Only send "analysis.analyzedFiles" notification when the set of files changes.

pkg/analysis_server/lib/src/analysis_server.dart

 // Copyright (c) 2014, 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 analysis.server;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:core' hide Resource;
 import 'dart:math' show max;
@@ skipping 239 matching lines @@
    * content cache for all contexts.
    */
   final ContentCache overlayState = new ContentCache();
 
   /**
    * The plugins that are defined outside the analysis_server package.
    */
   List<Plugin> userDefinedPlugins;
 
   /**
+   * If the "analysis.analyzedFiles" notification is currently being subscribed
+   * to (see [generalAnalysisServices]), and at least one such notification has
+   * been sent since the subscription was enabled, the set of analyzed files
+   * that was delivered in the most recently sent notification.  Otherwise
+   * `null`.
+   */
+  Set<String> prevAnalyzedFiles;
+
+  /**
    * Initialize a newly created server to receive requests from and send
    * responses to the given [channel].
    *
    * If a [contextManager] is provided, then the [packageResolverProvider] will
    * be ignored.
    *
    * If [rethrowExceptions] is true, then any exceptions thrown by analysis are
    * propagated up the call stack.  The default is true to allow analysis
    * exceptions to show up in unit tests, but it should be set to false when
    * running a full analysis server.
@@ skipping 693 matching lines @@
    * Implementation for `analysis.setGeneralSubscriptions`.
    */
   void setGeneralAnalysisSubscriptions(
       List<GeneralAnalysisService> subscriptions) {
     Set<GeneralAnalysisService> newServices = subscriptions.toSet();
     if (newServices.contains(GeneralAnalysisService.ANALYZED_FILES) &&
         !generalAnalysisServices
             .contains(GeneralAnalysisService.ANALYZED_FILES) &&
         isAnalysisComplete()) {
       sendAnalysisNotificationAnalyzedFiles(this);
+    } else if (!newServices.contains(GeneralAnalysisService.ANALYZED_FILES) &&
+        generalAnalysisServices
+            .contains(GeneralAnalysisService.ANALYZED_FILES)) {
+      prevAnalyzedFiles = null;
     }
     generalAnalysisServices = newServices;
   }
 
   /**
    * Set the priority files to the given [files].
    */
   void setPriorityFiles(String requestId, List<String> files) {
     // Note: when a file is a priority file, that information needs to be
     // propagated to all contexts that analyze the file, so that all contexts
@@ skipping 569 matching lines @@
   /**
    * The [PerformanceTag] for time spent in server request handlers.
    */
   static PerformanceTag serverRequests = new PerformanceTag('serverRequests');
 
   /**
    * The [PerformanceTag] for time spent in split store microtasks.
    */
   static PerformanceTag splitStore = new PerformanceTag('splitStore');
 }