[Mono.Android] Java.Lang.Object.GetObject<T>() implementation

The current implementation:

    return Java.Interop.TypeManager.CreateInstance (handle, transfer, type);

Needs to become this, for NativeAOT support:

    JniObjectReference reference = JNIEnv.CreateJniObjectReference (handle);
    JniObjectReferenceOptions options = JNIEnv.ToJniObjectReferenceOptions (transfer);
    return (IJavaPeerable) JNIEnvInit.AndroidValueManager?.GetValue (ref reference, options, type);

This way we use the appropriate `AndroidValueManager` for the runtime
that is currently being used. If we just change the code in
`Java.Lang.Object` to do this for all runtimes, this can keep
everything a bit simpler.

The fallout of this change requires `type` to be decorated with:

    [DynamicallyAccessedMembers (Constructors)]

This trickled to create many other trimmer warnings, that are likely a
real issue. This is a good opportunity to fix them.

I also defined the `const` value in `Java.Lang.Object`:

    internal const DynamicallyAccessedMemberTypes Constructors = DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors;

Which allowed many types that extend `Java.Lang.Object` able to reuse
this `const` value and not define it again.

I also had to make a helper function to map `JniHandleOwnership` ->
`JniObjectReferenceOptions`, such as:

    internal static JniObjectReferenceOptions ToJniObjectReferenceOptions (JniHandleOwnership transfer)

And `CreateJniObjectReference()`:

    internal static JniObjectReference CreateJniObjectReference (IntPtr handle, JniHandleOwnership transfer)

Other changes:

* Bump to dotnet/java-interop@2c06b3c2a

Changes: dotnet/java-interop@f800ea5...2c06b3c

src/Mono.Android/Android.App/Activity.cs

@@ -6,8 +6,6 @@ namespace Android.App {
 
 	partial class Activity {
 
-		internal const DynamicallyAccessedMemberTypes Constructors = DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors;
-
 		public T? FindViewById<
 				[DynamicallyAccessedMembers (Constructors)]
 				T

src/Mono.Android/Android.App/Dialog.cs

@@ -10,7 +10,7 @@ protected Dialog (Android.Content.Context context, bool cancelable, EventHandler
 			: this (context, cancelable, new Android.Content.IDialogInterfaceOnCancelListenerImplementor () { Handler = cancelHandler }) {}
 
 		public T? FindViewById<
-				[DynamicallyAccessedMembers (DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors)]
+				[DynamicallyAccessedMembers (Constructors)]
 				T
 		> (int id)
 			where T : Android.Views.View

src/Mono.Android/Android.App/FragmentManager.cs

@@ -5,8 +5,6 @@
 #if ANDROID_11
 namespace Android.App {
 	public partial class FragmentManager {
-		const DynamicallyAccessedMemberTypes Constructors = DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors;
-
 		public T? FindFragmentById<
 				[DynamicallyAccessedMembers (Constructors)]
 				T

src/Mono.Android/Android.Graphics/Color.cs

@@ -395,7 +395,7 @@ public static void RGBToHSV (int red, int green, int blue, float[] hsv)
 
 	public class ColorValueMarshaler : JniValueMarshaler<Color>
 	{
-		const DynamicallyAccessedMemberTypes ConstructorsAndInterfaces = DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors | DynamicallyAccessedMemberTypes.Interfaces;
+		const DynamicallyAccessedMemberTypes Constructors = DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors;
 		const string ExpressionRequiresUnreferencedCode = "System.Linq.Expression usage may trim away required code.";
 
 		public override Type MarshalType {
@@ -405,7 +405,7 @@ public override Type MarshalType {
 		public override Color CreateGenericValue (
 				ref JniObjectReference reference,
 				JniObjectReferenceOptions options,
-				[DynamicallyAccessedMembers (ConstructorsAndInterfaces)]
+				[DynamicallyAccessedMembers (Constructors)]
 				Type targetType)
 		{
 			throw new NotImplementedException ();

src/Mono.Android/Android.OS/AsyncTask.cs

@@ -18,8 +18,6 @@ public abstract class AsyncTask<
 			TResult
 	> : AsyncTask {
 
-		const DynamicallyAccessedMemberTypes Constructors = DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors;
-
 		static IntPtr java_class_handle;
 		internal static IntPtr class_ref {
 			get {

src/Mono.Android/Android.Runtime/IJavaObjectValueMarshaler.cs

@@ -10,15 +10,15 @@ namespace Android.Runtime
 {
 	sealed class IJavaObjectValueMarshaler : JniValueMarshaler<IJavaObject> {
 
