axmol/core/network/Downloader-wasm.cpp

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#include "platform/FileUtils.h"
#include "network/Downloader-wasm.h"
#include <emscripten.h>

using namespace std;

namespace ax { namespace network {

        static int sDownloaderCounter;

        struct DownloadTaskEmscripten : public IDownloadTask
        {
            explicit DownloadTaskEmscripten(unsigned int id_)
            :id(id_)
            ,bytesReceived(0)
            ,fetch(NULL)
            {
                AXLOGD("Construct DownloadTaskEmscripten: {}", fmt::ptr(this));
            }
            virtual  ~DownloadTaskEmscripten()
            {
                AXLOGD("Destruct DownloadTaskEmscripten: {}", fmt::ptr(this));
            }

            int bytesReceived;
            unsigned int id;
            emscripten_fetch_t * fetch;
            shared_ptr<const DownloadTask> task;    // reference to DownloadTask, when task finish, release
        };

        DownloaderEmscripten::DownloaderEmscripten(const DownloaderHints& hints)
        : _id(++sDownloaderCounter)
        , hints(hints)
        {
            AXLOGD("Construct DownloaderEmscripten: {}", fmt::ptr(this));
        }

        DownloaderEmscripten::~DownloaderEmscripten()
        {
            AXLOGD("Destruct DownloaderEmscripten: {}", fmt::ptr(this));
            for (auto iter = _taskMap.begin(); iter != _taskMap.end(); ++iter)
            {
                if(iter->second->fetch != NULL) {
                    emscripten_fetch_close(iter->second->fetch);
                }
            }
        }

        void DownloaderEmscripten::startTask(std::shared_ptr<DownloadTask>& task)
        {
            emscripten_fetch_attr_t attr;
            emscripten_fetch_attr_init(&attr);
            strcpy(attr.requestMethod, "GET");
            attr.attributes = EMSCRIPTEN_FETCH_LOAD_TO_MEMORY | EMSCRIPTEN_FETCH_PERSIST_FILE;
            if(task->storagePath.length() == 0) {
                attr.onsuccess = DownloaderEmscripten::onDataLoad;
            }else{
                attr.onsuccess = DownloaderEmscripten::onLoad;
            }
            attr.onprogress = DownloaderEmscripten::onProgress;
            attr.onerror = DownloaderEmscripten::onError;
            attr.timeoutMSecs = this->hints.timeoutInSeconds * 1000;
            emscripten_fetch_t *fetch = emscripten_fetch(&attr, task->requestURL.c_str());
            fetch->userData = this;

            DownloadTaskEmscripten *coTask = new DownloadTaskEmscripten(fetch->id);
            coTask->task = task;
            
            AXLOGD("DownloaderEmscripten::createCoTask id: {}", coTask->id);
            _taskMap.insert(make_pair(coTask->id, coTask));
        }

        void DownloaderEmscripten::onDataLoad(emscripten_fetch_t *fetch)
        {
            unsigned int taskId = fetch->id;
            uint64_t size = fetch->numBytes;
            AXLOGD("DownloaderEmscripten::onDataLoad(taskId: {}, size: {})", taskId, size);
            DownloaderEmscripten* downloader = reinterpret_cast<DownloaderEmscripten*>(fetch->userData);
            auto iter = downloader->_taskMap.find(taskId);
            if (downloader->_taskMap.end() == iter)
            {
                AXLOGD("DownloaderEmscripten::onDataLoad can't find task with id: {}, size: {}", taskId, size);
                return;
            }
            DownloadTaskEmscripten *coTask = iter->second;
            std::vector<unsigned char> buf(reinterpret_cast<const uint8_t*>(fetch->data), reinterpret_cast<const uint8_t*>(fetch->data) + size);
            emscripten_fetch_close(fetch);
            coTask->fetch = fetch = NULL;
            
            downloader->_taskMap.erase(iter);
            downloader->onTaskFinish(*coTask->task,
                DownloadTask::ERROR_NO_ERROR,
                0,
                "",
                buf
            );
            
            coTask->task.reset();
        }

        void DownloaderEmscripten::onLoad(emscripten_fetch_t *fetch)
        {
            unsigned int taskId = fetch->id;
            uint64_t size = fetch->numBytes;
            AXLOGD("DownloaderEmscripten::onLoad(taskId: {}, size: {})", taskId, size);
            DownloaderEmscripten* downloader = reinterpret_cast<DownloaderEmscripten*>(fetch->userData);
            auto iter = downloader->_taskMap.find(taskId);
            if (downloader->_taskMap.end() == iter)
            {
                AXLOGD("DownloaderEmscripten::onLoad can't find task with id: {}, size: {}", taskId, size);
                return;
            }
            DownloadTaskEmscripten *coTask = iter->second;
            vector<unsigned char> buf;
            downloader->_taskMap.erase(iter);
            
