Re: [PATCH] Consolidate the custom TUI query hook with default query hook

[Pedro Alves <palves at redhat dot com>]

On 01/08/2015 03:17 PM, Patrick Palka wrote:
> Hi Pedro,
> 
> This is what I have so far.  It seems to work well.  Thoughts?

Nice!

> --- a/gdb/utils.c
> +++ b/gdb/utils.c
> @@ -1198,12 +1198,11 @@ compile_rx_or_error (regex_t *pattern, const char *rx, const char *message)
>  static int ATTRIBUTE_PRINTF (1, 0)
>  defaulted_query (const char *ctlstr, const char defchar, va_list args)
>  {
> -  int answer;
>    int ans2;
>    int retval;
>    int def_value;
>    char def_answer, not_def_answer;
> -  char *y_string, *n_string, *question;
> +  char *y_string, *n_string, *question, *prompt;
>    /* Used to add duration we waited for user to respond to
>       prompt_for_continue_wait_time.  */
>    struct timeval prompt_started, prompt_ended, prompt_delta;
> @@ -1263,62 +1262,31 @@ defaulted_query (const char *ctlstr, const char defchar, va_list args)
>  
>    /* Format the question outside of the loop, to avoid reusing args.  */
>    question = xstrvprintf (ctlstr, args);
> +  prompt = xstrprintf ("%s%s(%s or %s) %s",

Add _() here, for the "or".

> -      printf_filtered (_("(%s or %s) "), y_string, n_string);

Notice here we had it.

> -
> -      if (annotation_level > 1)
> -	printf_filtered (("\n\032\032query\n"));
> +      char *response, answer = EOF;
>  
> -      wrap_here ("");
>        gdb_flush (gdb_stdout);
> +      response = gdb_readline_wrapper (prompt);
> +      if (response != NULL)
> +	answer = response[0];
> +      xfree (response);
>  
> -      answer = fgetc (stdin);
> -
> -      /* We expect fgetc to block until a character is read.  But
> -         this may not be the case if the terminal was opened with
> -         the NONBLOCK flag.  In that case, if there is nothing to
> -         read on stdin, fgetc returns EOF, but also sets the error
> -         condition flag on stdin and errno to EAGAIN.  With a true
> -         EOF, stdin's error condition flag is not set.
> -
> -         A situation where this behavior was observed is a pseudo
> -         terminal on AIX.  */
> -      while (answer == EOF && ferror (stdin) && errno == EAGAIN)
> -        {
> -          /* Not a real EOF.  Wait a little while and try again until
> -             we read something.  */
> -          clearerr (stdin);
> -          gdb_usleep (10000);
> -          answer = fgetc (stdin);
> -        }
> -
> -      clearerr (stdin);		/* in case of C-d */
>        if (answer == EOF)	/* C-d */
>  	{
>  	  printf_filtered ("EOF [assumed %c]\n", def_answer);
>  	  retval = def_value;
>  	  break;
>  	}

Can you move this a bit above, and write the check in
terms of response, like this?

        if (response == NULL)	/* C-d */
  	{
  	  printf_filtered ("EOF [assumed %c]\n", def_answer);
  	  retval = def_value;
  	  break;
  	}

I think that's a little bit clearer.  What got me to that was that
you made "answer" a char (from int), which may be signed or unsigned,
depending on host, and then the >= 'a' check further below looked
suspicious, though I see that it's unreachable for the EOF case.  I think
that way there'll no be reference to EOF at all in the
code (except in the printf string).

Other than that, if this passes testing, that it's OK with me.

Thanks for doing this.

-- 
Pedro Alves