--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/qtmobility/src/publishsubscribe/qsystemreadwritelock_win.cpp Fri Apr 16 15:51:22 2010 +0300
@@ -0,0 +1,330 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the Qt Mobility Components.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** 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 Technology Preview License Agreement accompanying
+** this package.
+**
+** 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 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qsystemreadwritelock_p.h"
+
+#include <QSharedMemory>
+#include <QSystemSemaphore>
+
+///#define QSYSTEMREADWRITELOCK_DEBUG 1
+#ifdef QSYSTEMREADWRITELOCK_DEBUG
+#include <QDebug>
+#endif
+
+QT_USE_NAMESPACE
+
+QTM_BEGIN_NAMESPACE
+
+class QSystemReadWriteLockPrivate
+{
+public:
+ QSystemReadWriteLockPrivate(const QString &key, QSystemReadWriteLock::AccessMode mode);
+ ~QSystemReadWriteLockPrivate();
+
+ int &accessCount();
+ unsigned int &waitingReaders();
+ unsigned int &waitingWriters();
+
+ QSystemReadWriteLock::SystemReadWriteLockError convertError(QSystemSemaphore::SystemSemaphoreError error);
+ QSystemReadWriteLock::SystemReadWriteLockError convertError(QSharedMemory::SharedMemoryError error);
+
+ QString m_key;
+
+ QSharedMemory m_counts;
+ QSystemSemaphore m_readerWait;
+ QSystemSemaphore m_writerWait;
+ bool m_isInitialized;
+
+ QSystemReadWriteLock::SystemReadWriteLockError m_error;
+ QString m_errorString;
+};
+
+QSystemReadWriteLockPrivate::QSystemReadWriteLockPrivate(const QString &key, QSystemReadWriteLock::AccessMode mode)
+ :m_key(key), m_counts(key + QLatin1String("_counts")),
+ m_readerWait(key + QLatin1String("_readerWait"), 0, (mode==QSystemReadWriteLock::Create)?QSystemSemaphore::Create:QSystemSemaphore::Open),
+ m_writerWait(key + QLatin1String("_writerWait"), 0, (mode==QSystemReadWriteLock::Create)?QSystemSemaphore::Create:QSystemSemaphore::Open),
+ m_isInitialized(false), m_error(QSystemReadWriteLock::NoError), m_errorString(QString())
+{
+ bool isAttached = false;
+ int retries=5;
+ for (int i=0; i < retries; ++i){
+ if (m_counts.attach()) {
+ isAttached = true;
+ break;
+ }
+ else {
+ if (m_counts.error() == QSharedMemory::NotFound) {
+ if (m_counts.create(3 * sizeof(int))) {
+ isAttached = true;
+ break;
+ }
+ }
+ }
+ }
+
+ if (!isAttached) {
+ m_error = convertError(m_counts.error());
+ m_errorString = QObject::tr("QSystemReadWriteLockPrivate::QSystemReadWriteLockPrivate: "
+ "Unable to create/attach to shared memory");
+ return;
+ } else {
+ if (mode == QSystemReadWriteLock::Create) {
+ if(!m_counts.lock()) {
+ m_error = convertError(m_counts.error());
+ m_errorString = QObject::tr("QSystemReadWriteLockPrivate::QSystemReadWriteLockPrivate: "
+ "Unable to initialize shared memory");
+ return;
+ }
+ int * data = (int *)m_counts.data();
+ ::memset(data, 0, 3 * sizeof(int));
+ m_counts.unlock();
+ }
+ m_isInitialized = true;
+ }
+}
+
+QSystemReadWriteLockPrivate::~QSystemReadWriteLockPrivate()
+{
+}
+
+QSystemReadWriteLock::SystemReadWriteLockError QSystemReadWriteLockPrivate::convertError(QSystemSemaphore::SystemSemaphoreError error)
+{
+ switch(error) {
+ case QSystemSemaphore::NoError:
+ return QSystemReadWriteLock::NoError;
+ case QSystemSemaphore::PermissionDenied:
+ return QSystemReadWriteLock::PermissionDenied;
+ case QSystemSemaphore::KeyError:
+ return QSystemReadWriteLock::KeyError;
+ case QSystemSemaphore::NotFound:
+ return QSystemReadWriteLock::NotFound;
+ case QSystemSemaphore::OutOfResources:
+ return QSystemReadWriteLock::OutOfResources;
+ case QSystemSemaphore::AlreadyExists:
+ case QSystemSemaphore::UnknownError:
+ default:
+ return QSystemReadWriteLock::UnknownError;
+ }
+}
+
+QSystemReadWriteLock::SystemReadWriteLockError QSystemReadWriteLockPrivate::convertError(QSharedMemory::SharedMemoryError error)
+{
+ switch(error){
+ case QSharedMemory::NoError:
+ return QSystemReadWriteLock::NoError;
+ case QSharedMemory::PermissionDenied:
+ return QSystemReadWriteLock::PermissionDenied;
+ case QSharedMemory::KeyError:
+ return QSystemReadWriteLock::KeyError;
+ case QSharedMemory::NotFound:
+ return QSystemReadWriteLock::NotFound;
+ case QSharedMemory::LockError:
+ return QSystemReadWriteLock::LockError;
+ case QSharedMemory::UnknownError:
+ default:
+ return QSystemReadWriteLock::UnknownError;
+ }
+}
+
+QSystemReadWriteLock::QSystemReadWriteLock(const QString &key, AccessMode mode)
+ :d(new QSystemReadWriteLockPrivate(key,mode))
+{
+}
+
+QSystemReadWriteLock::~QSystemReadWriteLock()
+{
+ Q_ASSERT(d);
+ delete d;
+ d = 0;
+}
+
+bool QSystemReadWriteLock::lockForRead()
+{
+#if defined QSYSTEMREADWRITELOCK_DEBUG
+ qDebug() << "QSystemReadWriteLock::lockForRead() <start>\naccessCount ="
+ << d->accessCount() << "\twaitingWriters=" << d->waitingWriters() << "\twaitingReaders=" << d->waitingReaders();
+#endif
+ if (!d->m_isInitialized) {
+ d->m_error = QSystemReadWriteLock::FailedToInitialize;
+ d->m_errorString = QObject::tr("QSystemReadWriteLock::lockForRead(): cannot peform operation, lock initialization had not been successful");
+ return false;
+ }
+
+ if(!d->m_counts.lock()) {
+ d->m_error = d->convertError(d->m_counts.error());
+ d->m_errorString = QObject::tr("QSystemReadWriteLock::lockForRead(): cannot perform operation, locking of shared memory was unsuccessful");
+ return false;
+ }
+
+ while(d->accessCount() < 0 || d->waitingWriters() > 0 ) {
+ ++d->waitingReaders();
+ d->m_counts.unlock();
+ d->m_readerWait.acquire();
+ d->m_counts.lock();
+ --d->waitingReaders();
+ }
+ ++d->accessCount();
+ Q_ASSERT_X(d->accessCount() > 0, "QSystemReadWriteLock::lockForRead()", "Overflow in lock counter");
+#if defined QSYSTEMREADWRITELOCK_DEBUG
+ qDebug() << "QSystemReadWriteLock::lockForRead() <end>\naccessCount ="
+ << d->accessCount() << "\twaitingWriters=" << d->waitingWriters() << "\twaitingReaders=" << d->waitingReaders();
+#endif
+
+ d->m_error = QSystemReadWriteLock::NoError;
+ d->m_errorString.clear();
+ d->m_counts.unlock();
+ return true;
+}
+
+bool QSystemReadWriteLock::lockForWrite()
+{
+#if defined QSYSTEMREADWRITELOCK_DEBUG
+ qDebug() << "QSystemReadWriteLock::lockForWrite() <start>\naccessCount ="
+ << d->accessCount() << "\twaitingWriters=" << d->waitingWriters() << "\twaitingReaders=" << d->waitingReaders();
+#endif
+ if (!d->m_isInitialized) {
+ d->m_error = QSystemReadWriteLock::FailedToInitialize;
