library/Zend/Cache/Backend/TwoLevels.php

   1 <?php
   2 /**
   3  * Zend Framework
   4  *
   5  * LICENSE
   6  *
   7  * This source file is subject to the new BSD license that is bundled
   8  * with this package in the file LICENSE.txt.
   9  * It is also available through the world-wide-web at this URL:
  10  * http://framework.zend.com/license/new-bsd
  11  * If you did not receive a copy of the license and are unable to
  12  * obtain it through the world-wide-web, please send an email
  13  * to license@zend.com so we can send you a copy immediately.
  14  *
  15  * @category   Zend
  16  * @package    Zend_Cache
  17  * @subpackage Zend_Cache_Backend
  18  * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
  19  * @license    http://framework.zend.com/license/new-bsd     New BSD License
  20  * @version    $Id: TwoLevels.php 17741 2009-08-22 02:58:33Z yoshida@zend.co.jp $
  21  */
  22
  23
  24 /**
  25  * @see Zend_Cache_Backend_ExtendedInterface
  26  */
  27 require_once 'Zend/Cache/Backend/ExtendedInterface.php';
  28
  29 /**
  30  * @see Zend_Cache_Backend
  31  */
  32 require_once 'Zend/Cache/Backend.php';
  33
  34
  35 /**
  36  * @package    Zend_Cache
  37  * @subpackage Zend_Cache_Backend
  38  * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
  39  * @license    http://framework.zend.com/license/new-bsd     New BSD License
  40  */
  41
  42 class Zend_Cache_Backend_TwoLevels extends Zend_Cache_Backend implements Zend_Cache_Backend_ExtendedInterface
  43 {
  44     /**
  45      * Available options
  46      *
  47      * =====> (string) slow_backend :
  48      * - Slow backend name
  49      * - Must implement the Zend_Cache_Backend_ExtendedInterface
  50      * - Should provide a big storage
  51      *
  52      * =====> (string) fast_backend :
  53      * - Flow backend name
  54      * - Must implement the Zend_Cache_Backend_ExtendedInterface
  55      * - Must be much faster than slow_backend
  56      *
  57      * =====> (array) slow_backend_options :
  58      * - Slow backend options (see corresponding backend)
  59      *
  60      * =====> (array) fast_backend_options :
  61      * - Fast backend options (see corresponding backend)
  62      *
  63      * =====> (int) stats_update_factor :
  64      * - Disable / Tune the computation of the fast backend filling percentage
  65      * - When saving a record into cache :
  66      *     1               => systematic computation of the fast backend filling percentage
  67      *     x (integer) > 1 => computation of the fast backend filling percentage randomly 1 times on x cache write
  68      *
  69      * =====> (boolean) slow_backend_custom_naming :
  70      * =====> (boolean) fast_backend_custom_naming :
  71      * =====> (boolean) slow_backend_autoload :
  72      * =====> (boolean) fast_backend_autoload :
  73      * - See Zend_Cache::factory() method
  74      *
  75      * =====> (boolean) auto_refresh_fast_cache
  76      * - If true, auto refresh the fast cache when a cache record is hit
  77      *
  78      * @var array available options
  79      */
  80     protected $_options = array(
  81         'slow_backend' => 'File',
  82         'fast_backend' => 'Apc',
  83         'slow_backend_options' => array(),
  84         'fast_backend_options' => array(),
  85         'stats_update_factor' => 10,
  86         'slow_backend_custom_naming' => false,
  87         'fast_backend_custom_naming' => false,
  88         'slow_backend_autoload' => false,
  89         'fast_backend_autoload' => false,
  90         'auto_refresh_fast_cache' => true
  91     );
  92
  93     /**
  94      * Slow Backend
  95      *
  96      * @var Zend_Cache_Backend
  97      */
  98     private $_slowBackend;
  99
 100     /**
 101      * Fast Backend
 102      *
 103      * @var Zend_Cache_Backend
 104      */
 105     private $_fastBackend;
 106
 107     /**
 108      * Cache for the fast backend filling percentage
 109      *
 110      * @var int
 111      */
 112     private $_fastBackendFillingPercentage = null;
 113
 114     /**
 115      * Constructor
 116      *
 117      * @param  array $options Associative array of options
 118      * @throws Zend_Cache_Exception
 119      * @return void
 120      */
 121     public function __construct(array $options = array())
 122     {
 123         parent::__construct($options);
 124         if ($this->_options['slow_backend'] === null) {
