1: <?php
  2: /**
  3:  * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
  4:  * Copyright 2005-2012, Cake Software Foundation, Inc. (http://cakefoundation.org)
  5:  *
  6:  * Licensed under The MIT License
  7:  * Redistributions of files must retain the above copyright notice.
  8:  *
  9:  * @copyright     Copyright 2005-2012, Cake Software Foundation, Inc. (http://cakefoundation.org)
 10:  * @link          http://cakephp.org CakePHP(tm) Project
 11:  * @package       Cake.Cache
 12:  * @since         CakePHP(tm) v 1.2.0.4933
 13:  * @license       MIT License (http://www.opensource.org/licenses/mit-license.php)
 14:  */
 15: 
 16: /**
 17:  * Storage engine for CakePHP caching
 18:  *
 19:  * @package       Cake.Cache
 20:  */
 21: abstract class CacheEngine {
 22: 
 23: /**
 24:  * Settings of current engine instance
 25:  *
 26:  * @var array
 27:  */
 28:     public $settings = array();
 29: 
 30: /**
 31:  * Initialize the cache engine
 32:  *
 33:  * Called automatically by the cache frontend
 34:  *
 35:  * @param array $settings Associative array of parameters for the engine
 36:  * @return boolean True if the engine has been successfully initialized, false if not
 37:  */
 38:     public function init($settings = array()) {
 39:         $this->settings = array_merge(
 40:             array('prefix' => 'cake_', 'duration' => 3600, 'probability' => 100),
 41:             $this->settings,
 42:             $settings
 43:         );
 44:         if (!is_numeric($this->settings['duration'])) {
 45:             $this->settings['duration'] = strtotime($this->settings['duration']) - time();
 46:         }
 47:         return true;
 48:     }
 49: 
 50: /**
 51:  * Garbage collection
 52:  *
 53:  * Permanently remove all expired and deleted data
 54:  * @return void
 55:  */
 56:     public function gc() {
 57:     }
 58: 
 59: /**
 60:  * Write value for a key into cache
 61:  *
 62:  * @param string $key Identifier for the data
 63:  * @param mixed $value Data to be cached
 64:  * @param mixed $duration How long to cache for.
 65:  * @return boolean True if the data was successfully cached, false on failure
 66:  */
 67:     abstract public function write($key, $value, $duration);
 68: 
 69: /**
 70:  * Read a key from the cache
 71:  *
 72:  * @param string $key Identifier for the data
 73:  * @return mixed The cached data, or false if the data doesn't exist, has expired, or if there was an error fetching it
 74:  */
 75:     abstract public function read($key);
 76: 
 77: /**
 78:  * Increment a number under the key and return incremented value
 79:  *
 80:  * @param string $key Identifier for the data
 81:  * @param integer $offset How much to add
 82:  * @return New incremented value, false otherwise
 83:  */
 84:     abstract public function increment($key, $offset = 1);
 85: 
 86: /**
 87:  * Decrement a number under the key and return decremented value
 88:  *
 89:  * @param string $key Identifier for the data
 90:  * @param integer $offset How much to subtract
 91:  * @return New incremented value, false otherwise
 92:  */
 93:     abstract public function decrement($key, $offset = 1);
 94: 
 95: /**
 96:  * Delete a key from the cache
 97:  *
 98:  * @param string $key Identifier for the data
 99:  * @return boolean True if the value was successfully deleted, false if it didn't exist or couldn't be removed
100:  */
101:     abstract public function delete($key);
102: 
103: /**
104:  * Delete all keys from the cache
105:  *
106:  * @param boolean $check if true will check expiration, otherwise delete all
107:  * @return boolean True if the cache was successfully cleared, false otherwise
108:  */
109:     abstract public function clear($check);
110: 
111: /**
112:  * Cache Engine settings
113:  *
114:  * @return array settings
115:  */
116:     public function settings() {
117:         return $this->settings;
118:     }
119: 
120: /**
121:  * Generates a safe key for use with cache engine storage engines.
122:  *
123:  * @param string $key the key passed over
124:  * @return mixed string $key or false
125:  */
126:     public function key($key) {
127:         if (empty($key)) {
128:             return false;
129:         }
130:         $key = Inflector::underscore(str_replace(array(DS, '/', '.'), '_', strval($key)));
131:         return $key;
132:     }
133: 
134: }
135: