[RGen] Remove all the Nullable<Method> boxing that happens in the generator (#23431)

Author: mandel-macaque

src/rgen/Microsoft.Macios.Generator/DataModel/Method.Generator.cs

@@ -100,7 +100,7 @@ public Method (string type, string name, TypeInfo returnType,
 		ExportData<ObjCBindings.Method> exportMethodData,
 		ImmutableArray<AttributeCodeChange> attributes,
 		ImmutableArray<SyntaxToken> modifiers,
-		ImmutableArray<Parameter> parameters)
+		ImmutableArray<Parameter> parameters) : this (StructState.Initialized)
 	{
 		Type = type;
 		Name = name;

src/rgen/Microsoft.Macios.Generator/DataModel/Method.cs

@@ -15,15 +15,30 @@ namespace Microsoft.Macios.Generator.DataModel;
 [StructLayout (LayoutKind.Auto)]
 readonly partial struct Method : IEquatable<Method> {
 
+	/// <summary>
+	/// The initialization state of the struct.
+	/// </summary>
+	StructState State { get; init; } = StructState.Default;
+
+	/// <summary>
+	/// Gets the default, uninitialized instance of <see cref="Method"/>.
+	/// </summary>
+	public static Method Default { get; } = new (StructState.Default);
+
+	/// <summary>
+	/// Gets a value indicating whether the instance is the default, uninitialized instance.
+	/// </summary>
+	public bool IsNullOrDefault => State == StructState.Default;
+
 	/// <summary>
 	/// Type name that owns the method.
 	/// </summary>
-	public string Type { get; }
+	public string Type { get; } = string.Empty;
 
 	/// <summary>
 	/// Method name.
 	/// </summary>
-	public string Name { get; init; }
+	public string Name { get; init; } = string.Empty;
 
 	/// <summary>
 	/// True if the method is an extension method.
@@ -74,9 +89,16 @@ public ImmutableArray<SyntaxToken> Modifiers {
 	/// </summary>
 	public ImmutableArray<Parameter> Parameters { get; init; } = [];
 
+	internal Method (StructState state)
+	{
+		State = state;
+	}
+
 	/// <inheritdoc/>
 	public bool Equals (Method other)
 	{
+		if (State == StructState.Default && other.State == StructState.Default)
+			return true;
 		if (Type != other.Type)
 			return false;
 		if (Name != other.Name)

src/rgen/Microsoft.Macios.Generator/DataModel/Property.Generator.cs

@@ -322,13 +322,13 @@ public Property ToStrongDelegate ()
 	/// </summary>
 	/// <param name="typeInfo">The type information for the 'this' parameter of the extension methods.</param>
 	/// <returns>A tuple containing the getter method and an optional setter method (null if the property is read-only).</returns>
-	public (Method? Getter, Method? Setter) ToExtensionMethods (TypeInfo typeInfo)
+	public (Method Getter, Method Setter) ToExtensionMethods (TypeInfo typeInfo)
 	{
 		// create the parameter with the provided type info
 		var thisParameter = new Parameter (0, typeInfo, "self") { IsThis = true, };
 
 		var getter = GetAccessor (AccessorKind.Getter);
-		Method? getterMethod = null;
+		Method getterMethod = Method.Default;
 		if (!getter.IsNullOrDefault)
 			getterMethod = new Method (
 				type: typeInfo.FullyQualifiedName,
@@ -337,13 +337,16 @@ public Property ToStrongDelegate ()
 				symbolAvailability: getter.SymbolAvailability,
 				exportMethodData: new (getter.GetSelector (this)),
 				attributes: [],
-				modifiers: [Token (SyntaxKind.InternalKeyword), Token (SyntaxKind.StaticKeyword)],
+				modifiers: [
+					Token (SyntaxKind.InternalKeyword).WithTrailingTrivia (Space),
+					Token (SyntaxKind.StaticKeyword).WithTrailingTrivia (Space)
+				],
 				parameters: [thisParameter]) {
 				BindAs = BindAs // return bindas is the same as the property bindas
 			};
 
