Blocking Slave Example

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 ** Copyright (C) 2012 Denis Shienkov <denis.shienkov@gmail.com>
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 #include "slavethread.h"

 #include <QSerialPort>
 #include <QTime>

 SlaveThread::SlaveThread(QObject *parent) :
     QThread(parent)
 {
 }

 SlaveThread::~SlaveThread()
 {
     m_mutex.lock();
     m_quit = true;
     m_mutex.unlock();
     wait();
 }

 void SlaveThread::startSlave(const QString &portName, int waitTimeout, const QString &response)
 {
     const QMutexLocker locker(&m_mutex);
     m_portName = portName;
     m_waitTimeout = waitTimeout;
     m_response = response;
     if (!isRunning())
         start();
 }

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

     m_mutex.lock();
     QString currentPortName;
     if (currentPortName != m_portName) {
         currentPortName = m_portName;
         currentPortNameChanged = true;
     }

     int currentWaitTimeout = m_waitTimeout;
     QString currentRespone = m_response;
     m_mutex.unlock();
     QSerialPort serial;

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

             if (!serial.open(QIODevice::ReadWrite)) {
                 emit error(tr("Can't open %1, error code %2")
                            .arg(m_portName).arg(serial.error()));
                 return;
             }
         }

         if (serial.waitForReadyRead(currentWaitTimeout)) {
             // read request
             QByteArray requestData = serial.readAll();
             while (serial.waitForReadyRead(10))
                 requestData += serial.readAll();
             // write response
             const QByteArray responseData = currentRespone.toUtf8();
             serial.write(responseData);
             if (serial.waitForBytesWritten(m_waitTimeout)) {
                 const QString request = QString::fromUtf8(requestData);
                 emit this->request(request);
             } else {
                 emit timeout(tr("Wait write response timeout %1")
                              .arg(QTime::currentTime().toString()));
             }
         } else {
             emit timeout(tr("Wait read request timeout %1")
                          .arg(QTime::currentTime().toString()));
         }
         m_mutex.lock();
         if (currentPortName != m_portName) {
             currentPortName = m_portName;
             currentPortNameChanged = true;
         } else {
             currentPortNameChanged = false;
         }
         currentWaitTimeout = m_waitTimeout;
         currentRespone = m_response;
         m_mutex.unlock();
     }
 }