starknet_particia_storage: extend the storage trait to optionally flush to cache

Author: nimrod-starkware

crates/starknet_patricia_storage/src/map_storage.rs

@@ -223,10 +223,8 @@ impl<S: Storage> CachedStorage<S> {
     }
 
     pub fn flush_to_cache(&mut self, map: DbHashMap) {
-        let cache =
-            Arc::get_mut(&mut self.cache).expect("Failed to get mutable reference to cache.");
         map.into_iter().for_each(|(key, value)| {
-            cache.put(key, Some(value));
+            self.cache.put(key, Some(value));
         });
     }
 }
@@ -321,4 +319,8 @@ impl<S: Storage> Storage for CachedStorage<S> {
         // Need a concrete Option type.
         None::<NullStorage>
     }
+    fn flush_to_cache(&mut self, map: DbHashMap) -> PatriciaStorageResult<()> {
+        Self::flush_to_cache(self, map);
+        Ok(())
+    }
 }

crates/starknet_patricia_storage/src/storage_trait.rs

@@ -155,6 +155,11 @@ pub trait Storage: Send + Sync {
 
     /// If the storage is async, returns an instance of the async storage.
     fn get_async_self(&self) -> Option<impl AsyncStorage>;
+
+    /// If uses a cache, flushes the given map into the cache.
+    fn flush_to_cache(&mut self, _map: DbHashMap) -> PatriciaStorageResult<()> {
+        Ok(())
+    }
 }
 
 /// A trait wrapper for [Storage] that supports concurrency.