Implements hook_query_TAG_alter().
This is the hook_query_alter() for queries tagged with 'node_access'. It adds node access checks for the user account given by the 'account' meta-data (or global $user if not provided), for an operation given by the 'op' meta-data (or 'view' if not provided; other possible values are 'update' and 'delete').
function node_query_node_access_alter(QueryAlterableInterface $query) {
_node_query_node_access_alter($query, 'node');
}