Deprecate and make Fonts API non-functional.

lib/experimental/fonts/bc-layer/class-gutenberg-fonts-api-bc-layer.php

@@ -0,0 +1,49 @@
+<?php
+/**
+ * Fonts API BC Layer helpers.
+ *
+ * BACKPORT NOTE: Do not backport this file to Core.
+ * This file is now part of the API's Backwards-Compatibility (BC) layer.
+ *
+ * @package    Gutenberg
+ * @subpackage Fonts API
+ * @since      15.7.0
+ */
+
+/**
+ * Class Gutenberg_Fonts_API_BC_Layer
+ *
+ * BACKPORT NOTE: Do not backport this file to Core.
+ *
+ * @since X.X.X
+ * @deprecated 16.3.0 Fonts API is not supported.
+ */
+class Gutenberg_Fonts_API_BC_Layer {
+
+	/**
+	 * Determines if the given fonts array is the deprecated array structure.
+	 *
+	 * @since X.X.X
+	 * @deprecated 16.3.0 Structure check is not functional.
+	 *
+	 * @return bool False.
+	 */
+	public static function is_deprecated_structure() {
+		_deprecated_function( __METHOD__, 'Gutenberg 16.3.0' );
+		return false;
+	}
+
+	/**
+	 * Migrates deprecated fonts structure into new API data structure,
+	 * i.e. variations grouped by their font-family.
+	 *
+	 * @since X.X.X
+	 * @deprecated 16.3.0 Migrate is not supported.
+	 *
+	 * @return array Empty array.
+	 */
+	public static function migrate_deprecated_structure() {
+		_deprecated_function( __METHOD__, 'Gutenberg 16.3.0' );
+		return array();
+	}
+}

lib/experimental/fonts/bc-layer/class-wp-fonts-provider-local.php

@@ -0,0 +1,46 @@
+<?php
+/**
+ * Webfonts API: Provider for locally-hosted fonts.
+ *
+ * @package    WordPress
+ * @subpackage Fonts API
+ * @since      X.X.X
+ */
+
+if ( class_exists( 'WP_Fonts_Provider_Local' ) ) {
+	return;
+}
+
+/**
+ * A core bundled provider for generating `@font-face` styles
+ * from locally-hosted font files.
+ *
+ * @since X.X.X
+ * @deprecated 16.3.0 Providers are not supported.
+ *                    Local provider is in WP_Font_Face.
+ */
+class WP_Fonts_Provider_Local extends WP_Fonts_Provider {
+
+	/**
+	 * The provider's unique ID.
+	 *
+	 * @since X.X.X
+	 * @deprecated 16.3.0
+	 *
+	 * @var string
+	 */
+	protected $id = 'local';
+
+	/**
+	 * Gets the `@font-face` CSS styles for locally-hosted font files.
+	 *
+	 * @since X.X.X
+	 * @deprecated 16.3.0 Get styles is not supported.
+	 *
+	 * @return string Empty string.
+	 */
+	public function get_css() {
+		_deprecated_function( __FUNCTION__, 'Gutenberg 16.3' );
+		return '';
+	}
+}

lib/experimental/fonts/bc-layer/class-wp-fonts-provider.php

@@ -0,0 +1,98 @@
+<?php
+/**
+ * Fonts API: Provider abstract class.
+ *
+ * Individual fonts providers should extend this class and implement.
+ *
+ * @package    WordPress
+ * @subpackage Fonts API
+ * @since      X.X.X
+ */
+
+if ( class_exists( 'WP_Fonts_Provider' ) ) {
+	return;
+}
+
+/**
+ * Abstract class for Fonts API providers.
+ *
+ * @since X.X.X
+ * @deprecated 16.3.0 Custom providers are not supported.
+ */
+abstract class WP_Fonts_Provider {
+
+	/**
+	 * The provider's unique ID.
+	 *
+	 * @since X.X.X
+	 * @deprecated 16.3.0
+	 *
+	 * @var string
+	 */
+	protected $id = '';
+
+	/**
+	 * Fonts to be processed.
+	 *
+	 * @since X.X.X
+	 * @deprecated 16.3.0
+	 *
+	 * @var array[]
+	 */
+	protected $fonts = array();
+
+	/**
+	 * Array of Font-face style tag's attribute(s)
+	 * where the key is the attribute name and the
+	 * value is its value.
+	 *
+	 * @since X.X.X
+	 * @deprecated 16.3.0
+	 *
+	 * @var string[]
+	 */
+	protected $style_tag_atts = array();
+
+	/**
+	 * Sets this provider's fonts property.
+	 *
+	 * @since X.X.X
+	 * @deprecated 16.3.0 Set is not supported.
+	 */
+	public function set_fonts() {
+		_deprecated_function( __METHOD__, 'Gutenberg 16.3.0' );
+	}
+
+	/**
+	 * Prints the generated styles.
+	 *
+	 * @since X.X.X
+	 * @deprecated 16.3.0 Use wp_print_font_faces() instead.
+	 */
+	public function print_styles() {
+		_deprecated_function( __METHOD__, 'Gutenberg 16.3.0', 'wp_print_font_faces' );
+	}
+
+	/**
+	 * Gets the `@font-face` CSS for the provider's fonts.
+	 *
+	 * @since X.X.X
+	 * @deprecated 16.3.0
+	 *
+	 * @return string The `@font-face` CSS.
+	 */
+	abstract public function get_css();
+
+	/**
+	 * Gets the `<style>` element for wrapping the `@font-face` CSS.
+	 *
+	 * @since X.X.X
+	 * @deprecated 16.3.0 Get style element is not supported.
+	 *
+	 * @return string Empty string.
+	 */
+	protected function get_style_element() {
+		_deprecated_function( __METHOD__, 'Gutenberg 16.3.0' );
+		return '';
+	}
+}

