class PathMatcher

class PathMatcher implements PathMatcherInterface {
    
    /**
     * Whether the current page is the front page.
     *
     * @var bool
     */
    protected $isCurrentFrontPage;
    
    /**
     * The default front page.
     *
     * @var string
     */
    protected $frontPage;
    
    /**
     * The cache of regular expressions.
     *
     * @var array
     */
    protected $regexes;
    
    /**
     * The config factory service.
     *
     * @var \Drupal\Core\Config\ConfigFactoryInterface
     */
    protected $configFactory;
    
    /**
     * The current route match.
     *
     * @var \Drupal\Core\Routing\RouteMatchInterface
     */
    protected $routeMatch;
    
    /**
     * Creates a new PathMatcher.
     *
     * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
     *   The config factory.
     * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
     *   The current route match.
     */
    public function __construct(ConfigFactoryInterface $config_factory, RouteMatchInterface $route_match) {
        $this->configFactory = $config_factory;
        $this->routeMatch = $route_match;
    }
    
    /**
     * {@inheritdoc}
     */
    public function matchPath($path, $patterns) {
        if (!isset($this->regexes[$patterns])) {
            // Convert path settings to a regular expression.
            $to_replace = [
                // Replace newlines with a logical 'or'.
'/(\\r\\n?|\\n)/',
                // Quote asterisks.
'/\\\\\\*/',
                // Quote <front> keyword.
'/(^|\\|)\\\\<front\\\\>($|\\|)/',
            ];
            $replacements = [
                '|',
                '.*',
                '\\1' . preg_quote($this->getFrontPagePath(), '/') . '\\2',
            ];
            $patterns_quoted = preg_quote($patterns, '/');
            $this->regexes[$patterns] = '/^(' . preg_replace($to_replace, $replacements, $patterns_quoted) . ')$/';
        }
        return (bool) preg_match($this->regexes[$patterns], $path);
    }
    
    /**
     * {@inheritdoc}
     */
    public function isFrontPage() {
        // Cache the result as this is called often.
        if (!isset($this->isCurrentFrontPage)) {
            $this->isCurrentFrontPage = FALSE;
            // Ensure that the code can also be executed when there is no active
            // route match, like on exception responses.
            if ($this->routeMatch
                ->getRouteName()) {
                $url = Url::fromRouteMatch($this->routeMatch);
                $this->isCurrentFrontPage = $url->getRouteName() && '/' . $url->getInternalPath() === $this->getFrontPagePath();
            }
        }
        return $this->isCurrentFrontPage;
    }
    
    /**
     * Gets the current front page path.
     *
     * @return string
     *   The front page path.
     */
    protected function getFrontPagePath() {
        // Lazy-load front page config.
        if (!isset($this->frontPage)) {
            $this->frontPage = $this->configFactory
                ->get('system.site')
                ->get('page.front');
        }
        return $this->frontPage;
    }

}