widgets: Use QList::reserve(), reduces reallocations.

Change-Id: I49cc03f365c77f142f62c8e77505ec09723a44d9
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>

src/widgets/accessible/itemviews.cpp

@@ -198,7 +198,9 @@ QList<QAccessibleInterface *> QAccessibleTable::selectedCells() const
     QList<QAccessibleInterface*> cells;
     if (!view()->selectionModel())
         return cells;
-    Q_FOREACH (const QModelIndex &index, view()->selectionModel()->selectedIndexes())
+    const QModelIndexList selectedIndexes = view()->selectionModel()->selectedIndexes();
+    cells.reserve(selectedIndexes.size());
+    Q_FOREACH (const QModelIndex &index, selectedIndexes)
         cells.append(child(logicalIndex(index)));
     return cells;
 }
@@ -208,9 +210,11 @@ QList<int> QAccessibleTable::selectedColumns() const
     if (!view()->selectionModel())
         return QList<int>();
     QList<int> columns;
-    Q_FOREACH (const QModelIndex &index, view()->selectionModel()->selectedColumns()) {
+    const QModelIndexList selectedColumns = view()->selectionModel()->selectedColumns();
+    columns.reserve(selectedColumns.size());
+    Q_FOREACH (const QModelIndex &index, selectedColumns)
         columns.append(index.column());
-    }
+
     return columns;
 }
 
@@ -219,9 +223,11 @@ QList<int> QAccessibleTable::selectedRows() const
     if (!view()->selectionModel())
         return QList<int>();
     QList<int> rows;
-    Q_FOREACH (const QModelIndex &index, view()->selectionModel()->selectedRows()) {
+    const QModelIndexList selectedRows = view()->selectionModel()->selectedRows();
+    rows.reserve(selectedRows.size());
+    Q_FOREACH (const QModelIndex &index, selectedRows)
         rows.append(index.row());
-    }
+
     return rows;
 }
 

src/widgets/dialogs/qfiledialog.cpp

@@ -1189,12 +1189,17 @@ QList<QUrl> QFileDialogPrivate::userSelectedFiles() const
     if (!usingWidgets())
         return addDefaultSuffixToUrls(selectedFiles_sys());
 
-    foreach (const QModelIndex &index, qFileDialogUi->listView->selectionModel()->selectedRows())
+    const QModelIndexList selectedRows = qFileDialogUi->listView->selectionModel()->selectedRows();
+    files.reserve(selectedRows.size());
+    foreach (const QModelIndex &index, selectedRows)
         files.append(QUrl::fromLocalFile(index.data(QFileSystemModel::FilePathRole).toString()));
 
-    if (files.isEmpty() && !lineEdit()->text().isEmpty())
+    if (files.isEmpty() && !lineEdit()->text().isEmpty()) {
-        foreach (const QString &path, typedFiles())
+        const QStringList typedFilesList = typedFiles();
+        files.reserve(typedFilesList.size());
+        foreach (const QString &path, typedFilesList)
             files.append(QUrl::fromLocalFile(path));
+    }
 
     return files;
 }
@@ -1228,7 +1233,9 @@ QStringList QFileDialogPrivate::addDefaultSuffixToFiles(const QStringList &files
 QList<QUrl> QFileDialogPrivate::addDefaultSuffixToUrls(const QList<QUrl> &urlsToFix) const
 {
     QList<QUrl> urls;
-    for (int i=0; i<urlsToFix.size(); ++i) {
+    const int numUrlsToFix = urlsToFix.size();
+    urls.reserve(numUrlsToFix);
+    for (int i = 0; i < numUrlsToFix; ++i) {
         QUrl url = urlsToFix.at(i);
         // if the filename has no suffix, add the default suffix
         const QString defaultSuffix = options->defaultSuffix();
@@ -1252,7 +1259,9 @@ QStringList QFileDialog::selectedFiles() const
     Q_D(const QFileDialog);
 
