IsItCarbonWindow or IsItCocoaWindow?!

I've found the following implementation:

@class NSCarbonWindow;

bool IsItACocoaWindow (WindowRef window) 
{
    NSWindow* cocoaWindow = [[NSWindow alloc] initWithWindowRef:window];
    BOOL carbon = [[cocoaWindow class]isSubclassOfClass:[NSCarbonWindow class]];
    [cocoaWindow release];
 return !carbon;
}


bool IsItACarbonWindow (WindowRef window) 
{
 /* This one is a pure carbon function but it's a bit fragile, as for example in Leopard it actually returns: com.apple.hitoolbox.window.viewadapter */
 CFStringRef classid = HIObjectCopyClassID ((HIObjectRef) window);
 bool cocoa = (CFStringCompare (CFSTR ("com.apple.hitoolbox.window.external"), classid, 0) == kCFCompareEqualTo) ||
(CFStringCompare (CFSTR ("com.apple.hitoolbox.window. viewadapter"), classid, 0) == kCFCompareEqualTo);
 CFRelease (classid);
 return !cocoa;
}

It's also interesting to note that this can work because in case of the CocoaWindow the initWithWindowRef method will return the original window object for Cocoa objects. That is:

window == [[NSWindow alloc] initWithWindowRef: [window windowRef]];