path: root/src/declarative/util/qmlstategroup.cpp

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#include "private/qobject_p.h"
#include "qmlstategroup_p.h"
#include "qmltransition_p.h"
#include <QtDeclarative/qmlbinding.h>
#include <QtCore/qdebug.h>
#include <private/qmlglobal_p.h>

QT_BEGIN_NAMESPACE

DEFINE_BOOL_CONFIG_OPTION(stateChangeDebug, STATECHANGE_DEBUG);

QML_DEFINE_TYPE(Qt,4,6,StateGroup,QmlStateGroup)

class QmlStateGroupPrivate : public QObjectPrivate
{
    Q_DECLARE_PUBLIC(QmlStateGroup)
public:
    QmlStateGroupPrivate(QmlStateGroup *p)
    : nullState(0), states(p), componentComplete(true), ignoreTrans(false) {}

    QString currentState;
    QmlState *nullState;

    struct StateList : public QmlConcreteList<QmlState *>
    {
        StateList(QmlStateGroup *g)
            :group(g) {}
        void append(QmlState *s) {
            QmlConcreteList<QmlState *>::append(s);
            if (s) s->setStateGroup(group);
        }
    private:
        QmlStateGroup *group;
    };
    StateList states;

    QmlConcreteList<QmlTransition *> transitions;
    bool componentComplete;
    bool ignoreTrans;

    QmlTransition *findTransition(const QString &from, const QString &to);
    void setCurrentStateInternal(const QString &state, bool = false);
    void updateAutoState();
};

/*!
   \qmlclass StateGroup QmlStateGroup
   \brief The StateGroup element provides state support for non-Item elements.

   Item (and all dervied elements) provides built in support for states and transitions
   via its state, states and transitions properties. StateGroup provides an easy way to
   use this support in other (non-Item-derived) elements.

   \qml
   MyCustomObject {
       StateGroup {
           id: myStateGroup
           states: State {
               name: "state1"
               ...
           }
           transitions: Transition {
               ...
           }
       }

       onSomethingHappened: myStateGroup.state = "state1";
   }
   \endqml

   \sa {qmlstate}{States} and {state-transitions}{Transitions}
*/

QmlStateGroup::QmlStateGroup(QObject *parent)
    : QObject(*(new QmlStateGroupPrivate(this)), parent)
{
}

QmlStateGroup::~QmlStateGroup()
{
}

QList<QmlState *> QmlStateGroup::states() const
{
    Q_D(const QmlStateGroup);
    return d->states;
}

/*!
  \qmlproperty list<State> StateGroup::states
  This property holds a list of states defined by the state group.

  \qml
  StateGroup {
    states: [
      State { ... },
      State { ... }
      ...
    ]
  }
  \endqml

  \sa {qmlstate}{States}
*/
QmlList<QmlState *>* QmlStateGroup::statesProperty()
{
    Q_D(QmlStateGroup);
    return &(d->states);
}

/*!
  \qmlproperty list<Transition> StateGroup::transitions
  This property holds a list of transitions defined by the state group.

  \qml
  StateGroup {
    transitions: [
      Transition { ... },
      Transition { ... }
      ...
    ]
  }
  \endqml

  \sa {state-transitions}{Transitions}
*/
QmlList<QmlTransition *>* QmlStateGroup::transitionsProperty()
{
    Q_D(QmlStateGroup);
    return &(d->transitions);
}

/*!
  \qmlproperty string StateGroup::state

  This property holds the name of the current state of the state group.

  This property is often used in scripts to change between states. For
  example:

  \qml
    Script {
        function toggle() {
            if (button.state == 'On')
                button.state = 'Off';
            else
                button.state = 'On';
        }
    }
  \endqml

  If the state group is in its base state (i.e. no explicit state has been
  set), \c state will be a blank string. Likewise, you can return a
  state group to its base state by setting its current state to \c ''.

