qstatemachine.cpp

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#include "qstatemachine.h"

#ifndef QT_NO_STATEMACHINE

#include "qstate.h"
#include "qstate_p.h"
#include "qstatemachine_p.h"
#include "qabstracttransition.h"
#include "qabstracttransition_p.h"
#include "qsignaltransition.h"
#include "qsignaltransition_p.h"
#include "qsignaleventgenerator_p.h"
#include "qabstractstate.h"
#include "qabstractstate_p.h"
#include "qfinalstate.h"
#include "qhistorystate.h"
#include "qhistorystate_p.h"
#include "private/qobject_p.h"
#include "private/qthread_p.h"

#ifndef QT_NO_STATEMACHINE_EVENTFILTER
#include "qeventtransition.h"
#include "qeventtransition_p.h"
#endif

#ifndef QT_NO_ANIMATION
#include "qpropertyanimation.h"
#include "qanimationgroup.h"
#include <private/qvariantanimation_p.h>
#endif

#include <QtCore/qmetaobject.h>
#include <qdebug.h>

QT_BEGIN_NAMESPACE

#ifndef QT_NO_ANIMATION

#endif

// #define QSTATEMACHINE_DEBUG

QStateMachinePrivate::QStateMachinePrivate()
{
    isMachine = true;

    state = NotRunning;
    _startState = 0;
    processing = false;
    processingScheduled = false;
    stop = false;
    stopProcessingReason = EventQueueEmpty;
    error = QStateMachine::NoError;
    globalRestorePolicy = QStateMachine::DontRestoreProperties;
    signalEventGenerator = 0;
#ifndef QT_NO_ANIMATION
    animated = true;
#endif
}

QStateMachinePrivate::~QStateMachinePrivate()
{
    qDeleteAll(internalEventQueue);
    qDeleteAll(externalEventQueue);
}

QStateMachinePrivate *QStateMachinePrivate::get(QStateMachine *q)
{
    if (q)
        return q->d_func();
    return 0;
}

QState *QStateMachinePrivate::rootState() const
{
    return const_cast<QStateMachine*>(q_func());
}

static QEvent *cloneEvent(QEvent *e)
{
    switch (e->type()) {
    case QEvent::None:
        return new QEvent(*e);
    case QEvent::Timer:
        return new QTimerEvent(*static_cast<QTimerEvent*>(e));
    default:
        Q_ASSERT_X(false, "cloneEvent()", "not implemented");
        break;
    }
    return 0;
}

const QStateMachinePrivate::Handler qt_kernel_statemachine_handler = {
    cloneEvent
};

const QStateMachinePrivate::Handler *QStateMachinePrivate::handler = &qt_kernel_statemachine_handler;

Q_CORE_EXPORT const QStateMachinePrivate::Handler *qcoreStateMachineHandler()
{
    return &qt_kernel_statemachine_handler;
}

static int indexOfDescendant(QState *s, QAbstractState *desc)
{
    QList<QAbstractState*> childStates = QStatePrivate::get(s)->childStates();
    for (int i = 0; i < childStates.size(); ++i) {
        QAbstractState *c = childStates.at(i);
        if ((c == desc) || QStateMachinePrivate::isDescendantOf(desc, c)) {
            return i;
        }
    }
    return -1;
}

bool QStateMachinePrivate::stateEntryLessThan(QAbstractState *s1, QAbstractState *s2)
{
    if (s1->parent() == s2->parent()) {
        return s1->children().indexOf(s1)
            < s2->children().indexOf(s2);
    } else if (isDescendantOf(s1, s2)) {
        return false;
    } else if (isDescendantOf(s2, s1)) {
        return true;
    } else {
        Q_ASSERT(s1->machine() != 0);
        QStateMachinePrivate *mach = QStateMachinePrivate::get(s1->machine());
        QState *lca = mach->findLCA(QList<QAbstractState*>() << s1 << s2);
        Q_ASSERT(lca != 0);
        return (indexOfDescendant(lca, s1) < indexOfDescendant(lca, s2));
    }
}

bool QStateMachinePrivate::stateExitLessThan(QAbstractState *s1, QAbstractState *s2)
{
    if (s1->parent() == s2->parent()) {
        return s1->children().indexOf(s1)
            < s2->children().indexOf(s2);
    } else if (isDescendantOf(s1, s2)) {
        return true;
    } else if (isDescendantOf(s2, s1)) {
        return false;
    } else {
        Q_ASSERT(s1->machine() != 0);
        QStateMachinePrivate *mach = QStateMachinePrivate::get(s1->machine());
        QState *lca = mach->findLCA(QList<QAbstractState*>() << s1 << s2);
        Q_ASSERT(lca != 0);
        return (indexOfDescendant(lca, s1) < indexOfDescendant(lca, s2));
    }
}

QState *QStateMachinePrivate::findLCA(const QList<QAbstractState*> &states) const
{
    if (states.isEmpty())
        return 0;
    QList<QState*> ancestors = properAncestors(states.at(0), rootState()->parentState());
    for (int i = 0; i < ancestors.size(); ++i) {
        QState *anc = ancestors.at(i);
        bool ok = true;
        for (int j = states.size() - 1; (j > 0) && ok; --j) {
            const QAbstractState *s = states.at(j);
            if (!isDescendantOf(s, anc))
                ok = false;
        }
        if (ok)
            return anc;
    }
    return 0;
}

bool QStateMachinePrivate::isPreempted(const QAbstractState *s, const QSet<QAbstractTransition*> &transitions) const
{
    QSet<QAbstractTransition*>::const_iterator it;
    for (it = transitions.constBegin(); it != transitions.constEnd(); ++it) {
        QAbstractTransition *t = *it;
        QList<QAbstractState*> lst = t->targetStates();
        if (!lst.isEmpty()) {
            lst.prepend(t->sourceState());
            QAbstractState *lca = findLCA(lst);
            if (isDescendantOf(s, lca)) {
#ifdef QSTATEMACHINE_DEBUG
                qDebug() << q_func() << ':' << transitions << "preempts selection of a transition from"
                         << s << "because" << s << "is a descendant of" << lca;
#endif
                return true;
            }
        }
    }
    return false;
}

QSet<QAbstractTransition*> QStateMachinePrivate::selectTransitions(QEvent *event) const
{
    Q_Q(const QStateMachine);
    QSet<QAbstractTransition*> enabledTransitions;
    QSet<QAbstractState*>::const_iterator it;
    const_cast<QStateMachine*>(q)->beginSelectTransitions(event);
    for (it = configuration.constBegin(); it != configuration.constEnd(); ++it) {
        QAbstractState *state = *it;
        if (!isAtomic(state))
            continue;
        if (isPreempted(state, enabledTransitions))
            continue;
        QList<QState*> lst = properAncestors(state, rootState()->parentState());
        if (QState *grp = toStandardState(state))
            lst.prepend(grp);
        bool found = false;
        for (int j = 0; (j < lst.size()) && !found; ++j) {
            QState *s = lst.at(j);
            QList<QAbstractTransition*> transitions = QStatePrivate::get(s)->transitions();
            for (int k = 0; k < transitions.size(); ++k) {
                QAbstractTransition *t = transitions.at(k);
                if (QAbstractTransitionPrivate::get(t)->callEventTest(event)) {
#ifdef QSTATEMACHINE_DEBUG
                    qDebug() << q << ": selecting transition" << t;
#endif
                    enabledTransitions.insert(t);
                    found = true;
                    break;
                }
            }
        }
    }
    const_cast<QStateMachine*>(q)->endSelectTransitions(event);
    return enabledTransitions;
}

void QStateMachinePrivate::microstep(QEvent *event, const QList<QAbstractTransition*> &enabledTransitions)
{
#ifdef QSTATEMACHINE_DEBUG
    qDebug() << q_func() << ": begin microstep( enabledTransitions:" << enabledTransitions << ')';
    qDebug() << q_func() << ": configuration before exiting states:" << configuration;
#endif
    QList<QAbstractState*> exitedStates = exitStates(event, enabledTransitions);
#ifdef QSTATEMACHINE_DEBUG
    qDebug() << q_func() << ": configuration after exiting states:" << configuration;
#endif
    executeTransitionContent(event, enabledTransitions);
    QList<QAbstractState*> enteredStates = enterStates(event, enabledTransitions);
#ifndef QT_NO_PROPERTIES
    applyProperties(enabledTransitions, exitedStates, enteredStates);
#endif
#ifdef QSTATEMACHINE_DEBUG
    qDebug() << q_func() << ": configuration after entering states:" << configuration;
    qDebug() << q_func() << ": end microstep";
#endif
}

