source: vscpl/src/hu/varadiistvan/scpl/io/_posix/WaitableEvent.h

// Copyright (c) 2013 by István Váradi

// This file is part of VSCPL, a simple cross-platform utility library

// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:

// 1. Redistributions of source code must retain the above copyright notice, this
//    list of conditions and the following disclaimer.
// 2. Redistributions in binary form must reproduce the above copyright notice,
//    this list of conditions and the following disclaimer in the documentation
//    and/or other materials provided with the distribution.

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
// ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// The views and conclusions contained in the software and documentation are those
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#ifndef HU_VARADIISTVAN_SCPL_IO_POSIX_WAITABLEEVENT_H
#define HU_VARADIISTVAN_SCPL_IO_POSIX_WAITABLEEVENT_H
//------------------------------------------------------------------------------

#include "Waitable.h"

#include "../Failable.h"

//------------------------------------------------------------------------------

namespace hu { namespace varadiistvan { namespace scpl { namespace io {

//------------------------------------------------------------------------------

/**
 * An event on which one can wait with a waiter.
 */
class WaitableEvent : public Waitable
{
private:
    /**
     * Indicate if the event is fired.
     */
    volatile bool fired;

public:
    /**
     * Construct the event.
     */
    WaitableEvent(Waiter* waiter = 0);

    /**
     * Destroy the event.
     */
    virtual ~WaitableEvent();

    /**
     * Fire the event.
     */
    void fire();

    /**
     * Check if the event is fired or not. If so, the fired status
     * will be cleared.
     */
    bool check();

protected:
    /**
     * Check if the event is fired or not.
     */
    virtual bool isReady();

    /**
     * Handle the given events.
     */
    virtual void handleEvents(short events);

private:
    /**
     * Perform the real check. If we already know that we are fired,
     * just return true. Otherwise try to read from the event fd.
     */
    bool doCheck(bool fromHandleEvents = false);
};


//------------------------------------------------------------------------------

} /* namespace hu::varadiistvan::scpl::io */ } /* namespace hu::varadiistvan::scpl */ } /* namespace hu::varadiistvan */ } /* namespace hu */

//------------------------------------------------------------------------------
#endif // HU_VARADIISTVAN_SCPL_IO_POSIX_WAITABLEEVENT_H

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