Don't rely on hasChanged() in ensureGeometries

It can be removed now because we now have a better caching
mechanism than before. It should therefore not be needed anymore.

Since nothing else calls hasChanged, we can finally get rid of it.
This simplifies the code and enables us to further improvements to the
code.

Change-Id: I51afe5a97311e3e361ae8b491ecbcd21bbedacd1
Reviewed-by: J-P Nurmi <jpnurmi@theqtcompany.com>

src/gui/util/qabstractlayoutstyleinfo.cpp

@@ -35,11 +35,4 @@
 
 QT_BEGIN_NAMESPACE
 
-bool QAbstractLayoutStyleInfo::hasChanged() const
-{
-    if (m_changed == Unknown)
-        m_changed = hasChangedCore() ? Changed : Unchanged;
-    return m_changed == Changed;
-}
-
 QT_END_NAMESPACE

src/gui/util/qabstractlayoutstyleinfo_p.h

@@ -53,13 +53,8 @@ QT_BEGIN_NAMESPACE
 
 class Q_GUI_EXPORT QAbstractLayoutStyleInfo {
 public:
-    typedef enum {
-        Unknown = 0,
-        Changed,
-        Unchanged
-    } ChangedState;
 
-    QAbstractLayoutStyleInfo() : m_isWindow(false), m_changed(Changed) {}
+    QAbstractLayoutStyleInfo() : m_isWindow(false) {}
     virtual ~QAbstractLayoutStyleInfo() {}
     virtual qreal combinedLayoutSpacing(QLayoutPolicy::ControlTypes /*controls1*/,
                                         QLayoutPolicy::ControlTypes /*controls2*/, Qt::Orientation /*orientation*/) const {
@@ -74,15 +69,9 @@ public:
 
     virtual qreal spacing(Qt::Orientation orientation) const = 0;
 
-    virtual bool hasChangedCore() const = 0;
+    virtual bool hasChangedCore() const { return false; }   // ### Remove when usage is gone from subclasses
 
-    void updateChanged(ChangedState change) {
-        m_changed = change;
-    }
-
-    bool hasChanged() const;
-
-    virtual void invalidate() { updateChanged(Changed);}
+    virtual void invalidate() { }
 
     virtual qreal windowMargin(Qt::Orientation orientation) const = 0;
 
@@ -92,7 +81,9 @@ public:
 
 protected:
     unsigned m_isWindow : 1;
-    mutable unsigned m_changed : 2;
+    mutable unsigned m_hSpacingState: 2;
+    mutable unsigned m_vSpacingState: 2;
+    mutable qreal m_spacing[2];
 };
 
 QT_END_NAMESPACE

src/gui/util/qgridlayoutengine.cpp

@@ -1590,7 +1590,7 @@ Qt::Orientation QGridLayoutEngine::constraintOrientation() const
 void QGridLayoutEngine::ensureGeometries(const QSizeF &size,
                                          const QAbstractLayoutStyleInfo *styleInfo) const
 {
-    if (!styleInfo->hasChanged() && q_cachedSize == size)
+    if (q_cachedSize == size)
         return;
 
     q_cachedSize = size;

src/widgets/graphicsview/qgraphicsgridlayout.cpp

@@ -108,7 +108,6 @@ QGraphicsLayoutStyleInfo *QGraphicsGridLayoutPrivate::styleInfo() const
 {
     if (!m_styleInfo)
         m_styleInfo = new QGraphicsLayoutStyleInfo(this);
-    m_styleInfo->updateChanged(QAbstractLayoutStyleInfo::Unknown);
     return m_styleInfo;
 }
 

src/widgets/graphicsview/qgraphicslayoutstyleinfo_p.h

@@ -77,13 +77,6 @@ public:
         QAbstractLayoutStyleInfo::invalidate();
     }
 
-    virtual bool hasChangedCore() const Q_DECL_OVERRIDE
-    {
-        QStyle *s = m_style;
-        // Note that style() will change m_style
-        return s != style();
-    }
-
     QWidget *widget() const;
     QStyle *style() const;
 

src/widgets/graphicsview/qgraphicslinearlayout.cpp

@@ -173,7 +173,6 @@ QGraphicsLayoutStyleInfo *QGraphicsLinearLayoutPrivate::styleInfo() const
 {
     if (!m_styleInfo)
         m_styleInfo = new QGraphicsLayoutStyleInfo(this);
-    m_styleInfo->updateChanged(QAbstractLayoutStyleInfo::Unknown);
     return m_styleInfo;
 }