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