New attachment storage system

ts/util/encryptLegacyAttachment.ts

@@ -0,0 +1,71 @@
+// Copyright 2024 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import LRU from 'lru-cache';
+import type {
+  AddressableAttachmentType,
+  LocalAttachmentV2Type,
+} from '../types/Attachment';
+import { AttachmentDisposition } from './getLocalAttachmentUrl';
+
+let setCheck = false;
+
+const lru = new LRU<string, Promise<LocalAttachmentV2Type>>({
+  max: 1000,
+});
+
+export type EncryptLegacyAttachmentOptionsType = Readonly<{
+  disposition?: AttachmentDisposition;
+  readAttachmentData: (
+    attachment: Partial<AddressableAttachmentType>
+  ) => Promise<Uint8Array>;
+  writeNewAttachmentData: (data: Uint8Array) => Promise<LocalAttachmentV2Type>;
+}>;
+
+export async function encryptLegacyAttachment<
+  T extends Partial<AddressableAttachmentType>
+>(attachment: T, options: EncryptLegacyAttachmentOptionsType): Promise<T> {
+  // Not downloaded
+  if (!attachment.path) {
+    return attachment;
+  }
+
+  // Already upgraded
+  if (attachment.version === 2) {
+    return attachment;
+  }
+
+  const { disposition = AttachmentDisposition.Attachment } = options;
+  const cacheKey = `${disposition}:${attachment.path}`;
+
+  let promise = lru.get(cacheKey);
+  if (!promise) {
+    promise = doEncrypt(attachment, options);
+    lru.set(cacheKey, promise);
+  }
+  const modern = await promise;
+
+  return {
+    ...attachment,
+    ...modern,
+  };
+}
+
+async function doEncrypt<T extends Partial<AddressableAttachmentType>>(
+  attachment: T,
+  {
+    readAttachmentData,
+    writeNewAttachmentData,
+  }: EncryptLegacyAttachmentOptionsType
+): Promise<LocalAttachmentV2Type> {
+  const data = await readAttachmentData(attachment);
+  const result = await writeNewAttachmentData(data);
+
+  // Remove fully migrated attachments without references on next startup.
+  if (!setCheck) {
+    setCheck = true;
+    await window.storage.put('needOrphanedAttachmentCheck', true);
+  }
+
+  return result;
+}