Replace qExchange calls with std::exchange

qExchange is one of the few remaining functionalities that have not been
moved out of qglobal. Given that std::exchange exists in the standard, we
can simply move to it everywhere...

...if it weren't for the fact that std::exchange is only constexpr in
C++20, and only has its noexceptness specified in (most likely) C++23.
Still, we want to move to the existing std functionality where
possible, to allow the removal of qglobal includes in lieu of something
more fine-grained in the future.
So leave any constexpr calls[1] alone for now (and observe that none of
our current usages cares about the conditional noexceptness), but
replace everything else.

[1] QScopedValueRollback' ctor and QExplicitlySharedDataPointerV2::take

Task-number: QTBUG-99313
Change-Id: I599cb9846cf319c7ffd3457130938347a75aad25
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

5 files changed, 13 insertions, 13 deletions

diff --git a/src/corelib/tools/qhash.h b/src/corelib/tools/qhash.h
index 5075459531..9f06b5d36e 100644
--- a/src/corelib/tools/qhash.h
+++ b/src/corelib/tools/qhash.h
@@ -172,7 +172,7 @@ struct MultiNode
 
     MultiNode(MultiNode &&other)
         : key(other.key),
-          value(qExchange(other.value, nullptr))
+          value(std::exchange(other.value, nullptr))
     {
     }
 
@@ -203,7 +203,7 @@ struct MultiNode
     void insertMulti(Args &&... args)
     {
         Chain *e = new Chain{ T(std::forward<Args>(args)...), nullptr };
-        e->next = qExchange(value, e);
+        e->next = std::exchange(value, e);
     }
     template<typename ...Args>
     void emplaceValue(Args &&... args)
@@ -1412,8 +1412,8 @@ public:
         return *this;
     }
     QMultiHash(QMultiHash &&other) noexcept
-        : d(qExchange(other.d, nullptr)),
-          m_size(qExchange(other.m_size, 0))
+        : d(std::exchange(other.d, nullptr)),
+          m_size(std::exchange(other.m_size, 0))
     {
     }
     QMultiHash &operator=(QMultiHash &&other) noexcept(std::is_nothrow_destructible<Node>::value)
diff --git a/src/corelib/tools/qscopedpointer.h b/src/corelib/tools/qscopedpointer.h
index 1ad7acb0f4..1637bb40a5 100644
--- a/src/corelib/tools/qscopedpointer.h
+++ b/src/corelib/tools/qscopedpointer.h
@@ -120,7 +120,7 @@ public:
     {
         if (d == other)
             return;
-        T *oldD = qExchange(d, other);
+        T *oldD = std::exchange(d, other);
         Cleanup::cleanup(oldD);
     }
 
@@ -128,7 +128,7 @@ public:
     QT_DEPRECATED_VERSION_X_6_1("Use std::unique_ptr instead, and call release().")
     T *take() noexcept
     {
-        T *oldD = qExchange(d, nullptr);
+        T *oldD = std::exchange(d, nullptr);
         return oldD;
     }
 #endif
diff --git a/src/corelib/tools/qscopeguard.h b/src/corelib/tools/qscopeguard.h
index 2639b41222..5bd202ce33 100644
--- a/src/corelib/tools/qscopeguard.h
+++ b/src/corelib/tools/qscopeguard.h
@@ -28,7 +28,7 @@ public:
 
     QScopeGuard(QScopeGuard &&other) noexcept
         : m_func(std::move(other.m_func))
-        , m_invoke(qExchange(other.m_invoke, false))
+        , m_invoke(std::exchange(other.m_invoke, false))
     {
     }
 
diff --git a/src/corelib/tools/qshareddata.h b/src/corelib/tools/qshareddata.h
index be848e2ef8..813e9d6c7a 100644
--- a/src/corelib/tools/qshareddata.h
+++ b/src/corelib/tools/qshareddata.h
@@ -66,7 +66,7 @@ public:
         if (ptr != d) {
             if (ptr)
                 ptr->ref.ref();
-            T *old = qExchange(d, ptr);
+            T *old = std::exchange(d, ptr);
             if (old && !old->ref.deref())
                 delete old;
         }
@@ -82,7 +82,7 @@ public:
         reset(o);
         return *this;
     }
-    QSharedDataPointer(QSharedDataPointer &&o) noexcept : d(qExchange(o.d, nullptr)) {}
+    QSharedDataPointer(QSharedDataPointer &&o) noexcept : d(std::exchange(o.d, nullptr)) {}
     QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_MOVE_AND_SWAP(QSharedDataPointer)
 
     operator bool () const noexcept { return d != nullptr; }
@@ -135,7 +135,7 @@ public:
     T *data() const noexcept { return d; }
     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); }
 
     void detach() { if (d && d->ref.loadRelaxed() != 1) detach_helper(); }
 
@@ -163,7 +163,7 @@ public:
         if (ptr != d) {
             if (ptr)
                 ptr->ref.ref();
-            T *old = qExchange(d, ptr);
+            T *old = std::exchange(d, ptr);
             if (old && !old->ref.deref())
                 delete old;
         }
@@ -179,7 +179,7 @@ public:
         reset(o);
         return *this;
     }
-    QExplicitlySharedDataPointer(QExplicitlySharedDataPointer &&o) noexcept : d(qExchange(o.d, nullptr)) {}
+    QExplicitlySharedDataPointer(QExplicitlySharedDataPointer &&o) noexcept : d(std::exchange(o.d, nullptr)) {}
     QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_MOVE_AND_SWAP(QExplicitlySharedDataPointer)
 
     operator bool () const noexcept { return d != nullptr; }
diff --git a/src/corelib/tools/qshareddata_impl.h b/src/corelib/tools/qshareddata_impl.h
index 61a9d1d105..a0216397cc 100644
--- a/src/corelib/tools/qshareddata_impl.h
+++ b/src/corelib/tools/qshareddata_impl.h
@@ -51,7 +51,7 @@ public:
     }
 
     QExplicitlySharedDataPointerV2(QExplicitlySharedDataPointerV2 &&other) noexcept
-        : d(qExchange(other.d, nullptr))
+        : d(std::exchange(other.d, nullptr))
     {
     }