[GC Bridge] Split ManagedValueManager and SimpleValueManager (#10222)

Context: #10198

This PR contains bits from #10198 which don't depend on new APIs in dotnet/runtime.

* Turn `ManagedValueManager` into singleton, for safety/correctness, as we
don't want to be calling `JavaMarsha.Initialize()` more than once.

* Create `SimpleValueManager` for NativeAOT, which is the "simple" implementation
that just leaks...

Eventually, `ManagedValueManager` will use the new `JavaMarshal` APIs
and `SimpleValueManager` will be used temporarily for NativeAOT.

`SimpleValueManager` can be removed in the future when `JavaMarshal`
is implemented for NativeAOT.

Author: simonrozsival

src/Microsoft.Android.Runtime.NativeAOT/Android.Runtime.NativeAOT/JavaInteropRuntime.cs

@@ -43,7 +43,7 @@ static void init (IntPtr jnienv, IntPtr klass, IntPtr classLoader)
 				EnvironmentPointer          = jnienv,
 				ClassLoader                 = new JniObjectReference (classLoader),
 				TypeManager                 = typeManager,
-				ValueManager                = new ManagedValueManager (),
+				ValueManager                = new SimpleValueManager (),
 				UseMarshalMemberBuilder     = false,
 				JniGlobalReferenceLogWriter = settings.GrefLog,
 				JniLocalReferenceLogWriter  = settings.LrefLog,

src/Microsoft.Android.Runtime.NativeAOT/Java.Interop/JreRuntime.cs

@@ -61,7 +61,7 @@ static NativeAotRuntimeOptions CreateJreVM (NativeAotRuntimeOptions builder)
 			builder.TypeManager     ??= new ManagedTypeManager ();
 #endif  // NET
 
-			builder.ValueManager            ??= new ManagedValueManager ();
+			builder.ValueManager            ??= new SimpleValueManager ();
 			builder.ObjectReferenceManager  ??= new ManagedObjectReferenceManager (builder.JniGlobalReferenceLogWriter, builder.JniLocalReferenceLogWriter);
 
 			if (builder.InvocationPointer != IntPtr.Zero || builder.EnvironmentPointer != IntPtr.Zero)

src/Mono.Android/Android.Runtime/AndroidRuntime.cs

@@ -58,15 +58,15 @@ public override string GetCurrentManagedThreadStackTrace (int skipFrames, bool f
 		{
 			if (!reference.IsValid)
 				return null;
-			var peeked      = JNIEnvInit.ValueManager?.PeekPeer (reference);
+			var peeked      = JniEnvironment.Runtime.ValueManager.PeekPeer (reference);
 			var peekedExc   = peeked as Exception;
 			if (peekedExc == null) {
 				var throwable = Java.Lang.Object.GetObject<Java.Lang.Throwable> (reference.Handle, JniHandleOwnership.DoNotTransfer);
 				JniObjectReference.Dispose (ref reference, options);
 				return throwable;
 			}
 			JniObjectReference.Dispose (ref reference, options);
-			var unwrapped = JNIEnvInit.ValueManager?.PeekValue (peeked!.PeerReference) as Exception;
+			var unwrapped = JniEnvironment.Runtime.ValueManager.PeekValue (peeked!.PeerReference) as Exception;
 			if (unwrapped != null) {
 				return unwrapped;
 			}

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

@@ -118,7 +118,7 @@ internal static void PropagateUncaughtException (IntPtr env, IntPtr javaThreadPt
 
 		public static void WaitForBridgeProcessing ()
 		{
-			JNIEnvInit.ValueManager?.WaitForGCBridgeProcessing ();
+			JniEnvironment.Runtime.ValueManager.WaitForGCBridgeProcessing ();
 		}
 
 		public static IntPtr AllocObject (string jniClassName)

src/Mono.Android/Android.Runtime/JNIEnvInit.cs

@@ -40,7 +40,6 @@ internal struct JnienvInitializeArgs {
 		}
 #pragma warning restore 0649
 
-		internal static JniRuntime.JniValueManager? ValueManager;
 		internal static bool IsRunningOnDesktop;
 		internal static bool jniRemappingInUse;
 		internal static bool MarshalMethodsEnabled;
@@ -88,7 +87,6 @@ static Type TypeGetType (string typeName) =>
 		internal static void InitializeJniRuntime (JniRuntime runtime)
 		{
 			androidRuntime = runtime;
-			ValueManager = runtime.ValueManager;
 			SetSynchronizationContext ();
 		}
 
