MQChannelElement.hpp

/***************************************************************************
  tag: Peter Soetens  Thu Oct 22 11:59:07 CEST 2009  MQChannelElement.hpp

                        MQChannelElement.hpp -  description
                           -------------------
    begin                : Thu October 22 2009
    copyright            : (C) 2009 Peter Soetens
    email                : peter@thesourcworks.com

 ***************************************************************************
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#ifndef MQ_CHANNEL_ELEMENT_H
#define MQ_CHANNEL_ELEMENT_H

#include "MQSendRecv.hpp"
#include "../../Logger.hpp"
#include "../../base/ChannelElement.hpp"
#include "../../internal/DataSource.hpp"
#include "../../internal/DataSources.hpp"
#include <stdexcept>

namespace RTT
{
    namespace mqueue
    {
        template<typename T>
        class MQChannelElement: public base::ChannelElement<T>, public MQSendRecv
        {
            typename internal::ValueDataSource<T>::shared_ptr read_sample;
            typename internal::LateConstReferenceDataSource<T>::shared_ptr write_sample;

        public:
            MQChannelElement(base::PortInterface* port, types::TypeMarshaller const& transport,
                             const ConnPolicy& policy, bool is_sender)
                : MQSendRecv(transport)
                , read_sample(new internal::ValueDataSource<T>)
                , write_sample(new internal::LateConstReferenceDataSource<T>)

            {
                Logger::In in("MQChannelElement");
                setupStream(read_sample, port, policy, is_sender);
            }

            ~MQChannelElement() {
                cleanupStream();
            }

            virtual bool inputReady() {
                if ( mqReady(read_sample, this) ) {
                    typename base::ChannelElement<T>::shared_ptr output =
                        this->getOutput();
                    assert(output);
                    output->data_sample(read_sample->rvalue());
                    return true;
                }
                return false;
            }

            virtual bool data_sample(typename base::ChannelElement<T>::param_t sample)
            {
                // send initial data sample to the other side using a plain write.
                if (mis_sender) {
                    typename base::ChannelElement<T>::shared_ptr output =
                        this->getOutput();

                    write_sample->setPointer(&sample);
                    // update MQSendRecv buffer:
                    mqNewSample(write_sample);
                    return mqWrite(write_sample);
                }
                return false;
            }

            bool signal()
            {
                // copy messages into channel
                if (mis_sender) {
                    // this read should always succeed since signal() means
                    // 'data available in a data element'.
                    typename base::ChannelElement<T>::shared_ptr input =
                        this->getInput();
                    if( input && input->read(read_sample->set(), false) == NewData )
                        return this->write(read_sample->rvalue());
                } else {
                    typename base::ChannelElement<T>::shared_ptr output =
                        this->getOutput();
                    if (output && mqRead(read_sample))
                        return output->write(read_sample->rvalue());
                }
                return false;
            }

            FlowStatus read(typename base::ChannelElement<T>::reference_t sample, bool copy_old_data)
            {
                throw std::runtime_error("not implemented");
            }

            bool write(typename base::ChannelElement<T>::param_t sample)
            {
                write_sample->setPointer(&sample);
                return mqWrite(write_sample);
            }

        };
    }
}

#endif