Merge branch '1627-delete-completed-privategroup-sessions' into 'master'

Delete conversation messages belonging to completed private group sessions

Closes #1627

See merge request briar/briar!1167

briar-android/src/main/res/values/strings.xml

@@ -139,7 +139,7 @@
 	<string name="dialog_title_delete_all_messages">Confirm Message Deletion</string>
 	<string name="dialog_message_delete_all_messages">Are you sure that you want to delete all messages?</string>
 	<string name="dialog_title_not_all_messages_deleted">Could not delete all messages</string>
-	<string name="dialog_message_not_all_messages_deleted">Messages related to introductions or invitations cannot be deleted at the moment.</string>
+	<string name="dialog_message_not_all_messages_deleted">Messages related to ongoing introductions or invitations cannot be deleted until they conclude.</string>
 	<string name="delete_contact">Delete contact</string>
 	<string name="dialog_title_delete_contact">Confirm Contact Deletion</string>
 	<string name="dialog_message_delete_contact">Are you sure that you want to remove this contact and all messages exchanged with this contact?</string>

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/CreatorState.java

@@ -38,6 +38,11 @@ enum CreatorState implements State {
 		return visibility;
 	}
 
+	@Override
+	public boolean isAwaitingResponse() {
+		return this == INVITED;
+	}
+
 	static CreatorState fromValue(int value) throws FormatException {
 		for (CreatorState s : values()) if (s.value == value) return s;
 		throw new FormatException();

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/GroupInvitationManagerImpl.java

@@ -40,6 +40,7 @@ import org.briarproject.briar.client.ConversationClientImpl;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
@@ -369,7 +370,8 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 	}
 
 	@Override
-	public Collection<ConversationMessageHeader> getMessageHeaders(Transaction txn,
+	public Collection<ConversationMessageHeader> getMessageHeaders(
+			Transaction txn,
 			ContactId c) throws DbException {
 		try {
 			Contact contact = db.getContact(txn, c);
@@ -633,8 +635,98 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 	@Override
 	public boolean deleteAllMessages(Transaction txn, ContactId c)
 			throws DbException {
-		// TODO actually delete messages (#1627 and #1629)
-		return getMessageIds(txn, c).size() == 0;
+		// get ID of the contact group
+		GroupId g = getContactGroup(db.getContact(txn, c)).getId();
+
+		// get metadata for all messages in the
+		// (these are sessions *and* protocol messages)
+		Map<MessageId, BdfDictionary> metadata;
+		try {
+			metadata = clientHelper.getMessageMetadataAsDictionary(txn, g);
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+
+		// get all sessions and their states
+		Map<GroupId, DeletableSession> sessions = new HashMap<>();
+		for (BdfDictionary d : metadata.values()) {
+			if (!sessionParser.isSession(d)) continue;
+			Session session;
+			try {
+				Role role = sessionParser.getRole(d);
+				if (role == CREATOR) {
+					session = sessionParser.parseCreatorSession(g, d);
+				} else if (role == INVITEE) {
+					session = sessionParser.parseInviteeSession(g, d);
+				} else if (role == PEER) {
+					session = sessionParser.parsePeerSession(g, d);
+				} else throw new AssertionError("unknown role");
+			} catch (FormatException e) {
+				throw new DbException(e);
+			}
+			sessions.put(session.getPrivateGroupId(),
+					new DeletableSession(session.getState()));
+		}
+
+		// assign protocol messages to their sessions
+		for (Entry<MessageId, BdfDictionary> entry : metadata.entrySet()) {
+			// skip all sessions, we are only interested in messages
+			BdfDictionary d = entry.getValue();
+			if (sessionParser.isSession(d)) continue;
+
+			// parse message metadata and skip messages not visible in UI
+			MessageMetadata m;
+			try {
+				m = messageParser.parseMetadata(d);
+			} catch (FormatException e) {
+				throw new DbException(e);
+			}
+			if (!m.isVisibleInConversation()) continue;
+
+			// add visible messages to session
+			DeletableSession session = sessions.get(m.getPrivateGroupId());
+			session.messages.add(entry.getKey());
+		}
+
+		// get a set of all messages which were not ACKed by the contact
+		Set<MessageId> notAcked = new HashSet<>();
+		for (MessageStatus status : db.getMessageStatus(txn, c, g)) {
+			if (!status.isSeen()) notAcked.add(status.getMessageId());
+		}
+		boolean allDeleted =
+				deleteCompletedSessions(txn, sessions.values(), notAcked);
+		recalculateGroupCount(txn, g);
+		return allDeleted;
+	}
+
+	private boolean deleteCompletedSessions(Transaction txn,
+			Collection<DeletableSession> sessions, Set<MessageId> notAcked)
+			throws DbException {
+		// find completed sessions to delete
+		boolean allDeleted = true;
+		for (DeletableSession session : sessions) {
+			if (session.state.isAwaitingResponse()) {
+				allDeleted = false;
+				continue;
+			}
+			// we can only delete sessions
+			// where delivery of all messages was confirmed (aka ACKed)
+			boolean allAcked = true;
+			for (MessageId m : session.messages) {
+				if (notAcked.contains(m)) {
+					allAcked = false;
+					allDeleted = false;
+					break;
+				}
+			}
+			if (allAcked) {
+				for (MessageId m : session.messages) {
+					db.deleteMessage(txn, m);
+					db.deleteMessageMetadata(txn, m);
+				}
+			}
+		}
+		return allDeleted;
 	}
 
