Run SerialLink on main thread

This is needed for Android since it needs to communicate with java apis
which require everything on the main thread. The additional thread was
not really needed since you can implement using a signal based approach
which ends up being the same thing.

src/comm/SerialLink.cc

@@ -37,9 +37,6 @@ SerialLink::SerialLink(SerialConfiguration* config)
     Q_ASSERT(config != NULL);
     _config = config;
     _config->setLink(this);
-    // We're doing it wrong - because the Qt folks got the API wrong:
-    // http://blog.qt.digia.com/blog/2010/06/17/youre-doing-it-wrong/
-    moveToThread(this);
 
     qCDebug(SerialLinkLog) << "Create SerialLink " << config->portName() << config->baud() << config->flowControl()
              << config->parity() << config->dataBits() << config->stopBits();
@@ -59,10 +56,6 @@ SerialLink::~SerialLink()
     _disconnect();
     if(_port) delete _port;
     _port = NULL;
-    // Tell the thread to exit
-    quit();
-    // Wait for it to exit
-    wait();
 }
 
 bool SerialLink::_isBootloader()
@@ -87,130 +80,11 @@ bool SerialLink::_isBootloader()
     return false;
 }
 
-/**
- * @brief Runs the thread
- *
- **/
-void SerialLink::run()
-{
-#ifndef __android__
-    // Initialize the connection
-    if (!_hardwareConnect(_type)) {
-        // Need to error out here.
-        QString err("Could not create port.");
-        if (_port) {
-            err = _port->errorString();
-        }
-        _emitLinkError("Error connecting: " + err);
-        return;
-    }
-#endif
-
-    qint64  msecs = QDateTime::currentMSecsSinceEpoch();
-    qint64  initialmsecs = QDateTime::currentMSecsSinceEpoch();
-    quint64 bytes = 0;
-    qint64  timeout = 5000;
-    int linkErrorCount = 0;
-
-    // Qt way to make clear what a while(1) loop does
-    forever {
-        {
-            QMutexLocker locker(&this->_stoppMutex);
-            if (_stopp) {
-                _stopp = false;
-                break; // exit the thread
-            }
-        }
-
-        // Write all our buffered data out the serial port.
-        if (_transmitBuffer.count() > 0) {
-            _writeMutex.lock();
-            int numWritten = _port->write(_transmitBuffer);
-            bool txSuccess = _port->flush();
-            txSuccess |= _port->waitForBytesWritten(10);
-            if (!txSuccess || (numWritten != _transmitBuffer.count())) {
-                linkErrorCount++;
-                qCDebug(SerialLinkLog) << "TX Error! written:" << txSuccess << "wrote" << numWritten << ", asked for " << _transmitBuffer.count() << "bytes";
-            }
-            else {
-
-                // Since we were successful, reset out error counter.
-                linkErrorCount = 0;
-            }
-
-            // Now that we transmit all of the data in the transmit buffer, flush it.
-            _transmitBuffer = _transmitBuffer.remove(0, numWritten);
-            _writeMutex.unlock();
-
-            // Log this written data for this timestep. If this value ends up being 0 due to
-            // write() failing, that's what we want as well.
-            QMutexLocker dataRateLocker(&dataRateMutex);
-            logDataRateToBuffer(outDataWriteAmounts, outDataWriteTimes, &outDataIndex, numWritten, QDateTime::currentMSecsSinceEpoch());
-        }
-
-        //wait n msecs for data to be ready
-        //[TODO][BB] lower to SerialLink::poll_interval?
-        _dataMutex.lock();
-        bool success = _port->waitForReadyRead(20);
-
-        if (success) {
-            QByteArray readData = _port->readAll();
-            while (_port->waitForReadyRead(10))
-                readData += _port->readAll();
-            _dataMutex.unlock();
-            if (readData.length() > 0) {
-                emit bytesReceived(this, readData);
-
-                // Log this data reception for this timestep
-                QMutexLocker dataRateLocker(&dataRateMutex);
-                logDataRateToBuffer(inDataWriteAmounts, inDataWriteTimes, &inDataIndex, readData.length(), QDateTime::currentMSecsSinceEpoch());
-
-                // Track the total amount of data read.
-                _bytesRead += readData.length();
-                linkErrorCount = 0;
-            }
-        }
-        else {
-            _dataMutex.unlock();
-            linkErrorCount++;
-        }
-
-        if (bytes != _bytesRead) { // i.e things are good and data is being read.
-            bytes = _bytesRead;
-            msecs = QDateTime::currentMSecsSinceEpoch();
-        }
-        else {
-            if (QDateTime::currentMSecsSinceEpoch() - msecs > timeout) {
-                //It's been 10 seconds since the last data came in. Reset and try again
-                msecs = QDateTime::currentMSecsSinceEpoch();
-                if (msecs - initialmsecs > 25000) {
-                    //After initial 25 seconds, timeouts are increased to 30 seconds.
-                    //This prevents temporary silences from things like calibration commands
-                    //from screwing things up. In all reality, timeouts should be enabled/disabled
-                    //for events like that on a case by case basis.
-                    //TODO ^^
-                    timeout = 30000;
-                }
-            }
-        }
-        QGC::SLEEP::msleep(SerialLink::poll_interval);
-    } // end of forever
-
-    if (_port) {
-        qCDebug(SerialLinkLog) << "Closing Port #" << __LINE__ << _port->portName();
-        _port->close();
-        delete _port;
-        _port = NULL;
-    }
-}
-
 void SerialLink::writeBytes(const char* data, qint64 size)
 {
     if(_port && _port->isOpen()) {
-        QByteArray byteArray(data, size);
-        _writeMutex.lock();
-        _transmitBuffer.append(byteArray);
-        _writeMutex.unlock();
+        _logOutputDataRate(size, QDateTime::currentMSecsSinceEpoch());
+        _port->write(data, size);
     } else {
         // Error occured
         _emitLinkError(tr("Could not send data - link %1 is disconnected!").arg(getName()));
@@ -231,10 +105,12 @@ void SerialLink::readBytes()
         _dataMutex.lock();
         qint64 numBytes = _port->bytesAvailable();
 