 		var setter = GetAccessor (AccessorKind.Setter);
-		Method? setterMethod = null;
+		Method setterMethod = Method.Default;
 		if (!setter.IsNullOrDefault) {
 			// we need a second parameter for the setter
 			var valueParameter = new Parameter (1, ReturnType, "value") {
@@ -356,7 +359,10 @@ public Property ToStrongDelegate ()
 				symbolAvailability: setter.SymbolAvailability,
 				exportMethodData: new (setter.GetSelector (this)),
 				attributes: [],
-				modifiers: [Token (SyntaxKind.InternalKeyword), Token (SyntaxKind.StaticKeyword)],
+				modifiers: [
+					Token (SyntaxKind.InternalKeyword).WithTrailingTrivia (Space),
+					Token (SyntaxKind.StaticKeyword).WithTrailingTrivia (Space)
+				],
 				parameters: [thisParameter, valueParameter]);
 		}
 		return (getterMethod, setterMethod);

src/rgen/Microsoft.Macios.Generator/Emitters/BindingSyntaxFactory.KnownTypes.cs

@@ -181,6 +181,13 @@ static partial class BindingSyntaxFactory {
 		@namespace: ["Foundation"],
 		@class: "NSMutableDictionary");
 
+	/// <summary>
+	/// TypeSyntax for Foundation.RequiredMember.
+	/// </summary>
+	public static readonly TypeSyntax RequiredMember = StringExtensions.GetIdentifierName (
+		@namespace: ["Foundation"],
+		@class: "RequiredMember");
+
 	// CoreMedia types
 
 	/// <summary>

src/rgen/Microsoft.Macios.Generator/Emitters/ProtocolEmitter.cs

@@ -9,6 +9,7 @@
 using Microsoft.Macios.Generator.Attributes;
 using Microsoft.Macios.Generator.Context;
 using Microsoft.Macios.Generator.DataModel;
+using Microsoft.Macios.Generator.Formatters;
 using Microsoft.Macios.Generator.IO;
 using ObjCBindings;
 using static Microsoft.Macios.Generator.Emitters.BindingSyntaxFactory;
@@ -21,7 +22,7 @@ namespace Microsoft.Macios.Generator.Emitters;
 /// Emitter responsible for generating protocol interfaces.
 /// Generates C# interfaces that represent Objective-C protocols with proper protocol member attributes.
 /// </summary>
-class ProtocolEmitter : ICodeEmitter {
+class ProtocolEmitter : IClassEmitter {
 	/// <inheritdoc />
 	public string GetSymbolName (in Binding binding) => binding.Name;
 
@@ -49,17 +50,65 @@ void EmitDefaultConstructors (in BindingContext bindingContext, TabbedWriter<Str
 ");
 	}
 
