Deprecate setSharable in Qt containers

The ability to set a container to be unsharable has very little use and
it costs us an extra conditional for every refcount up and possibly
down.

This change is a no-op for current Qt 5. It shuffles a few things around
just so Qt can compile if you define QT_NO_UNSHARABLE_CONTAINERS. That
is done to ease the fixing of the code in Qt 6 and to make my life
easier: I'll keep that defined in my local Qt build so I can catch any
misuses of this deprecated API.

The newly deprecated methods are not marked QT_DEPRECATED because the
bootstrapped tools wouldn't build -- they're built with QT_NO_DEPRECATED
defined, which causes build errors.

[ChangeLog][QtCore] The setSharable() and isSharable() functions in Qt
containers has been deprecated and will be removed in Qt 6. New
applications should not use this feature, while old applications that
may be using this (undocumented) feature should port away from it.

Discussed-on: http://lists.qt-project.org/pipermail/development/2014-February/015724.html
Change-Id: I789771743dcaed6a43eccd99382f8b3ffa61e479
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

2 files changed, 40 insertions, 7 deletions

diff --git a/tests/auto/corelib/tools/qarraydata/simplevector.h b/tests/auto/corelib/tools/qarraydata/simplevector.h
index 40917c0172..af0ced130c 100644
--- a/tests/auto/corelib/tools/qarraydata/simplevector.h
+++ b/tests/auto/corelib/tools/qarraydata/simplevector.h
@@ -101,9 +101,10 @@ public:
     bool isStatic() const { return d->ref.isStatic(); }
     bool isShared() const { return d->ref.isShared(); }
     bool isSharedWith(const SimpleVector &other) const { return d == other.d; }
+#if QT_SUPPORTS(UNSHARABLE_CONTAINERS)
     bool isSharable() const { return d->ref.isSharable(); }
-
     void setSharable(bool sharable) { d.setSharable(sharable); }
+#endif
 
     size_t size() const { return d->size; }
     size_t capacity() const { return d->alloc; }
diff --git a/tests/auto/corelib/tools/qarraydata/tst_qarraydata.cpp b/tests/auto/corelib/tools/qarraydata/tst_qarraydata.cpp
index 60b807a7bc..35ec0ef019 100644
--- a/tests/auto/corelib/tools/qarraydata/tst_qarraydata.cpp
+++ b/tests/auto/corelib/tools/qarraydata/tst_qarraydata.cpp
@@ -52,7 +52,9 @@ struct SharedNullVerifier
     {
         Q_ASSERT(QArrayData::shared_null[0].ref.isStatic());
         Q_ASSERT(QArrayData::shared_null[0].ref.isShared());
+#if QT_SUPPORTS(UNSHARABLE_CONTAINERS)
         Q_ASSERT(QArrayData::shared_null[0].ref.isSharable());
+#endif
     }
 };
 
@@ -107,7 +109,9 @@ void tst_QArrayData::referenceCounting()
         QCOMPARE(array.ref.atomic.load(), 1);
 
         QVERIFY(!array.ref.isStatic());
+#if QT_SUPPORTS(UNSHARABLE_CONTAINERS)
         QVERIFY(array.ref.isSharable());
+#endif
 
         QVERIFY(array.ref.ref());
         QCOMPARE(array.ref.atomic.load(), 2);
@@ -127,6 +131,7 @@ void tst_QArrayData::referenceCounting()
         // Now would be a good time to free/release allocated data
     }
 
+#if QT_SUPPORTS(UNSHARABLE_CONTAINERS)
     {
         // Reference counting initialized to 0 (non-sharable)
         QArrayData array = { { Q_BASIC_ATOMIC_INITIALIZER(0) }, 0, 0, 0, 0 };
@@ -145,6 +150,7 @@ void tst_QArrayData::referenceCounting()
 
         // Free/release data
     }
+#endif
 
     {
         // Reference counting initialized to -1 (static read-only data)
@@ -153,13 +159,16 @@ void tst_QArrayData::referenceCounting()
         QCOMPARE(array.ref.atomic.load(), -1);
 
         QVERIFY(array.ref.isStatic());
+#if QT_SUPPORTS(UNSHARABLE_CONTAINERS)
         QVERIFY(array.ref.isSharable());
+#endif
 
