Re: [PATCH] Use thread_info and inferior pointers more throughout

[Tom Tromey <tom at tromey dot com>]

>>>>> "Pedro" == Pedro Alves <palves@redhat.com> writes:

Pedro> In many cases though, we already have the thread_info or inferior
Pedro> pointer handy, but we "lose" it somewhere along the call stack, only
Pedro> to look it up again by ptid_t/pid.  Since thread_info or inferior
Pedro> objects know their parent target, if we pass around thread_info or
Pedro> inferior pointers when possible, we avoid having to add extra
Pedro> target_ops parameters to many functions, and also, we eliminate a
Pedro> number of by ptid_t/int lookups.

This seems like a good idea.  I've sometimes wondered why ptid was used
rather than object pointers; but now it seems that there was no deep
reason :)

Pedro> - Related, there's a spot where using a RAII object to handle the
Pedro>   refcount would be handy, so a new scoped_inc_dec_ref class is added
Pedro>   to common/refcounted-object.h.

It seems to me that this could be done via gdb::ref_ptr plus a simple
policy class that interfaces it to refcounted_object.

Pedro> +/* A RAII type that increments/decrements the refcount of an object on
Pedro> +   enter/exit of a scope.  */
Pedro> +
Pedro> +class scoped_inc_dec_ref
Pedro> +{
Pedro> +public:
Pedro> +  explicit scoped_inc_dec_ref (refcounted_object *obj)
Pedro> +    : m_obj (obj)
Pedro> +  {
Pedro> +    m_obj->incref ();
Pedro> +  }
Pedro> +
Pedro> +  ~scoped_inc_dec_ref ()
Pedro> +  {
Pedro> +    m_obj->decref ();
Pedro> +  }

... if you do keep this it probably needs DISABLE_COPY_AND_ASSIGN.

Tom