/// <summary>
/// Return the unmanaged C++ pointer from a <see cref="ICallbackable"/> instance.
/// </summary>
/// <typeparam name="TCallback">The type of the callback.</typeparam>
/// <param name="callback">The callback.</param>
/// <returns>A pointer to the unmanaged C++ object of the callback</returns>
public static IntPtr ToCallbackPtr <TCallback>(ICallbackable callback)
where TCallback : ICallbackable
{
// If callback is null, then return a null pointer
if (callback == null)
{
return(IntPtr.Zero);
}
// If callback is CppObject
if (callback is CppObject)
{
return(((CppObject)callback).NativePointer);
}
// Setup the shadow container in order to support multiple inheritance
var shadowContainer = callback.Shadow;
if (shadowContainer == null)
{
shadowContainer = new ShadowContainer();
shadowContainer.Initialize(callback);
}
return(shadowContainer.Find(typeof(TCallback)));
}
private static unsafe int GetIids(IntPtr thisPtr, int *iidCount, IntPtr *iids)
{
try
{
InspectableShadow shadow = ToShadow <InspectableShadow>(thisPtr);
IInspectable callback = (IInspectable)shadow.Callback;
ShadowContainer container = callback.Shadow;
int countGuids = container.Guids.Length;
// Copy GUIDs deduced from Callback
iids = (IntPtr *)Marshal.AllocCoTaskMem(IntPtr.Size * countGuids);
*iidCount = countGuids;
MemoryHelpers.CopyMemory((IntPtr)iids, new ReadOnlySpan <IntPtr>(container.Guids));
}
catch (Exception exception)
{
return((int)Result.GetResultFromException(exception));
}
return(Result.Ok.Code);
}
static Guid GetCallbackTypeGuid() => ShadowContainer.GuidFromType(typeof(TCallback));