Include mailbox API version in local and remote mailbox properties

This changes the format of the mailbox properties update message, so
the major version of the client is bumped.

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

@@ -26,6 +26,8 @@ import org.briarproject.bramble.api.identity.AuthorFactory;
 import org.briarproject.bramble.api.mailbox.MailboxAuthToken;
 import org.briarproject.bramble.api.mailbox.MailboxFolderId;
 import org.briarproject.bramble.api.mailbox.MailboxPropertiesUpdate;
+import org.briarproject.bramble.api.mailbox.MailboxPropertiesUpdateMailbox;
+import org.briarproject.bramble.api.mailbox.MailboxVersion;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.plugin.TransportId;
 import org.briarproject.bramble.api.properties.TransportProperties;
@@ -39,12 +41,13 @@ import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.security.GeneralSecurityException;
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 
-import javax.annotation.Nullable;
 import javax.annotation.concurrent.Immutable;
 import javax.inject.Inject;
 
@@ -412,11 +415,28 @@ class ClientHelperImpl implements ClientHelper {
 	}
 
 	@Override
-	@Nullable
 	public MailboxPropertiesUpdate parseAndValidateMailboxPropertiesUpdate(
+			BdfList clientSupports, BdfList serverSupports,
 			BdfDictionary properties) throws FormatException {
+		List<MailboxVersion> clientSupportsList =
+				getMailboxVersionList(clientSupports);
+		List<MailboxVersion> serverSupportsList =
+				getMailboxVersionList(serverSupports);
+
+		// We must always learn what Mailbox API version(s) the client supports
+		if (clientSupports.isEmpty()) {
+			throw new FormatException();
+		}
 		if (properties.isEmpty()) {
-			return null;
+			// No mailbox -- cannot claim to support any API versions!
+			if (!serverSupports.isEmpty()) {
+				throw new FormatException();
+			}
+			return new MailboxPropertiesUpdate(clientSupportsList);
+		}
+		// Mailbox must be accompanied by the Mailbox API version(s) it supports
+		if (serverSupports.isEmpty()) {
+			throw new FormatException();
 		}
 		// Accepting more props than we need, for forward compatibility
 		if (properties.size() < PROP_COUNT) {
@@ -435,9 +455,23 @@ class ClientHelperImpl implements ClientHelper {
 		checkLength(inboxId, UniqueId.LENGTH);
 		byte[] outboxId = properties.getRaw(PROP_KEY_OUTBOXID);
 		checkLength(outboxId, UniqueId.LENGTH);
-		return new MailboxPropertiesUpdate(onion,
-				new MailboxAuthToken(authToken), new MailboxFolderId(inboxId),
-				new MailboxFolderId(outboxId));
+		return new MailboxPropertiesUpdateMailbox(clientSupportsList,
+				serverSupportsList, onion, new MailboxAuthToken(authToken),
+				new MailboxFolderId(inboxId), new MailboxFolderId(outboxId));
+	}
+
+	private List<MailboxVersion> getMailboxVersionList(BdfList bdfList)
+			throws FormatException {
+		List<MailboxVersion> list = new ArrayList<>();
+		for (int i = 0; i < bdfList.size(); i++) {
+			BdfList element = bdfList.getList(i);
+			if (element.size() != 2) {
+				throw new FormatException();
+			}
+			list.add(new MailboxVersion(element.getLong(0).intValue(),
+					element.getLong(1).intValue()));
+		}
+		return list;
 	}
 
 	@Override

bramble-core/src/main/java/org/briarproject/bramble/mailbox/MailboxApi.java

@@ -7,6 +7,8 @@ import org.briarproject.bramble.api.mailbox.MailboxAuthToken;
 import org.briarproject.bramble.api.mailbox.MailboxFileId;
 import org.briarproject.bramble.api.mailbox.MailboxFolderId;
 import org.briarproject.bramble.api.mailbox.MailboxProperties;
+import org.briarproject.bramble.api.mailbox.MailboxPropertyManager;
+import org.briarproject.bramble.api.mailbox.MailboxVersion;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 
 import java.io.File;
@@ -17,9 +19,18 @@ import java.util.List;
 import javax.annotation.Nonnull;
 import javax.annotation.concurrent.Immutable;
 
