Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\Core\Path;
Chris@0: 
Chris@0: use Drupal\Core\Cache\CacheBackendInterface;
Chris@0: use Drupal\Core\CacheDecorator\CacheDecoratorInterface;
Chris@0: use Drupal\Core\Language\LanguageInterface;
Chris@0: use Drupal\Core\Language\LanguageManagerInterface;
Chris@0: 
Chris@0: /**
Chris@0:  * The default alias manager implementation.
Chris@0:  */
Chris@0: class AliasManager implements AliasManagerInterface, CacheDecoratorInterface {
Chris@0: 
Chris@0:   /**
Chris@0:    * The alias storage service.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Path\AliasStorageInterface
Chris@0:    */
Chris@0:   protected $storage;
Chris@0: 
Chris@0:   /**
Chris@0:    * Cache backend service.
Chris@0:    *
Chris@17:    * @var \Drupal\Core\Cache\CacheBackendInterface
Chris@0:    */
Chris@0:   protected $cache;
Chris@0: 
Chris@0:   /**
Chris@0:    * The cache key to use when caching paths.
Chris@0:    *
Chris@0:    * @var string
Chris@0:    */
Chris@0:   protected $cacheKey;
Chris@0: 
Chris@0:   /**
Chris@0:    * Whether the cache needs to be written.
Chris@0:    *
Chris@0:    * @var bool
Chris@0:    */
Chris@0:   protected $cacheNeedsWriting = FALSE;
Chris@0: 
Chris@0:   /**
Chris@0:    * Language manager for retrieving the default langcode when none is specified.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Language\LanguageManagerInterface
Chris@0:    */
Chris@0:   protected $languageManager;
Chris@0: 
Chris@0:   /**
Chris@0:    * Holds the map of path lookups per language.
Chris@0:    *
Chris@0:    * @var array
Chris@0:    */
Chris@0:   protected $lookupMap = [];
Chris@0: 
Chris@0:   /**
Chris@0:    * Holds an array of aliases for which no path was found.
Chris@0:    *
Chris@0:    * @var array
Chris@0:    */
Chris@0:   protected $noPath = [];
Chris@0: 
Chris@0:   /**
Chris@0:    * Holds the array of whitelisted path aliases.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Path\AliasWhitelistInterface
Chris@0:    */
Chris@0:   protected $whitelist;
Chris@0: 
Chris@0:   /**
Chris@0:    * Holds an array of paths that have no alias.
Chris@0:    *
Chris@0:    * @var array
Chris@0:    */
Chris@0:   protected $noAlias = [];
Chris@0: 
Chris@0:   /**
Chris@0:    * Whether preloaded path lookups has already been loaded.
Chris@0:    *
Chris@0:    * @var array
Chris@0:    */
Chris@0:   protected $langcodePreloaded = [];
Chris@0: 
Chris@0:   /**
Chris@0:    * Holds an array of previously looked up paths for the current request path.
Chris@0:    *
Chris@0:    * This will only get populated if a cache key has been set, which for example
Chris@0:    * happens if the alias manager is used in the context of a request.
Chris@0:    *
Chris@0:    * @var array
Chris@0:    */
Chris@0:   protected $preloadedPathLookups = FALSE;
Chris@0: 
Chris@0:   /**
Chris@0:    * Constructs an AliasManager.
Chris@0:    *
Chris@0:    * @param \Drupal\Core\Path\AliasStorageInterface $storage
Chris@0:    *   The alias storage service.
Chris@0:    * @param \Drupal\Core\Path\AliasWhitelistInterface $whitelist
Chris@0:    *   The whitelist implementation to use.
Chris@0:    * @param \Drupal\Core\Language\LanguageManagerInterface $language_manager
Chris@0:    *   The language manager.
Chris@0:    * @param \Drupal\Core\Cache\CacheBackendInterface $cache
Chris@0:    *   Cache backend.
Chris@0:    */
Chris@0:   public function __construct(AliasStorageInterface $storage, AliasWhitelistInterface $whitelist, LanguageManagerInterface $language_manager, CacheBackendInterface $cache) {
Chris@0:     $this->storage = $storage;
Chris@0:     $this->languageManager = $language_manager;
Chris@0:     $this->whitelist = $whitelist;
Chris@0:     $this->cache = $cache;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function setCacheKey($key) {
Chris@0:     // Prefix the cache key to avoid clashes with other caches.
