Retransmission with exponential backoff (untested).

briar-core/src/net/sf/briar/db/Database.java

@@ -418,6 +418,15 @@ interface Database<T> {
 	SubscriptionUpdate getSubscriptionUpdate(T txn, ContactId c,
 			long maxLatency) throws DbException;
 
+	/**
+	 * Returns the transmission count of the given message with respect to the
+	 * given contact.
+	 * <p>
+	 * Locking: contact read, message read.
+	 */
+	int getTransmissionCount(T txn, ContactId c, MessageId m)
+			throws DbException;
+
 	/**
 	 * Returns a collection of transport acks for the given contact, or null if
 	 * no acks are due.
@@ -567,15 +576,6 @@ interface Database<T> {
 	void setConnectionWindow(T txn, ContactId c, TransportId t, long period,
 			long centre, byte[] bitmap) throws DbException;
 
-	/**
-	 * Updates the expiry times of the given messages with respect to the given
-	 * contact, using the latency of the transport over which they were sent.
-	 * <p>
-	 * Locking: contact read, message write.
-	 */
-	void setMessageExpiry(T txn, ContactId c, Collection<MessageId> sent,
-			long maxLatency) throws DbException;
-
 	/**
 	 * Sets the user's rating for the given author.
 	 * <p>
@@ -674,4 +674,14 @@ interface Database<T> {
 	 */
 	void setTransportUpdateAcked(T txn, ContactId c, TransportId t,
 			long version) throws DbException;
+
+	/**
+	 * Updates the expiry times of the given messages with respect to the given
+	 * contact, using the given transmission counts and the latency of the
+	 * transport over which they were sent.
+	 * <p>
+	 * Locking: contact read, message write.
+	 */
+	void updateExpiryTimes(T txn, ContactId c, Map<MessageId, Integer> sent,
+			long maxLatency) throws DbException;
 }

briar-core/src/net/sf/briar/db/DatabaseComponentImpl.java

@@ -13,6 +13,7 @@ import java.util.ArrayList;
 import java.util.BitSet;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
@@ -491,6 +492,7 @@ DatabaseCleaner.Callback {
 	public Collection<byte[]> generateBatch(ContactId c, int maxLength,
 			long maxLatency) throws DbException {
 		Collection<MessageId> ids;
+		Map<MessageId, Integer> sent = new HashMap<MessageId, Integer>();
 		List<byte[]> messages = new ArrayList<byte[]>();
 		// Get some sendable messages from the database
 		contactLock.readLock().lock();
@@ -504,8 +506,10 @@ DatabaseCleaner.Callback {
 						if(!db.containsContact(txn, c))
 							throw new NoSuchContactException();
 						ids = db.getSendableMessages(txn, c, maxLength);
-						for(MessageId m : ids)
+						for(MessageId m : ids) {
 							messages.add(db.getRawMessage(txn, m));
+							sent.put(m, db.getTransmissionCount(txn, c, m));
+						}
 						db.commitTransaction(txn);
 					} catch(DbException e) {
 						db.abortTransaction(txn);
@@ -523,7 +527,7 @@ DatabaseCleaner.Callback {
 			try {
 				T txn = db.startTransaction();
 				try {
-					db.setMessageExpiry(txn, c, ids, maxLatency);
+					db.updateExpiryTimes(txn, c, sent, maxLatency);
 					db.commitTransaction(txn);
 				} catch(DbException e) {
 					db.abortTransaction(txn);
@@ -541,7 +545,7 @@ DatabaseCleaner.Callback {
 	public Collection<byte[]> generateBatch(ContactId c, int maxLength,
 			long maxLatency, Collection<MessageId> requested)
 					throws DbException {
-		Collection<MessageId> ids = new ArrayList<MessageId>();
+		Map<MessageId, Integer> sent = new HashMap<MessageId, Integer>();
 		List<byte[]> messages = new ArrayList<byte[]>();
 		// Get some sendable messages from the database
 		contactLock.readLock().lock();
@@ -561,7 +565,7 @@ DatabaseCleaner.Callback {
 							if(raw != null) {
 								if(raw.length > maxLength) break;
 								messages.add(raw);
-								ids.add(m);
+								sent.put(m, db.getTransmissionCount(txn, c, m));
 								maxLength -= raw.length;
 							}
 							it.remove();
@@ -583,7 +587,7 @@ DatabaseCleaner.Callback {
 			try {
 				T txn = db.startTransaction();
 				try {
-					db.setMessageExpiry(txn, c, ids, maxLatency);
+					db.updateExpiryTimes(txn, c, sent, maxLatency);
 					db.commitTransaction(txn);
 				} catch(DbException e) {
 					db.abortTransaction(txn);

