Choker.h

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00001 /*
00002 
00003 Copyright (C) 2006-2007 by Peter Dimov.
00004 
00005 This file is part of Calitko (http://www.calitko.org).
00006 
00007 Calitko is free software; you can redistribute it and/or modify
00008 it under the terms of the GNU General Public License as published by
00009 the Free Software Foundation; either version 2 of the License, or
00010 (at your option) any later version.
00011 
00012 Calitko is distributed in the hope that it will be useful,
00013 but WITHOUT ANY WARRANTY; without even the implied warranty of
00014 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00015 GNU General Public License for more details.
00016 
00017 You should have received a copy of the GNU General Public License
00018 along with Calitko; if not, write to the Free Software
00019 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
00020 
00021 */
00022 
00023 #ifndef PROTOCOLS__BIT_TORRENT__TRANSFERS__CHOKER_H
00024 #define PROTOCOLS__BIT_TORRENT__TRANSFERS__CHOKER_H
00025 
00026 #include "Imports.h"
00027 #include "PacketProcessor.h"
00028 
00029 namespace Protocols {
00030 namespace BitTorrent {
00031 namespace Transfers {
00032 
00033 class Timer
00034 {
00035     CALITKO_MOCKABLE
00036 
00037 public:
00038     virtual         ~Timer() {}
00039     virtual void    start (const Callable <void ()> &, qint64 timeout) = 0;
00040     virtual void    stop() = 0;
00041 };
00042 
00043 class RandomNumberGenerator
00044 {
00045     CALITKO_MOCKABLE
00046 
00047 public:
00048     virtual         ~RandomNumberGenerator() {}
00049     virtual int     random() = 0;
00050 };
00051 
00053 class TransferManagerState
00054 {
00055     CALITKO_MOCKABLE
00056 
00057 public:
00058     virtual         ~TransferManagerState() {}
00059     virtual bool    isDownloading() const = 0;
00060 };
00061 
00063 
00078 class Choker : public PacketProcessor
00079 {
00080     CALITKO_TESTABLE
00081     REFERENCE_OBJECT (Choker)
00082 
00083 public:
00084                 Choker (Timer *,
00085                         RandomNumberGenerator *,
00086                         TransferManagerState *);
00087                 ~Choker();
00088 
00089     void        start();
00090     void        stop();
00091 
00092     void        chokingTime();
00093 
00094     // Interface PacketProcessor implementation:
00095     void        openedSession (TransferSession *);
00096     void        incomingPacket (TransferSession *, const Packet &);
00097     void        outgoingPacket (TransferSession *, const Packet &);
00098     void        closedSession (TransferSession *);
00099 
00100 private:
00101     typedef QList <TransferSession *> Sessions;
00102 
00103     void                    doOptimisticUnchokingIfTimeHasCome();
00104     Choker::Sessions        choseOptimisticlyUnchokedSessions();
00105     void                    sortSessionsForSelection();
00106     void                    reallocateUploadSlotsAndChokeUnchokeSessions();
00107     int                     numberOfUploadSlots() const;
00108     static void             chokeSessionIfNeeded (TransferSession *);
00109     static void             unchokeSessionIfNeeded (TransferSession *);
00110     static bool             moreDownloadedAndMoreInterested (
00111                                 const TransferSession *,
00112                                 const TransferSession *);
00113     static bool             moreUploadedAndMoreInterested (
00114                                 const TransferSession *,
00115                                 const TransferSession *);
00116 
00117     static const int        UploadSlotsCount = 4; // \todo Change at runtime?
00118     static const int        OptimisticChokingRate = 3;
00119     static const int        ChokingTimeout = 10000;
00120     static const Choke      choke;
00121     static const Unchoke    unchoke;
00122 
00123     Timer *                 timer;
00124     RandomNumberGenerator * randomNumberGenerator;
00125     TransferManagerState *  transferManagerState;
00126     Sessions                sessions;
00127     Sessions                newSessions;
00128     Sessions                optimisticlyUnchokedSessions;
00129     int                     optimisticChokingCounter;
00130 };
00131 
00132 } // namespace Transfers
00133 } // namespace BitTorrent
00134 } // namespace Protocols
00135 
00136 #endif // PROTOCOLS__BIT_TORRENT__TRANSFERS__CHOKER_H