feat(hotrestart): [iOS] Add support for VS 2022 hot restart

(cherry picked from commit e69d507)

# Conflicts:
#	src/SourceGenerators/SourceGeneratorHelpers/Helpers/PlatformHelper.cs

doc/articles/get-started-vs-2022.md

@@ -96,7 +96,9 @@ To create an Uno Platform app:
 
       ![Visual Studio - "Debug toolbar" drop-down selecting the "net7.0-ios" framework](Assets/quick-start/net7-ios-debug.png)
 
-    - Select an active device
+    - Select:
+      - An active device, if your IDE is connected to a macOS Host
+      - A [local device using Hot Restart](https://learn.microsoft.com/en-us/xamarin/xamarin-forms/deploy-test/hot-restart), to debug your application without connecting to a mac
 1. To debug the **Android** platform:
     - Right click on the `MyApp.Mobile` project, select **Set as startup project**
     - In the **Debug toolbar** drop down, select framework `net7.0-android`

src/SourceGenerators/SourceGeneratorHelpers/Helpers/PlatformHelper.cs

@@ -32,6 +32,7 @@ public static bool IsValidPlatform(GeneratorExecutionContext context)
 		public static bool IsAndroid(GeneratorExecutionContext context)
 			=> context.GetMSBuildPropertyValue("AndroidApplication")?.Equals("true", StringComparison.OrdinalIgnoreCase) ?? false;
 
+<<<<<<< HEAD
 		public static bool IsXamariniOS(GeneratorExecutionContext context)
 			=> context.GetMSBuildPropertyValue("ProjectTypeGuidsProperty")?.Equals("{FEACFBD2-3405-455C-9665-78FE426C6842},{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}", StringComparison.OrdinalIgnoreCase) ?? false;
 
@@ -40,6 +41,11 @@ public static bool IsXamarinMacOs(GeneratorExecutionContext context)
 
 		public static bool IsExe(GeneratorExecutionContext context)
 			=> context.GetMSBuildPropertyValue("OutputType")?.Equals("Exe", StringComparison.OrdinalIgnoreCase) ?? false;
+=======
+		public static bool IsIOS(GeneratorExecutionContext context)
+			=> context.GetMSBuildPropertyValue("RuntimeIdentifier") is { Length: > 0 } rid
+				&& rid.StartsWith("ios", StringComparison.OrdinalIgnoreCase);
+>>>>>>> e69d5071e2 (feat(hotrestart): [iOS] Add support for VS 2022 hot restart)
 
 		public static bool IsUnoHead(GeneratorExecutionContext context)
 			=> context.GetMSBuildPropertyValue("IsUnoHead")?.Equals("true", StringComparison.OrdinalIgnoreCase) ?? false;

src/SourceGenerators/Uno.UI.SourceGenerators/Content/Uno.UI.SourceGenerators.props

@@ -97,6 +97,8 @@
 		<CompilerVisibleProperty Include="IsHotReloadHost" />
 		<CompilerVisibleProperty Include="UnoUseXamlReaderHotReload" />
 		<CompilerVisibleProperty Include="IsUnoHead" />
+		<CompilerVisibleProperty Include="UnoDisableHotRestartHelperGeneration" />
+		<CompilerVisibleProperty Include="RuntimeIdentifier" />
 
 		<CompilerVisibleProperty Include="UseWPF" />
 		<CompilerVisibleProperty Include="IsUnoHead" />

