MUtilities/src/DirLocker.h
2016-02-20 16:30:17 +01:00

122 lines
3.0 KiB
C++

///////////////////////////////////////////////////////////////////////////////
// MuldeR's Utilities for Qt
// Copyright (C) 2004-2016 LoRd_MuldeR <MuldeR2@GMX.de>
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
//
// http://www.gnu.org/licenses/lgpl-2.1.txt
//////////////////////////////////////////////////////////////////////////////////
#pragma once
//MUtils
#include <MUtils/Global.h>
//StdLib
#include <stdexcept>
//Qt
#include <QString>
#include <QFile>
///////////////////////////////////////////////////////////////////////////////
// Directory Locker
///////////////////////////////////////////////////////////////////////////////
namespace MUtils
{
namespace Internal
{
class DirLockException : public std::runtime_error
{
public:
DirLockException(const char *const message)
:
std::runtime_error(message)
{
}
};
class DirLock
{
public:
DirLock(const QString dirPath)
:
m_dirPath(dirPath)
{
bool okay = false;
const QByteArray testData = QByteArray(TEST_DATA);
if(m_dirPath.isEmpty())
{
throw DirLockException("Path must not be empty!");
}
for(int i = 0; i < 32; i++)
{
m_lockFile.reset(new QFile(QString("%1/~%2.lck").arg(m_dirPath, MUtils::rand_str())));
if(m_lockFile->open(QIODevice::WriteOnly | QIODevice::Truncate | QIODevice::Unbuffered))
{
if(m_lockFile->write(testData) >= testData.size())
{
if(m_lockFile->error() == QFile::NoError)
{
okay = true;
break;
}
}
m_lockFile->remove();
}
}
if(!okay)
{
throw DirLockException("Locking has failed!");
}
}
~DirLock(void)
{
bool okay = false;
if(!m_lockFile.isNull())
{
for(int i = 0; i < 16; i++)
{
if(m_lockFile->remove() || (!m_lockFile->exists()))
{
okay = true;
break;
}
OS::sleep_ms(125);
}
}
if(!okay)
{
qWarning("DirLock: The lock file could not be removed!");
}
}
inline const QString &getPath(void) const
{
return m_dirPath;
}
private:
static const char *const TEST_DATA;
const QString m_dirPath;
QScopedPointer<QFile> m_lockFile;
};
const char *const DirLock::TEST_DATA = "7QtDxPWotHGQYv1xHyQHFKjTB5u5VYKHE20NMDAgLRYoy16CZN7mEYijbjCJpORnoBbtHCzqyy1a6BLCMMiTUZpLzgjg4qnN505egUBqk3wMhPsYjFpkng9i37mWd1iF";
}
}