MemcacheCache.inc.php

<?php
 
import('lib.pkp.classes.cache.GenericCache');
 
// WARNING: This cache MUST be loaded in batch, or else many cache
// misses will result.
 
// Pseudotypes used to represent false and null values in the cache
class memcache_false {
}
class memcache_null {
}
 
class MemcacheCache extends GenericCache {
   var $connection;
 
   var $flag;
 
   var $expire;
 
   function __construct($context, $cacheId, $fallback, $hostname, $port) {
      parent::__construct($context, $cacheId, $fallback);
      $this->connection = new Memcached;
 
      // FIXME This should use connection pooling
      // XXX check whether memcached server is usable
      if (!$this->connection->addServer($hostname, $port)) {
         $this->connection = null;
      }
 
      $this->flag = null;
      $this->expire = 3600; // 1 hour default expiry
   }
 
   function setFlag($flag) {
      $this->flag = $flag;
   }
 
   function setExpiry($expiry) {
      $this->expire = $expiry;
   }
 
   function flush() {
      $this->connection->flush();
   }
 
   function getCache($id) {
      $result = $this->connection->get($this->getContext() . ':' . $this->getCacheId() . ':' . $id);
      if ($this->connection->getResultCode() == Memcached::RES_NOTFOUND) {
         return $this->cacheMiss;
      }
      switch (get_class($result)) {
         case 'memcache_false':
            $result = false;
         case 'memcache_null':
            $result = null;
      }
      return $result;
   }
 
   function setCache($id, $value) {
      if ($value === false) {
         $value = new memcache_false;
      } elseif ($value === null) {
         $value = new memcache_null;
      }
      return ($this->connection->set($this->getContext() . ':' . $this->getCacheId() . ':' . $id, $value, $this->expire));
   }
 
   function close() {
      $this->connection->quit();
      unset ($this->connection);
      $this->contextChecked = false;
   }
 
   function getCacheTime() {
      return null;
   }
 
   function setEntireCache($contents) {
      foreach ($contents as $id => $value) {
         $this->setCache($id, $value);
      }
   }
}