Fix native capture countdown startup lag

electron/ipc/cursor/interaction.test.ts

@@ -11,7 +11,21 @@ vi.mock("electron", () => ({
 	},
 }));
 
-import { repairBundledUiohookBinaryForCurrentArch } from "./interaction";
+import {
+	repairBundledUiohookBinaryForCurrentArch,
+	shouldStartGlobalInteractionHook,
+} from "./interaction";
+
+describe("shouldStartGlobalInteractionHook", () => {
+	it("does not start the synchronous uiohook event tap on macOS", () => {
+		expect(shouldStartGlobalInteractionHook("darwin")).toBe(false);
+	});
+
+	it("keeps global interaction capture enabled on Windows and Linux", () => {
+		expect(shouldStartGlobalInteractionHook("win32")).toBe(true);
+		expect(shouldStartGlobalInteractionHook("linux")).toBe(true);
+	});
+});
 
 describe("repairBundledUiohookBinaryForCurrentArch", () => {
 	const tempRoots: string[] = [];
@@ -68,4 +82,4 @@ describe("repairBundledUiohookBinaryForCurrentArch", () => {
 		expect(repaired).toBe(false);
 		expect(await fs.readFile(buildPath, "utf8")).toBe("existing-build");
 	});
-});
+});

electron/ipc/cursor/interaction.ts

@@ -1,21 +1,26 @@
 import fs from "node:fs";
 import { createRequire } from "node:module";
 import path from "node:path";
-import type { HookMouseEvent, UiohookLike, UiohookModuleNamespace, CursorInteractionType } from "../types";
 import {
-	isCursorCaptureActive,
-	interactionCaptureCleanup,
-	setInteractionCaptureCleanup,
 	hasLoggedInteractionHookFailure,
-	setHasLoggedInteractionHookFailure,
+	interactionCaptureCleanup,
+	isCursorCaptureActive,
 	lastLeftClick,
+	setHasLoggedInteractionHookFailure,
+	setInteractionCaptureCleanup,
 	setLastLeftClick,
 	setLinuxCursorScreenPoint,
 } from "../state";
+import type {
+	CursorInteractionType,
+	HookMouseEvent,
+	UiohookLike,
+	UiohookModuleNamespace,
+} from "../types";
 import {
-	getNormalizedCursorPoint,
 	getCursorCaptureElapsedMs,
 	getHookCursorScreenPoint,
+	getNormalizedCursorPoint,
 	isCursorCapturePaused,
 	pushCursorSample,
 } from "./telemetry";
@@ -172,6 +177,62 @@ function loadUiohookModule() {
 	}
 }
 
+export function shouldStartGlobalInteractionHook(platform: NodeJS.Platform = process.platform) {
+	// On macOS, uiohook can block forever while its native event tap starts
+	// (notably when Accessibility permission is unavailable or stale). Because
+	// start() executes synchronously, that freezes Electron's main thread and
+	// makes every window, including the recording HUD, unresponsive. Cursor
+	// position and visual-state telemetry still come from the existing native
+	// macOS monitor and Electron sampler.
+	return platform !== "darwin";
+}
+
+export function recordCursorMouseDown(button: 1 | 2 | 3) {
+	if (!isCursorCaptureActive || isCursorCapturePaused()) {
+		return;
+	}
+
+	const point = getNormalizedCursorPoint();
+	if (!point) {
+		return;
+	}
+
+	const timeMs = getCursorCaptureElapsedMs();
+	let interactionType: CursorInteractionType = "click";
+
+	if (button === 2) {
+		interactionType = "right-click";
+	} else if (button === 3) {
+		interactionType = "middle-click";
+	} else {
+		const thresholdMs = 350;
+		const distance = lastLeftClick
+			? Math.hypot(point.cx - lastLeftClick.cx, point.cy - lastLeftClick.cy)
+			: Number.POSITIVE_INFINITY;
+
+		if (lastLeftClick && timeMs - lastLeftClick.timeMs <= thresholdMs && distance <= 0.04) {
+			interactionType = "double-click";
+		}
+
+		setLastLeftClick({ timeMs, cx: point.cx, cy: point.cy });
+	}
+
+	pushCursorSample(point.cx, point.cy, timeMs, interactionType);
+}
+
+export function recordCursorMouseUp() {
+	if (!isCursorCaptureActive || isCursorCapturePaused()) {
+		return;
+	}
+
+	const point = getNormalizedCursorPoint();
+	if (!point) {
+		return;
+	}
+
+	pushCursorSample(point.cx, point.cy, getCursorCaptureElapsedMs(), "mouseup");
+}
+
 export async function startInteractionCapture() {
 	if (!isCursorCaptureActive) {
 		return;
@@ -181,6 +242,11 @@ export async function startInteractionCapture() {
 		return;
 	}
 
