From 41f3817b36f4dd08f3d3ce612adfd6bad2a59950 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Wed, 18 Mar 2020 20:05:15 +0100
Subject: [PATCH] LibWeb: Use a JS::Handle to keep the EventListener function
 alive

---
 Libraries/LibWeb/Bindings/EventListenerWrapper.cpp |  6 ------
 Libraries/LibWeb/Bindings/EventListenerWrapper.h   |  1 -
 Libraries/LibWeb/Bindings/EventTargetWrapper.cpp   |  4 ++--
 Libraries/LibWeb/DOM/EventListener.cpp             | 11 +++++++++++
 Libraries/LibWeb/DOM/EventListener.h               | 10 +++++-----
 5 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/Libraries/LibWeb/Bindings/EventListenerWrapper.cpp b/Libraries/LibWeb/Bindings/EventListenerWrapper.cpp
index d01d5fa15b..0948d29d45 100644
--- a/Libraries/LibWeb/Bindings/EventListenerWrapper.cpp
+++ b/Libraries/LibWeb/Bindings/EventListenerWrapper.cpp
@@ -14,11 +14,5 @@ EventListenerWrapper::~EventListenerWrapper()
 {
 }
 
-void EventListenerWrapper::visit_children(JS::Cell::Visitor& visitor)
-{
-    Wrapper::visit_children(visitor);
-    visitor.visit(impl().function());
-}
-
 }
 }
diff --git a/Libraries/LibWeb/Bindings/EventListenerWrapper.h b/Libraries/LibWeb/Bindings/EventListenerWrapper.h
index c3a3bcc86d..c049275816 100644
--- a/Libraries/LibWeb/Bindings/EventListenerWrapper.h
+++ b/Libraries/LibWeb/Bindings/EventListenerWrapper.h
@@ -41,7 +41,6 @@ public:
 
 private:
     virtual const char* class_name() const override { return "EventListenerWrapper"; }
-    virtual void visit_children(JS::Cell::Visitor&) override;
 
     NonnullRefPtr<EventListener> m_impl;
 };
diff --git a/Libraries/LibWeb/Bindings/EventTargetWrapper.cpp b/Libraries/LibWeb/Bindings/EventTargetWrapper.cpp
index 0d92f395e4..0d30ec086f 100644
--- a/Libraries/LibWeb/Bindings/EventTargetWrapper.cpp
+++ b/Libraries/LibWeb/Bindings/EventTargetWrapper.cpp
@@ -18,8 +18,8 @@ EventTargetWrapper::EventTargetWrapper(EventTarget& impl)
         auto event_name = arguments[0].to_string();
         ASSERT(arguments[1].is_object());
         ASSERT(arguments[1].as_object()->is_function());
-        auto listener = adopt(*new EventListener(static_cast<JS::Function*>(const_cast<Object*>(arguments[1].as_object()))));
-        wrap(this_object->heap(), *listener);
+        auto* function = static_cast<JS::Function*>(const_cast<Object*>(arguments[1].as_object()));
+        auto listener = adopt(*new EventListener(JS::make_handle(function)));
         static_cast<EventTargetWrapper*>(this_object)->impl().add_event_listener(event_name, move(listener));
         return JS::js_undefined();
     });
diff --git a/Libraries/LibWeb/DOM/EventListener.cpp b/Libraries/LibWeb/DOM/EventListener.cpp
index e69de29bb2..4cad68964a 100644
--- a/Libraries/LibWeb/DOM/EventListener.cpp
+++ b/Libraries/LibWeb/DOM/EventListener.cpp
@@ -0,0 +1,11 @@
+#include <LibJS/Runtime/Function.h>
+#include <LibWeb/DOM/EventListener.h>
+
+namespace Web {
+
+JS::Function* EventListener::function()
+{
+    return m_function.cell();
+}
+
+}
diff --git a/Libraries/LibWeb/DOM/EventListener.h b/Libraries/LibWeb/DOM/EventListener.h
index e6e3a8ede9..1c32d919b7 100644
--- a/Libraries/LibWeb/DOM/EventListener.h
+++ b/Libraries/LibWeb/DOM/EventListener.h
@@ -1,7 +1,7 @@
 #pragma once
 
 #include <AK/RefCounted.h>
-#include <LibJS/Forward.h>
+#include <LibJS/Heap/Handle.h>
 #include <LibWeb/Bindings/Wrappable.h>
 
 namespace Web {
@@ -12,15 +12,15 @@ class EventListener
 public:
     using WrapperType = Bindings::EventListenerWrapper;
 
-    explicit EventListener(JS::Function* function)
-        : m_function(function)
+    explicit EventListener(JS::Handle<JS::Function> function)
+        : m_function(move(function))
     {
     }
 
-    JS::Function* function() { return m_function; }
+    JS::Function* function();
 
 private:
-    JS::Function* m_function { nullptr };
+    JS::Handle<JS::Function> m_function;
 };
 
 }