/** determine if any of the ancestors or $node_id itself is already expired
*
* This climbs the tree upward, starting at $node_id, to see if any nodes
* are expired. If an expired node is detected, TRUE is returned.
* If none of the nodes are expired, then FALSE is returned.
*
* Note that this routine looks strictly at the expiry property, it is very
* well possible that a node is under embargo, see {@link is_under_embargo()}.
*
* Also note that this routine currently also tries to 'fix' the node database
* when a circular reference is detected. This doesn't really belong here, but
* for the time being it is convenient to have this auto-repair mechanism here.
* The node that is fixed is the section we are looking at after MAXIMUM_ITERATIONS
* tries, which is not necessarily the node we started with.
*
* @param int $node_id
* @param array &$tree family tree
* @return bool TRUE if any ancestor (or node_id) is expired, otherwise FALSE
* @todo this function also 'repairs' circular references. This should move to a separate
* tree-repair function but for the time being it is "convenient" to have automatic repairs...
* @uses $DB
*/
function is_expired($node_id, &$tree)
{
global $DB;
$tries = MAXIMUM_ITERATIONS;
$now = strftime('%Y-%m-%d %T');
$node_id = intval($node_id);
for ($next_id = $node_id; $next_id != 0 && --$tries > 0; $next_id = $tree[$next_id]['parent_id']) {
if ($tree[$next_id]['record']['expiry'] < $now) {
return TRUE;
}
}
if ($tries <= 0) {
// circular reference detected, try to fix it
// insert offending node before first node at the top level
// this becomes visible the _next_ time the tree is read from the database
$first_id = $tree[0]['first_child_id'];
$sort_order = $first_id != 0 ? intval($tree[$first_id]['record']['sort_order']) - 10 : 10;
$fields = array('parent_id' => $next_id, 'sort_order' => $sort_order);
$where = array('node_id' => $next_id);
$sql = db_update_sql('nodes', $fields, $where);
$parent_id = intval($tree[$node_id]['parent_id']);
logger("is_expired(): circular reference '{$node_id}' (parent '{$parent_id}') fixed with '{$sql}'", WLOG_DEBUG);
$DB->exec($sql);
}
return FALSE;
}
/** update one or more fields in a table
*
* @param string the name of the table to update (without prefix)
* @param array an associative array with fieldnames and fieldvalues
* @param mixed a single clause or an array with fieldnames => values ((without the WHERE keyword)
* @return bool|int FALSE on failure or the number of affected rows
* @uses db_update_sql()
*/
function db_update($tablename, $fields, $where = '')
{
global $DB;
return $DB->exec(db_update_sql($tablename, $fields, $where));
}
