Qt 5.9 | Qt Serial Port | Blocking Master Example | masterthread.cpp Example File

Qt 5.9.4 Reference Documentation

# masterthread.cpp Example File

blockingmaster/masterthread.cpp

      /****************************************************************************
      **
      ** Copyright (C) 2012 Denis Shienkov <denis.shienkov@gmail.com>
      ** Contact: https://www.qt.io/licensing/
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      ** This file is part of the QtSerialPort module of the Qt Toolkit.
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      #include "masterthread.h"

      #include <QtSerialPort/QSerialPort>

      #include <QTime>

      QT_USE_NAMESPACE

      MasterThread::MasterThread(QObject *parent)
          : QThread(parent), waitTimeout(0), quit(false)
      {
      }

      MasterThread::~MasterThread()
      {
          mutex.lock();
          quit = true;
          cond.wakeOne();
          mutex.unlock();
          wait();
      }

      void MasterThread::transaction(const QString &portName, int waitTimeout, const QString &request)
      {
          QMutexLocker locker(&mutex);
          this->portName = portName;
          this->waitTimeout = waitTimeout;
          this->request = request;
          if (!isRunning())
              start();
          else
              cond.wakeOne();
      }

      void MasterThread::run()
      {
          bool currentPortNameChanged = false;

          mutex.lock();
          QString currentPortName;
          if (currentPortName != portName) {
              currentPortName = portName;
              currentPortNameChanged = true;
          }

          int currentWaitTimeout = waitTimeout;
          QString currentRequest = request;
          mutex.unlock();
          QSerialPort serial;

          if (currentPortName.isEmpty()) {
              emit error(tr("No port name specified"));
              return;
          }

          while (!quit) {
              if (currentPortNameChanged) {
                  serial.close();
                  serial.setPortName(currentPortName);

                  if (!serial.open(QIODevice::ReadWrite)) {
                      emit error(tr("Can't open %1, error code %2")
                                 .arg(portName).arg(serial.error()));
                      return;
                  }
              }
              // write request
              QByteArray requestData = currentRequest.toLocal8Bit();
              serial.write(requestData);
              if (serial.waitForBytesWritten(waitTimeout)) {
                  // read response
                  if (serial.waitForReadyRead(currentWaitTimeout)) {
                      QByteArray responseData = serial.readAll();
                      while (serial.waitForReadyRead(10))
                          responseData += serial.readAll();

                      QString response(responseData);
                      emit this->response(response);
                  } else {
                      emit timeout(tr("Wait read response timeout %1")
                                   .arg(QTime::currentTime().toString()));
                  }
              } else {
                  emit timeout(tr("Wait write request timeout %1")
                               .arg(QTime::currentTime().toString()));
              }
              mutex.lock();
              cond.wait(&mutex);
              if (currentPortName != portName) {
                  currentPortName = portName;
                  currentPortNameChanged = true;
              } else {
                  currentPortNameChanged = false;
              }
              currentWaitTimeout = waitTimeout;
              currentRequest = request;
              mutex.unlock();
          }
      }