// simply check if a COM object supports a particular COM interface
// (without doing any casting by the CLR, which does much more than this under the covers)
public static bool DoesComObjPtrSupportInterface <T>(IntPtr comObjPtr)
{
var iid = typeof(T).GUID;
var hr = RdMarshal.QueryInterface(comObjPtr, ref iid, out var outInterfacePtr);
if (!ComHelper.HRESULT_FAILED(hr))
{
RdMarshal.Release(outInterfacePtr);
return(true);
}
return(false);
}
/// <summary>
/// Constructor
/// </summary>
/// <param name="outerObject">The object that needs interface requests filtered</param>
/// <param name="queryForType">determines whether we call QueryInterface for the interface or not</param>
/// <remarks>if the passed in outerObject is known to point to the correct vtable for the interface, then queryForType can be false</remarks>
/// <returns>if outerObject is IntPtr.Zero, then a null wrapper, else an aggregated wrapper</returns>
public RestrictComInterfaceByAggregation(IntPtr outerObject, bool queryForType = true)
{
if (queryForType)
{
var iid = typeof(T).GUID;
if (ComHelper.HRESULT_FAILED(RdMarshal.QueryInterface(outerObject, ref iid, out _outerObject)))
{
// allow null wrapping here
return;
}
}
else
{
_outerObject = outerObject;
RdMarshal.AddRef(_outerObject);
}
var clrAggregator = RdMarshal.CreateAggregatedObject(_outerObject, this);
WrappedObject = (T)RdMarshal.GetObjectForIUnknown(clrAggregator); // when this CCW object gets released, it will free the aggObjInner (well, after GC)
RdMarshal.Release(clrAggregator); // _wrappedObject holds a reference to this now
}