     QStringList files;
-    foreach (const QUrl &file, d->userSelectedFiles())
+    const QList<QUrl> userSelectedFiles = d->userSelectedFiles();
+    files.reserve(userSelectedFiles.size());
+    foreach (const QUrl &file, userSelectedFiles)
         files.append(file.toLocalFile());
     if (files.isEmpty() && d->usingWidgets()) {
         const FileMode fm = fileMode();
@@ -1277,7 +1286,9 @@ QList<QUrl> QFileDialog::selectedUrls() const
         return d->userSelectedFiles();
     } else {
         QList<QUrl> urls;
-        foreach (const QString &file, selectedFiles())
+        const QStringList selectedFileList = selectedFiles();
+        urls.reserve(selectedFileList.size());
+        foreach (const QString &file, selectedFileList)
             urls.append(QUrl::fromLocalFile(file));
         return urls;
     }
@@ -1356,7 +1367,9 @@ QStringList qt_strip_filters(const QStringList &filters)
 {
     QStringList strippedFilters;
     QRegExp r(QString::fromLatin1(QPlatformFileDialogHelper::filterRegExp));
-    for (int i = 0; i < filters.count(); ++i) {
+    const int numFilters = filters.count();
+    strippedFilters.reserve(numFilters);
+    for (int i = 0; i < numFilters; ++i) {
         QString filterName;
         int index = r.indexIn(filters[i]);
         if (index >= 0)
@@ -1391,7 +1404,9 @@ void QFileDialog::setNameFilters(const QStringList &filters)
     Q_D(QFileDialog);
     d->defaultFileTypes = (filters == QStringList(QFileDialog::tr("All Files (*)")));
     QStringList cleanedFilters;
-    for (int i = 0; i < filters.count(); ++i) {
+    const int numFilters = filters.count();
+    cleanedFilters.reserve(numFilters);
+    for (int i = 0; i < numFilters; ++i) {
         cleanedFilters << filters[i].simplified();
     }
     d->options->setNameFilters(cleanedFilters);
@@ -2186,6 +2201,7 @@ QStringList QFileDialog::getOpenFileNames(QWidget *parent,
     const QStringList schemes = QStringList(QStringLiteral("file"));
     const QList<QUrl> selectedUrls = getOpenFileUrls(parent, caption, QUrl::fromLocalFile(dir), filter, selectedFilter, options, schemes);
     QStringList fileNames;
+    fileNames.reserve(selectedUrls.size());
     foreach (const QUrl &url, selectedUrls)
         fileNames << url.toLocalFile();
     return fileNames;
@@ -2662,7 +2678,9 @@ void QFileDialogPrivate::saveSettings()
         settings.setValue(QLatin1String("treeViewHeader"), qFileDialogUi->treeView->header()->saveState());
     }
     QStringList historyUrls;
-    foreach (const QString &path, q->history())
+    const QStringList history = q->history();
+    historyUrls.reserve(history.size());
+    foreach (const QString &path, history)
         historyUrls << QUrl::fromLocalFile(path).toString();
     settings.setValue(QLatin1String("history"), historyUrls);
     settings.setValue(QLatin1String("lastVisited"), lastVisitedDir()->toString());

src/widgets/dialogs/qfilesystemmodel.cpp

@@ -1183,8 +1183,11 @@ void QFileSystemModel::sort(int column, Qt::SortOrder order)
     emit layoutAboutToBeChanged();
     QModelIndexList oldList = persistentIndexList();
     QList<QPair<QFileSystemModelPrivate::QFileSystemNode*, int> > oldNodes;
-    for (int i = 0; i < oldList.count(); ++i) {
+    const int nodeCount = oldList.count();
-        QPair<QFileSystemModelPrivate::QFileSystemNode*, int> pair(d->node(oldList.at(i)), oldList.at(i).column());
+    oldNodes.reserve(nodeCount);
+    for (int i = 0; i < nodeCount; ++i) {
+        const QModelIndex &oldNode = oldList.at(i);
+        QPair<QFileSystemModelPrivate::QFileSystemNode*, int> pair(d->node(oldNode), oldNode.column());
         oldNodes.append(pair);
     }
 
@@ -1197,9 +1200,10 @@ void QFileSystemModel::sort(int column, Qt::SortOrder order)
     d->sortOrder = order;
 
