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

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#include "private/qdeclarativestate_p_p.h"
#include "private/qdeclarativestate_p.h"

#include "private/qdeclarativetransition_p.h"
#include "private/qdeclarativestategroup_p.h"
#include "private/qdeclarativestateoperations_p.h"
#include "private/qdeclarativeanimation_p.h"
#include "private/qdeclarativeanimation_p_p.h"

#include <qdeclarativebinding_p.h>
#include <qdeclarativeglobal_p.h>

#include <QtCore/qdebug.h>

QT_BEGIN_NAMESPACE

DEFINE_BOOL_CONFIG_OPTION(stateChangeDebug, STATECHANGE_DEBUG);

QDeclarativeAction::QDeclarativeAction()
: restore(true), actionDone(false), reverseEvent(false), deletableToBinding(false), fromBinding(0), toBinding(0), event(0),
  specifiedObject(0)
{
}

QDeclarativeAction::QDeclarativeAction(QObject *target, const QString &propertyName,
               const QVariant &value)
: restore(true), actionDone(false), reverseEvent(false), deletableToBinding(false), 
  property(target, propertyName), toValue(value), 
  fromBinding(0), toBinding(0), event(0), 
  specifiedObject(target), specifiedProperty(propertyName)
{
    if (property.isValid())
        fromValue = property.read();
}

QDeclarativeActionEvent::~QDeclarativeActionEvent()
{
}

QString QDeclarativeActionEvent::typeName() const
{
    return QString();
}

void QDeclarativeActionEvent::execute()
{
}

bool QDeclarativeActionEvent::isReversable()
{
    return false;
}

void QDeclarativeActionEvent::reverse()
{
}

bool QDeclarativeActionEvent::changesBindings()
{
    return false;
}

void QDeclarativeActionEvent::clearBindings()
{
}

bool QDeclarativeActionEvent::override(QDeclarativeActionEvent *other)
{
    Q_UNUSED(other);
    return false;
}

/*!
    \internal
*/
QDeclarativeStateOperation::QDeclarativeStateOperation(QObjectPrivate &dd, QObject *parent)
    : QObject(dd, parent)
{
}

/*!
    \qmlclass State QDeclarativeState
  \since 4.7
    \brief The State element defines configurations of objects and properties.

    A state is specified as a set of batched changes from the default configuration.

    Note that setting the state of an object from within another state of the same object is
    inadvisible. Not only would this have the same effect as going directly to the second state
    it may cause the program to crash.

    \sa {qmlstates}{States}, {state-transitions}{Transitions}
*/

/*!
    \internal
    \class QDeclarativeState
    \brief The QDeclarativeState class allows you to define configurations of objects and properties.

    \ingroup group_states

    QDeclarativeState allows you to specify a state as a set of batched changes from the default
    configuration.

    \sa {states-transitions}{States and Transitions}
*/


QDeclarativeState::QDeclarativeState(QObject *parent)
: QObject(*(new QDeclarativeStatePrivate), parent)
{
    Q_D(QDeclarativeState);
    d->transitionManager.setState(this);
}

QDeclarativeState::~QDeclarativeState()
{
    Q_D(QDeclarativeState);
    if (d->group)
        d->group->removeState(this);
}

/*!
    \qmlproperty string State::name
    This property holds the name of the state

    Each state should have a unique name.
*/
QString QDeclarativeState::name() const
{
    Q_D(const QDeclarativeState);
    return d->name;
}

void QDeclarativeState::setName(const QString &n)
{
    Q_D(QDeclarativeState);
    d->name = n;
}

bool QDeclarativeState::isWhenKnown() const
{
    Q_D(const QDeclarativeState);
    return d->when != 0;
}

/*!
    \qmlproperty bool State::when
    This property holds when the state should be applied

    This should be set to an expression that evaluates to true when you want the state to
    be applied.
*/
QDeclarativeBinding *QDeclarativeState::when() const
{
    Q_D(const QDeclarativeState);
    return d->when;
}

void QDeclarativeState::setWhen(QDeclarativeBinding *when)
{
    Q_D(QDeclarativeState);
    d->when = when;
    if (d->group)
        d->group->updateAutoState();
}

/*!
    \qmlproperty string State::extend
    This property holds the state that this state extends

