Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\Core\Routing;
Chris@0: 
Chris@0: use Symfony\Component\Routing\RouteCompilerInterface;
Chris@0: use Symfony\Component\Routing\Route;
Chris@0: use Symfony\Component\Routing\RouteCompiler as SymfonyRouteCompiler;
Chris@0: 
Chris@0: /**
Chris@0:  * Compiler to generate derived information from a Route necessary for matching.
Chris@0:  */
Chris@0: class RouteCompiler extends SymfonyRouteCompiler implements RouteCompilerInterface {
Chris@0: 
Chris@0:   /**
Chris@0:    * Utility constant to use for regular expressions against the path.
Chris@0:    */
Chris@0:   const REGEX_DELIMITER = '#';
Chris@0: 
Chris@0:   /**
Chris@0:    * Compiles the current route instance.
Chris@0:    *
Chris@0:    * Because so much of the parent class is private, we need to call the parent
Chris@0:    * class's compile() method and then dissect its return value to build our
Chris@0:    * new compiled object.  If upstream gets refactored so we can subclass more
Chris@0:    * easily then this may not be necessary.
Chris@0:    *
Chris@0:    * @param \Symfony\Component\Routing\Route $route
Chris@0:    *   A Route instance.
Chris@0:    *
Chris@0:    * @return \Drupal\Core\Routing\CompiledRoute
Chris@0:    *   A CompiledRoute instance.
Chris@0:    */
Chris@0:   public static function compile(Route $route) {
Chris@18:     // Symfony 4 requires that all UTF-8 route patterns have the "utf8" option
Chris@18:     // set and Drupal does not support non UTF-8 routes.
Chris@18:     $route->setOption('utf8', TRUE);
Chris@0:     $symfony_compiled = parent::compile($route);
Chris@0: 
Chris@0:     // The Drupal-specific compiled information.
Chris@0:     $stripped_path = static::getPathWithoutDefaults($route);
Chris@0:     $fit = static::getFit($stripped_path);
Chris@0:     $pattern_outline = static::getPatternOutline($stripped_path);
Chris@0:     // We count the number of parts including any optional trailing parts. This
Chris@0:     // allows the RouteProvider to filter candidate routes more efficiently.
Chris@0:     $num_parts = count(explode('/', trim($route->getPath(), '/')));
Chris@0: 
Chris@0:     return new CompiledRoute(
Chris@0:       $fit,
Chris@0:       $pattern_outline,
Chris@0:       $num_parts,
Chris@0: 
Chris@0:       // The following parameters are what Symfony uses in
Chris@0:       // \Symfony\Component\Routing\Matcher\UrlMatcher::matchCollection().
Chris@0: 
Chris@0:       // Set the static prefix to an empty string since it is redundant to
Chris@0:       // the matching in \Drupal\Core\Routing\RouteProvider::getRoutesByPath()
Chris@0:       // and by skipping it we more easily make the routing case-insensitive.
Chris@0:       '',
Chris@0:       $symfony_compiled->getRegex(),
Chris@0:       $symfony_compiled->getTokens(),
Chris@0:       $symfony_compiled->getPathVariables(),
Chris@0:       $symfony_compiled->getHostRegex(),
Chris@0:       $symfony_compiled->getHostTokens(),
Chris@0:       $symfony_compiled->getHostVariables(),
Chris@0:       $symfony_compiled->getVariables()
Chris@0:     );
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Returns the pattern outline.
Chris@0:    *
Chris@0:    * The pattern outline is the path pattern but normalized so that all
Chris@0:    * placeholders are the string '%'.
Chris@0:    *
Chris@0:    * @param string $path
Chris@0:    *   The path for which we want the normalized outline.
Chris@0:    *
Chris@0:    * @return string
Chris@0:    *   The path pattern outline.
Chris@0:    */
Chris@0:   public static function getPatternOutline($path) {
Chris@0:     return preg_replace('#\{\w+\}#', '%', $path);
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Determines the fitness of the provided path.
Chris@0:    *
Chris@0:    * @param string $path
Chris@0:    *   The path whose fitness we want.
Chris@0:    *
Chris@0:    * @return int
Chris@0:    *   The fitness of the path, as an integer.
Chris@0:    */
Chris@0:   public static function getFit($path) {
Chris@0:     $parts = explode('/', trim($path, '/'));
Chris@0:     $number_parts = count($parts);
Chris@0:     // We store the highest index of parts here to save some work in the fit
Chris@0:     // calculation loop.
Chris@0:     $slashes = $number_parts - 1;
Chris@0:     // The fit value is a binary number which has 1 at every fixed path
Chris@0:     // position and 0 where there is a wildcard. We keep track of all such
Chris@0:     // patterns that exist so that we can minimize the number of path
Chris@0:     // patterns we need to check in the RouteProvider.
Chris@0:     $fit = 0;
Chris@0:     foreach ($parts as $k => $part) {
Chris@0:       if (strpos($part, '{') === FALSE) {
Chris@0:         $fit |= 1 << ($slashes - $k);
Chris@0:       }
Chris@0:     }
Chris@0: 
Chris@0:     return $fit;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Returns the path of the route, without placeholders with a default value.
Chris@0:    *
Chris@0:    * When computing the path outline and fit, we want to skip default-value
Chris@0:    * placeholders.  If we didn't, the path would never match.  Note that this
Chris@0:    * only works for placeholders at the end of the path. Infix placeholders
Chris@0:    * with default values don't make sense anyway, so that should not be a
Chris@0:    * problem.
Chris@0:    *
Chris@0:    * @param \Symfony\Component\Routing\Route $route
Chris@0:    *   The route to have the placeholders removed from.
Chris@0:    *
Chris@0:    * @return string
Chris@0:    *   The path string, stripped of placeholders that have default values.
Chris@0:    */
Chris@0:   public static function getPathWithoutDefaults(Route $route) {
Chris@0:     $path = $route->getPath();
Chris@0:     $defaults = $route->getDefaults();
Chris@0: 
Chris@0:     // Remove placeholders with default values from the outline, so that they
Chris@0:     // will still match.
Chris@0:     $remove = array_map(function ($a) {
Chris@0:       return '/{' . $a . '}';
Chris@0:     }, array_keys($defaults));
Chris@0:     $path = str_replace($remove, '', $path);
Chris@0: 
Chris@0:     return $path;
Chris@0:   }
Chris@0: 
Chris@0: }