base: cache the computed display name and reuse that in the search filters

benchmarks/benches/room_bench.rs

@@ -63,6 +63,7 @@ pub fn receive_all_members_benchmark(c: &mut Criterion) {
         .expect("initial filling of sqlite failed");
 
     let base_client = BaseClient::with_store_config(StoreConfig::new().state_store(sqlite_store));
+
     runtime
         .block_on(base_client.set_session_meta(
             SessionMeta {
@@ -72,6 +73,7 @@ pub fn receive_all_members_benchmark(c: &mut Criterion) {
             None,
         ))
         .expect("Could not set session meta");
+
     base_client.get_or_create_room(&room_id, RoomState::Joined);
 
     let request = get_member_events::v3::Request::new(room_id.clone());

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

@@ -81,8 +81,8 @@ impl Room {
     /// Returns the room's name from the state event if available, otherwise
     /// compute a room name based on the room's nature (DM or not) and number of
     /// members.
-    pub fn display_name(&self) -> Result<String, ClientError> {
-        Ok(RUNTIME.block_on(self.inner.computed_display_name())?.to_string())
+    pub fn display_name(&self) -> Option<String> {
+        Some(self.inner.cached_display_name()?.to_string())
     }
 
     /// The raw name as present in the room state event.

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

@@ -69,7 +69,7 @@ impl RoomInfo {
 
         Ok(Self {
             id: room.room_id().to_string(),
-            display_name: room.computed_display_name().await.ok().map(|name| name.to_string()),
+            display_name: room.cached_display_name().map(|name| name.to_string()),
             raw_name: room.name(),
             topic: room.topic(),
             avatar_url: room.avatar_url().map(Into::into),

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

@@ -489,7 +489,7 @@ impl RoomListItem {
     /// compute a room name based on the room's nature (DM or not) and number of
     /// members.
     fn display_name(&self) -> Option<String> {
-        RUNTIME.block_on(self.inner.computed_display_name())
+        self.inner.cached_display_name()
     }
 
     fn avatar_url(&self) -> Option<String> {

crates/matrix-sdk-base/src/client.rs

@@ -751,6 +751,7 @@ impl BaseClient {
             RoomState::Joined,
             self.roominfo_update_sender.clone(),
         );
+
         if room.state() != RoomState::Joined {
             let _sync_lock = self.sync_lock().lock().await;
 
@@ -777,6 +778,7 @@ impl BaseClient {
             RoomState::Left,
             self.roominfo_update_sender.clone(),
         );
+
         if room.state() != RoomState::Left {
             let _sync_lock = self.sync_lock().lock().await;
 
@@ -852,6 +854,7 @@ impl BaseClient {
                 RoomState::Joined,
                 self.roominfo_update_sender.clone(),
             );
+
             let mut room_info = room.clone_info();
 
             room_info.mark_as_joined();
@@ -964,6 +967,7 @@ impl BaseClient {
                 RoomState::Left,
                 self.roominfo_update_sender.clone(),
             );
+
             let mut room_info = room.clone_info();
             room_info.mark_as_left();
             room_info.mark_state_partially_synced();
@@ -1022,6 +1026,7 @@ impl BaseClient {
                 RoomState::Invited,
                 self.roominfo_update_sender.clone(),
             );
+
             let mut room_info = room.clone_info();
             room_info.mark_as_invited();
             room_info.mark_state_fully_synced();
@@ -1066,6 +1071,13 @@ impl BaseClient {
             self.apply_changes(&changes, false);
         }
 
+        // Now that all the rooms information have been saved, update the display name
+        // cache (which relies on information stored in the database). This will
+        // live in memory, until the next sync which will saves the room info to
+        // disk; we do this to avoid saving that would be redundant with the
+        // above. Oh well.
+        new_rooms.update_in_memory_caches(&self.store).await;
+
         info!("Processed a sync response in {:?}", now.elapsed());
 
         let response = SyncResponse {
@@ -1655,7 +1667,7 @@ mod tests {
         let room = client.get_room(room_id).expect("Room not found");
         assert_eq!(room.state(), RoomState::Invited);
         assert_eq!(
-            room.computed_display_name().await.expect("fetching display name failed"),
+            room.compute_display_name().await.expect("fetching display name failed"),
             DisplayName::Calculated("Kyra".to_owned())
         );
     }

crates/matrix-sdk-base/src/rooms/mod.rs

@@ -122,15 +122,6 @@ impl BaseRoomInfo {
         Self::default()
     }
 
-    pub(crate) fn calculate_room_name(
-        &self,
-        joined_member_count: u64,
-        invited_member_count: u64,
-        heroes: Vec<&str>,
-    ) -> DisplayName {
-        calculate_room_name(joined_member_count, invited_member_count, heroes)
-    }
-
     /// Get the room version of this room.
     ///
     /// For room versions earlier than room version 11, if the event is
@@ -359,45 +350,6 @@ impl Default for BaseRoomInfo {
     }
 }
 
