refactor(rfkill): poll rfkill events from Glib main loop

Open rfkill device only once per module.
Remove rfkill threads and use `Glib::signal_io` as a more efficient way
to poll the rfkill device.
Handle runtime errors from rfkill and stop polling of the device instead
of crashing waybar.

include/modules/bluetooth.hpp

@@ -1,11 +1,11 @@
 #pragma once
 
-#include <fmt/format.h>
-#include "ALabel.hpp"
-
 #include <fmt/chrono.h>
-#include "util/sleeper_thread.hpp"
+#include <fmt/format.h>
+
+#include "ALabel.hpp"
 #include "util/rfkill.hpp"
+#include "util/sleeper_thread.hpp"
 
 namespace waybar::modules {
 
@@ -16,11 +16,9 @@ class Bluetooth : public ALabel {
   auto update() -> void;
 
  private:
-  std::string           status_;
-  util::SleeperThread 	thread_;
-  util::SleeperThread 	intervall_thread_;
-
-  util::Rfkill rfkill_;
+  std::string         status_;
+  util::SleeperThread thread_;
+  util::Rfkill        rfkill_;
 };
 
 }  // namespace waybar::modules

include/modules/network.hpp

@@ -75,8 +75,6 @@ class Network : public ALabel {
   util::SleeperThread thread_;
   util::SleeperThread thread_timer_;
 #ifdef WANT_RFKILL
-  util::SleeperThread thread_rfkill_;
-
   util::Rfkill rfkill_;
 #endif
 };

include/util/rfkill.hpp

@@ -1,19 +1,26 @@
 #pragma once
 
+#include <glibmm/iochannel.h>
 #include <linux/rfkill.h>
+#include <sigc++/signal.h>
+#include <sigc++/trackable.h>
 
 namespace waybar::util {
 
-class Rfkill {
+class Rfkill : public sigc::trackable {
  public:
   Rfkill(enum rfkill_type rfkill_type);
-  ~Rfkill() = default;
-  void waitForEvent();
+  ~Rfkill();
   bool getState() const;
 
+  sigc::signal<void(struct rfkill_event&)> on_update;
+
  private:
   enum rfkill_type rfkill_type_;
-  int              state_ = 0;
+  bool             state_ = false;
+  int              fd_ = -1;
+
+  bool on_event(Glib::IOCondition cond);
 };
 
 }  // namespace waybar::util