鸿蒙应用框架开发【dlopen加载so库并获取Rawfile资源】 NDK

dlopen加载so库并获取Rawfile资源

介绍

本示例中主要介绍在TaskPool子线程中使用dlopen加载so库，以及如何使用Native Rawfile接口操作Rawfile目录和文件。功能包括文件列表遍历、文件打开、搜索、读取和关闭Rawfile。

效果预览

使用说明

应用界面中展示了Rawfile相关的接口调用，包括获取resources/rawfile目录下的文件、对应的rawfile文件内容、对应rawfile文件的descriptor。其中使用到的功能包括文件列表遍历、文件打开、搜索、读取和关闭Rawfile。

工程目录

├──entry/libs/                             // 需要加载的.so文件
│  ├──arm64-v8a
│  │  └──libentry.so
│  └──x86_64
│     └──libentry.so
├──entry/src/main/cpp/                     // native侧代码
│  ├──include
│  │  └──global_handlers.h                 // 包含全局对象global_handlers的头文件
│  ├──types
│  │  ├──libentry
│  │  │  ├──index.d.ts                     // 接口导出
│  │  │  └──oh-package.json5
│  │  └──libpreloadso
│  │     ├──index.d.ts                     // 接口导出
│  │     └──oh-package.json5
│  ├──CMakeLists.txt                       // 编译脚本
│  ├──global_handlers.cpp                  // 定义全局对象global_handlers
│  ├──preloadso.cpp                        // preload接口
│  └──rawfile_demo.cpp                     // 调用native接口
├──entry/src/main/ets                      // ArkTS侧代码
│  ├──entryability
│  │  └──EntryAbility.ets
│  ├──pages
│  │  └──Index.ets                         // 首页
│  └──utils
│     ├──Constants.ets                     // 预加载的so文件数组
│     ├──Logger.ets                        // 日志工具
│     └──TaskPool.ets                      // TaskPool子线程加载so库
└──entry/src/main/resources                // 应用静态资源目录└──rawfile                              // rawfile资源├──subrawfile│  └──rawfile2.txt├──rawfile.txt└──rawfile1.txt

具体实现

在TaskPool子线程中使用dlopen加载so库，将需要加载的.so文件放到工程文件libs中，在CMakeLists编译脚本中使用target_link_directories命令将包含这些库文件的目录添加到预加载库的链接目录，使用target_link_libraries命令将需要预加载的so库链接到项目中。在Native层的Preload接口中，遍历传入的.so路径数组，使用dlopen函数加载库，并将句柄保存到global_handlers中。暴露Preload接口给ArkTS层使用，使其能够通过preload调用Native层的Preload接口。源码参考：[preloadso.cpp]

/** Copyright (c) 2024 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.*/#include "napi/native_api.h"
#include <dlfcn.h>
#include "global_handlers.h"
#include <hilog/log.h>// Hilog parameters.
const int GLOBAL_RESMGR = 0xFF00;
const char *TAG = "[Preload]";static napi_value Preload(napi_env env, napi_callback_info info) {OH_LOG_Print(LOG_APP, LOG_INFO, GLOBAL_RESMGR, TAG, "Preload init");size_t argc = 1;napi_value args[1] = {nullptr};napi_get_cb_info(env, info, &argc, args, nullptr, nullptr);napi_value result;napi_create_array(env, &result); // Create an array to hold the results.// Args[0] is the SO library path array.napi_valuetype valuetype;napi_typeof(env, args[0], &valuetype);if (valuetype != napi_object) {return nullptr;}// Obtains the length of the input SO library path array.uint32_t arrayLength;napi_get_array_length(env, args[0], &arrayLength);napi_value pathString;// Path for storing the SO library.char path[256];size_t pathLength;OH_LOG_Print(LOG_APP, LOG_INFO, GLOBAL_RESMGR, TAG, "Preload start");for (uint32_t i = 0; i < arrayLength; i++) {napi_get_element(env, args[0], i, &pathString);napi_status status = napi_get_value_string_utf8(env, pathString, path, sizeof(path), &pathLength);if (status != napi_ok) {// Processing the Failure of Obtaining the Path.OH_LOG_Print(LOG_APP, LOG_ERROR, GLOBAL_RESMGR, TAG, " Preload failed");continue;}// Use dlopen to dynamically load the SO library and return the handle of the SO library.void *handler = dlopen(path, RTLD_LAZY);if (handler == nullptr) {// Dlerror throws failure to load library.OH_LOG_Print(LOG_APP, LOG_ERROR, GLOBAL_RESMGR, TAG, " Preload failed");dlerror();continue;}// Save the handles to the global object global_handlers.global_handlers[std::string(path)] = handler;// Add the path of the successfully loaded library to the result array.napi_set_element(env, result, i, pathString);}OH_LOG_Print(LOG_APP, LOG_INFO, GLOBAL_RESMGR, TAG, "Preload finish");// Return the result array that is loaded successfully.return result;
}EXTERN_C_START
static napi_value Init(napi_env env, napi_value exports) {napi_property_descriptor desc[] = {{"preload", nullptr, Preload, nullptr, nullptr, nullptr, napi_default, nullptr}};napi_define_properties(env, exports, sizeof(desc) / sizeof(desc[0]), desc);return exports;
}
EXTERN_C_ENDstatic napi_module demoModule = {.nm_version = 1,.nm_flags = 0,.nm_filename = nullptr,.nm_register_func = Init,.nm_modname = "preloadso",.nm_priv = ((void *)0),.reserved = {0},
};extern "C" __attribute__((constructor)) void RegisterPreloadsoModule(void) { napi_module_register(&demoModule); }

