A8C_Files::filter_unique_filename PHP Method

    public function filter_unique_filename($filename, $ext, $dir, $unique_filename_callback)
    {
        if ('.tmp' === $ext || '/tmp/' === $dir) {
            return $filename;
        }
        $ext = strtolower($ext);
        $filename = $this->_sanitize_filename($filename, $ext);
        $check = $this->_check_uniqueness_with_backend($filename);
        if (200 == $check['http_code']) {
            $obj = json_decode($check['content']);
            if (isset($obj->filename) && basename($obj->filename) != basename($post_url)) {
                $filename = $obj->filename;
            }
        }
        return $filename;
    }