- Qt 5.5
- Qt Network
- Torrent Example
- mainwindow.cpp Example File
- Qt 5.5.1 Reference Documentation

# mainwindow.cpp Example File

torrent/mainwindow.cpp

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    ** This file is part of the examples of the Qt Toolkit.
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    #include <QtWidgets>

    #include "addtorrentdialog.h"
    #include "mainwindow.h"
    #include "ratecontroller.h"
    #include "torrentclient.h"

    // TorrentView extends QTreeWidget to allow drag and drop.
    class TorrentView : public QTreeWidget
    {
        Q_OBJECT
    public:
        TorrentView(QWidget *parent = 0);

    #ifndef QT_NO_DRAGANDDROP
    signals:
        void fileDropped(const QString &fileName);

    protected:
        void dragMoveEvent(QDragMoveEvent *event) Q_DECL_OVERRIDE;
        void dropEvent(QDropEvent *event) Q_DECL_OVERRIDE;
    #endif
    };

    // TorrentViewDelegate is used to draw the progress bars.
    class TorrentViewDelegate : public QItemDelegate
    {
        Q_OBJECT
    public:
        inline TorrentViewDelegate(MainWindow *mainWindow) : QItemDelegate(mainWindow) {}

        void paint(QPainter *painter, const QStyleOptionViewItem &option,
                   const QModelIndex &index ) const Q_DECL_OVERRIDE
        {
            if (index.column() != 2) {
                QItemDelegate::paint(painter, option, index);
                return;
            }

            // Set up a QStyleOptionProgressBar to precisely mimic the
            // environment of a progress bar.
            QStyleOptionProgressBar progressBarOption;
            progressBarOption.state = QStyle::State_Enabled;
            progressBarOption.direction = QApplication::layoutDirection();
            progressBarOption.rect = option.rect;
            progressBarOption.fontMetrics = QApplication::fontMetrics();
            progressBarOption.minimum = 0;
            progressBarOption.maximum = 100;
            progressBarOption.textAlignment = Qt::AlignCenter;
            progressBarOption.textVisible = true;

            // Set the progress and text values of the style option.
            int progress = qobject_cast<MainWindow *>(parent())->clientForRow(index.row())->progress();
            progressBarOption.progress = progress < 0 ? 0 : progress;
            progressBarOption.text = QString::asprintf("%d%%", progressBarOption.progress);

            // Draw the progress bar onto the view.
            QApplication::style()->drawControl(QStyle::CE_ProgressBar, &progressBarOption, painter);
        }
    };

    MainWindow::MainWindow(QWidget *parent)
        : QMainWindow(parent), quitDialog(0), saveChanges(false)
    {
        // Initialize some static strings
        QStringList headers;
        headers << tr("Torrent") << tr("Peers/Seeds") << tr("Progress")
                << tr("Down rate") << tr("Up rate") << tr("Status");

        // Main torrent list
        torrentView = new TorrentView(this);
        torrentView->setItemDelegate(new TorrentViewDelegate(this));
        torrentView->setHeaderLabels(headers);
        torrentView->setSelectionBehavior(QAbstractItemView::SelectRows);
        torrentView->setAlternatingRowColors(true);
        torrentView->setRootIsDecorated(false);
        setCentralWidget(torrentView);

        // Set header resize modes and initial section sizes
        QFontMetrics fm = fontMetrics();
        QHeaderView *header = torrentView->header();
        header->resizeSection(0, fm.width("typical-name-for-a-torrent.torrent"));
        header->resizeSection(1, fm.width(headers.at(1) + "  "));
        header->resizeSection(2, fm.width(headers.at(2) + "  "));
        header->resizeSection(3, qMax(fm.width(headers.at(3) + "  "), fm.width(" 1234.0 KB/s ")));
        header->resizeSection(4, qMax(fm.width(headers.at(4) + "  "), fm.width(" 1234.0 KB/s ")));
        header->resizeSection(5, qMax(fm.width(headers.at(5) + "  "), fm.width(tr("Downloading") + "  ")));

