From 412855ae3d967ff81a383688397c4d9448a4ee15 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Petr=20Mr=C3=A1zek?= Date: Sun, 30 Oct 2016 02:37:38 +0100 Subject: NOISSUE refactor window management and launch, make MultiMC a single instance application. --- libraries/LocalPeer/src/LockedFile.cpp | 193 +++++++++++++++++++++++++++++++++ 1 file changed, 193 insertions(+) create mode 100644 libraries/LocalPeer/src/LockedFile.cpp (limited to 'libraries/LocalPeer/src/LockedFile.cpp') diff --git a/libraries/LocalPeer/src/LockedFile.cpp b/libraries/LocalPeer/src/LockedFile.cpp new file mode 100644 index 00000000..a4951bfe --- /dev/null +++ b/libraries/LocalPeer/src/LockedFile.cpp @@ -0,0 +1,193 @@ +/**************************************************************************** +** +** 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" + +/*! + \class QtLockedFile + + \brief The QtLockedFile class extends QFile with advisory locking + functions. + + A file may be locked in read or write mode. Multiple instances of + \e QtLockedFile, created in multiple processes running on the same + machine, may have a file locked in read mode. Exactly one instance + may have it locked in write mode. A read and a write lock cannot + exist simultaneously on the same file. + + The file locks are advisory. This means that nothing prevents + another process from manipulating a locked file using QFile or + file system functions offered by the OS. Serialization is only + guaranteed if all processes that access the file use + QLockedFile. Also, while holding a lock on a file, a process + must not open the same file again (through any API), or locks + can be unexpectedly lost. + + The lock provided by an instance of \e QtLockedFile is released + whenever the program terminates. This is true even when the + program crashes and no destructors are called. +*/ + +/*! \enum QtLockedFile::LockMode + + This enum describes the available lock modes. + + \value ReadLock A read lock. + \value WriteLock A write lock. + \value NoLock Neither a read lock nor a write lock. +*/ + +/*! + Constructs an unlocked \e QtLockedFile object. This constructor + behaves in the same way as \e QFile::QFile(). + + \sa QFile::QFile() +*/ +LockedFile::LockedFile() + : QFile() +{ +#ifdef Q_OS_WIN + wmutex = 0; + rmutex = 0; +#endif + m_lock_mode = NoLock; +} + +/*! + Constructs an unlocked QtLockedFile object with file \a name. This + constructor behaves in the same way as \e QFile::QFile(const + QString&). + + \sa QFile::QFile() +*/ +LockedFile::LockedFile(const QString &name) + : QFile(name) +{ +#ifdef Q_OS_WIN + wmutex = 0; + rmutex = 0; +#endif + m_lock_mode = NoLock; +} + +/*! +Opens the file in OpenMode \a mode. + +This is identical to QFile::open(), with the one exception that the +Truncate mode flag is disallowed. Truncation would conflict with the +advisory file locking, since the file would be modified before the +write lock is obtained. If truncation is required, use resize(0) +after obtaining the write lock. + +Returns true if successful; otherwise false. + +\sa QFile::open(), QFile::resize() +*/ +bool LockedFile::open(OpenMode mode) +{ + if (mode & QIODevice::Truncate) { + qWarning("QtLockedFile::open(): Truncate mode not allowed."); + return false; + } + return QFile::open(mode); +} + +/*! + Returns \e true if this object has a in read or write lock; + otherwise returns \e false. + + \sa lockMode() +*/ +bool LockedFile::isLocked() const +{ + return m_lock_mode != NoLock; +} + +/*! + Returns the type of lock currently held by this object, or \e + QtLockedFile::NoLock. + + \sa isLocked() +*/ +LockedFile::LockMode LockedFile::lockMode() const +{ + return m_lock_mode; +} + +/*! + \fn bool QtLockedFile::lock(LockMode mode, bool block = true) + + Obtains a lock of type \a mode. The file must be opened before it + can be locked. + + If \a block is true, this function will block until the lock is + aquired. If \a block is false, this function returns \e false + immediately if the lock cannot be aquired. + + If this object already has a lock of type \a mode, this function + returns \e true immediately. If this object has a lock of a + different type than \a mode, the lock is first released and then a + new lock is obtained. + + This function returns \e true if, after it executes, the file is + locked by this object, and \e false otherwise. + + \sa unlock(), isLocked(), lockMode() +*/ + +/*! + \fn bool QtLockedFile::unlock() + + Releases a lock. + + If the object has no lock, this function returns immediately. + + This function returns \e true if, after it executes, the file is + not locked by this object, and \e false otherwise. + + \sa lock(), isLocked(), lockMode() +*/ + +/*! + \fn QtLockedFile::~QtLockedFile() + + Destroys the \e QtLockedFile object. If any locks were held, they + are released. +*/ -- cgit v1.2.3