allow client to specify any combination of add/modified/removed

pkg/analysis_server/lib/src/domain_context.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 domain.context;
 
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
@@ skipping 136 matching lines @@
     return response;
   }
 
   /**
    * Convert the given JSON object into a [ChangeSet], using the given
    * [sourceFactory] to convert the embedded strings into sources.
    */
   ChangeSet createChangeSet(Request request, SourceFactory sourceFactory,
                             RequestDatum jsonData) {
     ChangeSet changeSet = new ChangeSet();
-    convertSources(request, sourceFactory, jsonData[ADDED_PARAM], (Source source) {
-      changeSet.addedSource(source);
-    });
-    convertSources(request, sourceFactory, jsonData[MODIFIED_PARAM], (Source source) {
-      changeSet.changedSource(source);
-    });
-    convertSources(request, sourceFactory, jsonData[REMOVED_PARAM], (Source source) {
-      changeSet.removedSource(source);
-    });
+    if (jsonData.hasKey(ADDED_PARAM)) {
+      convertSources(request, sourceFactory, jsonData[ADDED_PARAM], (Source source) {
+        changeSet.addedSource(source);
+      });
+    }
+    if (jsonData.hasKey(MODIFIED_PARAM)) {
+      convertSources(request, sourceFactory, jsonData[MODIFIED_PARAM], (Source source) {
+        changeSet.changedSource(source);
+      });
+    }
+    if (jsonData.hasKey(REMOVED_PARAM)) {
+      convertSources(request, sourceFactory, jsonData[REMOVED_PARAM], (Source source) {
+        changeSet.removedSource(source);
+      });
+    }
     return changeSet;
   }
 
   /**
    * If the given [sources] is a list of strings, use the given [sourceFactory]
    * to convert each string into a source and pass the source to the given
    * [handler]. Otherwise, throw an exception indicating that the data in the
    * request was not valid.
    */
   void convertSources(Request request, SourceFactory sourceFactory, RequestDatum sources, void handler(Source source)) {
@@ skipping 82 matching lines @@
    */
   AnalysisContext getAnalysisContext(Request request) {
     String contextId = request.getRequiredParameter(CONTEXT_ID_PARAM).asString();
     AnalysisContext context = server.contextMap[contextId];
     if (context == null) {
       throw new RequestFailure(new Response.contextDoesNotExist(request));
     }
     return context;
   }
 }