Allow QQmlPropertyMap property updates to be controlled

Allow clients to control updates made from QML to types derived from
QQmlPropertyMap, by overriding the updateValue() function.

Task-number: QTBUG-23183
Change-Id: I0169093779ebfe50dc9349f5aaac08ed85c80a8f
Reviewed-by: Michael Brasser <michael.brasser@nokia.com>
Reviewed-by: abcd <amos.choy@nokia.com>

1 files changed, 38 insertions, 1 deletions

diff --git a/src/qml/util/qqmlpropertymap.cpp b/src/qml/util/qqmlpropertymap.cpp
index 1571d2dfc9..cdc82fe86e 100644
--- a/src/qml/util/qqmlpropertymap.cpp
+++ b/src/qml/util/qqmlpropertymap.cpp
@@ -56,9 +56,13 @@ public:
     QQmlPropertyMapMetaObject(QQmlPropertyMap *obj, QQmlPropertyMapPrivate *objPriv);
 
 protected:
+    virtual QVariant propertyWriteValue(int, const QVariant &);
     virtual void propertyWritten(int index);
     virtual void propertyCreated(int, QMetaPropertyBuilder &);
     virtual int createProperty(const char *, const char *);
+
+    const QString &propertyName(int index);
+
 private:
     QQmlPropertyMap *map;
     QQmlPropertyMapPrivate *priv;
@@ -70,8 +74,12 @@ class QQmlPropertyMapPrivate : public QObjectPrivate
 public:
     QQmlPropertyMapMetaObject *mo;
     QStringList keys;
+
+    QVariant updateValue(const QString &key, const QVariant &input);
     void emitChanged(const QString &key, const QVariant &value);
     bool validKeyName(const QString& name);
+
+    const QString &propertyName(int index) const;
 };
 
 bool QQmlPropertyMapPrivate::validKeyName(const QString& name)
@@ -84,21 +92,38 @@ bool QQmlPropertyMapPrivate::validKeyName(const QString& name)
          && name != QLatin1String("deleteLater");
 }
 
+QVariant QQmlPropertyMapPrivate::updateValue(const QString &key, const QVariant &input)
+{
+    Q_Q(QQmlPropertyMap);
+    return q->updateValue(key, input);
+}
+
 void QQmlPropertyMapPrivate::emitChanged(const QString &key, const QVariant &value)
 {
     Q_Q(QQmlPropertyMap);
     emit q->valueChanged(key, value);
 }
 
+const QString &QQmlPropertyMapPrivate::propertyName(int index) const
+{
+    Q_ASSERT(index < keys.size());
+    return keys[index];
+}
+
 QQmlPropertyMapMetaObject::QQmlPropertyMapMetaObject(QQmlPropertyMap *obj, QQmlPropertyMapPrivate *objPriv) : QQmlOpenMetaObject(obj)
 {
     map = obj;
     priv = objPriv;
 }
 
+QVariant QQmlPropertyMapMetaObject::propertyWriteValue(int index, const QVariant &input)
+{
+    return priv->updateValue(priv->propertyName(index), input);
+}
+
 void QQmlPropertyMapMetaObject::propertyWritten(int index)
 {
-    priv->emitChanged(QString::fromUtf8(name(index)), operator[](index));
+    priv->emitChanged(priv->propertyName(index), operator[](index));
 }
 
 void QQmlPropertyMapMetaObject::propertyCreated(int, QMetaPropertyBuilder &b)
@@ -298,6 +323,18 @@ QVariant QQmlPropertyMap::operator[](const QString &key) const
 }
 
 /*!
+    Returns the new value to be stored for the key \a key.  This function is provided
+    to intercept updates to a property from QML, where the value provided from QML is \a input.
+
+    Override this function to manipulate the property value as it is updated.  Note that
+    this function is only invoked when the value is updated from QML.
+*/
+QVariant QQmlPropertyMap::updateValue(const QString &key, const QVariant &input)
+{
+    return input;
+}
+
+/*!
     \fn void QQmlPropertyMap::valueChanged(const QString &key, const QVariant &value)
     This signal is emitted whenever one of the values in the map is changed. \a key
     is the key corresponding to the \a value that was changed.