CAN Bus example

 /****************************************************************************
 **
 ** Copyright (C) 2017 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the examples of the QtSerialBus module.
 **
 ** $QT_BEGIN_LICENSE:BSD$
 ** Commercial License Usage
 ** Licensees holding valid commercial Qt licenses may use this file in
 ** accordance with the commercial license agreement provided with the
 ** Software or, alternatively, in accordance with the terms contained in
 ** a written agreement between you and The Qt Company. For licensing terms
 ** and conditions see https://www.qt.io/terms-conditions. For further
 ** information use the contact form at https://www.qt.io/contact-us.
 **
 ** BSD License Usage
 ** Alternatively, 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 The Qt Company Ltd 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,
 ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #include "mainwindow.h"
 #include "ui_mainwindow.h"
 #include "connectdialog.h"

 #include <QCanBus>
 #include <QCanBusFrame>
 #include <QCloseEvent>
 #include <QDesktopServices>
 #include <QTimer>

 MainWindow::MainWindow(QWidget *parent) :
     QMainWindow(parent),
     m_ui(new Ui::MainWindow)
 {
     m_ui->setupUi(this);

     m_connectDialog = new ConnectDialog;

     m_status = new QLabel;
     m_ui->statusBar->addPermanentWidget(m_status);

     m_written = new QLabel;
     m_ui->statusBar->addWidget(m_written);

     initActionsConnections();
     QTimer::singleShot(50, m_connectDialog, &ConnectDialog::show);
 }

 MainWindow::~MainWindow()
 {
     delete m_canDevice;

     delete m_connectDialog;
     delete m_ui;
 }

 void MainWindow::initActionsConnections()
 {
     m_ui->actionDisconnect->setEnabled(false);
     m_ui->sendFrameBox->setEnabled(false);

     connect(m_ui->sendFrameBox, &SendFrameBox::sendFrame, this, &MainWindow::sendFrame);
     connect(m_ui->actionConnect, &QAction::triggered, m_connectDialog, &ConnectDialog::show);
     connect(m_connectDialog, &QDialog::accepted, this, &MainWindow::connectDevice);
     connect(m_ui->actionDisconnect, &QAction::triggered, this, &MainWindow::disconnectDevice);
     connect(m_ui->actionQuit, &QAction::triggered, this, &QWidget::close);
     connect(m_ui->actionAboutQt, &QAction::triggered, qApp, &QApplication::aboutQt);
     connect(m_ui->actionClearLog, &QAction::triggered, m_ui->receivedMessagesEdit, &QTextEdit::clear);
     connect(m_ui->actionPluginDocumentation, &QAction::triggered, this, []() {
         QDesktopServices::openUrl(QUrl("http://doc.qt.io/qt-5/qtcanbus-backends.html#can-bus-plugins"));
     });
 }

 void MainWindow::processErrors(QCanBusDevice::CanBusError error) const
 {
     switch (error) {
     case QCanBusDevice::ReadError:
     case QCanBusDevice::WriteError:
     case QCanBusDevice::ConnectionError:
     case QCanBusDevice::ConfigurationError:
     case QCanBusDevice::UnknownError:
         m_status->setText(m_canDevice->errorString());
         break;
     default:
         break;
     }
 }

 void MainWindow::connectDevice()
 {
     const ConnectDialog::Settings p = m_connectDialog->settings();

     QString errorString;
     m_canDevice = QCanBus::instance()->createDevice(p.pluginName, p.deviceInterfaceName,
                                                     &errorString);
     if (!m_canDevice) {
         m_status->setText(tr("Error creating device '%1', reason: '%2'")
                           .arg(p.pluginName).arg(errorString));
         return;
     }

     m_numberFramesWritten = 0;

     connect(m_canDevice, &QCanBusDevice::errorOccurred, this, &MainWindow::processErrors);
     connect(m_canDevice, &QCanBusDevice::framesReceived, this, &MainWindow::processReceivedFrames);
     connect(m_canDevice, &QCanBusDevice::framesWritten, this, &MainWindow::processFramesWritten);

