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