프론트엔드 파일시스템 모듈 리팩토링

src/lib/modules/filesystem/internal.svelte.ts

@@ -0,0 +1,84 @@
+import { unwrapDataKey, decryptString } from "$lib/modules/crypto";
+
+export class FilesystemCache<K, V extends RV, RV = V> {
+  private map = new Map<K, V | Promise<V>>();
+
+  get(key: K, loader: (isInitial: boolean, resolve: (value: RV) => void) => void) {
+    const info = this.map.get(key);
+    if (info instanceof Promise) {
+      return info;
+    }
+
+    const { promise, resolve } = Promise.withResolvers<V>();
+    if (!info) {
+      this.map.set(key, promise);
+    }
+
+    loader(!info, (loadedInfo) => {
+      let info = this.map.get(key)!;
+      if (info instanceof Promise) {
+        const state = $state(loadedInfo);
+        this.map.set(key, state as V);
+        resolve(state as V);
+      } else {
+        Object.assign(info, loadedInfo);
+        resolve(info);
+      }
+    });
+
+    return info ?? promise;
+  }
+
+  delete(key: K) {
+    this.map.delete(key);
+  }
+}
+
+export const decryptDirectoryMetadata = async (
+  metadata: { dek: string; dekVersion: Date; name: string; nameIv: string },
+  masterKey: CryptoKey,
+) => {
+  const { dataKey } = await unwrapDataKey(metadata.dek, masterKey);
+  const name = await decryptString(metadata.name, metadata.nameIv, dataKey);
+
+  return {
+    dataKey: { key: dataKey, version: metadata.dekVersion },
+    name,
+  };
+};
+
+const decryptDate = async (ciphertext: string, iv: string, dataKey: CryptoKey) => {
+  return new Date(parseInt(await decryptString(ciphertext, iv, dataKey), 10));
+};
+
+export const decryptFileMetadata = async (
+  metadata: {
+    dek: string;
+    dekVersion: Date;
+    name: string;
+    nameIv: string;
+    createdAt?: string;
+    createdAtIv?: string;
+    lastModifiedAt: string;
+    lastModifiedAtIv: string;
+  },
+  masterKey: CryptoKey,
+) => {
+  const { dataKey } = await unwrapDataKey(metadata.dek, masterKey);
+  const [name, createdAt, lastModifiedAt] = await Promise.all([
+    decryptString(metadata.name, metadata.nameIv, dataKey),
+    metadata.createdAt
+      ? decryptDate(metadata.createdAt, metadata.createdAtIv!, dataKey)
+      : undefined,
+    decryptDate(metadata.lastModifiedAt, metadata.lastModifiedAtIv, dataKey),
+  ]);
+
+  return {
+    dataKey: { key: dataKey, version: metadata.dekVersion },
+    name,
+    createdAt,
+    lastModifiedAt,
+  };
+};
+
+export const decryptCategoryMetadata = decryptDirectoryMetadata;