qtreeview.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 "qtreeview.h"
 
#include <qheaderview.h>
#include <qabstractitemdelegate.h>
#include <qapplication.h>
#include <qscrollbar.h>
#include <qpainter.h>
#include <qstack.h>
#include <qstyle.h>
#include <qstyleoption.h>
#include <qevent.h>
#include <qpen.h>
#include <qdebug.h>
#include <QMetaMethod>
#include <private/qscrollbar_p.h>
#if QT_CONFIG(accessibility)
#include <qaccessible.h>
#endif
 
#include <private/qapplication_p.h>
#include <private/qtreeview_p.h>
#include <private/qheaderview_p.h>
 
#include <algorithm>
 
QT_BEGIN_NAMESPACE
 
QTreeView::QTreeView(QWidget *parent)
    : QAbstractItemView(*new QTreeViewPrivate, parent)
{
    Q_D(QTreeView);
    d->initialize();
}
 
QTreeView::QTreeView(QTreeViewPrivate &dd, QWidget *parent)
    : QAbstractItemView(dd, parent)
{
    Q_D(QTreeView);
    d->initialize();
}
 
QTreeView::~QTreeView()
{
    Q_D(QTreeView);
    d->clearConnections();
}
 
void QTreeView::setModel(QAbstractItemModel *model)
{
    Q_D(QTreeView);
    if (model == d->model)
        return;
    if (d->model && d->model != QAbstractItemModelPrivate::staticEmptyModel()) {
        for (const QMetaObject::Connection &connection : d->modelConnections)
            QObject::disconnect(connection);
    }
 
    if (d->selectionModel) { // support row editing
        QObject::disconnect(d->selectionmodelConnection);
    }
    d->viewItems.clear();
    d->expandedIndexes.clear();
    d->hiddenIndexes.clear();
    d->geometryRecursionBlock = true;   // do not update geometries due to signals from the headers
    d->header->setModel(model);
    d->geometryRecursionBlock = false;
    QAbstractItemView::setModel(model);
 
    if (d->model) {
        // QAbstractItemView connects to a private slot
        QObjectPrivate::disconnect(d->model, &QAbstractItemModel::rowsRemoved,
                                   d, &QAbstractItemViewPrivate::rowsRemoved);
        // do header layout after the tree
        QObjectPrivate::disconnect(d->model, &QAbstractItemModel::layoutChanged,
                                   d->header->d_func(), &QAbstractItemViewPrivate::layoutChanged);
 
        d->modelConnections = {
            // QTreeView has a public slot for this
            QObject::connect(d->model, &QAbstractItemModel::rowsRemoved,
                             this, &QTreeView::rowsRemoved),
            QObjectPrivate::connect(d->model, &QAbstractItemModel::modelAboutToBeReset,
                                    d, &QTreeViewPrivate::modelAboutToBeReset)
        };
    }
    if (d->sortingEnabled)
        d->sortIndicatorChanged(header()->sortIndicatorSection(), header()->sortIndicatorOrder());
}
 
void QTreeView::setRootIndex(const QModelIndex &index)
{
    Q_D(QTreeView);
    d->header->setRootIndex(index);
    QAbstractItemView::setRootIndex(index);
}
 
void QTreeView::setSelectionModel(QItemSelectionModel *selectionModel)
{
    Q_D(QTreeView);
    Q_ASSERT(selectionModel);
    if (d->selectionModel) {
        // support row editing
        QObject::disconnect(d->selectionmodelConnection);
    }
 
    d->header->setSelectionModel(selectionModel);
    QAbstractItemView::setSelectionModel(selectionModel);
 
    if (d->selectionModel) {
        // support row editing
        d->selectionmodelConnection =
            connect(d->selectionModel, &QItemSelectionModel::currentRowChanged,
                    d->model, &QAbstractItemModel::submit);
    }
}
 
QHeaderView *QTreeView::header() const
{
    Q_D(const QTreeView);
    return d->header;
}
 
void QTreeView::setHeader(QHeaderView *header)
{
    Q_D(QTreeView);
    if (header == d->header || !header)
        return;
    if (d->header && d->header->parent() == this)
        delete d->header;
    d->header = header;
    d->header->setParent(this);
    d->header->setFirstSectionMovable(false);
 
    if (!d->header->model()) {
        d->header->setModel(d->model);
        if (d->selectionModel)
            d->header->setSelectionModel(d->selectionModel);
    }
 
    d->headerConnections = {
        connect(d->header, &QHeaderView::sectionResized,
                this, &QTreeView::columnResized),
        connect(d->header, &QHeaderView::sectionMoved,
                this, &QTreeView::columnMoved),
        connect(d->header, &QHeaderView::sectionCountChanged,
                this, &QTreeView::columnCountChanged),
        connect(d->header, &QHeaderView::sectionHandleDoubleClicked,
                this, &QTreeView::resizeColumnToContents),
        connect(d->header, &QHeaderView::geometriesChanged,
                this, &QTreeView::updateGeometries)
    };
 
    setSortingEnabled(d->sortingEnabled);
    d->updateGeometry();
}
 
int QTreeView::autoExpandDelay() const
{
    Q_D(const QTreeView);
    return d->autoExpandDelay;
}
 
void QTreeView::setAutoExpandDelay(int delay)
{
    Q_D(QTreeView);
    d->autoExpandDelay = delay;
}
 
int QTreeView::indentation() const
{
    Q_D(const QTreeView);
    return d->indent;
}
 
void QTreeView::setIndentation(int i)
{
    Q_D(QTreeView);
    if (!d->customIndent || (i != d->indent)) {
        d->indent = i;
        d->customIndent = true;
        d->viewport->update();
    }
}
 
void QTreeView::resetIndentation()
{
    Q_D(QTreeView);
    if (d->customIndent) {
        d->updateIndentationFromStyle();
        d->customIndent = false;
    }
}
 
bool QTreeView::rootIsDecorated() const
{
    Q_D(const QTreeView);
    return d->rootDecoration;
}
 
void QTreeView::setRootIsDecorated(bool show)
{
    Q_D(QTreeView);
    if (show != d->rootDecoration) {
        d->rootDecoration = show;
        d->viewport->update();
    }
}
 
bool QTreeView::uniformRowHeights() const
{
    Q_D(const QTreeView);
    return d->uniformRowHeights;
}
 
void QTreeView::setUniformRowHeights(bool uniform)
{
    Q_D(QTreeView);
    d->uniformRowHeights = uniform;
}
 
bool QTreeView::itemsExpandable() const
{
    Q_D(const QTreeView);
    return d->itemsExpandable;
}
 
void QTreeView::setItemsExpandable(bool enable)
{
    Q_D(QTreeView);
    d->itemsExpandable = enable;
}
 
bool QTreeView::expandsOnDoubleClick() const
{
    Q_D(const QTreeView);
    return d->expandsOnDoubleClick;
}
 
void QTreeView::setExpandsOnDoubleClick(bool enable)
{
    Q_D(QTreeView);
    d->expandsOnDoubleClick = enable;
}
 
int QTreeView::columnViewportPosition(int column) const
{
    Q_D(const QTreeView);
    return d->header->sectionViewportPosition(column);
}
 
int QTreeView::columnWidth(int column) const
{
    Q_D(const QTreeView);
    return d->header->sectionSize(column);
}
 
void QTreeView::setColumnWidth(int column, int width)
{
    Q_D(QTreeView);
    d->header->resizeSection(column, width);
}
 
int QTreeView::columnAt(int x) const
{
    Q_D(const QTreeView);
    return d->header->logicalIndexAt(x);
}
 
bool QTreeView::isColumnHidden(int column) const
{
    Q_D(const QTreeView);
    return d->header->isSectionHidden(column);
}
 
void QTreeView::setColumnHidden(int column, bool hide)
{
    Q_D(QTreeView);
    if (column < 0 || column >= d->header->count())
        return;
    d->header->setSectionHidden(column, hide);
}
 
bool QTreeView::isHeaderHidden() const
{
    Q_D(const QTreeView);
    return d->header->isHidden();
}
 
void QTreeView::setHeaderHidden(bool hide)
{
    Q_D(QTreeView);
    d->header->setHidden(hide);
}
 
bool QTreeView::isRowHidden(int row, const QModelIndex &parent) const
{
    Q_D(const QTreeView);
    if (!d->model)
        return false;
    return d->isRowHidden(d->model->index(row, 0, parent));
}
 
void QTreeView::setRowHidden(int row, const QModelIndex &parent, bool hide)
{
    Q_D(QTreeView);
    if (!d->model)
        return;
    QModelIndex index = d->model->index(row, 0, parent);
    if (!index.isValid())
        return;
 
    if (hide) {
        d->hiddenIndexes.insert(index);
    } else if (d->isPersistent(index)) { //if the index is not persistent, it cannot be in the set
        d->hiddenIndexes.remove(index);
    }
 
    d->doDelayedItemsLayout();
}
 
bool QTreeView::isFirstColumnSpanned(int row, const QModelIndex &parent) const
{
    Q_D(const QTreeView);
    if (d->spanningIndexes.isEmpty() || !d->model)
        return false;
    const QModelIndex index = d->model->index(row, 0, parent);
    return d->spanningIndexes.contains(index);
}
 
void QTreeView::setFirstColumnSpanned(int row, const QModelIndex &parent, bool span)
{
    Q_D(QTreeView);
    if (!d->model)
        return;
    const QModelIndex index = d->model->index(row, 0, parent);
    if (!index.isValid())
        return;
 
    if (span)
        d->spanningIndexes.insert(index);
    else
        d->spanningIndexes.remove(index);
 
    d->executePostedLayout();
    int i = d->viewIndex(index);
    if (i >= 0)
        d->viewItems[i].spanning = span;
 
    d->viewport->update();
}
 
void QTreeView::dataChanged(const QModelIndex &topLeft, const QModelIndex &bottomRight,
                            const QList<int> &roles)
{
    Q_D(QTreeView);
 
    // if we are going to do a complete relayout anyway, there is no need to update
    if (d->delayedPendingLayout)
        return;
 
    // refresh the height cache here; we don't really lose anything by getting the size hint,
    // since QAbstractItemView::dataChanged() will get the visualRect for the items anyway
 
    bool sizeChanged = false;
    int topViewIndex = d->viewIndex(topLeft);
    if (topViewIndex == 0) {
        int newDefaultItemHeight = indexRowSizeHint(topLeft);
        sizeChanged = d->defaultItemHeight != newDefaultItemHeight;
        d->defaultItemHeight = newDefaultItemHeight;
    }
 
    if (topViewIndex != -1) {
        if (topLeft.row() == bottomRight.row()) {
            int oldHeight = d->itemHeight(topViewIndex);
            d->invalidateHeightCache(topViewIndex);
            sizeChanged |= (oldHeight != d->itemHeight(topViewIndex));
            if (topLeft.column() == 0)
                d->viewItems[topViewIndex].hasChildren = d->hasVisibleChildren(topLeft);
        } else {
            int bottomViewIndex = d->viewIndex(bottomRight);
            for (int i = topViewIndex; i <= bottomViewIndex; ++i) {
                int oldHeight = d->itemHeight(i);
                d->invalidateHeightCache(i);
                sizeChanged |= (oldHeight != d->itemHeight(i));
                if (topLeft.column() == 0)
                    d->viewItems[i].hasChildren = d->hasVisibleChildren(d->viewItems.at(i).index);
            }
        }
    }
 
    if (sizeChanged) {
        d->updateScrollBars();
        d->viewport->update();
    }
    QAbstractItemView::dataChanged(topLeft, bottomRight, roles);
}
 
void QTreeView::hideColumn(int column)
{
    Q_D(QTreeView);
    if (d->header->isSectionHidden(column))
        return;
    d->header->hideSection(column);
    doItemsLayout();
}
 
void QTreeView::showColumn(int column)
{
    Q_D(QTreeView);
    if (!d->header->isSectionHidden(column))
        return;
    d->header->showSection(column);
    doItemsLayout();
}
 
void QTreeView::expand(const QModelIndex &index)
{
    Q_D(QTreeView);
    if (!d->isIndexValid(index))
        return;
    if (index.flags() & Qt::ItemNeverHasChildren)
        return;
    if (d->isIndexExpanded(index))
        return;
    if (d->delayedPendingLayout) {
        //A complete relayout is going to be performed, just store the expanded index, no need to layout.
        if (d->storeExpanded(index))
            emit expanded(index);
        return;
    }
 
    int i = d->viewIndex(index);
    if (i != -1) { // is visible
        d->expand(i, true);
        if (!d->isAnimating()) {
            updateGeometries();
            d->viewport->update();
        }
    } else if (d->storeExpanded(index)) {
        emit expanded(index);
    }
}
 
void QTreeView::collapse(const QModelIndex &index)
{
    Q_D(QTreeView);
    if (!d->isIndexValid(index))
        return;
    if (!d->isIndexExpanded(index))
        return;
    //if the current item is now invisible, the autoscroll will expand the tree to see it, so disable the autoscroll
    d->delayedAutoScroll.stop();
 
    if (d->delayedPendingLayout) {
        //A complete relayout is going to be performed, just un-store the expanded index, no need to layout.
        if (d->isPersistent(index) && d->expandedIndexes.remove(index))
            emit collapsed(index);
        return;
    }
    int i = d->viewIndex(index);
    if (i != -1) { // is visible
        d->collapse(i, true);
        if (!d->isAnimating()) {
            updateGeometries();
            viewport()->update();
        }
    } else {
        if (d->isPersistent(index) && d->expandedIndexes.remove(index))
            emit collapsed(index);
    }
}
 
bool QTreeView::isExpanded(const QModelIndex &index) const
{
    Q_D(const QTreeView);
    return d->isIndexExpanded(index);
}
 
void QTreeView::setExpanded(const QModelIndex &index, bool expanded)
{
    if (expanded)
        this->expand(index);
    else
        this->collapse(index);
}
 
void QTreeView::setSortingEnabled(bool enable)
{
    Q_D(QTreeView);
    header()->setSortIndicatorShown(enable);
    header()->setSectionsClickable(enable);
    if (enable) {
        //sortByColumn has to be called before we connect or set the sortingEnabled flag
        // because otherwise it will not call sort on the model.
        sortByColumn(header()->sortIndicatorSection(), header()->sortIndicatorOrder());
        d->sortHeaderConnection =
            QObjectPrivate::connect(header(), &QHeaderView::sortIndicatorChanged,
                                    d, &QTreeViewPrivate::sortIndicatorChanged,
                                    Qt::UniqueConnection);
    } else {
        QObject::disconnect(d->sortHeaderConnection);
    }
    d->sortingEnabled = enable;
}
 
bool QTreeView::isSortingEnabled() const
{
    Q_D(const QTreeView);
    return d->sortingEnabled;
}
 
void QTreeView::setAnimated(bool animate)
{
    Q_D(QTreeView);
    d->animationsEnabled = animate;
}
 
bool QTreeView::isAnimated() const
{
    Q_D(const QTreeView);
    return d->animationsEnabled;
}
 
void QTreeView::setAllColumnsShowFocus(bool enable)
{
    Q_D(QTreeView);
    if (d->allColumnsShowFocus == enable)
        return;
    d->allColumnsShowFocus = enable;
    d->viewport->update();
}
 
bool QTreeView::allColumnsShowFocus() const
{
    Q_D(const QTreeView);
    return d->allColumnsShowFocus;
}
 
void QTreeView::setWordWrap(bool on)
{
    Q_D(QTreeView);
    if (d->wrapItemText == on)
        return;
    d->wrapItemText = on;
    d->doDelayedItemsLayout();
}
 
bool QTreeView::wordWrap() const
{
    Q_D(const QTreeView);
    return d->wrapItemText;
}
 
void QTreeView::setTreePosition(int index)
{
    Q_D(QTreeView);
    d->treePosition = index;
    d->viewport->update();
}
 
int QTreeView::treePosition() const
{
    Q_D(const QTreeView);
    return d->treePosition;
}
 
void QTreeView::keyboardSearch(const QString &search)
{
    Q_D(QTreeView);
    if (!d->model->rowCount(d->root) || !d->model->columnCount(d->root))
        return;
 
