qitemselectionmodel.cpp

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#include "qitemselectionmodel.h"
#include <private/qitemselectionmodel_p.h>
#include <qdebug.h>

#ifndef QT_NO_ITEMVIEWS

QT_BEGIN_NAMESPACE

bool QItemSelectionRange::intersects(const QItemSelectionRange &other) const
{
    return (isValid() && other.isValid()
            && parent() == other.parent()
            && model() == other.model()
            && ((top() <= other.top() && bottom() >= other.top())
                || (top() >= other.top() && top() <= other.bottom()))
            && ((left() <= other.left() && right() >= other.left())
                || (left() >= other.left() && left() <= other.right())));
}

QItemSelectionRange QItemSelectionRange::intersect(const QItemSelectionRange &other) const
{
    if (model() == other.model() && parent() == other.parent()) {
        QModelIndex topLeft = model()->index(qMax(top(), other.top()),
                                             qMax(left(), other.left()),
                                             other.parent());
        QModelIndex bottomRight = model()->index(qMin(bottom(), other.bottom()),
                                                 qMin(right(), other.right()),
                                                 other.parent());
        return QItemSelectionRange(topLeft, bottomRight);
    }
    return QItemSelectionRange();
}

/*
  \internal

  utility function for getting the indexes from a range
  it avoid concatenating list and works on one
 */

static void indexesFromRange(const QItemSelectionRange &range, QModelIndexList &result)
{
    if (range.isValid() && range.model()) {
        for (int column = range.left(); column <= range.right(); ++column) {
            for (int row = range.top(); row <= range.bottom(); ++row) {
                QModelIndex index = range.model()->index(row, column, range.parent());
                Qt::ItemFlags flags = range.model()->flags(index);
                if ((flags & Qt::ItemIsSelectable) && (flags & Qt::ItemIsEnabled))
                    result.append(index);
            }
        }
    }
}

bool QItemSelectionRange::isEmpty() const
{
    if (!isValid() || !model())
        return true;

    for (int column = left(); column <= right(); ++column) {
        for (int row = top(); row <= bottom(); ++row) {
            QModelIndex index = model()->index(row, column, parent());
            Qt::ItemFlags flags = model()->flags(index);
            if ((flags & Qt::ItemIsSelectable) && (flags & Qt::ItemIsEnabled))
                return false;
        }
    }
    return true;
}

QModelIndexList QItemSelectionRange::indexes() const
{
    QModelIndexList result;
    indexesFromRange(*this, result);
    return result;
}

QItemSelection::QItemSelection(const QModelIndex &topLeft, const QModelIndex &bottomRight)
{
    select(topLeft, bottomRight);
}

void QItemSelection::select(const QModelIndex &topLeft, const QModelIndex &bottomRight)
{
    if (!topLeft.isValid() || !bottomRight.isValid())
        return;

    if ((topLeft.model() != bottomRight.model())
        || topLeft.parent() != bottomRight.parent()) {
        qWarning("Can't select indexes from different model or with different parents");
        return;
    }
    if (topLeft.row() > bottomRight.row() || topLeft.column() > bottomRight.column()) {
        int top = qMin(topLeft.row(), bottomRight.row());
        int bottom = qMax(topLeft.row(), bottomRight.row());
        int left = qMin(topLeft.column(), bottomRight.column());
        int right = qMax(topLeft.column(), bottomRight.column());
        QModelIndex tl = topLeft.sibling(top, left);
        QModelIndex br = bottomRight.sibling(bottom, right);
        append(QItemSelectionRange(tl, br));
        return;
    }
    append(QItemSelectionRange(topLeft, bottomRight));
}

bool QItemSelection::contains(const QModelIndex &index) const
{
    if (index.flags() & Qt::ItemIsSelectable) {
        QList<QItemSelectionRange>::const_iterator it = begin();
        for (; it != end(); ++it)
            if ((*it).contains(index))
                return true;
    }
    return false;
}

QModelIndexList QItemSelection::indexes() const
{
    QModelIndexList result;
    QList<QItemSelectionRange>::const_iterator it = begin();
    for (; it != end(); ++it)
        indexesFromRange(*it, result);
    return result;
}

void QItemSelection::merge(const QItemSelection &other, QItemSelectionModel::SelectionFlags command)
{
    if (other.isEmpty() ||
          !(command & QItemSelectionModel::Select ||
          command & QItemSelectionModel::Deselect ||
          command & QItemSelectionModel::Toggle))
        return;