QList<QAbstractState*> QStateMachinePrivate::exitStates(QEvent *event, const QList<QAbstractTransition*> &enabledTransitions)
{
//    qDebug() << "exitStates(" << enabledTransitions << ')';
    QSet<QAbstractState*> statesToExit;
//    QSet<QAbstractState*> statesToSnapshot;
    for (int i = 0; i < enabledTransitions.size(); ++i) {
        QAbstractTransition *t = enabledTransitions.at(i);
        QList<QAbstractState*> lst = t->targetStates();
        if (lst.isEmpty())
            continue;
        lst.prepend(t->sourceState());
        QAbstractState *lca = findLCA(lst);
        if (lca == 0) {
            setError(QStateMachine::NoCommonAncestorForTransitionError, t->sourceState());
            lst = pendingErrorStates.toList();
            lst.prepend(t->sourceState());

            lca = findLCA(lst);
            Q_ASSERT(lca != 0);
        }

        {
            QSet<QAbstractState*>::const_iterator it;
            for (it = configuration.constBegin(); it != configuration.constEnd(); ++it) {
                QAbstractState *s = *it;
                if (isDescendantOf(s, lca))
                    statesToExit.insert(s);
            }
        }
    }
    QList<QAbstractState*> statesToExit_sorted = statesToExit.toList();
    qSort(statesToExit_sorted.begin(), statesToExit_sorted.end(), stateExitLessThan);
    for (int i = 0; i < statesToExit_sorted.size(); ++i) {
        QAbstractState *s = statesToExit_sorted.at(i);
        if (QState *grp = toStandardState(s)) {
            QList<QHistoryState*> hlst = QStatePrivate::get(grp)->historyStates();
            for (int j = 0; j < hlst.size(); ++j) {
                QHistoryState *h = hlst.at(j);
                QHistoryStatePrivate::get(h)->configuration.clear();
                QSet<QAbstractState*>::const_iterator it;
                for (it = configuration.constBegin(); it != configuration.constEnd(); ++it) {
                    QAbstractState *s0 = *it;
                    if (QHistoryStatePrivate::get(h)->historyType == QHistoryState::DeepHistory) {
                        if (isAtomic(s0) && isDescendantOf(s0, s))
                            QHistoryStatePrivate::get(h)->configuration.append(s0);
                    } else if (s0->parentState() == s) {
                        QHistoryStatePrivate::get(h)->configuration.append(s0);
                    }
                }
#ifdef QSTATEMACHINE_DEBUG
                qDebug() << q_func() << ": recorded" << ((QHistoryStatePrivate::get(h)->historyType == QHistoryState::DeepHistory) ? "deep" : "shallow")
                         << "history for" << s << "in" << h << ':' << QHistoryStatePrivate::get(h)->configuration;
#endif
            }
        }
    }
    for (int i = 0; i < statesToExit_sorted.size(); ++i) {
        QAbstractState *s = statesToExit_sorted.at(i);
#ifdef QSTATEMACHINE_DEBUG
        qDebug() << q_func() << ": exiting" << s;
#endif
        QAbstractStatePrivate::get(s)->callOnExit(event);
        configuration.remove(s);
        QAbstractStatePrivate::get(s)->emitExited();
    }
    return statesToExit_sorted;
}

void QStateMachinePrivate::executeTransitionContent(QEvent *event, const QList<QAbstractTransition*> &enabledTransitions)
{
    for (int i = 0; i < enabledTransitions.size(); ++i) {
        QAbstractTransition *t = enabledTransitions.at(i);
#ifdef QSTATEMACHINE_DEBUG
        qDebug() << q_func() << ": triggering" << t;
#endif
        QAbstractTransitionPrivate::get(t)->callOnTransition(event);
        QAbstractTransitionPrivate::get(t)->emitTriggered();
    }
}

QList<QAbstractState*> QStateMachinePrivate::enterStates(QEvent *event, const QList<QAbstractTransition*> &enabledTransitions)
{
#ifdef QSTATEMACHINE_DEBUG
    Q_Q(QStateMachine);
#endif
//    qDebug() << "enterStates(" << enabledTransitions << ')';
    QSet<QAbstractState*> statesToEnter;
    QSet<QAbstractState*> statesForDefaultEntry;

    if (pendingErrorStates.isEmpty()) {
        for (int i = 0; i < enabledTransitions.size(); ++i) {
            QAbstractTransition *t = enabledTransitions.at(i);
            QList<QAbstractState*> lst = t->targetStates();
            if (lst.isEmpty())
                continue;
            lst.prepend(t->sourceState());
            QState *lca = findLCA(lst);
            for (int j = 1; j < lst.size(); ++j) {
                QAbstractState *s = lst.at(j);
                addStatesToEnter(s, lca, statesToEnter, statesForDefaultEntry);
                if (isParallel(lca)) {
                    QList<QAbstractState*> lcac = QStatePrivate::get(lca)->childStates();
                    foreach (QAbstractState* child,lcac) {
                        if (!statesToEnter.contains(child))
                            addStatesToEnter(child,lca,statesToEnter,statesForDefaultEntry);
                    }
                }
            }
        }
    }

    // Did an error occur while selecting transitions? Then we enter the error state.
    if (!pendingErrorStates.isEmpty()) {
        statesToEnter.clear();
        statesToEnter = pendingErrorStates;
        statesForDefaultEntry = pendingErrorStatesForDefaultEntry;
        pendingErrorStates.clear();
        pendingErrorStatesForDefaultEntry.clear();
    }

    QList<QAbstractState*> statesToEnter_sorted = statesToEnter.toList();
    qSort(statesToEnter_sorted.begin(), statesToEnter_sorted.end(), stateEntryLessThan);

    for (int i = 0; i < statesToEnter_sorted.size(); ++i) {
        QAbstractState *s = statesToEnter_sorted.at(i);
#ifdef QSTATEMACHINE_DEBUG
        qDebug() << q << ": entering" << s;
#endif
        configuration.insert(s);
        registerTransitions(s);
        QAbstractStatePrivate::get(s)->callOnEntry(event);
        QAbstractStatePrivate::get(s)->emitEntered();
        if (statesForDefaultEntry.contains(s)) {
            // ### executeContent(s.initial.transition.children())
        }
        if (isFinal(s)) {
            QState *parent = s->parentState();
            if (parent) {
                if (parent != rootState()) {
#ifdef QSTATEMACHINE_DEBUG
                    qDebug() << q << ": emitting finished signal for" << parent;
#endif
                    QStatePrivate::get(parent)->emitFinished();
                }
                QState *grandparent = parent->parentState();
                if (grandparent && isParallel(grandparent)) {
                    bool allChildStatesFinal = true;
                    QList<QAbstractState*> childStates = QStatePrivate::get(grandparent)->childStates();
                    for (int j = 0; j < childStates.size(); ++j) {
                        QAbstractState *cs = childStates.at(j);
                        if (!isInFinalState(cs)) {
                            allChildStatesFinal = false;
                            break;
                        }
                    }
                    if (allChildStatesFinal && (grandparent != rootState())) {
#ifdef QSTATEMACHINE_DEBUG
                        qDebug() << q << ": emitting finished signal for" << grandparent;
#endif
                        QStatePrivate::get(grandparent)->emitFinished();
                    }
                }
            }
        }
    }
    {
        QSet<QAbstractState*>::const_iterator it;
        for (it = configuration.constBegin(); it != configuration.constEnd(); ++it) {
            if (isFinal(*it) && (*it)->parentState() == rootState()) {
                processing = false;
                stopProcessingReason = Finished;
                break;
            }
        }
    }
//    qDebug() << "configuration:" << configuration.toList();
    return statesToEnter_sorted;
}

