8sa1-binutils-gdb/gdb/cli/cli-setshow.c
Pedro Alves 9d0faba9f5 Introduce generic command options framework
This commit adds a generic command options framework, that makes it
easy enough to add '-'-style options to commands in a uniform way,
instead of each command implementing option parsing in its own way.

Options are defined in arrays of option_def objects (for option
definition), and the same options definitions are used for supporting
TAB completion, and also for generating the relevant help fragment of
the "help" command.  See the gdb::options::build_help function, which
returns a string with the result of replacing %OPTIONS% in a template
string with an auto-generated "help" string fragment for all the
passed-in options.

Since most options in GDB are in the form of "-OPT", with a single
dash, this is the format that the framework supports.

I like to think of gdb's "-OPT" as the equivalent to getopt's long
options format ("--OPT"), and gdb's "/" as the equivalent to getopt's
short options format.  getopt's short options format allows mixing
several one-character options, like "ls -als", kind of similar to
gdb's "x /FMT" and "disassemble /MOD", etc.  While with gdb's "-"
options, the option is expected to have a full name, and to be
abbreviatable.  E.g., "watch -location", "break -function main", etc.

This patch only deals with "-" options.  The above comment serves more
to disclose why I don't think we should support mixing several
unrelated options in a single "-" option invocation, like "thread
apply -qcs" instead of "thread apply -q -c -s".

The following patches will add uses of the infrastructure to several
key commands.  Most notably, "print", "compile print", "backtrace",
"frame apply" and "thread apply".  I tried to add options to several
commands in order to make sure the framework didn't leave that many
open holes open.

Options use the same type as set commands -- enum var_types.  So
boolean options are var_boolean, enum options are var_enum, etc.  The
idea is to share code between settings commands and command options.
The "print" options will be based on the "set print" commands, and
their names will be the same.  Actually, their definitions will be the
same too.  There is a function to create "set/show" commands from an
array for option definitions:

 /* Install set/show commands for options defined in OPTIONS.  DATA is
    a pointer to the structure that holds the data associated with the
    OPTIONS array.  */
 extern void add_setshow_cmds_for_options (command_class cmd_class, void *data,
					   gdb::array_view<const option_def> options,
					   struct cmd_list_element **set_list,
					   struct cmd_list_element **show_list);

That will be used by several following patches.

Other features:

 - You can use the "--" delimiter to explicitly indicate end of
   options.  Several existing commands use this token sequence for
   this effect already, so this just standardizes it.

 - You can shorten option names, as long as unambiguous.  Currently,
   some commands allow this (e.g., break -function), while others do
   not (thread apply all -ascending).  As GDB allows abbreviating
   command names and other things, it feels more GDB-ish to allow
   abbreviating option names too, to me.

 - For boolean options, 0/1 stands for off/on, just like with boolean
   "set" commands.

 - For boolean options, "true" is implied, just like with boolean "set
   commands.

These are the option types supported, with a few examples:

 - boolean options (var_boolean).  The option's argument is optional.

   (gdb) print -pretty on -- *obj
   (gdb) print -pretty off -- *obj
   (gdb) print -p -- *obj
   (gdb) print -p 0 -- *obj

 - flag options (like var_boolean, but no option argument (on/off))

   (gdb) thread apply all -s COMMAND

 - enum options  (var_enum)

   (gdb) bt -entry-values compact
   (gdb) bt -e c

 - uinteger options (var_uinteger)

   (gdb) print -elements 100 -- *obj
   (gdb) print -e 100 -- *obj
   (gdb) print -elements unlimited -- *obj
   (gdb) print -e u -- *obj

 - zuinteger-unlimited options (var_zuinteger_unlimited)

   (gdb) print -max-depth 100 -- obj
   (gdb) print -max-depth -1 -- obj
   (gdb) print -max-depth unlimited -- obj

Other var_types could be supported, of course.  These were just the
types that I needed for the commands that I ported over, in the
following patches.

It was interesting (and unfortunate) to find that we need at least 3
different modes to cover the existing commands:

- Commands that require ending options with "--" if you specify any
  option: "print" and "compile print".

