Introduces another change id to hierarchy mutations

mojo/services/view_manager/root_node_manager.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_VIEW_MANAGER_ROOT_NODE_MANAGER_H_
 #define MOJO_SERVICES_VIEW_MANAGER_ROOT_NODE_MANAGER_H_
 
 #include <map>
 
 #include "base/basictypes.h"
@@ skipping 10 matching lines @@
 namespace services {
 namespace view_manager {
 
 class View;
 class ViewManagerConnection;
 
 // RootNodeManager is responsible for managing the set of ViewManagerConnections
 // as well as providing the root of the node hierarchy.
 class MOJO_VIEW_MANAGER_EXPORT RootNodeManager : public NodeDelegate {
  public:
+  // Used to indicate if the server id should be incremented after notifiying
+  // clients of the change.
+  enum ChangeType {
+    CHANGE_TYPE_ADVANCE_SERVER_CHANGE_ID,
+    CHANGE_TYPE_DONT_ADVANCE_SERVER_CHANGE_ID,
+  };
+
   // Create when a ViewManagerConnection is about to make a change. Ensures
   // clients are notified of the correct change id.
   class ScopedChange {
    public:
     ScopedChange(ViewManagerConnection* connection,
                  RootNodeManager* root,
-                 TransportChangeId change_id);
+                 TransportChangeId change_id,
+                 RootNodeManager::ChangeType change_type);
     ~ScopedChange();
 
    private:
     RootNodeManager* root_;
+    const ChangeType change_type_;
 
     DISALLOW_COPY_AND_ASSIGN(ScopedChange);
   };
 
   explicit RootNodeManager(Shell* shell);
   virtual ~RootNodeManager();
 
   // Returns the id for the next ViewManagerConnection.
   TransportConnectionId GetAndAdvanceNextConnectionId();
 
+  TransportChangeId next_server_change_id() const {
+    return next_server_change_id_;
+  }
+
   void AddConnection(ViewManagerConnection* connection);
   void RemoveConnection(ViewManagerConnection* connection);
 
   // Returns the connection by id.
   ViewManagerConnection* GetConnection(TransportConnectionId connection_id);
 
   // Returns the Node identified by |id|.
   Node* GetNode(const NodeId& id);
 
   // Returns the View identified by |id|.
@@ skipping 13 matching lines @@
 
  private:
   // Used to setup any static state needed by RootNodeManager.
   struct Context {
     Context();
     ~Context();
   };
 
   // Tracks a change.
   struct Change {
-    Change(TransportConnectionId connection_id, TransportChangeId change_id)
+    Change(TransportConnectionId connection_id,
+           TransportChangeId client_change_id)
         : connection_id(connection_id),
-          change_id(change_id) {
+          client_change_id(client_change_id) {
     }
 
     TransportConnectionId connection_id;
-    TransportChangeId change_id;
+    TransportChangeId client_change_id;
   };
 
   typedef std::map<TransportConnectionId, ViewManagerConnection*> ConnectionMap;
 
   // Invoked when a particular connection is about to make a change. Records
   // the |change_id| so that it can be supplied to the clients by way of
   // OnNodeHierarchyChanged().
   // Changes should never nest, meaning each PrepareForChange() must be
   // balanced with a call to FinishChange() with no PrepareForChange()
   // in between.
   void PrepareForChange(ViewManagerConnection* connection,
                         TransportChangeId change_id);
 
   // Balances a call to PrepareForChange().
-  void FinishChange();
+  void FinishChange(ChangeType change_type);
+
+  TransportChangeId GetClientChangeId(
+      TransportConnectionId connection_id) const;
 
   // Overriden from NodeDelegate:
   virtual void OnNodeHierarchyChanged(const NodeId& node,
                                       const NodeId& new_parent,
                                       const NodeId& old_parent) OVERRIDE;
   virtual void OnNodeViewReplaced(const NodeId& node,
                                   const ViewId& new_view_id,
                                   const ViewId& old_view_id) OVERRIDE;
 
   Context context_;
 
   // ID to use for next ViewManagerConnection.
   TransportConnectionId next_connection_id_;
 
+  TransportChangeId next_server_change_id_;
+
   // Set of ViewManagerConnections.
   ConnectionMap connection_map_;
 
   // If non-null we're processing a change.
   scoped_ptr<Change> change_;
 
   RootViewManager root_view_manager_;
 
   // Root node.
   Node root_;
 
   DISALLOW_COPY_AND_ASSIGN(RootNodeManager);
 };
 
 }  // namespace view_manager
 }  // namespace services
 }  // namespace mojo
 
 #endif  // MOJO_SERVICES_VIEW_MANAGER_ROOT_NODE_MANAGER_H_