class Url

class Url implements TrustedCallbackInterface {
    use DependencySerializationTrait;
    
    /**
     * The URL generator.
     *
     * @var \Drupal\Core\Routing\UrlGeneratorInterface
     */
    protected $urlGenerator;
    
    /**
     * The unrouted URL assembler.
     *
     * @var \Drupal\Core\Utility\UnroutedUrlAssemblerInterface
     */
    protected $urlAssembler;
    
    /**
     * The access manager.
     *
     * @var \Drupal\Core\Access\AccessManagerInterface
     */
    protected $accessManager;
    
    /**
     * The route name.
     *
     * @var string
     */
    protected $routeName;
    
    /**
     * The route parameters.
     *
     * @var array
     */
    protected $routeParameters = [];
    
    /**
     * The URL options.
     *
     * See \Drupal\Core\Url::fromUri() for details on the options.
     *
     * @var array
     */
    protected $options = [];
    
    /**
     * Indicates whether this object contains an external URL.
     *
     * @var bool
     */
    protected $external = FALSE;
    
    /**
     * Indicates whether this URL is for a URI without a Drupal route.
     *
     * @var bool
     */
    protected $unrouted = FALSE;
    
    /**
     * The non-route URI.
     *
     * Only used if self::$unrouted is TRUE.
     *
     * @var string
     */
    protected $uri;
    
    /**
     * Stores the internal path, if already requested by getInternalPath().
     *
     * @var string
     */
    protected $internalPath;
    
    /**
     * Constructs a new Url object.
     *
     * In most cases, use Url::fromRoute() or Url::fromUri() rather than
     * constructing Url objects directly in order to avoid ambiguity and make your
     * code more self-documenting.
     *
     * @param string $route_name
     *   The name of the route
     * @param array $route_parameters
     *   (optional) An associative array of parameter names and values.
     * @param array $options
     *   See \Drupal\Core\Url::fromUri() for details.
     *
     * @see static::fromRoute()
     * @see static::fromUri()
     *
     * @todo Update this documentation for non-routed URIs in
     *   https://www.drupal.org/node/2346787
     */
    public function __construct($route_name, $route_parameters = [], $options = []) {
        $this->routeName = $route_name;
        $this->routeParameters = $route_parameters;
        $this->options = $options;
    }
    
    /**
     * Creates a new Url object for a URL that has a Drupal route.
     *
     * This method is for URLs that have Drupal routes (that is, most pages
     * generated by Drupal). For non-routed local URIs relative to the base
     * path (like robots.txt) use Url::fromUri() with the base: scheme.
     *
     * @param string $route_name
     *   The name of the route
     * @param array $route_parameters
     *   (optional) An associative array of route parameter names and values.
     * @param array $options
     *   See \Drupal\Core\Url::fromUri() for details.
     *
     * @return static
     *   A new Url object for a routed (internal to Drupal) URL.
     *
     * @see \Drupal\Core\Url::fromUserInput()
     * @see \Drupal\Core\Url::fromUri()
     */
    public static function fromRoute($route_name, $route_parameters = [], $options = []) {
        return new static($route_name, $route_parameters, $options);
    }
    
    /**
     * Creates a new URL object from a route match.
     *
     * @param \Drupal\Core\Routing\RouteMatchInterface $route_match
     *   The route match.
     *
     * @return static
     */
    public static function fromRouteMatch(RouteMatchInterface $route_match) {
        if ($route_match->getRouteObject()) {
            return new static($route_match->getRouteName(), $route_match->getRawParameters()
                ->all());
        }
        else {
            throw new \InvalidArgumentException('Route required');
        }
    }
    
