Implement rewind: drop one or more frames from the debugger.

runtime/observatory/lib/src/service/object.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.
 
 part of service;
 
 // Some value smaller than the object ring, so requesting a large array
 // doesn't result in an expired ref because the elements lapped it in the
 // object ring.
 const int kDefaultFieldLimit = 100;
@@ skipping 24 matching lines @@
   static const kInvalidRequest = -32600;
   static const kMethodNotFound = -32601;
   static const kInvalidParams = -32602;
   static const kInternalError = -32603;
   static const kFeatureDisabled = 100;
   static const kCannotAddBreakpoint = 102;
   static const kStreamAlreadySubscribed = 103;
   static const kStreamNotSubscribed = 104;
   static const kIsolateMustBeRunnable = 105;
   static const kIsolateMustBePaused = 106;
+  static const kCannotResume = 107;
   static const kIsolateIsReloading = 1000;
   static const kFileSystemAlreadyExists = 1001;
   static const kFileSystemDoesNotExist = 1002;
   static const kFileDoesNotExist = 1003;
   static const kIsolateReloadFailed = 1004;
+  static const kIsolateReloadBarred = 1005;
 
   int code;
   Map data;
 
   static _getMessage(Map errorMap) {
     Map data = errorMap['data'];
     if (data != null && data['details'] != null) {
       return data['details'];
     } else {
       return errorMap['message'];
@@ skipping 1212 matching lines @@
     idle = (!paused && topFrame == null);
   }
 
   M.DebugEvent pauseEvent = null;
   bool paused = false;
   bool running = false;
   bool idle = false;
   bool loading = true;
   bool runnable = false;
   bool ioEnabled = false;
-  bool reloading = false;
   M.IsolateStatus get status {
     if (paused) {
       return M.IsolateStatus.paused;
     }
     if (running) {
       return M.IsolateStatus.running;
     }
     if (idle) {
       return M.IsolateStatus.idle;
     }
@@ skipping 44 matching lines @@
       {String rootLibUri,
        bool pause}) {
     Map<String, dynamic> params = <String, dynamic>{};
     if (rootLibUri != null) {
       params['rootLibUri'] = rootLibUri;
     }
     if (pause != null) {
       params['pause'] = pause;
     }
     return invokeRpc('reloadSources', params).then((result) {
-      reloading = true;
+      _cache.clear();
       return result;
     });
   }
 
   void _handleIsolateReloadEvent(ServiceEvent event) {
-    reloading = false;
     if (event.reloadError != null) {
       // Failure.
       print('Reload failed: ${event.reloadError}');
     } else {
       _cache.clear();
     }
   }
 
   /// Fetches and builds the class hierarchy for this isolate. Returns the
   /// Object class object.
@@ skipping 397 matching lines @@
   }
 
   Future stepOverAsyncSuspension() {
     return invokeRpc('resume', {'step': 'OverAsyncSuspension'});
   }
 
   Future stepOut() {
     return invokeRpc('resume', {'step': 'Out'});
   }
 
+  Future rewind(int count) {
+    return invokeRpc('resume', {'step': 'Rewind', 'frameIndex': count});
+  }
+
   Future setName(String newName) {
     return invokeRpc('setName', {'name': newName});
   }
 
   Future setExceptionPauseMode(String mode) {
     return invokeRpc('setExceptionPauseMode', {'mode': mode});
   }
 
   Future<ServiceMap> getStack() {
     return invokeRpc('getStack', {});
@@ skipping 2626 matching lines @@
     var v = list[i];
     if ((v is Map) && _isServiceMap(v)) {
       list[i] = owner.getFromMap(v);
     } else if (v is List) {
       _upgradeList(v, owner);
     } else if (v is Map) {
       _upgradeMap(v, owner);
     }
   }
 }