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/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Qt Software Information (qt-info@nokia.com)
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the either Technology Preview License Agreement or the
** Beta Release License Agreement.
**
** 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 1.0, 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.
**
** If you are unsure which license is appropriate for your use, please
** contact the sales department at qt-sales@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#include "qhistorystate.h"
#ifndef QT_NO_STATEMACHINE
#include "qhistorystate_p.h"
QT_BEGIN_NAMESPACE
/*!
\class QHistoryState
\brief The QHistoryState class provides a means of returning to a previously active substate.
\since 4.6
\ingroup statemachine
A history state is a pseudo-state that represents the child state that the
parent state was in the last time the parent state was exited. A transition
with a history state as its target is in fact a transition to one of the
other child states of the parent state. QHistoryState is part of \l{The
State Machine Framework}.
Use the setDefaultState() function to set the state that should be entered
if the parent state has never been entered. Example:
\code
QStateMachine machine;
QState *s1 = new QState();
QState *s11 = new QState(s1);
QState *s12 = new QState(s1);
QHistoryState *s1h = new QHistoryState(s1);
s1h->setDefaultState(s11);
machine.addState(s1);
QState *s2 = new QState();
machine.addState(s2);
QPushButton *button = new QPushButton();
// Clicking the button will cause the state machine to enter the child state
// that s1 was in the last time s1 was exited, or the history state's default
// state if s1 has never been entered.
s1->addTransition(button, SIGNAL(clicked()), s1h);
\endcode
By default a history state is shallow, meaning that it won't remember nested
states. This can be configured through the historyType property.
*/
/*!
\property QHistoryState::defaultState
\brief the default state of this history state
*/
/*!
\property QHistoryState::historyType
\brief the type of history that this history state records
The default value of this property is QHistoryState::ShallowHistory.
*/
/*!
\enum QHistoryState::HistoryType
This enum specifies the type of history that a QHistoryState records.
\value ShallowHistory Only the immediate child states of the parent state
are recorded. In this case a transition with the history state as its
target will end up in the immediate child state that the parent was in the
last time it was exited. This is the default.
\value DeepHistory Nested states are recorded. In this case a transition
with the history state as its target will end up in the most deeply nested
descendant state the parent was in the last time it was exited.
*/
QHistoryStatePrivate::QHistoryStatePrivate()
: defaultState(0)
{
}
QHistoryStatePrivate *QHistoryStatePrivate::get(QHistoryState *q)
{
return q->d_func();
}
/*!
Constructs a new shallow history state with the given \a parent state.
*/
QHistoryState::QHistoryState(QState *parent)
: QAbstractState(*new QHistoryStatePrivate, parent)
{
Q_D(QHistoryState);
d->historyType = ShallowHistory;
}
/*!
Constructs a new history state of the given \a type, with the given \a
parent state.
*/
QHistoryState::QHistoryState(HistoryType type, QState *parent)
: QAbstractState(*new QHistoryStatePrivate, parent)
{
Q_D(QHistoryState);
d->historyType = type;
}
/*!
Destroys this history state.
*/
QHistoryState::~QHistoryState()
{
}
/*!
Returns this history state's default state. The default state indicates the
state to transition to if the parent state has never been entered before.
*/
QAbstractState *QHistoryState::defaultState() const
{
Q_D(const QHistoryState);
return d->defaultState;
}
/*!
Sets this history state's default state to be the given \a state.
\a state must be a sibling of this history state.
*/
void QHistoryState::setDefaultState(QAbstractState *state)
{
Q_D(QHistoryState);
if (state && state->parentState() != parentState()) {
qWarning("QHistoryState::setDefaultState: state %p does not belong "
"to this history state's group (%p)", state, parentState());
return;
}
d->defaultState = state;
}
/*!
Returns the type of history that this history state records.
*/
QHistoryState::HistoryType QHistoryState::historyType() const
{
Q_D(const QHistoryState);
return d->historyType;
}
/*!
Sets the \a type of history that this history state records.
*/
void QHistoryState::setHistoryType(HistoryType type)
{
Q_D(QHistoryState);
d->historyType = type;
}
/*!
\reimp
*/
void QHistoryState::onEntry(QEvent *event)
{
Q_UNUSED(event);
}
/*!
\reimp
*/
void QHistoryState::onExit(QEvent *event)
{
Q_UNUSED(event);
}
/*!
\reimp
*/
bool QHistoryState::event(QEvent *e)
{
return QAbstractState::event(e);
}
QT_END_NAMESPACE
#endif //QT_NO_STATEMACHINE
|
