style(presence): use flat_map instead of matching Results in filter

src/api/client_server/sync.rs

@@ -537,14 +537,12 @@ async fn process_room_presence_updates(
     since: u64,
 ) -> Result<()> {
     // Take presence updates from this room
-    for presence_data in services()
+    for (user_id, _, presence_event) in services()
         .rooms
         .edus
         .presence
         .presence_since(room_id, since)
     {
-        let (user_id, _, presence_event) = presence_data?;
-
         match presence_updates.entry(user_id) {
             Entry::Vacant(slot) => {
                 slot.insert(presence_event);

src/database/key_value/rooms/edus/presence.rs

@@ -140,13 +140,13 @@ fn presence_since<'a>(
         &'a self,
         room_id: &RoomId,
         since: u64,
-    ) -> Box<dyn Iterator<Item = Result<(OwnedUserId, u64, PresenceEvent)>> + 'a> {
+    ) -> Box<dyn Iterator<Item = (OwnedUserId, u64, PresenceEvent)> + 'a> {
         let prefix = [room_id.as_bytes(), &[0xff]].concat();
 
         Box::new(
             self.roomuserid_presence
                 .scan_prefix(prefix)
-                .map(
+                .flat_map(
                     |(key, presence_bytes)| -> Result<(OwnedUserId, u64, PresenceEvent)> {
                         let user_id = user_id_from_bytes(
                             key.rsplit(|byte| *byte == 0xff).next().ok_or_else(|| {
@@ -160,10 +160,7 @@ fn presence_since<'a>(
                         Ok((user_id, presence.last_count, presence_event))
                     },
                 )
-                .filter(move |presence_data| match presence_data {
-                    Ok((_, count, _)) => *count > since,
-                    Err(_) => false,
-                }),
+                .filter(move |(_, count, _)| *count > since),
         )
     }
 }

src/service/rooms/edus/presence/data.rs

@@ -29,5 +29,5 @@ fn presence_since<'a>(
         &'a self,
         room_id: &RoomId,
         since: u64,
-    ) -> Box<dyn Iterator<Item = Result<(OwnedUserId, u64, PresenceEvent)>> + 'a>;
+    ) -> Box<dyn Iterator<Item = (OwnedUserId, u64, PresenceEvent)> + 'a>;
 }

src/service/rooms/edus/presence/mod.rs

@@ -122,11 +122,11 @@ pub fn remove_presence(&self, user_id: &UserId) -> Result<()> {
     }
 
     /// Returns the most recent presence updates that happened after the event with id `since`.
-    pub fn presence_since<'a>(
-        &'a self,
+    pub fn presence_since(
+        &self,
         room_id: &RoomId,
         since: u64,
-    ) -> Box<dyn Iterator<Item = Result<(OwnedUserId, u64, PresenceEvent)>> + 'a> {
+    ) -> Box<dyn Iterator<Item = (OwnedUserId, u64, PresenceEvent)>> {
         self.db.presence_since(room_id, since)
     }
 }

src/service/sending/mod.rs

@@ -290,14 +290,12 @@ pub fn select_edus(&self, server_name: &ServerName) -> Result<(Vec<Vec<u8>>, u64
                 // Look for presence updates in this room
                 let mut presence_updates = Vec::new();
 
-                for presence_data in services()
+                for (user_id, count, presence_event) in services()
                     .rooms
                     .edus
                     .presence
                     .presence_since(&room_id, since)
                 {
-                    let (user_id, count, presence_event) = presence_data?;
-
                     if count > max_edu_count {
                         max_edu_count = count;
                     }