        // Create common actions
        QAction *newTorrentAction = new QAction(QIcon(":/icons/bottom.png"), tr("Add &new torrent"), this);
        pauseTorrentAction = new QAction(QIcon(":/icons/player_pause.png"), tr("&Pause torrent"), this);
        removeTorrentAction = new QAction(QIcon(":/icons/player_stop.png"), tr("&Remove torrent"), this);

        // File menu
        QMenu *fileMenu = menuBar()->addMenu(tr("&File"));
        fileMenu->addAction(newTorrentAction);
        fileMenu->addAction(pauseTorrentAction);
        fileMenu->addAction(removeTorrentAction);
        fileMenu->addSeparator();
        fileMenu->addAction(QIcon(":/icons/exit.png"), tr("E&xit"), this, SLOT(close()));

        // Help menu
        QMenu *helpMenu = menuBar()->addMenu(tr("&Help"));
        helpMenu->addAction(tr("&About"), this, SLOT(about()));
        helpMenu->addAction(tr("About &Qt"), qApp, SLOT(aboutQt()));

        // Top toolbar
        QToolBar *topBar = new QToolBar(tr("Tools"));
        addToolBar(Qt::TopToolBarArea, topBar);
        topBar->setMovable(false);
        topBar->addAction(newTorrentAction);
        topBar->addAction(removeTorrentAction);
        topBar->addAction(pauseTorrentAction);
        topBar->addSeparator();
        downActionTool = topBar->addAction(QIcon(tr(":/icons/1downarrow.png")), tr("Move down"));
        upActionTool = topBar->addAction(QIcon(tr(":/icons/1uparrow.png")), tr("Move up"));

        // Bottom toolbar
        QToolBar *bottomBar = new QToolBar(tr("Rate control"));
        addToolBar(Qt::BottomToolBarArea, bottomBar);
        bottomBar->setMovable(false);
        downloadLimitSlider = new QSlider(Qt::Horizontal);
        downloadLimitSlider->setRange(0, 1000);
        bottomBar->addWidget(new QLabel(tr("Max download:")));
        bottomBar->addWidget(downloadLimitSlider);
        bottomBar->addWidget((downloadLimitLabel = new QLabel(tr("0 KB/s"))));
        downloadLimitLabel->setFixedSize(QSize(fm.width(tr("99999 KB/s")), fm.lineSpacing()));
        bottomBar->addSeparator();
        uploadLimitSlider = new QSlider(Qt::Horizontal);
        uploadLimitSlider->setRange(0, 1000);
        bottomBar->addWidget(new QLabel(tr("Max upload:")));
        bottomBar->addWidget(uploadLimitSlider);
        bottomBar->addWidget((uploadLimitLabel = new QLabel(tr("0 KB/s"))));
        uploadLimitLabel->setFixedSize(QSize(fm.width(tr("99999 KB/s")), fm.lineSpacing()));

    #ifdef Q_OS_OSX
        setUnifiedTitleAndToolBarOnMac(true);
    #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()));

        // Load settings and start
        setWindowTitle(tr("Torrent Client"));
        setActionsEnabled();
        QMetaObject::invokeMethod(this, "loadSettings", Qt::QueuedConnection);
    }

    QSize MainWindow::sizeHint() const
    {
        const QHeaderView *header = torrentView->header();

        // Add up the sizes of all header sections. The last section is
        // stretched, so its size is relative to the size of the width;
        // instead of counting it, we count the size of its largest value.
        int width = fontMetrics().width(tr("Downloading") + "  ");
        for (int i = 0; i < header->count() - 1; ++i)
            width += header->sectionSize(i);

        return QSize(width, QMainWindow::sizeHint().height())
            .expandedTo(QApplication::globalStrut());
    }

    const TorrentClient *MainWindow::clientForRow(int row) const
    {
        // Return the client at the given row.
        return jobs.at(row).client;
    }

    int MainWindow::rowOfClient(TorrentClient *client) const
    {
        // Return the row that displays this client's status, or -1 if the
        // client is not known.
        int row = 0;
        foreach (Job job, jobs) {
            if (job.client == client)
                return row;
            ++row;
        }
        return -1;
    }

    void MainWindow::loadSettings()
    {
        // Load base settings (last working directory, upload/download limits).
        QSettings settings("QtProject", "Torrent");
        lastDirectory = settings.value("LastDirectory").toString();
        if (lastDirectory.isEmpty())
            lastDirectory = QDir::currentPath();
        int up = settings.value("UploadLimit").toInt();
        int down = settings.value("DownloadLimit").toInt();
        uploadLimitSlider->setValue(up ? up : 170);
        downloadLimitSlider->setValue(down ? down : 550);

