Cleanup network examples

Cleanup network examples:
 - use nullptr
 - use member-init
 - adjust includes
 - use new-style connects

Change-Id: I80aa230168e5aec88a1bc93bbf49a471bfc30e7b
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>

14 files changed, 148 insertions, 146 deletions

diff --git a/examples/network/torrent/addtorrentdialog.cpp b/examples/network/torrent/addtorrentdialog.cpp
index c87110ac4a..129ad8c968 100644
--- a/examples/network/torrent/addtorrentdialog.cpp
+++ b/examples/network/torrent/addtorrentdialog.cpp
@@ -73,12 +73,12 @@ AddTorrentDialog::AddTorrentDialog(QWidget *parent)
 {
     ui.setupUi(this);
 
-    connect(ui.browseTorrents, SIGNAL(clicked()),
-            this, SLOT(selectTorrent()));
-    connect(ui.browseDestination, SIGNAL(clicked()),
-            this, SLOT(selectDestination()));
-    connect(ui.torrentFile, SIGNAL(textChanged(QString)),
-            this, SLOT(setTorrent(QString)));
+    connect(ui.browseTorrents, &QPushButton::clicked,
+            this, &AddTorrentDialog::selectTorrent);
+    connect(ui.browseDestination, &QPushButton::clicked,
+            this, &AddTorrentDialog::selectDestination);
+    connect(ui.torrentFile, &QLineEdit::textChanged,
+            this, &AddTorrentDialog::setTorrent);
 
     ui.destinationFolder->setText(destinationDirectory = QDir::current().path());
     ui.torrentFile->setFocus();
diff --git a/examples/network/torrent/addtorrentdialog.h b/examples/network/torrent/addtorrentdialog.h
index b5bd1df84f..00546c624c 100644
--- a/examples/network/torrent/addtorrentdialog.h
+++ b/examples/network/torrent/addtorrentdialog.h
@@ -60,7 +60,7 @@ class AddTorrentDialog : public QDialog
     Q_OBJECT
 
 public:
-    AddTorrentDialog(QWidget *parent = 0);
+    AddTorrentDialog(QWidget *parent = nullptr);
 
     QString torrentFileName() const;
     QString destinationFolder() const;
diff --git a/examples/network/torrent/filemanager.h b/examples/network/torrent/filemanager.h
index 82f9983ea6..1438ed5404 100644
--- a/examples/network/torrent/filemanager.h
+++ b/examples/network/torrent/filemanager.h
@@ -70,7 +70,7 @@ class FileManager : public QThread
     Q_OBJECT
 
 public:
-    FileManager(QObject *parent = 0);
+    FileManager(QObject *parent = nullptr);
     virtual ~FileManager();
 
     inline void setMetaInfo(const MetaInfo &info) { metaInfo = info; }
diff --git a/examples/network/torrent/mainwindow.cpp b/examples/network/torrent/mainwindow.cpp
index 704012ef6d..331fa12944 100644
--- a/examples/network/torrent/mainwindow.cpp
+++ b/examples/network/torrent/mainwindow.cpp
@@ -60,7 +60,7 @@ class TorrentView : public QTreeWidget
 {
     Q_OBJECT
 public:
-    TorrentView(QWidget *parent = 0);
+    TorrentView(QWidget *parent = nullptr);
 
 #if QT_CONFIG(draganddrop)
 signals:
@@ -110,7 +110,7 @@ public:
 };
 
 MainWindow::MainWindow(QWidget *parent)
-    : QMainWindow(parent), quitDialog(0), saveChanges(false)
+    : QMainWindow(parent), quitDialog(nullptr), saveChanges(false)
 {
     // Initialize some static strings
     QStringList headers;
@@ -147,12 +147,12 @@ MainWindow::MainWindow(QWidget *parent)
     fileMenu->addAction(pauseTorrentAction);
     fileMenu->addAction(removeTorrentAction);
     fileMenu->addSeparator();
-    fileMenu->addAction(QIcon(":/icons/exit.png"), tr("E&xit"), this, SLOT(close()));
+    fileMenu->addAction(QIcon(":/icons/exit.png"), tr("E&xit"), this, &MainWindow::close);
 