briar-core/src/net/sf/briar/db/JdbcDatabase.java

@@ -99,6 +99,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " remoteVersion BIGINT UNSIGNED NOT NULL,"
 					+ " remoteAcked BOOLEAN NOT NULL,"
 					+ " expiry BIGINT UNSIGNED NOT NULL,"
+					+ " txCount INT UNSIGNED NOT NULL,"
 					+ " PRIMARY KEY (contactId),"
 					+ " FOREIGN KEY (contactid)"
 					+ " REFERENCES contacts (contactId)"
@@ -158,6 +159,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " contactId INT UNSIGNED NOT NULL,"
 					+ " seen BOOLEAN NOT NULL,"
 					+ " expiry BIGINT UNSIGNED NOT NULL,"
+					+ " txCount INT UNSIGNED NOT NULL,"
 					+ " PRIMARY KEY (messageId, contactId),"
 					+ " FOREIGN KEY (messageId)"
 					+ " REFERENCES messages (messageId)"
@@ -189,6 +191,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " remoteVersion BIGINT UNSIGNED NOT NULL,"
 					+ " remoteAcked BOOLEAN NOT NULL,"
 					+ " expiry BIGINT UNSIGNED NOT NULL,"
+					+ " txCount INT UNSIGNED NOT NULL,"
 					+ " PRIMARY KEY (contactId),"
 					+ " FOREIGN KEY (contactId)"
 					+ " REFERENCES contacts (contactId)"
@@ -228,6 +231,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 					+ " localVersion BIGINT UNSIGNED NOT NULL,"
 					+ " localAcked BIGINT UNSIGNED NOT NULL,"
 					+ " expiry BIGINT UNSIGNED NOT NULL,"
+					+ " txCount INT UNSIGNED NOT NULL,"
 					+ " PRIMARY KEY (contactId, transportId),"
 					+ " FOREIGN KEY (contactId)"
 					+ " REFERENCES contacts (contactId)"
@@ -508,10 +512,11 @@ abstract class JdbcDatabase implements Database<Connection> {
 			rs.close();
 			ps.close();
 			// Create a retention version row
-			sql = "INSERT INTO retentionVersions"
+			sql = "INSERT INTO retentionVersions (contactId, retention,"
-					+ " (contactId, retention, localVersion, localAcked,"
+					+ " localVersion, localAcked, remoteVersion, remoteAcked,"
-					+ " remoteVersion, remoteAcked, expiry)"
+					+ " expiry, txCount)"
-					+ " VALUES (?, ZERO(), ?, ZERO(), ZERO(), TRUE, ZERO())";
+					+ " VALUES (?, ZERO(), ?, ZERO(), ZERO(), TRUE, ZERO(),"
+					+ " ZERO())";
 			ps = txn.prepareStatement(sql);
 			ps.setInt(1, c.getInt());
 			ps.setInt(2, 1);
@@ -520,8 +525,9 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.close();
 			// Create a group version row
 			sql = "INSERT INTO groupVersions (contactId, localVersion,"
-					+ " localAcked, remoteVersion, remoteAcked, expiry)"
+					+ " localAcked, remoteVersion, remoteAcked, expiry,"
-					+ " VALUES (?, ?, ZERO(), ZERO(), TRUE, ZERO())";
+					+ " txCount)"
+					+ " VALUES (?, ?, ZERO(), ZERO(), TRUE, ZERO(), ZERO())";
 			ps = txn.prepareStatement(sql);
 			ps.setInt(1, c.getInt());
 			ps.setInt(2, 1);
@@ -538,8 +544,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.close();
 			if(transports.isEmpty()) return c;
 			sql = "INSERT INTO transportVersions (contactId, transportId,"
-					+ " localVersion, localAcked, expiry)"
+					+ " localVersion, localAcked, expiry, txCount)"
-					+ " VALUES (?, ?, ?, ZERO(), ZERO())";
+					+ " VALUES (?, ?, ?, ZERO(), ZERO(), ZERO())";
 			ps = txn.prepareStatement(sql);
 			ps.setInt(1, c.getInt());
 			ps.setInt(3, 1);
