From 5c50c19231943368ae1f07dbc63d57fac84445ca Mon Sep 17 00:00:00 2001
From: Andrew den Exter <andrew.den-exter@nokia.com>
Date: Tue, 5 Jun 2012 16:43:57 +1000
Subject: [PATCH] Don't cache visual data model v8 handles.

The external resource is reference counted and resused irregardless of
whether the handles are cached, and the reduction in the number of
handles allocated needs to be comes at the cost of keeping  persistent
handle which have a negative impact on garbage collection.

Change-Id: I92996faab08a0ff76d21e56dbdafdd7522882d2c
Reviewed-by: Chris Adams <christopher.adams@nokia.com>
---
 src/quick/items/qquickvisualadaptormodel.cpp |  2 ++
 src/quick/items/qquickvisualdatamodel.cpp    | 39 +++++-----------------------
 src/quick/items/qquickvisualdatamodel_p_p.h  |  2 --
 3 files changed, 9 insertions(+), 34 deletions(-)

diff --git a/src/quick/items/qquickvisualadaptormodel.cpp b/src/quick/items/qquickvisualadaptormodel.cpp
index 1179973..f298346 100644
--- a/src/quick/items/qquickvisualadaptormodel.cpp
+++ b/src/quick/items/qquickvisualadaptormodel.cpp
@@ -401,6 +401,7 @@ public:
         }
         v8::Local<v8::Object> data = type->constructor->NewInstance();
         data->SetExternalResource(this);
+        ++scriptRef;
         return data;
     }
 
@@ -559,6 +560,7 @@ public:
         }
         v8::Local<v8::Object> data = type->constructor->NewInstance();
         data->SetExternalResource(this);
+        ++scriptRef;
         return data;
     }
 };
diff --git a/src/quick/items/qquickvisualdatamodel.cpp b/src/quick/items/qquickvisualdatamodel.cpp
index 0570941..2f31aca 100644
--- a/src/quick/items/qquickvisualdatamodel.cpp
+++ b/src/quick/items/qquickvisualdatamodel.cpp
@@ -1612,18 +1612,6 @@ int QQuickVisualDataModelItemMetaType::parseGroups(const v8::Local<v8::Value> &g
     return groupFlags;
 }
 
-void QQuickVisualDataModelItemMetaType::release_index(v8::Persistent<v8::Value> object, void *data)
-{
-    static_cast<QQuickVisualDataModelItem *>(data)->indexHandle.Clear();
-    qPersistentDispose(object);
-}
-
-void QQuickVisualDataModelItemMetaType::release_model(v8::Persistent<v8::Value> object, void *data)
-{
-    static_cast<QQuickVisualDataModelItem *>(data)->modelHandle.Clear();
-    qPersistentDispose(object);
-}
-
 v8::Handle<v8::Value> QQuickVisualDataModelItemMetaType::get_model(
         v8::Local<v8::String>, const v8::AccessorInfo &info)
 {
@@ -1632,14 +1620,7 @@ v8::Handle<v8::Value> QQuickVisualDataModelItemMetaType::get_model(
     if (!cacheItem->metaType->model)
         return v8::Undefined();
 
-    if (cacheItem->modelHandle.IsEmpty()) {
-        cacheItem->modelHandle = qPersistentNew(cacheItem->get());
-        cacheItem->modelHandle.MakeWeak(cacheItem, &release_model);
-
-        ++cacheItem->scriptRef;
-    }
-
-    return cacheItem->modelHandle;
+    return cacheItem->get();
 }
 
 v8::Handle<v8::Value> QQuickVisualDataModelItemMetaType::get_groups(
@@ -1739,8 +1720,6 @@ QQuickVisualDataModelItem::~QQuickVisualDataModelItem()
     Q_ASSERT(scriptRef == 0);
     Q_ASSERT(objectRef == 0);
     Q_ASSERT(!object);
-    Q_ASSERT(indexHandle.IsEmpty());
-    Q_ASSERT(modelHandle.IsEmpty());
 
     if (incubationTask && metaType->model)
         QQuickVisualDataModelPrivate::get(metaType->model)->releaseIncubator(incubationTask);
@@ -2257,17 +2236,13 @@ QQmlV8Handle QQuickVisualDataGroup::get(int index)
         model->m_compositor.setFlags(it, 1, Compositor::CacheFlag);
     }
 
-    if (cacheItem->indexHandle.IsEmpty()) {
-        if (model->m_cacheMetaType->constructor.IsEmpty())
-            model->m_cacheMetaType->initializeConstructor();
-        cacheItem->indexHandle = qPersistentNew(model->m_cacheMetaType->constructor->NewInstance());
-        cacheItem->indexHandle->SetExternalResource(cacheItem);
-        cacheItem->indexHandle.MakeWeak(cacheItem, QQuickVisualDataModelItemMetaType::release_index);
-
-        ++cacheItem->scriptRef;
-    }
+    if (model->m_cacheMetaType->constructor.IsEmpty())
+        model->m_cacheMetaType->initializeConstructor();
+    v8::Local<v8::Object> handle = model->m_cacheMetaType->constructor->NewInstance();
+    handle->SetExternalResource(cacheItem);
+    ++cacheItem->scriptRef;
 
-    return QQmlV8Handle::fromHandle(cacheItem->indexHandle);
+    return QQmlV8Handle::fromHandle(handle);
 }
 
 bool QQuickVisualDataGroupPrivate::parseIndex(
diff --git a/src/quick/items/qquickvisualdatamodel_p_p.h b/src/quick/items/qquickvisualdatamodel_p_p.h
index b88c8a4..e59b6dd 100644
--- a/src/quick/items/qquickvisualdatamodel_p_p.h
+++ b/src/quick/items/qquickvisualdatamodel_p_p.h
@@ -151,8 +151,6 @@ public:
     QObject *object;
     QQuickVisualDataModelAttached *attached;
     QVDMIncubationTask *incubationTask;
-    v8::Persistent<v8::Object> indexHandle;
-    v8::Persistent<v8::Value> modelHandle;
     int objectRef;
     int scriptRef;
     int groups;
-- 
2.7.4