<?php
/**
 * Rule checking that the field is empty
 *
 * PHP version 5
 *
 * LICENSE:
 *
 * Copyright (c) 2006-2011, Alexey Borzov <avb@php.net>,
 *                          Bertrand Mansion <golgote@mamasam.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *    * Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *    * Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *    * The names of the authors may not be used to endorse or promote products
 *      derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * @category   HTML
 * @package    HTML_QuickForm2
 * @author     Alexey Borzov <avb@php.net>
 * @author     Bertrand Mansion <golgote@mamasam.com>
 * @license    http://opensource.org/licenses/bsd-license.php New BSD License
 * @version    SVN: $Id: Empty.php 311435 2011-05-26 10:30:06Z avb $
 * @link       http://pear.php.net/package/HTML_QuickForm2
 */

/**
 * Base class for HTML_QuickForm2 rules
 */
// -- // require_once 'HTML/QuickForm2/Rule.php';

/**
 * Rule checking that the field is empty
 *
 * Handles both simple form fields and file uploads, the latter are considered
 * valid iff no file upload was attempted.
 *
 * The rule doesn't make much sense if used separately, but can be very helpful
 * if chained:
 * <code>
 * $spamCheck->addRule('empty')
 *           ->or_($email->createRule('nonempty', 'Supply a valid email if you want to receive our spam')
 *                       ->and_($email->createRule('email')));
 * </code>
 *
 * @category   HTML
 * @package    HTML_QuickForm2
 * @author     Alexey Borzov <avb@php.net>
 * @author     Bertrand Mansion <golgote@mamasam.com>
 * @version    Release: @package_version@
 */
class HTML_QuickForm2_Rule_Empty extends HTML_QuickForm2_Rule
{
    protected function validateOwner()
    {
        $value = $this->owner->getValue();
        if ($this->owner instanceof HTML_QuickForm2_Element_InputFile) {
            return isset($value['error']) && UPLOAD_ERR_NO_FILE == $value['error'];
        } elseif (is_array($value)) {
            return 0 == count(array_filter($value, 'strlen'));
        } else {
            return 0 == strlen($value);
        }
    }

    protected function getJavascriptCallback()
    {
        return "function() { return qf.rules.empty(" . $this->owner->getJavascriptValue() . "); }";
    }
}