diff --git a/src/modules/stream/callable.cpp b/src/modules/stream/callable.cpp
new file mode 100644
index 0000000..b598b05
--- /dev/null
+++ b/src/modules/stream/callable.cpp
@@ -0,0 +1,3 @@
+#include <list>
+#include <core/object.h>
+#include "callable.h"
diff --git a/src/modules/stream/callable.h b/src/modules/stream/callable.h
new file mode 100644
index 0000000..80e0bec
--- /dev/null
+++ b/src/modules/stream/callable.h
@@ -0,0 +1,93 @@
+#ifndef CALLABLE_H_
+#define CALLABLE_H_
+#include <list>
+class _CallableBase {};
+
+template <class T, typename Ret, typename... Args>
+class _Callable : public _CallableBase {
+	T *obj;
+	Ret (T::*method)(Args...);
+
+public:
+	void operator()(Args... args)
+	{
+		(obj->*method)(args...);
+	}
+	_Callable(T *obj, Ret (T::*method)(Args...))
+		: obj(obj)
+		, method(method)
+	{
+	}
+};
+template <typename Ret, typename... Args> class _Signal {
+	std::list<_CallableBase *> callables;
+
+public:
+	class T {};
+	void connect(_CallableBase *callable)
+	{
+		callables.push_front(callable);
+	}
+	void disconnect(_CallableBase *callable)
+	{
+		callables.remove(callable);
+	}
+	void emit(Args... args)
+	{
+		auto e = callables.begin();
+		while (e != callables.end()) {
+			_Callable<T, Ret, Args...> *foo =
+				reinterpret_cast<_Callable<T, Ret, Args...> *>(
+					*e);
+			(*foo)(args...);
+			e++;
+		}
+	}
+};
+#ifdef __TEST
+#include <cstdio>
+class check {
+public:
+	_Signal<void> sig;
+
+public:
+	check()
+	{
+	}
+	void emit()
+	{
+		sig.emit();
+	}
+};
+class cfoo {
+	void handler1()
+	{
+		printf("handler1\n");
+	}
+	void handler2()
+	{
+		printf("handler2\n");
+	}
+
+public:
+	cfoo()
+	{
+		check b;
+		_Callable<cfoo, void> c(this, &cfoo::handler1);
+		_Callable<cfoo, void> d(this, &cfoo::handler2);
+		b.sig.connect(&c);
+		b.sig.connect(&d);
+		b.emit();
+		b.emit();
+		b.sig.disconnect(&c);
+		b.sig.disconnect(&d);
+		b.emit();
+	}
+};
+int main()
+{
+	cfoo c;
+	return 0;
+}
+#endif
+#endif
\ No newline at end of file
diff --git a/src/modules/stream/road_lines_data.h b/src/modules/stream/road_lines_data.h
index 7585d04..336c9ca 100644
--- a/src/modules/stream/road_lines_data.h
+++ b/src/modules/stream/road_lines_data.h
@@ -1,5 +1,6 @@
 #ifndef ROAD_LINES_DATA_H
 #define ROAD_LINES_DATA_H
+#include "callable.h"
 class RoadLinesData {
 	String road_lines_path;
 	uint32_t road_lines_hash(const Vector3 &v);
@@ -7,6 +8,7 @@ class RoadLinesData {
 protected:
 	RoadLinesData();
 	static RoadLinesData *singleton;
+	_Signal<void> lines_updated;
 
 public:
 	struct road_line {
@@ -16,6 +18,7 @@ public:
 		int pattern;
 		int flags;
 		Dictionary metadata;
+		_Signal<void> line_updated;
 	};
 	HashMap<String, struct road_line> lines;
 	static RoadLinesData *get_singleton();