Improve efficiency of qmlEngine()

Also document qmlEngine() and qmlContext()

Change-Id: I83eb092490160eee72d87473befdcea1492ded13
Reviewed-on: http://codereview.qt-project.org/4491
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Aaron Kennedy <aaron.kennedy@nokia.com>

diff --git a/src/declarative/qml/qdeclarativeengine.cpp b/src/declarative/qml/qdeclarativeengine.cpp
index 789c9ed..9c7c0ab 100644 (file)
--- a/src/declarative/qml/qdeclarativeengine.cpp
+++ b/src/declarative/qml/qdeclarativeengine.cpp
@@ -948,8 +948,10 @@ QDeclarativeContext *qmlContext(const QObject *obj)
 
 QDeclarativeEngine *qmlEngine(const QObject *obj)
 {
-    QDeclarativeContext *context = QDeclarativeEngine::contextForObject(obj);
-    return context?context->engine():0;
+    QDeclarativeData *data = QDeclarativeData::get(obj, false);
+    if (!data || !data->context)
+        return 0;
+    return data->context->engine;
 }
 
 QObject *qmlAttachedPropertiesObjectById(int id, const QObject *object, bool create)
@@ -1681,4 +1683,20 @@ bool QDeclarative_isFileCaseCorrect(const QString &fileName)
     return true;
 }
 
+/*!
+    \fn QDeclarativeEngine *qmlEngine(const QObject *object)
+    \relates QDeclarativeEngine
+
+    Returns the QDeclarativeEngine associated with \a object, if any.  This is equivalent to
+    QDeclarativeEngine::contextForObject(object)->engine(), but more efficient.
+*/
+
+/*!
+    \fn QDeclarativeContext *qmlContext(const QObject *object)
+    \relates QDeclarativeEngine
+
+    Returns the QDeclarativeContext associated with \a object, if any.  This is equivalent to
+    QDeclarativeEngine::contextForObject(object).
+*/
+
 QT_END_NAMESPACE