feat: Allow Timelines to be configured for renderer that can't show read receipts on state events.

Author: pixlwave

bindings/matrix-sdk-ffi/src/room/mod.rs

@@ -233,7 +233,8 @@ impl Room {
 
         builder = builder
             .with_focus(configuration.focus.try_into()?)
-            .with_date_divider_mode(configuration.date_divider_mode.into());
+            .with_date_divider_mode(configuration.date_divider_mode.into())
+            .state_events_can_show_read_receipts(configuration.state_events_can_show_read_receipts);
 
         if configuration.track_read_receipts {
             builder = builder.track_read_marker_and_receipts();

bindings/matrix-sdk-ffi/src/timeline/configuration.rs

@@ -164,6 +164,9 @@ pub struct TimelineConfiguration {
     /// How should we filter out events from the timeline?
     pub filter: TimelineFilter,
 
+    /// Can read receipts be shown on state events or only on messages?
+    pub state_events_can_show_read_receipts: bool,
+
     /// An optional String that will be prepended to
     /// all the timeline item's internal IDs, making it possible to
     /// distinguish different timeline instances from each other.

crates/matrix-sdk-ui/src/timeline/builder.rs

@@ -141,6 +141,11 @@ impl TimelineBuilder {
         self
     }
 
+    pub fn state_events_can_show_read_receipts(mut self, show: bool) -> Self {
+        self.settings.state_events_can_show_read_receipts = show;
+        self
+    }
+
     /// Whether to add events that failed to deserialize to the timeline.
     ///
     /// Defaults to `true`.

crates/matrix-sdk-ui/src/timeline/controller/metadata.rs

@@ -519,6 +519,9 @@ pub(in crate::timeline) struct EventMeta {
     /// Whether the event is among the timeline items.
     pub visible: bool,
 
+    /// Whether the event can show read receipts.
+    pub can_show_read_receipts: bool,
+
     /// Foundation for the mapping between remote events to timeline items.
     ///
     /// Let's explain it. The events represent the first set and are stored in
@@ -587,8 +590,15 @@ impl EventMeta {
     pub fn new(
         event_id: OwnedEventId,
         visible: bool,
+        can_show_read_receipts: bool,
         thread_root_id: Option<OwnedEventId>,
     ) -> Self {
-        Self { event_id, thread_root_id, visible, timeline_item_index: None }
+        Self {
+            event_id,
+            thread_root_id,
+            visible,
+            can_show_read_receipts,
+            timeline_item_index: None,
+        }
     }
 }

crates/matrix-sdk-ui/src/timeline/controller/mod.rs

@@ -268,6 +268,9 @@ pub(super) struct TimelineSettings {
     /// Should the read receipts and read markers be handled?
     pub(super) track_read_receipts: bool,
 
+    /// Whether state events can show read receipts.
+    pub(super) state_events_can_show_read_receipts: bool,
+
     /// Event filter that controls what's rendered as a timeline item (and thus
     /// what can carry read receipts).
     pub(super) event_filter: Arc<TimelineEventFilterFn>,
@@ -284,6 +287,7 @@ impl fmt::Debug for TimelineSettings {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         f.debug_struct("TimelineSettings")
             .field("track_read_receipts", &self.track_read_receipts)
+            .field("state_events_can_show_read_receipts", &self.state_events_can_show_read_receipts)
             .field("add_failed_to_parse", &self.add_failed_to_parse)
             .finish_non_exhaustive()
     }
@@ -293,6 +297,7 @@ impl Default for TimelineSettings {
     fn default() -> Self {
         Self {
             track_read_receipts: false,
+            state_events_can_show_read_receipts: true,
             event_filter: Arc::new(default_event_filter),
             add_failed_to_parse: true,
             date_divider_mode: DateDividerMode::Daily,

crates/matrix-sdk-ui/src/timeline/controller/observable_items.rs

@@ -801,6 +801,7 @@ mod observable_items_tests {
             thread_root_id: None,
             timeline_item_index: None,
             visible: false,
+            can_show_read_receipts: false,
         }
     }
 
@@ -2065,6 +2066,7 @@ mod all_remote_events_tests {
             thread_root_id: None,
             timeline_item_index,
             visible: false,
+            can_show_read_receipts: false,
         }
     }
 

crates/matrix-sdk-ui/src/timeline/controller/read_receipts.rs

@@ -131,8 +131,13 @@ impl ReadReceipts {
                 old_receipt_pos = Some(pos);
             }
 
-            // The receipt should appear on the first event that is visible.
-            if old_receipt_pos.is_some() && old_item_event_id.is_none() && event.visible {
+            // The receipt should appear on the first visible event that can show read
+            // receipts.
+            if old_receipt_pos.is_some()
+                && old_item_event_id.is_none()
+                && event.visible
+                && event.can_show_read_receipts
+            {
                 old_item_pos = event.timeline_item_index;
                 old_item_event_id = Some(event.event_id.clone());
             }
@@ -141,8 +146,13 @@ impl ReadReceipts {
                 new_receipt_pos = Some(pos);
             }
 
