wp_ajax_save_widget()

function wp_ajax_save_widget() {
	global $wp_registered_widgets, $wp_registered_widget_controls, $wp_registered_widget_updates;

	check_ajax_referer( 'save-sidebar-widgets', 'savewidgets' );

	if ( !current_user_can('edit_theme_options') || !isset($_POST['id_base']) )
		wp_die( -1 );

	unset( $_POST['savewidgets'], $_POST['action'] );

	/**
	 * Fires early when editing the widgets displayed in sidebars.
	 *
	 * @since WP-2.8.0
	 */
	do_action( 'load-widgets.php' );

	/**
	 * Fires early when editing the widgets displayed in sidebars.
	 *
	 * @since WP-2.8.0
	 */
	do_action( 'widgets.php' );

	/** This action is documented in wp-admin/widgets.php */
	do_action( 'sidebar_admin_setup' );

	$id_base = wp_unslash( $_POST['id_base'] );
	$widget_id = wp_unslash( $_POST['widget-id'] );
	$sidebar_id = $_POST['sidebar'];
	$multi_number = !empty($_POST['multi_number']) ? (int) $_POST['multi_number'] : 0;
	$settings = isset($_POST['widget-' . $id_base]) && is_array($_POST['widget-' . $id_base]) ? $_POST['widget-' . $id_base] : false;
	$error = '<p>' . __('An error has occurred. Please reload the page and try again.') . '</p>';

	$sidebars = wp_get_sidebars_widgets();
	$sidebar = isset($sidebars[$sidebar_id]) ? $sidebars[$sidebar_id] : array();

	// Delete.
	if ( isset($_POST['delete_widget']) && $_POST['delete_widget'] ) {

		if ( !isset($wp_registered_widgets[$widget_id]) )
			wp_die( $error );

		$sidebar = array_diff( $sidebar, array($widget_id) );
		$_POST = array('sidebar' => $sidebar_id, 'widget-' . $id_base => array(), 'the-widget-id' => $widget_id, 'delete_widget' => '1');

		/** This action is documented in wp-admin/widgets.php */
		do_action( 'delete_widget', $widget_id, $sidebar_id, $id_base );

	} elseif ( $settings && preg_match( '/__i__|%i%/', key($settings) ) ) {
		if ( !$multi_number )
			wp_die( $error );

		$_POST[ 'widget-' . $id_base ] = array( $multi_number => reset( $settings ) );
		$widget_id = $id_base . '-' . $multi_number;
		$sidebar[] = $widget_id;
	}
	$_POST['widget-id'] = $sidebar;

	foreach ( (array) $wp_registered_widget_updates as $name => $control ) {

		if ( $name == $id_base ) {
			if ( !is_callable( $control['callback'] ) )
				continue;

			ob_start();
				call_user_func_array( $control['callback'], $control['params'] );
			ob_end_clean();
			break;
		}
	}

	if ( isset($_POST['delete_widget']) && $_POST['delete_widget'] ) {
		$sidebars[$sidebar_id] = $sidebar;
		wp_set_sidebars_widgets($sidebars);
		echo "deleted:$widget_id";
		wp_die();
	}

	if ( !empty($_POST['add_new']) )
		wp_die();

	if ( $form = $wp_registered_widget_controls[$widget_id] )
		call_user_func_array( $form['callback'], $form['params'] );

	wp_die();
}