Handle incremental diagnostics.

dart/site/try/src/editor.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 trydart.editor;
 
 import 'dart:html';
 
 import 'package:compiler/implementation/scanner/scannerlib.dart' show
     EOF_TOKEN,
     ErrorToken,
     StringScanner,
     Token;
 
 import 'ui.dart' show
     currentTheme,
     hackDiv,
+    interaction,
     mainEditorPane,
     observer,
     outputDiv;
 
 import 'decoration.dart' show
     CodeCompletionDecoration,
     Decoration,
     DiagnosticDecoration,
     error,
     info,
@@ skipping 117 matching lines @@
       CharacterData cdata = node;
       // print('walking: ${node.data}');
       if (anchorNode == node) {
         hasSelection = true;
         anchorOffset = selection.anchorOffset + offset;
       }
       int newOffset = offset + cdata.length;
       if (offset <= begin && begin < newOffset) {
         hasSelection = node == anchorNode;
         anchorOffset = selection.anchorOffset;
-        Node marker = new Text("");
-        node.replaceWith(marker);
-        // TODO(ahe): Don't highlight everything in the node.  Find the
-        // relevant token (works for now as we create a node for each token,
-        // which is probably not great for performance).
+        var alert;
         if (kind == 'error') {
-          marker.replaceWith(diagnostic(node, error(message)));
+          alert = error(message);
         } else if (kind == 'warning') {
-          marker.replaceWith(diagnostic(node, warning(message)));
+          alert = warning(message);
         } else {
-          marker.replaceWith(diagnostic(node, info(message)));
+          alert = info(message);
         }
-        if (hasSelection) {
-          selection.collapse(node, anchorOffset);
+        Element parent = node.parent;
+        if (parent.classes.contains("diagnostic") &&
+            !interaction.oldDiagnostics.contains(parent)) {
+          Element other = parent.lastChild;
+          other.remove();
+          SpanElement wrapper = new SpanElement();
+          wrapper.style
+              ..fontWeight = 'normal';
+          var root = getShadowRoot(wrapper);
+          if (root is ShadowRoot) {
+            // When https://code.google.com/p/chromium/issues/detail?id=313458
+            // is fixed:
+            // var link = new LinkElement()
+            //     ..rel = "stylesheet"
+            //     ..type = "text/css"
+            //     ..href = "dartlang-style.css";
+            // root.append(link);
+            root.append(
+                new StyleElement()..text = '@import url(dartlang-style.css)');
+          }
+          root
+              ..append(other)
+              ..append(alert);
+          other.style.display = 'block';
+          alert.style.display = 'block';
+          parent.append(wrapper);
+        } else {
+          if (interaction.oldDiagnostics.contains(parent)) {
+            node.remove();
+            parent.replaceWith(node);
+          }
+          Node marker = new Text("");
+          node.replaceWith(marker);
+          // TODO(ahe): Don't highlight everything in the node.  Find the
+          // relevant token (works for now as we create a node for each token,
+          // which is probably not great for performance).
+          marker.replaceWith(diagnostic(node, alert));
+          if (hasSelection) {
+            selection.collapse(node, anchorOffset);
+          }
         }
         foundNode = true;
         return;
       }
       offset = newOffset;
     } else if (type == Node.ELEMENT_NODE) {
       Element element = node;
       CssClassSet classes = element.classes;
       if (classes.contains('alert') ||
           classes.contains('dart-code-completion')) {
@@ skipping 56 matching lines @@
 
 diagnostic(text, tip) {
   if (text is String) {
     text = new Text(text);
   }
   return new AnchorElement()
       ..classes.add('diagnostic')
       ..append(text)
       ..append(tip);
 }