TuplesAvailableMailbox.h

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#ifndef TUPLESAVAILABLEMAILBOX_H
#define TUPLESAVAILABLEMAILBOX_H

#include <set>
#include <pthread.h>

#include "common.h"

BOREALIS_NAMESPACE_BEGIN;

class TupleQueue;

typedef TupleQueue* TupleQueuePtr;

class TuplesAvailableMailbox {
public:
        TuplesAvailableMailbox();
        virtual ~TuplesAvailableMailbox();

        // Call this when the specified TupleQueue has gone from being empty to
        // being non-empty.
        //
        // Don't call this any time after you've started calling close().
        void onNonEmpty(TupleQueue * pTQ);

        // Call this method when this data structure is all done.  This will cause
        // any currently blocking call to getEvent() to unblock.
        void close();

        // If this returns true, then pTQ has been set to the address of a TupleQueue
        // that has become non-empty.  Concurrently pending non-empty reports form 
        // the same TupleQueue will be reported just once to the caller.
        //
        // If this returns false, then close() has been called.
        //
        // This method blocks until an event exists to report or close() has been
        // called.
        bool getEvent(TupleQueuePtr & pTQ);

private:
        set<TupleQueue*> _unreceivedReports;
        bool _closed;
        pthread_cond_t _cond;
        pthread_mutex_t _mtx;
};

BOREALIS_NAMESPACE_END;

#endif

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