        // Resume all previous downloads.
        int size = settings.beginReadArray("Torrents");
        for (int i = 0; i < size; ++i) {
            settings.setArrayIndex(i);
            QByteArray resumeState = settings.value("resumeState").toByteArray();
            QString fileName = settings.value("sourceFileName").toString();
            QString dest = settings.value("destinationFolder").toString();

            if (addTorrent(fileName, dest, resumeState)) {
                TorrentClient *client = jobs.last().client;
                client->setDownloadedBytes(settings.value("downloadedBytes").toLongLong());
                client->setUploadedBytes(settings.value("uploadedBytes").toLongLong());
            }
        }
    }

    bool MainWindow::addTorrent()
    {
        // Show the file dialog, let the user select what torrent to start downloading.
        QString fileName = QFileDialog::getOpenFileName(this, tr("Choose a torrent file"),
                                                        lastDirectory,
                                                        tr("Torrents (*.torrent);;"
                                                           " All files (*.*)"));
        if (fileName.isEmpty())
            return false;
        lastDirectory = QFileInfo(fileName).absolutePath();

        // Show the "Add Torrent" dialog.
        AddTorrentDialog *addTorrentDialog = new AddTorrentDialog(this);
        addTorrentDialog->setTorrent(fileName);
        addTorrentDialog->deleteLater();
        if (!addTorrentDialog->exec())
            return false;

        // Add the torrent to our list of downloads
        addTorrent(fileName, addTorrentDialog->destinationFolder());
        if (!saveChanges) {
            saveChanges = true;
            QTimer::singleShot(1000, this, SLOT(saveSettings()));
        }
        return true;
    }

    void MainWindow::removeTorrent()
    {
        // Find the row of the current item, and find the torrent client
        // for that row.
        int row = torrentView->indexOfTopLevelItem(torrentView->currentItem());
        TorrentClient *client = jobs.at(row).client;

        // Stop the client.
        client->disconnect();
        connect(client, SIGNAL(stopped()), this, SLOT(torrentStopped()));
        client->stop();

        // Remove the row from the view.
        delete torrentView->takeTopLevelItem(row);
        jobs.removeAt(row);
        setActionsEnabled();

        saveChanges = true;
        saveSettings();
    }

    void MainWindow::torrentStopped()
    {
        // Schedule the client for deletion.
        TorrentClient *client = qobject_cast<TorrentClient *>(sender());
        client->deleteLater();

        // If the quit dialog is shown, update its progress.
        if (quitDialog) {
            if (++jobsStopped == jobsToStop)
                quitDialog->close();
        }
    }

    void MainWindow::torrentError(TorrentClient::Error)
    {
        // Delete the client.
        TorrentClient *client = qobject_cast<TorrentClient *>(sender());
        int row = rowOfClient(client);
        QString fileName = jobs.at(row).torrentFileName;
        jobs.removeAt(row);

        // Display the warning.
        QMessageBox::warning(this, tr("Error"),
                             tr("An error occurred while downloading %0: %1")
                             .arg(fileName)
                             .arg(client->errorString()));

        delete torrentView->takeTopLevelItem(row);
        client->deleteLater();
    }

    bool MainWindow::addTorrent(const QString &fileName, const QString &destinationFolder,
                                const QByteArray &resumeState)
    {
        // Check if the torrent is already being downloaded.
        foreach (Job job, jobs) {
            if (job.torrentFileName == fileName && job.destinationDirectory == destinationFolder) {
                QMessageBox::warning(this, tr("Already downloading"),
                                     tr("The torrent file %1 is "
                                        "already being downloaded.").arg(fileName));
                return false;
            }
        }