     if (p.useConfigurationEnabled) {
         for (const ConnectDialog::ConfigurationItem &item : p.configurations)
             m_canDevice->setConfigurationParameter(item.first, item.second);
     }

     if (!m_canDevice->connectDevice()) {
         m_status->setText(tr("Connection error: %1").arg(m_canDevice->errorString()));

         delete m_canDevice;
         m_canDevice = nullptr;
     } else {
         m_ui->actionConnect->setEnabled(false);
         m_ui->actionDisconnect->setEnabled(true);

         m_ui->sendFrameBox->setEnabled(true);

         const QVariant bitRate = m_canDevice->configurationParameter(QCanBusDevice::BitRateKey);
         if (bitRate.isValid()) {
             const bool isCanFd =
                     m_canDevice->configurationParameter(QCanBusDevice::CanFdKey).toBool();
             const QVariant dataBitRate =
                     m_canDevice->configurationParameter(QCanBusDevice::DataBitRateKey);
             if (isCanFd && dataBitRate.isValid()) {
                 m_status->setText(tr("Plugin: %1, connected to %2 at %3 / %4 kBit/s")
                                   .arg(p.pluginName).arg(p.deviceInterfaceName)
                                   .arg(bitRate.toInt() / 1000).arg(dataBitRate.toInt() / 1000));
             } else {
                 m_status->setText(tr("Plugin: %1, connected to %2 at %3 kBit/s")
                                   .arg(p.pluginName).arg(p.deviceInterfaceName)
                                   .arg(bitRate.toInt() / 1000));
             }
         } else {
             m_status->setText(tr("Plugin: %1, connected to %2")
                     .arg(p.pluginName).arg(p.deviceInterfaceName));
         }
     }
 }

 void MainWindow::disconnectDevice()
 {
     if (!m_canDevice)
         return;

     m_canDevice->disconnectDevice();
     delete m_canDevice;
     m_canDevice = nullptr;

     m_ui->actionConnect->setEnabled(true);
     m_ui->actionDisconnect->setEnabled(false);

     m_ui->sendFrameBox->setEnabled(false);

     m_status->setText(tr("Disconnected"));
 }

 void MainWindow::processFramesWritten(qint64 count)
 {
     m_numberFramesWritten += count;
     m_written->setText(tr("%1 frames written").arg(m_numberFramesWritten));
 }

 void MainWindow::closeEvent(QCloseEvent *event)
 {
     m_connectDialog->close();
     event->accept();
 }

 static QString frameFlags(const QCanBusFrame &frame)
 {
     QString result = QLatin1String(" --- ");

     if (frame.hasBitrateSwitch())
         result[1] = QLatin1Char('B');
     if (frame.hasErrorStateIndicator())
         result[2] = QLatin1Char('E');
     if (frame.hasLocalEcho())
         result[3] = QLatin1Char('L');

     return result;
 }

 void MainWindow::processReceivedFrames()
 {
     if (!m_canDevice)
         return;

     while (m_canDevice->framesAvailable()) {
         const QCanBusFrame frame = m_canDevice->readFrame();

         QString view;
         if (frame.frameType() == QCanBusFrame::ErrorFrame)
             view = m_canDevice->interpretErrorFrame(frame);
         else
             view = frame.toString();

         const QString time = QString::fromLatin1("%1.%2  ")
                 .arg(frame.timeStamp().seconds(), 10, 10, QLatin1Char(' '))
                 .arg(frame.timeStamp().microSeconds() / 100, 4, 10, QLatin1Char('0'));

         const QString flags = frameFlags(frame);

         m_ui->receivedMessagesEdit->append(time + flags + view);
     }
 }

 void MainWindow::sendFrame(const QCanBusFrame &frame) const
 {
     if (!m_canDevice)
         return;

     m_canDevice->writeFrame(frame);
 }