source: xplcommon/src/xplcommon/win32/Completer.h@ 22:d13fbc745959

// Copyright (c) 2012 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
// 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
// of the authors and should not be interpreted as representing official policies,
// either expressed or implied, of the FreeBSD Project.

#ifndef XPLCOMMON_WIN32_COMPLETER_H
#define XPLCOMMON_WIN32_COMPLETER_H
//------------------------------------------------------------------------------

#include "Overlapped.h"
#include "Overlappable.h"

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

namespace xplcommon { namespace win32 {

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

/**
 * Base class for objects that handle the completion of some
 * operation. They are associated with an Overlappable, and if that
 * overlappable is non-blocking (i.e. has a waiter), an Overlapped
 * object is created and stored in this object.
 */
class Completer
{
protected:
    /**
     * The overlappable object this completer belongs to.
     */
    Overlappable& overlappable;

    /**
     * The overlapped object.
     */
    Overlapped* overlapped;

protected:
    /**
     * Construct the completer for the given Overlappable.
     */
    Completer(Overlappable* overlappable);

    /**
     * Destroy the completer.
     */
    virtual ~Completer();

    /**
     * Add the overlapped object (if any) to the given waiter.
     */
    void addTo(Waiter* waiter);

    /**
     * Remove the overlapped object (if any) from the waiter it is
     * associated with.
     */
    void removeFromWaiter();

    /**
     * Determine if there is an overlapped object and it is being
     * waited for.
     */
    bool isWaited() const;

    /**
     * Get the result of the overlapped operation, if any.
     *
     * @see Overlapped::getResult
     */
    bool getResult(DWORD& size);

    /**
     * Check whether we are waiting for an overlapped result and if
     * so, return that.
     *
     * @param result will contain the result to return if we are
     * waiting for an overlapped result.
     *
     * @return whether we are waiting for an overlapped result
     */
    bool checkWaitedResult(bool& result);

    /**
     * Handle the given result coming from an overlapped object.
     */
    virtual void handleWaitedResult(DWORD size) = 0;
};

//------------------------------------------------------------------------------
// Inline definitions
//------------------------------------------------------------------------------

inline Completer::Completer(Overlappable* overlappable) :
    overlappable(*overlappable),
    overlapped((overlappable->waiter==0) ? 0 : new Overlapped(*overlappable))
{
}

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

inline Completer::~Completer()
{
    delete overlapped;
}

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

inline void Completer::addTo(Waiter* waiter)
{
    if (overlapped!=0 && waiter!=0) overlapped->addTo(*waiter);
}

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

inline void Completer::removeFromWaiter()
{
    if (overlapped!=0) overlapped->removeFromWaiter();
}

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

inline bool Completer::isWaited() const
{
    return overlapped!=0 && overlapped->isWaited();
}

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

inline bool Completer::getResult(DWORD& size)
{
    return overlapped!=0 && overlapped->getResult(size, overlappable.handle);
}

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

inline bool Completer::checkWaitedResult(bool& result)
{
    if (!isWaited()) {
        return false;
    }

    DWORD size = 0;
    result = getResult(size);

    if (result) {
        removeFromWaiter();
        handleWaitedResult(size);
    } else if (overlappable.failed()) {
        removeFromWaiter();
    }

    return true;
}

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

} /* namespace xplcommon::win32 */ } /* namespace xplcommon */

//------------------------------------------------------------------------------
#endif // XPLCOMMON_WIN32_COMPLETER_H

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