     // Help menu
     QMenu *helpMenu = menuBar()->addMenu(tr("&Help"));
-    helpMenu->addAction(tr("&About"), this, SLOT(about()));
-    helpMenu->addAction(tr("About &Qt"), qApp, SLOT(aboutQt()));
+    helpMenu->addAction(tr("&About"), this, &MainWindow::about);
+    helpMenu->addAction(tr("About &Qt"), qApp, QApplication::aboutQt);
 
     // Top toolbar
     QToolBar *topBar = new QToolBar(tr("Tools"));
@@ -188,24 +188,24 @@ MainWindow::MainWindow(QWidget *parent)
 #endif
 
     // Set up connections
-    connect(torrentView, SIGNAL(itemSelectionChanged()),
-            this, SLOT(setActionsEnabled()));
-    connect(torrentView, SIGNAL(fileDropped(QString)),
-            this, SLOT(acceptFileDrop(QString)));
-    connect(uploadLimitSlider, SIGNAL(valueChanged(int)),
-            this, SLOT(setUploadLimit(int)));
-    connect(downloadLimitSlider, SIGNAL(valueChanged(int)),
-            this, SLOT(setDownloadLimit(int)));
-    connect(newTorrentAction, SIGNAL(triggered()),
-            this, SLOT(addTorrent()));
-    connect(pauseTorrentAction, SIGNAL(triggered()),
-            this, SLOT(pauseTorrent()));
-    connect(removeTorrentAction, SIGNAL(triggered()),
-            this, SLOT(removeTorrent()));
-    connect(upActionTool, SIGNAL(triggered(bool)),
-            this, SLOT(moveTorrentUp()));
-    connect(downActionTool, SIGNAL(triggered(bool)),
-            this, SLOT(moveTorrentDown()));
+    connect(torrentView, &TorrentView::itemSelectionChanged,
+            this, &MainWindow::setActionsEnabled);
+    connect(torrentView, &TorrentView::fileDropped,
+            this, &MainWindow::acceptFileDrop);
+    connect(uploadLimitSlider, &QSlider::valueChanged,
+            this, &MainWindow::setUploadLimit);
+    connect(downloadLimitSlider, &QSlider::valueChanged,
+            this, &MainWindow::setDownloadLimit);
+    connect(newTorrentAction, &QAction::triggered,
+            this, QOverload<>::of(&MainWindow::addTorrent));
+    connect(pauseTorrentAction, &QAction::triggered,
+            this, &MainWindow::pauseTorrent);
+    connect(removeTorrentAction, &QAction::triggered,
+            this, &MainWindow::removeTorrent);
+    connect(upActionTool, &QAction::triggered,
+            this, &MainWindow::moveTorrentUp);
+    connect(downActionTool, &QAction::triggered,
+            this, &MainWindow::moveTorrentDown);
 
     // Load settings and start
     setWindowTitle(tr("Torrent Client"));
@@ -297,7 +297,7 @@ bool MainWindow::addTorrent()
     addTorrent(fileName, addTorrentDialog->destinationFolder());
     if (!saveChanges) {
         saveChanges = true;
-        QTimer::singleShot(1000, this, SLOT(saveSettings()));
+        QTimer::singleShot(1000, this, &MainWindow::saveSettings);
     }
     return true;
 }
@@ -311,7 +311,8 @@ void MainWindow::removeTorrent()
 
     // Stop the client.
     client->disconnect();
-    connect(client, SIGNAL(stopped()), this, SLOT(torrentStopped()));
+    connect(client, &TorrentClient::stopped,
+            this, &MainWindow::torrentStopped);
     client->stop();
 
     // Remove the row from the view.
@@ -379,13 +380,20 @@ bool MainWindow::addTorrent(const QString &fileName, const QString &destinationF
     client->setDumpedState(resumeState);
 
