OHos 如何获取resource manager 句柄

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背景

ohos4.0
RK3588

需求

需要在NDK层自行打开二进制文件, 逐帧读取数据进行处理. 查询到NDK层有如下API . API 依赖上层的ResourceManager句柄.

问题

如何在page 的index.ets 中获取JavaScipt resource manager句柄?

```

/**

@brief Obtains the native resource manager based on the JavaScipt resource manager.
You need to obtain the resource manager to process raw files as required.
@param env Indicates the pointer to the JavaScipt Native Interface (napi) environment.
@param jsResMgr Indicates the JavaScipt resource manager.
@return Returns the pointer to {@link NativeResourceManager}.
@since 8
@version 1.0 */

NativeResourceManager *OH_ResourceManager_InitNativeResourceManager(napi_env env, napi_value jsResMgr);

```

吴大夫

可以参考以下示例

创建native工程添加以下

#include <rawfile/raw_file.h>
#include <rawfile/raw_dir.h>
#include <rawfile/raw_file_manager.h>

// 示例一：获取rawfile文件列表 GetFileList
static napi_value GetFileList(napi_env env, napi_callback_info info)
{
    OH_LOG_Print(LOG_APP, LOG_ERROR, GLOBAL_RESMGR, tag, "NDKTest Begin");
    size_t requireArgc = 3;
    size_t argc = 2;
    napi_value argv[2] = { nullptr };
    // 获取参数信息
    napi_get_cb_info(env, info, &argc, argv, nullptr, nullptr);

    // argv[0]即为函数第一个参数Js资源对象，OH_ResourceManager_InitNativeResourceManager转为Native对象。
    NativeResourceManager *mNativeResMgr = OH_ResourceManager_InitNativeResourceManager(env, argv[0]);

    // 获取函数argv[1]，此为为rawfile相对路径
    size_t strSize;
    char strBuf[256];
    napi_get_value_string_utf8(env, argv[1], strBuf, sizeof(strBuf), &strSize);
    std::string dirName(strBuf, strSize);

    // 获取对应的rawDir指针对象
    RawDir* rawDir = OH_ResourceManager_OpenRawDir(mNativeResMgr, dirName.c_str());

    // 获取rawDir下文件及文件夹数量
    int count = OH_ResourceManager_GetRawFileCount(rawDir);

    // 遍历获取文件名称，并保存
    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);
    }

    // 关闭打开的指针对象
    OH_ResourceManager_CloseRawDir(rawDir);
    OH_ResourceManager_ReleaseNativeResourceManager(mNativeResMgr);
    return fileList;
}

// 示例二：获取rawfile文件内容 GetRawFileContent
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;
}
static napi_value GetRawFileContent(napi_env env, napi_callback_info info)
{
    OH_LOG_Print(LOG_APP, LOG_ERROR, GLOBAL_RESMGR, tag, "GetFileContent Begin");
    size_t requireArgc = 3;
    size_t argc = 2;
    napi_value argv[2] = { nullptr };
    // 获取参数信息
    napi_get_cb_info(env, info, &argc, argv, nullptr, nullptr);

    // argv[0]即为函数第一个参数Js资源对象，OH_ResourceManager_InitNativeResourceManager转为Native对象。
    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);

    // 获取rawfile指针对象
    RawFile *rawFile = OH_ResourceManager_OpenRawFile(mNativeResMgr, filename.c_str());
    if (rawFile != nullptr) {
        OH_LOG_Print(LOG_APP, LOG_ERROR, GLOBAL_RESMGR, tag, "OH_ResourceManager_OpenRawFile success");
    }
    // 获取rawfile大小并申请内存
    long len = OH_ResourceManager_GetRawFileSize(rawFile);
    std::unique_ptr<uint8_t[]> data= std::make_unique<uint8_t[]>(len);

    // 一次性读取rawfile全部内容
    int res = OH_ResourceManager_ReadRawFile(rawFile, data.get(), len);

    // 多次部分读取rawfile, 每次读取100 Byte。获取全部内容
    // long offset = 0;
    // while (OH_ResourceManager_GetRawFileRemainingLength(rawFile) > 0) {
    //     OH_ResourceManager_ReadRawFile(rawFile, data.get() + offset, 100);
    //     offset += 100;
    // }

    // 关闭打开的指针对象
    OH_ResourceManager_CloseRawFile(rawFile);
    OH_ResourceManager_ReleaseNativeResourceManager(mNativeResMgr);
    // 转为js对象
    return CreateJsArrayValue(env, data, len);
}

