/**
  * Limit products collection
  *
  * @param Mage_Catalog_Model_Resource_Product_Collection $collection
  */
 public function limitProducts($collection)
 {
     $relevantWebsiteIds = $this->_role->getRelevantWebsiteIds();
     $websiteIds = array();
     $filters = $collection->getLimitationFilters();
     if (isset($filters['website_ids'])) {
         $websiteIds = (array) $filters['website_ids'];
     }
     if (isset($filters['store_id'])) {
         $websiteIds[] = Mage::app()->getStore($filters['store_id'])->getWebsiteId();
     }
     if (count($websiteIds)) {
         $collection->addWebsiteFilter(array_intersect($websiteIds, $relevantWebsiteIds));
     } else {
         $collection->addWebsiteFilter($relevantWebsiteIds);
     }
 }