ArkTS层使用TaskPool创建子线程，通过preload接口调用Native侧的Preload接口，实现在TaskPool子线程中加载.so库，导出preloadSOByTaskPool函数。在Ability的onCreate生命周期函数中，调用preloadSOByTaskPool开启子线程，完成so库的预加载。源码参考：[TaskPool.ets]

/** Copyright (c) 2024 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.*/import { taskpool } from '@kit.ArkTS';
import { BusinessError } from '@kit.BasicServicesKit';
import napi from 'libpreloadso.so';
import Constants from './Constants';
import { Logger } from './Logger';/*** Enable the taskpool subthread to preload .so files.* @param* @returns string[] Loaded so library.*/
@Concurrent
function preloadSO(): string[] {return napi.preload(Constants.LIBRARY_PATH_ARRAY);
}/*** Starts the taskpool sub-thread.* @param* @returns Promise<string[]> Asynchronously return the loaded so library.*/
export function preloadSOByTaskPool(): void {// Use new taskpool.Task () to create a task item and input the task execution function and required parameters.const task: taskpool.Task = new taskpool.Task(preloadSO);try {// Use taskpool.execute to put the function to be executed into the internal task queue of TaskPool for execution.taskpool.execute(task, taskpool.Priority.HIGH).then((res: Object) => {// Processing after the so library is preloaded.Logger.info('PreloadSOByTaskPool：' + JSON.stringify(res));}).catch((error: BusinessError) => {Logger.error('PreloadSOByTaskPool: execute failed, ' + error.toString());});} catch (err) {Logger.error('PreloadSOByTaskPool: execute failed, ' + (err as BusinessError).toString());}
}

在Native层定义对外接口为getFileList、getRawFileContent、getRawFileDescriptor，映射C++接口分别为GetFileList、GetRawFileContent、GetRawFileDescriptor。通过获取Js的资源对象，并转为Native的资源对象，即可调用资源的Native接口，获取rawfile列表、rawfile文件内容以及rawfile描述符{fd, offset, length}。在Js侧导入"libentry.so"，通过getContext().resourceManager获取资源管理对象。调用src/main/cpp/types/libentry/index.d.ts中声明的接口，传入js的资源对象和相关参数获取对于rawfile相关资源信息。源码参考：[rawfile_demo.cpp] 。

