The QSessionManager class provides access to the session manager. More...

Inheritance diagram for QSessionManager:

Public Types
enum	RestartHint

Public Methods
bool	allowsErrorInteraction ()

bool	allowsInteraction ()

void	cancel ()

QStringList	discardCommand () const

bool	isPhase2 () const

void	release ()

void	requestPhase2 ()

QStringList	restartCommand () const

RestartHint	restartHint () const

QString	sessionId () const

QString	sessionKey () const

void	setDiscardCommand (const QStringList &list)

void	setManagerProperty (const QString &name, const QString &value)

void	setManagerProperty (const QString &name, const QStringList &value)

void	setRestartCommand (const QStringList &list)

void	setRestartHint (RestartHint hint)

Public Methods inherited from QObject
	QObject (QObject *parent=nullptr)

	~QObject ()

bool	blockSignals (bool block)

const QList< QObject * > &	children () const

bool	connect (const QObject *sender, const QString &signalMethod, const QString &location, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

bool	connect (const QObject *sender, const QString &signalMethod, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

bool	disconnect (const QObject *receiver, const QString &slotMethod=QString ()) const

bool	disconnect (const QString &signalMethod, const QString &location, const QObject *receiver=nullptr, const QString &slotMethod=QString ()) const

bool	disconnect (const QString &signalMethod=QString (), const QObject *receiver=nullptr, const QString &slotMethod=QString ()) const

void	dumpObjectInfo ()

void	dumpObjectTree ()

QList< QString >	dynamicPropertyNames () const

virtual bool	event (QEvent *event)

virtual bool	eventFilter (QObject watched, QEvent event)

template<typename T >
T	findChild (const QString &childName=QString ()) const

template<class T >
QList< T >	findChildren (const QRegularExpression &regExp, Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

template<class T >
QList< T >	findChildren (const QString &childName=QString (), Qt::FindChildOptions options=Qt::FindChildrenRecursively) const

bool	inherits (const QString &className) const

void	installEventFilter (QObject *filterObj)

bool	isWidgetType () const

bool	isWindowType () const

void	killTimer (int id)

const QMetaObject *	metaObject () const

void	moveToThread (QThread *targetThread)

QString	objectName () const

QObject *	parent () const

template<class T = QVariant>
T	property (const QString &name) const

void	removeEventFilter (QObject *obj)

void	setObjectName (const QString &name)

void	setParent (QObject *parent)

bool	setProperty (const QString &name, const QVariant &value)

bool	signalsBlocked () const

int	startTimer (int interval, Qt::TimerType timerType=Qt::CoarseTimer)

QThread *	thread () const

Friends
class	QApplication

Additional Inherited Members
Public Signals inherited from QObject
void	destroyed (QObject *obj=nullptr)

void	objectNameChanged (const QString &objectName)

Public Slots inherited from QObject
void	deleteLater ()

Static Public Methods inherited from QObject
static bool	connect (const QObject sender, const QMetaMethod &signalMethod, const QObject receiver, const QMetaMethod &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

static bool	connect (const QObject sender, const QString &signalMethod, const QObject receiver, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection, const QString &location=QString ())

static bool	connect (const QObject sender, const QString &signalMethod, const QString &location, const QObject receiver, const QString &slotMethod, Qt::ConnectionType type=Qt::AutoConnection)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class SlotClass , class... SlotArgs, class SlotReturn >
static bool	connect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver receiver, SlotReturn (SlotClass::slotMethod)(SlotArgs...), Qt::ConnectionType type=Qt::AutoConnection)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class T >
static bool	connect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver *receiver, T slotLambda, Qt::ConnectionType type=Qt::AutoConnection)

static bool	disconnect (const QObject sender, const QMetaMethod &signalMethod, const QObject receiver, const QMetaMethod &slotMethod)

static bool	disconnect (const QObject sender, const QString &signalMethod, const QObject receiver, const QString &slotMethod)

static bool	disconnect (const QObject sender, const QString &signalMethod, const QString &location, const QObject receiver, const QString &slotMethod)

static bool	disconnect (const QObject sender, std::nullptr_t, const QObject receiver, std::nullptr_t)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class SlotClass , class... SlotArgs, class SlotReturn >
static bool	disconnect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver receiver, SlotReturn (SlotClass::slotMethod)(SlotArgs...))

