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

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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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** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.

**

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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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** 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

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

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

#include "qsharedmemory.h"

#include "qsharedmemory_p.h"

#include <qdebug.h>

#ifndef QT_NO_SHAREDMEMORY

//#define QSHAREDMEMORY_DEBUG

QT_BEGIN_NAMESPACE

QSharedMemoryPrivate::QSharedMemoryPrivate()

    : QObjectPrivate(), memory(0), size(0), error(QSharedMemory::NoError),

#ifndef QT_NO_SYSTEMSEMAPHORE

      systemSemaphore(QString()), lockedByMe(false),

#endif

      hand(0)

{

}

void QSharedMemoryPrivate::setErrorString(const QString &function)

{

    DWORD windowsError = GetLastError();

    if (windowsError == 0)

        return;

    switch (windowsError) {

    case ERROR_ALREADY_EXISTS:

        error = QSharedMemory::AlreadyExists;

        errorString = QSharedMemory::tr("%1: already exists").arg(function);

    break;

    case ERROR_FILE_NOT_FOUND:

#ifdef Q_OS_WINCE

        // This happens on CE only if no file is present as CreateFileMappingW

        // bails out with this error code

    case ERROR_INVALID_PARAMETER:

#endif

        error = QSharedMemory::NotFound;

        errorString = QSharedMemory::tr("%1: doesn't exist").arg(function);

        break;

    case ERROR_COMMITMENT_LIMIT:

        error = QSharedMemory::InvalidSize;

        errorString = QSharedMemory::tr("%1: invalid size").arg(function);

        break;

    case ERROR_NO_SYSTEM_RESOURCES:

    case ERROR_NOT_ENOUGH_MEMORY:

        error = QSharedMemory::OutOfResources;

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

        break;

    case ERROR_ACCESS_DENIED:

        error = QSharedMemory::PermissionDenied;

        errorString = QSharedMemory::tr("%1: permission denied").arg(function);

        break;

    default:

        errorString = QSharedMemory::tr("%1: unknown error %2").arg(function).arg(windowsError);

        error = QSharedMemory::UnknownError;

#ifdef QSHAREDMEMORY_DEBUG

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

#endif

        break;

    }

}

HANDLE QSharedMemoryPrivate::handle()

{

    if (!hand) {

        // don't allow making handles on empty keys

        if (nativeKey.isEmpty()) {

            error = QSharedMemory::KeyError;

            errorString = QSharedMemory::tr("%1: key is empty").arg(QLatin1String("QSharedMemory::handle"));

            return false;

        }

#ifndef Q_OS_WINCE

        hand = OpenFileMapping(FILE_MAP_ALL_ACCESS, false, (wchar_t*)nativeKey.utf16());

#else

        // This works for opening a mapping too, but always opens it with read/write access in

        // attach as it seems.

        hand = CreateFileMapping(INVALID_HANDLE_VALUE, 0, PAGE_READWRITE, 0, 0, (wchar_t*)nativeKey.utf16());

#endif

        if (!hand)

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

    }

    return hand;

}

void QSharedMemoryPrivate::cleanHandle()

{

    if (hand != 0 && !CloseHandle(hand))

        setErrorString(QLatin1String("QSharedMemory::cleanHandle"));

    hand = 0;

}

bool QSharedMemoryPrivate::create(int size)

{

    if (nativeKey.isEmpty()) {

        error = QSharedMemory::KeyError;

        errorString = QSharedMemory::tr("%1: key is empty").arg(QLatin1String("QSharedMemory::create"));

        return false;

    }

    // Create the file mapping.

    hand = CreateFileMapping(INVALID_HANDLE_VALUE, 0, PAGE_READWRITE, 0, size, (wchar_t*)nativeKey.utf16());

    setErrorString(QLatin1String("QSharedMemory::create"));

    // hand is valid when it already exists unlike unix so explicitly check

    return !(error == QSharedMemory::AlreadyExists || !hand);

}

bool QSharedMemoryPrivate::attach(QSharedMemory::AccessMode mode)

{

    // Grab a pointer to the memory block

    int permissions = (mode == QSharedMemory::ReadOnly ? FILE_MAP_READ : FILE_MAP_ALL_ACCESS);

    memory = (void *)MapViewOfFile(handle(), permissions, 0, 0, 0);

    if (0 == memory) {

        setErrorString(QLatin1String("QSharedMemory::attach"));

        cleanHandle();

        return false;

    }

    // Grab the size of the memory we have been given (a multiple of 4K on windows)

    MEMORY_BASIC_INFORMATION info;

    if (!VirtualQuery(memory, &info, sizeof(info))) {

        // Windows doesn't set an error code on this one,

        // it should only be a kernel memory error.

        error = QSharedMemory::UnknownError;

        errorString = QSharedMemory::tr("%1: size query failed").arg(QLatin1String("QSharedMemory::attach"));

        return false;

    }

    size = info.RegionSize;

    return true;

}

bool QSharedMemoryPrivate::detach()

{

    // umap memory

    if (!UnmapViewOfFile(memory)) {

        setErrorString(QLatin1String("QSharedMemory::detach"));

        return false;

    }

    memory = 0;

    size = 0;

    // close handle

    cleanHandle();

    return true;

}

QT_END_NAMESPACE

#endif // QT_NO_SHAREDMEMORY