/** Copyright (c) 2024 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.*/#include <js_native_api.h>
#include <js_native_api_types.h>
#include <vector>
#include "napi/native_api.h"
#include "rawfile/raw_file_manager.h"
#include "rawfile/raw_file.h"
#include "rawfile/raw_dir.h"
#include "hilog/log.h"const int GLOBAL_RESMGR = 0xFF00;
const char *TAG = "[Sample_rawfile]";
static napi_value GetFileList(napi_env env, napi_callback_info info) {OH_LOG_Print(LOG_APP, LOG_INFO, GLOBAL_RESMGR, TAG, "GetFileList Begin");size_t argc = 2;napi_value argv[2] = {nullptr};napi_get_cb_info(env, info, &argc, argv, nullptr, nullptr);napi_valuetype valueType;napi_typeof(env, argv[0], &valueType);NativeResourceManager *mNativeResMgr = OH_ResourceManager_InitNativeResourceManager(env, argv[0]);size_t strSize;char strBuf[256];napi_get_value_string_utf8(env, argv[1], strBuf, sizeof(strBuf), &strSize);std::string filename(strBuf, strSize);RawDir *rawDir = OH_ResourceManager_OpenRawDir(mNativeResMgr, filename.c_str());int count = OH_ResourceManager_GetRawFileCount(rawDir);std::vector<std::string> tempArray;for (int i = 0; i < count; i++) {std::string filename = OH_ResourceManager_GetRawFileName(rawDir, i);tempArray.emplace_back(filename);}napi_value fileList;napi_create_array(env, &fileList);for (size_t i = 0; i < tempArray.size(); i++) {napi_value jsString;napi_create_string_utf8(env, tempArray[i].c_str(), NAPI_AUTO_LENGTH, &jsString);napi_set_element(env, fileList, i, jsString);}OH_ResourceManager_CloseRawDir(rawDir);OH_ResourceManager_ReleaseNativeResourceManager(mNativeResMgr);return fileList;
}namespace {
napi_value CreateJsArrayValue(napi_env env, std::unique_ptr<uint8_t[]> &data, long length) {napi_value buffer;napi_status status = napi_create_external_arraybuffer(env, data.get(), length, [](napi_env env, void *data, void *hint) { delete[] static_cast<char *>(data); },nullptr, &buffer);if (status != napi_ok) {OH_LOG_Print(LOG_APP, LOG_ERROR, GLOBAL_RESMGR, TAG, "Failed to create external array buffer");return nullptr;}napi_value result = nullptr;status = napi_create_typedarray(env, napi_uint8_array, length, buffer, 0, &result);if (status != napi_ok) {OH_LOG_Print(LOG_APP, LOG_ERROR, GLOBAL_RESMGR, TAG, "Failed to create media typed array");return nullptr;}data.release();return result;
}
} // namespacestatic napi_value GetRawFileContent(napi_env env, napi_callback_info info) {OH_LOG_Print(LOG_APP, LOG_INFO, GLOBAL_RESMGR, TAG, "GetFileContent Begin");size_t argc = 2;napi_value argv[2] = {nullptr};napi_get_cb_info(env, info, &argc, argv, nullptr, nullptr);napi_valuetype valueType;napi_typeof(env, argv[0], &valueType);NativeResourceManager *mNativeResMgr = OH_ResourceManager_InitNativeResourceManager(env, argv[0]);size_t strSize;char strBuf[256];napi_get_value_string_utf8(env, argv[1], strBuf, sizeof(strBuf), &strSize);std::string filename(strBuf, strSize);RawFile *rawFile = OH_ResourceManager_OpenRawFile(mNativeResMgr, filename.c_str());if (rawFile != nullptr) {OH_LOG_Print(LOG_APP, LOG_INFO, GLOBAL_RESMGR, TAG, "OH_ResourceManager_OpenRawFile success");}long len = OH_ResourceManager_GetRawFileSize(rawFile);std::unique_ptr<uint8_t[]> data = std::make_unique<uint8_t[]>(len);int res = OH_ResourceManager_ReadRawFile(rawFile, data.get(), len);OH_ResourceManager_CloseRawFile(rawFile);OH_ResourceManager_ReleaseNativeResourceManager(mNativeResMgr);return CreateJsArrayValue(env, data, len);
}namespace {
napi_value createJsFileDescriptor(napi_env env, RawFileDescriptor &descriptor) {napi_value result;napi_status status = napi_create_object(env, &result);if (status != napi_ok) {return result;}napi_value fd;status = napi_create_int32(env, descriptor.fd, &fd);if (status != napi_ok) {return result;}status = napi_set_named_property(env, result, "fd", fd);if (status != napi_ok) {return result;}napi_value offset;status = napi_create_int64(env, descriptor.start, &offset);if (status != napi_ok) {return result;}status = napi_set_named_property(env, result, "offset", offset);if (status != napi_ok) {return result;}napi_value length;status = napi_create_int64(env, descriptor.length, &length);if (status != napi_ok) {return result;}status = napi_set_named_property(env, result, "length", length);if (status != napi_ok) {return result;}return result;
}
} // namespacestatic napi_value GetRawFileDescriptor(napi_env env, napi_callback_info info) {OH_LOG_Print(LOG_APP, LOG_INFO, GLOBAL_RESMGR, TAG, "GetRawFileDescriptor Begin");size_t argc = 2;napi_value argv[2] = {nullptr};napi_get_cb_info(env, info, &argc, argv, nullptr, nullptr);napi_valuetype valueType;napi_typeof(env, argv[0], &valueType);NativeResourceManager *mNativeResMgr = OH_ResourceManager_InitNativeResourceManager(env, argv[0]);size_t strSize;char strBuf[256];napi_get_value_string_utf8(env, argv[1], strBuf, sizeof(strBuf), &strSize);std::string filename(strBuf, strSize);RawFile *rawFile = OH_ResourceManager_OpenRawFile(mNativeResMgr, filename.c_str());if (rawFile != nullptr) {OH_LOG_Print(LOG_APP, LOG_INFO, GLOBAL_RESMGR, TAG, "OH_ResourceManager_OpenRawFile success");}RawFileDescriptor descriptor;OH_ResourceManager_GetRawFileDescriptor(rawFile, descriptor);OH_ResourceManager_CloseRawFile(rawFile);OH_ResourceManager_ReleaseNativeResourceManager(mNativeResMgr);return createJsFileDescriptor(env, descriptor);
}EXTERN_C_START
static napi_value Init(napi_env env, napi_value exports) {napi_property_descriptor desc[] = {{"getFileList", nullptr, GetFileList, nullptr, nullptr, nullptr, napi_default, nullptr},{"getRawFileContent", nullptr, GetRawFileContent, nullptr, nullptr, nullptr, napi_default, nullptr},{"getRawFileDescriptor", nullptr, GetRawFileDescriptor, nullptr, nullptr, nullptr, napi_default, nullptr}};napi_define_properties(env, exports, sizeof(desc) / sizeof(desc[0]), desc);return exports;
}
EXTERN_C_ENDstatic napi_module demoModule = {.nm_version = 1,.nm_flags = 0,.nm_filename = nullptr,.nm_register_func = Init,.nm_modname = "entry",.nm_priv = ((void *)0),.reserved = {0},
};extern "C" __attribute__((constructor)) void RegisterEntryModule(void) { napi_module_register(&demoModule); }

