diff options
| author | Marc Mutz <marc.mutz@qt.io> | 2022-12-05 11:12:55 +0100 |
|---|---|---|
| committer | Marc Mutz <marc.mutz@qt.io> | 2022-12-14 19:07:19 +0100 |
| commit | e1b76ee928beff434d220c7711ea6798318d367e (patch) | |
| tree | ed71e360161a78a2586bc8351656c2f672c09796 | |
| parent | c262a1805a062fd99abc890f58ea951da80ff0af (diff) | |
Remove the last in-tree user of qExchange() and mark all of Qt free of it
We've ported all qExchange() to std::exchange by now, across all
modules, but the one in QScopedValueRollback was left behind, because
it requires C++20's version of std::exchange (constexpr).
Since q20::exchange was not approved, replace the qExchange() here
with two moves and add a comment to port to std::exchange() once we
can depend on C++20.
Then add QT_NO_QEXCHANGE to avoid new uses from creeping in.
Change-Id: I488e252433e78fb2766639dbe77a22a55196cfd1
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
| -rw-r--r-- | cmake/QtInternalTargets.cmake | 1 | ||||
| -rw-r--r-- | src/corelib/global/qttypetraits.h | 4 | ||||
| -rw-r--r-- | src/corelib/tools/qscopedvaluerollback.h | 3 |
3 files changed, 7 insertions, 1 deletions
diff --git a/cmake/QtInternalTargets.cmake b/cmake/QtInternalTargets.cmake index dc45b57eec..8de5f8a080 100644 --- a/cmake/QtInternalTargets.cmake +++ b/cmake/QtInternalTargets.cmake @@ -151,6 +151,7 @@ qt_internal_add_target_aliases(PlatformToolInternal) target_link_libraries(PlatformToolInternal INTERFACE PlatformAppInternal) qt_internal_add_global_definition(QT_NO_JAVA_STYLE_ITERATORS) +qt_internal_add_global_definition(QT_NO_QEXCHANGE) qt_internal_add_global_definition(QT_NO_NARROWING_CONVERSIONS_IN_CONNECT) qt_internal_add_global_definition(QT_EXPLICIT_QFILE_CONSTRUCTION_FROM_PATH) diff --git a/src/corelib/global/qttypetraits.h b/src/corelib/global/qttypetraits.h index 7e991ab8ca..a7bb4e5353 100644 --- a/src/corelib/global/qttypetraits.h +++ b/src/corelib/global/qttypetraits.h @@ -34,6 +34,8 @@ void qAsConst(const T &&) = delete; #endif // QT_NO_AS_CONST +#ifndef QT_NO_QEXCHANGE + // like std::exchange template <typename T, typename U = T> constexpr T qExchange(T &t, U &&newValue) @@ -45,6 +47,8 @@ noexcept(std::conjunction_v<std::is_nothrow_move_constructible<T>, return old; } +#endif // QT_NO_QEXCHANGE + namespace QtPrivate { // helper to be used to trigger a "dependent static_assert(false)" // (for instance, in a final `else` branch of a `if constexpr`.) diff --git a/src/corelib/tools/qscopedvaluerollback.h b/src/corelib/tools/qscopedvaluerollback.h index a4a451b0c7..53a31e4675 100644 --- a/src/corelib/tools/qscopedvaluerollback.h +++ b/src/corelib/tools/qscopedvaluerollback.h @@ -18,8 +18,9 @@ public: } explicit constexpr QScopedValueRollback(T &var, T value) - : varRef(var), oldValue(qExchange(var, std::move(value))) + : varRef(var), oldValue(std::move(var)) // ### C++20: std::exchange(var, std::move(value)) { + var = std::move(value); } #if __cpp_constexpr >= 201907L |