void QStateMachinePrivate::addStatesToEnter(QAbstractState *s, QState *root,
                                            QSet<QAbstractState*> &statesToEnter,
                                            QSet<QAbstractState*> &statesForDefaultEntry)
{
    if (QHistoryState *h = toHistoryState(s)) {
        QList<QAbstractState*> hconf = QHistoryStatePrivate::get(h)->configuration;
        if (!hconf.isEmpty()) {
            for (int k = 0; k < hconf.size(); ++k) {
                QAbstractState *s0 = hconf.at(k);
                addStatesToEnter(s0, root, statesToEnter, statesForDefaultEntry);
            }
    #ifdef QSTATEMACHINE_DEBUG
            qDebug() <<q_func() << ": restoring"
                    << ((QHistoryStatePrivate::get(h)->historyType == QHistoryState::DeepHistory) ? "deep" : "shallow")
                    << "history from" << s << ':' << hconf;
    #endif
        } else {
            QList<QAbstractState*> hlst;
            if (QHistoryStatePrivate::get(h)->defaultState)
                hlst.append(QHistoryStatePrivate::get(h)->defaultState);

            if (hlst.isEmpty()) {
                setError(QStateMachine::NoDefaultStateInHistoryStateError, h);
            } else {
                for (int k = 0; k < hlst.size(); ++k) {
                    QAbstractState *s0 = hlst.at(k);
                    addStatesToEnter(s0, root, statesToEnter, statesForDefaultEntry);
                }
    #ifdef QSTATEMACHINE_DEBUG
                qDebug() << q_func() << ": initial history targets for" << s << ':' << hlst;
    #endif
            }
        }
    } else {
            if (s == rootState()) {
                // Error has already been set by exitStates().
                Q_ASSERT(error != QStateMachine::NoError);
                return;
            }
        statesToEnter.insert(s);
        if (isParallel(s)) {
            QState *grp = toStandardState(s);
            QList<QAbstractState*> lst = QStatePrivate::get(grp)->childStates();
            for (int i = 0; i < lst.size(); ++i) {
                QAbstractState *child = lst.at(i);
                addStatesToEnter(child, grp, statesToEnter, statesForDefaultEntry);
            }
        } else if (isCompound(s)) {
            statesForDefaultEntry.insert(s);
            QState *grp = toStandardState(s);
            QAbstractState *initial = grp->initialState();
            if (initial != 0) {
                            Q_ASSERT(initial->machine() == q_func());
                addStatesToEnter(initial, grp, statesToEnter, statesForDefaultEntry);
            } else {
                setError(QStateMachine::NoInitialStateError, grp);
                return;
            }
        }
        QList<QState*> ancs = properAncestors(s, root);
        for (int i = 0; i < ancs.size(); ++i) {
            QState *anc = ancs.at(i);
            if (!anc->parentState())
                continue;
            statesToEnter.insert(anc);
            if (isParallel(anc)) {
                QList<QAbstractState*> lst = QStatePrivate::get(anc)->childStates();
                for (int j = 0; j < lst.size(); ++j) {
                    QAbstractState *child = lst.at(j);
                    bool hasDescendantInList = false;
                    QSet<QAbstractState*>::const_iterator it;
                    for (it = statesToEnter.constBegin(); it != statesToEnter.constEnd(); ++it) {
                        if (isDescendantOf(*it, child)) {
                            hasDescendantInList = true;
                            break;
                        }
                    }
                    if (!hasDescendantInList)
                        addStatesToEnter(child, anc, statesToEnter, statesForDefaultEntry);
                }
            }
        }
    }
}

#ifndef QT_NO_PROPERTIES

void QStateMachinePrivate::applyProperties(const QList<QAbstractTransition*> &transitionList,
                                           const QList<QAbstractState*> &exitedStates,
                                           const QList<QAbstractState*> &enteredStates)
{
#ifdef QT_NO_ANIMATION
    Q_UNUSED(transitionList);
    Q_UNUSED(exitedStates);
#else
    Q_Q(QStateMachine);
#endif
    // Process the property assignments of the entered states.
    QHash<QAbstractState*, QList<QPropertyAssignment> > propertyAssignmentsForState;
    QHash<RestorableId, QVariant> pendingRestorables = registeredRestorables;
    for (int i = 0; i < enteredStates.size(); ++i) {
        QState *s = toStandardState(enteredStates.at(i));
        if (!s)
            continue;

        QList<QPropertyAssignment> assignments = QStatePrivate::get(s)->propertyAssignments;
        for (int j = 0; j < assignments.size(); ++j) {
            const QPropertyAssignment &assn = assignments.at(j);
            if (globalRestorePolicy == QStateMachine::RestoreProperties) {
                registerRestorable(assn.object, assn.propertyName);
            }
            pendingRestorables.remove(RestorableId(assn.object, assn.propertyName));
            propertyAssignmentsForState[s].append(assn);
        }

        // Remove pending restorables for all parent states to avoid restoring properties
        // before the state that assigned them is exited. If state does not explicitly
        // assign a property which is assigned by the parent, it inherits the parent's assignment.
        QState *parentState = s;
        while ((parentState = parentState->parentState()) != 0) {
            assignments = QStatePrivate::get(parentState)->propertyAssignments;
            for (int j=0; j<assignments.size(); ++j) {
                const QPropertyAssignment &assn = assignments.at(j);
                int c = pendingRestorables.remove(RestorableId(assn.object, assn.propertyName));
                if (c > 0)
                    propertyAssignmentsForState[s].append(assn);
            }
        }
    }
    if (!pendingRestorables.isEmpty()) {
        QAbstractState *s;
        if (!enteredStates.isEmpty())
            s = enteredStates.last(); // ### handle if parallel
        else
            s = 0;
        propertyAssignmentsForState[s] << restorablesToPropertyList(pendingRestorables);
    }

#ifndef QT_NO_ANIMATION
    // Gracefully terminate playing animations for states that are exited.
    for (int i = 0; i < exitedStates.size(); ++i) {
        QAbstractState *s = exitedStates.at(i);
        QList<QAbstractAnimation*> animations = animationsForState.take(s);
        for (int j = 0; j < animations.size(); ++j) {
            QAbstractAnimation *anim = animations.at(j);
            QObject::disconnect(anim, SIGNAL(finished()), q, SLOT(_q_animationFinished()));
            stateForAnimation.remove(anim);

            // Stop the (top-level) animation.
            // ### Stopping nested animation has weird behavior.
            QAbstractAnimation *topLevelAnim = anim;
            while (QAnimationGroup *group = topLevelAnim->group())
                topLevelAnim = group;
            topLevelAnim->stop();

            if (resetAnimationEndValues.contains(anim)) {
                qobject_cast<QVariantAnimation*>(anim)->setEndValue(QVariant()); // ### generalize
                resetAnimationEndValues.remove(anim);
            }
            QPropertyAssignment assn = propertyForAnimation.take(anim);
            Q_ASSERT(assn.object != 0);
            // If there is no property assignment that sets this property,
            // set the property to its target value.
            bool found = false;
            QHash<QAbstractState*, QList<QPropertyAssignment> >::const_iterator it;
            for (it = propertyAssignmentsForState.constBegin(); it != propertyAssignmentsForState.constEnd(); ++it) {
                const QList<QPropertyAssignment> &assignments = it.value();
                for (int k = 0; k < assignments.size(); ++k) {
                    if ((assignments.at(k).object == assn.object)
                        && (assignments.at(k).propertyName == assn.propertyName)) {
                        found = true;
                        break;
                    }
                }
            }
            if (!found) {
                assn.object->setProperty(assn.propertyName, assn.value);
            }
        }
    }

    // Find the animations to use for the state change.
    QList<QAbstractAnimation*> selectedAnimations;
    if (animated) {
        for (int i = 0; i < transitionList.size(); ++i) {
            QAbstractTransition *transition = transitionList.at(i);

            selectedAnimations << transition->animations();
            selectedAnimations << defaultAnimationsForSource.values(transition->sourceState());

            QList<QAbstractState *> targetStates = transition->targetStates();
            for (int j=0; j<targetStates.size(); ++j)
                selectedAnimations << defaultAnimationsForTarget.values(targetStates.at(j));
        }
        selectedAnimations << defaultAnimations;
    }

