File indexing completed on 2024-04-14 14:25:49

 /*
     This file is part of the KDE project
     SPDX-FileCopyrightText: 2007, 2009 Rafael Fernández López <ereslibre@kde.org>
 
     SPDX-License-Identifier: LGPL-2.0-or-later
 */
 
 /**
  * IMPLEMENTATION NOTES:
  *
  * QListView::setRowHidden() and QListView::isRowHidden() are not taken into
  * account. This methods should actually not exist. This effect should be handled
  * by an hypothetical QSortFilterProxyModel which filters out the desired rows.
  *
  * In case this needs to be implemented, contact me, but I consider this a faulty
  * design.
  */
 
 #include "kcategorizedview.h"
 #include "kcategorizedview_p.h"
 
 #include <QPaintEvent>
 #include <QPainter>
 #include <QScrollBar>
 
 #include "kcategorizedsortfilterproxymodel.h"
 #include "kcategorydrawer.h"
 
 // BEGIN: Private part
 
 struct KCategorizedViewPrivate::Item {
     Item()
         : topLeft(QPoint())
         , size(QSize())
     {
     }
 
     QPoint topLeft;
     QSize size;
 };
 
 struct KCategorizedViewPrivate::Block {
     Block()
         : topLeft(QPoint())
         , firstIndex(QModelIndex())
         , quarantineStart(QModelIndex())
         , items(QList<Item>())
     {
     }
 
     bool operator!=(const Block &rhs) const
     {
         return firstIndex != rhs.firstIndex;
     }
 
     static bool lessThan(const Block &left, const Block &right)
     {
         Q_ASSERT(left.firstIndex.isValid());
         Q_ASSERT(right.firstIndex.isValid());
         return left.firstIndex.row() < right.firstIndex.row();
     }
 
     QPoint topLeft;
     int height = -1;
     QPersistentModelIndex firstIndex;
     // if we have n elements on this block, and we inserted an element at position i. The quarantine
     // will start at index (i, column, parent). This means that for all elements j where i <= j <= n, the
     // visual rect position of item j will have to be recomputed (cannot use the cached point). The quarantine
     // will only affect the current block, since the rest of blocks can be affected only in the way
     // that the whole block will have different offset, but items will keep the same relative position
     // in terms of their parent blocks.
     QPersistentModelIndex quarantineStart;
     QList<Item> items;
 
     // this affects the whole block, not items separately. items contain the topLeft point relative
     // to the block. Because of insertions or removals a whole block can be moved, so the whole block
     // will enter in quarantine, what is faster than moving all items in absolute terms.
     bool outOfQuarantine = false;
 
     // should we alternate its color ? is just a hint, could not be used
     bool alternate = false;
     bool collapsed = false;
 };
 
 KCategorizedViewPrivate::KCategorizedViewPrivate(KCategorizedView *qq)
     : q(qq)
     , hoveredBlock(new Block())
     , hoveredIndex(QModelIndex())
     , pressedPosition(QPoint())
     , rubberBandRect(QRect())
 {
 }
 
 KCategorizedViewPrivate::~KCategorizedViewPrivate()
 {
     delete hoveredBlock;
 }
 
 bool KCategorizedViewPrivate::isCategorized() const
 {
     return proxyModel && categoryDrawer && proxyModel->isCategorizedModel();
 }
 
 QStyleOptionViewItem KCategorizedViewPrivate::viewOpts()
 {
 #if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
     QStyleOptionViewItem option;
     q->initViewItemOption(&option);
 #else
     QStyleOptionViewItem option(q->viewOptions());
 #endif
     return option;
 }
 
 QStyleOptionViewItem KCategorizedViewPrivate::blockRect(const QModelIndex &representative)
 {
     QStyleOptionViewItem option = viewOpts();
 
     const int height = categoryDrawer->categoryHeight(representative, option);
     const QString categoryDisplay = representative.data(KCategorizedSortFilterProxyModel::CategoryDisplayRole).toString();
     QPoint pos = blockPosition(categoryDisplay);
     pos.ry() -= height;
     option.rect.setTopLeft(pos);
     option.rect.setWidth(viewportWidth() + categoryDrawer->leftMargin() + categoryDrawer->rightMargin());
     option.rect.setHeight(height + blockHeight(categoryDisplay));
     option.rect = mapToViewport(option.rect);
 
     return option;
 }
 
 std::pair<QModelIndex, QModelIndex> KCategorizedViewPrivate::intersectingIndexesWithRect(const QRect &_rect) const
 {
     const int rowCount = proxyModel->rowCount();
 
     const QRect rect = _rect.normalized();
 
     // binary search to find out the top border
     int bottom = 0;
     int top = rowCount - 1;
     while (bottom <= top) {
         const int middle = (bottom + top) / 2;
         const QModelIndex index = proxyModel->index(middle, q->modelColumn(), q->rootIndex());
         const QRect itemRect = q->visualRect(index);
         if (itemRect.bottomRight().y() <= rect.topLeft().y()) {
             bottom = middle + 1;
         } else {
             top = middle - 1;
         }
     }
 
     const QModelIndex bottomIndex = proxyModel->index(bottom, q->modelColumn(), q->rootIndex());
 
     // binary search to find out the bottom border
     bottom = 0;
     top = rowCount - 1;
     while (bottom <= top) {
         const int middle = (bottom + top) / 2;
         const QModelIndex index = proxyModel->index(middle, q->modelColumn(), q->rootIndex());
         const QRect itemRect = q->visualRect(index);
         if (itemRect.topLeft().y() <= rect.bottomRight().y()) {
             bottom = middle + 1;
         } else {
             top = middle - 1;
         }
     }
 
     const QModelIndex topIndex = proxyModel->index(top, q->modelColumn(), q->rootIndex());
 
     return {bottomIndex, topIndex};
 }
 
 QPoint KCategorizedViewPrivate::blockPosition(const QString &category)
 {
     Block &block = blocks[category];
 
     if (block.outOfQuarantine && !block.topLeft.isNull()) {
         return block.topLeft;
     }
 
     QPoint res(categorySpacing, 0);
 
     const QModelIndex index = block.firstIndex;
 
     for (auto it = blocks.begin(); it != blocks.end(); ++it) {
         Block &block = *it;
         const QModelIndex categoryIndex = block.firstIndex;
         if (index.row() < categoryIndex.row()) {
             continue;
         }
 
         res.ry() += categoryDrawer->categoryHeight(categoryIndex, viewOpts()) + categorySpacing;
         if (index.row() == categoryIndex.row()) {
             continue;
         }
         res.ry() += blockHeight(it.key());
     }
 
     block.outOfQuarantine = true;
     block.topLeft = res;
 
     return res;
 }
 
 int KCategorizedViewPrivate::blockHeight(const QString &category)
 {
     Block &block = blocks[category];
 
     if (block.collapsed) {
         return 0;
     }
 
     if (block.height > -1) {
         return block.height;
     }
 
     const QModelIndex firstIndex = block.firstIndex;
     const QModelIndex lastIndex = proxyModel->index(firstIndex.row() + block.items.count() - 1, q->modelColumn(), q->rootIndex());
     const QRect topLeft = q->visualRect(firstIndex);
     QRect bottomRight = q->visualRect(lastIndex);
 
