Add minimal support for sending notifications

pkg/analyzer_plugin/lib/plugin/plugin.dart

 // 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 'dart:async';
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/physical_file_system.dart';
 import 'package:analyzer/src/dart/analysis/byte_store.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart'
@@ skipping 409 matching lines @@
    */
   void onDone() {}
 
   /**
    * The method that is called when an error has occurred in the analysis
    * server. This method will not be invoked under normal conditions.
    */
   void onError(Object exception, StackTrace stackTrace) {}
 
   /**
-   * Send notifications corresponding to the given description of subscriptions.
-   * The map is keyed by the path of each file for which notifications should be
-   * sent and has values representing the list of services associated with the
-   * notifications to send.
+   * If the plugin provides folding information, send a folding notification
+   * for the file with the given [path] to the server.
+   */
+  Future<Null> sendFoldingNotification(String path) {
+    return new Future.value();
+  }
+
+  /**
+   * If the plugin provides highlighting information, send a highlights
+   * notification for the file with the given [path] to the server.
+   */
+  Future<Null> sendHighlightsNotification(String path) {
+    return new Future.value();
+  }
+
+  /**
+   * If the plugin provides navigation information, send a navigation
+   * notification for the file with the given [path] to the server.
+   */
+  Future<Null> sendNavigationNotification(String path) {
+    return new Future.value();
+  }
+
+  /**
+   * Send notifications for the services subscribed to for the file with the
+   * given [path].
+   *
+   * This is a convenience method that subclasses can use to send notifications
+   * after analysis has been performed on a file.
+   */
+  void sendNotificationsForFile(String path) {
+    for (AnalysisService service in subscriptionManager.servicesForFile(path)) {
+      _sendNotificationForFile(path, service);
+    }
+  }
+
+  /**
+   * Send notifications corresponding to the given description of
+   * [subscriptions]. The map is keyed by the path of each file for which
+   * notifications should be sent and has values representing the list of
+   * services associated with the notifications to send.
+   *
+   * This method is used when the set of subscribed notifications has been
+   * changed and notifications need to be sent even when the specified files
+   * have already been analyzed.
    */
   void sendNotificationsForSubscriptions(
-      Map<String, List<AnalysisService>> subscriptions);
+      Map<String, List<AnalysisService>> subscriptions) {
+    subscriptions.forEach((String path, List<AnalysisService> services) {
+      for (AnalysisService service in services) {
+        _sendNotificationForFile(path, service);
+      }
+    });
+  }
+
+  /**
+   * If the plugin provides occurrences information, send an occurrences
+   * notification for the file with the given [path] to the server.
+   */
+  Future<Null> sendOccurrencesNotification(String path) {
+    return new Future.value();
+  }
+
+  /**
+   * If the plugin provides outline information, send an outline notification
+   * for the file with the given [path] to the server.
+   */
+  Future<Null> sendOutlineNotification(String path) {
+    return new Future.value();
+  }
 
   /**
    * Start this plugin by listening to the given communication [channel].
    */
   void start(PluginCommunicationChannel channel) {
     _channel = channel;
     _channel.listen(_onRequest, onError: onError, onDone: onDone);
   }
 
   /**
@@ skipping 108 matching lines @@
     } catch (exception, stackTrace) {
       response = new Response(id, requestTime,
           error: new RequestError(
               RequestErrorCode.PLUGIN_ERROR, exception.toString(),
               stackTrace: stackTrace.toString()));
     }
     if (response != null) {
       _channel.sendResponse(response);
     }
   }
+
+  /**
+   * Send a notification for the file at the given [path] corresponding to the
+   * given [service].
+   */
+  void _sendNotificationForFile(String path, AnalysisService service) {
+    switch (service) {
+      case AnalysisService.FOLDING:
+        sendFoldingNotification(path);
+        break;
+      case AnalysisService.HIGHLIGHTS:
+        sendHighlightsNotification(path);
+        break;
+      case AnalysisService.NAVIGATION:
+        sendNavigationNotification(path);
+        break;
+      case AnalysisService.OCCURRENCES:
+        sendOccurrencesNotification(path);
+        break;
+      case AnalysisService.OUTLINE:
+        sendOutlineNotification(path);
+        break;
+    }
+  }
 }