qquickstate.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include "qquickstate_p_p.h"
#include "qquickstate_p.h"
 
#include "qquickstategroup_p.h"
#include "qquickstatechangescript_p.h"
 
#include <private/qqmlglobal_p.h>
 
#include <QtCore/qdebug.h>
 
QT_BEGIN_NAMESPACE
 
Q_LOGGING_CATEGORY(lcStates, "qt.qml.states")
 
QQuickStateAction::QQuickStateAction()
: restore(true), actionDone(false), reverseEvent(false), deletableToBinding(false), fromBinding(nullptr), event(nullptr),
  specifiedObject(nullptr)
{
}
 
QQuickStateAction::QQuickStateAction(QObject *target, const QString &propertyName,
               const QVariant &value)
: restore(true), actionDone(false), reverseEvent(false), deletableToBinding(false),
  property(target, propertyName, qmlEngine(target)), toValue(value),
  fromBinding(nullptr), event(nullptr),
  specifiedObject(target), specifiedProperty(propertyName)
{
    if (property.isValid())
        fromValue = property.read();
}
 
QQuickStateAction::QQuickStateAction(QObject *target, const QQmlProperty &property, const QString &propertyName, const QVariant &value)
: restore(true), actionDone(false), reverseEvent(false), deletableToBinding(false),
  property(property), toValue(value),
  fromBinding(nullptr), event(nullptr),
  specifiedObject(target), specifiedProperty(propertyName)
{
    if (property.isValid())
        fromValue = property.read();
}
 
 
QQuickStateActionEvent::~QQuickStateActionEvent()
{
}
 
void QQuickStateActionEvent::execute()
{
}
 
bool QQuickStateActionEvent::isReversable()
{
    return false;
}
 
void QQuickStateActionEvent::reverse()
{
}
 
bool QQuickStateActionEvent::changesBindings()
{
    return false;
}
 
void QQuickStateActionEvent::clearBindings()
{
}
 
bool QQuickStateActionEvent::mayOverride(QQuickStateActionEvent *other)
{
    Q_UNUSED(other);
    return false;
}
 
QQuickStateOperation::QQuickStateOperation(QObjectPrivate &dd, QObject *parent)
    : QObject(dd, parent)
{
}
 
QQuickState::QQuickState(QObject *parent)
: QObject(*(new QQuickStatePrivate), parent)
{
    Q_D(QQuickState);
    d->transitionManager.setState(this);
}
 
QQuickState::~QQuickState()
{
    Q_D(QQuickState);
    if (d->group)
        d->group->removeState(this);
}
 
QString QQuickState::name() const
{
    Q_D(const QQuickState);
    return d->name;
}
 
void QQuickState::setName(const QString &n)
{
    Q_D(QQuickState);
    d->name = n;
    d->named = true;
}
 
bool QQuickState::isNamed() const
{
    Q_D(const QQuickState);
    return d->named;
}
 
bool QQuickState::isWhenKnown() const
{
    Q_D(const QQuickState);
    return d->whenKnown;
}
 
bool QQuickState::when() const
{
    Q_D(const QQuickState);
    return d->when;
}
 
void QQuickState::setWhen(bool when)
{
    Q_D(QQuickState);
    d->whenKnown = true;
    d->when = when;
    if (d->group)
        d->group->updateAutoState();
}
 
QString QQuickState::extends() const
{
    Q_D(const QQuickState);
    return d->extends;
}
 
void QQuickState::setExtends(const QString &extends)
{
    Q_D(QQuickState);
    d->extends = extends;
}
 
QQmlListProperty<QQuickStateOperation> QQuickState::changes()
{
    Q_D(QQuickState);
    return QQmlListProperty<QQuickStateOperation>(this, &d->operations,
                                                  QQuickStatePrivate::operations_append,
                                                  QQuickStatePrivate::operations_count,
                                                  QQuickStatePrivate::operations_at,
                                                  QQuickStatePrivate::operations_clear,
                                                  QQuickStatePrivate::operations_replace,
                                                  QQuickStatePrivate::operations_removeLast);
}
 
int QQuickState::operationCount() const
{
    Q_D(const QQuickState);
    return d->operations.size();
}
 
QQuickStateOperation *QQuickState::operationAt(int index) const
{
    Q_D(const QQuickState);
    return d->operations.at(index);
}
 
QQuickState &QQuickState::operator<<(QQuickStateOperation *op)
{
    Q_D(QQuickState);
    d->operations.append(QQuickStatePrivate::OperationGuard(op, &d->operations));
    return *this;
}
 
void QQuickStatePrivate::complete()
{
    Q_Q(QQuickState);
 
    for (int ii = 0; ii < reverting.size(); ++ii) {
        for (int jj = 0; jj < revertList.size(); ++jj) {
            const QQuickRevertAction &revert = reverting.at(ii);
            const QQuickSimpleAction &simple = revertList.at(jj);
            if ((revert.event && simple.event() == revert.event) ||
                simple.property() == revert.property) {
                revertList.removeAt(jj);
                break;
            }
        }
    }
    reverting.clear();
 
    if (group)
        group->stateAboutToComplete();
    emit q->completed();
}
 
// Generate a list of actions for this state.  This includes coelescing state
// actions that this state "extends"
QQuickStateOperation::ActionList
QQuickStatePrivate::generateActionList() const
{
    QQuickStateOperation::ActionList applyList;
    if (inState)
        return applyList;
 