    /**
     * Creates a Url object for a relative URI reference submitted by user input.
     *
     * Use this method to create a URL for user-entered paths that may or may not
     * correspond to a valid Drupal route.
     *
     * @param string $user_input
     *   User input for a link or path. The first character must be one of the
     *   following characters:
     *   - '/': A path within the current site. This path might be to a Drupal
     *     route (e.g., '/admin'), to a file (e.g., '/README.txt'), or to
     *     something processed by a non-Drupal script (e.g.,
     *     '/not/a/drupal/page'). If the path matches a Drupal route, then the
     *     URL generation will include Drupal's path processors (e.g.,
     *     language-prefixing and aliasing). Otherwise, the URL generation will
     *     just append the passed-in path to Drupal's base path.
     *   - '?': A query string for the current page or resource.
     *   - '#': A fragment (jump-link) on the current page or resource.
     *   This helps reduce ambiguity for user-entered links and paths, and
     *   supports user interfaces where users may normally use auto-completion
     *   to search for existing resources, but also may type one of these
     *   characters to link to (e.g.) a specific path on the site.
     *   (With regard to the URI specification, the user input is treated as a
     *   @link https://tools.ietf.org/html/rfc3986#section-4.2 relative URI reference @endlink
     *   where the relative part is of type
     *   @link https://tools.ietf.org/html/rfc3986#section-3.3 path-abempty @endlink.)
     * @param array $options
     *   (optional) An array of options. See Url::fromUri() for details.
     *
     * @return static
     *   A new Url object based on user input.
     *
     * @throws \InvalidArgumentException
     *   Thrown when the user input does not begin with one of the following
     *   characters: '/', '?', or '#'.
     */
    public static function fromUserInput($user_input, $options = []) {
        // Ensuring one of these initial characters also enforces that what is
        // passed is a relative URI reference rather than an absolute URI,
        // because these are URI reserved characters that a scheme name may not
        // start with.
        if (strpos($user_input, '/') !== 0 && strpos($user_input, '#') !== 0 && strpos($user_input, '?') !== 0) {
            throw new \InvalidArgumentException("The user-entered string '{$user_input}' must begin with a '/', '?', or '#'.");
        }
        // fromUri() requires an absolute URI, so prepend the appropriate scheme
        // name.
        return static::fromUri('internal:' . $user_input, $options);
    }
    