     if (hasGrid()) {
         bottomRight.setHeight(qMax(bottomRight.height(), q->gridSize().height()));
     } else {
         if (!q->uniformItemSizes()) {
             bottomRight.setHeight(highestElementInLastRow(block) + q->spacing() * 2);
         }
     }
 
     const int height = bottomRight.bottomRight().y() - topLeft.topLeft().y() + 1;
     block.height = height;
 
     return height;
 }
 
 int KCategorizedViewPrivate::viewportWidth() const
 {
     return q->viewport()->width() - categorySpacing * 2 - categoryDrawer->leftMargin() - categoryDrawer->rightMargin();
 }
 
 void KCategorizedViewPrivate::regenerateAllElements()
 {
     for (QHash<QString, Block>::Iterator it = blocks.begin(); it != blocks.end(); ++it) {
         Block &block = *it;
         block.outOfQuarantine = false;
         block.quarantineStart = block.firstIndex;
         block.height = -1;
     }
 }
 
 void KCategorizedViewPrivate::rowsInserted(const QModelIndex &parent, int start, int end)
 {
     if (!isCategorized()) {
         return;
     }
 
     for (int i = start; i <= end; ++i) {
         const QModelIndex index = proxyModel->index(i, q->modelColumn(), parent);
 
         Q_ASSERT(index.isValid());
 
         const QString category = categoryForIndex(index);
 
         Block &block = blocks[category];
 
         // BEGIN: update firstIndex
         // save as firstIndex in block if
         //     - it forced the category creation (first element on this category)
         //     - it is before the first row on that category
         const QModelIndex firstIndex = block.firstIndex;
         if (!firstIndex.isValid() || index.row() < firstIndex.row()) {
             block.firstIndex = index;
         }
         // END: update firstIndex
 
         Q_ASSERT(block.firstIndex.isValid());
 
         const int firstIndexRow = block.firstIndex.row();
 
         block.items.insert(index.row() - firstIndexRow, KCategorizedViewPrivate::Item());
         block.height = -1;
 
         q->visualRect(index);
         q->viewport()->update();
     }
 
     // BEGIN: update the items that are in quarantine in affected categories
     {
         const QModelIndex lastIndex = proxyModel->index(end, q->modelColumn(), parent);
         const QString category = categoryForIndex(lastIndex);
         KCategorizedViewPrivate::Block &block = blocks[category];
         block.quarantineStart = block.firstIndex;
     }
     // END: update the items that are in quarantine in affected categories
 
     // BEGIN: mark as in quarantine those categories that are under the affected ones
     {
         const QModelIndex firstIndex = proxyModel->index(start, q->modelColumn(), parent);
         const QString category = categoryForIndex(firstIndex);
         const QModelIndex firstAffectedCategory = blocks[category].firstIndex;
         // BEGIN: order for marking as alternate those blocks that are alternate
         QList<Block> blockList = blocks.values();
         std::sort(blockList.begin(), blockList.end(), Block::lessThan);
         QList<int> firstIndexesRows;
         for (const Block &block : std::as_const(blockList)) {
             firstIndexesRows << block.firstIndex.row();
         }
         // END: order for marking as alternate those blocks that are alternate
         for (auto it = blocks.begin(); it != blocks.end(); ++it) {
             KCategorizedViewPrivate::Block &block = *it;
             if (block.firstIndex.row() > firstAffectedCategory.row()) {
                 block.outOfQuarantine = false;
                 block.alternate = firstIndexesRows.indexOf(block.firstIndex.row()) % 2;
             } else if (block.firstIndex.row() == firstAffectedCategory.row()) {
                 block.alternate = firstIndexesRows.indexOf(block.firstIndex.row()) % 2;
             }
         }
     }
     // END: mark as in quarantine those categories that are under the affected ones
 }
 
 QRect KCategorizedViewPrivate::mapToViewport(const QRect &rect) const
 {
     const int dx = -q->horizontalOffset();
     const int dy = -q->verticalOffset();
     return rect.adjusted(dx, dy, dx, dy);
 }
 
 QRect KCategorizedViewPrivate::mapFromViewport(const QRect &rect) const
 {
     const int dx = q->horizontalOffset();
     const int dy = q->verticalOffset();
     return rect.adjusted(dx, dy, dx, dy);
 }
 
 int KCategorizedViewPrivate::highestElementInLastRow(const Block &block) const
 {
     // Find the highest element in the last row
     const QModelIndex lastIndex = proxyModel->index(block.firstIndex.row() + block.items.count() - 1, q->modelColumn(), q->rootIndex());
     const QRect prevRect = q->visualRect(lastIndex);
     int res = prevRect.height();
     QModelIndex prevIndex = proxyModel->index(lastIndex.row() - 1, q->modelColumn(), q->rootIndex());
     if (!prevIndex.isValid()) {
         return res;
     }
     Q_FOREVER {
         const QRect tempRect = q->visualRect(prevIndex);
         if (tempRect.topLeft().y() < prevRect.topLeft().y()) {
             break;
         }
         res = qMax(res, tempRect.height());
         if (prevIndex == block.firstIndex) {
             break;
         }
         prevIndex = proxyModel->index(prevIndex.row() - 1, q->modelColumn(), q->rootIndex());
     }
 
     return res;
 }
 
 bool KCategorizedViewPrivate::hasGrid() const
 {
     const QSize gridSize = q->gridSize();
     return gridSize.isValid() && !gridSize.isNull();
 }
 
 QString KCategorizedViewPrivate::categoryForIndex(const QModelIndex &index) const
 {
     const QModelIndex categoryIndex = index.model()->index(index.row(), proxyModel->sortColumn(), index.parent());
     return categoryIndex.data(KCategorizedSortFilterProxyModel::CategoryDisplayRole).toString();
 }
 
 void KCategorizedViewPrivate::leftToRightVisualRect(const QModelIndex &index, Item &item, const Block &block, const QPoint &blockPos) const
 {
     const int firstIndexRow = block.firstIndex.row();
 
