LanguageServers: Add function to collect TODO entries in a document

Userland/DevTools/HackStudio/ToDoEntries.h

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2021, Federico Guerinoni <guerinoni.federico@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Function.h>
+#include <AK/HashMap.h>
+#include <AK/Noncopyable.h>
+#include <AK/String.h>
+
+namespace HackStudio {
+
+struct ToDoEntryPair {
+    String filename;
+    String comment;
+};
+
+class ToDoEntries {
+    AK_MAKE_NONCOPYABLE(ToDoEntries);
+
+public:
+    static ToDoEntries& the();
+
+    void set_entries(const String& filename, const Vector<String>&& entries);
+
+    Vector<ToDoEntryPair> get_entries();
+
+    Function<void()> on_update = nullptr;
+
+private:
+    ToDoEntries() = default;
+    HashMap<String, Vector<String>> m_document_to_entries;
+};
+
+}