Add new api's to IObjectReference to safely use the underlying pointer.

src/WinRT.Runtime/ApiCompatBaseline.txt

@@ -13,6 +13,7 @@ TypesMustExist : Type 'ABI.System.ComponentModel.INotifyDataErrorInfo' does not
 CannotRemoveAttribute : Attribute 'System.Diagnostics.CodeAnalysis.DynamicallyAccessedMembersAttribute' exists on 'System.Type WinRT.Marshaler<T>.AbiType' in the contract but not the implementation.
 CannotMakeMemberNonVirtual : Member 'public System.Int32 WinRT.IObjectReference.TryAs<T>(System.Guid, WinRT.ObjectReference<T>)' is non-virtual in the implementation but is virtual in the contract.
 MembersMustExist : Member 'protected System.Boolean System.Boolean WinRT.IObjectReference.disposed' does not exist in the implementation but it does exist in the contract.
-MembersMustExist : Member 'protected void WinRT.IObjectReference.Dispose(System.Boolean)' does not exist in the implementation but it does exist in the contract.
 CannotChangeAttribute : Attribute 'System.Diagnostics.CodeAnalysis.UnconditionalSuppressMessageAttribute' on 'ABI.System.Type.FromAbi(ABI.System.Type)' changed from '[UnconditionalSuppressMessageAttribute("ReflectionAnalysis", "IL2026:RequiresUnreferencedCode", Justification="Any types which are trimmed are not used by managed user code and there is fallback logic to handle that.")]' in the contract to '[UnconditionalSuppressMessageAttribute("ReflectionAnalysis", "IL2057", Justification="Any types which are trimmed are not used by managed user code and there is fallback logic to handle that.")]' in the implementation.
-Total Issues: 16
+MembersMustExist : Member 'protected void WinRT.IObjectReference.ThrowIfDisposed()' does not exist in the implementation but it does exist in the contract.
+MembersMustExist : Member 'protected WinRT.Interop.IUnknownVftbl WinRT.IObjectReference.VftblIUnknown.get()' does not exist in the implementation but it does exist in the contract.
+Total Issues: 17

src/WinRT.Runtime/CastExtensions.cs

@@ -34,7 +34,7 @@ public static TInterface As<TInterface>(this object value)
                 {
                     using (objRef)
                     {
-                        return ComWrappersSupport.CreateRcwForComObject<TInterface>(objRef.ThisPtr);
+                        return ComWrappersSupport.CreateRcwForComObject<TInterface>(objRef.DangerousGetPtr());
                     }
                 }
             }

src/WinRT.Runtime/ComWrappersSupport.cs

@@ -106,10 +106,20 @@ internal unsafe static bool IsFreeThreaded(IntPtr iUnknown)
 
         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;
+            bool success = false;
+            try
+            {
+                objRef.DangerousAddRef(ref success);
+                var thisPtr = objRef.DangerousGetPtr();
+                return IsFreeThreaded(thisPtr);
+            }
+            finally
+            {
+                if (success)
+                {
+                    objRef.DangerousRelease();
+                }
+            }
         }
 
         public static IObjectReference GetObjectReferenceForInterface(IntPtr externalComObject)

src/WinRT.Runtime/ComWrappersSupport.net5.cs

@@ -333,7 +333,7 @@ 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.
-                int hr = Marshal.QueryInterface(objRef.ThisPtr, ref Unsafe.AsRef(IReferenceTrackerVftbl.IID), out referenceTracker);
+                int hr = Marshal.QueryInterface(objRef.DangerousGetPtr(), ref Unsafe.AsRef(IReferenceTrackerVftbl.IID), out referenceTracker);
                 if (hr != 0)
                 {
                     referenceTracker = default;

src/WinRT.Runtime/ComWrappersSupport.netstandard2.0.cs

@@ -71,15 +71,15 @@ private static T CreateRcwForComObject<T>(IntPtr ptr, bool tryUseCache)
 
                 keepAliveSentinel = runtimeWrapper; // We don't take a strong reference on runtimeWrapper at any point, so we need to make sure it lives until it can get assigned to rcw.
                 var runtimeWrapperReference = new System.WeakReference<object>(runtimeWrapper);
-                var cleanupSentinel = new RuntimeWrapperCleanup(identity.ThisPtr, runtimeWrapperReference);
+                var cleanupSentinel = new RuntimeWrapperCleanup(identity.DangerousGetPtr(), runtimeWrapperReference);
                 return runtimeWrapperReference;
             };
 
             object rcw;
             if (tryUseCache)
             {
                 RuntimeWrapperCache.AddOrUpdate(
-                    identity.ThisPtr,
+                    identity.DangerousGetPtr(),
                     rcwFactory,
                     (ptr, oldValue) =>
                     {

