| // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| /** |
| * Encapsulates the field [TreeElementMixin._element]. |
| * |
| * This library is an implementation detail of dart2js, and should not |
| * be imported except by resolution and tree node libraries, or for |
| * testing. |
| * |
| * We have taken great care to ensure AST nodes can be cached between |
| * compiler instances. Part of this requires that we always access |
| * resolution results through TreeElements. |
| * |
| * So please, do not add additional elements to this library, and do |
| * not import it. |
| */ |
| library dart2js.resolution.secret_tree_element; |
| |
| import '../common.dart'; |
| |
| /// Interface for associating |
| abstract class TreeElementMixin { |
| Object get _element; |
| void set _element(Object value); |
| } |
| |
| /// Null implementation of [TreeElementMixin] which does not allow association |
| /// of elements. |
| /// |
| /// This class is the superclass of all AST nodes. |
| abstract class NullTreeElementMixin implements TreeElementMixin, Spannable { |
| |
| // Deliberately using [Object] here to thwart code completion. |
| // You're not really supposed to access this field anyways. |
| Object get _element => null; |
| set _element(_) { |
| assert(invariant(this, false, |
| message: "Elements cannot be associated with ${runtimeType}.")); |
| } |
| } |
| |
| /// Actual implementation of [TreeElementMixin] which stores the associated |
| /// element in the private field [_element]. |
| /// |
| /// This class is mixed into the node classes that are actually associated with |
| /// elements. |
| abstract class StoredTreeElementMixin implements TreeElementMixin { |
| Object _element; |
| } |
| |
| /** |
| * Do not call this method directly. Instead, use an instance of |
| * TreeElements. |
| * |
| * Using [Object] as return type to thwart code completion. |
| */ |
| Object getTreeElement(TreeElementMixin node) => node._element; |
| |
| /** |
| * Do not call this method directly. Instead, use an instance of |
| * TreeElements. |
| */ |
| void setTreeElement(TreeElementMixin node, Object value) { |
| node._element = value; |
| } |