Reimplement qSwap and Q_DECLARE_SHARED differently.

This enables the use of Q_DECLARE_SHARED with d-pointers that are
QExplicitlySharedDataPointer<PrivateClass>.

Also, this enables swapping atomically QSharedPointers.

Reviewed-by: Harald Fernengel

6 files changed, 92 insertions, 41 deletions

diff --git a/src/corelib/global/qglobal.h b/src/corelib/global/qglobal.h
index 5a2c329c6a..92fe649ff6 100644
--- a/src/corelib/global/qglobal.h
+++ b/src/corelib/global/qglobal.h
@@ -1906,6 +1906,14 @@ public: \
     static inline const char *name() { return #TYPE; } \
 }
 
+template <typename T>
+inline void qSwap(T &value1, T &value2)
+{
+    const T t = value1;
+    value1 = value2;
+    value2 = t;
+}
+
 /*
    Specialize a shared type with:
 
@@ -1915,33 +1923,12 @@ public: \
    types must declare a 'bool isDetached(void) const;' member for this
    to work.
 */
-#if defined Q_CC_MSVC && _MSC_VER < 1300
-template <typename T>
-inline void qSwap_helper(T &value1, T &value2, T*)
-{
-    T t = value1;
-    value1 = value2;
-    value2 = t;
-}
 #define Q_DECLARE_SHARED(TYPE)                                          \
 template <> inline bool qIsDetached<TYPE>(TYPE &t) { return t.isDetached(); } \
-template <> inline void qSwap_helper<TYPE>(TYPE &value1, TYPE &value2, TYPE*) \
-{ \
-    const TYPE::DataPtr t = value1.data_ptr(); \
-    value1.data_ptr() = value2.data_ptr(); \
-    value2.data_ptr() = t; \
-}
-#else
-#define Q_DECLARE_SHARED(TYPE)                                          \
-template <> inline bool qIsDetached<TYPE>(TYPE &t) { return t.isDetached(); } \
-template <typename T> inline void qSwap(T &, T &); \
 template <> inline void qSwap<TYPE>(TYPE &value1, TYPE &value2) \
 { \
-    const TYPE::DataPtr t = value1.data_ptr(); \
-    value1.data_ptr() = value2.data_ptr(); \
-    value2.data_ptr() = t; \
+    qSwap<TYPE::DataPtr>(value1.data_ptr(), value2.data_ptr()); \
 }
-#endif
 
 /*
    QTypeInfo primitive specializations
diff --git a/src/corelib/tools/qalgorithms.h b/src/corelib/tools/qalgorithms.h
index 6f623d9c7b..3e5c3cc4a8 100644
--- a/src/corelib/tools/qalgorithms.h
+++ b/src/corelib/tools/qalgorithms.h
@@ -141,23 +141,6 @@ inline void qCount(const Container &container, const T &value, Size &n)
     qCount(container.constBegin(), container.constEnd(), value, n);
 }
 
-
-#if defined Q_CC_MSVC && _MSC_VER < 1300
-template <typename T>
-inline void qSwap(T &value1, T &value2)
-{
-    qSwap_helper<T>(value1, value2, (T *)0);
-}
-#else
-template <typename T>
-inline void qSwap(T &value1, T &value2)
-{
-    T t = value1;
-    value1 = value2;
-    value2 = t;
-}
-#endif
-
 #ifdef qdoc
 template <typename T>
 LessThan qLess()
diff --git a/src/corelib/tools/qshareddata.h b/src/corelib/tools/qshareddata.h
index e13e37cd34..dde6e88c88 100644
--- a/src/corelib/tools/qshareddata.h
+++ b/src/corelib/tools/qshareddata.h
@@ -111,6 +111,9 @@ public:
 
     inline bool operator!() const { return !d; }
 
+    inline void swap(QSharedDataPointer &other)
+    { qSwap(d, other.d); }
+
 protected:
     T *clone();
 
@@ -186,6 +189,9 @@ public:
 
     inline bool operator!() const { return !d; }
 
+    inline void swap(QExplicitlySharedDataPointer &other)
+    { qSwap(d, other.d); }
+
 protected:
     T *clone();
 
@@ -235,6 +241,14 @@ template <class T>
 Q_INLINE_TEMPLATE QExplicitlySharedDataPointer<T>::QExplicitlySharedDataPointer(T *adata) : d(adata)
 { if (d) d->ref.ref(); }
 
+template <class T>
+Q_INLINE_TEMPLATE void qSwap(QSharedDataPointer<T> &p1, QSharedDataPointer<T> &p2)
+{ p1.swap(p2); }
+
+template <class T>
+Q_INLINE_TEMPLATE void qSwap(QExplicitlySharedDataPointer<T> &p1, QExplicitlySharedDataPointer<T> &p2)
+{ p1.swap(p2); }
+
 QT_END_NAMESPACE
 