- Commands that do not want to require "--", and want to error out if
  you specify an unknown option (i.e., an unknown argument that starts
  with '-'): "compile code" / "compile file".

- Commands that do not want to require "--", and want to process
  unknown options themselves: "bt", because of "bt -COUNT",
  "thread/frame apply", because "-" is a valid command.

The different behavior is encoded in the process_options_mode enum,
passed to process_options/complete_options.

For testing, this patch adds one representative maintenance command
for each of the process_options_mode values, that are used by the
testsuite to exercise the options framework:

 (gdb) maint test-options require-delimiter
 (gdb) maint test-options unknown-is-error
 (gdb) maint test-options unknown-is-operand

and adds another command to help with TAB-completion testing:

 (gdb) maint show test-options-completion-result

See their description at the top of the maint-test-options.c file.

Docs/NEWS are in a patch later in the series.

gdb/ChangeLog:
2019-06-13  Pedro Alves  <palves@redhat.com>

	* Makefile.in (SUBDIR_CLI_SRCS): Add cli/cli-option.c.
	(COMMON_SFILES): Add maint-test-settings.c.
	* cli/cli-decode.c (boolean_enums): New global, factored out from
	...
	(add_setshow_boolean_cmd): ... here.
	* cli/cli-decode.h (boolean_enums): Declare.
	* cli/cli-option.c: New file.
	* cli/cli-option.h: New file.
	* cli/cli-setshow.c (parse_cli_boolean_value(const char **)): New,
	factored out from ...
	(parse_cli_boolean_value(const char *)): ... this.
	(is_unlimited_literal): Change parameter type to pointer to
	pointer.  Adjust and advance ARG pointer.
	(parse_cli_var_uinteger, parse_cli_var_zuinteger_unlimited)
	(parse_cli_var_enum): New, factored out from ...
	(do_set_command): ... this.  Adjust.
	* cli/cli-setshow.h (parse_cli_boolean_value)
	(parse_cli_var_uinteger, parse_cli_var_zuinteger_unlimited)
	(parse_cli_var_enum): Declare.
	* cli/cli-utils.c: Include "cli/cli-option.h".
	(get_ulongest): New.
	* cli/cli-utils.h (get_ulongest): Declare.
	(check_for_argument): New overloads.
	* maint-test-options.c: New file.

gdb/testsuite/ChangeLog:
2019-06-13  Pedro Alves  <palves@redhat.com>

	* gdb.base/options.c: New file.
	* gdb.base/options.exp: New file.
2019-06-13 00:18:12 +01:00

