[Java.Interop] Add JniTypeSignatureAttribute.InvokerType (#1284)

Context: #1263
Context: #1263 (comment)

We want the default trimmer infrastructure to be able to automatically
preserve the `*Invoker` types which are required for interacting with
`abstract` classes and interfaces.

The most straightforward way to do this is to add a new `InvokerType`
property to `JniTypeSignatureAttribute` (and eventually
`RegisterAttribute`):

	partial class JniTypeSignatureAttribute {
	    [DynamicallyAccessedMembers (DynamicallyAccessedMemberTypes.PublicConstructors |
	        DynamicallyAccessedMemberTypes.NonPublicConstructors)]
	    public Type? InvokerType {get; set;}
	}

Update `generator` so that `generator --codegen-target=JavaInterop1`
output sets this new property on abstract classes and interfaces:

	namespace Java.Lang {

	    [Java.Interop.JniTypeSignatureAttribute("java/lang/Runnable", GenerateJavaPeer=false, InvokerType=typeof(Java.Lang.IRunnableInvoker))]
	    public partial interface IRunnable {
	    }
	    internal partial class IRunnableInvoker {
	    }

	    [Java.Interop.JniTypeSignatureAttribute("java/lang/Number", GenerateJavaPeer=false, InvokerType=typeof(Java.Lang.NumberInvoker))]
	    public abstract partial class Number {
	    }
	    internal partial class NumberInvoker {
	    }
	}

This allows the default trimmer to automatically preserve the
`*Invoker` type and constructors.

Update `Java.Interop.JniRuntime.JniValueManager` to no longer look
for `*Invoker` types "by string", and instead require use of the
`JniTypeSignatureAttribute.InvokerType` property.

Update unit tests and expected output so that everything works.

Author: jonpryor

src/Java.Base-ref.cs

@@ -386,18 +386,9 @@ static Type GetPeerType ([DynamicallyAccessedMembers (Constructors)] Type type)
 			[return: DynamicallyAccessedMembers (Constructors)]
 			static Type? GetInvokerType (Type type)
 			{
-				const string suffix = "Invoker";
-
 				// https://github.com/xamarin/xamarin-android/blob/5472eec991cc075e4b0c09cd98a2331fb93aa0f3/src/Microsoft.Android.Sdk.ILLink/MarkJavaObjects.cs#L176-L186
-				const string assemblyGetTypeMessage = "'Invoker' types are preserved by the MarkJavaObjects trimmer step.";
 				const string makeGenericTypeMessage = "Generic 'Invoker' types are preserved by the MarkJavaObjects trimmer step.";
 
-				[UnconditionalSuppressMessage ("Trimming", "IL2026", Justification = assemblyGetTypeMessage)]
-				[UnconditionalSuppressMessage ("Trimming", "IL2073", Justification = assemblyGetTypeMessage)]
-				[return: DynamicallyAccessedMembers (Constructors)]
-				static Type? AssemblyGetType (Assembly assembly, string typeName) =>
-					assembly.GetType (typeName);
-
 				[UnconditionalSuppressMessage ("Trimming", "IL2055", Justification = makeGenericTypeMessage)]
 				[return: DynamicallyAccessedMembers (Constructors)]
 				static Type MakeGenericType (
@@ -409,18 +400,16 @@ static Type MakeGenericType (
 					type.MakeGenericType (arguments);
 					#pragma warning restore IL3050
 
+				var signature   = type.GetCustomAttribute<JniTypeSignatureAttribute> ();
+				if (signature == null || signature.InvokerType == null) {
+					return null;
+				}
+
 				Type[] arguments = type.GetGenericArguments ();
 				if (arguments.Length == 0)
-					return AssemblyGetType (type.Assembly, type + suffix);
-				Type definition = type.GetGenericTypeDefinition ();
-				int bt = definition.FullName!.IndexOf ("`", StringComparison.Ordinal);
-				if (bt == -1)
-					throw new NotSupportedException ("Generic type doesn't follow generic type naming convention! " + type.FullName);
-				Type? suffixDefinition = AssemblyGetType (definition.Assembly,
-						definition.FullName.Substring (0, bt) + suffix + definition.FullName.Substring (bt));
-				if (suffixDefinition == null)
-					return null;
-				return MakeGenericType (suffixDefinition, arguments);
+					return signature.InvokerType;
+
+				return MakeGenericType (signature.InvokerType, arguments);
 			}
 
 			public object? CreateValue (

src/Java.Interop/Java.Interop/JniRuntime.JniValueManager.cs

@@ -1,6 +1,7 @@
 #nullable enable
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 
 namespace Java.Interop
 {
@@ -31,6 +32,9 @@ public      int         ArrayRank               {
 		}
 
 		public      bool        GenerateJavaPeer        {get; set;}
+
+		[DynamicallyAccessedMembers (DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors)]
+		public      Type?       InvokerType             {get; set;}
 	}
 }
 

src/Java.Interop/Java.Interop/JniTypeSignatureAttribute.cs

@@ -3,3 +3,5 @@ static Java.Interop.JniEnvironment.BeginMarshalMethod(nint jnienv, out Java.Inte
 static Java.Interop.JniEnvironment.EndMarshalMethod(ref Java.Interop.JniTransition transition) -> void
 virtual Java.Interop.JniRuntime.OnEnterMarshalMethod() -> void
 virtual Java.Interop.JniRuntime.OnUserUnhandledException(ref Java.Interop.JniTransition transition, System.Exception! e) -> void
+Java.Interop.JniTypeSignatureAttribute.InvokerType.get -> System.Type?
+Java.Interop.JniTypeSignatureAttribute.InvokerType.set -> void