    QItemSelection newSelection = other;
    // Collect intersections
    QItemSelection intersections;
    QItemSelection::iterator it = newSelection.begin();
    while (it != newSelection.end()) {
        if (!(*it).isValid()) {
            it = newSelection.erase(it);
            continue;
        }
        for (int t = 0; t < count(); ++t) {
            if ((*it).intersects(at(t)))
                intersections.append(at(t).intersected(*it));
        }
        ++it;
    }

    //  Split the old (and new) ranges using the intersections
    for (int i = 0; i < intersections.count(); ++i) { // for each intersection
        for (int t = 0; t < count();) { // splitt each old range
            if (at(t).intersects(intersections.at(i))) {
                split(at(t), intersections.at(i), this);
                removeAt(t);
            } else {
                ++t;
            }
        }
        // only split newSelection if Toggle is specified
        for (int n = 0; (command & QItemSelectionModel::Toggle) && n < newSelection.count();) {
            if (newSelection.at(n).intersects(intersections.at(i))) {
                split(newSelection.at(n), intersections.at(i), &newSelection);
                newSelection.removeAt(n);
            } else {
                ++n;
            }
        }
    }
    // do not add newSelection for Deselect
    if (!(command & QItemSelectionModel::Deselect))
        operator+=(newSelection);
}

void QItemSelection::split(const QItemSelectionRange &range,
                           const QItemSelectionRange &other, QItemSelection *result)
{
    if (range.parent() != other.parent() || range.model() != other.model())
        return;

    QModelIndex parent = other.parent();
    int top = range.top();
    int left = range.left();
    int bottom = range.bottom();
    int right = range.right();
    int other_top = other.top();
    int other_left = other.left();
    int other_bottom = other.bottom();
    int other_right = other.right();
    const QAbstractItemModel *model = range.model();
    Q_ASSERT(model);
    if (other_top > top) {
        QModelIndex tl = model->index(top, left, parent);
        QModelIndex br = model->index(other_top - 1, right, parent);
        result->append(QItemSelectionRange(tl, br));
        top = other_top;
    }
    if (other_bottom < bottom) {
        QModelIndex tl = model->index(other_bottom + 1, left, parent);
        QModelIndex br = model->index(bottom, right, parent);
        result->append(QItemSelectionRange(tl, br));
        bottom = other_bottom;
    }
    if (other_left > left) {
        QModelIndex tl = model->index(top, left, parent);
        QModelIndex br = model->index(bottom, other_left - 1, parent);
        result->append(QItemSelectionRange(tl, br));
        left = other_left;
    }
    if (other_right < right) {
        QModelIndex tl = model->index(top, other_right + 1, parent);
        QModelIndex br = model->index(bottom, right, parent);
        result->append(QItemSelectionRange(tl, br));
        right = other_right;
    }
}


void QItemSelectionModelPrivate::initModel(QAbstractItemModel *model)
{
    this->model = model;
    if (model) {
        Q_Q(QItemSelectionModel);
        QObject::connect(model, SIGNAL(rowsAboutToBeRemoved(QModelIndex,int,int)),
                q, SLOT(_q_rowsAboutToBeRemoved(QModelIndex,int,int)));
        QObject::connect(model, SIGNAL(columnsAboutToBeRemoved(QModelIndex,int,int)),
                q, SLOT(_q_columnsAboutToBeRemoved(QModelIndex,int,int)));
        QObject::connect(model, SIGNAL(rowsAboutToBeInserted(QModelIndex,int,int)),
                q, SLOT(_q_rowsAboutToBeInserted(QModelIndex,int,int)));
        QObject::connect(model, SIGNAL(columnsAboutToBeInserted(QModelIndex,int,int)),
                q, SLOT(_q_columnsAboutToBeInserted(QModelIndex,int,int)));
        QObject::connect(model, SIGNAL(layoutAboutToBeChanged()),
                q, SLOT(_q_layoutAboutToBeChanged()));
        QObject::connect(model, SIGNAL(layoutChanged()),
                q, SLOT(_q_layoutChanged()));
    }
}

QItemSelection QItemSelectionModelPrivate::expandSelection(const QItemSelection &selection,
                                                           QItemSelectionModel::SelectionFlags command) const
{
    if (selection.isEmpty() && !((command & QItemSelectionModel::Rows) ||
                                 (command & QItemSelectionModel::Columns)))
        return selection;

