Add support for highlights notification

pkg/analyzer_plugin/lib/utilities/highlights/highlights.dart

Index: pkg/analyzer_plugin/lib/utilities/highlights/highlights.dart
diff --git a/pkg/analyzer_plugin/lib/utilities/highlights/highlights.dart b/pkg/analyzer_plugin/lib/utilities/highlights/highlights.dart
new file mode 100644
index 0000000000000000000000000000000000000000..0940faeb31cd26f3b815035e9dd22dfedbbdcd89
--- /dev/null
+++ b/pkg/analyzer_plugin/lib/utilities/highlights/highlights.dart
@@ -0,0 +1,116 @@
+// Copyright (c) 2017, 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 'package:analyzer/dart/analysis/results.dart';
+import 'package:analyzer/file_system/file_system.dart';
+import 'package:analyzer/src/generated/source.dart';
+import 'package:analyzer_plugin/protocol/protocol.dart';
+import 'package:analyzer_plugin/protocol/protocol_common.dart';
+import 'package:analyzer_plugin/protocol/protocol_generated.dart';
+import 'package:analyzer_plugin/src/utilities/highlights/highlights.dart';
+import 'package:analyzer_plugin/utilities/generator.dart';
+
+/**
+ * The information about a requested set of highlight regions when computing
+ * highlight regions in a `.dart` file.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class DartHighlightsRequest implements HighlightsRequest {
+  /**
+   * The analysis result for the file for which the highlight regions are being
+   * requested.
+   */
+  ResolveResult get result;
+}
+
+/**
+ * An object that [HighlightsContributor]s use to record highlight regions.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class HighlightsCollector {
+  /**
+   * Add a highlight region corresponding to the given source [range] whose type
+   * is the given [type].
+   */
+  void addRange(SourceRange range, HighlightRegionType type);
+
+  /**
+   * Add a highlight region starting at the given [offset] and having the given
+   * [length] whose type is the given [type].
+   */
+  void addRegion(int offset, int length, HighlightRegionType type);
+}
+
+/**
+ * An object used to produce highlight regions.
+ *
+ * Clients may implement this class when implementing plugins.
+ */
+abstract class HighlightsContributor {
+  /**
+   * Contribute highlight regions into the given [collector].
+   */
+  void computeHighlights(
+      HighlightsRequest request, HighlightsCollector collector);
+}
+
+/**
+ * A generator that will generate an 'analysis.highlights' notification.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+class HighlightsGenerator {
+  /**
+   * The contributors to be used to generate the highlight regions.
+   */
+  final List<HighlightsContributor> contributors;
+
+  /**
+   * Initialize a newly created highlights generator to use the given
+   * [contributors].
+   */
+  HighlightsGenerator(this.contributors);
+
+  /**
+   * Create an 'analysis.highlights' notification. If any of the contributors
+   * throws an exception, also create a non-fatal 'plugin.error' notification.
+   */
+  GeneratorResult generateHighlightsNotification(HighlightsRequest request) {
+    List<Notification> notifications = <Notification>[];
+    HighlightsCollectorImpl collector = new HighlightsCollectorImpl();
+    for (HighlightsContributor contributor in contributors) {
+      try {
+        contributor.computeHighlights(request, collector);
+      } catch (exception, stackTrace) {
+        notifications.add(new PluginErrorParams(
+                false, exception.toString(), stackTrace.toString())
+            .toNotification());
+      }
+    }
+    notifications.add(
+        new AnalysisHighlightsParams(request.path, collector.regions)
+            .toNotification());
+    return new GeneratorResult(null, notifications);
+  }
+}
+
+/**
+ * The information about a requested set of highlight regions.
+ *
+ * Clients may not extend, implement or mix-in this class.
+ */
+abstract class HighlightsRequest {
+  /**
+   * Return the path of the file for which highlight regions are being
+   * requested.
+   */
+  String get path;
+
+  /**
+   * Return the resource provider associated with this request.
+   */
+  ResourceProvider get resourceProvider;
+}