distributeddatamgr_appdatamgr/frameworks/jskitsimpl/common/include/napi_async_proxy.h

/*
 * Copyright (c) 2021 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.
 */
#ifndef PREFERENCES_JSKIT_NAPI_ASYNC_PROXY_H
#define PREFERENCES_JSKIT_NAPI_ASYNC_PROXY_H
#include <vector>

#include "napi/native_api.h"
#include "napi/native_common.h"
#include "napi/native_node_api.h"
#include "securec.h"

namespace OHOS {
namespace AppDataMgrJsKit {
constexpr int MAX_INPUT_COUNT = 10;
constexpr int OK = 0;
constexpr int ERR = -1;

// T inherits AysncContext
template<class T> class NapiAsyncProxy {
public:
    constexpr static int RESULT_COUNT = 2;
    using InputParser = void (*)(const napi_env &, const napi_value &, T *);
    using NapiAsyncExecute = int (*)(T *);
    using NapiAsyncComplete = int (*)(T *, napi_value &);

    // AsyncContext base
    struct AysncContext {
        AysncContext()
        {
        }
        virtual ~AysncContext()
        {
            if (env == nullptr) {
                return;
            }
            napi_delete_async_work(env, work);
            napi_delete_reference(env, callbackRef);
        }
        napi_env env = nullptr;
        napi_callback_info info = nullptr;
        napi_async_work work = nullptr;
        napi_deferred deferred = nullptr;
        napi_ref callbackRef = nullptr;
        NapiAsyncExecute execFunc = nullptr;
        int execStatus = ERR;
        NapiAsyncComplete completeFunc = nullptr;
        void *boundObj = nullptr;
    };

public:
    void Init(napi_env env, napi_callback_info info)
    {
        asyncContext = new T();
        if (asyncContext == nullptr) {
            return;
        }
        asyncContext->env = env;
        asyncContext->info = info;
    }

    static void DefParserThis(const napi_env &env, const napi_value &self, T *context)
    {
        napi_unwrap(env, self, &context->boundObj);
    }

    void ParseInputs(const std::vector<InputParser> &parsers, InputParser parserThis = DefParserThis)
    {
        if (asyncContext == nullptr) {
            return;
        }

        napi_value thisObj = nullptr;
        size_t argc = parsers.size() + 1;
        napi_value args[MAX_INPUT_COUNT] = { 0 };
        napi_get_cb_info(asyncContext->env, asyncContext->info, &argc, args, &thisObj, nullptr);
        for (size_t i = 0; i < argc && argc <= MAX_INPUT_COUNT; i++) {
            if (i >= parsers.size()) {
                napi_valuetype valueType = napi_undefined;
                napi_typeof(asyncContext->env, args[i], &valueType);
                if (valueType == napi_function) {
                    napi_create_reference(asyncContext->env, args[i], 1, &asyncContext->callbackRef);
                }
                break;
            }
            auto *parserFunction = parsers[i];
            if (parserFunction != nullptr) {
                parserFunction(asyncContext->env, args[i], this->asyncContext);
            }
        }
        parserThis(asyncContext->env, thisObj, asyncContext);
    }

    napi_value DoAsyncWork(std::string resourceName, NapiAsyncExecute execFunc, NapiAsyncComplete completeFunc)
    {
        if (asyncContext == nullptr) {
            return nullptr;
        }

        napi_value ret = nullptr;
        if (asyncContext->callbackRef == nullptr) {
            napi_create_promise(asyncContext->env, &asyncContext->deferred, &ret);
        } else {
            napi_get_undefined(asyncContext->env, &ret);
        }

        napi_value resource = nullptr;
        napi_create_string_utf8(asyncContext->env, resourceName.c_str(), NAPI_AUTO_LENGTH, &resource);

        asyncContext->execFunc = execFunc;
        asyncContext->completeFunc = completeFunc;
        napi_create_async_work(
            asyncContext->env, nullptr, resource,
            [](napi_env env, void *data) {
                T *context = (T *)data;
                context->execStatus = context->execFunc(context);
            },
            [](napi_env env, napi_status status, void *data) {
                T *context = (T *)data;
                napi_value output = nullptr;
                int completeStatus = context->completeFunc(context, output);
                napi_value result[RESULT_COUNT] = { 0 };
                if (context->execStatus == OK && completeStatus == OK) {
                    napi_get_undefined(env, &result[0]);
                    result[1] = output;
                } else {
                    napi_value message = nullptr;
                    napi_create_string_utf8(env, "async call failed", NAPI_AUTO_LENGTH, &message);
                    napi_create_error(env, nullptr, message, &result[0]);
                    napi_get_undefined(env, &result[1]);
                }
                if (context->deferred) {
                    // promise
                    if (context->execStatus == OK && completeStatus == OK) {
                        napi_resolve_deferred(env, context->deferred, result[1]);
                    } else {
                        napi_reject_deferred(env, context->deferred, result[0]);
                    }
                } else {
                    // callback
                    napi_value callback = nullptr;
                    napi_get_reference_value(env, context->callbackRef, &callback);
                    napi_value callbackResult = nullptr;
                    napi_call_function(env, nullptr, callback, RESULT_COUNT, result, &callbackResult);
                }
                delete context;
            },
            (void *)asyncContext, &asyncContext->work);

        napi_queue_async_work(asyncContext->env, asyncContext->work);
        return ret;
    }

private:
    T *asyncContext;
};
} // namespace AppDataMgrJsKit
} // namespace OHOS
#endif