[WIP] Previewer Debug

Avalonia.sln

@@ -37,6 +37,7 @@ EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Shared", "Shared", "{A689DEF5-D50F-4975-8B72-124C9EB54066}"
 	ProjectSection(SolutionItems) = preProject
 		.editorconfig = .editorconfig
+		src\Shared\DebuggerHelper.cs = src\Shared\DebuggerHelper.cs
 		src\Shared\IsExternalInit.cs = src\Shared\IsExternalInit.cs
 		src\Shared\ModuleInitializer.cs = src\Shared\ModuleInitializer.cs
 		src\Shared\NullableAttributes.cs = src\Shared\NullableAttributes.cs

src/Avalonia.Build.Tasks/Avalonia.Build.Tasks.csproj

@@ -117,6 +117,7 @@
       <Compile Include="..\Avalonia.Base\Metadata\NullableAttributes.cs" Link="NullableAttributes.cs" />
       <Compile Include="..\Avalonia.Base\Compatibility\TrimmingAttributes.cs" Link="TrimmingAttributes.cs" Visible="False" />
       <Compile Include="..\Avalonia.Base\Utilities\SpanHelpers.cs" Link="Utilities\SpanHelpers.cs" />
+      <Compile Include="..\Shared\DebuggerHelper.cs" Link="DebuggerHelper.cs" />
       <Compile Include="..\Shared\StringCompatibilityExtensions.cs" Link="Compatibility\StringCompatibilityExtensions.cs" />
       <Compile Include="..\Shared\IsExternalInit.cs" Link="Compatibility\IsExternalInit.cs" />
       <Compile Remove="../Markup/Avalonia.Markup.Xaml.Loader\xamlil.github\**\obj\**\*.cs" />

src/Avalonia.Build.Tasks/XamlCompilerTaskExecutor.cs

@@ -111,32 +111,7 @@ public CompileResult(bool success, bool writtenFile = false)
         {
             if (debuggerLaunch)
             {
-                // According this https://docs.microsoft.com/en-us/dotnet/api/system.diagnostics.debugger.launch?view=net-6.0#remarks
-                // documentation, on not windows platform Debugger.Launch() always return true without running a debugger.
-                if (System.Diagnostics.Debugger.Launch())
-                {
-                    // Set timeout at 1 minut.
-                    var time = new System.Diagnostics.Stopwatch();
-                    var timeout = TimeSpan.FromMinutes(1);
-                    time.Start();
-
-                    // wait for the debugger to be attacked or timeout.
-                    while (!System.Diagnostics.Debugger.IsAttached && time.Elapsed < timeout)
-                    {
-                        engine.LogMessage($"[PID:{System.Diagnostics.Process.GetCurrentProcess().Id}] Wating attach debugger. Elapsed {time.Elapsed}...", MessageImportance.High);
-                        System.Threading.Thread.Sleep(100);
-                    }
-
-                    time.Stop();
-                    if (time.Elapsed >= timeout)
-                    {
-                        engine.LogMessage("Wating attach debugger timeout.", MessageImportance.Normal);
-                    }
-                }
-                else
-                {
-                    engine.LogMessage("Debugging cancelled.", MessageImportance.Normal);
-                }
+                Avalonia.Utilities.DebuggerHelper.Launch(m => engine.LogMessage(m, MessageImportance.High));
             }
 
             // Some transformers might need to parse "avares://" Uri.

src/Avalonia.DesignerSupport/Avalonia.DesignerSupport.csproj

@@ -14,6 +14,7 @@
   <ItemGroup>
     <EmbeddedResource Include="Remote\HtmlTransport\webapp\build\**\*.gz" />
     <EmbeddedResource Condition="'$(Configuration)' == 'Debug'" Remove="Remote\HtmlTransport\webapp\build\**\*.map.gz" />
+    <Compile Include="..\Shared\DebuggerHelper.cs" Link="DebuggerHelper.cs" />
     <ProjectReference Include="..\Markup\Avalonia.Markup.Xaml\Avalonia.Markup.Xaml.csproj" />
     <ProjectReference Include="..\Markup\Avalonia.Markup\Avalonia.Markup.csproj" />
     <ProjectReference Include="..\Avalonia.Base\Avalonia.Base.csproj" />

