desktop: make tauri attachments filesystem-only

packages/app/src/desktop/attachments/desktop-preview-url.ts

@@ -0,0 +1,61 @@
+import type { AttachmentMetadata } from "@/attachments/types";
+import { fileUriToPath } from "@/attachments/utils";
+import { invokeDesktopCommand } from "@/desktop/tauri/invoke-desktop-command";
+
+function base64ToUint8Array(base64: string): Uint8Array {
+  const binary = atob(base64);
+  const bytes = new Uint8Array(binary.length);
+  for (let i = 0; i < binary.length; i += 1) {
+    bytes[i] = binary.charCodeAt(i);
+  }
+  return bytes;
+}
+
+const activeObjectUrls = new Set<string>();
+
+export async function readDesktopFileBase64(pathOrUri: string): Promise<string> {
+  return await invokeDesktopCommand<string>("read_file_base64", {
+    path: fileUriToPath(pathOrUri),
+  });
+}
+
+export async function resolveDesktopPreviewUrl(
+  attachment: AttachmentMetadata
+): Promise<string> {
+  const base64 = await readDesktopFileBase64(attachment.storageKey);
+
+  if (
+    typeof URL !== "undefined" &&
+    typeof URL.createObjectURL === "function"
+  ) {
+    const bytes = base64ToUint8Array(base64);
+    const buffer = new ArrayBuffer(bytes.byteLength);
+    new Uint8Array(buffer).set(bytes);
+    const blob = new Blob([buffer], { type: attachment.mimeType });
+    const objectUrl = URL.createObjectURL(blob);
+    activeObjectUrls.add(objectUrl);
+    return objectUrl;
+  }
+
+  return `data:${attachment.mimeType};base64,${base64}`;
+}
+
+export async function releaseDesktopPreviewUrl(input: {
+  url: string;
+}): Promise<void> {
+  if (!activeObjectUrls.has(input.url)) {
+    return;
+  }
+  activeObjectUrls.delete(input.url);
+
+  if (typeof URL !== "undefined" && typeof URL.revokeObjectURL === "function") {
+    URL.revokeObjectURL(input.url);
+  }
+}
+
+export const __desktopPreviewUrlTestUtils = {
+  base64ToUint8Array,
+  clearActiveObjectUrls: () => {
+    activeObjectUrls.clear();
+  },
+};