涉及到的相关接口：

接口名	描述
初始化native resource manager。	NativeResourceManager *OH_ResourceManager_InitNativeResourceManager(napi_env env, napi_value jsResMgr)
打开指定rawfile目录。	RawDir OH_ResourceManager_OpenRawDir(const NativeResourceManager mgr, const char *dirName)
获取指定rawfile目录下的rawfile文件数量。	int OH_ResourceManager_GetRawFileCount(RawDir *rawDir)
获取rawfile名字。	const char OH_ResourceManager_GetRawFileName(RawDir rawDir, int index)
打开指定rawfile文件。	RawFile OH_ResourceManager_OpenRawFile(const NativeResourceManager mgr, const char *fileName)
获取rawfile文件大小。	long OH_ResourceManager_GetRawFileSize(RawFile *rawFile)
读取rawfile文件内容。	int OH_ResourceManager_ReadRawFile(const RawFile rawFile, void buf, size_t length)
释放rawfile文件相关资源。	void OH_ResourceManager_CloseRawFile(RawFile *rawFile)
释放rawfile目录相关资源。	void OH_ResourceManager_CloseRawDir(RawDir *rawDir)
获取rawfile的fd。	bool OH_ResourceManager_GetRawFileDescriptor(const RawFile *rawFile, RawFileDescriptor &descriptor)
释放native resource manager相关资源。	void OH_ResourceManager_ReleaseNativeResourceManager(NativeResourceManager *resMgr)