RemovableDriveModule {
+
+	@Provides
+	@Singleton
+	RemovableDriveManager provideRemovableDriveManager(
+			RemovableDriveManagerImpl removableDriveManager) {
+		return removableDriveManager;
+	}
+
+	@Provides
+	RemovableDriveTaskFactory provideTaskFactory(
+			RemovableDriveTaskFactoryImpl taskFactory) {
+		return taskFactory;
+	}
+}

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

@@ -0,0 +1,38 @@
+package org.briarproject.bramble.plugin.file;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.properties.TransportProperties;
+
+import java.io.FileInputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+import javax.annotation.concurrent.Immutable;
+
+import static org.briarproject.bramble.api.plugin.file.RemovableDriveConstants.PROP_PATH;
+import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
+
+@Immutable
+@NotNullByDefault
+class RemovableDrivePlugin extends AbstractRemovableDrivePlugin {
+
+	RemovableDrivePlugin(int maxLatency) {
+		super(maxLatency);
+	}
+
+	@Override
+	InputStream openInputStream(TransportProperties p) throws IOException {
+		String path = p.get(PROP_PATH);
+		if (isNullOrEmpty(path)) throw new IllegalArgumentException();
+		return new FileInputStream(path);
+	}
+
+	@Override
+	OutputStream openOutputStream(TransportProperties p) throws IOException {
+		String path = p.get(PROP_PATH);
+		if (isNullOrEmpty(path)) throw new IllegalArgumentException();
+		return new FileOutputStream(path);
+	}
+}

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

@@ -0,0 +1,41 @@
+package org.briarproject.bramble.plugin.file;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.PluginCallback;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
+import org.briarproject.bramble.api.plugin.simplex.SimplexPluginFactory;
+
+import javax.annotation.Nullable;
+import javax.annotation.concurrent.Immutable;
+import javax.inject.Inject;
+
+import static java.util.concurrent.TimeUnit.DAYS;
+import static org.briarproject.bramble.api.plugin.file.RemovableDriveConstants.ID;
+
+@Immutable
+@NotNullByDefault
+public class RemovableDrivePluginFactory implements SimplexPluginFactory {
+
+	private static final int MAX_LATENCY = (int) DAYS.toMillis(14);
+
+	@Inject
+	RemovableDrivePluginFactory() {
+	}
+
+	@Override
+	public TransportId getId() {
+		return ID;
+	}
+
+	@Override
+	public int getMaxLatency() {
+		return MAX_LATENCY;
+	}
+
+	@Nullable
+	@Override
+	public SimplexPlugin createPlugin(PluginCallback callback) {
+		return new RemovableDrivePlugin(MAX_LATENCY);
+	}
+}

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

@@ -0,0 +1,88 @@
+package org.briarproject.bramble.plugin.file;
+
+import org.briarproject.bramble.api.connection.ConnectionManager;
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventListener;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.PluginManager;
+import org.briarproject.bramble.api.plugin.TransportConnectionReader;
+import org.briarproject.bramble.api.properties.TransportProperties;
+import org.briarproject.bramble.api.sync.event.MessageAddedEvent;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.api.plugin.file.RemovableDriveConstants.ID;
+
+@NotNullByDefault
+class RemovableDriveReaderTask extends RemovableDriveTaskImpl
+		implements EventListener {
+
+	private final static Logger LOG =
+			getLogger(RemovableDriveReaderTask.class.getName());
+
+	RemovableDriveReaderTask(
+			Executor eventExecutor,
+			PluginManager pluginManager,
+			ConnectionManager connectionManager,
+			EventBus eventBus,
+			RemovableDriveTaskRegistry registry,
+			ContactId contactId,
+			TransportProperties transportProperties) {
+		super(eventExecutor, pluginManager, connectionManager, eventBus,
+				registry, contactId, transportProperties);
+	}
+
+	@Override
+	public void run() {
+		TransportConnectionReader r =
+				getPlugin().createReader(transportProperties);
+		if (r == null) {
+			LOG.warning("Failed to create reader");
+			registry.removeReader(contactId, this);
+			setSuccess(false);
+			return;
+		}
+		eventBus.addListener(this);
+		connectionManager.manageIncomingConnection(ID, new DecoratedReader(r));
+	}
+
+	@Override
+	public void eventOccurred(Event e) {
+		if (e instanceof MessageAddedEvent) {
+			MessageAddedEvent m = (MessageAddedEvent) e;
+			if (contactId.equals(m.getContactId())) {
+				LOG.info("Message received");
+				addDone(m.getMessage().getRawLength());
+			}
+		}
+	}
+
+	private class DecoratedReader implements TransportConnectionReader {
+
+		private final TransportConnectionReader delegate;
+
+		private DecoratedReader(TransportConnectionReader delegate) {
+			this.delegate = delegate;
+		}
+
+		@Override
+		public InputStream getInputStream() throws IOException {
+			return delegate.getInputStream();
+		}
+
+		@Override
+		public void dispose(boolean exception, boolean recognised)
+				throws IOException {
+			delegate.dispose(exception, recognised);
+			registry.removeReader(contactId, RemovableDriveReaderTask.this);
+			eventBus.removeListener(RemovableDriveReaderTask.this);
+			setSuccess(!exception && recognised);
+		}
+	}
+}

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

@@ -0,0 +1,16 @@
+package org.briarproject.bramble.plugin.file;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.file.RemovableDriveTask;
+import org.briarproject.bramble.api.properties.TransportProperties;
+
+@NotNullByDefault
+interface RemovableDriveTaskFactory {
+
+	RemovableDriveTask createReader(RemovableDriveTaskRegistry registry,
+			ContactId c, TransportProperties p);
+
+	RemovableDriveTask createWriter(RemovableDriveTaskRegistry registry,
+			ContactId c, TransportProperties p);
+}

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

@@ -0,0 +1,55 @@
+package org.briarproject.bramble.plugin.file;
+
+import org.briarproject.bramble.api.connection.ConnectionManager;
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventExecutor;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.PluginManager;
+import org.briarproject.bramble.api.plugin.file.RemovableDriveTask;
+import org.briarproject.bramble.api.properties.TransportProperties;
+
+import java.util.concurrent.Executor;
+
+import javax.annotation.concurrent.Immutable;
+import javax.inject.Inject;
+
+@Immutable
+@NotNullByDefault
+class RemovableDriveTaskFactoryImpl implements RemovableDriveTaskFactory {
+
+	private final DatabaseComponent db;
+	private final Executor eventExecutor;
+	private final PluginManager pluginManager;
+	private final ConnectionManager connectionManager;
+	private final EventBus eventBus;
+
+	@Inject
+	RemovableDriveTaskFactoryImpl(
+			DatabaseComponent db,
+			@EventExecutor Executor eventExecutor,
+			PluginManager pluginManager,
+			ConnectionManager connectionManager,
+			EventBus eventBus) {
+		this.db = db;
+		this.eventExecutor = eventExecutor;
+		this.pluginManager = pluginManager;
+		this.connectionManager = connectionManager;
+		this.eventBus = eventBus;
+	}
+
+	@Override
+	public RemovableDriveTask createReader(RemovableDriveTaskRegistry registry,
+			ContactId c, TransportProperties p) {
+		return new RemovableDriveReaderTask(eventExecutor, pluginManager,
+				connectionManager, eventBus, registry, c, p);
+	}
+
+	@Override
+	public RemovableDriveTask createWriter(RemovableDriveTaskRegistry registry,
+			ContactId c, TransportProperties p) {
+		return new RemovableDriveWriterTask(db, eventExecutor, pluginManager,
+				connectionManager, eventBus, registry, c, p);
+	}
+}

