File indexing completed on 2024-05-12 04:43:04

 /***************************************************************************
  *   Copyright (C) 2017-2018 by Emmanuel Lepage Vallee                     *
  *   Author : Emmanuel Lepage Vallee <emmanuel.lepage@kde.org>             *
  *                                                                         *
  *   This program is free software; you can redistribute it and/or modify  *
  *   it under the terms of the GNU General Public License as published by  *
  *   the Free Software Foundation; either version 3 of the License, or     *
  *   (at your option) any later version.                                   *
  *                                                                         *
  *   This program is distributed in the hope that it will be useful,       *
  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  *   GNU General Public License for more details.                          *
  *                                                                         *
  *   You should have received a copy of the GNU General Public License     *
  *   along with this program.  If not, see <http://www.gnu.org/licenses/>. *
  **************************************************************************/
 #ifndef KQUICKITEMVIEWS_INDEX_P_H
 #define KQUICKITEMVIEWS_INDEX_P_H
 
 #include <QtCore/QModelIndex>
 #include <QtCore/QList>
 
 #include <private/geoutils_p.h>
 #include <private/indexmetadata_p.h>
 
 class Viewport;
 
 namespace StateTracker {
 
 class Continuity;
 
 /**
  * Internal navigation structure designed to support partial tree loading.
  *
  * This isn't intended to be used directly. It exists as its own class because
  * previous iterations were embedded within the model event slots and it made
  * it generally unmaintainable. The idea is to provide atomic and batch
  * operations that can be unit tested individually (eventually).
  *
  * * Support continuous but incomplete sets of indices
  * * Support indices currently being moved or removed
  * * Support moving and reparenting
  * * Provide both a geometric/cartesian and tree navigation API.
  */
 class Index
 {
     friend class Continuity; //Manage the m_pContinuity
 public:
     enum class LifeCycleState {
         NEW        , /*!< Not part of a tree yet                              */
         NORMAL     , /*!< There is a valid index and a parent node            */
         TRANSITION , /*!< Between rowsAbouttoMove and rowsMoved (and removed) */
         ROOT       , /*!< This is the root element                            */
     };
 
     explicit Index(Viewport *p) : m_Geometry(this, p) {}
     virtual ~Index();
 
     static void insertChildBefore(Index* self, StateTracker::Index* other, StateTracker::Index* parent);
     static void insertChildAfter(Index* self, StateTracker::Index* other, StateTracker::Index* parent);
 
     Index *firstChild() const;
     Index *lastChild () const;
 
     Index *nextSibling    () const;
     Index *previousSibling() const;
 
     Index *parent() const;
 
     // Geometric navigation
     Index* up   () const; //TODO remove
     Index* down () const; //TODO remove
     Index* left () const; //TODO remove
     Index* right() const; //TODO remove
 
     Index* next(Qt::Edge e) const;
 
     int depth() const;
 
     int effectiveRow() const;
     int effectiveColumn() const;
     QPersistentModelIndex effectiveParentIndex() const;
 
     virtual void remove(bool reparent = false);
     static void bridgeGap(Index* first, StateTracker::Index* second);
 
     Index *childrenLookup(const QPersistentModelIndex &index) const;
     bool hasChildren(Index *child) const;
     int loadedChildrenCount() const;
     QList<Index*> allLoadedChildren() const;
     bool withinRange(QAbstractItemModel* m, int last, int first) const;
 
     void resetTemporaryIndex();
     bool hasTemporaryIndex();
     void setTemporaryIndex(const QModelIndex& newParent, int row, int column);
 
     /** Return true when both elements have the same parent and are continuous.
      * If other is `nullptr` and `i` is first (or last), then that's also true
      */
     bool isNeighbor(Index *other) const;
 
     QPersistentModelIndex index() const;
     void setModelIndex(const QPersistentModelIndex& idx);
 
     LifeCycleState lifeCycleState() const {return m_LifeCycleState;}
 
     IndexMetadata *metadata() const;
 
     //TODO have one for vertical and horizontal axis
     Continuity *continuityTracker() const;
 
     // Runtime tests
 #ifdef ENABLE_EXTRA_VALIDATION
     void _test_validate_chain() const;
     static void _test_bridgeGap(Index *first, Index *second);
 #endif
 
 private:
     // Because slotRowsMoved is called before the change take effect, cache
     // the "new real row and column" since the current index()->row() is now
     // garbage.
     int m_MoveToRow    {-1};
     int m_MoveToColumn {-1};
     QPersistentModelIndex m_MoveToParent;
 
     uint m_Depth {0};
 
     LifeCycleState m_LifeCycleState {LifeCycleState::NEW};
 
     Index* m_tSiblings[2] = {nullptr, nullptr};
     Index* m_tChildren[2] = {nullptr, nullptr};
     // Keep the parent to be able to get back to the root
     Index* m_pParent {nullptr};
     QPersistentModelIndex m_Index;
 
     //TODO use a btree, not an hash
     QHash<QPersistentModelIndex, Index*> m_hLookup;
     mutable IndexMetadata m_Geometry;
     Continuity *m_pContinuity {nullptr};
 };
 
 }
 
 /**
  * TODO get rid of this and implement paging
  *
  * Keep track of state "edges".
  *
  * This allows to manipulate rectangles of QModelIndex similar to QtCore
  * dataChanged and other signals.
  */
 class ModelRect final
 {
 public:
     StateTracker::Index* getEdge(Qt::Edge e) const;
     void setEdge(StateTracker::Index* tti, Qt::Edge e);
 
     Qt::Edges m_Edges {Qt::TopEdge|Qt::LeftEdge|Qt::RightEdge|Qt::BottomEdge};
 private:
     GeoRect<StateTracker::Index*> m_lpEdges; //TODO port to ModelRect
 };
 
 // Inject some extra validation when executed in debug mode.
 #ifdef ENABLE_EXTRA_VALIDATION
  #define _DO_TEST_IDX(f, self, ...) self->f(__VA_ARGS__);
  #define _DO_TEST_IDX_STATIC(f, ...) f(__VA_ARGS__);
 #else
  #define _DO_TEST_IDX(f, self, ...) /*NOP*/;
  #define _DO_TEST_IDX_STATIC(f, ...) /*NOP*/;
 #endif
 
 #endif