Unwrap RCWs when using the global marshalling instance via the COM Marshal APIs.

Author: jkoritzinsky

src/coreclr/System.Private.CoreLib/src/System/Runtime/InteropServices/ComWrappers.CoreCLR.cs

@@ -58,11 +58,14 @@ internal static int CallICustomQueryInterface(ManagedObjectWrapperHolder holder,
 
         internal static IntPtr GetOrCreateComInterfaceForObjectWithGlobalMarshallingInstance(object obj)
         {
+            if (s_globalInstanceForMarshalling == null)
+            {
+                return IntPtr.Zero;
+            }
+
             try
             {
-                return s_globalInstanceForMarshalling is null
-                    ? IntPtr.Zero
-                    : s_globalInstanceForMarshalling.GetOrCreateComInterfaceForObject(obj, CreateComInterfaceFlags.TrackerSupport);
+                return ComInterfaceForObject(obj);
             }
             catch (ArgumentException)
             {
@@ -74,9 +77,14 @@ internal static IntPtr GetOrCreateComInterfaceForObjectWithGlobalMarshallingInst
 
         internal static object? GetOrCreateObjectForComInstanceWithGlobalMarshallingInstance(IntPtr comObject, CreateObjectFlags flags)
         {
+            if (s_globalInstanceForMarshalling == null)
+            {
+                return IntPtr.Zero;
+            }
+
             try
             {
-                return s_globalInstanceForMarshalling?.GetOrCreateObjectForComInstance(comObject, flags);
+                return ComObjectForInterface(comObject, flags);
             }
             catch (ArgumentNullException)
             {

src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/ComWrappers.cs

@@ -1404,7 +1404,12 @@ internal static IntPtr ComInterfaceForObject(object instance)
                 throw new NotSupportedException(SR.InvalidOperation_ComInteropRequireComWrapperInstance);
             }
 
-            return s_globalInstanceForMarshalling.GetOrCreateComInterfaceForObject(instance, CreateComInterfaceFlags.None);
+            if (TryGetComInstance(instance, out IntPtr comObject))
+            {
+                return comObject;
+            }
+
+            return s_globalInstanceForMarshalling.GetOrCreateComInterfaceForObject(instance, CreateComInterfaceFlags.TrackerSupport);
         }
 
         internal static unsafe IntPtr ComInterfaceForObject(object instance, Guid targetIID)
@@ -1423,15 +1428,15 @@ internal static unsafe IntPtr ComInterfaceForObject(object instance, Guid target
             return comObjectInterface;
         }
 
-        internal static object ComObjectForInterface(IntPtr externalComObject)
+        internal static object ComObjectForInterface(IntPtr externalComObject, CreateObjectFlags flags = CreateObjectFlags.TrackerObject | CreateObjectFlags.Unwrap)
         {
             if (s_globalInstanceForMarshalling == null)
             {
                 throw new NotSupportedException(SR.InvalidOperation_ComInteropRequireComWrapperInstance);
             }
 
             // TrackerObject support and unwrapping matches the built-in semantics that the global marshalling scenario mimics.
-            return s_globalInstanceForMarshalling.GetOrCreateObjectForComInstance(externalComObject, CreateObjectFlags.TrackerObject | CreateObjectFlags.Unwrap);
+            return s_globalInstanceForMarshalling.GetOrCreateObjectForComInstance(externalComObject, flags);
         }
 
         internal static IntPtr GetOrCreateTrackerTarget(IntPtr externalComObject)

src/tests/Interop/COM/ComWrappers/GlobalInstance/GlobalInstance.cs

@@ -49,6 +49,7 @@ extern public static int UpdateTestObjectAsInterface(
 
         private const string ManagedServerTypeName = "ConsumeNETServerTesting";
 
+        private const string IID_IUNKNOWN = "00000000-0000-0000-C000-000000000046";
         private const string IID_IDISPATCH = "00020400-0000-0000-C000-000000000046";
         private const string IID_IINSPECTABLE = "AF86E2E0-B12D-4c6a-9C5A-D7AA65101E90";
         class TestEx : Test
@@ -278,7 +279,7 @@ private static void ValidateMarshalAPIs(bool validateUseRegistered)
             var testObj = new Test();
             IntPtr comWrapper1 = Marshal.GetIUnknownForObject(testObj);
             Assert.NotEqual(IntPtr.Zero, comWrapper1);
-            Assert.Equal(testObj, registeredWrapper.LastComputeVtablesObject);
+            Assert.Same(testObj, registeredWrapper.LastComputeVtablesObject);
 
