gistfile0.txt

diff --git a/src/rgen/Microsoft.Macios.Generator/DataModel/CodeChanges.cs b/src/rgen/Microsoft.Macios.Generator/DataModel/CodeChanges.cs
index dc16fb990..1f0a40a96 100644
--- a/src/rgen/Microsoft.Macios.Generator/DataModel/CodeChanges.cs
+++ b/src/rgen/Microsoft.Macios.Generator/DataModel/CodeChanges.cs
@@ -1,4 +1,6 @@
+using System;
 using System.Collections.Immutable;
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp;
@@ -110,6 +112,7 @@ readonly struct CodeChanges {
 		if (methodDeclarationSyntax.Modifiers.Any (SyntaxKind.PartialKeyword)) {
 			return !methodDeclarationSyntax.HasAttribute (semanticModel, AttributesNames.ExportMethodAttribute);
 		}
+
 		return true;
 	}
 
@@ -145,12 +148,34 @@ readonly struct CodeChanges {
 				continue;
 			var memberName = val.Identifier.ToFullString ().Trim ();
 			var attributes = val.GetAttributeCodeChanges (semanticModel);
-			bucket.Add (new (memberName, attributes));
+			bucket.Add (new(memberName, attributes));
 		}
 
 		EnumMembers = bucket.ToImmutable ();
 	}
 
+	delegate bool SkipDelegate<T> (T declarationSyntax, SemanticModel semanticModel);
+
+	delegate bool TryCreateDelegate<in T, TR> (T declaration, SemanticModel semanticModel,
+		[NotNullWhen (true)] out TR? change)
+		where T : MemberDeclarationSyntax
+		where TR : struct;
+
+	ImmutableArray<TR> GetMembers<T, TR> (TypeDeclarationSyntax baseDeclarationSyntax, SemanticModel semanticModel,
+		SkipDelegate<T> skip, TryCreateDelegate<T, TR> tryCreate) where T : MemberDeclarationSyntax where TR : struct
+	{
+		var bucket = ImmutableArray.CreateBuilder<TR> ();
+		var declarations = baseDeclarationSyntax.Members.OfType<T> ();
+		foreach (var declaration in declarations) {
+			if (skip (declaration, semanticModel))
+				continue;
+			if (tryCreate (declaration, semanticModel, out var change))
+				bucket.Add (change.Value);
+		}
+
+		return bucket.ToImmutable ();
+	}
+
 	/// <summary>
 	/// Creates a new instance of the <see cref="CodeChanges"/> struct for a given class declaration.
 	/// </summary>
@@ -161,50 +186,11 @@ readonly struct CodeChanges {
 		FullyQualifiedSymbol = classDeclaration.GetFullyQualifiedIdentifier ();
 		SymbolDeclaration = classDeclaration;
 		EnumMembers = []; // always empty since classes dot not have enum values
-		Attributes = [];
-
-		var properties = ImmutableArray.CreateBuilder<Property> ();
-		var propertyDeclarations = classDeclaration.Members.OfType<PropertyDeclarationSyntax> ();
-		foreach (var declaration in propertyDeclarations) {
-			if (Skip (declaration, semanticModel))
-				continue;
-			if (Property.TryCreate (declaration, semanticModel, out var change))
-				properties.Add (change.Value);
-		}
-
-		Properties = properties.ToImmutable ();
-
-		var constructors = ImmutableArray.CreateBuilder<Constructor> ();
-		var constructorDeclarations = classDeclaration.Members.OfType<ConstructorDeclarationSyntax> ();
-		foreach (var declaration in constructorDeclarations) {
-			if (Skip (declaration, semanticModel))
-				continue;
-			if (Constructor.TryCreate (declaration, semanticModel, out var change))
-				constructors.Add (change.Value);
-		}
-
-		Constructors = constructors.ToImmutable ();
-
-		var events = ImmutableArray.CreateBuilder<Event> ();
-		var eventDeclarations = classDeclaration.Members.OfType<EventDeclarationSyntax> ();
-		foreach (var declaration in eventDeclarations) {
-			if (Skip (declaration, semanticModel))
-				continue;
-			if (Event.TryCreate (declaration, semanticModel, out var change))
-				events.Add (change.Value);
-		}
-
-		Events = events.ToImmutable ();
-
-		var methods = ImmutableArray.CreateBuilder<Method> ();
-		var methodDeclarations = classDeclaration.Members.OfType<MethodDeclarationSyntax> ();
-		foreach (MethodDeclarationSyntax declaration in methodDeclarations) {
-			if (Skip (declaration, semanticModel))
-				continue;
-			if (Method.TryCreate (declaration, semanticModel, out var change))
-				methods.Add (change.Value);
-		}
-		Methods = methods.ToImmutable ();
+		Attributes = classDeclaration.GetAttributeCodeChanges (semanticModel);
+		Constructors = GetMembers<ConstructorDeclarationSyntax, Constructor> (classDeclaration, semanticModel, Skip, Constructor.TryCreate);
+		Properties = GetMembers<PropertyDeclarationSyntax, Property> (classDeclaration, semanticModel, Skip, Property.TryCreate);
+		Events = GetMembers<EventDeclarationSyntax, Event> (classDeclaration, semanticModel, Skip, Event.TryCreate);
+		Methods = GetMembers<MethodDeclarationSyntax, Method> (classDeclaration, semanticModel, Skip, Method.TryCreate);
 	}
 
 	/// <summary>
@@ -216,9 +202,11 @@ readonly struct CodeChanges {
 	{
 		FullyQualifiedSymbol = interfaceDeclaration.GetFullyQualifiedIdentifier ();
 		SymbolDeclaration = interfaceDeclaration;
-		// TODO: to be implemented once we add protocol support
-		EnumMembers = [];
-		Attributes = [];
+		Attributes = interfaceDeclaration.GetAttributeCodeChanges (semanticModel);
+		Constructors = []; // interfaces do not list constructors
+		Properties = GetMembers<PropertyDeclarationSyntax, Property> (interfaceDeclaration, semanticModel, Skip, Property.TryCreate);
+		Events = GetMembers<EventDeclarationSyntax, Event> (interfaceDeclaration, semanticModel, Skip, Event.TryCreate);
+		Methods = GetMembers<MethodDeclarationSyntax, Method> (interfaceDeclaration, semanticModel, Skip, Method.TryCreate);
 	}
 
 	/// <summary>