Jetpack::absolutize_css_urls PHP Method

    public static function absolutize_css_urls($css, $css_file_url)
    {
        $pattern = '#url\\((?P<path>[^)]*)\\)#i';
        $css_dir = dirname($css_file_url);
        $p = parse_url($css_dir);
        $domain = sprintf('%1$s//%2$s%3$s%4$s', isset($p['scheme']) ? "{$p['scheme']}:" : '', isset($p['user'], $p['pass']) ? "{$p['user']}:{$p['pass']}@" : '', $p['host'], isset($p['port']) ? ":{$p['port']}" : '');
        if (preg_match_all($pattern, $css, $matches, PREG_SET_ORDER)) {
            $find = $replace = array();
            foreach ($matches as $match) {
                $url = trim($match['path'], "'\" \t");
                // If this is a data url, we don't want to mess with it.
                if ('data:' === substr($url, 0, 5)) {
                    continue;
                }
                // If this is an absolute or protocol-agnostic url,
                // we don't want to mess with it.
                if (preg_match('#^(https?:)?//#i', $url)) {
                    continue;
                }
                switch (substr($url, 0, 1)) {
                    case '/':
                        $absolute = $domain . $url;
                        break;
                    default:
                        $absolute = $css_dir . '/' . $url;
                }
                $find[] = $match[0];
                $replace[] = sprintf('url("%s")', $absolute);
            }
            $css = str_replace($find, $replace, $css);
        }
        return $css;
    }

 /**
  * Maybe inlines a stylesheet.
  *
  * If you'd like to inline a stylesheet instead of printing a link to it,
  * wp_style_add_data( 'handle', 'jetpack-inline', true );
  *
  * Attached to `style_loader_tag` filter.
  *
  * @param string $tag The tag that would link to the external asset.
  * @param string $handle The registered handle of the script in question.
  *
  * @return string
  */
 public static function maybe_inline_style($tag, $handle)
 {
     global $wp_styles;
     $item = $wp_styles->registered[$handle];
     if (!isset($item->extra['jetpack-inline']) || !$item->extra['jetpack-inline']) {
         return $tag;
     }
     if (preg_match('# href=\'([^\']+)\' #i', $tag, $matches)) {
         $href = $matches[1];
         // Strip off query string
         if ($pos = strpos($href, '?')) {
             $href = substr($href, 0, $pos);
         }
         // Strip off fragment
         if ($pos = strpos($href, '#')) {
             $href = substr($href, 0, $pos);
         }
     } else {
         return $tag;
     }
     $plugins_dir = plugin_dir_url(JETPACK__PLUGIN_FILE);
     if ($plugins_dir !== substr($href, 0, strlen($plugins_dir))) {
         return $tag;
     }
     // If this stylesheet has a RTL version, and the RTL version replaces normal...
     if (isset($item->extra['rtl']) && 'replace' === $item->extra['rtl'] && is_rtl()) {
         // And this isn't the pass that actually deals with the RTL version...
         if (false === strpos($tag, " id='{$handle}-rtl-css' ")) {
             // Short out, as the RTL version will deal with it in a moment.
             return $tag;
         }
     }
     $file = JETPACK__PLUGIN_DIR . substr($href, strlen($plugins_dir));
     $css = Jetpack::absolutize_css_urls(file_get_contents($file), $href);
     if ($css) {
         $tag = "<!-- Inline {$item->handle} -->\r\n";
         if (empty($item->extra['after'])) {
             wp_add_inline_style($handle, $css);
         } else {
             array_unshift($item->extra['after'], $css);
             wp_style_add_data($handle, 'after', $item->extra['after']);
         }
     }
     return $tag;
 }