     // Setup the client connections.
-    connect(client, SIGNAL(stateChanged(TorrentClient::State)), this, SLOT(updateState(TorrentClient::State)));
-    connect(client, SIGNAL(peerInfoUpdated()), this, SLOT(updatePeerInfo()));
-    connect(client, SIGNAL(progressUpdated(int)), this, SLOT(updateProgress(int)));
-    connect(client, SIGNAL(downloadRateUpdated(int)), this, SLOT(updateDownloadRate(int)));
-    connect(client, SIGNAL(uploadRateUpdated(int)), this, SLOT(updateUploadRate(int)));
-    connect(client, SIGNAL(stopped()), this, SLOT(torrentStopped()));
-    connect(client, SIGNAL(error(TorrentClient::Error)), this, SLOT(torrentError(TorrentClient::Error)));
+    connect(client, &TorrentClient::stateChanged,
+            this, &MainWindow::updateState);
+    connect(client, &TorrentClient::peerInfoUpdated,
+            this, &MainWindow::updatePeerInfo);
+    connect(client, &TorrentClient::progressUpdated,
+            this, &MainWindow::updateProgress);
+    connect(client, &TorrentClient::downloadRateUpdated,
+            this, &MainWindow::updateDownloadRate);
+    connect(client, &TorrentClient::uploadRateUpdated,
+            this, &MainWindow::updateUploadRate);
+    connect(client, &TorrentClient::stopped,
+            this, &MainWindow::torrentStopped);
+    connect(client, QOverload<TorrentClient::Error>::of(&TorrentClient::error),
+            this, &MainWindow::torrentError);
 
     // Add the client to the list of downloading jobs.
     Job job;
@@ -414,7 +422,7 @@ bool MainWindow::addTorrent(const QString &fileName, const QString &destinationF
 
     if (!saveChanges) {
         saveChanges = true;
-        QTimer::singleShot(5000, this, SLOT(saveSettings()));
+        QTimer::singleShot(5000, this, &MainWindow::saveSettings);
     }
     client->start();
     return true;
@@ -491,15 +499,15 @@ void MainWindow::setActionsEnabled()
 {
     // Find the view item and client for the current row, and update
     // the states of the actions.
-    QTreeWidgetItem *item = 0;
+    QTreeWidgetItem *item = nullptr;
     if (!torrentView->selectedItems().isEmpty())
         item = torrentView->selectedItems().first();
-    TorrentClient *client = item ? jobs.at(torrentView->indexOfTopLevelItem(item)).client : 0;
+    TorrentClient *client = item ? jobs.at(torrentView->indexOfTopLevelItem(item)).client : nullptr;
     bool pauseEnabled = client && ((client->state() == TorrentClient::Paused)
                                        ||  (client->state() > TorrentClient::Preparing));
 
-    removeTorrentAction->setEnabled(item != 0);
-    pauseTorrentAction->setEnabled(item != 0 && pauseEnabled);
+    removeTorrentAction->setEnabled(item != nullptr);
+    pauseTorrentAction->setEnabled(item && pauseEnabled);
 
     if (client && client->state() == TorrentClient::Paused) {
         pauseTorrentAction->setIcon(QIcon(":/icons/player_play.png"));
@@ -524,7 +532,7 @@ void MainWindow::updateDownloadRate(int bytesPerSecond)
 
     if (!saveChanges) {
         saveChanges = true;
-        QTimer::singleShot(5000, this, SLOT(saveSettings()));
+        QTimer::singleShot(5000, this, &MainWindow::saveSettings);
     }
 }
 
@@ -538,7 +546,7 @@ void MainWindow::updateUploadRate(int bytesPerSecond)
 
     if (!saveChanges) {
         saveChanges = true;
-        QTimer::singleShot(5000, this, SLOT(saveSettings()));
+        QTimer::singleShot(5000, this, &MainWindow::saveSettings);
     }
 }
 
@@ -649,7 +657,7 @@ void MainWindow::about()
     about.setWindowTitle(tr("About Torrent Client"));
     about.setLayout(mainLayout);
 
