diff options
| author | Ulf Hermann <ulf.hermann@qt.io> | 2021-03-11 11:07:58 +0100 |
|---|---|---|
| committer | Ulf Hermann <ulf.hermann@qt.io> | 2021-03-13 10:08:48 +0100 |
| commit | eb2386a04260966c5d1f13941f7a10154e11625a (patch) | |
| tree | 2bbe824419230c62de6d88f255f45819c757a62b /src/qml/jsruntime/qv4engine.cpp | |
| parent | a9c93e2716a097c637515aded49a3308e257204b (diff) | |
Optimize ExecutionEngine::metaTypeToJS()
We almost never need to construct a QVariant to do this. Constructing a
QVariant is excessively expensive if you have something simple like an
integer. This also fixes the unexpected "unwrapping" of variants when we
pass them through QJSValue.
[ChangeLog][QtQml][Important Behavior Changes] If you create a QJSValue
from a nested QVariant (that is, a QVariant containing another
QVariant), then, when retrieving its contents again, the outer variant
is not unwrapped anymore. Rather, you get exactly the value you've
passed in.
Change-Id: I8c16eed4f13e8cfdeced0756eef593b3b8e84dd1
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Diffstat (limited to 'src/qml/jsruntime/qv4engine.cpp')
| -rw-r--r-- | src/qml/jsruntime/qv4engine.cpp | 50 |
1 files changed, 32 insertions, 18 deletions
diff --git a/src/qml/jsruntime/qv4engine.cpp b/src/qml/jsruntime/qv4engine.cpp index 0c95950400..4897454cec 100644 --- a/src/qml/jsruntime/qv4engine.cpp +++ b/src/qml/jsruntime/qv4engine.cpp @@ -1722,12 +1722,18 @@ static QVariant objectToVariant(QV4::ExecutionEngine *e, const QV4::Object *o, V return result; } -QV4::ReturnedValue QV4::ExecutionEngine::fromVariant(const QVariant &variant) -{ - const QMetaType metaType = variant.metaType(); - int type = metaType.id(); - const void *ptr = variant.constData(); - +/*! + \internal + + Transform the given \a metaType and \a ptr into a JavaScript representation. You can pass an + optional \a variant in order to avoid the construction of a new QVariant in case the value + has to be stored as a variant object. In that case, the contents of \a variant have to be + exactly the same as \a metaType and \a ptr. + */ +QV4::ReturnedValue ExecutionEngine::fromData( + const QMetaType &metaType, const void *ptr, const QVariant *variant) +{ + const int type = metaType.id(); if (type < QMetaType::User) { switch (QMetaType::Type(type)) { case QMetaType::UnknownType: @@ -1783,7 +1789,8 @@ QV4::ReturnedValue QV4::ExecutionEngine::fromVariant(const QVariant &variant) { bool succeeded = false; QV4::Scope scope(this); - QV4::ScopedValue retn(scope, QV4::SequencePrototype::fromVariant(this, variant, &succeeded)); + QV4::ScopedValue retn( + scope, QV4::SequencePrototype::fromData(this, metaType, ptr, &succeeded)); if (succeeded) return retn->asReturnedValue(); return QV4::Encode(newArrayObject(*reinterpret_cast<const QStringList *>(ptr))); @@ -1806,13 +1813,13 @@ QV4::ReturnedValue QV4::ExecutionEngine::fromVariant(const QVariant &variant) case QMetaType::QPixmap: case QMetaType::QImage: // Scarce value types - return QV4::Encode(newVariantObject(variant)); + return QV4::Encode(newVariantObject(variant ? *variant : QVariant(metaType, ptr))); default: break; } if (const QMetaObject *vtmo = QQmlMetaType::metaObjectForMetaType(metaType)) - return QV4::QQmlValueTypeWrapper::create(this, variant, vtmo, metaType); + return QV4::QQmlValueTypeWrapper::create(this, ptr, vtmo, metaType); } else { QV4::Scope scope(this); if (type == qMetaTypeId<QQmlListReference>()) { @@ -1852,25 +1859,32 @@ QV4::ReturnedValue QV4::ExecutionEngine::fromVariant(const QVariant &variant) #if QT_CONFIG(qml_sequence_object) bool succeeded = false; - QV4::ScopedValue retn(scope, QV4::SequencePrototype::fromVariant(this, variant, &succeeded)); + QV4::ScopedValue retn(scope, QV4::SequencePrototype::fromData(this, metaType, ptr, &succeeded)); if (succeeded) return retn->asReturnedValue(); #endif - if (QMetaType::canConvert(variant.metaType(), QMetaType::fromType<QSequentialIterable>())) { - QSequentialIterable lst = variant.value<QSequentialIterable>(); + + if (QMetaType::canConvert(metaType, QMetaType::fromType<QSequentialIterable>())) { + QSequentialIterable lst; + QMetaType::convert(metaType, ptr, QMetaType::fromType<QSequentialIterable>(), &lst); return sequentialIterableToJS(this, lst); } if (const QMetaObject *vtmo = QQmlMetaType::metaObjectForMetaType(metaType)) - return QV4::QQmlValueTypeWrapper::create(this, variant, vtmo, metaType); + return QV4::QQmlValueTypeWrapper::create(this, ptr, vtmo, metaType); } // XXX TODO: To be compatible, we still need to handle: // + QObjectList // + QList<int> - return QV4::Encode(newVariantObject(variant)); + return QV4::Encode(newVariantObject(variant ? *variant : QVariant(metaType, ptr))); +} + +QV4::ReturnedValue QV4::ExecutionEngine::fromVariant(const QVariant &variant) +{ + return fromData(variant.metaType(), variant.constData(), &variant); } QVariantMap ExecutionEngine::variantMapFromJS(const Object *o) @@ -1940,13 +1954,13 @@ QV4::ReturnedValue ExecutionEngine::metaTypeToJS(QMetaType type, const void *dat { Q_ASSERT(data != nullptr); - QVariant variant(type, data); - if (QMetaType::Type(variant.userType()) == QMetaType::QVariant) { + if (type == QMetaType::fromType<QVariant>()) { // unwrap it: this is tested in QJSEngine, and makes the most sense for // end-user code too. - return variantToJS(this, *reinterpret_cast<const QVariant*>(data)); + return fromVariant(*reinterpret_cast<const QVariant*>(data)); } - return fromVariant(variant); + + return fromData(type, data); } int ExecutionEngine::maxJSStackSize() const |