    QItemSelection expanded;
    if (command & QItemSelectionModel::Rows) {
        for (int i = 0; i < selection.count(); ++i) {
            QModelIndex parent = selection.at(i).parent();
            int colCount = model->columnCount(parent);
            QModelIndex tl = model->index(selection.at(i).top(), 0, parent);
            QModelIndex br = model->index(selection.at(i).bottom(), colCount - 1, parent);
            //we need to merge because the same row could have already been inserted
            expanded.merge(QItemSelection(tl, br), QItemSelectionModel::Select);
        }
    }
    if (command & QItemSelectionModel::Columns) {
        for (int i = 0; i < selection.count(); ++i) {
            QModelIndex parent = selection.at(i).parent();
            int rowCount = model->rowCount(parent);
            QModelIndex tl = model->index(0, selection.at(i).left(), parent);
            QModelIndex br = model->index(rowCount - 1, selection.at(i).right(), parent);
            //we need to merge because the same column could have already been inserted
            expanded.merge(QItemSelection(tl, br), QItemSelectionModel::Select);
        }
    }
    return expanded;
}

void QItemSelectionModelPrivate::_q_rowsAboutToBeRemoved(const QModelIndex &parent,
                                                         int start, int end)
{
    Q_Q(QItemSelectionModel);
    finalize();

    // update current index
    if (currentIndex.isValid() && parent == currentIndex.parent()
        && currentIndex.row() >= start && currentIndex.row() <= end) {
        QModelIndex old = currentIndex;
        if (start > 0) // there are rows left above the change
            currentIndex = model->index(start - 1, old.column(), parent);
        else if (model && end < model->rowCount(parent) - 1) // there are rows left below the change
            currentIndex = model->index(end + 1, old.column(), parent);
        else // there are no rows left in the table
            currentIndex = QModelIndex();
        emit q->currentChanged(currentIndex, old);
        emit q->currentRowChanged(currentIndex, old);
        if (currentIndex.column() != old.column())
            emit q->currentColumnChanged(currentIndex, old);
    }

    QItemSelection deselected;
    QItemSelection newParts;
    QItemSelection::iterator it = ranges.begin();
    while (it != ranges.end()) {
        if (it->topLeft().parent() != parent) {  // Check parents until reaching root or contained in range
            QModelIndex itParent = it->topLeft().parent();
            while (itParent.isValid() && itParent.parent() != parent)
                itParent = itParent.parent();

            if (itParent.isValid() && start <= itParent.row() && itParent.row() <= end) {
                deselected.append(*it);
                it = ranges.erase(it);
            } else {
                ++it;
            }
        } else if (start <= it->bottom() && it->bottom() <= end    // Full inclusion
                   && start <= it->top() && it->top() <= end) {
            deselected.append(*it);
            it = ranges.erase(it);
        } else if (start <= it->top() && it->top() <= end) {      // Top intersection
            deselected.append(QItemSelectionRange(it->topLeft(), model->index(end, it->left(), it->parent())));
            *it = QItemSelectionRange(model->index(end + 1, it->left(), it->parent()), it->bottomRight());
            ++it;
        } else if (start <= it->bottom() && it->bottom() <= end) {    // Bottom intersection
            deselected.append(QItemSelectionRange(model->index(start, it->right(), it->parent()), it->bottomRight()));
            *it = QItemSelectionRange(it->topLeft(), model->index(start - 1, it->right(), it->parent()));
            ++it;
        } else if (it->top() < start && end < it->bottom()) { // Middle intersection
            // If the parent contains (1, 2, 3, 4, 5, 6, 7, 8) and [3, 4, 5, 6] is selected,
            // and [4, 5] is removed, we need to split [3, 4, 5, 6] into [3], [4, 5] and [6].
            // [4, 5] is appended to deselected, and [3] and [6] remain part of the selection
            // in ranges.
            const QItemSelectionRange removedRange(model->index(start, it->right(), it->parent()),
                                                    model->index(end, it->left(), it->parent()));
            deselected.append(removedRange);
            QItemSelection::split(*it, removedRange, &newParts);
            it = ranges.erase(it);
        } else
            ++it;
    }
    ranges.append(newParts);

    if (!deselected.isEmpty())
        emit q->selectionChanged(QItemSelection(), deselected);
}

void QItemSelectionModelPrivate::_q_columnsAboutToBeRemoved(const QModelIndex &parent,
                                                            int start, int end)
{
    Q_Q(QItemSelectionModel);

    // update current index
    if (currentIndex.isValid() && parent == currentIndex.parent()
        && currentIndex.column() >= start && currentIndex.column() <= end) {
        QModelIndex old = currentIndex;
        if (start > 0) // there are columns to the left of the change
            currentIndex = model->index(old.row(), start - 1, parent);
        else if (model && end < model->columnCount() - 1) // there are columns to the right of the change
            currentIndex = model->index(old.row(), end + 1, parent);
        else // there are no columns left in the table
            currentIndex = QModelIndex();
        emit q->currentChanged(currentIndex, old);
        if (currentIndex.row() != old.row())
            emit q->currentRowChanged(currentIndex, old);
        emit q->currentColumnChanged(currentIndex, old);
    }