 	private Set<MessageId> getMessageIds(Transaction txn, ContactId c)
@@ -650,6 +742,31 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 		}
 	}
 
+	private void recalculateGroupCount(Transaction txn, GroupId g)
+			throws DbException {
+		BdfDictionary query = messageParser.getMessagesVisibleInUiQuery();
+		Map<MessageId, BdfDictionary> results;
+		try {
+			results =
+					clientHelper.getMessageMetadataAsDictionary(txn, g, query);
+		} catch (FormatException e) {
+			throw new DbException(e);
+		}
+		int msgCount = 0;
+		int unreadCount = 0;
+		for (Entry<MessageId, BdfDictionary> entry : results.entrySet()) {
+			MessageMetadata meta;
+			try {
+				meta = messageParser.parseMetadata(entry.getValue());
+			} catch (FormatException e) {
+				throw new DbException(e);
+			}
+			msgCount++;
+			if (!meta.isRead()) unreadCount++;
+		}
+		messageTracker.resetGroupCount(txn, g, msgCount, unreadCount);
+	}
+
 	private static class StoredSession {
 
 		private final MessageId storageId;
@@ -660,4 +777,14 @@ class GroupInvitationManagerImpl extends ConversationClientImpl
 			this.bdfSession = bdfSession;
 		}
 	}
+
+	private static class DeletableSession {
+
+		private final State state;
+		private final List<MessageId> messages = new ArrayList<>();
+
+		private DeletableSession(State state) {
+			this.state = state;
+		}
+	}
 }

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/InviteeState.java

@@ -40,6 +40,11 @@ enum InviteeState implements State {
 		return visibility;
 	}
 
+	@Override
+	public boolean isAwaitingResponse() {
+		return this == INVITED;
+	}
+
 	static InviteeState fromValue(int value) throws FormatException {
 		for (InviteeState s : values()) if (s.value == value) return s;
 		throw new FormatException();

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/PeerState.java

@@ -40,6 +40,11 @@ enum PeerState implements State {
 		return visibility;
 	}
 
+	@Override
+	public boolean isAwaitingResponse() {
+		return false;
+	}
+
 	static PeerState fromValue(int value) throws FormatException {
 		for (PeerState s : values()) if (s.value == value) return s;
 		throw new FormatException();