    // Do a relayout nows, so that we can utilize viewItems
    d->executePostedLayout();
    if (d->viewItems.isEmpty())
        return;
 
    QModelIndex start;
    if (currentIndex().isValid())
        start = currentIndex();
    else
        start = d->viewItems.at(0).index;
 
    bool skipRow = false;
    bool keyboardTimeWasValid = d->keyboardInputTime.isValid();
    qint64 keyboardInputTimeElapsed;
    if (keyboardTimeWasValid)
        keyboardInputTimeElapsed = d->keyboardInputTime.restart();
    else
        d->keyboardInputTime.start();
    if (search.isEmpty() || !keyboardTimeWasValid
        || keyboardInputTimeElapsed > QApplication::keyboardInputInterval()) {
        d->keyboardInput = search;
        skipRow = currentIndex().isValid(); //if it is not valid we should really start at QModelIndex(0,0)
    } else {
        d->keyboardInput += search;
    }
 
    // special case for searches with same key like 'aaaaa'
    bool sameKey = false;
    if (d->keyboardInput.size() > 1) {
        int c = d->keyboardInput.count(d->keyboardInput.at(d->keyboardInput.size() - 1));
        sameKey = (c == d->keyboardInput.size());
        if (sameKey)
            skipRow = true;
    }
 
    // skip if we are searching for the same key or a new search started
    if (skipRow) {
        if (indexBelow(start).isValid()) {
            start = indexBelow(start);
        } else {
            const int origCol = start.column();
            start = d->viewItems.at(0).index;
            if (origCol != start.column())
                start = start.sibling(start.row(), origCol);
        }
    }
 
    int startIndex = d->viewIndex(start);
    if (startIndex <= -1)
        return;
 
    int previousLevel = -1;
    int bestAbove = -1;
    int bestBelow = -1;
    QString searchString = sameKey ? QString(d->keyboardInput.at(0)) : d->keyboardInput;
    for (int i = 0; i < d->viewItems.size(); ++i) {
        if ((int)d->viewItems.at(i).level > previousLevel) {
            QModelIndex searchFrom = d->viewItems.at(i).index;
            if (start.column() > 0)
                searchFrom = searchFrom.sibling(searchFrom.row(), start.column());
            if (searchFrom.parent() == start.parent())
                searchFrom = start;
            QModelIndexList match = d->model->match(searchFrom, Qt::DisplayRole, searchString);
            if (match.size()) {
                int hitIndex = d->viewIndex(match.at(0));
                if (hitIndex >= 0 && hitIndex < startIndex)
                    bestAbove = bestAbove == -1 ? hitIndex : qMin(hitIndex, bestAbove);
                else if (hitIndex >= startIndex)
                    bestBelow = bestBelow == -1 ? hitIndex : qMin(hitIndex, bestBelow);
            }
        }
        previousLevel = d->viewItems.at(i).level;
    }
 
    QModelIndex index;
    if (bestBelow > -1)
        index = d->viewItems.at(bestBelow).index;
    else if (bestAbove > -1)
        index = d->viewItems.at(bestAbove).index;
 
    if (start.column() > 0)
        index = index.sibling(index.row(), start.column());
 
    if (index.isValid())
        setCurrentIndex(index);
}
 
QRect QTreeView::visualRect(const QModelIndex &index) const
{
    Q_D(const QTreeView);
    return d->visualRect(index, QTreeViewPrivate::SingleSection);
}
 
QRect QTreeViewPrivate::visualRect(const QModelIndex &index, RectRule rule) const
{
    Q_Q(const QTreeView);
 
    if (!isIndexValid(index))
        return QRect();
 
    // Calculate the entire row's rectangle, even if one of the elements is hidden
    if (q->isIndexHidden(index) && rule != FullRow)
        return QRect();
 
    executePostedLayout();
 
    const int viewIndex = this->viewIndex(index);
    if (viewIndex < 0)
        return QRect();
 
    const bool spanning = viewItems.at(viewIndex).spanning;
    const int column = index.column();
 
    // if we have a spanning item, make the selection stretch from left to right
    int x = (spanning ? 0 : q->columnViewportPosition(column));
    int width = (spanning ? header->length() : q->columnWidth(column));
 
    const bool addIndentation = isTreePosition(column) && (column > 0 || rule == SingleSection);
 
    if (rule == FullRow) {
        x = 0;
        width = q->viewport()->width();
    } else if (addIndentation) {
        // calculate indentation
        const int indentation = indentationForItem(viewIndex);
        width -= indentation;
        if (!q->isRightToLeft())
            x += indentation;
    }
 
    const int y = coordinateForItem(viewIndex);
    const int height = itemHeight(viewIndex);
 
    return QRect(x, y, width, height);
}
 
void QTreeView::scrollTo(const QModelIndex &index, ScrollHint hint)
{
    Q_D(QTreeView);
 
    if (!d->isIndexValid(index))
        return;
 
    d->executePostedLayout();
    d->updateScrollBars();
 
    // Expand all parents if the parent(s) of the node are not expanded.
    QModelIndex parent = index.parent();
    while (parent != d->root && parent.isValid() && state() == NoState && d->itemsExpandable) {
        if (!isExpanded(parent))
            expand(parent);
        parent = d->model->parent(parent);
    }
 
    int item = d->viewIndex(index);
    if (item < 0)
        return;
 
    QRect area = d->viewport->rect();
 
    // vertical
    if (verticalScrollMode() == QAbstractItemView::ScrollPerItem) {
        int top = verticalScrollBar()->value();
        int bottom = top + verticalScrollBar()->pageStep();
        if (hint == EnsureVisible && item >= top && item < bottom) {
            // nothing to do
        } else if (hint == PositionAtTop || (hint == EnsureVisible && item < top)) {
            verticalScrollBar()->setValue(item);
        } else { // PositionAtBottom or PositionAtCenter
            const int currentItemHeight = d->itemHeight(item);
            int y = (hint == PositionAtCenter
                 //we center on the current item with a preference to the top item (ie. -1)
                     ? area.height() / 2 + currentItemHeight - 1
                 //otherwise we simply take the whole space
                     : area.height());
            if (y > currentItemHeight) {
                while (item >= 0) {
                    y -= d->itemHeight(item);
                    if (y < 0) { //there is no more space left
                        item++;
                        break;
                    }
                    item--;
                }
            }
            verticalScrollBar()->setValue(item);
        }
    } else { // ScrollPerPixel
        QRect rect(columnViewportPosition(index.column()),
                   d->coordinateForItem(item), // ### slow for items outside the view
                   columnWidth(index.column()),
                   d->itemHeight(item));
 
        if (rect.isEmpty()) {
            // nothing to do
        } else if (hint == EnsureVisible && area.contains(rect)) {
            d->viewport->update(rect);
            // nothing to do
        } else {
            bool above = (hint == EnsureVisible
                        && (rect.top() < area.top()
                            || area.height() < rect.height()));
            bool below = (hint == EnsureVisible
                        && rect.bottom() > area.bottom()
                        && rect.height() < area.height());
 
            int verticalValue = verticalScrollBar()->value();
            if (hint == PositionAtTop || above)
                verticalValue += rect.top();
            else if (hint == PositionAtBottom || below)
                verticalValue += rect.bottom() - area.height();
            else if (hint == PositionAtCenter)
                verticalValue += rect.top() - ((area.height() - rect.height()) / 2);
            verticalScrollBar()->setValue(verticalValue);
        }
    }
    // horizontal
    int viewportWidth = d->viewport->width();
    int horizontalOffset = d->header->offset();
    int horizontalPosition = d->header->sectionPosition(index.column());
    int cellWidth = d->header->sectionSize(index.column());
 
    if (hint == PositionAtCenter) {
        horizontalScrollBar()->setValue(horizontalPosition - ((viewportWidth - cellWidth) / 2));
    } else {
        if (horizontalPosition - horizontalOffset < 0 || cellWidth > viewportWidth)
            horizontalScrollBar()->setValue(horizontalPosition);
        else if (horizontalPosition - horizontalOffset + cellWidth > viewportWidth)
            horizontalScrollBar()->setValue(horizontalPosition - viewportWidth + cellWidth);
    }
}
 
void QTreeView::changeEvent(QEvent *event)
{
    Q_D(QTreeView);
    if (event->type() == QEvent::StyleChange) {
        if (!d->customIndent) {
            // QAbstractItemView calls this method in case of a style change,
            // so update the indentation here if it wasn't set manually.
            d->updateIndentationFromStyle();
        }
    }
    QAbstractItemView::changeEvent(event);
}
 
void QTreeView::timerEvent(QTimerEvent *event)
{
    Q_D(QTreeView);
    if (event->timerId() == d->columnResizeTimerID) {
        updateGeometries();
        killTimer(d->columnResizeTimerID);
        d->columnResizeTimerID = 0;
        QRect rect;
        int viewportHeight = d->viewport->height();
        int viewportWidth = d->viewport->width();
        for (int i = d->columnsToUpdate.size() - 1; i >= 0; --i) {
            int column = d->columnsToUpdate.at(i);
            int x = columnViewportPosition(column);
            if (isRightToLeft())
                rect |= QRect(0, 0, x + columnWidth(column), viewportHeight);
            else
                rect |= QRect(x, 0, viewportWidth - x, viewportHeight);
        }
        d->viewport->update(rect.normalized());
        d->columnsToUpdate.clear();
    } else if (event->timerId() == d->openTimer.timerId()) {
        QPoint pos = d->viewport->mapFromGlobal(QCursor::pos());
        if (state() == QAbstractItemView::DraggingState
            && d->viewport->rect().contains(pos)) {
            QModelIndex index = indexAt(pos);
            setExpanded(index, !isExpanded(index));
        }
        d->openTimer.stop();
    }
 
    QAbstractItemView::timerEvent(event);
}
 
#if QT_CONFIG(draganddrop)
void QTreeView::dragMoveEvent(QDragMoveEvent *event)
{
    Q_D(QTreeView);
    if (d->autoExpandDelay >= 0)
        d->openTimer.start(d->autoExpandDelay, this);
    QAbstractItemView::dragMoveEvent(event);
}
#endif
 
bool QTreeView::viewportEvent(QEvent *event)
{
    Q_D(QTreeView);
    switch (event->type()) {
    case QEvent::HoverEnter:
    case QEvent::HoverLeave:
    case QEvent::HoverMove: {
        QHoverEvent *he = static_cast<QHoverEvent*>(event);
        const int oldBranch = d->hoverBranch;
        d->hoverBranch = d->itemDecorationAt(he->position().toPoint());
        QModelIndex newIndex = indexAt(he->position().toPoint());
        if (d->hover != newIndex || d->hoverBranch != oldBranch) {
            // Update the whole hovered over row. No need to update the old hovered
            // row, that is taken care in superclass hover handling.
            viewport()->update(d->visualRect(newIndex, QTreeViewPrivate::FullRow));
        }
        break; }
    default:
        break;
    }
    return QAbstractItemView::viewportEvent(event);
}
 
void QTreeView::paintEvent(QPaintEvent *event)
{
    Q_D(QTreeView);
    d->executePostedLayout();
    QPainter painter(viewport());
#if QT_CONFIG(animation)
    if (d->isAnimating()) {
        drawTree(&painter, event->region() - d->animatedOperation.rect());
        d->drawAnimatedOperation(&painter);
    } else
#endif // animation
    {
        drawTree(&painter, event->region());
#if QT_CONFIG(draganddrop)
        d->paintDropIndicator(&painter);
#endif
    }
}
 
int QTreeViewPrivate::logicalIndexForTree() const
{
    int index = treePosition;
    if (index < 0)
        index = header->logicalIndex(0);
    return index;
}
 
void QTreeViewPrivate::paintAlternatingRowColors(QPainter *painter, QStyleOptionViewItem *option, int y, int bottom) const
{
    Q_Q(const QTreeView);
    if (!alternatingColors || !q->style()->styleHint(QStyle::SH_ItemView_PaintAlternatingRowColorsForEmptyArea, option, q))
        return;
    int rowHeight = defaultItemHeight;
    if (rowHeight <= 0) {
        rowHeight = itemDelegate->sizeHint(*option, QModelIndex()).height();
        if (rowHeight <= 0)
            return;
    }
    while (y <= bottom) {
        option->rect.setRect(0, y, viewport->width(), rowHeight);
        option->features.setFlag(QStyleOptionViewItem::Alternate, current & 1);
        ++current;
        q->style()->drawPrimitive(QStyle::PE_PanelItemViewRow, option, painter, q);
        y += rowHeight;
    }
}
 
bool QTreeViewPrivate::expandOrCollapseItemAtPos(const QPoint &pos)
{
    Q_Q(QTreeView);
    // we want to handle mousePress in EditingState (persistent editors)
    if ((state != QAbstractItemView::NoState
                && state != QAbstractItemView::EditingState)
                || !viewport->rect().contains(pos))
        return true;
 
    int i = itemDecorationAt(pos);
    if ((i != -1) && itemsExpandable && hasVisibleChildren(viewItems.at(i).index)) {
        if (viewItems.at(i).expanded)
            collapse(i, true);
        else
            expand(i, true);
        if (!isAnimating()) {
            q->updateGeometries();
            viewport->update();
        }
        return true;
    }
    return false;
}
 
void QTreeViewPrivate::modelDestroyed()
{
    //we need to clear the viewItems because it contains QModelIndexes to
    //the model currently being destroyed
    viewItems.clear();
    QAbstractItemViewPrivate::modelDestroyed();
}
 
QRect QTreeViewPrivate::intersectedRect(const QRect rect, const QModelIndex &topLeft, const QModelIndex &bottomRight) const
{
    const auto parentIdx = topLeft.parent();
    executePostedLayout();
    QRect updateRect;
    for (int r = topLeft.row(); r <= bottomRight.row(); ++r) {
        if (isRowHidden(model->index(r, 0, parentIdx)))
            continue;
        for (int c = topLeft.column(); c <= bottomRight.column(); ++c) {
            const QModelIndex idx(model->index(r, c, parentIdx));
            updateRect |= visualRect(idx, SingleSection);
        }
    }
    return rect.intersected(updateRect);
}
 
