[generator] Mark Kotlin-mangled methods as non-virtual (#534)

tests/generator-Tests/Unit-Tests/KotlinFixupsTests.cs

@@ -0,0 +1,39 @@
+using System;
+using System.Linq;
+using System.Xml.Linq;
+using Java.Interop.Tools.Generator.Transformation;
+using MonoDroid.Generation;
+using NUnit.Framework;
+
+namespace generatortests
+{
+	[TestFixture]
+	public class KotlinFixupsTests
+	{
+		[Test]
+		public void CreateMethod_EnsureKotlinImplFix ()
+		{
+			var xml = XDocument.Parse ("<package name=\"com.example.test\" jni-name=\"com/example/test\"><class name=\"test\"><method name=\"add-impl\" final=\"false\" /></class></package>");
+			var klass = XmlApiImporter.CreateClass (xml.Root, xml.Root.Element ("class"));
+
+			KotlinFixups.Fixup (new [] { (GenBase)klass }.ToList ());
+
+			Assert.AreEqual ("Add", klass.Methods [0].Name);
+			Assert.IsTrue (klass.Methods [0].IsFinal);
+			Assert.IsFalse (klass.Methods [0].IsVirtual);
+		}
+
+		[Test]
+		public void CreateMethod_EnsureKotlinHashcodeFix ()
+		{
+			var xml = XDocument.Parse ("<package name=\"com.example.test\" jni-name=\"com/example/test\"><class name=\"test\"><method name=\"add-h4F1V8i\" final=\"false\" /></class></package>");
+			var klass = XmlApiImporter.CreateClass (xml.Root, xml.Root.Element ("class"));
+
+			KotlinFixups.Fixup (new [] { (GenBase) klass }.ToList ());
+
+			Assert.AreEqual ("Add", klass.Methods [0].Name);
+			Assert.IsTrue (klass.Methods [0].IsFinal);
+			Assert.IsFalse (klass.Methods [0].IsVirtual);
+		}
+	}
+}

tests/generator-Tests/Unit-Tests/XmlApiImporterTests.cs

@@ -89,24 +89,6 @@ public void CreateMethod_EnsureValidNameHyphen ()
 			Assert.AreEqual ("_3", klass.Methods [0].Name);
 		}
 
-		[Test]
-		public void CreateMethod_EnsureKotlinImplFix ()
-		{
-			var xml = XDocument.Parse ("<package name=\"com.example.test\" jni-name=\"com/example/test\"><class name=\"test\"><method name=\"add-impl\" /></class></package>");
-			var klass = XmlApiImporter.CreateClass (xml.Root, xml.Root.Element ("class"));
-
-			Assert.AreEqual ("Add", klass.Methods [0].Name);
-		}
-
-		[Test]
-		public void CreateMethod_EnsureKotlinHashcodeFix ()
-		{
-			var xml = XDocument.Parse ("<package name=\"com.example.test\" jni-name=\"com/example/test\"><class name=\"test\"><method name=\"add-h4F1V8i\" /></class></package>");
-			var klass = XmlApiImporter.CreateClass (xml.Root, xml.Root.Element ("class"));
-
-			Assert.AreEqual ("Add", klass.Methods [0].Name);
-		}
-
 		[Test]
 		public void CreateParameter_EnsureValidName ()
 		{

tools/generator/CodeGenerator.cs

@@ -12,6 +12,7 @@
 using Java.Interop.Tools.Diagnostics;
 using Java.Interop.Tools.TypeNameMappings;
 using MonoDroid.Generation.Utilities;
+using Java.Interop.Tools.Generator.Transformation;
 
 namespace Xamarin.Android.Binder
 {
@@ -149,6 +150,9 @@ static void Run (CodeGeneratorOptions options, DirectoryAssemblyResolver resolve
 					AddTypeToTable (opt, gen);
 			}
 
