qtbase/src/corelib/statemachine/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

/*!
    \class QStateMachine
    \reentrant

    \brief The QStateMachine class provides a hierarchical finite state machine.

    \since 4.6
    \ingroup statemachine

    QStateMachine is based on the concepts and notation of
    \l{Statecharts: A visual formalism for complex
    systems}{Statecharts}. QStateMachine is part of \l{The State
    Machine Framework}.

    A state machine manages a set of states (classes that inherit from
    QAbstractState) and transitions (descendants of
    QAbstractTransition) between those states; these states and
    transitions define a state graph. Once a state graph has been
    built, the state machine can execute it. QStateMachine's
    execution algorithm is based on the \l{State Chart XML: State
    Machine Notation for Control Abstraction}{State Chart XML (SCXML)}
    algorithm. The framework's \l{The State Machine
    Framework}{overview} gives several state graphs and the code to
    build them.

    Use the addState() function to add a top-level state to the state machine.
    States are removed with the removeState() function. Removing states while
    the machine is running is discouraged.

    Before the machine can be started, the \l{initialState}{initial
    state} must be set. The initial state is the state that the
    machine enters when started. You can then start() the state
    machine. The started() signal is emitted when the initial state is
    entered.

    The machine is event driven and keeps its own event loop. Events
    are posted to the machine through postEvent(). Note that this
    means that it executes asynchronously, and that it will not
    progress without a running event loop. You will normally not have
    to post events to the machine directly as Qt's transitions, e.g.,
    QEventTransition and its subclasses, handle this. But for custom
    transitions triggered by events, postEvent() is useful.

    The state machine processes events and takes transitions until a
    top-level final state is entered; the state machine then emits the
    finished() signal. You can also stop() the state machine
    explicitly. The stopped() signal is emitted in this case.

    The following snippet shows a state machine that will finish when a button
    is clicked:

    \snippet code/src_corelib_statemachine_qstatemachine.cpp simple state machine

    This code example uses QState, which inherits QAbstractState. The
    QState class provides a state that you can use to set properties
    and invoke methods on \l{QObject}s when the state is entered or
    exited. It also contains convenience functions for adding
    transitions, e.g., \l{QSignalTransition}s as in this example. See
    the QState class description for further details.

    If an error is encountered, the machine will look for an
    \l{errorState}{error state}, and if one is available, it will
    enter this state. The types of errors possible are described by the
    \l{QStateMachine::}{Error} enum. After the error state is entered,
    the type of the error can be retrieved with error(). The execution
    of the state graph will not stop when the error state is entered. If 
    no error state applies to the erroneous state, the machine will stop 
    executing and an error message will be printed to the console.

    \sa QAbstractState, QAbstractTransition, QState, {The State Machine Framework}
*/

/*!
    \property QStateMachine::errorString

    \brief the error string of this state machine
*/

/*!
    \property QStateMachine::globalRestorePolicy

    \brief the restore policy for states of this state machine.

    The default value of this property is
    QStateMachine::DontRestoreProperties.
*/

#ifndef QT_NO_ANIMATION
/*!
    \property QStateMachine::animated

    \brief whether animations are enabled

    The default value of this property is true.

    \sa QAbstractTransition::addAnimation()
*/
#endif

// #define QSTATEMACHINE_DEBUG
// #define QSTATEMACHINE_RESTORE_PROPERTIES_DEBUG

template <class T>
static uint qHash(const QPointer<T> &p)
{ return qHash(p.data()); }

QStateMachinePrivate::QStateMachinePrivate()
{
    isMachine = true;

    state = NotRunning;
    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->parent()->children().indexOf(s1)
            < s2->parent()->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->parent()->children().indexOf(s1)
            < s2->parent()->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 = computeStatesToExit(enabledTransitions);
    QHash<RestorableId, QVariant> pendingRestorables = computePendingRestorables(exitedStates);

    QSet<QAbstractState*> statesForDefaultEntry;
    QList<QAbstractState*> enteredStates = computeStatesToEnter(enabledTransitions, statesForDefaultEntry);

    QHash<QAbstractState*, QList<QPropertyAssignment> > assignmentsForEnteredStates =
            computePropertyAssignments(enteredStates, pendingRestorables);
    if (!pendingRestorables.isEmpty()) {
        // Add "implicit" assignments for restored properties to the first
        // (outermost) entered state
        Q_ASSERT(!enteredStates.isEmpty());
        QAbstractState *s = enteredStates.first();
        assignmentsForEnteredStates[s] << restorablesToPropertyList(pendingRestorables);
    }

    exitStates(event, exitedStates, assignmentsForEnteredStates);
#ifdef QSTATEMACHINE_DEBUG
    qDebug() << q_func() << ": configuration after exiting states:" << configuration;
#endif

    executeTransitionContent(event, enabledTransitions);

#ifndef QT_NO_ANIMATION
    QList<QAbstractAnimation *> selectedAnimations = selectAnimations(enabledTransitions);
#endif

    enterStates(event, exitedStates, enteredStates, statesForDefaultEntry, assignmentsForEnteredStates
#ifndef QT_NO_ANIMATION
                , selectedAnimations
#endif
                );
#ifdef QSTATEMACHINE_DEBUG
    qDebug() << q_func() << ": configuration after entering states:" << configuration;
    qDebug() << q_func() << ": end microstep";
#endif
}

QList<QAbstractState*> QStateMachinePrivate::computeStatesToExit(const QList<QAbstractTransition*> &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);
    return statesToExit_sorted;
}

void QStateMachinePrivate::exitStates(QEvent *event, const QList<QAbstractState*> &statesToExit_sorted,
                                      const QHash<QAbstractState*, QList<QPropertyAssignment> > &assignmentsForEnteredStates)
{
    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);