     if (hasGrid()) {
         const int relativeRow = index.row() - firstIndexRow;
         const int maxItemsPerRow = qMax(viewportWidth() / q->gridSize().width(), 1);
         if (q->layoutDirection() == Qt::LeftToRight) {
             item.topLeft.rx() = (relativeRow % maxItemsPerRow) * q->gridSize().width() + blockPos.x() + categoryDrawer->leftMargin();
         } else {
             item.topLeft.rx() = viewportWidth() - ((relativeRow % maxItemsPerRow) + 1) * q->gridSize().width() + categoryDrawer->leftMargin() + categorySpacing;
         }
         item.topLeft.ry() = (relativeRow / maxItemsPerRow) * q->gridSize().height();
     } else {
         if (q->uniformItemSizes()) {
             const int relativeRow = index.row() - firstIndexRow;
             const QSize itemSize = q->sizeHintForIndex(index);
             const int maxItemsPerRow = qMax((viewportWidth() - q->spacing()) / (itemSize.width() + q->spacing()), 1);
             if (q->layoutDirection() == Qt::LeftToRight) {
                 item.topLeft.rx() = (relativeRow % maxItemsPerRow) * itemSize.width() + blockPos.x() + categoryDrawer->leftMargin();
             } else {
                 item.topLeft.rx() = viewportWidth() - (relativeRow % maxItemsPerRow) * itemSize.width() + categoryDrawer->leftMargin() + categorySpacing;
             }
             item.topLeft.ry() = (relativeRow / maxItemsPerRow) * itemSize.height();
         } else {
             const QSize currSize = q->sizeHintForIndex(index);
             if (index != block.firstIndex) {
                 const int viewportW = viewportWidth() - q->spacing();
                 QModelIndex prevIndex = proxyModel->index(index.row() - 1, q->modelColumn(), q->rootIndex());
                 QRect prevRect = q->visualRect(prevIndex);
                 prevRect = mapFromViewport(prevRect);
                 if ((prevRect.bottomRight().x() + 1) + currSize.width() - blockPos.x() + q->spacing() > viewportW) {
                     // we have to check the whole previous row, and see which one was the
                     // highest.
                     Q_FOREVER {
                         prevIndex = proxyModel->index(prevIndex.row() - 1, q->modelColumn(), q->rootIndex());
                         const QRect tempRect = q->visualRect(prevIndex);
                         if (tempRect.topLeft().y() < prevRect.topLeft().y()) {
                             break;
                         }
                         if (tempRect.bottomRight().y() > prevRect.bottomRight().y()) {
                             prevRect = tempRect;
                         }
                         if (prevIndex == block.firstIndex) {
                             break;
                         }
                     }
                     if (q->layoutDirection() == Qt::LeftToRight) {
                         item.topLeft.rx() = categoryDrawer->leftMargin() + blockPos.x() + q->spacing();
                     } else {
                         item.topLeft.rx() = viewportWidth() - currSize.width() + categoryDrawer->leftMargin() + categorySpacing;
                     }
                     item.topLeft.ry() = (prevRect.bottomRight().y() + 1) + q->spacing() - blockPos.y();
                 } else {
                     if (q->layoutDirection() == Qt::LeftToRight) {
                         item.topLeft.rx() = (prevRect.bottomRight().x() + 1) + q->spacing();
                     } else {
                         item.topLeft.rx() = (prevRect.bottomLeft().x() - 1) - q->spacing() - item.size.width() + categoryDrawer->leftMargin() + categorySpacing;
                     }
                     item.topLeft.ry() = prevRect.topLeft().y() - blockPos.y();
                 }
             } else {
                 if (q->layoutDirection() == Qt::LeftToRight) {
                     item.topLeft.rx() = blockPos.x() + categoryDrawer->leftMargin() + q->spacing();
                 } else {
                     item.topLeft.rx() = viewportWidth() - currSize.width() + categoryDrawer->leftMargin() + categorySpacing;
                 }
                 item.topLeft.ry() = q->spacing();
             }
         }
     }
     item.size = q->sizeHintForIndex(index);
 }
 
 void KCategorizedViewPrivate::topToBottomVisualRect(const QModelIndex &index, Item &item, const Block &block, const QPoint &blockPos) const
 {
     const int firstIndexRow = block.firstIndex.row();
 
     if (hasGrid()) {
         const int relativeRow = index.row() - firstIndexRow;
         item.topLeft.rx() = blockPos.x() + categoryDrawer->leftMargin();
         item.topLeft.ry() = relativeRow * q->gridSize().height();
     } else {
         if (q->uniformItemSizes()) {
             const int relativeRow = index.row() - firstIndexRow;
             const QSize itemSize = q->sizeHintForIndex(index);
             item.topLeft.rx() = blockPos.x() + categoryDrawer->leftMargin();
             item.topLeft.ry() = relativeRow * itemSize.height();
         } else {
             if (index != block.firstIndex) {
                 QModelIndex prevIndex = proxyModel->index(index.row() - 1, q->modelColumn(), q->rootIndex());
                 QRect prevRect = q->visualRect(prevIndex);
                 prevRect = mapFromViewport(prevRect);
                 item.topLeft.rx() = blockPos.x() + categoryDrawer->leftMargin() + q->spacing();
                 item.topLeft.ry() = (prevRect.bottomRight().y() + 1) + q->spacing() - blockPos.y();
             } else {
                 item.topLeft.rx() = blockPos.x() + categoryDrawer->leftMargin() + q->spacing();
                 item.topLeft.ry() = q->spacing();
             }
         }
     }
     item.size = q->sizeHintForIndex(index);
     item.size.setWidth(viewportWidth());
 }
 
 void KCategorizedViewPrivate::_k_slotCollapseOrExpandClicked(QModelIndex)
 {
 }
 
 // END: Private part
 
 // BEGIN: Public part
 
 KCategorizedView::KCategorizedView(QWidget *parent)
     : QListView(parent)
     , d(new KCategorizedViewPrivate(this))
 {
 }
 
 KCategorizedView::~KCategorizedView() = default;
 
 void KCategorizedView::setModel(QAbstractItemModel *model)
 {
     if (d->proxyModel == model) {
         return;
     }
 
     d->blocks.clear();
 
     if (d->proxyModel) {
         disconnect(d->proxyModel, SIGNAL(layoutChanged()), this, SLOT(slotLayoutChanged()));
     }
 
     d->proxyModel = dynamic_cast<KCategorizedSortFilterProxyModel *>(model);
 
     if (d->proxyModel) {
         connect(d->proxyModel, SIGNAL(layoutChanged()), this, SLOT(slotLayoutChanged()));
     }
 
     QListView::setModel(model);
 
     // if the model already had information inserted, update our data structures to it
     if (model->rowCount()) {
         slotLayoutChanged();
     }
 }
 
 void KCategorizedView::setGridSize(const QSize &size)
 {
     setGridSizeOwn(size);
 }
 
 void KCategorizedView::setGridSizeOwn(const QSize &size)
 {
     d->regenerateAllElements();
     QListView::setGridSize(size);
 }
 
 QRect KCategorizedView::visualRect(const QModelIndex &index) const
 {
     if (!d->isCategorized()) {
         return QListView::visualRect(index);
     }
 
     if (!index.isValid()) {
         return QRect();
     }
 
     const QString category = d->categoryForIndex(index);
 
     if (!d->blocks.contains(category)) {
         return QRect();
     }
 
     KCategorizedViewPrivate::Block &block = d->blocks[category];
     const int firstIndexRow = block.firstIndex.row();
 
     Q_ASSERT(block.firstIndex.isValid());
 
     if (index.row() - firstIndexRow < 0 || index.row() - firstIndexRow >= block.items.count()) {
         return QRect();
     }
 
     const QPoint blockPos = d->blockPosition(category);
 
     KCategorizedViewPrivate::Item &ritem = block.items[index.row() - firstIndexRow];
 
     if (ritem.topLeft.isNull() //
         || (block.quarantineStart.isValid() && index.row() >= block.quarantineStart.row())) {
         if (flow() == LeftToRight) {
             d->leftToRightVisualRect(index, ritem, block, blockPos);
         } else {
             d->topToBottomVisualRect(index, ritem, block, blockPos);
         }
 
         // BEGIN: update the quarantine start
         const bool wasLastIndex = (index.row() == (block.firstIndex.row() + block.items.count() - 1));
         if (index.row() == block.quarantineStart.row()) {
             if (wasLastIndex) {
                 block.quarantineStart = QModelIndex();
             } else {
                 const QModelIndex nextIndex = d->proxyModel->index(index.row() + 1, modelColumn(), rootIndex());
                 block.quarantineStart = nextIndex;
             }
         }
         // END: update the quarantine start
     }
 
