Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\Core\Cache;
Chris@0: 
Chris@14: use Drupal\Component\Assertion\Inspector;
Chris@14: 
Chris@0: /**
Chris@0:  * Stores cache items in the Alternative PHP Cache User Cache (APCu).
Chris@0:  */
Chris@0: class ApcuBackend implements CacheBackendInterface {
Chris@0: 
Chris@0:   /**
Chris@0:    * The name of the cache bin to use.
Chris@0:    *
Chris@0:    * @var string
Chris@0:    */
Chris@0:   protected $bin;
Chris@0: 
Chris@0:   /**
Chris@0:    * Prefix for all keys in the storage that belong to this site.
Chris@0:    *
Chris@0:    * @var string
Chris@0:    */
Chris@0:   protected $sitePrefix;
Chris@0: 
Chris@0:   /**
Chris@0:    * Prefix for all keys in this cache bin.
Chris@0:    *
Chris@0:    * Includes the site-specific prefix in $sitePrefix.
Chris@0:    *
Chris@0:    * @var string
Chris@0:    */
Chris@0:   protected $binPrefix;
Chris@0: 
Chris@0:   /**
Chris@0:    * The cache tags checksum provider.
Chris@0:    *
Chris@0:    * @var \Drupal\Core\Cache\CacheTagsChecksumInterface
Chris@0:    */
Chris@0:   protected $checksumProvider;
Chris@0: 
Chris@0:   /**
Chris@0:    * Constructs a new ApcuBackend instance.
Chris@0:    *
Chris@0:    * @param string $bin
Chris@0:    *   The name of the cache bin.
Chris@0:    * @param string $site_prefix
Chris@0:    *   The prefix to use for all keys in the storage that belong to this site.
Chris@0:    * @param \Drupal\Core\Cache\CacheTagsChecksumInterface $checksum_provider
Chris@0:    *   The cache tags checksum provider.
Chris@0:    */
Chris@0:   public function __construct($bin, $site_prefix, CacheTagsChecksumInterface $checksum_provider) {
Chris@0:     $this->bin = $bin;
Chris@0:     $this->sitePrefix = $site_prefix;
Chris@0:     $this->checksumProvider = $checksum_provider;
Chris@0:     $this->binPrefix = $this->sitePrefix . '::' . $this->bin . '::';
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Prepends the APCu user variable prefix for this bin to a cache item ID.
Chris@0:    *
Chris@0:    * @param string $cid
Chris@0:    *   The cache item ID to prefix.
Chris@0:    *
Chris@0:    * @return string
Chris@0:    *   The APCu key for the cache item ID.
Chris@0:    */
Chris@0:   public function getApcuKey($cid) {
Chris@0:     return $this->binPrefix . $cid;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function get($cid, $allow_invalid = FALSE) {
Chris@0:     $cache = apcu_fetch($this->getApcuKey($cid));
Chris@0:     return $this->prepareItem($cache, $allow_invalid);
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function getMultiple(&$cids, $allow_invalid = FALSE) {
Chris@0:     // Translate the requested cache item IDs to APCu keys.
Chris@0:     $map = [];
Chris@0:     foreach ($cids as $cid) {
Chris@0:       $map[$this->getApcuKey($cid)] = $cid;
Chris@0:     }
Chris@0: 
Chris@0:     $result = apcu_fetch(array_keys($map));
Chris@0:     $cache = [];
Chris@0:     if ($result) {
Chris@0:       foreach ($result as $key => $item) {
Chris@0:         $item = $this->prepareItem($item, $allow_invalid);
Chris@0:         if ($item) {
Chris@0:           $cache[$map[$key]] = $item;
Chris@0:         }
Chris@0:       }
Chris@0:     }
Chris@0:     unset($result);
Chris@0: 
Chris@0:     $cids = array_diff($cids, array_keys($cache));
Chris@0:     return $cache;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Returns all cached items, optionally limited by a cache ID prefix.
Chris@0:    *
Chris@0:    * APCu is a memory cache, shared across all server processes. To prevent
Chris@0:    * cache item clashes with other applications/installations, every cache item
Chris@0:    * is prefixed with a unique string for this site. Therefore, functions like
Chris@0:    * apcu_clear_cache() cannot be used, and instead, a list of all cache items
Chris@0:    * belonging to this application need to be retrieved through this method
Chris@0:    * instead.
Chris@0:    *
Chris@0:    * @param string $prefix
Chris@0:    *   (optional) A cache ID prefix to limit the result to.
Chris@0:    *
Chris@0:    * @return \APCUIterator
Chris@0:    *   An APCUIterator containing matched items.
Chris@0:    */
Chris@0:   protected function getAll($prefix = '') {
Chris@0:     return $this->getIterator('/^' . preg_quote($this->getApcuKey($prefix), '/') . '/');
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Prepares a cached item.
Chris@0:    *
Chris@0:    * Checks that the item is either permanent or did not expire.
