Added message queue manager.

briar-api/src/org/briarproject/api/clients/MessageQueueManager.java

@@ -0,0 +1,38 @@
+package org.briarproject.api.clients;
+
+import org.briarproject.api.db.DbException;
+import org.briarproject.api.db.Metadata;
+import org.briarproject.api.db.Transaction;
+import org.briarproject.api.sync.ClientId;
+import org.briarproject.api.sync.Group;
+
+public interface MessageQueueManager {
+
+	/**
+	 * The key used for storing the queue's state in the group metadata.
+	 */
+	String QUEUE_STATE_KEY = "queueState";
+
+	/**
+	 * Sends a message using the given queue.
+	 */
+	QueueMessage sendMessage(Transaction txn, Group queue, long timestamp,
+			byte[] body, Metadata meta) throws DbException;
+
+	/**
+	 * Sets the message validator for the given client.
+	 */
+	void registerMessageValidator(ClientId c, QueueMessageValidator v);
+
+	/**
+	 * Sets the incoming message hook for the given client. The hook will be
+	 * called once for each incoming message that passes validation. Messages
+	 * are passed to the hook in order.
+	 */
+	void registerIncomingMessageHook(ClientId c, IncomingQueueMessageHook hook);
+
+	interface IncomingQueueMessageHook {
+		void incomingMessage(Transaction txn, QueueMessage q, Metadata meta)
+				throws DbException;
+	}
+}

briar-api/src/org/briarproject/api/clients/QueueMessage.java

@@ -0,0 +1,28 @@
+package org.briarproject.api.clients;
+
+import org.briarproject.api.sync.GroupId;
+import org.briarproject.api.sync.Message;
+import org.briarproject.api.sync.MessageId;
+
+import static org.briarproject.api.sync.SyncConstants.MAX_MESSAGE_BODY_LENGTH;
+import static org.briarproject.api.sync.SyncConstants.MESSAGE_HEADER_LENGTH;
+
+public class QueueMessage extends Message {
+
+	public static final int QUEUE_MESSAGE_HEADER_LENGTH =
+			MESSAGE_HEADER_LENGTH + 8;
+	public static final int MAX_QUEUE_MESSAGE_BODY_LENGTH =
+			MAX_MESSAGE_BODY_LENGTH - 8;
+
+	private final long queuePosition;
+
+	public QueueMessage(MessageId id, GroupId groupId, long timestamp,
+			long queuePosition, byte[] raw) {
+		super(id, groupId, timestamp, raw);
+		this.queuePosition = queuePosition;
+	}
+
+	public long getQueuePosition() {
+		return queuePosition;
+	}
+}

briar-api/src/org/briarproject/api/clients/QueueMessageFactory.java

@@ -0,0 +1,12 @@
+package org.briarproject.api.clients;
+
+import org.briarproject.api.sync.GroupId;
+import org.briarproject.api.sync.MessageId;
+
+public interface QueueMessageFactory {
+
+	QueueMessage createMessage(GroupId groupId, long timestamp,
+			long queuePosition, byte[] body);
+
+	QueueMessage createMessage(MessageId id, byte[] raw);
+}

briar-api/src/org/briarproject/api/clients/QueueMessageValidator.java

@@ -0,0 +1,13 @@
+package org.briarproject.api.clients;
+
+import org.briarproject.api.db.Metadata;
+import org.briarproject.api.sync.Group;
+
+public interface QueueMessageValidator {
+
+	/**
+	 * Validates the given message and returns its metadata if the message
+	 * is valid, or null if the message is invalid.
+	 */
+	Metadata validateMessage(QueueMessage q, Group g);
+}

briar-core/src/org/briarproject/clients/ClientsModule.java

@@ -3,13 +3,17 @@ package org.briarproject.clients;
 import com.google.inject.AbstractModule;
 
 import org.briarproject.api.clients.ClientHelper;
+import org.briarproject.api.clients.MessageQueueManager;
 import org.briarproject.api.clients.PrivateGroupFactory;
+import org.briarproject.api.clients.QueueMessageFactory;
 