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

@@ -0,0 +1,120 @@
+package org.briarproject.bramble.plugin.file;
+
+import org.briarproject.bramble.api.Consumer;
+import org.briarproject.bramble.api.connection.ConnectionManager;
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.PluginManager;
+import org.briarproject.bramble.api.plugin.file.RemovableDriveTask;
+import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
+import org.briarproject.bramble.api.properties.TransportProperties;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.concurrent.Executor;
+
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+
+import static java.lang.Math.min;
+import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
+import static org.briarproject.bramble.api.plugin.file.RemovableDriveConstants.ID;
+
+@ThreadSafe
+@NotNullByDefault
+abstract class RemovableDriveTaskImpl implements RemovableDriveTask {
+
+	private final Executor eventExecutor;
+	private final PluginManager pluginManager;
+	final ConnectionManager connectionManager;
+	final EventBus eventBus;
+	final RemovableDriveTaskRegistry registry;
+	final ContactId contactId;
+	final TransportProperties transportProperties;
+
+	private final Object lock = new Object();
+	@GuardedBy("lock")
+	private final List<Consumer<State>> observers = new ArrayList<>();
+	@GuardedBy("lock")
+	private State state = new State(0, 0, false, false);
+
+	RemovableDriveTaskImpl(
+			Executor eventExecutor,
+			PluginManager pluginManager,
+			ConnectionManager connectionManager,
+			EventBus eventBus,
+			RemovableDriveTaskRegistry registry,
+			ContactId contactId,
+			TransportProperties transportProperties) {
+		this.eventExecutor = eventExecutor;
+		this.pluginManager = pluginManager;
+		this.connectionManager = connectionManager;
+		this.eventBus = eventBus;
+		this.registry = registry;
+		this.contactId = contactId;
+		this.transportProperties = transportProperties;
+	}
+
+	@Override
+	public TransportProperties getTransportProperties() {
+		return transportProperties;
+	}
+
+	@Override
+	public void addObserver(Consumer<State> o) {
+		State state;
+		synchronized (lock) {
+			observers.add(o);
+			state = this.state;
+		}
+		if (state.isFinished()) {
+			eventExecutor.execute(() -> o.accept(state));
+		}
+	}
+
+	@Override
+	public void removeObserver(Consumer<State> o) {
+		synchronized (lock) {
+			observers.remove(o);
+		}
+	}
+
+	SimplexPlugin getPlugin() {
+		return (SimplexPlugin) requireNonNull(pluginManager.getPlugin(ID));
+	}
+
+	void setTotal(long total) {
+		synchronized (lock) {
+			state = new State(state.getDone(), total, state.isFinished(),
+					state.isSuccess());
+			notifyObservers();
+		}
+	}
+
+	void addDone(long done) {
+		synchronized (lock) {
+			// Done and total come from different sources; make them consistent
+			done = min(state.getDone() + done, state.getTotal());
+			state = new State(done, state.getTotal(), state.isFinished(),
+					state.isSuccess());
+		}
+		notifyObservers();
+	}
+
+	void setSuccess(boolean success) {
+		synchronized (lock) {
+			state = new State(state.getDone(), state.getTotal(), true, success);
+		}
+		notifyObservers();
+	}
+
+	@GuardedBy("lock")
+	private void notifyObservers() {
+		List<Consumer<State>> observers = new ArrayList<>(this.observers);
+		State state = this.state;
+		eventExecutor.execute(() -> {
+			for (Consumer<State> o : observers) o.accept(state);
+		});
+	}
+}

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

@@ -0,0 +1,13 @@
+package org.briarproject.bramble.plugin.file;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.file.RemovableDriveTask;
+
+@NotNullByDefault
+interface RemovableDriveTaskRegistry {
+
+	void removeReader(ContactId c, RemovableDriveTask task);
+
+	void removeWriter(ContactId c, RemovableDriveTask task);
+}

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

@@ -0,0 +1,120 @@
+package org.briarproject.bramble.plugin.file;
+
+import org.briarproject.bramble.api.connection.ConnectionManager;
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.db.DatabaseComponent;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.event.EventListener;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.PluginManager;
+import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
+import org.briarproject.bramble.api.plugin.simplex.SimplexPlugin;
+import org.briarproject.bramble.api.properties.TransportProperties;
+import org.briarproject.bramble.api.sync.event.MessagesSentEvent;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import static java.util.logging.Level.INFO;
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.api.plugin.file.RemovableDriveConstants.ID;
+import static org.briarproject.bramble.util.LogUtils.logException;
+
+@NotNullByDefault
+class RemovableDriveWriterTask extends RemovableDriveTaskImpl
+		implements EventListener {
+
+	private static final Logger LOG =
+			getLogger(RemovableDriveWriterTask.class.getName());
+
+	private final DatabaseComponent db;
+
+	RemovableDriveWriterTask(
+			DatabaseComponent db,
+			Executor eventExecutor,
+			PluginManager pluginManager,
+			ConnectionManager connectionManager,
+			EventBus eventBus,
+			RemovableDriveTaskRegistry registry,
+			ContactId contactId,
+			TransportProperties transportProperties) {
+		super(eventExecutor, pluginManager, connectionManager, eventBus,
+				registry, contactId, transportProperties);
+		this.db = db;
+	}
+
+	@Override
+	public void run() {
+		SimplexPlugin plugin = getPlugin();
+		TransportConnectionWriter w = plugin.createWriter(transportProperties);
+		if (w == null) {
+			LOG.warning("Failed to create writer");
+			registry.removeWriter(contactId, this);
+			setSuccess(false);
+			return;
+		}
+		int maxLatency = plugin.getMaxLatency();
+		try {
+			setTotal(db.transactionWithResult(true, txn ->
+					db.getMessageBytesToSend(txn, contactId, maxLatency)));
+		} catch (DbException e) {
+			logException(LOG, WARNING, e);
+			registry.removeWriter(contactId, this);
+			setSuccess(false);
+			return;
+		}
+		eventBus.addListener(this);
+		connectionManager.manageOutgoingConnection(contactId, ID,
+				new DecoratedWriter(w));
+	}
+
+	@Override
+	public void eventOccurred(Event e) {
+		if (e instanceof MessagesSentEvent) {
+			MessagesSentEvent m = (MessagesSentEvent) e;
+			if (contactId.equals(m.getContactId())) {
+				if (LOG.isLoggable(INFO)) {
+					LOG.info(m.getMessageIds().size() + " messages sent");
+				}
+				addDone(m.getTotalLength());
+			}
+		}
+	}
+
+	private class DecoratedWriter implements TransportConnectionWriter {
+
+		private final TransportConnectionWriter delegate;
+
+		private DecoratedWriter(TransportConnectionWriter delegate) {
+			this.delegate = delegate;
+		}
+
+		@Override
+		public int getMaxLatency() {
+			return delegate.getMaxLatency();
+		}
+
+		@Override
+		public int getMaxIdleTime() {
+			return delegate.getMaxIdleTime();
+		}
+
+		@Override
+		public OutputStream getOutputStream() throws IOException {
+			return delegate.getOutputStream();
+		}
+
+		@Override
+		public void dispose(boolean exception) throws IOException {
+			delegate.dispose(exception);
+			registry.removeWriter(contactId, RemovableDriveWriterTask.this);
+			eventBus.removeListener(RemovableDriveWriterTask.this);
+			setSuccess(!exception);
+		}
+	}
+}