    // Initialize animations from property assignments.
    for (int i = 0; i < selectedAnimations.size(); ++i) {
        QAbstractAnimation *anim = selectedAnimations.at(i);
        QHash<QAbstractState*, QList<QPropertyAssignment> >::iterator it;
        for (it = propertyAssignmentsForState.begin(); it != propertyAssignmentsForState.end(); ) {
            QList<QPropertyAssignment>::iterator it2;
            QAbstractState *s = it.key();
            QList<QPropertyAssignment> &assignments = it.value();
            for (it2 = assignments.begin(); it2 != assignments.end(); ) {
                QPair<QList<QAbstractAnimation*>, QList<QAbstractAnimation*> > ret;
                ret = initializeAnimation(anim, *it2);
                QList<QAbstractAnimation*> handlers = ret.first;
                if (!handlers.isEmpty()) {
                    for (int j = 0; j < handlers.size(); ++j) {
                        QAbstractAnimation *a = handlers.at(j);
                        propertyForAnimation.insert(a, *it2);
                        stateForAnimation.insert(a, s);
                        animationsForState[s].append(a);
                        // ### connect to just the top-level animation?
                        QObject::connect(a, SIGNAL(finished()), q, SLOT(_q_animationFinished()), Qt::UniqueConnection);
                    }
                    it2 = assignments.erase(it2);
                } else {
                    ++it2;
                }
                for (int j = 0; j < ret.second.size(); ++j)
                    resetAnimationEndValues.insert(ret.second.at(j));
            }
            if (assignments.isEmpty())
                it = propertyAssignmentsForState.erase(it);
            else
                ++it;
        }
        // We require that at least one animation is valid.
        // ### generalize
        QList<QVariantAnimation*> variantAnims = anim->findChildren<QVariantAnimation*>();
        if (QVariantAnimation *va = qobject_cast<QVariantAnimation*>(anim))
            variantAnims.append(va);

        bool hasValidEndValue = false;
        for (int j = 0; j < variantAnims.size(); ++j) {
            if (variantAnims.at(j)->endValue().isValid()) {
                hasValidEndValue = true;
                break;
            }
        }

        if (hasValidEndValue) {
            if (anim->state() == QAbstractAnimation::Running) {
                // The animation is still running. This can happen if the
                // animation is a group, and one of its children just finished,
                // and that caused a state to emit its propertiesAssigned() signal, and
                // that triggered a transition in the machine.
                // Just stop the animation so it is correctly restarted again.
                anim->stop();
            }
            anim->start();
        }
    }
#endif // !QT_NO_ANIMATION

    // Immediately set the properties that are not animated.
    {
        QHash<QAbstractState*, QList<QPropertyAssignment> >::const_iterator it;
        for (it = propertyAssignmentsForState.constBegin(); it != propertyAssignmentsForState.constEnd(); ++it) {
            const QList<QPropertyAssignment> &assignments = it.value();
            for (int i = 0; i < assignments.size(); ++i) {
                const QPropertyAssignment &assn = assignments.at(i);
                assn.object->setProperty(assn.propertyName, assn.value);
            }
        }
    }

    // Emit propertiesAssigned signal for entered states that have no animated properties.
    for (int i = 0; i < enteredStates.size(); ++i) {
        QState *s = toStandardState(enteredStates.at(i));
        if (s
#ifndef QT_NO_ANIMATION
            && !animationsForState.contains(s)
#endif
            )
            QStatePrivate::get(s)->emitPropertiesAssigned();
    }
}

#endif // QT_NO_PROPERTIES

bool QStateMachinePrivate::isFinal(const QAbstractState *s)
{
    return s && (QAbstractStatePrivate::get(s)->stateType == QAbstractStatePrivate::FinalState);
}

bool QStateMachinePrivate::isParallel(const QAbstractState *s)
{
    const QState *ss = toStandardState(s);
    return ss && (QStatePrivate::get(ss)->childMode == QState::ParallelStates);
}

bool QStateMachinePrivate::isCompound(const QAbstractState *s) const
{
    const QState *group = toStandardState(s);
    if (!group)
        return false;
    bool isMachine = QStatePrivate::get(group)->isMachine;
    // Don't treat the machine as compound if it's a sub-state of this machine
    if (isMachine && (group != rootState()))
        return false;
    return (!isParallel(group) && !QStatePrivate::get(group)->childStates().isEmpty())
        || isMachine;
}

bool QStateMachinePrivate::isAtomic(const QAbstractState *s) const
{
    const QState *ss = toStandardState(s);
    return (ss && QStatePrivate::get(ss)->childStates().isEmpty())
        || isFinal(s)
        // Treat the machine as atomic if it's a sub-state of this machine
        || (ss && QStatePrivate::get(ss)->isMachine && (ss != rootState()));
}


bool QStateMachinePrivate::isDescendantOf(const QAbstractState *state, const QAbstractState *other)
{
    Q_ASSERT(state != 0);
    for (QAbstractState *s = state->parentState(); s != 0; s = s->parentState()) {
        if (s == other)
            return true;
    }
    return false;
}

QList<QState*> QStateMachinePrivate::properAncestors(const QAbstractState *state, const QState *upperBound)
{
    Q_ASSERT(state != 0);
    QList<QState*> result;
    for (QState *s = state->parentState(); s && s != upperBound; s = s->parentState()) {
        result.append(s);
    }
    return result;
}

QState *QStateMachinePrivate::toStandardState(QAbstractState *state)
{
    if (state && (QAbstractStatePrivate::get(state)->stateType == QAbstractStatePrivate::StandardState))
        return static_cast<QState*>(state);
    return 0;
}

const QState *QStateMachinePrivate::toStandardState(const QAbstractState *state)
{
    if (state && (QAbstractStatePrivate::get(state)->stateType == QAbstractStatePrivate::StandardState))
        return static_cast<const QState*>(state);
    return 0;
}

QFinalState *QStateMachinePrivate::toFinalState(QAbstractState *state)
{
    if (state && (QAbstractStatePrivate::get(state)->stateType == QAbstractStatePrivate::FinalState))
        return static_cast<QFinalState*>(state);
    return 0;
}

QHistoryState *QStateMachinePrivate::toHistoryState(QAbstractState *state)
{
    if (state && (QAbstractStatePrivate::get(state)->stateType == QAbstractStatePrivate::HistoryState))
        return static_cast<QHistoryState*>(state);
    return 0;
}

bool QStateMachinePrivate::isInFinalState(QAbstractState* s) const
{
    if (isCompound(s)) {
        QState *grp = toStandardState(s);
        QList<QAbstractState*> lst = QStatePrivate::get(grp)->childStates();
        for (int i = 0; i < lst.size(); ++i) {
            QAbstractState *cs = lst.at(i);
            if (isFinal(cs) && configuration.contains(cs))
                return true;
        }
        return false;
    } else if (isParallel(s)) {
        QState *grp = toStandardState(s);
        QList<QAbstractState*> lst = QStatePrivate::get(grp)->childStates();
        for (int i = 0; i < lst.size(); ++i) {
            QAbstractState *cs = lst.at(i);
            if (!isInFinalState(cs))
                return false;
        }
        return true;
    }
    else
        return false;
}

#ifndef QT_NO_PROPERTIES

void QStateMachinePrivate::registerRestorable(QObject *object, const QByteArray &propertyName)
{
    RestorableId id(object, propertyName);
    if (!registeredRestorables.contains(id))
        registeredRestorables.insert(id, object->property(propertyName));
}

QList<QPropertyAssignment> QStateMachinePrivate::restorablesToPropertyList(const QHash<RestorableId, QVariant> &restorables) const
{
    QList<QPropertyAssignment> result;
    QHash<RestorableId, QVariant>::const_iterator it;
    for (it = restorables.constBegin(); it != restorables.constEnd(); ++it) {
//        qDebug() << "restorable:" << it.key().first << it.key().second << it.value();
        result.append(QPropertyAssignment(it.key().first, it.key().second, it.value(), /*explicitlySet=*/false));
    }
    return result;
}

bool QStateMachinePrivate::hasRestorable(QObject *object, const QByteArray &propertyName) const
{
    return registeredRestorables.contains(RestorableId(object, propertyName));
}

QVariant QStateMachinePrivate::restorableValue(QObject *object, const QByteArray &propertyName) const
{
    return registeredRestorables.value(RestorableId(object, propertyName), QVariant());
}


void QStateMachinePrivate::unregisterRestorable(QObject *object, const QByteArray &propertyName)
{
//    qDebug() << "unregisterRestorable(" << object << propertyName << ')';
    RestorableId id(object, propertyName);
    registeredRestorables.remove(id);
}

