TimeoutTransition.cc

Go to the documentation of this file.

#include "TimeoutTransition.h"
 
#include <QtStateMachine/QState>
#include <QtStateMachine/QStateMachine>
 
TimeoutTransition::TimeoutTransition(int timeoutMsecs, QAbstractState* target)
    : QGCSignalTransition(this, &TimeoutTransition::timeout)
    , _timeoutMsecs(timeoutMsecs)
{
    if (target) {
        setTargetState(target);
    }
 
    _timer.setSingleShot(true);
    connect(&_timer, &QTimer::timeout, this, &TimeoutTransition::timeout);
}
 
void TimeoutTransition::attachToSourceState(QState* source)
{
    if (!source || _sourceAttached) {
        return;
    }
 
    connect(source, &QState::entered, this, &TimeoutTransition::_onSourceStateEntered, Qt::UniqueConnection);
    connect(source, &QState::exited, this, &TimeoutTransition::_onSourceStateExited, Qt::UniqueConnection);
    _sourceAttached = true;
}
 
void TimeoutTransition::_onAddedToState()
{
    // Connect to source state's entered/exited signals for timer control
    attachToSourceState(qobject_cast<QState*>(sourceState()));
}
 
void TimeoutTransition::_onSourceStateEntered()
{
    _timer.start(_timeoutMsecs);
}
 
void TimeoutTransition::_onSourceStateExited()
{
    _timer.stop();
}
 
bool TimeoutTransition::event(QEvent* e)
{
    // Detect when transition is added to a state (parent changes)
    if (e->type() == QEvent::ParentChange) {
        _onAddedToState();
 
        // In some addTransition paths sourceState() is not finalized yet during
        // the immediate ParentChange callback. Retry once on the next turn.
        if (!_sourceAttached) {
            QTimer::singleShot(0, this, [this]() { _onAddedToState(); });
        }
    }
    return QGCSignalTransition::event(e);
}
 
void TimeoutTransition::onTransition(QEvent* event)
{
    Q_UNUSED(event);
    // Timer already stopped by _onSourceStateExited or will be stopped when we leave
}