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/SessionParser.java

@@ -15,6 +15,8 @@ interface SessionParser {
 
 	Role getRole(BdfDictionary d) throws FormatException;
 
+	boolean isSession(BdfDictionary d);
+
 	CreatorSession parseCreatorSession(GroupId contactGroupId, BdfDictionary d)
 			throws FormatException;
 

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/SessionParserImpl.java

@@ -48,6 +48,11 @@ class SessionParserImpl implements SessionParser {
 		return Role.fromValue(d.getLong(SESSION_KEY_ROLE).intValue());
 	}
 
+	@Override
+	public boolean isSession(BdfDictionary d) {
+		return d.getBoolean(SESSION_KEY_IS_SESSION, false);
+	}
+
 	@Override
 	public CreatorSession parseCreatorSession(GroupId contactGroupId,
 			BdfDictionary d) throws FormatException {

briar-core/src/main/java/org/briarproject/briar/privategroup/invitation/State.java

@@ -7,4 +7,6 @@ interface State {
 	int getValue();
 
 	Visibility getVisibility();
+
+	boolean isAwaitingResponse();
 }

briar-core/src/test/java/org/briarproject/briar/privategroup/invitation/GroupInvitationIntegrationTest.java

@@ -31,7 +31,7 @@ import static org.junit.Assert.fail;
 public class GroupInvitationIntegrationTest
 		extends BriarIntegrationTest<BriarIntegrationTestComponent> {
 
-	private PrivateGroup privateGroup0;
+	private PrivateGroup privateGroup;
 	private PrivateGroupManager groupManager0, groupManager1;
 	private GroupInvitationManager groupInvitationManager0,
 			groupInvitationManager1;
@@ -46,12 +46,12 @@ public class GroupInvitationIntegrationTest
 		groupInvitationManager0 = c0.getGroupInvitationManager();
 		groupInvitationManager1 = c1.getGroupInvitationManager();
 
-		privateGroup0 =
+		privateGroup =
 				privateGroupFactory.createPrivateGroup("Testgroup", author0);
 		long joinTime = clock.currentTimeMillis();
 		GroupMessage joinMsg0 = groupMessageFactory
-				.createJoinMessage(privateGroup0.getId(), joinTime, author0);
-		groupManager0.addPrivateGroup(privateGroup0, joinMsg0, true);
+				.createJoinMessage(privateGroup.getId(), joinTime, author0);
+		groupManager0.addPrivateGroup(privateGroup, joinMsg0, true);
 	}
 
 	@Override
@@ -90,21 +90,19 @@ public class GroupInvitationIntegrationTest
 		assertEquals(1, invitations.size());
 		GroupInvitationItem item = invitations.iterator().next();
 		assertEquals(contact0From1, item.getCreator());
-		assertEquals(privateGroup0, item.getShareable());
-		assertEquals(privateGroup0.getId(), item.getId());
-		assertEquals(privateGroup0.getName(), item.getName());
+		assertEquals(privateGroup, item.getShareable());
+		assertEquals(privateGroup.getId(), item.getId());
+		assertEquals(privateGroup.getName(), item.getName());
 		assertFalse(item.isSubscribed());
 
-		Collection<ConversationMessageHeader> messages =
-				db1.transactionWithResult(true, txn -> groupInvitationManager1
-						.getMessageHeaders(txn, contactId0From1));
+		Collection<ConversationMessageHeader> messages = getMessages0From1();
 		assertEquals(1, messages.size());
 		GroupInvitationRequest request =
 				(GroupInvitationRequest) messages.iterator().next();
 		assertEquals(text, request.getText());
 		assertEquals(author0, request.getNameable().getCreator());
 		assertEquals(timestamp, request.getTimestamp());
-		assertEquals(privateGroup0.getName(), request.getNameable().getName());
+		assertEquals(privateGroup.getName(), request.getNameable().getName());
 		assertFalse(request.isLocal());
 		assertFalse(request.isRead());
 		assertFalse(request.canBeOpened());
@@ -120,18 +118,16 @@ public class GroupInvitationIntegrationTest
 		assertFalse(groupInvitationManager1.getInvitations().isEmpty());
 
 		groupInvitationManager1
-				.respondToInvitation(contactId0From1, privateGroup0, false);
+				.respondToInvitation(contactId0From1, privateGroup, false);
 