 125             Zend_Cache::throwException('slow_backend option has to set');
 126         }
 127         if ($this->_options['fast_backend'] === null) {
 128             Zend_Cache::throwException('fast_backend option has to set');
 129         }
 130         $this->_slowBackend = Zend_Cache::_makeBackend($this->_options['slow_backend'], $this->_options['slow_backend_options'], $this->_options['slow_backend_custom_naming'], $this->_options['slow_backend_autoload']);
 131         $this->_fastBackend = Zend_Cache::_makeBackend($this->_options['fast_backend'], $this->_options['fast_backend_options'], $this->_options['fast_backend_custom_naming'], $this->_options['fast_backend_autoload']);
 132         if (!in_array('Zend_Cache_Backend_ExtendedInterface', class_implements($this->_slowBackend))) {
 133             Zend_Cache::throwException('slow_backend must implement the Zend_Cache_Backend_ExtendedInterface interface');
 134         }
 135         if (!in_array('Zend_Cache_Backend_ExtendedInterface', class_implements($this->_fastBackend))) {
 136             Zend_Cache::throwException('fast_backend must implement the Zend_Cache_Backend_ExtendedInterface interface');
 137         }
 138         $this->_slowBackend->setDirectives($this->_directives);
 139         $this->_fastBackend->setDirectives($this->_directives);
 140     }
 141
 142     /**
 143      * Test if a cache is available or not (for the given id)
 144      *
 145      * @param  string $id cache id
 146      * @return mixed|false (a cache is not available) or "last modified" timestamp (int) of the available cache record
 147      */
 148     public function test($id)
 149     {
 150         $fastTest = $this->_fastBackend->test($id);
 151         if ($fastTest) {
 152             return $fastTest;
 153         } else {
 154             return $this->_slowBackend->test($id);
 155         }
 156     }
 157
 158     /**
 159      * Save some string datas into a cache record
 160      *
 161      * Note : $data is always "string" (serialization is done by the
 162      * core not by the backend)
 163      *
 164      * @param  string $data            Datas to cache
 165      * @param  string $id              Cache id
 166      * @param  array $tags             Array of strings, the cache record will be tagged by each string entry
 167      * @param  int   $specificLifetime If != false, set a specific lifetime for this cache record (null => infinite lifetime)
 168      * @param  int   $priority         integer between 0 (very low priority) and 10 (maximum priority) used by some particular backends
 169      * @return boolean true if no problem
 170      */
 171     public function save($data, $id, $tags = array(), $specificLifetime = false, $priority = 8)
 172     {
 173         $usage = $this->_getFastFillingPercentage('saving');
 174         $boolFast = true;
 175         $lifetime = $this->getLifetime($specificLifetime);
 176         $preparedData = $this->_prepareData($data, $lifetime, $priority);
 177         if (($priority > 0) && (10 * $priority >= $usage)) {
 178             $fastLifetime = $this->_getFastLifetime($lifetime, $priority);
 179             $boolFast = $this->_fastBackend->save($preparedData, $id, array(), $fastLifetime);
 180         }
 181         $boolSlow = $this->_slowBackend->save($preparedData, $id, $tags, $lifetime);
 182         return ($boolFast && $boolSlow);
 183     }
 184
 185     /**
 186      * Test if a cache is available for the given id and (if yes) return it (false else)
 187      *
 188      * Note : return value is always "string" (unserialization is done by the core not by the backend)
 189      *
 190      * @param  string  $id                     Cache id
 191      * @param  boolean $doNotTestCacheValidity If set to true, the cache validity won't be tested
 192      * @return string|false cached datas
 193      */
 194     public function load($id, $doNotTestCacheValidity = false)
 195     {
 196         $res = $this->_fastBackend->load($id, $doNotTestCacheValidity);
 197         if ($res === false) {
 198             $res = $this->_slowBackend->load($id, $doNotTestCacheValidity);
 199             if ($res === false) {
 200                 // there is no cache at all for this id
 201                 return false;
 202             }
 203         }
 204         $array = unserialize($res);
 205         // maybe, we have to refresh the fast cache ?
