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>

5 files changed, 103 insertions, 13 deletions

diff --git a/src/qml/qml/qqmlopenmetaobject.cpp b/src/qml/qml/qqmlopenmetaobject.cpp
index 221cb3a314..4774f7e126 100644
--- a/src/qml/qml/qqmlopenmetaobject.cpp
+++ b/src/qml/qml/qqmlopenmetaobject.cpp
@@ -145,10 +145,14 @@ public:
     QQmlOpenMetaObjectPrivate(QQmlOpenMetaObject *_q)
         : q(_q), parent(0), type(0), cacheProperties(false) {}
 
-    inline QVariant &getData(int idx) {
+    inline QPair<QVariant, bool> &getDataRef(int idx) {
         while (data.count() <= idx)
             data << QPair<QVariant, bool>(QVariant(), false);
-        QPair<QVariant, bool> &prop = data[idx];
+        return data[idx];
+    }
+
+    inline QVariant &getData(int idx) {
+        QPair<QVariant, bool> &prop = getDataRef(idx);
         if (!prop.second) {
             prop.first = q->initialValue(idx);
             prop.second = true;
@@ -156,14 +160,6 @@ public:
         return prop.first;
     }
 
-    inline void writeData(int idx, const QVariant &value) {
-        while (data.count() <= idx)
-            data << QPair<QVariant, bool>(QVariant(), false);
-        QPair<QVariant, bool> &prop = data[idx];
-        prop.first = value;
-        prop.second = true;
-    }
-
     inline bool hasData(int idx) const {
         if (idx >= data.count())
             return false;
@@ -235,7 +231,9 @@ int QQmlOpenMetaObject::metaCall(QMetaObject::Call c, int id, void **a)
         } else if (c == QMetaObject::WriteProperty) {
             if (propId <= d->data.count() || d->data[propId].first != *reinterpret_cast<QVariant *>(a[0]))  {
                 propertyWrite(propId);
-                d->writeData(propId, *reinterpret_cast<QVariant *>(a[0]));
+                QPair<QVariant, bool> &prop = d->getDataRef(propId);
+                prop.first = propertyWriteValue(propId, *reinterpret_cast<QVariant *>(a[0]));
+                prop.second = true;
                 propertyWritten(propId);
                 activate(d->object, d->type->d->signalOffset + propId, 0);
             }
@@ -261,7 +259,9 @@ QVariant QQmlOpenMetaObject::value(int id) const
 
 void QQmlOpenMetaObject::setValue(int id, const QVariant &value)
 {
-    d->writeData(id, value);
+    QPair<QVariant, bool> &prop = d->getDataRef(id);
+    prop.first = propertyWriteValue(id, value);
+    prop.second = true;
     activate(d->object, id + d->type->d->signalOffset, 0);
 }
 
@@ -354,6 +354,11 @@ void QQmlOpenMetaObject::propertyWrite(int)
 {
 }
 
+QVariant QQmlOpenMetaObject::propertyWriteValue(int, const QVariant &value)
+{
+    return value;
+}
+
 void QQmlOpenMetaObject::propertyWritten(int)
 {
 }
diff --git a/src/qml/qml/qqmlopenmetaobject_p.h b/src/qml/qml/qqmlopenmetaobject_p.h
index 188192edc1..a45d7d8259 100644
--- a/src/qml/qml/qqmlopenmetaobject_p.h
+++ b/src/qml/qml/qqmlopenmetaobject_p.h
@@ -113,6 +113,7 @@ protected:
 
     virtual void propertyRead(int);
     virtual void propertyWrite(int);
+    virtual QVariant propertyWriteValue(int, const QVariant &);
     virtual void propertyWritten(int);
     virtual void propertyCreated(int, QMetaPropertyBuilder &);
 
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.
diff --git a/src/qml/util/qqmlpropertymap.h b/src/qml/util/qqmlpropertymap.h
index 53254ab672..bfd11e5c80 100644
--- a/src/qml/util/qqmlpropertymap.h
+++ b/src/qml/util/qqmlpropertymap.h
@@ -79,6 +79,9 @@ public:
 Q_SIGNALS:
     void valueChanged(const QString &key, const QVariant &value);
 
+protected:
+    virtual QVariant updateValue(const QString &key, const QVariant &input);
+
 private:
     Q_DECLARE_PRIVATE(QQmlPropertyMap)
     Q_DISABLE_COPY(QQmlPropertyMap)
diff --git a/tests/auto/qml/qqmlpropertymap/tst_qqmlpropertymap.cpp b/tests/auto/qml/qqmlpropertymap/tst_qqmlpropertymap.cpp
index 0ae05ce138..4e39ad3a41 100644
--- a/tests/auto/qml/qqmlpropertymap/tst_qqmlpropertymap.cpp
+++ b/tests/auto/qml/qqmlpropertymap/tst_qqmlpropertymap.cpp
@@ -45,6 +45,7 @@
 #include <QtQml/qqmlcomponent.h>
 #include <QtQuick/private/qquicktext_p.h>
 #include <QSignalSpy>
+#include <QDebug>
 
 class tst_QQmlPropertyMap : public QObject
 {
@@ -59,6 +60,7 @@ private slots:
     void clear();
     void changed();
     void count();
+    void controlledWrite();
 
     void crashBug();
     void QTBUG_17868();
@@ -205,6 +207,48 @@ void tst_QQmlPropertyMap::count()
     QCOMPARE(map.size(), map.count());
 }
 
+class MyPropertyMap : public QQmlPropertyMap
+{
+    Q_OBJECT
+protected:
+    virtual QVariant updateValue(const QString &key, const QVariant &src)
+    {
+        if (key == QLatin1String("key1")) {
+            // 'key1' must be all uppercase
+            const QString original(src.toString());
+            return QVariant(original.toUpper());
+        }
+
+        return src;
+    }
+};
+
+void tst_QQmlPropertyMap::controlledWrite()
+{
+    MyPropertyMap map;
+    QCOMPARE(map.isEmpty(), true);
+
+    //make changes in QML
+    QQmlEngine engine;
+    QQmlContext *ctxt = engine.rootContext();
+    ctxt->setContextProperty(QLatin1String("testdata"), &map);
+
+    const char *qmlSource =
+        "import QtQuick 2.0\n"
+        "Item { Component.onCompleted: { testdata.key1 = 'Hello World'; testdata.key2 = 'Goodbye' } }";
+
+    QQmlComponent component(&engine);
+    component.setData(qmlSource, QUrl::fromLocalFile(""));
+    QVERIFY(component.isReady());
+
+    QObject *obj = component.create();
+    QVERIFY(obj);
+    delete obj;
+
+    QCOMPARE(map.value(QLatin1String("key1")), QVariant("HELLO WORLD"));
+    QCOMPARE(map.value(QLatin1String("key2")), QVariant("Goodbye"));
+}
+
 void tst_QQmlPropertyMap::crashBug()
 {
     QQmlPropertyMap map;