Files
binutils-gdb/gdb/command.h
Pedro Alves fdbc98707b Introduce the "with" command
( See original discussion and prototype here:
   https://sourceware.org/ml/gdb-patches/2019-05/msg00570.html )

 (gdb) help with
 Temporarily set SETTING to VALUE, run COMMAND, and restore SETTING.
 Usage: with SETTING [VALUE] [-- COMMAND]
 Usage: w SETTING [VALUE] [-- COMMAND]
 With no COMMAND, repeats the last executed command.
 SETTING is any setting you can change with the "set" subcommands.
 E.g.:
   with language pascal -- print obj
   with print elements unlimited -- print obj

As can be seen above, the "with" command is just like "set", but
instead of setting the setting permanently, it sets the setting, runs
a command and then restores the setting.

 (gdb) p g_s
 $1 = {a = 1, b = 2, c = 3}
 (gdb) with language ada -- print g_s
 $2 = (a => 1, b => 2, c => 3)
 Warning: the current language does not match this frame.
 (gdb) show language
 The current source language is "auto; currently c".
 (gdb) with print elements 100 -- with print object on -- print 1
 $3 = 1

You can shorten things a bit though, as long as unambiguous.  So this:

 (gdb) with print elements 100 -- with print object off -- print 1

is the same as:

 (gdb) w p el 100 -- w p o 0 -- p 1

Note that the patch adds a "w" alias for "with", as "w" is not
currently taken:

 (gdb) w
 Ambiguous command "w": watch, wh, whatis, where, while, while-stepping, winheight, ws.

Let me know if you'd prefer to reserve "w" for one of the other
commands above.  IMHO, this command will end up being used frequently
enough that it deserves the "w" shorthand.

A nice feature is that this is fully integrated with TAB-completion:

 (gdb) with p[TAB]
 pagination  print       prompt      python
 (gdb) with print [TAB]
 address                max-depth              static-members
 array                  max-symbolic-offset    symbol
 array-indexes          null-stop              symbol-filename
 asm-demangle           object                 symbol-loading
 demangle               pascal_static-members  thread-events
 elements               pretty                 type
 entry-values           raw                    union
 frame-arguments        repeats                vtbl
 inferior-events        sevenbit-strings
 (gdb) with print [TAB]

 (gdb) with print elements unlimited -- thread apply all -[TAB]
 -ascending  -c          -q          -s

 (gdb) with print elements unlimited -- print -[TAB]
 -address         -max-depth       -repeats         -vtbl
 -array           -null-stop       -static-members
 -array-indexes   -object          -symbol
 -elements        -pretty          -union

The main advantage of this new command compared to command options,
like the new "print -OPT", is that this command works with any
setting, and, it works nicely when you want to override a setting
while running a user-defined command, like:

 (gdb) with print pretty -- usercmd

The disadvantage is that it isn't as compact or easy to type.  I think
of command options and this command as complementary.  I think that
even with this new command, it makes sense to continue developing the
command options in the direction of exposing most-oft-used settings as
command options.

Inspired by Philippe's "/" command proposal, if no command is
specified, then the last command is re-invoked, under the overridden
setting:

 (gdb) p g_s
 $1 = {a = 1, b = 2, c = 3}
 (gdb) with language ada
 $2 = (a => 1, b => 2, c => 3)
 Warning: the current language does not match this frame.

Note: "with" requires "--" to separate the setting from the command.
It might be possible to do without that, but, I haven't tried it yet,
and I think that this can go in without it.  We can always downgrade
to making "--" optional if we manage to make it work.

On to the patch itself, the implementation of the command is simpler
than one might expect.  A few details:

- I factored out a bit from pipe_command into repeat_previous
  directly, because otherwise I'd need to copy&paste the same code and
  same error message in the with command.

- The parse_cli_var_uinteger / parse_cli_var_zuinteger_unlimited /
  do_set_command changes are necessary since we can now pass an empty
  string as argument.

- do_show_command was split in two, as a FIXME comment suggests, but
  for a different reason: we need to get a string version of a "set"
  command's value, and we already had code for that in
  do_show_command.  That code is now factored out to the new
  get_setshow_command_value_string function.

- There's a new "maint with" command added too:

   (gdb) help maint with
   Like "with", but works with "maintenance set" variables.
   Usage: maintenance with SETTING [VALUE] [-- COMMAND]
   With no COMMAND, repeats the last executed command.
   SETTING is any setting you can change with the "maintenance set"
   subcommands.

  "with" and "maint with" share 99% of the implementation.

