LibWeb: Implement TrustedTypes spec for set_value on Attribute

Author: tete17

Libraries/LibWeb/DOM/Attr.cpp

@@ -1,6 +1,7 @@
 /*
  * Copyright (c) 2021, Tim Flynn <trflynn89@serenityos.org>
  * Copyright (c) 2023, Luke Wilde <lukew@serenityos.org>
+ * Copyright (c) 2025, Miguel Sacristán Izcue <miguel_tete17@hotmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -13,6 +14,7 @@
 #include <LibWeb/DOM/MutationType.h>
 #include <LibWeb/DOM/StaticNodeList.h>
 #include <LibWeb/HTML/CustomElements/CustomElementReactionNames.h>
+#include <LibWeb/TrustedTypes/TrustedTypePolicy.h>
 
 namespace Web::DOM {
 
@@ -69,17 +71,43 @@ void Attr::set_owner_element(Element* owner_element)
     m_owner_element = owner_element;
 }
 
-// https://dom.spec.whatwg.org/#set-an-existing-attribute-value
-void Attr::set_value(String value)
+// FIXME: Trusted Types integration with DOM is still under review https://github.com/whatwg/dom/pull/1268
+// https://whatpr.org/dom/1268.html#set-an-existing-attribute-value
+WebIDL::ExceptionOr<void> Attr::set_value(String value)
 {
     // 1. If attribute’s element is null, then set attribute’s value to value.
     if (!owner_element()) {
         m_value = move(value);
     }
-    // 2. Otherwise, change attribute to value.
+    // 2. Otherwise:
     else {
-        change_attribute(move(value));
+        // 1. Let element be attribute’s element.
+        auto const* element = owner_element();
+
+        // 2. Let verifiedValue be the result of calling get Trusted Types-compliant attribute value with
+        //    attribute’s local name, attribute’s namespace, element, and value.
+        auto const verified_value = TRY(TrustedTypes::get_trusted_types_compliant_attribute_value(
+            local_name(),
+            namespace_uri().has_value() ? Utf16String::from_utf8(namespace_uri().value()) : Optional<Utf16String>(),
+            *element,
+            Utf16String::from_utf8(value)));
+
+        // 3. If attribute’s element is null, then set attribute’s value to verifiedValue, and return.
+        if (!owner_element()) {
+            m_value = verified_value.to_utf8_but_should_be_ported_to_utf16();
+            return {};
+        }
+
+        // 4. If attribute’s element is not element, then return.
+        if (owner_element() != element) {
+            return {};
+        }
+
+        // 5. Change attribute to verifiedValue.
+        change_attribute(verified_value.to_utf8_but_should_be_ported_to_utf16());
     }
+
+    return {};
 }
 
 // https://dom.spec.whatwg.org/#concept-element-attributes-change

Libraries/LibWeb/DOM/Attr.h

@@ -34,7 +34,7 @@ class WEB_API Attr final : public Node {
     FlyString const& lowercase_name() const { return m_lowercase_name; }
 
     String const& value() const { return m_value; }
-    void set_value(String value);
+    WebIDL::ExceptionOr<void> set_value(String value);
     void change_attribute(String value);
 
     Element* owner_element();

Libraries/LibWeb/DOM/NamedNodeMap.cpp

@@ -220,7 +220,7 @@ WebIDL::ExceptionOr<GC::Ptr<Attr>> NamedNodeMap::set_attribute(Attr& attribute)
         return &attribute;
 
     // 5. Set attr’s value to verifiedValue.
-    attribute.set_value(verifiedValue.to_utf8_but_should_be_ported_to_utf16());
+    TRY(attribute.set_value(verifiedValue.to_utf8_but_should_be_ported_to_utf16()));
 
     // 6. If oldAttr is non-null, then replace oldAttr with attr.
     if (old_attribute) {

Libraries/LibWeb/DOM/Node.cpp

@@ -221,7 +221,8 @@ void Node::set_text_content(Optional<Utf16String> const& maybe_content)
 
     // If Attr, set an existing attribute value with this and the given value.
     else if (auto* attribute = as_if<Attr>(*this)) {
-        attribute->set_value(content.to_utf8_but_should_be_ported_to_utf16());
+        // FIXME: This should propagate
+        MUST(attribute->set_value(content.to_utf8_but_should_be_ported_to_utf16()));
     }
 
     // Otherwise, do nothing.
@@ -368,21 +369,22 @@ Optional<String> Node::node_value() const
 }
 
 // https://dom.spec.whatwg.org/#ref-for-dom-node-nodevalue%E2%91%A0
-void Node::set_node_value(Optional<String> const& maybe_value)
+WebIDL::ExceptionOr<void> Node::set_node_value(Optional<String> const& maybe_value)
 {
     // The nodeValue setter steps are to, if the given value is null, act as if it was the empty string instead,
     // and then do as described below, switching on the interface this implements:
     auto value = maybe_value.value_or(String {});
 
     // If Attr, set an existing attribute value with this and the given value.
     if (auto* attr = as_if<Attr>(this)) {
-        attr->set_value(move(value));
+        TRY(attr->set_value(move(value)));
     } else if (auto* character_data = as_if<CharacterData>(this)) {
         // If CharacterData, replace data with node this, offset 0, count this’s length, and data the given value.
         character_data->set_data(Utf16String::from_utf8(value));
     }
 
     // Otherwise, do nothing.
+    return {};
 }
 
 // https://html.spec.whatwg.org/multipage/document-sequences.html#node-navigable

Libraries/LibWeb/DOM/Node.h

@@ -285,7 +285,7 @@ class WEB_API Node : public EventTarget
     WebIDL::ExceptionOr<void> normalize();
 
     Optional<String> node_value() const;
-    void set_node_value(Optional<String> const&);
+    WebIDL::ExceptionOr<void> set_node_value(Optional<String> const&);
 
     GC::Ptr<HTML::Navigable> navigable() const;