+	/// <summary>
+	/// Emits the properties for the protocol interface, including their getter and setter methods.
+	/// </summary>
+	/// <param name="context">The binding context containing protocol information.</param>
+	/// <param name="properties">A collection of properties to emit, along with their getter and setter methods.</param>
+	/// <param name="classBlock">The writer for the class block.</param>
+	void EmitProperties (in BindingContext context, in ImmutableArray<(Property Property, Method Getter, Method Setter)> properties, TabbedWriter<StringWriter> classBlock)
+	{
+		var uiThreadCheck = (context.NeedsThreadChecks)
+			? EnsureUiThread (context.RootContext.CurrentPlatform)
+			: null;
+		foreach (var (property, getter, setter) in properties) {
+			// protocol properties are emitted in the following format:
+			// - _GetFoo method if the property has a getter
+			// - _SetFoo method if the property has a setter
+			// - Foo property that uses the getter/setter methods
+
+			if (!getter.IsNullOrDefault) {
+				this.EmitMethod (context, getter, classBlock, uiThreadCheck);
+			}
+
+			if (!setter.IsNullOrDefault) {
+				this.EmitMethod (context, setter, classBlock, uiThreadCheck);
+			}
+
+			// write the property declarations
+			classBlock.WriteLine ();
+			classBlock.AppendMemberAvailability (property.SymbolAvailability);
+			classBlock.AppendGeneratedCodeAttribute (optimizable: true);
+			if (!property.IsOptional) {
+				classBlock.AppendRequiredMemberAttribute ();
+			}
+			using (var propertyBlock = classBlock.CreateBlock (property.ToDeclaration ().ToString (), block: true)) {
+				// we do not need to get the property accessors since we already have the getters/setters, we can
+				// decide what needs to be added based on those methods
+				if (!getter.IsNullOrDefault) {
+					propertyBlock.AppendMemberAvailability (getter.SymbolAvailability);
+					propertyBlock.WriteLine ($"get => {getter.Name} (this);");
+				}
+
+				if (!setter.IsNullOrDefault) {
+					propertyBlock.AppendMemberAvailability (setter.SymbolAvailability);
+					propertyBlock.WriteLine ($"set => {setter.Name} (this, value);");
+				}
+			}
+		}
+	}
+
 	/// <summary>
 	/// Gets the properties from the binding context and their corresponding extension methods.
 	/// Returns a collection of tuples containing the property and its optional getter/setter methods.
 	/// </summary>
 	/// <param name="bindingContext">The binding context containing the properties.</param>
 	/// <returns>An immutable array of tuples containing properties and their extension methods.</returns>
-	static ImmutableArray<(Property Property, Method? Getter, Method? Setter)> GetProperties (in BindingContext bindingContext)
+	static ImmutableArray<(Property Property, Method Getter, Method Setter)> CreatePropertyExtensionMethods (in BindingContext bindingContext)
 	{
 		// collect all properties and generate the extension methods, this will be used to generate the protocol
 		// member data and later the extension methods.
-		var propertiesBucket = ImmutableArray.CreateBuilder<(Property Property, Method? Getter, Method? Setter)> (bindingContext.Changes.Properties.Length);
+		var propertiesBucket = ImmutableArray.CreateBuilder<(Property Property, Method Getter, Method Setter)> (bindingContext.Changes.Properties.Length);
 		foreach (var property in bindingContext.Changes.Properties.OrderBy (p => p.Name)) {
 			var (getter, setter) = property.ToExtensionMethods (new (bindingContext.Changes.Name, SpecialType.None));
 			propertiesBucket.Add ((property, getter, setter));
@@ -95,7 +144,7 @@ public bool TryEmit (in BindingContext bindingContext, [NotNullWhen (false)] out
 
 			// we need to collect the properties extension methods, we do that with a helper method
 			// that will return the properties and their getters/setters.
-			var properties = GetProperties (bindingContext);
+			var properties = CreatePropertyExtensionMethods (bindingContext);
 
 			// append the properties to the protocol member data
 			foreach (var (property, getter, setter) in properties) {
@@ -113,6 +162,9 @@ public bool TryEmit (in BindingContext bindingContext, [NotNullWhen (false)] out
 
 				// emit static constructor
 				EmitDefaultConstructors (in bindingContext, interfaceBlock);
+
+				// emit the properties, this will generate the getters/setters and the properties themselves
+				EmitProperties (in bindingContext, in properties, interfaceBlock);
 			}
 		}
 		return true;

src/rgen/Microsoft.Macios.Generator/Formatters/TypeInfoFormatter.cs

@@ -22,6 +22,9 @@ public static TypeSyntax GetIdentifierSyntax (this in TypeInfo typeInfo)
 		TypeSyntax classSyntax;
 		// the type info already provides the correct name, but we need to build the actual class for arrays and 
 		// generic types
+		if (typeInfo.IsVoid) {
+			return IdentifierName ("void");
+		}
 		if (typeInfo.IsArray) {
 			// could be a params array or simply an array
 			classSyntax = ArrayType (IdentifierName (typeInfo.Name))

