wp_autosave_post_revisioned_meta_fields( array $new_autosave )

2038function wp_autosave_post_revisioned_meta_fields( $new_autosave ) {2039	/*2040	 * The post data arrives as either $_POST['data']['wp_autosave'] or the $_POST2041	 * itself. This sets $posted_data to the correct variable.2042	 *2043	 * Ignoring sanitization to avoid altering meta. Ignoring the nonce check because2044	 * this is hooked on inner core hooks where a valid nonce was already checked.2045	 */2046	$posted_data = isset( $_POST['data']['wp_autosave'] ) ? $_POST['data']['wp_autosave'] : $_POST;2047 2048	$post_type = get_post_type( $new_autosave['post_parent'] );2049 2050	/*2051	 * Go through the revisioned meta keys and save them as part of the autosave,2052	 * if the meta key is part of the posted data, the meta value is not blank,2053	 * and the meta value has changes from the last autosaved value.2054	 */2055	foreach ( wp_post_revision_meta_keys( $post_type ) as $meta_key ) {2056 2057		if ( isset( $posted_data[ $meta_key ] )2058			&& get_post_meta( $new_autosave['ID'], $meta_key, true ) !== wp_unslash( $posted_data[ $meta_key ] )2059		) {2060			/*2061			 * Use the underlying delete_metadata() and add_metadata() functions2062			 * vs delete_post_meta() and add_post_meta() to make sure we're working2063			 * with the actual revision meta.2064			 */2065			delete_metadata( 'post', $new_autosave['ID'], $meta_key );2066 2067			// One last check to ensure meta value is not empty.2068			if ( ! empty( $posted_data[ $meta_key ] ) ) {2069				// Add the revisions meta data to the autosave.2070				add_metadata( 'post', $new_autosave['ID'], $meta_key, $posted_data[ $meta_key ] );2071			}2072		}2073	}2074}