# 公共基础库开发指导 - [接口说明](#section1633115419401) - [开发步骤](#section17450172710292) - [LiteOS-A内核\(Hi3516、Hi3518平台\)KV存储的native应用开发步骤：](#section258354119295) - [Dump系统属性在LiteOS-M内核平台使用指南：](#section9179161863014) - [Dump系统属性在LiteOS-A内核平台使用指南：](#section3179121853017) ## 接口说明 **表 1** 文件操作接口说明

接口名

描述

int UtilsFileOpen(const char* path, int oflag, int mode)

打开或创建文件

int UtilsFileClose(int fd)

关闭文件

int UtilsFileRead(int fd, char *buf, unsigned int len)

读取特定长度的文件数据

int UtilsFileWrite(int fd, const char *buf, unsigned int len)

向文件写入特定大小的数据

int UtilsFileDelete(const char *path)

删除指定文件

int UtilsFileStat(const char *path, unsigned int *fileSize)

获取文件大小

int UtilsFileSeek(int fd, int offset, unsigned int whence)

重新定位文件读/写偏移量

int UtilsFileCopy(const char* src, const char* dest)

将源文件复制一份并存储到目标文件

int UtilsFileMove(const char* src, const char* dest)

将源文件移动到指定目标文件
文件操作使用示例： ``` // open && write char fileName[] = "testfile"; static const char def[] = "utils_file_operation implement."; int fd = UtilsFileOpen(fileName, O_RDWR_FS | O_CREAT_FS | O_TRUNC_FS, 0); printf("file handle = %d\n", fd); int ret = UtilsFileWrite(fd, def, strlen(def)); printf("write ret = %d\n", ret); // seek ret = UtilsFileSeek(fd, 5, SEEK_SET_FS); printf("lseek ret = %d\n", ret); // read && close char buf[64] = {0}; int readLen = UtilsFileRead(fd, buf, 64); ret = UtilsFileClose(fd); printf("read len = %d : buf = %s\n", readLen, buf); // stat int fileLen = 0; ret = UtilsFileStat(fileName, &fileLen); printf("file size = %d\n", fileLen); // delete ret = UtilsFileDelete(fileName); printf("delete ret = %d\n", ret); ``` **表 2** KV存储接口说明

接口名

描述

int UtilsGetValue(const char* key, char* value, unsigned int len)

提供给上层应用根据key获取对应数据项

int UtilsSetValue(const char* key, const char* value)

提供给上层应用用于存储/更新key对应数据项

int UtilsDeleteValue(const char* key)

提供给上层应用删除key对应数据项
KV存储使用示例： ``` // set char key[] = "rw.sys.version_100"; char value[] = "Hello kv operation implement!"; int ret = UtilsSetValue(key, value); printf("UtilsSetValue set ret = %d\n", ret); // get char temp[128] = {0}; ret = UtilsGetValue(key, temp, 128); printf("UtilsGetValue get ret = %d, temp = %s\n", ret, temp); // delete ret = UtilsDeleteValue(key); printf("UtilsDeleteValue delete ret = %d\n", ret); ```
## 开发步骤 ### LiteOS-A内核\(Hi3516、Hi3518平台\)KV存储的native应用开发步骤： 1. 基于AbilityKit开发KV存储的native应用。 - 基于KV存储提供的接口编写用户程序，并编译出so（libLauncher.so）文件。 ``` // set char key[] = "rw.sys.version_100"; char value[] = "Hello kv operation implement!"; int ret = UtilsSetValue(key, value); printf("UtilsSetValue set ret = %d\n", ret); // get char temp[128] = {0}; ret = UtilsGetValue(key, temp, 128); printf("UtilsGetValue get ret = %d, temp = %s\n", ret, temp); // delete ret = UtilsDeleteValue(key); printf("UtilsDeleteValue delete ret = %d\n", ret); ``` - 编写config.json文件，内容如下： ``` { "app": { "bundleName": "com.huawei.launcher", "vendor": "huawei", "version": { "code": 1, "name": "1.0" } }, "deviceConfig": { "default": { "reqSdk": { "compatible": "zsdk 1.0.0", "target": "zsdk 1.0.1" }, "keepAlive": false }, "smartCamera": { "reqSdk": { "compatible": "zsdk 1.0.0", "target": "zsdk 1.0.1" }, "keepAlive": false } }, "module": { "package": "com.huawei.launcher", "name": ".MyHarmonyAbilityPackage", "deviceType": [ "phone", "tv","tablet", "pc","car","smartWatch","sportsWatch","smartCamera" ], "distro": { "deliveryWithInstall": true, "moduleName": "Launcher", "moduleType": "entry" }, "abilities": [{ "name": "MainAbility", "icon": "res/drawable/phone.png", "label": "test app 1", "launchType": "standard", "type": "page" }, { "name": "SecondAbility", "icon": "res/drawable/phone.png", "label": "test app 2", "launchType": "standard", "type": "page" }, { "name": "ServiceAbility", "icon": "res/drawable/phone.png", "label": "test app 2", "launchType": "standard", "type": "service" } ] } } ``` - 生成hap包。 - 按照如下目录结构存放文件，res/drawable下面放置资源文件： ![](figure/unnaming.png) - 将上述文件打包生成zip包，修改后缀为.hap，例如Launcher.hap 2. 连接单板，通过串口向单板发送安装KV存储native应用的命令。 ``` ./nfs/dev_tools/bin/bm install -p /nfs/Launcher.hap ``` 3. 通过串口向单板发送运行KV存储native应用的命令。 ``` ./nfs/dev_tools/bin/aa start -p com.huawei.launcher -n ServiceAbility ``` ### Dump系统属性在LiteOS-M内核平台使用指南： 1. 连接单板，通过串口向单板发送AT+SYSPARA命令。 ``` AT+SYSPARA ``` **图 1** LiteOS-M平台dump系统属性输出 ![](figure/LiteOS-M平台dump系统属性输出.png "LiteOS-M平台dump系统属性输出") ### Dump系统属性在LiteOS-A内核平台使用指南： 1. 连接单板，运行bin路径下的os\_dump加参数--help，查看os\_dump使用指导。 ``` ./bin/os_dump --help ``` 2. os\_dump加参数-l，查看当前系统有哪些模块支持获取属性。 ``` ./bin/os_dump -l ``` 3. os\_dump加参数syspara，查看当前系统属性 ``` ./bin/os_dump syspara ``` **图 2** LiteOS-A平台dump系统属性输出 ![](figure/LiteOS-A平台dump系统属性输出.png "LiteOS-A平台dump系统属性输出")