src/Avalonia.DesignerSupport/Remote/RemoteDesignerEntryPoint.cs

@@ -27,6 +27,7 @@ class CommandLineArgs
             public Uri HtmlMethodListenUri { get; set; }
             public string Method { get; set; } = Methods.AvaloniaRemote;
             public string SessionId { get; set; } = Guid.NewGuid().ToString();
+            public bool Debug { get; set; }
         }
 
         internal static class Methods
@@ -92,6 +93,11 @@ static CommandLineArgs ParseCommandLineArgs(string[] args)
                         next = a => rv.HtmlMethodListenUri = new Uri(a, UriKind.Absolute);
                     else if (arg == "--session-id")
                         next = a => rv.SessionId = a;
+                    else if (arg == "--debug")
+                    {
+                        rv.Debug = true;
+                        next = null;
+                    }
                     else if (rv.AppPath == null)
                         rv.AppPath = arg;
                     else
@@ -169,6 +175,10 @@ class AppInitializer : IAppInitializer
         public static void Main(string[] cmdline)
         {
             var args = ParseCommandLineArgs(cmdline);
+            if (args.Debug)
+            {
+                Avalonia.Utilities.DebuggerHelper.Launch(Log);
+            }
             var transport = CreateTransport(args);
             if (transport is ITransportWithEnforcedMethod enforcedMethod)
                 args.Method = enforcedMethod.PreviewerMethod;
@@ -178,15 +188,15 @@ public static void Main(string[] cmdline)
             Design.IsDesignMode = true;
             Log($"Obtaining AppBuilder instance from {entryPoint.DeclaringType!.FullName}");
             var appBuilder = AppBuilder.Configure(entryPoint.DeclaringType);
-            var initializer =(IAppInitializer)Activator.CreateInstance(typeof(AppInitializer));
+            var initializer = (IAppInitializer)Activator.CreateInstance(typeof(AppInitializer));
             transport = initializer.ConfigureApp(transport, args, appBuilder);
             s_transport = transport;
             transport.OnMessage += OnTransportMessage;
             transport.OnException += (t, e) => Die(e.ToString());
             transport.Start();
             Log("Sending StartDesignerSessionMessage");
-            transport.Send(new StartDesignerSessionMessage {SessionId = args.SessionId});
-            
+            transport.Send(new StartDesignerSessionMessage { SessionId = args.SessionId });
+
             Dispatcher.UIThread.MainLoop(CancellationToken.None);
         }
 
@@ -236,7 +246,7 @@ private static void RebuildPreFlight()
                 try
                 {
                     s_currentWindow = DesignWindowLoader.LoadDesignerWindow(xaml.Xaml, xaml.AssemblyPath, xaml.XamlFileProjectPath, s_lastRenderScaling);
-                    s_transport.Send(new UpdateXamlResultMessage(){Handle = s_currentWindow.PlatformImpl?.Handle?.Handle.ToString()});
+                    s_transport.Send(new UpdateXamlResultMessage() { Handle = s_currentWindow.PlatformImpl?.Handle?.Handle.ToString() });
                 }
                 catch (Exception e)
                 {

src/Shared/DebuggerHelper.cs

@@ -0,0 +1,36 @@
+using System;
+
+namespace Avalonia.Utilities;
+
+internal sealed class DebuggerHelper
+{
+	public static void Launch(Action<string> log)
+    {
+        // According this https://docs.microsoft.com/en-us/dotnet/api/system.diagnostics.debugger.launch?view=net-6.0#remarks
+        // documentation, on not windows platform Debugger.Launch() always return true without running a debugger.
+        if (System.Diagnostics.Debugger.Launch())
+        {
+            // Set timeout at 1 minut.
+            var time = new System.Diagnostics.Stopwatch();
+            var timeout = TimeSpan.FromMinutes(1);
+            time.Start();
+
+            // wait for the debugger to be attached or timeout.
+            while (!System.Diagnostics.Debugger.IsAttached && time.Elapsed < timeout)
+            {
+                log?.Invoke($"[PID:{System.Diagnostics.Process.GetCurrentProcess().Id}] Wating attach debugger. Elapsed {time.Elapsed}...");
+                System.Threading.Thread.Sleep(100);
+            }
+
+            time.Stop();
+            if (time.Elapsed >= timeout)
+            {
+                log?.Invoke("Wating attach debugger timeout.");
+            }
+        }
+        else
+        {
+            log?.Invoke("Debugging cancelled.");
+        }
+    }
+}