114 lines
3.4 KiB
C++
114 lines
3.4 KiB
C++
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/****************************************************************************
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**
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** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies)
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** 2020 KylinSoft Co., Ltd.
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** Contact: http://www.qt-project.org/legal
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**
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** This file is part of the Qt Solutions component.
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**
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** $QT_BEGIN_LICENSE:BSD$
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** You may use this file under the terms of the BSD license as follows:
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**
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** "Redistribution and use in source and binary forms, with or without
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** modification, are permitted provided that the following conditions are
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** met:
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** * Redistributions of source code must retain the above copyright
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** notice, this list of conditions and the following disclaimer.
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** * Redistributions in binary form must reproduce the above copyright
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** notice, this list of conditions and the following disclaimer in
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** the documentation and/or other materials provided with the
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** distribution.
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** * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
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** of its contributors may be used to endorse or promote products derived
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** from this software without specific prior written permission.
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**
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**
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** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
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**
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** $QT_END_LICENSE$
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**
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****************************************************************************/
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#include <string.h>
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#include <errno.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include "qt-locked-file.h"
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bool QtLockedFile::lock(LockMode mode, bool block) {
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if(!isOpen()) {
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qWarning("QtLockedFile::lock(): file is not opened");
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return false;
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}
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if(mode == NoLock)
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return unlock();
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if(mode == m_lock_mode)
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return true;
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if(m_lock_mode != NoLock)
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unlock();
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struct flock fl;
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fl.l_whence = SEEK_SET;
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fl.l_start = 0;
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fl.l_len = 0;
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fl.l_type = (mode == ReadLock) ? F_RDLCK : F_WRLCK;
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int cmd = block ? F_SETLKW : F_SETLK;
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int ret = fcntl(handle(), cmd, &fl);
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if(ret == -1) {
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if(errno != EINTR && errno != EAGAIN)
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qWarning("QtLockedFile::lock(): fcntl: %s", strerror(errno));
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return false;
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}
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m_lock_mode = mode;
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return true;
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}
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bool QtLockedFile::unlock() {
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if(!isOpen()) {
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qWarning("QtLockedFile::unlock(): file is not opened");
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return false;
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}
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if(!isLocked())
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return true;
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struct flock fl;
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fl.l_whence = SEEK_SET;
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fl.l_start = 0;
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fl.l_len = 0;
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fl.l_type = F_UNLCK;
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int ret = fcntl(handle(), F_SETLKW, &fl);
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if(ret == -1) {
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qWarning("QtLockedFile::lock(): fcntl: %s", strerror(errno));
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return false;
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}
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m_lock_mode = NoLock;
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return true;
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}
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QtLockedFile::~QtLockedFile() {
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if(isOpen())
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unlock();
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}
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