QGraphicsAnchorLayout: port to QHVContainer [1/4]: local QHVContainer

This part of the patch changes the definitons of the member variables
from 'C arrays of extent 2' to QHVContainer and fixes the code where
ints were used to index into the array.

To not drown in renames, keep the locally-defined enum 'Orientation',
and create a local version of QHVContainer whose index operator is
overloaded for both Qt::Orientation and the local 'Orientation'.

Follow-up patches will remove these, then, completely.

After this patch, NOrientations is no longer used, and consequently
removed.

Change-Id: I2a241520fce4beeb87fc0e26cd6ab18f324a956a
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>

3 files changed, 47 insertions, 41 deletions

diff --git a/src/widgets/graphicsview/qgraphicsanchorlayout.cpp b/src/widgets/graphicsview/qgraphicsanchorlayout.cpp
index 4f1855a606..b7c83e32a0 100644
--- a/src/widgets/graphicsview/qgraphicsanchorlayout.cpp
+++ b/src/widgets/graphicsview/qgraphicsanchorlayout.cpp
@@ -238,8 +238,8 @@ QGraphicsAnchorLayout::~QGraphicsAnchorLayout()
     d->removeCenterConstraints(this, QGraphicsAnchorLayoutPrivate::Vertical);
     d->deleteLayoutEdges();
 
-    Q_ASSERT(d->itemCenterConstraints[0].isEmpty());
-    Q_ASSERT(d->itemCenterConstraints[1].isEmpty());
+    Q_ASSERT(d->itemCenterConstraints[Qt::Horizontal].isEmpty());
+    Q_ASSERT(d->itemCenterConstraints[Qt::Vertical].isEmpty());
     Q_ASSERT(d->items.isEmpty());
     Q_ASSERT(d->m_vertexList.isEmpty());
 }
@@ -372,7 +372,7 @@ void QGraphicsAnchorLayout::setHorizontalSpacing(qreal spacing)
 {
     Q_D(QGraphicsAnchorLayout);
 
-    d->spacings[0] = spacing;
+    d->spacings[Qt::Horizontal] = spacing;
     invalidate();
 }
 
@@ -385,7 +385,7 @@ void QGraphicsAnchorLayout::setVerticalSpacing(qreal spacing)
 {
     Q_D(QGraphicsAnchorLayout);
 
-    d->spacings[1] = spacing;
+    d->spacings[Qt::Vertical] = spacing;
     invalidate();
 }
 
@@ -404,7 +404,7 @@ void QGraphicsAnchorLayout::setSpacing(qreal spacing)
 {
     Q_D(QGraphicsAnchorLayout);
 
-    d->spacings[0] = d->spacings[1] = spacing;
+    d->spacings = {spacing, spacing};
     invalidate();
 }
 
diff --git a/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp b/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp
index 78549e4c24..9934255d25 100644
--- a/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp
+++ b/src/widgets/graphicsview/qgraphicsanchorlayout_p.cpp
@@ -621,19 +621,6 @@ QString GraphPath::toString() const
 QGraphicsAnchorLayoutPrivate::QGraphicsAnchorLayoutPrivate()
     : calculateGraphCacheDirty(true), styleInfoDirty(true)
 {
-    for (int i = 0; i < NOrientations; ++i) {
-        for (int j = 0; j < 3; ++j) {
-            sizeHints[i][j] = -1;
-        }
-        interpolationProgress[i] = -1;
-
-        spacings[i] = -1;
-        graphHasConflicts[i] = false;
-
-        layoutFirstVertex[i] = nullptr;
-        layoutCentralVertex[i] = nullptr;
-        layoutLastVertex[i] = nullptr;
-    }
 }
 
 Qt::AnchorPoint QGraphicsAnchorLayoutPrivate::oppositeEdge(Qt::AnchorPoint edge)
@@ -2032,8 +2019,8 @@ QLayoutStyleInfo &QGraphicsAnchorLayoutPrivate::styleInfo() const
 
         QStyle *style = w ? w->style() : QApplication::style();
         cachedStyleInfo = QLayoutStyleInfo(style, wid);
-        cachedStyleInfo.setDefaultSpacing(Qt::Horizontal, spacings[0]);
-        cachedStyleInfo.setDefaultSpacing(Qt::Vertical, spacings[1]);
+        cachedStyleInfo.setDefaultSpacing(Qt::Horizontal, spacings[Qt::Horizontal]);
+        cachedStyleInfo.setDefaultSpacing(Qt::Vertical, spacings[Qt::Vertical]);
 
         styleInfoDirty = false;
     }
@@ -2953,9 +2940,9 @@ bool QGraphicsAnchorLayoutPrivate::hasConflicts() const
     QGraphicsAnchorLayoutPrivate *that = const_cast<QGraphicsAnchorLayoutPrivate*>(this);
     that->calculateGraphs();
 
-    bool floatConflict = !m_floatItems[0].isEmpty() || !m_floatItems[1].isEmpty();
+    bool floatConflict = !m_floatItems[Qt::Horizontal].isEmpty() || !m_floatItems[Qt::Vertical].isEmpty();
 
-    return graphHasConflicts[0] || graphHasConflicts[1] || floatConflict;
+    return graphHasConflicts[Qt::Horizontal] || graphHasConflicts[Qt::Vertical] || floatConflict;
 }
 
