海神

因为iphone上面只能获取文件夹节点的大小，不能获取占磁盘的大小，只能通过遍历所有文件来计算，这样计算的结果可能跟在finder中看到的结果有一点出入。返回的结果以字节计算。

- (unsigned long long) folderSize:(NSString *)folder {
    NSFileManager *_manager = [NSFileManager defaultManager];
    NSArray *_cacheFileList;
    NSEnumerator *_cacheEnumerator;
    NSString *_cacheFilePath;
    unsigned long long _cacheFolderSize = 0;

    _cacheFileList = [_manager subpathsAtPath:folder];
    _cacheEnumerator = [_cacheFileList objectEnumerator];
    while (_cacheFilePath = [_cacheEnumerator nextObject]) {
        NSDictionary *_cacheFileAttributes = [_manager attributesOfItemAtPath:[folder stringByAppendingPathComponent:_cacheFilePath] error:nil];
        _cacheFolderSize += [_cacheFileAttributes fileSize];
    }

    return _cacheFolderSize;
}