includes/site/CachingSiteStore.php

   1 <?php
   2
   3 /**
   4  * Represents the site configuration of a wiki.
   5  * Holds a list of sites (ie SiteList), with a caching layer.
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along
  18  * with this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  20  * http://www.gnu.org/copyleft/gpl.html
  21  *
  22  * @since 1.25
  23  *
  24  * @file
  25  * @ingroup Site
  26  *
  27  * @license GNU GPL v2+
  28  * @author Jeroen De Dauw < jeroendedauw@gmail.com >
  29  * @author Katie Filbert < aude.wiki@gmail.com >
  30  */
  31 class CachingSiteStore implements SiteStore {
  32
  33         /**
  34          * @var SiteList|null
  35          */
  36         private $sites = null;
  37
  38         /**
  39          * @var string|null
  40          */
  41         private $cacheKey;
  42
  43         /**
  44          * @var int
  45          */
  46         private $cacheTimeout;
  47
  48         /**
  49          * @var BagOStuff
  50          */
  51         private $cache;
  52
  53         /**
  54          * @var SiteStore
  55          */
  56         private $siteStore;
  57
  58         /**
  59          * @param SiteStore $siteStore
  60          * @param BagOStuff $cache
  61          * @param string|null $cacheKey
  62          * @param int $cacheTimeout
  63          */
  64         public function __construct(
  65                 SiteStore $siteStore,
  66                 BagOStuff $cache,
  67                 $cacheKey = null,
  68                 $cacheTimeout = 3600
  69         ) {
  70                 $this->siteStore = $siteStore;
  71                 $this->cache = $cache;
  72                 $this->cacheKey = $cacheKey;
  73                 $this->cacheTimeout = $cacheTimeout;
  74         }
  75
  76         /**
  77          * Constructs a cache key to use for caching the list of sites.
  78          *
  79          * This includes the concrete class name of the site list as well as a version identifier
  80          * for the list's serialization, to avoid problems when unserializing site lists serialized
  81          * by an older version, e.g. when reading from a cache.
  82          *
  83          * The cache key also includes information about where the sites were loaded from, e.g.
  84          * the name of a database table.
  85          *
  86          * @see SiteList::getSerialVersionId
  87          *
  88          * @return string The cache key.
  89          */
  90         private function getCacheKey() {
  91                 if ( $this->cacheKey === null ) {
  92                         $type = 'SiteList#' . SiteList::getSerialVersionId();
  93                         $this->cacheKey = wfMemcKey( "sites/$type" );
  94                 }
  95
  96                 return $this->cacheKey;
  97         }
  98
  99         /**
 100          * @see SiteStore::getSites
 101          *
 102          * @since 1.25
 103          *
 104          * @return SiteList
 105          */
 106         public function getSites() {
 107                 if ( $this->sites === null ) {
 108                         $this->sites = $this->cache->get( $this->getCacheKey() );
 109
 110                         if ( !is_object( $this->sites ) ) {
 111                                 $this->sites = $this->siteStore->getSites();
 112
 113                                 $this->cache->set( $this->getCacheKey(), $this->sites, $this->cacheTimeout );
 114                         }
 115                 }
 116
 117                 return $this->sites;
 118         }
 119
 120         /**
 121          * @see SiteStore::getSite
 122          *
 123          * @since 1.25
 124          *
 125          * @param string $globalId
 126          *
 127          * @return Site|null
 128          */
 129         public function getSite( $globalId ) {
 130                 $sites = $this->getSites();
 131
 132                 return $sites->hasSite( $globalId ) ? $sites->getSite( $globalId ) : null;
 133         }
 134
 135         /**
 136          * @see SiteStore::saveSite
 137          *
 138          * @since 1.25
 139          *
 140          * @param Site $site
 141          *
 142          * @return bool Success indicator
 143          */
 144         public function saveSite( Site $site ) {
 145                 return $this->saveSites( array( $site ) );
 146         }
 147
 148         /**
 149          * @see SiteStore::saveSites
 150          *
 151          * @since 1.25
 152          *
 153          * @param Site[] $sites
 154          *
 155          * @return bool Success indicator
 156          */
 157         public function saveSites( array $sites ) {
 158                 if ( empty( $sites ) ) {
 159                         return true;
 160                 }
 161
 162                 $success = $this->siteStore->saveSites( $sites );
 163
 164                 // purge cache
 165                 $this->reset();
 166
 167                 return $success;
 168         }
 169
 170         /**
 171          * Purges the internal and external cache of the site list, forcing the list.
 172          * of sites to be reloaded.
 173          *
 174          * Only use this for testing, as APC is typically used and is per-server
 175          *
 176          * @since 1.25
 177          */
 178         public function reset() {
 179                 // purge cache
 180                 $this->cache->delete( $this->getCacheKey() );
 181                 $this->sites = null;
 182         }
 183
 184         /**
 185          * Clears the list of sites stored.
 186          *
 187          * Only use this for testing, as APC is typically used and is per-server.
 188          *
 189          * @see SiteStore::clear()
 190          *
 191          * @return bool Success
 192          */
 193         public function clear() {
 194                 $this->reset();
 195
 196                 return $this->siteStore->clear();
 197         }
 198
 199 }