Cache used webfonts

lib/compat/wordpress-6.0/class-wp-webfonts.php

@@ -19,6 +19,15 @@ class WP_Webfonts {
 	 */
 	private static $webfonts = array();
 
+	/**
+	 * An array of used webfonts.
+	 *
+	 * @static
+	 * @access private
+	 * @var array
+	 */
+	private static $used_webfonts = array();
+
 	/**
 	 * An array of registered providers.
 	 *
@@ -51,12 +60,77 @@ public function init() {
 			$this->stylesheet_handle = 'webfonts';
 			$hook                    = 'wp_enqueue_scripts';
 		}
+
+		add_action( 'save_post_wp_template', array( $this, 'save_used_webfonts_for_template' ), 10, 2 );
+
 		add_action( $hook, array( $this, 'generate_and_enqueue_styles' ) );
 
 		// Enqueue webfonts in the block editor.
 		add_action( 'admin_init', array( $this, 'generate_and_enqueue_editor_styles' ) );
 	}
 
+	public function save_used_webfonts_for_template( $post_id, $post ) {
+		$blocks = _flatten_blocks( parse_blocks( $post->post_content ) );
+
+		foreach ( $blocks as $block ) {
+			$this->register_used_font_family_from_block( $block );
+		}
+
+		$this->register_used_font_families_on_global_styles();
+
+		update_option( 'gutenberg_used_webfonts', self::$used_webfonts );
+	}
+
+	private function register_used_font_family( $setting ) {
+		if ( isset( $setting['typography'] ) && isset( $setting['typography']['fontFamily'] ) ) {
+			$font_family_custom = $setting['typography']['fontFamily'];
+
+			if ( strpos( $font_family_custom, 'var:preset|font-family|' ) !== false ) {
+				$index_to_splice  = strrpos( $font_family_custom, '|' ) + 1;
+				$font_family_slug = _wp_to_kebab_case( substr( $font_family_custom, $index_to_splice ) );
+
+				self::$used_webfonts[ $font_family_slug ] = 1;
+			}
+		}
+	}
+
+	public function register_used_font_families_on_global_styles() {
+		$global_styles = gutenberg_get_global_styles();
+
+		foreach ( $global_styles['blocks'] as $id => $global_block_setting ) {
+			$this->register_used_font_family( $global_block_setting );
+		}
+
+		// Register used webfonts from elements.
+		foreach ( $global_styles['elements'] as $id => $global_element_setting ) {
+			$this->register_used_font_family( $global_element_setting );
+		}
+
+		// Register used webfonts from global styles.
+		$this->register_used_font_family( $global_styles );
+	}
+
+	public function register_used_font_family_from_block( $block ) {
+		if ( isset( $block['attrs']['fontFamily'] ) ) {
+			self::$used_webfonts[ $block['attrs']['fontFamily'] ] = 1;
+		}
+	}
+
+	private function filter_unused_webfonts() {
+		$registered_webfonts = $this->get_fonts();
+		$used_webfonts       = get_option( 'gutenberg_used_webfonts', array() );
+
+		foreach ( $registered_webfonts as $id => $webfont ) {
+			$font_name = _wp_to_kebab_case( $webfont['font-family'] );
+
+			if ( ! isset( $used_webfonts[ $font_name ] ) ) {
+				unset( $registered_webfonts[ $id ] );
+			}
+		}
+
+		self::$webfonts = $registered_webfonts;
+	}
+
 	/**
 	 * Get the list of fonts.
 	 *
@@ -202,6 +276,8 @@ public function register_provider( $provider, $class ) {
 	 * Generate and enqueue webfonts styles.
 	 */
 	public function generate_and_enqueue_styles() {
+		$this->filter_unused_webfonts();
+
 		// Generate the styles.
 		$styles = $this->generate_styles();