  This might be useful on its own, but it's also useful for testing,
  since with this, we can use the "maint set/show test-settings"
  settings for exercising the "with" machinery with all the command
  type variants (all enum var_types).  This is done in the new
  gdb/base/with.exp testcase.

The documentation bits are originally based on Philippe's docs for the
"/" command, hence the attribution in the ChangeLog.

gdb/ChangeLog:
2019-07-03  Pedro Alves  <palves@redhat.com>

	* NEWS (New commands): Mention "with" and "maint with".
	* cli/cli-cmds.c (with_command_1, with_command_completer_1)
	(with_command, with_command_completer): New.
	(pipe_command): Adjust to new repeat_previous
	interface.
	(_initialize_cli_cmds): Install the "with" command and its "w"
	alias.
	* cli/cli-cmds.h (with_command_1, with_command_completer_1): New
	declarations.
	* cli/cli-setshow.c (parse_cli_var_uinteger)
	(parse_cli_var_zuinteger_unlimited, do_set_command): Handle empty
	argument strings for all var_types.
	(get_setshow_command_value_string): New, factored out from ...
	(do_show_command): ... this.
	* cli/cli-setshow.h: Include <string>.
	(get_setshow_command_value_string): Declare.
	* command.h (repeat_previous): Now returns const char *.  Adjust
	comment.
	* maint.c: Include "cli/cli-cmds.h".
	(maintenance_with_cmd, maintenance_with_cmd_completer): New.
	(_initialize_maint_cmds): Register the "maintenance with" command.
	* top.c (repeat_previous): Move bits from pipe_command here:
	Return the saved command line, if any; error out if there's no
	command to relaunch.

gdb/doc/ChangeLog:
2019-07-03  Pedro Alves  <palves@redhat.com>
	    Philippe Waroquiers  <philippe.waroquiers@skynet.be>

	* gdb.texinfo (Command Settings): New node documenting the general
	concept of settings, how to change them, and the new "with"
	command.
	(Maintenance Commands): Document "maint with".

gdb/testsuite/ChangeLog:
2019-07-03  Pedro Alves  <palves@redhat.com>

	* gdb.base/with.c: New file.
	* gdb.base/with.exp: New file.
2019-07-03 13:35:45 +01:00

