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| /****************************************************************************
**
** Copyright (C) 2010 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.
**
** 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 Nokia Corporation 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."
**
****************************************************************************/
#include "qtsingleapplication.h"
#include "qtlocalpeer.h"
#include <QtGui>
#include <QWidget>
/*!
\class QtSingleApplication qtsingleapplication.h
\brief The QtSingleApplication class provides an API to detect and
communicate with running instances of an application.
This class allows you to create applications where only one
instance should be running at a time. I.e., if the user tries to
launch another instance, the already running instance will be
activated instead. Another usecase is a client-server system,
where the first started instance will assume the role of server,
and the later instances will act as clients of that server.
By default, the full path of the executable file is used to
determine whether two processes are instances of the same
application. You can also provide an explicit identifier string
that will be compared instead.
The application should create the QtSingleApplication object early
in the startup phase, and call isRunning() to find out if another
instance of this application is already running. If isRunning()
returns false, it means that no other instance is running, and
this instance has assumed the role as the running instance. In
this case, the application should continue with the initialization
of the application user interface before entering the event loop
with exec(), as normal.
The messageReceived() signal will be emitted when the running
application receives messages from another instance of the same
application. When a message is received it might be helpful to the
user to raise the application so that it becomes visible. To
facilitate this, QtSingleApplication provides the
setActivationWindow() function and the activateWindow() slot.
If isRunning() returns true, another instance is already
running. It may be alerted to the fact that another instance has
started by using the sendMessage() function. Also data such as
startup parameters (e.g. the name of the file the user wanted this
new instance to open) can be passed to the running instance with
this function. Then, the application should terminate (or enter
client mode).
If isRunning() returns true, but sendMessage() fails, that is an
indication that the running instance is frozen.
Here's an example that shows how to convert an existing
application to use QtSingleApplication. It is very simple and does
not make use of all QtSingleApplication's functionality (see the
examples for that).
\code
// Original
int main(int argc, char **argv)
{
QApplication app(argc, argv);
MyMainWidget mmw;
mmw.show();
return app.exec();
}
// Single instance
int main(int argc, char **argv)
{
QtSingleApplication app(argc, argv);
if (app.isRunning())
return !app.sendMessage(someDataString);
MyMainWidget mmw;
app.setActivationWindow(&mmw);
mmw.show();
return app.exec();
}
\endcode
Once this QtSingleApplication instance is destroyed (normally when
the process exits or crashes), when the user next attempts to run the
application this instance will not, of course, be encountered. The
next instance to call isRunning() or sendMessage() will assume the
role as the new running instance.
For console (non-GUI) applications, QtSingleCoreApplication may be
used instead of this class, to avoid the dependency on the QtGui
library.
\sa QtSingleCoreApplication
*/
void QtSingleApplication::sysInit(const QString &appId)
{
actWin = 0;
peer = new QtLocalPeer(this, appId);
connect(peer, SIGNAL(messageReceived(const QString&)), SIGNAL(messageReceived(const QString&)));
}
/*!
Creates a QtSingleApplication object. The application identifier
will be QCoreApplication::applicationFilePath(). \a argc, \a
argv, and \a GUIenabled are passed on to the QAppliation constructor.
If you are creating a console application (i.e. setting \a
GUIenabled to false), you may consider using
QtSingleCoreApplication instead.
*/
QtSingleApplication::QtSingleApplication(int &argc, char **argv, bool GUIenabled)
: QApplication(argc, argv, GUIenabled)
{
sysInit();
}
/*!
Creates a QtSingleApplication object with the application
identifier \a appId. \a argc and \a argv are passed on to the
QAppliation constructor.
*/
QtSingleApplication::QtSingleApplication(const QString &appId, int &argc, char **argv)
: QApplication(argc, argv)
{
sysInit(appId);
}
/*!
Creates a QtSingleApplication object. The application identifier
will be QCoreApplication::applicationFilePath(). \a argc, \a
argv, and \a type are passed on to the QAppliation constructor.
*/
QtSingleApplication::QtSingleApplication(int &argc, char **argv, Type type)
: QApplication(argc, argv, type)
{
sysInit();
}
#if defined(Q_WS_X11)
/*!
