From 40e7f644331debc4eac67e64ffa636178e2aab26 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Sat, 17 Dec 2022 10:19:35 +0100
Subject: [PATCH] LibWeb: Implement most of "destroy a top-level traversable"

Co-authored-by: Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>
---
 .../LibWeb/HTML/TraversableNavigable.cpp      | 27 +++++++++++++++++++
 .../LibWeb/HTML/TraversableNavigable.h        |  2 ++
 2 files changed, 29 insertions(+)

diff --git a/Userland/Libraries/LibWeb/HTML/TraversableNavigable.cpp b/Userland/Libraries/LibWeb/HTML/TraversableNavigable.cpp
index 84a7c3b826a..2a118284d05 100644
--- a/Userland/Libraries/LibWeb/HTML/TraversableNavigable.cpp
+++ b/Userland/Libraries/LibWeb/HTML/TraversableNavigable.cpp
@@ -508,4 +508,31 @@ void TraversableNavigable::apply_pending_history_changes()
     apply_the_history_step(target_step);
 }
 
+// https://html.spec.whatwg.org/multipage/document-sequences.html#destroy-a-top-level-traversable
+void TraversableNavigable::destroy_top_level_traversable()
+{
+    VERIFY(is_top_level_traversable());
+
+    // 1. Let browsingContext be traversable's active browsing context.
+    auto browsing_context = active_browsing_context();
+
+    // 2. For each historyEntry in traversable's session history entries:
+    for (auto& history_entry : m_session_history_entries) {
+        // 1. Let document be historyEntry's document.
+        auto document = history_entry->document_state->document();
+
+        // 2. If document is not null, then destroy document.
+        if (document)
+            document->destroy();
+    }
+
+    // 3. Remove browsingContext.
+    browsing_context->remove();
+
+    // FIXME: 4. Remove traversable from the user interface (e.g., close or hide its tab in a tabbed browser).
+
+    // 5. Remove traversable from the user agent's top-level traversable set.
+    user_agent_top_level_traversable_set().remove(this);
+}
+
 }
diff --git a/Userland/Libraries/LibWeb/HTML/TraversableNavigable.h b/Userland/Libraries/LibWeb/HTML/TraversableNavigable.h
index f6e71fa83c4..2902fbcc4f0 100644
--- a/Userland/Libraries/LibWeb/HTML/TraversableNavigable.h
+++ b/Userland/Libraries/LibWeb/HTML/TraversableNavigable.h
@@ -45,6 +45,8 @@ public:
     void clear_the_forward_session_history();
     void traverse_the_history_by_delta(int delta);
 
+    void destroy_top_level_traversable();
+
 private:
     TraversableNavigable();