Re: [RFA 08/11] Use string and unique_xmalloc_ptr in mi-main.c

Pedro Alves
2017-09-28T09:57:14Z

On 09/12/2017 07:57 PM, Tom Tromey wrote:
> Change a couple of spots in mi-main.c to use std::string or
> unique_xmalloc_ptr. unique_xmalloc_ptr is used here where the string
> is writeable; I generally prefer to pretend that string is read-only,
> perhaps not for a good resaon.

Yes, I think not for a good reason. :-) You can
pass &str[0] to execute_command get access to the underlying
modifiable raw string. See b064640146bb for example.

> diff --git a/gdb/mi/mi-main.c b/gdb/mi/mi-main.c
> index c8c4a97..0147fb9 100644
> --- a/gdb/mi/mi-main.c
> +++ b/gdb/mi/mi-main.c
> @@ -2264,41 +2264,31 @@ mi_execute_cli_command (const char *cmd, int args_p, const char *args)
> {
> if (cmd != 0)
> {
> - struct cleanup *old_cleanups;
> - char *run;
> + gdb::unique_xmalloc_ptr<char> run;
>
> if (args_p)
> - run = xstrprintf ("%s %s", cmd, args);
> + run.reset (xstrprintf ("%s %s", cmd, args));
> else
> - run = xstrdup (cmd);
> + run.reset (xstrdup (cmd));
> if (mi_debug_p)
> /* FIXME: gdb_???? */
> fprintf_unfiltered (gdb_stdout, "cli=%s run=%s\n",
> - cmd, run);
> - old_cleanups = make_cleanup (xfree, run);
> - execute_command (run, 0 /* from_tty */ );
> - do_cleanups (old_cleanups);
> - return;
> + cmd, run.get ());
> + execute_command (run.get (), 0 /* from_tty */ );
> }
> }
>
> void
> mi_execute_async_cli_command (const char *cli_command, char **argv, int argc)
> {
> - struct cleanup *old_cleanups;
> - char *run;
> + gdb::unique_xmalloc_ptr<char> run;
>
> if (mi_async_p ())
> - run = xstrprintf ("%s %s&", cli_command, argc ? *argv : "");
> + run.reset (xstrprintf ("%s %s&", cli_command, argc ? *argv : ""));
> else
> - run = xstrprintf ("%s %s", cli_command, argc ? *argv : "");
> - old_cleanups = make_cleanup (xfree, run);
> -
> - execute_command (run, 0 /* from_tty */ );
> + run.reset (xstrprintf ("%s %s", cli_command, argc ? *argv : ""));
>
> - /* Do this before doing any printing. It would appear that some
> - print code leaves garbage around in the buffer. */
> - do_cleanups (old_cleanups);
> + execute_command (run.get (), 0 /* from_tty */ );
> }
>

I think the above would look better with std::string + string_printf.

> struct trace_state_variable *tsv;
> @@ -2822,10 +2808,8 @@ mi_cmd_trace_frame_collected (const char *command, char **argv, int argc)
>
> if (tsv != NULL)
> {
> - tsvname = (char *) xrealloc (tsvname, strlen (tsv->name) + 2);
> - tsvname[0] = '$';
> - strcpy (tsvname + 1, tsv->name);
> - uiout->field_string ("name", tsvname);
> + std::string tsvname = std::string ("$") + tsv->name;
> + uiout->field_string ("name", tsvname.c_str ());

How about replacing this string building + field_string with a single
call to:

uiout->field_fmt ("name", "$%s", tsv->name);

Thanks,
Pedro Alves