Re: [PATCH] gdb: multi-line support for "document" command

[Simon Marchi <simark@simark.ca>]

On 2020-11-28 9:24 a.m., Rae Kim via Gdb-patches wrote:
> "document" command executed in python, gdb.execute("document
> <comname>\n...\nend\n"), will wait for user input. Python extension stops
> working from that point.
>
> "define" command works well with gdb.execute(). Looks like, when multi-line
> support was first introdued in commit 56bcdbea2b, "document" was left out.
>
> I checked the way "define" handles multi-line mode. And applied it to
> "document" command.

Hi,

Thanks for the patch.  I noted some small nits to fix below.  Also, it
would be good to have a test for this.  You can inspire yourself from
commit 56bcdbea2b and add a gdb.execute that defines a command, another
one that documents it, and then verify that they both worked.

Some tips for the ChangeLog:

> gdb/ChangeLog:
> 2020-11-28  Rae Kim  <rae.kim@gmail.com>
>
>         * gdb/cli/cli-script.c (do_document_command): Renamed from

Remove the leading "gdb/".

>         * document_command() and handles multi-line input

Remove the leading "* ", and the parenthesis after document_command.

Use the present tense, imperative form: "Rename from document_command
and handle multi-line input".  Don't forget a period at the end.  Apply
below too.

>         (multi_line_command_p): Handles document_control.
>         (build_command_line): Likewise.
>         (execute_control_command_1): Likewise.
>         (process_next_line): Likewise.
>         (document_command): Calls do_document_command with.
>         * gdb/cli/cli-script.h (enum command_control_type): Added
>         document_control.
> ---
>  gdb/cli/cli-script.c | 42 ++++++++++++++++++++++++++++++++++++++----
>  gdb/cli/cli-script.h |  1 +
>  2 files changed, 39 insertions(+), 4 deletions(-)
>
> diff --git a/gdb/cli/cli-script.c b/gdb/cli/cli-script.c
> index afa44af95a..25807080e5 100644
> --- a/gdb/cli/cli-script.c
> +++ b/gdb/cli/cli-script.c
> @@ -51,6 +51,9 @@ recurse_read_control_structure
>  static void do_define_command (const char *comname, int from_tty,
>  			       const counted_command_line *commands);
>
> +static void do_document_command (const char *comname, int from_tty,
> +			       const counted_command_line *commands);

The second line of parameters should be aligned with the first line of
parameters, so it's missing two columns.  So it should be indented with
4 tabs and 1 space here.

> +
>  static const char *read_next_line ();
>
>  /* Level of control structure when reading.  */
> @@ -71,6 +74,9 @@ static cmd_list_element *if_cmd_element = nullptr;
>  /* Command element for the 'define' command.  */
>  static cmd_list_element *define_cmd_element = nullptr;
>
> +/* Command element for the 'document' command.  */
> +static cmd_list_element *document_cmd_element = nullptr;
> +
>  /* Structure for arguments to user defined functions.  */
>
>  class user_args
> @@ -139,6 +145,7 @@ multi_line_command_p (enum command_control_type type)
>      case python_control:
>      case guile_control:
>      case define_control:
> +    case document_control:
>        return 1;
>      default:
>        return 0;
> @@ -159,6 +166,8 @@ build_command_line (enum command_control_type type, const char *args)
>  	error (_("while command requires an argument."));
>        else if (type == define_control)
>  	error (_("define command requires an argument."));
> +      else if (type == document_control)
> +	error (_("document command requires an argument."));
>      }
>    gdb_assert (args != NULL);
>
> @@ -679,6 +688,12 @@ execute_control_command_1 (struct command_line *cmd, int from_tty)
>        ret = simple_control;
>        break;
>
> +    case document_control:
> +      print_command_trace ("document %s", cmd->line);
> +      do_document_command (cmd->line, 0, &cmd->body_list_0);
> +      ret = simple_control;
> +      break;
> +
>      case python_control:
>      case guile_control:
>        {
> @@ -1019,6 +1034,8 @@ process_next_line (const char *p, struct command_line **command,
>  	*command = build_command_line (commands_control, line_first_arg (p));
>        else if (cmd == define_cmd_element)
>  	*command = build_command_line (define_control, line_first_arg (p));
> +      else if (cmd == document_cmd_element)
> +	*command = build_command_line (document_control, line_first_arg (p));
>        else if (cmd == python_cmd_element && !inline_cmd)
>  	{
>  	  /* Note that we ignore the inline "python command" form
> @@ -1508,8 +1525,13 @@ define_command (const char *comname, int from_tty)
>    do_define_command (comname, from_tty, nullptr);
>  }
>
> +/* Document a user-defined command.  If COMMANDS is NULL, then this is a
> +   top-level call and the document will be read using read_command_lines.
> +   Otherwise, it is a "document" command in an existing command and the
> +   commands are provided. */

Use two spaces after the last period too.

>  static void
> -document_command (const char *comname, int from_tty)
> +do_document_command (const char *comname, int from_tty,
> +		   const counted_command_line *commands)

Align second line of parameters with the first one.

>  {
>    struct cmd_list_element *c, **list;
>    const char *tem;
> @@ -1526,8 +1548,14 @@ document_command (const char *comname, int from_tty)
>
>    std::string prompt = string_printf ("Type documentation for \"%s\".",
>  				      comfull);

Move this string into the `if (commands == nullptr)`, as is done in
do_define_command.

> -  counted_command_line doclines = read_command_lines (prompt.c_str (),
> +
> +  counted_command_line doclines;
> +
> +  if (commands == nullptr)
> +      doclines = read_command_lines (prompt.c_str (),
>  						      from_tty, 0, 0);
> +  else
> +      doclines = *commands;
>
>    xfree ((char *) c->doc);
>
> @@ -1553,6 +1581,12 @@ document_command (const char *comname, int from_tty)
>    }
>  }
>
> +static void
> +document_command (const char *comname, int from_tty)
> +{
> +  do_document_command (comname, from_tty, nullptr);
> +}
> +
>  /* Implementation of the "define-prefix" command.  */
>
>  static void
> @@ -1676,11 +1710,11 @@ _initialize_cli_script ()
>    /* "document", "define" and "define-prefix" use command_completer,
>       as this helps the user to either type the command name and/or
>       its prefixes.  */
> -  c = add_com ("document", class_support, document_command, _("\
> +  document_cmd_element = add_com ("document", class_support, document_command, _("\

This line is now too long, please wrap it.

Simon