Fix memory leaks in CollectionObject by making ob a weak pointer and removing prev pointer.

Something was cyclic in CollectionObject and we don't traverse backwards anyways

code/AssetLib/Blender/BlenderLoader.cpp

@@ -325,7 +325,7 @@ void BlenderImporter::ParseSubCollection(const Blender::Scene &in, aiNode *root,
     // Count number of objects
     for (std::shared_ptr<CollectionObject> cur = std::static_pointer_cast<CollectionObject>(collection->gobject.first); cur; cur = cur->next) {
         if (cur->ob) {
-            root_objects.push_back(cur->ob.get());
+            root_objects.push_back(cur->ob);
         }
     }
     std::deque<Collection *> root_children;

code/AssetLib/Blender/BlenderScene.cpp

@@ -100,9 +100,18 @@ void Structure::Convert<CollectionObject>(
         CollectionObject &dest,
         const FileDatabase &db) const {
 
-    ReadFieldPtr<ErrorPolicy_Fail>(dest.prev, "*prev", db);
     ReadFieldPtr<ErrorPolicy_Fail>(dest.next, "*next", db);
-    ReadFieldPtr<ErrorPolicy_Igno>(dest.ob, "*ob", db);
+    {
+        //std::shared_ptr<CollectionObject> prev;
+        //ReadFieldPtr<ErrorPolicy_Fail>(prev, "*prev", db);
+        //dest.prev = prev.get();
+
+        std::shared_ptr<Object> ob;
+        ReadFieldPtr<ErrorPolicy_Igno>(ob, "*ob", db);
+        dest.ob = ob.get();
+    }
+
+    db.reader->IncPtr(size);
 }
 
 //--------------------------------------------------------------------------------

code/AssetLib/Blender/BlenderScene.h

@@ -107,6 +107,7 @@ namespace Blender {
 struct Object;
 struct MTex;
 struct Image;
+struct Collection;
 
 #include <memory>
 
@@ -147,18 +148,11 @@ struct Group : ElemBase {
     std::shared_ptr<GroupObject> gobject;
 };
 
-// -------------------------------------------------------------------------------
-struct Collection : ElemBase {
-    ID id FAIL;
-    ListBase gobject; // CollectionObject
-    ListBase children; // CollectionChild
-    //ListBase objects; // Objects
-};
-
 // -------------------------------------------------------------------------------
 struct CollectionObject : ElemBase {
-    std::shared_ptr<CollectionObject> next, prev;
-    std::shared_ptr<Object> ob;
+    //CollectionObject* prev;
+    std::shared_ptr<CollectionObject> next;
+    Object *ob;
 };
 
 // -------------------------------------------------------------------------------
@@ -167,6 +161,13 @@ struct CollectionChild : ElemBase {
     std::shared_ptr<Collection> collection;
 };
 
+// -------------------------------------------------------------------------------
+struct Collection : ElemBase {
+    ID id FAIL;
+    ListBase gobject; // CollectionObject
+    ListBase children; // CollectionChild
+};
+
 // -------------------------------------------------------------------------------
 struct World : ElemBase {
     ID id FAIL;