-		Collection<ConversationMessageHeader> messages =
-				db1.transactionWithResult(true, txn -> groupInvitationManager1
-						.getMessageHeaders(txn, contactId0From1));
+		Collection<ConversationMessageHeader> messages = getMessages0From1();
 		assertEquals(2, messages.size());
 		boolean foundResponse = false;
 		for (ConversationMessageHeader m : messages) {
 			if (m instanceof GroupInvitationResponse) {
 				foundResponse = true;
 				GroupInvitationResponse response = (GroupInvitationResponse) m;
-				assertEquals(privateGroup0.getId(), response.getShareableId());
+				assertEquals(privateGroup.getId(), response.getShareableId());
 				assertTrue(response.isLocal());
 				assertFalse(response.wasAccepted());
 			}
@@ -140,16 +136,14 @@ public class GroupInvitationIntegrationTest
 
 		sync1To0(1, true);
 
-		messages = db0.transactionWithResult(true, txn ->
-				groupInvitationManager0
-						.getMessageHeaders(txn, contactId1From0));
+		messages = getMessages1From0();
 		assertEquals(2, messages.size());
 		foundResponse = false;
 		for (ConversationMessageHeader m : messages) {
 			if (m instanceof GroupInvitationResponse) {
 				foundResponse = true;
 				GroupInvitationResponse response = (GroupInvitationResponse) m;
-				assertEquals(privateGroup0.getId(), response.getShareableId());
+				assertEquals(privateGroup.getId(), response.getShareableId());
 				assertFalse(response.isLocal());
 				assertFalse(response.wasAccepted());
 			}
@@ -168,9 +162,7 @@ public class GroupInvitationIntegrationTest
 		sendInvitation(timestamp, null);
 
 		// check that invitation message state is correct
-		Collection<ConversationMessageHeader> messages =
-				db0.transactionWithResult(true, txn -> groupInvitationManager0
-						.getMessageHeaders(txn, contactId1From0));
+		Collection<ConversationMessageHeader> messages = getMessages1From0();
 		assertEquals(1, messages.size());
 		assertMessageState(messages.iterator().next(), true, false, false);
 
@@ -178,11 +170,9 @@ public class GroupInvitationIntegrationTest
 		assertFalse(groupInvitationManager1.getInvitations().isEmpty());
 
 		groupInvitationManager1
-				.respondToInvitation(contactId0From1, privateGroup0, true);
+				.respondToInvitation(contactId0From1, privateGroup, true);
 
-		messages = db1.transactionWithResult(true,
-				txn -> groupInvitationManager1
-						.getMessageHeaders(txn, contactId0From1));
+		messages = getMessages0From1();
 		assertEquals(2, messages.size());
 		boolean foundResponse = false;
 		for (ConversationMessageHeader m : messages) {
@@ -190,11 +180,11 @@ public class GroupInvitationIntegrationTest
 				foundResponse = true;
 				GroupInvitationResponse response = (GroupInvitationResponse) m;
 				assertMessageState(response, true, false, false);
-				assertEquals(privateGroup0.getId(), response.getShareableId());
+				assertEquals(privateGroup.getId(), response.getShareableId());
 				assertTrue(response.wasAccepted());
 			} else {
 				GroupInvitationRequest request = (GroupInvitationRequest) m;
-				assertEquals(privateGroup0, request.getNameable());
+				assertEquals(privateGroup, request.getNameable());
 				assertTrue(request.wasAnswered());
 				assertTrue(request.canBeOpened());
 			}
@@ -203,16 +193,14 @@ public class GroupInvitationIntegrationTest
 
 		sync1To0(1, true);
 