     // we get now the absolute position through the relative position of the parent block. do not
     // save this on ritem, since this would override the item relative position in block terms.
     KCategorizedViewPrivate::Item item(ritem);
     item.topLeft.ry() += blockPos.y();
 
     const QSize sizeHint = item.size;
 
     if (d->hasGrid()) {
         const QSize sizeGrid = gridSize();
         const QSize resultingSize = sizeHint.boundedTo(sizeGrid);
         QRect res(item.topLeft.x() + ((sizeGrid.width() - resultingSize.width()) / 2), item.topLeft.y(), resultingSize.width(), resultingSize.height());
         if (block.collapsed) {
             // we can still do binary search, while we "hide" items. We move those items in collapsed
             // blocks to the left and set a 0 height.
             res.setLeft(-resultingSize.width());
             res.setHeight(0);
         }
         return d->mapToViewport(res);
     }
 
     QRect res(item.topLeft.x(), item.topLeft.y(), sizeHint.width(), sizeHint.height());
     if (block.collapsed) {
         // we can still do binary search, while we "hide" items. We move those items in collapsed
         // blocks to the left and set a 0 height.
         res.setLeft(-sizeHint.width());
         res.setHeight(0);
     }
     return d->mapToViewport(res);
 }
 
 KCategoryDrawer *KCategorizedView::categoryDrawer() const
 {
     return d->categoryDrawer;
 }
 
 void KCategorizedView::setCategoryDrawer(KCategoryDrawer *categoryDrawer)
 {
     if (d->categoryDrawer) {
         disconnect(d->categoryDrawer, SIGNAL(collapseOrExpandClicked(QModelIndex)), this, SLOT(_k_slotCollapseOrExpandClicked(QModelIndex)));
     }
 
     d->categoryDrawer = categoryDrawer;
 
     connect(d->categoryDrawer, SIGNAL(collapseOrExpandClicked(QModelIndex)), this, SLOT(_k_slotCollapseOrExpandClicked(QModelIndex)));
 }
 
 int KCategorizedView::categorySpacing() const
 {
     return d->categorySpacing;
 }
 
 void KCategorizedView::setCategorySpacing(int categorySpacing)
 {
     if (d->categorySpacing == categorySpacing) {
         return;
     }
 
     d->categorySpacing = categorySpacing;
 
     for (auto it = d->blocks.begin(); it != d->blocks.end(); ++it) {
         KCategorizedViewPrivate::Block &block = *it;
         block.outOfQuarantine = false;
     }
 }
 
 bool KCategorizedView::alternatingBlockColors() const
 {
     return d->alternatingBlockColors;
 }
 
 void KCategorizedView::setAlternatingBlockColors(bool enable)
 {
     d->alternatingBlockColors = enable;
 }
 
 bool KCategorizedView::collapsibleBlocks() const
 {
     return d->collapsibleBlocks;
 }
 
 void KCategorizedView::setCollapsibleBlocks(bool enable)
 {
     d->collapsibleBlocks = enable;
 }
 
 QModelIndexList KCategorizedView::block(const QString &category)
 {
     QModelIndexList res;
     const KCategorizedViewPrivate::Block &block = d->blocks[category];
     if (block.height == -1) {
         return res;
     }
     QModelIndex current = block.firstIndex;
     const int first = current.row();
     for (int i = 1; i <= block.items.count(); ++i) {
         if (current.isValid()) {
             res << current;
         }
         current = d->proxyModel->index(first + i, modelColumn(), rootIndex());
     }
     return res;
 }
 
 QModelIndexList KCategorizedView::block(const QModelIndex &representative)
 {
     return block(representative.data(KCategorizedSortFilterProxyModel::CategoryDisplayRole).toString());
 }
 
 QModelIndex KCategorizedView::indexAt(const QPoint &point) const
 {
     if (!d->isCategorized()) {
         return QListView::indexAt(point);
     }
 
     const int rowCount = d->proxyModel->rowCount();
     if (!rowCount) {
         return QModelIndex();
     }
 
     // Binary search that will try to spot if there is an index under point
     int bottom = 0;
     int top = rowCount - 1;
     while (bottom <= top) {
         const int middle = (bottom + top) / 2;
         const QModelIndex index = d->proxyModel->index(middle, modelColumn(), rootIndex());
         const QRect rect = visualRect(index);
         if (rect.contains(point)) {
             if (index.model()->flags(index) & Qt::ItemIsEnabled) {
                 return index;
             }
             return QModelIndex();
         }
         bool directionCondition;
         if (layoutDirection() == Qt::LeftToRight) {
             directionCondition = point.x() >= rect.bottomLeft().x();
         } else {
             directionCondition = point.x() <= rect.bottomRight().x();
         }
         if (point.y() < rect.topLeft().y()) {
             top = middle - 1;
         } else if (directionCondition) {
             bottom = middle + 1;
         } else if (point.y() <= rect.bottomRight().y()) {
             top = middle - 1;
         } else {
             bool after = true;
             for (int i = middle - 1; i >= bottom; i--) {
                 const QModelIndex newIndex = d->proxyModel->index(i, modelColumn(), rootIndex());
                 const QRect newRect = visualRect(newIndex);
                 if (newRect.topLeft().y() < rect.topLeft().y()) {
                     break;
                 } else if (newRect.contains(point)) {
                     if (newIndex.model()->flags(newIndex) & Qt::ItemIsEnabled) {
                         return newIndex;
                     }
                     return QModelIndex();
                     // clang-format off
                 } else if ((layoutDirection() == Qt::LeftToRight) ?
                            (newRect.topLeft().x() <= point.x()) :
                            (newRect.topRight().x() >= point.x())) {
                     // clang-format on
                     break;
                 } else if (newRect.bottomRight().y() >= point.y()) {
                     after = false;
                 }
             }
             if (!after) {
                 return QModelIndex();
             }
             bottom = middle + 1;
         }
     }
     return QModelIndex();
 }
 
 void KCategorizedView::reset()
 {
     d->blocks.clear();
     QListView::reset();
 }
 
 void KCategorizedView::paintEvent(QPaintEvent *event)
 {
     if (!d->isCategorized()) {
         QListView::paintEvent(event);
         return;
     }
 
     const std::pair<QModelIndex, QModelIndex> intersecting = d->intersectingIndexesWithRect(viewport()->rect().intersected(event->rect()));
 
     QPainter p(viewport());
     p.save();
 
     Q_ASSERT(selectionModel()->model() == d->proxyModel);
 
     // BEGIN: draw categories
     auto it = d->blocks.constBegin();
     while (it != d->blocks.constEnd()) {
         const KCategorizedViewPrivate::Block &block = *it;
         const QModelIndex categoryIndex = d->proxyModel->index(block.firstIndex.row(), d->proxyModel->sortColumn(), rootIndex());
 
