How to parse JSON in an embedded v8?

Question

I am trying to Parse JS in my embedded V8 application and I get a SIGSEGV always. I am not sure what is happening.

My code to parse json,

v8::Handle<v8::Value> FromJSONString(
    v8::Handle<v8::Value> json_string) {
  v8::HandleScope scope;
  v8::Handle<v8::Context> context = v8::Context::GetCurrent();
  v8::Handle<v8::Object> global = context->Global();

  v8::Handle<v8::Value> JSON_value = global->Get(v8::String::New("JSON"));
  if (!IsObject(JSON_value)) {
    return scope.Close(v8::Undefined());
  }
  v8::Handle<v8::Object> JSON  = JSON_value->ToObject();

  v8::Handle<v8::Value> JSON_parse_value = JSON->Get(v8::String::New("parse"));

  if (JSON_parse_value.IsEmpty() || JSON_parse_value->IsNull() ||
      JSON_parse_value->IsUndefined() ||!JSON_parse_value->IsFunction()) {
    return scope.Close(v8::Undefined());
  }


  v8::Handle<v8::Function> JSON_parse =
      v8::Handle<v8::Function>::Cast(JSON_parse_value);

  return scope.Close(JSON_parse->Call(JSON, 1, &json_string));
}

The specific site which crashes =>

bool extractSource(std::string* source, std::string& body) {
    v8::HandleScope scope; // this is needed and clears the memory
    if (body.empty()) {
        return false;
    }
    v8::Handle<v8::Value> value = v8_server_utils::FromJSONString(body);
    if (value->IsEmpty()) { // CRASHES HERE.
        return false;
    }
    if (value->IsNull()) {
        return false;
    }
    if (value->IsUndefined()) {
        return false;
    }
    if (!value->IsObject()) {
        return false;
    }
    auto object = value->ToObject();
    auto source_key = v8::String::New("source");
    if (object.IsEmpty() || object->IsNull() || object->IsUndefined() ||
        !object->Has(source_key)) {
        return false;
    }
    auto source_obj = object->Get(source_key);
    *source = v8_server_utils::JSStringToCString(source_obj->ToString());
    return true;
}

Answer 1

You can use JSON Parse function exposed through API:

v8::Local<v8::String> str; // some string
v8::Local<v8::Value> result = v8::JSON::Parse(str);

Newer versions of V8 provide EscapableHandleScope you need to use to return handle from function:

v8::EscapableHandleScope scope(isolate);
return scope.Escape(value);

This

if (value->IsEmpty()) { // CRASHES HERE.

should probably be

if (value.IsEmpty())

Hope this helps.