115 lines
4.0 KiB
C
115 lines
4.0 KiB
C
/*
|
|
* Copyright (c) 2020 Huawei Device Co., Ltd.
|
|
* Licensed under the Apache License, Version 2.0 (the "License");
|
|
* you may not use this file except in compliance with the License.
|
|
* You may obtain a copy of the License at
|
|
*
|
|
* http://www.apache.org/licenses/LICENSE-2.0
|
|
*
|
|
* Unless required by applicable law or agreed to in writing, software
|
|
* distributed under the License is distributed on an "AS IS" BASIS,
|
|
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
* See the License for the specific language governing permissions and
|
|
* limitations under the License.
|
|
*/
|
|
|
|
/**
|
|
* @addtogroup kv_store
|
|
* @{
|
|
*
|
|
* @brief Provides functions for obtaining, setting, and deleting a key-value pair.
|
|
*
|
|
*
|
|
* Key-value pairs can be permanently stored in the file system. \n
|
|
* If {@link FEATURE_KV_CACHE} is enabled, key-value pairs can be stored in the cache. \n
|
|
* For details about cache specifications, see {@link MAX_CACHE_SIZE}. \n
|
|
* For details about the number of key-value pairs that can be stored in an application, see {@link MAX_KV_SUM}. \n
|
|
*
|
|
* @since 1.0
|
|
* @version 1.0
|
|
*/
|
|
|
|
/**
|
|
* @file kv_store.h
|
|
*
|
|
* @brief Provides functions for obtaining, setting, and deleting a key-value pair.
|
|
*
|
|
* @since 1.0
|
|
* @version 1.0
|
|
*/
|
|
|
|
#ifndef KV_STORE_API_H
|
|
#define KV_STORE_API_H
|
|
|
|
#include "utils_config.h"
|
|
|
|
#ifdef __cplusplus
|
|
#if __cplusplus
|
|
extern "C" {
|
|
#endif
|
|
#endif /* __cplusplus */
|
|
|
|
/**
|
|
* @brief Obtains the value matching a specified key from the file system or cache.
|
|
*
|
|
* @param key Indicates the key to be indexed. It allows only lowercase letters, digits, underscores (_), and dots (.).
|
|
* Its length cannot exceed 32 bytes (including the end-of-text character in the string).
|
|
* @param value Indicates the buffer for storing the value that matches the key. This is an output parameter.
|
|
* @param len Indicates the size of the value space in the buffer.
|
|
* @return Returns the length of the value if the operation is successful;
|
|
* returns <b>-9</b> if a parameter is incorrect; returns <b>-1</b> in other scenarios;
|
|
* returns <b>0</b> if the value is obtained from the cache.
|
|
* @since 1.0.
|
|
* @version 1.0.
|
|
*/
|
|
int UtilsGetValue(const char* key, char* value, unsigned int len);
|
|
|
|
/**
|
|
* @brief Adds or updates the value matching a specified key in the file system or cache.
|
|
*
|
|
* @param key Indicates the key whose value is to be added or updated.
|
|
* It allows only lowercase letters, digits, underscores (_), and dots (.).
|
|
* Its length cannot exceed 32 bytes (including the end-of-text character in the string).
|
|
* @param value Indicates the value to be added or updated.
|
|
* Its length cannot exceed 128 bytes (including the end-of-text character in the string).
|
|
* @return Returns <b>0</b> if the operation is successful; returns <b>-9</b> if a parameter is incorrect;
|
|
* returns <b>-1</b> in other scenarios.
|
|
* @since 1.0.
|
|
* @version 1.0.
|
|
*/
|
|
int UtilsSetValue(const char* key, const char* value);
|
|
|
|
/**
|
|
* @brief Deletes the value matching a specified key from the file system or cache.
|
|
*
|
|
* @param key Indicates the key whose value is to be deleted.
|
|
* It allows only lowercase letters, digits, underscores (_), and dots (.).
|
|
* Its length cannot exceed 32 bytes (including the end-of-text character in the string).
|
|
* @return Returns <b>0</b> if the operation is successful; returns <b>-9</b> if a parameter is incorrect;
|
|
* returns <b>-1</b> in other scenarios.
|
|
* @since 1.0.
|
|
* @version 1.0.
|
|
*/
|
|
int UtilsDeleteValue(const char* key);
|
|
|
|
#ifdef FEATURE_KV_CACHE
|
|
|
|
/**
|
|
* @brief Clears all key-value pairs from the cache.
|
|
*
|
|
* @attention This function is available only if {@link FEATURE_KV_CACHE} is enabled.
|
|
* @return Returns <b>0</b> if the operation is successful; returns <b>-1</b> otherwise.
|
|
* @since 1.0.
|
|
* @version 1.0.
|
|
*/
|
|
int ClearKVCache(void);
|
|
#endif
|
|
|
|
#ifdef __cplusplus
|
|
#if __cplusplus
|
|
}
|
|
#endif
|
|
#endif /* __cplusplus */
|
|
|
|
#endif // KV_STORE_API_H
|
|
/** @} */ |