        // Create a new torrent client and attempt to parse the torrent data.
        TorrentClient *client = new TorrentClient(this);
        if (!client->setTorrent(fileName)) {
            QMessageBox::warning(this, tr("Error"),
                                 tr("The torrent file %1 cannot not be opened/resumed.").arg(fileName));
            delete client;
            return false;
        }
        client->setDestinationFolder(destinationFolder);
        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)));

        // Add the client to the list of downloading jobs.
        Job job;
        job.client = client;
        job.torrentFileName = fileName;
        job.destinationDirectory = destinationFolder;
        jobs << job;

        // Create and add a row in the torrent view for this download.
        QTreeWidgetItem *item = new QTreeWidgetItem(torrentView);

        QString baseFileName = QFileInfo(fileName).fileName();
        if (baseFileName.toLower().endsWith(".torrent"))
            baseFileName.remove(baseFileName.size() - 8);

        item->setText(0, baseFileName);
        item->setToolTip(0, tr("Torrent: %1<br>Destination: %2")
                         .arg(baseFileName).arg(destinationFolder));
        item->setText(1, tr("0/0"));
        item->setText(2, "0");
        item->setText(3, "0.0 KB/s");
        item->setText(4, "0.0 KB/s");
        item->setText(5, tr("Idle"));
        item->setFlags(item->flags() & ~Qt::ItemIsEditable);
        item->setTextAlignment(1, Qt::AlignHCenter);

        if (!saveChanges) {
            saveChanges = true;
            QTimer::singleShot(5000, this, SLOT(saveSettings()));
        }
        client->start();
        return true;
    }

    void MainWindow::saveSettings()
    {
        if (!saveChanges)
          return;
        saveChanges = false;

        // Prepare and reset the settings
        QSettings settings("QtProject", "Torrent");
        settings.clear();

        settings.setValue("LastDirectory", lastDirectory);
        settings.setValue("UploadLimit", uploadLimitSlider->value());
        settings.setValue("DownloadLimit", downloadLimitSlider->value());

        // Store data on all known torrents
        settings.beginWriteArray("Torrents");
        for (int i = 0; i < jobs.size(); ++i) {
            settings.setArrayIndex(i);
            settings.setValue("sourceFileName", jobs.at(i).torrentFileName);
            settings.setValue("destinationFolder", jobs.at(i).destinationDirectory);
            settings.setValue("uploadedBytes", jobs.at(i).client->uploadedBytes());
            settings.setValue("downloadedBytes", jobs.at(i).client->downloadedBytes());
            settings.setValue("resumeState", jobs.at(i).client->dumpedState());
        }
        settings.endArray();
        settings.sync();
    }

    void MainWindow::updateState(TorrentClient::State)
    {
        // Update the state string whenever the client's state changes.
        TorrentClient *client = qobject_cast<TorrentClient *>(sender());
        int row = rowOfClient(client);
        QTreeWidgetItem *item = torrentView->topLevelItem(row);
        if (item) {
            item->setToolTip(0, tr("Torrent: %1<br>Destination: %2<br>State: %3")
                             .arg(jobs.at(row).torrentFileName)
                             .arg(jobs.at(row).destinationDirectory)
                             .arg(client->stateString()));

            item->setText(5, client->stateString());
        }
        setActionsEnabled();
    }

    void MainWindow::updatePeerInfo()
    {
        // Update the number of connected, visited, seed and leecher peers.
        TorrentClient *client = qobject_cast<TorrentClient *>(sender());
        int row = rowOfClient(client);

        QTreeWidgetItem *item = torrentView->topLevelItem(row);
        item->setText(1, tr("%1/%2").arg(client->connectedPeerCount())
                      .arg(client->seedCount()));
    }

    void MainWindow::updateProgress(int percent)
    {
        TorrentClient *client = qobject_cast<TorrentClient *>(sender());
        int row = rowOfClient(client);