Chris@0:     $this->cacheKey = 'preload-paths:' . $key;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    *
Chris@0:    * Cache an array of the paths available on each page. We assume that aliases
Chris@0:    * will be needed for the majority of these paths during subsequent requests,
Chris@0:    * and load them in a single query during path alias lookup.
Chris@0:    */
Chris@0:   public function writeCache() {
Chris@0:     // Check if the paths for this page were loaded from cache in this request
Chris@0:     // to avoid writing to cache on every request.
Chris@0:     if ($this->cacheNeedsWriting && !empty($this->cacheKey)) {
Chris@0:       // Start with the preloaded path lookups, so that cached entries for other
Chris@0:       // languages will not be lost.
Chris@0:       $path_lookups = $this->preloadedPathLookups ?: [];
Chris@0:       foreach ($this->lookupMap as $langcode => $lookups) {
Chris@0:         $path_lookups[$langcode] = array_keys($lookups);
Chris@0:         if (!empty($this->noAlias[$langcode])) {
Chris@0:           $path_lookups[$langcode] = array_merge($path_lookups[$langcode], array_keys($this->noAlias[$langcode]));
Chris@0:         }
Chris@0:       }
Chris@0: 
Chris@0:       $twenty_four_hours = 60 * 60 * 24;
Chris@0:       $this->cache->set($this->cacheKey, $path_lookups, $this->getRequestTime() + $twenty_four_hours);
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function getPathByAlias($alias, $langcode = NULL) {
Chris@0:     // If no language is explicitly specified we default to the current URL
Chris@0:     // language. If we used a language different from the one conveyed by the
Chris@0:     // requested URL, we might end up being unable to check if there is a path
Chris@0:     // alias matching the URL path.
Chris@0:     $langcode = $langcode ?: $this->languageManager->getCurrentLanguage(LanguageInterface::TYPE_URL)->getId();
Chris@0: 
Chris@0:     // If we already know that there are no paths for this alias simply return.
Chris@0:     if (empty($alias) || !empty($this->noPath[$langcode][$alias])) {
Chris@0:       return $alias;
Chris@0:     }
Chris@0: 
Chris@0:     // Look for the alias within the cached map.
Chris@0:     if (isset($this->lookupMap[$langcode]) && ($path = array_search($alias, $this->lookupMap[$langcode]))) {
Chris@0:       return $path;
Chris@0:     }
Chris@0: 
Chris@0:     // Look for path in storage.
Chris@0:     if ($path = $this->storage->lookupPathSource($alias, $langcode)) {
Chris@0:       $this->lookupMap[$langcode][$path] = $alias;
Chris@0:       return $path;
Chris@0:     }
Chris@0: 
Chris@0:     // We can't record anything into $this->lookupMap because we didn't find any
Chris@0:     // paths for this alias. Thus cache to $this->noPath.
Chris@0:     $this->noPath[$langcode][$alias] = TRUE;
Chris@0: 
Chris@0:     return $alias;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function getAliasByPath($path, $langcode = NULL) {
Chris@0:     if ($path[0] !== '/') {
Chris@0:       throw new \InvalidArgumentException(sprintf('Source path %s has to start with a slash.', $path));
Chris@0:     }
Chris@0:     // If no language is explicitly specified we default to the current URL
Chris@0:     // language. If we used a language different from the one conveyed by the
Chris@0:     // requested URL, we might end up being unable to check if there is a path
Chris@0:     // alias matching the URL path.
Chris@0:     $langcode = $langcode ?: $this->languageManager->getCurrentLanguage(LanguageInterface::TYPE_URL)->getId();
Chris@0: 
Chris@0:     // Check the path whitelist, if the top-level part before the first /
Chris@0:     // is not in the list, then there is no need to do anything further,
Chris@0:     // it is not in the database.
Chris@0:     if ($path === '/' || !$this->whitelist->get(strtok(trim($path, '/'), '/'))) {
Chris@0:       return $path;
Chris@0:     }
Chris@0: 
Chris@0:     // During the first call to this method per language, load the expected
Chris@0:     // paths for the page from cache.
