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 BagOStuff {
  31         protected function doGet( $key, $flags = 0 ) {
  32                 $blob = wincache_ucache_get( $key );
  33
  34                 return is_string( $blob ) ? unserialize( $blob ) : false;
  35         }
  36
  37         protected function getWithToken( $key, &$casToken, $flags = 0 ) {
  38                 $casToken = null;
  39
  40                 $blob = wincache_ucache_get( $key );
  41                 if ( !is_string( $blob ) ) {
  42                         return false;
  43                 }
  44
  45                 $value = unserialize( $blob );
  46                 if ( $value === false ) {
  47                         return false;
  48                 }
  49
  50                 $casToken = $blob; // don't bother hashing this
  51
  52                 return $value;
  53         }
  54
  55         protected function cas( $casToken, $key, $value, $exptime = 0, $flags = 0 ) {
  56                 if ( !wincache_lock( $key ) ) { // optimize with FIFO lock
  57                         return false;
  58                 }
  59
  60                 $curCasToken = null; // passed by reference
  61                 $this->getWithToken( $key, $curCasToken, self::READ_LATEST );
  62                 if ( $casToken === $curCasToken ) {
  63                         $success = $this->set( $key, $value, $exptime, $flags );
  64                 } else {
  65                         $this->logger->info(
  66                                 __METHOD__ . ' failed due to race condition for {key}.',
  67                                 [ 'key' => $key ]
  68                         );
  69
  70                         $success = false; // mismatched or failed
  71                 }
  72
  73                 wincache_unlock( $key );
  74
  75                 return $success;
  76         }
  77
  78         public function set( $key, $value, $expire = 0, $flags = 0 ) {
  79                 $result = wincache_ucache_set( $key, serialize( $value ), $expire );
  80
  81                 return ( $result === [] || $result === true );
  82         }
  83
  84         public function add( $key, $value, $exptime = 0, $flags = 0 ) {
  85                 $result = wincache_ucache_add( $key, serialize( $value ), $exptime );
  86
  87                 return ( $result === [] || $result === true );
  88         }
  89
  90         public function delete( $key, $flags = 0 ) {
  91                 wincache_ucache_delete( $key );
  92
  93                 return true;
  94         }
  95
  96         public function merge( $key, callable $callback, $exptime = 0, $attempts = 10, $flags = 0 ) {
  97                 return $this->mergeViaCas( $key, $callback, $exptime, $attempts, $flags );
  98         }
  99
 100         /**
 101          * Construct a cache key.
 102          *
 103          * @since 1.27
 104          * @param string $keyspace
 105          * @param array $args
 106          * @return string
 107          */
 108         public function makeKeyInternal( $keyspace, $args ) {
 109                 // WinCache keys have a maximum length of 150 characters. From that,
 110                 // subtract the number of characters we need for the keyspace and for
 111                 // the separator character needed for each argument. To handle some
 112                 // custom prefixes used by thing like WANObjectCache, limit to 125.
 113                 // NOTE: Same as in memcached, except the max key length there is 255.
 114                 $charsLeft = 125 - strlen( $keyspace ) - count( $args );
 115
 116                 $args = array_map(
 117                         function ( $arg ) use ( &$charsLeft ) {
 118                                 // 33 = 32 characters for the MD5 + 1 for the '#' prefix.
 119                                 if ( $charsLeft > 33 && strlen( $arg ) > $charsLeft ) {
 120                                         $arg = '#' . md5( $arg );
 121                                 }
 122
 123                                 $charsLeft -= strlen( $arg );
 124                                 return $arg;
 125                         },
 126                         $args
 127                 );
 128
 129                 if ( $charsLeft < 0 ) {
 130                         return $keyspace . ':BagOStuff-long-key:##' . md5( implode( ':', $args ) );
 131                 }
 132
 133                 return $keyspace . ':' . implode( ':', $args );
 134         }
 135
 136         /**
 137          * Increase stored value of $key by $value while preserving its original TTL
 138          * @param string $key Key to increase
 139          * @param int $value Value to add to $key (Default 1)
 140          * @return int|bool New value or false on failure
 141          */
 142         public function incr( $key, $value = 1 ) {
 143                 if ( !wincache_lock( $key ) ) { // optimize with FIFO lock
 144                         return false;
 145                 }
 146
 147                 $n = $this->doGet( $key );
 148                 if ( $this->isInteger( $n ) ) {
 149                         $n = max( $n + (int)$value, 0 );
 150                         $oldTTL = wincache_ucache_info( false, $key )["ucache_entries"][1]["ttl_seconds"];
 151                         $this->set( $key, $n, $oldTTL );
 152                 } else {
 153                         $n = false;
 154                 }
 155
 156                 wincache_unlock( $key );
 157
 158                 return $n;
 159         }
 160 }