diff -r 7b1b88e27a20 -r 48c4eec2b7e6 wp/wp-includes/fonts/class-wp-font-face.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wp/wp-includes/fonts/class-wp-font-face.php	Fri Sep 05 18:40:08 2025 +0200
@@ -0,0 +1,430 @@
+<?php
+/**
+ * WP_Font_Face class.
+ *
+ * @package    WordPress
+ * @subpackage Fonts
+ * @since      6.4.0
+ */
+
+/**
+ * Font Face generates and prints `@font-face` styles for given fonts.
+ *
+ * @since 6.4.0
+ */
+class WP_Font_Face {
+
+	/**
+	 * The font-face property defaults.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @var string[]
+	 */
+	private $font_face_property_defaults = array(
+		'font-family'  => '',
+		'font-style'   => 'normal',
+		'font-weight'  => '400',
+		'font-display' => 'fallback',
+	);
+
+	/**
+	 * Valid font-face property names.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @var string[]
+	 */
+	private $valid_font_face_properties = array(
+		'ascent-override',
+		'descent-override',
+		'font-display',
+		'font-family',
+		'font-stretch',
+		'font-style',
+		'font-weight',
+		'font-variant',
+		'font-feature-settings',
+		'font-variation-settings',
+		'line-gap-override',
+		'size-adjust',
+		'src',
+		'unicode-range',
+	);
+
+	/**
+	 * Valid font-display values.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @var string[]
+	 */
+	private $valid_font_display = array( 'auto', 'block', 'fallback', 'swap', 'optional' );
+
+	/**
+	 * Array of font-face style tag's attribute(s)
+	 * where the key is the attribute name and the
+	 * value is its value.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @var string[]
+	 */
+	private $style_tag_attrs = array();
+
+	/**
+	 * Creates and initializes an instance of WP_Font_Face.
+	 *
+	 * @since 6.4.0
+	 */
+	public function __construct() {
+		if (
+			function_exists( 'is_admin' ) && ! is_admin()
+			&&
+			function_exists( 'current_theme_supports' ) && ! current_theme_supports( 'html5', 'style' )
+		) {
+			$this->style_tag_attrs = array( 'type' => 'text/css' );
+		}
+	}
+
+	/**
+	 * Generates and prints the `@font-face` styles for the given fonts.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @param array[][] $fonts Optional. The font-families and their font variations.
+	 *                         See {@see wp_print_font_faces()} for the supported fields.
+	 *                         Default empty array.
+	 */
+	public function generate_and_print( array $fonts ) {
+		$fonts = $this->validate_fonts( $fonts );
+
+		// Bail out if there are no fonts are given to process.
+		if ( empty( $fonts ) ) {
+			return;
+		}
+
+		$css = $this->get_css( $fonts );
+
+		/*
+		 * The font-face CSS is contained within <style> tags and can only be interpreted
+		 * as CSS in the browser. Using wp_strip_all_tags() is sufficient escaping
+		 * to avoid malicious attempts to close </style> and open a <script>.
+		 */
+		$css = wp_strip_all_tags( $css );
+
+		// Bail out if there is no CSS to print.
+		if ( empty( $css ) ) {
+			return;
+		}
+
+		printf( $this->get_style_element(), $css );
+	}
+
+	/**
+	 * Validates each of the font-face properties.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @param array $fonts The fonts to valid.
+	 * @return array Prepared font-faces organized by provider and font-family.
+	 */
+	private function validate_fonts( array $fonts ) {
+		$validated_fonts = array();
+
+		foreach ( $fonts as $font_faces ) {
+			foreach ( $font_faces as $font_face ) {
+				$font_face = $this->validate_font_face_declarations( $font_face );
+				// Skip if failed validation.
+				if ( false === $font_face ) {
+					continue;
+				}
+
+				$validated_fonts[] = $font_face;
+			}
+		}
+
+		return $validated_fonts;
+	}
+
+	/**
+	 * Validates each font-face declaration (property and value pairing).
+	 *
+	 * @since 6.4.0
+	 *
+	 * @param array $font_face Font face property and value pairings to validate.
