refactor: move backlight backend out of backlight module

include/util/backlight_backend.hpp

@@ -0,0 +1,91 @@
+#pragma once
+
+#include <libudev.h>
+#include <spdlog/spdlog.h>
+
+#include <chrono>
+#include <mutex>
+#include <optional>
+#include <string>
+#include <string_view>
+#include <vector>
+
+#include "giomm/dbusproxy.h"
+#include "util/backend_common.hpp"
+#include "util/sleeper_thread.hpp"
+
+#define GET_BEST_DEVICE(varname, backend, preferred_device)          \
+  decltype((backend).devices_) __devices;                            \
+  {                                                                  \
+    std::scoped_lock<std::mutex> lock((backend).udev_thread_mutex_); \
+    __devices = (backend).devices_;                                  \
+  }                                                                  \
+  auto varname = (backend).best_device(__devices.cbegin(), __devices.cend(), preferred_device);
+
+namespace waybar::util {
+
+class BacklightDevice {
+ public:
+  BacklightDevice() = default;
+  BacklightDevice(std::string name, int actual, int max, bool powered);
+
+  std::string name() const;
+  int get_actual() const;
+  void set_actual(int actual);
+  int get_max() const;
+  void set_max(int max);
+  bool get_powered() const;
+  void set_powered(bool powered);
+  friend inline bool operator==(const BacklightDevice &lhs, const BacklightDevice &rhs) {
+    return lhs.name_ == rhs.name_ && lhs.actual_ == rhs.actual_ && lhs.max_ == rhs.max_;
+  }
+
+ private:
+  std::string name_;
+  int actual_ = 1;
+  int max_ = 1;
+  bool powered_ = true;
+};
+
+class BacklightBackend {
+ public:
+  BacklightBackend(std::chrono::milliseconds interval, std::function<void()> on_updated_cb = NOOP);
+
+  // const inline BacklightDevice *get_best_device(std::string_view preferred_device);
+  const BacklightDevice *get_previous_best_device();
+
+  void set_previous_best_device(const BacklightDevice *device);
+
+  void set_brightness(std::string preferred_device, int brightness);
+  void set_brightness(std::string preferred_device, ChangeType change_type, double step);
+
+  template <class ForwardIt, class Inserter>
+  static void upsert_device(ForwardIt first, ForwardIt last, Inserter inserter, udev_device *dev);
+
+  template <class ForwardIt, class Inserter>
+  static void enumerate_devices(ForwardIt first, ForwardIt last, Inserter inserter, udev *udev);
+
+  bool is_login_proxy_initialized() const { return static_cast<bool>(login_proxy_); }
+
+  template <class ForwardIt>
+  static const BacklightDevice *best_device(ForwardIt first, ForwardIt last, std::string_view);
+
+  std::vector<BacklightDevice> devices_;
+  std::mutex udev_thread_mutex_;
+
+ private:
+  void set_brightness_internal(std::string device_name, int brightness, int max_brightness);
+
+  std::function<void()> on_updated_cb_;
+  std::chrono::milliseconds polling_interval_;
+
+  std::optional<BacklightDevice> previous_best_;
+  // thread must destruct before shared data
+  util::SleeperThread udev_thread_;
+
+  Glib::RefPtr<Gio::DBus::Proxy> login_proxy_;
+
+  static constexpr int EPOLL_MAX_EVENTS = 16;
+};
+
+}  // namespace waybar::util