| // Copyright (c) 2016, 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. | |
| part of models; | |
| enum SentinelKind { | |
| /// Indicates that the object referred to has been collected by the GC. | |
| collected, | |
| /// Indicates that an object id has expired. | |
| expired, | |
| /// Indicates that a variable or field has not been initialized. | |
| notInitialized, | |
| /// Indicates that a variable has been eliminated by the optimizing compiler. | |
| optimizedOut, | |
| /// Reserved for future use. | |
| free, | |
| } | |
| abstract class Sentinel { | |
| /// What kind of sentinel is this? | |
| SentinelKind get kind; | |
| /// A reasonable string representation of this sentinel. | |
| String get valueAsString; | |
| } |