Searching for subfolders

gistfile1.m

- (NSNumber *)directoryContainsASubfolder:(NSURL *)directoryURL error:(NSError **)error;
{
    NSArray *contents = [[NSFileManager defaultManager]
                         contentsOfDirectoryAtURL:directoryURL
                         includingPropertiesForKeys:nil
                         options:NSDirectoryEnumerationSkipsHiddenFiles
                         error:error];
    
    if (!contents) return nil;
    
    for (NSURL *aURL in contents)
    {
        // Ignore failures for resource values. Such a failure makes it incredibly unlikely
        // the URL is a folder we can actually *list*
        NSNumber *isDirectory;
        if ([aURL getResourceValue:&isDirectory forKey:NSURLIsDirectory error:error] &&
            [isDirectory boolValue])
        {
            // If know it's a directory, but don't know if it's a package, treat as a folder
            NSNumber *isPackage;
            if (![aURL getResourceValue:&isPackage forKey:NSURLIsPackage error:error] ||
                ![isPackage boolValue])
            {
                // Once we find a non-package directory, that's good enough
                return @YES;
            }
        }
    }
    
    return @NO;
}