includes/libs/objectcache/APCBagOStuff.php

   1 <?php
   2 /**
   3  * Object caching using PHP's APC accelerator.
   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
  24 /**
  25  * This is a wrapper for APC's shared memory functions
  26  *
  27  * @ingroup Cache
  28  */
  29 class APCBagOStuff extends BagOStuff {
  30
  31         /**
  32          * @var bool If true, trust the APC implementation to serialize and
  33          * deserialize objects correctly. If false, (de-)serialize in PHP.
  34          */
  35         protected $nativeSerialize;
  36
  37         /**
  38          * @var string String to append to each APC key. This may be changed
  39          *  whenever the handling of values is changed, to prevent existing code
  40          *  from encountering older values which it cannot handle.
  41          */
  42         const KEY_SUFFIX = ':2';
  43
  44         /**
  45          * Constructor
  46          *
  47          * Available parameters are:
  48          *   - nativeSerialize:     If true, pass objects to apc_store(), and trust it
  49          *                          to serialize them correctly. If false, serialize
  50          *                          all values in PHP.
  51          *
  52          * @param array $params
  53          */
  54         public function __construct( array $params = [] ) {
  55                 parent::__construct( $params );
  56
  57                 if ( isset( $params['nativeSerialize'] ) ) {
  58                         $this->nativeSerialize = $params['nativeSerialize'];
  59                 } elseif ( extension_loaded( 'apcu' ) && ini_get( 'apc.serializer' ) === 'default' ) {
  60                         // APCu has a memory corruption bug when the serializer is set to 'default'.
  61                         // See T120267, and upstream bug reports:
  62                         //  - https://github.com/krakjoe/apcu/issues/38
  63                         //  - https://github.com/krakjoe/apcu/issues/35
  64                         //  - https://github.com/krakjoe/apcu/issues/111
  65                         $this->logger->warning(
  66                                 'The APCu extension is loaded and the apc.serializer INI setting ' .
  67                                 'is set to "default". This can cause memory corruption! ' .
  68                                 'You should change apc.serializer to "php" instead. ' .
  69                                 'See <https://github.com/krakjoe/apcu/issues/38>.'
  70                         );
  71                         $this->nativeSerialize = false;
  72                 } else {
  73                         $this->nativeSerialize = true;
  74                 }
  75         }
  76
  77         protected function doGet( $key, $flags = 0 ) {
  78                 return $this->getUnserialize(
  79                         apc_fetch( $key . self::KEY_SUFFIX )
  80                 );
  81         }
  82
  83         protected function getUnserialize( $value ) {
  84                 if ( is_string( $value ) && !$this->nativeSerialize ) {
  85                         $value = $this->isInteger( $value )
  86                                 ? intval( $value )
  87                                 : unserialize( $value );
  88                 }
  89                 return $value;
  90         }
  91
  92         public function set( $key, $value, $exptime = 0, $flags = 0 ) {
  93                 apc_store(
  94                         $key . self::KEY_SUFFIX,
  95                         $this->setSerialize( $value ),
  96                         $exptime
  97                 );
  98
  99                 return true;
 100         }
 101
 102         protected function setSerialize( $value ) {
 103                 if ( !$this->nativeSerialize && !$this->isInteger( $value ) ) {
 104                         $value = serialize( $value );
 105                 }
 106                 return $value;
 107         }
 108
 109         public function delete( $key ) {
 110                 apc_delete( $key . self::KEY_SUFFIX );
 111
 112                 return true;
 113         }
 114
 115         public function incr( $key, $value = 1 ) {
 116                 return apc_inc( $key . self::KEY_SUFFIX, $value );
 117         }
 118
 119         public function decr( $key, $value = 1 ) {
 120                 return apc_dec( $key . self::KEY_SUFFIX, $value );
 121         }
 122 }