파일 썸네일이 캐시되는 OPFS의 경로 변경

src/lib/modules/file/cache.ts

@@ -1,12 +1,15 @@
+import { LRUCache } from "lru-cache";
 import {
   getFileCacheIndex as getFileCacheIndexFromIndexedDB,
   storeFileCacheIndex,
   deleteFileCacheIndex,
   type FileCacheIndex,
 } from "$lib/indexedDB";
-import { readFile, writeFile, deleteFile } from "$lib/modules/opfs";
+import { readFile, writeFile, deleteFile, deleteDirectory } from "$lib/modules/opfs";
+import { getThumbnailUrl } from "$lib/modules/thumbnail";
 
 const fileCacheIndex = new Map<number, FileCacheIndex>();
+const loadedThumbnails = new LRUCache<number, string>({ max: 100 });
 
 export const prepareFileCache = async () => {
   for (const cache of await getFileCacheIndexFromIndexedDB()) {
@@ -48,3 +51,32 @@ export const deleteFileCache = async (fileId: number) => {
   await deleteFile(`/cache/${fileId}`);
   await deleteFileCacheIndex(fileId);
 };
+
+export const getFileThumbnailCache = async (fileId: number) => {
+  const thumbnail = loadedThumbnails.get(fileId);
+  if (thumbnail) {
+    return thumbnail;
+  }
+
+  const thumbnailBuffer = await readFile(`/thumbnail/file/${fileId}`);
+  if (!thumbnailBuffer) return null;
+
+  const thumbnailUrl = getThumbnailUrl(thumbnailBuffer);
+  loadedThumbnails.set(fileId, thumbnailUrl);
+  return thumbnailUrl;
+};
+
+export const storeFileThumbnailCache = async (fileId: number, thumbnailBuffer: ArrayBuffer) => {
+  await writeFile(`/thumbnail/file/${fileId}`, thumbnailBuffer);
+  loadedThumbnails.set(fileId, getThumbnailUrl(thumbnailBuffer));
+};
+
+export const deleteFileThumbnailCache = async (fileId: number) => {
+  loadedThumbnails.delete(fileId);
+  await deleteFile(`/thumbnail/file/${fileId}`);
+};
+
+export const deleteAllFileThumbnailCaches = async () => {
+  loadedThumbnails.clear();
+  await deleteDirectory("/thumbnail/file");
+};