Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\Component\FileCache;
Chris@0: 
Chris@0: /**
Chris@0:  * Allows to cache data based on file modification dates.
Chris@0:  */
Chris@0: class FileCache implements FileCacheInterface {
Chris@0: 
Chris@0:   /**
Chris@0:    * Prefix that is used for cache entries.
Chris@0:    *
Chris@0:    * @var string
Chris@0:    */
Chris@0:   protected $prefix;
Chris@0: 
Chris@0:   /**
Chris@0:    * Static cache that contains already loaded cache entries.
Chris@0:    *
Chris@0:    * @var array
Chris@0:    */
Chris@0:   protected static $cached = [];
Chris@0: 
Chris@0:   /**
Chris@0:    * The collection identifier of this cache.
Chris@0:    *
Chris@0:    * @var string
Chris@0:    */
Chris@0:   protected $collection;
Chris@0: 
Chris@0:   /**
Chris@0:    * The cache backend backing this FileCache object.
Chris@0:    *
Chris@0:    * @var \Drupal\Component\FileCache\FileCacheBackendInterface
Chris@0:    */
Chris@0:   protected $cache;
Chris@0: 
Chris@0:   /**
Chris@0:    * Constructs a FileCache object.
Chris@0:    *
Chris@0:    * @param string $prefix
Chris@0:    *   The cache prefix.
Chris@0:    * @param string $collection
Chris@0:    *   A collection identifier to ensure that the same files could be cached for
Chris@0:    *   different purposes without clashing.
Chris@0:    * @param string|null $cache_backend_class
Chris@0:    *   (optional) The class that should be used as cache backend.
Chris@0:    * @param array $cache_backend_configuration
Chris@0:    *   (optional) The configuration for the backend class.
Chris@0:    */
Chris@0:   public function __construct($prefix, $collection, $cache_backend_class = NULL, array $cache_backend_configuration = []) {
Chris@0: 
Chris@0:     if (empty($prefix)) {
Chris@0:       throw new \InvalidArgumentException('Required prefix configuration is missing');
Chris@0:     }
Chris@0: 
Chris@0:     $this->prefix = $prefix;
Chris@0:     $this->collection = $collection;
Chris@0: 
Chris@0:     if (isset($cache_backend_class)) {
Chris@0:       $this->cache = new $cache_backend_class($cache_backend_configuration);
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function get($filepath) {
Chris@0:     $filepaths = [$filepath];
Chris@0:     $cached = $this->getMultiple($filepaths);
Chris@0:     return isset($cached[$filepath]) ? $cached[$filepath] : NULL;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function getMultiple(array $filepaths) {
Chris@0:     $file_data = [];
Chris@0:     $remaining_cids = [];
Chris@0: 
Chris@0:     // First load from the static cache what we can.
Chris@0:     foreach ($filepaths as $filepath) {
Chris@0:       if (!file_exists($filepath)) {
Chris@0:         continue;
Chris@0:       }
Chris@0: 
Chris@0:       $realpath = realpath($filepath);
Chris@0:       // If the file exists but realpath returns nothing, it is using a stream
Chris@0:       // wrapper, those are not supported.
Chris@0:       if (empty($realpath)) {
Chris@0:         continue;
Chris@0:       }
Chris@0: 
Chris@0:       $cid = $this->prefix . ':' . $this->collection . ':' . $realpath;
Chris@0:       if (isset(static::$cached[$cid]) && static::$cached[$cid]['mtime'] == filemtime($filepath)) {
Chris@0:         $file_data[$filepath] = static::$cached[$cid]['data'];
Chris@0:       }
Chris@0:       else {
Chris@0:         // Collect a list of cache IDs that we still need to fetch from cache
Chris@0:         // backend.
Chris@0:         $remaining_cids[$cid] = $filepath;
Chris@0:       }
Chris@0:     }
Chris@0: 
Chris@0:     // If there are any cache IDs left to fetch from the cache backend.
Chris@0:     if ($remaining_cids && $this->cache) {
Chris@0:       $cache_results = $this->cache->fetch(array_keys($remaining_cids)) ?: [];
Chris@0:       foreach ($cache_results as $cid => $cached) {
Chris@0:         $filepath = $remaining_cids[$cid];
Chris@0:         if ($cached['mtime'] == filemtime($filepath)) {
Chris@0:           $file_data[$cached['filepath']] = $cached['data'];
Chris@0:           static::$cached[$cid] = $cached;
Chris@0:         }
Chris@0:       }
Chris@0:     }
Chris@0: 
Chris@0:     return $file_data;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function set($filepath, $data) {
Chris@0:     $realpath = realpath($filepath);
Chris@0:     $cached = [
Chris@0:       'mtime' => filemtime($filepath),
Chris@0:       'filepath' => $filepath,
Chris@0:       'data' => $data,
Chris@0:     ];
Chris@0: 
Chris@0:     $cid = $this->prefix . ':' . $this->collection . ':' . $realpath;
Chris@0:     static::$cached[$cid] = $cached;
Chris@0:     if ($this->cache) {
Chris@0:       $this->cache->store($cid, $cached);
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function delete($filepath) {
Chris@0:     $realpath = realpath($filepath);
Chris@0:     $cid = $this->prefix . ':' . $this->collection . ':' . $realpath;
Chris@0: 
Chris@0:     unset(static::$cached[$cid]);
Chris@0:     if ($this->cache) {
Chris@0:       $this->cache->delete($cid);
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Resets the static cache.
Chris@0:    *
Chris@0:    * @todo Replace this once https://www.drupal.org/node/2260187 is in.
Chris@0:    */
Chris@0:   public static function reset() {
Chris@0:     static::$cached = [];
Chris@0:   }
Chris@0: 
Chris@0: }