Imports: de-duplicate some expensive calls

QMetaMethod::parameterNames() contains internal loop,
and we had quadratic behavior. Since operator[] was used
with temp object, also we had detach()ing.

QUrl::path() contains memory allocation.

To avoid these issues cache results of functions.

Change-Id: Ie4c3f0573a000342aff44de0dd4f744a146bb935
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 2 insertions, 1 deletions

diff --git a/src/imports/statemachine/signaltransition.cpp b/src/imports/statemachine/signaltransition.cpp
index 47efc9ec15..508e1e3685 100644
--- a/src/imports/statemachine/signaltransition.cpp
+++ b/src/imports/statemachine/signaltransition.cpp
@@ -78,8 +78,9 @@ bool SignalTransition::eventTest(QEvent *event)
     // Set arguments as context properties
     int count = e->arguments().count();
     QMetaMethod metaMethod = e->sender()->metaObject()->method(e->signalIndex());
+    const auto parameterNames = metaMethod.parameterNames();
     for (int i = 0; i < count; i++)
-        context.setContextProperty(metaMethod.parameterNames()[i], QVariant::fromValue(e->arguments().at(i)));
+        context.setContextProperty(parameterNames[i], QVariant::fromValue(e->arguments().at(i)));
 
     QQmlExpression expr(m_guard, &context, this);
     QVariant result = expr.evaluate();