... and add some sanity checks
Two things here:
1. Clean up the Room API for adding new events to the timeline. Where before
we had addEvents and addEventsToTimeline, whose purposes were unclear, we now
have addLiveEvents which must be used for adding events to the end of the live
timeline, and addEventsToTimeline which should be used for pagination (either
back-pagination of the live timeline, or pagination of an old timeline).
2. Add some sanity checks for the live timeline. Today we have seen problems
where somehow the live timeline had gained a forward pagination token, or the
live timeline had got joined to another timeline, leading to much confusion -
and I would like to notice these sooner.
The existing 'pendingEventOrdering'=='end' semantics had been substantially
broken by the introduction of timelines and gappy syncs: after a gappy
sync, pending events would get stuck in the old timeline section. (Part of
https://github.com/vector-im/vector-web/issues/1120).
This is some preparatory work for fixing up the problems with te timeline
ordering of unsent messages
(https://github.com/vector-im/vector-web/issues/1120). The functional changes
here should be minimal (bar an extra `Room.localEchoUpdated` when the local
echo is first added to the timeline).
Give `MatrixClient.sendEvent` its own entry point `Room.addPendingMessage`
instead of pushing it through `addEventsToTimeline`; this considerably
simplifies the implementation of the latter and also means that we can contain
the `_txnId` ming to MatrixClient.
Move the code which deals with a successful `/send` response from
`MatrixClient` into `Room.updatePendingEvent`, since it involves fiddling with
the innards of the Room.
Also adds a new EventStatus 'SENT' for events which have been successfully sent
but whose remote echo we still haven't received.
We need to reset things at the UI level when we get a gappy sync, so give the
clients something to listen for.
Also add a bunch of tests for that bit of code.
In order to resolve the conflict between local and remote read-receipts, try to
give precedence to the read-receipt which refers to the most recent event.
Also fix the read-receipt synthesis in _addLiveEvents so that it actually works
(drop the spurious MatrixEvent wrapper), and remove the synthesis in
recalculate() (which appears to be redundant).
This provides optional support for fetching old events via the /context API,
and paginating backwards and forwards from them, eventually merging into the
live timeline.
To support it, events are now stored in an EventTimeline, rather than directly
in an array in the Room; the old names are maintained as references for
compatibility.
The feature has to be enabled explicitly, otherwise it would be impossible for
existing clients to back-paginate to the old events after a gappy /sync.
Still TODO here:
* An object which provides a window into the timelines to make them possible to
use. This will be a separate PR.
* Rewrite the 'EventContext' used by the searchRoomEvents API in terms of an
EventTimeline - it is essentially a subset.
Add polyfills for Array.map/filter according to MDN because it looks much
better than the utils format.
Add stub tests for edge cases and implement test for the common case.
This makes it easier to localise in the future (if name == '?'), whilst
still indicating an unknown name. Ideally we would be returning null, but
this would require null checks every time the room name was accessed, which
isn't ideal. This also makes the UT for this less brittle (rather than
comparing literal english strings which are prone to breakage when we
inevitably change 'Unknown' to 'unknown' or something else.