QItemViewPaintPairs QTreeViewPrivate::draggablePaintPairs(const QModelIndexList &indexes, QRect *r) const
{
    Q_ASSERT(r);
    Q_Q(const QTreeView);
    if (spanningIndexes.isEmpty())
        return QAbstractItemViewPrivate::draggablePaintPairs(indexes, r);
    QModelIndexList list;
    for (const QModelIndex &idx : indexes) {
        if (idx.column() > 0 && q->isFirstColumnSpanned(idx.row(), idx.parent()))
            continue;
        list << idx;
    }
    return QAbstractItemViewPrivate::draggablePaintPairs(list, r);
}
 
void QTreeViewPrivate::adjustViewOptionsForIndex(QStyleOptionViewItem *option, const QModelIndex &current) const
{
    const int row = viewIndex(current); // get the index in viewItems[]
    option->state = option->state | (viewItems.at(row).expanded ? QStyle::State_Open : QStyle::State_None)
                                  | (viewItems.at(row).hasChildren ? QStyle::State_Children : QStyle::State_None)
                                  | (viewItems.at(row).hasMoreSiblings ? QStyle::State_Sibling : QStyle::State_None);
 
    option->showDecorationSelected = (selectionBehavior & QTreeView::SelectRows)
                                     || option->showDecorationSelected;
 
    QList<int>
            logicalIndices; // index = visual index of visible columns only. data = logical index.
    QList<QStyleOptionViewItem::ViewItemPosition>
            viewItemPosList; // vector of left/middle/end for each logicalIndex, visible columns
                             // only.
    const bool spanning = viewItems.at(row).spanning;
    const int left = (spanning ? header->visualIndex(0) : 0);
    const int right = (spanning ? header->visualIndex(0) : header->count() - 1 );
    calcLogicalIndices(&logicalIndices, &viewItemPosList, left, right);
 
    const int visualIndex = logicalIndices.indexOf(current.column());
    option->viewItemPosition = viewItemPosList.at(visualIndex);
}
 
 
void QTreeView::drawTree(QPainter *painter, const QRegion &region) const
{
    Q_D(const QTreeView);
    // d->viewItems changes when posted layouts are executed in itemDecorationAt, so don't copy
    const QList<QTreeViewItem> &viewItems = d->viewItems;
 
    QStyleOptionViewItem option;
    initViewItemOption(&option);
    const QStyle::State state = option.state;
    d->current = 0;
 
    if (viewItems.size() == 0 || d->header->count() == 0 || !d->itemDelegate) {
        d->paintAlternatingRowColors(painter, &option, 0, region.boundingRect().bottom()+1);
        return;
    }
 
    int firstVisibleItemOffset = 0;
    const int firstVisibleItem = d->firstVisibleItem(&firstVisibleItemOffset);
    if (firstVisibleItem < 0) {
        d->paintAlternatingRowColors(painter, &option, 0, region.boundingRect().bottom()+1);
        return;
    }
 
    const int viewportWidth = d->viewport->width();
 
    QPoint hoverPos = d->viewport->mapFromGlobal(QCursor::pos());
    d->hoverBranch = d->itemDecorationAt(hoverPos);
 
    QList<int> drawn;
    bool multipleRects = (region.rectCount() > 1);
    for (const QRect &a : region) {
        const QRect area = (multipleRects
                            ? QRect(0, a.y(), viewportWidth, a.height())
                            : a);
        d->leftAndRight = d->startAndEndColumns(area);
 
        int i = firstVisibleItem; // the first item at the top of the viewport
        int y = firstVisibleItemOffset; // we may only see part of the first item
 
        // start at the top of the viewport  and iterate down to the update area
        for (; i < viewItems.size(); ++i) {
            const int itemHeight = d->itemHeight(i);
            if (y + itemHeight > area.top())
                break;
            y += itemHeight;
        }
 
        // paint the visible rows
        for (; i < viewItems.size() && y <= area.bottom(); ++i) {
            const QModelIndex &index = viewItems.at(i).index;
            const int itemHeight = d->itemHeight(i);
            option.rect = d->visualRect(index, QTreeViewPrivate::FullRow);
            option.state = state | (viewItems.at(i).expanded ? QStyle::State_Open : QStyle::State_None)
                                 | (viewItems.at(i).hasChildren ? QStyle::State_Children : QStyle::State_None)
                                 | (viewItems.at(i).hasMoreSiblings ? QStyle::State_Sibling : QStyle::State_None);
            d->current = i;
            d->spanning = viewItems.at(i).spanning;
            if (!multipleRects || !drawn.contains(i)) {
                drawRow(painter, option, viewItems.at(i).index);
                if (multipleRects)   // even if the rect only intersects the item,
                    drawn.append(i); // the entire item will be painted
            }
            y += itemHeight;
        }
 
        if (y <= area.bottom()) {
            d->current = i;
            d->paintAlternatingRowColors(painter, &option, y, area.bottom());
        }
    }
}
 
static inline bool ancestorOf(QObject *widget, QObject *other)
{
    for (QObject *parent = other; parent != nullptr; parent = parent->parent()) {
        if (parent == widget)
            return true;
    }
    return false;
}
 
void QTreeViewPrivate::calcLogicalIndices(
        QList<int> *logicalIndices, QList<QStyleOptionViewItem::ViewItemPosition> *itemPositions,
        int left, int right) const
{
    const int columnCount = header->count();
    /* 'left' and 'right' are the left-most and right-most visible visual indices.
       Compute the first visible logical indices before and after the left and right.
       We will use these values to determine the QStyleOptionViewItem::viewItemPosition. */
    int logicalIndexBeforeLeft = -1, logicalIndexAfterRight = -1;
    for (int visualIndex = left - 1; visualIndex >= 0; --visualIndex) {
        int logicalIndex = header->logicalIndex(visualIndex);
        if (!header->isSectionHidden(logicalIndex)) {
            logicalIndexBeforeLeft = logicalIndex;
            break;
        }
    }
 
    for (int visualIndex = left; visualIndex < columnCount; ++visualIndex) {
        int logicalIndex = header->logicalIndex(visualIndex);
        if (!header->isSectionHidden(logicalIndex)) {
            if (visualIndex > right) {
                logicalIndexAfterRight = logicalIndex;
                break;
            }
            logicalIndices->append(logicalIndex);
        }
    }
 
    itemPositions->resize(logicalIndices->size());
    for (int currentLogicalSection = 0; currentLogicalSection < logicalIndices->size(); ++currentLogicalSection) {
        const int headerSection = logicalIndices->at(currentLogicalSection);
        // determine the viewItemPosition depending on the position of column 0
        int nextLogicalSection = currentLogicalSection + 1 >= logicalIndices->size()
                                 ? logicalIndexAfterRight
                                 : logicalIndices->at(currentLogicalSection + 1);
        int prevLogicalSection = currentLogicalSection - 1 < 0
                                 ? logicalIndexBeforeLeft
                                 : logicalIndices->at(currentLogicalSection - 1);
        QStyleOptionViewItem::ViewItemPosition pos;
        if (columnCount == 1 || (nextLogicalSection == 0 && prevLogicalSection == -1)
            || (headerSection == 0 && nextLogicalSection == -1) || spanning)
            pos = QStyleOptionViewItem::OnlyOne;
        else if (isTreePosition(headerSection) || (nextLogicalSection != 0 && prevLogicalSection == -1))
            pos = QStyleOptionViewItem::Beginning;
        else if (nextLogicalSection == 0 || nextLogicalSection == -1)
            pos = QStyleOptionViewItem::End;
        else
            pos = QStyleOptionViewItem::Middle;
        (*itemPositions)[currentLogicalSection] = pos;
    }
}
 
int QTreeViewPrivate::widthHintForIndex(const QModelIndex &index, int hint, const QStyleOptionViewItem &option, int i) const
{
    Q_Q(const QTreeView);
    QWidget *editor = editorForIndex(index).widget.data();
    if (editor && persistent.contains(editor)) {
        hint = qMax(hint, editor->sizeHint().width());
        int min = editor->minimumSize().width();
        int max = editor->maximumSize().width();
        hint = qBound(min, hint, max);
    }
    int xhint = q->itemDelegateForIndex(index)->sizeHint(option, index).width();
    hint = qMax(hint, xhint + (isTreePosition(index.column()) ? indentationForItem(i) : 0));
    return hint;
}
 
void QTreeView::drawRow(QPainter *painter, const QStyleOptionViewItem &option,
                        const QModelIndex &index) const
{
    Q_D(const QTreeView);
    QStyleOptionViewItem opt = option;
    const QPoint offset = d->scrollDelayOffset;
    const int y = option.rect.y() + offset.y();
    const QModelIndex parent = index.parent();
    const QHeaderView *header = d->header;
    const QModelIndex current = currentIndex();
    const QModelIndex hover = d->hover;
    const bool reverse = isRightToLeft();
    const QStyle::State state = opt.state;
    const bool spanning = d->spanning;
    const int left = (spanning ? header->visualIndex(0) : d->leftAndRight.first);
    const int right = (spanning ? header->visualIndex(0) : d->leftAndRight.second);
    const bool alternate = d->alternatingColors;
    const bool enabled = (state & QStyle::State_Enabled) != 0;
    const bool allColumnsShowFocus = d->allColumnsShowFocus;
 
 
    // when the row contains an index widget which has focus,
    // we want to paint the entire row as active
    bool indexWidgetHasFocus = false;
    if ((current.row() == index.row()) && !d->editorIndexHash.isEmpty()) {
        const int r = index.row();
        QWidget *fw = QApplication::focusWidget();
        for (int c = 0; c < header->count(); ++c) {
            QModelIndex idx = d->model->index(r, c, parent);
            if (QWidget *editor = indexWidget(idx)) {
                if (ancestorOf(editor, fw)) {
                    indexWidgetHasFocus = true;
                    break;
                }
            }
        }
    }
 
    const bool widgetHasFocus = hasFocus();
    bool currentRowHasFocus = false;
    if (allColumnsShowFocus && widgetHasFocus && current.isValid()) {
        // check if the focus index is before or after the visible columns
        const int r = index.row();
        for (int c = 0; c < left && !currentRowHasFocus; ++c) {
            QModelIndex idx = d->model->index(r, c, parent);
            currentRowHasFocus = (idx == current);
        }
        QModelIndex parent = d->model->parent(index);
        for (int c = right; c < header->count() && !currentRowHasFocus; ++c) {
            currentRowHasFocus = (d->model->index(r, c, parent) == current);
        }
    }
 
    // ### special case: if we select entire rows, then we need to draw the
    // selection in the first column all the way to the second column, rather
    // than just around the item text. We abuse showDecorationSelected to
    // indicate this to the style. Below we will reset this value temporarily
    // to only respect the styleHint while we are rendering the decoration.
    opt.showDecorationSelected = (d->selectionBehavior & SelectRows)
                                 || option.showDecorationSelected;
 
    int width, height = option.rect.height();
    int position;
    QModelIndex modelIndex;
    const bool hoverRow = selectionBehavior() == QAbstractItemView::SelectRows
                  && index.parent() == hover.parent()
                  && index.row() == hover.row();
 
    QList<int> logicalIndices;
    QList<QStyleOptionViewItem::ViewItemPosition>
            viewItemPosList; // vector of left/middle/end for each logicalIndex
    d->calcLogicalIndices(&logicalIndices, &viewItemPosList, left, right);
 
    for (int currentLogicalSection = 0; currentLogicalSection < logicalIndices.size(); ++currentLogicalSection) {
        int headerSection = logicalIndices.at(currentLogicalSection);
        position = columnViewportPosition(headerSection) + offset.x();
        width = header->sectionSize(headerSection);
 
        if (spanning) {
            int lastSection = header->logicalIndex(header->count() - 1);
            if (!reverse) {
                width = columnViewportPosition(lastSection) + header->sectionSize(lastSection) - position;
            } else {
                width += position - columnViewportPosition(lastSection);
                position = columnViewportPosition(lastSection);
            }
        }
 
        modelIndex = d->model->index(index.row(), headerSection, parent);
        if (!modelIndex.isValid())
            continue;
        opt.state = state;
 
        opt.viewItemPosition = viewItemPosList.at(currentLogicalSection);
 
        // fake activeness when row editor has focus
        if (indexWidgetHasFocus)
            opt.state |= QStyle::State_Active;
 
        if (d->selectionModel->isSelected(modelIndex))
            opt.state |= QStyle::State_Selected;
        if (widgetHasFocus && (current == modelIndex)) {
            if (allColumnsShowFocus)
                currentRowHasFocus = true;
            else
                opt.state |= QStyle::State_HasFocus;
        }
        opt.state.setFlag(QStyle::State_MouseOver,
                          (hoverRow || modelIndex == hover)
                          && (option.showDecorationSelected || d->hoverBranch == -1));
 
        if (enabled) {
            QPalette::ColorGroup cg;
            if ((d->model->flags(modelIndex) & Qt::ItemIsEnabled) == 0) {
                opt.state &= ~QStyle::State_Enabled;
                cg = QPalette::Disabled;
            } else if (opt.state & QStyle::State_Active) {
                cg = QPalette::Active;
            } else {
                cg = QPalette::Inactive;
            }
            opt.palette.setCurrentColorGroup(cg);
        }
 
        if (alternate) {
            opt.features.setFlag(QStyleOptionViewItem::Alternate, d->current & 1);
        }
 
        /* Prior to Qt 4.3, the background of the branch (in selected state and
           alternate row color was provided by the view. For backward compatibility,
           this is now delegated to the style using PE_PanelItemViewRow which
           does the appropriate fill */
        if (d->isTreePosition(headerSection)) {
            const int i = d->indentationForItem(d->current);
            QRect branches(reverse ? position + width - i : position, y, i, height);
            const bool setClipRect = branches.width() > width;
            if (setClipRect) {
                painter->save();
                painter->setClipRect(QRect(position, y, width, height));
            }
            // draw background for the branch (selection + alternate row)
            opt.rect = branches;
 
            // We use showDecorationSelected both to store the style hint, and to indicate
            // that the entire row has to be selected (see overrides of the value if
            // selectionBehavior == SelectRow).
            // While we are only painting the background we don't care for the
            // selectionBehavior factor, so respect only the style value, and reset later.
            const bool oldShowDecorationSelected = opt.showDecorationSelected;
            opt.showDecorationSelected = style()->styleHint(QStyle::SH_ItemView_ShowDecorationSelected,
                                                            &opt, this);
            style()->drawPrimitive(QStyle::PE_PanelItemViewRow, &opt, painter, this);
 
