Fix for aggregated tear off scenarios (#870)

microsoft · Jun 11, 2021 · 9154452 · 9154452
1 parent d4a60fd
commit 9154452
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Showing 3 changed files with 20 additions and 6 deletions.
diff --git a/src/WinRT.Runtime/MatchingRefApiCompatBaseline.net5.0.txt b/src/WinRT.Runtime/MatchingRefApiCompatBaseline.net5.0.txt
@@ -5,4 +5,5 @@ MembersMustExist : Member 'public void WinRT.ComWrappersSupport.RegisterObjectFo
 MembersMustExist : Member 'protected void WinRT.IObjectReference.AddRef(System.Boolean)' does not exist in the reference but it does exist in the implementation.
 TypesMustExist : Type 'WinRT.Interop.IWeakReference' does not exist in the reference but it does exist in the implementation.
 TypesMustExist : Type 'WinRT.Interop.IWeakReferenceSource' does not exist in the reference but it does exist in the implementation.
-Total Issues: 6
+MembersMustExist : Member 'public System.Int32 WinRT.IObjectReference.TryAs(System.Guid, System.IntPtr)' does not exist in the reference but it does exist in the implementation.
+Total Issues: 7
diff --git a/src/WinRT.Runtime/ObjectReference.cs b/src/WinRT.Runtime/ObjectReference.cs
@@ -168,6 +168,23 @@ public virtual unsafe int TryAs<T>(Guid iid, out ObjectReference<T> objRef)
                 objRef.ReferenceTrackerPtr = ReferenceTrackerPtr;
             }
             return hr;
+        }
+
+        // Used only as part of the GetInterface implementation where the
+        // result is an reference passed across the ABI and doesn't need to
+        // be tracked as an internal reference.  This is separate to handle
+        // tear off aggregate scenario where releasing an reference can end up
+        // deleting the tear off interface.
+        public virtual unsafe int TryAs(Guid iid, out IntPtr ppv)
+        {
+            ppv = IntPtr.Zero;
+            ThrowIfDisposed();
+            int hr = VftblIUnknown.QueryInterface(ThisPtr, ref iid, out IntPtr thatPtr);
+            if (hr >= 0)
+            {
+                ppv = thatPtr;
+            }
+            return hr;
         }
 
         public unsafe IObjectReference As(Guid iid) => As<IUnknownVftbl>(iid);

diff --git a/src/cswinrt/code_writers.h b/src/cswinrt/code_writers.h
@@ -5135,14 +5135,10 @@ if (IsOverridableInterface(iid) || typeof(global::WinRT.IInspectable).GUID == ii
 return global::System.Runtime.InteropServices.CustomQueryInterfaceResult.NotHandled;
 }
 
-if (%.TryAs<IUnknownVftbl>(iid, out ObjectReference<IUnknownVftbl> objRef) >= 0)
+if (%.TryAs(iid, out ppv) >= 0)
 {
-using (objRef)
-{
-ppv = objRef.GetRef();
 return global::System.Runtime.InteropServices.CustomQueryInterfaceResult.Handled;
 }
-}
 
 return global::System.Runtime.InteropServices.CustomQueryInterfaceResult.NotHandled;
 })",