    // update selections
    QModelIndex tl = model->index(0, start, parent);
    QModelIndex br = model->index(model->rowCount(parent) - 1, end, parent);
    q->select(QItemSelection(tl, br), QItemSelectionModel::Deselect);
    finalize();
}

void QItemSelectionModelPrivate::_q_columnsAboutToBeInserted(const QModelIndex &parent,
                                                             int start, int end)
{
    Q_UNUSED(end);
    finalize();
    QList<QItemSelectionRange> split;
    QList<QItemSelectionRange>::iterator it = ranges.begin();
    for (; it != ranges.end(); ) {
        if ((*it).isValid() && (*it).parent() == parent
            && (*it).left() < start && (*it).right() >= start) {
            QModelIndex bottomMiddle = model->index((*it).bottom(), start - 1, (*it).parent());
            QItemSelectionRange left((*it).topLeft(), bottomMiddle);
            QModelIndex topMiddle = model->index((*it).top(), start, (*it).parent());
            QItemSelectionRange right(topMiddle, (*it).bottomRight());
            it = ranges.erase(it);
            split.append(left);
            split.append(right);
        } else {
            ++it;
        }
    }
    ranges += split;
}

void QItemSelectionModelPrivate::_q_rowsAboutToBeInserted(const QModelIndex &parent,
                                                          int start, int end)
{
    Q_UNUSED(end);
    finalize();
    QList<QItemSelectionRange> split;
    QList<QItemSelectionRange>::iterator it = ranges.begin();
    for (; it != ranges.end(); ) {
        if ((*it).isValid() && (*it).parent() == parent
            && (*it).top() < start && (*it).bottom() >= start) {
            QModelIndex middleRight = model->index(start - 1, (*it).right(), (*it).parent());
            QItemSelectionRange top((*it).topLeft(), middleRight);
            QModelIndex middleLeft = model->index(start, (*it).left(), (*it).parent());
            QItemSelectionRange bottom(middleLeft, (*it).bottomRight());
            it = ranges.erase(it);
            split.append(top);
            split.append(bottom);
        } else {
            ++it;
        }
    }
    ranges += split;
}

void QItemSelectionModelPrivate::_q_layoutAboutToBeChanged()
{
    savedPersistentIndexes.clear();
    savedPersistentCurrentIndexes.clear();

    // optimization for when all indexes are selected
    // (only if there is lots of items (1000) because this is not entirely correct)
    if (ranges.isEmpty() && currentSelection.count() == 1) {
        QItemSelectionRange range = currentSelection.first();
        QModelIndex parent = range.parent();
        tableRowCount = model->rowCount(parent);
        tableColCount = model->columnCount(parent);
        if (tableRowCount * tableColCount > 1000
            && range.top() == 0
            && range.left() == 0
            && range.bottom() == tableRowCount - 1
            && range.right() == tableColCount - 1) {
            tableSelected = true;
            tableParent = parent;
            return;
        }
    }
    tableSelected = false;

    QModelIndexList indexes = ranges.indexes();
    QModelIndexList::const_iterator it;
    for (it = indexes.constBegin(); it != indexes.constEnd(); ++it)
        savedPersistentIndexes.append(QPersistentModelIndex(*it));
    indexes = currentSelection.indexes();
    for (it = indexes.constBegin(); it != indexes.constEnd(); ++it)
        savedPersistentCurrentIndexes.append(QPersistentModelIndex(*it));
}

static QItemSelection mergeIndexes(const QList<QPersistentModelIndex> &indexes)
{
    QItemSelection colSpans;
    // merge columns
    int i = 0;
    while (i < indexes.count()) {
        QModelIndex tl = indexes.at(i);
        QModelIndex br = tl;
        while (++i < indexes.count()) {
            QModelIndex next = indexes.at(i);
            if ((next.parent() == br.parent())
                 && (next.row() == br.row())
                 && (next.column() == br.column() + 1))
                br = next;
            else
                break;
        }
        colSpans.append(QItemSelectionRange(tl, br));
    }
    // merge rows
    QItemSelection rowSpans;
    i = 0;
    while (i < colSpans.count()) {
        QModelIndex tl = colSpans.at(i).topLeft();
        QModelIndex br = colSpans.at(i).bottomRight();
        QModelIndex prevTl = tl;
        while (++i < colSpans.count()) {
            QModelIndex nextTl = colSpans.at(i).topLeft();
            QModelIndex nextBr = colSpans.at(i).bottomRight();

            if (nextTl.parent() != tl.parent())
                break; // we can't merge selection ranges from different parents