src/SourceGenerators/Uno.UI.SourceGenerators/HotRestart/HotRestartGenerator.cs

@@ -0,0 +1,351 @@
+#nullable enable
+
+using System;
+using System.Linq;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CSharp;
+using Uno.UI.SourceGenerators.Helpers;
+using System.Diagnostics;
+using Uno.Extensions;
+using Uno.Roslyn;
+
+namespace Uno.UI.SourceGenerators.HotRestart
+{
+	[Generator]
+	public class HotRestartGenerator : ISourceGenerator
+	{
+		public void Initialize(GeneratorInitializationContext context)
+		{
+		}
+
+		public void Execute(GeneratorExecutionContext context)
+		{
+			if (!DesignTimeHelper.IsDesignTime(context)
+				&& PlatformHelper.IsIOS(context)
+				&& PlatformHelper.IsUnoHead(context))
+			{
+				var generator = new Generator(context);
+				generator.Run();
+			}
+		}
+		private class Generator
+		{
+			private readonly GeneratorExecutionContext _context;
+
+			private INamedTypeSymbol? _mauiAppDelegate;
+
+			public Generator(GeneratorExecutionContext context)
+			{
+				_context = context;
+			}
+
+			public void Run()
+			{
+				if (!IsGenerationEnabled())
+				{
+					return;
+				}
+
+				_mauiAppDelegate = _context.Compilation.GetTypeByMetadataName("Microsoft.Maui.MauiUIApplicationDelegate");
+
+				var builder = new IndentedStringBuilder();
+				builder.AppendLineIndented("#if DEBUG");
+				builder.AppendLineIndented("// <auto-generated>");
+				builder.AppendLineIndented("// *************************************************************");
+				builder.AppendLineIndented($"// This file has been generated by Uno.UI ({nameof(HotRestartGenerator)})");
+				builder.AppendLineIndented("// *************************************************************");
+				builder.AppendLineIndented("// </auto-generated>");
+				builder.AppendLine();
+				builder.AppendLineIndented("using System;");
+				builder.AppendLine();
+
+				TryGenerateMAUIAppDelegate(builder);
+				GenerateHotRestartDelegate(builder);
+				builder.AppendLineIndented("#endif");
+
+				_context.AddSource("HotRestartHelper", builder.ToString());
+			}
+
+			private bool IsGenerationEnabled()
+				=> bool.TryParse(_context.GetMSBuildPropertyValue("UnoDisableHotRestartHelperGeneration", "false"), out var result) ? result : true;
+
+			private void GenerateHotRestartDelegate(IndentedStringBuilder builder)
+			{
+				builder.AppendLineIndented("[global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]");
+				using (builder.BlockInvariant("internal class __UnoHotRestartDelegate : global::Microsoft.Maui.MauiUIApplicationDelegate"))
+				{
+					using (builder.BlockInvariant("public override bool FinishedLaunching(global::UIKit.UIApplication uiApplication, global::Foundation.NSDictionary launchOptions)"))
+					{
+						var appType = GetApplicationDefinitionType();
+
+						builder.AppendLineIndented($"#if HAS_UNO_WINUI");
+						builder.AppendLineIndented($"Microsoft.UI.Xaml.Application.Start(_ => new {appType}());");
+						builder.AppendLineIndented($"#else");
+						builder.AppendLineIndented($"Windows.UI.Xaml.Application.Start(_ => new {appType}());");
+						builder.AppendLineIndented($"#endif");
+						builder.AppendLineIndented("return base.FinishedLaunching(uiApplication, launchOptions);");
+					}
+				}
+			}
+
+			private string GetApplicationDefinitionType()
+			{
+				var appDefinitionFile = _context.GetMSBuildItemsWithAdditionalFiles("ApplicationDefinition").FirstOrDefault();
+
+				if (appDefinitionFile?.File.GetText()?.ToString() is { } text)
+				{
+					// Read the xml file to get the x:Class attribute on the first node
+					var appDefinitionXml = System.Xml.Linq.XDocument.Parse(text);
+					var xClassAttribute = appDefinitionXml.Root?.Attributes().FirstOrDefault(a => a.Name.LocalName == "Class");
+
+					if (xClassAttribute is not null)
+					{
+						return "global::" + xClassAttribute.Value;
+					}
+					else
+					{
+						throw new InvalidOperationException($"Unable to find an x:Class attribute on the first node of the ApplicationDefinition");
+					}
+				}
+				else
+				{
+					throw new InvalidOperationException($"Unable to find an ApplicationDefinition file");
+				}
+			}
+
+			private void TryGenerateMAUIAppDelegate(IndentedStringBuilder builder)
+			{
+				if (_mauiAppDelegate is null)
+				{
+					using (builder.BlockInvariant("namespace Microsoft.Maui"))
+					{
+						builder.AppendLineIndented("[global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]");
+						using (builder.BlockInvariant("internal class MauiUIApplicationDelegate : global::UIKit.UIApplicationDelegate"))
