text: /****************************************************************************
  **
  ** Copyright (C) 2016 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the QtQuick module of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:LGPL$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** GNU Lesser General Public License Usage
  ** Alternatively, this file may be used under the terms of the GNU Lesser
  ** General Public License version 3 as published by the Free Software
  ** Foundation and appearing in the file LICENSE.LGPL3 included in the
  ** packaging of this file. Please review the following information to
  ** ensure the GNU Lesser General Public License version 3 requirements
  ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
  **
  ** GNU General Public License Usage
  ** Alternatively, this file may be used under the terms of the GNU
  ** General Public License version 2.0 or (at your option) the GNU General
  ** Public license version 3 or any later version approved by the KDE Free
  ** Qt Foundation. The licenses are as published by the Free Software
  ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
  ** included in the packaging of this file. Please review the following
  ** information to ensure the GNU General Public License requirements will
  ** be met: https://www.gnu.org/licenses/gpl-2.0.html and
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  **
  ** $QT_END_LICENSE$
  **
  ****************************************************************************/
  
  #ifndef QQUICKSTATE_H
  #define QQUICKSTATE_H
  
  //
  //  W A R N I N G
  //  -------------
  //
  // This file is not part of the Qt API.  It exists purely as an
  // implementation detail.  This header file may change from version to
  // version without notice, or even be removed.
  //
  // We mean it.
  //
  
  #include <qqml.h>
  #include <qqmlproperty.h>
  #include <QtCore/qobject.h>
  #include <QtCore/qsharedpointer.h>
  #include <private/qtquickglobal_p.h>
  #include <private/qqmlabstractbinding_p.h>
  
  QT_BEGIN_NAMESPACE
  
  class QQuickStateActionEvent;
  class QQmlBinding;
  class QQmlExpression;
  
  class Q_QUICK_PRIVATE_EXPORT QQuickStateAction
  {
  public:
      QQuickStateAction();
      QQuickStateAction(QObject *, const QString &, const QVariant &);
      QQuickStateAction(QObject *, const QQmlProperty &property, const QString &,
                        const QVariant &);
  
      bool restore:1;
      bool actionDone:1;
      bool reverseEvent:1;
      bool deletableToBinding:1;
  
      QQmlProperty property;
      QVariant fromValue;
      QVariant toValue;
  
      QQmlAbstractBinding::Ptr fromBinding;
      QQmlAbstractBinding::Ptr toBinding;
      QQuickStateActionEvent *event;
  
      //strictly for matching
      QObject *specifiedObject;
      QString specifiedProperty;
  
      void deleteFromBinding();
  };
  
  class Q_AUTOTEST_EXPORT QQuickStateActionEvent
  {
  public:
      virtual ~QQuickStateActionEvent();
  
      enum EventType { Script, SignalHandler, ParentChange, AnchorChanges };
  
      virtual EventType type() const = 0;
  
      virtual void execute();
      virtual bool isReversable();
      virtual void reverse();
      virtual void saveOriginals() {}
      virtual bool needsCopy() { return false; }
      virtual void copyOriginals(QQuickStateActionEvent *) {}
  
      virtual bool isRewindable() { return isReversable(); }
      virtual void rewind() {}
      virtual void saveCurrentValues() {}
      virtual void saveTargetValues() {}
  
      virtual bool changesBindings();
      virtual void clearBindings();
      virtual bool mayOverride(QQuickStateActionEvent*other);
  };
  
  //### rename to QQuickStateChange?
  class QQuickStateGroup;
  class QQuickState;
  class QQuickStateOperationPrivate;
  class Q_QUICK_PRIVATE_EXPORT QQuickStateOperation : public QObject
  {
      Q_OBJECT
  public:
      QQuickStateOperation(QObject *parent = nullptr)
          : QObject(parent) {}
      typedef QList<QQuickStateAction> ActionList;
  
      virtual ActionList actions();
  
      QQuickState *state() const;
      void setState(QQuickState *state);
  
  protected:
      QQuickStateOperation(QObjectPrivate &dd, QObject *parent = nullptr);
  
  private:
      Q_DECLARE_PRIVATE(QQuickStateOperation)
      Q_DISABLE_COPY(QQuickStateOperation)
  };
  
  typedef QQuickStateOperation::ActionList QQuickStateActions;
  
  class QQuickTransition;
  class QQuickStatePrivate;
  class Q_QUICK_PRIVATE_EXPORT QQuickState : public QObject
  {
      Q_OBJECT
  
      Q_PROPERTY(QString name READ name WRITE setName)
      Q_PROPERTY(bool when READ when WRITE setWhen)
      Q_PROPERTY(QString extend READ extends WRITE setExtends)
      Q_PROPERTY(QQmlListProperty<QQuickStateOperation> changes READ changes)
      Q_CLASSINFO("DefaultProperty", "changes")
      Q_CLASSINFO("DeferredPropertyNames", "changes")
  
  public:
      QQuickState(QObject *parent=nullptr);
      ~QQuickState() override;
  
      QString name() const;
      void setName(const QString &);
      bool isNamed() const;
  
      bool isWhenKnown() const;
      bool when() const;
      void setWhen(bool);
  
      QString extends() const;
      void setExtends(const QString &);
  
      QQmlListProperty<QQuickStateOperation> changes();
      int operationCount() const;
      QQuickStateOperation *operationAt(int) const;
  
      QQuickState &operator<<(QQuickStateOperation *);
  
      void apply(QQuickTransition *, QQuickState *revert);
      void cancel();
  
      QQuickStateGroup *stateGroup() const;
      void setStateGroup(QQuickStateGroup *);
  
      bool containsPropertyInRevertList(QObject *target, const QString &name) const;
      bool changeValueInRevertList(QObject *target, const QString &name, const QVariant &revertValue);
      bool changeBindingInRevertList(QObject *target, const QString &name, QQmlAbstractBinding *binding);
      bool removeEntryFromRevertList(QObject *target, const QString &name);
      void addEntryToRevertList(const QQuickStateAction &action);
      void removeAllEntriesFromRevertList(QObject *target);
      void addEntriesToRevertList(const QList<QQuickStateAction> &actions);
      QVariant valueInRevertList(QObject *target, const QString &name) const;
      QQmlAbstractBinding *bindingInRevertList(QObject *target, const QString &name) const;
  
      bool isStateActive() const;
  
  Q_SIGNALS:
      void completed();
  
  private:
      Q_DECLARE_PRIVATE(QQuickState)
      Q_DISABLE_COPY(QQuickState)
  };
  
  QT_END_NAMESPACE
  
  QML_DECLARE_TYPE(QQuickStateOperation)
  QML_DECLARE_TYPE(QQuickState)
  
  #endif // QQUICKSTATE_H
  