             IntPtr comWrapper2 = Marshal.GetIUnknownForObject(testObj);
             Assert.Equal(comWrapper1, comWrapper2);
@@ -295,7 +296,7 @@ private static void ValidateMarshalAPIs(bool validateUseRegistered)
                 var dispatchObj = new TestEx(IID_IDISPATCH);
                 IntPtr dispatchWrapper = Marshal.GetIDispatchForObject(dispatchObj);
                 Assert.NotEqual(IntPtr.Zero, dispatchWrapper);
-                Assert.Equal(dispatchObj, registeredWrapper.LastComputeVtablesObject);
+                Assert.Same(dispatchObj, registeredWrapper.LastComputeVtablesObject);
 
                 Console.WriteLine($" -- Validate Marshal.GetIDispatchForObject != Marshal.GetIUnknownForObject...");
                 IntPtr unknownWrapper = Marshal.GetIUnknownForObject(dispatchObj);
@@ -309,7 +310,7 @@ private static void ValidateMarshalAPIs(bool validateUseRegistered)
             object objWrapper1 = Marshal.GetObjectForIUnknown(trackerObjRaw);
             Assert.Equal(validateUseRegistered, objWrapper1 is FakeWrapper);
             object objWrapper2 = Marshal.GetObjectForIUnknown(trackerObjRaw);
-            Assert.Equal(objWrapper1, objWrapper2);
+            Assert.Same(objWrapper1, objWrapper2);
 
             Console.WriteLine($" -- Validate Marshal.GetUniqueObjectForIUnknown...");
 
@@ -319,6 +320,29 @@ private static void ValidateMarshalAPIs(bool validateUseRegistered)
             Assert.NotEqual(objWrapper1, objWrapper3);
 
             Marshal.Release(trackerObjRaw);
+
+            if (validateUseRegistered)
+            {
+                Console.WriteLine($" -- Validate Marshal.GetObjectForIUnknown and Marshal.GetIUnknownForObject unwrapping...");
+                // Validate that the object returned by Marshal.GetObjectForIUnknown is the same as the original object passed to
+                // Marshal.GetIUnknownForObject.
+                IntPtr comWrapper3 = Marshal.GetIUnknownForObject(testObj);
+                object unwrappedObj = Marshal.GetObjectForIUnknown(comWrapper3);
+                Assert.Same(testObj, unwrappedObj);
+
+                // Validate that the pointer returned by Marshal.GetIUnknownForObject is the same one that was passed into
+                // Marshal.GetObjectForIUnknown.
+                IntPtr trackerObj2 = MockReferenceTrackerRuntime.CreateTrackerObject();
+                Marshal.ThrowExceptionForHR(Marshal.QueryInterface(trackerObj2, Guid.Parse(IID_IUNKNOWN), out IntPtr trackerObj2Identity));
+                Marshal.Release(trackerObj2);
+
+                object trackerObjectWrapper = Marshal.GetObjectForIUnknown(trackerObj2);
+                IntPtr trackerObjUnwrapped = Marshal.GetIUnknownForObject(trackerObjectWrapper);
+                Assert.Equal(trackerObj2Identity, trackerObjUnwrapped);
+
+                Marshal.Release(trackerObj2Identity);
+                Marshal.Release(trackerObjUnwrapped);
+            }
         }
 
         private static void ValidatePInvokes(bool validateUseRegistered)
@@ -362,12 +386,12 @@ private static void ValidateInterfaceMarshaler<T>(UpdateTestObject<T> func, bool
 
             T retObj;
             int hr = func(testObj as T, value, out retObj);
-            Assert.Equal(testObj, GlobalComWrappers.Instance.LastComputeVtablesObject);
+            Assert.Same(testObj, GlobalComWrappers.Instance.LastComputeVtablesObject);
             if (shouldSucceed)
             {
                 Assert.True(retObj is Test);
                 Assert.Equal(value, testObj.GetValue());
-                Assert.Equal<object>(testObj, retObj);
+                Assert.Same(testObj, retObj);
             }
             else
             {