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Use the layout change hint to speed up QItemSelectionModel.

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The testcase in the bug report takes 370035 ms to sort the rows with
Qt 4, and 5646 ms in Qt 5 (when using the extra hints to layout*Changed).

That's an improvement of more than 98%.

Task-number: QTBUG-17732
Change-Id: If78f972d80c501e0cb39078228086c4f4ac8a65b
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
This commit is contained in:
Stephen Kelly 2012-09-27 11:36:23 +02:00 committed by The Qt Project
parent 0693082c95
commit d18eb260d7
3 changed files with 110 additions and 28 deletions
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106
src/corelib/itemmodels/qitemselectionmodel.cpp
View File

@ -284,12 +284,21 @@ QItemSelectionRange QItemSelectionRange::intersected(const QItemSelectionRange &
*/
/*
\internal
utility function for getting the indexes from a range
it avoid concatenating list and works on one
*/
static void rowLengthsFromRange(const QItemSelectionRange &range, QVector<QPair<QPersistentModelIndex, uint> > &result)
{
if (range.isValid() && range.model()) {
const QModelIndex topLeft = range.topLeft();
const int bottom = range.bottom();
const uint width = range.width();
const int column = topLeft.column();
for (int row = topLeft.row(); row <= bottom; ++row) {
// We don't need to keep track of ItemIsSelectable and ItemIsEnabled here. That is
// required in indexesFromRange() because that method is called from public API
// which requires the limitation.
result.push_back(qMakePair(QPersistentModelIndex(topLeft.sibling(row, column)), width));
}
}
}
template<typename ModelIndexContainer>
static void indexesFromRange(const QItemSelectionRange &range, ModelIndexContainer &result)
@ -468,6 +477,14 @@ static QVector<QPersistentModelIndex> qSelectionPersistentindexes(const QItemSel
return result;
}
static QVector<QPair<QPersistentModelIndex, uint> > qSelectionPersistentRowLengths(const QItemSelection &sel)
{
QVector<QPair<QPersistentModelIndex, uint> > result;
Q_FOREACH (const QItemSelectionRange &range, sel)
rowLengthsFromRange(range, result);
return result;
}
/*!
Merges the \a other selection with this QItemSelection using the
\a command given. This method guarantees that no ranges are overlapping.
@ -599,10 +616,10 @@ void QItemSelectionModelPrivate::initModel(QAbstractItemModel *model)
q, SLOT(_q_layoutChanged()));
QObject::connect(model, SIGNAL(columnsMoved(QModelIndex,int,int,QModelIndex,int)),
q, SLOT(_q_layoutChanged()));
QObject::connect(model, SIGNAL(layoutAboutToBeChanged()),
q, SLOT(_q_layoutAboutToBeChanged()));
QObject::connect(model, SIGNAL(layoutChanged()),
q, SLOT(_q_layoutChanged()));
QObject::connect(model, SIGNAL(layoutAboutToBeChanged(QList<QPersistentModelIndex>,QAbstractItemModel::LayoutChangeHint)),
q, SLOT(_q_layoutAboutToBeChanged(QList<QPersistentModelIndex>,QAbstractItemModel::LayoutChangeHint)));
QObject::connect(model, SIGNAL(layoutChanged(QList<QPersistentModelIndex>,QAbstractItemModel::LayoutChangeHint)),
q, SLOT(_q_layoutChanged(QList<QPersistentModelIndex>,QAbstractItemModel::LayoutChangeHint)));
}
}
@ -812,10 +829,12 @@ void QItemSelectionModelPrivate::_q_rowsAboutToBeInserted(const QModelIndex &par
preparation for the layoutChanged() signal, where the indexes can be
merged again.
*/
void QItemSelectionModelPrivate::_q_layoutAboutToBeChanged()
void QItemSelectionModelPrivate::_q_layoutAboutToBeChanged(const QList<QPersistentModelIndex> &, QAbstractItemModel::LayoutChangeHint hint)
{
savedPersistentIndexes.clear();
savedPersistentCurrentIndexes.clear();
savedPersistentRowLengths.clear();
savedPersistentCurrentRowLengths.clear();
// optimization for when all indexes are selected
// (only if there is lots of items (1000) because this is not entirely correct)
@ -836,9 +855,54 @@ void QItemSelectionModelPrivate::_q_layoutAboutToBeChanged()
}
tableSelected = false;
if (hint == QAbstractItemModel::VerticalSortHint) {
// Special case when we know we're sorting vertically. We can assume that all indexes for columns
// are displaced the same way, and therefore we only need to track an index from one column per
// row with a QPersistentModelIndex together with the length of items to the right of it
// which are displaced the same way.
// An algorithm which contains the same assumption is used to process layoutChanged.
savedPersistentRowLengths = qSelectionPersistentRowLengths(ranges);
savedPersistentCurrentRowLengths = qSelectionPersistentRowLengths(currentSelection);
} else {
savedPersistentIndexes = qSelectionPersistentindexes(ranges);
savedPersistentCurrentIndexes = qSelectionPersistentindexes(currentSelection);
}
}
/*!
\internal
*/
static QItemSelection mergeRowLengths(const QVector<QPair<QPersistentModelIndex, uint> > &rowLengths)
{
if (rowLengths.isEmpty())
return QItemSelection();
QItemSelection result;
int i = 0;
while (i < rowLengths.count()) {
const QPersistentModelIndex &tl = rowLengths.at(i).first;
if (!tl.isValid()) {
++i;
continue;
}
QPersistentModelIndex br = tl;
const uint length = rowLengths.at(i).second;
while (++i < rowLengths.count()) {
const QPersistentModelIndex &next = rowLengths.at(i).first;
if (!next.isValid())
continue;
const uint nextLength = rowLengths.at(i).second;
if ((nextLength == length)
&& (next.row() == br.row() + 1)
&& (next.parent() == br.parent())) {
br = next;
} else {
break;
}
}
result.append(QItemSelectionRange(tl, br.sibling(br.row(), length - 1)));
}
return result;
}
/*!
\internal
@ -913,7 +977,7 @@ static QItemSelection mergeIndexes(const QVector<QPersistentModelIndex> &indexes
Merge the selected indexes into selection ranges again.
*/
void QItemSelectionModelPrivate::_q_layoutChanged()
void QItemSelectionModelPrivate::_q_layoutChanged(const QList<QPersistentModelIndex> &, QAbstractItemModel::LayoutChangeHint hint)
{
// special case for when all indexes are selected
if (tableSelected && tableColCount == model->columnCount(tableParent)
@ -930,15 +994,18 @@ void QItemSelectionModelPrivate::_q_layoutChanged()
return;
}
if (savedPersistentCurrentIndexes.isEmpty() && savedPersistentIndexes.isEmpty()) {
if ((hint != QAbstractItemModel::VerticalSortHint && savedPersistentCurrentIndexes.isEmpty() && savedPersistentIndexes.isEmpty())
|| (hint == QAbstractItemModel::VerticalSortHint && savedPersistentRowLengths.isEmpty() && savedPersistentCurrentRowLengths.isEmpty())) {
// either the selection was actually empty, or we
// didn't get the layoutAboutToBeChanged() signal
return;
}
// clear the "old" selection
ranges.clear();
currentSelection.clear();
if (hint != QAbstractItemModel::VerticalSortHint) {
// sort the "new" selection, as preparation for merging
qStableSort(savedPersistentIndexes.begin(), savedPersistentIndexes.end());
qStableSort(savedPersistentCurrentIndexes.begin(), savedPersistentCurrentIndexes.end());
@ -950,6 +1017,19 @@ void QItemSelectionModelPrivate::_q_layoutChanged()
// release the persistent indexes
savedPersistentIndexes.clear();
savedPersistentCurrentIndexes.clear();
} else {
// sort the "new" selection, as preparation for merging
qStableSort(savedPersistentRowLengths.begin(), savedPersistentRowLengths.end());
qStableSort(savedPersistentCurrentRowLengths.begin(), savedPersistentCurrentRowLengths.end());
// update the selection by merging the individual indexes
ranges = mergeRowLengths(savedPersistentRowLengths);
currentSelection = mergeRowLengths(savedPersistentCurrentRowLengths);
// release the persistent indexes
savedPersistentRowLengths.clear();
savedPersistentCurrentRowLengths.clear();
}
}
/*!