            // draw background of the item (only alternate row). rest of the background
            // is provided by the delegate
            QStyle::State oldState = opt.state;
            opt.state &= ~QStyle::State_Selected;
            opt.rect.setRect(reverse ? position : i + position, y, width - i, height);
            style()->drawPrimitive(QStyle::PE_PanelItemViewRow, &opt, painter, this);
            opt.state = oldState;
            opt.showDecorationSelected = oldShowDecorationSelected;
 
            if (d->indent != 0)
                drawBranches(painter, branches, index);
            if (setClipRect)
                painter->restore();
        } else {
            QStyle::State oldState = opt.state;
            opt.state &= ~QStyle::State_Selected;
            opt.rect.setRect(position, y, width, height);
            style()->drawPrimitive(QStyle::PE_PanelItemViewRow, &opt, painter, this);
            opt.state = oldState;
        }
 
        itemDelegateForIndex(modelIndex)->paint(painter, opt, modelIndex);
    }
 
    if (currentRowHasFocus) {
        QStyleOptionFocusRect o;
        o.QStyleOption::operator=(option);
        o.state |= QStyle::State_KeyboardFocusChange;
        QPalette::ColorGroup cg = (option.state & QStyle::State_Enabled)
                                  ? QPalette::Normal : QPalette::Disabled;
        o.backgroundColor = option.palette.color(cg, d->selectionModel->isSelected(index)
                                                 ? QPalette::Highlight : QPalette::Window);
        int x = 0;
        if (!option.showDecorationSelected)
            x = header->sectionPosition(0) + d->indentationForItem(d->current);
        QRect focusRect(x - header->offset(), y, header->length() - x, height);
        o.rect = style()->visualRect(layoutDirection(), d->viewport->rect(), focusRect);
        style()->drawPrimitive(QStyle::PE_FrameFocusRect, &o, painter);
        // if we show focus on all columns and the first section is moved,
        // we have to split the focus rect into two rects
        if (allColumnsShowFocus && !option.showDecorationSelected
            && header->sectionsMoved() && (header->visualIndex(0) != 0)) {
            QRect sectionRect(0, y, header->sectionPosition(0), height);
            o.rect = style()->visualRect(layoutDirection(), d->viewport->rect(), sectionRect);
            style()->drawPrimitive(QStyle::PE_FrameFocusRect, &o, painter);
        }
    }
}
 
void QTreeView::drawBranches(QPainter *painter, const QRect &rect,
                             const QModelIndex &index) const
{
    Q_D(const QTreeView);
    const bool reverse = isRightToLeft();
    const int indent = d->indent;
    const int outer = d->rootDecoration ? 0 : 1;
    const int item = d->current;
    const QTreeViewItem &viewItem = d->viewItems.at(item);
    int level = viewItem.level;
    QRect primitive(reverse ? rect.left() : rect.right() + 1, rect.top(), indent, rect.height());
 
    QModelIndex parent = index.parent();
    QModelIndex current = parent;
    QModelIndex ancestor = current.parent();
 
    QStyleOptionViewItem opt;
    initViewItemOption(&opt);
    QStyle::State extraFlags = QStyle::State_None;
    if (isEnabled())
        extraFlags |= QStyle::State_Enabled;
    if (hasFocus())
        extraFlags |= QStyle::State_Active;
    QPoint oldBO = painter->brushOrigin();
    if (verticalScrollMode() == QAbstractItemView::ScrollPerPixel)
        painter->setBrushOrigin(QPoint(0, verticalOffset()));
 
    if (d->alternatingColors) {
        opt.features.setFlag(QStyleOptionViewItem::Alternate, d->current & 1);
    }
 
    // When hovering over a row, pass State_Hover for painting the branch
    // indicators if it has the decoration (aka branch) selected.
    bool hoverRow = selectionBehavior() == QAbstractItemView::SelectRows
                    && opt.showDecorationSelected
                    && index.parent() == d->hover.parent()
                    && index.row() == d->hover.row();
 
    if (d->selectionModel->isSelected(index))
        extraFlags |= QStyle::State_Selected;
 
    if (level >= outer) {
        // start with the innermost branch
        primitive.moveLeft(reverse ? primitive.left() : primitive.left() - indent);
        opt.rect = primitive;
 
        const bool expanded = viewItem.expanded;
        const bool children = viewItem.hasChildren;
        bool moreSiblings = viewItem.hasMoreSiblings;
 
        opt.state = QStyle::State_Item | extraFlags
                    | (moreSiblings ? QStyle::State_Sibling : QStyle::State_None)
                    | (children ? QStyle::State_Children : QStyle::State_None)
                    | (expanded ? QStyle::State_Open : QStyle::State_None);
        opt.state.setFlag(QStyle::State_MouseOver, hoverRow || item == d->hoverBranch);
 
        style()->drawPrimitive(QStyle::PE_IndicatorBranch, &opt, painter, this);
    }
    // then go out level by level
    for (--level; level >= outer; --level) { // we have already drawn the innermost branch
        primitive.moveLeft(reverse ? primitive.left() + indent : primitive.left() - indent);
        opt.rect = primitive;
        opt.state = extraFlags;
        bool moreSiblings = false;
        if (d->hiddenIndexes.isEmpty()) {
            moreSiblings = (d->model->rowCount(ancestor) - 1 > current.row());
        } else {
            int successor = item + viewItem.total + 1;
            while (successor < d->viewItems.size()
                   && d->viewItems.at(successor).level >= uint(level)) {
                const QTreeViewItem &successorItem = d->viewItems.at(successor);
                if (successorItem.level == uint(level)) {
                    moreSiblings = true;
                    break;
                }
                successor += successorItem.total + 1;
            }
        }
        if (moreSiblings)
            opt.state |= QStyle::State_Sibling;
        opt.state.setFlag(QStyle::State_MouseOver, hoverRow || item == d->hoverBranch);
 
        style()->drawPrimitive(QStyle::PE_IndicatorBranch, &opt, painter, this);
        current = ancestor;
        ancestor = current.parent();
    }
    painter->setBrushOrigin(oldBO);
}
 
void QTreeView::mousePressEvent(QMouseEvent *event)
{
    Q_D(QTreeView);
    bool handled = false;
    if (style()->styleHint(QStyle::SH_ListViewExpand_SelectMouseType, nullptr, this) == QEvent::MouseButtonPress)
        handled = d->expandOrCollapseItemAtPos(event->position().toPoint());
    if (!handled && d->itemDecorationAt(event->position().toPoint()) == -1)
        QAbstractItemView::mousePressEvent(event);
    else
        d->pressedIndex = QModelIndex();
}
 
void QTreeView::mouseReleaseEvent(QMouseEvent *event)
{
    Q_D(QTreeView);
    if (d->itemDecorationAt(event->position().toPoint()) == -1) {
        QAbstractItemView::mouseReleaseEvent(event);
    } else {
        if (state() == QAbstractItemView::DragSelectingState || state() == QAbstractItemView::DraggingState)
            setState(QAbstractItemView::NoState);
        if (style()->styleHint(QStyle::SH_ListViewExpand_SelectMouseType, nullptr, this) == QEvent::MouseButtonRelease)
            d->expandOrCollapseItemAtPos(event->position().toPoint());
    }
}
 
void QTreeView::mouseDoubleClickEvent(QMouseEvent *event)
{
    Q_D(QTreeView);
    if (state() != NoState || !d->viewport->rect().contains(event->position().toPoint()))
        return;
 
    int i = d->itemDecorationAt(event->position().toPoint());
    if (i == -1) {
        i = d->itemAtCoordinate(event->position().toPoint().y());
        if (i == -1)
            return; // user clicked outside the items
 
        const QPersistentModelIndex firstColumnIndex = d->viewItems.at(i).index;
        const QPersistentModelIndex persistent = indexAt(event->position().toPoint());
 
        if (d->pressedIndex != persistent) {
            mousePressEvent(event);
            return;
        }
 
        // signal handlers may change the model
        emit doubleClicked(persistent);
 
        if (!persistent.isValid())
            return;
 
        if (edit(persistent, DoubleClicked, event) || state() != NoState)
            return; // the double click triggered editing
 
        if (!style()->styleHint(QStyle::SH_ItemView_ActivateItemOnSingleClick, nullptr, this))
            emit activated(persistent);
 
        d->releaseFromDoubleClick = true;
        d->executePostedLayout(); // we need to make sure viewItems is updated
        if (d->itemsExpandable
            && d->expandsOnDoubleClick
            && d->hasVisibleChildren(persistent)) {
            if (!((i < d->viewItems.size()) && (d->viewItems.at(i).index == firstColumnIndex))) {
                // find the new index of the item
                for (i = 0; i < d->viewItems.size(); ++i) {
                    if (d->viewItems.at(i).index == firstColumnIndex)
                        break;
                }
                if (i == d->viewItems.size())
                    return;
            }
            if (d->viewItems.at(i).expanded)
                d->collapse(i, true);
            else
                d->expand(i, true);
            updateGeometries();
            viewport()->update();
        }
    }
}
 
void QTreeView::mouseMoveEvent(QMouseEvent *event)
{
    Q_D(QTreeView);
    if (d->itemDecorationAt(event->position().toPoint()) == -1) // ### what about expanding/collapsing state ?
        QAbstractItemView::mouseMoveEvent(event);
}
 
void QTreeView::keyPressEvent(QKeyEvent *event)
{
    Q_D(QTreeView);
    QModelIndex current = currentIndex();
    //this is the management of the expansion
    if (d->isIndexValid(current) && d->model && d->itemsExpandable) {
        switch (event->key()) {
        case Qt::Key_Asterisk: {
            expandRecursively(current);
            break; }
        case Qt::Key_Plus:
            expand(current);
            break;
        case Qt::Key_Minus:
            collapse(current);
            break;
        }
    }
 
    QAbstractItemView::keyPressEvent(event);
}
 
QModelIndex QTreeView::indexAt(const QPoint &point) const
{
    Q_D(const QTreeView);
    d->executePostedLayout();
 
    int visualIndex = d->itemAtCoordinate(point.y());
    QModelIndex idx = d->modelIndex(visualIndex);
    if (!idx.isValid())
        return QModelIndex();
 
    if (d->viewItems.at(visualIndex).spanning)
        return idx;
 
    int column = d->columnAt(point.x());
    if (column == idx.column())
        return idx;
    if (column < 0)
        return QModelIndex();
    return idx.sibling(idx.row(), column);
}
 
QModelIndex QTreeView::indexAbove(const QModelIndex &index) const
{
    Q_D(const QTreeView);
    if (!d->isIndexValid(index))
        return QModelIndex();
    d->executePostedLayout();
    int i = d->viewIndex(index);
    if (--i < 0)
        return QModelIndex();
    const QModelIndex firstColumnIndex = d->viewItems.at(i).index;
    return firstColumnIndex.sibling(firstColumnIndex.row(), index.column());
}
 
QModelIndex QTreeView::indexBelow(const QModelIndex &index) const
{
    Q_D(const QTreeView);
    if (!d->isIndexValid(index))
        return QModelIndex();
    d->executePostedLayout();
    int i = d->viewIndex(index);
    if (++i >= d->viewItems.size())
        return QModelIndex();
    const QModelIndex firstColumnIndex = d->viewItems.at(i).index;
    return firstColumnIndex.sibling(firstColumnIndex.row(), index.column());
}
 
void QTreeView::doItemsLayout()
{
    Q_D(QTreeView);
    if (d->hasRemovedItems) {
        //clean the QSet that may contains old (and this invalid) indexes
        d->hasRemovedItems = false;
        QSet<QPersistentModelIndex>::iterator it = d->expandedIndexes.begin();
        while (it != d->expandedIndexes.end()) {
            if (!it->isValid())
                it = d->expandedIndexes.erase(it);
            else
                ++it;
        }
        it = d->hiddenIndexes.begin();
        while (it != d->hiddenIndexes.end()) {
            if (!it->isValid())
                it = d->hiddenIndexes.erase(it);
            else
                ++it;
        }
    }
    d->viewItems.clear(); // prepare for new layout
    QModelIndex parent = d->root;
    if (d->model->hasChildren(parent)) {
        d->layout(-1);
    }
    QAbstractItemView::doItemsLayout();
    d->header->doItemsLayout();
    d->updateAccessibility();
}
 
void QTreeView::reset()
{
    Q_D(QTreeView);
    d->expandedIndexes.clear();
    d->hiddenIndexes.clear();
    d->spanningIndexes.clear();
    d->viewItems.clear();
    QAbstractItemView::reset();
}
 
int QTreeView::horizontalOffset() const
{
    Q_D(const QTreeView);
    return d->header->offset();
}
 
int QTreeView::verticalOffset() const
{
    Q_D(const QTreeView);
    if (d->verticalScrollMode == QAbstractItemView::ScrollPerItem) {
        if (d->uniformRowHeights)
            return verticalScrollBar()->value() * d->defaultItemHeight;
        // If we are scrolling per item and have non-uniform row heights,
        // finding the vertical offset in pixels is going to be relatively slow.
        // ### find a faster way to do this
        d->executePostedLayout();
        int offset = 0;
        const int cnt = qMin(d->viewItems.size(), verticalScrollBar()->value());
        for (int i = 0; i < cnt; ++i)
            offset += d->itemHeight(i);
        return offset;
    }
    // scroll per pixel
    return verticalScrollBar()->value();
}
 
QModelIndex QTreeView::moveCursor(CursorAction cursorAction, Qt::KeyboardModifiers modifiers)
{
    Q_D(QTreeView);
    Q_UNUSED(modifiers);
 
    d->executePostedLayout();
 
    QModelIndex current = currentIndex();
    if (!current.isValid()) {
        int i = d->below(-1);
        int c = 0;
        while (c < d->header->count() && d->header->isSectionHidden(d->header->logicalIndex(c)))
            ++c;
        if (i < d->viewItems.size() && c < d->header->count()) {
            return d->modelIndex(i, d->header->logicalIndex(c));
        }
        return QModelIndex();
    }
 
    const int vi = qMax(0, d->viewIndex(current));
 
    if (isRightToLeft()) {
        if (cursorAction == MoveRight)
            cursorAction = MoveLeft;
        else if (cursorAction == MoveLeft)
            cursorAction = MoveRight;
    }
    switch (cursorAction) {
    case MoveNext:
    case MoveDown:
#ifdef QT_KEYPAD_NAVIGATION
        if (vi == d->viewItems.count()-1 && QApplicationPrivate::keypadNavigationEnabled())
            return d->model->index(0, current.column(), d->root);
#endif
        return d->modelIndex(d->below(vi), current.column());
    case MovePrevious:
    case MoveUp:
#ifdef QT_KEYPAD_NAVIGATION
        if (vi == 0 && QApplicationPrivate::keypadNavigationEnabled())
            return d->modelIndex(d->viewItems.count() - 1, current.column());
#endif
        return d->modelIndex(d->above(vi), current.column());
    case MoveLeft: {
        QScrollBar *sb = horizontalScrollBar();
        if (vi < d->viewItems.size() && d->viewItems.at(vi).expanded && d->itemsExpandable && sb->value() == sb->minimum()) {
            d->collapse(vi, true);
            d->moveCursorUpdatedView = true;
        } else {
            bool descend = style()->styleHint(QStyle::SH_ItemView_ArrowKeysNavigateIntoChildren, nullptr, this);
            if (descend) {
                QModelIndex par = current.parent();
                if (par.isValid() && par != rootIndex())
                    return par;
                else
                    descend = false;
            }
            if (!descend) {
                if (d->selectionBehavior == SelectItems || d->selectionBehavior == SelectColumns) {
                    int visualColumn = d->header->visualIndex(current.column()) - 1;
                    while (visualColumn >= 0 && isColumnHidden(d->header->logicalIndex(visualColumn)))
                        visualColumn--;
                    int newColumn = d->header->logicalIndex(visualColumn);
                    QModelIndex next = current.sibling(current.row(), newColumn);
                    if (next.isValid())
                        return next;
                }
 
                int oldValue = sb->value();
                sb->setValue(sb->value() - sb->singleStep());
                if (oldValue != sb->value())
                    d->moveCursorUpdatedView = true;
            }
 
