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binutils-gdb/gdb/maint-test-options.c
Simon Marchi e0700ba44c gdb: make string-like set show commands use std::string variable 
String-like settings (var_string, var_filename, var_optional_filename,
var_string_noescape) currently take a pointer to a `char *` storage
variable (typically global) that holds the setting's value.  I'd like to
"mordernize" this by changing them to use an std::string for storage.

An obvious reason is that string operations on std::string are often
easier to write than with C strings.  And they avoid having to do any
manual memory management.

Another interesting reason is that, with `char *`, nullptr and an empty
string often both have the same meaning of "no value".  String settings
are initially nullptr (unless initialized otherwise).  But when doing
"set foo" (where `foo` is a string setting), the setting now points to
an empty string.  For example, solib_search_path is nullptr at startup,
but points to an empty string after doing "set solib-search-path".  This
leads to some code that needs to check for both to check for "no value".
Or some code that converts back and forth between NULL and "" when
getting or setting the value.  I find this very error-prone, because it
is very easy to forget one or the other.  With std::string, we at least
know that the variable is not "NULL".  There is only one way of
representing an empty string setting, that is with an empty string.

I was wondering whether the distinction between NULL and "" would be
important for some setting, but it doesn't seem so.  If that ever
happens, it would be more C++-y and self-descriptive to use
optional<string> anyway.

Actually, there's one spot where this distinction mattered, it's in
init_history, for the test gdb.base/gdbinit-history.exp.  init_history
sets the history filename to the default ".gdb_history" if it sees that
the setting was never set - if history_filename is nullptr.  If
history_filename is an empty string, it means the setting was explicitly
cleared, so it leaves it as-is.  With the change to std::string, this
distinction doesn't exist anymore.  This can be fixed by moving the code
that chooses a good default value for history_filename to
_initialize_top.  This is ran before -ex commands are processed, so an
-ex command can then clear that value if needed (what
gdb.base/gdbinit-history.exp tests).

Another small improvement, in my opinion is that we can now easily
give string parameters initial values, by simply initializing the global
variables, instead of xstrdup-ing it in the _initialize function.

In Python and Guile, when registering a string-like parameter, we
allocate (with new) an std::string that is owned by the param_smob (in
Guile) and the parmpy_object (in Python) objects.

This patch started by changing all relevant add_setshow_* commands to
take an `std::string *` instead of a `char **` and fixing everything
that failed to build.  That includes of course all string setting
variable and their uses.

string_option_def now uses an std::string also, because there's a
connection between options and settings (see
add_setshow_cmds_for_options).

The add_path function in source.c is really complex and twisted, I'd
rather not try to change it to work on an std::string right now.
Instead, I added an overload that copies the std:string to a `char *`
and back.  This means more copying, but this is not used in a hot path
at all, so I think it is acceptable.

Change-Id: I92c50a1bdd8307141cdbacb388248e4e4fc08c93
Co-authored-by: Lancelot SIX <lsix@lancelotsix.com>
2021-10-03 17:53:16 +01:00

