Converted Observatory refs elements

runtime/observatory/lib/src/elements/sentinel_value.dart

+// Copyright (c) 2013, 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.
+
+import 'dart:html';
+import 'dart:async';
+import 'package:observatory/models.dart' as M show Sentinel, SentinelKind;
+import 'package:observatory/src/elements/helpers/rendering_scheduler.dart';
+import 'package:observatory/src/elements/helpers/tag.dart';
+
+class SentinelValueElement extends HtmlElement implements Renderable {
+  static const tag = const Tag<SentinelValueElement>('sentinel-value');
+
+  RenderingScheduler<SentinelValueElement> _r;
+
+  Stream<RenderedEvent<SentinelValueElement>> get onRendered => _r.onRendered;
+
+  M.Sentinel _sentinel;
+
+  M.Sentinel get sentinel => _sentinel;
+
+  factory SentinelValueElement(M.Sentinel sentinel, {RenderingQueue queue}) {
+    assert(sentinel != null);
+    SentinelValueElement e = document.createElement(tag.name);
+    e._r = new RenderingScheduler(e, queue: queue);
+    e._sentinel = sentinel;
+    return e;
+  }
+
+  SentinelValueElement.created() : super.created();
+
+  @override
+  void attached() {
+    super.attached();
+    _r.enable();
+  }
+
+  @override
+  void detached() {
+    super.detached();
+    _r.disable(notify: true);
+    text = '';
+    title = '';
+  }
+
+  void render() {
+    text = _sentinel.valueAsString;
+    title = _sentinelKindToDescription(_sentinel.kind);
+  }
+
+  static String _sentinelKindToDescription(M.SentinelKind kind) {
+    switch (kind) {
+      case M.SentinelKind.collected:
+        return 'This object has been reclaimed by the garbage collector.';
+      case M.SentinelKind.expired:
+        return 'The handle to this object has expired. '
+               'Consider refreshing the page.';
+      case M.SentinelKind.notInitialized:
+        return 'This object will be initialized once it is accessed by '
+               'the program.';
+      case M.SentinelKind.beingInitialized:
+        return 'This object is currently being initialized.';
+      case M.SentinelKind.optimizedOut:
+        return 'This object is no longer needed and has been removed by the '
+               'optimizing compiler.';
+      case M.SentinelKind.free:
+        return '';
+    }
+    throw new Exception('Unknown SentinelKind: $kind');
+  }
+
+}