Add DB methods for getting and setting sync versions.

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

@@ -29,6 +29,7 @@ import org.briarproject.bramble.api.transport.TransportKeySet;
 import org.briarproject.bramble.api.transport.TransportKeys;
 
 import java.util.Collection;
+import java.util.List;
 import java.util.Map;
 
 import javax.annotation.Nullable;
@@ -427,6 +428,13 @@ public interface DatabaseComponent extends TransactionManager {
 	 */
 	Settings getSettings(Transaction txn, String namespace) throws DbException;
 
+	/**
+	 * Returns the versions of the sync protocol supported by the given contact.
+	 * <p/>
+	 * Read-only.
+	 */
+	List<Byte> getSyncVersions(Transaction txn, ContactId c) throws DbException;
+
 	/**
 	 * Returns all transport keys for the given transport.
 	 * <p/>
@@ -579,6 +587,12 @@ public interface DatabaseComponent extends TransactionManager {
 	void setReorderingWindow(Transaction txn, KeySetId k, TransportId t,
 			long timePeriod, long base, byte[] bitmap) throws DbException;
 
+	/**
+	 * Sets the versions of the sync protocol supported by the given contact.
+	 */
+	void setSyncVersions(Transaction txn, ContactId c, List<Byte> supported)
+			throws DbException;
+
 	/**
 	 * Marks the given transport keys as usable for outgoing streams.
 	 */

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

@@ -0,0 +1,34 @@
+package org.briarproject.bramble.api.sync.event;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.event.Event;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+
+import java.util.List;
+
+import javax.annotation.concurrent.Immutable;
+
+/**
+ * An event that is broadcast when the versions of the sync protocol supported
+ * by a contact are updated.
+ */
+@Immutable
+@NotNullByDefault
+public class SyncVersionsUpdatedEvent extends Event {
+
+	private final ContactId contactId;
+	private final List<Byte> supported;
+
+	public SyncVersionsUpdatedEvent(ContactId contactId, List<Byte> supported) {
+		this.contactId = contactId;
+		this.supported = supported;
+	}
+
+	public ContactId getContactId() {
+		return contactId;
+	}
+
+	public List<Byte> getSupportedVersions() {
+		return supported;
+	}
+}

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

@@ -33,6 +33,7 @@ import org.briarproject.bramble.api.transport.TransportKeySet;
 import org.briarproject.bramble.api.transport.TransportKeys;
 
 import java.util.Collection;
+import java.util.List;
 import java.util.Map;
 
 import javax.annotation.Nullable;
@@ -528,6 +529,13 @@ interface Database<T> {
 	 */
 	Settings getSettings(T txn, String namespace) throws DbException;
 
+	/**
+	 * Returns the versions of the sync protocol supported by the given contact.
+	 * <p/>
+	 * Read-only.
+	 */
+	List<Byte> getSyncVersions(T txn, ContactId c) throws DbException;
+
 	/**
 	 * Returns all transport keys for the given transport.
 	 * <p/>
@@ -700,6 +708,12 @@ interface Database<T> {
 	void setReorderingWindow(T txn, KeySetId k, TransportId t,
 			long timePeriod, long base, byte[] bitmap) throws DbException;
 
+	/**
+	 * Sets the versions of the sync protocol supported by the given contact.
+	 */
+	void setSyncVersions(T txn, ContactId c, List<Byte> supported)
+			throws DbException;
+
 	/**
 	 * Marks the given transport keys as usable for outgoing streams.
 	 */

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

@@ -65,6 +65,7 @@ import org.briarproject.bramble.api.sync.event.MessageToAckEvent;
 import org.briarproject.bramble.api.sync.event.MessageToRequestEvent;
 import org.briarproject.bramble.api.sync.event.MessagesAckedEvent;
 import org.briarproject.bramble.api.sync.event.MessagesSentEvent;
+import org.briarproject.bramble.api.sync.event.SyncVersionsUpdatedEvent;
 import org.briarproject.bramble.api.sync.validation.MessageState;
 import org.briarproject.bramble.api.transport.KeySetId;
 import org.briarproject.bramble.api.transport.TransportKeySet;
@@ -716,6 +717,15 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		return db.getSettings(txn, namespace);
 	}
 