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/* Maintenance commands for testing the options framework.
Copyright (C) 2019-2021 Free Software Foundation, Inc.
This file is part of GDB.
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 "gdbcmd.h"
#include "cli/cli-option.h"
/* This file defines three "maintenance test-options" subcommands to
exercise TAB-completion and option processing:
(gdb) maint test-options require-delimiter
(gdb) maint test-options unknown-is-error
(gdb) maint test-options unknown-is-operand
And a fourth one to help with TAB-completion testing.
(gdb) maint show test-options-completion-result
Each of the test-options subcommands exercise
gdb::option::process_options with a different enum
process_options_mode value. Examples for commands they model:
- "print" and "compile print", are like "require-delimiter",
because they accept random expressions as argument.
- "backtrace" and "frame/thread apply" are like
"unknown-is-operand", because "-" is a valid command.
- "compile file" and "compile code" are like "unknown-is-error".
These commands allow exercising all aspects of option processing
without having to pick some existing command. That should be more
stable going forward than relying on an existing user command,
since if we picked say "print", that command or its options could
change in future, and then we'd be left with having to pick some
other command or option to exercise some non-command-specific
option processing detail. Also, actual user commands have side
effects that we're not interested in when we're focusing on unit
testing the options machinery. BTW, a maintenance command is used
as a sort of unit test driver instead of actual "maint selftest"
unit tests, since we need to go all the way via gdb including
readline, for proper testing of TAB completion.
These maintenance commands support options of all the different
available kinds of commands (boolean, enum, flag, string, uinteger):
(gdb) maint test-options require-delimiter -[TAB]
-bool -enum -flag -string -uinteger -xx1 -xx2
(gdb) maint test-options require-delimiter -bool o[TAB]
off on
(gdb) maint test-options require-delimiter -enum [TAB]
xxx yyy zzz
(gdb) maint test-options require-delimiter -uinteger [TAB]
NUMBER unlimited
'-xx1' and '-xx2' are flag options too. They exist in order to
test ambiguous option names, like '-xx'.
Invoking the commands makes them print out the options parsed:
(gdb) maint test-options unknown-is-error -flag -enum yyy cmdarg
-flag 1 -xx1 0 -xx2 0 -bool 0 -enum yyy -uint 0 -zuint-unl 0 -- cmdarg
(gdb) maint test-options require-delimiter -flag -enum yyy cmdarg
-flag 0 -xx1 0 -xx2 0 -bool 0 -enum xxx -uint 0 -zuint-unl 0 -- -flag -enum yyy cmdarg
(gdb) maint test-options require-delimiter -flag -enum yyy cmdarg --
Unrecognized option at: cmdarg --
(gdb) maint test-options require-delimiter -flag -enum yyy -- cmdarg
-flag 1 -xx1 0 -xx2 0 -bool 0 -enum yyy -uint 0 -zuint-unl 0 -- cmdarg
The "maint show test-options-completion-result" command exists in
order to do something similar for completion:
(gdb) maint test-options unknown-is-error -flag -b 0 -enum yyy OPERAND[TAB]
(gdb) maint show test-options-completion-result
0 OPERAND
(gdb) maint test-options unknown-is-error -flag -b 0 -enum yyy[TAB]
(gdb) maint show test-options-completion-result
1
(gdb) maint test-options require-dash -unknown[TAB]
(gdb) maint show test-options-completion-result
1
Here, "1" means the completion function processed the whole input
line, and that the command shouldn't do anything with the arguments,
since there are no operands. While "0" indicates that there are
operands after options. The text after "0" is the operands.
This level of detail is particularly important because getting the
completion function's entry point to return back to the caller the
right pointer into the operand is quite tricky in several
scenarios. */
/* Enum values for the "maintenance test-options" commands. */
const char test_options_enum_values_xxx[] = "xxx";
const char test_options_enum_values_yyy[] = "yyy";
const char test_options_enum_values_zzz[] = "zzz";
static const char *const test_options_enum_values_choices[] =
{
test_options_enum_values_xxx,
test_options_enum_values_yyy,
test_options_enum_values_zzz,
NULL
};
/* Option data for the "maintenance test-options" commands. */
struct test_options_opts
{
bool flag_opt = false;
bool xx1_opt = false;
bool xx2_opt = false;
bool boolean_opt = false;
const char *enum_opt = test_options_enum_values_xxx;
unsigned int uint_opt = 0;
int zuint_unl_opt = 0;
std::string string_opt;
test_options_opts () = default;
DISABLE_COPY_AND_ASSIGN (test_options_opts);
