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   1  <?php
   2  /**
   3   * Resource loader request result caching in the file system.
   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   * Resource loader request result caching in the file system.
  26   *
  27   * @ingroup Cache
  28   */
  29  class ResourceFileCache extends FileCacheBase {
  30      protected $mCacheWorthy;
  31  
  32      /* @todo configurable? */
  33      const MISS_THRESHOLD = 360; // 6/min * 60 min
  34  
  35      /**
  36       * Construct an ResourceFileCache from a context
  37       * @param ResourceLoaderContext $context
  38       * @return ResourceFileCache
  39       */
  40  	public static function newFromContext( ResourceLoaderContext $context ) {
  41          $cache = new self();
  42  
  43          if ( $context->getOnly() === 'styles' ) {
  44              $cache->mType = 'css';
  45          } else {
  46              $cache->mType = 'js';
  47          }
  48          $modules = array_unique( $context->getModules() ); // remove duplicates
  49          sort( $modules ); // normalize the order (permutation => combination)
  50          $cache->mKey = sha1( $context->getHash() . implode( '|', $modules ) );
  51          if ( count( $modules ) == 1 ) {
  52              $cache->mCacheWorthy = true; // won't take up much space
  53          }
  54  
  55          return $cache;
  56      }
  57  
  58      /**
  59       * Check if an RL request can be cached.
  60       * Caller is responsible for checking if any modules are private.
  61       * @param ResourceLoaderContext $context
  62       * @return bool
  63       */
  64  	public static function useFileCache( ResourceLoaderContext $context ) {
  65          global $wgUseFileCache, $wgDefaultSkin, $wgLanguageCode;
  66          if ( !$wgUseFileCache ) {
  67              return false;
  68          }
  69          // Get all query values
  70          $queryVals = $context->getRequest()->getValues();
  71          foreach ( $queryVals as $query => $val ) {
  72              if ( $query === 'modules' || $query === 'version' || $query === '*' ) {
  73                  continue; // note: &* added as IE fix
  74              } elseif ( $query === 'skin' && $val === $wgDefaultSkin ) {
  75                  continue;
  76              } elseif ( $query === 'lang' && $val === $wgLanguageCode ) {
  77                  continue;
  78              } elseif ( $query === 'only' && in_array( $val, array( 'styles', 'scripts' ) ) ) {
  79                  continue;
  80              } elseif ( $query === 'debug' && $val === 'false' ) {
  81                  continue;
  82              }
  83  
  84              return false;
  85          }
  86  
  87          return true; // cacheable
  88      }
  89  
  90      /**
  91       * Get the base file cache directory
  92       * @return string
  93       */
  94  	protected function cacheDirectory() {
  95          return $this->baseCacheDirectory() . '/resources';
  96      }
  97  
  98      /**
  99       * Item has many recent cache misses
 100       * @return bool
 101       */
 102  	public function isCacheWorthy() {
 103          if ( $this->mCacheWorthy === null ) {
 104              $this->mCacheWorthy = (
 105                  $this->isCached() || // even stale cache indicates it was cache worthy
 106                  $this->getMissesRecent() >= self::MISS_THRESHOLD // many misses
 107              );
 108          }
 109  
 110          return $this->mCacheWorthy;
 111      }
 112  }