     QModelIndexList newList;
-    for (int i = 0; i < oldNodes.count(); ++i) {
+    for (int i = 0; i < nodeCount; ++i) {
-        QModelIndex idx = d->index(oldNodes.at(i).first);
+        const QPair<QFileSystemModelPrivate::QFileSystemNode*, int> &oldNode = oldNodes.at(i);
-        idx = idx.sibling(idx.row(), oldNodes.at(i).second);
+        QModelIndex idx = d->index(oldNode.first);
+        idx = idx.sibling(idx.row(), oldNode.second);
         newList.append(idx);
     }
     changePersistentIndexList(oldList, newList);
@@ -1648,7 +1652,9 @@ QStringList QFileSystemModel::nameFilters() const
     Q_D(const QFileSystemModel);
     QStringList filters;
 #ifndef QT_NO_REGEXP
-    for (int i = 0; i < d->nameFilters.size(); ++i) {
+    const int numNameFilters = d->nameFilters.size();
+    filters.reserve(numNameFilters);
+    for (int i = 0; i < numNameFilters; ++i) {
          filters << d->nameFilters.at(i).pattern();
     }
 #endif

src/widgets/dialogs/qfontdialog.cpp

@@ -619,6 +619,7 @@ void QFontDialogPrivate::updateSizes()
         int i = 0;
         int current = -1;
         QStringList str_sizes;
+        str_sizes.reserve(sizes.size());
         for(QList<int>::const_iterator it = sizes.constBegin(); it != sizes.constEnd(); ++it) {
             str_sizes.append(QString::number(*it));
             if (current == -1 && *it == size)

src/widgets/dialogs/qinputdialog.cpp

@@ -791,6 +791,7 @@ QStringList QInputDialog::comboBoxItems() const
     QStringList result;
     if (d->comboBox) {
         const int count = d->comboBox->count();
+        result.reserve(count);
         for (int i = 0; i < count; ++i)
             result.append(d->comboBox->itemText(i));
     }

src/widgets/dialogs/qsidebar.cpp

@@ -274,7 +274,9 @@ void QUrlModel::addUrls(const QList<QUrl> &list, int row, bool move)
 QList<QUrl> QUrlModel::urls() const
 {
     QList<QUrl> list;
-    for (int i = 0; i < rowCount(); ++i)
+    const int numRows = rowCount();
+    list.reserve(numRows);
+    for (int i = 0; i < numRows; ++i)
         list.append(data(index(i, 0), UrlRole).toUrl());
     return list;
 }
@@ -334,10 +336,12 @@ void QUrlModel::dataChanged(const QModelIndex &topLeft, const QModelIndex &botto
 void QUrlModel::layoutChanged()
 {
     QStringList paths;
-    for (int i = 0; i < watching.count(); ++i)
+    const int numPaths = watching.count();
+    paths.reserve(numPaths);
+    for (int i = 0; i < numPaths; ++i)
         paths.append(watching.at(i).second);
     watching.clear();
-    for (int i = 0; i < paths.count(); ++i) {
+    for (int i = 0; i < numPaths; ++i) {
         QString path = paths.at(i);
         QModelIndex newIndex = fileSystemModel->index(path);
         watching.append(QPair<QModelIndex, QString>(newIndex, path));
@@ -453,12 +457,14 @@ void QSidebar::removeEntry()
 {
     QList<QModelIndex> idxs = selectionModel()->selectedIndexes();
     QList<QPersistentModelIndex> indexes;
-    for (int i = 0; i < idxs.count(); i++)
+    const int numIndexes = idxs.count();
+    for (int i = 0; i < numIndexes; i++)
         indexes.append(idxs.at(i));
 
-    for (int i = 0; i < indexes.count(); ++i)
+    for (int i = 0; i < numIndexes; ++i) {
         if (!indexes.at(i).data(QUrlModel::UrlRole).toUrl().path().isEmpty())
             model()->removeRow(indexes.at(i).row());
+    }
 }
 
 /*!

src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp

@@ -752,8 +752,10 @@ static AnchorData *createSequence(Graph<AnchorVertex, AnchorData> *graph,
     AnchorVertex *prev = before;
     QVector<AnchorData *> edges;
 