 206         if ($this->_options['auto_refresh_fast_cache']) {
 207             if ($array['priority'] == 10) {
 208                 // no need to refresh the fast cache with priority = 10
 209                 return $array['data'];
 210             }
 211             $newFastLifetime = $this->_getFastLifetime($array['lifetime'], $array['priority'], time() - $array['expire']);
 212             // we have the time to refresh the fast cache
 213             $usage = $this->_getFastFillingPercentage('loading');
 214             if (($array['priority'] > 0) && (10 * $array['priority'] >= $usage)) {
 215                 // we can refresh the fast cache
 216                 $preparedData = $this->_prepareData($array['data'], $array['lifetime'], $array['priority']);
 217                 $this->_fastBackend->save($preparedData, $id, array(), $newFastLifetime);
 218             }
 219         }
 220         return $array['data'];
 221     }
 222
 223     /**
 224      * Remove a cache record
 225      *
 226      * @param  string $id Cache id
 227      * @return boolean True if no problem
 228      */
 229     public function remove($id)
 230     {
 231         $boolFast = $this->_fastBackend->remove($id);
 232         $boolSlow = $this->_slowBackend->remove($id);
 233         return $boolFast && $boolSlow;
 234     }
 235
 236     /**
 237      * Clean some cache records
 238      *
 239      * Available modes are :
 240      * Zend_Cache::CLEANING_MODE_ALL (default)    => remove all cache entries ($tags is not used)
 241      * Zend_Cache::CLEANING_MODE_OLD              => remove too old cache entries ($tags is not used)
 242      * Zend_Cache::CLEANING_MODE_MATCHING_TAG     => remove cache entries matching all given tags
 243      *                                               ($tags can be an array of strings or a single string)
 244      * Zend_Cache::CLEANING_MODE_NOT_MATCHING_TAG => remove cache entries not {matching one of the given tags}
 245      *                                               ($tags can be an array of strings or a single string)
 246      * Zend_Cache::CLEANING_MODE_MATCHING_ANY_TAG => remove cache entries matching any given tags
 247      *                                               ($tags can be an array of strings or a single string)
 248      *
 249      * @param  string $mode Clean mode
 250      * @param  array  $tags Array of tags
 251      * @throws Zend_Cache_Exception
 252      * @return boolean true if no problem
 253      */
 254     public function clean($mode = Zend_Cache::CLEANING_MODE_ALL, $tags = array())
 255     {
 256         switch($mode) {
 257             case Zend_Cache::CLEANING_MODE_ALL:
 258                 $boolFast = $this->_fastBackend->clean(Zend_Cache::CLEANING_MODE_ALL);
 259                 $boolSlow = $this->_slowBackend->clean(Zend_Cache::CLEANING_MODE_ALL);
 260                 return $boolFast && $boolSlow;
 261                 break;
 262             case Zend_Cache::CLEANING_MODE_OLD:
 263                 return $this->_slowBackend->clean(Zend_Cache::CLEANING_MODE_OLD);
 264             case Zend_Cache::CLEANING_MODE_MATCHING_TAG:
 265                 $ids = $this->_slowBackend->getIdsMatchingTags($tags);
 266                 $res = true;
 267                 foreach ($ids as $id) {
 268                     $bool = $this->remove($id);
 269                     $res = $res && $bool;
 270                 }
 271                 return $res;
 272                 break;
 273             case Zend_Cache::CLEANING_MODE_NOT_MATCHING_TAG:
 274                 $ids = $this->_slowBackend->getIdsNotMatchingTags($tags);
 275                 $res = true;
 276                 foreach ($ids as $id) {
 277                     $bool = $this->remove($id);
 278                     $res = $res && $bool;
 279                 }
 280                 return $res;
 281                 break;
 282             case Zend_Cache::CLEANING_MODE_MATCHING_ANY_TAG:
 283                 $ids = $this->_slowBackend->getIdsMatchingAnyTags($tags);
