lib/options.h

/*
Copyright 2013-present Barefoot Networks, Inc.
 
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.
*/
 
#ifndef LIB_OPTIONS_H_
#define LIB_OPTIONS_H_
 
#include <functional>
#include <iostream>
#include <ostream>
#include <stdexcept>
#include <string>
#include <vector>
 
#include "cstring.h"
#include "error.h"
#include "map.h"
 
namespace Util {
 
// Command-line options processing
class Options {
 public:
    enum OptionFlags {
        Default = 0,
 
        Hide = 1 << 0,
 
        OptionalArgument = 1 << 1,
    };
 
    // return true if processing is successful
    using OptionProcessor = std::function<bool(const char *)>;
 
 protected:
    struct Option {
        cstring option;
        const char *argName;  // nullptr if argument is not required
        const char *description;
        OptionProcessor processor;
        OptionFlags flags;
    };
    const char *binaryName;
    cstring message;
    // Build date and compile command required in couple runtime files
    cstring compileCommand;
    cstring buildDate;
    std::ostream *outStream = &std::cerr;
 
    std::map<cstring, const Option *> options;
    std::vector<cstring> optionOrder;
    std::vector<const char *> additionalUsage;
    std::vector<const char *> remainingOptions;  // produced as output
    // if true unknown options are collected in remainingOptions
    bool collectUnknownOptions = false;
 
    void setOutStream(std::ostream *out) { outStream = out; }
    void registerUsage(const char *msg) { additionalUsage.push_back(msg); }
    void registerOption(const char *option,         // option to register, e.g., -c or --version
                        const char *argName,        // name of option argument;
                                                    // nullptr if no argument expected
                        OptionProcessor processor,  // function to execute when option matches
                        const char *description,    // option help message
                        OptionFlags flags = OptionFlags::Default);  // additional flags
 
    explicit Options(std::string_view message)
        : binaryName(nullptr), message(message), compileCommand("") {}
 
    [[nodiscard]] virtual bool validateOptions() const;
 
 public:
    virtual std::vector<const char *> *process(int argc, char *const argv[]);
 
    [[nodiscard]] virtual const char *getIncludePath() const = 0;
    cstring getCompileCommand() { return compileCommand; }
    cstring getBuildDate() { return buildDate; }
    cstring getBinaryName() { return cstring(binaryName); }
    virtual void usage();
};
 
}  // namespace Util
 
#endif /* LIB_OPTIONS_H_ */