includes/libs/objectcache/WinCacheBagOStuff.php

   1 <?php
   2 /**
   3  * Object caching using WinCache.
   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  * Wrapper for WinCache object caching functions; identical interface
  26  * to the APC wrapper
  27  *
  28  * @ingroup Cache
  29  */
  30 class WinCacheBagOStuff extends MediumSpecificBagOStuff {
  31         public function __construct( array $params = [] ) {
  32                 $params['segmentationSize'] = $params['segmentationSize'] ?? INF;
  33                 parent::__construct( $params );
  34         }
  35
  36         protected function doGet( $key, $flags = 0, &$casToken = null ) {
  37                 $casToken = null;
  38
  39                 $blob = wincache_ucache_get( $key );
  40                 if ( !is_string( $blob ) && !is_int( $blob ) ) {
  41                         return false;
  42                 }
  43
  44                 $value = $this->unserialize( $blob );
  45                 if ( $value !== false ) {
  46                         $casToken = (string)$blob; // don't bother hashing this
  47                 }
  48
  49                 return $value;
  50         }
  51
  52         protected function doCas( $casToken, $key, $value, $exptime = 0, $flags = 0 ) {
  53                 if ( !wincache_lock( $key ) ) { // optimize with FIFO lock
  54                         return false;
  55                 }
  56
  57                 $curCasToken = null; // passed by reference
  58                 $this->doGet( $key, self::READ_LATEST, $curCasToken );
  59                 if ( $casToken === $curCasToken ) {
  60                         $success = $this->set( $key, $value, $exptime, $flags );
  61                 } else {
  62                         $this->logger->info(
  63                                 __METHOD__ . ' failed due to race condition for {key}.',
  64                                 [ 'key' => $key ]
  65                         );
  66
  67                         $success = false; // mismatched or failed
  68                 }
  69
  70                 wincache_unlock( $key );
  71
  72                 return $success;
  73         }
  74
  75         protected function doSet( $key, $value, $exptime = 0, $flags = 0 ) {
  76                 $result = wincache_ucache_set( $key, $this->serialize( $value ), $exptime );
  77
  78                 // false positive, wincache_ucache_set returns an empty array
  79                 // in some circumstances.
  80                 // @phan-suppress-next-line PhanTypeComparisonToArray
  81                 return ( $result === [] || $result === true );
  82         }
  83
  84         protected function doAdd( $key, $value, $exptime = 0, $flags = 0 ) {
  85                 if ( wincache_ucache_exists( $key ) ) {
  86                         return false; // avoid warnings
  87                 }
  88
  89                 $result = wincache_ucache_add( $key, $this->serialize( $value ), $exptime );
  90
  91                 // false positive, wincache_ucache_add returns an empty array
  92                 // in some circumstances.
  93                 // @phan-suppress-next-line PhanTypeComparisonToArray
  94                 return ( $result === [] || $result === true );
  95         }
  96
  97         protected function doDelete( $key, $flags = 0 ) {
  98                 wincache_ucache_delete( $key );
  99
 100                 return true;
 101         }
 102
 103         /**
 104          * Construct a cache key.
 105          *
 106          * @since 1.27
 107          * @param string $keyspace
 108          * @param array $args
 109          * @return string
 110          */
 111         public function makeKeyInternal( $keyspace, $args ) {
 112                 // WinCache keys have a maximum length of 150 characters. From that,
 113                 // subtract the number of characters we need for the keyspace and for
 114                 // the separator character needed for each argument. To handle some
 115                 // custom prefixes used by thing like WANObjectCache, limit to 125.
 116                 // NOTE: Same as in memcached, except the max key length there is 255.
 117                 $charsLeft = 125 - strlen( $keyspace ) - count( $args );
 118
 119                 $args = array_map(
 120                         function ( $arg ) use ( &$charsLeft ) {
 121                                 // 33 = 32 characters for the MD5 + 1 for the '#' prefix.
 122                                 if ( $charsLeft > 33 && strlen( $arg ) > $charsLeft ) {
 123                                         $arg = '#' . md5( $arg );
 124                                 }
 125
 126                                 $charsLeft -= strlen( $arg );
 127                                 return $arg;
 128                         },
 129                         $args
 130                 );
 131
 132                 if ( $charsLeft < 0 ) {
 133                         return $keyspace . ':BagOStuff-long-key:##' . md5( implode( ':', $args ) );
 134                 }
 135
 136                 return $keyspace . ':' . implode( ':', $args );
 137         }
 138
 139         /**
 140          * Increase stored value of $key by $value while preserving its original TTL
 141          * @param string $key Key to increase
 142          * @param int $value Value to add to $key (Default 1)
 143          * @return int|bool New value or false on failure
 144          */
 145         public function incr( $key, $value = 1 ) {
 146                 if ( !wincache_lock( $key ) ) { // optimize with FIFO lock
 147                         return false;
 148                 }
 149
 150                 $n = $this->doGet( $key );
 151                 if ( $this->isInteger( $n ) ) {
 152                         $n = max( $n + (int)$value, 0 );
 153                         $oldTTL = wincache_ucache_info( false, $key )["ucache_entries"][1]["ttl_seconds"];
 154                         $this->set( $key, $n, $oldTTL );
 155                 } else {
 156                         $n = false;
 157                 }
 158
 159                 wincache_unlock( $key );
 160
 161                 return $n;
 162         }
 163 }