    /**
     * Creates a new Url object from a URI.
     *
     * This method is for generating URLs for URIs that:
     * - do not have Drupal routes: both external URLs and unrouted local URIs
     *   like base:robots.txt
     * - do have a Drupal route but have a custom scheme to simplify linking.
     *   Currently, there is only the entity: scheme (This allows URIs of the
     *   form entity:{entity_type}/{entity_id}. For example: entity:node/1
     *   resolves to the entity.node.canonical route with a node parameter of 1.)
     *
     * For URLs that have Drupal routes (that is, most pages generated by Drupal),
     * use Url::fromRoute().
     *
     * @param string $uri
     *   The URI of the resource including the scheme. For user input that may
     *   correspond to a Drupal route, use internal: for the scheme. For paths
     *   that are known not to be handled by the Drupal routing system (such as
     *   static files), use base: for the scheme to get a link relative to the
     *   Drupal base path (like the <base> HTML element). For a link to an entity
     *   you may use entity:{entity_type}/{entity_id} URIs. The internal: scheme
     *   should be avoided except when processing actual user input that may or
     *   may not correspond to a Drupal route. Normally use Url::fromRoute() for
     *   code linking to any Drupal page.
     * @param array $options
     *   (optional) An associative array of additional URL options, with the
     *   following elements:
     *   - 'query': An array of query key/value-pairs (without any URL-encoding)
     *     to append to the URL.
     *   - 'fragment': A fragment identifier (named anchor) to append to the URL.
     *     Do not include the leading '#' character.
     *   - 'absolute': Defaults to FALSE. Whether to force the output to be an
     *     absolute link (beginning with http:). Useful for links that will be
     *     displayed outside the site, such as in an RSS feed.
     *   - 'attributes': An associative array of HTML attributes that will be
     *     added to the anchor tag if you use the \Drupal\Core\Link class to make
     *     the link.
     *   - 'language': An optional language object used to look up the alias
     *     for the URL. If $options['language'] is omitted, it defaults to the
     *     current language for the language type LanguageInterface::TYPE_URL.
     *   - 'https': Whether this URL should point to a secure location. If not
     *     defined, the current scheme is used, so the user stays on HTTP or HTTPS
     *     respectively. TRUE enforces HTTPS and FALSE enforces HTTP.
     *
     * @return static
     *   A new Url object with properties depending on the URI scheme. Call the
     *   access() method on this to do access checking.
     *
     * @throws \InvalidArgumentException
     *   Thrown when the passed in path has no scheme.
     *
     * @see \Drupal\Core\Url::fromRoute()
     * @see \Drupal\Core\Url::fromUserInput()
     */
    public static function fromUri($uri, $options = []) {
        // parse_url() incorrectly parses base:number/... as hostname:port/...
        // and not the scheme. Prevent that by prefixing the path with a slash.
        if (preg_match('/^base:\\d/', $uri)) {
            $uri = str_replace('base:', 'base:/', $uri);
        }
        $uri_parts = parse_url($uri);
        if ($uri_parts === FALSE) {
            throw new \InvalidArgumentException("The URI '{$uri}' is malformed.");
        }
        // We support protocol-relative URLs.
        if (strpos($uri, '//') === 0) {
            $uri_parts['scheme'] = '';
        }
        elseif (empty($uri_parts['scheme'])) {
            throw new \InvalidArgumentException("The URI '{$uri}' is invalid. You must use a valid URI scheme.");
        }
        $uri_parts += [
            'path' => '',
        ];
        // Discard empty fragment in $options for consistency with parse_url().
        if (isset($options['fragment']) && strlen($options['fragment']) == 0) {
            unset($options['fragment']);
        }
        // Extract query parameters and fragment and merge them into $uri_options,
        // but preserve the original $options for the fallback case.
        $uri_options = $options;
        if (isset($uri_parts['fragment']) && $uri_parts['fragment'] !== '') {
            $uri_options += [
                'fragment' => $uri_parts['fragment'],
            ];
            unset($uri_parts['fragment']);
        }
        if (!empty($uri_parts['query'])) {
            $uri_query = [];
            parse_str($uri_parts['query'], $uri_query);
            $uri_options['query'] = isset($uri_options['query']) ? $uri_options['query'] + $uri_query : $uri_query;
            unset($uri_parts['query']);
        }
        if ($uri_parts['scheme'] === 'entity') {
            $url = static::fromEntityUri($uri_parts, $uri_options, $uri);
        }
        elseif ($uri_parts['scheme'] === 'internal') {
            $url = static::fromInternalUri($uri_parts, $uri_options);
        }
        elseif ($uri_parts['scheme'] === 'route') {
            $url = static::fromRouteUri($uri_parts, $uri_options, $uri);
        }
        else {
            $url = new static($uri, [], $options);
            if ($uri_parts['scheme'] !== 'base') {
                $url->external = TRUE;
                $url->setOption('external', TRUE);
            }
            $url->setUnrouted();
        }
        return $url;
    }
    
    /**
     * Create a new Url object for entity URIs.
     *
     * @param array $uri_parts
     *   Parts from a URI of the form entity:{entity_type}/{entity_id} as from
     *   parse_url().
     * @param array $options
     *   An array of options, see \Drupal\Core\Url::fromUri() for details.
     * @param string $uri
     *   The original entered URI.
     *
     * @return static
     *   A new Url object for an entity's canonical route.
     *
     * @throws \InvalidArgumentException
     *   Thrown if the entity URI is invalid.
     */
    protected static function fromEntityUri(array $uri_parts, array $options, $uri) {
        [
            $entity_type_id,
            $entity_id,
        ] = explode('/', $uri_parts['path'], 2);
        if ($uri_parts['scheme'] != 'entity' || $entity_id === '') {
            throw new \InvalidArgumentException("The entity URI '{$uri}' is invalid. You must specify the entity id in the URL. e.g., entity:node/1 for loading the canonical path to node entity with id 1.");
        }
        return new static("entity.{$entity_type_id}.canonical", [
            $entity_type_id => $entity_id,
        ], $options);
    }
    
