/// <summary>
/// Returns whether the IUnknown* is a free-threaded COM object
/// </summary>
/// <param name="pUnknown"></param>
internal static unsafe bool IsFreeThreaded(IntPtr pUnknown)
{
//
// Does it support IAgileObject?
//
IntPtr pAgileObject = McgMarshal.ComQueryInterfaceNoThrow(pUnknown, ref Interop.COM.IID_IAgileObject);
if (pAgileObject != default(IntPtr))
{
// Anything that implements IAgileObject is considered to be free-threaded
// NOTE: This doesn't necessarily mean that the object is free-threaded - it only means
// we BELIEVE it is free-threaded
McgMarshal.ComRelease_StdCall(pAgileObject);
return(true);
}
IntPtr pMarshal = McgMarshal.ComQueryInterfaceNoThrow(pUnknown, ref Interop.COM.IID_IMarshal);
if (pMarshal == default(IntPtr))
{
return(false);
}
try
{
//
// Check the un-marshaler
//
Interop.COM.__IMarshal *pIMarshalNativePtr = (Interop.COM.__IMarshal *)(void *) pMarshal;
fixed(Guid *pGuid = &Interop.COM.IID_IUnknown)
{
Guid clsid;
int hr = CalliIntrinsics.StdCall__int(
pIMarshalNativePtr->vtbl->pfnGetUnmarshalClass,
new IntPtr(pIMarshalNativePtr),
pGuid,
default(IntPtr),
(uint)Interop.COM.MSHCTX.MSHCTX_INPROC,
default(IntPtr),
(uint)Interop.COM.MSHLFLAGS.MSHLFLAGS_NORMAL,
&clsid);
if (hr >= 0 && InteropExtensions.GuidEquals(ref clsid, ref Interop.COM.CLSID_InProcFreeMarshaler))
{
// The un-marshaller is indeed the unmarshaler for the FTM so this object
// is free threaded.
return(true);
}
}
return(false);
}
finally
{
McgMarshal.ComRelease_StdCall(pMarshal);
}
}