QtWidgets: replace uses of inefficient QList<QPair>s with QVectors

These QPairs are larger than a void*, so holding them in QLists
is needlessly inefficient. Worse, the code could come to depend
on the fragile property of (inefficient) QLists that references
to elements therein never are invalidated.

Fix by holding them in QVector instead.

Change-Id: I3c205f5326cfd96482563078bdca1747d718457f
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

src/widgets/dialogs/qsidebar_p.h

@@ -55,6 +55,7 @@
 #include <qstandarditemmodel.h>
 #include <qstyleditemdelegate.h>
 #include <qurl.h>
+#include <qvector.h>
 
 #ifndef QT_NO_FILEDIALOG
 
@@ -106,7 +107,7 @@ private:
     void changed(const QString &path);
     void addIndexToWatch(const QString &path, const QModelIndex &index);
     QFileSystemModel *fileSystemModel;
-    QList<QPair<QModelIndex, QString> > watching;
+    QVector<QPair<QModelIndex, QString> > watching;
     QList<QUrl> invalidUrls;
 };
 

src/widgets/graphicsview/qgraph_p.h

@@ -211,8 +211,8 @@ public:
         return setOfVertices;
     }
 
-    QList<QPair<Vertex*, Vertex*> > connections() const {
-        QList<QPair<Vertex*, Vertex*> > conns;
+    QVector<QPair<Vertex*, Vertex*> > connections() const {
+        QVector<QPair<Vertex*, Vertex*> > conns;
         for (const_iterator it = constBegin(); it != constEnd(); ++it) {
             Vertex *from = it.from();
             Vertex *to = it.to();

src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp

@@ -1266,7 +1266,7 @@ void QGraphicsAnchorLayoutPrivate::restoreSimplifiedGraph(Orientation orientatio
 
     // Restore anchor simplification
     Graph<AnchorVertex, AnchorData> &g = graph[orientation];
-    QList<QPair<AnchorVertex*, AnchorVertex*> > connections = g.connections();
+    QVector<QPair<AnchorVertex*, AnchorVertex*> > connections = g.connections();
     for (int i = 0; i < connections.count(); ++i) {
         AnchorVertex *v1 = connections.at(i).first;
         AnchorVertex *v2 = connections.at(i).second;
@@ -2295,7 +2295,7 @@ bool QGraphicsAnchorLayoutPrivate::calculateNonTrunk(const QList<QSimplexConstra
 void QGraphicsAnchorLayoutPrivate::refreshAllSizeHints(Orientation orientation)
 {
     Graph<AnchorVertex, AnchorData> &g = graph[orientation];
-    QList<QPair<AnchorVertex *, AnchorVertex *> > vertices = g.connections();
+    QVector<QPair<AnchorVertex *, AnchorVertex *> > vertices = g.connections();
 
     QLayoutStyleInfo styleInf = styleInfo();
     for (int i = 0; i < vertices.count(); ++i) {
@@ -2388,7 +2388,7 @@ void QGraphicsAnchorLayoutPrivate::constraintsFromPaths(Orientation orientation)
 void QGraphicsAnchorLayoutPrivate::updateAnchorSizes(Orientation orientation)
 {
     Graph<AnchorVertex, AnchorData> &g = graph[orientation];
-    const QList<QPair<AnchorVertex *, AnchorVertex *> > &vertices = g.connections();
+    const QVector<QPair<AnchorVertex *, AnchorVertex *> > &vertices = g.connections();
 
     for (int i = 0; i < vertices.count(); ++i) {
         AnchorData *ad = g.edgeData(vertices.at(i).first, vertices.at(i).second);

src/widgets/itemviews/qtreeview.cpp

@@ -3777,8 +3777,8 @@ QRect QTreeViewPrivate::itemDecorationRect(const QModelIndex &index) const
     return q->style()->subElementRect(QStyle::SE_TreeViewDisclosureItem, &opt, q);
 }
 
-QList<QPair<int, int> > QTreeViewPrivate::columnRanges(const QModelIndex &topIndex,
-                                                          const QModelIndex &bottomIndex) const
+QVector<QPair<int, int> > QTreeViewPrivate::columnRanges(const QModelIndex &topIndex,
+                                                         const QModelIndex &bottomIndex) const
 {
     const int topVisual = header->visualIndex(topIndex.column()),
         bottomVisual = header->visualIndex(bottomIndex.column());
@@ -3798,7 +3798,7 @@ QList<QPair<int, int> > QTreeViewPrivate::columnRanges(const QModelIndex &topInd
     //let's sort the list
     std::sort(logicalIndexes.begin(), logicalIndexes.end());
 
-    QList<QPair<int, int> > ret;
+    QVector<QPair<int, int> > ret;
     QPair<int, int> current;
     current.first = -2; // -1 is not enough because -1+1 = 0
     current.second = -2;
@@ -3832,8 +3832,8 @@ void QTreeViewPrivate::select(const QModelIndex &topIndex, const QModelIndex &bo
     const int top = viewIndex(topIndex),
         bottom = viewIndex(bottomIndex);
 
-    const QList< QPair<int, int> > colRanges = columnRanges(topIndex, bottomIndex);
-    QList< QPair<int, int> >::const_iterator it;
+    const QVector<QPair<int, int> > colRanges = columnRanges(topIndex, bottomIndex);
+    QVector<QPair<int, int> >::const_iterator it;
     for (it = colRanges.begin(); it != colRanges.end(); ++it) {
         const int left = (*it).first,
             right = (*it).second;

src/widgets/itemviews/qtreeview_p.h

@@ -54,6 +54,7 @@
 #include "private/qabstractitemview_p.h"
 #include <QtCore/qvariantanimation.h>
 #include <QtCore/qabstractitemmodel.h>
+#include <QtCore/qvector.h>
 
 #ifndef QT_NO_TREEVIEW
 
@@ -164,7 +165,7 @@ public:
     QRect itemDecorationRect(const QModelIndex &index) const;
 
 
-    QList<QPair<int, int> > columnRanges(const QModelIndex &topIndex, const QModelIndex &bottomIndex) const;
+    QVector<QPair<int, int> > columnRanges(const QModelIndex &topIndex, const QModelIndex &bottomIndex) const;
     void select(const QModelIndex &start, const QModelIndex &stop, QItemSelectionModel::SelectionFlags command);
 
     QPair<int,int> startAndEndColumns(const QRect &rect) const;