From a73c082f36fb8939720a7d86cad486bbf349b83c Mon Sep 17 00:00:00 2001
From: Tete17 <miguel_tete17@hotmail.com>
Date: Thu, 31 Jul 2025 00:55:34 +0200
Subject: [PATCH] LibWeb: Implement is_html method for TrustedTypePolicyFactory

This is used to check the legitimacy of a TrustedHTML object.
---
 .../LibWeb/TrustedTypes/TrustedTypePolicyFactory.cpp      | 8 ++++++++
 Libraries/LibWeb/TrustedTypes/TrustedTypePolicyFactory.h  | 2 ++
 .../LibWeb/TrustedTypes/TrustedTypePolicyFactory.idl      | 2 +-
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/Libraries/LibWeb/TrustedTypes/TrustedTypePolicyFactory.cpp b/Libraries/LibWeb/TrustedTypes/TrustedTypePolicyFactory.cpp
index c81379e0625..44ca95ba0af 100644
--- a/Libraries/LibWeb/TrustedTypes/TrustedTypePolicyFactory.cpp
+++ b/Libraries/LibWeb/TrustedTypes/TrustedTypePolicyFactory.cpp
@@ -15,6 +15,7 @@
 #include <LibWeb/HTML/WindowEventHandlers.h>
 #include <LibWeb/Namespace.h>
 #include <LibWeb/SVG/TagNames.h>
+#include <LibWeb/TrustedTypes/TrustedHTML.h>
 
 namespace Web::TrustedTypes {
 
@@ -132,6 +133,13 @@ void TrustedTypePolicyFactory::initialize(JS::Realm& realm)
     Base::initialize(realm);
 }
 
+// https://w3c.github.io/trusted-types/dist/spec/#dom-trustedtypepolicyfactory-ishtml
+bool TrustedTypePolicyFactory::is_html(JS::Value value)
+{
+    // 1. Returns true if value is an instance of TrustedHTML and has an associated data value set, false otherwise.
+    return value.is_object() && is<TrustedHTML>(value.as_object());
+}
+
 // https://w3c.github.io/trusted-types/dist/spec/#abstract-opdef-get-trusted-type-data-for-attribute
 Optional<TrustedTypeData> get_trusted_type_data_for_attribute(String const& element, String const& attribute, Optional<String> const& attribute_ns)
 {
diff --git a/Libraries/LibWeb/TrustedTypes/TrustedTypePolicyFactory.h b/Libraries/LibWeb/TrustedTypes/TrustedTypePolicyFactory.h
index 848b6274d34..d3f3bcca0d5 100644
--- a/Libraries/LibWeb/TrustedTypes/TrustedTypePolicyFactory.h
+++ b/Libraries/LibWeb/TrustedTypes/TrustedTypePolicyFactory.h
@@ -21,6 +21,8 @@ public:
 
     virtual ~TrustedTypePolicyFactory() override { }
 
+    bool is_html(JS::Value);
+
     Optional<String> get_attribute_type(String const& tag_name, String& attribute, Optional<String> element_ns, Optional<String> attr_ns);
     Optional<String> get_property_type(String const& tag_name, String const& property, Optional<String> element_ns);
 
diff --git a/Libraries/LibWeb/TrustedTypes/TrustedTypePolicyFactory.idl b/Libraries/LibWeb/TrustedTypes/TrustedTypePolicyFactory.idl
index b62b55532ea..9ea816b8d0a 100644
--- a/Libraries/LibWeb/TrustedTypes/TrustedTypePolicyFactory.idl
+++ b/Libraries/LibWeb/TrustedTypes/TrustedTypePolicyFactory.idl
@@ -3,7 +3,7 @@
 interface TrustedTypePolicyFactory {
     [FIXME] TrustedTypePolicy createPolicy(
         DOMString policyName, optional TrustedTypePolicyOptions policyOptions = {});
-    [FIXME] boolean isHTML(any value);
+    boolean isHTML(any value);
     [FIXME] boolean isScript(any value);
     [FIXME] boolean isScriptURL(any value);
     [FIXME] readonly attribute TrustedHTML emptyHTML;