includes/libs/objectcache/HashBagOStuff.php

   1 <?php
   2 /**
   3  * Object caching using PHP arrays.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Cache
  22  */
  23 use Wikimedia\Assert\Assert;
  24
  25 /**
  26  * This is a test of the interface, mainly. It stores things in an associative
  27  * array, which is not going to persist between program runs.
  28  *
  29  * @ingroup Cache
  30  */
  31 class HashBagOStuff extends BagOStuff {
  32         /** @var mixed[] */
  33         protected $bag = array();
  34         /** @var integer Max entries allowed */
  35         protected $maxCacheKeys;
  36
  37         const KEY_VAL = 0;
  38         const KEY_EXP = 1;
  39
  40         /**
  41          * @param array $params Additional parameters include:
  42          *   - maxKeys : only allow this many keys (using oldest-first eviction)
  43          */
  44         function __construct( $params = array() ) {
  45                 parent::__construct( $params );
  46
  47                 $this->maxCacheKeys = isset( $params['maxKeys'] ) ? $params['maxKeys'] : INF;
  48                 Assert::parameter( $this->maxCacheKeys > 0, 'maxKeys', 'must be above zero' );
  49         }
  50
  51         protected function expire( $key ) {
  52                 $et = $this->bag[$key][self::KEY_EXP];
  53                 if ( $et == 0 || $et > time() ) {
  54                         return false;
  55                 }
  56
  57                 $this->delete( $key );
  58
  59                 return true;
  60         }
  61
  62         protected function doGet( $key, $flags = 0 ) {
  63                 if ( !isset( $this->bag[$key] ) ) {
  64                         return false;
  65                 }
  66
  67                 if ( $this->expire( $key ) ) {
  68                         return false;
  69                 }
  70
  71                 return $this->bag[$key][self::KEY_VAL];
  72         }
  73
  74         public function set( $key, $value, $exptime = 0, $flags = 0 ) {
  75                 $this->bag[$key] = array(
  76                         self::KEY_VAL => $value,
  77                         self::KEY_EXP => $this->convertExpiry( $exptime )
  78                 );
  79
  80                 if ( count( $this->bag ) > $this->maxCacheKeys ) {
  81                         reset( $this->bag );
  82                         $evictKey = key( $this->bag );
  83                         unset( $this->bag[$evictKey] );
  84                 }
  85
  86                 return true;
  87         }
  88
  89         public function delete( $key ) {
  90                 unset( $this->bag[$key] );
  91
  92                 return true;
  93         }
  94 }