Revert "Fix InvalidCastExceptions from RCW reuse (#833)" (#843)

This reverts commit 3f5dd34.
microsoft · May 13, 2021 · f84a3d5 · f84a3d5
1 parent 56b520f
commit f84a3d5
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Showing 4 changed files with 23 additions and 61 deletions.
diff --git a/src/Tests/UnitTest/TestComponentCSharp_Tests.cs b/src/Tests/UnitTest/TestComponentCSharp_Tests.cs
@@ -2253,15 +2253,7 @@ internal interface IInitializeWithWindow
 
         [Fact]
         unsafe public void TestComImports()
-        {
-            TestObject();
-            GCCollect();
-            Assert.Equal(0, ComImports.NumObjects);
-
-            TestImports();
-            GCCollect();
-            Assert.Equal(0, ComImports.NumObjects);
-
+        {
             static Object MakeObject()
             {
                 Assert.Equal(0, ComImports.NumObjects);
@@ -2282,25 +2274,25 @@ static Object MakeObject()
 
             static void TestImports()
             {
-                var (initializeWithWindow, windowNative) = MakeImports();
-
-                GCCollect();
+                var (initializeWithWindow, windowNative) = MakeImports();
+
+                GC.Collect();
+                GC.WaitForPendingFinalizers();
 
                 var hwnd = new IntPtr(0x12345678);
                 initializeWithWindow.Initialize(hwnd);
                 Assert.Equal(windowNative.WindowHandle, hwnd);
             }
 
-            static void GCCollect()
-            {
-                // Require multiple GC collects due to
-                // the final release is not done immediately.
-                for(int idx = 0; idx < 3; idx++)
-                {
-                    GC.Collect();
-                    GC.WaitForPendingFinalizers();
-                }
-            }
+            TestObject();
+            GC.Collect();
+            GC.WaitForPendingFinalizers();
+            Assert.Equal(0, ComImports.NumObjects);
+
+            TestImports();
+            GC.Collect();
+            GC.WaitForPendingFinalizers();
+            Assert.Equal(0, ComImports.NumObjects);
         }
 
         [Fact]

diff --git a/src/WinRT.Runtime/ComWrappersSupport.net5.cs b/src/WinRT.Runtime/ComWrappersSupport.net5.cs
@@ -99,12 +99,12 @@ public static T CreateRcwForComObject<T>(IntPtr ptr)
                 winrtObj.Resurrect();
             }
 
-            return rcw switch
-            {
-                ABI.System.Nullable<string> ns => (T)(object)ns.Value,
-                ABI.System.Nullable<Type> nt => (T)(object)nt.Value,
-                _ => (T)rcw
-            };
+            return rcw switch
+            {
+                ABI.System.Nullable<string> ns => (T)(object) ns.Value,
+                ABI.System.Nullable<Type> nt => (T)(object) nt.Value,
+                _ => (T) rcw
+            };
         }
 
         public static bool TryUnwrapObject(object o, out IObjectReference objRef)
@@ -143,7 +143,6 @@ public static object TryRegisterObjectForInterface(object obj, IntPtr thisPtr)
             if (target is IWinRTObject winrtObj)
             {
                 winrtObj.Resurrect();
-                winrtObj.NativeObject.MarkCleanupRCW();
             }
             return rcw;
         }
@@ -206,8 +205,7 @@ public unsafe static void Init(
             IntPtr inner,
             out IObjectReference objRef)
         {
-            objRef = ComWrappersSupport.GetObjectReferenceForInterface(isAggregation ? inner : newInstance);
-            objRef.MarkCleanupRCW();
+            objRef = ComWrappersSupport.GetObjectReferenceForInterface(isAggregation ? inner : newInstance);
 
             IntPtr referenceTracker;
             {
@@ -466,7 +464,6 @@ protected override object CreateObject(IntPtr externalComObject, CreateObjectFla
                 // on destruction as the CLR would do it.
                 winrtObj.NativeObject.ReleaseFromTrackerSource();
                 winrtObj.NativeObject.PreventReleaseFromTrackerSourceOnDispose = true;
-                winrtObj.NativeObject.MarkCleanupRCW();
             }
 
             return obj;

diff --git a/src/WinRT.Runtime/IWinRTObject.net5.cs b/src/WinRT.Runtime/IWinRTObject.net5.cs
@@ -169,7 +169,6 @@ internal void Resurrect()
         {
             if (NativeObject.Resurrect())
             {
-                NativeObject.MarkCleanupRCW();
                 foreach (var cached in QueryInterfaceCache)
                 {
                     cached.Value.Resurrect();

diff --git a/src/WinRT.Runtime/ObjectReference.cs b/src/WinRT.Runtime/ObjectReference.cs
@@ -17,8 +17,7 @@ public abstract class IObjectReference : IDisposable
         protected bool disposed;
         private readonly IntPtr _thisPtr;
         private object _disposedLock = new object();
-        private IntPtr _referenceTrackerPtr;
-        private byte _rcwCleanupCounter;
+        private IntPtr _referenceTrackerPtr;
 
         public IntPtr ThisPtr
         {
@@ -196,14 +195,7 @@ protected void ThrowIfDisposed()
         }
 
         public void Dispose()
-        {
-            // If this is the object reference associated with the RCW,
-            // defer dispose to after the RCW has been finalized for .NET 5.
-            if (!Cleanup)
-            {
-                return;
-            }
-
+        {
             Dispose(true);
             GC.SuppressFinalize(this);
         }
@@ -216,20 +208,6 @@ protected virtual void Dispose(bool disposing)
                 {
                     return;
                 }
-
-                // If the object reference is associated with the RCW, we need to
-                // defer the final release on the ThisPtr until after the RCW has been
-                // finalized and it has been removed from the ComWrappers cache.
-                // In .NET 6, there will be a new API for us to use, but until then
-                // in .NET 5, we defer the finalization of this object until it
-                // has reached Gen 2 by reregistering for finalization.
-                if(!Cleanup)
-                {
-                    _rcwCleanupCounter--;
-                    GC.ReRegisterForFinalize(this);
-                    return;
-                }
-
 #if DEBUG
                 if (BreakOnDispose && System.Diagnostics.Debugger.IsAttached)
                 {
@@ -330,10 +308,6 @@ private unsafe void DisposeTrackerSource()
                 ReferenceTracker.IUnknownVftbl.Release(ReferenceTrackerPtr);
             }
         }
-
-        internal void MarkCleanupRCW() => _rcwCleanupCounter = 2;
-
-        private bool Cleanup { get => _rcwCleanupCounter == 0; }
     }
 
     public class ObjectReference<T> : IObjectReference