From c12728632d40697a4ce6ae53b027a614a45e5f09 Mon Sep 17 00:00:00 2001
From: Timothy Flynn <trflynn89@pm.me>
Date: Wed, 2 Jul 2025 12:29:07 -0400
Subject: [PATCH] LibDevTools: Handle pseudo elements during DOM node
 serialization

We need to tell DevTools whether elements are pseudo elements, and we
need to set the element's type and visibility to that of its parent.
---
 Libraries/LibDevTools/Actors/WalkerActor.cpp | 59 +++++++++++++++-----
 1 file changed, 44 insertions(+), 15 deletions(-)

diff --git a/Libraries/LibDevTools/Actors/WalkerActor.cpp b/Libraries/LibDevTools/Actors/WalkerActor.cpp
index 83230edb150..2362cf92309 100644
--- a/Libraries/LibDevTools/Actors/WalkerActor.cpp
+++ b/Libraries/LibDevTools/Actors/WalkerActor.cpp
@@ -388,6 +388,19 @@ JsonValue WalkerActor::serialize_root() const
     return serialize_node(m_dom_tree);
 }
 
+static constexpr Web::DOM::NodeType parse_node_type(StringView type)
+{
+    if (type == "document"sv)
+        return Web::DOM::NodeType::DOCUMENT_NODE;
+    if (type == "element"sv)
+        return Web::DOM::NodeType::ELEMENT_NODE;
+    if (type == "text"sv)
+        return Web::DOM::NodeType::TEXT_NODE;
+    if (type == "comment"sv)
+        return Web::DOM::NodeType::COMMENT_NODE;
+    return Web::DOM::NodeType::INVALID;
+}
+
 JsonValue WalkerActor::serialize_node(JsonObject const& node) const
 {
     auto tab = m_tab.strong_ref();
@@ -401,30 +414,46 @@ JsonValue WalkerActor::serialize_node(JsonObject const& node) const
     auto name = node.get_string("name"sv).release_value();
     auto type = node.get_string("type"sv).release_value();
 
-    auto dom_type = Web::DOM::NodeType::INVALID;
+    auto dom_type = parse_node_type(type);
     JsonValue node_value;
 
     auto is_top_level_document = &node == &m_dom_tree;
     auto is_displayed = !is_top_level_document && node.get_bool("visible"sv).value_or(false);
     auto is_scrollable = node.get_bool("scrollable"sv).value_or(false);
+
     auto is_shadow_root = false;
+    auto is_after_pseudo_element = false;
+    auto is_before_pseudo_element = false;
+    auto is_marker_pseudo_element = false;
 
-    if (type == "document"sv) {
-        dom_type = Web::DOM::NodeType::DOCUMENT_NODE;
-    } else if (type == "element"sv) {
-        dom_type = Web::DOM::NodeType::ELEMENT_NODE;
-    } else if (type == "text"sv) {
-        dom_type = Web::DOM::NodeType::TEXT_NODE;
-
+    if (dom_type == Web::DOM::NodeType::TEXT_NODE) {
         if (auto text = node.get_string("text"sv); text.has_value())
             node_value = text.release_value();
-    } else if (type == "comment"sv) {
-        dom_type = Web::DOM::NodeType::COMMENT_NODE;
-
+    } else if (dom_type == Web::DOM::NodeType::COMMENT_NODE) {
         if (auto data = node.get_string("data"sv); data.has_value())
             node_value = data.release_value();
-    } else if (type == "shadow-root"sv) {
+    }
+
+    if (type == "shadow-root"sv) {
         is_shadow_root = true;
+    } else if (type == "pseudo-element"sv) {
+        auto pseudo_element = node.get_integer<UnderlyingType<Web::CSS::PseudoElement>>("pseudo-element"sv).map([](auto value) {
+            VERIFY(value < to_underlying(Web::CSS::PseudoElement::KnownPseudoElementCount));
+            return static_cast<Web::CSS::PseudoElement>(value);
+        });
+
+        is_after_pseudo_element = pseudo_element == Web::CSS::PseudoElement::After;
+        is_before_pseudo_element = pseudo_element == Web::CSS::PseudoElement::Before;
+        is_marker_pseudo_element = pseudo_element == Web::CSS::PseudoElement::Marker;
+
+        auto parent_id = node.get_integer<Web::UniqueNodeID::Type>("parent-id"sv).value();
+
+        if (auto parent_actor = m_dom_node_id_to_actor_map.get(parent_id); parent_actor.has_value()) {
+            if (auto parent_node = WalkerActor::dom_node_for(this, *parent_actor); parent_node.has_value()) {
+                dom_type = parse_node_type(parent_node->node.get_string("type"sv).value());
+                is_displayed = !is_top_level_document && parent_node->node.get_bool("visible"sv).value_or(false);
+            }
+        }
     }
 
     size_t child_count = 0;
@@ -454,13 +483,13 @@ JsonValue WalkerActor::serialize_node(JsonObject const& node) const
     serialized.set("displayName"sv, name.to_ascii_lowercase());
     serialized.set("displayType"sv, "block"sv);
     serialized.set("hasEventListeners"sv, false);
-    serialized.set("isAfterPseudoElement"sv, false);
+    serialized.set("isAfterPseudoElement"sv, is_after_pseudo_element);
     serialized.set("isAnonymous"sv, false);
-    serialized.set("isBeforePseudoElement"sv, false);
+    serialized.set("isBeforePseudoElement"sv, is_before_pseudo_element);
     serialized.set("isDirectShadowHostChild"sv, JsonValue {});
     serialized.set("isDisplayed"sv, is_displayed);
     serialized.set("isInHTMLDocument"sv, true);
-    serialized.set("isMarkerPseudoElement"sv, false);
+    serialized.set("isMarkerPseudoElement"sv, is_marker_pseudo_element);
     serialized.set("isNativeAnonymous"sv, false);
     serialized.set("isScrollable"sv, is_scrollable);
     serialized.set("isShadowHost"sv, false);