Chris@0:    *
Chris@0:    * @param \stdClass $cache
Chris@18:    *   An item loaded from self::get() or self::getMultiple().
Chris@0:    * @param bool $allow_invalid
Chris@0:    *   If TRUE, a cache item may be returned even if it is expired or has been
Chris@0:    *   invalidated. See ::get().
Chris@0:    *
Chris@0:    * @return mixed
Chris@0:    *   The cache item or FALSE if the item expired.
Chris@0:    */
Chris@0:   protected function prepareItem($cache, $allow_invalid) {
Chris@0:     if (!isset($cache->data)) {
Chris@0:       return FALSE;
Chris@0:     }
Chris@0: 
Chris@0:     $cache->tags = $cache->tags ? explode(' ', $cache->tags) : [];
Chris@0: 
Chris@0:     // Check expire time.
Chris@0:     $cache->valid = $cache->expire == Cache::PERMANENT || $cache->expire >= REQUEST_TIME;
Chris@0: 
Chris@0:     // Check if invalidateTags() has been called with any of the entry's tags.
Chris@0:     if (!$this->checksumProvider->isValid($cache->checksum, $cache->tags)) {
Chris@0:       $cache->valid = FALSE;
Chris@0:     }
Chris@0: 
Chris@0:     if (!$allow_invalid && !$cache->valid) {
Chris@0:       return FALSE;
Chris@0:     }
Chris@0: 
Chris@0:     return $cache;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function set($cid, $data, $expire = CacheBackendInterface::CACHE_PERMANENT, array $tags = []) {
Chris@14:     assert(Inspector::assertAllStrings($tags), 'Cache tags must be strings.');
Chris@0:     $tags = array_unique($tags);
Chris@0:     $cache = new \stdClass();
Chris@0:     $cache->cid = $cid;
Chris@0:     $cache->created = round(microtime(TRUE), 3);
Chris@0:     $cache->expire = $expire;
Chris@0:     $cache->tags = implode(' ', $tags);
Chris@0:     $cache->checksum = $this->checksumProvider->getCurrentChecksum($tags);
Chris@0:     // APCu serializes/unserializes any structure itself.
Chris@0:     $cache->serialized = 0;
Chris@0:     $cache->data = $data;
Chris@0: 
Chris@0:     // Expiration is handled by our own prepareItem(), not APCu.
Chris@0:     apcu_store($this->getApcuKey($cid), $cache);
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function setMultiple(array $items = []) {
Chris@0:     foreach ($items as $cid => $item) {
Chris@0:       $this->set($cid, $item['data'], isset($item['expire']) ? $item['expire'] : CacheBackendInterface::CACHE_PERMANENT, isset($item['tags']) ? $item['tags'] : []);
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function delete($cid) {
Chris@0:     apcu_delete($this->getApcuKey($cid));
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function deleteMultiple(array $cids) {
Chris@0:     apcu_delete(array_map([$this, 'getApcuKey'], $cids));
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function deleteAll() {
Chris@0:     apcu_delete($this->getIterator('/^' . preg_quote($this->binPrefix, '/') . '/'));
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function garbageCollection() {
Chris@0:     // APCu performs garbage collection automatically.
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function removeBin() {
Chris@0:     apcu_delete($this->getIterator('/^' . preg_quote($this->binPrefix, '/') . '/'));
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function invalidate($cid) {
Chris@0:     $this->invalidateMultiple([$cid]);
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function invalidateMultiple(array $cids) {
Chris@0:     foreach ($this->getMultiple($cids) as $cache) {
Chris@0:       $this->set($cache->cid, $cache, REQUEST_TIME - 1);
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function invalidateAll() {
Chris@0:     foreach ($this->getAll() as $data) {
Chris@0:       $cid = str_replace($this->binPrefix, '', $data['key']);
Chris@0:       $this->set($cid, $data['value'], REQUEST_TIME - 1);
Chris@0:     }
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Instantiates and returns the APCUIterator class.
Chris@0:    *
Chris@0:    * @param mixed $search
Chris@0:    *   A PCRE regular expression that matches against APC key names, either as a
Chris@0:    *   string for a single regular expression, or as an array of regular
Chris@0:    *   expressions. Or, optionally pass in NULL to skip the search.
Chris@0:    * @param int $format
Chris@0:    *   The desired format, as configured with one or more of the APC_ITER_*
Chris@0:    *   constants.
Chris@0:    * @param int $chunk_size
Chris@0:    *   The chunk size. Must be a value greater than 0. The default value is 100.
Chris@0:    * @param int $list
Chris@0:    *   The type to list. Either pass in APC_LIST_ACTIVE or APC_LIST_DELETED.
Chris@0:    *
Chris@0:    * @return \APCUIterator
Chris@0:    */
Chris@0:   protected function getIterator($search = NULL, $format = APC_ITER_ALL, $chunk_size = 100, $list = APC_LIST_ACTIVE) {
Chris@0:     return new \APCUIterator($search, $format, $chunk_size, $list);
Chris@0:   }
Chris@0: 
Chris@0: }