preferences.h

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#pragma once
#ifdef USE_ESP32
 
#include "esphome/core/preference_backend.h"
#include <soc/soc_caps.h>
 
// RTC-backed preference storage is compiled in only when a config option actually selects it
// (USE_ESP32_RTC_PREFERENCES, emitted during code generation) and the variant has RTC memory
// (SOC_RTC_MEM_SUPPORTED; the ESP32-C2 and -C61 have none). Otherwise in_flash=false falls
// back to NVS and no RTC memory is reserved.
#if defined(USE_ESP32_RTC_PREFERENCES) && SOC_RTC_MEM_SUPPORTED
#define USE_ESP32_RTC_PREFERENCES_STORAGE
#endif
 
namespace esphome::esp32 {
 
struct NVSData;
 
class ESP32Preferences final : public PreferencesMixin<ESP32Preferences> {
 public:
  using PreferencesMixin<ESP32Preferences>::make_preference;
  void open();
  ESPPreferenceObject make_preference(size_t length, uint32_t type, bool in_flash);
  // Two-argument form defaults to NVS (flash) storage, preserving historic ESP32 behavior.
  ESPPreferenceObject make_preference(size_t length, uint32_t type);
  bool load_from_key(uint32_t type, uint8_t *data, size_t len);
  bool sync();
  bool reset();
 
  uint32_t nvs_handle;
 
 protected:
  ESP32PreferenceBackend make_backend_(uint32_t type) const;
  bool is_changed_(uint32_t nvs_handle, const NVSData &to_save, const char *key_str);
 
#ifdef USE_ESP32_RTC_PREFERENCES_STORAGE
  // RTC-backed storage (in_flash=false).
  ESPPreferenceObject make_rtc_preference_(size_t length, uint32_t type);
  // Next free word offset in the RTC storage region (bump allocated in make_preference order).
  uint16_t current_rtc_offset_{0};
#endif
};
 
void setup_preferences();
 
}  // namespace esphome::esp32
 
DECLARE_PREFERENCE_ALIASES(esphome::esp32::ESP32Preferences)
 
#endif  // USE_ESP32