<?php
/**
 * $Id$
 *
 * @file
 * MongoDB engine class.
 */

class mongodbCacheRouterEngine extends CacheRouterEngine {
  var $collection;

  function page_fast_cache() {
    return $this->fast_cache;
  }

  function __construct($bin, $options, $default_options) {
    parent::__construct($bin, $options, $default_options);

    // Include required files.
    // This probably has to be moved to the parent class so it works
    // for all engines.
    if (!isset($options['include'])) {
      $options['include'] = $default_options['include'];
    }
    if (is_array($options['include'])) {
      foreach($options['include'] as $file) {
        include_once($file);
      }
    }
    else {
      include_once($options['include']);
    }

    $collection_name = $this->prefix . '-' . $bin;
    $this->collection = mongodb_collection($collection_name);
  }

  function get($key) {
    // Attempt to pull from static cache.
    $cache = parent::get($key);
    if (isset($cache)) {
      return $cache;
    }

    $cache = $this->collection->findOne(array('_id' => (string)$key));

    if (!$cache || !isset($cache['data'])) {
      return FALSE;
    }

    // Prepare cache object
    unset($cache['_id']);
    $cache = (object)$cache;
    if ($cache->serialized) {
      $cache->data = unserialize($cache->data);
    }

    // Update static cache
    parent::set($key, $cache);

    return $cache;
  }

  function garbage_collection() {
    global $user;

    // Garbage collection necessary when enforcing a minimum cache lifetime.
    $cache_flush = variable_get('cache_flush_' . $this->name, 0);
    if ($cache_flush && ($cache_flush + variable_get('cache_lifetime', 0) <= $_SERVER['REQUEST_TIME'])) {
      // Reset the variable immediately to prevent a meltdown in heavy load situations.
      variable_set('cache_flush_' . $this->name, 0);
      // Time to flush old cache data
      $find = array('expire' => array('$lte' => $cache_flush, '$ne' => CACHE_PERMANENT));
      $this->collection->remove($find);
    }
  }

  function set($key, $data, $expire = CACHE_PERMANENT, $headers = NULL) {
    $scalar = is_scalar($data);

    $entry = array(
      '_id' => (string)$key,
      'cid' => (string)$key,
      'created' => $_SERVER['REQUEST_TIME'],
      'expire' => $expire,
      'headers' => $headers,
      'serialized' => !$scalar,
      'data' => $scalar ? $data : serialize($data),
    );

    if (!empty($key)) {
      $this->collection->save($entry);
    }
  }

  function delete($key) {
    // Delete from static cache
    parent::flush();

    if ($key == '*') {
      // Whole bin delete
      $this->collection->remove();
    }
    elseif (substr($key, strlen($key) - 1, 1) == '*') {
      // Wildcard delete
      $cid = substr($key, 0, strlen($key) - 1);
      $this->collection->remove(array('cid' => new MongoRegex('/'. preg_quote($cid) .'.*/')));
    }
    else {
      // Single entry delete
      $this->collection->remove(array('_id' => (string)$key));
    }
  }

  function flush() {
    $this->collection->remove(array('expire' => array('$ne' => CACHE_PERMANENT, '$lte' => $_SERVER['REQUEST_TIME'])));
  }
}