sending queue: do a few renamings after the live review

Thanks @Hywan for the review comments!

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

@@ -284,8 +284,10 @@ pub(crate) struct ClientInner {
     #[cfg(feature = "e2e-encryption")]
     pub(crate) verification_state: SharedObservable<VerificationState>,
 
-    /// Data related to the sending queue.
-    pub(crate) sending_queue: Arc<SendingQueueData>,
+    /// Data related to the [`SendingQueue`].
+    ///
+    /// [`SendingQueue`]: crate::send_queue::SendingQueue
+    pub(crate) sending_queue_data: Arc<SendingQueueData>,
 }
 
 impl ClientInner {
@@ -328,7 +330,7 @@ impl ClientInner {
             respect_login_well_known,
             sync_beat: event_listener::Event::new(),
             event_cache,
-            sending_queue,
+            sending_queue_data: sending_queue,
             #[cfg(feature = "e2e-encryption")]
             e2ee: EncryptionData::new(encryption_settings),
             #[cfg(feature = "e2e-encryption")]
@@ -2108,7 +2110,7 @@ impl Client {
                 self.inner.unstable_features.get().cloned(),
                 self.inner.respect_login_well_known,
                 self.inner.event_cache.clone(),
-                self.inner.sending_queue.clone(),
+                self.inner.sending_queue_data.clone(),
                 #[cfg(feature = "e2e-encryption")]
                 self.inner.e2ee.encryption_settings,
             )

crates/matrix-sdk/src/send_queue.rs

@@ -52,7 +52,7 @@ impl SendingQueue {
     }
 
     fn for_room(&self, room: Room) -> RoomSendingQueue {
-        let data = &self.client.inner.sending_queue;
+        let data = &self.client.inner.sending_queue_data;
 
         let mut map = data.rooms.write().unwrap();
 
@@ -63,8 +63,8 @@ impl SendingQueue {
 
         let owned_room_id = room_id.to_owned();
         let room_q = RoomSendingQueue::new(
-            data.enabled.clone(),
-            data.shutting_down.clone(),
+            data.globally_enabled.clone(),
+            data.is_dropping.clone(),
             &self.client,
             owned_room_id.clone(),
         );
@@ -72,14 +72,14 @@ impl SendingQueue {
         room_q
     }
 
-    /// Enables the sending queue for the entire client, i.e. all rooms.
+    /// Enable the sending queue for the entire client, i.e. all rooms.
     ///
-    /// This may wake up backgrounds tasks and resume sending of events in the
+    /// This may wake up background tasks and resume sending of events in the
     /// background.
     pub fn enable(&self) {
-        if self.client.inner.sending_queue.enabled.set_if_not_eq(true).is_some() {
+        if self.client.inner.sending_queue_data.globally_enabled.set_if_not_eq(true).is_some() {
             debug!("globally enabling sending queue");
-            let rooms = self.client.inner.sending_queue.rooms.read().unwrap();
+            let rooms = self.client.inner.sending_queue_data.rooms.read().unwrap();
             // Wake up the rooms, in case events have been queued in the meanwhile.
             for room in rooms.values() {
                 room.inner.notifier.notify_one();
@@ -87,7 +87,7 @@ impl SendingQueue {
         }
     }
 
-    /// Disables the sending queue for the entire client, i.e. all rooms.
+    /// Disable the sending queue for the entire client, i.e. all rooms.
     ///
     /// If requests were being sent, they're not aborted, and will continue
     /// until a status resolves (error responses will keep the events in the
@@ -101,19 +101,19 @@ impl SendingQueue {
         // - or they were not, and it's not worth it waking them to let them they're
         // disabled, which causes them to go to sleep again.
         debug!("globally disabling sending queue");
-        self.client.inner.sending_queue.enabled.set(false);
+        self.client.inner.sending_queue_data.globally_enabled.set(false);
     }
 
     /// Returns whether the sending queue is enabled, at a client-wide
     /// granularity.
     pub fn is_enabled(&self) -> bool {
-        self.client.inner.sending_queue.enabled.get()
+        self.client.inner.sending_queue_data.globally_enabled.get()
     }
 
