Horde_Form::validate PHP Method

    function validate($vars = null, $canAutoFill = false)
    {
        if (is_null($vars)) {
            $vars = $this->_vars;
        }
        /* Get submitted status. */
        if ($this->isSubmitted() || $canAutoFill) {
            /* Form was submitted or can autofill; check for any variable
             * types' onSubmit(). */
            $this->onSubmit($vars);
            /* Recheck submitted status. */
            if (!$this->isSubmitted() && !$canAutoFill) {
                return false;
            }
        } else {
            /* Form has not been submitted; return false. */
            return false;
        }
        $message = '';
        $this->_autofilled = true;
        if ($this->_useFormToken) {
            try {
                $tokenSource = $GLOBALS['injector']->getInstance('Horde_Token');
                $passedToken = $vars->get($this->_name . '_formToken');
                if (!empty($passedToken) && !$tokenSource->verify($passedToken)) {
                    $this->_errors['_formToken'] = Horde_Form_Translation::t("This form has already been processed.");
                }
            } catch (Horde_Exception $e) {
            }
            if (!$GLOBALS['session']->get('horde', 'form_secrets/' . $passedToken)) {
                $this->_errors['_formSecret'] = Horde_Form_Translation::t("Required secret is invalid - potentially malicious request.");
            }
        }
        foreach ($this->getVariables() as $var) {
            $this->_autofilled = $var->_autofilled && $this->_autofilled;
            if (!$var->validate($vars, $message)) {
                $this->_errors[$var->getVarName()] = $message;
            }
        }
        if ($this->_autofilled) {
            unset($this->_errors['_formToken']);
        }
        foreach ($this->_hiddenVariables as $var) {
            if (!$var->validate($vars, $message)) {
                $this->_errors[$var->getVarName()] = $message;
            }
        }
        return $this->isValid();
    }

 public function validate(&$vars)
 {
     if (!Whups::hasPermission($this->_queue, 'queue', Horde_Perms::DELETE)) {
         $this->setError('yesno', _("Permission Denied."));
     }
     return parent::validate($vars);
 }