+import static java.util.Collections.singletonList;
+
 @NotNullByDefault
 interface MailboxApi {
 
+	/**
+	 * Mailbox API versions that we support as a client. This is reported to our
+	 * contacts by {@link MailboxPropertyManager}.
+	 */
+	List<MailboxVersion> CLIENT_SUPPORTS = singletonList(
+			new MailboxVersion(1, 0));
+
 	/**
 	 * Sets up the mailbox with the setup token.
 	 *

bramble-core/src/main/java/org/briarproject/bramble/mailbox/MailboxPairingTaskImpl.java

@@ -127,7 +127,7 @@ class MailboxPairingTaskImpl implements MailboxPairingTask {
 			for (Contact c : db.getContacts(txn)) {
 				MailboxPropertiesUpdate remoteProps = mailboxPropertyManager
 						.getRemoteProperties(txn, c.getId());
-				if (remoteProps == null) {
+				if (remoteProps == null || !remoteProps.hasMailbox()) {
 					db.resetUnackedMessagesToSend(txn, c.getId());
 				}
 			}

bramble-core/src/main/java/org/briarproject/bramble/mailbox/MailboxPropertyManagerImpl.java

@@ -19,9 +19,11 @@ import org.briarproject.bramble.api.mailbox.MailboxAuthToken;
 import org.briarproject.bramble.api.mailbox.MailboxFolderId;
 import org.briarproject.bramble.api.mailbox.MailboxProperties;
 import org.briarproject.bramble.api.mailbox.MailboxPropertiesUpdate;
+import org.briarproject.bramble.api.mailbox.MailboxPropertiesUpdateMailbox;
 import org.briarproject.bramble.api.mailbox.MailboxPropertyManager;
 import org.briarproject.bramble.api.mailbox.MailboxSettingsManager;
 import org.briarproject.bramble.api.mailbox.MailboxSettingsManager.MailboxHook;
+import org.briarproject.bramble.api.mailbox.MailboxVersion;
 import org.briarproject.bramble.api.mailbox.RemoteMailboxPropertiesUpdateEvent;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.Group;
@@ -35,6 +37,7 @@ import org.briarproject.bramble.api.system.Clock;
 import org.briarproject.bramble.api.versioning.ClientVersioningManager;
 import org.briarproject.bramble.api.versioning.ClientVersioningManager.ClientVersioningHook;
 
+import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 
@@ -42,6 +45,7 @@ import javax.annotation.Nullable;
 import javax.inject.Inject;
 
 import static org.briarproject.bramble.api.sync.validation.IncomingMessageHook.DeliveryAction.ACCEPT_DO_NOT_SHARE;
+import static org.briarproject.bramble.mailbox.MailboxApi.CLIENT_SUPPORTS;
 
 @NotNullByDefault
 class MailboxPropertyManagerImpl implements MailboxPropertyManager,
@@ -100,11 +104,15 @@ class MailboxPropertyManagerImpl implements MailboxPropertyManager,
 		db.setGroupVisibility(txn, c.getId(), g.getId(), client);
 		// Attach the contact ID to the group
 		clientHelper.setContactId(txn, g.getId(), c.getId());
-		// If we are paired, create and send props to the newly added contact
 		MailboxProperties ownProps =
 				mailboxSettingsManager.getOwnMailboxProperties(txn);
 		if (ownProps != null) {
-			createAndSendProperties(txn, c, ownProps.getOnion());
+			// We are paired, create and send props to the newly added contact
+			createAndSendProperties(txn, c, ownProps.getServerSupports(),
+					ownProps.getOnion());
+		} else {
+			// Not paired, but we still want to get our clientSupports sent
+			sendEmptyProperties(txn, c);
 		}
 	}
 