         QStyleOptionViewItem option = d->viewOpts();
         option.features |= d->alternatingBlockColors && block.alternate //
             ? QStyleOptionViewItem::Alternate
             : QStyleOptionViewItem::None;
         option.state |= !d->collapsibleBlocks || !block.collapsed //
             ? QStyle::State_Open
             : QStyle::State_None;
         const int height = d->categoryDrawer->categoryHeight(categoryIndex, option);
         QPoint pos = d->blockPosition(it.key());
         pos.ry() -= height;
         option.rect.setTopLeft(pos);
         option.rect.setWidth(d->viewportWidth() + d->categoryDrawer->leftMargin() + d->categoryDrawer->rightMargin());
         option.rect.setHeight(height + d->blockHeight(it.key()));
         option.rect = d->mapToViewport(option.rect);
         if (!option.rect.intersects(viewport()->rect())) {
             ++it;
             continue;
         }
         d->categoryDrawer->drawCategory(categoryIndex, d->proxyModel->sortRole(), option, &p);
         ++it;
     }
     // END: draw categories
 
     if (intersecting.first.isValid() && intersecting.second.isValid()) {
         // BEGIN: draw items
         int i = intersecting.first.row();
         int indexToCheckIfBlockCollapsed = i;
         QModelIndex categoryIndex;
         QString category;
         KCategorizedViewPrivate::Block *block = nullptr;
         while (i <= intersecting.second.row()) {
             // BEGIN: first check if the block is collapsed. if so, we have to skip the item painting
             if (i == indexToCheckIfBlockCollapsed) {
                 categoryIndex = d->proxyModel->index(i, d->proxyModel->sortColumn(), rootIndex());
                 category = categoryIndex.data(KCategorizedSortFilterProxyModel::CategoryDisplayRole).toString();
                 block = &d->blocks[category];
                 indexToCheckIfBlockCollapsed = block->firstIndex.row() + block->items.count();
                 if (block->collapsed) {
                     i = indexToCheckIfBlockCollapsed;
                     continue;
                 }
             }
             // END: first check if the block is collapsed. if so, we have to skip the item painting
 
             Q_ASSERT(block);
 
             const bool alternateItem = (i - block->firstIndex.row()) % 2;
 
             const QModelIndex index = d->proxyModel->index(i, modelColumn(), rootIndex());
             const Qt::ItemFlags flags = d->proxyModel->flags(index);
             QStyleOptionViewItem option(d->viewOpts());
             option.rect = visualRect(index);
             option.widget = this;
             option.features |= wordWrap() ? QStyleOptionViewItem::WrapText : QStyleOptionViewItem::None;
             option.features |= alternatingRowColors() && alternateItem ? QStyleOptionViewItem::Alternate : QStyleOptionViewItem::None;
             if (flags & Qt::ItemIsSelectable) {
                 option.state |= selectionModel()->isSelected(index) ? QStyle::State_Selected : QStyle::State_None;
             } else {
                 option.state &= ~QStyle::State_Selected;
             }
             option.state |= (index == currentIndex()) ? QStyle::State_HasFocus : QStyle::State_None;
             if (!(flags & Qt::ItemIsEnabled)) {
                 option.state &= ~QStyle::State_Enabled;
             } else {
                 option.state |= (index == d->hoveredIndex) ? QStyle::State_MouseOver : QStyle::State_None;
             }
 
             itemDelegate(index)->paint(&p, option, index);
             ++i;
         }
         // END: draw items
     }
 
     // BEGIN: draw selection rect
     if (isSelectionRectVisible() && d->rubberBandRect.isValid()) {
         QStyleOptionRubberBand opt;
         opt.initFrom(this);
         opt.shape = QRubberBand::Rectangle;
         opt.opaque = false;
         opt.rect = d->mapToViewport(d->rubberBandRect).intersected(viewport()->rect().adjusted(-16, -16, 16, 16));
         p.save();
         style()->drawControl(QStyle::CE_RubberBand, &opt, &p);
         p.restore();
     }
     // END: draw selection rect
 
     p.restore();
 }
 
 void KCategorizedView::resizeEvent(QResizeEvent *event)
 {
     d->regenerateAllElements();
     QListView::resizeEvent(event);
 }
 
 void KCategorizedView::setSelection(const QRect &rect, QItemSelectionModel::SelectionFlags flags)
 {
     if (!d->isCategorized()) {
         QListView::setSelection(rect, flags);
         return;
     }
 
     if (rect.topLeft() == rect.bottomRight()) {
         const QModelIndex index = indexAt(rect.topLeft());
         selectionModel()->select(index, flags);
         return;
     }
 
     const std::pair<QModelIndex, QModelIndex> intersecting = d->intersectingIndexesWithRect(rect);
 
     QItemSelection selection;
 
     // TODO: think of a faster implementation
     QModelIndex firstIndex;
     QModelIndex lastIndex;
     for (int i = intersecting.first.row(); i <= intersecting.second.row(); ++i) {
         const QModelIndex index = d->proxyModel->index(i, modelColumn(), rootIndex());
         const bool visualRectIntersects = visualRect(index).intersects(rect);
         if (firstIndex.isValid()) {
             if (visualRectIntersects) {
                 lastIndex = index;
             } else {
                 selection << QItemSelectionRange(firstIndex, lastIndex);
                 firstIndex = QModelIndex();
             }
         } else if (visualRectIntersects) {
             firstIndex = index;
             lastIndex = index;
         }
     }
 
     if (firstIndex.isValid()) {
         selection << QItemSelectionRange(firstIndex, lastIndex);
     }
 
     selectionModel()->select(selection, flags);
 }
 
 void KCategorizedView::mouseMoveEvent(QMouseEvent *event)
 {
     QListView::mouseMoveEvent(event);
     d->hoveredIndex = indexAt(event->pos());
     const SelectionMode itemViewSelectionMode = selectionMode();
     if (state() == DragSelectingState //
         && isSelectionRectVisible() //
         && itemViewSelectionMode != SingleSelection //
         && itemViewSelectionMode != NoSelection) {
         QRect rect(d->pressedPosition, event->pos() + QPoint(horizontalOffset(), verticalOffset()));
         rect = rect.normalized();
         update(rect.united(d->rubberBandRect));
         d->rubberBandRect = rect;
     }
     if (!d->categoryDrawer) {
         return;
     }
     auto it = d->blocks.constBegin();
     while (it != d->blocks.constEnd()) {
         const KCategorizedViewPrivate::Block &block = *it;
         const QModelIndex categoryIndex = d->proxyModel->index(block.firstIndex.row(), d->proxyModel->sortColumn(), rootIndex());
         QStyleOptionViewItem option(d->viewOpts());
         const int height = d->categoryDrawer->categoryHeight(categoryIndex, option);
         QPoint pos = d->blockPosition(it.key());
         pos.ry() -= height;
         option.rect.setTopLeft(pos);
         option.rect.setWidth(d->viewportWidth() + d->categoryDrawer->leftMargin() + d->categoryDrawer->rightMargin());
         option.rect.setHeight(height + d->blockHeight(it.key()));
         option.rect = d->mapToViewport(option.rect);
         const QPoint mousePos = viewport()->mapFromGlobal(QCursor::pos());
         if (option.rect.contains(mousePos)) {
             if (d->hoveredBlock->height != -1 && *d->hoveredBlock != block) {
                 const QModelIndex categoryIndex = d->proxyModel->index(d->hoveredBlock->firstIndex.row(), d->proxyModel->sortColumn(), rootIndex());
                 const QStyleOptionViewItem option = d->blockRect(categoryIndex);
                 d->categoryDrawer->mouseLeft(categoryIndex, option.rect);
                 *d->hoveredBlock = block;
                 d->hoveredCategory = it.key();
                 viewport()->update(option.rect);
             } else if (d->hoveredBlock->height == -1) {
                 *d->hoveredBlock = block;
                 d->hoveredCategory = it.key();
             } else {
                 d->categoryDrawer->mouseMoved(categoryIndex, option.rect, event);
             }
             viewport()->update(option.rect);
             return;
         }
         ++it;
     }
     if (d->hoveredBlock->height != -1) {
         const QModelIndex categoryIndex = d->proxyModel->index(d->hoveredBlock->firstIndex.row(), d->proxyModel->sortColumn(), rootIndex());
         const QStyleOptionViewItem option = d->blockRect(categoryIndex);
         d->categoryDrawer->mouseLeft(categoryIndex, option.rect);
         *d->hoveredBlock = KCategorizedViewPrivate::Block();
         d->hoveredCategory = QString();
         viewport()->update(option.rect);
     }
 }
 