src/rgen/Microsoft.Macios.Generator/IO/TabbedStringBuilderExtensions.cs

@@ -221,4 +221,16 @@ public static TabbedWriter<StringWriter> AppendProtocolAttribute (this TabbedWri
 		self.WriteLine ($"[Protocol (Name = \"{name}\", WrapperType = typeof ({wrapperName}))]");
 		return self;
 	}
+
+	/// <summary>
+	/// Appends a `[Foundation.RequiredMember]` attribute to the current writer.
+	/// This attribute is used to mark a member as required.
+	/// </summary>
+	/// <param name="self">A tabbed string writer.</param>
+	/// <returns>The current writer.</returns>
+	public static TabbedWriter<StringWriter> AppendRequiredMemberAttribute (this TabbedWriter<StringWriter> self)
+	{
+		self.WriteLine ($"[{RequiredMember}]");
+		return self;
+	}
 }

tests/rgen/Microsoft.Macios.Generator.Tests/DataModel/PropertyTests/FromDeclarationTests.cs

@@ -1147,7 +1147,7 @@ public class TestClass {
 						},
 					]
 				),
-				null!
+				Method.Default,
 			];
 
 			const string getterSetter = @"
@@ -1331,7 +1331,7 @@ IEnumerator IEnumerable.GetEnumerator ()
 
 	[Theory]
 	[AllSupportedPlatformsClassData<TestDataToExtensionMethods>]
-	void ToExtensionMethods (ApplePlatform platform, string inputText, TypeInfo protocolType, Method? expectedGetter, Method? expectedSetter)
+	void ToExtensionMethods (ApplePlatform platform, string inputText, TypeInfo protocolType, Method expectedGetter, Method expectedSetter)
 	{
 		var (compilation, syntaxTrees) = CreateCompilation (platform, sources: inputText);
 		Assert.Single (syntaxTrees);
@@ -1343,20 +1343,20 @@ void ToExtensionMethods (ApplePlatform platform, string inputText, TypeInfo prot
 		Assert.True (Property.TryCreate (declaration, semanticModel, out var changes));
 		Assert.NotNull (changes);
 		var (getter, setter) = changes.Value.ToExtensionMethods (protocolType);
-		if (expectedGetter is null) {
-			Assert.Null (getter);
+		if (expectedGetter.IsNullOrDefault) {
+			Assert.True (getter.IsNullOrDefault);
 		} else {
-			Assert.NotNull (getter);
-			Assert.True (getter.Value.IsExtension);
-			Assert.Equal (expectedGetter.Value, getter.Value);
+			Assert.False (getter.IsNullOrDefault);
+			Assert.True (getter.IsExtension);
+			Assert.Equal (expectedGetter, getter);
 		}
 
-		if (expectedSetter is null) {
-			Assert.Null (setter);
+		if (expectedSetter.IsNullOrDefault) {
+			Assert.True (setter.IsNullOrDefault);
 		} else {
-			Assert.NotNull (setter);
-			Assert.True (setter.Value.IsExtension);
-			Assert.Equal (expectedSetter.Value, setter.Value);
+			Assert.False (setter.IsNullOrDefault);
+			Assert.True (setter.IsExtension);
+			Assert.Equal (expectedSetter, setter);
 		}
 	}
 }

tests/rgen/Microsoft.Macios.Generator.Tests/IO/TabbedStringBuilderTests.cs

@@ -336,6 +336,22 @@ public void AppendProtocolAttributeTests (string name, string wrapperName, int t
 		Assert.Equal (expected, result);
 	}
 
