examples/network/torrent/ratecontroller.cpp

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  41
  42 #include "peerwireclient.h"
  43 #include "ratecontroller.h"
  44
  45 #include <QtCore>
  46
  47 Q_GLOBAL_STATIC(RateController, rateController)
  48
  49 RateController *RateController::instance()
  50 {
  51     return rateController();
  52 }
  53
  54 void RateController::addSocket(PeerWireClient *socket)
  55 {
  56     connect(socket, SIGNAL(readyToTransfer()), this, SLOT(scheduleTransfer()));
  57     socket->setReadBufferSize(downLimit * 4);
  58     sockets << socket;
  59     scheduleTransfer();
  60 }
  61
  62 void RateController::removeSocket(PeerWireClient *socket)
  63 {
  64     disconnect(socket, SIGNAL(readyToTransfer()), this, SLOT(scheduleTransfer()));
  65     socket->setReadBufferSize(0);
  66     sockets.remove(socket);
  67 }
  68
  69 void RateController::setDownloadLimit(int bytesPerSecond)
  70 {
  71     downLimit = bytesPerSecond;
  72     foreach (PeerWireClient *socket, sockets)
  73         socket->setReadBufferSize(downLimit * 4);
  74 }
  75
  76 void RateController::scheduleTransfer()
  77 {
  78     if (transferScheduled)
  79         return;
  80     transferScheduled = true;
  81     QTimer::singleShot(50, this, SLOT(transfer()));
  82 }
  83
  84 void RateController::transfer()
  85 {
  86     transferScheduled = false;
  87     if (sockets.isEmpty())
  88         return;
  89
  90     int msecs = 1000;
  91     if (!stopWatch.isNull())
  92         msecs = qMin(msecs, stopWatch.elapsed());
  93
  94     qint64 bytesToWrite = (upLimit * msecs) / 1000;
  95     qint64 bytesToRead = (downLimit * msecs) / 1000;
  96     if (bytesToWrite == 0 && bytesToRead == 0) {
  97         scheduleTransfer();
  98         return;
  99     }
 100
 101     QSet<PeerWireClient *> pendingSockets;
 102     foreach (PeerWireClient *client, sockets) {
 103         if (client->canTransferMore())
 104             pendingSockets << client;
 105     }
 106     if (pendingSockets.isEmpty())
 107         return;
 108
 109     stopWatch.start();
 110
 111     bool canTransferMore;
 112     do {
 113         canTransferMore = false;
 114         qint64 writeChunk = qMax<qint64>(1, bytesToWrite / pendingSockets.size());
 115         qint64 readChunk = qMax<qint64>(1, bytesToRead / pendingSockets.size());
 116
 117         QSetIterator<PeerWireClient *> it(pendingSockets);
 118         while (it.hasNext() && (bytesToWrite > 0 || bytesToRead > 0)) {
 119             PeerWireClient *socket = it.next();
 120             if (socket->state() != QAbstractSocket::ConnectedState) {
 121                 pendingSockets.remove(socket);
 122                 continue;
 123             }
 124
 125             bool dataTransferred = false;
 126             qint64 available = qMin<qint64>(socket->socketBytesAvailable(), readChunk);
 127             if (available > 0) {
 128                 qint64 readBytes = socket->readFromSocket(qMin<qint64>(available, bytesToRead));
 129                 if (readBytes > 0) {
 130                     bytesToRead -= readBytes;
 131                     dataTransferred = true;
 132                 }
 133             }
 134
 135             if (upLimit * 2 > socket->bytesToWrite()) {
 136                 qint64 chunkSize = qMin<qint64>(writeChunk, bytesToWrite);
 137                 qint64 toWrite = qMin(upLimit * 2 - socket->bytesToWrite(), chunkSize);
 138                 if (toWrite > 0) {
 139                     qint64 writtenBytes = socket->writeToSocket(toWrite);
 140                     if (writtenBytes > 0) {
 141                         bytesToWrite -= writtenBytes;
 142                         dataTransferred = true;
 143                     }
 144                 }
 145             }
 146
 147             if (dataTransferred && socket->canTransferMore())
 148                 canTransferMore = true;
 149             else
 150                 pendingSockets.remove(socket);
 151         }
 152     } while (canTransferMore && (bytesToWrite > 0 || bytesToRead > 0) && !pendingSockets.isEmpty());
 153
 154     if (canTransferMore || bytesToWrite == 0 || bytesToRead == 0)
 155         scheduleTransfer();
 156 }