LibWeb: Implement the <summary> element

Userland/Libraries/LibWeb/HTML/HTMLSummaryElement.cpp

@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2023, the SerenityOS developers.
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <LibWeb/Bindings/Intrinsics.h>
+#include <LibWeb/HTML/HTMLDetailsElement.h>
+#include <LibWeb/HTML/HTMLSummaryElement.h>
+
+namespace Web::HTML {
+
+HTMLSummaryElement::HTMLSummaryElement(DOM::Document& document, DOM::QualifiedName qualified_name)
+    : HTMLElement(document, move(qualified_name))
+{
+    activation_behavior = [this](auto&) {
+        // The activation behavior of summary elements is to run the following steps:
+
+        // 1. If this summary element is not the summary for its parent details, then return.
+        if (!is_summary_for_its_parent_details())
+            return;
+
+        // 2. Let parent be this summary element's parent.
+        auto* parent = this->parent_element();
+
+        // 3. If the open attribute is present on parent, then remove it. Otherwise, set parent's open attribute to the empty string.
+        if (parent->has_attribute(HTML::AttributeNames::open))
+            parent->remove_attribute(HTML::AttributeNames::open);
+        else
+            parent->set_attribute(HTML::AttributeNames::open, "").release_value_but_fixme_should_propagate_errors();
+    };
+}
+
+// https://html.spec.whatwg.org/multipage/interactive-elements.html#summary-for-its-parent-details
+bool HTMLSummaryElement::is_summary_for_its_parent_details()
+{
+    // A summary element is a summary for its parent details if the following algorithm returns true:
+
+    // 1. If this summary element has no parent, then return false.
+    if (!parent_element())
+        return false;
+
+    // 2. Let parent be this summary element's parent.
+    auto* parent = this->parent_element();
+
+    // 3. If parent is not a details element, then return false.
+    if (!is<HTMLDetailsElement>(*parent))
+        return false;
+
+    // 4. If parent's first summary element child is not this summary element, then return false.
+    if (parent->first_child_of_type<HTMLSummaryElement>() != this)
+        return false;
+
+    // 5. Return true.
+    return true;
+}
+
+HTMLSummaryElement::~HTMLSummaryElement() = default;
+
+JS::ThrowCompletionOr<void> HTMLSummaryElement::initialize(JS::Realm& realm)
+{
+    MUST_OR_THROW_OOM(Base::initialize(realm));
+
+    return {};
+}
+
+}