Issue 2399 part 1: In debugger allow modifying local variable values

src/mirror-debugger.js

 // Copyright 2006-2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1826 matching lines @@
 var kScopeDetailsTypeIndex = 0;
 var kScopeDetailsObjectIndex = 1;
 
 function ScopeDetails(frame, fun, index) {
   if (frame) {
     this.break_id_ = frame.break_id_;
     this.details_ = %GetScopeDetails(frame.break_id_,
                                      frame.details_.frameId(),
                                      frame.details_.inlinedFrameIndex(),
                                      index);
+    this.frame_id_ = frame.details_.frameId();
+    this.inlined_frame_id_ = frame.details_.inlinedFrameIndex();
   } else {
     this.details_ = %GetFunctionScopeDetails(fun.value(), index);
+    this.fun_value_ = fun.value();
     this.break_id_ = undefined;
   }
+  this.index_ = index;
 }
 
 
 ScopeDetails.prototype.type = function() {
   if (!IS_UNDEFINED(this.break_id_)) {
     %CheckExecutionState(this.break_id_);
   }
   return this.details_[kScopeDetailsTypeIndex];
 };
 
 
 ScopeDetails.prototype.object = function() {
   if (!IS_UNDEFINED(this.break_id_)) {
     %CheckExecutionState(this.break_id_);
   }
   return this.details_[kScopeDetailsObjectIndex];
 };
 
 
+ScopeDetails.prototype.setVariableValueImpl = function(name, new_value) {
+  var raw_res;
+  if (!IS_UNDEFINED(this.break_id_)) {
+    %CheckExecutionState(this.break_id_);
+    raw_res = %SetScopeVariableValue(this.break_id_, this.frame_id_,
+        this.inlined_frame_id_, this.index_, name, new_value);
+  } else {
+    raw_res = %SetScopeVariableValue(this.fun_value_, null, null, this.index_,
+        name, new_value);
+  }
+  if (!raw_res) {
+    throw new Error("Failed to set variable value");
+  }
+};
+
+
 /**
  * Mirror object for scope of frame or function. Either frame or function must
  * be specified.
  * @param {FrameMirror} frame The frame this scope is a part of
  * @param {FunctionMirror} function The function this scope is a part of
  * @param {number} index The scope index in the frame
  * @constructor
  * @extends Mirror
  */
 function ScopeMirror(frame, function, index) {
@@ skipping 27 matching lines @@
 ScopeMirror.prototype.scopeObject = function() {
   // For local and closure scopes create a transient mirror as these objects are
   // created on the fly materializing the local or closure scopes and
   // therefore will not preserve identity.
   var transient = this.scopeType() == ScopeType.Local ||
                   this.scopeType() == ScopeType.Closure;
   return MakeMirror(this.details_.object(), transient);
 };
 
 
+ScopeMirror.prototype.setVariableValue = function(name, new_value) {
+  this.details_.setVariableValueImpl(name, new_value);
+};
+
+
 /**
  * Mirror object for script source.
  * @param {Script} script The script object
  * @constructor
  * @extends Mirror
  */
 function ScriptMirror(script) {
   %_CallFunction(this, SCRIPT_TYPE, Mirror);
   this.script_ = script;
   this.context_ = new ContextMirror(script.context_data);
@@ skipping 665 matching lines @@
   }
   if (!NUMBER_IS_FINITE(value)) {
     if (value > 0) {
       return 'Infinity';
     } else {
       return '-Infinity';
     }
   }
   return value;
 }