-    connect(quitButton, SIGNAL(clicked()), &about, SLOT(close()));
+    connect(quitButton, &QPushButton::clicked, &about, &QDialog::close);
 
     about.exec();
 }
@@ -688,7 +696,7 @@ void MainWindow::closeEvent(QCloseEvent *)
         ++jobsToStop;
         TorrentClient *client = job.client;
         client->disconnect();
-        connect(client, SIGNAL(stopped()), this, SLOT(torrentStopped()));
+        connect(client, &TorrentClient::stopped, this, &MainWindow::torrentStopped);
         client->stop();
         delete torrentView->takeTopLevelItem(0);
     }
@@ -696,7 +704,7 @@ void MainWindow::closeEvent(QCloseEvent *)
     if (jobsToStop > jobsStopped)
         quitDialog->exec();
     quitDialog->deleteLater();
-    quitDialog = 0;
+    quitDialog = nullptr;
 }
 
 TorrentView::TorrentView(QWidget *parent)
diff --git a/examples/network/torrent/mainwindow.h b/examples/network/torrent/mainwindow.h
index 9c55b72256..78542b535b 100644
--- a/examples/network/torrent/mainwindow.h
+++ b/examples/network/torrent/mainwindow.h
@@ -71,7 +71,7 @@ class MainWindow : public QMainWindow
     Q_OBJECT
 
 public:
-    MainWindow(QWidget *parent = 0);
+    MainWindow(QWidget *parent = nullptr);
 
     QSize sizeHint() const override;
     const TorrentClient *clientForRow(int row) const;
diff --git a/examples/network/torrent/peerwireclient.cpp b/examples/network/torrent/peerwireclient.cpp
index 7a53c85f0c..cea4ef53fa 100644
--- a/examples/network/torrent/peerwireclient.cpp
+++ b/examples/network/torrent/peerwireclient.cpp
@@ -87,7 +87,7 @@ PeerWireClient::PeerWireClient(const QByteArray &peerId, QObject *parent)
     : QTcpSocket(parent), pendingBlockSizes(0),
       pwState(ChokingPeer | ChokedByPeer), receivedHandShake(false), gotPeerId(false),
       sentHandShake(false), nextPacketLength(-1), pendingRequestTimer(0), invalidateTimeout(false),
-      keepAliveTimer(0), torrentPeer(0)
+      keepAliveTimer(0), torrentPeer(nullptr)
 {
     memset(uploadSpeedData, 0, sizeof(uploadSpeedData));
     memset(downloadSpeedData, 0, sizeof(downloadSpeedData));
@@ -96,21 +96,23 @@ PeerWireClient::PeerWireClient(const QByteArray &peerId, QObject *parent)
     timeoutTimer = startTimer(ConnectTimeout);
     peerIdString = peerId;
 
-    connect(this, SIGNAL(readyRead()), this, SIGNAL(readyToTransfer()));
-    connect(this, SIGNAL(connected()), this, SIGNAL(readyToTransfer()));
-
-    connect(&socket, SIGNAL(connected()),
-            this, SIGNAL(connected()));
-    connect(&socket, SIGNAL(readyRead()),
-            this, SIGNAL(readyRead()));
-    connect(&socket, SIGNAL(disconnected()),
-            this, SIGNAL(disconnected()));
-    connect(&socket, SIGNAL(error(QAbstractSocket::SocketError)),
-            this, SIGNAL(error(QAbstractSocket::SocketError)));
-    connect(&socket, SIGNAL(bytesWritten(qint64)),
-            this, SIGNAL(bytesWritten(qint64)));
-    connect(&socket, SIGNAL(stateChanged(QAbstractSocket::SocketState)),
-            this, SLOT(socketStateChanged(QAbstractSocket::SocketState)));
+    connect(this, &PeerWireClient::readyRead,
+            this, &PeerWireClient::readyToTransfer);
+    connect(this, &PeerWireClient::connected,
+            this, &PeerWireClient::readyToTransfer);
+
+    connect(&socket, &QTcpSocket::connected,
+            this, &PeerWireClient::connected);
+    connect(&socket, &QTcpSocket::readyRead,
+            this, &PeerWireClient::readyRead);
+    connect(&socket, &QTcpSocket::disconnected,
+            this, &PeerWireClient::disconnected);
+    connect(&socket, QOverload<QAbstractSocket::SocketError>::of(&QTcpSocket::error),
+            this, QOverload<QAbstractSocket::SocketError>::of(&PeerWireClient::error));
+    connect(&socket, &QTcpSocket::bytesWritten,
+            this, &PeerWireClient::bytesWritten);
+    connect(&socket, &QTcpSocket::stateChanged,
+            this, &PeerWireClient::socketStateChanged);
 