512 lines
18 KiB
C

/* Header file for command creation.
Copyright (C) 1986-2019 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#if !defined (COMMAND_H)
#define COMMAND_H 1
#include "common/gdb_vecs.h"
#include "common/scoped_restore.h"
struct completion_tracker;
/* This file defines the public interface for any code wanting to
create commands. */
/* Command classes are top-level categories into which commands are
broken down for "help" purposes.
Notes on classes: class_alias is for alias commands which are not
abbreviations of the original command. class-pseudo is for
commands which are not really commands nor help topics ("stop"). */
enum command_class
{
/* Special args to help_list */
class_deprecated = -3, all_classes = -2, all_commands = -1,
/* Classes of commands */
no_class = -1, class_run = 0, class_vars, class_stack, class_files,
class_support, class_info, class_breakpoint, class_trace,
class_alias, class_bookmark, class_obscure, class_maintenance,
class_pseudo, class_tui, class_user, class_xdb,
no_set_class /* Used for "show" commands that have no corresponding
"set" command. */
};
/* FIXME: cagney/2002-03-17: Once cmd_type() has been removed, ``enum
cmd_types'' can be moved from "command.h" to "cli-decode.h". */
/* Not a set/show command. Note that some commands which begin with
"set" or "show" might be in this category, if their syntax does
not fall into one of the following categories. */
typedef enum cmd_types
{
not_set_cmd,
set_cmd,
show_cmd
}
cmd_types;
/* Types of "set" or "show" command. */
typedef enum var_types
{
/* "on" or "off". *VAR is an integer which is nonzero for on,
zero for off. */
var_boolean,
/* "on" / "true" / "enable" or "off" / "false" / "disable" or
"auto. *VAR is an ``enum auto_boolean''. NOTE: In general a
custom show command will need to be implemented - one that for
"auto" prints both the "auto" and the current auto-selected
value. */
var_auto_boolean,
/* Unsigned Integer. *VAR is an unsigned int. The user can type
0 to mean "unlimited", which is stored in *VAR as UINT_MAX. */
var_uinteger,
/* Like var_uinteger but signed. *VAR is an int. The user can
type 0 to mean "unlimited", which is stored in *VAR as
INT_MAX. The only remaining use of it is the Python API.
Don't use it elsewhere. */
var_integer,
/* String which the user enters with escapes (e.g. the user types
\n and it is a real newline in the stored string).
*VAR is a malloc'd string, or NULL if the string is empty. */
var_string,
/* String which stores what the user types verbatim.
*VAR is a malloc'd string, or NULL if the string is empty. */
var_string_noescape,
/* String which stores a filename. (*VAR) is a malloc'd string,
or "" if the string was empty. */
var_optional_filename,
/* String which stores a filename. (*VAR) is a malloc'd
string. */
var_filename,
/* ZeroableInteger. *VAR is an int. Like var_integer except
that zero really means zero. */
var_zinteger,
/* ZeroableUnsignedInteger. *VAR is an unsigned int. Zero really
means zero. */
var_zuinteger,
/* ZeroableUnsignedInteger with unlimited value. *VAR is an int,
but its range is [0, INT_MAX]. -1 stands for unlimited and
other negative numbers are not allowed. */
var_zuinteger_unlimited,
/* Enumerated type. Can only have one of the specified values.
*VAR is a char pointer to the name of the element that we
find. */
var_enum
}
var_types;
/* This structure records one command'd definition. */
struct cmd_list_element;
typedef void cmd_const_cfunc_ftype (const char *args, int from_tty);
/* This structure specifies notifications to be suppressed by a cli
command interpreter. */
struct cli_suppress_notification
{
/* Inferior, thread, frame selected notification suppressed? */
int user_selected_context;
};
extern struct cli_suppress_notification cli_suppress_notification;
/* Forward-declarations of the entry-points of cli/cli-decode.c. */
/* API to the manipulation of command lists. */
extern bool valid_user_defined_cmd_name_p (const char *name);
/* Const-correct variant of the above. */
extern struct cmd_list_element *add_cmd (const char *, enum command_class,
cmd_const_cfunc_ftype *fun,
const char *,
struct cmd_list_element **);
/* Like add_cmd, but no command function is specified. */
extern struct cmd_list_element *add_cmd (const char *, enum command_class,
const char *,
struct cmd_list_element **);
extern struct cmd_list_element *add_cmd_suppress_notification
(const char *name, enum command_class theclass,
cmd_const_cfunc_ftype *fun, const char *doc,
struct cmd_list_element **list,
int *suppress_notification);
extern struct cmd_list_element *add_alias_cmd (const char *, const char *,
enum command_class, int,
struct cmd_list_element **);
extern struct cmd_list_element *add_alias_cmd (const char *,
cmd_list_element *,
enum command_class, int,
struct cmd_list_element **);
extern struct cmd_list_element *add_prefix_cmd (const char *, enum command_class,
cmd_const_cfunc_ftype *fun,
const char *,
struct cmd_list_element **,
const char *, int,
struct cmd_list_element **);
extern struct cmd_list_element *add_prefix_cmd_suppress_notification
(const char *name, enum command_class theclass,
cmd_const_cfunc_ftype *fun,
const char *doc, struct cmd_list_element **prefixlist,
const char *prefixname, int allow_unknown,
