Elgg\Database::fingerprintCallback PHP Метод

fingerprintCallback() публичный Метод

This is used to cache queries whose results were transformed by the callback. If the callback involves object method calls of the same class, different instances will return different values.
С версии: 1.9.4
public fingerprintCallback ( callable $callback ) : string
$callback callable The callable value to fingerprint
Результат string A string that is unique for each callable passed in
    public function fingerprintCallback($callback)
    {
        if (is_string($callback)) {
            return $callback;
        }
        if (is_object($callback)) {
            return spl_object_hash($callback) . "::__invoke";
        }
        if (is_array($callback)) {
            if (is_string($callback[0])) {
                return "{$callback[0]}::{$callback[1]}";
            }
            return spl_object_hash($callback[0]) . "::{$callback[1]}";
        }
        // this should not happen
        return "";
    }