FileLoader.cpp Example File

    /****************************************************************************
     **
     ** Portions Copyright (C) 2012 Research In Motion Limited.
     ** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
     ** All rights reserved.
     ** Contact: Research In Motion Ltd. (http://www.rim.com/company/contact/)
     ** Contact: Nokia Corporation (qt-info@nokia.com)
     **
     ** This file is part of the examples of the BB10 Platform and is derived
     ** from a similar file that is part of the Qt Toolkit.
     **
     ** You may use this file under the terms of the BSD license as follows:
     **
     ** "Redistribution and use in source and binary forms, with or without
     ** modification, are permitted provided that the following conditions are
     ** met:
     **   * Redistributions of source code must retain the above copyright
     **     notice, this list of conditions and the following disclaimer.
     **   * 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.
     **   * Neither the name of Research In Motion, nor the name of Nokia
     **     Corporation and its Subsidiary(-ies), nor the names of its
     **     contributors may be used to endorse or promote products
     **     derived from this software without specific prior written
     **     permission.
     **
     ** 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."
     **
     ****************************************************************************/

    #include "FileLoader.hpp"

    #include <QtCore/QFile>

    /**
     * The key that is used for the shared memory segment.
     * Note: This one must match with the one used in FileLoaderProxy.cpp
     *       in the sharedmemory example.
     */
    static const char *s_sharedKey = "fileloader_shm_key";

    FileLoader::FileLoader(QObject *parent)
        : QObject(parent)
    {
    }

    QString FileLoader::status() const
    {
        return m_status;
    }

    void FileLoader::loadFile(const QString &fileName)
    {
        // Try to open the file ...
        QFile file(QString::fromLatin1("app/native/assets/files/%1").arg(fileName));
        if (!file.open(QIODevice::ReadOnly)) {
            m_status = tr("Unable to open file: %1").arg(file.errorString());
            emit statusChanged();
            return;
        }

        // ... and read its complete content into a temporary variable
        const QByteArray content = file.readAll();
        file.close();

        // Try to attach to the shared memory segment with the given key
        QSharedMemory sharedMemory(QString::fromLatin1(s_sharedKey));
        if (!sharedMemory.attach()) {
            m_status = tr("Unable to attach to shared memory: %1\nPlease start the sharedmemory sample application!").arg(sharedMemory.errorString());
            emit statusChanged();
            return;
        }

        // Lock the shared memory segment before we do any modifications
        sharedMemory.lock();

        // Copy the file content from the temporary variable into the shared memory segment
        strncpy(static_cast<char*>(sharedMemory.data()), content.constData(), sharedMemory.size() - 1);

        // Unlock the shared memory segment again ...
        sharedMemory.unlock();

        // ... and detach from it
        sharedMemory.detach();
        m_status = tr("Loaded file %1 to shared memory").arg(fileName);
        emit statusChanged();
    }