    /**
     * Creates a new Url object for 'internal:' URIs.
     *
     * Important note: the URI minus the scheme can NOT simply be validated by a
     * \Drupal\Core\Path\PathValidatorInterface implementation. The semantics of
     * the 'internal:' URI scheme are different:
     * - PathValidatorInterface accepts paths without a leading slash (e.g.
     *   'node/add') as well as 2 special paths: '<front>' and '<none>', which are
     *   mapped to the correspondingly named routes.
     * - 'internal:' URIs store paths with a leading slash that represents the
     *   root — i.e. the front page — (e.g. 'internal:/node/add'), and doesn't
     *   have any exceptions.
     *
     * To clarify, a few examples of path plus corresponding 'internal:' URI:
     * - 'node/add' -> 'internal:/node/add'
     * - 'node/add?foo=bar' -> 'internal:/node/add?foo=bar'
     * - 'node/add#kitten' -> 'internal:/node/add#kitten'
     * - '<front>' -> 'internal:/'
     * - '<front>foo=bar' -> 'internal:/?foo=bar'
     * - '<front>#kitten' -> 'internal:/#kitten'
     * - '<none>' -> 'internal:'
     * - '<none>foo=bar' -> 'internal:?foo=bar'
     * - '<none>#kitten' -> 'internal:#kitten'
     *
     * Therefore, when using a PathValidatorInterface to validate 'internal:'
     * URIs, we must map:
     * - 'internal:' (path component is '')  to the special '<none>' path
     * - 'internal:/' (path component is '/') to the special '<front>' path
     * - 'internal:/some-path' (path component is '/some-path') to 'some-path'
     *
     * @param array $uri_parts
     *   Parts from a URI of the form internal:{path} as from parse_url().
     * @param array $options
     *   An array of options, see \Drupal\Core\Url::fromUri() for details.
     *
     * @return static
     *   A new Url object for an 'internal:' URI.
     *
     * @throws \InvalidArgumentException
     *   Thrown when the URI's path component doesn't have a leading slash.
     */
    protected static function fromInternalUri(array $uri_parts, array $options) {
        // Both PathValidator::getUrlIfValidWithoutAccessCheck() and 'base:' URIs
        // only accept/contain paths without a leading slash, unlike 'internal:'
        // URIs, for which the leading slash means "relative to Drupal root" and
        // "relative to Symfony app root" (just like in Symfony/Drupal 8 routes).
        if (empty($uri_parts['path'])) {
            $uri_parts['path'] = '<none>';
        }
        elseif ($uri_parts['path'] === '/') {
            $uri_parts['path'] = '<front>';
        }
        else {
            if ($uri_parts['path'][0] !== '/') {
                throw new \InvalidArgumentException("The internal path component '{$uri_parts['path']}' is invalid. Its path component must have a leading slash, e.g. internal:/foo.");
            }
            // Remove the leading slash.
            $uri_parts['path'] = substr($uri_parts['path'], 1);
            if (UrlHelper::isExternal($uri_parts['path'])) {
                throw new \InvalidArgumentException("The internal path component '{$uri_parts['path']}' is external. You are not allowed to specify an external URL together with internal:/.");
            }
        }
        $url = \Drupal::pathValidator()->getUrlIfValidWithoutAccessCheck($uri_parts['path']) ?: static::fromUri('base:' . $uri_parts['path'], $options);
        // Allow specifying additional options.
        $url->setOptions($options + $url->getOptions());
        return $url;
    }
    
    /**
     * Creates a new Url object for 'route:' URIs.
     *
     * @param array $uri_parts
     *   Parts from a URI of the form route:{route_name};{route_parameters} as
     *   from parse_url(), where the path is the route name optionally followed by
     *   a ";" followed by route parameters in key=value format with & separators.
     * @param array $options
     *   An array of options, see \Drupal\Core\Url::fromUri() for details.
     * @param string $uri
     *   The original passed in URI.
     *
     * @return static
     *   A new Url object for a 'route:' URI.
     *
     * @throws \InvalidArgumentException
     *   Thrown when the route URI does not have a route name.
     */
    protected static function fromRouteUri(array $uri_parts, array $options, $uri) {
        $route_parts = explode(';', $uri_parts['path'], 2);
        $route_name = $route_parts[0];
        if ($route_name === '') {
            throw new \InvalidArgumentException("The route URI '{$uri}' is invalid. You must have a route name in the URI. e.g., route:system.admin");
        }
        $route_parameters = [];
        if (!empty($route_parts[1])) {
            parse_str($route_parts[1], $route_parameters);
        }
        return new static($route_name, $route_parameters, $options);
    }
    
