Don't cache item indexes in VisualDataModel.

Sacrifice constant time lookup of indexes for rarely used features for
reduced memory usage.

Applications which use neither Packages, nor the VisualDataGroup api
don't ever need to query the index of an item so caching and maintaining
those indexes in unnecessary. Where they are used this add a cost
scanning for the index of an item in the cache, and in some instances
a lookup cost in the compositor.

Change-Id: I7d3c21a27a8a3c068c5ae2e1e326ff573c44d712
Reviewed-by: Martin Jones <martin.jones@nokia.com>

1 files changed, 17 insertions, 17 deletions

diff --git a/src/quick/items/qquickvisualadaptormodel.cpp b/src/quick/items/qquickvisualadaptormodel.cpp
index fa88932faa..4151c3695e 100644
--- a/src/quick/items/qquickvisualadaptormodel.cpp
+++ b/src/quick/items/qquickvisualadaptormodel.cpp
@@ -70,7 +70,7 @@ static v8::Handle<v8::Value> get_index(v8::Local<v8::String>, const v8::Accessor
     if (!data)
         V8THROW_ERROR("Not a valid VisualData object");
 
-    return v8::Int32::New(data->index[0]);
+    return v8::Int32::New(data->index);
 }
 
 static v8::Local<v8::ObjectTemplate> createConstructor()
@@ -252,7 +252,7 @@ int QQuickVDMCachedModelData::metaCall(QMetaObject::Call call, int id, void **ar
 {
     if (call == QMetaObject::ReadProperty && id >= type->propertyOffset) {
         const int propertyIndex = id - type->propertyOffset;
-        if (index[0] == -1) {
+        if (index == -1) {
             if (!cachedData.isEmpty()) {
                 *static_cast<QVariant *>(arguments[0]) = cachedData.at(
                     type->hasModelData ? 0 : propertyIndex);
@@ -263,7 +263,7 @@ int QQuickVDMCachedModelData::metaCall(QMetaObject::Call call, int id, void **ar
         return -1;
     } else if (call == QMetaObject::WriteProperty && id >= type->propertyOffset) {
         const int propertyIndex = id - type->propertyOffset;
-        if (index[0] == -1) {
+        if (index == -1) {
             const QMetaObject *meta = metaObject();
             if (cachedData.count() > 1) {
                 cachedData[propertyIndex] = *static_cast<QVariant *>(arguments[0]);
@@ -297,9 +297,9 @@ void QQuickVDMCachedModelData::setValue(const QString &role, const QVariant &val
 
 bool QQuickVDMCachedModelData::resolveIndex(const QQuickVisualAdaptorModel &, int idx)
 {
-    if (index[0] == -1) {
+    if (index == -1) {
         Q_ASSERT(idx >= 0);
-        index[0] = idx;
+        index = idx;
         cachedData.clear();
         emit modelIndexChanged();
         const QMetaObject *meta = metaObject();
@@ -321,7 +321,7 @@ v8::Handle<v8::Value> QQuickVDMCachedModelData::get_property(
 
     QQuickVDMCachedModelData *modelData = static_cast<QQuickVDMCachedModelData *>(data);
     const int propertyId = info.Data()->Int32Value();
-    if (data->index[0] == -1) {
+    if (data->index == -1) {
         if (!modelData->cachedData.isEmpty()) {
             return data->engine->fromVariant(
                     modelData->cachedData.at(modelData->type->hasModelData ? 0 : propertyId));
@@ -341,7 +341,7 @@ void QQuickVDMCachedModelData::set_property(
         V8THROW_ERROR_SETTER("Not a valid VisualData object");
 
     const int propertyId = info.Data()->Int32Value();
-    if (data->index[0] == -1) {
+    if (data->index == -1) {
         QQuickVDMCachedModelData *modelData = static_cast<QQuickVDMCachedModelData *>(data);
         if (!modelData->cachedData.isEmpty()) {
             if (modelData->cachedData.count() > 1) {
@@ -375,9 +375,9 @@ public:
 
     bool hasModelChildren() const
     {
-        if (index[0] >= 0 && *type->model) {
+        if (index >= 0 && *type->model) {
             const QAbstractItemModel * const model = type->model->aim();
-            return model->hasChildren(model->index(index[0], 0, type->model->rootIndex));
+            return model->hasChildren(model->index(index, 0, type->model->rootIndex));
         } else {
             return false;
         }
@@ -385,13 +385,13 @@ public:
 
     QVariant value(int role) const
     {
-        return type->model->aim()->index(index[0], 0, type->model->rootIndex).data(role);
+        return type->model->aim()->index(index, 0, type->model->rootIndex).data(role);
     }
 
     void setValue(int role, const QVariant &value)
     {
         type->model->aim()->setData(
-                type->model->aim()->index(index[0], 0, type->model->rootIndex), value, role);
+                type->model->aim()->index(index, 0, type->model->rootIndex), value, role);
     }
 
     v8::Handle<v8::Value> get()
@@ -414,9 +414,9 @@ public:
             V8THROW_ERROR("Not a valid VisualData object");
 
         const QQuickVisualAdaptorModel *const model = static_cast<QQuickVDMCachedModelData *>(data)->type->model;
-        if (data->index[0] >= 0 && *model) {
+        if (data->index >= 0 && *model) {
             const QAbstractItemModel * const aim = model->aim();
-            return v8::Boolean::New(aim->hasChildren(aim->index(data->index[0], 0, model->rootIndex)));
+            return v8::Boolean::New(aim->hasChildren(aim->index(data->index, 0, model->rootIndex)));
         } else {
             return v8::Boolean::New(false);
         }
@@ -549,7 +549,7 @@ public:
 
     QVariant value(int role) const
     {
-        return type->model->lmi()->data(index[0], role);
+        return type->model->lmi()->data(index, role);
     }
 
     void setValue(int, const QVariant &) {}
@@ -673,7 +673,7 @@ public:
 
     void setModelData(const QVariant &data)
     {
-        if (index[0] == -1 && data != cachedData) {
+        if (index == -1 && data != cachedData) {
             cachedData = data;
             emit modelDataChanged();
         }
@@ -706,8 +706,8 @@ public:
 
     bool resolveIndex(const QQuickVisualAdaptorModel &model, int idx)
     {
-        if (index[0] == -1) {
-            index[0] = idx;
+        if (index == -1) {
+            index = idx;
             cachedData = model.list.at(idx);
             emit modelIndexChanged();
             emit modelDataChanged();