wiki.techinc.nl/includes/libs/objectcache/HashBagOStuff.php
Aaron Schulz 962495b17a objectcache: merge getWithToken() into doGet() for simplicity
Change-Id: I581f866521e1086ca350973d9cdeff6656f48fe8
2019-03-27 13:03:25 -07:00

154 lines
3.7 KiB
PHP

<?php
/**
* Per-process memory cache for storing items.
*
* 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
*/
/**
* Simple store for keeping values in an associative array for the current process.
*
* Data will not persist and is not shared with other processes.
*
* @ingroup Cache
*/
class HashBagOStuff extends BagOStuff {
/** @var mixed[] */
protected $bag = [];
/** @var int Max entries allowed */
protected $maxCacheKeys;
/** @var string CAS token prefix for this instance */
private $token;
/** @var int CAS token counter */
private static $casCounter = 0;
const KEY_VAL = 0;
const KEY_EXP = 1;
const KEY_CAS = 2;
/**
* @param array $params Additional parameters include:
* - maxKeys : only allow this many keys (using oldest-first eviction)
*/
function __construct( $params = [] ) {
parent::__construct( $params );
$this->token = microtime( true ) . ':' . mt_rand();
$this->maxCacheKeys = $params['maxKeys'] ?? INF;
if ( $this->maxCacheKeys <= 0 ) {
throw new InvalidArgumentException( '$maxKeys parameter must be above zero' );
}
}
protected function doGet( $key, $flags = 0, &$casToken = null ) {
$casToken = null;
if ( !$this->hasKey( $key ) || $this->expire( $key ) ) {
return false;
}
// Refresh key position for maxCacheKeys eviction
$temp = $this->bag[$key];
unset( $this->bag[$key] );
$this->bag[$key] = $temp;
$casToken = $this->bag[$key][self::KEY_CAS];
return $this->bag[$key][self::KEY_VAL];
}
public function set( $key, $value, $exptime = 0, $flags = 0 ) {
// Refresh key position for maxCacheKeys eviction
unset( $this->bag[$key] );
$this->bag[$key] = [
self::KEY_VAL => $value,
self::KEY_EXP => $this->convertToExpiry( $exptime ),
self::KEY_CAS => $this->token . ':' . ++self::$casCounter
];
if ( count( $this->bag ) > $this->maxCacheKeys ) {
reset( $this->bag );
$evictKey = key( $this->bag );
unset( $this->bag[$evictKey] );
}
return true;
}
public function add( $key, $value, $exptime = 0, $flags = 0 ) {
if ( $this->get( $key ) === false ) {
return $this->set( $key, $value, $exptime, $flags );
}
return false; // key already set
}
public function delete( $key, $flags = 0 ) {
unset( $this->bag[$key] );
return true;
}
public function incr( $key, $value = 1 ) {
$n = $this->get( $key );
if ( $this->isInteger( $n ) ) {
$n = max( $n + intval( $value ), 0 );
$this->bag[$key][self::KEY_VAL] = $n;
return $n;
}
return false;
}
/**
* Clear all values in cache
*/
public function clear() {
$this->bag = [];
}
/**
* @param string $key
* @return bool
*/
protected function expire( $key ) {
$et = $this->bag[$key][self::KEY_EXP];
if ( $et == self::TTL_INDEFINITE || $et > $this->getCurrentTime() ) {
return false;
}
$this->delete( $key );
return true;
}
/**
* Does this bag have a non-null value for the given key?
*
* @param string $key
* @return bool
* @since 1.27
*/
protected function hasKey( $key ) {
return isset( $this->bag[$key] );
}
}