soa/service/async_event_source.h

/* async_event_source.h                                            -*- C++ -*-
   Jeremy Barnes, 9 November 2012
   Copyright (c) 2012 Datacratic Inc.  All rights reserved.

   Source of asynchronous events; a bit like a reactor.
*/

#ifndef __service__async_event_source_h__
#define __service__async_event_source_h__


#include <boost/thread/thread.hpp>
#include <functional>
#include "jml/arch/exception.h"
#include <thread>

namespace Datacratic {

struct MessageLoop;

/*****************************************************************************/
/* ASYNC EVENT SOURCE                                                        */
/*****************************************************************************/

struct AsyncEventSource {

    AsyncEventSource()
        : needsPoll(false), debug_(false), parent_(0)
    {
    }

    virtual ~AsyncEventSource()
    {
        disconnect();
    }

    virtual int selectFd() const
    {
        return -1;
    }

    virtual bool poll() const
    {
        return false;
    }

    virtual bool processOne() = 0;

    virtual bool singleThreaded() const
    {
        return true;
    }

    virtual void debug(bool debugOn)
    {
        debug_ = debugOn;
    }

    virtual void connected(MessageLoop * parent)
    {
        if (parent_)
            throw ML::Exception("attempt to connect AsyncEventSource "
                                "to two parents");
        parent_ = parent;
    }

    void disconnect();

    bool needsPoll;

    bool debug_;

    MessageLoop * parent_;
};


/*****************************************************************************/
/* MULTIPLE EVENT SOURCE                                                     */
/*****************************************************************************/

// ...

/*****************************************************************************/
/* PERIODIC EVENT SOURCE                                                     */
/*****************************************************************************/

struct PeriodicEventSource : public AsyncEventSource {
    PeriodicEventSource();

    PeriodicEventSource(double timePeriodSeconds,
                        std::function<void (uint64_t)> onTimeout,
                        bool singleThreaded = true);

    ~PeriodicEventSource();

    void init(double timePeriodSeconds,
              std::function<void (uint64_t)> onTimeout,
              bool singleThreaded = true);

    virtual int selectFd() const;

    virtual bool processOne();

    virtual bool singleThreaded() const
    {
        return singleThreaded_;
    }

private:    
    int timerFd;
    double timePeriodSeconds;
    std::function<void (uint64_t)> onTimeout;
    bool singleThreaded_;
};


#if 0
/*****************************************************************************/
/* WAKEUP EVENT SOURCE                                                       */
/*****************************************************************************/

struct WakeupEventSource : public AsyncEventSource {
    WakeupEventSource();

    virtual int selectFd() const;

    virtual bool processOne();

private:    
    ML::Wakeup_Fd wakeup;
};
#endif

} // namespace Datacratic


#endif /* __service__async_event_source_h__ */