-		messages = db1.transactionWithResult(true, txn ->
-				groupInvitationManager0
-						.getMessageHeaders(txn, contactId1From0));
+		messages = getMessages1From0();
 		assertEquals(2, messages.size());
 		foundResponse = false;
 		for (ConversationMessageHeader m : messages) {
 			if (m instanceof GroupInvitationResponse) {
 				foundResponse = true;
 				GroupInvitationResponse response = (GroupInvitationResponse) m;
-				assertEquals(privateGroup0.getId(), response.getShareableId());
+				assertEquals(privateGroup.getId(), response.getShareableId());
 				assertTrue(response.wasAccepted());
 			}
 		}
@@ -223,7 +211,7 @@ public class GroupInvitationIntegrationTest
 		// group was added
 		Collection<PrivateGroup> groups = groupManager1.getPrivateGroups();
 		assertEquals(1, groups.size());
-		assertEquals(privateGroup0, groups.iterator().next());
+		assertEquals(privateGroup, groups.iterator().next());
 	}
 
 	@Test
@@ -240,12 +228,10 @@ public class GroupInvitationIntegrationTest
 		// 1 has one unread message
 		Group g0 = groupInvitationManager1.getContactGroup(contact0From1);
 		assertGroupCount(messageTracker1, g0.getId(), 1, 1, timestamp);
-		ConversationMessageHeader m = db1.transactionWithResult(true, txn ->
-				groupInvitationManager1.getMessageHeaders(txn, contactId0From1)
-						.iterator().next());
+		ConversationMessageHeader m = getMessages0From1().iterator().next();
 
 		groupInvitationManager1
-				.respondToInvitation(contactId0From1, privateGroup0, true);
+				.respondToInvitation(contactId0From1, privateGroup, true);
 
 		// 1 has two messages, one still unread
 		assertGroupCount(messageTracker1, g0.getId(), 2, 1);
@@ -266,28 +252,28 @@ public class GroupInvitationIntegrationTest
 
 		// invitation is not allowed before the first hasn't been answered
 		assertFalse(groupInvitationManager0
-				.isInvitationAllowed(contact1From0, privateGroup0.getId()));
+				.isInvitationAllowed(contact1From0, privateGroup.getId()));
 
 		// deliver invitation and response
 		sync0To1(1, true);
 		groupInvitationManager1
-				.respondToInvitation(contactId0From1, privateGroup0, false);
+				.respondToInvitation(contactId0From1, privateGroup, false);
 		sync1To0(1, true);
 
 		// after invitation was declined, inviting again is possible
 		assertTrue(groupInvitationManager0
-				.isInvitationAllowed(contact1From0, privateGroup0.getId()));
+				.isInvitationAllowed(contact1From0, privateGroup.getId()));
 
 		// send and accept the second invitation
 		sendInvitation(clock.currentTimeMillis(), "Second Invitation");
 		sync0To1(1, true);
 		groupInvitationManager1
-				.respondToInvitation(contactId0From1, privateGroup0, true);
+				.respondToInvitation(contactId0From1, privateGroup, true);
 		sync1To0(1, true);
 
 		// invitation is not allowed since the member joined the group now
 		assertFalse(groupInvitationManager0
-				.isInvitationAllowed(contact1From0, privateGroup0.getId()));
+				.isInvitationAllowed(contact1From0, privateGroup.getId()));
 
 		// don't allow another invitation request
 		try {
@@ -305,14 +291,14 @@ public class GroupInvitationIntegrationTest
 		sync0To1(1, true);
 
 		groupInvitationManager1
-				.respondToInvitation(contactId0From1, privateGroup0, false);
+				.respondToInvitation(contactId0From1, privateGroup, false);
 		sync1To0(1, true);
 
 		sendInvitation(timestamp, "Second Invitation");
 		sync0To1(1, true);
 
 		groupInvitationManager1
-				.respondToInvitation(contactId0From1, privateGroup0, true);
+				.respondToInvitation(contactId0From1, privateGroup, true);
 	}
 
