RemoteProcedure.h

/*
 * Copyright (C) 2009-2014 by Dr. Marc Boris Duerner
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * 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 Library
 * General Public License.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifndef Pt_Remoting_RemoteProcedure_h
#define Pt_Remoting_RemoteProcedure_h

#include <Pt/Remoting/Api.h>
#include <Pt/Remoting/Client.h>
#include <Pt/SerializationContext.h>
#include <Pt/NonCopyable.h>
#include <Pt/Signal.h>
#include <Pt/String.h>
#include <string>

namespace Pt {

namespace Remoting {

class PT_REMOTING_API RemoteCall : private Pt::NonCopyable
{
    public:
        RemoteCall(Client& client, const String& name);

        RemoteCall(Client& client, const std::string& name);

        RemoteCall(Client& client, const char* name);

        virtual ~RemoteCall();

        Client& client()
        { return *_client; }

        const String& name() const
        { return _name; }

        bool isFailed() const
        { return _client->isFailed(); }

        void cancel();

        void setReady();

        void endCall();

    protected:
        virtual void onReady() = 0;

        virtual void onReset() = 0;

        virtual void onClear() = 0;

    private:
        Client* _client;
        String _name;
};

template <typename R>
class Result : private Pt::NonCopyable
{
    public:
        explicit Result(RemoteCall* call = 0)
        : _call(call)
        , _result(0)
        { 
            _result = new (_mem) R;
        }

        ~Result()
        {
            _result->~R();
        }

        void init(RemoteCall* call)
        { _call = call; }

        bool isFailed() const
        {
            return _call->isFailed();
        }

        R& value()
        { return *_result; }

        const R& get() const
        {
            _call->endCall();
            return *_result;
        }

        void clear()
        {
            _result->~R();
            _result = new (_mem) R;
        }

    private:
        RemoteCall* _call;
        char _mem[ sizeof(R) ];
        R* _result;
};

template <typename R>
class RemoteProcedureBase : public RemoteCall
{
    public:
        RemoteProcedureBase(Client& client, const std::string& name)
        : RemoteCall(client, name)
        , _result(0)
        , _r(0)
        { 
          _result.init(this);
        }

        ~RemoteProcedureBase()
        {
            if(_r)
                _r->~BasicComposer<R>();
        }

        Result<R>& result()
        { 
            return _result; 
        }

        const Result<R>& result() const
        {
            return _result;
        }

        Signal< const Result<R>& >& finished()
        { return _finished; }

    protected:
        void onReady()
        { _finished.send(_result); }

        BasicComposer<R>& beginResult()
        {
            if(_r)
            {
                _r->~BasicComposer<R>();
                _r = 0;
            }

            _r = new (_mem) BasicComposer<R>( &client().context() );
            _r->begin( result().value() );
            return *_r;
        }

        virtual void onReset()
        {
            if(_r)
            {
                _r->~BasicComposer<R>();
                _r = 0;
            }
        }

        virtual void onClear()
        {
            this->onReset();
            _result.clear();
        }

    private:
        Signal< const Result<R>& > _finished;
        Result<R> _result;
        char _mem[ sizeof(BasicComposer<R>) ];
        BasicComposer<R>* _r;
};


template <typename A>
class RemoteArgument : private Pt::NonCopyable
{
    public:
        RemoteArgument(SerializationContext* )
        : _decomposer(0)
        { }

        ~RemoteArgument()
        {
            if(_decomposer)
                _decomposer->~BasicDecomposer<A>();
        }

        void begin(const A& a, const char* name, SerializationContext& ctx)
        {
            if(_decomposer)
            {
                _decomposer->~BasicDecomposer<A>();
                _decomposer = 0;
            }

            _decomposer = new (_mem) BasicDecomposer<A>(&ctx);
            _decomposer->begin(a, name);
        }

        void clear(SerializationContext* )
        {
            if(_decomposer)
            {
                _decomposer->~BasicDecomposer<A>();
                _decomposer = 0;
            }
        }

        // TODO: return decomposer pointer from begin
        BasicDecomposer<A>* decomposer()
        { return reinterpret_cast<BasicDecomposer<A>*>(_mem); }

    private:
        char _mem[ sizeof(BasicDecomposer<A>) ];
        BasicDecomposer<A>* _decomposer;
};

} // namespace Remoting

} // namespace Pt

#include <Pt/Remoting/RemoteProcedure.tpp>

#endif // Pt_Remoting_RemoteProcedure_h