 #ifdef QT_DEBUG
@@ -2966,8 +2953,8 @@ void QGraphicsAnchorLayoutPrivate::dumpGraph(const QString &name)
         qWarning("Could not write to %ls", qUtf16Printable(file.fileName()));
 
     QString str = QString::fromLatin1("digraph anchorlayout {\nnode [shape=\"rect\"]\n%1}");
-    QString dotContents = graph[0].serializeToDot();
-    dotContents += graph[1].serializeToDot();
+    QString dotContents = graph[Qt::Horizontal].serializeToDot();
+    dotContents += graph[Qt::Vertical].serializeToDot();
     file.write(str.arg(dotContents).toLocal8Bit());
 
     file.close();
diff --git a/src/widgets/graphicsview/qgraphicsanchorlayout_p.h b/src/widgets/graphicsview/qgraphicsanchorlayout_p.h
index e3f1d139b9..35211c0182 100644
--- a/src/widgets/graphicsview/qgraphicsanchorlayout_p.h
+++ b/src/widgets/graphicsview/qgraphicsanchorlayout_p.h
@@ -60,6 +60,10 @@
 #include "qgraph_p.h"
 #include "qsimplex_p.h"
 
+#include <QtGui/private/qgridlayoutengine_p.h>
+
+#include <array>
+
 QT_REQUIRE_CONFIG(graphicsview);
 
 QT_BEGIN_NAMESPACE
@@ -395,7 +399,22 @@ public:
     enum Orientation {
         Horizontal = 0,
         Vertical,
-        NOrientations
+    };
+
+    template <typename T>
+    class QHVContainer : public QT_PREPEND_NAMESPACE(QHVContainer)<T>
+    {
+        using Base = QT_PREPEND_NAMESPACE(QHVContainer)<T>;
+        static constexpr Qt::Orientation map(Orientation o) noexcept
+        { return static_cast<Qt::Orientation>(int(o) + 1); }
+    public:
+        using Base::Base;
+        using Base::operator[];
+
+        constexpr const T &operator[](Orientation o) const noexcept
+        { return this->operator[](map(o)); }
+        constexpr T &operator[](Orientation o) noexcept
+        { return this->operator[](map(o)); }
     };
 
     QGraphicsAnchorLayoutPrivate();
@@ -552,9 +571,9 @@ public:
 #endif
 
 
-    qreal spacings[NOrientations];
+    QHVContainer<qreal> spacings = {-1, -1};
     // Size hints from simplex engine
-    qreal sizeHints[2][3];
+    QHVContainer<std::array<qreal, 3>> sizeHints = {{-1, -1, -1}, {-1, -1, -1}};
 
     // Items
     QVector<QGraphicsLayoutItem *> items;
@@ -565,31 +584,31 @@ public:
     QHash<QPair<QGraphicsLayoutItem*, Qt::AnchorPoint>, QPair<AnchorVertex *, int> > m_vertexList;
 
     // Internal graph of anchorage points and anchors, for both orientations
-    Graph<AnchorVertex, AnchorData> graph[2];
+    QHVContainer<Graph<AnchorVertex, AnchorData>> graph;
 
-    AnchorVertex *layoutFirstVertex[2];
-    AnchorVertex *layoutCentralVertex[2];
-    AnchorVertex *layoutLastVertex[2];
+    QHVContainer<AnchorVertex *> layoutFirstVertex = {};
+    QHVContainer<AnchorVertex *> layoutCentralVertex = {};
+    QHVContainer<AnchorVertex *> layoutLastVertex = {};
 
     // Combined anchors in order of creation
-    QList<AnchorVertexPair *> simplifiedVertices[2];
-    QList<AnchorData *> anchorsFromSimplifiedVertices[2];
+    QHVContainer<QList<AnchorVertexPair *>> simplifiedVertices;
+    QHVContainer<QList<AnchorData *>> anchorsFromSimplifiedVertices;
 
     // Graph paths and constraints, for both orientations
-    QMultiHash<AnchorVertex *, GraphPath> graphPaths[2];
-    QList<QSimplexConstraint *> constraints[2];
-    QList<QSimplexConstraint *> itemCenterConstraints[2];
+    QHVContainer<QMultiHash<AnchorVertex *, GraphPath>> graphPaths;
+    QHVContainer<QList<QSimplexConstraint *>> constraints;
+    QHVContainer<QList<QSimplexConstraint *>> itemCenterConstraints;
 
     // The interpolation interval and progress based on the current size
     // as well as the key values (minimum, preferred and maximum)
-    Interval interpolationInterval[2];
-    qreal interpolationProgress[2];
+    QHVContainer<Interval> interpolationInterval;
+    QHVContainer<qreal> interpolationProgress = {-1, -1};
 
-    bool graphHasConflicts[2];
-    QSet<QGraphicsLayoutItem *> m_floatItems[2];
+    QHVContainer<bool> graphHasConflicts = {};
+    QHVContainer<QSet<QGraphicsLayoutItem *>> m_floatItems;
 
 #if defined(QT_DEBUG) || defined(QT_BUILD_INTERNAL)
-    bool lastCalculationUsedSimplex[2];
+    QHVContainer<bool> lastCalculationUsedSimplex;
 #endif
 
     uint calculateGraphCacheDirty : 1;