/**************************************************************************** ** ** Copyright (C) 2016 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the QtQml module of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:LGPL$ ** Commercial License Usage ** Licensees holding valid commercial Qt licenses may use this file in ** accordance with the commercial license agreement provided with the ** Software or, alternatively, in accordance with the terms contained in ** a written agreement between you and The Qt Company. For licensing terms ** and conditions see https://www.qt.io/terms-conditions. For further ** information use the contact form at https://www.qt.io/contact-us. ** ** GNU Lesser General Public License Usage ** Alternatively, this file may be used under the terms of the GNU Lesser ** General Public License version 3 as published by the Free Software ** Foundation and appearing in the file LICENSE.LGPL3 included in the ** packaging of this file. Please review the following information to ** ensure the GNU Lesser General Public License version 3 requirements ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. ** ** GNU General Public License Usage ** Alternatively, this file may be used under the terms of the GNU ** General Public License version 2.0 or (at your option) the GNU General ** Public license version 3 or any later version approved by the KDE Free ** Qt Foundation. The licenses are as published by the Free Software ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 ** included in the packaging of this file. Please review the following ** information to ensure the GNU General Public License requirements will ** be met: https://www.gnu.org/licenses/gpl-2.0.html and ** https://www.gnu.org/licenses/gpl-3.0.html. ** ** $QT_END_LICENSE$ ** ****************************************************************************/ #include "qqmllist.h" #include "qqmllist_p.h" #include "qqmlengine_p.h" #include "qqmlproperty_p.h" QT_BEGIN_NAMESPACE QQmlListReferencePrivate::QQmlListReferencePrivate() : propertyType(-1), refCount(1) { } QQmlListReference QQmlListReferencePrivate::init(const QQmlListProperty &prop, int propType, QQmlEngine *engine) { QQmlListReference rv; if (!prop.object) return rv; QQmlEnginePrivate *p = engine?QQmlEnginePrivate::get(engine):nullptr; int listType = p?p->listType(propType):QQmlMetaType::listType(propType); if (listType == -1) return rv; rv.d = new QQmlListReferencePrivate; rv.d->object = prop.object; rv.d->elementType = QQmlPropertyPrivate::rawMetaObjectForType(p, listType); rv.d->property = prop; rv.d->propertyType = propType; return rv; } void QQmlListReferencePrivate::addref() { Q_ASSERT(refCount > 0); ++refCount; } void QQmlListReferencePrivate::release() { Q_ASSERT(refCount > 0); --refCount; if (!refCount) delete this; } /*! \class QQmlListReference \since 5.0 \inmodule QtQml \brief The QQmlListReference class allows the manipulation of QQmlListProperty properties. QQmlListReference allows C++ programs to read from, and assign values to a QML list property in a simple and type-safe way. A QQmlListReference can be created by passing an object and property name or through a QQmlProperty instance. These two are equivalent: \code QQmlListReference ref1(object, "children"); QQmlProperty ref2(object, "children"); QQmlListReference ref2 = qvariant_cast(ref2.read()); \endcode Not all QML list properties support all operations. A set of methods, canAppend(), canAt(), canClear() and canCount() allow programs to query whether an operation is supported on a given property. QML list properties are type-safe. Only QObject's that derive from the correct base class can be assigned to the list. The listElementType() method can be used to query the QMetaObject of the QObject type supported. Attempting to add objects of the incorrect type to a list property will fail. Like with normal lists, when accessing a list element by index, it is the callers responsibility to ensure that it does not request an out of range element using the count() method before calling at(). */ /*! Constructs an invalid instance. */ QQmlListReference::QQmlListReference() : d(nullptr) { } /*! Constructs a QQmlListReference for \a object's \a property. If \a property is not a list property, an invalid QQmlListReference is created. If \a object is destroyed after the reference is constructed, it will automatically become invalid. That is, it is safe to hold QQmlListReference instances even after \a object is deleted. Passing \a engine is required to access some QML created list properties. If in doubt, and an engine is available, pass it. */ QQmlListReference::QQmlListReference(QObject *object, const char *property, QQmlEngine *engine) : d(nullptr) { if (!object || !property) return; QQmlPropertyData local; QQmlPropertyData *data = QQmlPropertyCache::property(engine, object, QLatin1String(property), nullptr, &local); if (!data || !data->isQList()) return; QQmlEnginePrivate *p = engine?QQmlEnginePrivate::get(engine):nullptr; int listType = p?p->listType(data->propType()):QQmlMetaType::listType(data->propType()); if (listType == -1) return; d = new QQmlListReferencePrivate; d->object = object; d->elementType = p ? p->rawMetaObjectForType(listType) : QQmlMetaType::qmlType(listType).baseMetaObject(); d->propertyType = data->propType(); void *args[] = { &d->property, nullptr }; QMetaObject::metacall(object, QMetaObject::ReadProperty, data->coreIndex(), args); } /*! \internal */ QQmlListReference::QQmlListReference(const QQmlListReference &o) : d(o.d) { if (d) d->addref(); } /*! \internal */ QQmlListReference &QQmlListReference::operator=(const QQmlListReference &o) { if (o.d) o.d->addref(); if (d) d->release(); d = o.d; return *this; } /*! \internal */ QQmlListReference::~QQmlListReference() { if (d) d->release(); } /*! Returns true if the instance refers to a valid list property, otherwise false. */ bool QQmlListReference::isValid() const { return d && d->object; } /*! Returns the list property's object. Returns \nullptr if the reference is invalid. */ QObject *QQmlListReference::object() const { if (isValid()) return d->object; else return nullptr; } /*! Returns the QMetaObject for the elements stored in the list property, or \nullptr if the reference is invalid. The QMetaObject can be used ahead of time to determine whether a given instance can be added to a list. */ const QMetaObject *QQmlListReference::listElementType() const { if (isValid()) return d->elementType.metaObject(); else return nullptr; } /*! Returns true if the list property can be appended to, otherwise false. Returns false if the reference is invalid. \sa append() */ bool QQmlListReference::canAppend() const { return (isValid() && d->property.append); } /*! Returns true if the list property can queried by index, otherwise false. Returns false if the reference is invalid. \sa at() */ bool QQmlListReference::canAt() const { return (isValid() && d->property.at); } /*! Returns true if the list property can be cleared, otherwise false. Returns false if the reference is invalid. \sa clear() */ bool QQmlListReference::canClear() const { return (isValid() && d->property.clear); } /*! Returns true if the list property can be queried for its element count, otherwise false. Returns false if the reference is invalid. \sa count() */ bool QQmlListReference::canCount() const { return (isValid() && d->property.count); } /*! Returns true if items in the list property can be replaced, otherwise false. Returns false if the reference is invalid. \sa replace() */ bool QQmlListReference::canReplace() const { return (isValid() && d->property.replace); } /*! Returns true if the last item can be removed from the list property, otherwise false. Returns false if the reference is invalid. \sa removeLast() */ bool QQmlListReference::canRemoveLast() const { return (isValid() && d->property.removeLast); } /*! Return true if at(), count(), append(), and either clear() or removeLast() are implemented, so you can manipulate the list. Mind that replace() and removeLast() can be emulated by stashing all items and rebuilding the list using clear() and append(). Therefore, they are not required for the list to be manipulable. Furthermore, clear() can be emulated using removeLast(). \sa isReadable(), at(), count(), append(), clear(), replace(), removeLast() */ bool QQmlListReference::isManipulable() const { return (isValid() && d->property.append && d->property.count && d->property.at && d->property.clear); } /*! Return true if at() and count() are implemented, so you can access the elements. \sa isManipulable(), at(), count() */ bool QQmlListReference::isReadable() const { return (isValid() && d->property.count && d->property.at); } /*! Appends \a object to the list. Returns true if the operation succeeded, otherwise false. \sa canAppend() */ bool QQmlListReference::append(QObject *object) const { if (!canAppend()) return false; if (object && !QQmlMetaObject::canConvert(object, d->elementType)) return false; d->property.append(&d->property, object); return true; } /*! Returns the list element at \a index, or 0 if the operation failed. \sa canAt() */ QObject *QQmlListReference::at(qsizetype index) const { if (!canAt()) return nullptr; return d->property.at(&d->property, index); } /*! Clears the list. Returns true if the operation succeeded, otherwise