Caculate a folder size

CaculateFolderSize.m

NSArray *filesArray = [[NSFileManager defaultManager] subpathsOfDirectoryAtPath:cachePath error:&error];
NSEnumerator *filesEnumerator = [filesArray objectEnumerator];
NSString *fileName;
unsigned long long int fileSize = 0;
    
while (fileName = [filesEnumerator nextObject]) {
    NSString *filePath = [cachePath stringByAppendingPathComponent:fileName];
    NSDictionary *fileDictionary = [fm attributesOfItemAtPath:filePath error:&error];
    fileSize += [fileDictionary fileSize];
}