template<class Sender , class SignalClass , class... SignalArgs, class Receiver >
static bool	disconnect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver *receiver, std::nullptr_t slotMethod=nullptr)

template<class Sender , class SignalClass , class... SignalArgs, class Receiver , class T >
static bool	disconnect (const Sender sender, void (SignalClass::signalMethod)(SignalArgs...), const Receiver *receiver, T slotMethod)

static QMetaObject &	staticMetaObject ()

static QString	tr (const char text, const char comment=nullptr, std::optional< int > numArg=std::optional< int >())

Protected Methods inherited from QObject
virtual void	childEvent (QChildEvent *event)

virtual void	connectNotify (const QMetaMethod &signalMethod) const

virtual void	customEvent (QEvent *event)

virtual void	disconnectNotify (const QMetaMethod &signalMethod) const

bool	isSignalConnected (const QMetaMethod &signalMethod) const

int	receivers (const QString &signal) const

QObject *	sender () const

int	senderSignalIndex () const

virtual void	timerEvent (QTimerEvent *event)

Properties inherited from QObject
	objectName

Related Functions inherited from QObject
T	qobject_cast (QObject *object)

	QObjectList

Detailed Description

The QSessionManager class provides access to the session manager.

A session manager in a desktop environment (in which CopperSpice GUI applications live) keeps track of a session, which is a group of running applications, each of which has a particular state. The state of an application contains (most notably) the documents the application has open and the position and size of its windows.

The session manager is used to save the session, e.g., when the machine is shut down, and to restore a session, e.g., when the machine is started up. We recommend that you use QSettings to save an application's settings, for example, window positions, recently used files, etc. When the application is restarted by the session manager, you can restore the settings.

QSessionManager provides an interface between the application and the session manager so that the program can work well with the session manager. Session management requests for action are handled by the two virtual functions QApplication::commitData() and QApplication::saveState(). Both provide a reference to a session manager object as argument, to allow the application to communicate with the session manager. The session manager can only be accessed through these functions.

No user interaction is possible unless the application gets explicit permission from the session manager. You ask for permission by calling allowsInteraction() or, if it is really urgent, allowsErrorInteraction(). CopperSpice does not enforce this, but the session manager may.

You can try to abort the shutdown process by calling cancel(). The default commitData() function does this if some top-level window rejected its closeEvent().

For sophisticated session managers provided on Unix/X11, QSessionManager offers further possibilities to fine-tune an application's session management behavior: setRestartCommand(), setDiscardCommand(), setRestartHint(), setProperty(), requestPhase2(). See the respective function descriptions for further details.

See also: QApplication, Session Management

Member Enumeration Documentation

enum QSessionManager::RestartHint

This enum type defines the circumstances under which this application wants to be restarted by the session manager. The current values are:

Constant	Value	Description
`QSessionManager::RestartIfRunning`	`0`	If the application is still running when the session is shut down, it wants to be restarted at the start of the next session.
`QSessionManager::RestartAnyway`	`1`	The application wants to be started at the start of the next session, no matter what. (This is useful for utilities that run just after startup and then quit.)
`QSessionManager::RestartImmediately`	`2`	The application wants to be started immediately whenever it is not running.
`QSessionManager::RestartNever`	`3`	The application does not want to be restarted automatically.

The default hint is RestartIfRunning.

Method Documentation

bool QSessionManager::allowsErrorInteraction ( )

Returns true if error interaction is permitted, otherwise returns false.

This is similar to allowsInteraction(), but also enables the application to tell the user about any errors that occur. Session managers may give error interaction requests higher priority, which means that it is more likely that an error interaction is permitted. However, you are still not guaranteed that the session manager will allow interaction.

See also: allowsInteraction(), release(), cancel()

bool QSessionManager::allowsInteraction ( )

Asks the session manager for permission to interact with the user. Returns true if interaction is permitted, otherwise returns false.

The rationale behind this mechanism is to make it possible to synchronize user interaction during a shutdown. Advanced session managers may ask all applications simultaneously to commit their data, resulting in a much faster shutdown.

When the interaction is completed we strongly recommend releasing the user interaction semaphore with a call to release(). This way, other applications may get the chance to interact with the user while your application is still busy saving data. (The semaphore is implicitly released when the application exits.)

If the user decides to cancel the shutdown process during the interaction phase, you must tell the session manager that this has happened by calling cancel().

