[Rgen] Add support for the Methods/Constructors in the transformer.

Add the parsing of methods and constructor in the data model for the
transformer.

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

@@ -5,13 +5,19 @@
 using System.Diagnostics.CodeAnalysis;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.Macios.Generator.Attributes;
 using Microsoft.Macios.Generator.Context;
 using Microsoft.Macios.Generator.Extensions;
 
 namespace Microsoft.Macios.Generator.DataModel;
 
 readonly partial struct Constructor {
 
+	/// <summary>
+	/// The data of the export attribute used to mark the value as a property binding. 
+	/// </summary>
+	public ExportData<ObjCBindings.Constructor> ExportMethodData { get; }
+
 	public static bool TryCreate (ConstructorDeclarationSyntax declaration, RootContext context,
 		[NotNullWhen (true)] out Constructor? change)
 	{

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

@@ -30,12 +30,12 @@ namespace Microsoft.Macios.Generator.DataModel;
 	/// <summary>
 	/// Modifiers list.
 	/// </summary>
-	public ImmutableArray<SyntaxToken> Modifiers { get; } = [];
+	public ImmutableArray<SyntaxToken> Modifiers { get; init; } = [];
 
 	/// <summary>
 	/// Parameters list.
 	/// </summary>
-	public ImmutableArray<Parameter> Parameters { get; } = [];
+	public ImmutableArray<Parameter> Parameters { get; init; } = [];
 
 	public Constructor (string type,
 		SymbolAvailability symbolAvailability,
@@ -55,6 +55,8 @@ public bool Equals (Constructor other)
 	{
 		if (Type != other.Type)
 			return false;
+		if (ExportMethodData != other.ExportMethodData)
+			return false;
 		if (SymbolAvailability != other.SymbolAvailability)
 			return false;
 
@@ -110,6 +112,8 @@ public override int GetHashCode ()
 	public override string ToString ()
 	{
 		var sb = new StringBuilder ($"{{ Ctr: Type: {Type}, ");
+		sb.Append ($"ExportMethodData: {ExportMethodData}, ");
+		sb.Append ($"SymbolAvailability: {SymbolAvailability}, ");
 		sb.Append ("Attributes: [");
 		sb.AppendJoin (", ", Attributes);
 		sb.Append ("], Modifiers: [");

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

@@ -122,7 +122,7 @@ public override string ToString ()
 		sb.Append ($"ReturnType: {ReturnType}, ");
 		sb.Append ($"SymbolAvailability: {SymbolAvailability}, ");
 		sb.Append ($"ExportMethodData: {ExportMethodData}, ");
-		sb.Append ($"BindAs: {BindAs}, ");
+		sb.Append ($"BindAs: {BindAs?.ToString () ?? "null"}, ");
 		sb.Append ("Attributes: [");
 		sb.AppendJoin (", ", Attributes);
 		sb.Append ("], Modifiers: [");

src/rgen/Microsoft.Macios.Transformer/DataModel/Binding.Transformer.cs

@@ -131,10 +131,9 @@ static BindingType GetBindingType (Dictionary<string, List<AttributeData>> attri
 	/// <summary>
 	/// Retrieve the base class for a given binding based on its binding infor.
 	/// </summary>
-	/// <param name="symbol">The symbol whose base class we want to retrieve..</param>
 	/// <param name="bindingInfo">The binding information.</param>
 	/// <returns>The base class to use for the new style SDK based on the binding information.</returns>
-	static string GetBaseClass (INamedTypeSymbol symbol, BindingInfo bindingInfo)
+	static string GetBaseClass (BindingInfo bindingInfo)
 	{
 		// collecting the base class and the interface is a little more complicated in the older SDK style because
 		// we have to make the difference between a class base and a protocol base
@@ -198,6 +197,23 @@ internal static bool Skip (PropertyDeclarationSyntax propertyDeclarationSyntax,
 		return !attributes.HasExportAttribute () && !attributes.HasFieldAttribute ();
 	}
 