        }
        updateGeometries();
        viewport()->update();
        break;
    }
    case MoveRight:
        if (vi < d->viewItems.size() && !d->viewItems.at(vi).expanded && d->itemsExpandable
            && d->hasVisibleChildren(d->viewItems.at(vi).index)) {
            d->expand(vi, true);
            d->moveCursorUpdatedView = true;
        } else {
            bool descend = style()->styleHint(QStyle::SH_ItemView_ArrowKeysNavigateIntoChildren, nullptr, this);
            if (descend) {
                QModelIndex idx = d->modelIndex(d->below(vi));
                if (idx.parent() == current)
                    return idx;
                else
                    descend = false;
            }
            if (!descend) {
                if (d->selectionBehavior == SelectItems || d->selectionBehavior == SelectColumns) {
                    int visualColumn = d->header->visualIndex(current.column()) + 1;
                    while (visualColumn < d->model->columnCount(current.parent()) && isColumnHidden(d->header->logicalIndex(visualColumn)))
                        visualColumn++;
                    const int newColumn = d->header->logicalIndex(visualColumn);
                    const QModelIndex next = current.sibling(current.row(), newColumn);
                    if (next.isValid())
                        return next;
                }
 
                //last restort: we change the scrollbar value
                QScrollBar *sb = horizontalScrollBar();
                int oldValue = sb->value();
                sb->setValue(sb->value() + sb->singleStep());
                if (oldValue != sb->value())
                    d->moveCursorUpdatedView = true;
            }
        }
        updateGeometries();
        viewport()->update();
        break;
    case MovePageUp:
        return d->modelIndex(d->pageUp(vi), current.column());
    case MovePageDown:
        return d->modelIndex(d->pageDown(vi), current.column());
    case MoveHome:
        return d->modelIndex(d->itemForKeyHome(), current.column());
    case MoveEnd:
        return d->modelIndex(d->itemForKeyEnd(), current.column());
    }
    return current;
}
 
void QTreeView::setSelection(const QRect &rect, QItemSelectionModel::SelectionFlags command)
{
    Q_D(QTreeView);
    if (!selectionModel() || rect.isNull())
        return;
 
    d->executePostedLayout();
    QPoint tl(isRightToLeft() ? qMax(rect.left(), rect.right())
              : qMin(rect.left(), rect.right()), qMin(rect.top(), rect.bottom()));
    QPoint br(isRightToLeft() ? qMin(rect.left(), rect.right()) :
              qMax(rect.left(), rect.right()), qMax(rect.top(), rect.bottom()));
    QModelIndex topLeft = indexAt(tl);
    QModelIndex bottomRight = indexAt(br);
    if (!topLeft.isValid() && !bottomRight.isValid()) {
        if (command & QItemSelectionModel::Clear)
            selectionModel()->clear();
        return;
    }
    if (!topLeft.isValid() && !d->viewItems.isEmpty())
        topLeft = d->viewItems.constFirst().index;
    if (!bottomRight.isValid() && !d->viewItems.isEmpty()) {
        const int column = d->header->logicalIndex(d->header->count() - 1);
        const QModelIndex index = d->viewItems.constLast().index;
        bottomRight = index.sibling(index.row(), column);
    }
 
    if (!d->isIndexEnabled(topLeft) || !d->isIndexEnabled(bottomRight))
        return;
 
    d->select(topLeft, bottomRight, command);
}
 
QRegion QTreeView::visualRegionForSelection(const QItemSelection &selection) const
{
    Q_D(const QTreeView);
    if (selection.isEmpty())
        return QRegion();
 
    QRegion selectionRegion;
    const QRect &viewportRect = d->viewport->rect();
    for (const auto &range : selection) {
        if (!range.isValid())
            continue;
        QModelIndex parent = range.parent();
        QModelIndex leftIndex = range.topLeft();
        int columnCount = d->model->columnCount(parent);
        while (leftIndex.isValid() && isIndexHidden(leftIndex)) {
            if (leftIndex.column() + 1 < columnCount)
                leftIndex = d->model->index(leftIndex.row(), leftIndex.column() + 1, parent);
            else
                leftIndex = QModelIndex();
        }
        if (!leftIndex.isValid())
            continue;
        const QRect leftRect = d->visualRect(leftIndex, QTreeViewPrivate::SingleSection);
        int top = leftRect.top();
        QModelIndex rightIndex = range.bottomRight();
        while (rightIndex.isValid() && isIndexHidden(rightIndex)) {
            if (rightIndex.column() - 1 >= 0)
                rightIndex = d->model->index(rightIndex.row(), rightIndex.column() - 1, parent);
            else
                rightIndex = QModelIndex();
        }
        if (!rightIndex.isValid())
            continue;
        const QRect rightRect = d->visualRect(rightIndex, QTreeViewPrivate::SingleSection);
        int bottom = rightRect.bottom();
        if (top > bottom)
            qSwap<int>(top, bottom);
        int height = bottom - top + 1;
        if (d->header->sectionsMoved()) {
            for (int c = range.left(); c <= range.right(); ++c) {
                const QRect rangeRect(columnViewportPosition(c), top, columnWidth(c), height);
                if (viewportRect.intersects(rangeRect))
                    selectionRegion += rangeRect;
            }
        } else {
            QRect combined = leftRect|rightRect;
            combined.setX(columnViewportPosition(isRightToLeft() ? range.right() : range.left()));
            if (viewportRect.intersects(combined))
                selectionRegion += combined;
        }
    }
    return selectionRegion;
}
 
QModelIndexList QTreeView::selectedIndexes() const
{
    QModelIndexList viewSelected;
    QModelIndexList modelSelected;
    if (selectionModel())
        modelSelected = selectionModel()->selectedIndexes();
    for (int i = 0; i < modelSelected.size(); ++i) {
        // check that neither the parents nor the index is hidden before we add
        QModelIndex index = modelSelected.at(i);
        while (index.isValid() && !isIndexHidden(index))
            index = index.parent();
        if (index.isValid())
            continue;
        viewSelected.append(modelSelected.at(i));
    }
    return viewSelected;
}
 
void QTreeView::scrollContentsBy(int dx, int dy)
{
    Q_D(QTreeView);
 
    d->delayedAutoScroll.stop(); // auto scroll was canceled by the user scrolling
 
    dx = isRightToLeft() ? -dx : dx;
    if (dx) {
        int oldOffset = d->header->offset();
        d->header->d_func()->setScrollOffset(horizontalScrollBar(), horizontalScrollMode());
        if (horizontalScrollMode() == QAbstractItemView::ScrollPerItem) {
            int newOffset = d->header->offset();
            dx = isRightToLeft() ? newOffset - oldOffset : oldOffset - newOffset;
        }
    }
 
    const int itemHeight = d->defaultItemHeight <= 0 ? sizeHintForRow(0) : d->defaultItemHeight;
    if (d->viewItems.isEmpty() || itemHeight == 0)
        return;
 
    // guestimate the number of items in the viewport
    int viewCount = d->viewport->height() / itemHeight;
    int maxDeltaY = qMin(d->viewItems.size(), viewCount);
    // no need to do a lot of work if we are going to redraw the whole thing anyway
    if (qAbs(dy) > qAbs(maxDeltaY) && d->editorIndexHash.isEmpty()) {
        verticalScrollBar()->update();
        d->viewport->update();
        return;
    }
 
    if (dy && verticalScrollMode() == QAbstractItemView::ScrollPerItem) {
        int currentScrollbarValue = verticalScrollBar()->value();
        int previousScrollbarValue = currentScrollbarValue + dy; // -(-dy)
        int currentViewIndex = currentScrollbarValue; // the first visible item
        int previousViewIndex = previousScrollbarValue;
        dy = 0;
        if (previousViewIndex < currentViewIndex) { // scrolling down
            for (int i = previousViewIndex; i < currentViewIndex; ++i) {
                if (i < d->viewItems.size())
                    dy -= d->itemHeight(i);
            }
        } else if (previousViewIndex > currentViewIndex) { // scrolling up
            for (int i = previousViewIndex - 1; i >= currentViewIndex; --i) {
                if (i < d->viewItems.size())
                    dy += d->itemHeight(i);
            }
        }
    }
 
    d->scrollContentsBy(dx, dy);
}
 
void QTreeView::columnMoved()
{
    Q_D(QTreeView);
    updateEditorGeometries();
    d->viewport->update();
}
 
void QTreeView::reexpand()
{
    // do nothing
}
 
void QTreeView::rowsInserted(const QModelIndex &parent, int start, int end)
{
    Q_D(QTreeView);
    // if we are going to do a complete relayout anyway, there is no need to update
    if (d->delayedPendingLayout) {
        QAbstractItemView::rowsInserted(parent, start, end);
        return;
    }
 
    //don't add a hierarchy on a column != 0
    if (parent.column() != 0 && parent.isValid()) {
        QAbstractItemView::rowsInserted(parent, start, end);
        return;
    }
 
    const int parentRowCount = d->model->rowCount(parent);
    const int delta = end - start + 1;
    if (parent != d->root && !d->isIndexExpanded(parent) && parentRowCount > delta) {
        QAbstractItemView::rowsInserted(parent, start, end);
        return;
    }
 
    const int parentItem = d->viewIndex(parent);
    if (((parentItem != -1) && d->viewItems.at(parentItem).expanded)
        || (parent == d->root)) {
        d->doDelayedItemsLayout();
    } else if (parentItem != -1 && parentRowCount == delta) {
        // the parent just went from 0 children to more. update to re-paint the decoration
        d->viewItems[parentItem].hasChildren = true;
        viewport()->update();
    }
    QAbstractItemView::rowsInserted(parent, start, end);
}
 
void QTreeView::rowsAboutToBeRemoved(const QModelIndex &parent, int start, int end)
{
    Q_D(QTreeView);
    QAbstractItemView::rowsAboutToBeRemoved(parent, start, end);
    d->viewItems.clear();
}
 
void QTreeView::rowsRemoved(const QModelIndex &parent, int start, int end)
{
    Q_D(QTreeView);
    d->viewItems.clear();
    d->doDelayedItemsLayout();
    d->hasRemovedItems = true;
    d->rowsRemoved(parent, start, end);
}
 
void QTreeView::columnCountChanged(int oldCount, int newCount)
{
    Q_D(QTreeView);
    if (oldCount == 0 && newCount > 0) {
        //if the first column has just been added we need to relayout.
        d->doDelayedItemsLayout();
    }
 
    if (isVisible())
        updateGeometries();
    viewport()->update();
}
 
void QTreeView::resizeColumnToContents(int column)
{
    Q_D(QTreeView);
    d->executePostedLayout();
    if (column < 0 || column >= d->header->count())
        return;
    int contents = sizeHintForColumn(column);
    int header = d->header->isHidden() ? 0 : d->header->sectionSizeHint(column);
    d->header->resizeSection(column, qMax(contents, header));
}
 
void QTreeView::sortByColumn(int column, Qt::SortOrder order)
{
    Q_D(QTreeView);
    if (column < -1)
        return;
    d->header->setSortIndicator(column, order);
    // If sorting is not enabled or has the same order as before, force to sort now
    // else sorting will be trigger through sortIndicatorChanged()
    if (!d->sortingEnabled ||
        (d->header->sortIndicatorSection() == column && d->header->sortIndicatorOrder() == order))
        d->model->sort(column, order);
}
 
void QTreeView::selectAll()
{
    Q_D(QTreeView);
    if (!selectionModel())
        return;
    SelectionMode mode = d->selectionMode;
    d->executePostedLayout(); //make sure we lay out the items
    if (mode != SingleSelection && mode != NoSelection && !d->viewItems.isEmpty()) {
        const QModelIndex &idx = d->viewItems.constLast().index;
        QModelIndex lastItemIndex = idx.sibling(idx.row(), d->model->columnCount(idx.parent()) - 1);
        d->select(d->viewItems.constFirst().index, lastItemIndex,
                  QItemSelectionModel::ClearAndSelect
                  |QItemSelectionModel::Rows);
    }
}
 
QSize QTreeView::viewportSizeHint() const
{
    Q_D(const QTreeView);
    d->executePostedLayout(); // Make sure that viewItems are up to date.
 
    if (d->viewItems.size() == 0)
        return QAbstractItemView::viewportSizeHint();
 
    // Get rect for last item
    const QRect deepestRect = d->visualRect(d->viewItems.last().index,
                                            QTreeViewPrivate::SingleSection);
 
    if (!deepestRect.isValid())
        return QAbstractItemView::viewportSizeHint();
 
    QSize result = QSize(d->header->length(), deepestRect.bottom() + 1);
 
