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<?php
/**
* Zend Framework
*
* LICENSE
*
* This source file is subject to the new BSD license that is bundled
* with this package in the file LICENSE.txt.
* It is also available through the world-wide-web at this URL:
* http://framework.zend.com/license/new-bsd
* If you did not receive a copy of the license and are unable to
* obtain it through the world-wide-web, please send an email
* to license@zend.com so we can send you a copy immediately.
*
* @category Zend
* @package Zend_Cache
* @subpackage Zend_Cache_Backend
* @copyright Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
* @version $Id: TwoLevels.php 17741 2009-08-22 02:58:33Z yoshida@zend.co.jp $
*/
/**
* @see Zend_Cache_Backend_ExtendedInterface
*/
require_once 'Zend/Cache/Backend/ExtendedInterface.php';
/**
* @see Zend_Cache_Backend
*/
require_once 'Zend/Cache/Backend.php';
/**
* @package Zend_Cache
* @subpackage Zend_Cache_Backend
* @copyright Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
*/
class Zend_Cache_Backend_TwoLevels extends Zend_Cache_Backend implements Zend_Cache_Backend_ExtendedInterface
{
/**
* Available options
*
* =====> (string) slow_backend :
* - Slow backend name
* - Must implement the Zend_Cache_Backend_ExtendedInterface
* - Should provide a big storage
*
* =====> (string) fast_backend :
* - Flow backend name
* - Must implement the Zend_Cache_Backend_ExtendedInterface
* - Must be much faster than slow_backend
*
* =====> (array) slow_backend_options :
* - Slow backend options (see corresponding backend)
*
* =====> (array) fast_backend_options :
* - Fast backend options (see corresponding backend)
*
* =====> (int) stats_update_factor :
* - Disable / Tune the computation of the fast backend filling percentage
* - When saving a record into cache :
* 1 => systematic computation of the fast backend filling percentage
* x (integer) > 1 => computation of the fast backend filling percentage randomly 1 times on x cache write
*
* =====> (boolean) slow_backend_custom_naming :
* =====> (boolean) fast_backend_custom_naming :
* =====> (boolean) slow_backend_autoload :
* =====> (boolean) fast_backend_autoload :
* - See Zend_Cache::factory() method
*
* =====> (boolean) auto_refresh_fast_cache
* - If true, auto refresh the fast cache when a cache record is hit
*
* @var array available options
*/
protected $_options = array(
'slow_backend' => 'File',
'fast_backend' => 'Apc',
'slow_backend_options' => array(),
'fast_backend_options' => array(),
'stats_update_factor' => 10,
'slow_backend_custom_naming' => false,
'fast_backend_custom_naming' => false,
'slow_backend_autoload' => false,
'fast_backend_autoload' => false,
'auto_refresh_fast_cache' => true
);
/**
* Slow Backend
*
* @var Zend_Cache_Backend
*/
private $_slowBackend;
/**
* Fast Backend
*
* @var Zend_Cache_Backend
*/
private $_fastBackend;
/**
* Cache for the fast backend filling percentage
*
* @var int
*/
private $_fastBackendFillingPercentage = null;
/**
* Constructor
*
* @param array $options Associative array of options
* @throws Zend_Cache_Exception
* @return void
*/
public function __construct(array $options = array())
{
parent::__construct($options);
if ($this->_options['slow_backend'] === null) {
Zend_Cache::throwException('slow_backend option has to set');
}