#ifndef QT_NO_ANIMATION
        terminateActiveAnimations(s, assignmentsForEnteredStates);
#else
        Q_UNUSED(assignmentsForEnteredStates);
#endif

        configuration.remove(s);
        QAbstractStatePrivate::get(s)->emitExited();
    }
}

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::computeStatesToEnter(const QList<QAbstractTransition *> &enabledTransitions,
                                                                  QSet<QAbstractState *> &statesForDefaultEntry)
{
    QSet<QAbstractState*> statesToEnter;
    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;
            QAbstractState *src = t->sourceState();
            if (src)
                lst.prepend(src);
            QState *lca = findLCA(lst);
            for (int j = src ? 1 : 0; j < lst.size(); ++j) {
                QAbstractState *s = lst.at(j);
                addStatesToEnter(s, lca, statesToEnter, statesForDefaultEntry);
            }
            for (int j = src ? 1 : 0; j < lst.size(); ++j) {
                QAbstractState *s = lst.at(j);
                addAncestorStatesToEnter(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);
    return statesToEnter_sorted;
}

void QStateMachinePrivate::enterStates(QEvent *event, const QList<QAbstractState*> &exitedStates_sorted,
                                       const QList<QAbstractState*> &statesToEnter_sorted,
                                       const QSet<QAbstractState*> &statesForDefaultEntry,
                                       QHash<QAbstractState*, QList<QPropertyAssignment> > &propertyAssignmentsForState
#ifndef QT_NO_ANIMATION
                                       , const QList<QAbstractAnimation *> &selectedAnimations
#endif
                                       )
{
#ifdef QSTATEMACHINE_DEBUG
    Q_Q(QStateMachine);
#endif
    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);

#ifndef QT_NO_ANIMATION
        initializeAnimations(s, selectedAnimations, exitedStates_sorted, propertyAssignmentsForState);
#endif

        // Immediately set the properties that are not animated.
        {
            QList<QPropertyAssignment> assignments = propertyAssignmentsForState.value(s);
            for (int i = 0; i < assignments.size(); ++i) {
                const QPropertyAssignment &assn = assignments.at(i);
                if (globalRestorePolicy == QStateMachine::RestoreProperties) {
                    if (assn.explicitlySet) {
                        if (!hasRestorable(s, assn.object, assn.propertyName)) {
                            QVariant value = savedValueForRestorable(exitedStates_sorted, assn.object, assn.propertyName);
                            unregisterRestorables(exitedStates_sorted, assn.object, assn.propertyName);
                            registerRestorable(s, assn.object, assn.propertyName, value);
                        }
                    } else {
                        // The property is being restored, hence no need to
                        // save the current value. Discard any saved values in
                        // exited states, since those are now stale.
                        unregisterRestorables(exitedStates_sorted, assn.object, assn.propertyName);
                    }
                }
                assn.write();
            }
        }

        QAbstractStatePrivate::get(s)->callOnEntry(event);
        QAbstractStatePrivate::get(s)->emitEntered();
        if (statesForDefaultEntry.contains(s)) {
            // ### executeContent(s.initial.transition.children())
        }

        // Emit propertiesAssigned signal if the state has no animated properties.
        {
            QState *ss = toStandardState(s);
            if (ss
    #ifndef QT_NO_ANIMATION
                && !animationsForState.contains(s)
    #endif
                )
                QStatePrivate::get(ss)->emitPropertiesAssigned();
        }

        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)) {
                QState *parent = (*it)->parentState();
                if (((parent == rootState())
                     && (rootState()->childMode() == QState::ExclusiveStates))
                    || ((parent->parentState() == rootState())
                        && (rootState()->childMode() == QState::ParallelStates)
                        && isInFinalState(rootState()))) {
                    processing = false;
                    stopProcessingReason = Finished;
                    break;
                }
            }
        }
    }
//    qDebug() << "configuration:" << configuration.toList();
}

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;
			}
		}
	}
}

void QStateMachinePrivate::addAncestorStatesToEnter(QAbstractState *s, QState *root,
                                                    QSet<QAbstractState*> &statesToEnter,
                                                    QSet<QAbstractState*> &statesForDefaultEntry)
{
    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);
            }
        }
    }
}

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());
}

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

/*!
  \internal
  Returns true if the given state has saved the value of the given property,
  otherwise returns false.
*/
bool QStateMachinePrivate::hasRestorable(QAbstractState *state, QObject *object,
                                         const QByteArray &propertyName) const
{
    RestorableId id(object, propertyName);
    return registeredRestorablesForState.value(state).contains(id);
}

/*!
  \internal
  Returns the value to save for the property identified by \a id.
  If an exited state (member of \a exitedStates_sorted) has saved a value for
  the property, the saved value from the last (outermost) state that will be
  exited is returned (in practice carrying the saved value on to the next
  state). Otherwise, the current value of the property is returned.
*/
QVariant QStateMachinePrivate::savedValueForRestorable(const QList<QAbstractState*> &exitedStates_sorted,
                                                       QObject *object, const QByteArray &propertyName) const
{
#ifdef QSTATEMACHINE_RESTORE_PROPERTIES_DEBUG
    qDebug() << q_func() << ": savedValueForRestorable(" << exitedStates_sorted << object << propertyName << ")";
#endif
    RestorableId id(object, propertyName);
    for (int i = exitedStates_sorted.size() - 1; i >= 0; --i) {
        QAbstractState *s = exitedStates_sorted.at(i);
        QHash<RestorableId, QVariant> restorables = registeredRestorablesForState.value(s);
        QHash<RestorableId, QVariant>::const_iterator it = restorables.constFind(id);
        if (it != restorables.constEnd()) {
#ifdef QSTATEMACHINE_RESTORE_PROPERTIES_DEBUG
            qDebug() << q_func() << ":   using" << it.value() << "from" << s;
#endif
            return it.value();
        }
    }
#ifdef QSTATEMACHINE_RESTORE_PROPERTIES_DEBUG
    qDebug() << q_func() << ":   falling back to current value";
#endif
    return id.first->property(id.second);
}