-/// Calculate room name according to step 3 of the [naming algorithm.]
-///
-/// [naming algorithm]: https://spec.matrix.org/latest/client-server-api/#calculating-the-display-name-for-a-room
-fn calculate_room_name(
-    joined_member_count: u64,
-    invited_member_count: u64,
-    mut heroes: Vec<&str>,
-) -> DisplayName {
-    let num_heroes = heroes.len() as u64;
-    let invited_joined = invited_member_count + joined_member_count;
-    let invited_joined_minus_one = invited_joined.saturating_sub(1);
-
-    // Stabilize ordering.
-    heroes.sort_unstable();
-
-    let names = if num_heroes == 0 && invited_joined > 1 {
-        format!("{} people", invited_joined)
-    } else if num_heroes >= invited_joined_minus_one {
-        heroes.join(", ")
-    } else if num_heroes < invited_joined_minus_one && invited_joined > 1 {
-        // TODO: What length does the spec want us to use here and in
-        // the `else`?
-        format!("{}, and {} others", heroes.join(", "), (invited_joined - num_heroes))
-    } else {
-        "".to_owned()
-    };
-
-    // User is alone.
-    if invited_joined <= 1 {
-        if names.is_empty() {
-            DisplayName::Empty
-        } else {
-            DisplayName::EmptyWas(names)
-        }
-    } else {
-        DisplayName::Calculated(names)
-    }
-}
-
 /// The content of an `m.room.create` event, with a required `creator` field.
 ///
 /// Starting with room version 11, the `creator` field should be removed and the
@@ -563,43 +515,7 @@ mod tests {
 
     use ruma::events::tag::{TagInfo, TagName, Tags};
 
-    use super::{calculate_room_name, BaseRoomInfo, DisplayName, RoomNotableTags};
-
-    #[test]
-    fn test_calculate_room_name() {
-        let mut actual = calculate_room_name(2, 0, vec!["a"]);
-        assert_eq!(DisplayName::Calculated("a".to_owned()), actual);
-
-        actual = calculate_room_name(3, 0, vec!["a", "b"]);
-        assert_eq!(DisplayName::Calculated("a, b".to_owned()), actual);
-
-        actual = calculate_room_name(4, 0, vec!["a", "b", "c"]);
-        assert_eq!(DisplayName::Calculated("a, b, c".to_owned()), actual);
-
-        actual = calculate_room_name(5, 0, vec!["a", "b", "c"]);
-        assert_eq!(DisplayName::Calculated("a, b, c, and 2 others".to_owned()), actual);
-
-        actual = calculate_room_name(5, 0, vec![]);
-        assert_eq!(DisplayName::Calculated("5 people".to_owned()), actual);
-
-        actual = calculate_room_name(0, 0, vec![]);
-        assert_eq!(DisplayName::Empty, actual);
-
-        actual = calculate_room_name(1, 0, vec![]);
-        assert_eq!(DisplayName::Empty, actual);
-
-        actual = calculate_room_name(0, 1, vec![]);
-        assert_eq!(DisplayName::Empty, actual);
-
-        actual = calculate_room_name(1, 0, vec!["a"]);
-        assert_eq!(DisplayName::EmptyWas("a".to_owned()), actual);
-
-        actual = calculate_room_name(1, 0, vec!["a", "b"]);
-        assert_eq!(DisplayName::EmptyWas("a, b".to_owned()), actual);
-
-        actual = calculate_room_name(1, 0, vec!["a", "b", "c"]);
-        assert_eq!(DisplayName::EmptyWas("a, b, c".to_owned()), actual);
-    }
+    use super::{BaseRoomInfo, RoomNotableTags};
 
     #[test]
     fn test_handle_notable_tags_favourite() {