ratecontroller.cpp Example File | Qt Network 5.6

Qt 5.6 | Qt Network | Torrent Example | ratecontroller.cpp Example File

Qt 5.6.2 Reference Documentation

# ratecontroller.cpp Example File

torrent/ratecontroller.cpp

      /****************************************************************************
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      ** Contact: http://www.qt.io/licensing/
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      ** This file is part of the examples of the Qt Toolkit.
      **
      ** $QT_BEGIN_LICENSE:BSD$
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      #include "peerwireclient.h"
      #include "ratecontroller.h"

      #include <QtCore>

      Q_GLOBAL_STATIC(RateController, rateController)

      RateController *RateController::instance()
      {
          return rateController();
      }

      void RateController::addSocket(PeerWireClient *socket)
      {
          connect(socket, SIGNAL(readyToTransfer()), this, SLOT(scheduleTransfer()));
          socket->setReadBufferSize(downLimit * 4);
          sockets << socket;
          scheduleTransfer();
      }

      void RateController::removeSocket(PeerWireClient *socket)
      {
          disconnect(socket, SIGNAL(readyToTransfer()), this, SLOT(scheduleTransfer()));
          socket->setReadBufferSize(0);
          sockets.remove(socket);
      }

      void RateController::setDownloadLimit(int bytesPerSecond)
      {
          downLimit = bytesPerSecond;
          foreach (PeerWireClient *socket, sockets)
              socket->setReadBufferSize(downLimit * 4);
      }

      void RateController::scheduleTransfer()
      {
          if (transferScheduled)
              return;
          transferScheduled = true;
          QTimer::singleShot(50, this, SLOT(transfer()));
      }

      void RateController::transfer()
      {
          transferScheduled = false;
          if (sockets.isEmpty())
              return;

          int msecs = 1000;
          if (!stopWatch.isNull())
              msecs = qMin(msecs, stopWatch.elapsed());

          qint64 bytesToWrite = (upLimit * msecs) / 1000;
          qint64 bytesToRead = (downLimit * msecs) / 1000;
          if (bytesToWrite == 0 && bytesToRead == 0) {
              scheduleTransfer();
              return;
          }

          QSet<PeerWireClient *> pendingSockets;
          foreach (PeerWireClient *client, sockets) {
              if (client->canTransferMore())
                  pendingSockets << client;
          }
          if (pendingSockets.isEmpty())
              return;

          stopWatch.start();

          bool canTransferMore;
          do {
              canTransferMore = false;
              qint64 writeChunk = qMax<qint64>(1, bytesToWrite / pendingSockets.size());
              qint64 readChunk = qMax<qint64>(1, bytesToRead / pendingSockets.size());

              QSetIterator<PeerWireClient *> it(pendingSockets);
              while (it.hasNext() && (bytesToWrite > 0 || bytesToRead > 0)) {
                  PeerWireClient *socket = it.next();
                  if (socket->state() != QAbstractSocket::ConnectedState) {
                      pendingSockets.remove(socket);
                      continue;
                  }

                  bool dataTransferred = false;
                  qint64 available = qMin<qint64>(socket->socketBytesAvailable(), readChunk);
                  if (available > 0) {
                      qint64 readBytes = socket->readFromSocket(qMin<qint64>(available, bytesToRead));
                      if (readBytes > 0) {
                          bytesToRead -= readBytes;
                          dataTransferred = true;
                      }
                  }

                  if (upLimit * 2 > socket->bytesToWrite()) {
                      qint64 chunkSize = qMin<qint64>(writeChunk, bytesToWrite);
                      qint64 toWrite = qMin(upLimit * 2 - socket->bytesToWrite(), chunkSize);
                      if (toWrite > 0) {
                          qint64 writtenBytes = socket->writeToSocket(toWrite);
                          if (writtenBytes > 0) {
                              bytesToWrite -= writtenBytes;
                              dataTransferred = true;
                          }
                      }
                  }

                  if (dataTransferred && socket->canTransferMore())
                      canTransferMore = true;
                  else
                      pendingSockets.remove(socket);
              }
          } while (canTransferMore && (bytesToWrite > 0 || bytesToRead > 0) && !pendingSockets.isEmpty());

          if (canTransferMore || bytesToWrite == 0 || bytesToRead == 0)
              scheduleTransfer();
      }