EventIndex: Check if a newly encrypted room is indexed before adding a checkpoint.

src/indexing/BaseEventIndexManager.ts

@@ -134,6 +134,19 @@ export default abstract class BaseEventIndexManager {
         throw new Error("Unimplemented");
     }
 
+    /**
+     * Check if the room with the given id is already indexed.
+     *
+     * @param {string} roomId The ID of the room which we want to check if it
+     * has been already indexed.
+     *
+     * @return {Promise<boolean>} Returns true if the index contains events for
+     * the given room, false otherwise.
+     */
+    isRoomIndexed(roomId: string): Promise<boolean> {
+        throw new Error("Unimplemented");
+    }
+
     /**
      * Get statistical information of the index.
      *