source: xplcommon/src/xplcommon/posix/Waitable.h@ 3:e4ca2e057cec

// Copyright (c) 2013 by István Váradi

// This file is part of libxplcommon, a common utility library for
// development related to X-Plane

// 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
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// (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
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// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// The views and conclusions contained in the software and documentation are those
// of the authors and should not be interpreted as representing official policies,
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#ifndef XPLCOMMON_POSIX_WAITABLE_H
#define XPLCOMMON_POSIX_WAITABLE_H
//------------------------------------------------------------------------------

namespace xplcommon { namespace posix {

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

class Waiter;

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

/**
 * Base class of objects for which one can wait in a Waiter.
 *
 * It is basically a file descriptor.
 */
class Waitable
{
protected:
    /**
     * The waiter this waitable belongs to, if any.
     */
    Waiter* waiter;

    /**
     * The file descriptor
     */
    int fd;

    /**
     * The events this waitable is interested in.
     */
    short events;

protected:
    /**
     * Construct the waitable.
     */
    Waitable(Waiter* waiter, int fd = -1, short events = 0);

public:
    /**
     * Destroy the waitable. It will be removed from the waiter.
     */
    virtual ~Waitable();

    /**
     * Indicate if the waitable is ready, i.e. there is no need to
     * wait for it.
     *
     * Calling this function should not deleted the ready
     * indication. It should be deleted by actually processing the data.
     */
    virtual bool ready() = 0;

protected:
    /**
     * Handle the given events.
     */
    virtual void handleEvents(short events) = 0;

    friend class Waiter;
};

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

} /* namespace xplcommon::posix */ } /* namespace xplcommon */

//------------------------------------------------------------------------------
#endif // XPLCOMMON_POSIXWAITABLE_H

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