config-file.hpp

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
#ifndef NFD_CORE_CONFIG_FILE_HPP
#define NFD_CORE_CONFIG_FILE_HPP

#include "common.hpp"

#include <boost/property_tree/ptree.hpp>

namespace nfd {

typedef boost::property_tree::ptree ConfigSection;

typedef boost::optional<const ConfigSection&> OptionalConfigSection;

typedef function<void(const ConfigSection& section,
                      bool isDryRun,
                      const std::string& filename)> ConfigSectionHandler;

typedef function<void(const std::string& filename,
                      const std::string& sectionName,
                      const ConfigSection& section,
                      bool isDryRun)> UnknownConfigSectionHandler;

class ConfigFile : noncopyable
{
public:
  class Error : public std::runtime_error
  {
  public:
    explicit
    Error(const std::string& what)
      : std::runtime_error(what)
    {
    }
  };

  explicit
  ConfigFile(UnknownConfigSectionHandler unknownSectionCallback = throwErrorOnUnknownSection);

public: // unknown section handlers
  static void
  throwErrorOnUnknownSection(const std::string& filename,
                             const std::string& sectionName,
                             const ConfigSection& section,
                             bool isDryRun);

  static void
  ignoreUnknownSection(const std::string& filename,
                       const std::string& sectionName,
                       const ConfigSection& section,
                       bool isDryRun);

public: // parse helpers
  static bool
  parseYesNo(const ConfigSection& node, const std::string& key, const std::string& sectionName);

  static bool
  parseYesNo(const ConfigSection::value_type& option, const std::string& sectionName)
  {
    return parseYesNo(option.second, option.first, sectionName);
  }

  template<typename T>
  static T
  parseNumber(const ConfigSection& node, const std::string& key, const std::string& sectionName)
  {
    static_assert(std::is_arithmetic<T>::value, "T must be an arithmetic type");

    boost::optional<T> value = node.get_value_optional<T>();
    if (value) {
      return *value;
    }
    BOOST_THROW_EXCEPTION(Error("Invalid value \"" + node.get_value<std::string>() +
                                "\" for option \"" + key + "\" in \"" + sectionName + "\" section"));
  }

  template <typename T>
  static T
  parseNumber(const ConfigSection::value_type& option, const std::string& sectionName)
  {
    return parseNumber<T>(option.second, option.first, sectionName);
  }

public: // setup and parsing
  void
  addSectionHandler(const std::string& sectionName,
                    ConfigSectionHandler subscriber);

  void
  parse(const std::string& filename, bool isDryRun);

  void
  parse(const std::string& input, bool isDryRun, const std::string& filename);

  void
  parse(std::istream& input, bool isDryRun, const std::string& filename);

  void
  parse(const ConfigSection& config, bool isDryRun, const std::string& filename);

private:
  void
  process(bool isDryRun, const std::string& filename) const;

private:
  UnknownConfigSectionHandler m_unknownSectionCallback;
  std::map<std::string, ConfigSectionHandler> m_subscriptions;
  ConfigSection m_global;
};

} // namespace nfd

#endif // NFD_CORE_CONFIG_FILE_HPP