Expose api's for Context on ObjectReference. (#1466)

* Expose api's for Context on ObjectReference.

* Add GC.KeepAlive.

* Add old signature back.

* Keep Resurrect.

* Use Unsafe.AsRef

* Update projections.

* Fix.

* Update baseline.

* Use virtual method to safe cost of a field in every instance.

* Fix passing iid.

src/WinRT.Runtime/ComWrappersSupport.cs

@@ -75,14 +75,15 @@ public static void MarshalDelegateInvoke<T>(IntPtr thisPtr, Action<T> invoke)
 
         // If we are free threaded, we do not need to keep track of context.
         // This can either be if the object implements IAgileObject or the free threaded marshaler.
-        internal unsafe static bool IsFreeThreaded(IObjectReference objRef)
+        internal unsafe static bool IsFreeThreaded(IntPtr iUnknown)
         {
-            if (objRef.TryAs(InterfaceIIDs.IAgileObject_IID, out var agilePtr) >= 0)
+            if (Marshal.QueryInterface(iUnknown, ref Unsafe.AsRef(InterfaceIIDs.IAgileObject_IID), out var agilePtr) >= 0)
             {
                 Marshal.Release(agilePtr);
                 return true;
             }
-            else if (objRef.TryAs(InterfaceIIDs.IMarshal_IID, out var marshalPtr) >= 0)
+
+            if (Marshal.QueryInterface(iUnknown, ref Unsafe.AsRef(InterfaceIIDs.IMarshal_IID), out var marshalPtr) >= 0)
             {
                 try
                 {
@@ -103,6 +104,14 @@ internal unsafe static bool IsFreeThreaded(IObjectReference objRef)
             return false;
         }
 
+        internal unsafe static bool IsFreeThreaded(IObjectReference objRef)
+        {
+            var isFreeThreaded = IsFreeThreaded(objRef.ThisPtr);
+            // ThisPtr is owned by objRef, so need to make sure objRef stays alive.
+            GC.KeepAlive(objRef);
+            return isFreeThreaded;
+        }
+
         public static IObjectReference GetObjectReferenceForInterface(IntPtr externalComObject)
         {
             return GetObjectReferenceForInterface<IUnknownVftbl>(externalComObject);
@@ -115,21 +124,7 @@ public static ObjectReference<T> GetObjectReferenceForInterface<T>(IntPtr extern
                 return null;
             }
 
-            ObjectReference<T> objRef = ObjectReference<T>.FromAbi(externalComObject);
-            if (IsFreeThreaded(objRef))
-            {
-                return objRef;
-            }
-            else
-            {
-                using (objRef)
-                {
-                    return new ObjectReferenceWithContext<T>(
-                        objRef.GetRef(),
-                        Context.GetContextCallback(),
-                        Context.GetContextToken());
-                }
-            }
+            return ObjectReference<T>.FromAbi(externalComObject);
         }
 
         public static ObjectReference<T> GetObjectReferenceForInterface<T>(IntPtr externalComObject, Guid iid)
@@ -144,31 +139,14 @@ internal static ObjectReference<T> GetObjectReferenceForInterface<T>(IntPtr exte
                 return null;
             }
 
-            ObjectReference<T> objRef;
             if (requireQI)
             {
                 Marshal.ThrowExceptionForHR(Marshal.QueryInterface(externalComObject, ref iid, out IntPtr ptr));
-                objRef = ObjectReference<T>.Attach(ref ptr);
+                return ObjectReference<T>.Attach(ref ptr, iid);
             }
             else
             {
-                objRef = ObjectReference<T>.FromAbi(externalComObject);
-            }
-
-            if (IsFreeThreaded(objRef))
-            {
-                return objRef;
-            }
-            else
-            {
-                using (objRef)
-                {
-                    return new ObjectReferenceWithContext<T>(
-                        objRef.GetRef(),
-                        Context.GetContextCallback(),
-                        Context.GetContextToken(),
-                        iid);
-                }
+                return ObjectReference<T>.FromAbi(externalComObject, iid);
             }
         }
 
@@ -487,7 +465,12 @@ private static Func<IInspectable, object> CreateCustomTypeMappingFactory(Type cu
             }
 
             var fromAbiMethodFunc = (Func<IntPtr, object>) fromAbiMethod.CreateDelegate(typeof(Func<IntPtr, object>));
-            return (IInspectable obj) => fromAbiMethodFunc(obj.ThisPtr);
+            return (IInspectable obj) =>
+            {
+                var fromAbiMethod = fromAbiMethodFunc(obj.ThisPtr);
+                GC.KeepAlive(obj);
+                return fromAbiMethod;
+            };
         }
 