 }
 
diff --git a/examples/network/torrent/peerwireclient.h b/examples/network/torrent/peerwireclient.h
index e03b538f63..75edf8ee77 100644
--- a/examples/network/torrent/peerwireclient.h
+++ b/examples/network/torrent/peerwireclient.h
@@ -92,7 +92,7 @@ public:
     };
     Q_DECLARE_FLAGS(PeerWireState, PeerWireStateFlag)
 
-    explicit PeerWireClient(const QByteArray &peerId, QObject *parent = 0);
+    explicit PeerWireClient(const QByteArray &peerId, QObject *parent = nullptr);
     void initialize(const QByteArray &infoHash, int pieceCount);
 
     void setPeer(TorrentPeer *peer);
diff --git a/examples/network/torrent/ratecontroller.cpp b/examples/network/torrent/ratecontroller.cpp
index 96474806f5..756947b65c 100644
--- a/examples/network/torrent/ratecontroller.cpp
+++ b/examples/network/torrent/ratecontroller.cpp
@@ -62,7 +62,8 @@ RateController *RateController::instance()
 
 void RateController::addSocket(PeerWireClient *socket)
 {
-    connect(socket, SIGNAL(readyToTransfer()), this, SLOT(scheduleTransfer()));
+    connect(socket, &PeerWireClient::readyToTransfer,
+            this, &RateController::scheduleTransfer);
     socket->setReadBufferSize(downLimit * 4);
     sockets << socket;
     scheduleTransfer();
@@ -70,7 +71,8 @@ void RateController::addSocket(PeerWireClient *socket)
 
 void RateController::removeSocket(PeerWireClient *socket)
 {
-    disconnect(socket, SIGNAL(readyToTransfer()), this, SLOT(scheduleTransfer()));
+    disconnect(socket, &PeerWireClient::readyToTransfer,
+               this, &RateController::scheduleTransfer);
     socket->setReadBufferSize(0);
     sockets.remove(socket);
 }
diff --git a/examples/network/torrent/ratecontroller.h b/examples/network/torrent/ratecontroller.h
index f8bff0cc36..593a76f592 100644
--- a/examples/network/torrent/ratecontroller.h
+++ b/examples/network/torrent/ratecontroller.h
@@ -62,8 +62,7 @@ class RateController : public QObject
     Q_OBJECT
 
 public:
-    inline RateController(QObject *parent = 0)
-        : QObject(parent), transferScheduled(false) { }
+    using QObject::QObject;
     static RateController *instance();
 
     void addSocket(PeerWireClient *socket);
@@ -81,9 +80,9 @@ public slots:
 private:
     QElapsedTimer stopWatch;
     QSet<PeerWireClient *> sockets;
-    int upLimit;
-    int downLimit;
-    bool transferScheduled;
+    int upLimit = 0;
+    int downLimit = 0;
+    bool transferScheduled = false;
 };
 
 #endif
diff --git a/examples/network/torrent/torrentclient.cpp b/examples/network/torrent/torrentclient.cpp
index bddf3caa1a..6b11338f42 100644
--- a/examples/network/torrent/torrentclient.cpp
+++ b/examples/network/torrent/torrentclient.cpp
@@ -75,13 +75,12 @@ static const int MinimumTimeBeforeRevisit = 30;
 static const int MaxUploads = 4;
 static const int UploadScheduleInterval = 10000;
 
-class TorrentPiece {
-public:
-    int index;
-    int length;
+struct TorrentPiece {
     QBitArray completedBlocks;
     QBitArray requestedBlocks;
-    bool inProgress;
+    int index = 0;
+    int length = 0;
+    bool inProgress = false;
 };
 
 class TorrentClientPrivate
@@ -227,7 +226,7 @@ void TorrentClientPrivate::callPeerConnector()
 {
     if (!connectingToClients) {
         connectingToClients = true;
-        QTimer::singleShot(10000, q, SLOT(connectToPeers()));
+        QTimer::singleShot(10000, q, &TorrentClient::connectToPeers);
     }
 }
 
