From: Daniel Harple <dharple@...>
Date: 2006-08-09T06:58:28+09:00
Subject: Re: Using C++ Member Function with rb_protect

On Aug 8, 2006, at 5:34 PM, Mauricio Fernandez wrote:

> Of course it won't work that way, being a member function (it is  
> given a
> reference to this too...).
>
> You'd have to do something like this (it's been a while without  
> writing any
> C++, so take this with a grain of salt):

Thanks, I ended up with something similar.

class Sandbox
{
public:
     Sandbox() {
         sandbox_ = rb_funcall(rb_const_get(rb_cObject, rb_intern 
("Sandbox")),
                               rb_intern("safe"),
                               0);
     }
     virtual ~Sandbox() { }
     VALUE eval(char * code) {
         int status = 0;
         VALUE args[2];
         args[0] = reinterpret_cast<VALUE>(this);
         args[1] = rb_str_new2(code);
         VALUE val = rb_protect(eval_protect,
                                reinterpret_cast<VALUE>(args),
                                &status);
         if (status) { }
         return val;
     }

     VALUE & sandbox() {
         return sandbox_;
     }
private:
     VALUE sandbox_;
     static VALUE eval_protect(VALUE data) {
         VALUE *args = reinterpret_cast<VALUE *>(data);
         return rb_funcall(reinterpret_cast<Sandbox *>(args[0])- 
 >sandbox(),
                           rb_intern("eval"),
                           1,
                           args[1]);
     }
};

-- Daniel