For some room lists, the number of entries can be gigantic. For example,
some accounts have 800, 2500, or even 4000 rooms! It's not necessary for
the client/app to display all the 4000 rooms. First, it can create some
performance issues, second, nobody will scroll 4000 rooms to search for
a particular room :-). Such users are more likely to use a search bar or
something equivalent. The idea is that `RoomListService` will continue
to sync all the data, but only a _limited_ version of it will be shared
to the client/app.
This patch takes `RoomList::entries_with_dynamic_filter`, and improves
it to include this (dynamic) limit.
This patch renames `RoomList::entries_with_dynamic_filter`
to `::entries_with_dynamic_adapters`. It now returns a
`RoomListDynamicEntriesController`, which is a renaming of
`DynamicRoomListFilter`. Basically, the “dynamic filter” becomes a
“dynamic controller” because `RoomList::entries_with_dynamic_adapters`
manages more than a filter. It now uses
`eyeball_im_util::vector::DynamicLimit` to dynamically limit the size
of entries. And that's the major idea behind this patch.
`RoomListDynamicEntriesController::set` is renamed `::set_filter`, and 2
new methods are introduced: `add_one_page` and `reset_to_one_page`.
A _page_ is like a chunk of room entries we want to view or add. When
doing `next_page`, the limit increases to `old_limit + page_size`. The
`reset_pages` method resets the `limit` to `page_size` only.
Based on https://github.com/ruma/ruma/pull/1607, this patch adds
support for `avatar` from a sliding sync response. This patch implements
`SlidingSyncRoom::avatar_url` to get the avatar URL of a sliding sync
room.
This patch brings a nice code simplification.
Instead of creating a new `Stream` with `tokio` based on
`Subscriber<State>`` to drain the batch subscriber for
`RoomList::entries` and `::filtered_entries`, we can _simply_ use
`Subscriber<State>` directly! It removes one dependency: `tokio-
stream`, and remove possible issues with the broadcast channel
`tokio::sync::broadcast`. The code is much simpler and straighforward.
This patch uses a newly implemented `async-rx` crate, that provides
`StreamExt`. This trait provides new features on `Stream`, like
`StreamExt::batch_with` which allows to batch values generated by a
`Stream` into a `Vec<Stream::Item>`. The batch is drained based on
another `Stream`: every time a value is produced, it drains the batch
stream.
This feature is used in `RoomList::entries` and
`RoomList::entries_filtered` to batch `Stream<Item = VectorDiff<_>>`
into `Stream<Item = Vec<VectorDiff<_>>>`.
The “drainer” is a broadcast sender, which sends an (empty) value every
time the room list service state changes, so every time something
happens during a sync. Note that it even drains when the room list
service state jumps to `Error` or `Terminated`.