void QStateMachinePrivate::registerRestorable(QAbstractState *state, QObject *object, const QByteArray &propertyName,
                                              const QVariant &value)
{
#ifdef QSTATEMACHINE_RESTORE_PROPERTIES_DEBUG
    qDebug() << q_func() << ": registerRestorable(" << state << object << propertyName << value << ")";
#endif
    RestorableId id(object, propertyName);
    QHash<RestorableId, QVariant> &restorables = registeredRestorablesForState[state];
    if (!restorables.contains(id))
        restorables.insert(id, value);
#ifdef QSTATEMACHINE_RESTORE_PROPERTIES_DEBUG
    else
        qDebug() << q_func() << ":   (already registered)";
#endif
}

void QStateMachinePrivate::unregisterRestorables(const QList<QAbstractState *> &states, QObject *object,
                                                 const QByteArray &propertyName)
{
#ifdef QSTATEMACHINE_RESTORE_PROPERTIES_DEBUG
    qDebug() << q_func() << ": unregisterRestorables(" << states << object << propertyName << ")";
#endif
    RestorableId id(object, propertyName);
    for (int i = 0; i < states.size(); ++i) {
        QAbstractState *s = states.at(i);
        QHash<QAbstractState*, QHash<RestorableId, QVariant> >::iterator it;
        it = registeredRestorablesForState.find(s);
        if (it == registeredRestorablesForState.end())
            continue;
        QHash<RestorableId, QVariant> &restorables = it.value();
        QHash<RestorableId, QVariant>::iterator it2;
        it2 = restorables.find(id);
        if (it2 == restorables.end())
            continue;
#ifdef QSTATEMACHINE_RESTORE_PROPERTIES_DEBUG
        qDebug() << q_func() << ":   unregistered for" << s;
#endif
        restorables.erase(it2);
        if (restorables.isEmpty())
            registeredRestorablesForState.erase(it);
    }
}

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) {
        if (!it.key().first) {
            // Property object was deleted
            continue;
        }
#ifdef QSTATEMACHINE_RESTORE_PROPERTIES_DEBUG
        qDebug() << q_func() << ": restoring" << it.key().first << it.key().second << "to" << it.value();
#endif
        result.append(QPropertyAssignment(it.key().first, it.key().second, it.value(), /*explicitlySet=*/false));
    }
    return result;
}

/*!
  \internal
  Computes the set of properties whose values should be restored given that
  the states \a statesToExit_sorted will be exited.

  If a particular (object, propertyName) pair occurs more than once (i.e.,
  because nested states are being exited), the value from the last (outermost)
  exited state takes precedence.

  The result of this function must be filtered according to the explicit
  property assignments (QState::assignProperty()) of the entered states
  before the property restoration is actually performed; i.e., if an entered
  state assigns to a property that would otherwise be restored, that property
  should not be restored after all, but the saved value from the exited state
  should be remembered by the entered state (see registerRestorable()).
*/
QHash<QStateMachinePrivate::RestorableId, QVariant> QStateMachinePrivate::computePendingRestorables(
        const QList<QAbstractState*> &statesToExit_sorted) const
{
    QHash<QStateMachinePrivate::RestorableId, QVariant> restorables;
    for (int i = statesToExit_sorted.size() - 1; i >= 0; --i) {
        QAbstractState *s = statesToExit_sorted.at(i);
        QHash<QStateMachinePrivate::RestorableId, QVariant> rs = registeredRestorablesForState.value(s);
        QHash<QStateMachinePrivate::RestorableId, QVariant>::const_iterator it;
        for (it = rs.constBegin(); it != rs.constEnd(); ++it) {
            if (!restorables.contains(it.key()))
                restorables.insert(it.key(), it.value());
        }
    }
    return restorables;
}

/*!
  \internal
  Computes the ordered sets of property assignments for the states to be
  entered, \a statesToEnter_sorted. Also filters \a pendingRestorables (removes
  properties that should not be restored because they are assigned by an
  entered state).
*/
QHash<QAbstractState*, QList<QPropertyAssignment> > QStateMachinePrivate::computePropertyAssignments(
        const QList<QAbstractState*> &statesToEnter_sorted, QHash<RestorableId, QVariant> &pendingRestorables) const
{
    QHash<QAbstractState*, QList<QPropertyAssignment> > assignmentsForState;
    for (int i = 0; i < statesToEnter_sorted.size(); ++i) {
        QState *s = toStandardState(statesToEnter_sorted.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 (assn.objectDeleted()) {
                assignments.removeAt(j--);
            } else {
                pendingRestorables.remove(RestorableId(assn.object, assn.propertyName));
                assignmentsForState[s].append(assn);
            }
        }
    }
    return assignmentsForState;
}

#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);
        addAncestorStatesToEnter(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);
    }

    QAbstractState *state = stateForAnimation.take(anim);
    Q_ASSERT(state != 0);

