QVariant: add missing const to QMetaTypeInterface pointers

They're ALWAYS const objects, though they also chock full of relocations
so they are never in read-only sections of memory (except maybe in final
executables that are position-dependent).

These are methods in a private sub-class of QVariant. No one outside of
QtCore (at least qtbase) should be using them directly. QVariant doesn't
have many friends (a bit anti-social); the one that matters is
qvariant_cast and that one does access QVariant::Private. This is not a
BC problem because QVariant::Private::type()'s signature is not
changing. In any case, QVariant's Q_CORE_EXPORT does not apply to
QVariant::Private anyway (see [1]).

[1] https://msvc.godbolt.org/z/r9cer8eWh

Pick-to: 6.3 6.4
Change-Id: I3859764fed084846bcb0fffd17035355f823dc8f
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
This commit is contained in:
Thiago Macieira 2022-07-19 12:58:36 -07:00
parent 48675dfa33
commit eb9ace1cee
2 changed files with 9 additions and 12 deletions

View File

@ -215,7 +215,7 @@ static qreal qConvertToRealNumber(const QVariant::Private *d, bool *ok)
// the type of d has already been set, but other field are not set
static void customConstruct(QVariant::Private *d, const void *copy)
{
QtPrivate::QMetaTypeInterface *iface = d->typeInterface();
const QtPrivate::QMetaTypeInterface *iface = d->typeInterface();
if (!(iface && iface->size)) {
*d = QVariant::Private();
return;
@ -494,11 +494,8 @@ QVariant::QVariant(const QVariant &p)
{
if (d.is_shared) {
d.data.shared->ref.ref();
return;
}
QtPrivate::QMetaTypeInterface *iface = d.typeInterface();
auto other = p.constData();
if (iface) {
} else if (const QtPrivate::QMetaTypeInterface *iface = d.typeInterface()) {
auto other = p.constData();
if (other)
iface->copyCtr(iface, &d.data, other);
else
@ -986,7 +983,7 @@ QVariant &QVariant::operator=(const QVariant &variant)
d = variant.d;
} else {
d = variant.d;
QtPrivate::QMetaTypeInterface *iface = d.typeInterface();
const QtPrivate::QMetaTypeInterface *iface = d.typeInterface();
const void *other = variant.constData();
if (iface) {
if (other)

View File

@ -428,7 +428,7 @@ public:
static constexpr size_t MaxInternalSize = 3*sizeof(void *);
template<typename T>
static constexpr bool CanUseInternalSpace = (QTypeInfo<T>::isRelocatable && sizeof(T) <= MaxInternalSize && alignof(T) <= alignof(double));
static constexpr bool canUseInternalSpace(QtPrivate::QMetaTypeInterface *type)
static constexpr bool canUseInternalSpace(const QtPrivate::QMetaTypeInterface *type)
{
Q_ASSERT(type);
return QMetaType::TypeFlags(type->flags) & QMetaType::RelocatableType &&
@ -468,14 +468,14 @@ public:
void set(const T &t)
{ *static_cast<T *>(CanUseInternalSpace<T> ? &data.data : data.shared->data()) = t; }
inline QMetaType type() const
inline const QtPrivate::QMetaTypeInterface* typeInterface() const
{
return QMetaType(reinterpret_cast<QtPrivate::QMetaTypeInterface *>(packedType << 2));
return reinterpret_cast<const QtPrivate::QMetaTypeInterface *>(packedType << 2);
}
inline QtPrivate::QMetaTypeInterface * typeInterface() const
inline QMetaType type() const
{
return reinterpret_cast<QtPrivate::QMetaTypeInterface *>(packedType << 2);
return QMetaType(typeInterface());
}
inline int typeId() const