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/* Handle set and show GDB commands.
Copyright (C) 2000-2019 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/>. */
#include "defs.h"
#include "readline/tilde.h"
#include "value.h"
#include <ctype.h>
#include "arch-utils.h"
#include "observable.h"
#include "ui-out.h"
#include "cli/cli-decode.h"
#include "cli/cli-cmds.h"
#include "cli/cli-setshow.h"
#include "cli/cli-utils.h"
/* Return true if the change of command parameter should be notified. */
static int
notify_command_param_changed_p (int param_changed, struct cmd_list_element *c)
{
if (param_changed == 0)
return 0;
if (c->theclass == class_maintenance || c->theclass == class_deprecated
|| c->theclass == class_obscure)
return 0;
return 1;
}
static enum auto_boolean
parse_auto_binary_operation (const char *arg)
{
if (arg != NULL && *arg != '\0')
{
int length = strlen (arg);
while (isspace (arg[length - 1]) && length > 0)
length--;
/* Note that "o" is ambiguous. */
if ((length == 2 && strncmp (arg, "on", length) == 0)
|| strncmp (arg, "1", length) == 0
|| strncmp (arg, "yes", length) == 0
|| strncmp (arg, "enable", length) == 0)
return AUTO_BOOLEAN_TRUE;
else if ((length >= 2 && strncmp (arg, "off", length) == 0)
|| strncmp (arg, "0", length) == 0
|| strncmp (arg, "no", length) == 0
|| strncmp (arg, "disable", length) == 0)
return AUTO_BOOLEAN_FALSE;
else if (strncmp (arg, "auto", length) == 0
|| (length > 1 && strncmp (arg, "-1", length) == 0))
return AUTO_BOOLEAN_AUTO;
}
error (_("\"on\", \"off\" or \"auto\" expected."));
return AUTO_BOOLEAN_AUTO; /* Pacify GCC. */
}
/* See cli-setshow.h. */
int
parse_cli_boolean_value (const char **arg)
{
const char *p = skip_to_space (*arg);
size_t length = p - *arg;
/* Note that "o" is ambiguous. */
if ((length == 2 && strncmp (*arg, "on", length) == 0)
|| strncmp (*arg, "1", length) == 0
|| strncmp (*arg, "yes", length) == 0
|| strncmp (*arg, "enable", length) == 0)
{
*arg = skip_spaces (*arg + length);
return 1;
}
else if ((length >= 2 && strncmp (*arg, "off", length) == 0)
|| strncmp (*arg, "0", length) == 0
|| strncmp (*arg, "no", length) == 0
|| strncmp (*arg, "disable", length) == 0)
{
*arg = skip_spaces (*arg + length);
return 0;
}
else
return -1;
}
/* See cli-setshow.h. */
int
parse_cli_boolean_value (const char *arg)
{
if (!arg || !*arg)
return 1;
int b = parse_cli_boolean_value (&arg);
if (b >= 0 && *arg != '\0')
return -1;
return b;
}
void
deprecated_show_value_hack (struct ui_file *ignore_file,
int ignore_from_tty,
struct cmd_list_element *c,
const char *value)
{
/* If there's no command or value, don't try to print it out. */
if (c == NULL || value == NULL)
return;
/* Print doc minus "show" at start. */
print_doc_line (gdb_stdout, c->doc + 5);
switch (c->var_type)
{
case var_string:
case var_string_noescape:
case var_optional_filename:
case var_filename:
case var_enum:
printf_filtered ((" is \"%s\".\n"), value);
break;
default:
printf_filtered ((" is %s.\n"), value);
break;
}
}
/* Returns true if ARG is "unlimited". */
static bool
is_unlimited_literal (const char **arg)
{
*arg = skip_spaces (*arg);
const char *p = skip_to_space (*arg);
size_t len = p - *arg;
if (len > 0 && strncmp ("unlimited", *arg, len) == 0)
{
*arg += len;
return true;
}
return false;
}
/* See cli-setshow.h. */
unsigned int
parse_cli_var_uinteger (var_types var_type, const char **arg,
bool expression)
{
LONGEST val;
if (*arg == nullptr)
{
if (var_type == var_uinteger)
error_no_arg (_("integer to set it to, or \"unlimited\"."));
else
error_no_arg (_("integer to set it to."));
}
if (var_type == var_uinteger && is_unlimited_literal (arg))
val = 0;
else if (expression)
val = parse_and_eval_long (*arg);
else
val = get_ulongest (arg);
if (var_type == var_uinteger && val == 0)