@@ -687,8 +693,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		try {
 			String sql = "INSERT INTO statuses"
-					+ " (messageId, contactId, seen, expiry)"
+					+ " (messageId, contactId, seen, expiry, txCount)"
-					+ " VALUES (?, ?, ?, ZERO())";
+					+ " VALUES (?, ?, ?, ZERO(), ZERO())";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(1, m.getBytes());
 			ps.setInt(2, c.getInt());
@@ -790,8 +796,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.close();
 			if(contacts.isEmpty()) return;
 			sql = "INSERT INTO transportVersions (contactId, transportId,"
-					+ " localVersion, localAcked, expiry)"
+					+ " localVersion, localAcked, expiry, txCount)"
-					+ " VALUES (?, ?, ?, ZERO(), ZERO())";
+					+ " VALUES (?, ?, ?, ZERO(), ZERO(), ZERO())";
 			ps = txn.prepareStatement(sql);
 			ps.setBytes(2, t.getBytes());
 			ps.setInt(3, 1);
@@ -826,7 +832,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 			ps.close();
 			// Bump the subscription version
 			sql = "UPDATE groupVersions"
-					+ " SET localVersion = localVersion + ?, expiry = ZERO()"
+					+ " SET localVersion = localVersion + ?,"
+					+ " expiry = ZERO(), txCount = ZERO()"
 					+ " WHERE contactId = ?";
 			ps = txn.prepareStatement(sql);
 			ps.setInt(1, 1);
@@ -1541,7 +1548,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT timestamp, localVersion"
+			String sql = "SELECT timestamp, localVersion, txCount"
 					+ " FROM messages AS m"
 					+ " JOIN retentionVersions AS rv"
 					+ " WHERE rv.contactId = ?"
@@ -1561,13 +1568,17 @@ abstract class JdbcDatabase implements Database<Connection> {
 			long retention = rs.getLong(1);
 			retention -= retention % RETENTION_MODULUS;
 			long version = rs.getLong(2);
+			int txCount = rs.getInt(3);
 			if(rs.next()) throw new DbStateException();
 			rs.close();
 			ps.close();
-			sql = "UPDATE retentionVersions SET expiry = ? WHERE contactId = ?";
+			sql = "UPDATE retentionVersions"
+					+ " SET expiry = ?, txCount = txCount + ?"
+					+ " WHERE contactId = ?";
 			ps = txn.prepareStatement(sql);
-			ps.setLong(1, calculateExpiry(now, maxLatency));
+			ps.setLong(1, calculateExpiry(now, maxLatency, txCount));
-			ps.setInt(2, c.getInt());
+			ps.setInt(2, 1);
+			ps.setInt(3, c.getInt());
 			int affected = ps.executeUpdate();
 			if(affected != 1) throw new DbStateException();
 			ps.close();
@@ -1817,7 +1828,7 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT g.groupId, name, key, localVersion"
+			String sql = "SELECT g.groupId, name, key, localVersion, txCount"
 					+ " FROM groups AS g"
 					+ " JOIN groupVisibilities AS vis"
 					+ " ON g.groupId = vis.groupId"
@@ -1832,20 +1843,25 @@ abstract class JdbcDatabase implements Database<Connection> {
 			rs = ps.executeQuery();
 			List<Group> subs = new ArrayList<Group>();
 			long version = 0;
+			int txCount = 0;
 			while(rs.next()) {
 				byte[] id = rs.getBytes(1);
 				String name = rs.getString(2);
 				byte[] key = rs.getBytes(3);
-				version = rs.getLong(4);
 				subs.add(new Group(new GroupId(id), name, key));
+				version = rs.getLong(4);
+				txCount = rs.getInt(5);
 			}
 			rs.close();
 			ps.close();
