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MXRoomSummary: Reimplement fetchLastMessage
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to avoid any synchronous decryption.

The algo is probably simpler.

It also fixes testGetLastMessageFromPagination, testGetLastMessageFromSeveralPaginations and testFixRoomsSummariesLastMessage tests that have been broken since b4d5ba7
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@manuroe
manuroe committed May 12, 2021
1 parent b8613d5 commit 6bfeee5
Showing 1 changed file with 58 additions and 120 deletions.
178 changes: 58 additions & 120 deletions MatrixSDK/Data/MXRoomSummary.m
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Original file line number Diff line number Diff line change
Expand Up @@ -257,25 +257,30 @@ - (MXHTTPOperation *)resetLastMessage:(void (^)(void))complete failure:(void (^)
_lastMessageAttributedString = nil;
[_lastMessageOthers removeAllObjects];

return [self fetchLastMessage:complete failure:failure lastEventIdChecked:nil operation:nil commit:commit];
return [self fetchLastMessage:complete failure:failure liveTimeline:nil onlyFromStore:YES operation:nil commit:commit];
}

/**
Find the event to be used as last message.
Find recursively the event to be used as last message.
@param complete A block object called when the operation completes.
@param failure A block object called when the operation fails.
@param lastEventIdChecked the id of the last candidate event checked to be the last message.
Nil means we will start checking from the last event in the store.
@param liveTimeline the timeline to use to paginate and get more events.
@param onlyFromStore YES for the first call. For quickness, we want to avoid any HTTP requests at first.
@param operation the current http operation if any.
The method may need several requests before fetching the right last message.
If it happens, the first one is mutated to the others with [MXHTTPOperation mutateTo:].
@param commit tell whether the updated room summary must be committed to the store. Use NO when a more
global [MXStore commit] will happen. This optimises IO.
global [MXStore commit] will happen. This optimises IO.
@return a MXHTTPOperation
*/
- (MXHTTPOperation *)fetchLastMessage:(void (^)(void))complete failure:(void (^)(NSError *))failure lastEventIdChecked:(NSString*)lastEventIdChecked operation:(MXHTTPOperation *)operation commit:(BOOL)commit
- (MXHTTPOperation *)fetchLastMessage:(void (^)(void))complete
failure:(void (^)(NSError *))failure
liveTimeline:(MXEventTimeline *)liveTimeline
onlyFromStore:(BOOL)onlyFromStore
operation:(MXHTTPOperation *)operation commit:(BOOL)commit
{
// Sanity checks
MXRoom *room = self.room;
if (!room)
{
Expand All @@ -291,126 +296,59 @@ - (MXHTTPOperation *)fetchLastMessage:(void (^)(void))complete failure:(void (^)
// Create an empty operation that will be mutated later
operation = [[MXHTTPOperation alloc] init];
}

MXWeakify(self);
[self.room state:^(MXRoomState *roomState) {
MXStrongifyAndReturnIfNil(self);

// Start by checking events we have in the store
MXRoomState *state = roomState;
id<MXEventsEnumerator> messagesEnumerator = room.enumeratorForStoredMessages;
NSUInteger messagesInStore = messagesEnumerator.remaining;
MXEvent *event = messagesEnumerator.nextEvent;
NSString *lastEventIdCheckedInBlock = lastEventIdChecked;

// 1.1 Find where we stopped at the previous call in the fetchLastMessage calls loop
BOOL firstIteration = YES;
if (lastEventIdCheckedInBlock)
// Get the room timeline
if (!liveTimeline)
{
[room liveTimeline:^(MXEventTimeline *liveTimeline) {
[liveTimeline resetPagination];
[self fetchLastMessage:complete failure:failure liveTimeline:liveTimeline onlyFromStore:onlyFromStore operation:operation commit:commit];
}];
return operation;
}

