--- /dev/null
+/****************************************************************************
+**
+** 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 a Qt Solutions component.
+**
+** Commercial Usage
+** Licensees holding valid Qt Commercial licenses may use this file in
+** accordance with the Qt Solutions Commercial License Agreement provided
+** with the Software or, alternatively, in accordance with the terms
+** contained in a written agreement between you and Nokia.
+**
+** 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.
+**
+** 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.
+**
+** Please note Third Party Software included with Qt Solutions may impose
+** additional restrictions and it is the user's responsibility to ensure
+** that they have met the licensing requirements of the GPL, LGPL, or Qt
+** Solutions Commercial license and the relevant license of the Third
+** Party Software they are using.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact Nokia at qt-info@nokia.com.
+**
+****************************************************************************/
+
+#include "qtlockedfile.h"
+#include <qt_windows.h>
+#include <QtCore/QFileInfo>
+
+#define MUTEX_PREFIX "QtLockedFile mutex "
+// Maximum number of concurrent read locks. Must not be greater than MAXIMUM_WAIT_OBJECTS
+#define MAX_READERS MAXIMUM_WAIT_OBJECTS
+
+Qt::HANDLE QtLockedFile::getMutexHandle(int idx, bool doCreate)
+{
+ if (mutexname.isEmpty()) {
+ QFileInfo fi(*this);
+ mutexname = QString::fromLatin1(MUTEX_PREFIX)
+ + fi.absoluteFilePath().toLower();
+ }
+ QString mname(mutexname);
+ if (idx >= 0)
+ mname += QString::number(idx);
+
+ Qt::HANDLE mutex;
+ if (doCreate) {
+ QT_WA( { mutex = CreateMutexW(NULL, FALSE, (TCHAR*)mname.utf16()); },
+ { mutex = CreateMutexA(NULL, FALSE, mname.toLocal8Bit().constData()); } );
+ if (!mutex) {
+ qErrnoWarning("QtLockedFile::lock(): CreateMutex failed");
+ return 0;
+ }
+ }
+ else {
+ QT_WA( { mutex = OpenMutexW(SYNCHRONIZE | MUTEX_MODIFY_STATE, FALSE, (TCHAR*)mname.utf16()); },
+ { mutex = OpenMutexA(SYNCHRONIZE | MUTEX_MODIFY_STATE, FALSE, mname.toLocal8Bit().constData()); } );
+ if (!mutex) {
+ if (GetLastError() != ERROR_FILE_NOT_FOUND)
+ qErrnoWarning("QtLockedFile::lock(): OpenMutex failed");
+ return 0;
+ }
+ }
+ return mutex;
+}
+
+bool QtLockedFile::waitMutex(Qt::HANDLE mutex, bool doBlock)
+{
+ Q_ASSERT(mutex);
+ DWORD res = WaitForSingleObject(mutex, doBlock ? INFINITE : 0);
+ switch (res) {
+ case WAIT_OBJECT_0:
+ case WAIT_ABANDONED:
+ return true;
+ break;
+ case WAIT_TIMEOUT:
+ break;
+ default:
+ qErrnoWarning("QtLockedFile::lock(): WaitForSingleObject failed");
+ }
+ return false;
+}
+
+
+
+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();
+
+ if (!wmutex && !(wmutex = getMutexHandle(-1, true)))
+ return false;
+
+ if (!waitMutex(wmutex, block))
+ return false;
+
+ if (mode == ReadLock) {
+ int idx = 0;
+ for (; idx < MAX_READERS; idx++) {
+ rmutex = getMutexHandle(idx, false);
+ if (!rmutex || waitMutex(rmutex, false))
+ break;
+ CloseHandle(rmutex);
+ }
+ bool ok = true;
+ if (idx >= MAX_READERS) {
+ qWarning("QtLockedFile::lock(): too many readers");
+ rmutex = 0;
+ ok = false;
+ }
+ else if (!rmutex) {
+ rmutex = getMutexHandle(idx, true);
+ if (!rmutex || !waitMutex(rmutex, false))
+ ok = false;
+ }
+ if (!ok && rmutex) {
+ CloseHandle(rmutex);
+ rmutex = 0;
+ }
+ ReleaseMutex(wmutex);
+ if (!ok)
+ return false;
+ }
+ else {
+ Q_ASSERT(rmutexes.isEmpty());
+ for (int i = 0; i < MAX_READERS; i++) {
+ Qt::HANDLE mutex = getMutexHandle(i, false);
+ if (mutex)
+ rmutexes.append(mutex);
+ }
+ if (rmutexes.size()) {
+ DWORD res = WaitForMultipleObjects(rmutexes.size(), rmutexes.constData(),
+ TRUE, block ? INFINITE : 0);
+ if (res != WAIT_OBJECT_0 && res != WAIT_ABANDONED) {
+ if (res != WAIT_TIMEOUT)
+ qErrnoWarning("QtLockedFile::lock(): WaitForMultipleObjects failed");
+ m_lock_mode = WriteLock; // trick unlock() to clean up - semiyucky
+ unlock();
+ 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;
+
+ if (m_lock_mode == ReadLock) {
+ ReleaseMutex(rmutex);
+ CloseHandle(rmutex);
+ rmutex = 0;
+ }
+ else {
+ foreach(Qt::HANDLE mutex, rmutexes) {
+ ReleaseMutex(mutex);
+ CloseHandle(mutex);
+ }
+ rmutexes.clear();
+ ReleaseMutex(wmutex);
+ }
+
+ m_lock_mode = QtLockedFile::NoLock;
+ return true;
+}
+
+QtLockedFile::~QtLockedFile()
+{
+ if (isOpen())
+ unlock();
+ if (wmutex)
+ CloseHandle(wmutex);
+}
OSDN Git Service