 			if(subs.isEmpty()) return null;
-			sql = "UPDATE groupVersions SET expiry = ? WHERE contactId = ?";
+			sql = "UPDATE groupVersions"
+					+ " SET expiry = ?, txCount = txCount + ?"
+					+ " WHERE contactId = ?";
 			ps = txn.prepareStatement(sql);
-			ps.setLong(1, calculateExpiry(now, maxLatency));
+			ps.setLong(1, calculateExpiry(now, maxLatency, txCount));
-			ps.setInt(2, c.getInt());
+			ps.setInt(2, 1);
+			ps.setInt(3, c.getInt());
 			int affected = ps.executeUpdate();
 			if(affected != 1) throw new DbStateException();
 			ps.close();
@@ -1858,6 +1874,30 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
+	public int getTransmissionCount(Connection txn, ContactId c, MessageId m)
+			throws DbException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT txCount FROM statuses"
+					+ " WHERE messageId = ? AND contactId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setBytes(1, m.getBytes());
+			ps.setInt(2, c.getInt());
+			rs = ps.executeQuery();
+			if(!rs.next()) throw new DbStateException();
+			int txCount = rs.getInt(1);
+			if(rs.next()) throw new DbStateException();
+			rs.close();
+			ps.close();
+			return txCount;
+		} catch(SQLException e) {
+			tryToClose(ps);
+			tryToClose(rs);
+			throw new DbException(e);
+		}
+	}
+
 	public Collection<TransportAck> getTransportAcks(Connection txn,
 			ContactId c) throws DbException {
 		PreparedStatement ps = null;
@@ -1906,7 +1946,8 @@ abstract class JdbcDatabase implements Database<Connection> {
 		PreparedStatement ps = null;
 		ResultSet rs = null;
 		try {
-			String sql = "SELECT tp.transportId, key, value, localVersion"
+			String sql = "SELECT tp.transportId, key, value, localVersion,"
+					+ " txCount"
 					+ " FROM transportProperties AS tp"
 					+ " JOIN transportVersions AS tv"
 					+ " ON tp.transportId = tv.transportId"
@@ -1920,32 +1961,39 @@ abstract class JdbcDatabase implements Database<Connection> {
 			List<TransportUpdate> updates = new ArrayList<TransportUpdate>();
 			TransportId lastId = null;
 			TransportProperties p = null;
+			List<Integer> txCounts = new ArrayList<Integer>();
 			while(rs.next()) {
 				TransportId id = new TransportId(rs.getBytes(1));
 				String key = rs.getString(2), value = rs.getString(3);
 				long version = rs.getLong(4);
+				int txCount = rs.getInt(5);
 				if(!id.equals(lastId)) {
 					p = new TransportProperties();
 					updates.add(new TransportUpdate(id, p, version));
+					txCounts.add(txCount);
 				}
 				p.put(key, value);
 			}
 			rs.close();
 			ps.close();
 			if(updates.isEmpty()) return null;
-			sql = "UPDATE transportVersions SET expiry = ?"
+			sql = "UPDATE transportVersions"
+					+ " SET expiry = ?, txCount = txCount + ?"
 					+ " WHERE contactId = ? AND transportId = ?";
 			ps = txn.prepareStatement(sql);
-			ps.setLong(1, calculateExpiry(now, maxLatency));
+			ps.setInt(2, 1);
-			ps.setInt(2, c.getInt());
+			ps.setInt(3, c.getInt());
+			int i = 0;
 			for(TransportUpdate u : updates) {
+				int txCount = txCounts.get(i++);
+				ps.setLong(1, calculateExpiry(now, maxLatency, txCount));
 				ps.setBytes(3, u.getId().getBytes());
 				ps.addBatch();
 			}