// Make sure we can still paginate
if (![liveTimeline canPaginate:MXTimelineDirectionBackwards])
{
if (complete)
{
firstIteration = NO;
while (event)
{
NSString *eventId = event.eventId;

event = messagesEnumerator.nextEvent;

if ([eventId isEqualToString:lastEventIdCheckedInBlock])
{
break;
}
}
complete();
}

// 1.2 Check events one by one until finding the right last message for the room
BOOL lastMessageUpdated = NO;
while (event)
return operation;
}

// Process every message received by back pagination
__block BOOL lastMessageUpdated = NO;
[liveTimeline listenToEvents:^(MXEvent *event, MXTimelineDirection direction, MXRoomState *eventState) {
if (direction == MXTimelineDirectionBackwards
&& !lastMessageUpdated)
{
// Decrypt the event if necessary
if (event.eventType == MXEventTypeRoomEncrypted)
{
if (![self.mxSession decryptEvent:event inTimeline:nil])
{
NSLog(@"[MXRoomSummary] fetchLastMessage: Warning: Unable to decrypt event: %@\nError: %@", event.content[@"body"], event.decryptionError);
}
}

if (event.isState)
{
// Need to go backward in the state to provide it as it was when the event occured
if (state.isLive)
{
state = [state copy];
state.isLive = NO;
}

[state handleStateEvents:@[event]];
}

lastEventIdCheckedInBlock = event.eventId;

// Propose the event as last message
lastMessageUpdated = [self.mxSession.roomSummaryUpdateDelegate session:self.mxSession updateRoomSummary:self withLastEvent:event eventState:state roomState:roomState];
if (lastMessageUpdated)
{
// The event is accepted. We have our last message
// The roomSummaryUpdateDelegate has stored the _lastMessageEventId
break;
}

event = messagesEnumerator.nextEvent;
lastMessageUpdated = [self.mxSession.roomSummaryUpdateDelegate session:self.mxSession updateRoomSummary:self withLastEvent:event eventState:eventState roomState:liveTimeline.state];
}

// 2.1 If lastMessageEventId is still nil, fetch events from the homeserver
MXWeakify(self);
[room liveTimeline:^(MXEventTimeline *liveTimeline) {
MXStrongifyAndReturnIfNil(self);

if (!self->_lastMessageEventId && [liveTimeline canPaginate:MXTimelineDirectionBackwards])
{
NSUInteger messagesToPaginate = 30;

// Reset pagination the first time
if (firstIteration)
{
[liveTimeline resetPagination];

// Make sure we paginate more than the events we have already in the store
messagesToPaginate += messagesInStore;
}

// Paginate events from the homeserver
// XXX: Pagination on the timeline may conflict with request from the app
__block MXHTTPOperation *newOperation;
newOperation = [liveTimeline paginate:messagesToPaginate direction:MXTimelineDirectionBackwards onlyFromStore:NO complete:^{

// Received messages have been stored in the store. We can make a new loop
// XXX: This is only true for a permanent storage. Only MXNoStore is not permanent.
// MXNoStore is only used for tests. We can skip it here.
if (self.mxSession.store.isPermanent)
{
[self fetchLastMessage:complete failure:failure
lastEventIdChecked:lastEventIdCheckedInBlock
operation:(operation ? operation : newOperation)
commit:commit];
}

} failure:failure];

// Update the current HTTP operation
[operation mutateTo:newOperation];
}
else
}];

// Back paginate. First only from the store. Then, allow pagination requests to the homeserver
MXHTTPOperation *newOperation = [liveTimeline paginate:30 direction:MXTimelineDirectionBackwards onlyFromStore:onlyFromStore complete:^{
if (lastMessageUpdated)
{
// We are done
[self save:commit];

if (complete)
{
if (complete)
{
complete();
}

[self save:commit];
complete();
}
}];
}];

}
else
{
// Need more message
[self fetchLastMessage:complete failure:failure liveTimeline:liveTimeline onlyFromStore:NO operation:operation commit:commit];
}

} failure:failure];

[operation mutateTo:newOperation];

return operation;
}

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