From f79065b795ae720d3bc05271745d05a8bf8ae4f0 Mon Sep 17 00:00:00 2001
From: Dariusz Komosinski <darek.komosinski@gmail.com>
Date: Mon, 26 Oct 2020 11:22:23 +0100
Subject: [PATCH] Handle compositor creation failure and add logging.

---
 .../Composition/CompositionConnector.cs       | 32 +++++++++++++++++++
 src/Windows/Avalonia.Win32/Win32GlManager.cs  | 10 +++---
 2 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/src/Windows/Avalonia.Win32/Composition/CompositionConnector.cs b/src/Windows/Avalonia.Win32/Composition/CompositionConnector.cs
index fc18b623bf..5bdc0cd410 100644
--- a/src/Windows/Avalonia.Win32/Composition/CompositionConnector.cs
+++ b/src/Windows/Avalonia.Win32/Composition/CompositionConnector.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Runtime.InteropServices;
+using Avalonia.Logging;
 using Avalonia.OpenGL;
 using Avalonia.OpenGL.Angle;
 using Avalonia.OpenGL.Egl;
@@ -43,6 +44,37 @@ namespace Avalonia.Win32
         [DllImport("coremessaging.dll", EntryPoint = "CreateDispatcherQueueController", CharSet = CharSet.Unicode)]
         internal static extern IntPtr CreateDispatcherQueueController(DispatcherQueueOptions options, out IntPtr dispatcherQueueController);
 
+        public static CompositionConnector TryCreate(EglPlatformOpenGlInterface egl)
+        {
+            const int majorRequired = 10;
+            const int buildRequired = 16299;
+
+            var majorInstalled = Win32Platform.WindowsVersion.Major;
+            var buildInstalled = Win32Platform.WindowsVersion.Build;
+            
+            if (majorInstalled >= majorRequired &&
+                buildInstalled >= buildRequired)
+            {
+                try
+                {
+                    return new CompositionConnector(egl);
+                }
+                catch (Exception e)
+                {
+                    Logger.TryGet(LogEventLevel.Error, "WinUIComposition")?.Log(null, "Unable to initialize WinUI compositor: {0}", e);
+
+                    return null;
+                }
+            }
+
+            var osVersionNotice = $"Windows {majorRequired} Build {buildRequired} is required. Your machine has Windows {majorInstalled} Build {buildInstalled} installed.";
+
+            Logger.TryGet(LogEventLevel.Warning, "WinUIComposition")?.Log(null,
+                $"Unable to initialize WinUI compositor: {osVersionNotice}");
+
+            return null;
+        }
+        
         public CompositionConnector(EglPlatformOpenGlInterface egl)
         {
             EnsureDispatcherQueue();
diff --git a/src/Windows/Avalonia.Win32/Win32GlManager.cs b/src/Windows/Avalonia.Win32/Win32GlManager.cs
index 6a6ce2ec3c..4363b5fd29 100644
--- a/src/Windows/Avalonia.Win32/Win32GlManager.cs
+++ b/src/Windows/Avalonia.Win32/Win32GlManager.cs
@@ -1,3 +1,4 @@
+using System;
 using Avalonia.OpenGL;
 using Avalonia.OpenGL.Angle;
 using Avalonia.OpenGL.Egl;
@@ -23,11 +24,12 @@ namespace Avalonia.Win32
                     var egl = EglPlatformOpenGlInterface.TryCreate(() => new AngleWin32EglDisplay());
 
                     if (egl is { } &&
-                    opts?.UseWindowsUIComposition == true &&
-                    Win32Platform.WindowsVersion.Major >= 10 &&
-                    Win32Platform.WindowsVersion.Build >= 16299)
+                        opts?.UseWindowsUIComposition == true)
                     {
-                        AvaloniaLocator.CurrentMutable.BindToSelf(new CompositionConnector(egl));
+                        var compositionConnector = CompositionConnector.TryCreate(egl);
+
+                        if (compositionConnector != null)
+                            AvaloniaLocator.CurrentMutable.BindToSelf(compositionConnector);
                     }
 
                     return egl;