    The state being extended is treated as the base state in regards to
    the changes specified by the extending state.
*/
QString QDeclarativeState::extends() const
{
    Q_D(const QDeclarativeState);
    return d->extends;
}

void QDeclarativeState::setExtends(const QString &extends)
{
    Q_D(QDeclarativeState);
    d->extends = extends;
}

/*!
    \qmlproperty list<Change> State::changes
    This property holds the changes to apply for this state
    \default

    By default these changes are applied against the default state. If the state
    extends another state, then the changes are applied against the state being
    extended.
*/
QDeclarativeListProperty<QDeclarativeStateOperation> QDeclarativeState::changes()
{
    Q_D(QDeclarativeState);
    return QDeclarativeListProperty<QDeclarativeStateOperation>(this, &d->operations, QDeclarativeStatePrivate::operations_append,
                                              QDeclarativeStatePrivate::operations_count, QDeclarativeStatePrivate::operations_at,
                                              QDeclarativeStatePrivate::operations_clear);
}

int QDeclarativeState::operationCount() const
{
    Q_D(const QDeclarativeState);
    return d->operations.count();
}

QDeclarativeStateOperation *QDeclarativeState::operationAt(int index) const
{
    Q_D(const QDeclarativeState);
    return d->operations.at(index);
}

QDeclarativeState &QDeclarativeState::operator<<(QDeclarativeStateOperation *op)
{
    Q_D(QDeclarativeState);
    d->operations.append(QDeclarativeStatePrivate::OperationGuard(op, &d->operations));
    return *this;
}

void QDeclarativeStatePrivate::complete()
{
    Q_Q(QDeclarativeState);

    for (int ii = 0; ii < reverting.count(); ++ii) {
        for (int jj = 0; jj < revertList.count(); ++jj) {
            if (revertList.at(jj).property == reverting.at(ii)) {
                revertList.removeAt(jj);
                break;
            }
        }
    }
    reverting.clear();

    emit q->completed();
}

// Generate a list of actions for this state.  This includes coelescing state
// actions that this state "extends"
QDeclarativeStateOperation::ActionList
QDeclarativeStatePrivate::generateActionList(QDeclarativeStateGroup *group) const
{
    QDeclarativeStateOperation::ActionList applyList;
    if (inState)
        return applyList;

    // Prevent "extends" recursion
    inState = true;

    if (!extends.isEmpty()) {
        QList<QDeclarativeState *> states = group->states();
        for (int ii = 0; ii < states.count(); ++ii)
            if (states.at(ii)->name() == extends)
                applyList = static_cast<QDeclarativeStatePrivate*>(states.at(ii)->d_func())->generateActionList(group);
    }

    foreach(QDeclarativeStateOperation *op, operations)
        applyList << op->actions();

    inState = false;
    return applyList;
}

QDeclarativeStateGroup *QDeclarativeState::stateGroup() const
{
    Q_D(const QDeclarativeState);
    return d->group;
}

void QDeclarativeState::setStateGroup(QDeclarativeStateGroup *group)
{
    Q_D(QDeclarativeState);
    d->group = group;
}

void QDeclarativeState::cancel()
{
    Q_D(QDeclarativeState);
    d->transitionManager.cancel();
}

void QDeclarativeAction::deleteFromBinding()
{
    if (fromBinding) {
        QDeclarativePropertyPrivate::setBinding(property, 0);
        fromBinding->destroy();
        fromBinding = 0;
    }
}

void QDeclarativeState::apply(QDeclarativeStateGroup *group, QDeclarativeTransition *trans, QDeclarativeState *revert)
{
    Q_D(QDeclarativeState);

    qmlExecuteDeferred(this);

    cancel();
    if (revert)
        revert->cancel();
    d->revertList.clear();
    d->reverting.clear();

    if (revert) {
        QDeclarativeStatePrivate *revertPrivate =
            static_cast<QDeclarativeStatePrivate*>(revert->d_func());
        d->revertList = revertPrivate->revertList;
        revertPrivate->revertList.clear();
    }

    // List of actions caused by this state
    QDeclarativeStateOperation::ActionList applyList = d->generateActionList(group);

