gpsdmasterdevice.cpp

/*
  The MIT License (MIT)

  Copyright (c) 2016 Jörg Mechnich <joerg.mechnich@gmail.com>

  Permission is hereby granted, free of charge, to any person obtaining
  a copy of this software and associated documentation files (the
  "Software"), to deal in the Software without restriction, including
  without limitation the rights to use, copy, modify, merge, publish,
  distribute, sublicense, and/or sell copies of the Software, and to
  permit persons to whom the Software is furnished to do so, subject to
  the following conditions:
  
  The above copyright notice and this permission notice shall be
  included in all copies or substantial portions of the Software.
  
  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

#include "gpsdmasterdevice.h"

#include <QTcpSocket>
#include <QBuffer>

GpsdMasterDevice* GpsdMasterDevice::_instance = 0;

GpsdMasterDevice* GpsdMasterDevice::instance()
{
  if(!_instance)
      _instance = new GpsdMasterDevice;
  return _instance;
}

GpsdMasterDevice::GpsdMasterDevice()
        : _socket( new QTcpSocket(this))
        , _hostname("localhost")
        , _port(2947)
        , _gpsdStarted(false)
        , _timeout(1000)
{
  connect(_socket, SIGNAL( readyRead()), this, SLOT( readFromSocketAndCopy()));
  QByteArray hostname = qgetenv("GPSD_HOST");
  if( !hostname.isEmpty())
      _hostname = hostname;
  QByteArray port = qgetenv("GPSD_PORT");
  if( !port.isEmpty())
  {
    bool ok = false;
    uint tmp = port.toUInt(&ok);
    if(ok)
        _port = tmp;
  }
}

void GpsdMasterDevice::readFromSocketAndCopy()
{
  bool gotNewData = false;
  QByteArray buf;
  SlaveListT::iterator it;
  for( it=_slaves.begin(); it!=_slaves.end(); ++it)
  {
    if(it->second)
        it->first->seek(0);
  }
  while(_socket->canReadLine())
  {
    gotNewData = true;
    buf = _socket->readLine();
    for( it=_slaves.begin(); it!=_slaves.end(); ++it)
    {
      if(it->second)
          it->first->write(buf);
    }
  }
  if( gotNewData)
  {
    for( it=_slaves.begin(); it!=_slaves.end(); ++it)
    {
      if(it->second)
          it->first->seek(0);
    }
  }
}

bool GpsdMasterDevice::gpsdConnect()
{
  if( _socket->isOpen())
  {
#ifndef QT_NO_DEBUG
    qInfo() << "Already connected to gpsd";
#endif
    return true;
  }
  _socket->connectToHost(_hostname, _port);
  if( !_socket->waitForConnected(_timeout))
  {
    _socket->close();
    qCritical() << "Could not open connection to gpsd";
    return false;
  }
  
#ifndef QT_NO_DEBUG
  qInfo() << "Connected to gpsd";
#endif
  return true;
}

void GpsdMasterDevice::gpsdDisconnect()
{
  if( !_socket->isOpen())
      return;
#ifndef QT_NO_DEBUG
  qInfo() << "Disconnecting from gpsd";
#endif
  _socket->close();
}

bool GpsdMasterDevice::gpsdStart()
{
  if(!_socket->isOpen())
      return false;
  
  if(!_gpsdStarted)
  {
#ifndef QT_NO_DEBUG
    qInfo() << "Starting gpsd";
#endif
    _socket->write("?WATCH={\"enable\":true, \"nmea\":true}\n");
    _gpsdStarted = true;
  }
  return true;
}

bool GpsdMasterDevice::gpsdStop()
{
  if(!_socket->isOpen())
      return false;
  
  if(_gpsdStarted)
  {
#ifndef QT_NO_DEBUG
    qInfo() << "Stopping gpsd";
#endif
    _socket->write("?WATCH={\"enable\": false}\n");
    _gpsdStarted = false;
  }
  return true;
}
 
QIODevice* GpsdMasterDevice::createSlave()
{
  if(!_slaves.size() && !gpsdConnect())
      return 0;
  QBuffer* slave = new QBuffer(this);
  slave->open(QIODevice::ReadWrite);
  _slaves.append(qMakePair(slave,false));
#ifndef QT_NO_DEBUG
  qInfo() << "Created slave" << slave;
#endif
  return slave;
}

void GpsdMasterDevice::destroySlave(QIODevice* slave)
{
  SlaveListT::iterator it = _slaves.begin();
  for(; it!=_slaves.end(); ++it)
  {
    if(it->first == slave)
    {
      _slaves.erase(it);
#ifndef QT_NO_DEBUG
      qInfo() << "Destroyed slave" << slave;
#endif
      delete slave;
      break;
    }
  }
  if(!_slaves.size())
  {
    gpsdStop();
    gpsdDisconnect();
  }
}

void GpsdMasterDevice::pauseSlave(QIODevice* slave)
{
  bool allPaused = true;
  SlaveListT::iterator it = _slaves.begin();
  for(; it!=_slaves.end(); ++it)
  {
    if(it->first == slave)
    {
#ifndef QT_NO_DEBUG
      qInfo() << "Pausing slave" << slave;
#endif
      it->second = false;
    }
    if(it->second)
        allPaused = false;
  }
  if(allPaused)
      gpsdStop();
}

void GpsdMasterDevice::unpauseSlave(QIODevice* slave)
{
  SlaveListT::iterator it = _slaves.begin();
  for(; it!=_slaves.end(); ++it)
  {
    if(it->first == slave)
    {
#ifndef QT_NO_DEBUG
      qInfo() << "Unpausing slave" << slave;
#endif
      it->second = true;
      gpsdStart();
      break;
    }
  }
}