/Classes/TYPO3/FLOW3/Cache/Backend/ApcBackend.php
PHP | 271 lines | 105 code | 22 blank | 144 comment | 13 complexity | 9bd4497b3da26ca3c4719291baeb8d6d MD5 | raw file
Possible License(s): BSD-3-Clause, LGPL-3.0
- <?php
- namespace TYPO3\FLOW3\Cache\Backend;
- /* *
- * This script belongs to the FLOW3 framework. *
- * *
- * It is free software; you can redistribute it and/or modify it under *
- * the terms of the GNU Lesser General Public License, either version 3 *
- * of the License, or (at your option) any later version. *
- * *
- * The TYPO3 project - inspiring people to share! *
- * */
- /**
- * A caching backend which stores cache entries by using APC.
- *
- * This backend uses the following types of keys:
- * - tag_xxx
- * xxx is tag name, value is array of associated identifiers identifier. This
- * is "forward" tag index. It is mainly used for obtaining content by tag
- * (get identifier by tag -> get content by identifier)
- * - ident_xxx
- * xxx is identifier, value is array of associated tags. This is "reverse" tag
- * index. It provides quick access for all tags associated with this identifier
- * and used when removing the identifier
- * - tagIndex
- * Value is a List of all tags (array)
- *
- * Each key is prepended with a prefix. By default prefix consists from two parts
- * separated by underscore character and ends in yet another underscore character:
- * - "FLOW3"
- * - MD5 of SAPI type, path to FLOW3 and user running FLOW3
- * This prefix makes sure that keys from the different installations do not
- * conflict.
- *
- * @api
- */
- class ApcBackend extends AbstractBackend implements TaggableBackendInterface {
- /**
- * A prefix to seperate stored data from other data possible stored in the APC
- * @var string
- */
- protected $identifierPrefix;
- /**
- * Constructs this backend
- *
- * @param \TYPO3\FLOW3\Core\ApplicationContext $context FLOW3's application context
- * @param array $options Configuration options - unused here
- * @throws \TYPO3\FLOW3\Cache\Exception
- */
- public function __construct(\TYPO3\FLOW3\Core\ApplicationContext $context, array $options = array()) {
- if (!extension_loaded('apc')) {
- throw new \TYPO3\FLOW3\Cache\Exception('The PHP extension "apc" must be installed and loaded in order to use the APC backend.', 1232985414);
- }
- parent::__construct($context, $options);
- }
- /**
- * Initializes the identifier prefix when setting the cache.
- *
- * @param \TYPO3\FLOW3\Cache\Frontend\FrontendInterface $cache
- * @return void
- */
- public function setCache(\TYPO3\FLOW3\Cache\Frontend\FrontendInterface $cache) {
- parent::setCache($cache);
- $processUser = extension_loaded('posix') ? posix_getpwuid(posix_geteuid()) : array('name' => 'default');
- $pathHash = substr(md5(FLOW3_PATH_WEB . PHP_SAPI . $processUser['name'] . $this->context), 0, 12);
- $this->identifierPrefix = 'FLOW3_' . $pathHash;
- }
- /**
- * Saves data in the cache.
- *
- * @param string $entryIdentifier An identifier for this specific cache entry
- * @param string $data The data to be stored
- * @param array $tags Tags to associate with this cache entry
- * @param integer $lifetime Lifetime of this cache entry in seconds. If NULL is specified, the default lifetime is used. "0" means unlimited liftime.
- * @return void
- * @throws \TYPO3\FLOW3\Cache\Exception if no cache frontend has been set.
- * @throws \InvalidArgumentException if the identifier is not valid
- * @throws \TYPO3\FLOW3\Cache\Exception\InvalidDataException if $data is not a string
- * @api
- */
- public function set($entryIdentifier, $data, array $tags = array(), $lifetime = NULL) {
- if (!$this->cache instanceof \TYPO3\FLOW3\Cache\Frontend\FrontendInterface) {
- throw new \TYPO3\FLOW3\Cache\Exception('No cache frontend has been set yet via setCache().', 1232986818);
- }
- if (!is_string($data)) {
- throw new \TYPO3\FLOW3\Cache\Exception\InvalidDataException('The specified data is of type "' . gettype($data) . '" but a string is expected.', 1232986825);
- }
- $tags[] = '%APCBE%' . $this->cacheIdentifier;
- $expiration = $lifetime !== NULL ? $lifetime : $this->defaultLifetime;
- $success = apc_store($this->identifierPrefix . $entryIdentifier, $data, $expiration);
- if ($success === TRUE) {
- $this->removeIdentifierFromAllTags($entryIdentifier);
- $this->addIdentifierToTags($entryIdentifier, $tags);
- } else {
- throw new \TYPO3\FLOW3\Cache\Exception('Could not set value.', 1232986877);
- }
- }
- /**
- * Loads data from the cache.