#ifndef QT_NO_PROPERTIES
    // Set the final property value.
    QPropertyAssignment assn = propertyForAnimation.take(anim);
    assn.write();
    if (!assn.explicitlySet)
        unregisterRestorables(QList<QAbstractState*>() << state, assn.object, assn.propertyName);
#endif

    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();
    }
}

QList<QAbstractAnimation *> QStateMachinePrivate::selectAnimations(const QList<QAbstractTransition *> &transitionList) const
{
    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;
    }
    return selectedAnimations;
}

void QStateMachinePrivate::terminateActiveAnimations(QAbstractState *state,
    const QHash<QAbstractState*, QList<QPropertyAssignment> > &assignmentsForEnteredStates)
{
    Q_Q(QStateMachine);
    QList<QAbstractAnimation*> animations = animationsForState.take(state);
    for (int i = 0; i < animations.size(); ++i) {
        QAbstractAnimation *anim = animations.at(i);
        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 = assignmentsForEnteredStates.constBegin(); it != assignmentsForEnteredStates.constEnd(); ++it) {
            const QList<QPropertyAssignment> &assignments = it.value();
            for (int j = 0; j < assignments.size(); ++j) {
                if (assignments.at(j).hasTarget(assn.object, assn.propertyName)) {
                    found = true;
                    break;
                }
            }
        }
        if (!found) {
            assn.write();
            if (!assn.explicitlySet)
                unregisterRestorables(QList<QAbstractState*>() << state, assn.object, assn.propertyName);
        }
    }
}

void QStateMachinePrivate::initializeAnimations(QAbstractState *state, const QList<QAbstractAnimation *> &selectedAnimations,
                                                const QList<QAbstractState*> &exitedStates_sorted,
                                                QHash<QAbstractState*, QList<QPropertyAssignment> > &assignmentsForEnteredStates)
{
    Q_Q(QStateMachine);
    if (!assignmentsForEnteredStates.contains(state))
        return;
    QList<QPropertyAssignment> &assignments = assignmentsForEnteredStates[state];
    for (int i = 0; i < selectedAnimations.size(); ++i) {
        QAbstractAnimation *anim = selectedAnimations.at(i);
        QList<QPropertyAssignment>::iterator it;
        for (it = assignments.begin(); it != assignments.end(); ) {
            QPair<QList<QAbstractAnimation*>, QList<QAbstractAnimation*> > ret;
            const QPropertyAssignment &assn = *it;
            ret = initializeAnimation(anim, assn);
            QList<QAbstractAnimation*> handlers = ret.first;
            if (!handlers.isEmpty()) {
                for (int j = 0; j < handlers.size(); ++j) {
                    QAbstractAnimation *a = handlers.at(j);
                    propertyForAnimation.insert(a, assn);
                    stateForAnimation.insert(a, state);
                    animationsForState[state].append(a);
                    // ### connect to just the top-level animation?
                    QObject::connect(a, SIGNAL(finished()), q, SLOT(_q_animationFinished()), Qt::UniqueConnection);
                }
                if ((globalRestorePolicy == QStateMachine::RestoreProperties)
                        && !hasRestorable(state, assn.object, assn.propertyName)) {
                    QVariant value = savedValueForRestorable(exitedStates_sorted, assn.object, assn.propertyName);
                    unregisterRestorables(exitedStates_sorted, assn.object, assn.propertyName);
                    registerRestorable(state, assn.object, assn.propertyName, value);
                }
                it = assignments.erase(it);
            } else {
                ++it;
            }
            for (int j = 0; j < ret.second.size(); ++j)
                resetAnimationEndValues.insert(ret.second.at(j));
        }
        // 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();
        }

        if (assignments.isEmpty()) {
            assignmentsForEnteredStates.remove(state);
            break;
        }
    }
}

#endif // !QT_NO_ANIMATION

QAbstractTransition *QStateMachinePrivate::createInitialTransition() const
{
    class InitialTransition : public QAbstractTransition
    {
    public:
        InitialTransition(const QList<QAbstractState *> &targets)
            : QAbstractTransition()
        { setTargetStates(targets); }
    protected:
        virtual bool eventTest(QEvent *) { return true; }
        virtual void onTransition(QEvent *) {}
    };

    QState *root = rootState();
    Q_ASSERT(root != 0);
    QList<QAbstractState *> targets;
    switch (root->childMode()) {
    case QState::ExclusiveStates:
        targets.append(root->initialState());
        break;
    case QState::ParallelStates:
        targets = QStatePrivate::get(root)->childStates();
        break;
    }
    return new InitialTransition(targets);
}

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);
    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

    QList<QAbstractTransition*> transitions;
    QAbstractTransition *initialTransition = createInitialTransition();
    transitions.append(initialTransition);

    QEvent nullEvent(QEvent::None);
    executeTransitionContent(&nullEvent, transitions);
    QList<QAbstractState*> exitedStates = QList<QAbstractState*>();
    QSet<QAbstractState*> statesForDefaultEntry;
    QList<QAbstractState*> enteredStates = computeStatesToEnter(transitions,
                                                                statesForDefaultEntry);
    QHash<RestorableId, QVariant> pendingRestorables;
    QHash<QAbstractState*, QList<QPropertyAssignment> > assignmentsForEnteredStates =
            computePropertyAssignments(enteredStates, pendingRestorables);
#ifndef QT_NO_ANIMATION
    QList<QAbstractAnimation*> selectedAnimations = selectAnimations(transitions);
#endif
    // enterStates() will set stopProcessingReason to Finished if a final
    // state is entered.
    stopProcessingReason = EventQueueEmpty;
    enterStates(&nullEvent, exitedStates, enteredStates, statesForDefaultEntry,
                assignmentsForEnteredStates
#ifndef QT_NO_ANIMATION
                , selectedAnimations
#endif
                );
    delete initialTransition;