val = UINT_MAX;
else if (val < 0
/* For var_uinteger, don't let the user set the value
to UINT_MAX directly, as that exposes an
implementation detail to the user interface. */
|| (var_type == var_uinteger && val >= UINT_MAX)
|| (var_type == var_zuinteger && val > UINT_MAX))
error (_("integer %s out of range"), plongest (val));
return val;
}
/* See cli-setshow.h. */
int
parse_cli_var_zuinteger_unlimited (const char **arg, bool expression)
{
LONGEST val;
if (*arg == nullptr)
error_no_arg (_("integer to set it to, or \"unlimited\"."));
if (is_unlimited_literal (arg))
val = -1;
else if (expression)
val = parse_and_eval_long (*arg);
else
val = get_ulongest (arg);
if (val > INT_MAX)
error (_("integer %s out of range"), plongest (val));
else if (val < -1)
error (_("only -1 is allowed to set as unlimited"));
return val;
}
/* See cli-setshow.h. */
const char *
parse_cli_var_enum (const char **args, const char *const *enums)
{
/* If no argument was supplied, print an informative error
message. */
if (args == NULL || *args == NULL || **args == '\0')
{
std::string msg;
for (size_t i = 0; enums[i]; i++)
{
if (i != 0)
msg += ", ";
msg += enums[i];
}
error (_("Requires an argument. Valid arguments are %s."),
msg.c_str ());
}
const char *p = skip_to_space (*args);
size_t len = p - *args;
int nmatches = 0;
const char *match = NULL;
for (size_t i = 0; enums[i]; i++)
if (strncmp (*args, enums[i], len) == 0)
{
if (enums[i][len] == '\0')
{
match = enums[i];
nmatches = 1;
break; /* Exact match. */
}
else
{
match = enums[i];
nmatches++;
}
}
if (nmatches == 0)
error (_("Undefined item: \"%.*s\"."), (int) len, *args);
if (nmatches > 1)
error (_("Ambiguous item \"%.*s\"."), (int) len, *args);
*args += len;
return match;
}
/* Do a "set" command. ARG is NULL if no argument, or the
text of the argument, and FROM_TTY is nonzero if this command is
being entered directly by the user (i.e. these are just like any
other command). C is the command list element for the command. */
void
do_set_command (const char *arg, int from_tty, struct cmd_list_element *c)
{
/* A flag to indicate the option is changed or not. */
int option_changed = 0;
gdb_assert (c->type == set_cmd);
switch (c->var_type)
{
case var_string:
{
char *newobj;
const char *p;
char *q;
int ch;
if (arg == NULL)
arg = "";
newobj = (char *) xmalloc (strlen (arg) + 2);
p = arg;
q = newobj;
while ((ch = *p++) != '\000')
{
if (ch == '\\')
{
/* \ at end of argument is used after spaces
so they won't be lost. */
/* This is obsolete now that we no longer strip
trailing whitespace and actually, the backslash
didn't get here in my test, readline or
something did something funky with a backslash
right before a newline. */
if (*p == 0)
break;
ch = parse_escape (get_current_arch (), &p);
if (ch == 0)
break; /* C loses */
else if (ch > 0)
*q++ = ch;
}
else
*q++ = ch;
}
#if 0
if (*(p - 1) != '\\')
*q++ = ' ';
#endif
*q++ = '\0';
newobj = (char *) xrealloc (newobj, q - newobj);
if (*(char **) c->var == NULL
|| strcmp (*(char **) c->var, newobj) != 0)
{
xfree (*(char **) c->var);
*(char **) c->var = newobj;
option_changed = 1;
}
else
xfree (newobj);
}
break;
case var_string_noescape:
if (arg == NULL)
arg = "";
if (*(char **) c->var == NULL || strcmp (*(char **) c->var, arg) != 0)
{
xfree (*(char **) c->var);
*(char **) c->var = xstrdup (arg);
option_changed = 1;
}
break;
case var_filename:
if (arg == NULL)
error_no_arg (_("filename to set it to."));
/* FALLTHROUGH */
case var_optional_filename:
{
char *val = NULL;
if (arg != NULL)
{
/* Clear trailing whitespace of filename. */
const char *ptr = arg + strlen (arg) - 1;
char *copy;
while (ptr >= arg && (*ptr == ' ' || *ptr == '\t'))
ptr--;
copy = xstrndup (arg, ptr + 1 - arg);
val = tilde_expand (copy);
xfree (copy);
