Discard pending notifications on the same source change.

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:math' show max;
 
@@ skipping 316 matching lines @@
 
   /**
    * There was an error related to the socket from which requests are being
    * read.
    */
   void error(argument) {
     running = false;
   }
 
   /**
+   * Performs all scheduled analysis operations.
+   */
+  void test_performAllAnalysisOperations() {
+    while (true) {
+      ServerOperation operation = operationQueue.takeIf((operation) {
+        return operation is PerformAnalysisOperation;
+      });
+      if (operation == null) {
+        break;
+      }
+      operation.perform(this);
+    }
+  }
+
+  /**
    * If the given notice applies to a file contained within an analysis root,
    * notify interested parties that the file has been (at least partially)
    * analyzed.
    */
   void fileAnalyzed(ChangeNotice notice) {
     if (contextDirectoryManager.isInAnalysisRoot(notice.source.fullName)) {
       _onFileAnalyzedController.add(notice);
     }
   }
 
@@ skipping 593 matching lines @@
       dartEntry.flushAstStructures();
     }
   }
 
   /**
    * Implementation for `analysis.updateContent`.
    */
   void updateContent(String id, Map<String, dynamic> changes) {
     changes.forEach((file, change) {
       Source source = getSource(file);
+      operationQueue.sourceAboutToChange(source);
+      // Prepare the new contents.
       String oldContents = _overlayState.getContents(source);
       String newContents;
       if (change is AddContentOverlay) {
         newContents = change.content;
       } else if (change is ChangeContentOverlay) {
         if (oldContents == null) {
           // The client may only send a ChangeContentOverlay if there is
           // already an existing overlay for the source.
           throw new RequestFailure(
               new Response(
@@ skipping 301 matching lines @@
           new DateTime.now().millisecondsSinceEpoch -
           request.clientRequestTime;
       requestLatency += latency;
       maxLatency = max(maxLatency, latency);
       if (latency > 150) {
         ++slowRequestCount;
       }
     }
   }
 }