/**
* Extracts the URL from a CSS URL value.
*
* @param string $url
* @return string
*/
public static function extractUrl($url)
{
if (is_string($url)) {
// Extract the URL from a given CSS URL value|string
//
// Examples:
// - "http://www.example.com"
// - 'http://www.example.com'
// - url("http://www.example.com")
// - url( 'http://www.example.com' )
// - url(http://www.example.com)
// - url( http://www.example.com )
// - url("http://www.example.com?escape=\"escape\"")
//
// "Parentheses, whitespace characters, single quotes (') and double quotes (") appearing in a URL must be
// escaped with a backslash so that the resulting value is a valid URL token"
$url = Placeholder::replaceStringPlaceholders($url);
$url = preg_replace('/^url\\(|\\)$/', '', $url);
$url = str_replace(["\\(", "\\)", "\\ ", "\\'", "\\\""], ["(", ")", " ", "'", "\""], $url);
$url = preg_replace('/^(["\'])(.*)\\g{1}$/', '\\2', $url);
$url = urldecode($url);
return $url;
} else {
throw new \InvalidArgumentException("Invalid type '" . gettype($url) . "' for argument 'url' given.");
}
}
