Reorder

mojo/services/view_manager/view_manager_connection.cc

Index: mojo/services/view_manager/view_manager_connection.cc
diff --git a/mojo/services/view_manager/view_manager_connection.cc b/mojo/services/view_manager/view_manager_connection.cc
index 8d4d0a6438ec31f1a7336fed2ddfdb1d7ab66464..0c724bd77638faf2d208dd9dbe71ac98c6b7e594 100644
--- a/mojo/services/view_manager/view_manager_connection.cc
+++ b/mojo/services/view_manager/view_manager_connection.cc
@@ -170,6 +170,23 @@ void ViewManagerConnection::ProcessNodeHierarchyChanged(
                                    NodesToINodes(to_send));
 }
 
+void ViewManagerConnection::ProcessNodeReorder(const Node* node,
+                                               const Node* relative_node,
+                                               OrderDirection direction,
+                                               Id server_change_id,
+                                               bool originated_change) {
+  if (originated_change ||
+      !known_nodes_.count(NodeIdToTransportId(node->id())) ||
+      !known_nodes_.count(NodeIdToTransportId(relative_node->id()))) {
+    return;
+  }
+
+  client()->OnNodeReordered(NodeIdToTransportId(node->id()),
+                            NodeIdToTransportId(relative_node->id()),
+                            direction,
+                            server_change_id);
+}
+
 void ViewManagerConnection::ProcessNodeViewReplaced(
     const Node* node,
     const View* new_view,
@@ -267,6 +284,36 @@ bool ViewManagerConnection::CanAddNode(const Node* parent,
   return (IsNodeDescendantOfRoots(child) || child->id().connection_id == id_);
 }
 
+bool ViewManagerConnection::CanReorderNode(const Node* node,
+                                           const Node* relative_node,
+                                           OrderDirection direction) const {
+  if (!node || !relative_node)
+    return false;
+
+  if (node->id().connection_id != id_)
+    return false;
+
+  const Node* parent = node->GetParent();
+  if (!parent || parent != relative_node->GetParent())
+    return false;
+
+  if (known_nodes_.count(NodeIdToTransportId(parent->id())) == 0)
+    return false;
+
+  std::vector<const Node*> children = parent->GetChildren();
+  const size_t child_i =
+      std::find(children.begin(), children.end(), node) - children.begin();
+  const size_t target_i =
+      std::find(children.begin(), children.end(), relative_node) -
+      children.begin();
+  if ((direction == ORDER_ABOVE && child_i == target_i + 1) ||
+      (direction == ORDER_BELOW && child_i + 1 == target_i)) {
+    return false;
+  }
+
+  return true;
+}
+
 bool ViewManagerConnection::CanDeleteNode(const NodeId& node_id) const {
   return node_id.connection_id == id_;
 }
@@ -553,6 +600,27 @@ void ViewManagerConnection::RemoveNodeFromParent(
   callback.Run(success);
 }
 
+void ViewManagerConnection::ReorderNode(Id node_id,
+                                        Id relative_node_id,
+                                        OrderDirection direction,
+                                        Id server_change_id,
+                                        const Callback<void(bool)>& callback) {
+  bool success = false;
+  if (server_change_id == root_node_manager_->next_server_change_id()) {
+    Node* node = GetNode(NodeIdFromTransportId(node_id));
+    Node* relative_node = GetNode(NodeIdFromTransportId(relative_node_id));
+    if (CanReorderNode(node, relative_node, direction)) {
+      success = true;
+      RootNodeManager::ScopedChange change(
+          this, root_node_manager_,
+          RootNodeManager::CHANGE_TYPE_ADVANCE_SERVER_CHANGE_ID, false);
+      node->GetParent()->Reorder(node, relative_node, direction);
+      root_node_manager_->ProcessNodeReorder(node, relative_node, direction);
+    }
+  }
+  callback.Run(success);
+}
+
 void ViewManagerConnection::GetNodeTree(
     Id node_id,
     const Callback<void(Array<INodePtr>)>& callback) {