preference_backend.h

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#pragma once
 
#include <cstdint>
 
#include "esphome/core/defines.h"
#include "esphome/core/helpers.h"
 
// Include the concrete preference backend for the active platform.
// Each header defines its backend class, forward-declares its manager class,
// declares get_preferences(), and provides the PreferenceBackend alias.
#ifdef USE_ESP32
#include "esphome/components/esp32/preference_backend.h"
#elif defined(USE_ESP8266)
#include "esphome/components/esp8266/preference_backend.h"
#elif defined(USE_RP2040)
#include "esphome/components/rp2040/preference_backend.h"
#elif defined(USE_LIBRETINY)
#include "esphome/components/libretiny/preference_backend.h"
#elif defined(USE_HOST)
#include "esphome/components/host/preference_backend.h"
#elif defined(USE_ZEPHYR) && defined(CONFIG_SETTINGS)
#include "esphome/components/zephyr/preference_backend.h"
#endif
 
namespace esphome {
 
#if !defined(USE_ESP32) && !defined(USE_ESP8266) && !defined(USE_RP2040) && !defined(USE_LIBRETINY) && \
    !defined(USE_HOST) && !(defined(USE_ZEPHYR) && defined(CONFIG_SETTINGS))
// Stub for static analysis when no platform is defined.
struct PreferenceBackend {
  bool save(const uint8_t *, size_t) { return false; }
  bool load(uint8_t *, size_t) { return false; }
};
#endif
 
using ESPPreferenceBackend = PreferenceBackend;
 
class ESPPreferenceObject {
 public:
  ESPPreferenceObject() = default;
  explicit ESPPreferenceObject(PreferenceBackend *backend) : backend_(backend) {}
 
  template<typename T> bool save(const T *src) {
    if (this->backend_ == nullptr)
      return false;
    return this->backend_->save(reinterpret_cast<const uint8_t *>(src), sizeof(T));
  }
 
  template<typename T> bool load(T *dest) {
    if (this->backend_ == nullptr)
      return false;
    return this->backend_->load(reinterpret_cast<uint8_t *>(dest), sizeof(T));
  }
 
 protected:
  PreferenceBackend *backend_{nullptr};
};
 
template<typename Derived> class PreferencesMixin {
 public:
  template<typename T, enable_if_t<is_trivially_copyable<T>::value, bool> = true>
  ESPPreferenceObject make_preference(uint32_t type, bool in_flash) {
    return static_cast<Derived *>(this)->make_preference(sizeof(T), type, in_flash);
  }
 
  template<typename T, enable_if_t<is_trivially_copyable<T>::value, bool> = true>
  ESPPreferenceObject make_preference(uint32_t type) {
    return static_cast<Derived *>(this)->make_preference(sizeof(T), type);
  }
};
 
// Macro for platform preferences.h headers to declare the standard aliases.
// Must be used at file scope (outside any namespace).
#define DECLARE_PREFERENCE_ALIASES(platform_class) \
  namespace esphome { \
  using Preferences = platform_class; \
  using ESPPreferences = Preferences; \
  extern ESPPreferences *global_preferences; /* NOLINT(cppcoreguidelines-avoid-non-const-global-variables) */ \
  }
 
}  // namespace esphome