First step at setroots

mojo/services/public/interfaces/view_manager/view_manager.mojom

 // 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.
 
 module mojo.view_manager {
 
 struct INode {
   uint32 parent_id;
   uint32 node_id;
   uint32 view_id;
@@ skipping 21 matching lines @@
   // are sent as a result of this. Only the connection that created the node can
   // delete it.
   DeleteNode(uint32 node_id) => (bool success);
 
   // Reparents a node. See description above class for details of |change_id|.
   // This fails for any of the following reasons:
   // . |server_change_id| is not the expected id.
   // . |parent| or |child| does not identify a valid node.
   // . |child| is an ancestor of |parent|.
   // . |child| is already a child of |parent|.
+  //
+  // This may result in a connection getting OnNodeDeleted(). See
+  // RemoveNodeFromParent for details.
   AddNode(uint32 parent,
           uint32 child,
           uint32 server_change_id) => (bool success);
 
   // Removes a view from its current parent. See description above class for
   // details of |change_id|. This fails if the node is not valid,
   // |server_change_id| doesn't match, or the node already has no parent.
+  //
+  // Removing a node from a parent may result in OnNodeDeleted() being sent to
+  // other connections. For example, connection A has nodes 1 and 2, with 2 a
+  // child of 1. Connection B has a root 1. If 2 is removed from 1 then B gets
+  // OnNodeDeleted(). This is done as node 2 is effectively no longer visible to
+  // connection B.
   RemoveNodeFromParent(uint32 node_id,
                        uint32 server_change_id) => (bool success);
 
   // Returns the nodes comprising the tree starting at |node_id|. |node_id| is 
   // the first result in the return value, unless |node_id| is invalid, in which
   // case an empty vector is returned. The nodes are visited using a depth first
   // search (pre-order).
   GetNodeTree(uint32 node_id) => (INode[] nodes);
 
   // Creates a new view with the specified id. It is up to the client to ensure
   // the id is unique to the connection (the id need not be globally unique).
   // Additionally the connection id (embedded in |view_id|) must match that of
   // the connection.
   CreateView(uint32 view_id) => (bool success);
 
   // Deletes the view with the specified id. Only the connection that created
   // the view can delete it.
   DeleteView(uint32 view_id) => (bool success);
 
   // Sets the view a node is showing.
   SetView(uint32 node_id, uint32 view_id) => (bool success);
 
   // Shows the specified image (png encoded) in the specified view.
   SetViewContents(uint32 view_id,
                   handle<shared_buffer> buffer,
                   uint32 buffer_size);
+
+  // Sets the ids of the roots for the specified connection.
+  // TODO(sky): this is temporary for testing. This needs to be conveyed at
+  // creation time of a new connection.
+  SetRoots(uint16 connection_id, uint32[] nodes) => (bool success);
 };
 
 // Changes to nodes/views are not sent to the connection that originated the
 // change. For example, if connection 1 attaches a view to a node (SetView())
 // connection 1 does not receive OnNodeViewReplaced().
 interface IViewManagerClient {
   // Invoked once the connection has been established. |connection_id| is the id
   // that uniquely identifies this connection. |next_server_change_id| is the
   // id of the next change the server is expecting. |nodes| are the nodes
   // parented to the root.
@@ skipping 26 matching lines @@
 
   // Invoked when the view associated with a node is replaced by another view.
   // 0 is used to identify a null view.
   OnNodeViewReplaced(uint32 node, uint32 new_view_id, uint32 old_view_id);
 
   // Invoked when a view is deleted.
   OnViewDeleted(uint32 view);
 };
 
 }