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/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the test suite of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the either Technology Preview License Agreement or the
** Beta Release License Agreement.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain
** additional rights. These rights are described in the Nokia Qt LGPL
** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
** package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at http://www.qtsoftware.com/contact.
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qsystemlock.h"
#include "qsystemlock_p.h"
#include <qdebug.h>
#include <QtCore>
QSystemLockPrivate::QSystemLockPrivate() :
semaphore(0), semaphoreLock(0),
lockCount(0), error(QSystemLock::NoError)
{
}
void QSystemLockPrivate::setErrorString(const QString &function)
{
BOOL windowsError = GetLastError();
if (windowsError == 0)
return;
errorString = function + QLatin1String(": ")
+ QLatin1String("Unknown error");
error = QSystemLock::UnknownError;
qWarning() << errorString << "key" << key << (int)windowsError << semaphore << semaphoreLock;
}
/*!
\internal
Setup the semaphore
*/
HANDLE QSystemLockPrivate::handle()
{
// don't allow making handles on empty keys
if (key.isEmpty())
return 0;
// Create it if it doesn't already exists.
if (semaphore == 0) {
QString safeName = makeKeyFileName();
QT_WA({
semaphore = CreateSemaphoreW(0, MAX_LOCKS, MAX_LOCKS, (TCHAR*)safeName.utf16());
}, {
semaphore = CreateSemaphoreA(0, MAX_LOCKS, MAX_LOCKS, safeName.toLocal8Bit().constData());
});
if (semaphore == 0) {
setErrorString(QLatin1String("QSystemLockPrivate::handle"));
return 0;
}
}
if (semaphoreLock == 0) {
QString safeLockName = QSharedMemoryPrivate::makePlatformSafeKey(key + QLatin1String("lock"), QLatin1String("qipc_systemlock_"));
QT_WA({
semaphoreLock = CreateSemaphoreW(0,
1, 1, (TCHAR*)safeLockName.utf16());
}, {
semaphoreLock = CreateSemaphoreA(0,
1, 1, safeLockName.toLocal8Bit().constData());
});
if (semaphoreLock == 0) {
setErrorString(QLatin1String("QSystemLockPrivate::handle"));
return 0;
}
}
return semaphore;
}
/*!
\internal
Cleanup the semaphore
*/
void QSystemLockPrivate::cleanHandle()
{
if (semaphore && !CloseHandle(semaphore))
setErrorString(QLatin1String("QSystemLockPrivate::cleanHandle:"));
if (semaphoreLock && !CloseHandle(semaphoreLock))
setErrorString(QLatin1String("QSystemLockPrivate::cleanHandle:"));
semaphore = 0;
semaphoreLock = 0;
}
bool QSystemLockPrivate::lock(HANDLE handle, int count)
{
if (count == 1) {
WaitForSingleObject(handle, INFINITE);
return true;
}
int i = count;
while (i > 0) {
if (WAIT_OBJECT_0 == WaitForSingleObject(handle, 0)) {
--i;
} else {
// undo what we have done, sleep and then try again later
ReleaseSemaphore(handle, (count - i), 0);
i = count;
ReleaseSemaphore(semaphoreLock, 1, 0);
Sleep(1);
WaitForSingleObject(semaphoreLock, INFINITE);
}
}
return true;
}
bool QSystemLockPrivate::unlock(HANDLE handle, int count)
{
if (0 == ReleaseSemaphore(handle, count, 0)) {
setErrorString(QLatin1String("QSystemLockPrivate::unlock"));
return false;
}
return true;
}
/*!
\internal
modifySemaphore handles recursive behavior and modifies the semaphore.
*/
bool QSystemLockPrivate::modifySemaphore(QSystemLockPrivate::Operation op,
QSystemLock::LockMode mode)
{
if (0 == handle())
return false;
if ((lockCount == 0 && op == Lock) || (lockCount > 0 && op == Unlock)) {
if (op == Unlock) {
--lockCount;
Q_ASSERT(lockCount >= 0);
if (lockCount > 0)
return true;
}
int count = (mode == QSystemLock::ReadWrite) ? MAX_LOCKS : 1;
if (op == Lock) {
lock(semaphoreLock, 1);
lock(semaphore, count);
if (count != MAX_LOCKS) unlock(semaphoreLock, 1);
lockedMode = mode;
} else {
if (count == MAX_LOCKS) unlock(semaphoreLock, 1);
unlock(semaphore, count);
}
}
if (op == Lock)
lockCount++;
return true;
}
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