/* Dump the options to FILE. ARGS is the remainder unprocessed
arguments. */
void dump (ui_file *file, const char *args) const
{
fprintf_unfiltered (file,
_("-flag %d -xx1 %d -xx2 %d -bool %d "
"-enum %s -uint %s -zuint-unl %s -string '%s' -- %s\n"),
flag_opt,
xx1_opt,
xx2_opt,
boolean_opt,
enum_opt,
(uint_opt == UINT_MAX
? "unlimited"
: pulongest (uint_opt)),
(zuint_unl_opt == -1
? "unlimited"
: plongest (zuint_unl_opt)),
string_opt.c_str (),
args);
}
};
/* Option definitions for the "maintenance test-options" commands. */
static const gdb::option::option_def test_options_option_defs[] = {
/* A flag option. */
gdb::option::flag_option_def<test_options_opts> {
"flag",
[] (test_options_opts *opts) { return &opts->flag_opt; },
N_("A flag option."),
},
/* A couple flags with similar names, for "ambiguous option names"
testing. */
gdb::option::flag_option_def<test_options_opts> {
"xx1",
[] (test_options_opts *opts) { return &opts->xx1_opt; },
N_("A flag option."),
},
gdb::option::flag_option_def<test_options_opts> {
"xx2",
[] (test_options_opts *opts) { return &opts->xx2_opt; },
N_("A flag option."),
},
/* A boolean option. */
gdb::option::boolean_option_def<test_options_opts> {
"bool",
[] (test_options_opts *opts) { return &opts->boolean_opt; },
nullptr, /* show_cmd_cb */
N_("A boolean option."),
},
/* An enum option. */
gdb::option::enum_option_def<test_options_opts> {
"enum",
test_options_enum_values_choices,
[] (test_options_opts *opts) { return &opts->enum_opt; },
nullptr, /* show_cmd_cb */
N_("An enum option."),
},
/* A uinteger option. */
gdb::option::uinteger_option_def<test_options_opts> {
"uinteger",
[] (test_options_opts *opts) { return &opts->uint_opt; },
nullptr, /* show_cmd_cb */
N_("A uinteger option."),
nullptr, /* show_doc */
N_("A help doc that spawns\nmultiple lines."),
},
/* A zuinteger_unlimited option. */
gdb::option::zuinteger_unlimited_option_def<test_options_opts> {
"zuinteger-unlimited",
[] (test_options_opts *opts) { return &opts->zuint_unl_opt; },
nullptr, /* show_cmd_cb */
N_("A zuinteger-unlimited option."),
nullptr, /* show_doc */
nullptr, /* help_doc */
},
/* A string option. */
gdb::option::string_option_def<test_options_opts> {
"string",
[] (test_options_opts *opts) { return &opts->string_opt; },
nullptr, /* show_cmd_cb */
N_("A string option."),
},
};
/* Create an option_def_group for the test_options_opts options, with
OPTS as context. */
static inline gdb::option::option_def_group
make_test_options_options_def_group (test_options_opts *opts)
{
return {{test_options_option_defs}, opts};
}
/* Implementation of the "maintenance test-options
require-delimiter/unknown-is-error/unknown-is-operand" commands.
Each of the commands maps to a different enum process_options_mode
enumerator. The test strategy is simply processing the options in
a number of scenarios, and printing back the parsed result. */
static void
maintenance_test_options_command_mode (const char *args,
gdb::option::process_options_mode mode)
{
test_options_opts opts;
gdb::option::process_options (&args, mode,
make_test_options_options_def_group (&opts));
if (args == nullptr)
args = "";
else
args = skip_spaces (args);
opts.dump (gdb_stdout, args);
}
/* Variable used by the "maintenance show
test-options-completion-result" command. This variable is stored
by the completer of the "maint test-options" subcommands.
If the completer returned false, this includes the text at the word
point after gdb::option::complete_options returns. If true, then
this includes a dump of the processed options. */
static std::string maintenance_test_options_command_completion_text;
/* The "maintenance show test-options-completion-result" command. */
static void
maintenance_show_test_options_completion_result (const char *args,
int from_tty)
{
puts_filtered (maintenance_test_options_command_completion_text.c_str ());
}
/* Save the completion result in the global variables read by the
"maintenance test-options require-delimiter" command. */
static void
save_completion_result (const test_options_opts &opts, bool res,
const char *text)
{
if (res)
{
string_file stream;
stream.puts ("1 ");
opts.dump (&stream, text);
maintenance_test_options_command_completion_text
= std::move (stream.string ());
}
else
{
maintenance_test_options_command_completion_text
= string_printf ("0 %s\n", text);
}
}
/* Implementation of completer for the "maintenance test-options
require-delimiter/unknown-is-error/unknown-is-operand" commands.
Each of the commands maps to a different enum process_options_mode
enumerator. */
static void
maintenance_test_options_completer_mode (completion_tracker &tracker,
const char *text,
gdb::option::process_options_mode mode)
{
test_options_opts opts;
try
{