// 示例三：获取rawfile文件描述符 GetRawFileDescriptor
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;
}
static napi_value GetRawFileDescriptor(napi_env env, napi_callback_info info)
{
    OH_LOG_Print(LOG_APP, LOG_ERROR, GLOBAL_RESMGR, tag, "NDKTest GetRawFileDescriptor Begin");
    size_t requireArgc = 3;
    size_t argc = 2;
    napi_value argv[2] = { nullptr };
    // 获取参数信息
    napi_get_cb_info(env, info, &argc, argv, nullptr, nullptr);

    napi_valuetype valueType;
    napi_typeof(env, argv[0], &valueType);
    // 获取native的resourceManager对象
    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);
    // 获取rawfile指针对象
    RawFile *rawFile = OH_ResourceManager_OpenRawFile(mNativeResMgr, filename.c_str());
    if (rawFile != nullptr) {
        OH_LOG_Print(LOG_APP, LOG_ERROR, GLOBAL_RESMGR, tag, "OH_ResourceManager_OpenRawFile success");
    }
    // 获取rawfile的描述符RawFileDescriptor {fd, offset, length}
    RawFileDescriptor descriptor;
    OH_ResourceManager_GetRawFileDescriptor(rawFile, descriptor);
    // 关闭打开的指针对象
    OH_ResourceManager_CloseRawFile(rawFile);
    OH_ResourceManager_ReleaseNativeResourceManager(mNativeResMgr);
    // 转为js对象
    return createJsFileDescriptor(env,descriptor);
}
napi_value CreateJsBool(napi_env env, bool &bValue)
{
    napi_value jsValue = nullptr;
    if (napi_get_boolean(env, bValue, &jsValue) != napi_ok) {
        return nullptr;
    }
    return jsValue;
}
static napi_value IsRawDir(napi_env env, napi_callback_info info)
{
    OH_LOG_Print(LOG_APP, LOG_ERROR, GLOBAL_RESMGR, tag, "NDKTest IsRawDir Begin");
    size_t requireArgc = 3;
    size_t argc = 2;
    napi_value argv[2] = { nullptr };
    // 获取参数信息
    napi_get_cb_info(env, info, &argc, argv, nullptr, nullptr);

    napi_valuetype valueType;
    napi_typeof(env, argv[0], &valueType);
    // 获取native的resourceManager对象
    NativeResourceManager *mNativeResMgr = OH_ResourceManager_InitNativeResourceManager(env, argv[0]);

    napi_valuetype valueType1;
    napi_typeof(env, argv[1], &valueType);
    if (valueType1 == napi_undefined || valueType1 == napi_null) {
        bool temp = false;
        return CreateJsBool(env, temp);
    }
    size_t strSize;
    char strBuf[256];
    napi_get_value_string_utf8(env, argv[1], strBuf, sizeof(strBuf), &strSize);
    std::string filename(strBuf, strSize);
    // 获取rawfile指针对象
    bool result = OH_ResourceManager_OpenRawFile(mNativeResMgr, filename.c_str());
    OH_ResourceManager_ReleaseNativeResourceManager(mNativeResMgr);
    return CreateJsBool(env, result);
}

然后在应用中引用这个native库

import hilog from '@ohos.hilog';
import testNapi from 'libentry.so'  // 导入so
@Entry
@Component
struct Index {
    @State message: string = 'Hello World'
    private resmgr = getContext().resourceManager;  // 获取本应用包的资源对象
    build() {
        Row() {
        Column() {
            Text(this.message)
            .fontSize(50)
            .fontWeight(FontWeight.Bold)
            .onClick(() => {
                hilog.isLoggable(0x0000, 'testTag', hilog.LogLevel.INFO);
                let rawfilelist = testNapi.getFileList(this.resmgr, ""); //传入资源对象，以及访问的rawfile文件夹名称
                console.log("rawfilelist" + rawfilelist);
                let rawfileContet = testNapi.getRawFileContent(this.resmgr, "rawfile1.txt");
                console.log("rawfileContet" + rawfileContet);
                let rawfileDescriptor = testNapi.getRawFileDescriptor(this.resmgr, "rawfile1.txt");
                console.log("getRawFileDescriptor" + rawfileDescriptor.fd, rawfileDescriptor.offset, rawfileDescriptor.length);
                let ret = testNapi.isRawDir(this.resmgr, "rawfile1.txt");
            })
        }
        .width('100%')
        }
        .height('100%')
    }
}

OHos 如何获取resource manager 句柄

背景

需求

问题

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OHos 如何获取resource manager 句柄