refactor(sdk): Remove FrozenSlidingSync.

This patch removes `FrozenSlidingSync`. Its unique field is supposed to
be stored in the crypto store.

Author: Hywan

crates/matrix-sdk/src/sliding_sync/builder.rs

@@ -246,8 +246,7 @@ impl SlidingSyncBuilder {
         }
 
         // Reload existing state from the cache.
-        let restored_fields =
-            restore_sliding_sync_state(&client, &self.storage_key, &lists).await?;
+        let restored_fields = restore_sliding_sync_state(&client, &self.storage_key).await?;
 
         let pos = if let Some(fields) = restored_fields {
             #[cfg(feature = "e2e-encryption")]

crates/matrix-sdk/src/sliding_sync/cache.rs

@@ -4,17 +4,12 @@
 //! same cache. It helps to define what it sometimes called a “cold start”, or a
 //!  “fast start”.
 
-use std::collections::BTreeMap;
-
 use matrix_sdk_base::{StateStore, StoreError};
 use matrix_sdk_common::timer;
 use ruma::UserId;
 use tracing::{trace, warn};
 
-use super::{
-    FrozenSlidingSync, FrozenSlidingSyncList, SlidingSync, SlidingSyncList,
-    SlidingSyncPositionMarkers,
-};
+use super::{FrozenSlidingSyncList, SlidingSync, SlidingSyncPositionMarkers};
 #[cfg(feature = "e2e-encryption")]
 use crate::sliding_sync::FrozenSlidingSyncPos;
 use crate::{sliding_sync::SlidingSyncListCachePolicy, Client, Result};
@@ -48,30 +43,6 @@ async fn invalidate_cached_list(
     let _ = storage.remove_custom_value(storage_key_for_list.as_bytes()).await;
 }
 
-/// Clean the storage for everything related to `SlidingSync` and all known
-/// lists.
-async fn clean_storage(
-    client: &Client,
-    storage_key: &str,
-    lists: &BTreeMap<String, SlidingSyncList>,
-) {
-    let storage = client.state_store();
-    for list_name in lists.keys() {
-        invalidate_cached_list(storage, storage_key, list_name).await;
-    }
-    let instance_storage_key = format_storage_key_for_sliding_sync(storage_key);
-    let _ = storage.remove_custom_value(instance_storage_key.as_bytes()).await;
-
-    #[cfg(feature = "e2e-encryption")]
-    if let Some(olm_machine) = &*client.olm_machine().await {
-        // Invalidate the value stored for the TERRIBLE HACK.
-        let _ = olm_machine
-            .store()
-            .set_custom_value(&instance_storage_key, "".as_bytes().to_vec())
-            .await;
-    }
-}
-
 /// Store the `SlidingSync`'s state in the storage.
 pub(super) async fn store_sliding_sync_state(
     sliding_sync: &SlidingSync,
@@ -83,15 +54,6 @@ pub(super) async fn store_sliding_sync_state(
     trace!(storage_key, "Saving a `SlidingSync` to the state store");
     let storage = sliding_sync.inner.client.state_store();
 
-    // Write this `SlidingSync` instance, as a `FrozenSlidingSync` instance, inside
-    // the store.
-    storage
-        .set_custom_value(
-            instance_storage_key.as_bytes(),
-            serde_json::to_vec(&FrozenSlidingSync::new())?,
-        )
-        .await?;
-
     #[cfg(feature = "e2e-encryption")]
     {
         let position = _position;
@@ -194,7 +156,6 @@ pub(super) struct RestoredFields {
 pub(super) async fn restore_sliding_sync_state(
     client: &Client,
     storage_key: &str,
-    lists: &BTreeMap<String, SlidingSyncList>,
 ) -> Result<Option<RestoredFields>> {
     let _timer = timer!(format!("loading sliding sync {storage_key} state from DB"));
 
@@ -210,61 +171,17 @@ pub(super) async fn restore_sliding_sync_state(
         }
     }
 
-    let storage = client.state_store();
     let instance_storage_key = format_storage_key_for_sliding_sync(storage_key);
 
     // Preload the `SlidingSync` object from the cache.
-    match storage
-        .get_custom_value(instance_storage_key.as_bytes())
-        .await?
-        .map(|custom_value| serde_json::from_slice::<FrozenSlidingSync>(&custom_value))
-    {
-        // `SlidingSync` has been found and successfully deserialized.
-        Some(Ok(FrozenSlidingSync { to_device_since })) => {
-            trace!("Successfully read the `SlidingSync` from the cache");
-            // Only update the to-device token if we failed to read it from the crypto store
-            // above.
-            if restored_fields.to_device_token.is_none() {
-                restored_fields.to_device_token = to_device_since;
-            }
-
-            #[cfg(feature = "e2e-encryption")]
-            {
-                if let Some(olm_machine) = &*client.olm_machine().await {
-                    if let Ok(Some(blob)) =
-                        olm_machine.store().get_custom_value(&instance_storage_key).await
-                    {
-                        if let Ok(frozen_pos) =
-                            serde_json::from_slice::<FrozenSlidingSyncPos>(&blob)
-                        {
-                            trace!("Successfully read the `Sliding Sync` pos from the crypto store cache");
-                            restored_fields.pos = frozen_pos.pos;
-                        }
-                    }
-                }
+    #[cfg(feature = "e2e-encryption")]
+    if let Some(olm_machine) = &*client.olm_machine().await {
+        if let Ok(Some(blob)) = olm_machine.store().get_custom_value(&instance_storage_key).await {
+            if let Ok(frozen_pos) = serde_json::from_slice::<FrozenSlidingSyncPos>(&blob) {
+                trace!("Successfully read the `Sliding Sync` pos from the crypto store cache");
+                restored_fields.pos = frozen_pos.pos;
             }
         }
-
-        // `SlidingSync` has been found, but it wasn't possible to deserialize it. It's
-        // declared as obsolete. The main reason might be that the internal
-        // representation of a `SlidingSync` might have changed.
-        // Instead of considering this as a strong error, we remove
-        // the entry from the cache and keep `SlidingSync` in its initial
-        // state.
-        Some(Err(_)) => {
-            warn!(
-                "failed to deserialize `SlidingSync` from the cache, it is obsolete; removing the cache entry!"
-            );
-
-            // Let's clear everything and stop here.
-            clean_storage(client, storage_key, lists).await;
-
-            return Ok(None);
-        }
-
-        None => {
-            trace!("No Sliding Sync object in the cache");
-        }
     }
 
     Ok(Some(restored_fields))
@@ -274,13 +191,12 @@ pub(super) async fn restore_sliding_sync_state(
 mod tests {
     use std::sync::{Arc, RwLock};
 
-    use assert_matches::assert_matches;
     use matrix_sdk_test::async_test;
 
     use super::{
-        clean_storage, format_storage_key_for_sliding_sync,
+        super::SlidingSyncList, format_storage_key_for_sliding_sync,
         format_storage_key_for_sliding_sync_list, format_storage_key_prefix,
-        restore_sliding_sync_state, store_sliding_sync_state, SlidingSyncList,
+        restore_sliding_sync_state, store_sliding_sync_state,
     };
     use crate::{test_utils::logged_in_client, Result};
 
@@ -291,30 +207,26 @@ mod tests {
 
         let store = client.state_store();
 
-        // Store entries don't exist.
-        assert!(store
-            .get_custom_value(format_storage_key_for_sliding_sync("hello").as_bytes())
-            .await?
-            .is_none());
+        let sync_id = "test-sync-id";
+        let storage_key = format_storage_key_prefix(sync_id, client.user_id().unwrap());
 
