Allow Observatory to run as a hosted web service

runtime/bin/vmservice/client/lib/src/elements/observatory_element.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.
 
 library observatory_element;
 
+import 'dart:async';
 import 'dart:html';
 import 'package:observatory/app.dart';
 import 'package:polymer/polymer.dart';
 
 /// Base class for all Observatory custom elements.
 @CustomTag('observatory-element')
 class ObservatoryElement extends PolymerElement {
   ObservatoryElement.created() : super.created();
 
+  ObservatoryApplication get app => ObservatoryApplication.app;
+
   @override
   void attached() {
     super.attached();
+    _startPoll();
   }
 
   @override
   void attributeChanged(String name, var oldValue, var newValue) {
     super.attributeChanged(name, oldValue, newValue);
   }
 
   @override
   void detached() {
     super.detached();
+    _stopPoll();
   }
 
+  @override
   void ready() {
     super.ready();
   }
 
-  void goto(MouseEvent event, var detail, Element target) {
-    location.onGoto(event, detail, target);
+  /// Set to a non-null value to enable polling on this element. When the poll
+  /// timer fires, onPoll will be called.
+  @observable Duration pollPeriod;
+  Timer _pollTimer;

[turnidge, 2014/07/01 00:27:47]

I wonder if there is a way to make this simpler.  Is it useful to have this
available to all ObservatoryElements?

[Cutch, 2014/07/01 17:14:51]

Perhaps it makes more sense on a pane-level. That being said, almost all dart:io
related elements auto-refresh. I could factor this out into an
PollingObservatoryElement if we don't want it on the base element itself.
Thoughts?

+
+  /// Called every [pollPeriod] while the element is attached to the DOM.
+  void onPoll() { }
+
+  void pollPeriodChanged(oldValue) {
+    if (pollPeriod != null) {
+      _startPoll();
+    } else {
+      _stopPoll();
+    }
   }
 
-  String gotoLink(String url) {
-    return location.makeLink(url);
+  void _startPoll() {
+    if (pollPeriod == null) {
+      return;
+    }
+    if (_pollTimer != null) {
+      _pollTimer.cancel();
+    }
+    _pollTimer = new Timer(pollPeriod, _onPoll);
   }
 
+  void _stopPoll() {
+    if (_pollTimer != null) {
+      _pollTimer.cancel();
+    }
+    _pollTimer = null;
+  }
 
+  void _onPoll() {
+    onPoll();
+    if (pollPeriod == null) {
+      // Stop polling.
+      _stopPoll();
+      return;
+    }
+    // Restart timer.
+    _pollTimer = new Timer(pollPeriod, _onPoll);
+  }
+
+  /// Utility method for handling on-click of <a> tags. Navigates
+  /// within the application using the [LocationManager].
+  void goto(MouseEvent event, var detail, Element target) {
+    app.locationManager.onGoto(event, detail, target);
+  }
+
+  /// Create a link that can be consumed by [goto].
+  String gotoLink(String url) {
+    return app.locationManager.makeLink(url);
+  }
 
   String formatTimePrecise(double time) => Utils.formatTimePrecise(time);
 
   String formatTime(double time) => Utils.formatTime(time);
 
   String formatSeconds(double x) => Utils.formatSeconds(x);
 
 
   String formatSize(int bytes) => Utils.formatSize(bytes);
 
@@ skipping 50 matching lines @@
               'Bool',
               'String',
               'Double',
               'Instance',
               'GrowableObjectArray',
               'Array',
               'Type',
               'Error'].contains(type));
   }
 }