 284                 $res = true;
 285                 foreach ($ids as $id) {
 286                     $bool = $this->remove($id);
 287                     $res = $res && $bool;
 288                 }
 289                 return $res;
 290                 break;
 291             default:
 292                 Zend_Cache::throwException('Invalid mode for clean() method');
 293                 break;
 294         }
 295     }
 296
 297     /**
 298      * Return an array of stored cache ids
 299      *
 300      * @return array array of stored cache ids (string)
 301      */
 302     public function getIds()
 303     {
 304         return $this->_slowBackend->getIds();
 305     }
 306
 307     /**
 308      * Return an array of stored tags
 309      *
 310      * @return array array of stored tags (string)
 311      */
 312     public function getTags()
 313     {
 314         return $this->_slowBackend->getTags();
 315     }
 316
 317     /**
 318      * Return an array of stored cache ids which match given tags
 319      *
 320      * In case of multiple tags, a logical AND is made between tags
 321      *
 322      * @param array $tags array of tags
 323      * @return array array of matching cache ids (string)
 324      */
 325     public function getIdsMatchingTags($tags = array())
 326     {
 327         return $this->_slowBackend->getIdsMatchingTags($tags);
 328     }
 329
 330     /**
 331      * Return an array of stored cache ids which don't match given tags
 332      *
 333      * In case of multiple tags, a logical OR is made between tags
 334      *
 335      * @param array $tags array of tags
 336      * @return array array of not matching cache ids (string)
 337      */
 338     public function getIdsNotMatchingTags($tags = array())
 339     {
 340         return $this->_slowBackend->getIdsNotMatchingTags($tags);
 341     }
 342
 343     /**
 344      * Return an array of stored cache ids which match any given tags
 345      *
 346      * In case of multiple tags, a logical AND is made between tags
 347      *
 348      * @param array $tags array of tags
 349      * @return array array of any matching cache ids (string)
 350      */
 351     public function getIdsMatchingAnyTags($tags = array())
 352     {
 353         return $this->_slowBackend->getIdsMatchingAnyTags($tags);
 354     }
 355
 356
 357     /**
 358      * Return the filling percentage of the backend storage
 359      *
 360      * @return int integer between 0 and 100
 361      */
 362     public function getFillingPercentage()
 363     {
 364         return $this->_slowBackend->getFillingPercentage();
 365     }
 366
 367     /**
 368      * Return an array of metadatas for the given cache id
 369      *
 370      * The array must include these keys :
 371      * - expire : the expire timestamp
 372      * - tags : a string array of tags
 373      * - mtime : timestamp of last modification time
 374      *
 375      * @param string $id cache id
 376      * @return array array of metadatas (false if the cache id is not found)
 377      */
 378     public function getMetadatas($id)
 379     {
 380         return $this->_slowBackend->getMetadatas($id);
 381     }
 382
 383     /**
 384      * Give (if possible) an extra lifetime to the given cache id
 385      *
 386      * @param string $id cache id
 387      * @param int $extraLifetime
 388      * @return boolean true if ok
 389      */
 390     public function touch($id, $extraLifetime)
 391     {
 392         return $this->_slowBackend->touch($id, $extraLifetime);
 393     }
 394
 395     /**
 396      * Return an associative array of capabilities (booleans) of the backend
 397      *
 398      * The array must include these keys :
 399      * - automatic_cleaning (is automating cleaning necessary)
 400      * - tags (are tags supported)
 401      * - expired_read (is it possible to read expired cache records
 402      *                 (for doNotTestCacheValidity option for example))
 403      * - priority does the backend deal with priority when saving