+        // Store entries don't exist.
         assert!(store
             .get_custom_value(
-                format_storage_key_for_sliding_sync_list("hello", "list_foo").as_bytes()
+                format_storage_key_for_sliding_sync_list(&storage_key, "list_foo").as_bytes()
             )
             .await?
             .is_none());
 
         assert!(store
             .get_custom_value(
-                format_storage_key_for_sliding_sync_list("hello", "list_bar").as_bytes()
+                format_storage_key_for_sliding_sync_list(&storage_key, "list_bar").as_bytes()
             )
             .await?
             .is_none());
 
         // Create a new `SlidingSync` instance, and store it.
         let storage_key = {
-            let sync_id = "test-sync-id";
-            let storage_key = format_storage_key_prefix(sync_id, client.user_id().unwrap());
             let sliding_sync = client
                 .sliding_sync(sync_id)?
                 .add_cached_list(SlidingSyncList::builder("list_foo"))
@@ -340,20 +252,15 @@ mod tests {
             storage_key
         };
 
-        // Store entries now exist for the sliding sync object and list_foo.
-        assert!(store
-            .get_custom_value(format_storage_key_for_sliding_sync(&storage_key).as_bytes())
-            .await?
-            .is_some());
-
+        // Store entries now exist for `list_foo`.
         assert!(store
             .get_custom_value(
                 format_storage_key_for_sliding_sync_list(&storage_key, "list_foo").as_bytes()
             )
             .await?
             .is_some());
 
-        // But not for list_bar.
+        // But not for `list_bar`.
         assert!(store
             .get_custom_value(
                 format_storage_key_for_sliding_sync_list(&storage_key, "list_bar").as_bytes()
@@ -362,83 +269,52 @@ mod tests {
             .is_none());
 
         // Create a new `SlidingSync`, and it should be read from the cache.
-        let storage_key = {
-            let sync_id = "test-sync-id";
-            let storage_key = format_storage_key_prefix(sync_id, client.user_id().unwrap());
-            let max_number_of_room_stream = Arc::new(RwLock::new(None));
-            let cloned_stream = max_number_of_room_stream.clone();
-            let sliding_sync = client
-                .sliding_sync(sync_id)?
-                .add_cached_list(SlidingSyncList::builder("list_foo").once_built(move |list| {
-                    // In the `once_built()` handler, nothing has been read from the cache yet.
-                    assert_eq!(list.maximum_number_of_rooms(), None);
-
-                    let mut stream = cloned_stream.write().unwrap();
-                    *stream = Some(list.maximum_number_of_rooms_stream());
-                    list
-                }))
-                .await?
-                .add_list(SlidingSyncList::builder("list_bar"))
-                .build()
-                .await?;
-
-            // Check the list' state.
-            {
-                let lists = sliding_sync.inner.lists.read().await;
-
-                // This one was cached.
-                let list_foo = lists.get("list_foo").unwrap();
-                assert_eq!(list_foo.maximum_number_of_rooms(), Some(42));
-
-                // This one wasn't.
-                let list_bar = lists.get("list_bar").unwrap();
-                assert_eq!(list_bar.maximum_number_of_rooms(), None);
-            }
-
-            // The maximum number of rooms reloaded from the cache should have been
-            // published.
-            {
-                let mut stream =
-                    max_number_of_room_stream.write().unwrap().take().expect("stream must be set");
-                let initial_max_number_of_rooms =
-                    stream.next().await.expect("stream must have emitted something");
-                assert_eq!(initial_max_number_of_rooms, Some(42));
-            }
+        let max_number_of_room_stream = Arc::new(RwLock::new(None));
+        let cloned_stream = max_number_of_room_stream.clone();
+        let sliding_sync = client
+            .sliding_sync(sync_id)?
+            .add_cached_list(SlidingSyncList::builder("list_foo").once_built(move |list| {
+                // In the `once_built()` handler, nothing has been read from the cache yet.
+                assert_eq!(list.maximum_number_of_rooms(), None);
+
+                let mut stream = cloned_stream.write().unwrap();
+                *stream = Some(list.maximum_number_of_rooms_stream());
+                list
+            }))
+            .await?
+            .add_list(SlidingSyncList::builder("list_bar"))
+            .build()
+            .await?;
 
