From b82a00d657d64f18dc82ff314baa231790825de5 Mon Sep 17 00:00:00 2001
From: Luke <luke.wilde@live.co.uk>
Date: Tue, 6 Apr 2021 19:35:52 +0100
Subject: [PATCH] LibWeb: Use the new "ensure_pre_insertion_validity" in the
 HTML document parser

Previously we didn't check if we could insert the element in the
adjusted insertion location's parent.

Also makes the return type NonnullRefPtr, as that's what element is.
---
 .../LibWeb/HTML/Parser/HTMLDocumentParser.cpp | 25 ++++++++++++++++---
 .../LibWeb/HTML/Parser/HTMLDocumentParser.h   |  4 +--
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/Userland/Libraries/LibWeb/HTML/Parser/HTMLDocumentParser.cpp b/Userland/Libraries/LibWeb/HTML/Parser/HTMLDocumentParser.cpp
index fd7a1655a3..0b63e9af4d 100644
--- a/Userland/Libraries/LibWeb/HTML/Parser/HTMLDocumentParser.cpp
+++ b/Userland/Libraries/LibWeb/HTML/Parser/HTMLDocumentParser.cpp
@@ -457,17 +457,34 @@ NonnullRefPtr<DOM::Element> HTMLDocumentParser::create_element_for(const HTMLTok
     return element;
 }
 
-RefPtr<DOM::Element> HTMLDocumentParser::insert_foreign_element(const HTMLToken& token, const FlyString& namespace_)
+// https://html.spec.whatwg.org/multipage/parsing.html#insert-a-foreign-element
+NonnullRefPtr<DOM::Element> HTMLDocumentParser::insert_foreign_element(const HTMLToken& token, const FlyString& namespace_)
 {
     auto adjusted_insertion_location = find_appropriate_place_for_inserting_node();
+
+    // FIXME: Pass in adjusted_insertion_location.parent as the intended parent.
     auto element = create_element_for(token, namespace_);
-    // FIXME: Check if it's possible to insert `element` at `adjusted_insertion_location`
-    adjusted_insertion_location.parent->insert_before(element, adjusted_insertion_location.insert_before_sibling);
+
+    auto pre_insertion_validity = adjusted_insertion_location.parent->ensure_pre_insertion_validity(element, adjusted_insertion_location.insert_before_sibling);
+
+    // NOTE: If it's not possible to insert the element at the adjusted insertion location, the element is simply dropped.
+    if (!pre_insertion_validity.is_exception()) {
+        if (!m_parsing_fragment) {
+            // FIXME: push a new element queue onto element's relevant agent's custom element reactions stack.
+        }
+
+        adjusted_insertion_location.parent->insert_before(element, adjusted_insertion_location.insert_before_sibling);
+
+        if (!m_parsing_fragment) {
+            // FIXME: pop the element queue from element's relevant agent's custom element reactions stack, and invoke custom element reactions in that queue.
+        }
+    }
+
     m_stack_of_open_elements.push(element);
     return element;
 }
 
-RefPtr<DOM::Element> HTMLDocumentParser::insert_html_element(const HTMLToken& token)
+NonnullRefPtr<DOM::Element> HTMLDocumentParser::insert_html_element(const HTMLToken& token)
 {
     return insert_foreign_element(token, Namespace::HTML);
 }
diff --git a/Userland/Libraries/LibWeb/HTML/Parser/HTMLDocumentParser.h b/Userland/Libraries/LibWeb/HTML/Parser/HTMLDocumentParser.h
index 4abbb74b72..4f1c4f2214 100644
--- a/Userland/Libraries/LibWeb/HTML/Parser/HTMLDocumentParser.h
+++ b/Userland/Libraries/LibWeb/HTML/Parser/HTMLDocumentParser.h
@@ -127,8 +127,8 @@ private:
 
     DOM::Text* find_character_insertion_node();
     void flush_character_insertions();
-    RefPtr<DOM::Element> insert_foreign_element(const HTMLToken&, const FlyString&);
-    RefPtr<DOM::Element> insert_html_element(const HTMLToken&);
+    NonnullRefPtr<DOM::Element> insert_foreign_element(const HTMLToken&, const FlyString&);
+    NonnullRefPtr<DOM::Element> insert_html_element(const HTMLToken&);
     DOM::Element& current_node();
     DOM::Element& adjusted_current_node();
     DOM::Element& node_before_current_node();