 	@Test(expected = ProtocolStateException.class)
@@ -325,7 +311,7 @@ public class GroupInvitationIntegrationTest
 
 		// Creator leaves group
 		assertEquals(1, groupManager0.getPrivateGroups().size());
-		groupManager0.removePrivateGroup(privateGroup0.getId());
+		groupManager0.removePrivateGroup(privateGroup.getId());
 		assertEquals(0, groupManager0.getPrivateGroups().size());
 
 		// Creator's leave message is delivered to invitee
@@ -335,7 +321,7 @@ public class GroupInvitationIntegrationTest
 		// thrown as the action has failed
 		assertEquals(0, groupManager1.getPrivateGroups().size());
 		groupInvitationManager1
-				.respondToInvitation(contactId0From1, privateGroup0, true);
+				.respondToInvitation(contactId0From1, privateGroup, true);
 	}
 
 	@Test
@@ -348,7 +334,7 @@ public class GroupInvitationIntegrationTest
 
 		// Creator leaves group
 		assertEquals(1, groupManager0.getPrivateGroups().size());
-		groupManager0.removePrivateGroup(privateGroup0.getId());
+		groupManager0.removePrivateGroup(privateGroup.getId());
 		assertEquals(0, groupManager0.getPrivateGroups().size());
 
 		// Creator's leave message is delivered to invitee
@@ -361,7 +347,7 @@ public class GroupInvitationIntegrationTest
 		// as the action has succeeded
 		assertEquals(0, groupManager1.getPrivateGroups().size());
 		groupInvitationManager1
-				.respondToInvitation(contactId0From1, privateGroup0, false);
+				.respondToInvitation(contactId0From1, privateGroup, false);
 	}
 
 	@Test
@@ -375,15 +361,15 @@ public class GroupInvitationIntegrationTest
 
 		// Creator leaves group
 		assertEquals(1, groupManager0.getPrivateGroups().size());
-		groupManager0.removePrivateGroup(privateGroup0.getId());
+		groupManager0.removePrivateGroup(privateGroup.getId());
 		assertEquals(0, groupManager0.getPrivateGroups().size());
 
 		// Invitee accepts invitation
 		assertEquals(0, groupManager1.getPrivateGroups().size());
 		groupInvitationManager1
-				.respondToInvitation(contactId0From1, privateGroup0, true);
+				.respondToInvitation(contactId0From1, privateGroup, true);
 		assertEquals(1, groupManager1.getPrivateGroups().size());
-		assertFalse(groupManager1.isDissolved(privateGroup0.getId()));
+		assertFalse(groupManager1.isDissolved(privateGroup.getId()));
 
 		// Invitee's join message is delivered to creator
 		sync1To0(1, true);
@@ -392,7 +378,7 @@ public class GroupInvitationIntegrationTest
 		sync0To1(1, true);
 
 		// Group is marked as dissolved
-		assertTrue(groupManager1.isDissolved(privateGroup0.getId()));
+		assertTrue(groupManager1.isDissolved(privateGroup.getId()));
 	}
 
 	@Test
@@ -406,13 +392,13 @@ public class GroupInvitationIntegrationTest
 
 		// Creator leaves group
 		assertEquals(1, groupManager0.getPrivateGroups().size());
-		groupManager0.removePrivateGroup(privateGroup0.getId());
+		groupManager0.removePrivateGroup(privateGroup.getId());
 		assertEquals(0, groupManager0.getPrivateGroups().size());
 