src/WinRT.Runtime/ExceptionHelpers.cs

@@ -319,7 +319,7 @@ public static unsafe void SetErrorInfo(Exception ex)
             {
                 // If the exception has information for an IRestrictedErrorInfo, use that
                 // as our error so as to propagate the error through WinRT end-to-end.
-                if (ex.TryGetRestrictedLanguageErrorObject(out var restrictedErrorObject))
+                if (ex.TryGetRestrictedLanguageErrorObject(out IObjectReference restrictedErrorObject))
                 {
                     using (restrictedErrorObject)
                     {

src/WinRT.Runtime/IInspectable.cs

@@ -135,9 +135,12 @@ public IInspectable(ObjectReference<Vftbl> obj)
         public unsafe string GetRuntimeClassName(bool noThrow = false)
         {
             IntPtr __retval = default;
+            bool success = false;
             try
             {
-                var hr = _obj.Vftbl.GetRuntimeClassName(ThisPtr, &__retval);
+                _obj.DangerousAddRef(ref success);
+                var thisPtr = _obj.DangerousGetPtr();
+                var hr = _obj.Vftbl.GetRuntimeClassName(thisPtr, &__retval);
                 if (hr != 0)
                 {
                     if (noThrow)
@@ -151,6 +154,10 @@ public unsafe string GetRuntimeClassName(bool noThrow = false)
             finally
             {
                 Platform.WindowsDeleteString(__retval);
+                if (success)
+                {
+                    _obj.DangerousRelease();
+                }
             }
         }
     }

src/WinRT.Runtime/Interop/ExceptionErrorInfo.cs

@@ -263,6 +263,8 @@ private static int Do_Abi_GetHelpFileContent_4(IntPtr thisPtr, IntPtr* helpFileC
         public static implicit operator IErrorInfo(IObjectReference obj) => (obj != null) ? new IErrorInfo(obj) : null;
         public static implicit operator IErrorInfo(ObjectReference<Vftbl> obj) => (obj != null) ? new IErrorInfo(obj) : null;
         protected readonly ObjectReference<Vftbl> _obj;
+        public IObjectReference ObjRef { get => _obj; }
+        [Obsolete]
         public IntPtr ThisPtr => _obj.ThisPtr;
         public ObjectReference<I> AsInterface<I>() => _obj.As<I>();
         public A As<A>() => _obj.AsType<A>();
@@ -275,63 +277,104 @@ public IErrorInfo(ObjectReference<Vftbl> obj)
         public Guid GetGuid()
         {
             Guid __return_value__;
-            Marshal.ThrowExceptionForHR(_obj.Vftbl.GetGuid_0(ThisPtr, &__return_value__));
-            return __return_value__;
+            bool success = false;
+            try
+            {
+                _obj.DangerousAddRef(ref success);
+                var thisPtr = _obj.DangerousGetPtr();
+                Marshal.ThrowExceptionForHR(_obj.Vftbl.GetGuid_0(thisPtr, &__return_value__));
+                return __return_value__;
+            }
+            finally
+            {
+                if (success)
+                {
+                    _obj.DangerousRelease();
+                }
+            }
         }
 
         public string GetSource()
         {
             IntPtr __retval = default;
-            try
-            {
-                Marshal.ThrowExceptionForHR(_obj.Vftbl.GetSource_1(ThisPtr, &__retval));
-                return __retval != IntPtr.Zero ? Marshal.PtrToStringBSTR(__retval) : string.Empty;
+            bool success = false;
+            try
+            {
+                _obj.DangerousAddRef(ref success);
+                var thisPtr = _obj.DangerousGetPtr();
+                Marshal.ThrowExceptionForHR(_obj.Vftbl.GetSource_1(thisPtr, &__retval));
+                return __retval != IntPtr.Zero ? Marshal.PtrToStringBSTR(__retval) : string.Empty;
             }
-            finally
+            finally
             {
-                Marshal.FreeBSTR(__retval);
+                Marshal.FreeBSTR(__retval);
+                if (success)
+                {
+                    _obj.DangerousRelease();
+                }
             }
         }
 
