From 6f235ad93f48107d48607f7315ff1372915144f0 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Sun, 22 Mar 2020 21:20:40 +0100
Subject: [PATCH] LibWeb: Implement cancelAnimationFrame()

These functions (rAF and cAF) should eventually stop using raw ID's
from GUI::DisplayLink as their identifiers. That's a FIXME for now. :^)
---
 Libraries/LibWeb/DOM/Document.cpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Libraries/LibWeb/DOM/Document.cpp b/Libraries/LibWeb/DOM/Document.cpp
index 4f7498c2ec..058c702d29 100644
--- a/Libraries/LibWeb/DOM/Document.cpp
+++ b/Libraries/LibWeb/DOM/Document.cpp
@@ -373,6 +373,7 @@ JS::Interpreter& Document::interpreter()
             ASSERT(arguments[0].is_object());
             ASSERT(arguments[0].as_object()->is_function());
             auto callback = make_handle(const_cast<JS::Object*>(arguments[0].as_object()));
+            // FIXME: Don't hand out raw DisplayLink ID's to JavaScript!
             i32 link_id = GUI::DisplayLink::register_callback([this, callback](i32 link_id) {
                 const_cast<JS::Function*>(static_cast<const JS::Function*>(callback.cell()))->call(*m_interpreter, {});
                 GUI::DisplayLink::unregister_callback(link_id);
@@ -380,6 +381,14 @@ JS::Interpreter& Document::interpreter()
             return JS::Value(link_id);
         });
 
+        m_interpreter->global_object().put_native_function("cancelAnimationFrame", [](JS::Object*, const Vector<JS::Value>& arguments) -> JS::Value {
+            if (arguments.size() < 1)
+                return JS::js_undefined();
+            // FIXME: We should not be passing untrusted numbers to DisplayLink::unregistered_callback()!
+            GUI::DisplayLink::unregister_callback(arguments[0].to_i32());
+            return JS::js_undefined();
+        });
+
         m_interpreter->global_object().put_native_property(
             "document",
             [this](JS::Object*) {