Special constructor for X11, ref. the documentation of
QApplication's corresponding constructor. The application identifier
will be QCoreApplication::applicationFilePath(). \a dpy, \a visual,
and \a cmap are passed on to the QApplication constructor.
*/
QtSingleApplication::QtSingleApplication(Display* dpy, Qt::HANDLE visual, Qt::HANDLE cmap)
: QApplication(dpy, visual, cmap)
{
sysInit();
}
/*!
Special constructor for X11, ref. the documentation of
QApplication's corresponding constructor. The application identifier
will be QCoreApplication::applicationFilePath(). \a dpy, \a argc, \a
argv, \a visual, and \a cmap are passed on to the QApplication
constructor.
*/
QtSingleApplication::QtSingleApplication(Display *dpy, int &argc, char **argv, Qt::HANDLE visual, Qt::HANDLE cmap)
: QApplication(dpy, argc, argv, visual, cmap)
{
sysInit();
}
/*!
Special constructor for X11, ref. the documentation of
QApplication's corresponding constructor. The application identifier
will be \a appId. \a dpy, \a argc, \a
argv, \a visual, and \a cmap are passed on to the QApplication
constructor.
*/
QtSingleApplication::QtSingleApplication(Display* dpy, const QString &appId, int argc, char **argv, Qt::HANDLE visual, Qt::HANDLE cmap)
: QApplication(dpy, argc, argv, visual, cmap)
{
sysInit(appId);
}
#endif
/*!
Returns true if another instance of this application is running;
otherwise false.
This function does not find instances of this application that are
being run by a different user (on Windows: that are running in
another session).
\sa sendMessage()
*/
bool QtSingleApplication::isRunning()
{
return peer->isClient();
}
/*!
Tries to send the text \a message to the currently running
instance. The QtSingleApplication object in the running instance
will emit the messageReceived() signal when it receives the
message.
This function returns true if the message has been sent to, and
processed by, the current instance. If there is no instance
currently running, or if the running instance fails to process the
message within \a timeout milliseconds, this function return false.
\sa isRunning(), messageReceived()
*/
bool QtSingleApplication::sendMessage(const QString &message, int timeout)
{
return peer->sendMessage(message, timeout);
}
/*!
Returns the application identifier. Two processes with the same
identifier will be regarded as instances of the same application.
*/
QString QtSingleApplication::id() const
{
return peer->applicationId();
}
/*!
Sets the activation window of this application to \a aw. The
activation window is the widget that will be activated by
activateWindow(). This is typically the application's main window.
If \a activateOnMessage is true (the default), the window will be
activated automatically every time a message is received, just prior
to the messageReceived() signal being emitted.
\sa activateWindow(), messageReceived()
*/
void QtSingleApplication::setActivationWindow(QWidget* aw, bool activateOnMessage)
{
actWin = aw;
if (activateOnMessage)
connect(peer, SIGNAL(messageReceived(const QString&)), this, SLOT(activateWindow()));
else
disconnect(peer, SIGNAL(messageReceived(const QString&)), this, SLOT(activateWindow()));
}
/*!
Returns the applications activation window if one has been set by
calling setActivationWindow(), otherwise returns 0.
\sa setActivationWindow()
*/
QWidget* QtSingleApplication::activationWindow() const
{
return actWin;
}
/*!
De-minimizes, raises, and activates this application's activation window.
This function does nothing if no activation window has been set.
This is a convenience function to show the user that this
application instance has been activated when he has tried to start
another instance.
This function should typically be called in response to the
messageReceived() signal. By default, that will happen
automatically, if an activation window has been set.
\sa setActivationWindow(), messageReceived(), initialize()
*/
void QtSingleApplication::activateWindow()
{
if (actWin) {
actWin->setWindowState(actWin->windowState() & ~Qt::WindowMinimized);
actWin->raise();
actWin->activateWindow();
}
}
/*!
\fn void QtSingleApplication::messageReceived(const QString& message)
This signal is emitted when the current instance receives a \a
message from another instance of this application.
\sa sendMessage(), setActivationWindow(), activateWindow()
*/
/*!
\fn void QtSingleApplication::initialize(bool dummy = true)
\obsolete
*/ |