@@ -115,11 +113,15 @@ internal static unsafe void Initialize (JnienvInitializeArgs* args)
 			JniRuntime.JniValueManager valueManager;
 			if (RuntimeFeature.ManagedTypeMap) {
 				typeManager     = new ManagedTypeManager ();
-				valueManager    = new ManagedValueManager ();
 			} else {
 				typeManager     = new AndroidTypeManager (args->jniAddNativeMethodRegistrationAttributePresent != 0);
-				valueManager    = RuntimeType == DotNetRuntimeType.MonoVM ? new AndroidValueManager () : new ManagedValueManager ();
 			}
+			valueManager = RuntimeType switch
+			{
+				DotNetRuntimeType.MonoVM => new AndroidValueManager(),
+				DotNetRuntimeType.CoreCLR => ManagedValueManager.GetOrCreateInstance(),
+				_ => throw new NotSupportedException ($"No value manager for runtime type: {RuntimeType}"),
+			};
 			androidRuntime = new AndroidRuntime (
 					args->env,
 					args->javaVm,
@@ -128,7 +130,6 @@ internal static unsafe void Initialize (JnienvInitializeArgs* args)
 					valueManager,
 					args->jniAddNativeMethodRegistrationAttributePresent != 0
 			);
-			ValueManager = androidRuntime.ValueManager;
 
 			IsRunningOnDesktop = args->isRunningOnDesktop == 1;
 

src/Mono.Android/Android.Runtime/JNINativeWrapper.g.cs

@@ -268,7 +268,7 @@ foreach (var info in delegateTypes) {
 #>
 		internal static <#= info.Return #> Wrap<#= info.Type #> (this <#= info.Type #> callback, <#= info.Signature #>)
 		{
-			JNIEnvInit.ValueManager?.WaitForGCBridgeProcessing ();
+			Java.Interop.JniEnvironment.Runtime.ValueManager.WaitForGCBridgeProcessing ();
 			try {
 				<#= info.Return != "void" ? "return " : "" #>callback (<#= info.Invoke #>);
 			} catch (Exception e) when (_unhandled_exception (e)) {

src/Mono.Android/Android.Runtime/JNINativeWrapper.g.tt

@@ -11,7 +11,7 @@ public static class Runtime {
 		[Obsolete ("Please use Java.Interop.JniEnvironment.Runtime.ValueManager.GetSurfacedPeers()")]
 		public static List<WeakReference> GetSurfacedObjects ()
 		{
-			var peers = JNIEnvInit.ValueManager!.GetSurfacedPeers ();
+			var peers = JniEnvironment.Runtime.ValueManager.GetSurfacedPeers ();
 			var r = new List<WeakReference> (peers.Count);
 			foreach (var p in peers) {
 				if (p.SurfacedPeer.TryGetTarget (out var target))

src/Mono.Android/Java.Interop/Runtime.cs

@@ -111,7 +111,7 @@ protected void SetHandle (IntPtr value, JniHandleOwnership transfer)
 		{
 			var reference = new JniObjectReference (value);
 			var options   = FromJniHandleOwnership (transfer);
-			JNIEnvInit.ValueManager?.ConstructPeer (
+			JniEnvironment.Runtime.ValueManager.ConstructPeer (
 					this,
 					ref reference,
 					value == IntPtr.Zero ? JniObjectReferenceOptions.None : options);
@@ -128,7 +128,7 @@ static JniObjectReferenceOptions FromJniHandleOwnership (JniHandleOwnership tran
 
 		internal static IJavaPeerable? PeekObject (IntPtr handle, Type? requiredType = null)
 		{
-			var peeked  = JNIEnvInit.ValueManager?.PeekPeer (new JniObjectReference (handle));
+			var peeked  = JniEnvironment.Runtime.ValueManager.PeekPeer (new JniObjectReference (handle));
 			if (peeked == null)
 				return null;
 			if (requiredType != null && !requiredType.IsAssignableFrom (peeked.GetType ()))
@@ -180,7 +180,7 @@ internal static T? _GetObject<
 			if (handle == IntPtr.Zero)
 				return null;
 
-			var r = JNIEnvInit.ValueManager!.GetPeer (new JniObjectReference (handle), type);
+			var r = JniEnvironment.Runtime.ValueManager.GetPeer (new JniObjectReference (handle), type);
 			JNIEnv.DeleteRef (handle, transfer);
 			return r;
 		}

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

@@ -22,7 +22,10 @@ class ManagedValueManager : JniRuntime.JniValueManager
 
 	Dictionary<int, List<IJavaPeerable>>?   RegisteredInstances = new Dictionary<int, List<IJavaPeerable>>();
 
-	internal ManagedValueManager ()
+	static Lazy<ManagedValueManager> s_instance = new (() => new ManagedValueManager ());
+	public static ManagedValueManager GetOrCreateInstance () => s_instance.Value;
+
+	ManagedValueManager ()
 	{
 	}