 public class ClientsModule extends AbstractModule {
 
 	@Override
 	protected void configure() {
 		bind(ClientHelper.class).to(ClientHelperImpl.class);
+		bind(MessageQueueManager.class).to(MessageQueueManagerImpl.class);
 		bind(PrivateGroupFactory.class).to(PrivateGroupFactoryImpl.class);
+		bind(QueueMessageFactory.class).to(QueueMessageFactoryImpl.class);
 	}
 }

briar-core/src/org/briarproject/clients/MessageQueueManagerImpl.java

@@ -0,0 +1,211 @@
+package org.briarproject.clients;
+
+import org.briarproject.api.FormatException;
+import org.briarproject.api.clients.ClientHelper;
+import org.briarproject.api.clients.MessageQueueManager;
+import org.briarproject.api.clients.QueueMessage;
+import org.briarproject.api.clients.QueueMessageFactory;
+import org.briarproject.api.clients.QueueMessageValidator;
+import org.briarproject.api.data.BdfDictionary;
+import org.briarproject.api.data.BdfList;
+import org.briarproject.api.db.DatabaseComponent;
+import org.briarproject.api.db.DbException;
+import org.briarproject.api.db.Metadata;
+import org.briarproject.api.db.Transaction;
+import org.briarproject.api.sync.ClientId;
+import org.briarproject.api.sync.Group;
+import org.briarproject.api.sync.GroupId;
+import org.briarproject.api.sync.Message;
+import org.briarproject.api.sync.MessageId;
+import org.briarproject.api.sync.MessageValidator;
+import org.briarproject.api.sync.ValidationManager;
+import org.briarproject.api.sync.ValidationManager.IncomingMessageHook;
+import org.briarproject.util.ByteUtils;
+
+import java.util.Iterator;
+import java.util.Map.Entry;
+import java.util.TreeMap;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import static org.briarproject.api.clients.QueueMessage.QUEUE_MESSAGE_HEADER_LENGTH;
+import static org.briarproject.api.sync.SyncConstants.MESSAGE_HEADER_LENGTH;
+
+class MessageQueueManagerImpl implements MessageQueueManager {
+
+	private static final String OUTGOING_POSITION_KEY = "nextOut";
+	private static final String INCOMING_POSITION_KEY = "nextIn";
+	private static final String PENDING_MESSAGES_KEY = "pending";
+
+	private static final Logger LOG =
+			Logger.getLogger(MessageQueueManagerImpl.class.getName());
+
+	private final DatabaseComponent db;
+	private final ClientHelper clientHelper;
+	private final QueueMessageFactory queueMessageFactory;
+	private final ValidationManager validationManager;
+
+	@Inject
+	MessageQueueManagerImpl(DatabaseComponent db, ClientHelper clientHelper,
+			QueueMessageFactory queueMessageFactory,
+			ValidationManager validationManager) {
+		this.db = db;
+		this.clientHelper = clientHelper;
+		this.queueMessageFactory = queueMessageFactory;
+		this.validationManager = validationManager;
+	}
+
+	@Override
+	public QueueMessage sendMessage(Transaction txn, Group queue,
+			long timestamp, byte[] body, Metadata meta) throws DbException {
+		QueueState queueState = loadQueueState(txn, queue.getId());
+		long queuePosition = queueState.outgoingPosition;
+		queueState.outgoingPosition++;
+		saveQueueState(txn, queue.getId(), queueState);
+		QueueMessage q = queueMessageFactory.createMessage(queue.getId(),
+				timestamp, queuePosition, body);
+		db.addLocalMessage(txn, q, queue.getClientId(), meta, true);
+		return q;
+	}
+
+	@Override
+	public void registerMessageValidator(ClientId c, QueueMessageValidator v) {
+		validationManager.registerMessageValidator(c,
+				new DelegatingMessageValidator(v));
+	}
+
+	@Override
+	public void registerIncomingMessageHook(ClientId c,
+			IncomingQueueMessageHook hook) {
+		validationManager.registerIncomingMessageHook(c,
+				new DelegatingIncomingMessageHook(hook));
+	}
+
+	private QueueState loadQueueState(Transaction txn, GroupId g)
+			throws DbException {
+		try {
+			TreeMap<Long, MessageId> pending = new TreeMap<Long, MessageId>();
+			Metadata groupMeta = db.getGroupMetadata(txn, g);
+			byte[] raw = groupMeta.get(QUEUE_STATE_KEY);
+			if (raw == null) return new QueueState(0, 0, pending);
+			BdfDictionary d = clientHelper.toDictionary(raw, 0, raw.length);
+			long outgoingPosition = d.getLong(OUTGOING_POSITION_KEY);
+			long incomingPosition = d.getLong(INCOMING_POSITION_KEY);