}
else
val = xstrdup ("");
if (*(char **) c->var == NULL
|| strcmp (*(char **) c->var, val) != 0)
{
xfree (*(char **) c->var);
*(char **) c->var = val;
option_changed = 1;
}
else
xfree (val);
}
break;
case var_boolean:
{
int val = parse_cli_boolean_value (arg);
if (val < 0)
error (_("\"on\" or \"off\" expected."));
if (val != *(int *) c->var)
{
*(int *) c->var = val;
option_changed = 1;
}
}
break;
case var_auto_boolean:
{
enum auto_boolean val = parse_auto_binary_operation (arg);
if (*(enum auto_boolean *) c->var != val)
{
*(enum auto_boolean *) c->var = val;
option_changed = 1;
}
}
break;
case var_uinteger:
case var_zuinteger:
{
unsigned int val = parse_cli_var_uinteger (c->var_type, &arg, true);
if (*(unsigned int *) c->var != val)
{
*(unsigned int *) c->var = val;
option_changed = 1;
}
}
break;
case var_integer:
case var_zinteger:
{
LONGEST val;
if (arg == NULL)
{
if (c->var_type == var_integer)
error_no_arg (_("integer to set it to, or \"unlimited\"."));
else
error_no_arg (_("integer to set it to."));
}
if (c->var_type == var_integer && is_unlimited_literal (&arg))
val = 0;
else
val = parse_and_eval_long (arg);
if (val == 0 && c->var_type == var_integer)
val = INT_MAX;
else if (val < INT_MIN
/* For var_integer, don't let the user set the value
to INT_MAX directly, as that exposes an
implementation detail to the user interface. */
|| (c->var_type == var_integer && val >= INT_MAX)
|| (c->var_type == var_zinteger && val > INT_MAX))
error (_("integer %s out of range"), plongest (val));
if (*(int *) c->var != val)
{
*(int *) c->var = val;
option_changed = 1;
}
break;
}
case var_enum:
{
const char *end_arg = arg;
const char *match = parse_cli_var_enum (&end_arg, c->enums);
int len = end_arg - arg;
const char *after = skip_spaces (end_arg);
if (*after != '\0')
error (_("Junk after item \"%.*s\": %s"), len, arg, after);
if (*(const char **) c->var != match)
{
*(const char **) c->var = match;
option_changed = 1;
}
}
break;
case var_zuinteger_unlimited:
{
int val = parse_cli_var_zuinteger_unlimited (&arg, true);
if (*(int *) c->var != val)
{
*(int *) c->var = val;
option_changed = 1;
}
}
break;
default:
error (_("gdb internal error: bad var_type in do_setshow_command"));
}
c->func (c, NULL, from_tty);
if (notify_command_param_changed_p (option_changed, c))
{
char *name, *cp;
struct cmd_list_element **cmds;
struct cmd_list_element *p;
int i;
int length = 0;
/* Compute the whole multi-word command options. If user types command
'set foo bar baz on', c->name is 'baz', and GDB can't pass "bar" to
command option change notification, because it is confusing. We can
trace back through field 'prefix' to compute the whole options,
and pass "foo bar baz" to notification. */
for (i = 0, p = c; p != NULL; i++)
{
length += strlen (p->name);
length++;
p = p->prefix;
}
cp = name = (char *) xmalloc (length);
cmds = XNEWVEC (struct cmd_list_element *, i);
/* Track back through filed 'prefix' and cache them in CMDS. */
for (i = 0, p = c; p != NULL; i++)
{
cmds[i] = p;
p = p->prefix;
}
/* Don't trigger any observer notification if prefixlist is not
setlist. */
i--;
if (cmds[i]->prefixlist != &setlist)
{
xfree (cmds);
xfree (name);
return;
}
/* Traverse them in the reversed order, and copy their names into
NAME. */
for (i--; i >= 0; i--)
{
memcpy (cp, cmds[i]->name, strlen (cmds[i]->name));
cp += strlen (cmds[i]->name);
if (i != 0)
{
cp[0] = ' ';
cp++;
}
}
cp[0] = 0;
xfree (cmds);
switch (c->var_type)
{
case var_string:
case var_string_noescape:
case var_filename:
case var_optional_filename:
case var_enum:
gdb::observers::command_param_changed.notify (name, *(char **) c->var);
break;
case var_boolean:
{
const char *opt = *(int *) c->var ? "on" : "off";
gdb::observers::command_param_changed.notify (name, opt);