    // add size for header
    result += QSize(0, d->header->isHidden() ? 0 : d->header->height());
 
    return result;
}
 
void QTreeView::expandAll()
{
    Q_D(QTreeView);
    d->viewItems.clear();
    d->interruptDelayedItemsLayout();
    d->layout(-1, true);
    updateGeometries();
    d->viewport->update();
    d->updateAccessibility();
}
 
void QTreeView::expandRecursively(const QModelIndex &index, int depth)
{
    Q_D(QTreeView);
 
    if (depth < -1)
        return;
    // do layouting only once after expanding is done
    d->doDelayedItemsLayout();
    expand(index);
    if (depth == 0)
        return;
    QStack<QPair<QModelIndex, int>> parents;
    parents.push({index, 0});
    while (!parents.isEmpty()) {
        const QPair<QModelIndex, int> elem = parents.pop();
        const QModelIndex &parent = elem.first;
        const int curDepth = elem.second;
        const int rowCount = d->model->rowCount(parent);
        for (int row = 0; row < rowCount; ++row) {
            const QModelIndex child = d->model->index(row, 0, parent);
            if (!d->isIndexValid(child))
                break;
            if (depth == -1 || curDepth + 1 < depth)
                parents.push({child, curDepth + 1});
            if (d->isIndexExpanded(child))
                continue;
            if (d->storeExpanded(child))
                emit expanded(child);
        }
    }
}
 
void QTreeView::collapseAll()
{
    Q_D(QTreeView);
    QSet<QPersistentModelIndex> old_expandedIndexes;
    old_expandedIndexes = d->expandedIndexes;
    d->expandedIndexes.clear();
    if (!signalsBlocked() && isSignalConnected(QMetaMethod::fromSignal(&QTreeView::collapsed))) {
        QSet<QPersistentModelIndex>::const_iterator i = old_expandedIndexes.constBegin();
        for (; i != old_expandedIndexes.constEnd(); ++i) {
            const QPersistentModelIndex &mi = (*i);
            if (mi.isValid() && !(mi.flags() & Qt::ItemNeverHasChildren))
                emit collapsed(mi);
        }
    }
    doItemsLayout();
}
 
void QTreeView::expandToDepth(int depth)
{
    Q_D(QTreeView);
    d->viewItems.clear();
    QSet<QPersistentModelIndex> old_expandedIndexes;
    old_expandedIndexes = d->expandedIndexes;
    d->expandedIndexes.clear();
    d->interruptDelayedItemsLayout();
    d->layout(-1);
    for (int i = 0; i < d->viewItems.size(); ++i) {
        if (d->viewItems.at(i).level <= (uint)depth) {
            d->viewItems[i].expanded = true;
            d->layout(i);
            d->storeExpanded(d->viewItems.at(i).index);
        }
    }
 
    bool someSignalEnabled = isSignalConnected(QMetaMethod::fromSignal(&QTreeView::collapsed));
    someSignalEnabled |= isSignalConnected(QMetaMethod::fromSignal(&QTreeView::expanded));
 
    if (!signalsBlocked() && someSignalEnabled) {
        // emit signals
        QSet<QPersistentModelIndex> collapsedIndexes = old_expandedIndexes - d->expandedIndexes;
        QSet<QPersistentModelIndex>::const_iterator i = collapsedIndexes.constBegin();
        for (; i != collapsedIndexes.constEnd(); ++i) {
            const QPersistentModelIndex &mi = (*i);
            if (mi.isValid() && !(mi.flags() & Qt::ItemNeverHasChildren))
                emit collapsed(mi);
        }
 
        QSet<QPersistentModelIndex> expandedIndexs = d->expandedIndexes - old_expandedIndexes;
        i = expandedIndexs.constBegin();
        for (; i != expandedIndexs.constEnd(); ++i) {
            const QPersistentModelIndex &mi = (*i);
            if (mi.isValid() && !(mi.flags() & Qt::ItemNeverHasChildren))
                emit expanded(mi);
        }
    }
 
    updateGeometries();
    d->viewport->update();
    d->updateAccessibility();
}
 
void QTreeView::columnResized(int column, int /* oldSize */, int /* newSize */)
{
    Q_D(QTreeView);
    d->columnsToUpdate.append(column);
    if (d->columnResizeTimerID == 0)
        d->columnResizeTimerID = startTimer(0);
}
 
void QTreeView::updateGeometries()
{
    Q_D(QTreeView);
    if (d->header) {
        if (d->geometryRecursionBlock)
            return;
        d->geometryRecursionBlock = true;
        int height = 0;
        if (!d->header->isHidden()) {
            height = qMax(d->header->minimumHeight(), d->header->sizeHint().height());
            height = qMin(height, d->header->maximumHeight());
        }
        setViewportMargins(0, height, 0, 0);
        QRect vg = d->viewport->geometry();
        QRect geometryRect(vg.left(), vg.top() - height, vg.width(), height);
        d->header->setGeometry(geometryRect);
        QMetaObject::invokeMethod(d->header, "updateGeometries");
        d->updateScrollBars();
        d->geometryRecursionBlock = false;
    }
    QAbstractItemView::updateGeometries();
}
 
int QTreeView::sizeHintForColumn(int column) const
{
    Q_D(const QTreeView);
    d->executePostedLayout();
    if (d->viewItems.isEmpty())
        return -1;
    ensurePolished();
    int w = 0;
    QStyleOptionViewItem option;
    initViewItemOption(&option);
    const QList<QTreeViewItem> viewItems = d->viewItems;
 
    const int maximumProcessRows = d->header->resizeContentsPrecision(); // To avoid this to take forever.
 
    int offset = 0;
    int start = d->firstVisibleItem(&offset);
    int end = d->lastVisibleItem(start, offset);
    if (start < 0 || end < 0 || end == viewItems.size() - 1) {
        end = viewItems.size() - 1;
        if (maximumProcessRows < 0) {
            start = 0;
        } else if (maximumProcessRows == 0) {
            start = qMax(0, end - 1);
            int remainingHeight = viewport()->height();
            while (start > 0 && remainingHeight > 0) {
                remainingHeight -= d->itemHeight(start);
                --start;
            }
        } else {
            start = qMax(0, end - maximumProcessRows);
        }
    }
 
    int rowsProcessed = 0;
 
    for (int i = start; i <= end; ++i) {
        if (viewItems.at(i).spanning)
            continue; // we have no good size hint
        QModelIndex index = viewItems.at(i).index;
        index = index.sibling(index.row(), column);
        w = d->widthHintForIndex(index, w, option, i);
        ++rowsProcessed;
        if (rowsProcessed == maximumProcessRows)
            break;
    }
 
    --end;
    int actualBottom = viewItems.size() - 1;
 
    if (maximumProcessRows == 0)
        rowsProcessed = 0; // skip the while loop
 
    while (rowsProcessed != maximumProcessRows && (start > 0 || end < actualBottom)) {
        int idx  = -1;
 
        if ((rowsProcessed % 2 && start > 0) || end == actualBottom) {
            while (start > 0) {
                --start;
                if (viewItems.at(start).spanning)
                    continue;
                idx = start;
                break;
            }
        } else {
            while (end < actualBottom) {
                ++end;
                if (viewItems.at(end).spanning)
                    continue;
                idx = end;
                break;
            }
        }
        if (idx < 0)
            continue;
 
        QModelIndex index = viewItems.at(idx).index;
        index = index.sibling(index.row(), column);
        w = d->widthHintForIndex(index, w, option, idx);
        ++rowsProcessed;
    }
    return w;
}
 
int QTreeView::indexRowSizeHint(const QModelIndex &index) const
{
    Q_D(const QTreeView);
    if (!d->isIndexValid(index) || !d->itemDelegate)
        return 0;
 
    int start = -1;
    int end = -1;
    int indexRow = index.row();
    int count = d->header->count();
    bool emptyHeader = (count == 0);
    QModelIndex parent = index.parent();
 
    if (count && isVisible()) {
        // If the sections have moved, we end up checking too many or too few
        start = d->header->visualIndexAt(0);
    } else {
        // If the header has not been laid out yet, we use the model directly
        count = d->model->columnCount(parent);
    }
 
    if (isRightToLeft()) {
        start = (start == -1 ? count - 1 : start);
        end = 0;
    } else {
        start = (start == -1 ? 0 : start);
        end = count - 1;
    }
 
    if (end < start)
        qSwap(end, start);
 
    int height = -1;
    QStyleOptionViewItem option;
    initViewItemOption(&option);
   // ### If we want word wrapping in the items,
    // ### we need to go through all the columns
    // ### and set the width of the column
 
    // Hack to speed up the function
    option.rect.setWidth(-1);
 
    for (int column = start; column <= end; ++column) {
        int logicalColumn = emptyHeader ? column : d->header->logicalIndex(column);
        if (d->header->isSectionHidden(logicalColumn))
            continue;
        QModelIndex idx = d->model->index(indexRow, logicalColumn, parent);
        if (idx.isValid()) {
            QWidget *editor = d->editorForIndex(idx).widget.data();
            if (editor && d->persistent.contains(editor)) {
                height = qMax(height, editor->sizeHint().height());
                int min = editor->minimumSize().height();
                int max = editor->maximumSize().height();
                height = qBound(min, height, max);
            }
            int hint = itemDelegateForIndex(idx)->sizeHint(option, idx).height();
            height = qMax(height, hint);
        }
    }
 
    return height;
}
 
int QTreeView::rowHeight(const QModelIndex &index) const
{
    Q_D(const QTreeView);
    d->executePostedLayout();
    int i = d->viewIndex(index);
    if (i == -1)
        return 0;
    return d->itemHeight(i);
}
 
void QTreeView::horizontalScrollbarAction(int action)
{
    QAbstractItemView::horizontalScrollbarAction(action);
}
 
bool QTreeView::isIndexHidden(const QModelIndex &index) const
{
    return (isColumnHidden(index.column()) || isRowHidden(index.row(), index.parent()));
}
 
/*
  private implementation
*/
void QTreeViewPrivate::initialize()
{
    Q_Q(QTreeView);
 
    updateIndentationFromStyle();
    updateStyledFrameWidths();
    q->setSelectionBehavior(QAbstractItemView::SelectRows);
    q->setSelectionMode(QAbstractItemView::SingleSelection);
    q->setHorizontalScrollMode(QAbstractItemView::ScrollPerPixel);
    q->setAttribute(Qt::WA_MacShowFocusRect);
 
    QHeaderView *header = new QHeaderView(Qt::Horizontal, q);
    header->setSectionsMovable(true);
    header->setStretchLastSection(true);
    header->setDefaultAlignment(Qt::AlignLeft|Qt::AlignVCenter);
    q->setHeader(header);
#if QT_CONFIG(animation)
    animationsEnabled = q->style()->styleHint(QStyle::SH_Widget_Animation_Duration, nullptr, q) > 0;
    animationConnection =
        QObjectPrivate::connect(&animatedOperation, &QVariantAnimation::finished,
                                this, &QTreeViewPrivate::endAnimatedOperation);
#endif // animation
}
 
void QTreeViewPrivate::clearConnections()
{
    for (const QMetaObject::Connection &connection : modelConnections)
        QObject::disconnect(connection);
    for (const QMetaObject::Connection &connection : headerConnections)
        QObject::disconnect(connection);
    QObject::disconnect(selectionmodelConnection);
    QObject::disconnect(sortHeaderConnection);
#if QT_CONFIG(animation)
    QObject::disconnect(animationConnection);
#endif
}
 
void QTreeViewPrivate::expand(int item, bool emitSignal)
{
    Q_Q(QTreeView);
 
    if (item == -1 || viewItems.at(item).expanded)
        return;
    const QModelIndex index = viewItems.at(item).index;
    if (index.flags() & Qt::ItemNeverHasChildren)
        return;
 
#if QT_CONFIG(animation)
    if (emitSignal && animationsEnabled)
        prepareAnimatedOperation(item, QVariantAnimation::Forward);
#endif // animation
     //if already animating, stateBeforeAnimation is set to the correct value
    if (state != QAbstractItemView::AnimatingState)
        stateBeforeAnimation = state;
    q->setState(QAbstractItemView::ExpandingState);
    storeExpanded(index);
    viewItems[item].expanded = true;
    layout(item);
    q->setState(stateBeforeAnimation);
 
    if (model->canFetchMore(index))
        model->fetchMore(index);
    if (emitSignal) {
        emit q->expanded(index);
#if QT_CONFIG(animation)
        if (animationsEnabled)
            beginAnimatedOperation();
#endif // animation
    }
    updateAccessibility();
}
 
void QTreeViewPrivate::insertViewItems(int pos, int count, const QTreeViewItem &viewItem)
{
    viewItems.insert(pos, count, viewItem);
    QTreeViewItem *items = viewItems.data();
    for (int i = pos + count; i < viewItems.size(); i++)
        if (items[i].parentItem >= pos)
            items[i].parentItem += count;
}
 
void QTreeViewPrivate::removeViewItems(int pos, int count)
{
    viewItems.remove(pos, count);
    QTreeViewItem *items = viewItems.data();
    for (int i = pos; i < viewItems.size(); i++)
        if (items[i].parentItem >= pos)
            items[i].parentItem -= count;
}
 
#if 0
bool QTreeViewPrivate::checkViewItems() const
{
    for (int i = 0; i < viewItems.count(); ++i) {
        const QTreeViewItem &vi = viewItems.at(i);
        if (vi.parentItem == -1) {
            Q_ASSERT(!vi.index.parent().isValid() || vi.index.parent() == root);
        } else {
            Q_ASSERT(vi.index.parent() == viewItems.at(vi.parentItem).index);
        }
    }
    return true;
}
#endif
 
void QTreeViewPrivate::collapse(int item, bool emitSignal)
{
    Q_Q(QTreeView);
 
    if (item == -1 || expandedIndexes.isEmpty())
        return;
 
    //if the current item is now invisible, the autoscroll will expand the tree to see it, so disable the autoscroll
    delayedAutoScroll.stop();
 
    int total = viewItems.at(item).total;
    const QModelIndex &modelIndex = viewItems.at(item).index;
    if (!isPersistent(modelIndex))
        return; // if the index is not persistent, no chances it is expanded
    QSet<QPersistentModelIndex>::iterator it = expandedIndexes.find(modelIndex);
    if (it == expandedIndexes.end() || viewItems.at(item).expanded == false)
        return; // nothing to do
 
#if QT_CONFIG(animation)
    if (emitSignal && animationsEnabled)
        prepareAnimatedOperation(item, QVariantAnimation::Backward);
#endif // animation
 
    //if already animating, stateBeforeAnimation is set to the correct value
    if (state != QAbstractItemView::AnimatingState)
        stateBeforeAnimation = state;
    q->setState(QAbstractItemView::CollapsingState);
    expandedIndexes.erase(it);
    viewItems[item].expanded = false;
    int index = item;
    while (index > -1) {
        viewItems[index].total -= total;
        index = viewItems[index].parentItem;
    }
    removeViewItems(item + 1, total); // collapse
    q->setState(stateBeforeAnimation);
 
    if (emitSignal) {
        emit q->collapsed(modelIndex);
#if QT_CONFIG(animation)
        if (animationsEnabled)
            beginAnimatedOperation();
#endif // animation
    }
}
 
#if QT_CONFIG(animation)
void QTreeViewPrivate::prepareAnimatedOperation(int item, QVariantAnimation::Direction direction)
{
    animatedOperation.item = item;
    animatedOperation.viewport = viewport;
    animatedOperation.setDirection(direction);
 
    int top = coordinateForItem(item) + itemHeight(item);
    QRect rect = viewport->rect();
    rect.setTop(top);
    if (direction == QVariantAnimation::Backward) {
        const int limit = rect.height() * 2;
        int h = 0;
        int c = item + viewItems.at(item).total + 1;
        for (int i = item + 1; i < c && h < limit; ++i)
            h += itemHeight(i);
        rect.setHeight(h);
        animatedOperation.setEndValue(top + h);
    }
    animatedOperation.setStartValue(top);
    animatedOperation.before = renderTreeToPixmapForAnimation(rect);
}
 
void QTreeViewPrivate::beginAnimatedOperation()
{
    Q_Q(QTreeView);
 