     /// A subscriber to the enablement status (enabled or disabled) of the
     /// sending queue.
     pub fn subscribe_status(&self) -> Subscriber<bool> {
-        self.client.inner.sending_queue.enabled.subscribe()
+        self.client.inner.sending_queue_data.globally_enabled.subscribe()
     }
 }
 
@@ -130,19 +130,19 @@ pub(super) struct SendingQueueData {
     rooms: SyncRwLock<BTreeMap<OwnedRoomId, RoomSendingQueue>>,
 
     /// Is the whole mechanism enabled or disabled?
-    enabled: SharedObservable<bool>,
+    globally_enabled: SharedObservable<bool>,
 
-    /// Are we shutting down the entire queue?
-    shutting_down: Arc<AtomicBool>,
+    /// Are we currently dropping the Client?
+    is_dropping: Arc<AtomicBool>,
 }
 
 impl SendingQueueData {
     /// Create the data for a sending queue, in the given enabled state.
-    pub fn new(enabled: bool) -> Self {
+    pub fn new(globally_enabled: bool) -> Self {
         Self {
             rooms: Default::default(),
-            enabled: SharedObservable::new(enabled),
-            shutting_down: Arc::new(false.into()),
+            globally_enabled: SharedObservable::new(globally_enabled),
+            is_dropping: Arc::new(false.into()),
         }
     }
 }
@@ -151,8 +151,8 @@ impl Drop for SendingQueueData {
     fn drop(&mut self) {
         // Mark the whole sending queue as shutting down, then wake up all the room
         // queues so they're stopped too.
-        debug!("globally shutting down the sending queue");
-        self.shutting_down.store(true, Ordering::SeqCst);
+        debug!("globally dropping the sending queue");
+        self.is_dropping.store(true, Ordering::SeqCst);
 
         let rooms = self.rooms.read().unwrap();
         for room in rooms.values() {
@@ -184,14 +184,14 @@ impl std::fmt::Debug for RoomSendingQueue {
 
 impl RoomSendingQueue {
     fn new(
-        enabled: SharedObservable<bool>,
-        shutting_down: Arc<AtomicBool>,
+        globally_enabled: SharedObservable<bool>,
+        is_dropping: Arc<AtomicBool>,
         client: &Client,
         room_id: OwnedRoomId,
     ) -> Self {
         let (updates_sender, _) = broadcast::channel(32);
 
-        let queue = SharedQueue::new();
+        let queue = QueueStorage::new();
         let notifier = Arc::new(Notify::new());
 
         let weak_room = WeakRoom::new(WeakClient::from_client(client), room_id);
@@ -201,8 +201,8 @@ impl RoomSendingQueue {
             queue.clone(),
             notifier.clone(),
             updates_sender.clone(),
-            enabled,
-            shutting_down,
+            globally_enabled,
+            is_dropping,
         ));
 
         Self {
@@ -242,6 +242,7 @@ impl RoomSendingQueue {
 
         let transaction_id = self.inner.queue.push(content.clone()).await;
         trace!(%transaction_id, "manager sends an event to the background task");
+
         self.inner.notifier.notify_one();
 
         let _ = self.inner.updates.send(RoomSendingQueueUpdate::NewLocalEvent(LocalEcho {
@@ -261,29 +262,29 @@ impl RoomSendingQueue {
     #[instrument(skip_all, fields(room_id = %room.room_id()))]
     async fn sending_task(
         room: WeakRoom,
-        queue: SharedQueue,
+        queue: QueueStorage,
         notifier: Arc<Notify>,
         updates: broadcast::Sender<RoomSendingQueueUpdate>,
-        enabled: SharedObservable<bool>,
-        shutting_down: Arc<AtomicBool>,
+        globally_enabled: SharedObservable<bool>,
+        is_dropping: Arc<AtomicBool>,
     ) {
         info!("spawned the sending task");
 
         loop {
             // A request to shut down should be preferred above everything else.
-            if shutting_down.load(Ordering::SeqCst) {
+            if is_dropping.load(Ordering::SeqCst) {
                 trace!("shutting down!");
                 break;
             }
 
-            if !enabled.get() {
+            if !globally_enabled.get() {
                 trace!("not enabled, sleeping");
                 // Wait for an explicit wakeup.
                 notifier.notified().await;
                 continue;
             }
 
