Re: [RFA 09/22] Remove make_cleanup_restore_current_ui

[Simon Marchi <simon dot marchi at polymtl dot ca>]

On 2016-09-27 00:08, Tom Tromey wrote:
> --- a/gdb/top.h
> +++ b/gdb/top.h
> @@ -155,27 +155,52 @@ extern struct ui *current_ui;
>  /* The list of all UIs.  */
>  extern struct ui *ui_list;
>
> -/* State for SWITCH_THRU_ALL_UIS.  Declared here because it is meant
> -   to be created on the stack, but should be treated as opaque.  */
> -struct switch_thru_all_uis
> +/* State for SWITCH_THRU_ALL_UIS.  */
> +class switch_thru_all_uis
>  {
> +public:
> +
> +  switch_thru_all_uis () : iter (nullptr), save_ui (&current_ui)

We are targetting C++98, aren't we?  Or is it C++03?  Either way, 
nullptr appeared in C++11, so I guess we can't use it.

The fact that your compiler (and mine) did not catch this begs the 
question, should we have one of -std=c++98/gnu++98/c++03/gnu++03 in our 
compilation flags, instead of relying of the compiler's default mode?

> +  {
> +    iter = ui_list;
> +  }
> +
> +  ~switch_thru_all_uis ()
> +  {
> +  }
> +
> +  // If done iterating, return true; otherwise return false.
> +  bool done () const
> +  {
> +    return iter == nullptr;
> +  }
> +
> +  // Move to the next UI, setting current_ui if iteration is not yet
> +  // complete.
> +  void next ()
> +  {
> +    iter = iter->next;
> +    if (iter != nullptr)
> +      current_ui = iter;
> +  }
> +
> + private:
> +
> +  // No need for these.  They are intentionally not defined anywhere.
> +  switch_thru_all_uis &operator= (const switch_thru_all_uis &);
> +  switch_thru_all_uis (const switch_thru_all_uis &);
> +
> +  // Used to iterate through the UIs.
>    struct ui *iter;
> -  struct cleanup *old_chain;
> -};
>
> -/* Functions to drive SWITCH_THRU_ALL_UIS.  Though declared here by
> -   necessity, these functions should not be used other than via the
> -   SWITCH_THRU_ALL_UIS macro defined below.  */
> -extern void switch_thru_all_uis_init (struct switch_thru_all_uis 
> *state);
> -extern int switch_thru_all_uis_cond (struct switch_thru_all_uis 
> *state);
> -extern void switch_thru_all_uis_next (struct switch_thru_all_uis 
> *state);
> +  // Save and restore current_ui.
> +  scoped_restore<struct ui *> save_ui;
> +};
>
>    /* Traverse through all UI, and switch the current UI to the one
>       being iterated.  */
>  #define SWITCH_THRU_ALL_UIS(STATE)		\

You can remove STATE here.  I am surprised the preprocessor doesn't care 
about the missing argument in macro references.