BF: When the last message is redacted, [MXKRecentCellData update] mak…

…es paginations loops element-hq/element-ios#520

Use the new MXEventsEnumerator from MatrixSDK to find the right last message to display.

MatrixKit/Models/Room/MXKRoomDataSource.h

@@ -119,11 +119,6 @@ extern NSString *const kMXKRoomDataSourceSyncStatusChanged;
  */
 @property (nonatomic, readonly) BOOL isPeeking;
 
-/**
- The last event in the room that matches the `eventsFilterForMessages` property.
- */
-@property (nonatomic, readonly) MXEvent *lastMessage;
-
 /**
  The list of the attachments with thumbnail in the current available bubbles (MXKAttachment instances).
  */
@@ -475,4 +470,19 @@ extern NSString *const kMXKRoomDataSourceSyncStatusChanged;
  */
 - (void)handleUnsentMessages;
 
+/**
+ The last event in the room.
+ 
+ This event must match several criteria:
+ - its type must be in `eventsFilterForMessages`
+ - it must follow the mxSession.ignoreProfileChangesDuringLastMessageProcessing
+ setting
+ - it must be displayable, ie the passed eventFormatter must return a non empty
+ string for it
+
+ @param eventFormatter the event formatter in order to check the displayability of events.
+ @param onComplete a block call when the operation completes. The provided lastMessage can be nil.
+ */
+- (void)lastMessageWithEventFormatter:(MXKEventFormatter*)eventFormatter onComplete:(void(^)(MXEvent *lastMessage))onComplete;
+
 @end

MatrixKit/Models/Room/MXKRoomDataSource.m

@@ -97,6 +97,11 @@ Current pagination request (if any)
  */
  MXPeekingRoom *peekingRoom;
 
+ /**
+ The cache for the last message returned by [self lastMessageWithEventFormatter:]
+ */
+ MXEvent *lastMessage;
+
  /**
  Observe UIApplicationSignificantTimeChangeNotification to trigger cell change on time formatting change.
  */
@@ -378,6 +383,7 @@ - (void)reset
 
  [bubbles removeAllObjects];
  [eventIdToBubbleMap removeAllObjects];
+ lastMessage = nil;
 
  _room = nil;
  }
@@ -447,6 +453,7 @@ - (void)destroy
 
  eventsToProcess = nil;
  bubbles = nil;
+ lastMessage = nil;
  eventIdToBubbleMap = nil;
 
  [_timeline destroy];
@@ -583,50 +590,6 @@ - (void)didMXSessionStateChange
  }
 }
 
-- (MXEvent *)lastMessage
-{
- MXEvent *lastMessage;
-
- // Look for the most recent message (ignore events without timestamp).
- id<MXKRoomBubbleCellDataStoring> bubbleData;
- @synchronized(bubbles)
- {
- NSInteger index = bubbles.count;
- while (index--)
- {
- bubbleData = bubbles[index];
- if (bubbleData.date)
- {
- break;
- }
- }
- }
-
- if (bubbleData)
- {
- NSInteger index = bubbleData.events.count;
- while (index--)
- {
- lastMessage = bubbleData.events[index];
- if (lastMessage.originServerTs != kMXUndefinedTimestamp)
- {
- break;
- }
- lastMessage = nil;
- }
- }
-
- if (!lastMessage)
- {
- // Use here the stored data for this room
- lastMessage = [_room lastMessageWithTypeIn:_eventsFilterForMessages];
-
- // Check if this event is a bing event
- [self checkBing:lastMessage];
- }
- return lastMessage;
-}
-
 - (NSArray *)attachmentsWithThumbnail
 {
  NSMutableArray *attachments = [NSMutableArray array];
@@ -730,13 +693,13 @@ - (void)setEventsFilterForMessages:(NSArray *)eventsFilterForMessages
  {
  BOOL shouldRemoveBubbleData = NO;
  BOOL hasChanged = NO;
-
+ MXEvent *redactedEvent = nil;
+
  @synchronized (bubbleData)
  {
  // Retrieve the original event to redact it
  NSArray *events = bubbleData.events;
- MXEvent *redactedEvent = nil;
-
+
  for (MXEvent *event in events)
  {
  if ([event.eventId isEqualToString:redactionEvent.redacts])
@@ -774,7 +737,13 @@ - (void)setEventsFilterForMessages:(NSArray *)eventsFilterForMessages
  {
  // Update the delegate on main thread
  dispatch_async(dispatch_get_main_queue(), ^{
-
+
+ // Reset lastMessage if it has been redacted
+ if ([lastMessage.eventId isEqualToString:redactedEvent.eventId])
+ {
+ lastMessage = nil;
+ }
+
  if (self.delegate)
  {
  [self.delegate dataSource:self didCellChange:nil];
@@ -1813,6 +1782,12 @@ - (void)removeEventWithEventId:(NSString *)eventId
 
  // Remove the event from the outgoing messages storage
  [_room removeOutgoingMessage:eventId];
+
+ // Reset lastMessage if it has been removed
+ if ([lastMessage.eventId isEqualToString:eventId])
+ {
+ lastMessage = nil;
+ }
 
  // Update the delegate
  if (self.delegate)
@@ -1877,6 +1852,98 @@ - (void)handleUnsentMessages
  }
 }
 
