Restore .NET Standard context callback logic

src/WinRT.Runtime/Context.cs

@@ -33,7 +33,25 @@ public unsafe static void CallInContext(IntPtr contextCallbackPtr, IntPtr contex
  return;
  }
 
+#if NET && CsWinRT_LANG_11_FEATURES
  IContextCallbackVftbl.ContextCallback(contextCallbackPtr, callback, onFailCallback);
+#else
+ ComCallData data = default;
+ var contextCallback = new ABI.WinRT.Interop.IContextCallback(ObjectReference<ABI.WinRT.Interop.IContextCallback.Vftbl>.FromAbi(contextCallbackPtr));
+
+ try
+ {
+ contextCallback.ContextCallback(_ =>
+ {
+ callback();
+ return 0;
+ }, &data, InterfaceIIDs.ICallbackWithNoReentrancyToApplicationSTA_IID, 5);
+ } 
+ catch(Exception)
+ {
+ onFailCallback?.Invoke();
+ }
+#endif
  }
 
  public static void DisposeContextCallback(IntPtr contextCallbackPtr)

src/WinRT.Runtime/Interop/IContextCallback.cs

@@ -2,7 +2,6 @@
 // Licensed under the MIT License.
 
 using System;
-using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 using WinRT;
 
@@ -17,23 +16,17 @@ internal struct ComCallData
  public IntPtr pUserDefined;
  }
 
-#if !(NET && CsWinRT_LANG_11_FEATURES)
- internal unsafe delegate int PFNCONTEXTCALL(ComCallData* data);
-#endif
-
+#if NET && CsWinRT_LANG_11_FEATURES
  internal unsafe struct IContextCallbackVftbl
  {
- public static readonly Guid IID_ICallbackWithNoReentrancyToApplicationSTA = new(0x0A299774, 0x3E4E, 0xFC42, 0x1D, 0x9D, 0x72, 0xCE, 0xE1, 0x05, 0xCA, 0x57);
-
  private global::WinRT.Interop.IUnknownVftbl IUnknownVftbl;
  private delegate* unmanaged[Stdcall]<IntPtr, IntPtr, ComCallData*, Guid*, int, IntPtr, int> ContextCallback_4;
 
  public static void ContextCallback(IntPtr contextCallbackPtr, Action callback, Action onFailCallback)
  {
  ComCallData comCallData;
  comCallData.dwDispid = 0;
- comCallData.dwReserved = 0;
-#if NET && CsWinRT_LANG_11_FEATURES
+ comCallData.dwReserved = 0;
 
  // Copy the callback into a local to make sure it really is a local that
  // gets marked as address taken, rather than something that could potentially
@@ -65,42 +58,63 @@ static int InvokeCallback(ComCallData* comCallData)
  return e.HResult;
  }
  }
-#else
- comCallData.pUserDefined = IntPtr.Zero;
-#endif
 
- Guid iid = IID_ICallbackWithNoReentrancyToApplicationSTA;
- int hresult;
-#if NET && CsWinRT_LANG_11_FEATURES
- hresult = (*(IContextCallbackVftbl**)contextCallbackPtr)->ContextCallback_4(
- contextCallbackPtr,
- (IntPtr)(delegate* unmanaged<ComCallData*, int>)&InvokeCallback,
- &comCallData,
- &iid,
- /* iMethod */ 5,
- IntPtr.Zero);
-#else
- PFNCONTEXTCALL nativeCallback = _ =>
- {
- callback();
- return 0;
- };
+ Guid iid = InterfaceIIDs.ICallbackWithNoReentrancyToApplicationSTA_IID;
 
- hresult = (*(IContextCallbackVftbl**)contextCallbackPtr)->ContextCallback_4(
+ int hresult = (*(IContextCallbackVftbl**)contextCallbackPtr)->ContextCallback_4(
  contextCallbackPtr,
- Marshal.GetFunctionPointerForDelegate(nativeCallback),
+ (IntPtr)(delegate* unmanaged<ComCallData*, int>)&InvokeCallback,
  &comCallData,
  &iid,
  /* iMethod */ 5,
  IntPtr.Zero);
-
- GC.KeepAlive(nativeCallback);
-#endif
 
