Add a freeze() method to QQmlPropertyMap

After freezing a QQmlPropertyMap you cannot add any more properties, but
in turn the property access is cached, and therefore faster.

Task-number: QTBUG-57792
Change-Id: I2c6d768039c3b59eb2411194e463ee0de55f8bed
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

2 files changed, 17 insertions, 0 deletions

diff --git a/src/qml/util/qqmlpropertymap.cpp b/src/qml/util/qqmlpropertymap.cpp
index e38cf3a2a9..2bf8ab0190 100644
--- a/src/qml/util/qqmlpropertymap.cpp
+++ b/src/qml/util/qqmlpropertymap.cpp
@@ -204,6 +204,22 @@ void QQmlPropertyMap::clear(const QString &key)
 }
 
 /*!
+    \since 6.1
+
+    Disallows any further properties to be added to this property map.
+    Existing properties can be modified or cleared.
+
+    In turn, an internal cache is turned on for the existing properties, which
+    may result in faster access from QML.
+ */
+void QQmlPropertyMap::freeze()
+{
+    Q_D(QQmlPropertyMap);
+    d->mo->setAutoCreatesProperties(false);
+    d->mo->setCached(true);
+}
+
+/*!
     Returns the value associated with \a key.
 
     If no value has been set for this key (or if the value has been cleared),
diff --git a/src/qml/util/qqmlpropertymap.h b/src/qml/util/qqmlpropertymap.h
index 556754c021..de070673d7 100644
--- a/src/qml/util/qqmlpropertymap.h
+++ b/src/qml/util/qqmlpropertymap.h
@@ -62,6 +62,7 @@ public:
     void insert(const QString &key, const QVariant &value);
     void insert(const QVariantHash &values);
     void clear(const QString &key);
+    void freeze();
 
     Q_INVOKABLE QStringList keys() const;