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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
#include "qtlockedfile.h"
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
namespace SharedTools {
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;
remove();
return true;
}
QtLockedFile::~QtLockedFile()
{
if (isOpen())
unlock();
}
} // namespace SharedTools
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