-        if(numBytes > 0) {
+        if (numBytes > 0) {
             /* Read as much data in buffer as possible without overflow */
             if(maxLength < numBytes) numBytes = maxLength;
 
+            _logInputDataRate(numBytes, QDateTime::currentMSecsSinceEpoch());
+            
             _port->read(data, numBytes);
             QByteArray b(data, numBytes);
             emit bytesReceived(this, b);
@@ -250,17 +126,12 @@ void SerialLink::readBytes()
  **/
 bool SerialLink::_disconnect(void)
 {
-    if (isRunning())
-    {
-        {
-            QMutexLocker locker(&_stoppMutex);
-            _stopp = true;
-        }
-        wait(); // This will terminate the thread and close the serial port
-    } else {
-        _transmitBuffer.clear(); //clear the output buffer to avoid sending garbage at next connect
-        qCDebug(SerialLinkLog) << "Already disconnected";
+    if (_port) {
+        _port->close();
+        delete _port;
+        _port = NULL;
     }
+    
 #ifdef __android__
     LinkManager::instance()->suspendConfigurationUpdates(false);
 #endif
@@ -275,14 +146,13 @@ bool SerialLink::_disconnect(void)
 bool SerialLink::_connect(void)
 {
     qCDebug(SerialLinkLog) << "CONNECT CALLED";
-    if (isRunning())
-        _disconnect();
-    {
-        QMutexLocker locker(&this->_stoppMutex);
-        _stopp = false;
-    }
+
+    _disconnect();
+    
 #ifdef __android__
     LinkManager::instance()->suspendConfigurationUpdates(true);
+#endif
+    
     // Initialize the connection
     if (!_hardwareConnect(_type)) {
         // Need to error out here.
@@ -293,8 +163,6 @@ bool SerialLink::_connect(void)
         _emitLinkError("Error connecting: " + err);
         return false;
     }
-#endif
-    start(HighPriority);
     return true;
 }
 
@@ -343,12 +211,12 @@ bool SerialLink::_hardwareConnect(QString &type)
         emit communicationUpdate(getName(),"Error opening port: " + _config->portName());
         return false; // couldn't create serial port.
     }
-    _port->moveToThread(this);
 
     // We need to catch this signal and then emit disconnected. You can't connect
     // signal to signal otherwise disonnected will have the wrong QObject::Sender
     QObject::connect(_port, SIGNAL(aboutToClose()), this, SLOT(_rerouteDisconnected()));
     QObject::connect(_port, SIGNAL(error(QSerialPort::SerialPortError)), this, SLOT(linkError(QSerialPort::SerialPortError)));
+    QObject::connect(_port, &QIODevice::readyRead, this, &SerialLink::_readBytes);
 
     //  port->setCommTimeouts(QSerialPort::CtScheme_NonBlockingRead);
 
@@ -371,6 +239,8 @@ bool SerialLink::_hardwareConnect(QString &type)
     if (!_port->isOpen() ) {
         emit communicationUpdate(getName(),"Error opening port: " + _port->errorString());
         _port->close();
+        delete _port;
+        _port = NULL;
         return false; // couldn't open serial port
     }
 
@@ -390,6 +260,18 @@ bool SerialLink::_hardwareConnect(QString &type)
     return true; // successful connection
 }
 
+void SerialLink::_readBytes(void)
+{
+    qint64 byteCount = _port->bytesAvailable();
+    if (byteCount)
+    {
+        QByteArray buffer;
+        buffer.resize(byteCount);
+        _port->read(buffer.data(), buffer.size());
+        emit bytesReceived(this, buffer);
+    }
+}
+
 void SerialLink::linkError(QSerialPort::SerialPortError error)
 {
     if (error != QSerialPort::NoError) {
@@ -493,6 +375,7 @@ void SerialLink::_rerouteDisconnected(void)
 void SerialLink::_emitLinkError(const QString& errorMsg)
 {
     QString msg("Error on link %1. %2");
+    qDebug() << errorMsg;
     emit communicationError(tr("Link Error"), msg.arg(getName()).arg(errorMsg));
 }
 

src/comm/SerialLink.h

@@ -124,10 +124,6 @@ public:
     bool    connect(void);
     bool    disconnect(void);
 
-    void run();
-
-    static const int poll_interval = SERIAL_POLL_INTERVAL; ///< Polling interval, defined in QGCConfig.h
-
 signals: //[TODO] Refactor to Linkinterface
     void updateLink(LinkInterface*);
 
@@ -154,6 +150,7 @@ protected:
 
 private slots:
     void _rerouteDisconnected(void);
+    void _readBytes(void);
 
 private:
     // Links are only created/destroyed by LinkManager so constructor/destructor is not public