QPointer: add member-swap

Change-Id: I5704badc86f98e549c586656ec8df3915632ce15
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

3 files changed, 27 insertions, 0 deletions

diff --git a/src/corelib/kernel/qpointer.cpp b/src/corelib/kernel/qpointer.cpp
index 2c872716d1..39cc17f7dd 100644
--- a/src/corelib/kernel/qpointer.cpp
+++ b/src/corelib/kernel/qpointer.cpp
@@ -128,6 +128,14 @@
 */
 
 /*!
+    \fn void QPointer::swap(QPointer<T> &other)
+    \since 5.6
+
+    Swaps the contents of this QPointer with the contents of \a other.
+    This operation is very fast and never fails.
+*/
+
+/*!
     \fn QPointer<T> & QPointer::operator=(T* p)
 
     Assignment operator. This guarded pointer will now point to the
diff --git a/src/corelib/kernel/qpointer.h b/src/corelib/kernel/qpointer.h
index 07649ce0b2..a3e922ccc9 100644
--- a/src/corelib/kernel/qpointer.h
+++ b/src/corelib/kernel/qpointer.h
@@ -66,6 +66,8 @@ public:
     // compiler-generated copy/move ctor/assignment operators are fine!
     inline ~QPointer() { }
 
+    inline void swap(QPointer &other) { wp.swap(other.wp); }
+
     inline QPointer<T> &operator=(T* p)
     { wp.assign(static_cast<QObjectType*>(p)); return *this; }
 
diff --git a/tests/auto/corelib/kernel/qpointer/tst_qpointer.cpp b/tests/auto/corelib/kernel/qpointer/tst_qpointer.cpp
index 814c4bb691..d7cce4ada4 100644
--- a/tests/auto/corelib/kernel/qpointer/tst_qpointer.cpp
+++ b/tests/auto/corelib/kernel/qpointer/tst_qpointer.cpp
@@ -50,6 +50,7 @@ private slots:
     void destructor();
     void assignment_operators();
     void equality_operators();
+    void swap();
     void isNull();
     void dereference_operators();
     void disconnect();
@@ -169,6 +170,22 @@ void tst_QPointer::equality_operators()
 #endif
 }
 
+void tst_QPointer::swap()
+{
+    QPointer<QObject> c1, c2;
+    {
+        QObject o;
+        c1 = &o;
+        QVERIFY(c2.isNull());
+        QCOMPARE(c1.data(), &o);
+        c1.swap(c2);
+        QVERIFY(c1.isNull());
+        QCOMPARE(c2.data(), &o);
+    }
+    QVERIFY(c1.isNull());
+    QVERIFY(c2.isNull());
+}
+
 void tst_QPointer::isNull()
 {
     QPointer<QObject> p1;