 void KCategorizedView::mousePressEvent(QMouseEvent *event)
 {
     if (event->button() == Qt::LeftButton) {
         d->pressedPosition = event->pos();
         d->pressedPosition.rx() += horizontalOffset();
         d->pressedPosition.ry() += verticalOffset();
     }
     if (!d->categoryDrawer) {
         QListView::mousePressEvent(event);
         return;
     }
     auto it = d->blocks.constBegin();
     while (it != d->blocks.constEnd()) {
         const KCategorizedViewPrivate::Block &block = *it;
         const QModelIndex categoryIndex = d->proxyModel->index(block.firstIndex.row(), d->proxyModel->sortColumn(), rootIndex());
         const QStyleOptionViewItem option = d->blockRect(categoryIndex);
         const QPoint mousePos = viewport()->mapFromGlobal(QCursor::pos());
         if (option.rect.contains(mousePos)) {
             d->categoryDrawer->mouseButtonPressed(categoryIndex, option.rect, event);
             viewport()->update(option.rect);
             if (!event->isAccepted()) {
                 QListView::mousePressEvent(event);
             }
             return;
         }
         ++it;
     }
     QListView::mousePressEvent(event);
 }
 
 void KCategorizedView::mouseReleaseEvent(QMouseEvent *event)
 {
     d->pressedPosition = QPoint();
     d->rubberBandRect = QRect();
     if (!d->categoryDrawer) {
         QListView::mouseReleaseEvent(event);
         return;
     }
     auto it = d->blocks.constBegin();
     while (it != d->blocks.constEnd()) {
         const KCategorizedViewPrivate::Block &block = *it;
         const QModelIndex categoryIndex = d->proxyModel->index(block.firstIndex.row(), d->proxyModel->sortColumn(), rootIndex());
         const QStyleOptionViewItem option = d->blockRect(categoryIndex);
         const QPoint mousePos = viewport()->mapFromGlobal(QCursor::pos());
         if (option.rect.contains(mousePos)) {
             d->categoryDrawer->mouseButtonReleased(categoryIndex, option.rect, event);
             viewport()->update(option.rect);
             if (!event->isAccepted()) {
                 QListView::mouseReleaseEvent(event);
             }
             return;
         }
         ++it;
     }
     QListView::mouseReleaseEvent(event);
 }
 
 void KCategorizedView::leaveEvent(QEvent *event)
 {
     QListView::leaveEvent(event);
     if (d->hoveredIndex.isValid()) {
         viewport()->update(visualRect(d->hoveredIndex));
         d->hoveredIndex = QModelIndex();
     }
     if (d->categoryDrawer && d->hoveredBlock->height != -1) {
         const QModelIndex categoryIndex = d->proxyModel->index(d->hoveredBlock->firstIndex.row(), d->proxyModel->sortColumn(), rootIndex());
         const QStyleOptionViewItem option = d->blockRect(categoryIndex);
         d->categoryDrawer->mouseLeft(categoryIndex, option.rect);
         *d->hoveredBlock = KCategorizedViewPrivate::Block();
         d->hoveredCategory = QString();
         viewport()->update(option.rect);
     }
 }
 
 void KCategorizedView::startDrag(Qt::DropActions supportedActions)
 {
     QListView::startDrag(supportedActions);
 }
 
 void KCategorizedView::dragMoveEvent(QDragMoveEvent *event)
 {
     QListView::dragMoveEvent(event);
     d->hoveredIndex = indexAt(event->pos());
 }
 
 void KCategorizedView::dragEnterEvent(QDragEnterEvent *event)
 {
     QListView::dragEnterEvent(event);
 }
 
 void KCategorizedView::dragLeaveEvent(QDragLeaveEvent *event)
 {
     QListView::dragLeaveEvent(event);
 }
 
 void KCategorizedView::dropEvent(QDropEvent *event)
 {
     QListView::dropEvent(event);
 }
 
 // TODO: improve se we take into account collapsed blocks
 // TODO: take into account when there is no grid and no uniformItemSizes
 QModelIndex KCategorizedView::moveCursor(CursorAction cursorAction, Qt::KeyboardModifiers modifiers)
 {
     if (!d->isCategorized() || viewMode() == QListView::ListMode) {
         return QListView::moveCursor(cursorAction, modifiers);
     }
 
     const QModelIndex current = currentIndex();
     const QRect currentRect = visualRect(current);
     if (!current.isValid()) {
         const int rowCount = d->proxyModel->rowCount(rootIndex());
         if (!rowCount) {
             return QModelIndex();
         }
         return d->proxyModel->index(0, modelColumn(), rootIndex());
     }
 
     switch (cursorAction) {
     case MoveLeft: {
         if (!current.row()) {
             return QModelIndex();
         }
         const QModelIndex previous = d->proxyModel->index(current.row() - 1, modelColumn(), rootIndex());
         const QRect previousRect = visualRect(previous);
         if (previousRect.top() == currentRect.top()) {
             return previous;
         }
 
         return QModelIndex();
     }
     case MoveRight: {
         if (current.row() == d->proxyModel->rowCount() - 1) {
             return QModelIndex();
         }
         const QModelIndex next = d->proxyModel->index(current.row() + 1, modelColumn(), rootIndex());
         const QRect nextRect = visualRect(next);
         if (nextRect.top() == currentRect.top()) {
             return next;
         }
 
         return QModelIndex();
     }
     case MoveDown: {
         if (d->hasGrid() || uniformItemSizes()) {
             const QModelIndex current = currentIndex();
             const QSize itemSize = d->hasGrid() ? gridSize() : sizeHintForIndex(current);
             const KCategorizedViewPrivate::Block &block = d->blocks[d->categoryForIndex(current)];
             const int maxItemsPerRow = qMax(d->viewportWidth() / itemSize.width(), 1);
             const bool canMove = current.row() + maxItemsPerRow < block.firstIndex.row() + block.items.count();
 
             if (canMove) {
                 return d->proxyModel->index(current.row() + maxItemsPerRow, modelColumn(), rootIndex());
             }
 
             const int currentRelativePos = (current.row() - block.firstIndex.row()) % maxItemsPerRow;
             const QModelIndex nextIndex = d->proxyModel->index(block.firstIndex.row() + block.items.count(), modelColumn(), rootIndex());
 
             if (!nextIndex.isValid()) {
                 return QModelIndex();
             }
 
             const KCategorizedViewPrivate::Block &nextBlock = d->blocks[d->categoryForIndex(nextIndex)];
 
             if (nextBlock.items.count() <= currentRelativePos) {
                 return QModelIndex();
             }
 