            string storagePath = coTask->task->storagePath;
            int errCode = DownloadTask::ERROR_NO_ERROR;
            int errCodeInternal = 0;
            string errDescription;
            do
            {
                auto util = FileUtils::getInstance();
                if (util->isFileExist(storagePath))
                {
                    if (false == util->removeFile(storagePath))
                    {
                        errCode = DownloadTask::ERROR_REMOVE_FILE_FAILED;
                        errCodeInternal = 0;
                        errDescription = "Can't remove old file: ";
                        errDescription.append(storagePath);
                        break;
                    }
                }

                string dir;
                size_t found = storagePath.find_last_of("/\\");
                if (found == string::npos)
                {
                    errCode = DownloadTask::ERROR_INVALID_PARAMS;
                    errCodeInternal = 0;
                    errDescription = "Can't find dirname in storagePath.";
                    break;
                }

                // ensure directory is exist
                dir = storagePath.substr(0, found + 1);
                if (false == util->isDirectoryExist(dir))
                {
                    if (false == util->createDirectory(dir))
                    {
                        errCode = DownloadTask::ERROR_CREATE_DIR_FAILED;
                        errCodeInternal = 0;
                        errDescription = "Can't create dir:";
                        errDescription.append(dir);
                        break;
                    }
                }

                // open file
                auto _fs = util->openFileStream(storagePath, IFileStream::Mode::READ);
                if (!_fs)
                {
                    errCode = DownloadTask::ERROR_OPEN_FILE_FAILED;
                    errCodeInternal = 0;
                    errDescription = "Can't open file:";
                    errDescription.append(storagePath);
                    break;
                }

                _fs->write(fetch->data, static_cast<unsigned int>(size));

            } while (0);
            emscripten_fetch_close(fetch);
            coTask->fetch = fetch = NULL;

            downloader->onTaskFinish(*coTask->task,
                errCode,
                errCodeInternal,
                errDescription,
                buf
            );
            coTask->task.reset();
        }

        void DownloaderEmscripten::onProgress(emscripten_fetch_t *fetch)
        {
            uint64_t dlTotal = fetch->totalBytes;
            uint64_t dlNow = fetch->dataOffset;
            unsigned int taskId = fetch->id;
            AXLOGD("DownloaderEmscripten::onProgress(taskId: {}, dlnow: {}, dltotal: {})", taskId, dlNow, dlTotal);
            DownloaderEmscripten* downloader = reinterpret_cast<DownloaderEmscripten*>(fetch->userData);
            auto iter = downloader->_taskMap.find(taskId);
            if (downloader->_taskMap.end() == iter)
            {
                AXLOGD("DownloaderEmscripten::onProgress can't find task with id: {}", taskId);
                return;
            }

            if (dlTotal == 0) {
                AXLOGD("DownloaderEmscripten::onProgress dlTotal unknown, usually caused by unknown content-length header {}", taskId);
                return;
            }

            DownloadTaskEmscripten *coTask = iter->second;
            function<int64_t(void*, int64_t)> transferDataToBuffer; // just a placeholder
            // int dl = dlNow - coTask->bytesReceived;
            coTask->bytesReceived = dlNow;
            downloader->onTaskProgress(*coTask->task, transferDataToBuffer);
        }

        void DownloaderEmscripten::onError(emscripten_fetch_t *fetch)
        {
            unsigned int taskId = fetch->id;
            AXLOGD("DownloaderEmscripten::onLoad(taskId: {})", taskId);
            DownloaderEmscripten* downloader = reinterpret_cast<DownloaderEmscripten*>(fetch->userData);
            auto iter = downloader->_taskMap.find(taskId);
            if (downloader->_taskMap.end() == iter)
            {
                emscripten_fetch_close(fetch);
                AXLOGD("DownloaderEmscripten::onLoad can't find task with id: {}", taskId);
                return;
            }
            DownloadTaskEmscripten *coTask = iter->second;
            vector<unsigned char> buf;
            downloader->_taskMap.erase(iter);
            downloader->onTaskFinish(*coTask->task,
                DownloadTask::ERROR_IMPL_INTERNAL,
                fetch->status,
                fetch->statusText,
                buf
            );

            emscripten_fetch_close(fetch);
            coTask->fetch = fetch = NULL;
            coTask->task.reset();
        }
    }
}  // namespace cocos2d::network