  \sa {qmlstates}{States}
*/
QString QmlStateGroup::state() const
{
    Q_D(const QmlStateGroup);
    return d->currentState;
}

void QmlStateGroup::setState(const QString &state)
{
    Q_D(QmlStateGroup);
    if (d->currentState == state)
        return;

    d->setCurrentStateInternal(state);

    d->currentState = state;
    emit stateChanged(d->currentState);
}

void QmlStateGroup::classBegin()
{
    Q_D(QmlStateGroup);
    d->componentComplete = false;
}

void QmlStateGroup::componentComplete()
{
    Q_D(QmlStateGroup);
    d->componentComplete = true;
    d->updateAutoState();
    if (!d->currentState.isEmpty()) {
        QString cs = d->currentState;
        d->currentState = QString();
        d->setCurrentStateInternal(cs, true);
    }
}

void QmlStateGroup::updateAutoState()
{
    Q_D(QmlStateGroup);
    d->updateAutoState();
}

void QmlStateGroupPrivate::updateAutoState()
{
    Q_Q(QmlStateGroup);
    if (!componentComplete)
        return;

    bool revert = false;
    for (int ii = 0; ii < states.count(); ++ii) {
        QmlState *state = states.at(ii);
        if (state->isWhenKnown()) {
            if (!state->name().isEmpty()) {
                if (state->when() && state->when()->value().toBool()) {
                    if (stateChangeDebug()) 
                        qWarning() << "Setting auto state due to:" 
                                   << state->when()->expression();
                    q->setState(state->name());
                    return;
                } else if (state->name() == currentState) {
                    revert = true;
                }
            }
        }
    }
    if (revert)
        q->setState(QString());
}

QmlTransition *QmlStateGroupPrivate::findTransition(const QString &from, const QString &to)
{
    QmlTransition *highest = 0;
    int score = 0;
    bool reversed = false;
    bool done = false;

    for (int ii = 0; !done && ii < transitions.count(); ++ii) {
        QmlTransition *t = transitions.at(ii);
        for (int ii = 0; ii < 2; ++ii)
        {
            if (ii && (!t->reversible() ||
                      (t->fromState() == QLatin1String("*") && 
                       t->toState() == QLatin1String("*"))))
                break;
            QStringList fromState;
            QStringList toState;

            fromState = t->fromState().split(QLatin1Char(','));
            toState = t->toState().split(QLatin1Char(','));
            if (ii == 1)
                qSwap(fromState, toState);
            int tScore = 0;
            if (fromState.contains(from))
                tScore += 2;
            else if (fromState.contains(QLatin1String("*")))
                tScore += 1;
            else
                continue;

            if (toState.contains(to))
                tScore += 2;
            else if (toState.contains(QLatin1String("*")))
                tScore += 1;
            else
                continue;

            if (ii == 1)
                reversed = true;
            else
                reversed = false;

            if (tScore == 4) {
                highest = t;
                done = true;
                break;
            } else if (tScore > score) {
                score = tScore;
                highest = t;
            }
        }
    }

    if (highest)
        highest->setReversed(reversed);

    return highest;
}

void QmlStateGroupPrivate::setCurrentStateInternal(const QString &state, 
                                                   bool ignoreTrans)
{
    Q_Q(QmlStateGroup);
    if (!componentComplete)
        return;

    QmlTransition *transition = (ignoreTrans || ignoreTrans) ? 0 : findTransition(currentState, state);
    if (stateChangeDebug()) {
        qWarning() << this << "Changing state.  From" << currentState << ". To" << state;
        if (transition)
            qWarning() << "   using transition" << transition->fromState() 
                       << transition->toState();
    }

    QmlState *oldState = 0;
    if (!currentState.isEmpty()) {
        for (int ii = 0; ii < states.count(); ++ii) {
            if (states.at(ii)->name() == currentState) {
                oldState = states.at(ii);
                break;
            }
        }
    }

    currentState = state;

    QmlState *newState = 0;
    for (int ii = 0; ii < states.count(); ++ii) {
        if (states.at(ii)->name() == currentState) {
            newState = states.at(ii);
            break;
        }
    }

    if (oldState == 0 || newState == 0) {
        if (!nullState) { nullState = new QmlState; QmlGraphics_setParent_noEvent(nullState, q); }
        if (!oldState) oldState = nullState;
        if (!newState) newState = nullState;
    }

    newState->apply(q, transition, oldState);
}

QmlState *QmlStateGroup::findState(const QString &name) const
{
    Q_D(const QmlStateGroup);
    for (int i = 0; i < d->states.count(); ++i) {
        QmlState *state = d->states.at(i);
        if (state->name() == name)
            return state;
    }

    return 0;
}

QT_END_NAMESPACE