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

@@ -0,0 +1,34 @@
+package org.briarproject.bramble.plugin.file;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.TransportConnectionReader;
+
+import java.io.InputStream;
+import java.util.logging.Logger;
+
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.IoUtils.tryToClose;
+
+@NotNullByDefault
+class TransportInputStreamReader implements TransportConnectionReader {
+
+	private static final Logger LOG =
+			getLogger(TransportInputStreamReader.class.getName());
+
+	private final InputStream in;
+
+	TransportInputStreamReader(InputStream in) {
+		this.in = in;
+	}
+
+	@Override
+	public InputStream getInputStream() {
+		return in;
+	}
+
+	@Override
+	public void dispose(boolean exception, boolean recognised) {
+		tryToClose(in, LOG, WARNING);
+	}
+}

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

@@ -0,0 +1,47 @@
+package org.briarproject.bramble.plugin.file;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.Plugin;
+import org.briarproject.bramble.api.plugin.TransportConnectionWriter;
+
+import java.io.OutputStream;
+import java.util.logging.Logger;
+
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.IoUtils.tryToClose;
+
+@NotNullByDefault
+class TransportOutputStreamWriter implements TransportConnectionWriter {
+
+	private static final Logger LOG =
+			getLogger(TransportOutputStreamWriter.class.getName());
+
+	private final Plugin plugin;
+	private final OutputStream out;
+
+	TransportOutputStreamWriter(Plugin plugin, OutputStream out) {
+		this.plugin = plugin;
+		this.out = out;
+	}
+
+	@Override
+	public int getMaxLatency() {
+		return plugin.getMaxLatency();
+	}
+
+	@Override
+	public int getMaxIdleTime() {
+		return plugin.getMaxIdleTime();
+	}
+
+	@Override
+	public OutputStream getOutputStream() {
+		return out;
+	}
+
+	@Override
+	public void dispose(boolean exception) {
+		tryToClose(out, LOG, WARNING);
+	}
+}

bramble-core/src/test/java/org/briarproject/bramble/db/DatabaseComponentImplTest.java

@@ -298,11 +298,11 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			throws Exception {
 		context.checking(new Expectations() {{
 			// Check whether the contact is in the DB (which it's not)
-			exactly(18).of(database).startTransaction();
+			exactly(19).of(database).startTransaction();
 			will(returnValue(txn));
-			exactly(18).of(database).containsContact(txn, contactId);
+			exactly(19).of(database).containsContact(txn, contactId);
 			will(returnValue(false));
-			exactly(18).of(database).abortTransaction(txn);
+			exactly(19).of(database).abortTransaction(txn);
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
 				eventExecutor, shutdownManager);
@@ -349,7 +349,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		}
 
 		try {
-			db.transaction(false, transaction ->
+			db.transaction(true, transaction ->
 					db.getContact(transaction, contactId));
 			fail();
 		} catch (NoSuchContactException expected) {
@@ -357,7 +357,15 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		}
 
 		try {
-			db.transaction(false, transaction ->
+			db.transaction(true, transaction ->
+					db.getMessageBytesToSend(transaction, contactId, 123));
+			fail();
+		} catch (NoSuchContactException expected) {
+			// Expected
+		}
+
+		try {
+			db.transaction(true, transaction ->
 					db.getMessageStatus(transaction, contactId, groupId));
 			fail();
 		} catch (NoSuchContactException expected) {
@@ -365,7 +373,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		}
 
 		try {
-			db.transaction(false, transaction ->
+			db.transaction(true, transaction ->
 					db.getMessageStatus(transaction, contactId, messageId));
 			fail();
 		} catch (NoSuchContactException expected) {
@@ -373,7 +381,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		}
 
 		try {
-			db.transaction(false, transaction ->
+			db.transaction(true, transaction ->
 					db.getGroupVisibility(transaction, contactId, groupId));
 			fail();
 		} catch (NoSuchContactException expected) {
@@ -381,7 +389,7 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		}
 
 		try {
-			db.transaction(false, transaction ->
+			db.transaction(true, transaction ->
 					db.getSyncVersions(transaction, contactId));
 			fail();
 		} catch (NoSuchContactException expected) {

bramble-core/src/test/java/org/briarproject/bramble/db/JdbcDatabaseTest.java

@@ -227,6 +227,8 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		assertEquals(singletonList(messageId), ids);
 		ids = db.getMessagesToOffer(txn, contactId, 100, MAX_LATENCY);
 		assertEquals(singletonList(messageId), ids);
+		assertEquals(message.getRawLength(),
+				db.getMessageBytesToSend(txn, contactId, MAX_LATENCY));
 
 		// Changing the status to seen = true should make the message unsendable
 		db.raiseSeenFlag(txn, contactId, messageId);
@@ -234,6 +236,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		assertTrue(ids.isEmpty());
 		ids = db.getMessagesToOffer(txn, contactId, 100, MAX_LATENCY);
 		assertTrue(ids.isEmpty());
+		assertEquals(0, db.getMessageBytesToSend(txn, contactId, MAX_LATENCY));
 
 		db.commitTransaction(txn);
 		db.close();
@@ -258,6 +261,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		assertTrue(ids.isEmpty());
 		ids = db.getMessagesToOffer(txn, contactId, 100, MAX_LATENCY);
 		assertTrue(ids.isEmpty());
+		assertEquals(0, db.getMessageBytesToSend(txn, contactId, MAX_LATENCY));
 
 		// Marking the message delivered should make it sendable
 		db.setMessageState(txn, messageId, DELIVERED);
@@ -265,6 +269,8 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		assertEquals(singletonList(messageId), ids);
 		ids = db.getMessagesToOffer(txn, contactId, 100, MAX_LATENCY);
 		assertEquals(singletonList(messageId), ids);
+		assertEquals(message.getRawLength(),
+				db.getMessageBytesToSend(txn, contactId, MAX_LATENCY));
 
 		// Marking the message invalid should make it unsendable
 		db.setMessageState(txn, messageId, INVALID);
@@ -272,6 +278,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		assertTrue(ids.isEmpty());
 		ids = db.getMessagesToOffer(txn, contactId, 100, MAX_LATENCY);
 		assertTrue(ids.isEmpty());
+		assertEquals(0, db.getMessageBytesToSend(txn, contactId, MAX_LATENCY));
 
 		// Marking the message pending should make it unsendable
 		db.setMessageState(txn, messageId, PENDING);
@@ -279,6 +286,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		assertTrue(ids.isEmpty());
 		ids = db.getMessagesToOffer(txn, contactId, 100, MAX_LATENCY);
 		assertTrue(ids.isEmpty());
+		assertEquals(0, db.getMessageBytesToSend(txn, contactId, MAX_LATENCY));
 
 		db.commitTransaction(txn);
 		db.close();
@@ -302,6 +310,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		assertTrue(ids.isEmpty());
 		ids = db.getMessagesToOffer(txn, contactId, 100, MAX_LATENCY);
 		assertTrue(ids.isEmpty());
+		assertEquals(0, db.getMessageBytesToSend(txn, contactId, MAX_LATENCY));
 