-            // The receipt should appear on the first event that is visible.
-            if new_receipt_pos.is_some() && new_item_event_id.is_none() && event.visible {
+            // The receipt should appear on the first visible event that can show read
+            // receipts.
+            if new_receipt_pos.is_some()
+                && new_item_event_id.is_none()
+                && event.visible
+                && event.can_show_read_receipts
+            {
                 new_item_pos = event.timeline_item_index;
                 new_item_event_id = Some(event.event_id.clone());
             }
@@ -316,11 +326,16 @@ impl ReadReceipts {
             }
         }
 
-        // Include receipts for all the following non-visible events.
+        // Include receipts from all the following events that are hidden or can't show
+        // read receipts.
         let mut hidden = Vec::new();
-        for hidden_event_meta in events_iter.take_while(|meta| !meta.visible) {
-            if let Some(event_receipts) = self.get_event_receipts(&hidden_event_meta.event_id) {
-                trace!(%hidden_event_meta.event_id, "found receipts on hidden event");
+        for hidden_receipt_event_meta in
+            events_iter.take_while(|meta| !meta.visible || !meta.can_show_read_receipts)
+        {
+            if let Some(event_receipts) =
+                self.get_event_receipts(&hidden_receipt_event_meta.event_id)
+            {
+                trace!(%hidden_receipt_event_meta.event_id, "found receipts on hidden event");
                 hidden.extend(event_receipts.clone());
             }
         }
@@ -659,8 +674,8 @@ impl<P: RoomDataProvider> TimelineStateTransaction<'_, P> {
             .skip_while(|meta| meta.event_id != event_id)
             // Go past the event item.
             .skip(1)
-            // Find the first visible item.
-            .find(|meta| meta.visible)
+            // Find the first visible item that can show read receipts.
+            .find(|meta| meta.visible && meta.can_show_read_receipts)
         else {
             trace!("Couldn't find any previous visible event, exiting");
             return;
@@ -806,7 +821,7 @@ impl<P: RoomDataProvider> TimelineState<P> {
             .iter()
             .rev()
             .skip_while(|ev| ev.event_id != *latest_receipt_id)
-            .find(|ev| ev.visible)
+            .find(|ev| ev.visible && ev.can_show_read_receipts)
             .map(|ev| ev.event_id.clone())
     }
 }

crates/matrix-sdk-ui/src/timeline/controller/state_transaction.rs

@@ -184,7 +184,7 @@ impl<'a, P: RoomDataProvider> TimelineStateTransaction<'a, P> {
         }
 
         self.adjust_date_dividers(date_divider_adjuster);
-        self.check_invariants();
+        self.check_invariants(settings);
     }
 
     async fn handle_remote_aggregation(
@@ -339,11 +339,13 @@ impl<'a, P: RoomDataProvider> TimelineStateTransaction<'a, P> {
         }
 
         self.adjust_date_dividers(date_divider_adjuster);
-        self.check_invariants();
+        self.check_invariants(settings);
     }
 
-    fn check_invariants(&self) {
-        self.check_no_duplicate_read_receipts();
+    fn check_invariants(&self, settings: &TimelineSettings) {
+        if settings.state_events_can_show_read_receipts {
+            self.check_no_duplicate_read_receipts();
+        }
         self.check_no_unused_unique_ids();
     }
 
@@ -460,6 +462,19 @@ impl<'a, P: RoomDataProvider> TimelineStateTransaction<'a, P> {
         }
     }
 
+    /// Whether this event can show read receipts, or if they should be moved
+    /// to the previous event.
+    fn can_show_read_receipts(
+        &self,
+        settings: &TimelineSettings,
+        event: &AnySyncTimelineEvent,
+    ) -> bool {
+        match event {
+            AnySyncTimelineEvent::State(_) => settings.state_events_can_show_read_receipts,
+            AnySyncTimelineEvent::MessageLike(_) => true,
+        }
+    }
+
     /// After a deserialization error, adds a failed-to-parse item to the
     /// timeline if configured to do so, or logs the error (and optionally
     /// save metadata) if not.
@@ -478,6 +493,7 @@ impl<'a, P: RoomDataProvider> TimelineStateTransaction<'a, P> {
         Option<TimelineAction>,
         Option<OwnedEventId>,
         bool,
+        bool,
     )> {
         let state_key: Option<String> = raw.get_field("state_key").ok().flatten();
 
@@ -537,6 +553,7 @@ impl<'a, P: RoomDataProvider> TimelineStateTransaction<'a, P> {
                     Some(TimelineAction::failed_to_parse(event_type, deserialization_error)),
                     None,
                     true,
+                    true,
                 ))
             }
 
@@ -552,7 +569,7 @@ impl<'a, P: RoomDataProvider> TimelineStateTransaction<'a, P> {
                 // Remember the event before returning prematurely.
                 // See [`ObservableItems::all_remote_events`].
                 self.add_or_update_remote_event(
-                    EventMeta::new(event_id, false, None),
+                    EventMeta::new(event_id, false, false, None),
                     sender.as_deref(),
                     origin_server_ts,
                     position,
@@ -630,65 +647,74 @@ impl<'a, P: RoomDataProvider> TimelineStateTransaction<'a, P> {
             _ => (event.kind.into_raw(), None),
         };
 
