path: root/src/corelib/statemachine/qeventtransition.cpp

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#include "qeventtransition.h"
#include "qeventtransition_p.h"
#include "qboundevent_p.h"
#include "qstate.h"
#include "qstate_p.h"
#include "qstatemachine.h"
#include "qstatemachine_p.h"
#include <qdebug.h>

QT_BEGIN_NAMESPACE

/*!
  \class QEventTransition

  \brief The QEventTransition class provides a QObject-specific transition for Qt events.

  \since 4.6
  \ingroup statemachine

  A QEventTransition object binds an event to a particular QObject.
  QEventTransition is part of \l{The State Machine Framework}.

  Example:

  \code
  QPushButton *button = ...;
  QState *s1 = ...;
  QState *s2 = ...;
  // If in s1 and the button receives an Enter event, transition to s2
  QEventTransition *enterTransition = new QEventTransition(button, QEvent::Enter);
  enterTransition->setTargetState(s2);
  s1->addTransition(enterTransition);
  // If in s2 and the button receives an Exit event, transition back to s1
  QEventTransition *leaveTransition = new QEventTransition(button, QEvent::Leave);
  leaveTransition->setTargetState(s1);
  s2->addTransition(leaveTransition);
  \endcode

  \section1 Subclassing

  Many event classes have attributes in addition to the event type itself.
  The testEventCondition() function can be reimplemented to check attributes
  of an event instance in order to determine whether the transition should be
  triggered or not.

  \sa QState::addTransition()
*/

/*!
    \property QEventTransition::eventObject

    \brief the event source that this event transition is associated with
*/

/*!
    \property QEventTransition::eventType

    \brief the type of event that this event transition is associated with
*/
QEventTransitionPrivate::QEventTransitionPrivate()
{
    object = 0;
    eventType = QEvent::None;
    registered = false;
}

QEventTransitionPrivate *QEventTransitionPrivate::get(QEventTransition *q)
{
    return q->d_func();
}

void QEventTransitionPrivate::invalidate()
{
    Q_Q(QEventTransition);
    if (registered) {
        QState *source = sourceState();
        QStatePrivate *source_d = QStatePrivate::get(source);
        QStateMachinePrivate *mach = QStateMachinePrivate::get(source_d->machine());
        if (mach) {
            mach->unregisterEventTransition(q);
            if (mach->configuration.contains(source))
                mach->registerEventTransition(q);
        }
    }
}

/*!
  Constructs a new QEventTransition object with the given \a sourceState.
*/
QEventTransition::QEventTransition(QState *sourceState)
    : QAbstractTransition(*new QEventTransitionPrivate, sourceState)
{
}

/*!
  Constructs a new QEventTransition object associated with events of the given
  \a type for the given \a object, and with the given \a sourceState.
*/
QEventTransition::QEventTransition(QObject *object, QEvent::Type type,
                                   QState *sourceState)
    : QAbstractTransition(*new QEventTransitionPrivate, sourceState)
{
    Q_D(QEventTransition);
    d->registered = false;
    d->object = object;
    d->eventType = type;
}

/*!
  Constructs a new QEventTransition object associated with events of the given
  \a type for the given \a object. The transition has the given \a targets and
  \a sourceState.
*/
QEventTransition::QEventTransition(QObject *object, QEvent::Type type,
                                   const QList<QAbstractState*> &targets,
                                   QState *sourceState)
    : QAbstractTransition(*new QEventTransitionPrivate, targets, sourceState)
{
    Q_D(QEventTransition);
    d->registered = false;
    d->object = object;
    d->eventType = type;
}

/*!
  \internal
*/
QEventTransition::QEventTransition(QEventTransitionPrivate &dd, QState *parent)
    : QAbstractTransition(dd, parent)
{
}

/*!
  \internal
*/
QEventTransition::QEventTransition(QEventTransitionPrivate &dd, QObject *object,
                                   QEvent::Type type, QState *parent)
    : QAbstractTransition(dd, parent)
{
    Q_D(QEventTransition);
    d->registered = false;
    d->object = object;
    d->eventType = type;
}

/*!
  \internal
*/
QEventTransition::QEventTransition(QEventTransitionPrivate &dd, QObject *object,
                                   QEvent::Type type, const QList<QAbstractState*> &targets,
                                   QState *parent)
    : QAbstractTransition(dd, targets, parent)
{
    Q_D(QEventTransition);
    d->registered = false;
    d->object = object;
    d->eventType = type;
}

/*!
  Destroys this QObject event transition.
*/
QEventTransition::~QEventTransition()
{
}

/*!
  Returns the event type that this event transition is associated with.
*/
QEvent::Type QEventTransition::eventType() const
{
    Q_D(const QEventTransition);
    return d->eventType;
}

/*!
  Sets the event \a type that this event transition is associated with.
*/
void QEventTransition::setEventType(QEvent::Type type)
{
    Q_D(QEventTransition);
    if (d->eventType == type)
        return;
    d->eventType = type;
    d->invalidate();
}

/*!
  Returns the event source associated with this event transition.
*/
QObject *QEventTransition::eventObject() const
{
    Q_D(const QEventTransition);
    return d->object;
}

/*!
  Sets the event source associated with this event transition to be the given
  \a object.
*/
void QEventTransition::setEventObject(QObject *object)
{
    Q_D(QEventTransition);
    if (d->object == object)
        return;
    d->object = object;
    d->invalidate();
}

/*!
  \reimp
*/
bool QEventTransition::eventTest(QEvent *event) const
{
    Q_D(const QEventTransition);
#ifdef QT_STATEMACHINE_SOLUTION
    if (event->type() == QEvent::Type(QEvent::User-3)) {
#else
    if (event->type() == QEvent::Bound) {
#endif
        QBoundEvent *oe = static_cast<QBoundEvent*>(event);
        return (oe->object() == d->object)
            && (oe->event()->type() == d->eventType)
            && testEventCondition(oe->event());
    }
    return false;
}

/*!
  \reimp
*/
void QEventTransition::onTransition()
{
}

/*!
  Tests an instance of an event associated with this event transition and
  returns true if the transition should be taken, otherwise returns false.
  The type of the given \a event will be eventType().

  Reimplement this function if you have custom conditions associated with
  the transition. The default implementation always returns true.
*/
bool QEventTransition::testEventCondition(QEvent *event) const
{
    Q_UNUSED(event);
    return true;
}

/*!
  \reimp
*/
bool QEventTransition::event(QEvent *e)
{
    return QAbstractTransition::event(e);
}

QT_END_NAMESPACE