+	@Override
+	public List<Byte> getSyncVersions(Transaction transaction, ContactId c)
+			throws DbException {
+		T txn = unbox(transaction);
+		if (!db.containsContact(txn, c))
+			throw new NoSuchContactException();
+		return db.getSyncVersions(txn, c);
+	}
+
 	@Override
 	public Collection<TransportKeySet> getTransportKeys(Transaction transaction,
 			TransportId t) throws DbException {
@@ -1046,6 +1056,17 @@ class DatabaseComponentImpl<T> implements DatabaseComponent {
 		db.setReorderingWindow(txn, k, t, timePeriod, base, bitmap);
 	}
 
+	@Override
+	public void setSyncVersions(Transaction transaction, ContactId c,
+			List<Byte> supported) throws DbException {
+		if (transaction.isReadOnly()) throw new IllegalArgumentException();
+		T txn = unbox(transaction);
+		if (!db.containsContact(txn, c))
+			throw new NoSuchContactException();
+		db.setSyncVersions(txn, c, supported);
+		transaction.attach(new SyncVersionsUpdatedEvent(c, supported));
+	}
+
 	@Override
 	public void setTransportKeysActive(Transaction transaction, TransportId t,
 			KeySetId k) throws DbException {

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

@@ -2330,6 +2330,32 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
+	@Override
+	public List<Byte> getSyncVersions(Connection txn, ContactId c)
+			throws DbException {
+		PreparedStatement ps = null;
+		ResultSet rs = null;
+		try {
+			String sql = "SELECT syncVersions FROM contacts"
+					+ " WHERE contactId = ?";
+			ps = txn.prepareStatement(sql);
+			ps.setInt(1, c.getInt());
+			rs = ps.executeQuery();
+			if (!rs.next()) throw new DbStateException();
+			byte[] bytes = rs.getBytes(1);
+			List<Byte> supported = new ArrayList<>(bytes.length);
+			for (byte b : bytes) supported.add(b);
+			if (rs.next()) throw new DbStateException();
+			rs.close();
+			ps.close();
+			return supported;
+		} catch (SQLException e) {
+			tryToClose(rs, LOG, WARNING);
+			tryToClose(ps, LOG, WARNING);
+			throw new DbException(e);
+		}
+	}
+
 	@Override
 	public Collection<TransportKeySet> getTransportKeys(Connection txn,
 			TransportId t) throws DbException {
@@ -3163,6 +3189,29 @@ abstract class JdbcDatabase implements Database<Connection> {
 		}
 	}
 
+	@Override
+	public void setSyncVersions(Connection txn, ContactId c,
+			List<Byte> supported) throws DbException {
+		PreparedStatement ps = null;
+		try {
+			String sql = "UPDATE contacts SET syncVersions = ?"
+					+ " WHERE contactId = ?";
+			ps = txn.prepareStatement(sql);
+			byte[] bytes = new byte[supported.size()];
+			for (int i = 0; i < bytes.length; i++) {
+				bytes[i] = supported.get(i);
+			}
+			ps.setBytes(1, bytes);
+			ps.setInt(2, c.getInt());
+			int affected = ps.executeUpdate();
+			if (affected < 0 || affected > 1) throw new DbStateException();
+			ps.close();
+		} catch (SQLException e) {
+			tryToClose(ps, LOG, WARNING);
+			throw new DbException(e);
+		}
+	}
+
 	@Override
 	public void setTransportKeysActive(Connection txn, TransportId t,
 			KeySetId k) throws DbException {

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

@@ -66,6 +66,7 @@ import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicReference;
 
