downloadmanager.cpp Example File

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  #include "downloadmanager.h"

  #include "autosaver.h"
  #include "browserapplication.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.absoluteFilePath());
      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;
  }