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

    emit q->started();

    if (stopProcessingReason == Finished) {
        // The state machine immediately reached a final state.
        processingScheduled = false;
        state = NotRunning;
        unregisterAllTransitions();
        emit q->finished();
    } else {
        _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::_q_startDelayedEventTimer(int id, int delay)
{
    Q_Q(QStateMachine);
    QMutexLocker locker(&delayedEventsMutex);
    QHash<int, DelayedEvent>::iterator it = delayedEvents.find(id);
    if (it != delayedEvents.end()) {
        DelayedEvent &e = it.value();
        Q_ASSERT(!e.timerId);
        e.timerId = q->startTimer(delay);
        if (!e.timerId) {
            qWarning("QStateMachine::postDelayedEvent: failed to start timer (id=%d, delay=%d)", id, delay);
            delayedEvents.erase(it);
            delayedEventIdFreeList.release(id);
        } else {
            timerIdToDelayedEventId.insert(e.timerId, id);
        }
    } else {
        // It's been cancelled already
        delayedEventIdFreeList.release(id);
    }
}

void QStateMachinePrivate::_q_killDelayedEventTimer(int id, int timerId)
{
    Q_Q(QStateMachine);
    q->killTimer(timerId);
    QMutexLocker locker(&delayedEventsMutex);
    delayedEventIdFreeList.release(id);
}

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, DelayedEvent>::const_iterator it;
    for (it = delayedEvents.constBegin(); it != delayedEvents.constEnd(); ++it) {
        const DelayedEvent &e = it.value();
        if (e.timerId) {
            timerIdToDelayedEventId.remove(e.timerId);
            q->killTimer(e.timerId);
            delayedEventIdFreeList.release(it.key());
        } else {
            // Cancellation will be detected in pending _q_startDelayedEventTimer() call
        }
        delete e.event;
    }
    delayedEvents.clear();
}

namespace _QStateMachine_Internal{

class GoToStateTransition : public QAbstractTransition
{
    Q_OBJECT
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;
/*!
  \internal

  Causes this state machine to unconditionally transition to the given
  \a targetState.

  Provides a backdoor for using the state machine "imperatively"; i.e.  rather
  than defining explicit transitions, you drive the machine's execution by
  calling this function. It breaks the whole integrity of the
  transition-driven model, but is provided for pragmatic reasons.
*/
void QStateMachinePrivate::goToState(QAbstractState *targetState)
{
    if (!targetState) {
        qWarning("QStateMachine::goToState(): cannot go to null state");
        return;
    }

    if (configuration.contains(targetState))
        return;

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

    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);
        registerTransition(t);
    }
}

void QStateMachinePrivate::maybeRegisterTransition(QAbstractTransition *transition)
{
    if (QSignalTransition *st = qobject_cast<QSignalTransition*>(transition)) {
        maybeRegisterSignalTransition(st);
    }
#ifndef QT_NO_STATEMACHINE_EVENTFILTER
    else if (QEventTransition *et = qobject_cast<QEventTransition*>(transition)) {
        maybeRegisterEventTransition(et);
    }
#endif
}

void QStateMachinePrivate::registerTransition(QAbstractTransition *transition)
{
    if (QSignalTransition *st = qobject_cast<QSignalTransition*>(transition)) {
        registerSignalTransition(st);
    }
#ifndef QT_NO_STATEMACHINE_EVENTFILTER
    else if (QEventTransition *oet = qobject_cast<QEventTransition*>(transition)) {
        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::maybeRegisterSignalTransition(QSignalTransition *transition)
{
    Q_Q(QStateMachine);
    if (((state == Running) && configuration.contains(transition->sourceState()))
            || (transition->senderObject() && (transition->senderObject()->thread() != q->thread()))) {
        registerSignalTransition(transition);
    }
}

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.isEmpty())
        return;
    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;
        }
        originalSignalIndex = signalIndex;
    }
    // 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;

    connectionsMutex.lock();
    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];
    connectionsMutex.unlock();

    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)
{
    Q_Q(QStateMachine);
    int signalIndex = QSignalTransitionPrivate::get(transition)->signalIndex;
    if (signalIndex == -1)
        return; // not registered
    const QObject *sender = QSignalTransitionPrivate::get(transition)->sender;
    // Don't unregister if the sender is on another thread
    if (!sender || (sender->thread() != q->thread()))
        return;
    QSignalTransitionPrivate::get(transition)->signalIndex = -1;

    connectionsMutex.lock();
    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);
    }
    connectionsMutex.unlock();
}

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::maybeRegisterEventTransition(QEventTransition *transition)
{
    if ((state == Running) && configuration.contains(transition->sourceState()))
        registerEventTransition(transition);
}

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->extraData || !od->extraData->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)
{
#ifndef QT_NO_DEBUG
    connectionsMutex.lock();
    Q_ASSERT(connections[sender].at(signalIndex) != 0);
    connectionsMutex.unlock();
#endif
    const QMetaObject *meta = sender->metaObject();
    QMetaMethod method = meta->method(signalIndex);
    int argc = method.parameterCount();
    QList<QVariant> vargs;
    for (int i = 0; i < argc; ++i) {
        int type = method.parameterType(i);
        vargs.append(QVariant(type, argv[i+1]));
    }

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

/*!
  Constructs a new state machine with the given \a parent.
*/
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);
}

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

/*!
  Destroys this state machine.
*/
QStateMachine::~QStateMachine()
{
}

/*!
  \enum QStateMachine::EventPriority

  This enum type specifies the priority of an event posted to the state
  machine using postEvent().