struct cmd_list_element **list,
int *suppress_notification);
extern struct cmd_list_element *add_abbrev_prefix_cmd (const char *,
enum command_class,
cmd_const_cfunc_ftype *fun,
const char *,
struct cmd_list_element
**, const char *, int,
struct cmd_list_element
**);
typedef void cmd_const_sfunc_ftype (const char *args, int from_tty,
struct cmd_list_element *c);
extern void set_cmd_sfunc (struct cmd_list_element *cmd,
cmd_const_sfunc_ftype *sfunc);
/* A completion routine. Add possible completions to tracker.
TEXT is the text beyond what was matched for the command itself
(leading whitespace is skipped). It stops where we are supposed to
stop completing (rl_point) and is '\0' terminated. WORD points in
the same buffer as TEXT, and completions should be returned
relative to this position. For example, suppose TEXT is "foo" and
we want to complete to "foobar". If WORD is "oo", return "oobar";
if WORD is "baz/foo", return "baz/foobar". */
typedef void completer_ftype (struct cmd_list_element *,
completion_tracker &tracker,
const char *text, const char *word);
/* Same, but for set_cmd_completer_handle_brkchars. */
typedef void completer_handle_brkchars_ftype (struct cmd_list_element *,
completion_tracker &tracker,
const char *text, const char *word);
extern void set_cmd_completer (struct cmd_list_element *, completer_ftype *);
/* Set the completer_handle_brkchars callback. */
extern void set_cmd_completer_handle_brkchars (struct cmd_list_element *,
completer_handle_brkchars_ftype *);
/* HACK: cagney/2002-02-23: Code, mostly in tracepoints.c, grubs
around in cmd objects to test the value of the commands sfunc(). */
extern int cmd_cfunc_eq (struct cmd_list_element *cmd,
cmd_const_cfunc_ftype *cfun);
/* Each command object has a local context attached to it. */
extern void set_cmd_context (struct cmd_list_element *cmd,
void *context);
extern void *get_cmd_context (struct cmd_list_element *cmd);
/* Execute CMD's pre/post hook. Throw an error if the command fails.
If already executing this pre/post hook, or there is no pre/post
hook, the call is silently ignored. */
extern void execute_cmd_pre_hook (struct cmd_list_element *cmd);
extern void execute_cmd_post_hook (struct cmd_list_element *cmd);
/* Return the type of the command. */
extern enum cmd_types cmd_type (struct cmd_list_element *cmd);
/* Flag for an ambiguous cmd_list result. */
#define CMD_LIST_AMBIGUOUS ((struct cmd_list_element *) -1)
extern struct cmd_list_element *lookup_cmd (const char **,
struct cmd_list_element *,
const char *,
int, int);
extern struct cmd_list_element *lookup_cmd_1 (const char **,
struct cmd_list_element *,
struct cmd_list_element **,
int);
extern struct cmd_list_element *deprecate_cmd (struct cmd_list_element *,
const char * );
extern void deprecated_cmd_warning (const char *);
extern int lookup_cmd_composition (const char *text,
struct cmd_list_element **alias,
struct cmd_list_element **prefix_cmd,
struct cmd_list_element **cmd);
extern struct cmd_list_element *add_com (const char *, enum command_class,
cmd_const_cfunc_ftype *fun,
const char *);
extern struct cmd_list_element *add_com_alias (const char *, const char *,
enum command_class, int);
extern struct cmd_list_element *add_com_suppress_notification
(const char *name, enum command_class theclass,
cmd_const_cfunc_ftype *fun, const char *doc,
int *supress_notification);
extern struct cmd_list_element *add_info (const char *,
cmd_const_cfunc_ftype *fun,
const char *);
extern struct cmd_list_element *add_info_alias (const char *, const char *,
int);
extern void complete_on_cmdlist (struct cmd_list_element *,
completion_tracker &tracker,
const char *, const char *, int);
extern void complete_on_enum (completion_tracker &tracker,
const char *const *enumlist,
const char *, const char *);
/* Functions that implement commands about CLI commands. */
extern void help_list (struct cmd_list_element *, const char *,
enum command_class, struct ui_file *);
/* Method for show a set/show variable's VALUE on FILE. If this
method isn't supplied deprecated_show_value_hack() is called (which
is not good). */
typedef void (show_value_ftype) (struct ui_file *file,
int from_tty,
struct cmd_list_element *cmd,
const char *value);
/* NOTE: i18n: This function is not i18n friendly. Callers should
instead print the value out directly. */
extern show_value_ftype deprecated_show_value_hack;
extern void add_setshow_enum_cmd (const char *name,
enum command_class theclass,
const char *const *enumlist,
const char **var,
const char *set_doc,
const char *show_doc,
const char *help_doc,
cmd_const_sfunc_ftype *set_func,
show_value_ftype *show_func,
struct cmd_list_element **set_list,
struct cmd_list_element **show_list,
void *context = nullptr);
extern void add_setshow_auto_boolean_cmd (const char *name,
enum command_class theclass,
enum auto_boolean *var,
const char *set_doc,
const char *show_doc,
const char *help_doc,
cmd_const_sfunc_ftype *set_func,
show_value_ftype *show_func,
struct cmd_list_element **set_list,
struct cmd_list_element **show_list);
extern cmd_list_element *
add_setshow_boolean_cmd (const char *name,
enum command_class theclass,
int *var,
const char *set_doc, const char *show_doc,
const char *help_doc,
cmd_const_sfunc_ftype *set_func,
show_value_ftype *show_func,