            if ((nextTl.column() == prevTl.column()) && (nextBr.column() == br.column())
                && (nextTl.row() == prevTl.row() + 1) && (nextBr.row() == br.row() + 1)) {
                br = nextBr;
                prevTl = nextTl;
            } else {
                break;
            }
        }
        rowSpans.append(QItemSelectionRange(tl, br));
    }
    return rowSpans;
}

void QItemSelectionModelPrivate::_q_layoutChanged()
{
    // special case for when all indexes are selected
    if (tableSelected && tableColCount == model->columnCount(tableParent)
        && tableRowCount == model->rowCount(tableParent)) {
        ranges.clear();
        currentSelection.clear();
        int bottom = tableRowCount - 1;
        int right = tableColCount - 1;
        QModelIndex tl = model->index(0, 0, tableParent);
        QModelIndex br = model->index(bottom, right, tableParent);
        currentSelection << QItemSelectionRange(tl, br);
        tableParent = QModelIndex();
        tableSelected = false;
        return;
    }

    if (savedPersistentCurrentIndexes.isEmpty() && savedPersistentIndexes.isEmpty()) {
        // either the selection was actually empty, or we
        // didn't get the layoutAboutToBeChanged() signal
        return;
    }
    // clear the "old" selection
    ranges.clear();
    currentSelection.clear();

    // sort the "new" selection, as preparation for merging
    qStableSort(savedPersistentIndexes.begin(), savedPersistentIndexes.end());
    qStableSort(savedPersistentCurrentIndexes.begin(), savedPersistentCurrentIndexes.end());

    // update the selection by merging the individual indexes
    ranges = mergeIndexes(savedPersistentIndexes);
    currentSelection = mergeIndexes(savedPersistentCurrentIndexes);

    // release the persistent indexes
    savedPersistentIndexes.clear();
    savedPersistentCurrentIndexes.clear();
}

QItemSelectionModel::QItemSelectionModel(QAbstractItemModel *model)
    : QObject(*new QItemSelectionModelPrivate, model)
{
    d_func()->initModel(model);
}

QItemSelectionModel::QItemSelectionModel(QAbstractItemModel *model, QObject *parent)
    : QObject(*new QItemSelectionModelPrivate, parent)
{
    d_func()->initModel(model);
}

QItemSelectionModel::QItemSelectionModel(QItemSelectionModelPrivate &dd, QAbstractItemModel *model)
    : QObject(dd, model)
{
    dd.initModel(model);
}

QItemSelectionModel::~QItemSelectionModel()
{
}

void QItemSelectionModel::select(const QModelIndex &index, QItemSelectionModel::SelectionFlags command)
{
    QItemSelection selection(index, index);
    select(selection, command);
}

void QItemSelectionModel::select(const QItemSelection &selection, QItemSelectionModel::SelectionFlags command)
{
    Q_D(QItemSelectionModel);
    if (command == NoUpdate)
        return;

    // store old selection
    QItemSelection sel = selection;
    // If d->ranges is non-empty when the source model is reset the persistent indexes
    // it contains will be invalid. We can't clear them in a modelReset slot because that might already
    // be too late if another model observer is connected to the same modelReset slot and is invoked first
    // it might call select() on this selection model before any such QItemSelectionModelPrivate::_q_modelReset() slot
    // is invoked, so it would not be cleared yet. We clear it invalid ranges in it here.
    QItemSelection::iterator it = d->ranges.begin();
    while (it != d->ranges.end()) {
      if (!it->isValid())
        it = d->ranges.erase(it);
      else
        ++it;
    }

    QItemSelection old = d->ranges;
    old.merge(d->currentSelection, d->currentCommand);

    // expand selection according to SelectionBehavior
    if (command & Rows || command & Columns)
        sel = d->expandSelection(sel, command);

    // clear ranges and currentSelection
    if (command & Clear) {
        d->ranges.clear();
        d->currentSelection.clear();
    }

    // merge and clear currentSelection if Current was not set (ie. start new currentSelection)
    if (!(command & Current))
        d->finalize();

    // update currentSelection
    if (command & Toggle || command & Select || command & Deselect) {
        d->currentCommand = command;
        d->currentSelection = sel;
    }

