mojo/services/ui/views/interfaces/view_manager.mojom

// Copyright 2015 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.

[DartPackage="mojo_services"]
module mojo.ui;

import "mojo/services/ui/views/interfaces/views.mojom";
import "mojo/services/ui/views/interfaces/view_associates.mojom";
import "mojo/services/ui/views/interfaces/view_trees.mojom";

// Maximum length for a view or view tree label.
const uint32 kLabelMaxLength = 32;

// The view manager is a service which manages trees of views.
//
// Before a view can be added to the view tree, it must first be registered
// with the view manager.  Once registered, the view receives a token as a
// transferable reference to be provided to the view's intended container.
[ServiceName="mojo::ui::ViewManager"]
interface ViewManager {
  // Registers a view with the view manager.
  //
  // When a view is registered, it receives its own host and a token
  // to identify it.
  //
  // The |view_host| is used to configure the view and interact with its
  // local environment.  The view host is private to the view and should
  // not be shared with anyone else.
  //
  // The |view_token| is used as a transferable reference which can
  // be passed to the view's intended container as part of a request to
  // add the view as a child.  The view manager itself does not describe
  // how this interaction should take place, only that the token should
  // eventually be passed back through the container's view host interface
  // as an argument to AddChild().
  //
  // The |label| is an optional name to associate with the view for
  // diagnostic purposes.  The label will be truncated if it is longer
  // than |kLabelMaxLength|.
  //
  // To unregister the view and cause it to be removed from the view tree,
  // simply close the |view| and/or |view_host| message pipes.
  RegisterView(mojo.ui.View view,
               mojo.ui.ViewHost& view_host,
               string? label) => (mojo.ui.ViewToken view_token);

  // Registers a view tree with the view manager.
  //
  // The |view_tree_host| is used to configure the view tree and interact
  // with the views it contains.  The view tree host is private to the view
  // and should not be shared with anyone else.
  //
  // The |label| is an optional name to associate with the view tree for
  // diagnostic purposes.  The label will be truncated if it is longer
  // than |kLabelMaxLength|.
  //
  // The |view_tree_token| is used as a transferable reference which can
  // be passed to trusted services to reference the view tree.
  //
  // To unregister the view tree simply close the |view_tree| and/or
  // |view_tree_host| message pipes.
  RegisterViewTree(mojo.ui.ViewTree view_tree,
                   mojo.ui.ViewTreeHost& view_tree_host,
                   string? label) => (mojo.ui.ViewTreeToken view_tree_token);
};