LibWeb: Introduce Mutation{Record,Observer} and observer microtasks

1 files changed, 38 insertions, 0 deletions

diff --git a/Userland/Libraries/LibWeb/DOM/MutationRecord.h b/Userland/Libraries/LibWeb/DOM/MutationRecord.h
new file mode 100644
index 0000000000..0c1b279400
--- /dev/null
+++ b/Userland/Libraries/LibWeb/DOM/MutationRecord.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2022, Luke Wilde <lukew@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/RefCounted.h>
+#include <LibWeb/Bindings/Wrappable.h>
+
+namespace Web::DOM {
+
+// https://dom.spec.whatwg.org/#mutationrecord
+// NOTE: This is implemented as a pure virtual interface with the actual implementation in the CPP file to prevent this circular dependency: Node.h -> MutationRecord.h -> MutationObserver.h -> Node.h
+//       This is also why this uses raw pointers and references, since using (NN)RP requires us to include the templated type, even in a header specifying a function return type.
+class MutationRecord
+    : public RefCounted<MutationRecord>
+    , public Bindings::Wrappable {
+public:
+    using WrapperType = Bindings::MutationRecordWrapper;
+
+    static NonnullRefPtr<MutationRecord> create(FlyString const& type, Node& target, NodeList& added_nodes, NodeList& removed_nodes, Node* previous_sibling, Node* next_sibling, String const& attribute_name, String const& attribute_namespace, String const& old_value);
+
+    virtual ~MutationRecord() override = default;
+
+    virtual FlyString const& type() const = 0;
+    virtual Node const* target() const = 0;
+    virtual NodeList const* added_nodes() const = 0;
+    virtual NodeList const* removed_nodes() const = 0;
+    virtual Node const* previous_sibling() const = 0;
+    virtual Node const* next_sibling() const = 0;
+    virtual String const& attribute_name() const = 0;
+    virtual String const& attribute_namespace() const = 0;
+    virtual String const& old_value() const = 0;
+};
+
+}