 			int [] batchAffected = ps.executeBatch();
 			if(batchAffected.length != updates.size())
 				throw new DbStateException();
-			for(int i = 0; i < batchAffected.length; i++) {
+			for(i = 0; i < batchAffected.length; i++) {
 				if(batchAffected[i] != 1) throw new DbStateException();
 			}
 			ps.close();
@@ -2405,41 +2453,6 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
-	public void setMessageExpiry(Connection txn, ContactId c,
-			Collection<MessageId> sent, long maxLatency) throws DbException {
-		long now = clock.currentTimeMillis();
-		PreparedStatement ps = null;
-		try {
-			String sql = "UPDATE statuses SET expiry = ?"
-					+ " WHERE messageId = ? AND contactId = ?";
-			ps = txn.prepareStatement(sql);
-			ps.setLong(1, calculateExpiry(now, maxLatency));
-			ps.setInt(3, c.getInt());
-			for(MessageId m : sent) {
-				ps.setBytes(2, m.getBytes());
-				ps.addBatch();
-			}
-			int[] batchAffected = ps.executeBatch();
-			if(batchAffected.length != sent.size())
-				throw new DbStateException();
-			for(int i = 0; i < batchAffected.length; i++) {
-				if(batchAffected[i] > 1) throw new DbStateException();
-			}
-			ps.close();
-		} catch(SQLException e) {
-			tryToClose(ps);
-			throw new DbException(e);
-		}
-	}
-
-	private long calculateExpiry(long now, long maxLatency) {
-		long roundTrip = maxLatency * 2;
-		if(roundTrip < 0) return Long.MAX_VALUE; // Overflow;
-		long expiry = now + roundTrip;
-		if(expiry < 0) return Long.MAX_VALUE; // Overflow
-		return expiry;
-	}
-
 	public Rating setRating(Connection txn, AuthorId a, Rating r)
 			throws DbException {
 		PreparedStatement ps = null;
@@ -2835,4 +2848,46 @@ abstract class JdbcDatabase implements Database<Connection> {
 			throw new DbException(e);
 		}
 	}
+
+	public void updateExpiryTimes(Connection txn, ContactId c,
+			Map<MessageId, Integer> sent, long maxLatency) throws DbException {
+		long now = clock.currentTimeMillis();
+		PreparedStatement ps = null;
+		try {
+			String sql = "UPDATE statuses"
+					+ " SET expiry = ?, txCount = txCount + ?"
+					+ " WHERE messageId = ? AND contactId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setInt(2, 1);
+			ps.setInt(4, c.getInt());
+			for(Entry<MessageId, Integer> e : sent.entrySet()) {
+				ps.setLong(1, calculateExpiry(now, maxLatency, e.getValue()));
+				ps.setBytes(3, e.getKey().getBytes());
+				ps.addBatch();
+			}
+			int[] batchAffected = ps.executeBatch();
+			if(batchAffected.length != sent.size())
+				throw new DbStateException();
+			for(int i = 0; i < batchAffected.length; i++) {
+				if(batchAffected[i] > 1) throw new DbStateException();
+			}
+			ps.close();
+		} catch(SQLException e) {
+			tryToClose(ps);
+			throw new DbException(e);
+		}
+	}
+
+	// FIXME: Refactor the exponential backoff logic into a separate class
+	private long calculateExpiry(long now, long maxLatency, int txCount) {
+		long roundTrip = maxLatency * 2;
+		if(roundTrip < 0) return Long.MAX_VALUE;
+		for(int i = 0; i < txCount; i++) {
+			roundTrip <<= 1;
+			if(roundTrip < 0) return Long.MAX_VALUE;
+		}
+		long expiry = now + roundTrip;
+		if(expiry < 0) return Long.MAX_VALUE;
+		return expiry;
+	}
 }