    QRect rect = viewport->rect();
    rect.setTop(animatedOperation.top());
    if (animatedOperation.direction() == QVariantAnimation::Forward) {
        const int limit = rect.height() * 2;
        int h = 0;
        int c = animatedOperation.item + viewItems.at(animatedOperation.item).total + 1;
        for (int i = animatedOperation.item + 1; i < c && h < limit; ++i)
            h += itemHeight(i);
        rect.setHeight(h);
        animatedOperation.setEndValue(animatedOperation.top() + h);
    }
 
    if (!rect.isEmpty()) {
        animatedOperation.after = renderTreeToPixmapForAnimation(rect);
 
        q->setState(QAbstractItemView::AnimatingState);
        animatedOperation.start(); //let's start the animation
    }
}
 
void QTreeViewPrivate::drawAnimatedOperation(QPainter *painter) const
{
    const int start = animatedOperation.startValue().toInt(),
        end = animatedOperation.endValue().toInt(),
        current = animatedOperation.currentValue().toInt();
    bool collapsing = animatedOperation.direction() == QVariantAnimation::Backward;
    const QPixmap top = collapsing ? animatedOperation.before : animatedOperation.after;
    painter->drawPixmap(0, start, top, 0, end - current - 1, top.width(), top.height());
    const QPixmap bottom = collapsing ? animatedOperation.after : animatedOperation.before;
    painter->drawPixmap(0, current, bottom);
}
 
QPixmap QTreeViewPrivate::renderTreeToPixmapForAnimation(const QRect &rect) const
{
    Q_Q(const QTreeView);
    QPixmap pixmap(rect.size() * q->devicePixelRatio());
    pixmap.setDevicePixelRatio(q->devicePixelRatio());
    if (rect.size().isEmpty())
        return pixmap;
    pixmap.fill(Qt::transparent); //the base might not be opaque, and we don't want uninitialized pixels.
    QPainter painter(&pixmap);
    painter.fillRect(QRect(QPoint(0,0), rect.size()), q->palette().base());
    painter.translate(0, -rect.top());
    q->drawTree(&painter, QRegion(rect));
    painter.end();
 
    //and now let's render the editors the editors
    QStyleOptionViewItem option;
    q->initViewItemOption(&option);
    for (QEditorIndexHash::const_iterator it = editorIndexHash.constBegin(); it != editorIndexHash.constEnd(); ++it) {
        QWidget *editor = it.key();
        const QModelIndex &index = it.value();
        option.rect = visualRect(index, SingleSection);
        if (option.rect.isValid()) {
 
            if (QAbstractItemDelegate *delegate = q->itemDelegateForIndex(index))
                delegate->updateEditorGeometry(editor, option, index);
 
            const QPoint pos = editor->pos();
            if (rect.contains(pos)) {
                editor->render(&pixmap, pos - rect.topLeft());
                //the animation uses pixmap to display the treeview's content
                //the editor is rendered on this pixmap and thus can (should) be hidden
                editor->hide();
            }
        }
    }
 
 
    return pixmap;
}
 
void QTreeViewPrivate::endAnimatedOperation()
{
    Q_Q(QTreeView);
    q->setState(stateBeforeAnimation);
    q->updateGeometries();
    viewport->update();
}
#endif // animation
 
void QTreeViewPrivate::modelAboutToBeReset()
{
    viewItems.clear();
}
 
void QTreeViewPrivate::columnsAboutToBeRemoved(const QModelIndex &parent, int start, int end)
{
    if (start <= 0 && 0 <= end)
        viewItems.clear();
    QAbstractItemViewPrivate::columnsAboutToBeRemoved(parent, start, end);
}
 
void QTreeViewPrivate::columnsRemoved(const QModelIndex &parent, int start, int end)
{
    if (start <= 0 && 0 <= end)
        doDelayedItemsLayout();
    QAbstractItemViewPrivate::columnsRemoved(parent, start, end);
}
 
void QTreeViewPrivate::updateAccessibility()
{
#if QT_CONFIG(accessibility)
    Q_Q(QTreeView);
    if (pendingAccessibilityUpdate) {
        pendingAccessibilityUpdate = false;
        if (QAccessible::isActive()) {
            QAccessibleTableModelChangeEvent event(q, QAccessibleTableModelChangeEvent::ModelReset);
            QAccessible::updateAccessibility(&event);
        }
    }
#endif
}
 
 
void QTreeViewPrivate::layout(int i, bool recursiveExpanding, bool afterIsUninitialized)
{
    Q_Q(QTreeView);
    QModelIndex current;
    QModelIndex parent = (i < 0) ? (QModelIndex)root : modelIndex(i);
 
    if (i>=0 && !parent.isValid()) {
        //modelIndex() should never return something invalid for the real items.
        //This can happen if columncount has been set to 0.
        //To avoid infinite loop we stop here.
        return;
    }
 
#if QT_CONFIG(accessibility)
    // QAccessibleTree's rowCount implementation uses viewItems.size(), so
    // we need to invalidate any cached accessibility data structures if
    // that value changes during the run of this function.
    const auto resetModelIfNeeded = qScopeGuard([oldViewItemsSize = viewItems.size(), this]{
        pendingAccessibilityUpdate |= oldViewItemsSize != viewItems.size();
    });
#endif
 
    int count = 0;
    if (model->hasChildren(parent)) {
        if (model->canFetchMore(parent)) {
            // fetchMore first, otherwise we might not yet have any data for sizeHintForRow
            model->fetchMore(parent);
            // guestimate the number of items in the viewport, and fetch as many as might fit
            const int itemHeight = defaultItemHeight <= 0 ? q->sizeHintForRow(0) : defaultItemHeight;
            const int viewCount = itemHeight ? viewport->height() / itemHeight : 0;
            int lastCount = -1;
            while ((count = model->rowCount(parent)) < viewCount &&
                   count != lastCount && model->canFetchMore(parent)) {
                model->fetchMore(parent);
                lastCount = count;
            }
        } else {
            count = model->rowCount(parent);
        }
    }
 
    bool expanding = true;
    if (i == -1) {
        if (uniformRowHeights) {
            QModelIndex index = model->index(0, 0, parent);
            defaultItemHeight = q->indexRowSizeHint(index);
        }
        viewItems.resize(count);
        afterIsUninitialized = true;
    } else if (viewItems[i].total != (uint)count) {
        if (!afterIsUninitialized)
            insertViewItems(i + 1, count, QTreeViewItem()); // expand
        else if (count > 0)
            viewItems.resize(viewItems.size() + count);
    } else {
        expanding = false;
    }
 
    int first = i + 1;
    int level = (i >= 0 ? viewItems.at(i).level + 1 : 0);
    int hidden = 0;
    int last = 0;
    int children = 0;
    QTreeViewItem *item = nullptr;
    for (int j = first; j < first + count; ++j) {
        current = model->index(j - first, 0, parent);
        if (isRowHidden(current)) {
            ++hidden;
            last = j - hidden + children;
        } else {
            last = j - hidden + children;
            if (item)
                item->hasMoreSiblings = true;
            item = &viewItems[last];
            item->index = current;
            item->parentItem = i;
            item->level = level;
            item->height = 0;
            item->spanning = q->isFirstColumnSpanned(current.row(), parent);
            item->expanded = false;
            item->total = 0;
            item->hasMoreSiblings = false;
            if ((recursiveExpanding && !(current.flags() & Qt::ItemNeverHasChildren)) || isIndexExpanded(current)) {
                if (recursiveExpanding && storeExpanded(current) && !q->signalsBlocked())
                    emit q->expanded(current);
                item->expanded = true;
                layout(last, recursiveExpanding, afterIsUninitialized);
                item = &viewItems[last];
                children += item->total;
                item->hasChildren = item->total > 0;
                last = j - hidden + children;
            } else {
                item->hasChildren = hasVisibleChildren(current);
            }
        }
    }
 
    // remove hidden items
    if (hidden > 0) {
        if (!afterIsUninitialized)
            removeViewItems(last + 1, hidden);
        else
            viewItems.resize(viewItems.size() - hidden);
    }
 
    if (!expanding)
        return; // nothing changed
 
    while (i > -1) {
        viewItems[i].total += count - hidden;
        i = viewItems[i].parentItem;
    }
}
 
int QTreeViewPrivate::pageUp(int i) const
{
    int index = itemAtCoordinate(coordinateForItem(i) - viewport->height());
    while (isItemHiddenOrDisabled(index))
        index--;
    if (index == -1)
        index = 0;
    while (isItemHiddenOrDisabled(index))
        index++;
    return index >= viewItems.size() ? 0 : index;
}
 
int QTreeViewPrivate::pageDown(int i) const
{
    int index = itemAtCoordinate(coordinateForItem(i) + viewport->height());
    while (isItemHiddenOrDisabled(index))
        index++;
    if (index == -1 || index >= viewItems.size())
        index = viewItems.size() - 1;
    while (isItemHiddenOrDisabled(index))
        index--;
    return index == -1 ? viewItems.size() - 1 : index;
}
 
int QTreeViewPrivate::itemForKeyHome() const
{
    int index = 0;
    while (isItemHiddenOrDisabled(index))
        index++;
    return index >= viewItems.size() ? 0 : index;
}
 
int QTreeViewPrivate::itemForKeyEnd() const
{
    int index = viewItems.size() - 1;
    while (isItemHiddenOrDisabled(index))
        index--;
    return index == -1 ? viewItems.size() - 1 : index;
}
 
int QTreeViewPrivate::indentationForItem(int item) const
{
    if (item < 0 || item >= viewItems.size())
        return 0;
    int level = viewItems.at(item).level;
    if (rootDecoration)
        ++level;
    return level * indent;
}
 
int QTreeViewPrivate::itemHeight(int item) const
{
    Q_ASSERT(item < viewItems.size());
    if (uniformRowHeights)
        return defaultItemHeight;
    if (viewItems.isEmpty())
        return 0;
    const QModelIndex &index = viewItems.at(item).index;
    if (!index.isValid())
        return 0;
    int height = viewItems.at(item).height;
    if (height <= 0) {
        height = q_func()->indexRowSizeHint(index);
        viewItems[item].height = height;
    }
    return qMax(height, 0);
}
 
 
int QTreeViewPrivate::coordinateForItem(int item) const
{
    if (verticalScrollMode == QAbstractItemView::ScrollPerPixel) {
        if (uniformRowHeights)
            return (item * defaultItemHeight) - vbar->value();
        // ### optimize (maybe do like QHeaderView by letting items have startposition)
        int y = 0;
        for (int i = 0; i < viewItems.size(); ++i) {
            if (i == item)
                return y - vbar->value();
            y += itemHeight(i);
        }
    } else { // ScrollPerItem
        int topViewItemIndex = vbar->value();
        if (uniformRowHeights)
            return defaultItemHeight * (item - topViewItemIndex);
        if (item >= topViewItemIndex) {
            // search in the visible area first and continue down
            // ### slow if the item is not visible
            int viewItemCoordinate = 0;
            int viewItemIndex = topViewItemIndex;
            while (viewItemIndex < viewItems.size()) {
                if (viewItemIndex == item)
                    return viewItemCoordinate;
                viewItemCoordinate += itemHeight(viewItemIndex);
                ++viewItemIndex;
            }
            // below the last item in the view
            Q_ASSERT(false);
            return viewItemCoordinate;
        } else {
            // search the area above the viewport (used for editor widgets)
            int viewItemCoordinate = 0;
            for (int viewItemIndex = topViewItemIndex; viewItemIndex > 0; --viewItemIndex) {
                if (viewItemIndex == item)
                    return viewItemCoordinate;
                viewItemCoordinate -= itemHeight(viewItemIndex - 1);
            }
            return viewItemCoordinate;
        }
    }
    return 0;
}
 
int QTreeViewPrivate::itemAtCoordinate(int coordinate) const
{
    const int itemCount = viewItems.size();
    if (itemCount == 0)
        return -1;
    if (uniformRowHeights && defaultItemHeight <= 0)
        return -1;
    if (verticalScrollMode == QAbstractItemView::ScrollPerPixel) {
        if (uniformRowHeights) {
            const int viewItemIndex = (coordinate + vbar->value()) / defaultItemHeight;
            return ((viewItemIndex >= itemCount || viewItemIndex < 0) ? -1 : viewItemIndex);
        }
        // ### optimize
        int viewItemCoordinate = 0;
        const int contentsCoordinate = coordinate + vbar->value();
        for (int viewItemIndex = 0; viewItemIndex < viewItems.size(); ++viewItemIndex) {
            viewItemCoordinate += itemHeight(viewItemIndex);
            if (viewItemCoordinate > contentsCoordinate)
                return (viewItemIndex >= itemCount ? -1 : viewItemIndex);
        }
    } else { // ScrollPerItem
        int topViewItemIndex = vbar->value();
        if (uniformRowHeights) {
            if (coordinate < 0)
                coordinate -= defaultItemHeight - 1;
            const int viewItemIndex = topViewItemIndex + (coordinate / defaultItemHeight);
            return ((viewItemIndex >= itemCount || viewItemIndex < 0) ? -1 : viewItemIndex);
        }
        if (coordinate >= 0) {
            // the coordinate is in or below the viewport
            int viewItemCoordinate = 0;
            for (int viewItemIndex = topViewItemIndex; viewItemIndex < viewItems.size(); ++viewItemIndex) {
                viewItemCoordinate += itemHeight(viewItemIndex);
                if (viewItemCoordinate > coordinate)
                    return (viewItemIndex >= itemCount ? -1 : viewItemIndex);
            }
        } else {
            // the coordinate is above the viewport
            int viewItemCoordinate = 0;
            for (int viewItemIndex = topViewItemIndex; viewItemIndex >= 0; --viewItemIndex) {
                if (viewItemCoordinate <= coordinate)
                    return (viewItemIndex >= itemCount ? -1 : viewItemIndex);
                viewItemCoordinate -= itemHeight(viewItemIndex);
            }
        }
    }
    return -1;
}
 
int QTreeViewPrivate::viewIndex(const QModelIndex &_index) const
{
    if (!_index.isValid() || viewItems.isEmpty())
        return -1;
 
    const int totalCount = viewItems.size();
    const QModelIndex index = _index.sibling(_index.row(), 0);
    const int row = index.row();
    const quintptr internalId = index.internalId();
 
    // We start nearest to the lastViewedItem
    int localCount = qMin(lastViewedItem - 1, totalCount - lastViewedItem);
    for (int i = 0; i < localCount; ++i) {
        const QModelIndex &idx1 = viewItems.at(lastViewedItem + i).index;
        if (idx1.row() == row && idx1.internalId() == internalId) {
            lastViewedItem = lastViewedItem + i;
            return lastViewedItem;
        }
        const QModelIndex &idx2 = viewItems.at(lastViewedItem - i - 1).index;
        if (idx2.row() == row && idx2.internalId() == internalId) {
            lastViewedItem = lastViewedItem - i - 1;
            return lastViewedItem;
        }
    }
 
    for (int j = qMax(0, lastViewedItem + localCount); j < totalCount; ++j) {
        const QModelIndex &idx = viewItems.at(j).index;
        if (idx.row() == row && idx.internalId() == internalId) {
            lastViewedItem = j;
            return j;
        }
    }
    for (int j = qMin(totalCount, lastViewedItem - localCount) - 1; j >= 0; --j) {
        const QModelIndex &idx = viewItems.at(j).index;
        if (idx.row() == row && idx.internalId() == internalId) {
            lastViewedItem = j;
            return j;
        }
    }
 
