torrentclient.h Example File
network/torrent/torrentclient.h

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 #ifndef TORRENTCLIENT_H
 #define TORRENTCLIENT_H

 #include <QBitArray>
 #include <QHostAddress>
 #include <QList>

 class MetaInfo;
 class PeerWireClient;
 class TorrentClientPrivate;
 class TorrentPeer;
 class TorrentPiece;
 class QTimerEvent;

 class TorrentPeer {
 public:
     QHostAddress address;
     quint16 port;
     QString id;
     bool interesting;
     bool seed;
     uint lastVisited;
     uint connectStart;
     uint connectTime;
     QBitArray pieces;
     int numCompletedPieces;

     inline bool operator==(const TorrentPeer &other)
     {
         return port == other.port
             && address == other.address
             && id == other.id;
     }
 };

 class TorrentClient : public QObject
 {
     Q_OBJECT

 public:
     enum State {
         Idle,
         Paused,
         Stopping,
         Preparing,
         Searching,
         Connecting,
         WarmingUp,
         Downloading,
         Endgame,
         Seeding
     };
     enum Error {
         UnknownError,
         TorrentParseError,
         InvalidTrackerError,
         FileError,
         ServerError
     };

     TorrentClient(QObject *parent = 0);
     ~TorrentClient();

     bool setTorrent(const QString &fileName);
     bool setTorrent(const QByteArray &torrentData);
     MetaInfo metaInfo() const;

     void setMaxConnections(int connections);
     int maxConnections() const;

     void setDestinationFolder(const QString &directory);
     QString destinationFolder() const;

     void setDumpedState(const QByteArray &dumpedState);
     QByteArray dumpedState() const;

     // Progress and stats for download feedback.
     qint64 progress() const;
     void setDownloadedBytes(qint64 bytes);
     qint64 downloadedBytes() const;
     void setUploadedBytes(qint64 bytes);
     qint64 uploadedBytes() const;
     int connectedPeerCount() const;
     int seedCount() const;

     // Accessors for the tracker
     QByteArray peerId() const;
     QByteArray infoHash() const;
     quint16 serverPort() const;

     // State and error.
     State state() const;
     QString stateString() const;
     Error error() const;
     QString errorString() const;

 signals:
     void stateChanged(TorrentClient::State state);
     void error(TorrentClient::Error error);

     void downloadCompleted();
     void peerInfoUpdated();

     void dataSent(int uploadedBytes);
     void dataReceived(int downloadedBytes);
     void progressUpdated(int percentProgress);
     void downloadRateUpdated(int bytesPerSecond);
     void uploadRateUpdated(int bytesPerSecond);

     void stopped();

 public slots:
     void start();
     void stop();
     void setPaused(bool paused);
     void setupIncomingConnection(PeerWireClient *client);

 protected slots:
     void timerEvent(QTimerEvent *event);

 private slots:
     // File management
     void sendToPeer(int readId, int pieceIndex, int begin, const QByteArray &data);
     void fullVerificationDone();
     void pieceVerified(int pieceIndex, bool ok);
     void handleFileError();

     // Connection handling
     void connectToPeers();
     QList<TorrentPeer *> weighedFreePeers() const;
     void setupOutgoingConnection();
     void initializeConnection(PeerWireClient *client);
     void removeClient();
     void peerPiecesAvailable(const QBitArray &pieces);
     void peerRequestsBlock(int pieceIndex, int begin, int length);
     void blockReceived(int pieceIndex, int begin, const QByteArray &data);
     void peerWireBytesWritten(qint64 bytes);
     void peerWireBytesReceived(qint64 bytes);
     int blocksLeftForPiece(const TorrentPiece *piece) const;

     // Scheduling
     void scheduleUploads();
     void scheduleDownloads();
     void schedulePieceForClient(PeerWireClient *client);
     void requestMore(PeerWireClient *client);
     int requestBlocks(PeerWireClient *client, TorrentPiece *piece, int maxBlocks);
     void peerChoked();
     void peerUnchoked();

     // Tracker handling
     void addToPeerList(const QList<TorrentPeer> &peerList);
     void trackerStopped();

     // Progress
     void updateProgress(int progress = -1);

 private:
     TorrentClientPrivate *d;
     friend class TorrentClientPrivate;
 };

 #endif