+- (void)lastMessageWithEventFormatter:(MXKEventFormatter*)eventFormatter onComplete:(void(^)(MXEvent *))onComplete
+{
+ // The last message can
+
+ // Firstly, check if it has been cached
+ if (lastMessage)
+ {
+ NSLog(@"lastMessage: case #1 for %@", self.roomId);
+ onComplete(lastMessage);
+ return;
+ }
+
+ MXEvent *lastDisplayableEvent;
+ MXEvent *event;
+ MXKEventFormatterError *error;
+
+ // Secondly, search for a matching event in the outgoing messages
+ id<MXEventsEnumerator> enumerator = [[MXEventsByTypesEnumeratorOnArray alloc] initWithMessages:_room.outgoingMessages
+ andTypesIn:self.eventsFilterForMessages
+ ignoreMemberProfileChanges:self.mxSession.ignoreProfileChangesDuringLastMessageProcessing];
+ while ((event = enumerator.nextEvent))
+ {
+ // Check that the event formatter can display the event
+ NSString *eventTextMessage = [eventFormatter stringFromEvent:event withRoomState:_room.state error:&error];
+ if (eventTextMessage.length)
+ {
+ lastDisplayableEvent = event;
+ NSLog(@"lastMessage: case #2 for %@", self.roomId);
+ break;
+ }
+ }
+
+ if (!lastDisplayableEvent)
+ {
+ // Thirdly, search for a matching event in the messages already in the store
+ // for this room
+ enumerator = [self.room enumeratorForStoredMessagesWithTypeIn:self.eventsFilterForMessages
+ ignoreMemberProfileChanges:self.mxSession.ignoreProfileChangesDuringLastMessageProcessing];
+
+ while ((event = enumerator.nextEvent))
+ {
+ // Check that the event formatter can display the event
+ NSString *eventTextMessage = [eventFormatter stringFromEvent:event withRoomState:_room.state error:&error];
+ if (eventTextMessage.length)
+ {
+ lastDisplayableEvent = event;
+ NSLog(@"lastMessage: case #3 for %@", self.roomId);
+ break;
+ }
+ }
+ }
+
+ if (lastDisplayableEvent)
+ {
+ // Cache it for future reuse
+ lastMessage = lastDisplayableEvent;
+ onComplete(lastDisplayableEvent);
+ }
+ else
+ {
+ if ([_timeline canPaginate: MXTimelineDirectionBackwards])
+ {
+ // Finally, as there is no matching events locally, get more messages from 
+ // the homeserver
+ NSLog(@"lastMessage: case #4 for %@", self.roomId);
+
+ // Trigger asynchronously this back pagination to not block the UI thread.
+ dispatch_async(dispatch_get_main_queue(), ^{
+
+ // Make the data source load more messages than available in the store to
+ // force it to get them from the homeserver
+ [self paginate:(self.room.storedMessagesCount + 30) direction:MXTimelineDirectionBackwards onlyFromStore:NO success:^(NSUInteger addedCellNumber) {
+
+ [self lastMessageWithEventFormatter:eventFormatter onComplete:onComplete];
+
+ } failure:^(NSError *error) {
+
+ onComplete(nil);
+
+ }];
+ });
+ }
+ else
+ {
+ // All the room history has been loaded locally but no message matches the
+ // criteria
+ NSLog(@"lastMessage: case #5 for %@", self.roomId);
+ onComplete(nil);
+ }
+ }
+}
+
 #pragma mark - Private methods
 - (MXEvent*)addLocalEchoForMessageContent:(NSDictionary*)msgContent
 {
@@ -1965,6 +2032,15 @@ - (void)replaceLocalEcho:(MXEvent*)localEcho withEvent:(MXEvent*)event
  {
  [self removeCellData:bubbleData];
  }
+
+ // Update lastMessage if it has been replaced
+ if ([lastMessage.eventId isEqualToString:localEcho.eventId])
+ {
+ // The new event should have the same characteristics as localEcho: it should
+ // match [self lastMessageWithEventFormatter:] criteria and can replace it as
+ // as the last message
+ lastMessage = event;
+ }
 
  // Update the delegate
  if (self.delegate)
@@ -2188,6 +2264,7 @@ - (void)processQueuedEvents:(void (^)(NSUInteger addedHistoryCellNb, NSUInteger
  NSUInteger serverSyncEventCount = 0;
  NSUInteger addedHistoryCellCount = 0;
  NSUInteger addedLiveCellCount = 0;
+ BOOL lastMessageHasChanged = NO;
 
  // Lock on `eventsToProcessSnapshot` to suspend reload or destroy during the process.
  @synchronized(eventsToProcessSnapshot)
@@ -2371,6 +2448,12 @@ - (void)processQueuedEvents:(void (^)(NSUInteger addedHistoryCellNb, NSUInteger
  eventIdToBubbleMap[queuedEvent.event.eventId] = bubbleData;
  }
  }
+
+ if (queuedEvent.direction == MXTimelineDirectionForwards)
+ {
+ // There is a new last message
+ lastMessageHasChanged = YES;
+ }
  }
  }
  eventsToProcessSnapshot = nil;
@@ -2382,7 +2465,13 @@ - (void)processQueuedEvents:(void (^)(NSUInteger addedHistoryCellNb, NSUInteger
  // Updated data can be displayed now
  // Block MXKRoomDataSource.processingQueue while the processing is finalised on the main thread
  dispatch_sync(dispatch_get_main_queue(), ^{
-
+
+ // Reset the last message cache if new live events have been received
+ if (lastMessageHasChanged)
+ {
+ lastMessage = nil;
+ }
+
  // Check whether self has not been reloaded or destroyed
  if (self.state == MXKDataSourceStateReady && bubblesSnapshot)
  {