    /**
     * Returns the Url object matching a request.
     *
     * SECURITY NOTE: The request path is not checked to be valid and accessible
     * by the current user to allow storing and reusing Url objects by different
     * users. The 'path.validator' service getUrlIfValid() method should be used
     * instead of this one if validation and access check is desired. Otherwise,
     * 'access_manager' service checkNamedRoute() method should be used on the
     * router name and parameters stored in the Url object returned by this
     * method.
     *
     * @param \Symfony\Component\HttpFoundation\Request $request
     *   A request object.
     *
     * @return static
     *   A Url object. Warning: the object is created even if the current user
     *   would get an access denied running the same request via the normal page
     *   flow.
     *
     * @throws \Drupal\Core\Routing\MatchingRouteNotFoundException
     *   Thrown when the request cannot be matched.
     */
    public static function createFromRequest(Request $request) {
        // We use the router without access checks because URL objects might be
        // created and stored for different users.
        $result = \Drupal::service('router.no_access_checks')->matchRequest($request);
        $route_name = $result[RouteObjectInterface::ROUTE_NAME];
        $route_parameters = $result['_raw_variables']->all();
        return new static($route_name, $route_parameters);
    }
    
    /**
     * Sets this URL to encapsulate an unrouted URI.
     *
     * @return $this
     */
    protected function setUnrouted() {
        $this->unrouted = TRUE;
        // What was passed in as the route name is actually the URI.
        // @todo Consider fixing this in https://www.drupal.org/node/2346787.
        $this->uri = $this->routeName;
        // Set empty route name and parameters.
        $this->routeName = NULL;
        $this->routeParameters = [];
        return $this;
    }
    
    /**
     * Generates a URI string that represents the data in the Url object.
     *
     * The URI will typically have the scheme of route: even if the object was
     * constructed using an entity: or internal: scheme. An internal: URI that
     * does not match a Drupal route with be returned here with the base: scheme,
     * and external URLs will be returned in their original form.
     *
     * @return string
     *   A URI representation of the Url object data.
     */
    public function toUriString() {
        if ($this->isRouted()) {
            $uri = 'route:' . $this->routeName;
            if ($this->routeParameters) {
                $uri .= ';' . UrlHelper::buildQuery($this->routeParameters);
            }
        }
        else {
            $uri = $this->uri;
        }
        $query = !empty($this->options['query']) ? '?' . UrlHelper::buildQuery($this->options['query']) : '';
        $fragment = isset($this->options['fragment']) && strlen($this->options['fragment']) ? '#' . $this->options['fragment'] : '';
        return $uri . $query . $fragment;
    }
    
    /**
     * Indicates if this URL is external.
     *
     * @return bool
     */
    public function isExternal() {
        return $this->external;
    }
    
    /**
     * Indicates if this URL has a Drupal route.
     *
     * @return bool
     */
    public function isRouted() {
        return !$this->unrouted;
    }
    
    /**
     * Returns the route name.
     *
     * @return string
     *
     * @throws \UnexpectedValueException.
     *   If this is a URI with no corresponding route.
     */
    public function getRouteName() {
        if ($this->unrouted) {
            throw new \UnexpectedValueException($this->getUri() . ' has no corresponding route.');
        }
        return $this->routeName;
    }
    
    /**
     * Returns the route parameters.
     *
     * @return array
     *
     * @throws \UnexpectedValueException.
     *   If this is a URI with no corresponding route.
     */
    public function getRouteParameters() {
        if ($this->unrouted) {
            throw new \UnexpectedValueException('External URLs do not have internal route parameters.');
        }
        return $this->routeParameters;
    }
    
    /**
     * Sets the route parameters.
     *
     * @param array $parameters
     *   The array of parameters.
     *
     * @return $this
     *
     * @throws \UnexpectedValueException.
     *   If this is a URI with no corresponding route.
     */
    public function setRouteParameters($parameters) {
        if ($this->unrouted) {
            throw new \UnexpectedValueException('External URLs do not have route parameters.');
        }
        $this->routeParameters = $parameters;
        return $this;
    }
    
    /**
     * Sets a specific route parameter.
     *
     * @param string $key
     *   The key of the route parameter.
     * @param mixed $value
     *   The route parameter.
     *
     * @return $this
     *
     * @throws \UnexpectedValueException.
     *   If this is a URI with no corresponding route.
     */
    public function setRouteParameter($key, $value) {
        if ($this->unrouted) {
            throw new \UnexpectedValueException('External URLs do not have route parameters.');
        }
        $this->routeParameters[$key] = $value;
        return $this;
    }
    
