From 2364b57f40e437b223a39c86fc2e686f416a5fa5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Damian=20B=C3=BCchel?= <damian.buechel@let.ethz.ch>
Date: Tue, 11 May 2021 01:32:50 +0200
Subject: [PATCH] SEBWIN-488: Implemented pause before resetting or terminating
 browser in order to prevent application crashes.

---
 SafeExamBrowser.Browser/BrowserApplication.cs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/SafeExamBrowser.Browser/BrowserApplication.cs b/SafeExamBrowser.Browser/BrowserApplication.cs
index 0fa519ce..f8bac541 100644
--- a/SafeExamBrowser.Browser/BrowserApplication.cs
+++ b/SafeExamBrowser.Browser/BrowserApplication.cs
@@ -10,6 +10,7 @@ using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Threading;
 using CefSharp;
 using CefSharp.WinForms;
 using SafeExamBrowser.Applications.Contracts;
@@ -119,6 +120,7 @@ namespace SafeExamBrowser.Browser
 		public void Terminate()
 		{
 			logger.Info("Initiating termination...");
+			AwaitReady();
 
 			foreach (var instance in instances)
 			{
@@ -145,6 +147,15 @@ namespace SafeExamBrowser.Browser
 			}
 		}
 
+		private void AwaitReady()
+		{
+			// We apparently need to let the browser finish any pending work before attempting to reset or terminate it, especially if the
+			// reset or termination is initiated automatically (e.g. by a quit URL). Otherwise, the engine will crash on some occasions, seemingly
+			// when it can't finish handling its events (like ChromiumWebBrowser.LoadError).
+
+			Thread.Sleep(500);
+		}
+
 		private void CreateNewInstance(string url = null)
 		{
 			var id = ++instanceIdCounter;
@@ -353,6 +364,7 @@ namespace SafeExamBrowser.Browser
 		private void Instance_ResetRequested()
 		{
 			logger.Info("Attempting to reset browser...");
+			AwaitReady();
 
 			foreach (var instance in instances)
 			{