Wrapping leaf nodes in non polymer elements

runtime/observatory/lib/src/elements/isolate_ref_wrapper.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/service_html.dart' show Isolate;
+import 'package:observatory/repositories.dart' show IsolateUpdateEvent;
+import 'shims/binding.dart';
+import 'helpers/tag.dart';
+import 'isolate_ref.dart';
+
+class IsolateRefElementWrapper extends HtmlElement {
+
+  static final binder = new Binder<IsolateRefElementWrapper>(
+    const [const Binding('ref')]);
+
+  static const tag = const Tag<IsolateRefElementWrapper>('isolate-ref');
+
+  final StreamController<IsolateUpdateEvent> _updatesController =
+    new StreamController<IsolateUpdateEvent>();
+  Stream<IsolateUpdateEvent> _updates;
+  StreamSubscription _subscription;
+
+  Isolate _isolate;
+  Isolate get ref => _isolate;
+  void set ref(Isolate ref) { _isolate = ref; _detached(); _attached(); }
+
+  IsolateRefElementWrapper.created() : super.created() {
+    _updates = _updatesController.stream.asBroadcastStream();
+    binder.registerCallback(this);
+    createShadowRoot();
+    render();
+  }
+
+  @override
+  void attached() {
+    super.attached();
+    _attached();
+  }
+
+  void _attached() {
+    if (ref != null) {
+      _subscription = ref.changes.listen((_) {
+        _updatesController.add(new IsolateUpdateEvent(ref));

[Cutch, 2016/07/07 19:50:57]

This pattern is going to appear often. Maybe subscribing for updates and
unsubscribing for updates could be factored into utility functions?

[cbernaschina, 2016/07/07 22:08:13]

Working on it.

+      });
+    }
+    render();
+  }
+
+  @override
+  void detached() {
+    super.detached();
+    _detached();
+  }
+
+  void _detached() {
+    if (_subscription != null) {
+      _subscription.cancel();
+      _subscription = null;
+    }
+  }
+
+  void render() {
+    shadowRoot.children = [];
+    if (ref == null) return;
+
+    shadowRoot.children = [
+      new IsolateRefElement(_isolate, _updates)
+    ];
+  }
+}