Sprockets\Filter\Minifier\Css::__invoke PHP Метод

    public function __invoke($files, $content)
    {
        //@todo md5 thousands of lines is stupid, what can I do ?
        $cache_file = $this->getCacheDir(md5($content) . '|css', __CLASS__);
        if (file_exists($css_cache_file = str_replace('.css', '.minified.css', $cache_file))) {
            return file_get_contents($css_cache_file);
        }
        if (!file_exists($cache_file)) {
            file_put_contents($cache_file, $content);
        }
        $out = $this->processNode(array('clean-css/bin/cleancss', $cache_file, '-o', $css_cache_file));
        if (!file_exists($css_cache_file)) {
            echo "Clean-CSS Minification Error<pre>" . str_replace($cache_file, $css_cache_file, $out) . "</pre>";
            @unlink($log);
            exit;
        }
        return file_get_contents($css_cache_file);
    }