}
break;
case var_auto_boolean:
{
const char *s = auto_boolean_enums[*(enum auto_boolean *) c->var];
gdb::observers::command_param_changed.notify (name, s);
}
break;
case var_uinteger:
case var_zuinteger:
{
char s[64];
xsnprintf (s, sizeof s, "%u", *(unsigned int *) c->var);
gdb::observers::command_param_changed.notify (name, s);
}
break;
case var_integer:
case var_zinteger:
case var_zuinteger_unlimited:
{
char s[64];
xsnprintf (s, sizeof s, "%d", *(int *) c->var);
gdb::observers::command_param_changed.notify (name, s);
}
break;
}
xfree (name);
}
}
/* Do a "show" command. ARG is NULL if no argument, or the
text of the argument, and FROM_TTY is nonzero if this command is
being entered directly by the user (i.e. these are just like any
other command). C is the command list element for the command. */
void
do_show_command (const char *arg, int from_tty, struct cmd_list_element *c)
{
struct ui_out *uiout = current_uiout;
gdb_assert (c->type == show_cmd);
string_file stb;
/* Possibly call the pre hook. */
if (c->pre_show_hook)
(c->pre_show_hook) (c);
switch (c->var_type)
{
case var_string:
if (*(char **) c->var)
stb.putstr (*(char **) c->var, '"');
break;
case var_string_noescape:
case var_optional_filename:
case var_filename:
case var_enum:
if (*(char **) c->var)
stb.puts (*(char **) c->var);
break;
case var_boolean:
stb.puts (*(int *) c->var ? "on" : "off");
break;
case var_auto_boolean:
switch (*(enum auto_boolean*) c->var)
{
case AUTO_BOOLEAN_TRUE:
stb.puts ("on");
break;
case AUTO_BOOLEAN_FALSE:
stb.puts ("off");
break;
case AUTO_BOOLEAN_AUTO:
stb.puts ("auto");
break;
default:
internal_error (__FILE__, __LINE__,
_("do_show_command: "
"invalid var_auto_boolean"));
break;
}
break;
case var_uinteger:
case var_zuinteger:
if (c->var_type == var_uinteger
&& *(unsigned int *) c->var == UINT_MAX)
stb.puts ("unlimited");
else
stb.printf ("%u", *(unsigned int *) c->var);
break;
case var_integer:
case var_zinteger:
if (c->var_type == var_integer
&& *(int *) c->var == INT_MAX)
stb.puts ("unlimited");
else
stb.printf ("%d", *(int *) c->var);
break;
case var_zuinteger_unlimited:
{
if (*(int *) c->var == -1)
stb.puts ("unlimited");
else
stb.printf ("%d", *(int *) c->var);
}
break;
default:
error (_("gdb internal error: bad var_type in do_show_command"));
}
/* FIXME: cagney/2005-02-10: Need to split this in half: code to
convert the value into a string (esentially the above); and
code to print the value out. For the latter there should be
MI and CLI specific versions. */
if (uiout->is_mi_like_p ())
uiout->field_stream ("value", stb);
else
{
if (c->show_value_func != NULL)
c->show_value_func (gdb_stdout, from_tty, c, stb.c_str ());
else
deprecated_show_value_hack (gdb_stdout, from_tty, c, stb.c_str ());
}
c->func (c, NULL, from_tty);
}
/* Show all the settings in a list of show commands. */
void
cmd_show_list (struct cmd_list_element *list, int from_tty, const char *prefix)
{
struct ui_out *uiout = current_uiout;
ui_out_emit_tuple tuple_emitter (uiout, "showlist");
for (; list != NULL; list = list->next)
{
/* If we find a prefix, run its list, prefixing our output by its
prefix (with "show " skipped). */
if (list->prefixlist && !list->abbrev_flag)
{
ui_out_emit_tuple optionlist_emitter (uiout, "optionlist");
const char *new_prefix = strstr (list->prefixname, "show ") + 5;
if (uiout->is_mi_like_p ())
uiout->field_string ("prefix", new_prefix);
cmd_show_list (*list->prefixlist, from_tty, new_prefix);
}
else
{
if (list->theclass != no_set_class)
{
ui_out_emit_tuple option_emitter (uiout, "option");
uiout->text (prefix);
uiout->field_string ("name", list->name);
uiout->text (": ");
if (list->type == show_cmd)
do_show_command ((char *) NULL, from_tty, list);
else
cmd_func (list, NULL, from_tty);
}
}
}
}