if ($this->_options['fast_backend'] === null) {
Zend_Cache::throwException('fast_backend option has to set');
}
$this->_slowBackend = Zend_Cache::_makeBackend($this->_options['slow_backend'], $this->_options['slow_backend_options'], $this->_options['slow_backend_custom_naming'], $this->_options['slow_backend_autoload']);
$this->_fastBackend = Zend_Cache::_makeBackend($this->_options['fast_backend'], $this->_options['fast_backend_options'], $this->_options['fast_backend_custom_naming'], $this->_options['fast_backend_autoload']);
if (!in_array('Zend_Cache_Backend_ExtendedInterface', class_implements($this->_slowBackend))) {
Zend_Cache::throwException('slow_backend must implement the Zend_Cache_Backend_ExtendedInterface interface');
}
if (!in_array('Zend_Cache_Backend_ExtendedInterface', class_implements($this->_fastBackend))) {
Zend_Cache::throwException('fast_backend must implement the Zend_Cache_Backend_ExtendedInterface interface');
}
$this->_slowBackend->setDirectives($this->_directives);
$this->_fastBackend->setDirectives($this->_directives);
}
/**
* Test if a cache is available or not (for the given id)
*
* @param string $id cache id
* @return mixed|false (a cache is not available) or "last modified" timestamp (int) of the available cache record
*/
public function test($id)
{
$fastTest = $this->_fastBackend->test($id);
if ($fastTest) {
return $fastTest;
} else {
return $this->_slowBackend->test($id);
}
}
/**
* Save some string datas into a cache record
*
* Note : $data is always "string" (serialization is done by the
* core not by the backend)
*
* @param string $data Datas to cache
* @param string $id Cache id
* @param array $tags Array of strings, the cache record will be tagged by each string entry
* @param int $specificLifetime If != false, set a specific lifetime for this cache record (null => infinite lifetime)
* @param int $priority integer between 0 (very low priority) and 10 (maximum priority) used by some particular backends
* @return boolean true if no problem
*/
public function save($data, $id, $tags = array(), $specificLifetime = false, $priority = 8)
{
$usage = $this->_getFastFillingPercentage('saving');
$boolFast = true;
$lifetime = $this->getLifetime($specificLifetime);
$preparedData = $this->_prepareData($data, $lifetime, $priority);
if (($priority > 0) && (10 * $priority >= $usage)) {
$fastLifetime = $this->_getFastLifetime($lifetime, $priority);
$boolFast = $this->_fastBackend->save($preparedData, $id, array(), $fastLifetime);
}
$boolSlow = $this->_slowBackend->save($preparedData, $id, $tags, $lifetime);
return ($boolFast && $boolSlow);
}
/**
* Test if a cache is available for the given id and (if yes) return it (false else)
*
* Note : return value is always "string" (unserialization is done by the core not by the backend)
*
* @param string $id Cache id
* @param boolean $doNotTestCacheValidity If set to true, the cache validity won't be tested
* @return string|false cached datas
*/
public function load($id, $doNotTestCacheValidity = false)
{
$res = $this->_fastBackend->load($id, $doNotTestCacheValidity);
if ($res === false) {
$res = $this->_slowBackend->load($id, $doNotTestCacheValidity);
if ($res === false) {
// there is no cache at all for this id
return false;
}
}
$array = unserialize($res);
// maybe, we have to refresh the fast cache ?
