/*
* Copyright (c) 2023, Ali Mohammad Pur <mpfard@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/OptionParser.h>
namespace AK {
void OptionParser::reset_state()
{
m_arg_index = 0;
m_consumed_args = 0;
m_index_into_multioption_argument = 0;
m_stop_on_first_non_option = false;
}
OptionParser::GetOptResult OptionParser::getopt(Span<StringView> args, StringView short_options, Span<Option const> long_options, Optional<int&> out_long_option_index)
{
m_args = args;
m_short_options = short_options;
m_long_options = long_options;
m_out_long_option_index = out_long_option_index;
// In the following case:
// $ foo bar -o baz
// we want to parse the option (-o baz) first, and leave the argument (bar)
// in argv after we return -1 when invoked the second time. So we reorder
// argv to put options first and positional arguments next. To turn this
// behavior off, start the short options spec with a "+". This is a GNU
// extension that we support.
m_stop_on_first_non_option = short_options.starts_with('+');
bool should_reorder_argv = !m_stop_on_first_non_option;
int res = -1;
bool found_an_option = find_next_option();
auto arg = current_arg();
if (!found_an_option) {
res = -1;
if (arg == "--")
m_consumed_args = 1;
else
m_consumed_args = 0;
} else {
// Alright, so we have an option on our hands!
bool is_long_option = arg.starts_with("--"sv);
if (is_long_option)
res = handle_long_option();
else
res = handle_short_option();
// If we encountered an error, return immediately.
if (res == '?') {
return {
.result = '?',
.optopt_value = m_optopt_value,
.optarg_value = m_optarg_value,
.consumed_args = 0,
};
}
}
if (should_reorder_argv)
shift_argv();
m_arg_index += m_consumed_args;
return {
.result = res,
.optopt_value = m_optopt_value,
.optarg_value = m_optarg_value,
.consumed_args = m_consumed_args,
};
}
Optional<OptionParser::ArgumentRequirement> OptionParser::lookup_short_option_requirement(char option) const
{
Vector<StringView> parts = m_short_options.split_view(option, SplitBehavior::KeepEmpty);
VERIFY(parts.size() <= 2);
if (parts.size() < 2) {
// Haven't found the option in the spec.
return {};
}
if (parts[1].starts_with("::"sv)) {
// If an option is followed by two colons, it optionally accepts an
// argument.
return ArgumentRequirement::HasOptionalArgument;
}
if (parts[1].starts_with(':')) {
// If it's followed by one colon, it requires an argument.
return ArgumentRequirement::HasRequiredArgument;
}
// Otherwise, it doesn't accept arguments.
return ArgumentRequirement::NoArgument;
}
int OptionParser::handle_short_option()
{
StringView arg = current_arg();
VERIFY(arg.starts_with('-'));
if (m_index_into_multioption_argument == 0) {
// Just starting to parse this argument, skip the "-".
m_index_into_multioption_argument = 1;
}
char option = arg[m_index_into_multioption_argument];
m_index_into_multioption_argument++;
auto maybe_requirement = lookup_short_option_requirement(option);
if (!maybe_requirement.has_value()) {
m_optopt_value = option;
reportln("Unrecognized option \x1b[1m-{:c}\x1b[22m", option);
return '?';
}
auto argument_requirement = *maybe_requirement;
// Let's see if we're at the end of this argument already.
if (m_index_into_multioption_argument < arg.length()) {
// This not yet the end.
if (argument_requirement == ArgumentRequirement::NoArgument) {
m_optarg_value = {};
m_consumed_args = 0;
} else {
// Treat the rest of the argument as the value, the "-ovalue"
// syntax.
m_optarg_value = m_args[m_arg_index].substring_view(m_index_into_multioption_argument);
// Next time, process the next argument.
m_index_into_multioption_argument = 0;
m_consumed_args = 1;
}
} else {
m_index_into_multioption_argument = 0;
if (argument_requirement != ArgumentRequirement::HasRequiredArgument) {
m_optarg_value = StringView();
m_consumed_args = 1;
} else if (m_arg_index + 1 < m_args.size()) {
// Treat the next argument as a value, the "-o value" syntax.