  Events of high priority are processed before events of normal priority.

  \value NormalPriority The event has normal priority.
  \value HighPriority The event has high priority.
*/

/*! \enum QStateMachine::Error 

    This enum type defines errors that can occur in the state machine at run time. When the state
    machine encounters an unrecoverable error at run time, it will set the error code returned 
    by error(), the error message returned by errorString(), and enter an error state based on 
    the context of the error.

    \value NoError No error has occurred.
    \value NoInitialStateError The machine has entered a QState with children which does not have an
           initial state set. The context of this error is the state which is missing an initial
           state.
    \value NoDefaultStateInHistoryStateError The machine has entered a QHistoryState which does not have 
           a default state set. The context of this error is the QHistoryState which is missing a
           default state.
    \value NoCommonAncestorForTransitionError The machine has selected a transition whose source 
           and targets are not part of the same tree of states, and thus are not part of the same 
           state machine. Commonly, this could mean that one of the states has not been given 
           any parent or added to any machine. The context of this error is the source state of 
           the transition.

    \sa setErrorState()
*/

/*!
   \enum QStateMachine::RestorePolicy

   This enum specifies the restore policy type. The restore policy
   takes effect when the machine enters a state which sets one or more
   properties. If the restore policy is set to RestoreProperties,
   the state machine will save the original value of the property before the
   new value is set.

   Later, when the machine either enters a state which does not set
   a value for the given property, the property will automatically be restored
   to its initial value.

   Only one initial value will be saved for any given property. If a value for a property has 
   already been saved by the state machine, it will not be overwritten until the property has been
   successfully restored. 

   \value DontRestoreProperties The state machine should not save the initial values of properties
          and restore them later.
   \value RestoreProperties The state machine should save the initial values of properties 
          and restore them later.

   \sa QStateMachine::globalRestorePolicy, QState::assignProperty()
*/


/*!
  Returns the error code of the last error that occurred in the state machine.
*/
QStateMachine::Error QStateMachine::error() const
{
    Q_D(const QStateMachine);
    return d->error;
}

/*!
  Returns the error string of the last error that occurred in the state machine.
*/
QString QStateMachine::errorString() const
{
    Q_D(const QStateMachine);
    return d->errorString;
}

/*!
  Clears the error string and error code of the state machine.
*/
void QStateMachine::clearError()
{
    Q_D(QStateMachine);
    d->errorString.clear();
    d->error = NoError;
}

/*!
   Returns the restore policy of the state machine.

   \sa setGlobalRestorePolicy()
*/
QStateMachine::RestorePolicy QStateMachine::globalRestorePolicy() const
{
    Q_D(const QStateMachine);
    return d->globalRestorePolicy;
}

/*!
   Sets the restore policy of the state machine to \a restorePolicy. The default 
   restore policy is QAbstractState::DontRestoreProperties.
   
   \sa globalRestorePolicy()
*/
void QStateMachine::setGlobalRestorePolicy(QStateMachine::RestorePolicy restorePolicy) 
{
    Q_D(QStateMachine);
    d->globalRestorePolicy = restorePolicy;
}

/*!
  Adds the given \a state to this state machine. The state becomes a top-level
  state.

  If the state is already in a different machine, it will first be removed
  from its old machine, and then added to this machine.

  \sa removeState(), setInitialState()
*/
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);
}

/*!
  Removes the given \a state from this state machine.  The state machine
  releases ownership of the state.

  \sa addState()
*/
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);
}

/*!
  Returns whether this state machine is running.

  \sa start(), stop()
*/
bool QStateMachine::isRunning() const
{
    Q_D(const QStateMachine);
    return (d->state == QStateMachinePrivate::Running);
}

/*!
  Starts this state machine.  The machine will reset its configuration and
  transition to the initial state.  When a final top-level state (QFinalState)
  is entered, the machine will emit the finished() signal.

  \note A state machine will not run without a running event loop, such as
  the main application event loop started with QCoreApplication::exec() or
  QApplication::exec().

  \sa started(), finished(), stop(), initialState()
*/
void QStateMachine::start()
{
    Q_D(QStateMachine);

    if ((childMode() == QState::ExclusiveStates) && (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;
    }
}

/*!
  Stops this state machine. The state machine will stop processing events and
  then emit the stopped() signal.

  \sa stopped(), start()
*/
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;
    }
}

/*!
  \threadsafe

  Posts the given \a event of the given \a priority for processing by this
  state machine.

  This function returns immediately. The event is added to the state machine's
  event queue. Events are processed in the order posted. The state machine
  takes ownership of the event and deletes it once it has been processed.

  You can only post events when the state machine is running.

  \sa postDelayedEvent()
*/
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);
}

/*!
  \threadsafe

  Posts the given \a event for processing by this state machine, with the
  given \a delay in milliseconds. Returns an identifier associated with the
  delayed event, or -1 if the event could not be posted.

  This function returns immediately. When the delay has expired, the event
  will be added to the state machine's event queue for processing. The state
  machine takes ownership of the event and deletes it once it has been
  processed.

  You can only post events when the state machine is running.