briar-tests/src/net/sf/briar/db/DatabaseComponentTest.java

@@ -8,6 +8,8 @@ import java.util.Arrays;
 import java.util.BitSet;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
 
 import net.sf.briar.BriarTestCase;
 import net.sf.briar.TestMessage;
@@ -677,6 +679,9 @@ public abstract class DatabaseComponentTest extends BriarTestCase {
 		final Collection<MessageId> sendable = Arrays.asList(messageId,
 				messageId1);
 		final Collection<byte[]> messages = Arrays.asList(raw, raw1);
+		final Map<MessageId, Integer> sent = new HashMap<MessageId, Integer>();
+		sent.put(messageId, 1);
+		sent.put(messageId1, 2);
 		Mockery context = new Mockery();
 		@SuppressWarnings("unchecked")
 		final Database<Object> database = context.mock(Database.class);
@@ -688,15 +693,19 @@ public abstract class DatabaseComponentTest extends BriarTestCase {
 			allowing(database).commitTransaction(txn);
 			allowing(database).containsContact(txn, contactId);
 			will(returnValue(true));
-			// Get the sendable messages
+			// Get the sendable messages and their transmission counts
 			oneOf(database).getSendableMessages(txn, contactId, size * 2);
 			will(returnValue(sendable));
 			oneOf(database).getRawMessage(txn, messageId);
 			will(returnValue(raw));
+			oneOf(database).getTransmissionCount(txn, contactId, messageId);
+			will(returnValue(1));
 			oneOf(database).getRawMessage(txn, messageId1);
 			will(returnValue(raw1));
+			oneOf(database).getTransmissionCount(txn, contactId, messageId1);
+			will(returnValue(2));
 			// Record the outstanding messages
-			oneOf(database).setMessageExpiry(txn, contactId, sendable,
+			oneOf(database).updateExpiryTimes(txn, contactId, sent,
 					Long.MAX_VALUE);
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, cleaner,
@@ -731,11 +740,13 @@ public abstract class DatabaseComponentTest extends BriarTestCase {
 			will(returnValue(null)); // Message is not sendable
 			oneOf(database).getRawMessageIfSendable(txn, contactId, messageId1);
 			will(returnValue(raw1)); // Message is sendable
+			oneOf(database).getTransmissionCount(txn, contactId, messageId1);
+			will(returnValue(2));
 			oneOf(database).getRawMessageIfSendable(txn, contactId, messageId2);
 			will(returnValue(null)); // Message is not sendable
 			// Mark the message as sent
-			oneOf(database).setMessageExpiry(txn, contactId,
+			oneOf(database).updateExpiryTimes(txn, contactId,
-					Arrays.asList(messageId1), Long.MAX_VALUE);
+					Collections.singletonMap(messageId1, 2), Long.MAX_VALUE);
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, cleaner,
 				shutdown);

briar-tests/src/net/sf/briar/db/H2DatabaseTest.java

@@ -523,8 +523,8 @@ public class H2DatabaseTest extends BriarTestCase {
 		assertTrue(it.hasNext());
 		assertEquals(messageId, it.next());
 		assertFalse(it.hasNext());
-		db.setMessageExpiry(txn, contactId, Arrays.asList(messageId),
+		db.updateExpiryTimes(txn, contactId,
-				Long.MAX_VALUE);
+				Collections.singletonMap(messageId, 0), Long.MAX_VALUE);
 
 		// The message should no longer be sendable
 		it = db.getSendableMessages(txn, contactId, ONE_MEGABYTE).iterator();