-            // Clean the cache.
+        // Check the list' state.
+        {
             let lists = sliding_sync.inner.lists.read().await;
-            clean_storage(&client, &storage_key, &lists).await;
-            storage_key
-        };
 
-        // Store entries don't exist.
-        assert!(store
-            .get_custom_value(format_storage_key_for_sliding_sync(&storage_key).as_bytes())
-            .await?
-            .is_none());
+            // This one was cached.
+            let list_foo = lists.get("list_foo").unwrap();
+            assert_eq!(list_foo.maximum_number_of_rooms(), Some(42));
 
-        assert!(store
-            .get_custom_value(
-                format_storage_key_for_sliding_sync_list(&storage_key, "list_foo").as_bytes()
-            )
-            .await?
-            .is_none());
+            // This one wasn't.
+            let list_bar = lists.get("list_bar").unwrap();
+            assert_eq!(list_bar.maximum_number_of_rooms(), None);
+        }
 
-        assert!(store
-            .get_custom_value(
-                format_storage_key_for_sliding_sync_list(&storage_key, "list_bar").as_bytes()
-            )
-            .await?
-            .is_none());
+        // The maximum number of rooms reloaded from the cache should have been
+        // published.
+        {
+            let mut stream =
+                max_number_of_room_stream.write().unwrap().take().expect("stream must be set");
+            let initial_max_number_of_rooms =
+                stream.next().await.expect("stream must have emitted something");
+            assert_eq!(initial_max_number_of_rooms, Some(42));
+        }
 
         Ok(())
     }
 
     #[cfg(feature = "e2e-encryption")]
     #[async_test]
     async fn test_sliding_sync_high_level_cache_and_restore() -> Result<()> {
-        use crate::sliding_sync::FrozenSlidingSync;
-
         let client = logged_in_client(Some("https://foo.bar".to_owned())).await;
 
         let sync_id = "test-sync-id";
@@ -465,21 +341,10 @@ mod tests {
             store_sliding_sync_state(&sliding_sync, &position_guard).await?;
         }
 
-        // The delta token has been correctly written to the state store (but not the
-        // to_device_since, since it's in the other store).
-        let state_store = client.state_store();
-        assert_matches!(
-            state_store.get_custom_value(full_storage_key.as_bytes()).await?,
-            Some(bytes) => {
-                let deserialized: FrozenSlidingSync = serde_json::from_slice(&bytes)?;
-                assert!(deserialized.to_device_since.is_none());
-            }
-        );
-
         // Ok, forget about the sliding sync, let's recreate one from scratch.
         drop(sliding_sync);
 
-        let restored_fields = restore_sliding_sync_state(&client, &storage_key_prefix, &[].into())
+        let restored_fields = restore_sliding_sync_state(&client, &storage_key_prefix)
             .await?
             .expect("must have restored sliding sync fields");
 
@@ -496,28 +361,6 @@ mod tests {
             assert!(olm_machine.store().next_batch_token().await?.is_none());
         }
 
-        let to_device_token = "to_device_token".to_owned();
-
-        // Put that delta-token in the state store.
-        let state_store = client.state_store();
-        state_store
-            .set_custom_value(
-                full_storage_key.as_bytes(),
-                serde_json::to_vec(&FrozenSlidingSync {
-                    to_device_since: Some(to_device_token.clone()),
-                })?,
-            )
-            .await?;
-
-        let restored_fields = restore_sliding_sync_state(&client, &storage_key_prefix, &[].into())
-            .await?
-            .expect("must have restored fields");
-
-        // After restoring, the to-device since token, and the stream position could be
-        // read from the state store.
-        assert_eq!(restored_fields.to_device_token.unwrap(), to_device_token);
-        assert_eq!(restored_fields.pos.unwrap(), pos);
-
         Ok(())
     }
 }