 		// Making the group visible should not make the message sendable
 		db.addGroupVisibility(txn, contactId, groupId, false);
@@ -309,6 +318,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		assertTrue(ids.isEmpty());
 		ids = db.getMessagesToOffer(txn, contactId, 100, MAX_LATENCY);
 		assertTrue(ids.isEmpty());
+		assertEquals(0, db.getMessageBytesToSend(txn, contactId, MAX_LATENCY));
 
 		// Sharing the group should make the message sendable
 		db.setGroupVisibility(txn, contactId, groupId, true);
@@ -316,6 +326,8 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		assertEquals(singletonList(messageId), ids);
 		ids = db.getMessagesToOffer(txn, contactId, 100, MAX_LATENCY);
 		assertEquals(singletonList(messageId), ids);
+		assertEquals(message.getRawLength(),
+				db.getMessageBytesToSend(txn, contactId, MAX_LATENCY));
 
 		// Unsharing the group should make the message unsendable
 		db.setGroupVisibility(txn, contactId, groupId, false);
@@ -323,6 +335,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		assertTrue(ids.isEmpty());
 		ids = db.getMessagesToOffer(txn, contactId, 100, MAX_LATENCY);
 		assertTrue(ids.isEmpty());
+		assertEquals(0, db.getMessageBytesToSend(txn, contactId, MAX_LATENCY));
 
 		// Making the group invisible should make the message unsendable
 		db.removeGroupVisibility(txn, contactId, groupId);
@@ -330,6 +343,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		assertTrue(ids.isEmpty());
 		ids = db.getMessagesToOffer(txn, contactId, 100, MAX_LATENCY);
 		assertTrue(ids.isEmpty());
+		assertEquals(0, db.getMessageBytesToSend(txn, contactId, MAX_LATENCY));
 
 		db.commitTransaction(txn);
 		db.close();
@@ -354,6 +368,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		assertTrue(ids.isEmpty());
 		ids = db.getMessagesToOffer(txn, contactId, 100, MAX_LATENCY);
 		assertTrue(ids.isEmpty());
+		assertEquals(0, db.getMessageBytesToSend(txn, contactId, MAX_LATENCY));
 
 		// Sharing the message should make it sendable
 		db.setMessageShared(txn, messageId, true);
@@ -361,6 +376,8 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		assertEquals(singletonList(messageId), ids);
 		ids = db.getMessagesToOffer(txn, contactId, 100, MAX_LATENCY);
 		assertEquals(singletonList(messageId), ids);
+		assertEquals(message.getRawLength(),
+				db.getMessageBytesToSend(txn, contactId, MAX_LATENCY));
 
 		db.commitTransaction(txn);
 		db.close();
@@ -384,10 +401,15 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 				db.getMessagesToSend(txn, contactId, message.getRawLength() - 1,
 						MAX_LATENCY);
 		assertTrue(ids.isEmpty());
+		assertEquals(message.getRawLength(),
+				db.getMessageBytesToSend(txn, contactId, MAX_LATENCY));
+
 		// The message is just the right size to send
 		ids = db.getMessagesToSend(txn, contactId, message.getRawLength(),
 				MAX_LATENCY);
 		assertEquals(singletonList(messageId), ids);
+		assertEquals(message.getRawLength(),
+				db.getMessageBytesToSend(txn, contactId, MAX_LATENCY));
 
 		db.commitTransaction(txn);
 		db.close();

bramble-core/src/test/java/org/briarproject/bramble/plugin/file/RemovableDriveIntegrationTest.java

@@ -0,0 +1,168 @@
+package org.briarproject.bramble.plugin.file;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.contact.ContactManager;
+import org.briarproject.bramble.api.crypto.SecretKey;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.event.EventListener;
+import org.briarproject.bramble.api.identity.Author;
+import org.briarproject.bramble.api.identity.Identity;
+import org.briarproject.bramble.api.identity.IdentityManager;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.file.RemovableDriveTask;
+import org.briarproject.bramble.api.properties.TransportProperties;
+import org.briarproject.bramble.api.sync.event.MessageStateChangedEvent;
+import org.briarproject.bramble.test.BrambleTestCase;
+import org.briarproject.bramble.test.TestDatabaseConfigModule;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.File;
+import java.util.concurrent.CountDownLatch;
+
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+import static org.briarproject.bramble.api.plugin.file.FileConstants.PROP_PATH;
+import static org.briarproject.bramble.api.sync.validation.MessageState.DELIVERED;
+import static org.briarproject.bramble.test.TestUtils.deleteTestDirectory;
+import static org.briarproject.bramble.test.TestUtils.getSecretKey;
+import static org.briarproject.bramble.test.TestUtils.getTestDirectory;
+import static org.junit.Assert.assertTrue;
+
+public class RemovableDriveIntegrationTest extends BrambleTestCase {
+
+	private static final int TIMEOUT_MS = 5_000;
+
+	private final File testDir = getTestDirectory();
+	private final File aliceDir = new File(testDir, "alice");
+	private final File bobDir = new File(testDir, "bob");
+
+	private final SecretKey rootKey = getSecretKey();
+	private final long timestamp = System.currentTimeMillis();
+
+	private RemovableDriveIntegrationTestComponent alice, bob;
+
+	@Before
+	public void setUp() {
+		assertTrue(testDir.mkdirs());
+		alice = DaggerRemovableDriveIntegrationTestComponent.builder()
+				.testDatabaseConfigModule(
+						new TestDatabaseConfigModule(aliceDir)).build();
+		RemovableDriveIntegrationTestComponent.Helper
+				.injectEagerSingletons(alice);
+		bob = DaggerRemovableDriveIntegrationTestComponent.builder()
+				.testDatabaseConfigModule(
+						new TestDatabaseConfigModule(bobDir)).build();
+		RemovableDriveIntegrationTestComponent.Helper
+				.injectEagerSingletons(bob);
+	}
+
+	@Test
+	public void testWriteAndRead() throws Exception {
+		// Create the identities
+		Identity aliceIdentity =
+				alice.getIdentityManager().createIdentity("Alice");
+		Identity bobIdentity = bob.getIdentityManager().createIdentity("Bob");
+		// Set up the devices and get the contact IDs
+		ContactId bobId = setUp(alice, aliceIdentity,
+				bobIdentity.getLocalAuthor(), true);
+		ContactId aliceId = setUp(bob, bobIdentity,
+				aliceIdentity.getLocalAuthor(), false);
+		// Sync Alice's client versions and transport properties
+		read(bob, aliceId, write(alice, bobId), 2);
+		// Sync Bob's client versions and transport properties
+		read(alice, bobId, write(bob, aliceId), 2);
+	}
+
+	private ContactId setUp(RemovableDriveIntegrationTestComponent device,
+			Identity local, Author remote, boolean alice) throws Exception {
+		// Add an identity for the user
+		IdentityManager identityManager = device.getIdentityManager();
+		identityManager.registerIdentity(local);
+		// Start the lifecycle manager
+		LifecycleManager lifecycleManager = device.getLifecycleManager();
+		lifecycleManager.startServices(getSecretKey());
+		lifecycleManager.waitForStartup();
+		// Add the other user as a contact
+		ContactManager contactManager = device.getContactManager();
+		return contactManager.addContact(remote, local.getId(), rootKey,
+				timestamp, alice, true, true);
+	}
+
+	@SuppressWarnings("SameParameterValue")
+	private void read(RemovableDriveIntegrationTestComponent device,
+			ContactId contactId, File file, int deliveries) throws Exception {
+		// Listen for message deliveries
+		MessageDeliveryListener listener =
+				new MessageDeliveryListener(deliveries);
+		device.getEventBus().addListener(listener);
+		// Read the incoming stream
+		TransportProperties p = new TransportProperties();
+		p.put(PROP_PATH, file.getAbsolutePath());
+		RemovableDriveTask reader = device.getRemovableDriveManager()
+				.startReaderTask(contactId, p);
+		CountDownLatch disposedLatch = new CountDownLatch(1);
+		reader.addObserver(state -> {
+			if (state.isFinished()) disposedLatch.countDown();
+		});
+		// Wait for the messages to be delivered
+		assertTrue(listener.delivered.await(TIMEOUT_MS, MILLISECONDS));
+		// Clean up the listener
+		device.getEventBus().removeListener(listener);
+		// Wait for the reader to be disposed
+		disposedLatch.await(TIMEOUT_MS, MILLISECONDS);
+	}
+
+	private File write(RemovableDriveIntegrationTestComponent device,
+			ContactId contactId) throws Exception {
+		// Write the outgoing stream to a file
+		File file = File.createTempFile("sync", ".tmp", testDir);
+		TransportProperties p = new TransportProperties();
+		p.put(PROP_PATH, file.getAbsolutePath());
+		RemovableDriveTask writer = device.getRemovableDriveManager()
+				.startWriterTask(contactId, p);
+		CountDownLatch disposedLatch = new CountDownLatch(1);
+		writer.addObserver(state -> {
+			if (state.isFinished()) disposedLatch.countDown();
+		});
+		// Wait for the writer to be disposed
+		disposedLatch.await(TIMEOUT_MS, MILLISECONDS);
+		// Return the file containing the stream
+		return file;
+	}
+
+	private void tearDown(RemovableDriveIntegrationTestComponent device)
+			throws Exception {
+		// Stop the lifecycle manager
+		LifecycleManager lifecycleManager = device.getLifecycleManager();
+		lifecycleManager.stopServices();
+		lifecycleManager.waitForShutdown();
+	}
+
+	@After
+	public void tearDown() throws Exception {
+		// Tear down the devices
+		tearDown(alice);
+		tearDown(bob);
+		deleteTestDirectory(testDir);
+	}
+
+	@NotNullByDefault
+	private static class MessageDeliveryListener implements EventListener {
+
+		private final CountDownLatch delivered;
+
+		private MessageDeliveryListener(int deliveries) {
+			delivered = new CountDownLatch(deliveries);
+		}
+
+		@Override
+		public void eventOccurred(Event e) {
+			if (e instanceof MessageStateChangedEvent) {
+				MessageStateChangedEvent m = (MessageStateChangedEvent) e;
+				if (m.getState().equals(DELIVERED)) delivered.countDown();
+			}
+		}
+	}
+}