    // Prevent "extends" recursion
    inState = true;
 
    if (!extends.isEmpty()) {
        QList<QQuickState *> states = group ? group->states() : QList<QQuickState *>();
        for (int ii = 0; ii < states.size(); ++ii)
            if (states.at(ii)->name() == extends) {
                qmlExecuteDeferred(states.at(ii));
                applyList = static_cast<QQuickStatePrivate*>(states.at(ii)->d_func())->generateActionList();
            }
    }
 
    for (QQuickStateOperation *op : operations)
        applyList << op->actions();
 
    inState = false;
    return applyList;
}
 
QQuickStateGroup *QQuickState::stateGroup() const
{
    Q_D(const QQuickState);
    return d->group;
}
 
void QQuickState::setStateGroup(QQuickStateGroup *group)
{
    Q_D(QQuickState);
    d->group = group;
}
 
void QQuickState::cancel()
{
    Q_D(QQuickState);
    d->transitionManager.cancel();
}
 
void QQuickStateAction::deleteFromBinding()
{
    if (fromBinding) {
        if (fromBinding.isAbstractPropertyBinding()) {
            QQmlPropertyPrivate::removeBinding(property);
            fromBinding = nullptr;
        }
    }
}
 
bool QQuickState::containsPropertyInRevertList(QObject *target, const QString &name) const
{
    Q_D(const QQuickState);
 
    if (isStateActive()) {
        for (const QQuickSimpleAction &simpleAction : d->revertList) {
            if (simpleAction.specifiedObject() == target && simpleAction.specifiedProperty() == name)
                return true;
        }
    }
 
    return false;
}
 
bool QQuickState::changeValueInRevertList(QObject *target, const QString &name, const QVariant &revertValue)
{
    Q_D(QQuickState);
 
    if (isStateActive()) {
        for (QQuickSimpleAction &simpleAction : d->revertList) {
            if (simpleAction.specifiedObject() == target && simpleAction.specifiedProperty() == name) {
                    simpleAction.setValue(revertValue);
                    return true;
            }
        }
    }
 
    return false;
}
 
bool QQuickState::changeBindingInRevertList(QObject *target, const QString &name, QQmlAnyBinding binding)
{
    Q_D(QQuickState);
 
    if (isStateActive()) {
        for (QQuickSimpleAction &simpleAction : d->revertList) {
            if (simpleAction.specifiedObject() == target && simpleAction.specifiedProperty() == name) {
                simpleAction.setBinding(binding);
                return true;
            }
        }
    }
 
    return false;
}
 
bool QQuickState::removeEntryFromRevertList(QObject *target, const QString &name)
{
    Q_D(QQuickState);
 
    if (isStateActive()) {
        for (auto it = d->revertList.begin(), end = d->revertList.end(); it != end; ++it) {
            QQuickSimpleAction &simpleAction = *it;
            if (simpleAction.property().object() == target && simpleAction.property().name() == name) {
                QQmlPropertyPrivate::removeBinding(simpleAction.property());
 
                simpleAction.property().write(simpleAction.value());
                if (auto binding = simpleAction.binding(); binding) {
                    QQmlProperty prop = simpleAction.property();
                    binding.installOn(prop);
                }
 
                d->revertList.erase(it);
                return true;
            }
        }
    }
 
    return false;
}
 
void QQuickState::addEntryToRevertList(const QQuickStateAction &action)
{
    Q_D(QQuickState);
 
    QQuickSimpleAction simpleAction(action);
 
    d->revertList.append(simpleAction);
}
 
void QQuickState::removeAllEntriesFromRevertList(QObject *target)
{
    Q_D(QQuickState);
 
    if (isStateActive()) {
        const auto actionMatchesTarget = [target](const QQuickSimpleAction &simpleAction) {
            if (simpleAction.property().object() == target) {
                QQmlPropertyPrivate::removeBinding(simpleAction.property());
                simpleAction.property().write(simpleAction.value());
                if (auto binding = simpleAction.binding()) {
                    QQmlProperty prop = simpleAction.property();
                    binding.installOn(prop);
                }
 
                return true;
            }
            return false;
        };
 
        d->revertList.removeIf(actionMatchesTarget);
    }
}
 
void QQuickState::addEntriesToRevertList(const QList<QQuickStateAction> &actionList)
{
    Q_D(QQuickState);
    if (isStateActive()) {
        QList<QQuickSimpleAction> simpleActionList;
        simpleActionList.reserve(actionList.size());
 
        for (const QQuickStateAction &action : actionList) {
            QQuickSimpleAction simpleAction(action);
            action.property.write(action.toValue);
            if (auto binding = action.toBinding; binding)
                binding.installOn(action.property);
 
