From 64193ff1b0cb3cc9770488512277695830cc5a5b Mon Sep 17 00:00:00 2001
From: Sinai <49360850+sinai-dev@users.noreply.github.com>
Date: Mon, 21 Feb 2022 01:45:46 +1100
Subject: [PATCH] Use a patch instead of manual check on every property

---
 src/CacheObject/CacheProperty.cs    |  2 --
 src/Runtime/UnityCrashPrevention.cs | 31 +++++++++++++++++++++--------
 2 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/src/CacheObject/CacheProperty.cs b/src/CacheObject/CacheProperty.cs
index d4ed940..fee7b9e 100644
--- a/src/CacheObject/CacheProperty.cs
+++ b/src/CacheObject/CacheProperty.cs
@@ -30,8 +30,6 @@ namespace UnityExplorer.CacheObject
         {
             try
             {
-                UnityCrashPrevention.CheckPropertyInfoEvaluation(this);
-
                 object ret;
                 if (HasArguments)
                     ret = PropertyInfo.GetValue(DeclaringInstance, this.Evaluator.TryParseArguments());
diff --git a/src/Runtime/UnityCrashPrevention.cs b/src/Runtime/UnityCrashPrevention.cs
index 2ed142a..98f3032 100644
--- a/src/Runtime/UnityCrashPrevention.cs
+++ b/src/Runtime/UnityCrashPrevention.cs
@@ -1,4 +1,5 @@
-using System;
+using HarmonyLib;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
@@ -7,17 +8,31 @@ using UnityExplorer.CacheObject;
 
 namespace UnityExplorer.Runtime
 {
-    public static class UnityCrashPrevention
+    internal static class UnityCrashPrevention
     {
-        public static void CheckPropertyInfoEvaluation(CacheProperty cacheProp)
+        internal static void Init()
         {
-            if (cacheProp.PropertyInfo.Name == "renderingDisplaySize"
-                && cacheProp.Owner.Target is Canvas canvas
-                && canvas.renderMode == RenderMode.WorldSpace
-                && !canvas.worldCamera)
+            try
             {
-                throw new Exception("Canvas is set to RenderMode.WorldSpace but has no worldCamera, cannot get value.");
+                ExplorerCore.Harmony.PatchAll(typeof(UnityCrashPrevention));
+                ExplorerCore.Log("Initialized UnityCrashPrevention.");
             }
+            catch //(Exception ex)
+            {
+                //ExplorerCore.Log($"Exception setting up Canvas crash prevention patch: {ex}");
+            }
+        }
+
+        // In Unity 2020 they introduced "Canvas.renderingDisplaySize".
+        // If you try to get the value on a Canvas which has a renderMode value of WorldSpace and no worldCamera set,
+        // the game will Crash when Unity tries to read from a null ptr (I think).
+        [HarmonyPatch(typeof(Canvas), "renderingDisplaySize", MethodType.Getter)]
+        [HarmonyPrefix]
+        internal static void Prefix(Canvas __instance)
+        {
+            if (__instance.renderMode == RenderMode.WorldSpace && !__instance.worldCamera)
+                throw new InvalidOperationException(
+                    "Canvas is set to RenderMode.WorldSpace but not worldCamera is set, cannot get renderingDisplaySize.");
         }
     }
 }