if ($this->_options['auto_refresh_fast_cache']) {
if ($array['priority'] == 10) {
// no need to refresh the fast cache with priority = 10
return $array['data'];
}
$newFastLifetime = $this->_getFastLifetime($array['lifetime'], $array['priority'], time() - $array['expire']);
// we have the time to refresh the fast cache
$usage = $this->_getFastFillingPercentage('loading');
if (($array['priority'] > 0) && (10 * $array['priority'] >= $usage)) {
// we can refresh the fast cache
$preparedData = $this->_prepareData($array['data'], $array['lifetime'], $array['priority']);
$this->_fastBackend->save($preparedData, $id, array(), $newFastLifetime);
}
}
return $array['data'];
}
/**
* Remove a cache record
*
* @param string $id Cache id
* @return boolean True if no problem
*/
public function remove($id)
{
$boolFast = $this->_fastBackend->remove($id);
$boolSlow = $this->_slowBackend->remove($id);
return $boolFast && $boolSlow;
}
/**
* Clean some cache records
*
* Available modes are :
* Zend_Cache::CLEANING_MODE_ALL (default) => remove all cache entries ($tags is not used)
* Zend_Cache::CLEANING_MODE_OLD => remove too old cache entries ($tags is not used)
* Zend_Cache::CLEANING_MODE_MATCHING_TAG => remove cache entries matching all given tags
* ($tags can be an array of strings or a single string)
* Zend_Cache::CLEANING_MODE_NOT_MATCHING_TAG => remove cache entries not {matching one of the given tags}
* ($tags can be an array of strings or a single string)
* Zend_Cache::CLEANING_MODE_MATCHING_ANY_TAG => remove cache entries matching any given tags
* ($tags can be an array of strings or a single string)
*
* @param string $mode Clean mode
* @param array $tags Array of tags
* @throws Zend_Cache_Exception
* @return boolean true if no problem
*/
public function clean($mode = Zend_Cache::CLEANING_MODE_ALL, $tags = array())
{
switch($mode) {
case Zend_Cache::CLEANING_MODE_ALL:
$boolFast = $this->_fastBackend->clean(Zend_Cache::CLEANING_MODE_ALL);
$boolSlow = $this->_slowBackend->clean(Zend_Cache::CLEANING_MODE_ALL);
return $boolFast && $boolSlow;
break;
case Zend_Cache::CLEANING_MODE_OLD:
return $this->_slowBackend->clean(Zend_Cache::CLEANING_MODE_OLD);
case Zend_Cache::CLEANING_MODE_MATCHING_TAG:
$ids = $this->_slowBackend->getIdsMatchingTags($tags);
$res = true;
foreach ($ids as $id) {
$bool = $this->remove($id);
$res = $res && $bool;
}
return $res;
break;
case Zend_Cache::CLEANING_MODE_NOT_MATCHING_TAG:
$ids = $this->_slowBackend->getIdsNotMatchingTags($tags);
$res = true;
foreach ($ids as $id) {
$bool = $this->remove($id);
$res = $res && $bool;
}
return $res;
break;
case Zend_Cache::CLEANING_MODE_MATCHING_ANY_TAG:
$ids = $this->_slowBackend->getIdsMatchingAnyTags($tags);
$res = true;
foreach ($ids as $id) {
$bool = $this->remove($id);
$res = $res && $bool;
}
return $res;
break;
default:
Zend_Cache::throwException('Invalid mode for clean() method');
break;
}
}
/**
* Return an array of stored cache ids
*
* @return array array of stored cache ids (string)
*/
public function getIds()
{
return $this->_slowBackend->getIds();
}
/**
* Return an array of stored tags
*
* @return array array of stored tags (string)
*/
public function getTags()
{
return $this->_slowBackend->getTags();
}
/**
* Return an array of stored cache ids which match given tags
*
* In case of multiple tags, a logical AND is made between tags
*
* @param array $tags array of tags
* @return array array of matching cache ids (string)
*/
public function getIdsMatchingTags($tags = array())
{
return $this->_slowBackend->getIdsMatchingTags($tags);
}
/**
* Return an array of stored cache ids which don't match given tags
*
* In case of multiple tags, a logical OR is made between tags
*
* @param array $tags array of tags
* @return array array of not matching cache ids (string)
*/
public function getIdsNotMatchingTags($tags = array())
{
return $this->_slowBackend->getIdsNotMatchingTags($tags);
}
/**
* Return an array of stored cache ids which match any given tags
*
* In case of multiple tags, a logical AND is made between tags
*
* @param array $tags array of tags
* @return array array of any matching cache ids (string)
*/
