/****************************************************************************

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** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).

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** appearing in the file LICENSE.LGPL included in the packaging of this

** file. Please review the following information to ensure the GNU Lesser

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** rights. These rights are described in the Nokia Qt LGPL Exception

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** Alternatively, this file may be used under the terms of the GNU General

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** file. Please review the following information to ensure the GNU General

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****************************************************************************/

#include "qsystemsemaphore.h"

#include "qsystemsemaphore_p.h"

#include "qcoreapplication.h"

#include <qdebug.h>

#ifndef QT_NO_SYSTEMSEMAPHORE

//#define QSYSTEMSEMAPHORE_DEBUG

QT_BEGIN_NAMESPACE

QSystemSemaphorePrivate::QSystemSemaphorePrivate() :

    semaphore(0), error(QSystemSemaphore::NoError)

{

}

void QSystemSemaphorePrivate::setErrorString(const QString &function)

{

    DWORD windowsError = GetLastError();

    if (windowsError == 0)

        return;

    switch (windowsError) {

    case ERROR_NO_SYSTEM_RESOURCES:

    case ERROR_NOT_ENOUGH_MEMORY:

        error = QSystemSemaphore::OutOfResources;

        errorString = QCoreApplication::translate("QSystemSemaphore", "%1: out of resources").arg(function);

        break;

    case ERROR_ACCESS_DENIED:

        error = QSystemSemaphore::PermissionDenied;

        errorString = QCoreApplication::translate("QSystemSemaphore", "%1: permission denied").arg(function);

        break;

    default:

        errorString = QCoreApplication::translate("QSystemSemaphore", "%1: unknown error %2").arg(function).arg(windowsError);

        error = QSystemSemaphore::UnknownError;

#ifdef QSYSTEMSEMAPHORE_DEBUG

        qDebug() << errorString << "key" << key;

#endif

        break;

    }

}

HANDLE QSystemSemaphorePrivate::handle(QSystemSemaphore::AccessMode)

{

    // don't allow making handles on empty keys

    if (key.isEmpty())

        return 0;

    // Create it if it doesn't already exists.

    if (semaphore == 0) {

        semaphore = CreateSemaphore(0, initialValue, MAXLONG, (wchar_t*)fileName.utf16());

        if (semaphore == NULL)

            setErrorString(QLatin1String("QSystemSemaphore::handle"));

    }

    return semaphore;

}

void QSystemSemaphorePrivate::cleanHandle()

{

    if (semaphore && !CloseHandle(semaphore)) {

#if defined QSYSTEMSEMAPHORE_DEBUG

        qDebug() << QLatin1String("QSystemSemaphorePrivate::CloseHandle: sem failed");

#endif

    }

    semaphore = 0;

}

bool QSystemSemaphorePrivate::modifySemaphore(int count)

{

    if (0 == handle())

        return false;

    if (count > 0) {

        if (0 == ReleaseSemaphore(semaphore, count, 0)) {

            setErrorString(QLatin1String("QSystemSemaphore::modifySemaphore"));

#if defined QSYSTEMSEMAPHORE_DEBUG

            qDebug() << QLatin1String("QSystemSemaphore::modifySemaphore ReleaseSemaphore failed");

#endif

            return false;

        }

    } else {

        if (WAIT_OBJECT_0 != WaitForSingleObject(semaphore, INFINITE)) {

            setErrorString(QLatin1String("QSystemSemaphore::modifySemaphore"));

#if defined QSYSTEMSEMAPHORE_DEBUG

            qDebug() << QLatin1String("QSystemSemaphore::modifySemaphore WaitForSingleObject failed");

#endif

            return false;

        }

    }

    return true;

}

QT_END_NAMESPACE

#endif // QT_NO_SYSTEMSEMAPHORE