QPainterPathPrivate: code tidies

* Honor the RO3, doing copies of the members where it belongs
(and not in its subclass), and properly handling the refcounting
by disabling the copy assignment

* Clean up construction of QPainterPathData by using ctor-init-lists,
getting rid of a warning because the base class copy constructor
wasn't being called by the subclass' copy constructor.

* Mark everything for cleanup in Qt 6.

Change-Id: I143a322dc816e2e12b454a9e5ffe63f1a86009a5
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

src/gui/painting/qpainterpath_p.h

@@ -64,6 +64,7 @@
 
 QT_BEGIN_NAMESPACE
 
+// ### Qt 6: merge with QPainterPathData
 class QPainterPathPrivate
 {
 public:
@@ -80,7 +81,19 @@ public:
     friend Q_GUI_EXPORT QDataStream &operator>>(QDataStream &, QPainterPath &);
 #endif
 
-    QPainterPathPrivate() : ref(1) {}
+    QPainterPathPrivate() noexcept
+        : ref(1)
+    {
+    }
+
+    QPainterPathPrivate(const QPainterPathPrivate &other) noexcept
+        : ref(1),
+          elements(other.elements)
+    {
+    }
+
+    QPainterPathPrivate &operator=(const QPainterPathPrivate &) = delete;
+    ~QPainterPathPrivate() = default;
 
 private:
     QAtomicInt ref;
@@ -166,28 +179,32 @@ public:
     QPainterPathData() :
         cStart(0),
         fillRule(Qt::OddEvenFill),
+        require_moveTo(false),
         dirtyBounds(false),
         dirtyControlBounds(false),
+        convex(false),
         pathConverter(nullptr)
     {
-        require_moveTo = false;
-        convex = false;
     }
 
     QPainterPathData(const QPainterPathData &other) :
-        QPainterPathPrivate(), cStart(other.cStart), fillRule(other.fillRule),
+        QPainterPathPrivate(other),
+        cStart(other.cStart),
+        fillRule(other.fillRule),
         bounds(other.bounds),
         controlBounds(other.controlBounds),
+        require_moveTo(false),
         dirtyBounds(other.dirtyBounds),
         dirtyControlBounds(other.dirtyControlBounds),
         convex(other.convex),
         pathConverter(nullptr)
     {
-        require_moveTo = false;
-        elements = other.elements;
     }
 
-    ~QPainterPathData() {
+    QPainterPathData &operator=(const QPainterPathData &) = delete;
+
+    ~QPainterPathData()
+    {
         delete pathConverter;
     }