bramble-core/src/test/java/org/briarproject/bramble/plugin/file/RemovableDriveIntegrationTestComponent.java

@@ -0,0 +1,53 @@
+package org.briarproject.bramble.plugin.file;
+
+import org.briarproject.bramble.BrambleCoreEagerSingletons;
+import org.briarproject.bramble.BrambleCoreModule;
+import org.briarproject.bramble.api.contact.ContactManager;
+import org.briarproject.bramble.api.event.EventBus;
+import org.briarproject.bramble.api.identity.IdentityManager;
+import org.briarproject.bramble.api.lifecycle.LifecycleManager;
+import org.briarproject.bramble.api.plugin.file.RemovableDriveManager;
+import org.briarproject.bramble.battery.DefaultBatteryManagerModule;
+import org.briarproject.bramble.event.DefaultEventExecutorModule;
+import org.briarproject.bramble.system.DefaultWakefulIoExecutorModule;
+import org.briarproject.bramble.system.TimeTravelModule;
+import org.briarproject.bramble.test.TestDatabaseConfigModule;
+import org.briarproject.bramble.test.TestSecureRandomModule;
+
+import javax.inject.Singleton;
+
+import dagger.Component;
+
+@Singleton
+@Component(modules = {
+		BrambleCoreModule.class,
+		DefaultBatteryManagerModule.class,
+		DefaultEventExecutorModule.class,
+		DefaultWakefulIoExecutorModule.class,
+		TestDatabaseConfigModule.class,
+		RemovableDriveIntegrationTestModule.class,
+		RemovableDriveModule.class,
+		TestSecureRandomModule.class,
+		TimeTravelModule.class
+})
+interface RemovableDriveIntegrationTestComponent
+		extends BrambleCoreEagerSingletons {
+
+	ContactManager getContactManager();
+
+	EventBus getEventBus();
+
+	IdentityManager getIdentityManager();
+
+	LifecycleManager getLifecycleManager();
+
+	RemovableDriveManager getRemovableDriveManager();
+
+	class Helper {
+
+		public static void injectEagerSingletons(
+				RemovableDriveIntegrationTestComponent c) {
+			BrambleCoreEagerSingletons.Helper.injectEagerSingletons(c);
+		}
+	}
+}

bramble-core/src/test/java/org/briarproject/bramble/plugin/file/RemovableDriveIntegrationTestModule.java

@@ -1,61 +1,81 @@
-package org.briarproject.bramble.plugin;
+package org.briarproject.bramble.plugin.file;
 
+import org.briarproject.bramble.api.FeatureFlags;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.bramble.api.plugin.BluetoothConstants;
-import org.briarproject.bramble.api.plugin.LanTcpConstants;
 import org.briarproject.bramble.api.plugin.PluginConfig;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.plugin.duplex.DuplexPluginFactory;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPluginFactory;
-import org.briarproject.bramble.plugin.bluetooth.JavaBluetoothPluginFactory;
-import org.briarproject.bramble.plugin.modem.ModemPluginFactory;
-import org.briarproject.bramble.plugin.tcp.LanTcpPluginFactory;
-import org.briarproject.bramble.plugin.tcp.WanTcpPluginFactory;
 
 import java.util.Collection;
 import java.util.List;
 import java.util.Map;
 
+import javax.inject.Singleton;
+
 import dagger.Module;
 import dagger.Provides;
 
-import static java.util.Arrays.asList;
 import static java.util.Collections.emptyList;
+import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonList;
-import static java.util.Collections.singletonMap;
 
 @Module
-public class DesktopPluginModule extends PluginModule {
+class RemovableDriveIntegrationTestModule {
 
 	@Provides
-	PluginConfig getPluginConfig(JavaBluetoothPluginFactory bluetooth,
-			ModemPluginFactory modem, LanTcpPluginFactory lan,
-			WanTcpPluginFactory wan) {
+	@Singleton
+	PluginConfig providePluginConfig(RemovableDrivePluginFactory drive) {
 		@NotNullByDefault
 		PluginConfig pluginConfig = new PluginConfig() {
 
 			@Override
 			public Collection<DuplexPluginFactory> getDuplexFactories() {
-				return asList(bluetooth, modem, lan, wan);
-			}
-
-			@Override
-			public Collection<SimplexPluginFactory> getSimplexFactories() {
 				return emptyList();
 			}
 
+			@Override
+			public Collection<SimplexPluginFactory> getSimplexFactories() {
+				return singletonList(drive);
+			}
+
 			@Override
 			public boolean shouldPoll() {
-				return true;
+				return false;
 			}
 