-		const DynamicallyAccessedMemberTypes ConstructorsAndInterfaces = DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors | DynamicallyAccessedMemberTypes.Interfaces;
+		const DynamicallyAccessedMemberTypes Constructors = DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors;
 		const string ExpressionRequiresUnreferencedCode = "System.Linq.Expression usage may trim away required code.";
 
 		internal    static  IJavaObjectValueMarshaler              Instance    = new IJavaObjectValueMarshaler ();
 
 		public override IJavaObject CreateGenericValue (
 				ref JniObjectReference reference,
 				JniObjectReferenceOptions options,
-				[DynamicallyAccessedMembers (ConstructorsAndInterfaces)]
+				[DynamicallyAccessedMembers (Constructors)]
 				Type? targetType)
 		{
 			throw new NotImplementedException ();

src/Mono.Android/Android.Runtime/JNIEnv.cs

@@ -322,6 +322,29 @@ public static IntPtr FindClass (System.Type type)
 			}
 		}
 
+		internal static JniObjectReferenceOptions ToJniObjectReferenceOptions (JniHandleOwnership transfer)
+		{
+			JniObjectReferenceOptions options = default;
+			if (transfer.HasFlag (JniHandleOwnership.TransferLocalRef) ||
+					transfer.HasFlag (JniHandleOwnership.TransferGlobalRef))
+				options |= JniObjectReferenceOptions.CopyAndDispose;
+			if (transfer.HasFlag (JniHandleOwnership.DoNotRegister))
+				options |= JniObjectReferenceOptions.CopyAndDoNotRegister;
+			if (transfer == JniHandleOwnership.DoNotTransfer) // 0; can't use with .HasFlag()
+				options |= JniObjectReferenceOptions.Copy;
+
+			return options;
+		}
+
+		internal static JniObjectReference CreateJniObjectReference (IntPtr handle, JniHandleOwnership transfer)
+		{
+			if (transfer.HasFlag (JniHandleOwnership.TransferLocalRef))
+				return new JniObjectReference (handle, JniObjectReferenceType.Local);
+			if (transfer.HasFlag (JniHandleOwnership.TransferGlobalRef))
+				return new JniObjectReference (handle, JniObjectReferenceType.Global);
+			return new JniObjectReference (handle); // there be possible dragons here!
+		}
+
 		const int nameBufferLength = 1024;
 		[ThreadStatic] static char[]? nameBuffer;
 
@@ -704,7 +727,13 @@ public static void CopyArray (IntPtr src, string[] dest)
 					AssertIsJavaObject (type);
 
 					IntPtr elem = GetObjectArrayElement (source, index);
-					return Java.Lang.Object.GetObject (elem, JniHandleOwnership.TransferLocalRef, type);
+					return GetObject (elem, type);
+
+					// FIXME: Since a Dictionary<Type, Func> is used here, the trimmer will not be able to properly analyze `Type t`
+					// error IL2111: Method 'lambda expression' with parameters or return value with `DynamicallyAccessedMembersAttribute` is accessed via reflection. Trimmer can't guarantee availability of the requirements of the method.
+					[UnconditionalSuppressMessage ("Trimming", "IL2067", Justification = "FIXME: https://github.com/xamarin/xamarin-android/issues/8724")]
+					static object? GetObject (IntPtr e, Type t) =>
+						Java.Lang.Object.GetObject (e, JniHandleOwnership.TransferLocalRef, t);
 				} },
 				{ typeof (Array), (type, source, index) => {
 					IntPtr  elem      = GetObjectArrayElement (source, index);

src/Mono.Android/Android.Runtime/JavaArray.cs

@@ -1,12 +1,15 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
-
+using System.Diagnostics.CodeAnalysis;
 
