qt5base-lts/examples/network/torrent/ratecontroller.cpp

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/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
** * Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** * Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in
** the documentation and/or other materials provided with the
** distribution.
** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
** the names of its contributors may be used to endorse or promote
** products derived from this software without specific prior written
** permission.
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
** $QT_END_LICENSE$
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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();
}