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

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#include "qsignaltransition.h"

#ifndef QT_NO_STATEMACHINE

#include "qsignaltransition_p.h"
#include "qstate.h"
#include "qstate_p.h"
#include "qstatemachine.h"
#include "qstatemachine_p.h"
#include <qdebug.h>

QT_BEGIN_NAMESPACE

/*!
  \class QSignalTransition

  \brief The QSignalTransition class provides a transition based on a Qt signal.

  \since 4.6
  \ingroup statemachine

  Typically you would use the overload of QState::addTransition() that takes a
  sender and signal as arguments, rather than creating QSignalTransition
  objects directly. QSignalTransition is part of \l{The State Machine
  Framework}.

  You can subclass QSignalTransition and reimplement eventTest() to make a
  signal transition conditional; the event object passed to eventTest() will
  be a QStateMachine::SignalEvent object. Example:

  \code
  class CheckedTransition : public QSignalTransition
  {
  public:
      CheckedTransition(QCheckBox *check)
          : QSignalTransition(check, SIGNAL(stateChanged(int))) {}
  protected:
      bool eventTest(QEvent *e) {
          if (!QSignalTransition::eventTest(e))
              return false;
          QStateMachine::SignalEvent *se = static_cast<QStateMachine::SignalEvent*>(e);
          return (se->arguments().at(0).toInt() == Qt::Checked);
      }
  };

  ...

  QCheckBox *check = new QCheckBox();
  check->setTristate(true);

  QState *s1 = new QState();
  QState *s2 = new QState();
  CheckedTransition *t1 = new CheckedTransition(check);
  t1->setTargetState(s2);
  s1->addTransition(t1);
  \endcode
*/

/*!
    \property QSignalTransition::senderObject

    \brief the sender object that this signal transition is associated with
*/

/*!
    \property QSignalTransition::signal

    \brief the signal that this signal transition is associated with
*/

QSignalTransitionPrivate::QSignalTransitionPrivate()
{
    sender = 0;
    signalIndex = -1;
}

QSignalTransitionPrivate *QSignalTransitionPrivate::get(QSignalTransition *q)
{
    return q->d_func();
}

void QSignalTransitionPrivate::unregister()
{
    Q_Q(QSignalTransition);
    if ((signalIndex == -1) || !machine())
        return;
    QStateMachinePrivate::get(machine())->unregisterSignalTransition(q);
}

void QSignalTransitionPrivate::maybeRegister()
{
    Q_Q(QSignalTransition);
    if (!machine() || !machine()->configuration().contains(sourceState()))
        return;
    QStateMachinePrivate::get(machine())->registerSignalTransition(q);
}

/*!
  Constructs a new signal transition with the given \a sourceState.
*/
QSignalTransition::QSignalTransition(QState *sourceState)
    : QAbstractTransition(*new QSignalTransitionPrivate, sourceState)
{
}

/*!
  Constructs a new signal transition associated with the given \a signal of
  the given \a sender, and with the given \a sourceState.
*/
QSignalTransition::QSignalTransition(QObject *sender, const char *signal,
                                     QState *sourceState)
    : QAbstractTransition(*new QSignalTransitionPrivate, sourceState)
{
    Q_D(QSignalTransition);
    d->sender = sender;
    d->signal = signal;
}

/*!
  Destroys this signal transition.
*/
QSignalTransition::~QSignalTransition()
{
}

/*!
  Returns the sender object associated with this signal transition.
*/
QObject *QSignalTransition::senderObject() const
{
    Q_D(const QSignalTransition);
    return d->sender;
}

/*!
  Sets the \a sender object associated with this signal transition.
*/
void QSignalTransition::setSenderObject(QObject *sender)
{
    Q_D(QSignalTransition);
    if (sender == d->sender)
        return;
    d->unregister();
    d->sender = sender;
    d->maybeRegister();
}

/*!
  Returns the signal associated with this signal transition.
*/
QByteArray QSignalTransition::signal() const
{
    Q_D(const QSignalTransition);
    return d->signal;
}

/*!
  Sets the \a signal associated with this signal transition.
*/
void QSignalTransition::setSignal(const QByteArray &signal)
{
    Q_D(QSignalTransition);
    if (signal == d->signal)
        return;
    d->unregister();
    d->signal = signal;
    d->maybeRegister();
}

/*!
  \reimp

  The default implementation returns true if the \a event is a
  QStateMachine::SignalEvent object and the event's sender and signal index
  match this transition, and returns false otherwise.
*/
bool QSignalTransition::eventTest(QEvent *event)
{
    Q_D(const QSignalTransition);
    if (event->type() == QEvent::StateMachineSignal) {
        if (d->signalIndex == -1)
            return false;
        QStateMachine::SignalEvent *se = static_cast<QStateMachine::SignalEvent*>(event);
        return (se->sender() == d->sender)
            && (se->signalIndex() == d->signalIndex);
    }
    return false;
}

/*!
  \reimp
*/
void QSignalTransition::onTransition(QEvent *event)
{
    Q_UNUSED(event);
}

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

void QSignalTransitionPrivate::callOnTransition(QEvent *e)
{
    Q_Q(QSignalTransition);

    if (e->type() == QEvent::StateMachineSignal) {
        QStateMachine::SignalEvent *se = static_cast<QStateMachine::SignalEvent *>(e);
        int savedSignalIndex = se->m_signalIndex;
        se->m_signalIndex = originalSignalIndex;
        q->onTransition(e);
        se->m_signalIndex = savedSignalIndex;
    } else {
        q->onTransition(e);
    }
}

QT_END_NAMESPACE

#endif //QT_NO_STATEMACHINE