struct cmd_list_element **set_list,
struct cmd_list_element **show_list);
extern void add_setshow_filename_cmd (const char *name,
enum command_class theclass,
char **var,
const char *set_doc,
const char *show_doc,
const char *help_doc,
cmd_const_sfunc_ftype *set_func,
show_value_ftype *show_func,
struct cmd_list_element **set_list,
struct cmd_list_element **show_list);
extern void add_setshow_string_cmd (const char *name,
enum command_class theclass,
char **var,
const char *set_doc,
const char *show_doc,
const char *help_doc,
cmd_const_sfunc_ftype *set_func,
show_value_ftype *show_func,
struct cmd_list_element **set_list,
struct cmd_list_element **show_list);
extern struct cmd_list_element *add_setshow_string_noescape_cmd
(const char *name,
enum command_class theclass,
char **var,
const char *set_doc,
const char *show_doc,
const char *help_doc,
cmd_const_sfunc_ftype *set_func,
show_value_ftype *show_func,
struct cmd_list_element **set_list,
struct cmd_list_element **show_list);
extern void add_setshow_optional_filename_cmd (const char *name,
enum command_class theclass,
char **var,
const char *set_doc,
const char *show_doc,
const char *help_doc,
cmd_const_sfunc_ftype *set_func,
show_value_ftype *show_func,
struct cmd_list_element **set_list,
struct cmd_list_element **show_list);
extern void add_setshow_integer_cmd (const char *name,
enum command_class theclass,
int *var,
const char *set_doc,
const char *show_doc,
const char *help_doc,
cmd_const_sfunc_ftype *set_func,
show_value_ftype *show_func,
struct cmd_list_element **set_list,
struct cmd_list_element **show_list);
extern void add_setshow_uinteger_cmd (const char *name,
enum command_class theclass,
unsigned int *var,
const char *set_doc,
const char *show_doc,
const char *help_doc,
cmd_const_sfunc_ftype *set_func,
show_value_ftype *show_func,
struct cmd_list_element **set_list,
struct cmd_list_element **show_list);
extern void add_setshow_zinteger_cmd (const char *name,
enum command_class theclass,
int *var,
const char *set_doc,
const char *show_doc,
const char *help_doc,
cmd_const_sfunc_ftype *set_func,
show_value_ftype *show_func,
struct cmd_list_element **set_list,
struct cmd_list_element **show_list);
extern void add_setshow_zuinteger_cmd (const char *name,
enum command_class theclass,
unsigned int *var,
const char *set_doc,
const char *show_doc,
const char *help_doc,
cmd_const_sfunc_ftype *set_func,
show_value_ftype *show_func,
struct cmd_list_element **set_list,
struct cmd_list_element **show_list);
extern void
add_setshow_zuinteger_unlimited_cmd (const char *name,
enum command_class theclass,
int *var,
const char *set_doc,
const char *show_doc,
const char *help_doc,
cmd_const_sfunc_ftype *set_func,
show_value_ftype *show_func,
struct cmd_list_element **set_list,
struct cmd_list_element **show_list);
/* Do a "show" command for each thing on a command list. */
extern void cmd_show_list (struct cmd_list_element *, int, const char *);
/* Used everywhere whenever at least one parameter is required and
none is specified. */
extern void error_no_arg (const char *) ATTRIBUTE_NORETURN;
/* Command line saving and repetition.
Each input line executed is saved to possibly be repeated either
when the user types an empty line, or be repeated by a command
that wants to repeat the previously executed command. The below
functions control command repetition. */
/* Commands call dont_repeat if they do not want to be repeated by null
lines or by repeat_previous (). */
extern void dont_repeat ();
/* Commands call repeat_previous if they want to repeat the previous
command. Such commands that repeat the previous command must
indicate to not repeat themselves, to avoid recursive repeat.
repeat_previous marks the current command as not repeating, and
ensures get_saved_command_line returns the previous command, so
that the currently executing command can repeat it. If there's no
previous command, throws an error. Otherwise, returns the result
of get_saved_command_line, which now points at the command to
repeat. */
extern const char *repeat_previous ();
/* Prevent dont_repeat from working, and return a cleanup that
restores the previous state. */
extern scoped_restore_tmpl<int> prevent_dont_repeat (void);
/* Set the arguments that will be passed if the current command is
repeated. Note that the passed-in string must be a constant. */
extern void set_repeat_arguments (const char *args);
/* Returns the saved command line to repeat.
When a command is being executed, this is the currently executing
command line, unless the currently executing command has called
repeat_previous (): in this case, get_saved_command_line returns
the previously saved command line. */
extern char *get_saved_command_line ();
/* Takes a copy of CMD, for possible repetition. */
extern void save_command_line (const char *cmd);
/* Used to mark commands that don't do anything. If we just leave the
function field NULL, the command is interpreted as a help topic, or
as a class of commands. */
extern void not_just_help_class_command (const char *, int);
/* Check function pointer. */
extern int cmd_func_p (struct cmd_list_element *cmd);
/* Call the command function. */
extern void cmd_func (struct cmd_list_element *cmd,
const char *args, int from_tty);
#endif /* !defined (COMMAND_H) */