+	[Theory]
+	[InlineData (0, "")]
+	[InlineData (1, "\t")]
+	[InlineData (5, "\t\t\t\t\t")]
+	public void AppendRequiredMemberAttributeTests (int tabCount, string expectedTabs)
+	{
+		var expected = $"{expectedTabs}[global::Foundation.RequiredMember]\n";
+		string result;
+		using (var block = new TabbedStringBuilder (sb, tabCount)) {
+			block.AppendRequiredMemberAttribute ();
+			result = block.ToCode ();
+		}
+
+		Assert.Equal (expected, result);
+	}
+
 	[Theory]
 	[InlineData (0, "")]
 	[InlineData (1, "\t")]
@@ -618,7 +634,7 @@ public static IEnumerable<object []> AppendProtocolMemberDataTestData {
 					ReturnTypeDelegateProxy = null,
 					ParameterBlockProxy = [null],
 				},
-				"[ProtocolMember (IsRequired = true, IsProperty = false, IsStatic = false, Name = \"MyMethod\", Selector = \"completeRequestReturningItems:completionHandler:\", ReturnType = typeof (global::System.void), ParameterType = new Type [] { typeof (string) }, ParameterByRef = new bool [] { false }, ParameterBlockProxy = new Type? [] { null })]\n"
+				"[ProtocolMember (IsRequired = true, IsProperty = false, IsStatic = false, Name = \"MyMethod\", Selector = \"completeRequestReturningItems:completionHandler:\", ReturnType = typeof (void), ParameterType = new Type [] { typeof (string) }, ParameterByRef = new bool [] { false }, ParameterBlockProxy = new Type? [] { null })]\n"
 			];
 
 			yield return [
@@ -635,7 +651,7 @@ public static IEnumerable<object []> AppendProtocolMemberDataTestData {
 					ReturnTypeDelegateProxy = null,
 					ParameterBlockProxy = [null],
 				},
-				"[ProtocolMember (IsRequired = true, IsProperty = false, IsStatic = true, Name = \"MyMethod\", Selector = \"completeRequestReturningItems:completionHandler:\", ReturnType = typeof (global::System.void), ParameterType = new Type [] { typeof (string) }, ParameterByRef = new bool [] { false }, ParameterBlockProxy = new Type? [] { null })]\n"
+				"[ProtocolMember (IsRequired = true, IsProperty = false, IsStatic = true, Name = \"MyMethod\", Selector = \"completeRequestReturningItems:completionHandler:\", ReturnType = typeof (void), ParameterType = new Type [] { typeof (string) }, ParameterByRef = new bool [] { false }, ParameterBlockProxy = new Type? [] { null })]\n"
 			];
 
 			yield return [
@@ -721,7 +737,7 @@ public static IEnumerable<object []> AppendProtocolMemberDataTestData {
 					ParameterBlockProxy = [null],
 					IsVariadic = true,
 				},
-				"[ProtocolMember (IsRequired = true, IsProperty = false, IsStatic = false, Name = \"MyMethod\", Selector = \"completeRequestReturningItems:completionHandler:\", ReturnType = typeof (global::System.void), ParameterType = new Type [] { typeof (string) }, ParameterByRef = new bool [] { false }, ParameterBlockProxy = new Type? [] { null })]\n"
+				"[ProtocolMember (IsRequired = true, IsProperty = false, IsStatic = false, Name = \"MyMethod\", Selector = \"completeRequestReturningItems:completionHandler:\", ReturnType = typeof (void), ParameterType = new Type [] { typeof (string) }, ParameterByRef = new bool [] { false }, ParameterBlockProxy = new Type? [] { null })]\n"
 			];
 
 			yield return [
@@ -773,7 +789,7 @@ public static IEnumerable<object []> AppendProtocolMemberDataTestData {
 					ParameterBlockProxy = [null],
 					IsVariadic = false,
 				},
-				"[ProtocolMember (IsRequired = false, IsProperty = false, IsStatic = false, Name = \"MyMethod\", Selector = \"completeRequestReturningItems:completionHandler:\", ReturnType = typeof (global::System.void), ParameterType = new Type [] { typeof (string) }, ParameterByRef = new bool [] { false }, ParameterBlockProxy = new Type? [] { null })]\n"
+				"[ProtocolMember (IsRequired = false, IsProperty = false, IsStatic = false, Name = \"MyMethod\", Selector = \"completeRequestReturningItems:completionHandler:\", ReturnType = typeof (void), ParameterType = new Type [] { typeof (string) }, ParameterByRef = new bool [] { false }, ParameterBlockProxy = new Type? [] { null })]\n"
 			];
 		}
 	}