 namespace Android.Runtime {
 
 	[Register ("mono/android/runtime/JavaArray", DoNotGenerateAcw=true)]
-	public sealed class JavaArray<T> : Java.Lang.Object, IList<T> {
+	public sealed class JavaArray<
+			[DynamicallyAccessedMembers (Constructors)]
+			T
+	> : Java.Lang.Object, IList<T> {
 
 		public JavaArray (IntPtr handle, JniHandleOwnership transfer)
 			: base (handle, transfer)

src/Mono.Android/Android.Runtime/JavaCollection.cs

@@ -14,8 +14,6 @@ namespace Android.Runtime {
 	// java.util.Collection allows null values
 	public class JavaCollection : Java.Lang.Object, System.Collections.ICollection {
 
-		internal const DynamicallyAccessedMemberTypes Constructors = DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors;
-
 		internal static IntPtr collection_class = JNIEnv.FindClass ("java/util/Collection");
 
 		internal static IntPtr id_add;

src/Mono.Android/Android.Runtime/JavaDictionary.cs

@@ -12,8 +12,6 @@ namespace Android.Runtime {
 	// java.util.HashMap allows null keys and values
 	public class JavaDictionary : Java.Lang.Object, System.Collections.IDictionary {
 
-		internal const DynamicallyAccessedMemberTypes Constructors = DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors;
-
 		class DictionaryEnumerator : IDictionaryEnumerator {
 
 			IEnumerator simple_enumerator;

src/Mono.Android/Android.Runtime/JavaList.cs

@@ -10,7 +10,6 @@ namespace Android.Runtime {
 	// java.util.ArrayList allows null values
 	public partial class JavaList : Java.Lang.Object, System.Collections.IList {
 
-		internal const DynamicallyAccessedMemberTypes Constructors = DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors;
 		internal static readonly JniPeerMembers list_members = new XAPeerMembers ("java/util/List", typeof (JavaList), isInterface: true);
 
 		//

src/Mono.Android/Android.Runtime/JavaSet.cs

@@ -269,7 +269,7 @@ public static IntPtr ToLocalJniHandle (ICollection? items)
 	[Register ("java/util/HashSet", DoNotGenerateAcw=true)]
 	// java.util.HashSet allows null
 	public class JavaSet<
-			[DynamicallyAccessedMembers (DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors)]
+			[DynamicallyAccessedMembers (Constructors)]
 			T
 	> : JavaSet, ICollection<T> {
 

src/Mono.Android/Android.Util/SparseArray.cs

@@ -9,7 +9,7 @@ namespace Android.Util
 {
 	[Register ("android/util/SparseArray", DoNotGenerateAcw=true)]
 	public partial class SparseArray<
-			[DynamicallyAccessedMembers (DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors)]
+			[DynamicallyAccessedMembers (Constructors)]
 			E
 	> : SparseArray
 	{

src/Mono.Android/Android.Views/View.cs

@@ -13,9 +13,6 @@ public enum SystemUiFlags {
 #endif
 
 	public partial class View {
-
-		internal const DynamicallyAccessedMemberTypes Constructors = DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors;
-
 #if ANDROID_16
 		[Obsolete ("This method uses wrong enum type. Please use PerformAccessibilityAction(Action) instead.")]
 		public bool PerformAccessibilityAction (GlobalAction action, Bundle arguments)

src/Mono.Android/Android.Views/Window.cs

@@ -7,7 +7,7 @@ namespace Android.Views {
 	partial class Window {
 
 		public T? FindViewById<
-				[DynamicallyAccessedMembers (DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors)]
+				[DynamicallyAccessedMembers (Constructors)]
 				T
 		> (int id)
 			where T : Android.Views.View

src/Mono.Android/Android.Widget/AdapterView.cs

@@ -51,7 +51,7 @@ public event EventHandler ItemSelectionCleared {
 
 	[Register ("android/widget/AdapterView", DoNotGenerateAcw=true)]
 	public abstract class AdapterView<
-			[DynamicallyAccessedMembers (DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors)]
+			[DynamicallyAccessedMembers (Constructors)]
 			T
 	> : AdapterView  where T : IAdapter {
 

