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