#endif // QT_NO_PROPERTIES

QAbstractState *QStateMachinePrivate::findErrorState(QAbstractState *context)
{
    // Find error state recursively in parent hierarchy if not set explicitly for context state
    QAbstractState *errorState = 0;
    if (context != 0) {
        QState *s = toStandardState(context);
        if (s != 0)
            errorState = s->errorState();

        if (errorState == 0)
            errorState = findErrorState(context->parentState());
    }

    return errorState;
}

void QStateMachinePrivate::setError(QStateMachine::Error errorCode, QAbstractState *currentContext)
{
    Q_Q(QStateMachine);

    error = errorCode;
    switch (errorCode) {
    case QStateMachine::NoInitialStateError:
        Q_ASSERT(currentContext != 0);

        errorString = QStateMachine::tr("Missing initial state in compound state '%1'")
                        .arg(currentContext->objectName());

        break;
    case QStateMachine::NoDefaultStateInHistoryStateError:
        Q_ASSERT(currentContext != 0);

        errorString = QStateMachine::tr("Missing default state in history state '%1'")
                        .arg(currentContext->objectName());
        break;

    case QStateMachine::NoCommonAncestorForTransitionError:
        Q_ASSERT(currentContext != 0);

        errorString = QStateMachine::tr("No common ancestor for targets and source of transition from state '%1'")
                        .arg(currentContext->objectName());
        break;
    default:
        errorString = QStateMachine::tr("Unknown error");
    };

    pendingErrorStates.clear();
    pendingErrorStatesForDefaultEntry.clear();

    QAbstractState *currentErrorState = findErrorState(currentContext);

    // Avoid infinite loop if the error state itself has an error
    if (currentContext == currentErrorState)
        currentErrorState = 0;

    Q_ASSERT(currentErrorState != rootState());

    if (currentErrorState != 0) {
        QState *lca = findLCA(QList<QAbstractState*>() << currentErrorState << currentContext);
        addStatesToEnter(currentErrorState, lca, pendingErrorStates, pendingErrorStatesForDefaultEntry);
    } else {
        qWarning("Unrecoverable error detected in running state machine: %s",
                 qPrintable(errorString));
        q->stop();
    }
}

#ifndef QT_NO_ANIMATION

QPair<QList<QAbstractAnimation*>, QList<QAbstractAnimation*> >
QStateMachinePrivate::initializeAnimation(QAbstractAnimation *abstractAnimation,
                                          const QPropertyAssignment &prop)
{
    QList<QAbstractAnimation*> handledAnimations;
    QList<QAbstractAnimation*> localResetEndValues;
    QAnimationGroup *group = qobject_cast<QAnimationGroup*>(abstractAnimation);
    if (group) {
        for (int i = 0; i < group->animationCount(); ++i) {
            QAbstractAnimation *animationChild = group->animationAt(i);
            QPair<QList<QAbstractAnimation*>, QList<QAbstractAnimation*> > ret;
            ret = initializeAnimation(animationChild, prop);
            handledAnimations << ret.first;
            localResetEndValues << ret.second;
        }
    } else {
        QPropertyAnimation *animation = qobject_cast<QPropertyAnimation *>(abstractAnimation);
        if (animation != 0
            && prop.object == animation->targetObject()
            && prop.propertyName == animation->propertyName()) {

            // Only change end value if it is undefined
            if (!animation->endValue().isValid()) {
                animation->setEndValue(prop.value);
                localResetEndValues.append(animation);
            }
            handledAnimations.append(animation);
        }
    }
    return qMakePair(handledAnimations, localResetEndValues);
}

void QStateMachinePrivate::_q_animationFinished()
{
    Q_Q(QStateMachine);
    QAbstractAnimation *anim = qobject_cast<QAbstractAnimation*>(q->sender());
    Q_ASSERT(anim != 0);
    QObject::disconnect(anim, SIGNAL(finished()), q, SLOT(_q_animationFinished()));
    if (resetAnimationEndValues.contains(anim)) {
        qobject_cast<QVariantAnimation*>(anim)->setEndValue(QVariant()); // ### generalize
        resetAnimationEndValues.remove(anim);
    }

#ifndef QT_NO_PROPERTIES
    // Set the final property value.
    QPropertyAssignment assn = propertyForAnimation.take(anim);
    Q_ASSERT(assn.object != 0);
    assn.object->setProperty(assn.propertyName, assn.value);
    if (!assn.explicitlySet)
        unregisterRestorable(assn.object, assn.propertyName);
#endif

    QAbstractState *state = stateForAnimation.take(anim);
    Q_ASSERT(state != 0);
    QHash<QAbstractState*, QList<QAbstractAnimation*> >::iterator it;
    it = animationsForState.find(state);
    Q_ASSERT(it != animationsForState.end());
    QList<QAbstractAnimation*> &animations = it.value();
    animations.removeOne(anim);
    if (animations.isEmpty()) {
        animationsForState.erase(it);
        QStatePrivate::get(toStandardState(state))->emitPropertiesAssigned();
    }
}

#endif // !QT_NO_ANIMATION

namespace {

class StartState : public QState
{
public:
    StartState(QState *parent)
        : QState(parent) {}
protected:
    void onEntry(QEvent *) {}
    void onExit(QEvent *) {}
};

class InitialTransition : public QAbstractTransition
{
public:
    InitialTransition(QAbstractState *target)
        : QAbstractTransition()
    { setTargetState(target); }
protected:
    virtual bool eventTest(QEvent *) { return true; }
    virtual void onTransition(QEvent *) {}
};

} // namespace

QState *QStateMachinePrivate::startState()
{
    Q_Q(QStateMachine);
    if (_startState == 0)
        _startState = new StartState(q);
    return _startState;
}

void QStateMachinePrivate::removeStartState()
{
    delete _startState;
    _startState = 0;
}

void QStateMachinePrivate::clearHistory()
{
    Q_Q(QStateMachine);
    QList<QHistoryState*> historyStates = q->findChildren<QHistoryState*>();
    for (int i = 0; i < historyStates.size(); ++i) {
        QHistoryState *h = historyStates.at(i);
        QHistoryStatePrivate::get(h)->configuration.clear();
    }
}

void QStateMachinePrivate::_q_start()
{
    Q_Q(QStateMachine);
    Q_ASSERT(state == Starting);
    Q_ASSERT(rootState() != 0);
    QAbstractState *initial = rootState()->initialState();
    configuration.clear();
    qDeleteAll(internalEventQueue);
    internalEventQueue.clear();
    qDeleteAll(externalEventQueue);
    externalEventQueue.clear();
    clearHistory();

#ifdef QSTATEMACHINE_DEBUG
    qDebug() << q << ": starting";
#endif
    state = Running;
    processingScheduled = true; // we call _q_process() below
    emit q->started();

    QState *start = startState();
    Q_ASSERT(start != 0);

    QList<QAbstractTransition*> transitions = QStatePrivate::get(start)->transitions();

    // If a transition has already been added, then we skip this step, as the
    // initial transition in that case has been overridden.
    if (transitions.isEmpty()) {
        QAbstractTransition *initialTransition = new InitialTransition(initial);
        start->addTransition(initialTransition);
        transitions.append(initialTransition);
    }

    QEvent nullEvent(QEvent::None);
    executeTransitionContent(&nullEvent, transitions);
    QList<QAbstractState*> enteredStates = enterStates(&nullEvent, transitions);
#ifndef QT_NO_PROPERTIES
    applyProperties(transitions, QList<QAbstractState*>() << start,
                    enteredStates);
#endif
    removeStartState();