+	 * @return array|false Validated font-face on success, or false on failure.
+	 */
+	private function validate_font_face_declarations( array $font_face ) {
+		$font_face = wp_parse_args( $font_face, $this->font_face_property_defaults );
+
+		// Check the font-family.
+		if ( empty( $font_face['font-family'] ) || ! is_string( $font_face['font-family'] ) ) {
+			// @todo replace with `wp_trigger_error()`.
+			_doing_it_wrong(
+				__METHOD__,
+				__( 'Font font-family must be a non-empty string.' ),
+				'6.4.0'
+			);
+			return false;
+		}
+
+		// Make sure that local fonts have 'src' defined.
+		if ( empty( $font_face['src'] ) || ( ! is_string( $font_face['src'] ) && ! is_array( $font_face['src'] ) ) ) {
+			// @todo replace with `wp_trigger_error()`.
+			_doing_it_wrong(
+				__METHOD__,
+				__( 'Font src must be a non-empty string or an array of strings.' ),
+				'6.4.0'
+			);
+			return false;
+		}
+
+		// Validate the 'src' property.
+		foreach ( (array) $font_face['src'] as $src ) {
+			if ( empty( $src ) || ! is_string( $src ) ) {
+				// @todo replace with `wp_trigger_error()`.
+				_doing_it_wrong(
+					__METHOD__,
+					__( 'Each font src must be a non-empty string.' ),
+					'6.4.0'
+				);
+				return false;
+			}
+		}
+
+		// Check the font-weight.
+		if ( ! is_string( $font_face['font-weight'] ) && ! is_int( $font_face['font-weight'] ) ) {
+			// @todo replace with `wp_trigger_error()`.
+			_doing_it_wrong(
+				__METHOD__,
+				__( 'Font font-weight must be a properly formatted string or integer.' ),
+				'6.4.0'
+			);
+			return false;
+		}
+
+		// Check the font-display.
+		if ( ! in_array( $font_face['font-display'], $this->valid_font_display, true ) ) {
+			$font_face['font-display'] = $this->font_face_property_defaults['font-display'];
+		}
+
+		// Remove invalid properties.
+		foreach ( $font_face as $property => $value ) {
+			if ( ! in_array( $property, $this->valid_font_face_properties, true ) ) {
+				unset( $font_face[ $property ] );
+			}
+		}
+
+		return $font_face;
+	}
+
+	/**
+	 * Gets the style element for wrapping the `@font-face` CSS.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @return string The style element.
+	 */
+	private function get_style_element() {
+		$attributes = $this->generate_style_element_attributes();
+
+		return "<style id='wp-fonts-local'{$attributes}>\n%s\n</style>\n";
+	}
+
+	/**
+	 * Gets the defined <style> element's attributes.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @return string A string of attribute=value when defined, else, empty string.
+	 */
+	private function generate_style_element_attributes() {
+		$attributes = '';
+		foreach ( $this->style_tag_attrs as $name => $value ) {
+			$attributes .= " {$name}='{$value}'";
+		}
+		return $attributes;
+	}
+
+	/**
+	 * Gets the `@font-face` CSS styles for locally-hosted font files.
+	 *
+	 * This method does the following processing tasks:
+	 *    1. Orchestrates an optimized `src` (with format) for browser support.
+	 *    2. Generates the `@font-face` for all its fonts.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @param array[] $font_faces The font-faces to generate @font-face CSS styles.
+	 * @return string The `@font-face` CSS styles.
+	 */
+	private function get_css( $font_faces ) {
+		$css = '';
+
+		foreach ( $font_faces as $font_face ) {
+				// Order the font's `src` items to optimize for browser support.
+				$font_face = $this->order_src( $font_face );
+
+				// Build the @font-face CSS for this font.
+				$css .= '@font-face{' . $this->build_font_face_css( $font_face ) . '}' . "\n";
+		}
+
+		// Don't print the last newline character.