src/Mono.Android/Android.Widget/ArrayAdapter.cs

@@ -9,7 +9,7 @@ namespace Android.Widget {
 
 	[Register ("android/widget/ArrayAdapter", DoNotGenerateAcw=true)]
 	public partial class ArrayAdapter<
-			[DynamicallyAccessedMembers (DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors)]
+			[DynamicallyAccessedMembers (Constructors)]
 			T
 	> : ArrayAdapter {
 

src/Mono.Android/Java.Lang/Object.cs

@@ -19,6 +19,8 @@ public partial class Object : IDisposable, IJavaObject, IJavaObjectEx
 		, IJavaPeerable
 #endif  // JAVA_INTEROP
 	{
+		internal const DynamicallyAccessedMemberTypes Constructors = DynamicallyAccessedMemberTypes.PublicConstructors | DynamicallyAccessedMemberTypes.NonPublicConstructors;
+
 		[NonSerialized] IntPtr key_handle;
 #pragma warning disable CS0649, CS0169, CS0414 // Suppress fields are never used warnings, these fields are used directly by monodroid-glue.cc
 		[NonSerialized] int refs_added;
@@ -263,28 +265,41 @@ protected void SetHandle (IntPtr value, JniHandleOwnership transfer)
 			return (T?)PeekObject (handle, typeof (T));
 		}
 
-		public static T? GetObject<T> (IntPtr jnienv, IntPtr handle, JniHandleOwnership transfer)
+		public static T? GetObject<
+				[DynamicallyAccessedMembers (Constructors)]
+				T
+		> (IntPtr jnienv, IntPtr handle, JniHandleOwnership transfer)
 			where T : class, IJavaObject
 		{
 			JNIEnv.CheckHandle (jnienv);
 			return GetObject<T> (handle, transfer);
 		}
 
-		public static T? GetObject<T> (IntPtr handle, JniHandleOwnership transfer)
+		public static T? GetObject<
+				[DynamicallyAccessedMembers (Constructors)]
+				T
+		> (IntPtr handle, JniHandleOwnership transfer)
 			where T : class, IJavaObject
 		{
 			return _GetObject<T>(handle, transfer);
 		}
 
-		internal static T? _GetObject<T> (IntPtr handle, JniHandleOwnership transfer)
+		internal static T? _GetObject<
+				[DynamicallyAccessedMembers (Constructors)]
+				T
+		> (IntPtr handle, JniHandleOwnership transfer)
 		{
 			if (handle == IntPtr.Zero)
 				return default (T);
 
 			return (T?) GetObject (handle, transfer, typeof (T));
 		}
 
-		internal static IJavaPeerable? GetObject (IntPtr handle, JniHandleOwnership transfer, Type? type = null)
+		internal static IJavaPeerable? GetObject (
+				IntPtr handle,
+				JniHandleOwnership transfer,
+				[DynamicallyAccessedMembers (Constructors)]
+				Type? type = null)
 		{
 			if (handle == IntPtr.Zero)
 				return null;
@@ -295,7 +310,9 @@ protected void SetHandle (IntPtr value, JniHandleOwnership transfer)
 				return r;
 			}
 
-			return Java.Interop.TypeManager.CreateInstance (handle, transfer, type);
+			JniObjectReference reference = JNIEnv.CreateJniObjectReference (handle);
+			JniObjectReferenceOptions options = JNIEnv.ToJniObjectReferenceOptions (transfer);
+			return (IJavaPeerable) JNIEnvInit.AndroidValueManager?.GetValue (ref reference, options, type);
 		}
 
 		[EditorBrowsable (EditorBrowsableState.Never)]

tests/api-compatibility/api-compat-exclude-attributes.txt

@@ -16,3 +16,4 @@ T:System.Runtime.CompilerServices.IteratorStateMachineAttribute
 T:System.Runtime.CompilerServices.NullableAttribute
 T:System.Runtime.CompilerServices.NullableContextAttribute
 T:System.Diagnostics.CodeAnalysis.DynamicDependencyAttribute
+T:System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembersAttribute