- Qt 5.5
- Qt WebEngine Widgets
- WebEngine Tab Browser Example
- downloadmanager.cpp Example File
- Qt 5.5.1 Reference Documentation

# downloadmanager.cpp Example File

browser/downloadmanager.cpp

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    #include "downloadmanager.h"

    #include "autosaver.h"
    #include "browserapplication.h"
    #include "networkaccessmanager.h"

    #include <math.h>

    #include <QtCore/QMetaEnum>
    #include <QtCore/QSettings>

    #include <QtGui/QDesktopServices>
    #include <QtWidgets/QFileDialog>
    #include <QtWidgets/QHeaderView>
    #include <QtWidgets/QFileIconProvider>

    #include <QtCore/QDebug>

    #include <QWebEngineSettings>
    #include <QWebEngineDownloadItem>

    /*!
        DownloadWidget is a widget that is displayed in the download manager list.
        It moves the data from the QWebEngineDownloadItem into the QFile as well
        as update the information/progressbar and report errors.
     */

    DownloadWidget::DownloadWidget(QWebEngineDownloadItem *download, QWidget *parent)
        : QWidget(parent)
        , m_bytesReceived(0)
        , m_download(download)
    {
        setupUi(this);
        QPalette p = downloadInfoLabel->palette();
        p.setColor(QPalette::Text, Qt::darkGray);
        downloadInfoLabel->setPalette(p);
        progressBar->setMaximum(0);
        connect(stopButton, SIGNAL(clicked()), this, SLOT(stop()));
        connect(openButton, SIGNAL(clicked()), this, SLOT(open()));

        if (download) {
            m_file.setFile(download->path());
            m_url = download->url();
        }

        init();
    }

    void DownloadWidget::init()
    {
        if (m_download) {
            connect(m_download.data(), SIGNAL(downloadProgress(qint64,qint64)),
                    this, SLOT(downloadProgress(qint64,qint64)));
            connect(m_download.data(), SIGNAL(finished()),
                    this, SLOT(finished()));
        }

        // reset info
        downloadInfoLabel->clear();
        progressBar->setValue(0);
        getFileName();

        // start timer for the download estimation
        m_downloadTime.start();
    }

    bool DownloadWidget::getFileName(bool promptForFileName)
    {
        QSettings settings;
        settings.beginGroup(QLatin1String("downloadmanager"));
        QString defaultLocation = QStandardPaths::writableLocation(QStandardPaths::DesktopLocation);
        if (m_file.absoluteDir().exists())
            defaultLocation = m_file.absolutePath();
        QString downloadDirectory = settings.value(QLatin1String("downloadDirectory"), defaultLocation).toString();
        if (!downloadDirectory.isEmpty())
            downloadDirectory += QLatin1Char('/');

        QString defaultFileName = QFileInfo(downloadDirectory, m_file.fileName()).absoluteFilePath();
        QString fileName = defaultFileName;
        if (promptForFileName) {
            fileName = QFileDialog::getSaveFileName(this, tr("Save File"), defaultFileName);
            if (fileName.isEmpty()) {
                if (m_download)
                    m_download->cancel();
                fileNameLabel->setText(tr("Download canceled: %1").arg(QFileInfo(defaultFileName).fileName()));
                return false;
            }
        }
        m_file.setFile(fileName);

        if (m_download && m_download->state() == QWebEngineDownloadItem::DownloadRequested)
            m_download->setPath(m_file.absoluteFilePath());

        fileNameLabel->setText(m_file.fileName());
        return true;
    }

    void DownloadWidget::stop()
    {
        setUpdatesEnabled(false);
        stopButton->setEnabled(false);
        stopButton->hide();
        setUpdatesEnabled(true);
        if (m_download)
            m_download->cancel();

        emit statusChanged();
    }

    void DownloadWidget::open()
    {
        QUrl url = QUrl::fromLocalFile(m_file.absolutePath());
        QDesktopServices::openUrl(url);
    }

    void DownloadWidget::downloadProgress(qint64 bytesReceived, qint64 bytesTotal)
    {
        m_bytesReceived = bytesReceived;
        if (bytesTotal == -1) {
            progressBar->setValue(0);
            progressBar->setMaximum(0);
        } else {
            progressBar->setValue(bytesReceived);
            progressBar->setMaximum(bytesTotal);
        }
        updateInfoLabel();
    }

    void DownloadWidget::updateInfoLabel()
    {
        qint64 bytesTotal = progressBar->maximum();

