Orocos Real-Time Toolkit  2.6.0
MQChannelElement.hpp
00001 /***************************************************************************
00002   tag: Peter Soetens  Thu Oct 22 11:59:07 CEST 2009  MQChannelElement.hpp
00003 
00004                         MQChannelElement.hpp -  description
00005                            -------------------
00006     begin                : Thu October 22 2009
00007     copyright            : (C) 2009 Peter Soetens
00008     email                : peter@thesourcworks.com
00009 
00010  ***************************************************************************
00011  *   This library is free software; you can redistribute it and/or         *
00012  *   modify it under the terms of the GNU General Public                   *
00013  *   License as published by the Free Software Foundation;                 *
00014  *   version 2 of the License.                                             *
00015  *                                                                         *
00016  *   As a special exception, you may use this file as part of a free       *
00017  *   software library without restriction.  Specifically, if other files   *
00018  *   instantiate templates or use macros or inline functions from this     *
00019  *   file, or you compile this file and link it with other files to        *
00020  *   produce an executable, this file does not by itself cause the         *
00021  *   resulting executable to be covered by the GNU General Public          *
00022  *   License.  This exception does not however invalidate any other        *
00023  *   reasons why the executable file might be covered by the GNU General   *
00024  *   Public License.                                                       *
00025  *                                                                         *
00026  *   This library is distributed in the hope that it will be useful,       *
00027  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
00028  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU     *
00029  *   Lesser General Public License for more details.                       *
00030  *                                                                         *
00031  *   You should have received a copy of the GNU General Public             *
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00033  *   Foundation, Inc., 59 Temple Place,                                    *
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00035  *                                                                         *
00036  ***************************************************************************/
00037 
00038 
00039 #ifndef MQ_CHANNEL_ELEMENT_H
00040 #define MQ_CHANNEL_ELEMENT_H
00041 
00042 #include "MQSendRecv.hpp"
00043 #include "../../Logger.hpp"
00044 #include "../../base/ChannelElement.hpp"
00045 #include "../../internal/DataSource.hpp"
00046 #include "../../internal/DataSources.hpp"
00047 #include <stdexcept>
00048 
00049 namespace RTT
00050 {
00051     namespace mqueue
00052     {
00061         template<typename T>
00062         class MQChannelElement: public base::ChannelElement<T>, public MQSendRecv
00063         {
00065             typename internal::ValueDataSource<T>::shared_ptr read_sample;
00067             typename internal::LateConstReferenceDataSource<T>::shared_ptr write_sample;
00068 
00069         public:
00074             MQChannelElement(base::PortInterface* port, types::TypeMarshaller const& transport,
00075                              const ConnPolicy& policy, bool is_sender)
00076                 : MQSendRecv(transport)
00077                 , read_sample(new internal::ValueDataSource<T>)
00078                 , write_sample(new internal::LateConstReferenceDataSource<T>)
00079 
00080             {
00081                 Logger::In in("MQChannelElement");
00082                 setupStream(read_sample, port, policy, is_sender);
00083             }
00084 
00085             ~MQChannelElement() {
00086                 cleanupStream();
00087             }
00088 
00089             virtual bool inputReady() {
00090                 if ( mqReady(read_sample, this) ) {
00091                     typename base::ChannelElement<T>::shared_ptr output =
00092                         this->getOutput();
00093                     assert(output);
00094                     output->data_sample(read_sample->rvalue());
00095                     return true;
00096                 }
00097                 return false;
00098             }
00099 
00100             virtual bool data_sample(typename base::ChannelElement<T>::param_t sample)
00101             {
00102                 // send initial data sample to the other side using a plain write.
00103                 if (mis_sender) {
00104                     typename base::ChannelElement<T>::shared_ptr output =
00105                         this->getOutput();
00106 
00107                     write_sample->setPointer(&sample);
00108                     // update MQSendRecv buffer:
00109                     mqNewSample(write_sample);
00110                     return mqWrite(write_sample);
00111                 }
00112                 return false;
00113             }
00114 
00132             bool signal()
00133             {
00134                 // copy messages into channel
00135                 if (mis_sender) {
00136                     // this read should always succeed since signal() means
00137                     // 'data available in a data element'.
00138                     typename base::ChannelElement<T>::shared_ptr input =
00139                         this->getInput();
00140                     if( input && input->read(read_sample->set(), false) == NewData )
00141                         return this->write(read_sample->rvalue());
00142                 } else {
00143                     typename base::ChannelElement<T>::shared_ptr output =
00144                         this->getOutput();
00145                     if (output && mqRead(read_sample))
00146                         return output->write(read_sample->rvalue());
00147                 }
00148                 return false;
00149             }
00150 
00156             FlowStatus read(typename base::ChannelElement<T>::reference_t sample, bool copy_old_data)
00157             {
00158                 throw std::runtime_error("not implemented");
00159             }
00160 
00166             bool write(typename base::ChannelElement<T>::param_t sample)
00167             {
00168                 write_sample->setPointer(&sample);
00169                 return mqWrite(write_sample);
00170             }
00171 
00172         };
00173     }
00174 }
00175 
00176 #endif
00177