-            let Some(queued_event) = queue.pop_next_to_send().await else {
+            let Some(queued_event) = queue.peek_next_to_send().await else {
                 trace!("queue is empty, sleeping");
                 // Wait for an explicit wakeup.
                 notifier.notified().await;
@@ -293,7 +294,7 @@ impl RoomSendingQueue {
             trace!("received an event to send!");
 
             let Some(room) = room.get() else {
-                if shutting_down.load(Ordering::SeqCst) {
+                if is_dropping.load(Ordering::SeqCst) {
                     break;
                 }
                 error!("the weak room couldn't be upgraded but we're not shutting down?");
@@ -322,7 +323,7 @@ impl RoomSendingQueue {
 
                     // Disable the queue after an error.
                     // See comment in [`SendingQueue::disable()`].
-                    enabled.set(false);
+                    globally_enabled.set(false);
 
                     // In this case, we intentionally keep the event in the queue, but mark it as
                     // not being sent anymore.
@@ -360,10 +361,10 @@ struct RoomSendingQueueInner {
     /// content / deleting entries, all that will be required will be to
     /// manipulate the on-disk storage. In other words, the storage will become
     /// the one source of truth.
-    queue: SharedQueue,
+    queue: QueueStorage,
 
     /// A notifier that's updated any time common data is touched (stopped or
-    /// enabled statuses), or the associated room [`SharedQueue`].
+    /// enabled statuses), or the associated room [`QueueStorage`].
     notifier: Arc<Notify>,
 
     /// Handle to the actual sending task. Unused, but kept alive along this
@@ -375,13 +376,18 @@ struct RoomSendingQueueInner {
 struct QueuedEvent {
     event: AnyMessageLikeEventContent,
     transaction_id: OwnedTransactionId,
+
+    /// Flag to indicate if an event has been scheduled for sending.
+    ///
+    /// Useful to indicate if cancelling could happen or if it was too late and
+    /// the event had already been sent.
     is_being_sent: bool,
 }
 
 #[derive(Clone)]
-struct SharedQueue(Arc<RwLock<VecDeque<QueuedEvent>>>);
+struct QueueStorage(Arc<RwLock<VecDeque<QueuedEvent>>>);
 
-impl SharedQueue {
+impl QueueStorage {
     /// Create a new synchronized queue for queuing events to be sent later.
     fn new() -> Self {
         Self(Arc::new(RwLock::new(VecDeque::with_capacity(16))))
@@ -402,13 +408,15 @@ impl SharedQueue {
         transaction_id
     }
 
-    /// Pops the next event to be sent, marking it as being sent.
+    /// Peeks the next event to be sent, marking it as being sent.
     ///
     /// It is required to call [`Self::mark_as_sent`] after it's been
     /// effectively sent.
-    async fn pop_next_to_send(&self) -> Option<QueuedEvent> {
+    async fn peek_next_to_send(&self) -> Option<QueuedEvent> {
         let mut q = self.0.write().await;
         if let Some(event) = q.front_mut() {
+            // TODO: This flag should probably live in memory when we have an actual
+            // storage.
             event.is_being_sent = true;
             Some(event.clone())
         } else {
@@ -416,7 +424,7 @@ impl SharedQueue {
         }
     }
 
-    /// Marks an event popped with [`Self::pop_next_to_send`] and identified
+    /// Marks an event popped with [`Self::peek_next_to_send`] and identified
     /// with the given transaction id as not being sent anymore, so it can
     /// be removed from the queue later.
     async fn mark_as_not_being_sent(&self, transaction_id: &TransactionId) {
@@ -432,7 +440,11 @@ impl SharedQueue {
     /// transaction id as sent by removing it from the local queue.
     async fn mark_as_sent(&self, transaction_id: &TransactionId) {
         let mut q = self.0.write().await;
-        q.retain(|item| item.transaction_id != transaction_id);
+        if let Some(index) = q.iter().position(|item| item.transaction_id == transaction_id) {
+            q.remove(index);
+        } else {
+            warn!("couldn't find item to mark as sent with transaction id {transaction_id}");
+        }
     }
 
     /// Cancel a sending command for an event that has been sent with