+			BdfList pendingList = d.getList(PENDING_MESSAGES_KEY);
+			for (int i = 0; i < pendingList.size(); i++) {
+				BdfList item = pendingList.getList(i);
+				if (item.size() != 2) throw new FormatException();
+				pending.put(item.getLong(0), new MessageId(item.getRaw(1)));
+			}
+			return new QueueState(outgoingPosition, incomingPosition, pending);
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+	}
+
+	private void saveQueueState(Transaction txn, GroupId g,
+			QueueState queueState) throws DbException {
+		try {
+			BdfDictionary d = new BdfDictionary();
+			d.put(OUTGOING_POSITION_KEY, queueState.outgoingPosition);
+			d.put(INCOMING_POSITION_KEY, queueState.incomingPosition);
+			BdfList pendingList = new BdfList();
+			for (Entry<Long, MessageId> e : queueState.pending.entrySet())
+				pendingList.add(BdfList.of(e.getKey(), e.getValue()));
+			d.put(PENDING_MESSAGES_KEY, pendingList);
+			Metadata groupMeta = new Metadata();
+			groupMeta.put(QUEUE_STATE_KEY, clientHelper.toByteArray(d));
+			db.mergeGroupMetadata(txn, g, groupMeta);
+		} catch (FormatException e) {
+			throw new RuntimeException(e);
+		}
+	}
+
+	private static class QueueState {
+
+		private long outgoingPosition, incomingPosition;
+		private final TreeMap<Long, MessageId> pending;
+
+		QueueState(long outgoingPosition, long incomingPosition,
+				TreeMap<Long, MessageId> pending) {
+			this.outgoingPosition = outgoingPosition;
+			this.incomingPosition = incomingPosition;
+			this.pending = pending;
+		}
+
+		MessageId popIncomingMessageId() {
+			Iterator<Entry<Long, MessageId>> it = pending.entrySet().iterator();
+			if (!it.hasNext()) return null;
+			Entry<Long, MessageId> e = it.next();
+			if (!e.getKey().equals(incomingPosition)) return null;
+			it.remove();
+			incomingPosition++;
+			return e.getValue();
+		}
+	}
+
+	private static class DelegatingMessageValidator
+			implements MessageValidator {
+
+		private final QueueMessageValidator delegate;
+
+		DelegatingMessageValidator(QueueMessageValidator delegate) {
+			this.delegate = delegate;
+		}
+
+		@Override
+		public Metadata validateMessage(Message m, Group g) {
+			byte[] raw = m.getRaw();
+			if (raw.length < QUEUE_MESSAGE_HEADER_LENGTH) return null;
+			long queuePosition = ByteUtils.readUint64(raw,
+					MESSAGE_HEADER_LENGTH);
+			if (queuePosition < 0) return null;
+			QueueMessage q = new QueueMessage(m.getId(), m.getGroupId(),
+					m.getTimestamp(), queuePosition, raw);
+			return delegate.validateMessage(q, g);
+		}
+	}
+
+	private class DelegatingIncomingMessageHook implements IncomingMessageHook {
+
+		private final IncomingQueueMessageHook delegate;
+
+		DelegatingIncomingMessageHook(IncomingQueueMessageHook delegate) {
+			this.delegate = delegate;
+		}
+
+		@Override
+		public void incomingMessage(Transaction txn, Message m, Metadata meta)
+				throws DbException {
+			long queuePosition = ByteUtils.readUint64(m.getRaw(),
+					MESSAGE_HEADER_LENGTH);
+			QueueState queueState = loadQueueState(txn, m.getGroupId());
+			if (queuePosition < queueState.incomingPosition) {
+				// A message with this queue position has already been seen
+				LOG.warning("Deleting message with duplicate position");
+				db.deleteMessage(txn, m.getId());
+				db.deleteMessageMetadata(txn, m.getId());
+			} else if (queuePosition > queueState.incomingPosition) {
+				// The message is out of order, add it to the pending list
+				queueState.pending.put(queuePosition, m.getId());
+				saveQueueState(txn, m.getGroupId(), queueState);
+			} else {
+				// The message is in order, pass it to the delegate
+				QueueMessage q = new QueueMessage(m.getId(), m.getGroupId(),
+						m.getTimestamp(), queuePosition, m.getRaw());
+				delegate.incomingMessage(txn, q, meta);
+				queueState.incomingPosition++;
+				// Pass any consecutive messages to the delegate
+				MessageId id;
+				while ((id = queueState.popIncomingMessageId()) != null) {
+					byte[] raw = db.getRawMessage(txn, id);
+					meta = db.getMessageMetadata(txn, id);
+					q = queueMessageFactory.createMessage(id, raw);
+					delegate.incomingMessage(txn, q, meta);
+				}
+				saveQueueState(txn, m.getGroupId(), queueState);
+			}
+		}
+	}
+}