false. \sa canClear() */ bool QQmlListReference::clear() const { if (!canClear()) return false; d->property.clear(&d->property); return true; } /*! Returns the number of objects in the list, or 0 if the operation failed. */ qsizetype QQmlListReference::count() const { if (!canCount()) return 0; return d->property.count(&d->property); } /*! Replaces the item at \a index in the list with \a object. Returns true if the operation succeeded, otherwise false. \sa canReplace() */ bool QQmlListReference::replace(qsizetype index, QObject *object) const { if (!canReplace()) return false; if (object && !QQmlMetaObject::canConvert(object, d->elementType)) return false; d->property.replace(&d->property, index, object); return true; } /*! Removes the last item in the list. Returns true if the operation succeeded, otherwise false. \sa canRemoveLast() */ bool QQmlListReference::removeLast() const { if (!canRemoveLast()) return false; d->property.removeLast(&d->property); return true; } /*! \class QQmlListProperty \since 5.0 \inmodule QtQml \brief The QQmlListProperty class allows applications to expose list-like properties of QObject-derived classes to QML. QML has many list properties, where more than one object value can be assigned. The use of a list property from QML looks like this: \code FruitBasket { fruit: [ Apple {}, Orange{}, Banana{} ] } \endcode The QQmlListProperty encapsulates a group of function pointers that represent the set of actions QML can perform on the list - adding items, retrieving items and clearing the list. In the future, additional operations may be supported. All list properties must implement the append operation, but the rest are optional. To provide a list property, a C++ class must implement the operation callbacks, and then return an appropriate QQmlListProperty value from the property getter. List properties should have no setter. In the example above, the Q_PROPERTY() declarative will look like this: \code Q_PROPERTY(QQmlListProperty fruit READ fruit) \endcode QML list properties are type-safe - in this case \c {Fruit} is a QObject type that \c {Apple}, \c {Orange} and \c {Banana} all derive from. \sa {Extending QML - Object and List Property Types Example} */ /*! \macro QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_APPEND \relates QQmlListProperty This macro defines the behavior of the list properties of this class to Append. When assigning the property in a derived type, the values are appended to those of the base class. This is the default behavior. \code class FruitBasket : QObject { \Q_OBJECT QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_APPEND Q_PROPERTY(QQmlListProperty fruit READ fruit) public: // ... QQmlListProperty fruit(); // ... }; \endcode \sa QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_REPLACE_IF_NOT_DEFAULT \sa QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_REPLACE */ /*! \macro QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_REPLACE_IF_NOT_DEFAULT \relates QQmlListProperty This macro defines the behavior of the list properties of this class to ReplaceIfNotDefault. When assigning the property in a derived type, the values replace those of the base class unless it's the default property. In the case of the default property, values are appended to those of the base class. \code class FruitBasket : QObject { \Q_OBJECT QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_REPLACE_IF_NOT_DEFAULT Q_PROPERTY(QQmlListProperty fruit READ fruit) public: // ... QQmlListProperty fruit(); // ... }; \endcode \sa QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_APPEND \sa QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_REPLACE */ /*! \macro QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_REPLACE \relates QQmlListProperty This macro defines the behavior of the list properties of this class to Replace. When assigning the property in a derived type, the values replace those of the base class. \code class FruitBasket : QObject { \Q_OBJECT QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_REPLACE Q_PROPERTY(QQmlListProperty fruit READ fruit) public: // ... QQmlListProperty fruit(); // ... }; \endcode \sa QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_APPEND \sa QML_LIST_PROPERTY_ASSIGN_BEHAVIOR_REPLACE_IF_NOT_DEFAULT */ /*! \fn template QQmlListProperty::QQmlListProperty() \internal */ /*! \fn template QQmlListProperty::QQmlListProperty(QObject *object, QList &list) \deprecated Convenience constructor for making a QQmlListProperty value from an existing QList \a list. The \a list reference must remain valid for as long as \a object exists. \a object must be provided. This constructor synthesizes the