  \sa cancelDelayedEvent(), postEvent()
*/
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 id = d->delayedEventIdFreeList.next();
    bool inMachineThread = (QThread::currentThread() == thread());
    int timerId = inMachineThread ? startTimer(delay) : 0;
    if (inMachineThread && !timerId) {
        qWarning("QStateMachine::postDelayedEvent: failed to start timer with interval %d", delay);
        d->delayedEventIdFreeList.release(id);
        return -1;
    }
    QStateMachinePrivate::DelayedEvent delayedEvent(event, timerId);
    d->delayedEvents.insert(id, delayedEvent);
    if (timerId) {
        d->timerIdToDelayedEventId.insert(timerId, id);
    } else {
        Q_ASSERT(!inMachineThread);
        QMetaObject::invokeMethod(this, "_q_startDelayedEventTimer",
                                  Qt::QueuedConnection,
                                  Q_ARG(int, id),
                                  Q_ARG(int, delay));
    }
    return id;
}

/*!
  \threadsafe

  Cancels the delayed event identified by the given \a id. The id should be a
  value returned by a call to postDelayedEvent(). Returns true if the event
  was successfully cancelled, otherwise returns false.

  \sa postDelayedEvent()
*/
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);
    QStateMachinePrivate::DelayedEvent e = d->delayedEvents.take(id);
    if (!e.event)
        return false;
    if (e.timerId) {
        d->timerIdToDelayedEventId.remove(e.timerId);
        bool inMachineThread = (QThread::currentThread() == thread());
        if (inMachineThread) {
            killTimer(e.timerId);
            d->delayedEventIdFreeList.release(id);
        } else {
            QMetaObject::invokeMethod(this, "_q_killDelayedEventTimer",
                                      Qt::QueuedConnection,
                                      Q_ARG(int, id),
                                      Q_ARG(int, e.timerId));
        }
    } else {
        // Cancellation will be detected in pending _q_startDelayedEventTimer() call
    }
    delete e.event;
    return true;
}

/*!
   Returns the maximal consistent set of states (including parallel and final
   states) that this state machine is currently in. If a state \c s is in the
   configuration, it is always the case that the parent of \c s is also in
   c. Note, however, that the machine itself is not an explicit member of the
   configuration.
*/
QSet<QAbstractState*> QStateMachine::configuration() const
{
    Q_D(const QStateMachine);
    return d->configuration;
}

/*!
  \fn QStateMachine::started()

  This signal is emitted when the state machine has entered its initial state
  (QStateMachine::initialState).

  \sa QStateMachine::finished(), QStateMachine::start()
*/

/*!
  \fn QStateMachine::stopped()

  This signal is emitted when the state machine has stopped.

  \sa QStateMachine::stop(), QStateMachine::finished()
*/

/*!
  \reimp
*/
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->timerIdToDelayedEventId.contains(tid));
            return true;
        }
        d->delayedEventsMutex.lock();
        int id = d->timerIdToDelayedEventId.take(tid);
        QStateMachinePrivate::DelayedEvent ee = d->delayedEvents.take(id);
        if (ee.event != 0) {
            Q_ASSERT(ee.timerId == tid);
            killTimer(tid);
            d->delayedEventIdFreeList.release(id);
            d->delayedEventsMutex.unlock();
            d->postExternalEvent(ee.event);
            d->processEvents(QStateMachinePrivate::DirectProcessing);
            return true;
        } else {
            d->delayedEventsMutex.unlock();
        }
    }
    return QState::event(e);
}

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

/*!
  \internal

  This function is called when the state machine is about to select
  transitions based on the given \a event.

  The default implementation does nothing.
*/
void QStateMachine::beginSelectTransitions(QEvent *event)
{
    Q_UNUSED(event);
}

/*!
  \internal

  This function is called when the state machine has finished selecting
  transitions based on the given \a event.

  The default implementation does nothing.
*/
void QStateMachine::endSelectTransitions(QEvent *event)
{
    Q_UNUSED(event);
}

/*!
  \internal

  This function is called when the state machine is about to do a microstep.

  The default implementation does nothing.
*/
void QStateMachine::beginMicrostep(QEvent *event)
{
    Q_UNUSED(event);
}

/*!
  \internal

  This function is called when the state machine has finished doing a
  microstep.

  The default implementation does nothing.
*/
void QStateMachine::endMicrostep(QEvent *event)
{
    Q_UNUSED(event);
}

/*!
  \reimp
    This function will call start() to start the state machine.
*/
void QStateMachine::onEntry(QEvent *event)
{
    start();
    QState::onEntry(event);
}

/*!
  \reimp
    This function will call stop() to stop the state machine and 
    subsequently emit the stopped() signal.
*/
void QStateMachine::onExit(QEvent *event)
{
    stop();
    QState::onExit(event);
}

#ifndef QT_NO_ANIMATION

/*!
  Returns whether animations are enabled for this state machine.
*/
bool QStateMachine::isAnimated() const
{
    Q_D(const QStateMachine);
    return d->animated;
}

/*!
  Sets whether animations are \a enabled for this state machine.
*/
void QStateMachine::setAnimated(bool enabled)
{
    Q_D(QStateMachine);
    d->animated = enabled;
}

/*!
    Adds a default \a animation to be considered for any transition.
*/    
void QStateMachine::addDefaultAnimation(QAbstractAnimation *animation)
{
    Q_D(QStateMachine);
    d->defaultAnimations.append(animation);
}

/*!
    Returns the list of default animations that will be considered for any transition.
*/
QList<QAbstractAnimation*> QStateMachine::defaultAnimations() const
{    
    Q_D(const QStateMachine);
    return d->defaultAnimations;
}

/*!
    Removes \a animation from the list of default animations. 
*/
void QStateMachine::removeDefaultAnimation(QAbstractAnimation *animation)
{
    Q_D(QStateMachine);
    d->defaultAnimations.removeAll(animation);
}