@@ -235,22 +234,22 @@ TorrentClient::TorrentClient(QObject *parent)
     : QObject(parent), d(new TorrentClientPrivate(this))
 {
     // Connect the file manager
-    connect(&d->fileManager, SIGNAL(dataRead(int,int,int,QByteArray)),
-            this, SLOT(sendToPeer(int,int,int,QByteArray)));
-    connect(&d->fileManager, SIGNAL(verificationProgress(int)),
-            this, SLOT(updateProgress(int)));
-    connect(&d->fileManager, SIGNAL(verificationDone()),
-            this, SLOT(fullVerificationDone()));
-    connect(&d->fileManager, SIGNAL(pieceVerified(int,bool)),
-            this, SLOT(pieceVerified(int,bool)));
-    connect(&d->fileManager, SIGNAL(error()),
-            this, SLOT(handleFileError()));
+    connect(&d->fileManager, &FileManager::dataRead,
+            this, &TorrentClient::sendToPeer);
+    connect(&d->fileManager, &FileManager::verificationProgress,
+            this, &TorrentClient::updateProgress);
+    connect(&d->fileManager, &FileManager::verificationDone,
+            this, &TorrentClient::fullVerificationDone);
+    connect(&d->fileManager, &FileManager::pieceVerified,
+            this, &TorrentClient::pieceVerified);
+    connect(&d->fileManager, &FileManager::error,
+            this, &TorrentClient::handleFileError);
 
     // Connect the tracker client
-    connect(&d->trackerClient, SIGNAL(peerListUpdated(QList<TorrentPeer>)),
-            this, SLOT(addToPeerList(QList<TorrentPeer>)));
-    connect(&d->trackerClient, SIGNAL(stopped()),
-            this, SIGNAL(stopped()));
+    connect(&d->trackerClient, &TrackerClient::peerListUpdated,
+            this, &TorrentClient::addToPeerList);
+    connect(&d->trackerClient, &TrackerClient::stopped,
+            this, &TorrentClient::stopped);
 }
 
 TorrentClient::~TorrentClient()
@@ -840,26 +839,26 @@ void TorrentClient::setupOutgoingConnection()
 
 void TorrentClient::initializeConnection(PeerWireClient *client)
 {
-    connect(client, SIGNAL(connected()),
-            this, SLOT(setupOutgoingConnection()));
-    connect(client, SIGNAL(disconnected()),
-            this, SLOT(removeClient()));
-    connect(client, SIGNAL(error(QAbstractSocket::SocketError)),
-            this, SLOT(removeClient()));
-    connect(client, SIGNAL(piecesAvailable(QBitArray)),
-            this, SLOT(peerPiecesAvailable(QBitArray)));
-    connect(client, SIGNAL(blockRequested(int,int,int)),
-            this, SLOT(peerRequestsBlock(int,int,int)));
-    connect(client, SIGNAL(blockReceived(int,int,QByteArray)),
-            this, SLOT(blockReceived(int,int,QByteArray)));
-    connect(client, SIGNAL(choked()),
-            this, SLOT(peerChoked()));
-    connect(client, SIGNAL(unchoked()),
-            this, SLOT(peerUnchoked()));
-    connect(client, SIGNAL(bytesWritten(qint64)),
-            this, SLOT(peerWireBytesWritten(qint64)));
-    connect(client, SIGNAL(bytesReceived(qint64)),
-            this, SLOT(peerWireBytesReceived(qint64)));
+    connect(client, &PeerWireClient::connected,
+            this, &TorrentClient::setupOutgoingConnection);
+    connect(client, &PeerWireClient::disconnected,
+            this, &TorrentClient::removeClient);
+    connect(client, QOverload<QAbstractSocket::SocketError>::of(&PeerWireClient::error),
+            this, &TorrentClient::removeClient);
+    connect(client, &PeerWireClient::piecesAvailable,
+            this, &TorrentClient::peerPiecesAvailable);
+    connect(client, &PeerWireClient::blockRequested,
+            this, &TorrentClient::peerRequestsBlock);
+    connect(client, &PeerWireClient::blockReceived,
+            this, &TorrentClient::blockReceived);
+    connect(client, &PeerWireClient::choked,
+            this, &TorrentClient::peerChoked);
+    connect(client, &PeerWireClient::unchoked,
+            this, &TorrentClient::peerUnchoked);
+    connect(client, &PeerWireClient::bytesWritten,
+            this, &TorrentClient::peerWireBytesWritten);
+    connect(client, &PeerWireClient::bytesReceived,
+            this, &TorrentClient::peerWireBytesReceived);
 }
 