public function getIdsMatchingAnyTags($tags = array())
{
return $this->_slowBackend->getIdsMatchingAnyTags($tags);
}
/**
* Return the filling percentage of the backend storage
*
* @return int integer between 0 and 100
*/
public function getFillingPercentage()
{
return $this->_slowBackend->getFillingPercentage();
}
/**
* Return an array of metadatas for the given cache id
*
* The array must include these keys :
* - expire : the expire timestamp
* - tags : a string array of tags
* - mtime : timestamp of last modification time
*
* @param string $id cache id
* @return array array of metadatas (false if the cache id is not found)
*/
public function getMetadatas($id)
{
return $this->_slowBackend->getMetadatas($id);
}
/**
* Give (if possible) an extra lifetime to the given cache id
*
* @param string $id cache id
* @param int $extraLifetime
* @return boolean true if ok
*/
public function touch($id, $extraLifetime)
{
return $this->_slowBackend->touch($id, $extraLifetime);
}
/**
* Return an associative array of capabilities (booleans) of the backend
*
* The array must include these keys :
* - automatic_cleaning (is automating cleaning necessary)
* - tags (are tags supported)
* - expired_read (is it possible to read expired cache records
* (for doNotTestCacheValidity option for example))
* - priority does the backend deal with priority when saving
* - infinite_lifetime (is infinite lifetime can work with this backend)
* - get_list (is it possible to get the list of cache ids and the complete list of tags)
*
* @return array associative of with capabilities
*/
public function getCapabilities()
{
$slowBackendCapabilities = $this->_slowBackend->getCapabilities();
return array(
'automatic_cleaning' => $slowBackendCapabilities['automatic_cleaning'],
'tags' => $slowBackendCapabilities['tags'],
'expired_read' => $slowBackendCapabilities['expired_read'],
'priority' => $slowBackendCapabilities['priority'],
'infinite_lifetime' => $slowBackendCapabilities['infinite_lifetime'],
'get_list' => $slowBackendCapabilities['get_list']
);
}
/**
* Prepare a serialized array to store datas and metadatas informations
*
* @param string $data data to store
* @param int $lifetime original lifetime
* @param int $priority priority
* @return string serialize array to store into cache
*/
private function _prepareData($data, $lifetime, $priority)
{
$lt = $lifetime;
if ($lt === null) {
$lt = 9999999999;
}
return serialize(array(
'data' => $data,
'lifetime' => $lifetime,
'expire' => time() + $lt,
'priority' => $priority
));
}
/**
* Compute and return the lifetime for the fast backend
*
* @param int $lifetime original lifetime
* @param int $priority priority
* @param int $maxLifetime maximum lifetime
* @return int lifetime for the fast backend
*/
private function _getFastLifetime($lifetime, $priority, $maxLifetime = null)
{
if ($lifetime === null) {
// if lifetime is null, we have an infinite lifetime
// we need to use arbitrary lifetimes
$fastLifetime = (int) (2592000 / (11 - $priority));
} else {
$fastLifetime = (int) ($lifetime / (11 - $priority));
}
if (($maxLifetime !== null) && ($maxLifetime >= 0)) {
if ($fastLifetime > $maxLifetime) {
return $maxLifetime;
}
}
return $fastLifetime;
}
/**
* PUBLIC METHOD FOR UNIT TESTING ONLY !
*
* Force a cache record to expire
*
* @param string $id cache id
*/
public function ___expire($id)
{
$this->_fastBackend->remove($id);
$this->_slowBackend->___expire($id);
}
private function _getFastFillingPercentage($mode)
{
if ($mode == 'saving') {
// mode saving
if ($this->_fastBackendFillingPercentage === null) {
$this->_fastBackendFillingPercentage = $this->_fastBackend->getFillingPercentage();
} else {
$rand = rand(1, $this->_options['stats_update_factor']);
if ($rand == 1) {
// we force a refresh
$this->_fastBackendFillingPercentage = $this->_fastBackend->getFillingPercentage();
}
}
} else {
// mode loading
// we compute the percentage only if it's not available in cache
if ($this->_fastBackendFillingPercentage === null) {
$this->_fastBackendFillingPercentage = $this->_fastBackend->getFillingPercentage();
}
}
return $this->_fastBackendFillingPercentage;
}
}
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