initial commit

include/query_scheduler.hpp

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <functional>
+#include <mutex>
+
+class DaliQueryScheduler {
+ public:
+  static DaliQueryScheduler& instance() {
+    static DaliQueryScheduler inst;
+    return inst;
+  }
+
+  template <typename Fn>
+  auto run(Fn&& action) -> decltype(action()) {
+    std::lock_guard<std::mutex> lock(mu_);
+    return action();
+  }
+
+ private:
+  DaliQueryScheduler() = default;
+  std::mutex mu_;
+};