QPointerUniqueId: make fit for release

- Declare as Q_MOVABLE_TYPE
- Prevent QList<QPointerUniqueId> from being instantiated
  (use QVector instead)
- Add equality relational operators
- Add qHash() overload
- Replace non-default ctor with named ctor.
- Add Q_DECL_NOTHROW.
- Add Q_DECL_CONSTEXPR.
- Rename numeric() -> numericId().
- Update docs.

The extension vector for this class calls for additional
properties to be added later, but these are not user-
settable. It thus suffices to rely on the only data
member, a qint64, which can be reinterpreted to an index
into an array or hash with actual objects. This allows
to make the class a Trivial Type (ie. no overhead over
an int) while still supporting later extension. Cf.
QSslEllipticCurve as another example of such a class.

The extension has to maintain the following invariants,
encoded into user code by way of being used in inline
functions:

- m_numericId == -1 <=> !isValid()

This is trivial to support. An extension could not and
still cannot reinterpret the qint64 member as a d-pointer,
but a d-pointer is only necessary for user-settable
properties where updating a central private data structure
would cause too much contention.

Add a test.

Since this type is used in other modules, keep the existing
functions, but mark them as deprecated with the expectation
that these compat functions be removed before 5.8.0 final.

Task-number: QTBUG-54616
Change-Id: Ia3ede0ecaeeef4cd3ffa94a72b1050bd409713a5
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

1 files changed, 39 insertions, 0 deletions

diff --git a/tests/auto/gui/kernel/qtouchevent/tst_qtouchevent.cpp b/tests/auto/gui/kernel/qtouchevent/tst_qtouchevent.cpp
index e6fd67e3a8..02814b48e9 100644
--- a/tests/auto/gui/kernel/qtouchevent/tst_qtouchevent.cpp
+++ b/tests/auto/gui/kernel/qtouchevent/tst_qtouchevent.cpp
@@ -194,6 +194,7 @@ public:
 
 private slots:
     void cleanup();
+    void qPointerUniqueId();
     void touchDisabledByDefault();
     void touchEventAcceptedByDefault();
     void touchBeginPropagatesWhenIgnored();
@@ -224,6 +225,44 @@ void tst_QTouchEvent::cleanup()
     QVERIFY(QGuiApplication::topLevelWindows().isEmpty());
 }
 
+void tst_QTouchEvent::qPointerUniqueId()
+{
+    QPointerUniqueId id1, id2;
+
+    QCOMPARE(id1.numericId(), Q_INT64_C(-1));
+    QVERIFY(!id1.isValid());
+
+    QVERIFY(  id1 == id2);
+    QVERIFY(!(id1 != id2));
+
+    QSet<QPointerUniqueId> set; // compile test
+    set.insert(id1);
+    set.insert(id2);
+    QCOMPARE(set.size(), 1);
+
+
+    const auto id3 = QPointerUniqueId::fromNumericId(-1);
+    QCOMPARE(id3.numericId(), Q_INT64_C(-1));
+    QVERIFY(!id3.isValid());
+
+    QVERIFY(  id1 == id3);
+    QVERIFY(!(id1 != id3));
+
+    set.insert(id3);
+    QCOMPARE(set.size(), 1);
+
+
+    const auto id4 = QPointerUniqueId::fromNumericId(4);
+    QCOMPARE(id4.numericId(), Q_INT64_C(4));
+    QVERIFY(id4.isValid());
+
+    QVERIFY(  id1 != id4);
+    QVERIFY(!(id1 == id4));
+
+    set.insert(id4);
+    QCOMPARE(set.size(), 2);
+}
+
 void tst_QTouchEvent::touchDisabledByDefault()
 {
     // QWidget