         public string GetDescription()
         {
             IntPtr __retval = default;
-            try
-            {
-                Marshal.ThrowExceptionForHR(_obj.Vftbl.GetDescription_2(ThisPtr, &__retval));
-                return __retval != IntPtr.Zero ? Marshal.PtrToStringBSTR(__retval) : string.Empty;
+            bool success = false;
+            try
+            {
+                _obj.DangerousAddRef(ref success);
+                var thisPtr = _obj.DangerousGetPtr();
+                Marshal.ThrowExceptionForHR(_obj.Vftbl.GetDescription_2(thisPtr, &__retval));
+                return __retval != IntPtr.Zero ? Marshal.PtrToStringBSTR(__retval) : string.Empty;
             }
-            finally
+            finally
             {
-                Marshal.FreeBSTR(__retval);
+                Marshal.FreeBSTR(__retval);
+                if (success)
+                {
+                    _obj.DangerousRelease();
+                }
             }
         }
 
         public string GetHelpFile()
         {
             IntPtr __retval = default;
-            try
-            {
-                Marshal.ThrowExceptionForHR(_obj.Vftbl.GetHelpFile_3(ThisPtr, &__retval));
-                return __retval != IntPtr.Zero ? Marshal.PtrToStringBSTR(__retval) : string.Empty;
+            bool success = false;
+            try
+            {
+                _obj.DangerousAddRef(ref success);
+                var thisPtr = _obj.DangerousGetPtr();
+                Marshal.ThrowExceptionForHR(_obj.Vftbl.GetHelpFile_3(thisPtr, &__retval));
+                return __retval != IntPtr.Zero ? Marshal.PtrToStringBSTR(__retval) : string.Empty;
             }
-            finally
+            finally
             {
-                Marshal.FreeBSTR(__retval);
+                Marshal.FreeBSTR(__retval);
+                if (success)
+                {
+                    _obj.DangerousRelease();
+                }
             }
         }
 
         public string GetHelpFileContent()
-        {
+        {
             IntPtr __retval = default;
-            try
-            {
-                Marshal.ThrowExceptionForHR(_obj.Vftbl.GetHelpFileContent_4(ThisPtr, &__retval));
-                return __retval != IntPtr.Zero ? Marshal.PtrToStringBSTR(__retval) : string.Empty;
+            bool success = false;
+            try
+            {
+                _obj.DangerousAddRef(ref success);
+                var thisPtr = _obj.DangerousGetPtr();
+                Marshal.ThrowExceptionForHR(_obj.Vftbl.GetHelpFileContent_4(thisPtr, &__retval));
+                return __retval != IntPtr.Zero ? Marshal.PtrToStringBSTR(__retval) : string.Empty;
             }
-            finally
+            finally
             {
-                Marshal.FreeBSTR(__retval);
+                Marshal.FreeBSTR(__retval);
+                if (success)
+                {
+                    _obj.DangerousRelease();
+                }
             }
         }
     }
@@ -352,7 +395,7 @@ public struct Vftbl
         public static implicit operator ILanguageExceptionErrorInfo(IObjectReference obj) => (obj != null) ? new ILanguageExceptionErrorInfo(obj) : null;
         public static implicit operator ILanguageExceptionErrorInfo(ObjectReference<Vftbl> obj) => (obj != null) ? new ILanguageExceptionErrorInfo(obj) : null;
         protected readonly ObjectReference<Vftbl> _obj;
-        public IntPtr ThisPtr => _obj.ThisPtr;
+        public IntPtr ThisPtr => _obj.ThisPtr; 
         public ObjectReference<I> AsInterface<I>() => _obj.As<I>();
         public A As<A>() => _obj.AsType<A>();
         public ILanguageExceptionErrorInfo(IObjectReference obj) : this(obj.As<Vftbl>()) { }
@@ -364,17 +407,20 @@ public ILanguageExceptionErrorInfo(ObjectReference<Vftbl> obj)
         public IObjectReference GetLanguageException()
         {
             IntPtr __return_value__ = IntPtr.Zero;
-
+            bool success = false;
             try
             {
-                Marshal.ThrowExceptionForHR(_obj.Vftbl.GetLanguageException_0(ThisPtr, &__return_value__));
+                _obj.DangerousAddRef(ref success);
+                var thisPtr = _obj.DangerousGetPtr();
+                Marshal.ThrowExceptionForHR(_obj.Vftbl.GetLanguageException_0(thisPtr, &__return_value__));
                 return ObjectReference<global::WinRT.Interop.IUnknownVftbl>.Attach(ref __return_value__);
             }
             finally
             {
-                if (__return_value__ != IntPtr.Zero)
-                {
-                    (*(global::WinRT.Interop.IUnknownVftbl**)__return_value__)->Release(__return_value__);
+                MarshalInspectable<object>.DisposeAbi(__return_value__);
+                if (success)
+                {
+                    _obj.DangerousRelease();
                 }
             }
         }
@@ -435,6 +481,8 @@ private static int Do_Abi_InterfaceSupportsErrorInfo_0(IntPtr thisPtr, Guid* gui
         public static implicit operator ISupportErrorInfo(IObjectReference obj) => (obj != null) ? new ISupportErrorInfo(obj) : null;
         public static implicit operator ISupportErrorInfo(ObjectReference<Vftbl> obj) => (obj != null) ? new ISupportErrorInfo(obj) : null;
         protected readonly ObjectReference<Vftbl> _obj;
+        public IObjectReference ObjRef { get => _obj; }
+        [Obsolete]
         public IntPtr ThisPtr => _obj.ThisPtr;
         public ObjectReference<I> AsInterface<I>() => _obj.As<I>();
         public A As<A>() => _obj.AsType<A>();
@@ -445,8 +493,21 @@ public ISupportErrorInfo(ObjectReference<Vftbl> obj)
         }
 