4
src/corelib/itemmodels/qitemselectionmodel.h
View File

@ -222,8 +222,8 @@ private:
Q_PRIVATE_SLOT(d_func(), void _q_rowsAboutToBeRemoved(const QModelIndex&, int, int))
Q_PRIVATE_SLOT(d_func(), void _q_columnsAboutToBeInserted(const QModelIndex&, int, int))
Q_PRIVATE_SLOT(d_func(), void _q_rowsAboutToBeInserted(const QModelIndex&, int, int))
Q_PRIVATE_SLOT(d_func(), void _q_layoutAboutToBeChanged())
Q_PRIVATE_SLOT(d_func(), void _q_layoutChanged())
Q_PRIVATE_SLOT(d_func(), void _q_layoutAboutToBeChanged(const QList<QPersistentModelIndex> &parents = QList<QPersistentModelIndex>(), QAbstractItemModel::LayoutChangeHint hint = QAbstractItemModel::NoHint))
Q_PRIVATE_SLOT(d_func(), void _q_layoutChanged(const QList<QPersistentModelIndex> &parents = QList<QPersistentModelIndex>(), QAbstractItemModel::LayoutChangeHint hint = QAbstractItemModel::NoHint))
};
Q_DECLARE_OPERATORS_FOR_FLAGS(QItemSelectionModel::SelectionFlags)

6
src/corelib/itemmodels/qitemselectionmodel_p.h
View File

@ -76,8 +76,8 @@ public:
void _q_columnsAboutToBeRemoved(const QModelIndex &parent, int start, int end);
void _q_rowsAboutToBeInserted(const QModelIndex &parent, int start, int end);
void _q_columnsAboutToBeInserted(const QModelIndex &parent, int start, int end);
void _q_layoutAboutToBeChanged();
void _q_layoutChanged();
void _q_layoutAboutToBeChanged(const QList<QPersistentModelIndex> &parents = QList<QPersistentModelIndex>(), QAbstractItemModel::LayoutChangeHint hint = QAbstractItemModel::NoLayoutChangeHint);
void _q_layoutChanged(const QList<QPersistentModelIndex> &parents = QList<QPersistentModelIndex>(), QAbstractItemModel::LayoutChangeHint hint = QAbstractItemModel::NoLayoutChangeHint);
inline void remove(QList<QItemSelectionRange> &r)
{
@ -100,6 +100,8 @@ public:
QItemSelectionModel::SelectionFlags currentCommand;
QVector<QPersistentModelIndex> savedPersistentIndexes;
QVector<QPersistentModelIndex> savedPersistentCurrentIndexes;
QVector<QPair<QPersistentModelIndex, uint> > savedPersistentRowLengths;
QVector<QPair<QPersistentModelIndex, uint> > savedPersistentCurrentRowLengths;
// optimization when all indexes are selected
bool tableSelected;
QPersistentModelIndex tableParent;