        // Update the progressbar.
        QTreeWidgetItem *item = torrentView->topLevelItem(row);
        if (item)
            item->setText(2, QString::number(percent));
    }

    void MainWindow::setActionsEnabled()
    {
        // Find the view item and client for the current row, and update
        // the states of the actions.
        QTreeWidgetItem *item = 0;
        if (!torrentView->selectedItems().isEmpty())
            item = torrentView->selectedItems().first();
        TorrentClient *client = item ? jobs.at(torrentView->indexOfTopLevelItem(item)).client : 0;
        bool pauseEnabled = client && ((client->state() == TorrentClient::Paused)
                                           ||  (client->state() > TorrentClient::Preparing));

        removeTorrentAction->setEnabled(item != 0);
        pauseTorrentAction->setEnabled(item != 0 && pauseEnabled);

        if (client && client->state() == TorrentClient::Paused) {
            pauseTorrentAction->setIcon(QIcon(":/icons/player_play.png"));
            pauseTorrentAction->setText(tr("Resume torrent"));
        } else {
            pauseTorrentAction->setIcon(QIcon(":/icons/player_pause.png"));
            pauseTorrentAction->setText(tr("Pause torrent"));
        }

        int row = torrentView->indexOfTopLevelItem(item);
        upActionTool->setEnabled(item && row != 0);
        downActionTool->setEnabled(item && row != jobs.size() - 1);
    }

    void MainWindow::updateDownloadRate(int bytesPerSecond)
    {
        // Update the download rate.
        TorrentClient *client = qobject_cast<TorrentClient *>(sender());
        int row = rowOfClient(client);
        const QString num = QString::asprintf("%.1f KB/s", bytesPerSecond / 1024.0);
        torrentView->topLevelItem(row)->setText(3, num);

        if (!saveChanges) {
            saveChanges = true;
            QTimer::singleShot(5000, this, SLOT(saveSettings()));
        }
    }

    void MainWindow::updateUploadRate(int bytesPerSecond)
    {
        // Update the upload rate.
        TorrentClient *client = qobject_cast<TorrentClient *>(sender());
        int row = rowOfClient(client);
        const QString num = QString::asprintf("%.1f KB/s", bytesPerSecond / 1024.0);
        torrentView->topLevelItem(row)->setText(4, num);

        if (!saveChanges) {
            saveChanges = true;
            QTimer::singleShot(5000, this, SLOT(saveSettings()));
        }
    }

    void MainWindow::pauseTorrent()
    {
        // Pause or unpause the current torrent.
        int row = torrentView->indexOfTopLevelItem(torrentView->currentItem());
        TorrentClient *client = jobs.at(row).client;
        client->setPaused(client->state() != TorrentClient::Paused);
        setActionsEnabled();
    }

    void MainWindow::moveTorrentUp()
    {
        QTreeWidgetItem *item = torrentView->currentItem();
        int row = torrentView->indexOfTopLevelItem(item);
        if (row == 0)
            return;

        Job tmp = jobs.at(row - 1);
        jobs[row - 1] = jobs[row];
        jobs[row] = tmp;

        QTreeWidgetItem *itemAbove = torrentView->takeTopLevelItem(row - 1);
        torrentView->insertTopLevelItem(row, itemAbove);
        setActionsEnabled();
    }

    void MainWindow::moveTorrentDown()
    {
        QTreeWidgetItem *item = torrentView->currentItem();
        int row = torrentView->indexOfTopLevelItem(item);
        if (row == jobs.size() - 1)
            return;

        Job tmp = jobs.at(row + 1);
        jobs[row + 1] = jobs[row];
        jobs[row] = tmp;

        QTreeWidgetItem *itemAbove = torrentView->takeTopLevelItem(row + 1);
        torrentView->insertTopLevelItem(row, itemAbove);
        setActionsEnabled();
    }

    static int rateFromValue(int value)
    {
        int rate = 0;
        if (value >= 0 && value < 250) {
            rate = 1 + int(value * 0.124);
        } else if (value < 500) {
            rate = 32 + int((value - 250) * 0.384);
        } else if (value < 750) {
            rate = 128 + int((value - 500) * 1.536);
        } else {
            rate = 512 + int((value - 750) * 6.1445);
        }
        return rate;
    }

    void MainWindow::setUploadLimit(int value)
    {
        int rate = rateFromValue(value);
        uploadLimitLabel->setText(tr("%1 KB/s").arg(QString::asprintf("%4d", rate)));
        RateController::instance()->setUploadLimit(rate * 1024);
    }

    void MainWindow::setDownloadLimit(int value)
    {
        int rate = rateFromValue(value);
        downloadLimitLabel->setText(tr("%1 KB/s").arg(QString::asprintf("%4d", rate)));
        RateController::instance()->setDownloadLimit(rate * 1024);
    }

    void MainWindow::about()
    {
        QLabel *icon = new QLabel;
        icon->setPixmap(QPixmap(":/icons/peertopeer.png"));

