ConnectionManager.hpp

/***************************************************************************
  tag: Peter Soetens  Thu Oct 22 11:59:08 CEST 2009  ConnectionManager.hpp

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

 ***************************************************************************
 *   This library is free software; you can redistribute it and/or         *
 *   modify it under the terms of the GNU General Public                   *
 *   License as published by the Free Software Foundation;                 *
 *   version 2 of the License.                                             *
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 *   As a special exception, you may use this file as part of a free       *
 *   software library without restriction.  Specifically, if other files   *
 *   instantiate templates or use macros or inline functions from this     *
 *   file, or you compile this file and link it with other files to        *
 *   produce an executable, this file does not by itself cause the         *
 *   resulting executable to be covered by the GNU General Public          *
 *   License.  This exception does not however invalidate any other        *
 *   reasons why the executable file might be covered by the GNU General   *
 *   Public License.                                                       *
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 *   Lesser General Public License for more details.                       *
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 *   Foundation, Inc., 59 Temple Place,                                    *
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 ***************************************************************************/


/*
 * ConnectionManager.hpp
 *
 *  Created on: Oct 9, 2009
 *      Author: kaltan
 */

#ifndef CONNECTIONMANAGER_HPP_
#define CONNECTIONMANAGER_HPP_


#include "ConnID.hpp"
#include "List.hpp"
#include "../ConnPolicy.hpp"
#include "../os/Mutex.hpp"
#include "../base/rtt-base-fwd.hpp"
#include "../base/ChannelElementBase.hpp"
#include <boost/tuple/tuple.hpp>
#include <boost/bind.hpp>
#include <boost/shared_ptr.hpp>
#include <boost/lambda/lambda.hpp>

#include <rtt/os/Mutex.hpp>
#include <rtt/os/MutexLock.hpp>
#include <list>


namespace RTT
{

    namespace internal
    {
        class RTT_API ConnectionManager
        {
        public:
            typedef boost::tuple<boost::shared_ptr<ConnID>, base::ChannelElementBase::shared_ptr, ConnPolicy> ChannelDescriptor;

            ConnectionManager(base::PortInterface* port);
            ~ConnectionManager();

            void addConnection(ConnID* port_id, base::ChannelElementBase::shared_ptr channel_input, ConnPolicy policy);

            bool removeConnection(ConnID* port_id);

            void disconnect();

            bool connected() const;

            bool disconnect(base::PortInterface* port);

            template<typename Pred>
            bool delete_if(Pred pred) {
                RTT::os::MutexLock lock(connection_lock);
                bool result = false;
                std::list<ChannelDescriptor>::iterator it = connections.begin();
                while (it != connections.end())
                {
                    if (pred(*it))
                    {
                        result = true;
                        it = connections.erase(it);
                    }
                    else ++it;
                }
                return result;
            }

            template<typename Pred>
            void select_reader_channel(Pred pred, bool copy_old_data) {
                RTT::os::MutexLock lock(connection_lock);
                std::pair<bool, ChannelDescriptor> new_channel =
                    find_if(pred, copy_old_data);
                if (new_channel.first)
                {
                    // We don't clear the current channel (to get it to NoData state), because there is a race
                    // between find_if and this line. We have to accept (in other parts of the code) that eventually,
                    // all channels return 'OldData'.
                    cur_channel = new_channel.second;
                }
            }

            template<typename Pred>
            std::pair<bool, ChannelDescriptor> find_if(Pred pred, bool copy_old_data) {
                // We only copy OldData in the initial read of the current channel.
                // if it has no new data, the search over the other channels starts,
                // but no old data is needed.
                ChannelDescriptor channel = cur_channel;
                if ( channel.get<1>() )
                    if ( pred( copy_old_data, channel ) )
                        return std::make_pair(true, channel);

                std::list<ChannelDescriptor>::iterator result;
                for (result = connections.begin(); result != connections.end(); ++result)
                    if ( pred(false, *result) == true)
                        return std::make_pair(true, *result);
                return std::make_pair(false, ChannelDescriptor());
            }

            bool isSingleConnection() const { return connections.size() == 1; }

            base::ChannelElementBase* getCurrentChannel() const {
                return cur_channel.get<1>().get();
            }

            std::list<ChannelDescriptor> getChannels() const {
                return connections;
            }

            void clear();

        protected:

            void updateCurrentChannel(bool reset_current);

            bool findMatchingPort(ConnID const* conn_id, ChannelDescriptor const& descriptor);

            bool eraseConnection(ChannelDescriptor& descriptor);

            os::Mutex connection_resize_mtx;

            base::PortInterface* mport;

            std::list< ChannelDescriptor > connections;

            ChannelDescriptor cur_channel;

            RTT::os::Mutex connection_lock;
        };

    }

}

#endif /* CONNECTIONMANAGER_HPP_ */