wiki.techinc.nl/includes/objectcache/BagOStuff.php
2012-02-09 21:35:05 +00:00

169 lines
4 KiB
PHP

<?php
/**
* Classes to cache objects in PHP accelerators, SQL database or DBA files
*
* Copyright © 2003-2004 Brion Vibber <brion@pobox.com>
* http://www.mediawiki.org/
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
* @ingroup Cache
*/
/**
* @defgroup Cache Cache
*/
/**
* interface is intended to be more or less compatible with
* the PHP memcached client.
*
* backends for local hash array and SQL table included:
* <code>
* $bag = new HashBagOStuff();
* $bag = new SqlBagOStuff(); # connect to db first
* </code>
*
* @ingroup Cache
*/
abstract class BagOStuff {
private $debugMode = false;
/**
* @param $bool bool
*/
public function setDebug( $bool ) {
$this->debugMode = $bool;
}
/* *** THE GUTS OF THE OPERATION *** */
/* Override these with functional things in subclasses */
/**
* Get an item with the given key. Returns false if it does not exist.
* @param $key string
*
* @return bool|Object
*/
abstract public function get( $key );
/**
* Set an item.
* @param $key string
* @param $value mixed
* @param $exptime int Either an interval in seconds or a unix timestamp for expiry
*/
abstract public function set( $key, $value, $exptime = 0 );
/**
* Delete an item.
* @param $key string
* @param $time int Amount of time to delay the operation (mostly memcached-specific)
*/
abstract public function delete( $key, $time = 0 );
public function lock( $key, $timeout = 0 ) {
/* stub */
return true;
}
public function unlock( $key ) {
/* stub */
return true;
}
public function keys() {
/* stub */
return array();
}
/**
* Delete all objects expiring before a certain date.
* @param $date string The reference date in MW format
* @param $progressCallback callback|bool Optional, a function which will be called
* regularly during long-running operations with the percentage progress
* as the first parameter.
*
* @return bool on success, false if unimplemented
*/
public function deleteObjectsExpiringBefore( $date, $progressCallback = false ) {
// stub
return false;
}
/* *** Emulated functions *** */
public function add( $key, $value, $exptime = 0 ) {
if ( !$this->get( $key ) ) {
$this->set( $key, $value, $exptime );
return true;
}
}
public function replace( $key, $value, $exptime = 0 ) {
if ( $this->get( $key ) !== false ) {
$this->set( $key, $value, $exptime );
}
}
/**
* @param $key String: Key to increase
* @param $value Integer: Value to add to $key (Default 1)
* @return null if lock is not possible else $key value increased by $value
*/
public function incr( $key, $value = 1 ) {
if ( !$this->lock( $key ) ) {
return null;
}
$value = intval( $value );
if ( ( $n = $this->get( $key ) ) !== false ) {
$n += $value;
$this->set( $key, $n ); // exptime?
}
$this->unlock( $key );
return $n;
}
public function decr( $key, $value = 1 ) {
return $this->incr( $key, - $value );
}
public function debug( $text ) {
if ( $this->debugMode ) {
$class = get_class( $this );
wfDebug( "$class debug: $text\n" );
}
}
/**
* Convert an optionally relative time to an absolute time
* @return int
*/
protected function convertExpiry( $exptime ) {
if ( ( $exptime != 0 ) && ( $exptime < 86400 * 3650 /* 10 years */ ) ) {
return time() + $exptime;
} else {
return $exptime;
}
}
}