+						{
+						}
+					}
+				}
+			}
+		}
+
+		private class SerializationMethodsGenerator : SymbolVisitor
+		{
+			private readonly GeneratorExecutionContext _context;
+			private readonly INamedTypeSymbol? _iosViewSymbol;
+			private readonly INamedTypeSymbol? _objcNativeHandleSymbol;
+			private readonly INamedTypeSymbol? _macosViewSymbol;
+			private readonly INamedTypeSymbol? _androidViewSymbol;
+			private readonly INamedTypeSymbol? _intPtrSymbol;
+			private readonly INamedTypeSymbol? _jniHandleOwnershipSymbol;
+			private readonly INamedTypeSymbol?[]? _javaCtorParams;
+
+			public SerializationMethodsGenerator(GeneratorExecutionContext context)
+			{
+				_context = context;
+
+				_iosViewSymbol = context.Compilation.GetTypeByMetadataName("UIKit.UIView");
+				_objcNativeHandleSymbol = context.Compilation.GetTypeByMetadataName("ObjCRuntime.NativeHandle");
+				_macosViewSymbol = context.Compilation.GetTypeByMetadataName("AppKit.NSView");
+				_androidViewSymbol = context.Compilation.GetTypeByMetadataName("Android.Views.View");
+				_intPtrSymbol = context.Compilation.GetTypeByMetadataName("System.IntPtr");
+				_jniHandleOwnershipSymbol = context.Compilation.GetTypeByMetadataName("Android.Runtime.JniHandleOwnership");
+				_javaCtorParams = new[] { _intPtrSymbol, _jniHandleOwnershipSymbol };
+			}
+
+			public override void VisitNamedType(INamedTypeSymbol type)
+			{
+				_context.CancellationToken.ThrowIfCancellationRequested();
+
+				foreach (var t in type.GetTypeMembers())
+				{
+					VisitNamedType(t);
+				}
+
+				ProcessType(type);
+			}
+
+			public override void VisitModule(IModuleSymbol symbol)
+			{
+				_context.CancellationToken.ThrowIfCancellationRequested();
+
+				VisitNamespace(symbol.GlobalNamespace);
+			}
+
+			public override void VisitNamespace(INamespaceSymbol symbol)
+			{
+				_context.CancellationToken.ThrowIfCancellationRequested();
+
+				foreach (var n in symbol.GetNamespaceMembers())
+				{
+					VisitNamespace(n);
+				}
+
+				foreach (var t in symbol.GetTypeMembers())
+				{
+					VisitNamedType(t);
+				}
+			}
+
+			private void ProcessType(INamedTypeSymbol typeSymbol)
+			{
+				var isiOSView = typeSymbol.Is(_iosViewSymbol);
+				var ismacOSView = typeSymbol.Is(_macosViewSymbol);
+				var isAndroidView = typeSymbol.Is(_androidViewSymbol);
+
+				if (isiOSView || ismacOSView)
+				{
+					Func<IMethodSymbol, bool> predicate = m =>
+						!m.Parameters.IsDefaultOrEmpty
+						&& (
+							SymbolEqualityComparer.Default.Equals(m.Parameters[0].Type, _intPtrSymbol)
+							|| SymbolEqualityComparer.Default.Equals(m.Parameters[0].Type, _objcNativeHandleSymbol));
+
+					var nativeCtor = GetNativeCtor(typeSymbol, predicate, considerAllBaseTypes: false);
+
+					if (nativeCtor == null && GetNativeCtor(typeSymbol.BaseType, predicate, considerAllBaseTypes: true) != null)
+					{
+						_context.AddSource(
+							HashBuilder.BuildIDFromSymbol(typeSymbol),
+							GetGeneratedCode(typeSymbol));
+					}
+				}
+
+				if (isAndroidView)
+				{
+					Func<IMethodSymbol, bool> predicate = m => m.Parameters.Select(p => p.Type).SequenceEqual(_javaCtorParams ?? Array.Empty<ITypeSymbol?>());
+					var nativeCtor = GetNativeCtor(typeSymbol, predicate, considerAllBaseTypes: false);
+
+					if (nativeCtor == null && GetNativeCtor(typeSymbol.BaseType, predicate, considerAllBaseTypes: true) != null)
+					{
+						_context.AddSource(
+							HashBuilder.BuildIDFromSymbol(typeSymbol),
+							GetGeneratedCode(typeSymbol));
+					}
+				}
+
+				string GetGeneratedCode(INamedTypeSymbol typeSymbol)
+				{
+					var builder = new IndentedStringBuilder();
+					builder.AppendLineIndented("// <auto-generated>");
+					builder.AppendLineIndented("// *************************************************************");
+					builder.AppendLineIndented("// This file has been generated by Uno.UI (NativeCtorsGenerator)");
+					builder.AppendLineIndented("// *************************************************************");
+					builder.AppendLineIndented("// </auto-generated>");
+					builder.AppendLine();
+					builder.AppendLineIndented("using System;");
+					builder.AppendLine();
+
+					Action<IIndentedStringBuilder> beforeClassHeaderAction = builder =>
+					{
+						// These will be generated just before `partial class ClassName {`
+						builder.Append("#if __IOS__ || __MACOS__");
+						builder.AppendLine();
+						builder.AppendLineIndented("[global::Foundation.Register]");
+						builder.Append("#endif");
+						builder.AppendLine();
