mirror of
https://gitee.com/spark-store-project/spark-store
synced 2025-12-14 04:42:03 +08:00
103 lines
3.3 KiB
C++
103 lines
3.3 KiB
C++
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#pragma once
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#include "spkstore.h"
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/**
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* @note SpkDownloadMgr does NOT do download scheduling and other things; it's only a multithreaded
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* downloader; it manages the threads that are downloading stuff from the Internet.
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*/
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class SpkDownloadMgr : public QObject
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{
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Q_OBJECT
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public:
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SpkDownloadMgr(QObject *parent = nullptr);
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~SpkDownloadMgr();
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static constexpr int MaximumThreadRetryCount = 3;
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enum TaskResult
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{
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Success = 0,
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FailCannotCreateFile, ///< Failed because destination file cannot be created
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FailNoVaibleServer, ///< Failed because no server provides file size or download stalled on
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///< all of them
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Fail
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};
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/**
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* @brief DownloadWorker is not a real worker but more of a worker-like structure. It holds
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* information about one download thread, such as offset, total bytes and received bytes.
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* Workers' scheduling is still done by SpkDownloadMgr synchronously, avoiding
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* unnecessary race conditions and data safety problems.
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* DownloadWorker is also used in mFailureRetryQueue to indicate the blocks that needed
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* to be retried on other servers.
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*/
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struct DownloadWorker
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{
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QNetworkReply *Reply; ///< Reply from the network
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qint64 BeginOffset; ///< Where should a worker start downloading
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qint64 BytesNeeded; ///< How many bytes a worker should fetch in total
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qint64 BytesRecvd; ///< How many bytes a worker has received till now
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};
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struct RemoteFileInfo
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{
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qint64 Size = -1;
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bool SupportPartialDownload = false; ///< Whether this file can be downloaded multithreaded
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QByteArray Md5;
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};
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void SetNewServers(QList<QString> servers);
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/**
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* @note This function uses BLOCKING IO!
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*/
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static RemoteFileInfo GetRemoteFileInfo(QUrl url);
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private:
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QList<QString> mServers; ///< Multithreaded download
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QList<DownloadWorker> mScheduledWorkers;
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// If one scheduled task fails a few times in a row, we must give it up on that server and put
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// its responsible block onto this queue so we can try downloading the block from other servers
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QQueue<DownloadWorker> mFailureRetryQueue;
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QFile mDestFile;
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QString mDestFolder, mCurrentRemotePath;
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RemoteFileInfo mCurrentRemoteFileInfo;
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int mCurrentDownloadId;
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int mActiveWorkerCount;
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public slots:
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void SetDestinationFolder(QString path);
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/**
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* @brief StartNewDownload try to start new download task.
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* @param path File path. Domain name excluded. No leading slashes.
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* @param downloadId Emitted with progress, finish and error so the UI know whose status it is.
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* @return true for success and false for failure.
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*/
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bool StartNewDownload(QString path, int downloadId);
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bool PauseCurrentDownload();
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bool CancelCurrentDownload();
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private slots:
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void WorkerFinish();
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void WorkerDownloadProgress(); ///< Be connected to ***QNetworkReply::readyRead***
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private:
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void LinkReplyWithMe(QNetworkReply*);
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void TryScheduleFailureRetries();
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void TryScheduleFailureRetries(int i); ///< Try schedule on a specific task slot.
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signals:
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void DownloadProgressed(qint64 bytes, qint64 total);
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void DownloadStopped(TaskResult status, int id);
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};
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