bool res = (gdb::option::complete_options
(tracker, &text, mode,
make_test_options_options_def_group (&opts)));
save_completion_result (opts, res, text);
}
catch (const gdb_exception_error &ex)
{
save_completion_result (opts, true, text);
throw;
}
}
/* Implementation of the "maintenance test-options require-delimiter"
command. */
static void
maintenance_test_options_require_delimiter_command (const char *args,
int from_tty)
{
maintenance_test_options_command_mode
(args, gdb::option::PROCESS_OPTIONS_REQUIRE_DELIMITER);
}
/* Implementation of the "maintenance test-options
unknown-is-error" command. */
static void
maintenance_test_options_unknown_is_error_command (const char *args,
int from_tty)
{
maintenance_test_options_command_mode
(args, gdb::option::PROCESS_OPTIONS_UNKNOWN_IS_ERROR);
}
/* Implementation of the "maintenance test-options
unknown-is-operand" command. */
static void
maintenance_test_options_unknown_is_operand_command (const char *args,
int from_tty)
{
maintenance_test_options_command_mode
(args, gdb::option::PROCESS_OPTIONS_UNKNOWN_IS_OPERAND);
}
/* Completer for the "maintenance test-options require-delimiter"
command. */
static void
maintenance_test_options_require_delimiter_command_completer
(cmd_list_element *ignore, completion_tracker &tracker,
const char *text, const char *word)
{
maintenance_test_options_completer_mode
(tracker, text, gdb::option::PROCESS_OPTIONS_REQUIRE_DELIMITER);
}
/* Completer for the "maintenance test-options unknown-is-error"
command. */
static void
maintenance_test_options_unknown_is_error_command_completer
(cmd_list_element *ignore, completion_tracker &tracker,
const char *text, const char *word)
{
maintenance_test_options_completer_mode
(tracker, text, gdb::option::PROCESS_OPTIONS_UNKNOWN_IS_ERROR);
}
/* Completer for the "maintenance test-options unknown-is-operand"
command. */
static void
maintenance_test_options_unknown_is_operand_command_completer
(cmd_list_element *ignore, completion_tracker &tracker,
const char *text, const char *word)
{
maintenance_test_options_completer_mode
(tracker, text, gdb::option::PROCESS_OPTIONS_UNKNOWN_IS_OPERAND);
}
/* Command list for maint test-options. */
static cmd_list_element *maintenance_test_options_list;
void _initialize_maint_test_options ();
void
_initialize_maint_test_options ()
{
cmd_list_element *cmd;
add_basic_prefix_cmd ("test-options", no_class,
_("\
Generic command for testing the options infrastructure."),
&maintenance_test_options_list,
0, &maintenancelist);
const auto def_group = make_test_options_options_def_group (nullptr);
static const std::string help_require_delim_str
= gdb::option::build_help (_("\
Command used for testing options processing.\n\
Usage: maint test-options require-delimiter [[OPTION]... --] [OPERAND]...\n\
\n\
Options:\n\
%OPTIONS%\n\
\n\
If you specify any command option, you must use a double dash (\"--\")\n\
to mark the end of option processing."),
def_group);
static const std::string help_unknown_is_error_str
= gdb::option::build_help (_("\
Command used for testing options processing.\n\
Usage: maint test-options unknown-is-error [OPTION]... [OPERAND]...\n\
\n\
Options:\n\
%OPTIONS%"),
def_group);
static const std::string help_unknown_is_operand_str
= gdb::option::build_help (_("\
Command used for testing options processing.\n\
Usage: maint test-options unknown-is-operand [OPTION]... [OPERAND]...\n\
\n\
Options:\n\
%OPTIONS%"),
def_group);
cmd = add_cmd ("require-delimiter", class_maintenance,
maintenance_test_options_require_delimiter_command,
help_require_delim_str.c_str (),
&maintenance_test_options_list);
set_cmd_completer_handle_brkchars
(cmd, maintenance_test_options_require_delimiter_command_completer);
cmd = add_cmd ("unknown-is-error", class_maintenance,
maintenance_test_options_unknown_is_error_command,
help_unknown_is_error_str.c_str (),
&maintenance_test_options_list);
set_cmd_completer_handle_brkchars
(cmd, maintenance_test_options_unknown_is_error_command_completer);
cmd = add_cmd ("unknown-is-operand", class_maintenance,
maintenance_test_options_unknown_is_operand_command,
help_unknown_is_operand_str.c_str (),
&maintenance_test_options_list);
set_cmd_completer_handle_brkchars
(cmd, maintenance_test_options_unknown_is_operand_command_completer);
add_cmd ("test-options-completion-result", class_maintenance,
maintenance_show_test_options_completion_result,
_("\
Show maintenance test-options completion result.\n\
Shows the results of completing\n\
\"maint test-options require-delimiter\",\n\
\"maint test-options unknown-is-error\", or\n\
\"maint test-options unknown-is-operand\"."),
&maintenance_show_cmdlist);
}
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