removeLast() and replace() methods introduced in Qt 5.15, using count(), at(), clear(), and append(). This is slow. If you intend to manipulate the list beyond clearing it, you should explicitly provide these methods. */ /*! \fn template QQmlListProperty::QQmlListProperty(QObject *object, QList *list) \since 5.15 Convenience constructor for making a QQmlListProperty value from an existing QList \a list. The \a list reference must remain valid for as long as \a object exists. \a object must be provided. */ /*! \fn template QQmlListProperty::QQmlListProperty(QObject *object, void *data, CountFunction count, AtFunction at) Construct a readonly QQmlListProperty from a set of operation functions \a count and \a at. An opaque \a data handle may be passed which can be accessed from within the operation functions. The list property remains valid while \a object exists. */ /*! \fn template QQmlListProperty::QQmlListProperty(QObject *object, void *data, AppendFunction append, CountFunction count, AtFunction at, ClearFunction clear) Construct a QQmlListProperty from a set of operation functions \a append, \a count, \a at, and \a clear. An opaque \a data handle may be passed which can be accessed from within the operation functions. The list property remains valid while \a object exists. Null pointers can be passed for any function. If any null pointers are passed in, the list will be neither designable nor alterable by the debugger. It is recommended to provide valid pointers for all functions. \note The resulting QQmlListProperty will synthesize the removeLast() and replace() methods using \a count, \a at, \a clear, and \a append if all of those are given. This is slow. If you intend to manipulate the list beyond clearing it, you should explicitly provide these methods. */ /*! \fn template QQmlListProperty::QQmlListProperty( QObject *object, void *data, AppendFunction append, CountFunction count, AtFunction at, ClearFunction clear, ReplaceFunction replace, RemoveLastFunction removeLast) Construct a QQmlListProperty from a set of operation functions \a append, \a count, \a at, \a clear, \a replace, and \removeLast. An opaque \a data handle may be passed which can be accessed from within the operation functions. The list property remains valid while \a object exists. Null pointers can be passed for any function, causing the respective function to be synthesized using the others, if possible. QQmlListProperty can synthesize \list \li \a clear using \a count and \a removeLast \li \a replace using \a count, \a at, \a clear, and \a append \li \a replace using \a count, \a at, \a removeLast, and \a append \li \a removeLast using \a count, \a at, \a clear, and \a append \endlist if those are given. This is slow, but if your list does not natively provide faster options for these primitives, you may want to use the synthesized ones. Furthermore, if either of \a count, \a at, \a append, and \a clear are neither given explicitly nor synthesized, the list will be neither designable nor alterable by the debugger. It is recommended to provide enough valid pointers to avoid this situation. */ /*! \typedef QQmlListProperty::AppendFunction Synonym for \c {void (*)(QQmlListProperty *property, T *value)}. Append the \a value to the list \a property. */ /*! \typedef QQmlListProperty::CountFunction Synonym for \c {qsizetype (*)(QQmlListProperty *property)}. Return the number of elements in the list \a property. */ /*! \fn template bool QQmlListProperty::operator==(const QQmlListProperty &other) const Returns true if this QQmlListProperty is equal to \a other, otherwise false. */ /*! \typedef QQmlListProperty::AtFunction Synonym for \c {T *(*)(QQmlListProperty *property, qsizetype index)}. Return the element at position \a index in the list \a property. */ /*! \typedef QQmlListProperty::ClearFunction Synonym for \c {void (*)(QQmlListProperty *property)}. Clear the list \a property. */ /*! \typedef QQmlListProperty::ReplaceFunction Synonym for \c {void (*)(QQmlListProperty *property, qsizetype index, T *value)}. Replace the element at position \a index in the list \a property with \a value. */ /*! \typedef QQmlListProperty::RemoveLastFunction Synonym for \c {void (*)(QQmlListProperty *property)}. Remove the last element from the list \a property. */ /*! \fn bool QQmlListReference::operator==(const QQmlListReference &other) const Compares this QQmlListReference to \a other, and returns \c true if they are equal. The two are only considered equal if one was created from the other via copy assignment or copy construction. \note Independently created references to the same object are not considered to be equal. */ QT_END_NAMESPACE