egroupware/api/src/Cache/Apcu.php

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<?php
/**
* EGroupware API: Caching provider storing data in PHP's APCu extension
*
* @link http://www.egroupware.org
* @license http://opensource.org/licenses/gpl-license.php GPL - GNU General Public License
* @package api
* @subpackage cache
* @author Ralf Becker <RalfBecker-AT-outdoor-training.de>
* @copyright (c) 2010-16 by Ralf Becker <RalfBecker-AT-outdoor-training.de>
* @version $Id$
*/
namespace EGroupware\Api\Cache;
/**
* Caching provider storing data in PHP's APCu extension / shared memory.
*
* The provider concats all $keys with '::' to get a single string.
*
* This provider is used by default, if it is available or explicit enabled in your header.inc.php:
* $GLOBALS['egw_info']['server']['cache_provider_instance'] = array('EGroupware\Api\Cache\Apc');
* and optional also $GLOBALS['egw_info']['server']['cache_provider_tree'] (defaults to instance)
*
* APC(u) and CLI:
* --------------
* APC(u) is not enabled by default for CLI (apc.enable_cli), nor would it access same shared memory!
* It makes no sense to fall back to files cache, as this is probably quite outdated,
* if PHP via Webserver uses APC. Better to use no cache at all.
* Api\Cache::get*() will return NULL for not found and Api\Cache::[un]set*()
* false for not being able to (un)set anything.
* It also does not make sense to report failure by throwing an Exception and filling
* up cron logs.
* --> if APC(u) is available for Webserver, we report availability for CLI too,
* but use no cache at all!
*/
class Apcu extends Base implements Provider
{
/**
* Constructor, eg. opens the connection to the backend
*
* @throws Exception if connection to backend could not be established
* @param array $params eg. array('localhost'[,'localhost:11211',...])
*/
function __construct(array $params)
{
if (!function_exists('apcu_fetch')) // apc >= 3.0
{
throw new Exception (__METHOD__.'('.array2string($params).") No function apcu_fetch()!");
}
}
/**
* Check if APC is available for caching user data
*
* Default shared memory size of 32M, which is used only for user data in APCu.
* Unlike APC which shares the total memory with it's opcode cache 32M is ok
* for a small install.
*
* @return boolean true: apc available, false: not
*/
public static function available()
{
if (($available = (bool)ini_get('apc.enabled') && function_exists('apcu_fetch')))
{
$size = ini_get('apc.shm_size');
switch(strtoupper(substr($size, -1)))
{
case 'G':
$size *= 1024;
case 'M':
$size *= 1024;
case 'K':
$size *= 1024;
}
$size *= ini_get('apc.shm_segments');
// only cache in APCu, if we have at least 32M available (default is 32M)
$available = $size >= 33554432;
}
//error_log(__METHOD__."() size=$size returning ".array2string($available));
return $available;
}
/**
* Stores some data in the cache, if it does NOT already exists there
*
* @param array $keys eg. array($level,$app,$location)
* @param mixed $data
* @param int $expiration =0
* @return boolean true on success, false on error, incl. key already exists in cache
*/
function add(array $keys,$data,$expiration=0)
{
return apcu_add(self::key($keys),$data,$expiration);
}
/**
* Stores some data in the cache
*
* @param array $keys eg. array($level,$app,$location)
* @param mixed $data
* @param int $expiration =0
* @return boolean true on success, false on error
*/
function set(array $keys,$data,$expiration=0)
{
return apcu_store(self::key($keys),$data,$expiration);
}
/**
* Get some data from the cache
*
* @param array $keys eg. array($level,$app,$location)
* @return mixed data stored or NULL if not found in cache
*/
function get(array $keys)
{
$success = null;
$data = apcu_fetch($key=self::key($keys),$success);
if (!$success)
{
//error_log(__METHOD__."(".array2string($keys).") key='$key' NOT found!");
return null;
}
//error_log(__METHOD__."(".array2string($keys).") key='$key' found ".bytes(serialize($data))." bytes).");
return $data;
}
/**
* Delete some data from the cache
*
* @param array $keys eg. array($level,$app,$location)
* @return boolean true on success, false on error (eg. $key not set)
*/
function delete(array $keys)
{
return apcu_delete(self::key($keys));
}
/**
* Delete all data under given keys
*
* @param array $keys eg. array($level,$app,$location)
* @return boolean true on success, false on error (eg. $key not set)
*/
function flush(array $keys)
{
// APCu > 5 has APCUIterator
if (class_exists('APCUIterator'))
{
$iterator = new \APCUIterator($preg='/^'.preg_quote(self::key($keys).'/'));
}
// APC >= 3.1.1, but also seems to be missing if apc is disabled eg. for cli
elseif(class_exists('APCIterator'))
{
$iterator = new \APCIterator('user', $preg='/^'.preg_quote(self::key($keys).'/'));
}
else
{
if (function_exists('apcu_clear_cache')) apcu_clear_cache ();
return false;
}
foreach($iterator as $item)
{
//error_log(__METHOD__."(".array2string($keys).") preg='$preg': calling apcu_delete('$item[key]')");
apcu_delete($item['key']);
}
return true;
}
/**
* Create a single key from $keys
*
* @param array $keys
* @return string
*/
private static function key(array $keys)
{
return implode('::',$keys);
}
}