WordPress/WordPress

<?php
/**
 * Widget API: WP_Widget_Meta class
 *
 * @package WordPress
 * @subpackage Widgets
 * @since 4.4.0
 */

/**
 * Core class used to implement a Meta widget.
 *
 * Displays log in/out, RSS feed links, etc.
 *
 * @since 2.8.0
 *
 * @see WP_Widget
 */
class WP_Widget_Meta extends WP_Widget {

    /**
     * Sets up a new Meta widget instance.
     *
     * @since 2.8.0
     */
    public function __construct() {
        $widget_ops = array(
            'classname'                   => 'widget_meta',
            'description'                 => __( 'Login, RSS, &amp; WordPress.org links.' ),
            'customize_selective_refresh' => true,
            'show_instance_in_rest'       => true,
        );
        parent::__construct( 'meta', __( 'Meta' ), $widget_ops );
    }

    /**
     * Outputs the content for the current Meta widget instance.
     *
     * @since 2.8.0
     *
     * @param array $args     Display arguments including 'before_title', 'after_title',
     *                        'before_widget', and 'after_widget'.
     * @param array $instance Settings for the current Meta widget instance.
     */
    public function widget( $args, $instance ) {
        $default_title = __( 'Meta' );
        $title         = ! empty( $instance['title'] ) ? $instance['title'] : $default_title;

        /** This filter is documented in wp-includes/widgets/class-wp-widget-pages.php */
        $title = apply_filters( 'widget_title', $title, $instance, $this->id_base );

        echo $args['before_widget'];

        if ( $title ) {
            echo $args['before_title'] . $title . $args['after_title'];
        }

        $format = current_theme_supports( 'html5', 'navigation-widgets' ) ? 'html5' : 'xhtml';

        /** This filter is documented in wp-includes/widgets/class-wp-nav-menu-widget.php */
        $format = apply_filters( 'navigation_widgets_format', $format );

        if ( 'html5' === $format ) {
            // The title may be filtered: Strip out HTML and make sure the aria-label is never empty.
            $title      = trim( strip_tags( $title ) );
            $aria_label = $title ? $title : $default_title;
            echo '<nav aria-label="' . esc_attr( $aria_label ) . '">';
        }
        ?>

        <ul>
            <?php wp_register(); ?>
            <li><?php wp_loginout(); ?></li>
            <li><a href="<?php echo esc_url( get_bloginfo( 'rss2_url' ) ); ?>"><?php _e( 'Entries feed' ); ?></a></li>
            <li><a href="<?php echo esc_url( get_bloginfo( 'comments_rss2_url' ) ); ?>"><?php _e( 'Comments feed' ); ?></a></li>

            <?php
            /**
             * Filters the "WordPress.org" list item HTML in the Meta widget.
             *
             * @since 3.6.0
             * @since 4.9.0 Added the `$instance` parameter.
             *
             * @param string $html     Default HTML for the WordPress.org list item.
             * @param array  $instance Array of settings for the current widget.
             */
            echo apply_filters(
                'widget_meta_poweredby',
                sprintf(
                    '<li><a href="%1$s">%2$s</a></li>',
                    esc_url( __( 'https://wordpress.org/' ) ),
                    __( 'WordPress.org' )
                ),
                $instance
            );

            wp_meta();
            ?>

        </ul>

        <?php
        if ( 'html5' === $format ) {
            echo '</nav>';
        }

        echo $args['after_widget'];
    }

    /**
     * Handles updating settings for the current Meta widget instance.
     *
     * @since 2.8.0
     *
     * @param array $new_instance New settings for this instance as input by the user via
     *                            WP_Widget::form().
     * @param array $old_instance Old settings for this instance.
     * @return array Updated settings to save.
     */
    public function update( $new_instance, $old_instance ) {
        $instance          = $old_instance;
        $instance['title'] = sanitize_text_field( $new_instance['title'] );

        return $instance;
    }

    /**
     * Outputs the settings form for the Meta widget.
     *
     * @since 2.8.0
     *
     * @param array $instance Current settings.
     */
    public function form( $instance ) {
        $instance = wp_parse_args( (array) $instance, array( 'title' => '' ) );
        ?>
        <p>
            <label for="<?php echo $this->get_field_id( 'title' ); ?>"><?php _e( 'Title:' ); ?></label>
            <input class="widefat" id="<?php echo $this->get_field_id( 'title' ); ?>" name="<?php echo $this->get_field_name( 'title' ); ?>" type="text" value="<?php echo esc_attr( $instance['title'] ); ?>" />
        </p>
        <?php
    }
}