            simpleActionList.append(simpleAction);
        }
 
        d->revertList.append(simpleActionList);
    }
}
 
QVariant QQuickState::valueInRevertList(QObject *target, const QString &name) const
{
    Q_D(const QQuickState);
 
    if (isStateActive()) {
        for (const QQuickSimpleAction &simpleAction : d->revertList) {
            if (simpleAction.specifiedObject() == target && simpleAction.specifiedProperty() == name)
                return simpleAction.value();
        }
    }
 
    return QVariant();
}
 
QQmlAnyBinding QQuickState::bindingInRevertList(QObject *target, const QString &name) const
{
    Q_D(const QQuickState);
 
    if (isStateActive()) {
        for (const QQuickSimpleAction &simpleAction : d->revertList) {
            if (simpleAction.specifiedObject() == target && simpleAction.specifiedProperty() == name)
                return simpleAction.binding();
        }
    }
 
    return nullptr;
}
 
bool QQuickState::isStateActive() const
{
    return stateGroup() && stateGroup()->state() == name();
}
 
void QQuickState::apply(QQuickTransition *trans, QQuickState *revert)
{
    Q_D(QQuickState);
 
    qmlExecuteDeferred(this);
 
    cancel();
    if (revert)
        revert->cancel();
    d->revertList.clear();
    d->reverting.clear();
 
    if (revert) {
        QQuickStatePrivate *revertPrivate =
            static_cast<QQuickStatePrivate*>(revert->d_func());
        d->revertList = revertPrivate->revertList;
        revertPrivate->revertList.clear();
    }
 
    // List of actions caused by this state
    QQuickStateOperation::ActionList applyList = d->generateActionList();
 
    // List of actions that need to be reverted to roll back (just) this state
    QQuickStatePrivate::SimpleActionList additionalReverts;
    // First add the reverse of all the applyList actions
    for (int ii = 0; ii < applyList.size(); ++ii) {
        QQuickStateAction &action = applyList[ii];
 
        if (action.event) {
            if (!action.event->isReversable())
                continue;
            bool found = false;
            for (int jj = 0; jj < d->revertList.size(); ++jj) {
                QQuickStateActionEvent *event = d->revertList.at(jj).event();
                if (event && event->type() == action.event->type()) {
                    if (action.event->mayOverride(event)) {
                        found = true;
 
                        if (action.event != d->revertList.at(jj).event() && action.event->needsCopy()) {
                            action.event->copyOriginals(d->revertList.at(jj).event());
 
                            QQuickSimpleAction r(action);
                            additionalReverts << r;
                            d->revertList.removeAt(jj);
                            --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
                QQuickSimpleAction r(action);
                additionalReverts << r;
            }
        } else {
            bool found = false;
            action.fromBinding = QQmlAnyBinding::ofProperty(action.property);
 
            for (int jj = 0; jj < d->revertList.size(); ++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
                    QQuickSimpleAction 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.size(); ++ii) {
        bool found = false;
        if (d->revertList.at(ii).event()) {
            QQuickStateActionEvent *event = d->revertList.at(ii).event();
            if (!event->isReversable())
                continue;
            for (int jj = 0; !found && jj < applyList.size(); ++jj) {
                const QQuickStateAction &action = applyList.at(jj);
                if (action.event && action.event->type() == event->type()) {
                    if (action.event->mayOverride(event))
                        found = true;
                }
            }
        } else {
            for (int jj = 0; !found && jj < applyList.size(); ++jj) {
                const QQuickStateAction &action = applyList.at(jj);
                if (action.property == d->revertList.at(ii).property())
                    found = true;
            }
        }
        if (!found) {
            // If revert list contains bindings assigned to deleted objects, we need to
            // prevent reverting properties of those objects.
            if (d->revertList.at(ii).binding() && !d->revertList.at(ii).property().object()) {
                continue;
            }
            QVariant cur = d->revertList.at(ii).property().read();
            QQmlProperty prop = d->revertList.at(ii).property();
            QQmlAnyBinding::removeBindingFrom(prop);
 
            QQuickStateAction 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
            if (a.event)
                d->reverting << a.event;
            else
                d->reverting << a.property;
        }
    }
    // All the local reverts now become part of the ongoing revertList
    d->revertList << additionalReverts;
 
    if (lcStates().isDebugEnabled()) {
        for (const QQuickStateAction &action : std::as_const(applyList)) {
            if (action.event)
                qCDebug(lcStates) << "QQuickStateAction event:" << action.event->type();
            else
                qCDebug(lcStates) << "QQuickStateAction on" << action.property.object()
                                  << action.property.name() << "from:" << action.fromValue
                                  << "to:" << action.toValue;
        }
    }
 
    d->transitionManager.transition(applyList, trans);
}
 
QQuickStateOperation::ActionList QQuickStateOperation::actions()
{
    return ActionList();
}
 
QQuickState *QQuickStateOperation::state() const
{
    Q_D(const QQuickStateOperation);
    return d->m_state;
}
 
void QQuickStateOperation::setState(QQuickState *state)
{
    Q_D(QQuickStateOperation);
    d->m_state = state;
}
 
QT_END_NAMESPACE
 
#include "moc_qquickstate_p.cpp"