Move arrpc server into a worker thread to reduce stutters (#1053)

Co-authored-by: V <vendicated@riseup.net>

src/main/arrpc/worker.ts

@@ -0,0 +1,60 @@
+/*
+ * Vesktop, a desktop app aiming to give you a snappier Discord Experience
+ * Copyright (c) 2025 Vendicated and Vesktop contributors
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+import Server from "arrpc";
+import { randomUUID } from "crypto";
+import { MessagePort, workerData } from "worker_threads";
+
+import { ArRpcEvent, ArRpcHostEvent } from "./types";
+
+let server: any;
+
+type InviteCallback = (valid: boolean) => void;
+type LinkCallback = InviteCallback;
+
+const inviteCallbacks = new Map<string, InviteCallback>();
+const linkCallbacks = new Map<string, LinkCallback>();
+
+(async function () {
+    const { workerPort } = workerData as { workerPort: MessagePort };
+
+    server = await new Server();
+
+    server.on("activity", (data: any) => {
+        const event: ArRpcEvent = {
+            type: "activity",
+            data: JSON.stringify(data)
+        };
+        workerPort.postMessage(event);
+    });
+
+    server.on("invite", (invite: string, callback: InviteCallback) => {
+        const nonce = randomUUID();
+        inviteCallbacks.set(nonce, callback);
+
+        const event: ArRpcEvent = {
+            type: "invite",
+            data: invite,
+            nonce
+        };
+        workerPort.postMessage(event);
+    });
+
+    workerPort.on("message", (e: ArRpcHostEvent) => {
+        switch (e.type) {
+            case "ack-invite": {
+                inviteCallbacks.get(e.nonce)?.(e.data);
+                inviteCallbacks.delete(e.nonce);
+                break;
+            }
+            case "ack-link": {
+                linkCallbacks.get(e.nonce)?.(e.data);
+                linkCallbacks.delete(e.nonce);
+                break;
+            }
+        }
+    });
+})();