    // nothing found
    return -1;
}
 
QModelIndex QTreeViewPrivate::modelIndex(int i, int column) const
{
    if (i < 0 || i >= viewItems.size())
        return QModelIndex();
 
    QModelIndex ret = viewItems.at(i).index;
    if (column)
        ret = ret.sibling(ret.row(), column);
    return ret;
}
 
int QTreeViewPrivate::firstVisibleItem(int *offset) const
{
    const int value = vbar->value();
    if (verticalScrollMode == QAbstractItemView::ScrollPerItem) {
        if (offset)
            *offset = 0;
        return (value < 0 || value >= viewItems.size()) ? -1 : value;
    }
    // ScrollMode == ScrollPerPixel
    if (uniformRowHeights) {
        if (!defaultItemHeight)
            return -1;
 
        if (offset)
            *offset = -(value % defaultItemHeight);
        return value / defaultItemHeight;
    }
    int y = 0; // ### (maybe do like QHeaderView by letting items have startposition)
    for (int i = 0; i < viewItems.size(); ++i) {
        y += itemHeight(i); // the height value is cached
        if (y > value) {
            if (offset)
                *offset = y - value - itemHeight(i);
            return i;
        }
    }
    return -1;
}
 
int QTreeViewPrivate::lastVisibleItem(int firstVisual, int offset) const
{
    if (firstVisual < 0 || offset < 0) {
        firstVisual = firstVisibleItem(&offset);
        if (firstVisual < 0)
            return -1;
    }
    int y = - offset;
    int value = viewport->height();
 
    for (int i = firstVisual; i < viewItems.size(); ++i) {
        y += itemHeight(i); // the height value is cached
        if (y > value)
            return i;
    }
    return viewItems.size() - 1;
}
 
int QTreeViewPrivate::columnAt(int x) const
{
    return header->logicalIndexAt(x);
}
 
void QTreeViewPrivate::updateScrollBars()
{
    Q_Q(QTreeView);
    QSize viewportSize = viewport->size();
    if (!viewportSize.isValid())
        viewportSize = QSize(0, 0);
 
    executePostedLayout();
    if (viewItems.isEmpty()) {
        q->doItemsLayout();
    }
 
    int itemsInViewport = 0;
    if (uniformRowHeights) {
        if (defaultItemHeight <= 0)
            itemsInViewport = viewItems.size();
        else
            itemsInViewport = viewportSize.height() / defaultItemHeight;
    } else {
        const int itemsCount = viewItems.size();
        const int viewportHeight = viewportSize.height();
        for (int height = 0, item = itemsCount - 1; item >= 0; --item) {
            height += itemHeight(item);
            if (height > viewportHeight)
                break;
            ++itemsInViewport;
        }
    }
    if (verticalScrollMode == QAbstractItemView::ScrollPerItem) {
        if (!viewItems.isEmpty())
            itemsInViewport = qMax(1, itemsInViewport);
        vbar->setRange(0, viewItems.size() - itemsInViewport);
        vbar->setPageStep(itemsInViewport);
        vbar->setSingleStep(1);
    } else { // scroll per pixel
        int contentsHeight = 0;
        if (uniformRowHeights) {
            contentsHeight = defaultItemHeight * viewItems.size();
        } else { // ### (maybe do like QHeaderView by letting items have startposition)
            for (int i = 0; i < viewItems.size(); ++i)
                contentsHeight += itemHeight(i);
        }
        vbar->setRange(0, contentsHeight - viewportSize.height());
        vbar->setPageStep(viewportSize.height());
        vbar->d_func()->itemviewChangeSingleStep(qMax(viewportSize.height() / (itemsInViewport + 1), 2));
    }
 
    const int columnCount = header->count();
    const int viewportWidth = viewportSize.width();
    int columnsInViewport = 0;
    for (int width = 0, column = columnCount - 1; column >= 0; --column) {
        int logical = header->logicalIndex(column);
        width += header->sectionSize(logical);
        if (width > viewportWidth)
            break;
        ++columnsInViewport;
    }
    if (columnCount > 0)
        columnsInViewport = qMax(1, columnsInViewport);
    if (horizontalScrollMode == QAbstractItemView::ScrollPerItem) {
        hbar->setRange(0, columnCount - columnsInViewport);
        hbar->setPageStep(columnsInViewport);
        hbar->setSingleStep(1);
    } else { // scroll per pixel
        const int horizontalLength = header->length();
        const QSize maxSize = q->maximumViewportSize();
        if (maxSize.width() >= horizontalLength && vbar->maximum() <= 0)
            viewportSize = maxSize;
        hbar->setPageStep(viewportSize.width());
        hbar->setRange(0, qMax(horizontalLength - viewportSize.width(), 0));
        hbar->d_func()->itemviewChangeSingleStep(qMax(viewportSize.width() / (columnsInViewport + 1), 2));
    }
}
 
int QTreeViewPrivate::itemDecorationAt(const QPoint &pos) const
{
    Q_Q(const QTreeView);
    executePostedLayout();
    bool spanned = false;
    if (!spanningIndexes.isEmpty()) {
        const QModelIndex index = q->indexAt(pos);
        if (index.isValid())
            spanned = q->isFirstColumnSpanned(index.row(), index.parent());
    }
    const int column = spanned ? 0 : header->logicalIndexAt(pos.x());
    if (!isTreePosition(column))
        return -1; // no logical index at x
 
    int viewItemIndex = itemAtCoordinate(pos.y());
    QRect returning = itemDecorationRect(modelIndex(viewItemIndex));
    if (!returning.contains(pos))
        return -1;
 
    return viewItemIndex;
}
 
QRect QTreeViewPrivate::itemDecorationRect(const QModelIndex &index) const
{
    Q_Q(const QTreeView);
    if (!rootDecoration && index.parent() == root)
        return QRect(); // no decoration at root
 
    int viewItemIndex = viewIndex(index);
    if (viewItemIndex < 0 || !hasVisibleChildren(viewItems.at(viewItemIndex).index))
        return QRect();
 
    int itemIndentation = indentationForItem(viewItemIndex);
    int position = header->sectionViewportPosition(logicalIndexForTree());
    int size = header->sectionSize(logicalIndexForTree());
 
    QRect rect;
    if (q->isRightToLeft())
        rect = QRect(position + size - itemIndentation, coordinateForItem(viewItemIndex),
                     indent, itemHeight(viewItemIndex));
    else
        rect = QRect(position + itemIndentation - indent, coordinateForItem(viewItemIndex),
                     indent, itemHeight(viewItemIndex));
    QStyleOption opt;
    opt.initFrom(q);
    opt.rect = rect;
    return q->style()->subElementRect(QStyle::SE_TreeViewDisclosureItem, &opt, q);
}
 
QList<QPair<int, int>> QTreeViewPrivate::columnRanges(const QModelIndex &topIndex,
                                                      const QModelIndex &bottomIndex) const
{
    const int topVisual = header->visualIndex(topIndex.column()),
        bottomVisual = header->visualIndex(bottomIndex.column());
 
    const int start = qMin(topVisual, bottomVisual);
    const int end = qMax(topVisual, bottomVisual);
 
    QList<int> logicalIndexes;
 
    //we iterate over the visual indexes to get the logical indexes
    for (int c = start; c <= end; c++) {
        const int logical = header->logicalIndex(c);
        if (!header->isSectionHidden(logical)) {
            logicalIndexes << logical;
        }
    }
    //let's sort the list
    std::sort(logicalIndexes.begin(), logicalIndexes.end());
 
    QList<QPair<int, int>> ret;
    QPair<int, int> current;
    current.first = -2; // -1 is not enough because -1+1 = 0
    current.second = -2;
    for(int i = 0; i < logicalIndexes.size(); ++i) {
        const int logicalColumn = logicalIndexes.at(i);
        if (current.second + 1 != logicalColumn) {
            if (current.first != -2) {
                //let's save the current one
                ret += current;
            }
            //let's start a new one
            current.first = current.second = logicalColumn;
        } else {
            current.second++;
        }
    }
 
    //let's get the last range
    if (current.first != -2) {
        ret += current;
    }
 
    return ret;
}
 
void QTreeViewPrivate::select(const QModelIndex &topIndex, const QModelIndex &bottomIndex,
                              QItemSelectionModel::SelectionFlags command)
{
    Q_Q(QTreeView);
    QItemSelection selection;
    const int top = viewIndex(topIndex),
        bottom = viewIndex(bottomIndex);
 
    const QList<QPair<int, int>> colRanges = columnRanges(topIndex, bottomIndex);
    QList<QPair<int, int>>::const_iterator it;
    for (it = colRanges.begin(); it != colRanges.end(); ++it) {
        const int left = (*it).first,
            right = (*it).second;
 
        QModelIndex previous;
        QItemSelectionRange currentRange;
        QStack<QItemSelectionRange> rangeStack;
        for (int i = top; i <= bottom; ++i) {
            QModelIndex index = modelIndex(i);
            QModelIndex parent = index.parent();
            QModelIndex previousParent = previous.parent();
            if (previous.isValid() && parent == previousParent) {
                // same parent
                if (qAbs(previous.row() - index.row()) > 1) {
                    //a hole (hidden index inside a range) has been detected
                    if (currentRange.isValid()) {
                        selection.append(currentRange);
                    }
                    //let's start a new range
                    currentRange = QItemSelectionRange(index.sibling(index.row(), left), index.sibling(index.row(), right));
                } else {
                    QModelIndex tl = model->index(currentRange.top(), currentRange.left(),
                        currentRange.parent());
                    currentRange = QItemSelectionRange(tl, index.sibling(index.row(), right));
                }
            } else if (previous.isValid() && parent == model->index(previous.row(), 0, previousParent)) {
                // item is child of previous
                rangeStack.push(currentRange);
                currentRange = QItemSelectionRange(index.sibling(index.row(), left), index.sibling(index.row(), right));
            } else {
                if (currentRange.isValid())
                    selection.append(currentRange);
                if (rangeStack.isEmpty()) {
                    currentRange = QItemSelectionRange(index.sibling(index.row(), left), index.sibling(index.row(), right));
                } else {
                    currentRange = rangeStack.pop();
                    index = currentRange.bottomRight(); //let's resume the range
                    --i; //we process again the current item
                }
            }
            previous = index;
        }
        if (currentRange.isValid())
            selection.append(currentRange);
        for (int i = 0; i < rangeStack.size(); ++i)
            selection.append(rangeStack.at(i));
    }
    q->selectionModel()->select(selection, command);
}
 
QPair<int,int> QTreeViewPrivate::startAndEndColumns(const QRect &rect) const
{
    Q_Q(const QTreeView);
    int start = header->visualIndexAt(rect.left());
    int end = header->visualIndexAt(rect.right());
    if (q->isRightToLeft()) {
        start = (start == -1 ? header->count() - 1 : start);
        end = (end == -1 ? 0 : end);
    } else {
        start = (start == -1 ? 0 : start);
        end = (end == -1 ? header->count() - 1 : end);
    }
    return qMakePair(qMin(start, end), qMax(start, end));
}
 
bool QTreeViewPrivate::hasVisibleChildren(const QModelIndex& parent) const
{
    Q_Q(const QTreeView);
    if (parent.flags() & Qt::ItemNeverHasChildren)
        return false;
    if (model->hasChildren(parent)) {
        if (hiddenIndexes.isEmpty())
            return true;
        if (q->isIndexHidden(parent))
            return false;
        int rowCount = model->rowCount(parent);
        for (int i = 0; i < rowCount; ++i) {
            if (!q->isRowHidden(i, parent))
                return true;
        }
        if (rowCount == 0)
            return true;
    }
    return false;
}
 
void QTreeViewPrivate::sortIndicatorChanged(int column, Qt::SortOrder order)
{
    model->sort(column, order);
}
 
int QTreeViewPrivate::accessibleTree2Index(const QModelIndex &index) const
{
    Q_Q(const QTreeView);
 
    // Note that this will include the header, even if its hidden.
    return (q->visualIndex(index) + (q->header() ? 1 : 0)) * index.model()->columnCount() + index.column();
}
 
void QTreeViewPrivate::updateIndentationFromStyle()
{
    Q_Q(const QTreeView);
    indent = q->style()->pixelMetric(QStyle::PM_TreeViewIndentation, nullptr, q);
}
 
void QTreeView::currentChanged(const QModelIndex &current, const QModelIndex &previous)
{
    Q_D(QTreeView);
    QAbstractItemView::currentChanged(current, previous);
 
    if (allColumnsShowFocus()) {
        if (previous.isValid())
            viewport()->update(d->visualRect(previous, QTreeViewPrivate::FullRow));
        if (current.isValid())
            viewport()->update(d->visualRect(current, QTreeViewPrivate::FullRow));
    }
#if QT_CONFIG(accessibility)
    if (QAccessible::isActive() && current.isValid() && hasFocus()) {
        Q_D(QTreeView);
 
        QAccessibleEvent event(this, QAccessible::Focus);
        event.setChild(d->accessibleTree2Index(current));
        QAccessible::updateAccessibility(&event);
    }
#endif
}
 
void QTreeView::selectionChanged(const QItemSelection &selected,
                                 const QItemSelection &deselected)
{
    QAbstractItemView::selectionChanged(selected, deselected);
#if QT_CONFIG(accessibility)
    if (QAccessible::isActive()) {
        Q_D(QTreeView);
 
        // ### does not work properly for selection ranges.
        QModelIndex sel = selected.indexes().value(0);
        if (sel.isValid()) {
            int entry = d->accessibleTree2Index(sel);
            Q_ASSERT(entry >= 0);
            QAccessibleEvent event(this, QAccessible::SelectionAdd);
            event.setChild(entry);
            QAccessible::updateAccessibility(&event);
        }
        QModelIndex desel = deselected.indexes().value(0);
        if (desel.isValid()) {
            int entry = d->accessibleTree2Index(desel);
            Q_ASSERT(entry >= 0);
            QAccessibleEvent event(this, QAccessible::SelectionRemove);
            event.setChild(entry);
            QAccessible::updateAccessibility(&event);
        }
    }
#endif
}
 
int QTreeView::visualIndex(const QModelIndex &index) const
{
    Q_D(const QTreeView);
    d->executePostedLayout();
    return d->viewIndex(index);
}
 
void QTreeView::verticalScrollbarValueChanged(int value)
{
    Q_D(QTreeView);
    if (!d->viewItems.isEmpty() && value == verticalScrollBar()->maximum()) {
        QModelIndex ret = d->viewItems.last().index;
        // Root index will be handled by base class implementation
        while (ret.isValid()) {
            if (isExpanded(ret) && d->model->canFetchMore(ret)) {
                d->model->fetchMore(ret);
                break;
            }
            ret = ret.parent();
        }
    }
    QAbstractItemView::verticalScrollbarValueChanged(value);
}
 
QT_END_NAMESPACE
 
#include "moc_qtreeview.cpp"