qSwap: use std::swap as implementation, and specialize std::swap for our container

std::swap might be reimplemented for many types. That might speedup
our Qt algorithms that uses qSwap. (std::swap also use std::move)

Specialize std::swap for our shared type, so stl algorithls work faster

Reviewed-by: Joao

4 files changed, 58 insertions, 3 deletions

diff --git a/src/corelib/global/qglobal.h b/src/corelib/global/qglobal.h
index 547ad8d..90dd43e 100644
--- a/src/corelib/global/qglobal.h
+++ b/src/corelib/global/qglobal.h
@@ -43,6 +43,9 @@
 #define QGLOBAL_H
 
 #include <stddef.h>
+#ifndef QT_NO_STL
+#include <algorithm>
+#endif
 
 #define QT_VERSION_STR   "4.8.0"
 /*
@@ -2062,9 +2065,14 @@ Q_DECLARE_TYPEINFO_BODY(TYPE, FLAGS)
 template <typename T>
 inline void qSwap(T &value1, T &value2)
 {
+#ifdef QT_NO_STL
     const T t = value1;
     value1 = value2;
     value2 = t;
+#else
+    using std::swap;
+    swap(value1, value2);
+#endif
 }
 
 /*
@@ -2076,12 +2084,23 @@ inline void qSwap(T &value1, T &value2)
    types must declare a 'bool isDetached(void) const;' member for this
    to work.
 */
+#ifdef QT_NO_STL
+#define Q_DECLARE_SHARED_STL(TYPE)
+#else
+#define Q_DECLARE_SHARED_STL(TYPE) \
+QT_END_NAMESPACE \
+namespace std { \
+    template<> inline void swap<TYPE>(TYPE &value1, TYPE &value2) \
+    { swap(value1.data_ptr(), value2.data_ptr()); } \
+} \
+QT_BEGIN_NAMESPACE
+#endif
+
 #define Q_DECLARE_SHARED(TYPE)                                          \
 template <> inline bool qIsDetached<TYPE>(TYPE &t) { return t.isDetached(); } \
 template <> inline void qSwap<TYPE>(TYPE &value1, TYPE &value2) \
-{ \
-    qSwap(value1.data_ptr(), value2.data_ptr()); \
-}
+{ qSwap(value1.data_ptr(), value2.data_ptr()); } \
+Q_DECLARE_SHARED_STL(TYPE)
 
 /*
    QTypeInfo primitive specializations
diff --git a/src/corelib/tools/qscopedpointer.h b/src/corelib/tools/qscopedpointer.h
index 40d3851..a24cc71 100644
--- a/src/corelib/tools/qscopedpointer.h
+++ b/src/corelib/tools/qscopedpointer.h
@@ -186,6 +186,18 @@ template <class T, class Cleanup>
 Q_INLINE_TEMPLATE void qSwap(QScopedPointer<T, Cleanup> &p1, QScopedPointer<T, Cleanup> &p2)
 { p1.swap(p2); }
 
+#ifndef QT_NO_STL
+QT_END_NAMESPACE
+namespace std {
+    template <class T, class Cleanup>
+    Q_INLINE_TEMPLATE void swap(QScopedPointer<T, Cleanup> &p1, QScopedPointer<T, Cleanup> &p2)
+    { p1.swap(p2); }
+}
+QT_BEGIN_NAMESPACE
+#endif
+
+
+
 namespace QtPrivate {
     template <typename X, typename Y> struct QScopedArrayEnsureSameType;
     template <typename X> struct QScopedArrayEnsureSameType<X,X> { typedef X* Type; };
diff --git a/src/corelib/tools/qshareddata.h b/src/corelib/tools/qshareddata.h
index b646a9d..1079595 100644
--- a/src/corelib/tools/qshareddata.h
+++ b/src/corelib/tools/qshareddata.h
@@ -263,6 +263,20 @@ template <class T>
 Q_INLINE_TEMPLATE void qSwap(QExplicitlySharedDataPointer<T> &p1, QExplicitlySharedDataPointer<T> &p2)
 { p1.swap(p2); }
 
+#ifndef QT_NO_STL
+QT_END_NAMESPACE
+namespace std {
+    template <class T>
+    Q_INLINE_TEMPLATE void swap(QSharedDataPointer<T> &p1, QSharedDataPointer<T> &p2)
+    { p1.swap(p2); }
+
+    template <class T>
+    Q_INLINE_TEMPLATE void swap(QExplicitlySharedDataPointer<T> &p1, QExplicitlySharedDataPointer<T> &p2)
+    { p1.swap(p2); }
+}
+QT_BEGIN_NAMESPACE
+#endif
+
 QT_END_NAMESPACE
 
 QT_END_HEADER
diff --git a/src/corelib/tools/qsharedpointer_impl.h b/src/corelib/tools/qsharedpointer_impl.h
index 4b47713..965ac14 100644
--- a/src/corelib/tools/qsharedpointer_impl.h
+++ b/src/corelib/tools/qsharedpointer_impl.h
@@ -784,6 +784,16 @@ inline void qSwap(QSharedPointer<T> &p1, QSharedPointer<T> &p2)
     p1.swap(p2);
 }
 
+#ifndef QT_NO_STL
+QT_END_NAMESPACE
+namespace std {
+    template <class T>
+    inline void swap(QSharedPointer<T> &p1, QSharedPointer<T> &p2)
+    { p1.swap(p2); }
+}
+QT_BEGIN_NAMESPACE
+#endif
+
 namespace QtSharedPointer {
 // helper functions:
     template <class X, class T>