         internal static Func<IInspectable, object> CreateTypedRcwFactory(

src/WinRT.Runtime/ComWrappersSupport.net5.cs

@@ -175,7 +175,7 @@ public static object TryRegisterObjectForInterface(object obj, IntPtr thisPtr)
         public static IObjectReference CreateCCWForObject(object obj)
         {
             IntPtr ccw = ComWrappers.GetOrCreateComInterfaceForObject(obj, CreateComInterfaceFlags.TrackerSupport);
-            return ObjectReference<IUnknownVftbl>.Attach(ref ccw);
+            return ObjectReference<IUnknownVftbl>.Attach(ref ccw, InterfaceIIDs.IUnknown_IID);
         }
 
         internal static IntPtr CreateCCWForObjectForABI(object obj, Guid iid)
@@ -350,8 +350,7 @@ public unsafe static void Init(
                 // otherwise the new instance will be used. Since the inner was composed
                 // it should answer immediately without going through the outer. Either way
                 // the reference count will go to the new instance.
-                Guid iid = IReferenceTrackerVftbl.IID;
-                int hr = Marshal.QueryInterface(objRef.ThisPtr, ref iid, out referenceTracker);
+                int hr = Marshal.QueryInterface(objRef.ThisPtr, ref Unsafe.AsRef(IReferenceTrackerVftbl.IID), out referenceTracker);
                 if (hr != 0)
                 {
                     referenceTracker = default;
@@ -450,9 +449,8 @@ public unsafe static void Init(
         public unsafe static void Init(IObjectReference objRef, bool addRefFromTrackerSource = true)
         {
             if (objRef.ReferenceTrackerPtr == IntPtr.Zero)
-            {
-                Guid iid = IReferenceTrackerVftbl.IID;
-                int hr = Marshal.QueryInterface(objRef.ThisPtr, ref iid, out var referenceTracker);
+            {
+                int hr = Marshal.QueryInterface(objRef.ThisPtr, ref Unsafe.AsRef(IReferenceTrackerVftbl.IID), out var referenceTracker);
                 if (hr == 0)
                 {
                     // WinUI scenario

src/WinRT.Runtime/ExceptionHelpers.cs

@@ -364,6 +364,7 @@ public static void ReportUnhandledError(Exception ex)
                 if (restrictedErrorInfoRef != null)
                 {
                     roReportUnhandledError(restrictedErrorInfoRef.ThisPtr);
+                    GC.KeepAlive(restrictedErrorInfoRef);
                 }
             }
         }

src/WinRT.Runtime/Marshalers.cs

@@ -1581,8 +1581,7 @@ public static T FromAbi(IntPtr ptr)
             IntPtr iunknownPtr = IntPtr.Zero;
             try
             {
-                Guid iid_iunknown = IUnknownVftbl.IID;
-                Marshal.QueryInterface(ptr, ref iid_iunknown, out iunknownPtr);
+                Marshal.QueryInterface(ptr, ref Unsafe.AsRef(IUnknownVftbl.IID), out iunknownPtr);
                 if (IUnknownVftbl.IsReferenceToManagedObject(iunknownPtr))
                 {
                     return (T)ComWrappersSupport.FindObject<object>(iunknownPtr);

src/WinRT.Runtime/MatchingRefApiCompatBaseline.txt

@@ -131,4 +131,9 @@ MembersMustExist : Member 'public System.String WinRT.WindowsRuntimeTypeAttribut
 TypesMustExist : Type 'WinRT.WinRTExposedTypeAttribute' does not exist in the reference but it does exist in the implementation.
 MembersMustExist : Member 'public T ABI.System.Nullable<T>.GetValue(WinRT.IInspectable)' does not exist in the reference but it does exist in the implementation.
 TypesMustExist : Type 'WinRT.EventRegistrationTokenTable<T>' does not exist in the reference but it does exist in the implementation.
-Total Issues: 132
+MembersMustExist : Member 'public System.Boolean WinRT.IObjectReference.IsFreeThreaded.get()' does not exist in the reference but it does exist in the implementation.
+MembersMustExist : Member 'public System.Boolean WinRT.IObjectReference.IsInCurrentContext.get()' does not exist in the reference but it does exist in the implementation.
+MembersMustExist : Member 'public WinRT.ObjectReference<T> WinRT.ObjectReference<T>.Attach(System.IntPtr, System.Guid)' does not exist in the reference but it does exist in the implementation.
+MembersMustExist : Member 'public WinRT.ObjectReference<T> WinRT.ObjectReference<T>.FromAbi(System.IntPtr, System.Guid)' does not exist in the reference but it does exist in the implementation.
+MembersMustExist : Member 'public WinRT.ObjectReference<T> WinRT.ObjectReference<T>.FromAbi(System.IntPtr, T, System.Guid)' does not exist in the reference but it does exist in the implementation.
+Total Issues: 137