        // update info label
        double speed = m_bytesReceived * 1000.0 / m_downloadTime.elapsed();
        double timeRemaining = ((double)(bytesTotal - m_bytesReceived)) / speed;
        QString timeRemainingString = tr("seconds");
        if (timeRemaining > 60) {
            timeRemaining = timeRemaining / 60;
            timeRemainingString = tr("minutes");
        }
        timeRemaining = floor(timeRemaining);

        // When downloading the eta should never be 0
        if (timeRemaining == 0)
            timeRemaining = 1;

        QString info;
        if (!downloadedSuccessfully()) {
            QString remaining;
            if (bytesTotal != 0)
                remaining = tr("- %4 %5 remaining")
                .arg(timeRemaining)
                .arg(timeRemainingString);
            info = tr("%1 of %2 (%3/sec) %4")
                .arg(dataString(m_bytesReceived))
                .arg(bytesTotal == 0 ? tr("?") : dataString(bytesTotal))
                .arg(dataString((int)speed))
                .arg(remaining);
        } else {
            if (m_bytesReceived != bytesTotal) {
                info = tr("%1 of %2 - Stopped")
                    .arg(dataString(m_bytesReceived))
                    .arg(dataString(bytesTotal));
            } else
                info = dataString(m_bytesReceived);
        }
        downloadInfoLabel->setText(info);
    }

    QString DownloadWidget::dataString(int size) const
    {
        QString unit;
        if (size < 1024) {
            unit = tr("bytes");
        } else if (size < 1024*1024) {
            size /= 1024;
            unit = tr("kB");
        } else {
            size /= 1024*1024;
            unit = tr("MB");
        }
        return QString(QLatin1String("%1 %2")).arg(size).arg(unit);
    }

    bool DownloadWidget::downloading() const
    {
        return (progressBar->isVisible());
    }

    bool DownloadWidget::downloadedSuccessfully() const
    {
        bool completed = m_download
                && m_download->isFinished()
                && m_download->state() == QWebEngineDownloadItem::DownloadCompleted;
        return completed || !stopButton->isVisible();
    }

    void DownloadWidget::finished()
    {
        if (m_download) {
            QWebEngineDownloadItem::DownloadState state = m_download->state();
            QString message;
            bool interrupted = false;

            switch (state) {
            case QWebEngineDownloadItem::DownloadRequested: // Fall-through.
            case QWebEngineDownloadItem::DownloadInProgress:
                Q_UNREACHABLE();
                break;
            case QWebEngineDownloadItem::DownloadCompleted:
                break;
            case QWebEngineDownloadItem::DownloadCancelled:
                message = QStringLiteral("Download cancelled");
                interrupted = true;
                break;
            case QWebEngineDownloadItem::DownloadInterrupted:
                message = QStringLiteral("Download interrupted");
                interrupted = true;
                break;
            }

            if (interrupted) {
                downloadInfoLabel->setText(message);
                return;
            }
        }

        progressBar->hide();
        stopButton->setEnabled(false);
        stopButton->hide();
        updateInfoLabel();
        emit statusChanged();
    }

    /*!
        DownloadManager is a Dialog that contains a list of DownloadWidgets

        It is a basic download manager.  It only downloads the file, doesn't do BitTorrent,
        extract zipped files or anything fancy.
      */
    DownloadManager::DownloadManager(QWidget *parent)
        : QDialog(parent)
        , m_autoSaver(new AutoSaver(this))
        , m_iconProvider(0)
        , m_removePolicy(Never)
    {
        setupUi(this);
        downloadsView->setShowGrid(false);
        downloadsView->verticalHeader()->hide();
        downloadsView->horizontalHeader()->hide();
        downloadsView->setAlternatingRowColors(true);
        downloadsView->horizontalHeader()->setStretchLastSection(true);
        m_model = new DownloadModel(this);
        downloadsView->setModel(m_model);
        connect(cleanupButton, SIGNAL(clicked()), this, SLOT(cleanup()));
        load();
    }

    DownloadManager::~DownloadManager()
    {
        m_autoSaver->changeOccurred();
        m_autoSaver->saveIfNeccessary();
        if (m_iconProvider)
            delete m_iconProvider;
    }

    int DownloadManager::activeDownloads() const
    {
        int count = 0;
        for (int i = 0; i < m_downloads.count(); ++i) {
            if (m_downloads.at(i)->stopButton->isEnabled())
                ++count;
        }
        return count;
    }

    void DownloadManager::download(QWebEngineDownloadItem *download)
    {
        DownloadWidget *widget = new DownloadWidget(download, this);
        addItem(widget);
    }

    void DownloadManager::addItem(DownloadWidget *widget)
    {
        connect(widget, SIGNAL(statusChanged()), this, SLOT(updateRow()));
        int row = m_downloads.count();
        m_model->beginInsertRows(QModelIndex(), row, row);
        m_downloads.append(widget);
        m_model->endInsertRows();
        updateItemCount();
        if (row == 0)
            show();
        downloadsView->setIndexWidget(m_model->index(row, 0), widget);
        QIcon icon = style()->standardIcon(QStyle::SP_FileIcon);
        widget->fileIcon->setPixmap(icon.pixmap(48, 48));
        downloadsView->setRowHeight(row, widget->sizeHint().height());
    }

    void DownloadManager::updateRow()
    {
        DownloadWidget *widget = qobject_cast<DownloadWidget*>(sender());
        int row = m_downloads.indexOf(widget);
        if (-1 == row)
            return;
        if (!m_iconProvider)
            m_iconProvider = new QFileIconProvider();
        QIcon icon = m_iconProvider->icon(widget->m_file);
        if (icon.isNull())
            icon = style()->standardIcon(QStyle::SP_FileIcon);
        widget->fileIcon->setPixmap(icon.pixmap(48, 48));
        downloadsView->setRowHeight(row, widget->minimumSizeHint().height());

        bool remove = false;
        if (!widget->downloading()
            && BrowserApplication::instance()->privateBrowsing())
            remove = true;

        if (widget->downloadedSuccessfully()
            && removePolicy() == DownloadManager::SuccessFullDownload) {
            remove = true;
        }
        if (remove)
            m_model->removeRow(row);

        cleanupButton->setEnabled(m_downloads.count() - activeDownloads() > 0);
    }

    DownloadManager::RemovePolicy DownloadManager::removePolicy() const
    {
        return m_removePolicy;
    }

    void DownloadManager::setRemovePolicy(RemovePolicy policy)
    {
        if (policy == m_removePolicy)
            return;
        m_removePolicy = policy;
        m_autoSaver->changeOccurred();
    }

    void DownloadManager::save() const
    {
        QSettings settings;
        settings.beginGroup(QLatin1String("downloadmanager"));
        QMetaEnum removePolicyEnum = staticMetaObject.enumerator(staticMetaObject.indexOfEnumerator("RemovePolicy"));
        settings.setValue(QLatin1String("removeDownloadsPolicy"), QLatin1String(removePolicyEnum.valueToKey(m_removePolicy)));
        settings.setValue(QLatin1String("size"), size());
        if (m_removePolicy == Exit)
            return;