#endif // QT_NO_ANIMATION


// Begin moc-generated code -- modify carefully (check "HAND EDIT" parts)!
struct qt_meta_stringdata_QSignalEventGenerator_t {
    QByteArrayData data[3];
    char stringdata[32];
};
#define QT_MOC_LITERAL(idx, ofs, len) \
    Q_STATIC_BYTE_ARRAY_DATA_HEADER_INITIALIZER_WITH_OFFSET(len, \
        offsetof(qt_meta_stringdata_QSignalEventGenerator_t, stringdata) + ofs \
        - idx * sizeof(QByteArrayData) \
    )
static const qt_meta_stringdata_QSignalEventGenerator_t qt_meta_stringdata_QSignalEventGenerator = {
    {
QT_MOC_LITERAL(0, 0, 21),
QT_MOC_LITERAL(1, 22, 7),
QT_MOC_LITERAL(2, 30, 0)
    },
    "QSignalEventGenerator\0execute\0\0"
};
#undef QT_MOC_LITERAL

static const uint qt_meta_data_QSignalEventGenerator[] = {

 // content:
       7,       // revision
       0,       // classname
       0,    0, // classinfo
       1,   14, // methods
       0,    0, // properties
       0,    0, // enums/sets
       0,    0, // constructors
       0,       // flags
       0,       // signalCount

 // slots: name, argc, parameters, tag, flags
       1,    0,   19,    2, 0x0a,

 // slots: parameters
    QMetaType::Void,

       0        // eod
};

void QSignalEventGenerator::qt_static_metacall(QObject *_o, QMetaObject::Call _c, int _id, void **_a)
{
    if (_c == QMetaObject::InvokeMetaMethod) {
        Q_ASSERT(staticMetaObject.cast(_o));
        QSignalEventGenerator *_t = static_cast<QSignalEventGenerator *>(_o);
        switch (_id) {
        case 0: _t->execute(_a); break; // HAND EDIT: add the _a parameter
        default: ;
        }
    }
    Q_UNUSED(_a);
}

const QMetaObject QSignalEventGenerator::staticMetaObject = {
    { &QObject::staticMetaObject, qt_meta_stringdata_QSignalEventGenerator.data,
      qt_meta_data_QSignalEventGenerator, qt_static_metacall, 0, 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.stringdata))
        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) {
        if (_id < 1)
            qt_static_metacall(this, _c, _id, _a);
        _id -= 1;
    }
    return _id;
}
// End moc-generated code

void QSignalEventGenerator::execute(void **_a)
{
    int signalIndex = senderSignalIndex();
    Q_ASSERT(signalIndex != -1);
    QStateMachine *machine = qobject_cast<QStateMachine*>(parent());
    QStateMachinePrivate::get(machine)->handleTransitionSignal(sender(), signalIndex, _a);
}

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

/*!
  \class QStateMachine::SignalEvent

  \brief The SignalEvent class represents a Qt signal event.

  \since 4.6
  \ingroup statemachine

  A signal event is generated by a QStateMachine in response to a Qt
  signal. The QSignalTransition class provides a transition associated with a
  signal event. QStateMachine::SignalEvent is part of \l{The State Machine Framework}.

  The sender() function returns the object that generated the signal. The
  signalIndex() function returns the index of the signal. The arguments()
  function returns the arguments of the signal.

  \sa QSignalTransition
*/

/*!
  \internal

  Constructs a new SignalEvent object with the given \a sender, \a
  signalIndex and \a arguments.
*/
QStateMachine::SignalEvent::SignalEvent(QObject *sender, int signalIndex,
                                        const QList<QVariant> &arguments)
    : QEvent(QEvent::StateMachineSignal), m_sender(sender),
      m_signalIndex(signalIndex), m_arguments(arguments)
{
}

/*!
  Destroys this SignalEvent.
*/
QStateMachine::SignalEvent::~SignalEvent()
{
}

/*!
  \fn QStateMachine::SignalEvent::sender() const

  Returns the object that emitted the signal.

  \sa QObject::sender()
*/

/*!
  \fn QStateMachine::SignalEvent::signalIndex() const

  Returns the index of the signal.

  \sa QMetaObject::indexOfSignal(), QMetaObject::method()
*/

/*!
  \fn QStateMachine::SignalEvent::arguments() const

  Returns the arguments of the signal.
*/


/*!
  \class QStateMachine::WrappedEvent

  \brief The WrappedEvent class inherits QEvent and holds a clone of an event associated with a QObject.

  \since 4.6
  \ingroup statemachine

  A wrapped event is generated by a QStateMachine in response to a Qt
  event. The QEventTransition class provides a transition associated with a
  such an event. QStateMachine::WrappedEvent is part of \l{The State Machine
  Framework}.

  The object() function returns the object that generated the event. The
  event() function returns a clone of the original event.

  \sa QEventTransition
*/

/*!
  \internal

  Constructs a new WrappedEvent object with the given \a object
  and \a event.

  The WrappedEvent object takes ownership of \a event.
*/
QStateMachine::WrappedEvent::WrappedEvent(QObject *object, QEvent *event)
    : QEvent(QEvent::StateMachineWrapped), m_object(object), m_event(event)
{
}

/*!
  Destroys this WrappedEvent.
*/
QStateMachine::WrappedEvent::~WrappedEvent()
{
    delete m_event;
}

/*!
  \fn QStateMachine::WrappedEvent::object() const

  Returns the object that the event is associated with.
*/

/*!
  \fn QStateMachine::WrappedEvent::event() const

  Returns a clone of the original event.
*/

QT_END_NAMESPACE

#include "qstatemachine.moc"
#include "moc_qstatemachine.cpp"

#endif //QT_NO_STATEMACHINE