NOISSUE refactor window management and launch, make MultiMC a single instance application.

libraries/LocalPeer/src/LockedFile_win.cpp

@@ -0,0 +1,205 @@
+/****************************************************************************
+**
+** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of the Qt Solutions component.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** You may use this file under the terms of the BSD license as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names
+**     of its contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "LockedFile.h"
+#include <qt_windows.h>
+#include <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 LockedFile::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) {
+		mutex = CreateMutexW(NULL, FALSE, (TCHAR*)mname.utf16());
+		if (!mutex) {
+			qErrnoWarning("QtLockedFile::lock(): CreateMutex failed");
+			return 0;
+		}
+	}
+	else {
+		OpenMutexW(SYNCHRONIZE | MUTEX_MODIFY_STATE, FALSE, (TCHAR*)mname.utf16());
+		if (!mutex) {
+			if (GetLastError() != ERROR_FILE_NOT_FOUND)
+				qErrnoWarning("QtLockedFile::lock(): OpenMutex failed");
+			return 0;
+		}
+	}
+	return mutex;
+}
+
+bool LockedFile::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 LockedFile::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 LockedFile::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 = LockedFile::NoLock;
+	return true;
+}
+
+LockedFile::~LockedFile()
+{
+	if (isOpen())
+		unlock();
+	if (wmutex)
+		CloseHandle(wmutex);
+}