+    const int numVertices = vertices.count();
+    edges.reserve(numVertices + 1);
     // Take from the graph, the edges that will be simplificated
-    for (int i = 0; i < vertices.count(); ++i) {
+    for (int i = 0; i < numVertices; ++i) {
         AnchorVertex *next = vertices.at(i);
         AnchorData *ad = graph->takeEdge(prev, next);
         Q_ASSERT(ad);
@@ -2569,6 +2571,7 @@ QGraphicsAnchorLayoutPrivate::getGraphParts(Orientation orientation)
 
     if (!remainingConstraints.isEmpty()) {
         QList<QSimplexConstraint *> nonTrunkConstraints;
+        nonTrunkConstraints.reserve(remainingConstraints.size());
         QLinkedList<QSimplexConstraint *>::iterator it = remainingConstraints.begin();
         while (it != remainingConstraints.end()) {
             nonTrunkConstraints += *it;

src/widgets/graphicsview/qgraphicsitemanimation.cpp

@@ -284,7 +284,9 @@ void QGraphicsItemAnimation::setPosAt(qreal step, const QPointF &pos)
 QList<QPair<qreal, QPointF> > QGraphicsItemAnimation::posList() const
 {
     QList<QPair<qreal, QPointF> > list;
-    for (int i = 0; i < d->xPosition.size(); ++i)
+    const int xPosCount = d->xPosition.size();
+    list.reserve(xPosCount);
+    for (int i = 0; i < xPosCount; ++i)
         list << QPair<qreal, QPointF>(d->xPosition.at(i).step, QPointF(d->xPosition.at(i).value, d->yPosition.at(i).value));
 
     return list;
@@ -338,7 +340,9 @@ void QGraphicsItemAnimation::setRotationAt(qreal step, qreal angle)
 QList<QPair<qreal, qreal> > QGraphicsItemAnimation::rotationList() const
 {
     QList<QPair<qreal, qreal> > list;
-    for (int i = 0; i < d->rotation.size(); ++i)
+    const int numRotations = d->rotation.size();
+    list.reserve(numRotations);
+    for (int i = 0; i < numRotations; ++i)
         list << QPair<qreal, qreal>(d->rotation.at(i).step, d->rotation.at(i).value);
 
     return list;
@@ -386,7 +390,9 @@ void QGraphicsItemAnimation::setTranslationAt(qreal step, qreal dx, qreal dy)
 QList<QPair<qreal, QPointF> > QGraphicsItemAnimation::translationList() const
 {
     QList<QPair<qreal, QPointF> > list;
-    for (int i = 0; i < d->xTranslation.size(); ++i)
+    const int numTranslations = d->xTranslation.size();
+    list.reserve(numTranslations);
+    for (int i = 0; i < numTranslations; ++i)
         list << QPair<qreal, QPointF>(d->xTranslation.at(i).step, QPointF(d->xTranslation.at(i).value, d->yTranslation.at(i).value));
 
     return list;
@@ -435,7 +441,9 @@ void QGraphicsItemAnimation::setScaleAt(qreal step, qreal sx, qreal sy)
 QList<QPair<qreal, QPointF> > QGraphicsItemAnimation::scaleList() const
 {
     QList<QPair<qreal, QPointF> > list;
-    for (int i = 0; i < d->horizontalScale.size(); ++i)
+    const int numScales = d->horizontalScale.size();
+    list.reserve(numScales);
+    for (int i = 0; i < numScales; ++i)
         list << QPair<qreal, QPointF>(d->horizontalScale.at(i).step, QPointF(d->horizontalScale.at(i).value, d->verticalScale.at(i).value));
 
     return list;
@@ -483,7 +491,9 @@ void QGraphicsItemAnimation::setShearAt(qreal step, qreal sh, qreal sv)
 QList<QPair<qreal, QPointF> > QGraphicsItemAnimation::shearList() const
 {
     QList<QPair<qreal, QPointF> > list;
-    for (int i = 0; i < d->horizontalShear.size(); ++i)
+    const int numShears = d->horizontalShear.size();
+    list.reserve(numShears);
+    for (int i = 0; i < numShears; ++i)
         list << QPair<qreal, QPointF>(d->horizontalShear.at(i).step, QPointF(d->horizontalShear.at(i).value, d->verticalShear.at(i).value));
 
