[08/14] Remove the TUI register window rerender overload

  After these restructurings, it should be clear that the rerender
overload can be removed from the TUI register window.  This is done by
moving a bit more logic from show_registers into update_register_data.
After this, update_register_data simply updates the internal state,
and rerender will write to the screen.  All the actual rendering work
is done, ultimately, by display_registers_from.  This split between
updating the mode and rendering makes it clear that the recursive case
can't happen any longer.
---
 gdb/tui/tui-regs.c | 55 ++++++++++++++++++++++++------------------------------
 gdb/tui/tui-regs.h | 14 ++++++--------
 2 files changed, 30 insertions(+), 39 deletions(-)
  

Tom Tromey <tom@tromey.com> writes:

> After these restructurings, it should be clear that the rerender
> overload can be removed from the TUI register window.  This is done by
> moving a bit more logic from show_registers into update_register_data.
> After this, update_register_data simply updates the internal state,
> and rerender will write to the screen.  All the actual rendering work
> is done, ultimately, by display_registers_from.  This split between
> updating the mode and rendering makes it clear that the recursive case
> can't happen any longer.
> ---
>  gdb/tui/tui-regs.c | 55 ++++++++++++++++++++++++------------------------------
>  gdb/tui/tui-regs.h | 14 ++++++--------
>  2 files changed, 30 insertions(+), 39 deletions(-)
>
> diff --git a/gdb/tui/tui-regs.c b/gdb/tui/tui-regs.c
> index 7b6b669fe51..5726dc3fea8 100644
> --- a/gdb/tui/tui-regs.c
> +++ b/gdb/tui/tui-regs.c
> @@ -165,31 +165,33 @@ tui_data_window::first_reg_element_no_inline (int line_no) const
>     and refresh the window.  */
>  void
>  tui_data_window::show_registers (const reggroup *group)
> +{
> +  update_register_data (group);
> +  rerender ();
> +}
> +
> +/* Set the data window to display the registers of the register group
> +   using the given frame.  Values are refreshed only when
> +   refresh_values_only is true.  */
> +
> +void
> +tui_data_window::update_register_data (const reggroup *group)

Function comment is not correct.

>  {
>    if (group == nullptr)
>      group = general_reggroup;
>  
> -  if (target_has_registers () && target_has_stack () && target_has_memory ())
> -    update_register_data (group, get_selected_frame (nullptr));
> -  else
> +  if (!target_has_registers ()
> +      || !target_has_stack ()
> +      || !target_has_memory ())
>      {
> -      set_title (_("Registers"));
> +      set_title ("");

This is the title change I pointed out in the previous commit.  I
actually like the 'Registers' string as it means the window always has a
title, rather than the title appearing  / disappearing.

Thanks,
Andrew
>        m_current_group = nullptr;
>        m_regs_content.clear ();
> +      return;
>      }
>  
> -  rerender (false);
> -}
> -
> -
> -/* Set the data window to display the registers of the register group
> -   using the given frame.  Values are refreshed only when
> -   refresh_values_only is true.  */
> +  frame_info_ptr frame = get_selected_frame (nullptr);
>  
> -void
> -tui_data_window::update_register_data (const reggroup *group,
> -				       frame_info_ptr frame)
> -{
>    m_current_group = group;
>  
>    /* Make a new title showing which group we display.  */
> @@ -222,6 +224,9 @@ tui_data_window::update_register_data (const reggroup *group,
>  void
>  tui_data_window::display_registers_from (int start_element_no)
>  {
> +  werase (handle.get ());
> +  check_and_display_highlight_if_needed ();
> +
>    /* In case the regs window is not boxed, we'll write the last char in the
>       last line here, causing a scroll, so prevent that.  */
>    scrollok (handle.get (), FALSE);
> @@ -358,29 +363,18 @@ tui_data_window::erase_data_content (const char *prompt)
>  	x_pos = half_width - strlen (prompt);
>        display_string (height / 2, x_pos, prompt);
>      }
> -  tui_wrefresh (handle.get ());
>  }
>  
>  /* See tui-regs.h.  */
>  
>  void
> -tui_data_window::rerender (bool toplevel)
> +tui_data_window::rerender ()
>  {
>    if (m_regs_content.empty ())
> -    {
> -      if (toplevel && has_stack_frames ())
> -	{
> -	  frame_info_ptr fi = get_selected_frame (NULL);
> -	  check_register_values (fi);
> -	}
> -      else
> -	erase_data_content (_("[ Register Values Unavailable ]"));
> -    }
> +    erase_data_content (_("[ Register Values Unavailable ]"));
>    else
> -    {
> -      erase_data_content (NULL);
> -      display_registers_from (0);
> -    }
> +    display_registers_from (0);
> +  tui_wrefresh (handle.get ());
>  }
>  
>  
> @@ -402,7 +396,6 @@ tui_data_window::do_scroll_vertical (int num_to_scroll)
>    if (first_line >= 0)
>      {
>        first_line += num_to_scroll;
> -      erase_data_content (NULL);
>        display_registers_from_line (first_line);
>      }
>  }
> diff --git a/gdb/tui/tui-regs.h b/gdb/tui/tui-regs.h
> index 701b8707947..b31a5a3e5b8 100644
> --- a/gdb/tui/tui-regs.h
> +++ b/gdb/tui/tui-regs.h
> @@ -56,7 +56,10 @@ struct tui_register_info
>  /* The TUI registers window.  */
>  struct tui_data_window : public tui_win_info
>  {
> -  tui_data_window () = default;
> +  tui_data_window ()
> +  {
> +    update_register_data (nullptr);
> +  }
>  
>    DISABLE_COPY_AND_ASSIGN (tui_data_window);
>  
> @@ -81,11 +84,7 @@ struct tui_data_window : public tui_win_info
>    {
>    }
>  
> -  void rerender (bool toplevel);
> -  void rerender () override
> -  {
> -    rerender (true);
> -  }
> +  void rerender () override;
>  
>  private:
>  
> @@ -110,8 +109,7 @@ struct tui_data_window : public tui_win_info
>       display off the end of the register display.  */
>    void display_reg_element_at_line (int start_element_no, int start_line_no);
>  
> -  void update_register_data (const reggroup *group,
> -			     frame_info_ptr frame);
> +  void update_register_data (const reggroup *group);
>  
>    /* Answer the number of the last line in the regs display.  If there
>       are no registers (-1) is returned.  */
>
> -- 
> 2.43.0
  

>> -      set_title (_("Registers"));
>> +      set_title ("");

Andrew> This is the title change I pointed out in the previous commit.  I
Andrew> actually like the 'Registers' string as it means the window always has a
Andrew> title, rather than the title appearing  / disappearing.

I went ahead & left it in.

Tom