feat(ui): Add RoomListService::new_with_share_pos.

This patch adds the new `RoomListService::new_with_share_pos`
constructor. It decides whether the `share_pos` feature of sliding sync
should be enabled or not.

`SyncServiceBuilder` gains a new `with_share_pos` method to configure
the way the `RoomListService` is built.

The FFI bindings are updated accordingly.

bindings/matrix-sdk-ffi/src/sync_service.rs

@@ -119,6 +119,12 @@ impl SyncServiceBuilder {
         Arc::new(Self { builder, ..this })
     }
 
+    pub fn with_share_pos(self: Arc<Self>, enable: bool) -> Arc<Self> {
+        let this = unwrap_or_clone_arc(self);
+        let builder = this.builder.with_share_pos(enable);
+        Arc::new(Self { builder, ..this })
+    }
+
     pub async fn finish(self: Arc<Self>) -> Result<Arc<SyncService>, ClientError> {
         let this = unwrap_or_clone_arc(self);
         Ok(Arc::new(SyncService {

crates/matrix-sdk-ui/src/room_list_service/mod.rs

@@ -131,7 +131,15 @@ impl RoomListService {
     /// to create one in this case using
     /// [`EncryptionSyncService`][crate::encryption_sync_service::EncryptionSyncService].
     pub async fn new(client: Client) -> Result<Self, Error> {
-        let builder = client
+        Self::new_with_share_pos(client, true).await
+    }
+
+    /// Like [`RoomListService::new`] but with a flag to turn the
+    /// [`SlidingSyncBuilder::share_pos`] on and off.
+    ///
+    /// [`SlidingSyncBuilder::share_pos`]: matrix_sdk::sliding_sync::SlidingSyncBuilder::share_pos
+    pub async fn new_with_share_pos(client: Client, share_pos: bool) -> Result<Self, Error> {
+        let mut builder = client
             .sliding_sync("room-list")
             .map_err(Error::SlidingSync)?
             .with_account_data_extension(
@@ -143,9 +151,12 @@ impl RoomListService {
             }))
             .with_typing_extension(assign!(http::request::Typing::default(), {
                 enabled: Some(true),
-            }))
+            }));
+
+        if share_pos {
             // We don't deal with encryption device messages here so this is safe
-            .share_pos();
+            builder = builder.share_pos();
+        }
 
         let sliding_sync = builder
             .add_cached_list(

crates/matrix-sdk-ui/src/sync_service.rs

@@ -763,6 +763,11 @@ pub struct SyncServiceBuilder {
     /// The offline mode is described in the [`State::Offline`] enum variant.
     with_offline_mode: bool,
 
+    /// Whether to turn [`SlidingSyncBuilder::share_pos`] on or off.
+    ///
+    /// [`SlidingSyncBuilder::share_pos`]: matrix_sdk::sliding_sync::SlidingSyncBuilder::share_pos
+    with_share_pos: bool,
+
     /// The parent tracing span to use for the tasks within this service.
     ///
     /// Normally this will be [`Span::none`], but it may be useful to assign a
@@ -777,6 +782,7 @@ impl SyncServiceBuilder {
             client,
             with_cross_process_lock: false,
             with_offline_mode: false,
+            with_share_pos: true,
             parent_span: Span::none(),
         }
     }
@@ -805,6 +811,14 @@ impl SyncServiceBuilder {
         self
     }
 
+    /// Whether to turn [`SlidingSyncBuilder::share_pos`] on or off.
+    ///
+    /// [`SlidingSyncBuilder::share_pos`]: matrix_sdk::sliding_sync::SlidingSyncBuilder::share_pos
+    pub fn with_share_pos(mut self, enable: bool) -> Self {
+        self.with_share_pos = enable;
+        self
+    }
+
     /// Set the parent tracing span to be used for the tasks within this
     /// service.
     pub fn with_parent_span(mut self, parent_span: Span) -> Self {
@@ -818,11 +832,17 @@ impl SyncServiceBuilder {
     /// the background. The resulting [`SyncService`] must be kept alive as long
     /// as the sliding syncs are supposed to run.
     pub async fn build(self) -> Result<SyncService, Error> {
-        let Self { client, with_cross_process_lock, with_offline_mode, parent_span } = self;
+        let Self {
+            client,
+            with_cross_process_lock,
+            with_offline_mode,
+            with_share_pos,
+            parent_span,
+        } = self;
 
         let encryption_sync_permit = Arc::new(AsyncMutex::new(EncryptionSyncPermit::new()));
 
-        let room_list = RoomListService::new(client.clone()).await?;
+        let room_list = RoomListService::new_with_share_pos(client.clone(), with_share_pos).await?;
 
         let encryption_sync = Arc::new(
             EncryptionSyncService::new(client, None, WithLocking::from(with_cross_process_lock))