register_core_block_style_handles

注册核心代码区块样式句柄。

虽然{@see}通常用于此目的，但其实现方式对于核心代码块样式来说效率不高。在这里注册这些样式句柄可以避免在其他函数中进行不必要的逻辑和文件系统查找。

function register_core_block_style_handles() {
	global $wp_version;

	if ( ! wp_should_load_separate_core_block_assets() ) {
		return;
	}

	$blocks_url   = includes_url( 'blocks/' );
	$suffix       = wp_scripts_get_suffix();
	$wp_styles    = wp_styles();
	$style_fields = array(
		'style'       => 'style',
		'editorStyle' => 'editor',
	);

	static $core_blocks_meta;
	if ( ! $core_blocks_meta ) {
		$core_blocks_meta = require BLOCKS_PATH . 'blocks-json.php';
	}

	$files          = false;
	$transient_name = 'wp_core_block_css_files';

	/*
	 * Ignore transient cache when the development mode is set to 'core'. Why? To avoid interfering with
	 * the core developer's workflow.
	 */
	$can_use_cached = ! wp_is_development_mode( 'core' );

	if ( $can_use_cached ) {
		$cached_files = get_transient( $transient_name );

		// Check the validity of cached values by checking against the current WordPress version.
		if (
			is_array( $cached_files )
			&& isset( $cached_files['version'] )
			&& $cached_files['version'] === $wp_version
			&& isset( $cached_files['files'] )
		) {
			$files = $cached_files['files'];
		}
	}

	if ( ! $files ) {
		$files = glob( wp_normalize_path( BLOCKS_PATH . '**/**.css' ) );

		// Normalize BLOCKS_PATH prior to substitution for Windows environments.
		$normalized_blocks_path = wp_normalize_path( BLOCKS_PATH );

		$files = array_map(
			static function ( $file ) use ( $normalized_blocks_path ) {
				return str_replace( $normalized_blocks_path, '', $file );
			},
			$files
		);

		// Save core block style paths in cache when not in development mode.
		if ( $can_use_cached ) {
			set_transient(
				$transient_name,
				array(
					'version' => $wp_version,
					'files'   => $files,
				)
			);
		}
	}

	$register_style = static function ( $name, $filename, $style_handle ) use ( $blocks_url, $suffix, $wp_styles, $files ) {
		$style_path = "{$name}/{$filename}{$suffix}.css";
		$path       = wp_normalize_path( BLOCKS_PATH . $style_path );

		if ( ! in_array( $style_path, $files, true ) ) {
			$wp_styles->add(
				$style_handle,
				false
			);
			return;
		}

		$wp_styles->add( $style_handle, $blocks_url . $style_path );
		$wp_styles->add_data( $style_handle, 'path', $path );

		$rtl_file = "{$name}/{$filename}-rtl{$suffix}.css";
		if ( is_rtl() && in_array( $rtl_file, $files, true ) ) {
			$wp_styles->add_data( $style_handle, 'rtl', 'replace' );
			$wp_styles->add_data( $style_handle, 'suffix', $suffix );
			$wp_styles->add_data( $style_handle, 'path', str_replace( "{$suffix}.css", "-rtl{$suffix}.css", $path ) );
		}
	};

	foreach ( $core_blocks_meta as $name => $schema ) {
		/** This filter is documented in wp-includes/blocks.php */
		$schema = apply_filters( 'block_type_metadata', $schema );

		// Backfill these properties similar to `register_block_type_from_metadata()`.
		if ( ! isset( $schema['style'] ) ) {
			$schema['style'] = "wp-block-{$name}";
		}
		if ( ! isset( $schema['editorStyle'] ) ) {
			$schema['editorStyle'] = "wp-block-{$name}-editor";
		}

		// Register block theme styles.
		$register_style( $name, 'theme', "wp-block-{$name}-theme" );

		foreach ( $style_fields as $style_field => $filename ) {
			$style_handle = $schema[ $style_field ];
			if ( is_array( $style_handle ) ) {
				continue;
			}
			$register_style( $name, $filename, $style_handle );
		}
	}
}