    /**
     * Returns the URL options.
     *
     * @return array
     *   The array of options. See \Drupal\Core\Url::fromUri() for details on what
     *   it contains.
     */
    public function getOptions() {
        return $this->options;
    }
    
    /**
     * Gets a specific option.
     *
     * See \Drupal\Core\Url::fromUri() for details on the options.
     *
     * @param string $name
     *   The name of the option.
     *
     * @return mixed
     *   The value for a specific option, or NULL if it does not exist.
     */
    public function getOption($name) {
        if (!isset($this->options[$name])) {
            return NULL;
        }
        return $this->options[$name];
    }
    
    /**
     * Sets the URL options.
     *
     * @param array $options
     *   The array of options. See \Drupal\Core\Url::fromUri() for details on what
     *   it contains.
     *
     * @return $this
     */
    public function setOptions($options) {
        $this->options = $options;
        return $this;
    }
    
    /**
     * Sets a specific option.
     *
     * See \Drupal\Core\Url::fromUri() for details on the options.
     *
     * @param string $name
     *   The name of the option.
     * @param mixed $value
     *   The option value.
     *
     * @return $this
     */
    public function setOption($name, $value) {
        $this->options[$name] = $value;
        return $this;
    }
    
    /**
     * Merges the URL options with any currently set.
     *
     * In the case of conflict with existing options, the new options will replace
     * the existing options.
     *
     * @param array $options
     *   The array of options. See \Drupal\Core\Url::fromUri() for details on what
     *   it contains.
     *
     * @return $this
     */
    public function mergeOptions($options) {
        $this->options = NestedArray::mergeDeep($this->options, $options);
        return $this;
    }
    
    /**
     * Returns the URI value for this Url object.
     *
     * Only to be used if self::$unrouted is TRUE.
     *
     * @return string
     *   A URI not connected to a route. May be an external URL.
     *
     * @throws \UnexpectedValueException
     *   Thrown when the URI was requested for a routed URL.
     */
    public function getUri() {
        if (!$this->unrouted) {
            throw new \UnexpectedValueException('This URL has a Drupal route, so the canonical form is not a URI.');
        }
        return $this->uri;
    }
    
    /**
     * Sets the value of the absolute option for this Url.
     *
     * @param bool $absolute
     *   (optional) Whether to make this URL absolute or not. Defaults to TRUE.
     *
     * @return $this
     */
    public function setAbsolute($absolute = TRUE) {
        $this->options['absolute'] = $absolute;
        return $this;
    }
    
    /**
     * Generates the string URL representation for this Url object.
     *
     * For an external URL, the string will contain the input plus any query
     * string or fragment specified by the options array.
     *
     * If this Url object was constructed from a Drupal route or from an internal
     * URI (URIs using the internal:, base:, or entity: schemes), the returned
     * string will either be a relative URL like /node/1 or an absolute URL like
     * http://example.com/node/1 depending on the options array, plus any
     * specified query string or fragment.
     *
     * @param bool $collect_bubbleable_metadata
     *   (optional) Defaults to FALSE. When TRUE, both the generated URL and its
     *   associated bubbleable metadata are returned.
     *
     * @return string|\Drupal\Core\GeneratedUrl
     *   A string URL.
     *   When $collect_bubbleable_metadata is TRUE, a GeneratedUrl object is
     *   returned, containing the generated URL plus bubbleable metadata.
     */
    public function toString($collect_bubbleable_metadata = FALSE) {
        if ($this->unrouted) {
            return $this->unroutedUrlAssembler()
                ->assemble($this->getUri(), $this->getOptions(), $collect_bubbleable_metadata);
        }
        return $this->urlGenerator()
            ->generateFromRoute($this->getRouteName(), $this->getRouteParameters(), $this->getOptions(), $collect_bubbleable_metadata);
    }
    
    /**
     * Returns the route information for a render array.
     *
     * @return array
     *   An associative array suitable for a render array.
     */
    public function toRenderArray() {
        $render_array = [
            '#url' => $this,
            '#options' => $this->getOptions(),
        ];
        if (!$this->unrouted) {
            $render_array['#access_callback'] = [
                self::class,
                'renderAccess',
            ];
        }
        return $render_array;
    }
    