             if (currentRelativePos < (block.items.count() % maxItemsPerRow)) {
                 return d->proxyModel->index(nextBlock.firstIndex.row() + currentRelativePos, modelColumn(), rootIndex());
             }
         }
         return QModelIndex();
     }
     case MoveUp: {
         if (d->hasGrid() || uniformItemSizes()) {
             const QModelIndex current = currentIndex();
             const QSize itemSize = d->hasGrid() ? gridSize() : sizeHintForIndex(current);
             const KCategorizedViewPrivate::Block &block = d->blocks[d->categoryForIndex(current)];
             const int maxItemsPerRow = qMax(d->viewportWidth() / itemSize.width(), 1);
             const bool canMove = current.row() - maxItemsPerRow >= block.firstIndex.row();
 
             if (canMove) {
                 return d->proxyModel->index(current.row() - maxItemsPerRow, modelColumn(), rootIndex());
             }
 
             const int currentRelativePos = (current.row() - block.firstIndex.row()) % maxItemsPerRow;
             const QModelIndex prevIndex = d->proxyModel->index(block.firstIndex.row() - 1, modelColumn(), rootIndex());
 
             if (!prevIndex.isValid()) {
                 return QModelIndex();
             }
 
             const KCategorizedViewPrivate::Block &prevBlock = d->blocks[d->categoryForIndex(prevIndex)];
 
             if (prevBlock.items.count() <= currentRelativePos) {
                 return QModelIndex();
             }
 
             const int remainder = prevBlock.items.count() % maxItemsPerRow;
             if (currentRelativePos < remainder) {
                 return d->proxyModel->index(prevBlock.firstIndex.row() + prevBlock.items.count() - remainder + currentRelativePos, modelColumn(), rootIndex());
             }
 
             return QModelIndex();
         }
         break;
     }
     default:
         break;
     }
 
     return QModelIndex();
 }
 
 void KCategorizedView::rowsAboutToBeRemoved(const QModelIndex &parent, int start, int end)
 {
     if (!d->isCategorized()) {
         QListView::rowsAboutToBeRemoved(parent, start, end);
         return;
     }
 
     *d->hoveredBlock = KCategorizedViewPrivate::Block();
     d->hoveredCategory = QString();
 
     if (end - start + 1 == d->proxyModel->rowCount()) {
         d->blocks.clear();
         QListView::rowsAboutToBeRemoved(parent, start, end);
         return;
     }
 
     // Removal feels a bit more complicated than insertion. Basically we can consider there are
     // 3 different cases when going to remove items. (*) represents an item, Items between ([) and
     // (]) are the ones which are marked for removal.
     //
     // - 1st case:
     //              ... * * * * * * [ * * * ...
     //
     //   The items marked for removal are the last part of this category. No need to mark any item
     //   of this category as in quarantine, because no special offset will be pushed to items at
     //   the right because of any changes (since the removed items are those on the right most part
     //   of the category).
     //
     // - 2nd case:
     //              ... * * * * * * ] * * * ...
     //
     //   The items marked for removal are the first part of this category. We have to mark as in
     //   quarantine all items in this category. Absolutely all. All items will have to be moved to
     //   the left (or moving up, because rows got a different offset).
     //
     // - 3rd case:
     //              ... * * [ * * * * ] * * ...
     //
     //   The items marked for removal are in between of this category. We have to mark as in
     //   quarantine only those items that are at the right of the end of the removal interval,
     //   (starting on "]").
     //
     // It hasn't been explicitly said, but when we remove, we have to mark all blocks that are
     // located under the top most affected category as in quarantine (the block itself, as a whole),
     // because such a change can force it to have a different offset (note that items themselves
     // contain relative positions to the block, so marking the block as in quarantine is enough).
     //
     // Also note that removal implicitly means that we have to update correctly firstIndex of each
     // block, and in general keep updated the internal information of elements.
 
     QStringList listOfCategoriesMarkedForRemoval;
 
     QString lastCategory;
     int alreadyRemoved = 0;
     for (int i = start; i <= end; ++i) {
         const QModelIndex index = d->proxyModel->index(i, modelColumn(), parent);
 
         Q_ASSERT(index.isValid());
 
         const QString category = d->categoryForIndex(index);
 
         if (lastCategory != category) {
             lastCategory = category;
             alreadyRemoved = 0;
         }
 
         KCategorizedViewPrivate::Block &block = d->blocks[category];
         block.items.removeAt(i - block.firstIndex.row() - alreadyRemoved);
         ++alreadyRemoved;
 
         if (block.items.isEmpty()) {
             listOfCategoriesMarkedForRemoval << category;
         }
 
         block.height = -1;
 
         viewport()->update();
     }
 
     // BEGIN: update the items that are in quarantine in affected categories
     {
         const QModelIndex lastIndex = d->proxyModel->index(end, modelColumn(), parent);
         const QString category = d->categoryForIndex(lastIndex);
         KCategorizedViewPrivate::Block &block = d->blocks[category];
         if (!block.items.isEmpty() && start <= block.firstIndex.row() && end >= block.firstIndex.row()) {
             block.firstIndex = d->proxyModel->index(end + 1, modelColumn(), parent);
         }
         block.quarantineStart = block.firstIndex;
     }
     // END: update the items that are in quarantine in affected categories
 
     for (const QString &category : std::as_const(listOfCategoriesMarkedForRemoval)) {
         d->blocks.remove(category);
     }
 
     // BEGIN: mark as in quarantine those categories that are under the affected ones
     {
         // BEGIN: order for marking as alternate those blocks that are alternate
         QList<KCategorizedViewPrivate::Block> blockList = d->blocks.values();
         std::sort(blockList.begin(), blockList.end(), KCategorizedViewPrivate::Block::lessThan);
         QList<int> firstIndexesRows;
         for (const KCategorizedViewPrivate::Block &block : std::as_const(blockList)) {
             firstIndexesRows << block.firstIndex.row();
         }
         // END: order for marking as alternate those blocks that are alternate
         for (auto it = d->blocks.begin(); it != d->blocks.end(); ++it) {
             KCategorizedViewPrivate::Block &block = *it;
             if (block.firstIndex.row() > start) {
                 block.outOfQuarantine = false;
                 block.alternate = firstIndexesRows.indexOf(block.firstIndex.row()) % 2;
             } else if (block.firstIndex.row() == start) {
                 block.alternate = firstIndexesRows.indexOf(block.firstIndex.row()) % 2;
             }
         }
     }
     // END: mark as in quarantine those categories that are under the affected ones
 
     QListView::rowsAboutToBeRemoved(parent, start, end);
 }
 
 void KCategorizedView::updateGeometries()
 {
     const int oldVerticalOffset = verticalOffset();
     const Qt::ScrollBarPolicy verticalP = verticalScrollBarPolicy();
     const Qt::ScrollBarPolicy horizontalP = horizontalScrollBarPolicy();
 
