鸿蒙0基础学习【授权持久化(C/C++)】文件基础服务

场景介绍

支持设备PC/2in1

应用通过Picker获取临时授权，临时授权在应用退出后或者设备重启后会清除。如果应用重启或者设备重启后需要直接访问之前已访问过的文件，则对文件进行[持久化授权]。FileShare提供了支持基于uri的文件及目录授于持久化权限、权限激活、权限查询等方法。

接口说明

支持设备PC/2in1

接口名称 描述 OH_FileShare_PersistPermission(const FileShare_PolicyInfo *policies, unsigned int policyNum, FileShare_PolicyErrorResult **result, unsigned int *resultNum) 对所选择的多个文件或目录uri持久化授权。 OH_FileShare_RevokePermission(const FileShare_PolicyInfo *policies, unsigned int policyNum, FileShare_PolicyErrorResult **result, unsigned int *resultNum) 对所选择的多个文件或目录uri取消持久化授权。 OH_FileShare_ActivatePermission(const FileShare_PolicyInfo *policies, unsigned int policyNum, FileShare_PolicyErrorResult **result, unsigned int *resultNum) 使能多个已经永久授权过的文件或目录uri。 OH_FileShare_DeactivatePermission(const FileShare_PolicyInfo *policies, unsigned int policyNum, FileShare_PolicyErrorResult **result, unsigned int *resultNum) 取消使能授权过的多个文件或目录uri。 OH_FileShare_CheckPersistentPermission(const FileShare_PolicyInfo *policies, unsigned int policyNum, bool **result, unsigned int *resultNum) 校验所选择的多个文件或目录uri的持久化权限结果。 OH_FileShare_ReleasePolicyErrorResult(FileShare_PolicyErrorResult *errorResult, unsigned int resultNum) 释放FileShare_PolicyErrorResult内存。

约束与限制

支持设备PC/2in1

• 使用文件分享的相关接口，需确认设备具有以下系统能力：SystemCapability.FileManagement.AppFileService.FolderAuthorization。
• 在调用文件分享的相关接口前，需要申请权限：“ohos.permission.FILE_ACCESS_PERSIST”

开发步骤

支持设备PC/2in1

以下步骤描述了如何使用FileShare提供的Native API接口。

添加动态链接库

CMakeLists.txt中添加以下lib。

target_link_libraries(sample PUBLIC libohfileshare.so)

头文件

#include #include 

1. 创建FileShare_PolicyInfo实例,调用OH_FileShare_PersistPermission接口，设置uri的持久化授权，接口入参policyNum最大上限为500。

static const uint32_t POLICY_NUM = 2;char strTestPath1[] = \"file://com.example.fileshare/data/storage/el2/base/files/test1.txt\";char strTestPath2[] = \"file://com.example.fileshare/data/storage/el2/base/files/test2.txt\";FileShare_PolicyInfo policy[POLICY_NUM] = { {strTestPath1, static_cast(strlen(strTestPath1)), FileShare_OperationMode::READ_MODE}, {strTestPath2, static_cast(strlen(strTestPath2)), FileShare_OperationMode::WRITE_MODE}};FileShare_PolicyErrorResult* result = nullptr;uint32_t resultNum = 0;auto ret = OH_FileShare_PersistPermission(policy, POLICY_NUM, &result, &resultNum);if (ret != ERR_OK) { if (ret == ERR_EPERM && result != nullptr) { for(uint32_t i = 0; i < resultNum; i++) { std::cout << \"error uri: \" << result[i].uri << std::endl; std::cout << \"error code: \" << result[i].code << std::endl; std::cout << \"error message: \" << result[i].message << std::endl; } }}OH_FileShare_ReleasePolicyErrorResult(result, resultNum);

1. 调用OH_FileShare_ActivatePermission接口，激活启用已授权过的uri，接口入参policyNum最大上限为500。

auto ret = OH_FileShare_ActivatePermission(policy, POLICY_NUM, &result, &resultNum);if (ret != ERR_OK) { if (ret == ERR_EPERM && result != nullptr) { for(uint32_t i = 0; i < resultNum; i++) { std::cout << \"error uri: \" << result[i].uri << std::endl; std::cout << \"error code: \" << result[i].code << std::endl; std::cout << \"error message: \" << result[i].message << std::endl; } }}OH_FileShare_ReleasePolicyErrorResult(result, resultNum);

1. 调用OH_FileShare_DeactivatePermission接口，停止已启用授权过uri的访问权限，接口入参policyNum最大上限为500。

auto ret = OH_FileShare_DeactivatePermission(policy, POLICY_NUM, &result, &resultNum);if (ret != ERR_OK) { if (ret == ERR_EPERM && result != nullptr) { for(uint32_t i = 0; i < resultNum; i++) { std::cout << \"error uri: \" << result[i].uri << std::endl; std::cout << \"error code: \" << result[i].code << std::endl; std::cout << \"error message: \" << result[i].message << std::endl; } }}OH_FileShare_ReleasePolicyErrorResult(result, resultNum);

1. 调用OH_FileShare_RevokePermission接口，撤销已经授权的uri持久化权限，接口入参policyNum最大上限为500。

auto ret = OH_FileShare_RevokePermission(policy, POLICY_NUM, &result, &resultNum);if (ret != ERR_OK) { if (ret == ERR_EPERM && result != nullptr) { for(uint32_t i = 0; i < resultNum; i++) { std::cout << \"error uri: \" << result[i].uri << std::endl; std::cout << \"error code: \" << result[i].code << std::endl; std::cout << \"error message: \" << result[i].message << std::endl; } }}OH_FileShare_ReleasePolicyErrorResult(result, resultNum);

1. 调用OH_FileShare_CheckPersistentPermission接口，检查uri持久化权限，接口入参policyNum最大上限为500。

bool *result = nullptr;auto ret = OH_FileShare_CheckPersistentPermission(policy, POLICY_NUM, &result, &resultNum);if (result != nullptr && resultNum > 0) { for(uint32_t i = 0; i < resultNum && resultNum <= POLICY_NUM; i++) { std::cout << \"uri: \" << policy[i].uri << std::endl; std::cout << \"result: \" << result[i] << std::endl; }}std::cout << \"retCode: \" << ret << std::endl;free(result);

更多内容：

在↓