Password.php

<?php

namespace Drupal\Core\Render\Element;

use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Render\Element;

/**
 * Provides a form element for entering a password, with hidden text.
 *
 * Properties:
 * - #size: The size of the input element in characters.
 * - #pattern: A string for the native HTML5 pattern attribute.
 *
 * Usage example:
 * @code
 * $form['pass'] = array(
 *   '#type' => 'password',
 *   '#title' => $this->t('Password'),
 *   '#size' => 25,
 *   '#pattern' => '[01]+',
 * );
 * @endcode
 *
 * @see \Drupal\Core\Render\Element\PasswordConfirm
 * @see \Drupal\Core\Render\Element\Textfield
 *
 * @FormElement("password")
 */
class Password extends FormElement {
    
    /**
     * {@inheritdoc}
     */
    public function getInfo() {
        $class = get_class($this);
        return [
            '#input' => TRUE,
            '#size' => 60,
            '#maxlength' => 128,
            '#process' => [
                [
                    $class,
                    'processAjaxForm',
                ],
                [
                    $class,
                    'processPattern',
                ],
            ],
            '#pre_render' => [
                [
                    $class,
                    'preRenderPassword',
                ],
            ],
            '#theme' => 'input__password',
            '#theme_wrappers' => [
                'form_element',
            ],
        ];
    }
    
    /**
     * Prepares a #type 'password' render element for input.html.twig.
     *
     * @param array $element
     *   An associative array containing the properties of the element.
     *   Properties used: #title, #value, #description, #size, #maxlength,
     *   #placeholder, #required, #attributes.
     *
     * @return array
     *   The $element with prepared variables ready for input.html.twig.
     */
    public static function preRenderPassword($element) {
        $element['#attributes']['type'] = 'password';
        Element::setAttributes($element, [
            'id',
            'name',
            'size',
            'maxlength',
            'placeholder',
        ]);
        static::setAttributes($element, [
            'form-text',
        ]);
        return $element;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function valueCallback(&$element, $input, FormStateInterface $form_state) {
        if ($input !== FALSE && $input !== NULL) {
            // This should be a string, but allow other scalars since they might be
            // valid input in programmatic form submissions.
            return is_scalar($input) ? (string) $input : '';
        }
        return NULL;
    }

}