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<?php
// +-----------------------------------------------------------------------+
// | Piwigo - a PHP based photo gallery |
// +-----------------------------------------------------------------------+
// | Copyright(C) 2008-2016 Piwigo Team http://piwigo.org |
// | Copyright(C) 2003-2008 PhpWebGallery Team http://phpwebgallery.net |
// | Copyright(C) 2002-2003 Pierrick LE GALL http://le-gall.net/pierrick |
// +-----------------------------------------------------------------------+
// | This program is free software; you can redistribute it and/or modify |
// | it under the terms of the GNU General Public License as published by |
// | the Free Software Foundation |
// | |
// | 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 |
// | General Public License for more details. |
// | |
// | You should have received a copy of the GNU General Public License |
// | along with this program; if not, write to the Free Software |
// | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, |
// | USA. |
// +-----------------------------------------------------------------------+
/**
Provides a persistent cache mechanism across multiple page loads/sessions etc...
*/
abstract class PersistentCache
{
var $default_lifetime = 86400;
protected $instance_key = PHPWG_VERSION;
/**
@return a key that can be safely be used with get/set methods
*/
function make_key($key)
{
if ( is_array($key) )
{
$key = implode('&', $key);
}
$key .= $this->instance_key;
return md5($key);
}
/**
Searches for a key in the persistent cache and fills corresponding value.
@param string $key
@param out mixed $value
@return false if the $key is not found in cache ($value is not modified in this case)
*/
abstract function get($key, &$value);
/**
Sets a key/value pair in the persistent cache.
@param string $key - it should be the return value of make_key function
@param mixed $value
@param int $lifetime
@return false on error
*/
abstract function set($key, $value, $lifetime=null);
/**
Purge the persistent cache.
@param boolean $all - if false only expired items will be purged
*/
abstract function purge($all);
}
/**
Implementation of a persistent cache using files.
*/
class PersistentFileCache extends PersistentCache
{
private $dir;
function __construct()
{
global $conf;
$this->dir = PHPWG_ROOT_PATH.$conf['data_location'].'cache/';
}
function get($key, &$value)
{
$loaded = @file_get_contents($this->dir.$key.'.cache');
if ($loaded !== false && ($loaded=unserialize($loaded)) !== false)
{
if ($loaded['expire'] > time())
{
$value = $loaded['data'];
return true;
}
}
return false;
}
function set($key, $value, $lifetime=null)
{
if ($lifetime === null)
{
$lifetime = $this->default_lifetime;
}
if (rand() % 97 == 0)
{
$this->purge(false);
}
$serialized = serialize( array(
'expire' => time() + $lifetime,
'data' => $value
));
if (false === @file_put_contents($this->dir.$key.'.cache', $serialized))
{
mkgetdir($this->dir, MKGETDIR_DEFAULT&~MKGETDIR_DIE_ON_ERROR);
if (false === @file_put_contents($this->dir.$key.'.cache', $serialized))
{
return false;
}
}
return true;
}
function purge($all)
{
$files = glob($this->dir.'*.cache');
if (empty($files))
{
return;
}
$limit = time() - $this->default_lifetime;
foreach ($files as $file)
{
if ($all || @filemtime($file) < $limit)
@unlink($file);
}
}
}
?>
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