+		return rtrim( $css, "\n" );
+	}
+
+	/**
+	 * Orders `src` items to optimize for browser support.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @param array $font_face Font face to process.
+	 * @return array Font-face with ordered src items.
+	 */
+	private function order_src( array $font_face ) {
+		if ( ! is_array( $font_face['src'] ) ) {
+			$font_face['src'] = (array) $font_face['src'];
+		}
+
+		$src         = array();
+		$src_ordered = array();
+
+		foreach ( $font_face['src'] as $url ) {
+			// Add data URIs first.
+			if ( str_starts_with( trim( $url ), 'data:' ) ) {
+				$src_ordered[] = array(
+					'url'    => $url,
+					'format' => 'data',
+				);
+				continue;
+			}
+			$format         = pathinfo( $url, PATHINFO_EXTENSION );
+			$src[ $format ] = $url;
+		}
+
+		// Add woff2.
+		if ( ! empty( $src['woff2'] ) ) {
+			$src_ordered[] = array(
+				'url'    => $src['woff2'],
+				'format' => 'woff2',
+			);
+		}
+
+		// Add woff.
+		if ( ! empty( $src['woff'] ) ) {
+			$src_ordered[] = array(
+				'url'    => $src['woff'],
+				'format' => 'woff',
+			);
+		}
+
+		// Add ttf.
+		if ( ! empty( $src['ttf'] ) ) {
+			$src_ordered[] = array(
+				'url'    => $src['ttf'],
+				'format' => 'truetype',
+			);
+		}
+
+		// Add eot.
+		if ( ! empty( $src['eot'] ) ) {
+			$src_ordered[] = array(
+				'url'    => $src['eot'],
+				'format' => 'embedded-opentype',
+			);
+		}
+
+		// Add otf.
+		if ( ! empty( $src['otf'] ) ) {
+			$src_ordered[] = array(
+				'url'    => $src['otf'],
+				'format' => 'opentype',
+			);
+		}
+		$font_face['src'] = $src_ordered;
+
+		return $font_face;
+	}
+
+	/**
+	 * Builds the font-family's CSS.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @param array $font_face Font face to process.
+	 * @return string This font-family's CSS.
+	 */
+	private function build_font_face_css( array $font_face ) {
+		$css = '';
+
+		/*
+		 * Wrap font-family in quotes if it contains spaces
+		 * and is not already wrapped in quotes.
+		 */
+		if (
+			str_contains( $font_face['font-family'], ' ' ) &&
+			! str_contains( $font_face['font-family'], '"' ) &&
+			! str_contains( $font_face['font-family'], "'" )
+		) {
+			$font_face['font-family'] = '"' . $font_face['font-family'] . '"';
+		}
+
+		foreach ( $font_face as $key => $value ) {
+			// Compile the "src" parameter.
+			if ( 'src' === $key ) {
+				$value = $this->compile_src( $value );
+			}
+
+			// If font-variation-settings is an array, convert it to a string.
+			if ( 'font-variation-settings' === $key && is_array( $value ) ) {
+				$value = $this->compile_variations( $value );
+			}
+
+			if ( ! empty( $value ) ) {
+				$css .= "$key:$value;";
+			}
+		}
+
+		return $css;
+	}
+
+	/**
+	 * Compiles the `src` into valid CSS.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @param array $value Value to process.
+	 * @return string The CSS.
+	 */
+	private function compile_src( array $value ) {
+		$src = '';
+
+		foreach ( $value as $item ) {
+			$src .= ( 'data' === $item['format'] )
+				? ", url({$item['url']})"
+				: ", url('{$item['url']}') format('{$item['format']}')";
+		}
+
+		$src = ltrim( $src, ', ' );
+		return $src;
+	}
+
+	/**
+	 * Compiles the font variation settings.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @param array $font_variation_settings Array of font variation settings.
+	 * @return string The CSS.
+	 */
+	private function compile_variations( array $font_variation_settings ) {
+		$variations = '';
+
+		foreach ( $font_variation_settings as $key => $value ) {
+			$variations .= "$key $value";
+		}
+
+		return $variations;
+	}
+}