         QVERIFY(array.ref.ref());
         QCOMPARE(array.ref.atomic.load(), -1);
 
         QVERIFY(array.ref.deref());
         QCOMPARE(array.ref.atomic.load(), -1);
+
     }
 }
 
@@ -169,16 +178,19 @@ void tst_QArrayData::sharedNullEmpty()
     QArrayData *empty = QArrayData::allocate(1, Q_ALIGNOF(QArrayData), 0);
 
     QVERIFY(null->ref.isStatic());
-    QVERIFY(null->ref.isSharable());
     QVERIFY(null->ref.isShared());
 
     QVERIFY(empty->ref.isStatic());
-    QVERIFY(empty->ref.isSharable());
     QVERIFY(empty->ref.isShared());
 
     QCOMPARE(null->ref.atomic.load(), -1);
     QCOMPARE(empty->ref.atomic.load(), -1);
 
+#if QT_SUPPORTS(UNSHARABLE_CONTAINERS)
+    QVERIFY(null->ref.isSharable());
+    QVERIFY(empty->ref.isSharable());
+#endif
+
     QVERIFY(null->ref.ref());
     QVERIFY(empty->ref.ref());
 
@@ -305,6 +317,7 @@ void tst_QArrayData::simpleVector()
     QVERIFY(!v7.isShared());
     QVERIFY(!v8.isShared());
 
+#if QT_SUPPORTS(UNSHARABLE_CONTAINERS)
     QVERIFY(v1.isSharable());
     QVERIFY(v2.isSharable());
     QVERIFY(v3.isSharable());
@@ -313,6 +326,7 @@ void tst_QArrayData::simpleVector()
     QVERIFY(v6.isSharable());
     QVERIFY(v7.isSharable());
     QVERIFY(v8.isSharable());
+#endif
 
     QVERIFY(v1.isSharedWith(v2));
     QVERIFY(v1.isSharedWith(v3));
@@ -496,6 +510,7 @@ void tst_QArrayData::simpleVector()
     for (int i = 0; i < 120; ++i)
         QCOMPARE(v1[i], v8[i % 10]);
 
+#if QT_SUPPORTS(UNSHARABLE_CONTAINERS)
     {
         v7.setSharable(true);
         QVERIFY(v7.isSharable());
@@ -558,6 +573,7 @@ void tst_QArrayData::simpleVector()
         QVERIFY(null.isEmpty());
         QVERIFY(empty.isEmpty());
     }
+#endif
 }
 
 Q_DECLARE_METATYPE(SimpleVector<int>)
@@ -648,7 +664,7 @@ void tst_QArrayData::allocate_data()
     QTest::addColumn<size_t>("alignment");
     QTest::addColumn<QArrayData::AllocationOptions>("allocateOptions");
     QTest::addColumn<bool>("isCapacityReserved");
-    QTest::addColumn<bool>("isSharable");
+    QTest::addColumn<bool>("isSharable");       // ### Qt6: remove
     QTest::addColumn<const QArrayData *>("commonEmpty");
 
     struct {
@@ -662,10 +678,12 @@ void tst_QArrayData::allocate_data()
     };
 
     QArrayData *shared_empty = QArrayData::allocate(0, Q_ALIGNOF(QArrayData), 0);
-    QArrayData *unsharable_empty = QArrayData::allocate(0, Q_ALIGNOF(QArrayData), 0, QArrayData::Unsharable);
-
     QVERIFY(shared_empty);
+
+#if QT_SUPPORTS(UNSHARABLE_CONTAINERS)
+    QArrayData *unsharable_empty = QArrayData::allocate(0, Q_ALIGNOF(QArrayData), 0, QArrayData::Unsharable);
     QVERIFY(unsharable_empty);
+#endif
 
     struct {
         char const *description;
@@ -676,10 +694,12 @@ void tst_QArrayData::allocate_data()
     } options[] = {
         { "Default", QArrayData::Default, false, true, shared_empty },
         { "Reserved", QArrayData::CapacityReserved, true, true, shared_empty },
+#if QT_SUPPORTS(UNSHARABLE_CONTAINERS)
         { "Reserved | Unsharable",
             QArrayData::CapacityReserved | QArrayData::Unsharable, true, false,
             unsharable_empty },
         { "Unsharable", QArrayData::Unsharable, false, false, unsharable_empty },
+#endif
         { "Grow", QArrayData::Grow, false, true, shared_empty }
     };
 