#ifdef QSTATEMACHINE_DEBUG
    qDebug() << q << ": initial configuration:" << configuration;
#endif
    _q_process();
}

void QStateMachinePrivate::_q_process()
{
    Q_Q(QStateMachine);
    Q_ASSERT(state == Running);
    Q_ASSERT(!processing);
    processing = true;
    processingScheduled = false;
#ifdef QSTATEMACHINE_DEBUG
    qDebug() << q << ": starting the event processing loop";
#endif
    while (processing) {
        if (stop) {
            processing = false;
            break;
        }
        QSet<QAbstractTransition*> enabledTransitions;
        QEvent *e = new QEvent(QEvent::None);
        enabledTransitions = selectTransitions(e);
        if (enabledTransitions.isEmpty()) {
            delete e;
            e = 0;
        }
        if (enabledTransitions.isEmpty() && ((e = dequeueInternalEvent()) != 0)) {
#ifdef QSTATEMACHINE_DEBUG
            qDebug() << q << ": dequeued internal event" << e << "of type" << e->type();
#endif
            enabledTransitions = selectTransitions(e);
            if (enabledTransitions.isEmpty()) {
                delete e;
                e = 0;
            }
        }
        if (enabledTransitions.isEmpty()) {
            if ((e = dequeueExternalEvent()) != 0) {
#ifdef QSTATEMACHINE_DEBUG
                qDebug() << q << ": dequeued external event" << e << "of type" << e->type();
#endif
                enabledTransitions = selectTransitions(e);
                if (enabledTransitions.isEmpty()) {
                    delete e;
                    e = 0;
                }
            } else {
                if (isInternalEventQueueEmpty()) {
                    processing = false;
                    stopProcessingReason = EventQueueEmpty;
                }
            }
        }
        if (!enabledTransitions.isEmpty()) {
            q->beginMicrostep(e);
            microstep(e, enabledTransitions.toList());
            q->endMicrostep(e);
        }
#ifdef QSTATEMACHINE_DEBUG
        else {
            qDebug() << q << ": no transitions enabled";
        }
#endif
        delete e;
    }
#ifdef QSTATEMACHINE_DEBUG
    qDebug() << q << ": finished the event processing loop";
#endif
    if (stop) {
        stop = false;
        stopProcessingReason = Stopped;
    }

    switch (stopProcessingReason) {
    case EventQueueEmpty:
        break;
    case Finished:
        state = NotRunning;
        cancelAllDelayedEvents();
        unregisterAllTransitions();
        emit q->finished();
        break;
    case Stopped:
        state = NotRunning;
        cancelAllDelayedEvents();
        unregisterAllTransitions();
        emit q->stopped();
        break;
    }
}

void QStateMachinePrivate::postInternalEvent(QEvent *e)
{
    QMutexLocker locker(&internalEventMutex);
    internalEventQueue.append(e);
}

void QStateMachinePrivate::postExternalEvent(QEvent *e)
{
    QMutexLocker locker(&externalEventMutex);
    externalEventQueue.append(e);
}

QEvent *QStateMachinePrivate::dequeueInternalEvent()
{
    QMutexLocker locker(&internalEventMutex);
    if (internalEventQueue.isEmpty())
        return 0;
    return internalEventQueue.takeFirst();
}

QEvent *QStateMachinePrivate::dequeueExternalEvent()
{
    QMutexLocker locker(&externalEventMutex);
    if (externalEventQueue.isEmpty())
        return 0;
    return externalEventQueue.takeFirst();
}

bool QStateMachinePrivate::isInternalEventQueueEmpty()
{
    QMutexLocker locker(&internalEventMutex);
    return internalEventQueue.isEmpty();
}

bool QStateMachinePrivate::isExternalEventQueueEmpty()
{
    QMutexLocker locker(&externalEventMutex);
    return externalEventQueue.isEmpty();
}

void QStateMachinePrivate::processEvents(EventProcessingMode processingMode)
{
    Q_Q(QStateMachine);
    if ((state != Running) || processing || processingScheduled)
        return;
    switch (processingMode) {
    case DirectProcessing:
        if (QThread::currentThread() == q->thread()) {
            _q_process();
            break;
        } // fallthrough -- processing must be done in the machine thread
    case QueuedProcessing:
        processingScheduled = true;
        QMetaObject::invokeMethod(q, "_q_process", Qt::QueuedConnection);
        break;
    }
}

void QStateMachinePrivate::cancelAllDelayedEvents()
{
    Q_Q(QStateMachine);
    QMutexLocker locker(&delayedEventsMutex);
    QHash<int, QEvent*>::const_iterator it;
    for (it = delayedEvents.constBegin(); it != delayedEvents.constEnd(); ++it) {
        int id = it.key();
        QEvent *e = it.value();
        q->killTimer(id);
        delete e;
    }
    delayedEvents.clear();
}

namespace _QStateMachine_Internal{

class GoToStateTransition : public QAbstractTransition
{
public:
    GoToStateTransition(QAbstractState *target)
        : QAbstractTransition()
    { setTargetState(target); }
protected:
    void onTransition(QEvent *) { deleteLater(); }
    bool eventTest(QEvent *) { return true; }
};

} // namespace
// mingw compiler tries to export QObject::findChild<GoToStateTransition>(),
// which doesn't work if its in an anonymous namespace.
using namespace _QStateMachine_Internal;
void QStateMachinePrivate::goToState(QAbstractState *targetState)
{
    if (!targetState) {
        qWarning("QStateMachine::goToState(): cannot go to null state");
        return;
    }

    if (configuration.contains(targetState))
        return;

    QState *sourceState = 0;
    if (state == Running) {
        QSet<QAbstractState*>::const_iterator it;
        for (it = configuration.constBegin(); it != configuration.constEnd(); ++it) {
            sourceState = toStandardState(*it);
            if (sourceState != 0)
                break;
        }
    } else {
        sourceState = startState();
    }

    Q_ASSERT(sourceState != 0);
    // Reuse previous GoToStateTransition in case of several calls to
    // goToState() in a row.
    GoToStateTransition *trans = sourceState->findChild<GoToStateTransition*>();
    if (!trans) {
        trans = new GoToStateTransition(targetState);
        sourceState->addTransition(trans);
    } else {
        trans->setTargetState(targetState);
    }

    processEvents(QueuedProcessing);
}

void QStateMachinePrivate::registerTransitions(QAbstractState *state)
{
    QState *group = toStandardState(state);
    if (!group)
        return;
    QList<QAbstractTransition*> transitions = QStatePrivate::get(group)->transitions();
    for (int i = 0; i < transitions.size(); ++i) {
        QAbstractTransition *t = transitions.at(i);
        if (QSignalTransition *st = qobject_cast<QSignalTransition*>(t)) {
            registerSignalTransition(st);
        }
#ifndef QT_NO_STATEMACHINE_EVENTFILTER
        else if (QEventTransition *oet = qobject_cast<QEventTransition*>(t)) {
            registerEventTransition(oet);
        }
#endif
    }
}

void QStateMachinePrivate::unregisterTransition(QAbstractTransition *transition)
{
    if (QSignalTransition *st = qobject_cast<QSignalTransition*>(transition)) {
        unregisterSignalTransition(st);
    }
#ifndef QT_NO_STATEMACHINE_EVENTFILTER
    else if (QEventTransition *oet = qobject_cast<QEventTransition*>(transition)) {
        unregisterEventTransition(oet);
    }
#endif
}

void QStateMachinePrivate::registerSignalTransition(QSignalTransition *transition)
{
    Q_Q(QStateMachine);
    if (QSignalTransitionPrivate::get(transition)->signalIndex != -1)
        return; // already registered
    QObject *sender = QSignalTransitionPrivate::get(transition)->sender;
    if (!sender)
        return;
    QByteArray signal = QSignalTransitionPrivate::get(transition)->signal;
    if (signal.startsWith('0'+QSIGNAL_CODE))
        signal.remove(0, 1);
    const QMetaObject *meta = sender->metaObject();
    int signalIndex = meta->indexOfSignal(signal);
    int originalSignalIndex = signalIndex;
    if (signalIndex == -1) {
        signalIndex = meta->indexOfSignal(QMetaObject::normalizedSignature(signal));
        if (signalIndex == -1) {
            qWarning("QSignalTransition: no such signal: %s::%s",
                     meta->className(), signal.constData());
            return;
        }
    }
    // The signal index we actually want to connect to is the one
    // that is going to be sent, i.e. the non-cloned original index.
    while (meta->method(signalIndex).attributes() & QMetaMethod::Cloned)
        --signalIndex;