Here is an example of how an application's QApplication::commitData() might be implemented:

void MyApplication::commitData(QSessionManager& manager)
{
    if (manager.allowsInteraction()) {
        int retval = QMessageBox::warning(mainWindow, tr("My Application"),
              tr("Save changes to document?"), QMessageBox::Save | QMessageBox::Discard | QMessageBox::Cancel);
 
        switch (retval) {
           case QMessageBox::Save:
               manager.release();
               if (!saveDocument())
                   manager.cancel();
               break;
 
           case QMessageBox::Discard:
               break;
 
           case QMessageBox::Cancel:
           default:
               manager.cancel();
        }
 
    } else {
        // interaction not allowed, select some default behavior
    }
}

If an error occurred within the application while saving its data, you may want to try allowsErrorInteraction() instead.

See also: QApplication::commitDataRequest(), release(), cancel()

void QSessionManager::cancel ( )

Tells the session manager to cancel the shutdown process. Applications should not call this function without asking the user first.

See also: allowsInteraction(), allowsErrorInteraction()

QStringList QSessionManager::discardCommand ( ) const

Returns the currently set discard command. To navigate through a list you can use a range based for loop.

for (const QString &command : mySession.discardCommand()) {
   do_something(command);
}

See also: setDiscardCommand(), restartCommand(), setRestartCommand()

bool QSessionManager::isPhase2 ( ) const

Returns true if the session manager is currently performing a second session management phase, otherwise returns false.

See also: requestPhase2()

void QSessionManager::release ( )

Releases the session manager's interaction semaphore after an interaction phase.

See also: allowsInteraction(), allowsErrorInteraction()

void QSessionManager::requestPhase2 ( )

Requests a second session management phase for the application. The application may then return immediately from the QApplication::commitData() or QApplication::saveState() function, and they will be called again once most or all other applications have finished their session management.

The two phases are useful for applications such as the X11 window manager that need to store information about another application's windows and therefore have to wait until these applications have completed their respective session management tasks.

Note: If another application has requested a second phase it may get called before, simultaneously with, or after your application's second phase.

See also: isPhase2()

QStringList QSessionManager::restartCommand ( ) const

Returns the currently set restart command. To navigate through a list you can use a range based for loop.

for (const QString &command : mySession.restartCommand()) {
   do_something(command);
}

See also: setRestartCommand(), restartHint()

RestartHint QSessionManager::restartHint ( ) const

Returns the application's current restart hint. The default is RestartIfRunning.

See also: setRestartHint()

QString QSessionManager::sessionId ( ) const

Returns the identifier of the current session. If the application has been restored from an earlier session, this identifier is the same as it was in the earlier session.

See also: sessionKey(), QApplication::sessionId()

QString QSessionManager::sessionKey ( ) const

Returns the session key in the current session. If the application has been restored from an earlier session, this key is the same as it was when the previous session ended. The session key changes with every call of commitData() or saveState().

See also: sessionId(), QApplication::sessionKey()

void QSessionManager::setDiscardCommand ( const QStringList & list )

Sets the discard command to the given list.

See also: discardCommand(), setRestartCommand()

void QSessionManager::setManagerProperty	(	const QString &	name,
		const QString &	value
	)

Low-level write access to the application's identification and state records are kept in the session manager. The property called name has its value set to the string value.

void QSessionManager::setManagerProperty	(	const QString &	name,
		const QStringList &	value
	)

Low-level write access to the application's identification and state record are kept in the session manager. The property called name has its value set to the string list value.

void QSessionManager::setRestartCommand ( const QStringList & list )

If the session manager is capable of restoring sessions it will execute the command specified in list in order to restore the application. If this method is not called the default is equivalent to the code shown below.

appname -session id

The -session option is mandatory, otherwise QApplication can not tell whether it has been restored or what the current session identifier is. Refer QApplication::isSessionRestored() and QApplication::sessionId() for details.

If your application is very simple, it may be possible to store the entire application state in additional command line options. This is usually a very bad idea because command lines are often limited to a few hundred bytes. Instead, use QSettings, temporary files, or a database for this purpose. By marking the data with the unique sessionId(), you will be able to restore the application in a future session.

See also: restartCommand(), setDiscardCommand(), setRestartHint()

void QSessionManager::setRestartHint ( RestartHint hint )

Sets the application's restart hint to hint. On application startup, the hint is set to RestartIfRunning. This method should be called from QApplication::saveState() because most session managers perform a checkpoint shortly after an application's startup.

Note: These flags are only hints, a session manager may or may not respect them.

See also: restartHint()

Public Types

Public Methods

Friends

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

Method Documentation