Use QObject declarative data to store attached properties.

An element's qmlAttachedProperties() function will now only ever get called once
per object.

1 files changed, 16 insertions, 0 deletions

diff --git a/src/declarative/qml/qml.h b/src/declarative/qml/qml.h
index fb288b7..2d8d83e 100644
--- a/src/declarative/qml/qml.h
+++ b/src/declarative/qml/qml.h
@@ -92,6 +92,22 @@ class QmlContext;
 class QmlEngine;
 Q_DECLARATIVE_EXPORT QmlContext *qmlContext(const QObject *);
 Q_DECLARATIVE_EXPORT QmlEngine *qmlEngine(const QObject *);
+Q_DECLARATIVE_EXPORT QObject *qmlAttachedPropertiesObjectById(int, const QObject *);
+
+template<typename T>
+QObject *qmlAttachedPropertiesObject(const QObject *obj)
+{
+    // ### is this threadsafe?
+    static int idx = -1;
+
+    if(idx == -1)
+        idx = QmlMetaType::attachedPropertiesFuncId(&T::staticMetaObject);
+
+    if(idx == -1 || !obj)
+        return 0;
+
+    return qmlAttachedPropertiesObjectById(obj, idx);
+}
 
 QML_DECLARE_TYPE(QObject);
 Q_DECLARE_METATYPE(QVariant);