+	/// <summary>
+	/// Decide if a method should be ignored as a change.
+	/// </summary>
+	/// <param name="methodDeclarationSyntax">The method declaration under test.</param>
+	/// <param name="semanticModel">The semantic model of the compilation.</param>
+	/// <returns>True if the method should be skipped, false otherwise.</returns>
+	internal static bool Skip (MethodDeclarationSyntax methodDeclarationSyntax, SemanticModel semanticModel)
+	{
+		var methodSymbol = semanticModel.GetDeclaredSymbol (methodDeclarationSyntax);
+		if (methodSymbol is null)
+			// skip if we cannot retrieve the symbol
+			return true;
+		var attributes = methodSymbol.GetAttributeData ();
+		// we will skip methods that do not have the export attribute
+		return !attributes.HasExportAttribute ();
+	}
+
 	/// <summary>
 	/// Create a new binding based on the interface declaration. Because in the old SDK old the bindings
 	/// are represented by an interface, this constructor will ensure that the correct binding type is set.
@@ -216,7 +232,7 @@ internal Binding (InterfaceDeclarationSyntax interfaceDeclarationSyntax, INamedT
 		name = symbol.Name;
 		availability = symbol.GetAvailabilityForSymbol ();
 		namespaces = symbol.GetNamespaceArray ();
-		baseClass = GetBaseClass (symbol, BindingInfo);
+		baseClass = GetBaseClass (BindingInfo);
 
 		// retrieve the interfaces and protocols, notice that this are two out params
 		GetInterfaceAndProtocols (symbol, out interfaces, out protocols);
@@ -234,6 +250,17 @@ internal Binding (InterfaceDeclarationSyntax interfaceDeclarationSyntax, INamedT
 		// loop over the different members and add them to the model
 		GetMembers<PropertyDeclarationSyntax, Property> (interfaceDeclarationSyntax, context, Skip, Property.TryCreate,
 			out properties);
+		// methods are a little diff, in the old SDK style, both methods and constructors are methods, we will get
+		// all exported methods and then filter accordingly
+		GetMembers<MethodDeclarationSyntax, Method> (interfaceDeclarationSyntax, context, Skip, Method.TryCreate,
+			out ImmutableArray<Method> allMethods);
+		methods = [.. allMethods.Where (m => !m.IsConstructor)];
+		constructors = allMethods.Where (m => m.IsConstructor)
+			.Select (m => m.ToConstructor ())
+			.Where (c => c is not null)
+			.Select (c => c!.Value)
+			.ToImmutableArray ();
+
 	}
 
 	/// <inheritdoc/>

src/rgen/Microsoft.Macios.Transformer/DataModel/Constructor.Transformer.cs

@@ -4,12 +4,36 @@
 using System.Collections.Immutable;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.Macios.Generator.Availability;
+using Microsoft.Macios.Transformer.Attributes;
 using static Microsoft.CodeAnalysis.CSharp.SyntaxFactory;
 
 namespace Microsoft.Macios.Generator.DataModel;
 
 readonly partial struct Constructor {
 
+	readonly ExportData? overrideExportData;
+
+	/// <summary>
+	/// The data of the export attribute used to mark the value as a property binding. 
+	/// </summary>
+	public ExportData? ExportMethodData {
+		get => overrideExportData ?? ExportAttribute;
+		init => overrideExportData = value;
+	}
+
+	public Constructor (string type,
+		SymbolAvailability symbolAvailability,
+		Dictionary<string, List<AttributeData>> attributes,
+		ImmutableArray<Parameter> parameters)
+	{
+		Type = type;
+		SymbolAvailability = symbolAvailability;
+		Attributes = [];
+		AttributesDictionary = attributes;
+		Parameters = parameters;
+		ExportMethodData = null;
+	}
 
 	/// <summary>
 	/// Create a constructor from a method signature.
@@ -22,6 +46,7 @@ public Constructor (in Method method)
 		Attributes = method.Attributes;
 		Parameters = method.Parameters;
 		AttributesDictionary = method.AttributesDictionary;
+		ExportMethodData = method.ExportMethodData;
 
 		// modifiers cannot only be copied, we do not have a virtual/override constructor, it is either
 		// public, private or internal.