+					};
+
+					using (typeSymbol.AddToIndentedStringBuilder(builder, beforeClassHeaderAction))
+					{
+
+						var syntacticValidSymbolName = SyntaxFacts.GetKeywordKind(typeSymbol.Name) == SyntaxKind.None ? typeSymbol.Name : "@" + typeSymbol.Name;
+
+						if (NeedsExplicitDefaultCtor(typeSymbol))
+						{
+							builder.AppendLineIndented("/// <summary>");
+							builder.AppendLineIndented("/// Initializes a new instance of the class.");
+							builder.AppendLineIndented("/// </summary>");
+							builder.AppendLineIndented($"public {syntacticValidSymbolName}() {{ }}");
+							builder.AppendLine();
+						}
+
+						builder.Append("#if __ANDROID__");
+						builder.AppendLine();
+						builder.AppendLineIndented("/// <summary>");
+						builder.AppendLineIndented("/// Native constructor, do not use explicitly.");
+						builder.AppendLineIndented("/// </summary>");
+						builder.AppendLineIndented("/// <remarks>");
+						builder.AppendLineIndented("/// Used by the Xamarin Runtime to materialize native ");
+						builder.AppendLineIndented("/// objects that may have been collected in the managed world.");
+						builder.AppendLineIndented("/// </remarks>");
+						builder.AppendLineIndented($"public {syntacticValidSymbolName}(IntPtr javaReference, global::Android.Runtime.JniHandleOwnership transfer) : base (javaReference, transfer) {{ }}");
+						builder.Append("#endif");
+						builder.AppendLine();
+
+						builder.Append("#if __IOS__ || __MACOS__ || __MACCATALYST__");
+						builder.AppendLine();
+						builder.AppendLineIndented("/// <summary>");
+						builder.AppendLineIndented("/// Native constructor, do not use explicitly.");
+						builder.AppendLineIndented("/// </summary>");
+						builder.AppendLineIndented("/// <remarks>");
+						builder.AppendLineIndented("/// Used by the Xamarin Runtime to materialize native ");
+						builder.AppendLineIndented("/// objects that may have been collected in the managed world.");
+						builder.AppendLineIndented("/// </remarks>");
+						builder.AppendLineIndented($"public {syntacticValidSymbolName}(IntPtr handle) : base (handle) {{ }}");
+
+						if (_objcNativeHandleSymbol != null)
+						{
+							builder.AppendLineIndented("/// <summary>");
+							builder.AppendLineIndented("/// Native constructor, do not use explicitly.");
+							builder.AppendLineIndented("/// </summary>");
+							builder.AppendLineIndented("/// <remarks>");
+							builder.AppendLineIndented("/// Used by the .NET Runtime to materialize native ");
+							builder.AppendLineIndented("/// objects that may have been collected in the managed world.");
+							builder.AppendLineIndented("/// </remarks>");
+							builder.AppendLineIndented($"public {syntacticValidSymbolName}(global::ObjCRuntime.NativeHandle handle) : base (handle) {{ }}");
+						}
+
+						builder.Append("#endif");
+						builder.AppendLine();
+					}
+
+					return builder.ToString();
+				}
+
+				static IMethodSymbol? GetNativeCtor(INamedTypeSymbol? type, Func<IMethodSymbol, bool> predicate, bool considerAllBaseTypes)
+				{
+					// Consider:
+					// Type A -> Type B -> Type C
+					// HasCtor   NoCtor    NoCtor
+					// We want to generate the ctor for both Type B and Type C
+					// But since the generator doesn't guarantee Type B is getting processed first,
+					// We need to check the inheritance hierarchy.
+					// However, assume Type B wasn't declared in source, we can't generate the ctor for it.
+					// Consequently, Type C shouldn't generate source as well.
+					if (type is null)
+					{
+						return null;
+					}
+
+					var ctor = type.GetMembers(WellKnownMemberNames.InstanceConstructorName).Cast<IMethodSymbol>().FirstOrDefault(predicate);
+					if (ctor != null || !considerAllBaseTypes || !type.Locations.Any(l => l.IsInSource))
+					{
+						return ctor;
+					}
+					else
+					{
+						return GetNativeCtor(type.BaseType, predicate, true);
+					}
+				}
+			}
+
+			private static bool NeedsExplicitDefaultCtor(INamedTypeSymbol typeSymbol)
+			{
+				var hasExplicitConstructor = typeSymbol
+					.GetMembers(WellKnownMemberNames.InstanceConstructorName)
+					.Any(m => m is IMethodSymbol { IsImplicitlyDeclared: false, Parameters: { Length: 0 } });
+				if (hasExplicitConstructor)
+				{
+					return false;
+				}
+
+				var baseHasDefaultCtor = typeSymbol
+					.BaseType?
+					.GetMembers(WellKnownMemberNames.InstanceConstructorName)
+					.Any(m => m is IMethodSymbol { Parameters: { Length: 0 } }) ?? false;
+				return baseHasDefaultCtor;
+			}
+		}
+	}
+}
+