Re: GDB/MI and ">" prompts

Eli Zaretskii
2012-04-28T08:33:38Z

Ping! Is the patch below OK for committing?

> Date: Sun, 22 Apr 2012 19:04:17 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: gdb-patches@sourceware.org
>
> [I moved this to gdb-patches, since I propose a patch below.]
>
> > Date: Thu, 19 Apr 2012 22:24:53 +0300
> > From: Eli Zaretskii <eliz@gnu.org>
> > Cc: gdb@sourceware.org
> >
> > The crux of my question was why non-interactive mode does display a
> > prompt while the interactive one doesn't.
>
> To answer my own question, here's why:
>
> char *
> command_line_input (char *prompt_arg, int repeat, char *annotation_suffix)
> {
> ...
> /* Don't use fancy stuff if not talking to stdin. */
> if (deprecated_readline_hook && input_from_terminal_p ())
> {
> rl = (*deprecated_readline_hook) (local_prompt);
> }
> else if (command_editing_p && input_from_terminal_p ())
> {
> rl = gdb_readline_wrapper (local_prompt);
> }
> else
> {
> rl = gdb_readline (local_prompt);
> }
>
> Now, the code is clear, but I cannot say I understand the logic. If
> the input is from terminal, we ask (inside gdb_readline_wrapper) the
> current interpreter whether to show the prompt. But if input is _not_
> from terminal, we display the prompt unconditionally (inside
> gdb_readline). How does this make sense?
>
> > Date: Thu, 19 Apr 2012 11:53:29 -0700
> > From: Joel Brobecker <brobecker@adacore.com>
> > Cc: gdb@sourceware.org
> >
> > The other thing that occured to me was that, perhaps, we should instead
> > be switching the interpreter while executing the console command,
>
> I arrived to the same conclusion, eventually. See below.
>
> > but I doubt that would be correct.
>
> Why not? The patch below works for me.
>
> --- gdb/interps.c~0 2012-01-06 06:43:17.000000000 +0200
> +++ gdb/interps.c 2012-04-22 08:55:27.056588400 +0300
> @@ -253,6 +253,18 @@ interp_ui_out (struct interp *interp)
> return current_interpreter->procs->ui_out_proc (current_interpreter);
> }
>
> +/* Temporarily overrides the current interpreter. */
> +struct interp *
> +interp_set_temp (const char *name)
> +{
> + struct interp *interp = interp_lookup (name);
> + struct interp *old_interp = current_interpreter;
> +
> + if (interp)
> + current_interpreter = interp;
> + return old_interp;
> +}
> +
> /* Returns the interpreter's cookie. */
>
> void *
> --- gdb/interps.h~0 2012-01-06 06:43:17.000000000 +0200
> +++ gdb/interps.h 2012-04-22 08:42:05.687879800 +0300
> @@ -69,6 +69,7 @@
> extern struct ui_out *interp_ui_out (struct interp *interp);
> extern void *interp_data (struct interp *interp);
> extern const char *interp_name (struct interp *interp);
> +extern struct interp *interp_set_temp (const char *name);
>
> extern int current_interp_named_p (const char *name);
> extern int current_interp_display_prompt_p (void);
> --- gdb/cli/cli-script.c~0 2012-01-06 06:43:32.000000000 +0200
> +++ gdb/cli/cli-script.c 2012-04-22 09:04:23.533807200 +0300
> @@ -1178,6 +1178,12 @@ recurse_read_control_structure (char * (
> return ret;
> }
>
> +static void
> +restore_interp (void *arg)
> +{
> + interp_set_temp (interp_name ((struct interp *)arg));
> +}
> +
> /* Read lines from the input stream and accumulate them in a chain of
> struct command_line's, which is then returned. For input from a
> terminal, the special command "end" is used to mark the end of the
> @@ -1210,8 +1216,21 @@ read_command_lines (char *prompt_arg, in
> }
> }
>
> - head = read_command_lines_1 (read_next_line, parse_commands,
> - validator, closure);
> +
> + /* Reading commands assumes the CLI behavior, so temporarily
> + override the current interpreter with CLI. */
> + if (current_interp_named_p (INTERP_CONSOLE))
> + head = read_command_lines_1 (read_next_line, parse_commands,
> + validator, closure);
> + else
> + {
> + struct interp *old_interp = interp_set_temp (INTERP_CONSOLE);
> + struct cleanup *old_chain = make_cleanup (restore_interp, old_interp);
> +
> + head = read_command_lines_1 (read_next_line, parse_commands,
> + validator, closure);
> + do_cleanups (old_chain);
> + }
>
> if (deprecated_readline_end_hook && from_tty && input_from_terminal_p ())
> {
>