    /**
     * Returns the internal path (system path) for this route.
     *
     * This path will not include any prefixes, fragments, or query strings.
     *
     * @return string
     *   The internal path for this route.
     *
     * @throws \UnexpectedValueException.
     *   If this is a URI with no corresponding system path.
     */
    public function getInternalPath() {
        if ($this->unrouted) {
            throw new \UnexpectedValueException('Unrouted URIs do not have internal representations.');
        }
        if (!isset($this->internalPath)) {
            $this->internalPath = $this->urlGenerator()
                ->getPathFromRoute($this->getRouteName(), $this->getRouteParameters());
        }
        return $this->internalPath;
    }
    
    /**
     * Checks this Url object against applicable access check services.
     *
     * Determines whether the route is accessible or not.
     *
     * @param \Drupal\Core\Session\AccountInterface|null $account
     *   (optional) Run access checks for this account. NULL for the current user.
     * @param bool $return_as_object
     *   (optional) Defaults to FALSE.
     *
     * @return bool|\Drupal\Core\Access\AccessResultInterface
     *   The access result. Returns a boolean if $return_as_object is FALSE (this
     *   is the default) and otherwise an AccessResultInterface object.
     *   When a boolean is returned, the result of AccessInterface::isAllowed() is
     *   returned, i.e. TRUE means access is explicitly allowed, FALSE means
     *   access is either explicitly forbidden or "no opinion".
     */
    public function access(AccountInterface $account = NULL, $return_as_object = FALSE) {
        if ($this->isRouted()) {
            return $this->accessManager()
                ->checkNamedRoute($this->getRouteName(), $this->getRouteParameters(), $account, $return_as_object);
        }
        return $return_as_object ? AccessResult::allowed() : TRUE;
    }
    
    /**
     * Checks a URL render element against applicable access check services.
     *
     * @param array $element
     *   A render element as returned from \Drupal\Core\Url::toRenderArray().
     *
     * @return bool
     *   Returns TRUE if the current user has access to the URL, otherwise FALSE.
     */
    public static function renderAccess(array $element) {
        return $element['#url']->access();
    }
    
    /**
     * @return \Drupal\Core\Access\AccessManagerInterface
     */
    protected function accessManager() {
        if (!isset($this->accessManager)) {
            $this->accessManager = \Drupal::service('access_manager');
        }
        return $this->accessManager;
    }
    
    /**
     * Gets the URL generator.
     *
     * @return \Drupal\Core\Routing\UrlGeneratorInterface
     *   The URL generator.
     */
    protected function urlGenerator() {
        if (!$this->urlGenerator) {
            $this->urlGenerator = \Drupal::urlGenerator();
        }
        return $this->urlGenerator;
    }
    
    /**
     * Gets the unrouted URL assembler for non-Drupal URLs.
     *
     * @return \Drupal\Core\Utility\UnroutedUrlAssemblerInterface
     *   The unrouted URL assembler.
     */
    protected function unroutedUrlAssembler() {
        if (!$this->urlAssembler) {
            $this->urlAssembler = \Drupal::service('unrouted_url_assembler');
        }
        return $this->urlAssembler;
    }
    
    /**
     * Sets the URL generator.
     *
     * @param \Drupal\Core\Routing\UrlGeneratorInterface $url_generator
     *   (optional) The URL generator, specify NULL to reset it.
     *
     * @return $this
     */
    public function setUrlGenerator(UrlGeneratorInterface $url_generator = NULL) {
        $this->urlGenerator = $url_generator;
        $this->internalPath = NULL;
        return $this;
    }
    
    /**
     * Sets the unrouted URL assembler.
     *
     * @param \Drupal\Core\Utility\UnroutedUrlAssemblerInterface $url_assembler
     *   The unrouted URL assembler.
     *
     * @return $this
     */
    public function setUnroutedUrlAssembler(UnroutedUrlAssemblerInterface $url_assembler) {
        $this->urlAssembler = $url_assembler;
        return $this;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function trustedCallbacks() {
        return [
            'renderAccess',
        ];
    }

}