 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 org.briarproject.bramble.api.sync.Group.Visibility.INVISIBLE;
@@ -294,11 +295,11 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			throws Exception {
 		context.checking(new Expectations() {{
 			// Check whether the contact is in the DB (which it's not)
-			exactly(16).of(database).startTransaction();
+			exactly(18).of(database).startTransaction();
 			will(returnValue(txn));
-			exactly(16).of(database).containsContact(txn, contactId);
+			exactly(18).of(database).containsContact(txn, contactId);
 			will(returnValue(false));
-			exactly(16).of(database).abortTransaction(txn);
+			exactly(18).of(database).abortTransaction(txn);
 		}});
 		DatabaseComponent db = createDatabaseComponent(database, eventBus,
 				eventExecutor, shutdownManager);
@@ -376,6 +377,14 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 			// Expected
 		}
 
+		try {
+			db.transaction(false, transaction ->
+					db.getSyncVersions(transaction, contactId));
+			fail();
+		} catch (NoSuchContactException expected) {
+			// Expected
+		}
+
 		try {
 			Ack a = new Ack(singletonList(messageId));
 			db.transaction(false, transaction ->
@@ -435,6 +444,14 @@ public class DatabaseComponentImplTest extends BrambleMockTestCase {
 		} catch (NoSuchContactException expected) {
 			// Expected
 		}
+
+		try {
+			db.transaction(false, transaction ->
+					db.setSyncVersions(transaction, contactId, emptyList()));
+			fail();
+		} catch (NoSuchContactException expected) {
+			// Expected
+		}
 	}
 
 	@Test

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

@@ -41,7 +41,6 @@ import org.junit.Test;
 import java.io.File;
 import java.sql.Connection;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
 import java.util.Map;
@@ -51,6 +50,7 @@ import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicLong;
 
+import static java.util.Arrays.asList;
 import static java.util.Collections.emptyList;
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonList;
@@ -407,10 +407,10 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 
 		// Both message IDs should be returned
 		Collection<MessageId> ids = db.getMessagesToAck(txn, contactId, 1234);
-		assertEquals(Arrays.asList(messageId, messageId1), ids);
+		assertEquals(asList(messageId, messageId1), ids);
 
 		// Remove both message IDs
-		db.lowerAckFlag(txn, contactId, Arrays.asList(messageId, messageId1));
+		db.lowerAckFlag(txn, contactId, asList(messageId, messageId1));
 
 		// Both message IDs should have been removed
 		assertEquals(emptyList(), db.getMessagesToAck(txn,
@@ -422,7 +422,7 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 
 		// Both message IDs should be returned
 		ids = db.getMessagesToAck(txn, contactId, 1234);
-		assertEquals(Arrays.asList(messageId, messageId1), ids);
+		assertEquals(asList(messageId, messageId1), ids);
 
 		db.commitTransaction(txn);
 		db.close();
@@ -2286,6 +2286,29 @@ public abstract class JdbcDatabaseTest extends BrambleTestCase {
 		db.close();
 	}
 
+	@Test
+	public void testSyncVersions() throws Exception {
+		Database<Connection> db = open(false);
+		Connection txn = db.startTransaction();
+
+		// Add a contact
+		db.addIdentity(txn, identity);
+		assertEquals(contactId,
+				db.addContact(txn, author, localAuthor.getId(), null, true));
+
+		// Only sync version 0 should be supported by default
+		List<Byte> defaultSupported = singletonList((byte) 0);
+		assertEquals(defaultSupported, db.getSyncVersions(txn, contactId));
+
+		// Set the supported versions and check that they're returned
+		List<Byte> supported = asList((byte) 0, (byte) 1);
+		db.setSyncVersions(txn, contactId, supported);
+		assertEquals(supported, db.getSyncVersions(txn, contactId));
+
+		db.commitTransaction(txn);
+		db.close();
+	}
+
 	private Database<Connection> open(boolean resume) throws Exception {
 		return open(resume, new TestMessageFactory(), new SystemClock());
 	}