m_optarg_value = m_args[m_arg_index + 1];
m_consumed_args = 2;
} else {
reportln("Missing value for option \x1b[1m-{:c}\x1b[22m", option);
return '?';
}
}
return option;
}
Optional<OptionParser::Option const&> OptionParser::lookup_long_option(StringView arg) const
{
for (size_t index = 0; index < m_long_options.size(); index++) {
auto& option = m_long_options[index];
if (!arg.starts_with(option.name))
continue;
// It would be better to not write out the index at all unless we're
// sure we've found the right option, but whatever.
if (m_out_long_option_index.has_value())
*m_out_long_option_index = index;
// Can either be "--option" or "--option=value".
if (arg.length() == option.name.length()) {
m_optarg_value = {};
return option;
}
if (arg[option.name.length()] == '=') {
m_optarg_value = arg.substring_view(option.name.length() + 1);
return option;
}
}
return {};
}
int OptionParser::handle_long_option()
{
VERIFY(current_arg().starts_with("--"sv));
// We cannot set optopt to anything sensible for long options, so set it to 0.
m_optopt_value = 0;
auto option = lookup_long_option(m_args[m_arg_index].substring_view(2));
if (!option.has_value()) {
reportln("Unrecognized option \x1b[1m{}\x1b[22m", m_args[m_arg_index]);
return '?';
}
// lookup_long_option() will also set an override for optarg if the value of the option is
// specified using "--option=value" syntax.
// Figure out whether this option needs and/or has a value (also called "an
// argument", but let's not call it that to distinguish it from argv
// elements).
switch (option->requirement) {
case ArgumentRequirement::NoArgument:
if (m_optarg_value.has_value()) {
reportln("Option \x1b[1m--{}\x1b[22m doesn't accept an argument", option->name);
return '?';
}
m_consumed_args = 1;
break;
case ArgumentRequirement::HasOptionalArgument:
m_consumed_args = 1;
break;
case ArgumentRequirement::HasRequiredArgument:
if (m_optarg_value.has_value()) {
// Value specified using "--option=value" syntax.
m_consumed_args = 1;
} else if (m_arg_index + 1 < m_args.size()) {
// Treat the next argument as a value in "--option value" syntax.
m_optarg_value = m_args[m_arg_index + 1];
m_consumed_args = 2;
} else {
reportln("Missing value for option \x1b[1m--{}\x1b[22m", option->name);
return '?';
}
break;
default:
VERIFY_NOT_REACHED();
}
// Now that we've figured the value out, see about reporting this option to
// our caller.
if (option->flag != nullptr) {
*option->flag = option->val;
return 0;
}
return option->val;
}
void OptionParser::shift_argv()
{
// We've just parsed an option (which perhaps has a value).
// Put the option (along with its value, if any) in front of other arguments.
if (m_consumed_args == 0 && m_skipped_arguments == 0) {
// Nothing to do!
return;
}
// x -a b c d
// ---- consumed
// ->
// -a b x c d
StringView buffer[2]; // We consume at most 2 arguments in one call.
Span<StringView> buffer_bytes { buffer, array_size(buffer) };
m_args.slice(m_arg_index, m_consumed_args).copy_to(buffer_bytes);
m_args.slice(m_arg_index - m_skipped_arguments, m_skipped_arguments).copy_to(m_args.slice(m_arg_index + m_consumed_args - m_skipped_arguments));
buffer_bytes.slice(0, m_consumed_args).copy_to(m_args.slice(m_arg_index - m_skipped_arguments, m_consumed_args));
// m_arg_index took into account m_skipped_arguments (both are inc in find_next_option)
// so now we have to make m_arg_index point to the beginning of skipped arguments
m_arg_index -= m_skipped_arguments;
// and let's forget about skipped arguments
m_skipped_arguments = 0;
}
bool OptionParser::find_next_option()
{
for (m_skipped_arguments = 0; m_arg_index < m_args.size(); m_skipped_arguments++, m_arg_index++) {
StringView arg = current_arg();
// Anything that doesn't start with a "-" is not an option.
// As a special case, a single "-" is not an option either.
// (It's typically used by programs to refer to stdin).
if (!arg.starts_with('-') || arg == "-") {
if (m_stop_on_first_non_option)
return false;
continue;
}
// As another special case, a "--" is not an option either, and we stop
// looking for further options if we encounter it.
if (arg == "--")
return false;
// Otherwise, we have found an option!
return true;
}
// Reached the end and still found no options.
return false;
}
}
