QRegion: add move ctor

After this change, this was the distribution of calls in
QtGui and QtWidgets when the patch was developed for 5.4:

      QtGui  QtWidgets
move  23     63
copy  23     36

Change-Id: If3f536e52fc242c585e7fa0662049c0657efcc9c
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@theqtcompany.com>
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>

2 files changed, 12 insertions, 0 deletions

diff --git a/src/gui/painting/qregion.cpp b/src/gui/painting/qregion.cpp
index 5bfe681e73..d104f9ff5a 100644
--- a/src/gui/painting/qregion.cpp
+++ b/src/gui/painting/qregion.cpp
@@ -210,6 +210,16 @@ QT_BEGIN_NAMESPACE
 */
 
 /*!
+    \fn QRegion::QRegion(QRegion &&other)
+    \since 5.7
+
+    Move-constructs a new region from region \a other.
+    After the call, \a other is null.
+
+    \sa isNull()
+*/
+
+/*!
     \fn QRegion::QRegion(const QBitmap &bm)
 
     Constructs a region from the bitmap \a bm.
diff --git a/src/gui/painting/qregion.h b/src/gui/painting/qregion.h
index 94e2db2648..d66f80fcde 100644
--- a/src/gui/painting/qregion.h
+++ b/src/gui/painting/qregion.h
@@ -68,6 +68,8 @@ public:
     QRegion(const QRect &r, RegionType t = Rectangle);
     QRegion(const QPolygon &pa, Qt::FillRule fillRule = Qt::OddEvenFill);
     QRegion(const QRegion &region);
+    QRegion(QRegion &&other) Q_DECL_NOTHROW
+        : d(other.d) { other.d = const_cast<QRegionData*>(&shared_empty); }
     QRegion(const QBitmap &bitmap);
     ~QRegion();
     QRegion &operator=(const QRegion &);