lib/experimental/fonts/bc-layer/class-wp-fonts-resolver.php

@@ -0,0 +1,64 @@
+<?php
+/**
+ * WP_Fonts_Resolver class.
+ *
+ * @package    WordPress
+ * @subpackage Fonts API
+ * @since      X.X.X
+ */
+
+if ( class_exists( 'WP_Fonts_Resolver' ) ) {
+	return;
+}
+
+/**
+ * The Fonts API Resolver abstracts the processing of different data sources
+ * (such as theme.json and global styles) for font interactions with the API.
+ *
+ * This class is for internal core usage and is not supposed to be used by
+ * extenders (plugins and/or themes).
+ *
+ * @access private
+ *
+ * @since X.X.X
+ * @deprecated 16.3.0 Fonts API is not supported.
+ */
+class WP_Fonts_Resolver {
+
+	/**
+	 * Enqueues user-selected fonts via global styles.
+	 *
+	 * @since X.X.X
+	 * @deprecated 16.3.0 Enqueue is not supported.
+	 *
+	 * @return array Empty array.
+	 */
+	public static function enqueue_user_selected_fonts() {
+		_deprecated_function( __FUNCTION__, 'Gutenberg 16.3' );
+		return array();
+	}
+
+	/**
+	 * Register fonts defined in theme.json.
+	 *
+	 * @since X.X.X
+	 * @deprecated 16.3.0 Register is not supported.
+	 */
+	public static function register_fonts_from_theme_json() {
+		_deprecated_function( __FUNCTION__, 'Gutenberg 16.3' );
+	}
+
+	/**
+	 * Add missing fonts to the global styles.
+	 *
+	 * @since X.X.X
+	 * @deprecated 16.3.0 Adding fonts into theme.json theme data layer is not supported.
+	 *
+	 * @param WP_Theme_JSON_Gutenberg|WP_Theme_JSON $data The global styles.
+	 * @return WP_Theme_JSON_Gutenberg|WP_Theme_JSON Unchanged global styles.
+	 */
+	public static function add_missing_fonts_to_theme_json( $data ) {
+		_deprecated_function( __FUNCTION__, 'Gutenberg 16.3' );
+		return $data;
+	}
+}

lib/experimental/fonts/bc-layer/class-wp-fonts-utils.php

@@ -0,0 +1,74 @@
+<?php
+/**
+ * Font API's utility helpers.
+ *
+ * @package    WordPress
+ * @subpackage Fonts API
+ * @since      X.X.X
+ */
+
+if ( class_exists( 'WP_Fonts_Utils' ) ) {
+	return;
+}
+
+/**
+ * Utility helpers for the Fonts API.
+ *
+ * @since X.X.X
+ * @deprecated 16.3.0 Fonts API is not supported.
+ */
+class WP_Fonts_Utils {
+
+	/**
+	 * Converts the given font family into a handle.
+	 *
+	 * @since X.X.X
+	 * @deprecated 16.3.0 This method is not supported.
+	 *
+	 * @return null
+	 */
+	public static function convert_font_family_into_handle() {
+		_deprecated_function( __METHOD__, 'Gutenberg 16.3.0' );
+		return null;
+	}
+
+	/**
+	 * Converts the given variation and its font-family into a handle.
+	 *
+	 * @since X.X.X
+	 * @deprecated 16.3.0 This method is not supported.
+	 *
+	 * @return null
+	 */
+	public static function convert_variation_into_handle() {
+		_deprecated_function( __METHOD__, 'Gutenberg 16.3.0' );
+		return null;
+	}
+
+	/**
+	 * Gets the font family from the variation.
+	 *
+	 * @since X.X.X
+	 * @deprecated 16.3.0 This method is not supported.
+	 *
+	 * @return null Null.
+	 */
+	public static function get_font_family_from_variation() {
+		_deprecated_function( __METHOD__, 'Gutenberg 16.3.0' );
+		return null;
+	}
+
+	/**
+	 * Checks if the given input is defined, i.e. meaning is a non-empty string.
+	 *
+	 * @since X.X.X
+	 * @deprecated 16.3.0
+	 *
+	 * @param string $input The input to check.
+	 * @return bool True when non-empty string. Else false.
+	 */
+	public static function is_defined( $input ) {
+		_deprecated_function( __METHOD__, 'Gutenberg 16.3.0' );
+		return ( is_string( $input ) && ! empty( $input ) );
+	}
+}