From e1892ff3704553ca09eb9c1b4e0d140acf261980 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Fri, 14 Feb 2020 23:16:44 -0500
Subject: [PATCH] Resolves crash upon File -> New..., Cancel; also ensures slow
 performance can't equal no progression.

---
 OSBindings/Mac/Clock Signal/Documents/MachineDocument.swift | 2 +-
 OSBindings/Mac/Clock Signal/Machine/CSMachine.mm            | 6 +-----
 2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/OSBindings/Mac/Clock Signal/Documents/MachineDocument.swift b/OSBindings/Mac/Clock Signal/Documents/MachineDocument.swift
index 72bfef8c2..54e85c1b0 100644
--- a/OSBindings/Mac/Clock Signal/Documents/MachineDocument.swift	
+++ b/OSBindings/Mac/Clock Signal/Documents/MachineDocument.swift	
@@ -84,7 +84,7 @@ class MachineDocument:
 	}
 
 	override func close() {
-		machine.stop()
+		machine?.stop()
 
 		activityPanel?.setIsVisible(false)
 		activityPanel = nil
diff --git a/OSBindings/Mac/Clock Signal/Machine/CSMachine.mm b/OSBindings/Mac/Clock Signal/Machine/CSMachine.mm
index 2130b06bb..58705ecb2 100644
--- a/OSBindings/Mac/Clock Signal/Machine/CSMachine.mm	
+++ b/OSBindings/Mac/Clock Signal/Machine/CSMachine.mm	
@@ -770,11 +770,7 @@ struct ActivityObserver: public Activity::Observer {
 		// Grab the time now and, therefore, the amount of time since the timer last fired
 		// (capped at half a second).
 		const auto timeNow = Time::nanos_now();
-		const auto duration = timeNow - lastTime;
-		if(duration > Time::Nanos(500'000'000)) {
-			lastTime = timeNow;
-			return;
-		}
+		const auto duration = std::min(timeNow - lastTime, Time::Nanos(10'000'000'000 / TICKS));
 
 		CGSize pixelSize;
 		BOOL splitAndSync = NO;