Check for reset during 'await' in refactoring manager.

pkg/analysis_server/lib/src/edit/edit_domain.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 edit.domain;
 
 import 'dart:async';
 
 import 'package:analysis_server/edit/assist/assist_core.dart';
 import 'package:analysis_server/edit/fix/fix_core.dart';
@@ skipping 14 matching lines @@
 import 'package:analyzer/src/generated/error.dart' as engine;
 import 'package:analyzer/src/generated/parser.dart' as engine;
 import 'package:analyzer/src/generated/scanner.dart' as engine;
 import 'package:analyzer/src/generated/source.dart';
 import 'package:dart_style/dart_style.dart';
 
 bool test_simulateRefactoringException_change = false;
 bool test_simulateRefactoringException_final = false;
 bool test_simulateRefactoringException_init = false;
 
+bool test_simulateRefactoringReset_afterCreateChange = false;
+bool test_simulateRefactoringReset_afterFinalConditions = false;
+bool test_simulateRefactoringReset_afterInitialConditions = false;
+
 /**
  * Instances of the class [EditDomainHandler] implement a [RequestHandler]
  * that handles requests in the edit domain.
  */
 class EditDomainHandler implements RequestHandler {
   /**
    * The analysis server that is using this handler to process requests.
    */
   final AnalysisServer server;
 
@@ skipping 400 matching lines @@
         finalStatus = new RefactoringStatus();
         _sendResultResponse();
         return;
       }
       // simulate an exception
       if (test_simulateRefactoringException_final) {
         throw 'A simulated refactoring exception - final.';
       }
       // validation and create change
       finalStatus = await refactoring.checkFinalConditions();
+      _checkForReset_afterFinalConditions();
       if (_hasFatalError) {
         _sendResultResponse();
         return;
       }
       // simulate an exception
       if (test_simulateRefactoringException_change) {
         throw 'A simulated refactoring exception - change.';
       }
       // create change
       result.change = await refactoring.createChange();
       result.potentialEdits = nullIfEmpty(refactoring.potentialEditIds);
+      _checkForReset_afterCreateChange();
       _sendResultResponse();
     }, onError: (exception, stackTrace) {
-      server.instrumentationService.logException(exception, stackTrace);
-      server.sendResponse(
-          new Response.serverError(_request, exception, stackTrace));
+      if (exception is _ResetError) {
+        cancel();
+      } else {
+        server.instrumentationService.logException(exception, stackTrace);
+        server.sendResponse(
+            new Response.serverError(_request, exception, stackTrace));
+      }
       _reset();
     });
   }
 
+  void _checkForReset_afterCreateChange() {
+    if (test_simulateRefactoringReset_afterCreateChange) {
+      _reset();
+    }
+    if (refactoring == null) {
+      throw new _ResetError();
+    }
+  }
+
+  void _checkForReset_afterFinalConditions() {
+    if (test_simulateRefactoringReset_afterFinalConditions) {
+      _reset();
+    }
+    if (refactoring == null) {
+      throw new _ResetError();
+    }
+  }
+
+  void _checkForReset_afterInitialConditions() {
+    if (test_simulateRefactoringReset_afterInitialConditions) {
+      _reset();
+    }
+    if (refactoring == null) {
+      throw new _ResetError();
+    }
+  }
+
   /**
    * Initializes this context to perform a refactoring with the specified
    * parameters. The existing [Refactoring] is reused or created as needed.
    */
   Future _init(
       RefactoringKind kind, String file, int offset, int length) async {
     await server.onAnalysisComplete;
     // check if we can continue with the existing Refactoring instance
     if (this.kind == kind &&
         this.file == file &&
@@ skipping 89 matching lines @@
             new RenameFeedback(node.offset, node.length, 'kind', 'oldName');
       }
     }
     if (refactoring == null) {
       initStatus =
           new RefactoringStatus.fatal('Unable to create a refactoring');
       return;
     }
     // check initial conditions
     initStatus = await refactoring.checkInitialConditions();
+    _checkForReset_afterInitialConditions();
     if (refactoring is ExtractLocalRefactoring) {
       ExtractLocalRefactoring refactoring = this.refactoring;
       ExtractLocalVariableFeedback feedback = this.feedback;
       feedback.names = refactoring.names;
       feedback.offsets = refactoring.offsets;
       feedback.lengths = refactoring.lengths;
     }
     if (refactoring is ExtractMethodRefactoring) {
       ExtractMethodRefactoring refactoring = this.refactoring;
       ExtractMethodFeedback feedback = this.feedback;
@@ skipping 91 matching lines @@
     }
     if (refactoring is RenameRefactoring) {
       RenameRefactoring renameRefactoring = refactoring;
       RenameOptions renameOptions = params.options;
       renameRefactoring.newName = renameOptions.newName;
       return renameRefactoring.checkNewName();
     }
     return new RefactoringStatus();
   }
 }
+
+/**
+ * [_RefactoringManager] throws instances of this class internally to stop
+ * processing in a manager that was reset.
+ */
+class _ResetError {}