+			// Apply fixups
+			KotlinFixups.Fixup (gens);
+
 			Validate (gens, opt, new CodeGeneratorContext ());
 
 			if (api_versions_xml != null)

tools/generator/Java.Interop.Tools.Generator.Importers/XmlApiImporter.cs

@@ -245,25 +245,8 @@ public static Method CreateMethod (GenBase declaringType, XElement elem)
 
 			if (elem.Attribute ("managedName") != null)
 				method.Name = elem.XGetAttribute ("managedName");
-			else {
-				var name = method.JavaName;
-
-				// Kotlin generates methods that cannot be referenced in Java,
-				// like `add-impl` and `add-V5j3Lk8`. We mangle them back into
-				// something a user would expect by truncating anything after the hyphen.
-				var index = name.IndexOf ("-impl");
-
-				if (index >= 0)
-					name = name.Substring (0, index);
-
-				index = name.IndexOf ('-');
-
-				// `add-V5j3Lk8` is always a 7 character hashcode
-				if (index >= 0 && name.Length - index == 8)
-					name = name.Substring (0, index);
-
-				method.Name = StringRocks.MemberToPascalCase (name);
-			}
+			else
+				method.Name = StringRocks.MemberToPascalCase (method.JavaName);
 
 			if (method.IsReturnEnumified) {
 				method.ManagedReturn = elem.XGetAttribute ("enumReturn");

tools/generator/Java.Interop.Tools.Generator.ObjectModel/MethodBase.cs

@@ -79,6 +79,24 @@ public string GetSignature (CodeGenerationOptions opt)
 
 		public virtual bool IsGeneric => Parameters.HasGeneric;
 
+		public bool IsKotlinNameMangled {
+			get {
+				// Kotlin generates methods that cannot be referenced in Java,
+				// like `add-impl` and `add-V5j3Lk8`. We will need to fix those later.
+				if (this is Method method) {
+					if (method.JavaName.IndexOf ("-impl") >= 0)
+						return true;
+
+					var index = method.JavaName.IndexOf ('-');
+
+					// `add-V5j3Lk8` is always a 7 character hashcode
+					return index >= 0 && method.JavaName.Length - index == 8;
+				}
+
+				return false;
+			}
+		}
+
 		public virtual bool Matches (MethodBase other)
 		{
 			if (Name != other.Name)

tools/generator/Java.Interop.Tools.Generator.Transformation/KotlinFixups.cs

@@ -0,0 +1,46 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using MonoDroid.Generation;
+using MonoDroid.Utils;
+
+namespace Java.Interop.Tools.Generator.Transformation
+{
+	public static class KotlinFixups
+	{
+		public static void Fixup (List<GenBase> gens)
+		{
+			foreach (var c in gens.OfType<ClassGen> ())
+				FixupClass (c);
+		}
+
+		private static void FixupClass (ClassGen c)
+		{
+			// Kotlin mangles the name of some methods to make them
+			// inaccessible from Java, like `add-impl` and `add-V5j3Lk8`.
+			// We need to generate C# compatible names as well as prevent overriding 
+			// them as we cannot generate JCW for them.
+			var invalid_methods = c.Methods.Where (m => m.IsKotlinNameMangled).ToList ();
+
+			foreach (var method in invalid_methods) {
+
+				// If the method is virtual, mark it as !virtual as it can't be overridden in Java
+				if (!method.IsFinal)
+					method.IsFinal = true;
+
+				if (method.IsVirtual)
+					method.IsVirtual = false;
+
+				// Only run this if it's the default name (ie: not a user's "managedName")
+				if (method.Name == StringRocks.MemberToPascalCase (method.JavaName).Replace ('-', '_')) {
+					// We want to remove the hyphen and anything afterwards to fix mangled names,
+					// but a previous step converted it to an underscore. Remove the final
+					// underscore and anything after it.
+					var index = method.Name.LastIndexOf ('_');
+
+					method.Name = method.Name.Substring (0, index);
+				}
+			}
+		}
+	}
+}

tools/generator/generator.csproj

@@ -104,6 +104,7 @@
     <Compile Include="Java.Interop.Tools.Generator.ObjectModel\NamespaceMapping.cs" />
     <Compile Include="Java.Interop.Tools.Generator.ObjectModel\Parameter.cs" />
     <Compile Include="Java.Interop.Tools.Generator.ObjectModel\ParameterList.cs" />
+    <Compile Include="Java.Interop.Tools.Generator.Transformation\KotlinFixups.cs" />
     <Compile Include="Java.Interop.Tools.Generator.Transformation\Parser.cs" />
     <Compile Include="Utilities\AncestorDescendantCache.cs" />
     <Compile Include="Utilities\ProcessRocks.cs" />