Tag Processor: Add bookmark invalidation logic (#47559)

Invalidate bookmarks in a `WP_HTML_Tag_Processor` instance if the tags that they're pointing to have been replaced.

While `WP_HTML_Tag_Processor` currently only supports changing a given tag's attributes, we plan to also provide methods to make broader changes (possibly through a subclass of `WP_HTML_Tag_Processor`).

An API like that will have the potential of replacing a tag that a bookmark points to. As a preparation, we thus need to make sure that all bookmarks affected by a HTML replacement are invalidated (i.e. released).

Co-authored-by: Dennis Snell <[email protected]>

lib/compat/wordpress-6.3/html-api/class-gutenberg-html-tag-processor-6-3.php

@@ -1401,6 +1401,7 @@ private function class_name_updates_to_attributes_updates() {
 	 * Applies attribute updates to HTML document.
 	 *
 	 * @since 6.2.0
+	 * @since 6.3.0 Invalidate any bookmarks whose targets are overwritten.
 	 *
 	 * @return void
 	 */
@@ -1431,7 +1432,7 @@ private function apply_attributes_updates() {
 		 * Adjust bookmark locations to account for how the text
 		 * replacements adjust offsets in the input document.
 		 */
-		foreach ( $this->bookmarks as $bookmark ) {
+		foreach ( $this->bookmarks as $bookmark_name => $bookmark ) {
 			/*
 			 * Each lexical update which appears before the bookmark's endpoints
 			 * might shift the offsets for those endpoints. Loop through each change
@@ -1442,20 +1443,22 @@ private function apply_attributes_updates() {
 			$tail_delta = 0;
 
 			foreach ( $this->lexical_updates as $diff ) {
-				$update_head = $bookmark->start >= $diff->start;
-				$update_tail = $bookmark->end >= $diff->start;
-
-				if ( ! $update_head && ! $update_tail ) {
+				if ( $bookmark->start < $diff->start && $bookmark->end < $diff->start ) {
 					break;
 				}
 
+				if ( $bookmark->start >= $diff->start && $bookmark->end < $diff->end ) {
+					$this->release_bookmark( $bookmark_name );
+					continue 2;
+				}
+
 				$delta = strlen( $diff->text ) - ( $diff->end - $diff->start );
 
-				if ( $update_head ) {
+				if ( $bookmark->start >= $diff->start ) {
 					$head_delta += $delta;
 				}
 
-				if ( $update_tail ) {
+				if ( $bookmark->end >= $diff->end ) {
 					$tail_delta += $delta;
 				}
 			}
@@ -1467,6 +1470,18 @@ private function apply_attributes_updates() {
 		$this->lexical_updates = array();
 	}
 
+	/**
+	 * Checks whether a bookmark with the given name exists.
+	 *
+	 * @since 6.3.0
+	 *
+	 * @param string $bookmark_name Name to identify a bookmark that potentially exists.
+	 * @return bool Whether that bookmark exists.
+	 */
+	public function has_bookmark( $bookmark_name ) {
+		return array_key_exists( $bookmark_name, $this->bookmarks );
+	}
+
 	/**
 	 * Move the internal cursor in the Tag Processor to a given bookmark's location.
 	 *

phpunit/html-api/class-gutenberg-html-tag-processor-6-3-bookmark-test.php

@@ -0,0 +1,45 @@
+<?php
+/**
+ * Unit tests covering Gutenberg_HTML_Tag_Processor_6_3 functionality.
+ *
+ * @package WordPress
+ * @subpackage HTML
+ */
+
+require_once __DIR__ . '/../../lib/compat/wordpress-6.3/html-api/class-gutenberg-html-tag-processor-6-3.php';
+
+/**
+ * @group html-api
+ *
+ * @coversDefaultClass Gutenberg_HTML_Tag_Processor_6_3
+ */
+class Gutenberg_HTML_Tag_Processor_6_3_Bookmark_Test extends WP_UnitTestCase {
+	/**
+	 * @covers has_bookmark
+	 */
+	public function test_has_bookmark_returns_false_if_bookmark_does_not_exist() {
+		$p = new Gutenberg_HTML_Tag_Processor_6_3( '<div>Test</div>' );
+		$this->assertFalse( $p->has_bookmark( 'my-bookmark' ) );
+	}
+
+	/**
+	 * @covers has_bookmark
+	 */
+	public function test_has_bookmark_returns_true_if_bookmark_exists() {
+		$p = new Gutenberg_HTML_Tag_Processor_6_3( '<div>Test</div>' );
+		$p->next_tag();
+		$p->set_bookmark( 'my-bookmark' );
+		$this->assertTrue( $p->has_bookmark( 'my-bookmark' ) );
+	}
+
+	/**
+	 * @covers has_bookmark
+	 */
+	public function test_has_bookmark_returns_false_if_bookmark_has_been_released() {
+		$p = new Gutenberg_HTML_Tag_Processor_6_3( '<div>Test</div>' );
+		$p->next_tag();
+		$p->set_bookmark( 'my-bookmark' );
+		$p->release_bookmark( 'my-bookmark' );
+		$this->assertFalse( $p->has_bookmark( 'my-bookmark' ) );
+	}
+}