+ d->m_errorString = QObject::tr("QSystemReadWriteLock::lockForWrite(): cannot peform operation, lock initialization had not been successful");
+ return false;
+ }
+
+ if(!d->m_counts.lock()) {
+ d->m_error = d->convertError(d->m_counts.error());
+ d->m_errorString = QObject::tr("QSystemReadWriteLock::lockForwrite(): cannot perform operation, locking of shared memory was unsuccessful");
+ return false;
+ }
+
+#if defined QSYSTEMREADWRITELOCK_DEBUG
+ qDebug() << "QSystemReadWriteLock::lockForWrite() <start>\naccessCount ="
+ << d->accessCount() << "\twaitingWriters=" << d->waitingWriters() << "\twaitingReaders=" << d->waitingReaders();
+#endif
+ while(d->accessCount() != 0) {
+ ++d->waitingWriters();
+ d->m_counts.unlock();
+ d->m_writerWait.acquire();
+ d->m_counts.lock();
+ --d->waitingWriters();
+ }
+ --d->accessCount();
+#if defined QSYSTEMREADWRITELOCK_DEBUG
+ qDebug() << "QSystemReadWriteLock::lockForWrite() <end>\naccessCount ="
+ << d->accessCount() << "\twaitingWriters=" << d->waitingWriters() << "\twaitingReaders=" << d->waitingReaders();
+#endif
+
+ Q_ASSERT_X(d->accessCount() < 0, "QSystemReadWriteLock::lockForWrite()", "Overflow in lock counter");
+
+ d->m_error = QSystemReadWriteLock::NoError;
+ d->m_errorString.clear();
+ d->m_counts.unlock();
+ return true;
+}
+
+void QSystemReadWriteLock::unlock()
+{
+ if (!d->m_isInitialized) {
+ d->m_error = QSystemReadWriteLock::FailedToInitialize;
+ d->m_errorString = QObject::tr("QSystemReadWriteLock::unlock(): cannot peform operation, lock initialization had not been successful");
+ return;
+ }
+
+ if(!d->m_counts.lock()) {
+ d->m_error = d->convertError(d->m_counts.error());
+ d->m_errorString = QObject::tr("QSystemReadWriteLock::lockForwrite(): cannot perform operation, locking of shared memory was unsuccessful");
+ return;
+ }
+
+ Q_ASSERT_X(d->accessCount() != 0, "QSystemReadWriteLock::unlock()", "Cannot unlock an unlocked lock");
+
+ bool unlocked = false;
+ if (d->accessCount() > 0) {
+ unlocked = --d->accessCount() == 0;
+ } else if (d->accessCount() < 0 && ++d->accessCount() == 0) {
+ unlocked = true;
+ }
+
+ if (unlocked) {
+ if (d->waitingWriters() > 0 ) {
+ d->m_writerWait.release();
+ } else if (d->waitingReaders()) {
+ d->m_readerWait.release(d->waitingReaders());
+ }
+ }
+#if defined QSYSTEMREADWRITELOCK_DEBUG
+ qDebug() << "QSystemReadWriteLock::unlock() <end>\naccessCount ="
+ << d->accessCount() << "\twaitingWriters=" << d->waitingWriters() << "\twaitingReaders=" << d->waitingReaders();
+#endif
+ d->m_error = QSystemReadWriteLock::NoError;
+ d->m_errorString.clear();
+ d->m_counts.unlock();
+ return;
+}
+
+int& QSystemReadWriteLockPrivate::accessCount()
+{
+ return *((int *)m_counts.data());
+}
+
+unsigned int &QSystemReadWriteLockPrivate::waitingReaders()
+{
+ return *(((unsigned int*)m_counts.data())+1);
+}
+
+unsigned int &QSystemReadWriteLockPrivate::waitingWriters()
+{
+ return *(((unsigned int*)m_counts.data())+2);
+}
+
+QSystemReadWriteLock::SystemReadWriteLockError QSystemReadWriteLock::error() const
+{
+ return d->m_error;
+}
+
+QString QSystemReadWriteLock::errorString() const
+{
+ return d->m_errorString;
+}
+
+QString QSystemReadWriteLock::key() const
+{
+ return d->m_key;
+}
+
+QTM_END_NAMESPACE