     // BEGIN bugs 213068, 287847 ------------------------------------------------------------
     /*
      * QListView::updateGeometries() has it's own opinion on whether the scrollbars should be visible (valid range) or not
      * and triggers a (sometimes additionally timered) resize through ::layoutChildren()
      * http://qt.gitorious.org/qt/qt/blobs/4.7/src/gui/itemviews/qlistview.cpp#line1499
      * (the comment above the main block isn't all accurate, layoutChldren is called regardless of the policy)
      *
      * As a result QListView and KCategorizedView occasionally started a race on the scrollbar visibility, effectively blocking the UI
      * So we prevent QListView from having an own opinion on the scrollbar visibility by
      * fixing it before calling the baseclass QListView::updateGeometries()
      *
      * Since the implicit show/hide by the following range setting will cause further resizes if the policy is Qt::ScrollBarAsNeeded
      * we keep it static until we're done, then restore the original value and ultimately change the scrollbar visibility ourself.
      */
     if (d->isCategorized()) { // important! - otherwise we'd pollute the setting if the view is initially not categorized
         setVerticalScrollBarPolicy((verticalP == Qt::ScrollBarAlwaysOn || verticalScrollBar()->isVisibleTo(this)) ? Qt::ScrollBarAlwaysOn
                                                                                                                   : Qt::ScrollBarAlwaysOff);
         setHorizontalScrollBarPolicy((horizontalP == Qt::ScrollBarAlwaysOn || horizontalScrollBar()->isVisibleTo(this)) ? Qt::ScrollBarAlwaysOn
                                                                                                                         : Qt::ScrollBarAlwaysOff);
     }
     // END bugs 213068, 287847 --------------------------------------------------------------
 
     QListView::updateGeometries();
 
     if (!d->isCategorized()) {
         return;
     }
 
     const int rowCount = d->proxyModel->rowCount();
     if (!rowCount) {
         verticalScrollBar()->setRange(0, 0);
         // unconditional, see function end todo
         // BEGIN bugs 213068, 287847 ------------------------------------------------------------
         // restoring values from above ...
         horizontalScrollBar()->setRange(0, 0);
         setVerticalScrollBarPolicy(verticalP);
         setHorizontalScrollBarPolicy(horizontalP);
         // END bugs 213068, 287847 --------------------------------------------------------------
         return;
     }
 
     const QModelIndex lastIndex = d->proxyModel->index(rowCount - 1, modelColumn(), rootIndex());
     Q_ASSERT(lastIndex.isValid());
     QRect lastItemRect = visualRect(lastIndex);
 
     if (d->hasGrid()) {
         lastItemRect.setSize(lastItemRect.size().expandedTo(gridSize()));
     } else {
         if (uniformItemSizes()) {
             QSize itemSize = sizeHintForIndex(lastIndex);
             itemSize.setHeight(itemSize.height() + spacing());
             lastItemRect.setSize(itemSize);
         } else {
             QSize itemSize = sizeHintForIndex(lastIndex);
             const QString category = d->categoryForIndex(lastIndex);
             itemSize.setHeight(d->highestElementInLastRow(d->blocks[category]) + spacing());
             lastItemRect.setSize(itemSize);
         }
     }
 
     const int bottomRange = lastItemRect.bottomRight().y() + verticalOffset() - viewport()->height();
 
     if (verticalScrollMode() == ScrollPerItem) {
         verticalScrollBar()->setSingleStep(lastItemRect.height());
         const int rowsPerPage = qMax(viewport()->height() / lastItemRect.height(), 1);
         verticalScrollBar()->setPageStep(rowsPerPage * lastItemRect.height());
     }
 
     verticalScrollBar()->setRange(0, bottomRange);
     verticalScrollBar()->setValue(oldVerticalOffset);
 
     // TODO: also consider working with the horizontal scroll bar. since at this level I am not still
     //      supporting "top to bottom" flow, there is no real problem. If I support that someday
     //      (think how to draw categories), we would have to take care of the horizontal scroll bar too.
     //      In theory, as KCategorizedView has been designed, there is no need of horizontal scroll bar.
     horizontalScrollBar()->setRange(0, 0);
 
     // BEGIN bugs 213068, 287847 ------------------------------------------------------------
     // restoring values from above ...
     setVerticalScrollBarPolicy(verticalP);
     setHorizontalScrollBarPolicy(horizontalP);
     // ... and correct the visibility
     bool validRange = verticalScrollBar()->maximum() != verticalScrollBar()->minimum();
     if (verticalP == Qt::ScrollBarAsNeeded && (verticalScrollBar()->isVisibleTo(this) != validRange)) {
         verticalScrollBar()->setVisible(validRange);
     }
     validRange = horizontalScrollBar()->maximum() > horizontalScrollBar()->minimum();
     if (horizontalP == Qt::ScrollBarAsNeeded && (horizontalScrollBar()->isVisibleTo(this) != validRange)) {
         horizontalScrollBar()->setVisible(validRange);
     }
     // END bugs 213068, 287847 --------------------------------------------------------------
 }
 
 void KCategorizedView::currentChanged(const QModelIndex &current, const QModelIndex &previous)
 {
     QListView::currentChanged(current, previous);
 }
 
 void KCategorizedView::dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight, const QVector<int> &roles)
 {
     QListView::dataChanged(topLeft, bottomRight, roles);
     if (!d->isCategorized()) {
         return;
     }
 
     *d->hoveredBlock = KCategorizedViewPrivate::Block();
     d->hoveredCategory = QString();
 
     // BEGIN: since the model changed data, we need to reconsider item sizes
     int i = topLeft.row();
     int indexToCheck = i;
     QModelIndex categoryIndex;
     QString category;
     KCategorizedViewPrivate::Block *block;
     while (i <= bottomRight.row()) {
         const QModelIndex currIndex = d->proxyModel->index(i, modelColumn(), rootIndex());
         if (i == indexToCheck) {
             categoryIndex = d->proxyModel->index(i, d->proxyModel->sortColumn(), rootIndex());
             category = categoryIndex.data(KCategorizedSortFilterProxyModel::CategoryDisplayRole).toString();
             block = &d->blocks[category];
             block->quarantineStart = currIndex;
             indexToCheck = block->firstIndex.row() + block->items.count();
         }
         visualRect(currIndex);
         ++i;
     }
     // END: since the model changed data, we need to reconsider item sizes
 }
 
 void KCategorizedView::rowsInserted(const QModelIndex &parent, int start, int end)
 {
     QListView::rowsInserted(parent, start, end);
     if (!d->isCategorized()) {
         return;
     }
 
     *d->hoveredBlock = KCategorizedViewPrivate::Block();
     d->hoveredCategory = QString();
     d->rowsInserted(parent, start, end);
 }
 
 #if KITEMVIEWS_BUILD_DEPRECATED_SINCE(4, 4)
 void KCategorizedView::rowsInsertedArtifficial(const QModelIndex &parent, int start, int end)
 {
     Q_UNUSED(parent);
     Q_UNUSED(start);
     Q_UNUSED(end);
 }
 #endif
 
 #if KITEMVIEWS_BUILD_DEPRECATED_SINCE(4, 4)
 void KCategorizedView::rowsRemoved(const QModelIndex &parent, int start, int end)
 {
     Q_UNUSED(parent);
     Q_UNUSED(start);
     Q_UNUSED(end);
 }
 #endif
 
 void KCategorizedView::slotLayoutChanged()
 {
     if (!d->isCategorized()) {
         return;
     }
 
     d->blocks.clear();
     *d->hoveredBlock = KCategorizedViewPrivate::Block();
     d->hoveredCategory = QString();
     if (d->proxyModel->rowCount()) {
         d->rowsInserted(rootIndex(), 0, d->proxyModel->rowCount() - 1);
     }
 }
 
 // END: Public part
 
 #include "moc_kcategorizedview.cpp"