Speed up object creation with lots of id name objects

In the common case when objects are referenced by id, we don't need the
QQmlContextData's property name cache for the lookup. Instead of bindings
we resolve the id to an integer at type compilation time. Therefore we can
delay the population of the QQmlContextData's propertyNames until we need it
and therefore safe time on startup.

Change-Id: I2e8eeb51b1ac92f230059be3467f9a1e00fdbbef
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

1 files changed, 28 insertions, 20 deletions

diff --git a/src/qml/qml/qqmlcontext.cpp b/src/qml/qml/qqmlcontext.cpp
index 1005d097d2..e641226b90 100644
--- a/src/qml/qml/qqmlcontext.cpp
+++ b/src/qml/qml/qqmlcontext.cpp
@@ -305,12 +305,10 @@ void QQmlContext::setContextProperty(const QString &name, const QVariant &value)
         }
     }
 
-    if (data->propertyNames.isEmpty())
-        data->propertyNames = QV4::IdentifierHash<int>(QV8Engine::getV4(engine()->handle()));
-
-    int idx = data->propertyNames.value(name);
+    QV4::IdentifierHash<int> &properties = data->propertyNames();
+    int idx = properties.value(name);
     if (idx == -1) {
-        data->propertyNames.add(name, data->idValueCount + d->propertyValues.count());
+        properties.add(name, data->idValueCount + d->propertyValues.count());
         d->propertyValues.append(value);
 
         data->refreshExpressions();
@@ -343,12 +341,11 @@ void QQmlContext::setContextProperty(const QString &name, QObject *value)
         return;
     }
 
-    if (data->propertyNames.isEmpty())
-        data->propertyNames = QV4::IdentifierHash<int>(QV8Engine::getV4(engine()->handle()));
-    int idx = data->propertyNames.value(name);
+    QV4::IdentifierHash<int> &properties = data->propertyNames();
+    int idx = properties.value(name);
 
     if (idx == -1) {
-        data->propertyNames.add(name, data->idValueCount + d->propertyValues.count());
+        properties.add(name, data->idValueCount + d->propertyValues.count());
         d->propertyValues.append(QVariant::fromValue(value));
 
         data->refreshExpressions();
@@ -370,8 +367,9 @@ QVariant QQmlContext::contextProperty(const QString &name) const
 
     QQmlContextData *data = d->data;
 
-    if (data->propertyNames.count())
-        idx = data->propertyNames.value(name);
+    const QV4::IdentifierHash<int> &properties = data->propertyNames();
+    if (properties.count())
+        idx = properties.value(name);
 
     if (idx == -1) {
         if (data->contextObject) {
@@ -764,31 +762,29 @@ void QQmlContextData::setIdProperty(int idx, QObject *obj)
 
 void QQmlContextData::setIdPropertyData(const QVector<ObjectIdMapping> &data)
 {
-    Q_ASSERT(propertyNames.isEmpty());
-    propertyNames = QV4::IdentifierHash<int>(QV8Engine::getV4(engine->handle()));
-    for (QVector<ObjectIdMapping>::ConstIterator it = data.begin(), end = data.end();
-         it != end; ++it)
-        propertyNames.add(it->name, it->id);
-
+    Q_ASSERT(idObjectNames.isEmpty());
+    idObjectNames = data;
+    Q_ASSERT(propertyNameCache.isEmpty());
     idValueCount = data.count();
     idValues = new ContextGuard[idValueCount];
 }
 
 QString QQmlContextData::findObjectId(const QObject *obj) const
 {
-    if (propertyNames.isEmpty())
+    const QV4::IdentifierHash<int> &properties = propertyNames();
+    if (propertyNameCache.isEmpty())
         return QString();
 
     for (int ii = 0; ii < idValueCount; ii++) {
         if (idValues[ii] == obj)
-            return propertyNames.findId(ii);
+            return properties.findId(ii);
     }
 
     if (publicContext) {
         QQmlContextPrivate *p = QQmlContextPrivate::get(publicContext);
         for (int ii = 0; ii < p->propertyValues.count(); ++ii)
             if (p->propertyValues.at(ii) == QVariant::fromValue((QObject *)obj))
-                return propertyNames.findId(ii);
+                return properties.findId(ii);
     }
 
     if (linkedContext)
@@ -808,4 +804,16 @@ QQmlContextPrivate *QQmlContextData::asQQmlContextPrivate()
     return QQmlContextPrivate::get(asQQmlContext());
 }
 
+QV4::IdentifierHash<int> &QQmlContextData::propertyNames() const
+{
+    if (propertyNameCache.isEmpty()) {
+        propertyNameCache = QV4::IdentifierHash<int>(QV8Engine::getV4(engine->handle()));
+        for (QVector<ObjectIdMapping>::ConstIterator it = idObjectNames.begin(), end = idObjectNames.end();
+             it != end; ++it)
+            propertyNameCache.add(it->name, it->id);
+        idObjectNames.clear();
+    }
+    return propertyNameCache;
+}
+
 QT_END_NAMESPACE