@@ -114,10 +122,11 @@ class MailboxPropertyManagerImpl implements MailboxPropertyManager,
 	}
 
 	@Override
-	public void mailboxPaired(Transaction txn, String ownOnion)
+	public void mailboxPaired(Transaction txn, String ownOnion,
+			List<MailboxVersion> serverSupports)
 			throws DbException {
 		for (Contact c : db.getContacts(txn)) {
-			createAndSendProperties(txn, c, ownOnion);
+			createAndSendProperties(txn, c, serverSupports, ownOnion);
 		}
 	}
 
@@ -186,12 +195,15 @@ class MailboxPropertyManagerImpl implements MailboxPropertyManager,
 
 	/**
 	 * Creates and sends an update message to the given contact. The message
-	 * holds our own mailbox's onion, and generated unique properties. All of
-	 * which the contact needs to communicate with our Mailbox.
+	 * holds our own mailbox's onion, generated unique properties, and lists of
+	 * supported Mailbox API version(s). All of which the contact needs to
+	 * communicate with our Mailbox.
 	 */
-	private void createAndSendProperties(Transaction txn,
-			Contact c, String ownOnion) throws DbException {
-		MailboxPropertiesUpdate p = new MailboxPropertiesUpdate(ownOnion,
+	private void createAndSendProperties(Transaction txn, Contact c,
+			List<MailboxVersion> serverSupports, String ownOnion)
+			throws DbException {
+		MailboxPropertiesUpdate p = new MailboxPropertiesUpdateMailbox(
+				CLIENT_SUPPORTS, serverSupports, ownOnion,
 				new MailboxAuthToken(crypto.generateUniqueId().getBytes()),
 				new MailboxFolderId(crypto.generateUniqueId().getBytes()),
 				new MailboxFolderId(crypto.generateUniqueId().getBytes()));
@@ -200,14 +212,17 @@ class MailboxPropertyManagerImpl implements MailboxPropertyManager,
 	}
 
 	/**
-	 * Sends an empty update message to the given contact. The empty update
-	 * indicates for the receiving contact that we no longer have a Mailbox that
-	 * they can use.
+	 * Sends an update message with empty properties to the given contact. The
+	 * empty update indicates for the receiving contact that we don't have any
+	 * Mailbox that they can use. It still includes the list of Mailbox API
+	 * version(s) that we support as a client.
 	 */
 	private void sendEmptyProperties(Transaction txn, Contact c)
 			throws DbException {
 		Group g = getContactGroup(c);
-		storeMessageReplaceLatest(txn, g.getId(), null);
+		MailboxPropertiesUpdate p =
+				new MailboxPropertiesUpdate(CLIENT_SUPPORTS);
+		storeMessageReplaceLatest(txn, g.getId(), p);
 	}
 
 	@Nullable
@@ -229,7 +244,7 @@ class MailboxPropertyManagerImpl implements MailboxPropertyManager,
 	}
 
 	private void storeMessageReplaceLatest(Transaction txn, GroupId g,
-			@Nullable MailboxPropertiesUpdate p) throws DbException {
+			MailboxPropertiesUpdate p) throws DbException {
 		try {
 			LatestUpdate latest = findLatest(txn, g, true);
 			long version = latest == null ? 1 : latest.version + 1;
@@ -266,23 +281,38 @@ class MailboxPropertyManagerImpl implements MailboxPropertyManager,
 		return null;
 	}
 
