feat(ui): Enable TimelineSettings::vectordiffs_as_inputs if event cache storage is enabled.

This patch automatically enables
`TimelineSettings::vectordiffs_as_inputs` if and only if the event cache
storage is enabled.

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

@@ -162,12 +162,17 @@ impl TimelineBuilder {
         )
     )]
     pub async fn build(self) -> Result<Timeline, Error> {
-        let Self { room, settings, unable_to_decrypt_hook, focus, internal_id_prefix } = self;
-        let settings_vectordiffs_as_inputs = settings.vectordiffs_as_inputs;
+        let Self { room, mut settings, unable_to_decrypt_hook, focus, internal_id_prefix } = self;
 
         let client = room.client();
         let event_cache = client.event_cache();
 
+        // Enable `TimelineSettings::vectordiffs_as_inputs` if and only if the event
+        // cache storage is enabled.
+        settings.vectordiffs_as_inputs = event_cache.has_storage();
+
+        let settings_vectordiffs_as_inputs = settings.vectordiffs_as_inputs;
+
         // Subscribe the event cache to sync responses, in case we hadn't done it yet.
         event_cache.subscribe()?;
 

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

@@ -175,6 +175,11 @@ impl EventCache {
         Ok(())
     }
 
+    /// Check whether the storage is enabled or not.
+    pub fn has_storage(&self) -> bool {
+        self.inner.has_storage()
+    }
+
     /// Starts subscribing the [`EventCache`] to sync responses, if not done
     /// before.
     ///