QFutureInterface(Base): code tidies

refT()/derefT() can be marked noexcept; we don't care about not
overflowing the refcounter as a precondition. (This is BC, as no
compiler mangles noexcept.) This in turn allows to mark a constructor
calling refT() as noexcept.

Driveby: mark also the same functions to not be `const` in Qt 7.
They clearly are meant to modify *this, and constness only works
because of the unmanaged (raw) d-pointer.

Change-Id: I8d7d365640ff2e1cedc0a234c9abccdfc95ba6e3
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Andrei Golubev <andrei.golubev@qt.io>
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>

2 files changed, 6 insertions, 5 deletions

diff --git a/src/corelib/thread/qfutureinterface.cpp b/src/corelib/thread/qfutureinterface.cpp
index 8906245191..9bb7d505e2 100644
--- a/src/corelib/thread/qfutureinterface.cpp
+++ b/src/corelib/thread/qfutureinterface.cpp
@@ -586,12 +586,12 @@ void QFutureInterfaceBase::swap(QFutureInterfaceBase &other) noexcept
     qSwap(d, other.d);
 }
 
-bool QFutureInterfaceBase::refT() const
+bool QFutureInterfaceBase::refT() const noexcept
 {
     return d->refCount.refT();
 }
 
-bool QFutureInterfaceBase::derefT() const
+bool QFutureInterfaceBase::derefT() const noexcept
 {
     // Called from ~QFutureInterface
     return !d || d->refCount.derefT();
diff --git a/src/corelib/thread/qfutureinterface.h b/src/corelib/thread/qfutureinterface.h
index 6df15304fc..3a6fe86d76 100644
--- a/src/corelib/thread/qfutureinterface.h
+++ b/src/corelib/thread/qfutureinterface.h
@@ -178,8 +178,9 @@ public:
     void swap(QFutureInterfaceBase &other) noexcept;
 
 protected:
-    bool refT() const;
-    bool derefT() const;
+    // ### Qt 7: remove const from refT/derefT
+    bool refT() const noexcept;
+    bool derefT() const noexcept;
     void reset();
     void rethrowPossibleException();
 public:
@@ -234,7 +235,7 @@ public:
         refT();
     }
     QFutureInterface(const QFutureInterfaceBase &dd) : QFutureInterfaceBase(dd) { refT(); }
-    QFutureInterface(QFutureInterfaceBase &&dd) : QFutureInterfaceBase(std::move(dd)) { refT(); }
+    QFutureInterface(QFutureInterfaceBase &&dd) noexcept : QFutureInterfaceBase(std::move(dd)) { refT(); }
     QFutureInterface &operator=(const QFutureInterface &other)
     {
         QFutureInterface copy(other);