Deletion/ownership

mojo/services/public/cpp/view_manager/view_tree_node.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_VIEW_TREE_NODE_H_
 #define MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_VIEW_TREE_NODE_H_
 
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/observer_list.h"
 #include "mojo/services/public/cpp/view_manager/view_manager_types.h"
 
 namespace mojo {
 namespace services {
 namespace view_manager {
 
 class ViewManager;
 class ViewTreeNodeObserver;
 
+// ViewTreeNodes are owned by the ViewManager.
+// TODO(beng): Right now, you'll have to implement a ViewTreeNodeObserver to
+//             track destruction and NULL any pointers you have.
+//             Investigate some kind of smart pointer or weak pointer for these.
 class ViewTreeNode {
  public:
   typedef std::vector<ViewTreeNode*> Children;
 
-  explicit ViewTreeNode(ViewManager* manager);
-  ViewTreeNode();  // Used for tests.
-  ~ViewTreeNode();
+  static ViewTreeNode* Create(ViewManager* view_manager);
+
+  // Destroys this node and all its children.
+  void Destroy();
 
   // Configuration.
   TransportNodeId id() const { return id_; }
-  void set_owned_by_parent(bool owned_by_parent) {
-    owned_by_parent_ = owned_by_parent;
-  }
 
   // Observation.
   void AddObserver(ViewTreeNodeObserver* observer);
   void RemoveObserver(ViewTreeNodeObserver* observer);
 
   // Tree.
   ViewTreeNode* parent() { return parent_; }
   const ViewTreeNode* parent() const { return parent_; }
   const Children& children() const { return children_; }
 
   void AddChild(ViewTreeNode* child);
   void RemoveChild(ViewTreeNode* child);
 
   bool Contains(ViewTreeNode* child) const;
 
   ViewTreeNode* GetChildById(TransportNodeId id);
 
+ protected:
+  // This class is subclassed only by test classes that provide a public ctor.
+  ViewTreeNode();
+  ~ViewTreeNode();
+
  private:
   friend class ViewTreeNodePrivate;
 
+  explicit ViewTreeNode(ViewManager* manager);
+
+  void LocalDestroy();
   void LocalAddChild(ViewTreeNode* child);
   void LocalRemoveChild(ViewTreeNode* child);
 
   ViewManager* manager_;
   TransportNodeId id_;
-  bool owned_by_parent_;
   ViewTreeNode* parent_;
   Children children_;
 
   ObserverList<ViewTreeNodeObserver> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(ViewTreeNode);
 };
 
 }  // namespace view_manager
 }  // namespace services
 }  // namespace mojo
 
 #endif  // MOJO_SERVICES_PUBLIC_CPP_VIEW_MANAGER_VIEW_TREE_NODE_H_