diff options
Diffstat (limited to 'lib/cache.php')
| -rw-r--r-- | lib/cache.php | 182 |
1 files changed, 182 insertions, 0 deletions
diff --git a/lib/cache.php b/lib/cache.php new file mode 100644 index 000000000..b7b34c050 --- /dev/null +++ b/lib/cache.php @@ -0,0 +1,182 @@ +<?php +/** + * StatusNet, the distributed open-source microblogging tool + * + * Cache interface plus default in-memory cache implementation + * + * PHP version 5 + * + * LICENCE: This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU Affero General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU Affero General Public License for more details. + * + * You should have received a copy of the GNU Affero General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + * @category Cache + * @package StatusNet + * @author Evan Prodromou <evan@status.net> + * @copyright 2009 StatusNet, Inc. + * @license http://www.fsf.org/licensing/licenses/agpl-3.0.html GNU Affero General Public License version 3.0 + * @link http://status.net/ + */ + +/** + * Interface for caching + * + * An abstract interface for caching. Because we originally used the + * Memcache plugin directly, the interface uses a small subset of the + * Memcache interface. + * + * @category Cache + * @package StatusNet + * @author Evan Prodromou <evan@status.net> + * @copyright 2009 StatusNet, Inc. + * @license http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0 + * @link http://status.net/ + */ + +class Cache +{ + var $_items = array(); + static $_inst = null; + + /** + * Singleton constructor + * + * Use this to get the singleton instance of Cache. + * + * @return Cache cache object + */ + + static function instance() + { + if (is_null(self::$_inst)) { + self::$_inst = new Cache(); + } + + return self::$_inst; + } + + /** + * Create a cache key from input text + * + * Builds a cache key from input text. Helps to namespace + * the cache area (if shared with other applications or sites) + * and prevent conflicts. + * + * @param string $extra the real part of the key + * + * @return string full key + */ + + static function key($extra) + { + $base_key = common_config('cache', 'base'); + + if (empty($base_key)) { + $base_key = common_keyize(common_config('site', 'name')); + } + + return 'statusnet:' . $base_key . ':' . $extra; + } + + /** + * Make a string suitable for use as a key + * + * Useful for turning primary keys of tables into cache keys. + * + * @param string $str string to turn into a key + * + * @return string keyized string + */ + + static function keyize($str) + { + $str = strtolower($str); + $str = preg_replace('/\s/', '_', $str); + return $str; + } + + /** + * Get a value associated with a key + * + * The value should have been set previously. + * + * @param string $key Lookup key + * + * @return string retrieved value or null if unfound + */ + + function get($key) + { + $value = false; + + if (Event::handle('StartCacheGet', array(&$key, &$value))) { + if (array_key_exists($key, $this->_items)) { + $value = unserialize($this->_items[$key]); + } + Event::handle('EndCacheGet', array($key, &$value)); + } + + return $value; + } + + /** + * Set the value associated with a key + * + * @param string $key The key to use for lookups + * @param string $value The value to store + * @param integer $flag Flags to use, mostly ignored + * @param integer $expiry Expiry value, mostly ignored + * + * @return boolean success flag + */ + + function set($key, $value, $flag=null, $expiry=null) + { + $success = false; + + if (Event::handle('StartCacheSet', array(&$key, &$value, &$flag, + &$expiry, &$success))) { + + $this->_items[$key] = serialize($value); + + $success = true; + + Event::handle('EndCacheSet', array($key, $value, $flag, + $expiry)); + } + + return $success; + } + + /** + * Delete the value associated with a key + * + * @param string $key Key to delete + * + * @return boolean success flag + */ + + function delete($key) + { + $success = false; + + if (Event::handle('StartCacheDelete', array(&$key, &$success))) { + if (array_key_exists($key, $this->_items)) { + unset($this->_items[$key]); + } + $success = true; + Event::handle('EndCacheDelete', array($key)); + } + + return $success; + } +} |