1<?php
  2/**
  3 * Custom classname block support flag.
  4 *
  5 * @package WordPress
  6 * @since 5.6.0
  7 */
  8
  9/**
 10 * Registers the custom classname block attribute for block types that support it.
 11 *
 12 * @since 5.6.0
 13 * @access private
 14 *
 15 * @param WP_Block_Type $block_type Block Type.
 16 */
 17function wp_register_custom_classname_support( $block_type ) {
 18	$has_custom_classname_support = block_has_support( $block_type, 'customClassName', true );
 19
 20	if ( $has_custom_classname_support ) {
 21		if ( ! $block_type->attributes ) {
 22			$block_type->attributes = array();
 23		}
 24
 25		if ( ! array_key_exists( 'className', $block_type->attributes ) ) {
 26			$block_type->attributes['className'] = array(
 27				'type' => 'string',
 28			);
 29		}
 30	}
 31}
 32
 33/**
 34 * Adds the custom classnames to the output.
 35 *
 36 * @since 5.6.0
 37 * @access private
 38 *
 39 * @param  WP_Block_Type $block_type       Block Type.
 40 * @param  array         $block_attributes Block attributes.
 41 *
 42 * @return array Block CSS classes and inline styles.
 43 */
 44function wp_apply_custom_classname_support( $block_type, $block_attributes ) {
 45	$has_custom_classname_support = block_has_support( $block_type, 'customClassName', true );
 46	$attributes                   = array();
 47	if ( $has_custom_classname_support ) {
 48		$has_custom_classnames = array_key_exists( 'className', $block_attributes );
 49
 50		if ( $has_custom_classnames ) {
 51			$attributes['class'] = $block_attributes['className'];
 52		}
 53	}
 54
 55	return $attributes;
 56}
 57
 58// Register the block support.
 59WP_Block_Supports::get_instance()->register(
 60	'custom-classname',
 61	array(
 62		'register_attribute' => 'wp_register_custom_classname_support',
 63		'apply'              => 'wp_apply_custom_classname_support',
 64	)
 65);
 66