         public bool InterfaceSupportsErrorInfo(Guid riid)
-        {
-            return _obj.Vftbl.InterfaceSupportsErrorInfo_0(ThisPtr, &riid) == 0;
+        {
+            bool success = false;
+            try
+            {
+                _obj.DangerousAddRef(ref success);
+                var thisPtr = _obj.DangerousGetPtr();
+                return _obj.Vftbl.InterfaceSupportsErrorInfo_0(thisPtr, &riid) == 0;
+            }
+            finally
+            {
+                if (success)
+                {
+                    _obj.DangerousRelease();
+                }
+            }
         }
     }
 
@@ -468,7 +529,6 @@ public struct Vftbl
         public static implicit operator IRestrictedErrorInfo(IObjectReference obj) => (obj != null) ? new IRestrictedErrorInfo(obj) : null;
         public static implicit operator IRestrictedErrorInfo(ObjectReference<Vftbl> obj) => (obj != null) ? new IRestrictedErrorInfo(obj) : null;
         protected readonly ObjectReference<Vftbl> _obj;
-        public IntPtr ThisPtr => _obj.ThisPtr;
         public ObjectReference<I> AsInterface<I>() => _obj.As<I>();
         public A As<A>() => _obj.AsType<A>();
         public IRestrictedErrorInfo(IObjectReference obj) : this(obj.As<Vftbl>()) { }
@@ -485,12 +545,16 @@ public void GetErrorDetails(
         {
             IntPtr _description = IntPtr.Zero;
             IntPtr _restrictedDescription = IntPtr.Zero;
-            IntPtr _capabilitySid = IntPtr.Zero;
+            IntPtr _capabilitySid = IntPtr.Zero;
+            bool success = false;
             try
-            {
+            {
+                _obj.DangerousAddRef(ref success);
+                var thisPtr = _obj.DangerousGetPtr();
+
                 fixed (int* pError = &error)
                 {
-                    Marshal.ThrowExceptionForHR(_obj.Vftbl.GetErrorDetails_0(ThisPtr, &_description, pError, &_restrictedDescription, &_capabilitySid));
+                    Marshal.ThrowExceptionForHR(_obj.Vftbl.GetErrorDetails_0(thisPtr, &_description, pError, &_restrictedDescription, &_capabilitySid));
                 }
                 description = _description != IntPtr.Zero ? Marshal.PtrToStringBSTR(_description) : string.Empty;
                 restrictedDescription = _restrictedDescription != IntPtr.Zero ? Marshal.PtrToStringBSTR(_restrictedDescription) : string.Empty;
@@ -500,21 +564,35 @@ public void GetErrorDetails(
             {
                 Marshal.FreeBSTR(_description);
                 Marshal.FreeBSTR(_restrictedDescription);
-                Marshal.FreeBSTR(_capabilitySid);
+                Marshal.FreeBSTR(_capabilitySid);
+
+                if (success)
+                {
+                    _obj.DangerousRelease();
+                }
             }
         }
 
         public string GetReference()
         {
-            IntPtr __retval = default;
+            IntPtr __retval = default;
+            bool success = false;
             try
-            {
-                Marshal.ThrowExceptionForHR(_obj.Vftbl.GetReference_1(ThisPtr, &__retval));
+            {
+                _obj.DangerousAddRef(ref success);
+                var thisPtr = _obj.DangerousGetPtr();
+
+                Marshal.ThrowExceptionForHR(_obj.Vftbl.GetReference_1(thisPtr, &__retval));
                 return __retval != IntPtr.Zero ? Marshal.PtrToStringBSTR(__retval) : string.Empty;
             }
             finally
             {
-                Marshal.FreeBSTR(__retval);
+                Marshal.FreeBSTR(__retval);
+
+                if (success)
+                {
+                    _obj.DangerousRelease();
+                }
             }
         }
     }