briar-core/src/org/briarproject/clients/PrivateGroupFactoryImpl.java

@@ -3,28 +3,26 @@ package org.briarproject.clients;
 import com.google.inject.Inject;
 
 import org.briarproject.api.Bytes;
+import org.briarproject.api.FormatException;
+import org.briarproject.api.clients.ClientHelper;
 import org.briarproject.api.clients.PrivateGroupFactory;
 import org.briarproject.api.contact.Contact;
-import org.briarproject.api.data.BdfWriter;
+import org.briarproject.api.data.BdfList;
-import org.briarproject.api.data.BdfWriterFactory;
 import org.briarproject.api.identity.AuthorId;
 import org.briarproject.api.sync.ClientId;
 import org.briarproject.api.sync.Group;
 import org.briarproject.api.sync.GroupFactory;
 
-import java.io.ByteArrayOutputStream;
-import java.io.IOException;
-
 class PrivateGroupFactoryImpl implements PrivateGroupFactory {
 
 	private final GroupFactory groupFactory;
-	private final BdfWriterFactory bdfWriterFactory;
+	private final ClientHelper clientHelper;
 
 	@Inject
 	PrivateGroupFactoryImpl(GroupFactory groupFactory,
-			BdfWriterFactory bdfWriterFactory) {
+			ClientHelper clientHelper) {
 		this.groupFactory = groupFactory;
-		this.bdfWriterFactory = bdfWriterFactory;
+		this.clientHelper = clientHelper;
 	}
 
 	@Override
@@ -36,22 +34,12 @@ class PrivateGroupFactoryImpl implements PrivateGroupFactory {
 	}
 
 	private byte[] createGroupDescriptor(AuthorId local, AuthorId remote) {
-		ByteArrayOutputStream out = new ByteArrayOutputStream();
-		BdfWriter w = bdfWriterFactory.createWriter(out);
 		try {
-			w.writeListStart();
+			if (Bytes.COMPARATOR.compare(local, remote) < 0)
-			if (Bytes.COMPARATOR.compare(local, remote) < 0) {
+				return clientHelper.toByteArray(BdfList.of(local, remote));
-				w.writeRaw(local.getBytes());
+			else return clientHelper.toByteArray(BdfList.of(remote, local));
-				w.writeRaw(remote.getBytes());
+		} catch (FormatException e) {
-			} else {
-				w.writeRaw(remote.getBytes());
-				w.writeRaw(local.getBytes());
-			}
-			w.writeListEnd();
-		} catch (IOException e) {
-			// Shouldn't happen with ByteArrayOutputStream
 			throw new RuntimeException(e);
 		}
-		return out.toByteArray();
 	}
 }