@@ -700,7 +720,6 @@ void tst_QArrayData::allocate()
     QFETCH(size_t, alignment);
     QFETCH(QArrayData::AllocationOptions, allocateOptions);
     QFETCH(bool, isCapacityReserved);
-    QFETCH(bool, isSharable);
     QFETCH(const QArrayData *, commonEmpty);
 
     // Minimum alignment that can be requested is that of QArrayData.
@@ -725,7 +744,10 @@ void tst_QArrayData::allocate()
         else
             QCOMPARE(data->alloc, uint(capacity));
         QCOMPARE(data->capacityReserved, uint(isCapacityReserved));
+#if QT_SUPPORTS(UNSHARABLE_CONTAINERS)
+        QFETCH(bool, isSharable);
         QCOMPARE(data->ref.isSharable(), isSharable);
+#endif
 
         // Check that the allocated array can be used. Best tested with a
         // memory checker, such as valgrind, running.
@@ -1302,6 +1324,7 @@ static inline bool arrayIsFilledWith(const QArrayDataPointer<int> &array,
 
 void tst_QArrayData::setSharable_data()
 {
+#if QT_SUPPORTS(UNSHARABLE_CONTAINERS)
     QTest::addColumn<QArrayDataPointer<int> >("array");
     QTest::addColumn<size_t>("size");
     QTest::addColumn<size_t>("capacity");
@@ -1342,10 +1365,12 @@ void tst_QArrayData::setSharable_data()
     QTest::newRow("non-empty-reserved") << nonEmptyReserved << size_t(7) << size_t(15) << true << 2;
     QTest::newRow("static-array") << staticArray << size_t(10) << size_t(0) << false << 3;
     QTest::newRow("raw-data") << rawData << size_t(10) << size_t(0) << false << 3;
+#endif
 }
 
 void tst_QArrayData::setSharable()
 {
+#if QT_SUPPORTS(UNSHARABLE_CONTAINERS)
     QFETCH(QArrayDataPointer<int>, array);
     QFETCH(size_t, size);
     QFETCH(size_t, capacity);
@@ -1424,6 +1449,7 @@ void tst_QArrayData::setSharable()
 
     QCOMPARE(array->ref.isShared(), !(size || isCapacityReserved));
     QVERIFY(array->ref.isSharable());
+#endif
 }
 
 struct ResetOnDtor
@@ -1474,6 +1500,7 @@ void fromRawData_impl()
         QVERIFY((const T *)raw.constBegin() != array);
     }
 
+#if QT_SUPPORTS(UNSHARABLE_CONTAINERS)
     {
         // Immutable, unsharable
         SimpleVector<T> raw = SimpleVector<T>::fromRawData(array,
@@ -1502,6 +1529,7 @@ void fromRawData_impl()
         QCOMPARE(raw.back(), T(11));
         QVERIFY((const T *)raw.constBegin() != array);
     }
+#endif
 }
 
 void tst_QArrayData::fromRawData_data()
@@ -1558,7 +1586,9 @@ void tst_QArrayData::literals()
         QVERIFY(v.isStatic());
 #endif
 
+#if QT_SUPPORTS(UNSHARABLE_CONTAINERS)
         QVERIFY(v.isSharable());
+#endif
         QCOMPARE((void*)(const char*)(v.constBegin() + v.size()), (void*)(const char*)v.constEnd());
 
         for (int i = 0; i < 10; ++i)
@@ -1607,7 +1637,9 @@ void tst_QArrayData::variadicLiterals()
 
         QVERIFY(v.isStatic());
 
+#if QT_SUPPORTS(UNSHARABLE_CONTAINERS)
         QVERIFY(v.isSharable());
+#endif
         QCOMPARE((const int *)(v.constBegin() + v.size()), (const int *)v.constEnd());
 
         for (int i = 0; i < 7; ++i)