tlbmc/hal/led/led_gpio.h

#ifndef THIRD_PARTY_MILOTIC_EXTERNAL_CC_TLBMC_HAL_LED_LED_GPIO_H_
#define THIRD_PARTY_MILOTIC_EXTERNAL_CC_TLBMC_HAL_LED_LED_GPIO_H_

#include <memory>
#include <optional>
#include <string>

#include "absl/base/thread_annotations.h"
#include "absl/status/status.h"
#include "absl/status/statusor.h"
#include "tlbmc/collector/gpio_collector.h"
#include "led_config.pb.h"
#include "tlbmc/hal/led/led.h"
#include "tlbmc/scheduler/scheduler.h"

namespace milotic_tlbmc {

// LED backed by a GPIO line managed by GpioCollector.
//
// Translates high-level LedBehavior into GpioCollector calls:
//   - LED_STATE_OFF:   gpio_collector.SetGpio(gpio_name, false)
//   - LED_STATE_ON:    gpio_collector.SetGpio(gpio_name, true)
//   - LED_STATE_BLINK: software blinking via TaskScheduler, toggling the GPIO
//                      line using gpio_collector.SetGpio(gpio_name, level).
//
// This class is thread-safe.
class GpioLed final : public Led {
 public:
  static absl::StatusOr<std::unique_ptr<GpioLed>> Create(
      const LedConfig& config, GpioCollector& gpio_collector,
      TaskScheduler* task_scheduler);

  ~GpioLed() override;

 protected:
  absl::Status SetBehaviorImpl(const LedBehavior& behavior)
      ABSL_EXCLUSIVE_LOCKS_REQUIRED(mutex_) override;
  absl::StatusOr<LedBehavior> GetBehaviorImpl() const
      ABSL_SHARED_LOCKS_REQUIRED(mutex_) override;

 private:
  GpioLed(const LedConfig& config, GpioCollector& gpio_collector,
          TaskScheduler* task_scheduler)
      : Led(config),
        gpio_collector_(gpio_collector),
        gpio_name_(config.output().gpio_name()),
        task_scheduler_(task_scheduler) {}

 private:
  void StopBlinking() ABSL_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
  absl::Status StartBlinking(const BlinkConfig& blink_config)
      ABSL_EXCLUSIVE_LOCKS_REQUIRED(mutex_);

  void BlinkPeriodicStep() ABSL_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
  void BlinkOneShotStep() ABSL_EXCLUSIVE_LOCKS_REQUIRED(mutex_);

  GpioCollector& gpio_collector_;
  const std::string gpio_name_;
  TaskScheduler* const task_scheduler_;

  int task_id_ ABSL_GUARDED_BY(mutex_) = -1;
  bool current_level_ ABSL_GUARDED_BY(mutex_) = false;
  std::optional<LedBehavior> behavior_ ABSL_GUARDED_BY(mutex_);
};

}  // namespace milotic_tlbmc

#endif  // THIRD_PARTY_MILOTIC_EXTERNAL_CC_TLBMC_HAL_LED_LED_GPIO_H_