add kv_store sample for bearpi_hm_nano

Signed-off-by: Neil Chen <jingsi.chen@petalmail.com>

bearpi_hm_nano/app/BUILD.gn

@@ -50,5 +50,6 @@ lite_component("app") {
     # "D12_iot_cloud_oc_gps:cloud_oc_gps",
 
     # "Z1_basic_flash_ylc:flash_example",
+    # "Z2_basic_kv_store:kv_store_example",
   ]
 }

bearpi_hm_nano/app/Z2_basic_kv_store/BUILD.gn

@@ -0,0 +1,21 @@
+# Copyright (c) 2020 Nanjing Xiaoxiongpai Intelligent Technology 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.
+
+static_library("kv_store_example") {
+  sources = [ "kv_store_example.c" ]
+
+  include_dirs = [
+    "//base/iothardware/peripheral/interfaces/inner_api",
+    "//utils/native/lite/include",
+  ]
+}

bearpi_hm_nano/app/Z2_basic_kv_store/README.md

@@ -0,0 +1,82 @@
+# 公共基础子系统开发 —— kv存储（基于BearPi-HM_Nano开发板）
+本示例将演示如何使用kv存储相关的API
+
+## kv_store API分析
+本示例主要使用了以下API完成kv存储相关的验证。
+
+### UtilsGetValue()
+```c
+int UtilsGetValue(const char* key, char* value, unsigned int len);
+```
+**描述：**
+
+从文件系统或cache中获取键 key 对应的值
+
+**参数：**
+
+|名字|描述|
+|:--|:------|
+| key | 键  |
+| value | 指向存储键所对应的值所在的地址 |
+| len | 存放value的存储区大小 |
+
+### UtilsSetValue()
+```c
+int UtilsSetValue(const char* key, const char* value);
+```
+**描述：**
+
+新增或更新存储在文件系统或cache中的键 key 所对应的值
+
+**参数：**
+
+|名字|描述|
+|:--|:------|
+| key | 键  |
+| value | 待新增或更新的值 |
+
+### UtilsDeleteValue()
+```c
+int UtilsDeleteValue(const char* key);
+```
+**描述：**
+
+删除存储在文件系统或cache中的键 key 所对应的值
+
+**参数：**
+
+|名字|描述|
+|:--|:------|
+| key | 键  |
+
+
+## 编译调试
+
+### 修改 BUILD.gn 文件
+
+修改 `device\board\bearpi\bearpi_hm_nano\app` 路径下的 BUILD.gn 文件，指定 `Z2_basic_kv_store` 参与编译。
+
+```r
+    # "D11_iot_cloud_oc_agriculture:cloud_oc_agriculture",
+    # "D12_iot_cloud_oc_gps:cloud_oc_gps",
+
+    # "Z1_basic_flash_ylc:flash_example",
+    "Z2_basic_kv_store:kv_store_example",
+```
+
+### 运行结果
+
+示例代码编译烧录后，按下开发板的RESET按键，通过串口助手可以看到kv操作过程。
+
+```sh
+hiview init success.
+[PARAM][param_service.c:125]ParamServiceTask start
+get value failed!
+===== key: user, value:  =====
+===== key: user, value: Zhang San =====
+delete key-value for user success.
+get value failed!
+===== key: user, value:  =====
+
+```
+

bearpi_hm_nano/app/Z2_basic_kv_store/kv_store_example.c

@@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2020 Nanjing Xiaoxiongpai Intelligent Technology 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.
+ */
+
+#include <stdio.h>
+
+#include "ohos_init.h"
+#include "cmsis_os2.h"
+#include "kv_store.h"
+
+#define BOOT_WAIT_TIME 200
+
+static void ShowValue(const char* key)
+{
+    if (!key) {
+        return;
+    }
+
+    char buf[512] = {0};
+
+    if (UtilsGetValue(key, buf, sizeof(buf)-1) < 0) {
+        printf("get value failed!\n");
+    }
+    printf("===== key: %s, value: %s =====\n", key, buf);
+}
+
+static void KvStoreExampleEntry(void)
+{
+    const char* usernameKey = "user";
+    const char* usernameValue = "Zhang San";
+
+    // wait a while for checking log easily
+    osDelay(BOOT_WAIT_TIME);
+
+    // 1. get value failed if no key-value exist
+    ShowValue(usernameKey);
+
+    // 2. save key-value
+    if (UtilsSetValue(usernameKey, usernameValue) < 0) {
+        printf("set username value failed!\n");
+    }
+
+    // 3. get value success if key-value exist
+    ShowValue(usernameKey);
+
+    // 4. get value failed after key-value deleted
+    if (UtilsDeleteValue(usernameKey) < 0) {
+        printf("delete key-value for %s failed!\n", usernameKey);
+    } else {
+        printf("delete key-value for %s success.\n", usernameKey);
+    }
+
+    ShowValue(usernameKey);
+}
+
+APP_FEATURE_INIT(KvStoreExampleEntry);