-        let (event_id, sender, timestamp, txn_id, timeline_action, thread_root, should_add) =
-            match raw.deserialize() {
-                // Classical path: the event is valid, can be deserialized, everything is alright.
-                Ok(event) => {
-                    let (in_reply_to, thread_root) = self.meta.process_event_relations(
-                        &event,
-                        &raw,
-                        bundled_edit_encryption_info,
-                        &self.items,
-                        self.focus.is_thread(),
-                    );
+        let (
+            event_id,
+            sender,
+            timestamp,
+            txn_id,
+            timeline_action,
+            thread_root,
+            should_add,
+            can_show_read_receipts,
+        ) = match raw.deserialize() {
+            // Classical path: the event is valid, can be deserialized, everything is alright.
+            Ok(event) => {
+                let (in_reply_to, thread_root) = self.meta.process_event_relations(
+                    &event,
+                    &raw,
+                    bundled_edit_encryption_info,
+                    &self.items,
+                    self.focus.is_thread(),
+                );
+
+                let should_add = self.should_add_event_item(
+                    room_data_provider,
+                    settings,
+                    &event,
+                    thread_root.as_deref(),
+                    position,
+                );
+
+                let can_show_read_receipts = self.can_show_read_receipts(settings, &event);
 
-                    let should_add = self.should_add_event_item(
+                (
+                    event.event_id().to_owned(),
+                    event.sender().to_owned(),
+                    event.origin_server_ts(),
+                    event.transaction_id().map(ToOwned::to_owned),
+                    TimelineAction::from_event(
+                        event,
+                        &raw,
                         room_data_provider,
-                        settings,
-                        &event,
-                        thread_root.as_deref(),
-                        position,
-                    );
-
-                    (
-                        event.event_id().to_owned(),
-                        event.sender().to_owned(),
-                        event.origin_server_ts(),
-                        event.transaction_id().map(ToOwned::to_owned),
-                        TimelineAction::from_event(
-                            event,
-                            &raw,
-                            room_data_provider,
-                            utd_info.map(|utd_info| {
-                                (utd_info, self.meta.unable_to_decrypt_hook.as_ref())
-                            }),
-                            in_reply_to,
-                            thread_root.clone(),
-                            thread_summary,
-                        )
-                        .await,
-                        thread_root,
-                        should_add,
+                        utd_info
+                            .map(|utd_info| (utd_info, self.meta.unable_to_decrypt_hook.as_ref())),
+                        in_reply_to,
+                        thread_root.clone(),
+                        thread_summary,
                     )
-                }
+                    .await,
+                    thread_root,
+                    should_add,
+                    can_show_read_receipts,
+                )
+            }
 
-                // The event seems invalid…
-                Err(e) => {
-                    if let Some(tuple) = self
-                        .maybe_add_error_item(position, room_data_provider, &raw, e, settings)
-                        .await
-                    {
-                        tuple
-                    } else {
-                        return false;
-                    }
+            // The event seems invalid…
+            Err(e) => {
+                if let Some(tuple) =
+                    self.maybe_add_error_item(position, room_data_provider, &raw, e, settings).await
+                {
+                    tuple
+                } else {
+                    return false;
                 }
-            };
+            }
+        };
 
         // Remember the event.
         // See [`ObservableItems::all_remote_events`].
         self.add_or_update_remote_event(
-            EventMeta::new(event_id.clone(), should_add, thread_root),
+            EventMeta::new(event_id.clone(), should_add, can_show_read_receipts, thread_root),
             Some(&sender),
             Some(timestamp),
             position,
@@ -887,9 +913,11 @@ impl<'a, P: RoomDataProvider> TimelineStateTransaction<'a, P> {
             TimelineItemPosition::UpdateAt { .. } => {
                 if let Some(event) =
                     self.items.get_remote_event_by_event_id_mut(&event_meta.event_id)
-                    && event.visible != event_meta.visible
+                    && (event.visible != event_meta.visible
+                        || event.can_show_read_receipts != event_meta.can_show_read_receipts)
                 {
                     event.visible = event_meta.visible;
+                    event.can_show_read_receipts = event_meta.can_show_read_receipts;
 
                     if settings.track_read_receipts {
                         // Since the event's visibility changed, we need to update the read

crates/matrix-sdk-ui/src/timeline/tests/basic.rs

@@ -98,7 +98,11 @@ async fn test_replace_with_initial_events_and_read_marker() {
                 .with_fully_read_marker(event_id)
                 .with_initial_user_receipts(receipts),
         )
-        .settings(TimelineSettings { track_read_receipts: true, ..Default::default() })
+        .settings(TimelineSettings {
+            track_read_receipts: true,
+            state_events_can_show_read_receipts: true,
+            ..Default::default()
+        })
         .build();
 
     let f = &timeline.factory;