    QVector<int> &connectedSignalIndexes = connections[sender];
    if (connectedSignalIndexes.size() <= signalIndex)
        connectedSignalIndexes.resize(signalIndex+1);
    if (connectedSignalIndexes.at(signalIndex) == 0) {
        if (!signalEventGenerator)
            signalEventGenerator = new QSignalEventGenerator(q);
        bool ok = QMetaObject::connect(sender, signalIndex, signalEventGenerator,
                                       signalEventGenerator->metaObject()->methodOffset());
        if (!ok) {
#ifdef QSTATEMACHINE_DEBUG
            qDebug() << q << ": FAILED to add signal transition from" << transition->sourceState()
                     << ": ( sender =" << sender << ", signal =" << signal
                     << ", targets =" << transition->targetStates() << ')';
#endif
            return;
        }
    }
    ++connectedSignalIndexes[signalIndex];
    QSignalTransitionPrivate::get(transition)->signalIndex = signalIndex;
    QSignalTransitionPrivate::get(transition)->originalSignalIndex = originalSignalIndex;
#ifdef QSTATEMACHINE_DEBUG
    qDebug() << q << ": added signal transition from" << transition->sourceState()
             << ": ( sender =" << sender << ", signal =" << signal
             << ", targets =" << transition->targetStates() << ')';
#endif
}

void QStateMachinePrivate::unregisterSignalTransition(QSignalTransition *transition)
{
    int signalIndex = QSignalTransitionPrivate::get(transition)->signalIndex;
    if (signalIndex == -1)
        return; // not registered
    QSignalTransitionPrivate::get(transition)->signalIndex = -1;
    const QObject *sender = QSignalTransitionPrivate::get(transition)->sender;
    QVector<int> &connectedSignalIndexes = connections[sender];
    Q_ASSERT(connectedSignalIndexes.size() > signalIndex);
    Q_ASSERT(connectedSignalIndexes.at(signalIndex) != 0);
    if (--connectedSignalIndexes[signalIndex] == 0) {
        Q_ASSERT(signalEventGenerator != 0);
        QMetaObject::disconnect(sender, signalIndex, signalEventGenerator,
                                signalEventGenerator->metaObject()->methodOffset());
        int sum = 0;
        for (int i = 0; i < connectedSignalIndexes.size(); ++i)
            sum += connectedSignalIndexes.at(i);
        if (sum == 0)
            connections.remove(sender);
    }
}

void QStateMachinePrivate::unregisterAllTransitions()
{
    Q_Q(QStateMachine);
    {
        QList<QSignalTransition*> transitions = rootState()->findChildren<QSignalTransition*>();
        for (int i = 0; i < transitions.size(); ++i) {
            QSignalTransition *t = transitions.at(i);
            if (t->machine() == q)
                unregisterSignalTransition(t);
        }
    }
    {
        QList<QEventTransition*> transitions = rootState()->findChildren<QEventTransition*>();
        for (int i = 0; i < transitions.size(); ++i) {
            QEventTransition *t = transitions.at(i);
            if (t->machine() == q)
                unregisterEventTransition(t);
        }
    }
}

#ifndef QT_NO_STATEMACHINE_EVENTFILTER
void QStateMachinePrivate::registerEventTransition(QEventTransition *transition)
{
    Q_Q(QStateMachine);
    if (QEventTransitionPrivate::get(transition)->registered)
        return;
    if (transition->eventType() >= QEvent::User) {
        qWarning("QObject event transitions are not supported for custom types");
        return;
    }
    QObject *object = QEventTransitionPrivate::get(transition)->object;
    if (!object)
        return;
    QObjectPrivate *od = QObjectPrivate::get(object);
    if (!od->eventFilters.contains(q))
        object->installEventFilter(q);
    ++qobjectEvents[object][transition->eventType()];
    QEventTransitionPrivate::get(transition)->registered = true;
#ifdef QSTATEMACHINE_DEBUG
    qDebug() << q << ": added event transition from" << transition->sourceState()
             << ": ( object =" << object << ", event =" << transition->eventType()
             << ", targets =" << transition->targetStates() << ')';
#endif
}

void QStateMachinePrivate::unregisterEventTransition(QEventTransition *transition)
{
    Q_Q(QStateMachine);
    if (!QEventTransitionPrivate::get(transition)->registered)
        return;
    QObject *object = QEventTransitionPrivate::get(transition)->object;
    QHash<QEvent::Type, int> &events = qobjectEvents[object];
    Q_ASSERT(events.value(transition->eventType()) > 0);
    if (--events[transition->eventType()] == 0) {
        events.remove(transition->eventType());
        int sum = 0;
        QHash<QEvent::Type, int>::const_iterator it;
        for (it = events.constBegin(); it != events.constEnd(); ++it)
            sum += it.value();
        if (sum == 0) {
            qobjectEvents.remove(object);
            object->removeEventFilter(q);
        }
    }
    QEventTransitionPrivate::get(transition)->registered = false;
}

void QStateMachinePrivate::handleFilteredEvent(QObject *watched, QEvent *event)
{
    if (qobjectEvents.value(watched).contains(event->type())) {
        postInternalEvent(new QStateMachine::WrappedEvent(watched, handler->cloneEvent(event)));
        processEvents(DirectProcessing);
    }
}
#endif

void QStateMachinePrivate::handleTransitionSignal(QObject *sender, int signalIndex,
                                                  void **argv)
{
    Q_ASSERT(connections[sender].at(signalIndex) != 0);
    const QMetaObject *meta = sender->metaObject();
    QMetaMethod method = meta->method(signalIndex);
    QList<QByteArray> parameterTypes = method.parameterTypes();
    int argc = parameterTypes.count();
    QList<QVariant> vargs;
    for (int i = 0; i < argc; ++i) {
        int type = QMetaType::type(parameterTypes.at(i));
        vargs.append(QVariant(type, argv[i+1]));
    }

#ifdef QSTATEMACHINE_DEBUG
    qDebug() << q_func() << ": sending signal event ( sender =" << sender
             << ", signal =" << sender->metaObject()->method(signalIndex).signature() << ')';
#endif
    postInternalEvent(new QStateMachine::SignalEvent(sender, signalIndex, vargs));
    processEvents(DirectProcessing);
}

QStateMachine::QStateMachine(QObject *parent)
    : QState(*new QStateMachinePrivate, /*parentState=*/0)
{
    // Can't pass the parent to the QState constructor, as it expects a QState
    // But this works as expected regardless of whether parent is a QState or not
    setParent(parent);
}

QStateMachine::QStateMachine(QStateMachinePrivate &dd, QObject *parent)
    : QState(dd, /*parentState=*/0)
{
    setParent(parent);
}

QStateMachine::~QStateMachine()
{
}

QStateMachine::Error QStateMachine::error() const
{
    Q_D(const QStateMachine);
    return d->error;
}

QString QStateMachine::errorString() const
{
    Q_D(const QStateMachine);
    return d->errorString;
}

void QStateMachine::clearError()
{
    Q_D(QStateMachine);
    d->errorString.clear();
    d->error = NoError;
}

QStateMachine::RestorePolicy QStateMachine::globalRestorePolicy() const
{
    Q_D(const QStateMachine);
    return d->globalRestorePolicy;
}

void QStateMachine::setGlobalRestorePolicy(QStateMachine::RestorePolicy restorePolicy)
{
    Q_D(QStateMachine);
    d->globalRestorePolicy = restorePolicy;
}

void QStateMachine::addState(QAbstractState *state)
{
    if (!state) {
        qWarning("QStateMachine::addState: cannot add null state");
        return;
    }
    if (QAbstractStatePrivate::get(state)->machine() == this) {
        qWarning("QStateMachine::addState: state has already been added to this machine");
        return;
    }
    state->setParent(this);
}

void QStateMachine::removeState(QAbstractState *state)
{
    if (!state) {
        qWarning("QStateMachine::removeState: cannot remove null state");
        return;
    }
    if (QAbstractStatePrivate::get(state)->machine() != this) {
        qWarning("QStateMachine::removeState: state %p's machine (%p)"
                 " is different from this machine (%p)",
                 state, QAbstractStatePrivate::get(state)->machine(), this);
        return;
    }
    state->setParent(0);
}

bool QStateMachine::isRunning() const
{
    Q_D(const QStateMachine);
    return (d->state == QStateMachinePrivate::Running);
}

void QStateMachine::start()
{
    Q_D(QStateMachine);

    if (initialState() == 0) {
        qWarning("QStateMachine::start: No initial state set for machine. Refusing to start.");
        return;
    }

    switch (d->state) {
    case QStateMachinePrivate::NotRunning:
        d->state = QStateMachinePrivate::Starting;
        QMetaObject::invokeMethod(this, "_q_start", Qt::QueuedConnection);
        break;
    case QStateMachinePrivate::Starting:
        break;
    case QStateMachinePrivate::Running:
        qWarning("QStateMachine::start(): already running");
        break;
    }
}

