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https://github.com/SerenityOS/serenity
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a9df60ff1c
On argument swapping to put positional ones toward the end, m_arg_index was pointing at "last arg index" + "skipped args" + "consumed args" and thus was pointing ahead of the skipped ones. m_arg_index now points after the current parsed option arguments.
290 lines
9.5 KiB
C++
290 lines
9.5 KiB
C++
/*
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* Copyright (c) 2023, Ali Mohammad Pur <mpfard@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/OptionParser.h>
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namespace AK {
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void OptionParser::reset_state()
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{
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m_arg_index = 0;
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m_consumed_args = 0;
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m_index_into_multioption_argument = 0;
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m_stop_on_first_non_option = false;
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}
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OptionParser::GetOptResult OptionParser::getopt(Span<StringView> args, StringView short_options, Span<Option const> long_options, Optional<int&> out_long_option_index)
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{
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m_args = args;
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m_short_options = short_options;
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m_long_options = long_options;
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m_out_long_option_index = out_long_option_index;
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// In the following case:
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// $ foo bar -o baz
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// we want to parse the option (-o baz) first, and leave the argument (bar)
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// in argv after we return -1 when invoked the second time. So we reorder
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// argv to put options first and positional arguments next. To turn this
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// behavior off, start the short options spec with a "+". This is a GNU
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// extension that we support.
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m_stop_on_first_non_option = short_options.starts_with('+');
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bool should_reorder_argv = !m_stop_on_first_non_option;
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int res = -1;
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bool found_an_option = find_next_option();
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auto arg = current_arg();
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if (!found_an_option) {
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res = -1;
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if (arg == "--")
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m_consumed_args = 1;
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else
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m_consumed_args = 0;
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} else {
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// Alright, so we have an option on our hands!
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bool is_long_option = arg.starts_with("--"sv);
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if (is_long_option)
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res = handle_long_option();
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else
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res = handle_short_option();
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// If we encountered an error, return immediately.
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if (res == '?') {
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return {
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.result = '?',
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.optopt_value = m_optopt_value,
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.optarg_value = m_optarg_value,
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.consumed_args = 0,
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};
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}
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}
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if (should_reorder_argv)
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shift_argv();
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m_arg_index += m_consumed_args;
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return {
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.result = res,
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.optopt_value = m_optopt_value,
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.optarg_value = m_optarg_value,
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.consumed_args = m_consumed_args,
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};
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}
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Optional<OptionParser::ArgumentRequirement> OptionParser::lookup_short_option_requirement(char option) const
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{
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Vector<StringView> parts = m_short_options.split_view(option, SplitBehavior::KeepEmpty);
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VERIFY(parts.size() <= 2);
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if (parts.size() < 2) {
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// Haven't found the option in the spec.
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return {};
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}
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if (parts[1].starts_with("::"sv)) {
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// If an option is followed by two colons, it optionally accepts an
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// argument.
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return ArgumentRequirement::HasOptionalArgument;
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}
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if (parts[1].starts_with(':')) {
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// If it's followed by one colon, it requires an argument.
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return ArgumentRequirement::HasRequiredArgument;
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}
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// Otherwise, it doesn't accept arguments.
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return ArgumentRequirement::NoArgument;
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}
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int OptionParser::handle_short_option()
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{
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StringView arg = current_arg();
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VERIFY(arg.starts_with('-'));
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if (m_index_into_multioption_argument == 0) {
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// Just starting to parse this argument, skip the "-".
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m_index_into_multioption_argument = 1;
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}
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char option = arg[m_index_into_multioption_argument];
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m_index_into_multioption_argument++;
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auto maybe_requirement = lookup_short_option_requirement(option);
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if (!maybe_requirement.has_value()) {
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m_optopt_value = option;
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reportln("Unrecognized option \x1b[1m-{:c}\x1b[22m", option);
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return '?';
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}
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auto argument_requirement = *maybe_requirement;
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// Let's see if we're at the end of this argument already.
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if (m_index_into_multioption_argument < arg.length()) {
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// This not yet the end.
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if (argument_requirement == ArgumentRequirement::NoArgument) {
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m_optarg_value = {};
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m_consumed_args = 0;
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} else {
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// Treat the rest of the argument as the value, the "-ovalue"
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// syntax.
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m_optarg_value = m_args[m_arg_index].substring_view(m_index_into_multioption_argument);
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// Next time, process the next argument.
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m_index_into_multioption_argument = 0;
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m_consumed_args = 1;
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}
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} else {
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m_index_into_multioption_argument = 0;
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if (argument_requirement != ArgumentRequirement::HasRequiredArgument) {
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m_optarg_value = StringView();
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m_consumed_args = 1;
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} else if (m_arg_index + 1 < m_args.size()) {
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// Treat the next argument as a value, the "-o value" syntax.