 		// Invitee declines invitation
 		assertEquals(0, groupManager1.getPrivateGroups().size());
 		groupInvitationManager1
-				.respondToInvitation(contactId0From1, privateGroup0, false);
+				.respondToInvitation(contactId0From1, privateGroup, false);
 		assertEquals(0, groupManager1.getPrivateGroups().size());
 
 		// Invitee's leave message is delivered to creator
@@ -434,7 +420,7 @@ public class GroupInvitationIntegrationTest
 		// Invitee responds to invitation
 		assertEquals(0, groupManager1.getPrivateGroups().size());
 		groupInvitationManager1
-				.respondToInvitation(contactId0From1, privateGroup0, true);
+				.respondToInvitation(contactId0From1, privateGroup, true);
 		assertEquals(1, groupManager1.getPrivateGroups().size());
 
 		// Invitee's (sharing) join message is delivered to creator
@@ -448,11 +434,11 @@ public class GroupInvitationIntegrationTest
 
 		// Creator leaves group
 		assertEquals(1, groupManager0.getPrivateGroups().size());
-		groupManager0.removePrivateGroup(privateGroup0.getId());
+		groupManager0.removePrivateGroup(privateGroup.getId());
 		assertEquals(0, groupManager0.getPrivateGroups().size());
 
 		// Invitee leaves group
-		groupManager1.removePrivateGroup(privateGroup0.getId());
+		groupManager1.removePrivateGroup(privateGroup.getId());
 		assertEquals(0, groupManager1.getPrivateGroups().size());
 
 		// Creator's leave message is delivered to invitee
@@ -462,13 +448,148 @@ public class GroupInvitationIntegrationTest
 		sync1To0(1, true);
 	}
 
