/**
* Interface for caching
*
- * An abstract 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();
+ 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)) {
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('memcached', 'base');
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);
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 = null;
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))) {
+ if (Event::handle('StartCacheSet', array(&$key, &$value, &$flag,
+ &$expiry, &$success))) {
common_log(LOG_INFO, 'Setting cache value for key ' . $key);
+
$this->_items[$key] = $value;
+
$success = true;
- Event::handle('EndCacheSet', array($key, $value, $flag, $expiry));
+
+ Event::handle('EndCacheSet', array($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;