Replace qExchange with std::exchange

None of these users require C++20 constexpr or C++23 noexcept, the
only remaining difference between std::exchange and qExchange.

This leaves a single qExchange() user, in QScopedValueRollback, that
requires the constexpr version, only available from C++20, and thus
remains unported.

Task-number: QTBUG-99313
Change-Id: Iea46f6ed61d6bd8a5b2fd9d9ec4d70c980b443a2
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

examples/network/secureudpserver/server.cpp

@@ -213,7 +213,7 @@ void DtlsServer::decryptDatagram(QDtls *connection, const QByteArray &clientMess
 //! [14]
 void DtlsServer::shutdown()
 {
-    for (const auto &connection : qExchange(knownClients, {}))
+    for (const auto &connection : std::exchange(knownClients, {}))
         connection->shutdown(&serverSocket);
 
     serverSocket.close();

src/corelib/kernel/qcore_mac_p.h

@@ -92,7 +92,7 @@ public:
     QAppleRefCounted(QAppleRefCounted &&other)
             noexcept(std::is_nothrow_move_assignable<T>::value &&
                      std::is_nothrow_move_constructible<T>::value)
-        : value(qExchange(other.value, T())) {}
+        : value(std::exchange(other.value, T())) {}
     QAppleRefCounted(const QAppleRefCounted &other) : value(other.value) { if (value) RetainFunction(value); }
     ~QAppleRefCounted() { if (value) ReleaseFunction(value); }
     operator T() const { return value; }
@@ -258,7 +258,7 @@ public:
     Q_DISABLE_COPY(QAppleLogActivity)
 
     QAppleLogActivity(QAppleLogActivity &&other)
-        : activity(qExchange(other.activity, nullptr)), state(other.state)
+        : activity(std::exchange(other.activity, nullptr)), state(other.state)
     {
     }
 
@@ -333,7 +333,7 @@ public:
 
     QMacNotificationObserver(const QMacNotificationObserver &other) = delete;
     QMacNotificationObserver(QMacNotificationObserver &&other)
-        : observer(qExchange(other.observer, nullptr))
+        : observer(std::exchange(other.observer, nullptr))
     {
     }
 

src/corelib/kernel/qwinregistry_p.h

@@ -34,7 +34,7 @@ public:
     ~QWinRegistryKey();
 
     QWinRegistryKey(QWinRegistryKey &&other) noexcept
-        : m_key(qExchange(other.m_key, nullptr)) {}
+        : m_key(std::exchange(other.m_key, nullptr)) {}
     QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_MOVE_AND_SWAP(QWinRegistryKey)
     void swap(QWinRegistryKey &other) noexcept { qSwap(m_key, other.m_key); }
 

src/corelib/tools/qduplicatetracker_p.h

@@ -56,13 +56,13 @@ class QDuplicateTracker {
         auto insert(const T &e) {
             auto it = QSet<T>::insert(e);
             const auto n = this->size();
-            return std::pair{it, qExchange(setSize, n) != n};
+            return std::pair{it, std::exchange(setSize, n) != n};
         }
 
         auto insert(T &&e) {
             auto it = QSet<T>::insert(std::move(e));
             const auto n = this->size();
-            return std::pair{it, qExchange(setSize, n) != n};
+            return std::pair{it, std::exchange(setSize, n) != n};
         }
     };
     Set set{Prealloc};

src/corelib/tools/qshareddata.h

@@ -49,7 +49,7 @@ public:
     const T *data() const noexcept { return d; }
     const T *get() const noexcept { return d; }
     const T *constData() const noexcept { return d; }
-    T *take() noexcept { return qExchange(d, nullptr); }
+    T *take() noexcept { return std::exchange(d, nullptr); }
 
     QSharedDataPointer() noexcept : d(nullptr) { }
     ~QSharedDataPointer() { if (d && !d->ref.deref()) delete d; }

src/corelib/tools/qshareddata_impl.h

@@ -92,7 +92,7 @@ public:
 
     constexpr T *take() noexcept
     {
-        return qExchange(d, nullptr);
+        return std::exchange(d, nullptr);
     }
 
     bool isShared() const noexcept

src/widgets/kernel/qwidgetrepaintmanager.cpp

@@ -988,7 +988,7 @@ void QWidgetRepaintManager::flush()
     if (!hasNeedsFlushWidgets)
         return;
 
-    for (QWidget *w : qExchange(needsFlushWidgets, {})) {
+    for (QWidget *w : std::exchange(needsFlushWidgets, {})) {
         QWidgetPrivate *wd = w->d_func();
         Q_ASSERT(wd->needsFlush);
         QPlatformTextureList *widgetTexturesForNative = wd->textureChildSeen ? widgetTexturesFor(tlw, w) : nullptr;

tests/auto/widgets/kernel/qwidget/tst_qwidget.cpp

@@ -5513,7 +5513,7 @@ public:
     }
 
     QObjectCastChecker(QObjectCastChecker &&other) noexcept
-        : m_target(qExchange(other.m_target, nullptr))
+        : m_target(std::exchange(other.m_target, nullptr))
     {}
 
     QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_MOVE_AND_SWAP(QObjectCastChecker)