Major backend refactor (#599)

Backend refactor

common/spaces/space_primitives.ts

@@ -1,21 +1,26 @@
-// export type FileEncoding = "utf8" | "arraybuffer" | "dataurl";
-// export type FileData = ArrayBuffer | string;
-
-import { FileMeta } from "$sb/types.ts";
+import type { FileMeta } from "$sb/types.ts";
 
+/**
+ * A generic interface used by `Space` to interact with the underlying storage, designed to be easy to implement for different storage backends
+ */
 export interface SpacePrimitives {
-  // Returns a list of file meta data as well as the timestamp of this snapshot
   fetchFileList(): Promise<FileMeta[]>;
+
+  // The result of this should be consistent with the result of fetchFileList for this entry
+  getFileMeta(name: string): Promise<FileMeta>;
+
   readFile(
     name: string,
   ): Promise<{ data: Uint8Array; meta: FileMeta }>;
-  getFileMeta(name: string): Promise<FileMeta>;
+
   writeFile(
     name: string,
     data: Uint8Array,
     // Used to decide whether or not to emit change events
     selfUpdate?: boolean,
+    // May be ignored, but ideally should be used to set the lastModified time
     meta?: FileMeta,
   ): Promise<FileMeta>;
+
   deleteFile(name: string): Promise<void>;
 }