refactor: move backlight backend out of backlight module

include/modules/backlight.hpp

@@ -1,14 +1,14 @@
 #pragma once
 
+#include <memory>
 #include <optional>
 #include <string>
 #include <string_view>
 #include <vector>
 
 #include "ALabel.hpp"
-#include "giomm/dbusproxy.h"
+#include "util/backlight_backend.hpp"
 #include "util/json.hpp"
-#include "util/sleeper_thread.hpp"
 
 struct udev;
 struct udev_device;
@@ -16,54 +16,17 @@ struct udev_device;
 namespace waybar::modules {
 
 class Backlight : public ALabel {
-  class BacklightDev {
-   public:
-    BacklightDev() = default;
-    BacklightDev(std::string name, int actual, int max, bool powered);
-    std::string_view 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 BacklightDev &lhs, const BacklightDev &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;
-  };
-
  public:
   Backlight(const std::string &, const Json::Value &);
-  virtual ~Backlight();
+  virtual ~Backlight() = default;
   auto update() -> void override;
 
- private:
-  template <class ForwardIt>
-  static const BacklightDev *best_device(ForwardIt first, ForwardIt last, std::string_view);
-  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 handleScroll(GdkEventScroll *e) override;
 
   const std::string preferred_device_;
-  static constexpr int EPOLL_MAX_EVENTS = 16;
 
-  std::optional<BacklightDev> previous_best_;
   std::string previous_format_;
 
-  std::mutex udev_thread_mutex_;
-  std::vector<BacklightDev> devices_;
-  // thread must destruct before shared data
-  util::SleeperThread udev_thread_;
-
-  Glib::RefPtr<Gio::DBus::Proxy> login_proxy_;
+  util::BacklightBackend backend;
 };
 }  // namespace waybar::modules

include/util/audio_backend.hpp

@@ -10,12 +10,10 @@
 #include <memory>
 #include <string>
 
+#include "util/backend_common.hpp"
+
 namespace waybar::util {
 
-enum class ChangeType : char { Increase, Decrease };
-
-void noop();
-
 class AudioBackend {
  private:
   static void subscribeCb(pa_context*, pa_subscription_event_type_t, uint32_t, void*);
@@ -50,7 +48,7 @@ class AudioBackend {
 
   std::vector<std::string> ignored_sinks_;
 
-  std::function<void()> on_updated_cb_ = noop;
+  std::function<void()> on_updated_cb_ = NOOP;
 
   /* Hack to keep constructor inaccessible but still public.
    * This is required to be able to use std::make_shared.
@@ -61,7 +59,7 @@ class AudioBackend {
   struct private_constructor_tag {};
 
  public:
-  static std::shared_ptr<AudioBackend> getInstance(std::function<void()> on_updated_cb = noop);
+  static std::shared_ptr<AudioBackend> getInstance(std::function<void()> on_updated_cb = NOOP);
 
   AudioBackend(std::function<void()> on_updated_cb, private_constructor_tag tag);
   ~AudioBackend();

include/util/backend_common.hpp

@@ -0,0 +1,10 @@
+#pragma once
+
+#include "AModule.hpp"
+
+namespace waybar::util {
+
+const static auto NOOP = []() {};
+enum class ChangeType : char { Increase, Decrease };
+
+}  // namespace waybar::util

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