void QStateMachine::stop()
{
    Q_D(QStateMachine);
    switch (d->state) {
    case QStateMachinePrivate::NotRunning:
        break;
    case QStateMachinePrivate::Starting:
        // the machine will exit as soon as it enters the event processing loop
        d->stop = true;
        break;
    case QStateMachinePrivate::Running:
        d->stop = true;
        d->processEvents(QStateMachinePrivate::QueuedProcessing);
        break;
    }
}

void QStateMachine::postEvent(QEvent *event, EventPriority priority)
{
    Q_D(QStateMachine);
    if (d->state != QStateMachinePrivate::Running) {
        qWarning("QStateMachine::postEvent: cannot post event when the state machine is not running");
        return;
    }
    if (!event) {
        qWarning("QStateMachine::postEvent: cannot post null event");
        return;
    }
#ifdef QSTATEMACHINE_DEBUG
    qDebug() << this << ": posting event" << event;
#endif
    switch (priority) {
    case NormalPriority:
        d->postExternalEvent(event);
        break;
    case HighPriority:
        d->postInternalEvent(event);
        break;
    }
    d->processEvents(QStateMachinePrivate::QueuedProcessing);
}

int QStateMachine::postDelayedEvent(QEvent *event, int delay)
{
    Q_D(QStateMachine);
    if (d->state != QStateMachinePrivate::Running) {
        qWarning("QStateMachine::postDelayedEvent: cannot post event when the state machine is not running");
        return -1;
    }
    if (!event) {
        qWarning("QStateMachine::postDelayedEvent: cannot post null event");
        return -1;
    }
    if (delay < 0) {
        qWarning("QStateMachine::postDelayedEvent: delay cannot be negative");
        return -1;
    }
#ifdef QSTATEMACHINE_DEBUG
    qDebug() << this << ": posting event" << event << "with delay" << delay;
#endif
    QMutexLocker locker(&d->delayedEventsMutex);
    int tid = startTimer(delay);
    d->delayedEvents[tid] = event;
    return tid;
}

bool QStateMachine::cancelDelayedEvent(int id)
{
    Q_D(QStateMachine);
    if (d->state != QStateMachinePrivate::Running) {
        qWarning("QStateMachine::cancelDelayedEvent: the machine is not running");
        return false;
    }
    QMutexLocker locker(&d->delayedEventsMutex);
    QEvent *e = d->delayedEvents.take(id);
    if (!e)
        return false;
    killTimer(id);
    delete e;
    return true;
}

QSet<QAbstractState*> QStateMachine::configuration() const
{
    Q_D(const QStateMachine);
    return d->configuration;
}

bool QStateMachine::event(QEvent *e)
{
    Q_D(QStateMachine);
    if (e->type() == QEvent::Timer) {
        QTimerEvent *te = static_cast<QTimerEvent*>(e);
        int tid = te->timerId();
        if (d->state != QStateMachinePrivate::Running) {
            // This event has been cancelled already
            QMutexLocker locker(&d->delayedEventsMutex);
            Q_ASSERT(!d->delayedEvents.contains(tid));
            return true;
        }
        d->delayedEventsMutex.lock();
        QEvent *ee = d->delayedEvents.take(tid);
        if (ee != 0) {
            killTimer(tid);
            d->delayedEventsMutex.unlock();
            d->postExternalEvent(ee);
            d->processEvents(QStateMachinePrivate::DirectProcessing);
            return true;
        } else {
            d->delayedEventsMutex.unlock();
        }
    }
    return QState::event(e);
}

#ifndef QT_NO_STATEMACHINE_EVENTFILTER

bool QStateMachine::eventFilter(QObject *watched, QEvent *event)
{
    Q_D(QStateMachine);
    d->handleFilteredEvent(watched, event);
    return false;
}
#endif

void QStateMachine::beginSelectTransitions(QEvent *event)
{
    Q_UNUSED(event);
}

void QStateMachine::endSelectTransitions(QEvent *event)
{
    Q_UNUSED(event);
}

void QStateMachine::beginMicrostep(QEvent *event)
{
    Q_UNUSED(event);
}

void QStateMachine::endMicrostep(QEvent *event)
{
    Q_UNUSED(event);
}

void QStateMachine::onEntry(QEvent *event)
{
    start();
    QState::onEntry(event);
}

void QStateMachine::onExit(QEvent *event)
{
    stop();
    QState::onExit(event);
}

#ifndef QT_NO_ANIMATION

bool QStateMachine::isAnimated() const
{
    Q_D(const QStateMachine);
    return d->animated;
}

void QStateMachine::setAnimated(bool enabled)
{
    Q_D(QStateMachine);
    d->animated = enabled;
}

void QStateMachine::addDefaultAnimation(QAbstractAnimation *animation)
{
    Q_D(QStateMachine);
    d->defaultAnimations.append(animation);
}

QList<QAbstractAnimation*> QStateMachine::defaultAnimations() const
{
    Q_D(const QStateMachine);
    return d->defaultAnimations;
}

void QStateMachine::removeDefaultAnimation(QAbstractAnimation *animation)
{
    Q_D(QStateMachine);
    d->defaultAnimations.removeAll(animation);
}

#endif // QT_NO_ANIMATION


static const uint qt_meta_data_QSignalEventGenerator[] = {

 // content:
       2,       // revision
       0,       // classname
       0,    0, // classinfo
       1,   12, // methods
       0,    0, // properties
       0,    0, // enums/sets
       0,    0, // constructors

 // slots: signature, parameters, type, tag, flags
      23,   22,   22,   22, 0x0a,

       0        // eod
};

static const char qt_meta_stringdata_QSignalEventGenerator[] = {
    "QSignalEventGenerator\0\0execute()\0"
};

const QMetaObject QSignalEventGenerator::staticMetaObject = {
    { &QObject::staticMetaObject, qt_meta_stringdata_QSignalEventGenerator,
      qt_meta_data_QSignalEventGenerator, 0 }
};

const QMetaObject *QSignalEventGenerator::metaObject() const
{
    return &staticMetaObject;
}

void *QSignalEventGenerator::qt_metacast(const char *_clname)
{
    if (!_clname) return 0;
    if (!strcmp(_clname, qt_meta_stringdata_QSignalEventGenerator))
        return static_cast<void*>(const_cast< QSignalEventGenerator*>(this));
    return QObject::qt_metacast(_clname);
}

int QSignalEventGenerator::qt_metacall(QMetaObject::Call _c, int _id, void **_a)
{
    _id = QObject::qt_metacall(_c, _id, _a);
    if (_id < 0)
        return _id;
    if (_c == QMetaObject::InvokeMetaMethod) {
        switch (_id) {
        case 0: {
// ### in Qt 4.6 we can use QObject::senderSignalIndex()
            QObjectPrivate *d = static_cast<QObjectPrivate *>(d_ptr.data());
            int signalIndex = -1;
            QObject *sender = this->sender();
            if (sender && d->currentSender)
                signalIndex = d->currentSender->signal;

            Q_ASSERT(signalIndex != -1);
            QStateMachine *machine = qobject_cast<QStateMachine*>(parent());
            QStateMachinePrivate::get(machine)->handleTransitionSignal(sender, signalIndex, _a);
            break;
        }
        default: ;
        }
        _id -= 1;
    }
    return _id;
}

QSignalEventGenerator::QSignalEventGenerator(QStateMachine *parent)
    : QObject(parent)
{
}

QStateMachine::SignalEvent::SignalEvent(QObject *sender, int signalIndex,
                                        const QList<QVariant> &arguments)
    : QEvent(QEvent::StateMachineSignal), m_sender(sender),
      m_signalIndex(signalIndex), m_arguments(arguments)
{
}

QStateMachine::SignalEvent::~SignalEvent()
{
}

QStateMachine::WrappedEvent::WrappedEvent(QObject *object, QEvent *event)
    : QEvent(QEvent::StateMachineWrapped), m_object(object), m_event(event)
{
}

QStateMachine::WrappedEvent::~WrappedEvent()
{
    delete m_event;
}

QT_END_NAMESPACE

#include "moc_qstatemachine.cpp"

#endif //QT_NO_STATEMACHINE