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

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

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** License version 2.1 as published by the Free Software Foundation and

** 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

** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.

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** GNU General Public License Usage

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

** Public License version 3.0 as published by the Free Software Foundation

** and appearing in the file LICENSE.GPL included in the packaging of this

** 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>

#include "qcore_symbian_p.h"

#include <e32cmn.h>

#ifndef QT_NO_SYSTEMSEMAPHORE

//#define QSYSTEMSEMAPHORE_DEBUG

QT_BEGIN_NAMESPACE

QSystemSemaphorePrivate::QSystemSemaphorePrivate() :

    error(QSystemSemaphore::NoError)

{

}

void QSystemSemaphorePrivate::setErrorString(const QString &function, int err)

{

    if (err == KErrNone)

        return;

    switch(err){

    case KErrAlreadyExists:

        errorString = QCoreApplication::tr("%1: already exists", "QSystemSemaphore").arg(function);

        error = QSystemSemaphore::AlreadyExists;

        break;

    case KErrNotFound:

        errorString = QCoreApplication::tr("%1: does not exist", "QSystemSemaphore").arg(function);

        error = QSystemSemaphore::NotFound;

        break;

    case KErrNoMemory:

    case KErrInUse:

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

        error = QSystemSemaphore::OutOfResources;

        break;

    case KErrPermissionDenied:

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

        error = QSystemSemaphore::PermissionDenied;

        break;

    default:

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

        error = QSystemSemaphore::UnknownError;

#ifdef QSYSTEMSEMAPHORE_DEBUG

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

#endif

        break;

    }

}

int QSystemSemaphorePrivate::handle(QSystemSemaphore::AccessMode)

{

    if (semaphore.Handle())

        return semaphore.Handle();

    // don't allow making handles on empty keys

    if (key.isEmpty())

        return 0;

    TPtrC name(qt_QString2TPtrC(fileName));

    int err = KErrAlreadyExists;

    int tryCount = 10;

    // Sort out race conditions by retrying several times until existing handle is acquired.

    // Sometimes opening can fail inexplicably with KErrPermissionDenied many times in a row.

    while (err != KErrNoMemory && err != KErrNone && tryCount-- >= 0) {

        err = semaphore.CreateGlobal(name, initialValue, EOwnerProcess);

        if (err != KErrNoMemory && err != KErrNone)

            err = semaphore.OpenGlobal(name, EOwnerProcess);

    }

    if (err) {

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

        return 0;

    }

    return semaphore.Handle();

}

void QSystemSemaphorePrivate::cleanHandle()

{

    semaphore.Close();

}

bool QSystemSemaphorePrivate::modifySemaphore(int count)

{

    if (0 == handle())

        return false;

    if (count > 0)

        semaphore.Signal(count);

    else

        semaphore.Wait();

    return true;

}

QT_END_NAMESPACE

#endif // QT_NO_SYSTEMSEMAPHORE