+	if (!shouldStartGlobalInteractionHook()) {
+		console.warn("[CursorTelemetry] Skipping the blocking global interaction hook on macOS.");
+		return;
+	}
+
 	stopInteractionCapture();
 
 	try {
@@ -203,63 +269,15 @@ export async function startInteractionCapture() {
 		}
 
 		const onMouseDown = (event: HookMouseEvent) => {
-			if (!isCursorCaptureActive || isCursorCapturePaused()) {
-				return;
-			}
-
-			const point = getNormalizedCursorPoint();
-			if (!point) {
-				return;
-			}
-
-			const timeMs = getCursorCaptureElapsedMs();
-			const button = getHookMouseButton(event);
-			let interactionType: CursorInteractionType = "click";
-
-			if (button === 2) {
-				interactionType = "right-click";
-			} else if (button === 3) {
-				interactionType = "middle-click";
-			} else {
-				const thresholdMs = 350;
-				const distance = lastLeftClick
-					? Math.hypot(point.cx - lastLeftClick.cx, point.cy - lastLeftClick.cy)
-					: Number.POSITIVE_INFINITY;
-
-				if (
-					lastLeftClick &&
-					timeMs - lastLeftClick.timeMs <= thresholdMs &&
-					distance <= 0.04
-				) {
-					interactionType = "double-click";
-				}
-
-				setLastLeftClick({ timeMs, cx: point.cx, cy: point.cy });
-			}
-
-			pushCursorSample(point.cx, point.cy, timeMs, interactionType);
+			recordCursorMouseDown(getHookMouseButton(event));
 		};
 
 		const onMouseUp = () => {
-			if (!isCursorCaptureActive || isCursorCapturePaused()) {
-				return;
-			}
-
-			const point = getNormalizedCursorPoint();
-			if (!point) {
-				return;
-			}
-
-			const timeMs = getCursorCaptureElapsedMs();
-			pushCursorSample(point.cx, point.cy, timeMs, "mouseup");
+			recordCursorMouseUp();
 		};
 
 		const onMouseMove = (event: HookMouseEvent) => {
-			if (
-				process.platform !== "linux" ||
-				!isCursorCaptureActive ||
-				isCursorCapturePaused()
-			) {
+			if (process.platform !== "linux" || !isCursorCaptureActive || isCursorCapturePaused()) {
 				return;
 			}
 

electron/ipc/cursor/monitor.ts

@@ -2,7 +2,7 @@ import { spawn } from "node:child_process";
 import { constants as fsConstants } from "node:fs";
 import fs from "node:fs/promises";
 import { BrowserWindow } from "electron";
-import type { CursorVisualType } from "../types";
+import { ensureNativeCursorMonitorBinary, getCursorMonitorExePath } from "../paths/binaries";
 import {
 	currentCursorVisualType,
 	nativeCursorMonitorOutputBuffer,
@@ -11,7 +11,8 @@ import {
 	setNativeCursorMonitorOutputBuffer,
 	setNativeCursorMonitorProcess,
 } from "../state";
-import { getCursorMonitorExePath, ensureNativeCursorMonitorBinary } from "../paths/binaries";
+import type { CursorVisualType } from "../types";
+import { recordCursorMouseDown, recordCursorMouseUp } from "./interaction";
 