- *
- * @param string $entryIdentifier An identifier which describes the cache entry to load
- * @return mixed The cache entry's content as a string or FALSE if the cache entry could not be loaded
- * @api
- */
- public function get($entryIdentifier) {
- $success = FALSE;
- $value = apc_fetch($this->identifierPrefix . $entryIdentifier, $success);
- return ($success ? $value : $success);
- }
- /**
- * Checks if a cache entry with the specified identifier exists.
- *
- * @param string $entryIdentifier An identifier specifying the cache entry
- * @return boolean TRUE if such an entry exists, FALSE if not
- * @api
- */
- public function has($entryIdentifier) {
- $success = FALSE;
- apc_fetch($this->identifierPrefix . $entryIdentifier, $success);
- return $success;
- }
- /**
- * Removes all cache entries matching the specified identifier.
- * Usually this only affects one entry but if - for what reason ever -
- * old entries for the identifier still exist, they are removed as well.
- *
- * @param string $entryIdentifier Specifies the cache entry to remove
- * @return boolean TRUE if (at least) an entry could be removed or FALSE if no entry was found
- * @api
- */
- public function remove($entryIdentifier) {
- $this->removeIdentifierFromAllTags($entryIdentifier);
- return apc_delete($this->identifierPrefix . $entryIdentifier);
- }
- /**
- * Finds and returns all cache entry identifiers which are tagged by the
- * specified tag.
- *
- * @param string $tag The tag to search for
- * @return array An array with identifiers of all matching entries. An empty array if no entries matched
- * @api
- */
- public function findIdentifiersByTag($tag) {
- $success = FALSE;
- $identifiers = apc_fetch($this->identifierPrefix . 'tag_' . $tag, $success);
- if ($success === FALSE) {
- return array();
- } else {
- return (array) $identifiers;
- }
- }
- /**
- * Finds all tags for the given identifier. This function uses reverse tag
- * index to search for tags.
- *
- * @param string $identifier Identifier to find tags by
- * @return array Array with tags
- */
- protected function findTagsByIdentifier($identifier) {
- $success = FALSE;
- $tags = apc_fetch($this->identifierPrefix . 'ident_' . $identifier, $success);
- return ($success ? (array)$tags : array());
- }
- /**
- * Removes all cache entries of this cache.
- *
- * @return void
- * @throws \TYPO3\FLOW3\Cache\Exception
- * @api
- */
- public function flush() {
- if (!$this->cache instanceof \TYPO3\FLOW3\Cache\Frontend\FrontendInterface) {
- throw new \TYPO3\FLOW3\Cache\Exception('Yet no cache frontend has been set via setCache().', 1232986971);
- }
- $this->flushByTag('%APCBE%' . $this->cacheIdentifier);
- }
- /**
- * Removes all cache entries of this cache which are tagged by the specified tag.
- *
- * @param string $tag The tag the entries must have
- * @return void
- * @api
- */
- public function flushByTag($tag) {
- $identifiers = $this->findIdentifiersByTag($tag);
- foreach ($identifiers as $identifier) {
- $this->remove($identifier);
- }
- }
- /**
- * Associates the identifier with the given tags
- *
- * @param string $entryIdentifier
- * @param array $tags
- * @return void
- */
- protected function addIdentifierToTags($entryIdentifier, array $tags) {
- foreach ($tags as $tag) {
- // Update tag-to-identifier index
- $identifiers = $this->findIdentifiersByTag($tag);
- if (array_search($entryIdentifier, $identifiers) === FALSE) {
- $identifiers[] = $entryIdentifier;
- apc_store($this->identifierPrefix . 'tag_' . $tag, $identifiers);
- }
- // Update identifier-to-tag index
- $existingTags = $this->findTagsByIdentifier($entryIdentifier);
- if (array_search($entryIdentifier, $existingTags) === FALSE) {
- apc_store($this->identifierPrefix . 'ident_' . $entryIdentifier, array_merge($existingTags, $tags));
- }
- }
- }
- /**
- * Removes association of the identifier with the given tags
- *
- * @param string $entryIdentifier
- * @return void
- */
- protected function removeIdentifierFromAllTags($entryIdentifier) {
- // Get tags for this identifier
- $tags = $this->findTagsByIdentifier($entryIdentifier);
- // Deassociate tags with this identifier
- foreach ($tags as $tag) {
- $identifiers = $this->findIdentifiersByTag($tag);
- // Formally array_search() below should never return false due to
- // the behavior of findTagsByIdentifier(). But if reverse index is
- // corrupted, we still can get 'false' from array_search(). This is
- // not a problem because we are removing this identifier from
- // anywhere.
- if (($key = array_search($entryIdentifier, $identifiers)) !== FALSE) {
- unset($identifiers[$key]);
- if (count($identifiers)) {
- apc_store($this->identifierPrefix . 'tag_' . $tag, $identifiers);
- } else {
- apc_delete($this->identifierPrefix . 'tag_' . $tag);
- }
- }
- }
- // Clear reverse tag index for this identifier
- apc_delete($this->identifierPrefix . 'ident_' . $entryIdentifier);
- }
- /**
- * Does nothing, as APC does GC itself
- *
- * @return void
- * @api
- */
- public function collectGarbage() {
- }
- }
- ?>