QLockedFile.cpp

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/****************************************************************************
 ** Makou Reactor Final Fantasy VII Field Script Editor
 ** Copyright (C) 2009-2012 Arzel Jérôme <myst6re@gmail.com>
 **
 ** This program is free software: you can redistribute it and/or modify
 ** it under the terms of the GNU General Public License as published by
 ** the Free Software Foundation, either version 3 of the License, or
 ** (at your option) any later version.
 **
 ** This program is distributed in the hope that it will be useful,
 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 ** GNU General Public License for more details.
 **
 ** You should have received a copy of the GNU General Public License
 ** along with this program.  If not, see <http://www.gnu.org/licenses/>.
 ****************************************************************************/
#include "QLockedFile.h"

QLockedFile::QLockedFile()
{
}

QLockedFile::QLockedFile(const QString &name) :
    QFile(name)
{
}

QLockedFile::QLockedFile(QObject *parent) :
    QFile(parent)
{
}

QLockedFile::QLockedFile(const QString &name, QObject *parent) :
    QFile(name, parent)
{
}

QLockedFile::~QLockedFile()
{
    close();
}

void QLockedFile::close()
{
    // Unlock file
#ifdef Q_OS_WIN
    CloseHandle(handle);
#else
    ::flock(handle(), LOCK_UN);
#endif
    QFile::close();
}

bool QLockedFile::open(OpenMode mode)
{
    if(!mode.testFlag(QIODevice::ReadOnly)) {
        qWarning() << "QLockedFile::open must be opened in ReadOnly mode";
        return false;
    }

    // Lock file
#ifdef Q_OS_WIN
    handle = CreateFileA(QDir::toNativeSeparators(fileName()).toLatin1().data(),
                         GENERIC_READ,
                         FILE_SHARE_READ,
                         NULL,
                         OPEN_EXISTING,
                         FILE_ATTRIBUTE_NORMAL,
                         NULL);
    if(handle == INVALID_HANDLE_VALUE) {
        qWarning() << "QLockedFile::open error lock";
        return false;
    }

    return QFile::open(mode);
#else
    bool isOpen = QFile::open(mode);

    if(isOpen && ::flock(handle(), LOCK_SH) < 0) {
        qWarning() << "QLockedFile::open error flock";
        return false;
    }

    return isOpen;
#endif
}