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<?php/**
 * Custom classname block support flag.
 *
 * @package WordPress
 * @since 5.6.0
 */
 
 /**
 * Registers the custom classname block attribute for block types that support it.
 *
 * @since 5.6.0
 * @access private
 *
 * @param WP_Block_Type $block_type Block Type.
 */
 function wp_register_custom_classname_support( $block_type ) {
 $has_custom_classname_support = block_has_support( $block_type, 'customClassName', true );
 
 if ( $has_custom_classname_support ) {
 if ( ! $block_type->attributes ) {
 $block_type->attributes = array();
 }
 
 if ( ! array_key_exists( 'className', $block_type->attributes ) ) {
 $block_type->attributes['className'] = array(
 'type' => 'string',
 );
 }
 }
 }
 
 /**
 * Adds the custom classnames to the output.
 *
 * @since 5.6.0
 * @access private
 *
 * @param  WP_Block_Type $block_type       Block Type.
 * @param  array         $block_attributes Block attributes.
 *
 * @return array Block CSS classes and inline styles.
 */
 function wp_apply_custom_classname_support( $block_type, $block_attributes ) {
 $has_custom_classname_support = block_has_support( $block_type, 'customClassName', true );
 $attributes                   = array();
 if ( $has_custom_classname_support ) {
 $has_custom_classnames = array_key_exists( 'className', $block_attributes );
 
 if ( $has_custom_classnames ) {
 $attributes['class'] = $block_attributes['className'];
 }
 }
 
 return $attributes;
 }
 
 // Register the block support.
 WP_Block_Supports::get_instance()->register(
 'custom-classname',
 array(
 'register_attribute' => 'wp_register_custom_classname_support',
 'apply'              => 'wp_apply_custom_classname_support',
 )
 );
 
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