 void TorrentClient::removeClient()
@@ -890,7 +889,8 @@ void TorrentClient::removeClient()
     }
 
     // Delete the client later.
-    disconnect(client, SIGNAL(disconnected()), this, SLOT(removeClient()));
+    disconnect(client, &PeerWireClient::disconnected,
+               this, &TorrentClient::removeClient);
     client->deleteLater();
     ConnectionManager::instance()->removeConnection(client);
 
@@ -905,7 +905,7 @@ void TorrentClient::peerPiecesAvailable(const QBitArray &pieces)
     // Find the peer in our list of announced peers. If it's there,
     // then we can use the piece list into to gather statistics that
     // help us decide what peers to connect to.
-    TorrentPeer *peer = 0;
+    TorrentPeer *peer = nullptr;
     QList<TorrentPeer *>::Iterator it = d->peers.begin();
     while (it != d->peers.end()) {
         if ((*it)->address == client->peerAddress() && (*it)->port == client->peerPort()) {
@@ -1163,7 +1163,7 @@ void TorrentClient::schedulePieceForClient(PeerWireClient *client)
     // many blocks have been requested.
     QList<int> currentPieces;
     bool somePiecesAreNotInProgress = false;
-    TorrentPiece *lastPendingPiece = 0;
+    TorrentPiece *lastPendingPiece = nullptr;
     QMultiMap<PeerWireClient *, TorrentPiece *>::Iterator it = d->payloads.find(client);
     while (it != d->payloads.end() && it.key() == client) {
         lastPendingPiece = it.value();
@@ -1183,7 +1183,7 @@ void TorrentClient::schedulePieceForClient(PeerWireClient *client)
     // If all pieces are in progress, but we haven't filled up our
     // block requesting quota, then we need to schedule another piece.
     if (!somePiecesAreNotInProgress || client->incomingBlocks().size() > 0)
-        lastPendingPiece = 0;
+        lastPendingPiece = nullptr;
     TorrentPiece *piece = lastPendingPiece;
 
     // In warmup state, all clients request blocks from the same pieces.
diff --git a/examples/network/torrent/torrentclient.h b/examples/network/torrent/torrentclient.h
index b9b88b3a07..ad77caa66c 100644
--- a/examples/network/torrent/torrentclient.h
+++ b/examples/network/torrent/torrentclient.h
@@ -58,8 +58,7 @@
 class MetaInfo;
 class PeerWireClient;
 class TorrentClientPrivate;
-class TorrentPeer;
-class TorrentPiece;
+struct TorrentPiece;
 QT_BEGIN_NAMESPACE
 class QTimerEvent;
 QT_END_NAMESPACE
@@ -110,7 +109,7 @@ public:
         ServerError
     };
 
-    TorrentClient(QObject *parent = 0);
+    TorrentClient(QObject *parent = nullptr);
     ~TorrentClient();
 
     bool setTorrent(const QString &fileName);
diff --git a/examples/network/torrent/torrentserver.cpp b/examples/network/torrent/torrentserver.cpp
index c68f33249c..215498194b 100644
--- a/examples/network/torrent/torrentserver.cpp
+++ b/examples/network/torrent/torrentserver.cpp
@@ -78,10 +78,10 @@ void TorrentServer::incomingConnection(qintptr socketDescriptor)
 