Chris@0:     if (empty($this->langcodePreloaded[$langcode])) {
Chris@0:       $this->langcodePreloaded[$langcode] = TRUE;
Chris@0:       $this->lookupMap[$langcode] = [];
Chris@0: 
Chris@0:       // Load the cached paths that should be used for preloading. This only
Chris@0:       // happens if a cache key has been set.
Chris@0:       if ($this->preloadedPathLookups === FALSE) {
Chris@0:         $this->preloadedPathLookups = [];
Chris@0:         if ($this->cacheKey) {
Chris@0:           if ($cached = $this->cache->get($this->cacheKey)) {
Chris@0:             $this->preloadedPathLookups = $cached->data;
Chris@0:           }
Chris@0:           else {
Chris@0:             $this->cacheNeedsWriting = TRUE;
Chris@0:           }
Chris@0:         }
Chris@0:       }
Chris@0: 
Chris@0:       // Load paths from cache.
Chris@0:       if (!empty($this->preloadedPathLookups[$langcode])) {
Chris@0:         $this->lookupMap[$langcode] = $this->storage->preloadPathAlias($this->preloadedPathLookups[$langcode], $langcode);
Chris@0:         // Keep a record of paths with no alias to avoid querying twice.
Chris@0:         $this->noAlias[$langcode] = array_flip(array_diff_key($this->preloadedPathLookups[$langcode], array_keys($this->lookupMap[$langcode])));
Chris@0:       }
Chris@0:     }
Chris@0: 
Chris@0:     // If we already know that there are no aliases for this path simply return.
Chris@0:     if (!empty($this->noAlias[$langcode][$path])) {
Chris@0:       return $path;
Chris@0:     }
Chris@0: 
Chris@0:     // If the alias has already been loaded, return it from static cache.
Chris@0:     if (isset($this->lookupMap[$langcode][$path])) {
Chris@0:       return $this->lookupMap[$langcode][$path];
Chris@0:     }
Chris@0: 
Chris@0:     // Try to load alias from storage.
Chris@0:     if ($alias = $this->storage->lookupPathAlias($path, $langcode)) {
Chris@0:       $this->lookupMap[$langcode][$path] = $alias;
Chris@0:       return $alias;
Chris@0:     }
Chris@0: 
Chris@0:     // We can't record anything into $this->lookupMap because we didn't find any
Chris@0:     // aliases for this path. Thus cache to $this->noAlias.
Chris@0:     $this->noAlias[$langcode][$path] = TRUE;
Chris@0:     return $path;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function cacheClear($source = NULL) {
Chris@0:     if ($source) {
Chris@0:       foreach (array_keys($this->lookupMap) as $lang) {
Chris@0:         unset($this->lookupMap[$lang][$source]);
Chris@0:       }
Chris@0:     }
Chris@0:     else {
Chris@0:       $this->lookupMap = [];
Chris@0:     }
Chris@0:     $this->noPath = [];
Chris@0:     $this->noAlias = [];
Chris@0:     $this->langcodePreloaded = [];
Chris@0:     $this->preloadedPathLookups = [];
Chris@0:     $this->cache->delete($this->cacheKey);
Chris@0:     $this->pathAliasWhitelistRebuild($source);
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Rebuild the path alias white list.
Chris@0:    *
Chris@0:    * @param string $path
Chris@0:    *   An optional path for which an alias is being inserted.
Chris@0:    *
Chris@0:    * @return
Chris@0:    *   An array containing a white list of path aliases.
Chris@0:    */
Chris@0:   protected function pathAliasWhitelistRebuild($path = NULL) {
Chris@0:     // When paths are inserted, only rebuild the whitelist if the path has a top
Chris@0:     // level component which is not already in the whitelist.
Chris@0:     if (!empty($path)) {
Chris@0:       if ($this->whitelist->get(strtok($path, '/'))) {
Chris@0:         return;
Chris@0:       }
Chris@0:     }
Chris@0:     $this->whitelist->clear();
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Wrapper method for REQUEST_TIME constant.
Chris@0:    *
Chris@0:    * @return int
Chris@0:    */
Chris@0:   protected function getRequestTime() {
Chris@0:     return defined('REQUEST_TIME') ? REQUEST_TIME : (int) $_SERVER['REQUEST_TIME'];
Chris@0:   }
Chris@0: 
Chris@0: }