briar-core/src/org/briarproject/clients/QueueMessageFactoryImpl.java

@@ -0,0 +1,55 @@
+package org.briarproject.clients;
+
+import org.briarproject.api.UniqueId;
+import org.briarproject.api.clients.QueueMessage;
+import org.briarproject.api.clients.QueueMessageFactory;
+import org.briarproject.api.crypto.CryptoComponent;
+import org.briarproject.api.sync.GroupId;
+import org.briarproject.api.sync.MessageId;
+import org.briarproject.util.ByteUtils;
+
+import javax.inject.Inject;
+
+import static org.briarproject.api.clients.QueueMessage.MAX_QUEUE_MESSAGE_BODY_LENGTH;
+import static org.briarproject.api.clients.QueueMessage.QUEUE_MESSAGE_HEADER_LENGTH;
+import static org.briarproject.api.sync.SyncConstants.MAX_MESSAGE_LENGTH;
+import static org.briarproject.api.sync.SyncConstants.MESSAGE_HEADER_LENGTH;
+
+class QueueMessageFactoryImpl implements QueueMessageFactory {
+
+	private final CryptoComponent crypto;
+
+	@Inject
+	QueueMessageFactoryImpl(CryptoComponent crypto) {
+		this.crypto = crypto;
+	}
+
+	@Override
+	public QueueMessage createMessage(GroupId groupId, long timestamp,
+			long queuePosition, byte[] body) {
+		if (body.length > MAX_QUEUE_MESSAGE_BODY_LENGTH)
+			throw new IllegalArgumentException();
+		byte[] raw = new byte[QUEUE_MESSAGE_HEADER_LENGTH + body.length];
+		System.arraycopy(groupId.getBytes(), 0, raw, 0, UniqueId.LENGTH);
+		ByteUtils.writeUint64(timestamp, raw, UniqueId.LENGTH);
+		ByteUtils.writeUint64(queuePosition, raw, MESSAGE_HEADER_LENGTH);
+		System.arraycopy(body, 0, raw, QUEUE_MESSAGE_HEADER_LENGTH,
+				body.length);
+		MessageId id = new MessageId(crypto.hash(MessageId.LABEL, raw));
+		return new QueueMessage(id, groupId, timestamp, queuePosition, raw);
+	}
+
+	@Override
+	public QueueMessage createMessage(MessageId id, byte[] raw) {
+		if (raw.length < QUEUE_MESSAGE_HEADER_LENGTH)
+			throw new IllegalArgumentException();
+		if (raw.length > MAX_MESSAGE_LENGTH)
+			throw new IllegalArgumentException();
+		byte[] groupId = new byte[UniqueId.LENGTH];
+		System.arraycopy(raw, 0, groupId, 0, UniqueId.LENGTH);
+		long timestamp = ByteUtils.readUint64(raw, UniqueId.LENGTH);
+		long queuePosition = ByteUtils.readUint64(raw, MESSAGE_HEADER_LENGTH);
+		return new QueueMessage(id, new GroupId(groupId), timestamp,
+				queuePosition, raw);
+	}
+}

briar-core/src/org/briarproject/forum/ForumListValidator.java

@@ -20,7 +20,7 @@ class ForumListValidator extends BdfMessageValidator {
 	}
 
 	@Override
-	public BdfDictionary validateMessage(BdfList message, Group g,
+	protected BdfDictionary validateMessage(BdfList message, Group g,
 			long timestamp) throws FormatException {
 		// Version, forum list
 		checkSize(message, 2);