 404      * - infinite_lifetime (is infinite lifetime can work with this backend)
 405      * - get_list (is it possible to get the list of cache ids and the complete list of tags)
 406      *
 407      * @return array associative of with capabilities
 408      */
 409     public function getCapabilities()
 410     {
 411         $slowBackendCapabilities = $this->_slowBackend->getCapabilities();
 412         return array(
 413             'automatic_cleaning' => $slowBackendCapabilities['automatic_cleaning'],
 414             'tags' => $slowBackendCapabilities['tags'],
 415             'expired_read' => $slowBackendCapabilities['expired_read'],
 416             'priority' => $slowBackendCapabilities['priority'],
 417             'infinite_lifetime' => $slowBackendCapabilities['infinite_lifetime'],
 418             'get_list' => $slowBackendCapabilities['get_list']
 419         );
 420     }
 421
 422     /**
 423      * Prepare a serialized array to store datas and metadatas informations
 424      *
 425      * @param string $data data to store
 426      * @param int $lifetime original lifetime
 427      * @param int $priority priority
 428      * @return string serialize array to store into cache
 429      */
 430     private function _prepareData($data, $lifetime, $priority)
 431     {
 432         $lt = $lifetime;
 433         if ($lt === null) {
 434             $lt = 9999999999;
 435         }
 436         return serialize(array(
 437             'data' => $data,
 438             'lifetime' => $lifetime,
 439             'expire' => time() + $lt,
 440             'priority' => $priority
 441         ));
 442     }
 443
 444     /**
 445      * Compute and return the lifetime for the fast backend
 446      *
 447      * @param int $lifetime original lifetime
 448      * @param int $priority priority
 449      * @param int $maxLifetime maximum lifetime
 450      * @return int lifetime for the fast backend
 451      */
 452     private function _getFastLifetime($lifetime, $priority, $maxLifetime = null)
 453     {
 454         if ($lifetime === null) {
 455             // if lifetime is null, we have an infinite lifetime
 456             // we need to use arbitrary lifetimes
 457             $fastLifetime = (int) (2592000 / (11 - $priority));
 458         } else {
 459             $fastLifetime = (int) ($lifetime / (11 - $priority));
 460         }
 461         if (($maxLifetime !== null) && ($maxLifetime >= 0)) {
 462             if ($fastLifetime > $maxLifetime) {
 463                 return $maxLifetime;
 464             }
 465         }
 466         return $fastLifetime;
 467     }
 468
 469     /**
 470      * PUBLIC METHOD FOR UNIT TESTING ONLY !
 471      *
 472      * Force a cache record to expire
 473      *
 474      * @param string $id cache id
 475      */
 476     public function ___expire($id)
 477     {
 478         $this->_fastBackend->remove($id);
 479         $this->_slowBackend->___expire($id);
 480     }
 481
 482     private function _getFastFillingPercentage($mode)
 483     {
 484
 485         if ($mode == 'saving') {
 486             // mode saving
 487             if ($this->_fastBackendFillingPercentage === null) {
 488                 $this->_fastBackendFillingPercentage = $this->_fastBackend->getFillingPercentage();
 489             } else {
 490                 $rand = rand(1, $this->_options['stats_update_factor']);
 491                 if ($rand == 1) {
 492                     // we force a refresh
 493                     $this->_fastBackendFillingPercentage = $this->_fastBackend->getFillingPercentage();
 494                 }
 495             }
 496         } else {
 497             // mode loading
 498             // we compute the percentage only if it's not available in cache
 499             if ($this->_fastBackendFillingPercentage === null) {
 500                 $this->_fastBackendFillingPercentage = $this->_fastBackend->getFillingPercentage();
 501             }
 502         }
 503         return $this->_fastBackendFillingPercentage;
 504     }
 505
 506 }