 			@Override
 			public Map<TransportId, List<TransportId>> getTransportPreferences() {
-				// Prefer LAN to Bluetooth
-				return singletonMap(BluetoothConstants.ID,
-						singletonList(LanTcpConstants.ID));
+				return emptyMap();
 			}
+
 		};
 		return pluginConfig;
 	}
+
+	@Provides
+	FeatureFlags provideFeatureFlags() {
+		return new FeatureFlags() {
+
+			@Override
+			public boolean shouldEnableImageAttachments() {
+				return true;
+			}
+
+			@Override
+			public boolean shouldEnableProfilePictures() {
+				return true;
+			}
+
+			@Override
+			public boolean shouldEnableDisappearingMessages() {
+				return true;
+			}
+
+			@Override
+			public boolean shouldEnableConnectViaBluetooth() {
+				return true;
+			}
+		};
+	}
 }

bramble-java/src/main/java/org/briarproject/bramble/plugin/tor/UnixTorPluginFactory.java

@@ -55,7 +55,7 @@ public class UnixTorPluginFactory implements DuplexPluginFactory {
 	private final File torDirectory;
 
 	@Inject
-	public UnixTorPluginFactory(@IoExecutor Executor ioExecutor,
+	UnixTorPluginFactory(@IoExecutor Executor ioExecutor,
 			@IoExecutor Executor wakefulIoExecutor,
 			NetworkManager networkManager,
 			LocationUtils locationUtils,

briar-android/src/main/AndroidManifest.xml

@@ -437,6 +437,15 @@
 				android:value="org.briarproject.briar.android.navdrawer.NavDrawerActivity" />
 		</activity>
 
+		<activity
+			android:name="org.briarproject.briar.android.removabledrive.RemovableDriveActivity"
+			android:label="TODO Removable Drive"
+			android:parentActivityName="org.briarproject.briar.android.conversation.ConversationActivity">
+			<meta-data
+				android:name="android.support.PARENT_ACTIVITY"
+				android:value="org.briarproject.briar.android.conversation.ConversationActivity" />
+		</activity>
+
 		<activity
 			android:name=".android.contact.add.remote.PendingContactListActivity"
 			android:label="@string/pending_contact_requests"

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

@@ -28,6 +28,7 @@ import org.briarproject.bramble.api.system.AndroidExecutor;
 import org.briarproject.bramble.api.system.AndroidWakeLockManager;
 import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.system.LocationUtils;
+import org.briarproject.bramble.plugin.file.RemovableDriveModule;
 import org.briarproject.bramble.plugin.tor.CircumventionProvider;
 import org.briarproject.bramble.system.ClockModule;
 import org.briarproject.briar.BriarCoreEagerSingletons;
@@ -83,7 +84,8 @@ import dagger.Component;
 		AppModule.class,
 		AttachmentModule.class,
 		ClockModule.class,
-		MediaModule.class
+		MediaModule.class,
+		RemovableDriveModule.class
 })
 public interface AndroidComponent
 		extends BrambleCoreEagerSingletons, BrambleAndroidEagerSingletons,

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

@@ -24,6 +24,8 @@ import org.briarproject.bramble.api.plugin.duplex.DuplexPluginFactory;
 import org.briarproject.bramble.api.plugin.simplex.SimplexPluginFactory;
 import org.briarproject.bramble.api.reporting.DevConfig;
 import org.briarproject.bramble.plugin.bluetooth.AndroidBluetoothPluginFactory;
+import org.briarproject.bramble.plugin.file.AndroidRemovableDrivePluginFactory;
+import org.briarproject.bramble.plugin.file.RemovableDriveModule;
 import org.briarproject.bramble.plugin.tcp.AndroidLanTcpPluginFactory;
 import org.briarproject.bramble.plugin.tor.AndroidTorPluginFactory;
 import org.briarproject.bramble.util.AndroidUtils;
@@ -67,7 +69,6 @@ import dagger.Provides;
 import static android.content.Context.MODE_PRIVATE;
 import static android.os.Build.VERSION.SDK_INT;
 import static java.util.Arrays.asList;
-import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
 import static java.util.Collections.singletonMap;
 import static org.briarproject.bramble.api.reporting.ReportingConstants.DEV_ONION_ADDRESS;
@@ -92,6 +93,7 @@ import static org.briarproject.briar.android.TestingConstants.IS_DEBUG_BUILD;
 		GroupListModule.class,
 		GroupConversationModule.class,
 		SharingModule.class,
+		RemovableDriveModule.class
 })
 public class AppModule {
 
@@ -149,8 +151,10 @@ public class AppModule {
 	}
 
 	@Provides
+	@Singleton
 	PluginConfig providePluginConfig(AndroidBluetoothPluginFactory bluetooth,
-			AndroidTorPluginFactory tor, AndroidLanTcpPluginFactory lan) {
+			AndroidTorPluginFactory tor, AndroidLanTcpPluginFactory lan,
+			AndroidRemovableDrivePluginFactory drive) {
 		@NotNullByDefault
 		PluginConfig pluginConfig = new PluginConfig() {
 
@@ -161,7 +165,7 @@ public class AppModule {
 
 			@Override
 			public Collection<SimplexPluginFactory> getSimplexFactories() {
-				return emptyList();
+				return singletonList(drive);
 			}
 
 			@Override

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

@@ -63,6 +63,7 @@ import org.briarproject.briar.android.privategroup.memberlist.GroupMemberModule;
 import org.briarproject.briar.android.privategroup.reveal.GroupRevealModule;
 import org.briarproject.briar.android.privategroup.reveal.RevealContactsActivity;
 import org.briarproject.briar.android.privategroup.reveal.RevealContactsFragment;
+import org.briarproject.briar.android.removabledrive.RemovableDriveActivity;
 import org.briarproject.briar.android.reporting.CrashFragment;
 import org.briarproject.briar.android.reporting.CrashReportActivity;
 import org.briarproject.briar.android.reporting.ReportFormFragment;
@@ -176,6 +177,8 @@ public interface ActivityComponent {
 
 	void inject(CrashReportActivity crashReportActivity);
 
+	void inject(RemovableDriveActivity activity);
+
 	// Fragments
 
 	void inject(SetupFragment fragment);

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

@@ -14,5 +14,7 @@ public interface RequestCodes {
 	int REQUEST_ATTACH_IMAGE = 13;
 	int REQUEST_SAVE_ATTACHMENT = 14;
 	int REQUEST_AVATAR_IMAGE = 15;
+	int REQUEST_REMOVABLE_DRIVE_WRITE = 16;
+	int REQUEST_REMOVABLE_DRIVE_READ = 17;
 
 }

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationActivity.java

@@ -34,7 +34,6 @@ import org.briarproject.bramble.api.event.EventBus;
 import org.briarproject.bramble.api.event.EventListener;
 import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
 import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
-import org.briarproject.bramble.api.plugin.BluetoothConstants;
 import org.briarproject.bramble.api.plugin.event.ContactConnectedEvent;
 import org.briarproject.bramble.api.plugin.event.ContactDisconnectedEvent;
 import org.briarproject.bramble.api.sync.ClientId;
@@ -54,6 +53,7 @@ import org.briarproject.briar.android.forum.ForumActivity;
 import org.briarproject.briar.android.fragment.BaseFragment.BaseFragmentListener;
 import org.briarproject.briar.android.introduction.IntroductionActivity;
 import org.briarproject.briar.android.privategroup.conversation.GroupActivity;
+import org.briarproject.briar.android.removabledrive.RemovableDriveActivity;
 import org.briarproject.briar.android.util.BriarSnackbarBuilder;
 import org.briarproject.briar.android.view.BriarRecyclerView;
 import org.briarproject.briar.android.view.ImagePreview;
@@ -421,6 +421,11 @@ public class ConversationActivity extends BriarActivity
 		} else if (itemId == R.id.action_social_remove_person) {
 			askToRemoveContact();
 			return true;
+		} else if (itemId == R.id.action_removable_drive_write) {
+			Intent intent = new Intent(this, RemovableDriveActivity.class);
+			intent.putExtra(CONTACT_ID, contactId.getInt());
+			startActivity(intent);
+			return true;
 		}
 		return super.onOptionsItemSelected(item);
 	}

briar-android/src/main/java/org/briarproject/briar/android/removabledrive/RemovableDriveActivity.java

@@ -0,0 +1,174 @@
+package org.briarproject.briar.android.removabledrive;
+
+import android.content.Intent;
+import android.net.Uri;
+import android.os.Bundle;
+import android.view.MenuItem;
+import android.widget.Button;
+import android.widget.TextView;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.bramble.api.plugin.file.RemovableDriveTask.State;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.ActivityComponent;
+import org.briarproject.briar.android.activity.BriarActivity;
+import org.briarproject.briar.android.fragment.BaseFragment.BaseFragmentListener;
+
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.Locale;
+
+import javax.inject.Inject;
+
+import androidx.activity.result.ActivityResultLauncher;
+import androidx.activity.result.contract.ActivityResultContracts;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.annotation.RequiresApi;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.ViewModelProvider;
+
+import static org.briarproject.briar.android.conversation.ConversationActivity.CONTACT_ID;
+
+// TODO 19 will be our requirement for sneakernet support, right. The file apis
+//  used require this.
+@RequiresApi(api = 19)
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+public class RemovableDriveActivity extends BriarActivity
+		implements BaseFragmentListener {
+
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+	private RemovableDriveViewModel viewModel;
+	private TextView text;
+	private Button writeButton;
+	private Button readButton;
+
+	@Override
+	public void injectActivity(ActivityComponent component) {
+		component.inject(this);
+
+		viewModel = new ViewModelProvider(this, viewModelFactory)
+				.get(RemovableDriveViewModel.class);
+	}
+
+	@Override
+	public void onCreate(@Nullable Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+		setContentView(R.layout.activity_removable_drive);
+		text = findViewById(R.id.sneaker_text);
+		writeButton = findViewById(R.id.sneaker_write);
+		readButton = findViewById(R.id.sneaker_read);
+
+		Intent intent = getIntent();
+		int contactId = intent.getIntExtra(CONTACT_ID, -1);
+		if (contactId == -1) {
+			writeButton.setEnabled(false);
+			readButton.setEnabled(false);
+			return;
+		}
+
+		// TODO we can pass an extra named DocumentsContract.EXTRA_INITIAL_URI
+		//  to have the filepicker start on the usb-stick -- if get hold of URI
+		//  of the same. USB manager API?
+		//  Overall, passing this extra requires extending the ready-made
+		//  contracts and overriding createIntent.
+
+		writeButton.setText("Write for contactId " + contactId);
+		ActivityResultLauncher<String> createDocument =
+				registerForActivityResult(
+						new ActivityResultContracts.CreateDocument(),
+						uri -> write(contactId, uri));
+		writeButton.setOnClickListener(
+				v -> createDocument.launch(viewModel.getFileName()));
+
+		readButton.setText("Read for contactId " + contactId);
+		ActivityResultLauncher<String> getContent =
+				registerForActivityResult(
+						new ActivityResultContracts.GetContent(),
+						uri -> read(contactId, uri));
+		readButton.setOnClickListener(
+				v -> getContent.launch("application/octet-stream"));
+
+		LiveData<State> state;
+		state = viewModel.ongoingWrite(new ContactId(contactId));
+		if (state == null) {
+			writeButton.setEnabled(true);
+		} else {
+			say("\nOngoing write:");
+			writeButton.setEnabled(false);
+			state.observe(this, (taskState) -> handleState("write", taskState));
+		}
+		state = viewModel.ongoingRead(new ContactId(contactId));
+		if (state == null) {
+			readButton.setEnabled(true);
+		} else {
+			say("\nOngoing read:");
+			readButton.setEnabled(false);
+			state.observe(this, (taskState) -> handleState("read", taskState));
+		}
+	}
+
+	@Override
+	public boolean onOptionsItemSelected(@NonNull MenuItem item) {
+		if (item.getItemId() == android.R.id.home) {
+			onBackPressed();
+			return true;
+		}
+		return super.onOptionsItemSelected(item);
+	}
+
+	private void write(int contactId, @Nullable Uri uri) {
+		if (contactId == -1) {
+			throw new IllegalStateException();
+		}
+		if (uri == null) {
+			say("no URI picked for write");
+			return;
+		}
+		say("\nWriting to URI: " + uri);
+		writeButton.setEnabled(false);
+		LiveData<State> state = viewModel.write(new ContactId(contactId), uri);
+		state.observe(this, (taskState) -> handleState("write", taskState));
+	}
+
+	private void read(int contactId, @Nullable Uri uri) {
+		if (contactId == -1) {
+			throw new IllegalStateException();
+		}
+		if (uri == null) {
+			say("no URI picked for read");
+			return;
+		}
+		say("\nReading from URI: " + uri);
+		readButton.setEnabled(false);
+		LiveData<State> state = viewModel.read(new ContactId(contactId), uri);
+		state.observe(this, (taskState) -> handleState("read", taskState));
+	}
+
+	private void handleState(String action, State taskState) {
+		say(String.format(Locale.getDefault(),
+				"%s: bytes done: %d of %d. %s. %s.",
+				action, taskState.getDone(), taskState.getTotal(),
+				taskState.isFinished() ? "Finished" : "Ongoing",
+				taskState.isFinished() ?
+						(taskState.isSuccess() ? "Success" : "Failed") : ".."));
+		if (taskState.isFinished()) {
+			if (action.equals("write")) {
+				writeButton.setEnabled(true);
+			} else if (action.equals("read")) {
+				readButton.setEnabled(true);
+			}
+		}
+	}
+
+	private void say(String txt) {
+		String time = new SimpleDateFormat("HH:mm:ss", Locale.getDefault())
+				.format(new Date());
+		txt = String.format("%s %s\n", time, txt);
+		text.setText(text.getText().toString().concat(txt));
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/removabledrive/RemovableDriveModule.java

@@ -0,0 +1,18 @@
+package org.briarproject.briar.android.removabledrive;
+
+import org.briarproject.briar.android.viewmodel.ViewModelKey;
+
+import androidx.lifecycle.ViewModel;
+import dagger.Binds;
+import dagger.Module;
+import dagger.multibindings.IntoMap;
+
+@Module
+public interface RemovableDriveModule {
+
+	@Binds
+	@IntoMap
+	@ViewModelKey(RemovableDriveViewModel.class)
+	ViewModel bindRemovableDriveViewModel(RemovableDriveViewModel removableDriveViewModel);
+
+}

briar-android/src/main/java/org/briarproject/briar/android/removabledrive/RemovableDriveViewModel.java