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m_optarg_value = m_args[m_arg_index + 1];
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m_consumed_args = 2;
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} else {
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reportln("Missing value for option \x1b[1m-{:c}\x1b[22m", option);
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return '?';
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}
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}
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return option;
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}
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Optional<OptionParser::Option const&> OptionParser::lookup_long_option(StringView arg) const
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{
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for (size_t index = 0; index < m_long_options.size(); index++) {
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auto& option = m_long_options[index];
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if (!arg.starts_with(option.name))
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continue;
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// It would be better to not write out the index at all unless we're
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// sure we've found the right option, but whatever.
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if (m_out_long_option_index.has_value())
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*m_out_long_option_index = index;
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// Can either be "--option" or "--option=value".
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if (arg.length() == option.name.length()) {
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m_optarg_value = {};
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return option;
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}
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if (arg[option.name.length()] == '=') {
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m_optarg_value = arg.substring_view(option.name.length() + 1);
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return option;
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}
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}
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return {};
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}
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int OptionParser::handle_long_option()
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{
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VERIFY(current_arg().starts_with("--"sv));
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// We cannot set optopt to anything sensible for long options, so set it to 0.
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m_optopt_value = 0;
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auto option = lookup_long_option(m_args[m_arg_index].substring_view(2));
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if (!option.has_value()) {
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reportln("Unrecognized option \x1b[1m{}\x1b[22m", m_args[m_arg_index]);
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return '?';
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}
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// lookup_long_option() will also set an override for optarg if the value of the option is
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// specified using "--option=value" syntax.
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// Figure out whether this option needs and/or has a value (also called "an
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// argument", but let's not call it that to distinguish it from argv
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// elements).
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switch (option->requirement) {
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case ArgumentRequirement::NoArgument:
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if (m_optarg_value.has_value()) {
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reportln("Option \x1b[1m--{}\x1b[22m doesn't accept an argument", option->name);
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return '?';
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}
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m_consumed_args = 1;
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break;
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case ArgumentRequirement::HasOptionalArgument:
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m_consumed_args = 1;
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break;
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case ArgumentRequirement::HasRequiredArgument:
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if (m_optarg_value.has_value()) {
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// Value specified using "--option=value" syntax.
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m_consumed_args = 1;
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} else if (m_arg_index + 1 < m_args.size()) {
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// Treat the next argument as a value in "--option value" syntax.
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m_optarg_value = m_args[m_arg_index + 1];
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m_consumed_args = 2;
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} else {
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reportln("Missing value for option \x1b[1m--{}\x1b[22m", option->name);
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return '?';
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}
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break;
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default:
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VERIFY_NOT_REACHED();
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}
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// Now that we've figured the value out, see about reporting this option to
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// our caller.
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if (option->flag != nullptr) {
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*option->flag = option->val;
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return 0;
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}
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return option->val;
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}
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void OptionParser::shift_argv()
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{
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// We've just parsed an option (which perhaps has a value).
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// Put the option (along with its value, if any) in front of other arguments.
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if (m_consumed_args == 0 && m_skipped_arguments == 0) {
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// Nothing to do!
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return;
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}
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// x -a b c d
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// ---- consumed
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// ->
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// -a b x c d
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StringView buffer[2]; // We consume at most 2 arguments in one call.
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Span<StringView> buffer_bytes { buffer, array_size(buffer) };
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m_args.slice(m_arg_index, m_consumed_args).copy_to(buffer_bytes);
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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));
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buffer_bytes.slice(0, m_consumed_args).copy_to(m_args.slice(m_arg_index - m_skipped_arguments, m_consumed_args));
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// m_arg_index took into account m_skipped_arguments (both are inc in find_next_option)
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// so now we have to make m_arg_index point to the beginning of skipped arguments
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m_arg_index -= m_skipped_arguments;
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// and let's forget about skipped arguments
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m_skipped_arguments = 0;
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}
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bool OptionParser::find_next_option()
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{
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for (m_skipped_arguments = 0; m_arg_index < m_args.size(); m_skipped_arguments++, m_arg_index++) {
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StringView arg = current_arg();
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// Anything that doesn't start with a "-" is not an option.
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// As a special case, a single "-" is not an option either.
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// (It's typically used by programs to refer to stdin).
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if (!arg.starts_with('-') || arg == "-") {
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if (m_stop_on_first_non_option)
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return false;
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continue;
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}
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// As another special case, a "--" is not an option either, and we stop
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// looking for further options if we encounter it.
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if (arg == "--")
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return false;
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// Otherwise, we have found an option!
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return true;
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}
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// Reached the end and still found no options.
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return false;
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}
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}
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