 export function emitCursorStateChanged(cursorType: CursorVisualType) {
 	BrowserWindow.getAllWindows().forEach((window) => {
@@ -27,6 +28,17 @@ export function handleCursorMonitorStdout(chunk: Buffer) {
 	setNativeCursorMonitorOutputBuffer(lines.pop() ?? "");
 
 	for (const line of lines) {
+		const interactionMatch = line.match(/^INTERACTION:(mousedown|mouseup)(?::([123]))?$/);
+		if (interactionMatch) {
+			if (interactionMatch[1] === "mouseup") {
+				recordCursorMouseUp();
+			} else {
+				const button = Number(interactionMatch[2]);
+				recordCursorMouseDown(button === 2 || button === 3 ? button : 1);
+			}
+			continue;
+		}
+
 		const match = line.match(/^STATE:(.+)$/);
 		if (!match) continue;
 		const next = match[1].trim() as CursorVisualType;

electron/ipc/recording/mac.ts

@@ -77,6 +77,49 @@ export function waitForNativeCaptureStart(process: ChildProcessWithoutNullStream
 	});
 }
 
+export function waitForNativeCaptureCommand(
+	process: ChildProcessWithoutNullStreams,
+	marker: "Recording paused" | "Recording resumed",
+) {
+	return new Promise<void>((resolve, reject) => {
+		const timer = setTimeout(() => {
+			cleanup();
+			reject(new Error(`Timed out waiting for ScreenCaptureKit helper: ${marker}`));
+		}, 5000);
+
+		let stdoutBuffer = "";
+		const onStdout = (chunk: Buffer) => {
+			stdoutBuffer += chunk.toString();
+			if (stdoutBuffer.includes(marker)) {
+				cleanup();
+				resolve();
+			}
+		};
+		const onError = (error: Error) => {
+			cleanup();
+			reject(error);
+		};
+		const onExit = (code: number | null) => {
+			cleanup();
+			reject(
+				new Error(
+					`Native capture helper exited before ${marker.toLowerCase()} (code ${code ?? "unknown"})`,
+				),
+			);
+		};
+		const cleanup = () => {
+			clearTimeout(timer);
+			process.stdout.off("data", onStdout);
+			process.off("error", onError);
+			process.off("exit", onExit);
+		};
+
+		process.stdout.on("data", onStdout);
+		process.once("error", onError);
+		process.once("exit", onExit);
+	});
+}
+
 export function waitForNativeCaptureStop(process: ChildProcessWithoutNullStreams) {
 	return new Promise<string>((resolve, reject) => {
 		const onClose = (code: number | null) => {

electron/ipc/register/recording.ts

@@ -65,6 +65,7 @@ import {
 	finalizeStoredVideo,
 	muxNativeMacRecordingWithAudio,
 	recoverNativeMacCaptureOutput,
+	waitForNativeCaptureCommand,
 	waitForNativeCaptureStart,
 	waitForNativeCaptureStop,
 } from "../recording/mac";
@@ -1305,7 +1306,12 @@ export function registerRecordingHandlers(
 		}
 
 		try {
+			const commandApplied = waitForNativeCaptureCommand(
+				nativeCaptureProcess,
+				"Recording paused",
+			);
 			nativeCaptureProcess.stdin.write("pause\n");
+			await commandApplied;
 			setNativeCapturePaused(true);
 			return { success: true };
 		} catch (error) {
@@ -1356,7 +1362,12 @@ export function registerRecordingHandlers(
 		}
 
 		try {
+			const commandApplied = waitForNativeCaptureCommand(
+				nativeCaptureProcess,
+				"Recording resumed",
+			);
 			nativeCaptureProcess.stdin.write("resume\n");
+			await commandApplied;
 			setNativeCapturePaused(false);
 			return { success: true };
 		} catch (error) {