Add error condition INVALID_OVERLAY_CHANGE to analysis server.

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 'package:analyzer/file_system/file_system.dart';
@@ skipping 479 matching lines @@
     } on UnimplementedError catch (e) {
       throw new RequestFailure(
                   new Response.unsupportedFeature(
                       requestId, e.message));
     }
   }
 
   /**
    * Implementation for `analysis.updateContent`.
    */
-  void updateContent(Map<String, dynamic> changes) {
+  void updateContent(String id, Map<String, dynamic> changes) {
     changes.forEach((file, change) {
       AnalysisContext analysisContext = getAnalysisContext(file);
       // TODO(paulberry): handle the case where a file is referred to by more
       // than one context (e.g package A depends on package B using a local
       // path, user has both packages open for editing in separate contexts,
       // and user modifies a file in package B).
       if (analysisContext != null) {
         Source source = getSource(file);
         if (change is AddContentOverlay) {
           analysisContext.setContents(source, change.content);
         } else if (change is ChangeContentOverlay) {
           // TODO(paulberry): an error should be generated if source is not
           // currently in the content cache.
           TimestampedData<String> oldContents = analysisContext.getContents(
               source);
-          String newContents = SourceEdit.applySequence(oldContents.data, change.edits);
+          String newContents;
+          try {
+            newContents = SourceEdit.applySequence(oldContents.data,
+                change.edits);
+          } on RangeError {
+            throw new RequestFailure(new Response(id, error: new RequestError(
+                RequestErrorCode.INVALID_OVERLAY_CHANGE,
+                'Invalid overlay change')));
+          }
           // TODO(paulberry): to aid in incremental processing it would be
           // better to use setChangedContents.
           analysisContext.setContents(source, newContents);
         } else if (change is RemoveContentOverlay) {
           analysisContext.setContents(source, null);
         } else {
           // Protocol parsing should have ensured that we never get here.
           throw new AnalysisException('Illegal change type');
         }
         schedulePerformAnalysisOperation(analysisContext);
@@ skipping 322 matching lines @@
       stackTraceString = 'null stackTrace';
     }
     // send the notification
     channel.sendNotification(new ServerErrorParams(true, exceptionString,
         stackTraceString).toNotification());
   }
 }
 
 
 typedef void OptionUpdater(AnalysisOptionsImpl options);