     return list;

src/widgets/graphicsview/qgraphicssceneindex.cpp

@@ -520,7 +520,9 @@ QList<QGraphicsItem *> QGraphicsSceneIndex::estimateTopLevelItems(const QRectF &
     scened->ensureSortedTopLevelItems();
     if (order == Qt::DescendingOrder) {
         QList<QGraphicsItem *> sorted;
-        for (int i = scened->topLevelItems.size() - 1; i >= 0; --i)
+        const int numTopLevelItems = scened->topLevelItems.size();
+        sorted.reserve(numTopLevelItems);
+        for (int i = numTopLevelItems - 1; i >= 0; --i)
             sorted << scened->topLevelItems.at(i);
         return sorted;
     }

src/widgets/itemviews/qlistwidget.cpp

@@ -1699,7 +1699,9 @@ QList<QListWidgetItem*> QListWidget::selectedItems() const
     Q_D(const QListWidget);
     QModelIndexList indexes = selectionModel()->selectedIndexes();
     QList<QListWidgetItem*> items;
-    for (int i = 0; i < indexes.count(); ++i)
+    const int numIndexes = indexes.count();
+    items.reserve(numIndexes);
+    for (int i = 0; i < numIndexes; ++i)
         items.append(d->listModel()->at(indexes.at(i).row()));
     return items;
 }

src/widgets/itemviews/qtableview.cpp

@@ -1884,6 +1884,7 @@ void QTableView::setSelection(const QRect &rect, QItemSelectionModel::SelectionF
                     break;
             }
         } while (expanded);
+         selection.reserve((right - left + 1) * (bottom - top + 1));
          for (int horizontal = left; horizontal <= right; ++horizontal) {
              int column = d->logicalColumn(horizontal);
              for (int vertical = top; vertical <= bottom; ++vertical) {
@@ -1897,6 +1898,7 @@ void QTableView::setSelection(const QRect &rect, QItemSelectionModel::SelectionF
          int left = d->visualColumn(tl.column());
          int bottom = d->visualRow(br.row());
          int right = d->visualColumn(br.column());
+         selection.reserve((right - left + 1) * (bottom - top + 1));
          for (int horizontal = left; horizontal <= right; ++horizontal) {
              int column = d->logicalColumn(horizontal);
              for (int vertical = top; vertical <= bottom; ++vertical) {
@@ -1908,6 +1910,7 @@ void QTableView::setSelection(const QRect &rect, QItemSelectionModel::SelectionF
     } else if (horizontalMoved) {
         int left = d->visualColumn(tl.column());
         int right = d->visualColumn(br.column());
+        selection.reserve(right - left + 1);
         for (int visual = left; visual <= right; ++visual) {
             int column = d->logicalColumn(visual);
             QModelIndex topLeft = d->model->index(tl.row(), column, d->root);
@@ -1917,6 +1920,7 @@ void QTableView::setSelection(const QRect &rect, QItemSelectionModel::SelectionF
     } else if (verticalMoved) {
         int top = d->visualRow(tl.row());
         int bottom = d->visualRow(br.row());
+        selection.reserve(bottom - top + 1);
         for (int visual = top; visual <= bottom; ++visual) {
             int row = d->logicalRow(visual);
             QModelIndex topLeft = d->model->index(row, tl.column(), d->root);

src/widgets/itemviews/qtablewidget.cpp

@@ -507,11 +507,15 @@ void QTableModel::sort(int column, Qt::SortOrder order)
     QVector<QTableWidgetItem*> sorted_table(tableItems.count());
     QModelIndexList from;
     QModelIndexList to;
-    for (int i = 0; i < rowCount(); ++i) {
+    const int numRows = rowCount();
+    const int numColumns = columnCount();
+    from.reserve(numRows * numColumns);
+    to.reserve(numRows * numColumns);
+    for (int i = 0; i < numRows; ++i) {
         int r = (i < sortable.count()
                  ? sortable.at(i).second
                  : unsortable.at(i - sortable.count()));
-        for (int c = 0; c < columnCount(); ++c) {
+        for (int c = 0; c < numColumns; ++c) {
             sorted_table[tableIndex(i, c)] = item(r, c);
             from.append(createIndex(r, c));
             to.append(createIndex(i, c));

