QPen: add move constructor

After this change, the relation between copy/move constructor calls in QtGui is
something like 40/16.

A moved-from QPen can only be copied, assigned-to or else destroyed. This required
adding a nullptr check to the copy ctor and the dtor and rewriting copy assignment
(which used non-nullptr-safe qAtomicAssign) in terms of copy construction and
swapping.

Extensive tests included. They are implemented such that they work in C++98 as well
as C++11 mode, but they naturally test move semantics only in a C++11 build.

Change-Id: If68f37c10b8eeefb2478cbae386cd2e38b4f6e19
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 53 insertions, 0 deletions

diff --git a/tests/auto/gui/painting/qpen/tst_qpen.cpp b/tests/auto/gui/painting/qpen/tst_qpen.cpp
index 07c996d026..a373c51710 100644
--- a/tests/auto/gui/painting/qpen/tst_qpen.cpp
+++ b/tests/auto/gui/painting/qpen/tst_qpen.cpp
@@ -57,6 +57,8 @@ public:
 private slots:
     void getSetCheck();
     void swap();
+    void move();
+    void move_assign();
     void operator_eq_eq();
     void operator_eq_eq_data();
 
@@ -101,6 +103,57 @@ void tst_QPen::swap()
     QCOMPARE(p2.color(), QColor(Qt::black));
 }
 
+void tst_QPen::move()
+{
+    QPen p1(Qt::black);
+
+    // check that moving does the right thing:
+    QPen p2 = qMove(p1); // could be move or copy construction, so don't check p1's state
+    QCOMPARE(p2.color(), QColor(Qt::black));
+
+    // this, executed ehre, would crash:
+    // QVERIFY(p1.style() != Qt::NoPen);
+
+    // check that moved-from QPen p1 can still be safely copied:
+    const QPen p3 = p1;
+
+    // check that moved-from QPen p1 can still be safely assigned to:
+    const QPen p4(Qt::yellow);
+    p1 = p4;
+    QCOMPARE(p1.color(), QColor(Qt::yellow));
+
+    // check that moved-from QPens p2, p3 can still be safely destroyed:
+    QPen p5 = qMove(p2);
+
+    // intentionally no more statements beyond this point
+}
+
+void tst_QPen::move_assign()
+{
+    QPen p1(Qt::black), p2(Qt::white);
+
+    // check that moving does the right thing:
+    p2 = qMove(p1); // could be move or copy assignment, so don't check p1's state
+    QCOMPARE(p2.color(), QColor(Qt::black));
+
+    // check that move-assigned-from QPen p1 can still be used, albeit
+    // with undocumented state (it's p2's original state):
+    QVERIFY(p1.style() != Qt::NoPen);
+
+    // check that moved-from QPen p1 can still be safely copied:
+    const QPen p3 = p1;
+
+    // check that moved-from QPen p1 can still be safely assigned to:
+    const QPen p4(Qt::yellow);
+    p1 = p4;
+    QCOMPARE(p1.color(), QColor(Qt::yellow));
+
+    // check that moved-from QPens p2, p3 can still be safely destroyed:
+    QPen p5;
+    p5 = qMove(p2);
+
+    // intentionally no more statements beyond this point
+}
 
 tst_QPen::tst_QPen()