Don't send PP_Vars/V8 values with cycles across PostMessage

webkit/plugins/ppapi/v8_var_converter.h

 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef WEBKIT_PLUGINS_PPAPI_V8_VAR_CONVERTER_H
 #define WEBKIT_PLUGINS_PPAPI_V8_VAR_CONVERTER_H
 
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "ppapi/c/pp_var.h"
 #include "v8/include/v8.h"
 #include "webkit/plugins/webkit_plugins_export.h"
 
 namespace webkit {
 namespace ppapi {
 
 // Class to convert between PP_Vars and V8 values.
 class WEBKIT_PLUGINS_EXPORT V8VarConverter {
  public:
-  V8VarConverter();
+  V8VarConverter(bool allow_cycles);

[dmichael (off chromium), 2013/06/04 16:59:10]

Better to just always disallow them, I think. We can dig the cycle passing stuff
out of source control; no need to maintain a dead branch of code.

[raymes, 2013/06/04 19:36:06]

Done.

 
   // Converts the given PP_Var to a v8::Value. True is returned upon success.
   bool ToV8Value(const PP_Var& var,
                  v8::Handle<v8::Context> context,
                  v8::Handle<v8::Value>* result) const;

[dmichael (off chromium), 2013/06/04 16:59:10]

side issue: Looking at this now, these should probably be static, and the
default constructor could be private & unimplemented (or omitted; I think
declaring a copy ctor in DISALLOW_COPY_AND_ASSIGN might be enough for the
compiler to not generate a default constructor). 

(V8VarConverter could even be a namespace instead of a utility class).

[raymes, 2013/06/04 19:36:06]

Done.

   // Converts the given v8::Value to a PP_Var. True is returned upon success.
   // Every PP_Var in the reference graph of which |result| is apart will have
   // a refcount equal to the number of references to it in the graph. |result|
   // will have one additional reference.
   bool FromV8Value(v8::Handle<v8::Value> val,
                    v8::Handle<v8::Context> context,
                    PP_Var* result) const;
 
+ private:
+  bool allow_cycles_;
+
   DISALLOW_COPY_AND_ASSIGN(V8VarConverter);
 };
 
 }  // namespace ppapi
 }  // namespace webkit
 
 #endif  // WEBKIT_PLUGINS_PPAPI_V8_VAR_CONVERTER_H