-	private BdfList encodeProperties(long version,
-			@Nullable MailboxPropertiesUpdate p) {
+	private BdfList encodeProperties(long version, MailboxPropertiesUpdate p) {
 		BdfDictionary dict = new BdfDictionary();
-		if (p != null) {
-			dict.put(PROP_KEY_ONION, p.getOnion());
-			dict.put(PROP_KEY_AUTHTOKEN, p.getAuthToken().getBytes());
-			dict.put(PROP_KEY_INBOXID, p.getInboxId().getBytes());
-			dict.put(PROP_KEY_OUTBOXID, p.getOutboxId().getBytes());
+		BdfList serverSupports = new BdfList();
+		if (p.hasMailbox()) {
+			MailboxPropertiesUpdateMailbox pm =
+					(MailboxPropertiesUpdateMailbox) p;
+			serverSupports = encodeSupportsList(pm.getServerSupports());
+			dict.put(PROP_KEY_ONION, pm.getOnion());
+			dict.put(PROP_KEY_AUTHTOKEN, pm.getAuthToken().getBytes());
+			dict.put(PROP_KEY_INBOXID, pm.getInboxId().getBytes());
+			dict.put(PROP_KEY_OUTBOXID, pm.getOutboxId().getBytes());
 		}
-		return BdfList.of(version, dict);
+		return BdfList.of(version, encodeSupportsList(p.getClientSupports()),
+				serverSupports, dict);
+	}
+
+	private BdfList encodeSupportsList(List<MailboxVersion> supportsList) {
+		BdfList supports = new BdfList();
+		for (MailboxVersion version : supportsList) {
+			supports.add(BdfList.of(version.getMajor(), version.getMinor()));
+		}
+		return supports;
 	}
 
-	@Nullable
 	private MailboxPropertiesUpdate parseProperties(BdfList body)
 			throws FormatException {
-		BdfDictionary dict = body.getDictionary(1);
-		return clientHelper.parseAndValidateMailboxPropertiesUpdate(dict);
+		BdfList clientSupports = body.getList(1);
+		BdfList serverSupports = body.getList(2);
+		BdfDictionary dict = body.getDictionary(3);
+		return clientHelper.parseAndValidateMailboxPropertiesUpdate(
+				clientSupports, serverSupports, dict
+		);
 	}
 
 	private Group getContactGroup(Contact c) {

bramble-core/src/main/java/org/briarproject/bramble/mailbox/MailboxPropertyValidator.java

@@ -31,14 +31,20 @@ class MailboxPropertyValidator extends BdfMessageValidator {
 	@Override
 	protected BdfMessageContext validateMessage(Message m, Group g,
 			BdfList body) throws InvalidMessageException, FormatException {
-		// Version, properties
-		checkSize(body, 2);
+		// Version, Properties, clientSupports, serverSupports
+		checkSize(body, 4);
 		// Version
 		long version = body.getLong(0);
 		if (version < 0) throw new FormatException();
+		// clientSupports
+		BdfList clientSupports = body.getList(1);
+		// serverSupports
+		BdfList serverSupports = body.getList(2);
 		// Properties
-		BdfDictionary dictionary = body.getDictionary(1);
-		clientHelper.parseAndValidateMailboxPropertiesUpdate(dictionary);
+		BdfDictionary dictionary = body.getDictionary(3);
+		clientHelper.parseAndValidateMailboxPropertiesUpdate(clientSupports,
+				serverSupports, dictionary
+		);
 		// Return the metadata
 		BdfDictionary meta = new BdfDictionary();
 		meta.put(MSG_KEY_VERSION, version);

bramble-core/src/main/java/org/briarproject/bramble/mailbox/MailboxSettingsManagerImpl.java

@@ -91,7 +91,7 @@ class MailboxSettingsManagerImpl implements MailboxSettingsManager {
 		s.putIntArray(SETTINGS_KEY_SERVER_SUPPORTS, ints);
 		settingsManager.mergeSettings(txn, s, SETTINGS_NAMESPACE);
 		for (MailboxHook hook : hooks) {
-			hook.mailboxPaired(txn, p.getOnion());
+			hook.mailboxPaired(txn, p.getOnion(), p.getServerSupports());
 		}
 	}