src/widgets/widgets/qabstractscrollarea.cpp

@@ -210,10 +210,12 @@ QWidgetList QAbstractScrollAreaScrollBarContainer::widgets(LogicalPosition posit
     QWidgetList list;
     const int scrollBarIndex = scrollBarLayoutIndex();
     if (position == LogicalLeft) {
+        list.reserve(scrollBarIndex);
         for (int i = 0; i < scrollBarIndex; ++i)
             list.append(layout->itemAt(i)->widget());
     } else if (position == LogicalRight) {
         const int layoutItemCount = layout->count();
+        list.reserve(layoutItemCount - (scrollBarIndex + 1));
         for (int i = scrollBarIndex + 1; i < layoutItemCount; ++i)
             list.append(layout->itemAt(i)->widget());
     }

src/widgets/widgets/qcombobox.cpp

@@ -2263,6 +2263,7 @@ void QComboBox::insertItems(int index, const QStringList &list)
     // construct a QStandardItem, reducing the number of expensive signals from the model
     if (QStandardItemModel *m = qobject_cast<QStandardItemModel*>(d->model)) {
         QList<QStandardItem *> items;
+        items.reserve(insertCount);
         QStandardItem *hiddenRoot = m->invisibleRootItem();
         for (int i = 0; i < insertCount; ++i)
             items.append(new QStandardItem(list.at(i)));

src/widgets/widgets/qdockarealayout.cpp

@@ -2211,8 +2211,10 @@ QSet<QTabBar*> QDockAreaLayoutInfo::usedTabBars() const
 QSet<QWidget*> QDockAreaLayoutInfo::usedSeparatorWidgets() const
 {
     QSet<QWidget*> result;
+    const int numSeparatorWidgets = separatorWidgets.count();
+    result.reserve(numSeparatorWidgets);
 
-    for (int i = 0; i < separatorWidgets.count(); ++i)
+    for (int i = 0; i < numSeparatorWidgets; ++i)
         result << separatorWidgets.at(i);
 
     for (int i = 0; i < item_list.count(); ++i) {

src/widgets/widgets/qsplitter.cpp

@@ -1502,8 +1502,11 @@ QList<int> QSplitter::sizes() const
     Q_D(const QSplitter);
     ensurePolished();
 
+    const int numSizes = d->list.size();
     QList<int> list;
-    for (int i = 0; i < d->list.size(); ++i) {
+    list.reserve(numSizes);
+
+    for (int i = 0; i < numSizes; ++i) {
         QSplitterLayoutStruct *s = d->list.at(i);
         list.append(d->pick(s->rect.size()));
     }
@@ -1598,8 +1601,10 @@ QByteArray QSplitter::saveState() const
 
     stream << qint32(SplitterMagic);
     stream << qint32(version);
+    const int numSizes = d->list.size();
     QList<int> list;
-    for (int i = 0; i < d->list.size(); ++i) {
+    list.reserve(numSizes);
+    for (int i = 0; i < numSizes; ++i) {
         QSplitterLayoutStruct *s = d->list.at(i);
         list.append(s->sizer);
     }

src/widgets/widgets/qwidgettextcontrol.cpp

@@ -2439,10 +2439,13 @@ QList<QTextEdit::ExtraSelection> QWidgetTextControl::extraSelections() const
 {
     Q_D(const QWidgetTextControl);
     QList<QTextEdit::ExtraSelection> selections;
-    for (int i = 0; i < d->extraSelections.count(); ++i) {
+    const int numExtraSelections = d->extraSelections.count();
+    selections.reserve(numExtraSelections);
+    for (int i = 0; i < numExtraSelections; ++i) {
         QTextEdit::ExtraSelection sel;
-        sel.cursor = d->extraSelections.at(i).cursor;
+        const QAbstractTextDocumentLayout::Selection &sel2 = d->extraSelections.at(i);
-        sel.format = d->extraSelections.at(i).format;
+        sel.cursor = sel2.cursor;
+        sel.format = sel2.format;
         selections.append(sel);
     }
     return selections;