 QT_END_HEADER
diff --git a/src/corelib/tools/qsharedpointer_impl.h b/src/corelib/tools/qsharedpointer_impl.h
index cbeb79ff3c..1136aa9fa2 100644
--- a/src/corelib/tools/qsharedpointer_impl.h
+++ b/src/corelib/tools/qsharedpointer_impl.h
@@ -171,8 +171,8 @@ namespace QtSharedPointer {
 
         inline ExternalRefCountData()
         {
-            QBasicAtomicInt proto = Q_BASIC_ATOMIC_INITIALIZER(1);
-            weakref = strongref = proto;
+            strongref = 1;
+            weakref = 1;
         }
         inline ExternalRefCountData(Qt::Initialization) { }
         virtual inline ~ExternalRefCountData() { Q_ASSERT(!weakref); Q_ASSERT(strongref <= 0); }
@@ -385,6 +385,12 @@ namespace QtSharedPointer {
                 delete this->value;
         }
 
+        inline void internalSwap(ExternalRefCount &other)
+        {
+            qSwap(d, other.d);
+            qSwap(this->value, other.value);
+        }
+
 #if defined(Q_NO_TEMPLATE_FRIENDS)
     public:
 #else
@@ -465,6 +471,9 @@ public:
     inline QSharedPointer<T> &operator=(const QWeakPointer<X> &other)
     { internalSet(other.d, other.value); return *this; }
 
+    inline void swap(QSharedPointer &other)
+    { internalSwap(other); }
+
     template <class X>
     QSharedPointer<X> staticCast() const
     {
@@ -682,6 +691,12 @@ Q_INLINE_TEMPLATE QWeakPointer<T> QSharedPointer<T>::toWeakRef() const
     return QWeakPointer<T>(*this);
 }
 
+template <class T>
+inline void qSwap(QSharedPointer<T> &p1, QSharedPointer<T> &p2)
+{
+    p1.swap(p2);
+}
+
 namespace QtSharedPointer {
 // helper functions:
     template <class X, class T>
diff --git a/tests/auto/qexplicitlyshareddatapointer/tst_qexplicitlyshareddatapointer.cpp b/tests/auto/qexplicitlyshareddatapointer/tst_qexplicitlyshareddatapointer.cpp
index 4cdeb5c3b7..97e57f1716 100644
--- a/tests/auto/qexplicitlyshareddatapointer/tst_qexplicitlyshareddatapointer.cpp
+++ b/tests/auto/qexplicitlyshareddatapointer/tst_qexplicitlyshareddatapointer.cpp
@@ -61,6 +61,7 @@ private Q_SLOTS:
     void clone() const;
     void data() const;
     void reset() const;
+    void swap() const;
 };
 
 class MyClass : public QSharedData
@@ -233,6 +234,25 @@ void tst_QExplicitlySharedDataPointer::reset() const
     }
 }
 
+void tst_QExplicitlySharedDataPointer::swap() const
+{
+    QExplicitlySharedDataPointer<MyClass> p1(0), p2(new MyClass());
+    QVERIFY(!p1.data());
+    QVERIFY(p2.data());
+
+    p1.swap(p2);
+    QVERIFY(p1.data());
+    QVERIFY(!p2.data());
+
+    p1.swap(p2);
+    QVERIFY(!p1.data());
+    QVERIFY(p2.data());
+
+    qSwap(p1, p2);
+    QVERIFY(p1.data());
+    QVERIFY(!p2.data());
+}
+
 QTEST_MAIN(tst_QExplicitlySharedDataPointer)
 
 #include "tst_qexplicitlyshareddatapointer.moc"
diff --git a/tests/auto/qsharedpointer/tst_qsharedpointer.cpp b/tests/auto/qsharedpointer/tst_qsharedpointer.cpp
index 58e5401bea..ab75c910b8 100644
--- a/tests/auto/qsharedpointer/tst_qsharedpointer.cpp
+++ b/tests/auto/qsharedpointer/tst_qsharedpointer.cpp
@@ -62,6 +62,7 @@ class tst_QSharedPointer: public QObject
 private slots:
     void basics_data();
     void basics();
+    void swap();
     void forwardDeclaration1();
     void forwardDeclaration2();
     void memoryManagement();
@@ -263,6 +264,37 @@ void tst_QSharedPointer::basics()
     // aData is deleted here
 }
 
+void tst_QSharedPointer::swap()
+{
+    QSharedPointer<int> p1, p2(new int(42)), control = p2;
+    QVERIFY(p1 != control);
+    QVERIFY(p1.isNull());
+    QVERIFY(p2 == control);
+    QVERIFY(!p2.isNull());
+    QVERIFY(*p2 == 42);
+
+    p1.swap(p2);
+    QVERIFY(p1 == control);
+    QVERIFY(!p1.isNull());
+    QVERIFY(p2 != control);
+    QVERIFY(p2.isNull());
+    QVERIFY(*p1 == 42);
+
+    p1.swap(p2);
+    QVERIFY(p1 != control);
+    QVERIFY(p1.isNull());
+    QVERIFY(p2 == control);
+    QVERIFY(!p2.isNull());
+    QVERIFY(*p2 == 42);
+
+    qSwap(p1, p2);
+    QVERIFY(p1 == control);
+    QVERIFY(!p1.isNull());
+    QVERIFY(p2 != control);
+    QVERIFY(p2.isNull());
+    QVERIFY(*p1 == 42);
+}
+
 class ForwardDeclared;
 ForwardDeclared *forwardPointer();
 void externalForwardDeclaration();