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/****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the Qt Solutions component.
**
** $QT_BEGIN_LICENSE:BSD$
** 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 Digia Plc 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."
**
** $QT_END_LICENSE$
**
****************************************************************************/
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include "qtlockedfile.h"
bool QtLockedFile::lock(LockMode mode, bool block)
{
if (!isOpen()) {
qWarning("QtLockedFile::lock(): file is not opened");
return false;
}
if (mode == NoLock)
return unlock();
if (mode == m_lock_mode)
return true;
if (m_lock_mode != NoLock)
unlock();
struct flock fl;
fl.l_whence = SEEK_SET;
fl.l_start = 0;
fl.l_len = 0;
fl.l_type = (mode == ReadLock) ? F_RDLCK : F_WRLCK;
int cmd = block ? F_SETLKW : F_SETLK;
int ret = fcntl(handle(), cmd, &fl);
if (ret == -1) {
if (errno != EINTR && errno != EAGAIN)
qWarning("QtLockedFile::lock(): fcntl: %s", strerror(errno));
return false;
}
m_lock_mode = mode;
return true;
}
bool QtLockedFile::unlock()
{
if (!isOpen()) {
qWarning("QtLockedFile::unlock(): file is not opened");
return false;
}
if (!isLocked())
return true;
struct flock fl;
fl.l_whence = SEEK_SET;
fl.l_start = 0;
fl.l_len = 0;
fl.l_type = F_UNLCK;
int ret = fcntl(handle(), F_SETLKW, &fl);
if (ret == -1) {
qWarning("QtLockedFile::lock(): fcntl: %s", strerror(errno));
return false;
}
m_lock_mode = NoLock;
return true;
}
QtLockedFile::~QtLockedFile()
{
if (isOpen())
unlock();
}
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