@@ -0,0 +1,101 @@
+package org.briarproject.briar.android.removabledrive;
+
+import android.app.Application;
+import android.net.Uri;
+
+import org.briarproject.bramble.api.Consumer;
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.plugin.file.RemovableDriveManager;
+import org.briarproject.bramble.api.plugin.file.RemovableDriveTask;
+import org.briarproject.bramble.api.plugin.file.RemovableDriveTask.State;
+import org.briarproject.bramble.api.properties.TransportProperties;
+
+import java.text.SimpleDateFormat;
+import java.util.Date;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.logging.Logger;
+
+import javax.annotation.Nullable;
+import javax.inject.Inject;
+
+import androidx.lifecycle.AndroidViewModel;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
+import static java.util.Locale.US;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.api.plugin.file.RemovableDriveConstants.PROP_URI;
+
+@NotNullByDefault
+class RemovableDriveViewModel extends AndroidViewModel {
+
+	private static final Logger LOG =
+			getLogger(RemovableDriveViewModel.class.getName());
+
+	private final RemovableDriveManager manager;
+
+	private final ConcurrentHashMap<Consumer<State>, RemovableDriveTask>
+			observers = new ConcurrentHashMap<>();
+
+	@Inject
+	RemovableDriveViewModel(Application app,
+			RemovableDriveManager removableDriveManager) {
+		super(app);
+
+		this.manager = removableDriveManager;
+	}
+
+	String getFileName() {
+		SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd_HHmmss_SSS", US);
+		return sdf.format(new Date());
+	}
+
+
+	LiveData<State> write(ContactId contactId, Uri uri) {
+		TransportProperties p = new TransportProperties();
+		p.put(PROP_URI, uri.toString());
+		return observe(manager.startWriterTask(contactId, p));
+	}
+
+	LiveData<State> read(ContactId contactId, Uri uri) {
+		TransportProperties p = new TransportProperties();
+		p.put(PROP_URI, uri.toString());
+		return observe(manager.startReaderTask(contactId, p));
+	}
+
+	@Nullable
+	LiveData<State> ongoingWrite(ContactId contactId) {
+		RemovableDriveTask task = manager.getCurrentWriterTask(contactId);
+		if (task == null) {
+			return null;
+		}
+		return observe(task);
+	}
+
+	@Nullable
+	LiveData<State> ongoingRead(ContactId contactId) {
+		RemovableDriveTask task = manager.getCurrentReaderTask(contactId);
+		if (task == null) {
+			return null;
+		}
+		return observe(task);
+	}
+
+	private LiveData<State> observe(RemovableDriveTask task) {
+		MutableLiveData<State> state = new MutableLiveData<>();
+		Consumer<State> observer = state::postValue;
+		task.addObserver(observer);
+		observers.put(observer, task);
+		return state;
+	}
+
+	@Override
+	protected void onCleared() {
+		for (Map.Entry<Consumer<State>, RemovableDriveTask> entry
+				: observers.entrySet()) {
+			entry.getValue().removeObserver(entry.getKey());
+		}
+	}
+}

briar-android/src/main/res/layout/activity_removable_drive.xml

@@ -0,0 +1,52 @@
+<?xml version="1.0" encoding="utf-8"?>
+<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
+	xmlns:app="http://schemas.android.com/apk/res-auto"
+	xmlns:tools="http://schemas.android.com/tools"
+	android:layout_width="match_parent"
+	android:layout_height="match_parent"
+	tools:context=".android.removabledrive.RemovableDriveActivity">
+
+	<androidx.constraintlayout.widget.ConstraintLayout
+		android:layout_width="match_parent"
+		android:layout_height="wrap_content"
+		android:padding="@dimen/margin_large">
+
+		<Button
+			android:id="@+id/sneaker_write"
+			style="@style/BriarButton"
+			android:layout_width="match_parent"
+			android:layout_height="wrap_content"
+			android:layout_marginTop="@dimen/margin_medium"
+			android:enabled="false"
+			android:text=""
+			app:layout_constraintLeft_toLeftOf="parent"
+			app:layout_constraintRight_toRightOf="parent"
+			app:layout_constraintTop_toTopOf="parent"
+			tools:enabled="true" />
+
+		<Button
+			android:id="@+id/sneaker_read"
+			style="@style/BriarButton"
+			android:layout_width="match_parent"
+			android:layout_height="wrap_content"
+			android:layout_marginTop="@dimen/margin_medium"
+			android:enabled="false"
+			android:text=""
+			app:layout_constraintLeft_toLeftOf="parent"
+			app:layout_constraintRight_toRightOf="parent"
+			app:layout_constraintTop_toBottomOf="@id/sneaker_write"
+			tools:enabled="true" />
+
+		<TextView
+			android:id="@+id/sneaker_text"
+			android:layout_width="wrap_content"
+			android:layout_height="wrap_content"
+			android:padding="@dimen/margin_large"
+			android:textSize="12sp"
+			app:layout_constraintLeft_toLeftOf="parent"
+			app:layout_constraintRight_toRightOf="parent"
+			app:layout_constraintTop_toBottomOf="@id/sneaker_read" />
+
+	</androidx.constraintlayout.widget.ConstraintLayout>
+
+</ScrollView>

briar-android/src/main/res/menu/conversation_actions.xml

@@ -40,4 +40,9 @@
 		android:title="@string/delete_contact"
 		app:showAsAction="never" />
 
+	<item
+		android:id="@+id/action_removable_drive_write"
+		android:title="Transfer via removable drive"
+		app:showAsAction="never" />
+
 </menu>

briar-headless/src/main/java/org/briarproject/briar/headless/HeadlessModule.kt

@@ -74,6 +74,7 @@ internal class HeadlessModule(private val appDir: File) {
     }
 
     @Provides
+    @Singleton
     internal fun providePluginConfig(tor: UnixTorPluginFactory): PluginConfig {
         val duplex: List<DuplexPluginFactory> =
             if (isLinux() || isMac()) listOf(tor) else emptyList()

briar-headless/src/test/java/org/briarproject/briar/headless/HeadlessTestModule.kt

@@ -64,6 +64,7 @@ internal class HeadlessTestModule(private val appDir: File) {
     }
 
     @Provides
+    @Singleton
     internal fun providePluginConfig(): PluginConfig {
         return object : PluginConfig {
             override fun getDuplexFactories(): Collection<DuplexPluginFactory> = emptyList()

briar-headless/src/test/java/org/briarproject/briar/headless/messaging/MessagingControllerImplTest.kt

@@ -136,7 +136,7 @@ internal class MessagingControllerImplTest : ControllerTest() {
         val messageId1 = MessageId(getRandomId())
         val messageId2 = MessageId(getRandomId())
         val messageIds = listOf(messageId1, messageId2)
-        val event = MessagesSentEvent(contact.id, messageIds)
+        val event = MessagesSentEvent(contact.id, messageIds, 1234)
 
         every {
             webSocketController.sendEvent(
@@ -274,7 +274,7 @@ internal class MessagingControllerImplTest : ControllerTest() {
         val messageId1 = MessageId(getRandomId())
         val messageId2 = MessageId(getRandomId())
         val messageIds = listOf(messageId1, messageId2)
-        val event = MessagesSentEvent(contact.id, messageIds)
+        val event = MessagesSentEvent(contact.id, messageIds, 1234)
 
         val json = """
             {