src/Java.Interop/PublicAPI.Unshipped.txt

@@ -80,7 +80,7 @@ public unsafe MyJavaInterfaceImpl ()
 	}
 }
 
-[JniTypeSignature (JniTypeName, GenerateJavaPeer=false)]
+[JniTypeSignature (JniTypeName, GenerateJavaPeer=false, InvokerType=typeof(IJavaInterfaceInvoker))]
 interface IJavaInterface : IJavaPeerable {
 	internal            const       string          JniTypeName    = "net/dot/jni/test/JavaInterface";
 

tests/Java.Interop-Tests/Java.Interop/JavaPeerableExtensionsTests.cs

@@ -1,5 +1,5 @@
 // Metadata.xml XPath interface reference: path="/api/package[@name='java.code']/interface[@name='AnimatorListener']"
-[global::Java.Interop.JniTypeSignature ("java/code/AnimatorListener", GenerateJavaPeer=false)]
+[global::Java.Interop.JniTypeSignature ("java/code/AnimatorListener", GenerateJavaPeer=false, InvokerType=typeof (java.code.AnimatorListenerInvoker))]
 public partial interface AnimatorListener : IJavaPeerable {
 	// Metadata.xml XPath method reference: path="/api/package[@name='java.code']/interface[@name='AnimatorListener']/method[@name='OnAnimationEnd' and count(parameter)=1 and parameter[1][@type='int']]"
 	[global::Java.Interop.JniMethodSignature ("OnAnimationEnd", "(I)Z")]

tests/generator-Tests/Unit-Tests/CodeGeneratorExpectedResults/JavaInterop1/WriteDuplicateInterfaceEventArgs.txt

@@ -1,5 +1,5 @@
 // Metadata.xml XPath interface reference: path="/api/package[@name='java.code']/interface[@name='IMyInterface']"
-[global::Java.Interop.JniTypeSignature ("java/code/IMyInterface", GenerateJavaPeer=false)]
+[global::Java.Interop.JniTypeSignature ("java/code/IMyInterface", GenerateJavaPeer=false, InvokerType=typeof (java.code.IMyInterfaceInvoker))]
 public partial interface IMyInterface : IJavaPeerable {
 	private static readonly JniPeerMembers _members = new JniPeerMembers ("java/code/IMyInterface", typeof (IMyInterface), isInterface: true);
 

tests/generator-Tests/Unit-Tests/CodeGeneratorExpectedResults/JavaInterop1/WriteInterface.txt

@@ -5,7 +5,7 @@
 namespace Xamarin.Test {
 
 	// Metadata.xml XPath interface reference: path="/api/package[@name='xamarin.test']/interface[@name='ExtendedInterface']"
-	[global::Java.Interop.JniTypeSignature ("xamarin/test/ExtendedInterface", GenerateJavaPeer=false)]
+	[global::Java.Interop.JniTypeSignature ("xamarin/test/ExtendedInterface", GenerateJavaPeer=false, InvokerType=typeof (Xamarin.Test.IExtendedInterfaceInvoker))]
 	public partial interface IExtendedInterface : IJavaPeerable {
 		// Metadata.xml XPath method reference: path="/api/package[@name='xamarin.test']/interface[@name='ExtendedInterface']/method[@name='extendedMethod' and count(parameter)=0]"
 		[global::Java.Interop.JniMethodSignature ("extendedMethod", "()V")]

tests/generator-Tests/expected.ji/AccessModifiers/Xamarin.Test.IExtendedInterface.cs

@@ -18,7 +18,7 @@ namespace Xamarin.Test {
 	[global::Java.Interop.JniTypeSignature ("xamarin/test/PublicClass", GenerateJavaPeer=false)]
 	public partial class PublicClass : global::Java.Lang.Object {
 		// Metadata.xml XPath interface reference: path="/api/package[@name='xamarin.test']/interface[@name='PublicClass.ProtectedInterface']"
-		[global::Java.Interop.JniTypeSignature ("xamarin/test/PublicClass$ProtectedInterface", GenerateJavaPeer=false)]
+		[global::Java.Interop.JniTypeSignature ("xamarin/test/PublicClass$ProtectedInterface", GenerateJavaPeer=false, InvokerType=typeof (Xamarin.Test.PublicClass.IProtectedInterfaceInvoker))]
 		protected internal partial interface IProtectedInterface : IJavaPeerable {
 			// Metadata.xml XPath method reference: path="/api/package[@name='xamarin.test']/interface[@name='PublicClass.ProtectedInterface']/method[@name='foo' and count(parameter)=0]"
 			[global::Java.Interop.JniMethodSignature ("foo", "()V")]

tests/generator-Tests/expected.ji/AccessModifiers/Xamarin.Test.PublicClass.cs

@@ -15,7 +15,7 @@
 namespace Xamarin.Test {
 
 	// Metadata.xml XPath class reference: path="/api/package[@name='xamarin.test']/class[@name='AbsSpinner']"
-	[global::Java.Interop.JniTypeSignature ("xamarin/test/AbsSpinner", GenerateJavaPeer=false)]
+	[global::Java.Interop.JniTypeSignature ("xamarin/test/AbsSpinner", GenerateJavaPeer=false, InvokerType=typeof (AbsSpinnerInvoker))]
 	public abstract partial class AbsSpinner : Xamarin.Test.AdapterView<Xamarin.Test.ISpinnerAdapter> {
 		static readonly JniPeerMembers _members = new JniPeerMembers ("xamarin/test/AbsSpinner", typeof (AbsSpinner));