Implement move-ctor and move-assignment-op for QScopedPointer

It makes sense for a QScopedPointer to be movable, for instance
for allowing instances to be returned from a function.
Ownwership of the managed pointer is still tied to one (and one only)
QScopedPointer instance.

Moreover, a move assignment operator makes sense as well, as it
implementing the equivalent of

  this->reset(other.take());

only when other is a rvalue and not a lvalue (so either it's a temporary
or it's getting explicitly moved in with std::move).

This makes QScopedPointer API's a bit closer to std::unique_ptr's one.

Task-number: QTBUG-29754
Change-Id: If1ac0c688327a67af4ad5b7ad45b439b022ed1c6
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

2 files changed, 40 insertions, 0 deletions

diff --git a/src/corelib/tools/qscopedpointer.cpp b/src/corelib/tools/qscopedpointer.cpp
index 0848754de5..cf2f9bee0c 100644
--- a/src/corelib/tools/qscopedpointer.cpp
+++ b/src/corelib/tools/qscopedpointer.cpp
@@ -130,6 +130,33 @@ QT_BEGIN_NAMESPACE
     Constructs this QScopedPointer instance and sets its pointer to \a p.
 */
 
+#ifndef Q_QDOC // QTBUG-32675, qdoc can't parse rvalue refs
+/*!
+    \fn QScopedPointer::QScopedPointer(QScopedPointer<T, Cleanup> &&other)
+
+    Move-constructs a QScopedPointer instance, making it point at the same
+    object that \a other was pointing to. \a other is reset to point to \c{NULL}.
+
+    \since 5.2
+*/
+
+/*!
+    \fn QScopedPointer<T, Cleanup> &operator=(QScopedPointer<T, Cleanup> &&other)
+
+    Move-assigns \a other to this QScopedPointer instance, transferring the
+    ownership of the managed pointer to this instance.
+
+    If \a other and this instance are actually the same object, this operator
+    does nothing.
+
+    Otherwise, this instance is set to point to the object \a other
+    is pointing to, and \a other is set to point to \c{NULL}.
+    If this instance was pointing to an object, that object is destroyed,
+
+    \since 5.2
+*/
+#endif
+
 /*!
     \fn QScopedPointer::~QScopedPointer()
 
diff --git a/src/corelib/tools/qscopedpointer.h b/src/corelib/tools/qscopedpointer.h
index 2155c56e27..c4a148c4e4 100644
--- a/src/corelib/tools/qscopedpointer.h
+++ b/src/corelib/tools/qscopedpointer.h
@@ -98,6 +98,19 @@ public:
         Cleanup::cleanup(oldD);
     }
 
+#ifdef Q_COMPILER_RVALUE_REFS
+    inline QScopedPointer(QScopedPointer<T, Cleanup> &&other)
+        : d(other.take())
+    {
+    }
+
+    inline QScopedPointer<T, Cleanup> &operator=(QScopedPointer<T, Cleanup> &&other)
+    {
+        reset(other.take());
+        return *this;
+    }
+#endif
+
     inline T &operator*() const
     {
         Q_ASSERT(d);