Options.cpp

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// The Reactive C++ Toolbox.
// Copyright (C) 2013-2019 Swirly Cloud Limited
// Copyright (C) 2021 Reactive Markets Limited
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
 
#include "Options.hpp"
 
#include <toolbox/util/Argv.hpp>
#include <toolbox/util/Variant.hpp>
 
#include <iostream>
 
namespace toolbox {
inline namespace util {
using namespace std;
 
Options::Options(string description)
: description_{std::move(description)}
{
}
 
bool Options::operator[](const string& long_opt) const noexcept
{
    return opts_.count(long_opt);
}
 
bool Options::operator[](char short_opt) const noexcept
{
    return opts_.count(std::string_view{&short_opt, 1});
}
 
void Options::parse(int argc, const char* const argv[])
{
    size_t positional_idx{0};
    ArgvLexer lex{argc - 1, argv + 1};
    while (!lex.empty()) {
        const auto opt = lex.opt();
 
        bool positional{false};
        OptsMap::iterator it{opts_.end()};
 
        if (!opt.empty()) {
            it = opts_.find(opt);
        } else {
            if (positional_idx >= positional_.size()) {
                throw runtime_error{"unexpected argument: " + string{lex.arg()}};
            }
            positional = true;
        }
 
        if (!positional && it == opts_.end()) {
            throw runtime_error{"unknown option: " + string{opt}};
        }
 
        auto& data = positional ? positional_[positional_idx++] : it->second->data;
 
        visit(overloaded{[&](const Help& /*arg*/) {
                             lex.pop_switch();
                             cout << *this << "\n";
                             exit(0);
                         },
                         [&](Switch& arg) {
                             lex.pop_switch();
                             arg.run();
                         },
                         [&](Value& arg) {
                             const auto val = lex.pop_value();
                             if (arg.set_ && !arg.multitoken_) {
                                 throw runtime_error{"duplicate option: " + string{opt}};
                             }
                             arg.run(val);
                         },
                         [&](const NoOp&) { lex.pop(); }},
              data);
    }
 
    // Ensure all required parameters have been set.
    // FIXME: but we're not checking required positional arguments?
    for (const auto& data : opts_) {
        visit(overloaded{[](const auto& /*def*/) {},
                         [&](const Value& arg) {
                             if (arg.presence() == Value::Required && !arg.set()) {
                                 throw runtime_error{"missing required option: "
                                                     + data.second->opt()};
                             }
                         }},
              data.second->data);
    }
    for (const auto& data : positional_) {
        visit(overloaded{[](const auto& /*def*/) {},
                         [&](const Value& arg) {
                             if (arg.presence() == Value::Required && !arg.set()) {
                                 throw runtime_error{"missing positional argument"};
                             }
                         }},
              data);
    }
}
 
} // namespace util
} // namespace toolbox