Enable downloading attachments from backup CDN

ts/types/Attachment.ts

@@ -78,6 +78,14 @@ export type AttachmentType = {
   textAttachment?: TextAttachmentType;
   wasTooBig?: boolean;
 
+  incrementalMac?: string;
+  incrementalMacChunkSize?: number;
+
+  backupLocator?: {
+    mediaName: string;
+    cdnNumber?: number;
+  };
+
   /** Legacy field. Used only for downloading old attachments */
   id?: number;
 

ts/types/AttachmentDownload.ts

@@ -4,6 +4,11 @@ import { z } from 'zod';
 import { MIMETypeSchema, type MIMEType } from './MIME';
 import type { AttachmentType } from './Attachment';
 
+export enum MediaTier {
+  STANDARD = 'standard',
+  BACKUP = 'backup',
+}
+
 export const attachmentDownloadTypeSchema = z.enum([
   'long-message',
   'attachment',

ts/types/Util.ts

@@ -89,3 +89,6 @@ export type JSONWithUnknownFields<Value> = Value extends Record<
   : Value extends Array<infer E>
   ? ReadonlyArray<JSONWithUnknownFields<E>>
   : Value;
+
+export type WithRequiredProperties<T, P extends keyof T> = Omit<T, P> &
+  Required<Pick<T, P>>;

ts/types/backups.ts

@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: AGPL-3.0-only
 
 import type { BackupLevel } from '@signalapp/libsignal-client/zkgroup';
+import type { GetBackupCDNCredentialsResponseType } from '../textsecure/WebAPI';
 
 export type BackupCredentialType = Readonly<{
   credential: string;
@@ -18,3 +19,9 @@ export type BackupSignedPresentationType = Readonly<{
   headers: BackupPresentationHeadersType;
   level: BackupLevel;
 }>;
+
+export type BackupCdnReadCredentialType = Readonly<{
+  credentials: Readonly<GetBackupCDNCredentialsResponseType>;
+  retrievedAtMs: number;
+  cdnNumber: number;
+}>;