    // List of actions that need to be reverted to roll back (just) this state
    QDeclarativeStatePrivate::SimpleActionList additionalReverts;
    // First add the reverse of all the applyList actions
    for (int ii = 0; ii < applyList.count(); ++ii) {
        QDeclarativeAction &action = applyList[ii];

        if (action.event) {
            if (!action.event->isReversable())
                continue;
            bool found = false;
            for (int jj = 0; jj < d->revertList.count(); ++jj) {
                QDeclarativeActionEvent *event = d->revertList.at(jj).event;
                if (event && event->typeName() == action.event->typeName()) {
                    if (action.event->override(event)) {
                        found = true;

                        if (action.event != d->revertList.at(jj).event) {
                            action.event->copyOriginals(d->revertList.at(jj).event);

                            QDeclarativeSimpleAction r(action);
                            additionalReverts << r;
                            d->revertList.removeAt(jj);
                        } else if (action.event->isRewindable())    //###why needed?
                            action.event->saveCurrentValues();

                        break;
                    }
                }
            }
            if (!found) {
                action.event->saveOriginals();
                // Only need to revert the applyList action if the previous
                // state doesn't have a higher priority revert already
                QDeclarativeSimpleAction r(action);
                additionalReverts << r;
            }
        } else {
            bool found = false;
            action.fromBinding = QDeclarativePropertyPrivate::binding(action.property);

            for (int jj = 0; jj < d->revertList.count(); ++jj) {
                if (d->revertList.at(jj).property == action.property) {
                    found = true;
                    if (d->revertList.at(jj).binding != action.fromBinding) {
                        action.deleteFromBinding();
                    }
                    break;
                }
            }

            if (!found) {
                if (!action.restore) {
                    action.deleteFromBinding();
                } else {
                    // Only need to revert the applyList action if the previous
                    // state doesn't have a higher priority revert already
                    QDeclarativeSimpleAction r(action);
                    additionalReverts << r;
                }
            }
        }
    }

    // Any reverts from a previous state that aren't carried forth
    // into this state need to be translated into apply actions
    for (int ii = 0; ii < d->revertList.count(); ++ii) {
        bool found = false;
        if (d->revertList.at(ii).event) {
            QDeclarativeActionEvent *event = d->revertList.at(ii).event;
            if (!event->isReversable())
                continue;
            for (int jj = 0; !found && jj < applyList.count(); ++jj) {
                const QDeclarativeAction &action = applyList.at(jj);
                if (action.event && action.event->typeName() == event->typeName()) {
                    if (action.event->override(event))
                        found = true;
                }
            }
        } else {
            for (int jj = 0; !found && jj < applyList.count(); ++jj) {
                const QDeclarativeAction &action = applyList.at(jj);
                if (action.property == d->revertList.at(ii).property)
                    found = true;
            }
        }
        if (!found) {
            QVariant cur = d->revertList.at(ii).property.read();
            QDeclarativeAbstractBinding *delBinding = 
                QDeclarativePropertyPrivate::setBinding(d->revertList.at(ii).property, 0);
            if (delBinding)
                delBinding->destroy();

            QDeclarativeAction a;
            a.property = d->revertList.at(ii).property;
            a.fromValue = cur;
            a.toValue = d->revertList.at(ii).value;
            a.toBinding = d->revertList.at(ii).binding;
            a.specifiedObject = d->revertList.at(ii).specifiedObject;
            a.specifiedProperty = d->revertList.at(ii).specifiedProperty;
            a.event = d->revertList.at(ii).event;
            a.reverseEvent = d->revertList.at(ii).reverseEvent;
            if (a.event && a.event->isRewindable())
                a.event->saveCurrentValues();
            applyList << a;
            // Store these special reverts in the reverting list
            d->reverting << d->revertList.at(ii).property;
        }
    }
    // All the local reverts now become part of the ongoing revertList
    d->revertList << additionalReverts;

    // Output for debugging
    if (stateChangeDebug()) {
        foreach(const QDeclarativeAction &action, applyList) {
            if (action.event)
                qWarning() << "    QDeclarativeAction event:" << action.event->typeName();
            else
                qWarning() << "    QDeclarativeAction:" << action.property.object()
                           << action.property.name() << "From:" << action.fromValue 
                           << "To:" << action.toValue;
        }
    }

    d->transitionManager.transition(applyList, trans);
}

QDeclarativeStateOperation::ActionList QDeclarativeStateOperation::actions()
{
    return ActionList();
}

QT_END_NAMESPACE