    // generate new selection, compare with old and emit selectionChanged()
    QItemSelection newSelection = d->ranges;
    newSelection.merge(d->currentSelection, d->currentCommand);
    emitSelectionChanged(newSelection, old);
}

void QItemSelectionModel::clear()
{
    Q_D(QItemSelectionModel);
    clearSelection();
    QModelIndex previous = d->currentIndex;
    d->currentIndex = QModelIndex();
    if (previous.isValid()) {
        emit currentChanged(d->currentIndex, previous);
        emit currentRowChanged(d->currentIndex, previous);
        emit currentColumnChanged(d->currentIndex, previous);
    }
}

void QItemSelectionModel::reset()
{
    bool block = blockSignals(true);
    clear();
    blockSignals(block);
}

void QItemSelectionModel::clearSelection()
{
    Q_D(QItemSelectionModel);
    if (d->ranges.count() == 0 && d->currentSelection.count() == 0)
        return;

    select(QItemSelection(), Clear);
}


void QItemSelectionModel::setCurrentIndex(const QModelIndex &index, QItemSelectionModel::SelectionFlags command)
{
    Q_D(QItemSelectionModel);
    if (index == d->currentIndex) {
        if (command != NoUpdate)
            select(index, command); // select item
        return;
    }
    QPersistentModelIndex previous = d->currentIndex;
    d->currentIndex = index; // set current before emitting selection changed below
    if (command != NoUpdate)
        select(d->currentIndex, command); // select item
    emit currentChanged(d->currentIndex, previous);
    if (d->currentIndex.row() != previous.row() ||
            d->currentIndex.parent() != previous.parent())
        emit currentRowChanged(d->currentIndex, previous);
    if (d->currentIndex.column() != previous.column() ||
            d->currentIndex.parent() != previous.parent())
        emit currentColumnChanged(d->currentIndex, previous);
}

QModelIndex QItemSelectionModel::currentIndex() const
{
    return static_cast<QModelIndex>(d_func()->currentIndex);
}

bool QItemSelectionModel::isSelected(const QModelIndex &index) const
{
    Q_D(const QItemSelectionModel);
    if (d->model != index.model() || !index.isValid())
        return false;

    bool selected = false;
    //  search model ranges
    QList<QItemSelectionRange>::const_iterator it = d->ranges.begin();
    for (; it != d->ranges.end(); ++it) {
        if ((*it).isValid() && (*it).contains(index)) {
            selected = true;
            break;
        }
    }

    // check  currentSelection
    if (d->currentSelection.count()) {
        if ((d->currentCommand & Deselect) && selected)
            selected = !d->currentSelection.contains(index);
        else if (d->currentCommand & Toggle)
            selected ^= d->currentSelection.contains(index);
        else if ((d->currentCommand & Select) && !selected)
            selected = d->currentSelection.contains(index);
    }

    if (selected) {
        Qt::ItemFlags flags = d->model->flags(index);
        return (flags & Qt::ItemIsSelectable);
    }

    return false;
}

bool QItemSelectionModel::isRowSelected(int row, const QModelIndex &parent) const
{
    Q_D(const QItemSelectionModel);
    if (parent.isValid() && d->model != parent.model())
        return false;

    // return false if row exist in currentSelection (Deselect)
    if (d->currentCommand & Deselect && d->currentSelection.count()) {
        for (int i=0; i<d->currentSelection.count(); ++i) {
            if (d->currentSelection.at(i).parent() == parent &&
                row >= d->currentSelection.at(i).top() &&
                row <= d->currentSelection.at(i).bottom())
                return false;
        }
    }
    // return false if ranges in both currentSelection and ranges
    // intersect and have the same row contained
    if (d->currentCommand & Toggle && d->currentSelection.count()) {
        for (int i=0; i<d->currentSelection.count(); ++i)
            if (d->currentSelection.at(i).top() <= row &&
                d->currentSelection.at(i).bottom() >= row)
                for (int j=0; j<d->ranges.count(); ++j)
                    if (d->ranges.at(j).top() <= row && d->ranges.at(j).bottom() >= row
                        && d->currentSelection.at(i).intersected(d->ranges.at(j)).isValid())
                        return false;
    }
    // add ranges and currentSelection and check through them all
    QList<QItemSelectionRange>::const_iterator it;
    QList<QItemSelectionRange> joined = d->ranges;
    if (d->currentSelection.count())
        joined += d->currentSelection;
    int colCount = d->model->columnCount(parent);
    for (int column = 0; column < colCount; ++column) {
        for (it = joined.constBegin(); it != joined.constEnd(); ++it) {
            if ((*it).contains(row, column, parent)) {
                bool selectable = false;
                for (int i = column; !selectable && i <= (*it).right(); ++i) {
                    Qt::ItemFlags flags = d->model->index(row, i, parent).flags();
                    selectable = flags & Qt::ItemIsSelectable;
                }
                if (selectable){
                    column = qMax(column, (*it).right());
                    break;
                }
            }
        }
        if (it == joined.constEnd())
            return false;
    }
    return colCount > 0; // no columns means no selected items
}

bool QItemSelectionModel::isColumnSelected(int column, const QModelIndex &parent) const
{
    Q_D(const QItemSelectionModel);
    if (parent.isValid() && d->model != parent.model())
        return false;