        for (int i = 0; i < m_downloads.count(); ++i) {
            QString key = QString(QLatin1String("download_%1_")).arg(i);
            settings.setValue(key + QLatin1String("url"), m_downloads[i]->m_url);
            settings.setValue(key + QLatin1String("location"), m_downloads[i]->m_file.filePath());
            settings.setValue(key + QLatin1String("done"), m_downloads[i]->downloadedSuccessfully());
        }
        int i = m_downloads.count();
        QString key = QString(QLatin1String("download_%1_")).arg(i);
        while (settings.contains(key + QLatin1String("url"))) {
            settings.remove(key + QLatin1String("url"));
            settings.remove(key + QLatin1String("location"));
            settings.remove(key + QLatin1String("done"));
            key = QString(QLatin1String("download_%1_")).arg(++i);
        }
    }

    void DownloadManager::load()
    {
        QSettings settings;
        settings.beginGroup(QLatin1String("downloadmanager"));
        QSize size = settings.value(QLatin1String("size")).toSize();
        if (size.isValid())
            resize(size);
        QByteArray value = settings.value(QLatin1String("removeDownloadsPolicy"), QLatin1String("Never")).toByteArray();
        QMetaEnum removePolicyEnum = staticMetaObject.enumerator(staticMetaObject.indexOfEnumerator("RemovePolicy"));
        m_removePolicy = removePolicyEnum.keyToValue(value) == -1 ?
                            Never :
                            static_cast<RemovePolicy>(removePolicyEnum.keyToValue(value));

        int i = 0;
        QString key = QString(QLatin1String("download_%1_")).arg(i);
        while (settings.contains(key + QLatin1String("url"))) {
            QUrl url = settings.value(key + QLatin1String("url")).toUrl();
            QString fileName = settings.value(key + QLatin1String("location")).toString();
            bool done = settings.value(key + QLatin1String("done"), true).toBool();
            if (done && !url.isEmpty() && !fileName.isEmpty()) {
                DownloadWidget *widget = new DownloadWidget(0, this);
                widget->m_file.setFile(fileName);
                widget->fileNameLabel->setText(widget->m_file.fileName());
                widget->m_url = url;
                widget->stopButton->setVisible(false);
                widget->stopButton->setEnabled(false);
                widget->progressBar->hide();
                addItem(widget);
            }
            key = QString(QLatin1String("download_%1_")).arg(++i);
        }
        cleanupButton->setEnabled(m_downloads.count() - activeDownloads() > 0);
    }

    void DownloadManager::cleanup()
    {
        if (m_downloads.isEmpty())
            return;
        m_model->removeRows(0, m_downloads.count());
        updateItemCount();
        if (m_downloads.isEmpty() && m_iconProvider) {
            delete m_iconProvider;
            m_iconProvider = 0;
        }
        m_autoSaver->changeOccurred();
    }

    void DownloadManager::updateItemCount()
    {
        int count = m_downloads.count();
        itemCount->setText(count == 1 ? tr("1 Download") : tr("%1 Downloads").arg(count));
    }

    DownloadModel::DownloadModel(DownloadManager *downloadManager, QObject *parent)
        : QAbstractListModel(parent)
        , m_downloadManager(downloadManager)
    {
    }

    QVariant DownloadModel::data(const QModelIndex &index, int role) const
    {
        if (index.row() < 0 || index.row() >= rowCount(index.parent()))
            return QVariant();
        if (role == Qt::ToolTipRole)
            if (!m_downloadManager->m_downloads.at(index.row())->downloadedSuccessfully())
                return m_downloadManager->m_downloads.at(index.row())->downloadInfoLabel->text();
        return QVariant();
    }

    int DownloadModel::rowCount(const QModelIndex &parent) const
    {
        return (parent.isValid()) ? 0 : m_downloadManager->m_downloads.count();
    }

    bool DownloadModel::removeRows(int row, int count, const QModelIndex &parent)
    {
        if (parent.isValid())
            return false;

        int lastRow = row + count - 1;
        for (int i = lastRow; i >= row; --i) {
            if (m_downloadManager->m_downloads.at(i)->downloadedSuccessfully()) {
                beginRemoveRows(parent, i, i);
                m_downloadManager->m_downloads.takeAt(i)->deleteLater();
                endRemoveRows();
            }
        }
        m_downloadManager->m_autoSaver->changeOccurred();
        return true;
    }