wp_theme_has_theme_json

wp_theme_has_theme_json： 这是一个WordPress的函数，用来检查活动主题是否有一个theme.json文件。这个文件用于定义主题的各种设置和配置，例如块样式和块支持。

function wp_theme_has_theme_json() {
	static $theme_has_support = null;

	if (
		null !== $theme_has_support &&
		/*
		 * Ignore static cache when `WP_DEBUG` is enabled. Why? To avoid interfering with
		 * the theme developer's workflow.
		 *
		 * @todo Replace `WP_DEBUG` once an "in development mode" check is available in Core.
		 */
		! WP_DEBUG &&
		/*
		 * Ignore cache when automated test suites are running. Why? To ensure
		 * the static cache is reset between each test.
		 */
		! ( defined( 'WP_RUN_CORE_TESTS' ) && WP_RUN_CORE_TESTS )
	) {
		return $theme_has_support;
	}

	// Does the theme have its own theme.json?
	$theme_has_support = is_readable( get_stylesheet_directory() . '/theme.json' );

	// Look up the parent if the child does not have a theme.json.
	if ( ! $theme_has_support ) {
		$theme_has_support = is_readable( get_template_directory() . '/theme.json' );
	}

	return $theme_has_support;
}