[ESP32] Use nvs iterator to check if key exists (#16885)

* [ESP32] Use nvs iterator to check if key exists

* Comment explaining why no need to release iterator in NULL case

src/platform/ESP32/ESP32Config.cpp

@@ -318,82 +318,19 @@ CHIP_ERROR ESP32Config::ClearConfigValue(Key key)
 
 bool ESP32Config::ConfigValueExists(Key key)
 {
- ScopedNvsHandle handle;
-
- if (handle.Open(key.Namespace, NVS_READONLY) != CHIP_NO_ERROR)
- {
- return false;
- }
-
- // This code is a rather unfortunate consequence of the limitations
- // in the ESP NVS API. As defined, there is no API for determining
- // whether a particular key exists. Furthermore, calling one of the
- // nvs_get_* APIs will result in a ESP_ERR_NVS_NOT_FOUND in the case
- // where the key exists, but the requested data type does not match.
- // (This is true despite the existence of the ESP_ERR_NVS_TYPE_MISMATCH
- // error, which would seem to be the obvious correct response).
- //
- // Thus the solution is to exhaustively check for the key using
- // each possible value type.
- esp_err_t err;
- {
- uint8_t v;
- err = nvs_get_u8(handle, key.Name, &v);
- }
- if (err == ESP_ERR_NVS_NOT_FOUND)
- {
- int8_t v;
- err = nvs_get_i8(handle, key.Name, &v);
- }
- if (err == ESP_ERR_NVS_NOT_FOUND)
- {
- uint16_t v;
- err = nvs_get_u16(handle, key.Name, &v);
- }
- if (err == ESP_ERR_NVS_NOT_FOUND)
+ nvs_iterator_t iterator = nvs_entry_find(NVS_DEFAULT_PART_NAME, key.Namespace, NVS_TYPE_ANY);
+ for (; iterator; iterator = nvs_entry_next(iterator))
  {
- int16_t v;
- err = nvs_get_i16(handle, key.Name, &v);
- }
- if (err == ESP_ERR_NVS_NOT_FOUND)
- {
- uint32_t v;
- err = nvs_get_u32(handle, key.Name, &v);
- }
- if (err == ESP_ERR_NVS_NOT_FOUND)
- {
- int32_t v;
- err = nvs_get_i32(handle, key.Name, &v);
- }
- if (err == ESP_ERR_NVS_NOT_FOUND)
- {
- uint64_t v;
- err = nvs_get_u64(handle, key.Name, &v);
- }
- if (err == ESP_ERR_NVS_NOT_FOUND)
- {
- int64_t v;
- err = nvs_get_i64(handle, key.Name, &v);
- }
- if (err == ESP_ERR_NVS_NOT_FOUND)
- {
- size_t sz;
- err = nvs_get_str(handle, key.Name, NULL, &sz);
- }
- if (err == ESP_ERR_NVS_NOT_FOUND)
- {
- size_t sz;
- err = nvs_get_blob(handle, key.Name, NULL, &sz);
- }
-
- // In the case of blob and string, ESP_ERR_NVS_INVALID_LENGTH means
- // the key exists.
- if (err == ESP_ERR_NVS_INVALID_LENGTH)
- {
- err = ESP_OK;
+ nvs_entry_info_t info;
+ nvs_entry_info(iterator, &info);
+ if (strcmp(info.key, key.Name) == 0)
+ {
+ nvs_release_iterator(iterator);
+ return true;
+ }
  }
-
- return err == ESP_OK;
+ // if nvs_entry_find() or nvs_entry_next() returns NULL, then no need to release the iterator.
+ return false;
 }
 
 CHIP_ERROR ESP32Config::EnsureNamespace(const char * ns)