        QLabel *text = new QLabel;
        text->setWordWrap(true);
        text->setText("<p>The <b>Torrent Client</b> example demonstrates how to"
                      " write a complete peer-to-peer file sharing"
                      " application using Qt's network and thread classes.</p>"
                      "<p>This feature complete client implementation of"
                      " the BitTorrent protocol can efficiently"
                      " maintain several hundred network connections"
                      " simultaneously.</p>");

        QPushButton *quitButton = new QPushButton("OK");

        QHBoxLayout *topLayout = new QHBoxLayout;
        topLayout->setMargin(10);
        topLayout->setSpacing(10);
        topLayout->addWidget(icon);
        topLayout->addWidget(text);

        QHBoxLayout *bottomLayout = new QHBoxLayout;
        bottomLayout->addStretch();
        bottomLayout->addWidget(quitButton);
        bottomLayout->addStretch();

        QVBoxLayout *mainLayout = new QVBoxLayout;
        mainLayout->addLayout(topLayout);
        mainLayout->addLayout(bottomLayout);

        QDialog about(this);
        about.setModal(true);
        about.setWindowTitle(tr("About Torrent Client"));
        about.setLayout(mainLayout);

        connect(quitButton, SIGNAL(clicked()), &about, SLOT(close()));

        about.exec();
    }

    void MainWindow::acceptFileDrop(const QString &fileName)
    {
        // Create and show the "Add Torrent" dialog.
        AddTorrentDialog *addTorrentDialog = new AddTorrentDialog;
        lastDirectory = QFileInfo(fileName).absolutePath();
        addTorrentDialog->setTorrent(fileName);
        addTorrentDialog->deleteLater();
        if (!addTorrentDialog->exec())
            return;

        // Add the torrent to our list of downloads.
        addTorrent(fileName, addTorrentDialog->destinationFolder());
        saveSettings();
    }

    void MainWindow::closeEvent(QCloseEvent *)
    {
        if (jobs.isEmpty())
            return;

        // Save upload / download numbers.
        saveSettings();
        saveChanges = false;

        quitDialog = new QProgressDialog(tr("Disconnecting from trackers"), tr("Abort"), 0, jobsToStop, this);

        // Stop all clients, remove the rows from the view and wait for
        // them to signal that they have stopped.
        jobsToStop = 0;
        jobsStopped = 0;
        foreach (Job job, jobs) {
            ++jobsToStop;
            TorrentClient *client = job.client;
            client->disconnect();
            connect(client, SIGNAL(stopped()), this, SLOT(torrentStopped()));
            client->stop();
            delete torrentView->takeTopLevelItem(0);
        }

        if (jobsToStop > jobsStopped)
            quitDialog->exec();
        quitDialog->deleteLater();
        quitDialog = 0;
    }

    TorrentView::TorrentView(QWidget *parent)
        : QTreeWidget(parent)
    {
    #ifndef QT_NO_DRAGANDDROP
        setAcceptDrops(true);
    #endif
    }

    #ifndef QT_NO_DRAGANDDROP
    void TorrentView::dragMoveEvent(QDragMoveEvent *event)
    {
        // Accept file actions with a '.torrent' extension.
        QUrl url(event->mimeData()->text());
        if (url.isValid() && url.scheme().toLower() == "file"
                && url.path().toLower().endsWith(".torrent"))
            event->acceptProposedAction();
    }

    void TorrentView::dropEvent(QDropEvent *event)
    {
        // Accept drops if the file has a '.torrent' extension and it
        // exists.
        QString fileName = QUrl(event->mimeData()->text()).path();
        if (QFile::exists(fileName) && fileName.toLower().endsWith(".torrent"))
            emit fileDropped(fileName);
    }
    #endif

    #include "mainwindow.moc"