diff options
| author | Ulf Hermann <ulf.hermann@qt.io> | 2020-09-10 18:30:22 +0200 |
|---|---|---|
| committer | Ulf Hermann <ulf.hermann@qt.io> | 2020-09-19 11:14:36 +0200 |
| commit | 217a25a6bf59bb9ce0845267f46244fedd8bcaaa (patch) | |
| tree | ae54c75f951553001472d5d8bb0f54e5a4f9056c /src/corelib/kernel/qvariant.h | |
| parent | 5c808073af5b8f1290602fcccf60666c9a3682f8 (diff) | |
QMetaType: Allow registration of mutable views and register iterables
In order to modify a container through an iterable, we need the original
container to be mutable. The iterable, then, is not a conversion of the
container, but rather a view on the container. The concept may be
extended to other types.
In order to facilitate this, provide a set of methods in QMetaType and
QVariant similar to the convert family. The new methods are non-const
and expect the original value to stay available during the life time of
the view.
Change-Id: I363621033f7fc600edcea2acb786820ccba49c86
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Diffstat (limited to 'src/corelib/kernel/qvariant.h')
| -rw-r--r-- | src/corelib/kernel/qvariant.h | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/src/corelib/kernel/qvariant.h b/src/corelib/kernel/qvariant.h index 1825d4be88..83cb40a7c7 100644 --- a/src/corelib/kernel/qvariant.h +++ b/src/corelib/kernel/qvariant.h @@ -248,6 +248,9 @@ class Q_CORE_EXPORT QVariant { return QMetaType::canConvert(d.type(), targetType); } bool convert(QMetaType type); + bool canView(QMetaType targetType) const + { return QMetaType::canView(d.type(), targetType); } + #if QT_DEPRECATED_SINCE(6, 0) QT_DEPRECATED_VERSION_6_0 bool canConvert(int targetTypeId) const @@ -364,6 +367,14 @@ class Q_CORE_EXPORT QVariant { return qvariant_cast<T>(*this); } template<typename T> + inline T view() + { + T t{}; + QMetaType::view(metaType(), data(), QMetaType::fromType<T>(), &t); + return t; + } + + template<typename T> static inline QVariant fromValue(const T &value) { return QVariant(QMetaType::fromType<T>(), std::addressof(value)); @@ -383,6 +394,10 @@ class Q_CORE_EXPORT QVariant bool canConvert() const { return canConvert(QMetaType::fromType<T>()); } + template<typename T> + bool canView() const + { return canView(QMetaType::fromType<T>()); } + public: struct PrivateShared { @@ -488,7 +503,8 @@ protected: Private d; void create(int type, const void *copy); bool equals(const QVariant &other) const; - bool convert(int t, void *ptr) const; + bool convert(int type, void *ptr) const; + bool view(int type, void *ptr); private: // force compile error, prevent QVariant(bool) to be called |