diff -r 7b1b88e27a20 -r 48c4eec2b7e6 wp/wp-includes/html-api/class-wp-html-processor-state.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wp/wp-includes/html-api/class-wp-html-processor-state.php	Fri Sep 05 18:40:08 2025 +0200
@@ -0,0 +1,143 @@
+<?php
+/**
+ * HTML API: WP_HTML_Processor_State class
+ *
+ * @package WordPress
+ * @subpackage HTML-API
+ * @since 6.4.0
+ */
+
+/**
+ * Core class used by the HTML processor during HTML parsing
+ * for managing the internal parsing state.
+ *
+ * This class is designed for internal use by the HTML processor.
+ *
+ * @since 6.4.0
+ *
+ * @access private
+ *
+ * @see WP_HTML_Processor
+ */
+class WP_HTML_Processor_State {
+	/*
+	 * Insertion mode constants.
+	 *
+	 * These constants exist and are named to make it easier to
+	 * discover and recognize the supported insertion modes in
+	 * the parser.
+	 *
+	 * Out of all the possible insertion modes, only those
+	 * supported by the parser are listed here. As support
+	 * is added to the parser for more modes, add them here
+	 * following the same naming and value pattern.
+	 *
+	 * @see https://html.spec.whatwg.org/#the-insertion-mode
+	 */
+
+	/**
+	 * Initial insertion mode for full HTML parser.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @see https://html.spec.whatwg.org/#the-initial-insertion-mode
+	 * @see WP_HTML_Processor_State::$insertion_mode
+	 *
+	 * @var string
+	 */
+	const INSERTION_MODE_INITIAL = 'insertion-mode-initial';
+
+	/**
+	 * In body insertion mode for full HTML parser.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @see https://html.spec.whatwg.org/#parsing-main-inbody
+	 * @see WP_HTML_Processor_State::$insertion_mode
+	 *
+	 * @var string
+	 */
+	const INSERTION_MODE_IN_BODY = 'insertion-mode-in-body';
+
+	/**
+	 * Tracks open elements while scanning HTML.
+	 *
+	 * This property is initialized in the constructor and never null.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @see https://html.spec.whatwg.org/#stack-of-open-elements
+	 *
+	 * @var WP_HTML_Open_Elements
+	 */
+	public $stack_of_open_elements = null;
+
+	/**
+	 * Tracks open formatting elements, used to handle mis-nested formatting element tags.
+	 *
+	 * This property is initialized in the constructor and never null.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @see https://html.spec.whatwg.org/#list-of-active-formatting-elements
+	 *
+	 * @var WP_HTML_Active_Formatting_Elements
+	 */
+	public $active_formatting_elements = null;
+
+	/**
+	 * Refers to the currently-matched tag, if any.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @var WP_HTML_Token|null
+	 */
+	public $current_token = null;
+
+	/**
+	 * Tree construction insertion mode.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @see https://html.spec.whatwg.org/#insertion-mode
+	 *
+	 * @var string
+	 */
+	public $insertion_mode = self::INSERTION_MODE_INITIAL;
+
+	/**
+	 * Context node initializing fragment parser, if created as a fragment parser.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @see https://html.spec.whatwg.org/#concept-frag-parse-context
+	 *
+	 * @var [string, array]|null
+	 */
+	public $context_node = null;
+
+	/**
+	 * The frameset-ok flag indicates if a `FRAMESET` element is allowed in the current state.
+	 *
+	 * > The frameset-ok flag is set to "ok" when the parser is created. It is set to "not ok" after certain tokens are seen.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @see https://html.spec.whatwg.org/#frameset-ok-flag
+	 *
+	 * @var bool
+	 */
+	public $frameset_ok = true;
+
+	/**
+	 * Constructor - creates a new and empty state value.
+	 *
+	 * @since 6.4.0
+	 *
+	 * @see WP_HTML_Processor
+	 */
+	public function __construct() {
+		$this->stack_of_open_elements     = new WP_HTML_Open_Elements();
+		$this->active_formatting_elements = new WP_HTML_Active_Formatting_Elements();
+	}
+}