    // return false if column exist in currentSelection (Deselect)
    if (d->currentCommand & Deselect && d->currentSelection.count()) {
        for (int i = 0; i < d->currentSelection.count(); ++i) {
            if (d->currentSelection.at(i).parent() == parent &&
                column >= d->currentSelection.at(i).left() &&
                column <= d->currentSelection.at(i).right())
                return false;
        }
    }
    // return false if ranges in both currentSelection and the selection model
    // intersect and have the same column contained
    if (d->currentCommand & Toggle && d->currentSelection.count()) {
        for (int i = 0; i < d->currentSelection.count(); ++i) {
            if (d->currentSelection.at(i).left() <= column &&
                d->currentSelection.at(i).right() >= column) {
                for (int j = 0; j < d->ranges.count(); ++j) {
                    if (d->ranges.at(j).left() <= column && d->ranges.at(j).right() >= column
                        && d->currentSelection.at(i).intersected(d->ranges.at(j)).isValid()) {
                        return false;
                    }
                }
            }
        }
    }
    // add ranges and currentSelection and check through them all
    QList<QItemSelectionRange>::const_iterator it;
    QList<QItemSelectionRange> joined = d->ranges;
    if (d->currentSelection.count())
        joined += d->currentSelection;
    int rowCount = d->model->rowCount(parent);
    for (int row = 0; row < rowCount; ++row) {
         for (it = joined.constBegin(); it != joined.constEnd(); ++it) {
             if ((*it).contains(row, column, parent)) {
                 Qt::ItemFlags flags = d->model->index(row, column, parent).flags();
                 if ((flags & Qt::ItemIsSelectable) && (flags & Qt::ItemIsEnabled)) {
                     row = qMax(row, (*it).bottom());
                     break;
                 }
             }
         }
         if (it == joined.constEnd())
             return false;
    }
    return rowCount > 0; // no rows means no selected items
}

bool QItemSelectionModel::rowIntersectsSelection(int row, const QModelIndex &parent) const
{
    Q_D(const QItemSelectionModel);
    if (parent.isValid() && d->model != parent.model())
         return false;

    QItemSelection sel = d->ranges;
    sel.merge(d->currentSelection, d->currentCommand);
    for (int i = 0; i < sel.count(); ++i) {
        int top = sel.at(i).top();
        int bottom = sel.at(i).bottom();
        int left = sel.at(i).left();
        int right = sel.at(i).right();
        if (top <= row && bottom >= row) {
            for (int j = left; j <= right; j++) {
                const Qt::ItemFlags flags = d->model->index(row, j, parent).flags();
                if ((flags & Qt::ItemIsSelectable) && (flags & Qt::ItemIsEnabled))
                    return true;
            }
        }
    }

    return false;
}

bool QItemSelectionModel::columnIntersectsSelection(int column, const QModelIndex &parent) const
{
    Q_D(const QItemSelectionModel);
    if (parent.isValid() && d->model != parent.model())
        return false;

    QItemSelection sel = d->ranges;
    sel.merge(d->currentSelection, d->currentCommand);
    for (int i = 0; i < sel.count(); ++i) {
        int left = sel.at(i).left();
        int right = sel.at(i).right();
        int top =  sel.at(i).top();
        int bottom =  sel.at(i).bottom();
        if (left <= column && right >= column) {
            for (int j = top; j <= bottom; j++) {
                const Qt::ItemFlags flags = d->model->index(j, column, parent).flags();
                if ((flags & Qt::ItemIsSelectable) && (flags & Qt::ItemIsEnabled))
                    return true;
            }
        }
    }

    return false;
}

bool QItemSelectionModel::hasSelection() const
{
    Q_D(const QItemSelectionModel);
    if (d->currentCommand & (Toggle | Deselect)) {
        QItemSelection sel = d->ranges;
        sel.merge(d->currentSelection, d->currentCommand);
        return !sel.isEmpty();
    } else {
        return !(d->ranges.isEmpty() && d->currentSelection.isEmpty());
    }
}

QModelIndexList QItemSelectionModel::selectedIndexes() const
{
    Q_D(const QItemSelectionModel);
    QItemSelection selected = d->ranges;
    selected.merge(d->currentSelection, d->currentCommand);
    return selected.indexes();
}