     if (client->setSocketDescriptor(socketDescriptor)) {
         if (ConnectionManager::instance()->canAddConnection() && !clients.isEmpty()) {
-            connect(client, SIGNAL(infoHashReceived(QByteArray)),
-                    this, SLOT(processInfoHash(QByteArray)));
-            connect(client, SIGNAL(error(QAbstractSocket::SocketError)),
-                    this, SLOT(removeClient()));
+            connect(client, &PeerWireClient::infoHashReceived,
+                    this, &TorrentServer::processInfoHash);
+            connect(client, QOverload<QAbstractSocket::SocketError>::of(&PeerWireClient::error),
+                    this, QOverload<>::of(&TorrentServer::removeClient));
             RateController::instance()->addSocket(client);
             ConnectionManager::instance()->addConnection(client);
             return;
@@ -104,7 +104,7 @@ void TorrentServer::processInfoHash(const QByteArray &infoHash)
     PeerWireClient *peer = qobject_cast<PeerWireClient *>(sender());
     for (TorrentClient *client : qAsConst(clients)) {
         if (client->state() >= TorrentClient::Searching && client->infoHash() == infoHash) {
-            peer->disconnect(peer, 0, this, 0);
+            peer->disconnect(peer, nullptr, this, nullptr);
             client->setupIncomingConnection(peer);
             return;
         }
diff --git a/examples/network/torrent/trackerclient.cpp b/examples/network/torrent/trackerclient.cpp
index e883317b12..00810a98af 100644
--- a/examples/network/torrent/trackerclient.cpp
+++ b/examples/network/torrent/trackerclient.cpp
@@ -60,14 +60,8 @@
 TrackerClient::TrackerClient(TorrentClient *downloader, QObject *parent)
     : QObject(parent), torrentDownloader(downloader)
 {
-    length = 0;
-    requestInterval = 5 * 60;
-    requestIntervalTimer = -1;
-    firstTrackerRequest = true;
-    lastTrackerRequest = false;
-    firstSeeding = true;
-
-    connect(&http, SIGNAL(finished(QNetworkReply*)), this, SLOT(httpRequestDone(QNetworkReply*)));
+    connect(&http, &QNetworkAccessManager::finished,
+            this, &TrackerClient::httpRequestDone);
 }
 
 void TrackerClient::start(const MetaInfo &info)
@@ -157,8 +151,8 @@ void TrackerClient::fetchPeerList()
     if (!url.userName().isEmpty()) {
         uname = url.userName();
         pwd = url.password();
-        connect(&http, SIGNAL(authenticationRequired(QNetworkReply*,QAuthenticator*)),
-                this, SLOT(provideAuthentication(QNetworkReply*,QAuthenticator*)));
+        connect(&http, &QNetworkAccessManager::authenticationRequired,
+                this, &TrackerClient::provideAuthentication);
     }
     http.get(req);
 }
diff --git a/examples/network/torrent/trackerclient.h b/examples/network/torrent/trackerclient.h
index 323fc67eba..b8c169ff22 100644
--- a/examples/network/torrent/trackerclient.h
+++ b/examples/network/torrent/trackerclient.h
@@ -69,7 +69,7 @@ class TrackerClient : public QObject
     Q_OBJECT
 
 public:
-    explicit TrackerClient(TorrentClient *downloader, QObject *parent = 0);
+    explicit TrackerClient(TorrentClient *downloader, QObject *parent = nullptr);
 
     void start(const MetaInfo &info);
     void stop();
@@ -98,21 +98,19 @@ private slots:
 private:
     TorrentClient *torrentDownloader;
 
-    int requestInterval;
-    int requestIntervalTimer;
+    int requestInterval = 5 * 60;
+    int requestIntervalTimer = -1;
     QNetworkAccessManager http;
     MetaInfo metaInfo;
     QByteArray trackerId;
     QList<TorrentPeer> peers;
-    qint64 uploadedBytes;
-    qint64 downloadedBytes;
-    qint64 length;
+    qint64 length = 0;
     QString uname;
     QString pwd;
 
-    bool firstTrackerRequest;
-    bool lastTrackerRequest;
-    bool firstSeeding;
+    bool firstTrackerRequest = true;
+    bool lastTrackerRequest = false;
+    bool firstSeeding = true;
 };
 
 #endif