+	@Test
+	public void testDeletingAllMessagesWhenCompletingSession()
+			throws Exception {
+		// send invitation
+		sendInvitation(clock.currentTimeMillis(), null);
+		sync0To1(1, true);
+
+		// messages can not be deleted
+		assertFalse(deleteAllMessages1From0());
+		assertEquals(1, getMessages1From0().size());
+		assertFalse(deleteAllMessages0From1());
+		assertEquals(1, getMessages0From1().size());
+
+		// respond
+		groupInvitationManager1
+				.respondToInvitation(contactId0From1, privateGroup, true);
+		sync1To0(1, true);
+
+		// check group count
+		Group g1From0 = groupInvitationManager0.getContactGroup(contact1From0);
+		Group g0From1 = groupInvitationManager1.getContactGroup(contact0From1);
+		assertGroupCount(messageTracker0, g1From0.getId(), 2, 1);
+		assertGroupCount(messageTracker1, g0From1.getId(), 2, 1);
+
+		// messages can be deleted now by creator, invitee needs to wait for ACK
+		assertTrue(deleteAllMessages1From0());
+		assertEquals(0, getMessages1From0().size());
+		assertTrue(deleteAllMessages1From0());  // a second time nothing happens
+		assertGroupCount(messageTracker0, g1From0.getId(), 0, 0);
+
+		// trying to delete fails for invitee
+		assertFalse(deleteAllMessages0From1());
+		assertEquals(2, getMessages0From1().size());
+
+		// creator sends JOIN message and ACK for response
+		sync0To1(1, true);
+
+		// now invitee can also delete messages
+		assertTrue(deleteAllMessages0From1());
+		assertEquals(0, getMessages0From1().size());
+		assertTrue(deleteAllMessages0From1());  // a second time nothing happens
+		assertGroupCount(messageTracker1, g0From1.getId(), 0, 0);
+
+		// invitee now leaves
+		groupManager1.removePrivateGroup(privateGroup.getId());
+		sync1To0(1, true);
+
+		// no new messages to delete
+		assertEquals(0, getMessages1From0().size());
+		assertEquals(0, getMessages0From1().size());
+	}
+
+	@Test
+	public void testDeletingAllMessagesWhenDeclining() throws Exception {
+		// send invitation
+		sendInvitation(clock.currentTimeMillis(), null);
+		sync0To1(1, true);
+
+		// respond
+		groupInvitationManager1
+				.respondToInvitation(contactId0From1, privateGroup, false);
+		sync1To0(1, true);
+
+		// check group count
+		Group g1From0 = groupInvitationManager0.getContactGroup(contact1From0);
+		Group g0From1 = groupInvitationManager1.getContactGroup(contact0From1);
+		assertGroupCount(messageTracker0, g1From0.getId(), 2, 1);
+		assertGroupCount(messageTracker1, g0From1.getId(), 2, 1);
+
+		// messages can be deleted now by creator, invitee needs to wait for ACK
+		assertTrue(deleteAllMessages1From0());
+		assertEquals(0, getMessages1From0().size());
+		assertTrue(deleteAllMessages1From0());  // a second time nothing happens
+
+		// trying to delete fails for invitee
+		assertFalse(deleteAllMessages0From1());
+		assertEquals(2, getMessages0From1().size());
+
+		// creator sends ACK
+		sendAcks(c0, c1, contactId1From0, 1);
+
+		// now invitee can also delete messages
+		assertTrue(deleteAllMessages0From1());
+		assertEquals(0, getMessages0From1().size());
+		assertTrue(deleteAllMessages0From1());  // a second time nothing happens
+		assertGroupCount(messageTracker1, g0From1.getId(), 0, 0);
+
+		// creator can re-invite
+		sendInvitation(clock.currentTimeMillis(), null);
+		sync0To1(1, true);
+
+		// now new messages can not be deleted anymore
+		assertFalse(deleteAllMessages1From0());
+		assertFalse(deleteAllMessages0From1());
+
+		// responding again
+		groupInvitationManager1
+				.respondToInvitation(contactId0From1, privateGroup, false);
+		sync1To0(1, true);
+
+		// creator sends ACK
+		sendAcks(c0, c1, contactId1From0, 1);
+
+		// asserting group counts
+		assertGroupCount(messageTracker1, g0From1.getId(), 2, 1);
+		assertGroupCount(messageTracker0, g1From0.getId(), 2, 1);
+
+		// deleting is possible again
+		assertTrue(deleteAllMessages1From0());
+		assertTrue(deleteAllMessages0From1());
+		assertGroupCount(messageTracker1, g0From1.getId(), 0, 0);
+		assertGroupCount(messageTracker0, g1From0.getId(), 0, 0);
+	}
+
+	private Collection<ConversationMessageHeader> getMessages1From0()
+			throws DbException {
+		return db0.transactionWithResult(true, txn -> groupInvitationManager0
+				.getMessageHeaders(txn, contactId1From0));
+	}
+
+	private Collection<ConversationMessageHeader> getMessages0From1()
+			throws DbException {
+		return db1.transactionWithResult(true, txn -> groupInvitationManager1
+				.getMessageHeaders(txn, contactId0From1));
+	}
+
+	private boolean deleteAllMessages1From0() throws DbException {
+		return db0.transactionWithResult(false, txn -> groupInvitationManager0
+				.deleteAllMessages(txn, contactId1From0));
+	}
+
+	private boolean deleteAllMessages0From1() throws DbException {
+		return db1.transactionWithResult(false, txn -> groupInvitationManager1
+				.deleteAllMessages(txn, contactId0From1));
+	}
+
 	private void sendInvitation(long timestamp, @Nullable String text)
 			throws DbException {
 		byte[] signature = groupInvitationFactory.signInvitation(contact1From0,
-				privateGroup0.getId(), timestamp, author0.getPrivateKey());
-		groupInvitationManager0
-				.sendInvitation(privateGroup0.getId(), contactId1From0, text,
-						timestamp, signature);
+				privateGroup.getId(), timestamp, author0.getPrivateKey());
+		groupInvitationManager0.sendInvitation(privateGroup.getId(),
+				contactId1From0, text, timestamp, signature);
 	}
 
 }