QModelIndexList QItemSelectionModel::selectedRows(int column) const
{
    QModelIndexList indexes;
    //the QSet contains pairs of parent modelIndex
    //and row number
    QSet< QPair<QModelIndex, int> > rowsSeen;

    const QItemSelection ranges = selection();
    for (int i = 0; i < ranges.count(); ++i) {
        const QItemSelectionRange &range = ranges.at(i);
        QModelIndex parent = range.parent();
        for (int row = range.top(); row <= range.bottom(); row++) {
            QPair<QModelIndex, int> rowDef = qMakePair(parent, row);
            if (!rowsSeen.contains(rowDef)) {
                rowsSeen << rowDef;
                if (isRowSelected(row, parent)) {
                    indexes.append(model()->index(row, column, parent));
                }
            }
        }
    }

    return indexes;
}

QModelIndexList QItemSelectionModel::selectedColumns(int row) const
{
    QModelIndexList indexes;
    //the QSet contains pairs of parent modelIndex
    //and column number
    QSet< QPair<QModelIndex, int> > columnsSeen;

    const QItemSelection ranges = selection();
    for (int i = 0; i < ranges.count(); ++i) {
        const QItemSelectionRange &range = ranges.at(i);
        QModelIndex parent = range.parent();
        for (int column = range.left(); column <= range.right(); column++) {
            QPair<QModelIndex, int> columnDef = qMakePair(parent, column);
            if (!columnsSeen.contains(columnDef)) {
                columnsSeen << columnDef;
                if (isColumnSelected(column, parent)) {
                    indexes.append(model()->index(row, column, parent));
                }
            }
        }
    }

    return indexes;
}

const QItemSelection QItemSelectionModel::selection() const
{
    Q_D(const QItemSelectionModel);
    QItemSelection selected = d->ranges;
    selected.merge(d->currentSelection, d->currentCommand);
    int i = 0;
    // make sure we have no invalid ranges
    // ###  should probably be handled more generic somewhere else
    while (i<selected.count()) {
        if (selected.at(i).isValid())
            ++i;
        else
            (selected.removeAt(i));
    }
    return selected;
}

const QAbstractItemModel *QItemSelectionModel::model() const
{
    return d_func()->model;
}

void QItemSelectionModel::emitSelectionChanged(const QItemSelection &newSelection,
                                               const QItemSelection &oldSelection)
{
    // if both selections are empty or equal we return
    if ((oldSelection.isEmpty() && newSelection.isEmpty()) ||
        oldSelection == newSelection)
        return;

    // if either selection is empty we do not need to compare
    if (oldSelection.isEmpty() || newSelection.isEmpty()) {
        emit selectionChanged(newSelection, oldSelection);
        return;
    }

    QItemSelection deselected = oldSelection;
    QItemSelection selected = newSelection;

    // remove equal ranges
    bool advance;
    for (int o = 0; o < deselected.count(); ++o) {
        advance = true;
        for (int s = 0; s < selected.count() && o < deselected.count();) {
            if (deselected.at(o) == selected.at(s)) {
                deselected.removeAt(o);
                selected.removeAt(s);
                advance = false;
            } else {
                ++s;
            }
        }
        if (advance)
            ++o;
    }

    // find intersections
    QItemSelection intersections;
    for (int o = 0; o < deselected.count(); ++o) {
        for (int s = 0; s < selected.count(); ++s) {
            if (deselected.at(o).intersects(selected.at(s)))
                intersections.append(deselected.at(o).intersected(selected.at(s)));
        }
    }

    // compare remaining ranges with intersections and split them to find deselected and selected
    for (int i = 0; i < intersections.count(); ++i) {
        // split deselected
        for (int o = 0; o < deselected.count();) {
            if (deselected.at(o).intersects(intersections.at(i))) {
                QItemSelection::split(deselected.at(o), intersections.at(i), &deselected);
                deselected.removeAt(o);
            } else {
                ++o;
            }
        }
        // split selected
        for (int s = 0; s < selected.count();) {
            if (selected.at(s).intersects(intersections.at(i))) {
                QItemSelection::split(selected.at(s), intersections.at(i), &selected);
                selected.removeAt(s);
            } else {
                ++s;
            }
        }
    }

    if (!selected.isEmpty() || !deselected.isEmpty())
        emit selectionChanged(selected, deselected);
}

#ifndef QT_NO_DEBUG_STREAM
QDebug operator<<(QDebug dbg, const QItemSelectionRange &range)
{
#ifndef Q_BROKEN_DEBUG_STREAM
    dbg.nospace() << "QItemSelectionRange(" << range.topLeft()
                  << ',' << range.bottomRight() << ')';
    return dbg.space();
#else
    qWarning("This compiler doesn't support streaming QItemSelectionRange to QDebug");
    return dbg;
    Q_UNUSED(range);
#endif
}
#endif

QT_END_NAMESPACE

#include "moc_qitemselectionmodel.cpp"

#endif // QT_NO_ITEMVIEWS