  if (hresult < 0)
  {
  onFailCallback?.Invoke();
  }
  }
  }
+#else
+ internal unsafe delegate int PFNCONTEXTCALL(ComCallData* data);
+
+ [Guid("000001da-0000-0000-C000-000000000046")]
+ internal sealed unsafe class IContextCallback
+ {
+ internal static readonly Guid IID = InterfaceIIDs.IContextCallback_IID;
+
+ [Guid("000001da-0000-0000-C000-000000000046")]
+ public struct Vftbl
+ {
+ global::WinRT.Interop.IUnknownVftbl IUnknownVftbl;
+ private void* _ContextCallback;
+ public delegate* unmanaged[Stdcall]<IntPtr, IntPtr, ComCallData*, Guid*, int, IntPtr, int> ContextCallback_4
+ {
+ get => (delegate* unmanaged[Stdcall]<IntPtr, IntPtr, ComCallData*, Guid*, int, IntPtr, int>)_ContextCallback;
+ set => _ContextCallback = (void*)value;
+ }
+ }
+ public static ObjectReference<Vftbl> FromAbi(IntPtr thisPtr) => ObjectReference<Vftbl>.FromAbi(thisPtr);
+
+ public static implicit operator IContextCallback(IObjectReference obj) => (obj != null) ? new IContextCallback(obj) : null;
+ public static implicit operator IContextCallback(ObjectReference<Vftbl> obj) => (obj != null) ? new IContextCallback(obj) : null;
+ private 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 IContextCallback(IObjectReference obj) : this(obj.As<Vftbl>()) { }
+ public IContextCallback(ObjectReference<Vftbl> obj)
+ {
+ _obj = obj;
+ }
+
+ public unsafe void ContextCallback(PFNCONTEXTCALL pfnCallback, ComCallData* pParam, Guid riid, int iMethod)
+ {
+ var callback = Marshal.GetFunctionPointerForDelegate(pfnCallback);
+ var result = _obj.Vftbl.ContextCallback_4(ThisPtr, callback, pParam, &riid, iMethod, IntPtr.Zero);
+ GC.KeepAlive(pfnCallback);
+ Marshal.ThrowExceptionForHR(result);
+ }
+ }
+#endif
 }

src/cswinrt/strings/WinRT.cs

@@ -1122,6 +1122,7 @@ internal static class InterfaceIIDs
  internal static readonly Guid IAgileObject_IID = new Guid(new global::System.ReadOnlySpan<byte>(new byte[] { 0x94, 0x2B, 0xEA, 0x94, 0xCC, 0xE9, 0xE0, 0x49, 0xC0, 0xFF, 0xEE, 0x64, 0xCA, 0x8F, 0x5B, 0x90 }));
  internal static readonly Guid IMarshal_IID = new Guid(new global::System.ReadOnlySpan<byte>(new byte[] { 0x03, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x46 }));
  internal static readonly Guid IContextCallback_IID = new Guid(new global::System.ReadOnlySpan<byte>(new byte[] { 0xDA, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x46 }));
+ internal static readonly Guid ICallbackWithNoReentrancyToApplicationSTA_IID = new Guid(new global::System.ReadOnlySpan<byte>(new byte[] { 0x74, 0x97, 0x29, 0x0A, 0x4E, 0x3E, 0x42, 0xFC, 0x1D, 0x9D, 0x72, 0xCE, 0xE1, 0x05, 0xCA, 0x57 }));
 #else
  internal static readonly Guid IInspectable_IID = new(0xAF86E2E0, 0xB12D, 0x4c6a, 0x9C, 0x5A, 0xD7, 0xAA, 0x65, 0x10, 0x1E, 0x90);
  internal static readonly Guid IUnknown_IID = new(0, 0, 0, 0xC0, 0, 0, 0, 0, 0, 0, 0x46);
@@ -1131,6 +1132,7 @@ internal static class InterfaceIIDs
  internal static readonly Guid IAgileObject_IID = new(0x94ea2b94, 0xe9cc, 0x49e0, 0xc0, 0xff, 0xee, 0x64, 0xca, 0x8f, 0x5b, 0x90);
  internal static readonly Guid IMarshal_IID = new(0x00000003, 0, 0, 0xc0, 0, 0, 0, 0, 0, 0, 0x46);
  internal static readonly Guid IContextCallback_IID = new(0x000001da, 0, 0, 0xC0, 0, 0, 0, 0, 0, 0, 0x46);
+ internal static readonly Guid ICallbackWithNoReentrancyToApplicationSTA_IID = new(0x0A299774, 0x3E4E, 0xFC42, 0x1D, 0x9D, 0x72, 0xCE, 0xE1, 0x05, 0xCA, 0x57);
 #endif
  }
 }