core: move nfd-specific files to daemon/

Refs: #4922
Change-Id: I2243dbb87c63f9cbaf7d7051d7a0d4bca2f9fdb5
diff --git a/daemon/common/config-file.hpp b/daemon/common/config-file.hpp
new file mode 100644
index 0000000..20e778b
--- /dev/null
+++ b/daemon/common/config-file.hpp
@@ -0,0 +1,180 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/*
+ * Copyright (c) 2014-2019,  Regents of the University of California,
+ *                           Arizona Board of Regents,
+ *                           Colorado State University,
+ *                           University Pierre & Marie Curie, Sorbonne University,
+ *                           Washington University in St. Louis,
+ *                           Beijing Institute of Technology,
+ *                           The University of Memphis.
+ *
+ * This file is part of NFD (Named Data Networking Forwarding Daemon).
+ * See AUTHORS.md for complete list of NFD authors and contributors.
+ *
+ * NFD is free software: you can redistribute it and/or modify it under the terms
+ * of the GNU General Public License as published by the Free Software Foundation,
+ * either version 3 of the License, or (at your option) any later version.
+ *
+ * NFD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+ * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * NFD, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef NFD_DAEMON_COMMON_CONFIG_FILE_HPP
+#define NFD_DAEMON_COMMON_CONFIG_FILE_HPP
+
+#include "core/common.hpp"
+
+#include <boost/property_tree/ptree.hpp>
+
+namespace nfd {
+
+/** \brief a config file section
+ */
+using ConfigSection = boost::property_tree::ptree;
+
+/** \brief an optional config file section
+ */
+using OptionalConfigSection = boost::optional<const ConfigSection&>;
+
+/** \brief callback to process a config file section
+ */
+using ConfigSectionHandler = std::function<void(const ConfigSection& section, bool isDryRun,
+                                                const std::string& filename)>;
+
+/** \brief callback to process a config file section without a \p ConfigSectionHandler
+ */
+using UnknownConfigSectionHandler = std::function<void(const std::string& filename,
+                                                       const std::string& sectionName,
+                                                       const ConfigSection& section,
+                                                       bool isDryRun)>;
+
+/** \brief configuration file parsing utility
+ */
+class ConfigFile : noncopyable
+{
+public:
+  class Error : public std::runtime_error
+  {
+  public:
+    using std::runtime_error::runtime_error;
+  };
+
+  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
+  /** \brief parse a config option that can be either "yes" or "no"
+   *  \retval true "yes"
+   *  \retval false "no"
+   *  \throw Error the value is neither "yes" nor "no"
+   */
+  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);
+  }
+
+  /**
+   * \brief parse a numeric (integral or floating point) config option
+   * \tparam T an arithmetic type
+   *
+   * \return the numeric value of the parsed option
+   * \throw Error the value cannot be converted to the specified type
+   */
+  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;
+    }
+    NDN_THROW(Error("Invalid value '" + node.get_value<std::string>() +
+                    "' for option '" + key + "' in section '" + sectionName + "'"));
+  }
+
+  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
+  /// \brief setup notification of configuration file sections
+  void
+  addSectionHandler(const std::string& sectionName,
+                    ConfigSectionHandler subscriber);
+
+  /**
+   * \param filename file to parse
+   * \param isDryRun true if performing a dry run of configuration, false otherwise
+   * \throws ConfigFile::Error if file not found
+   * \throws ConfigFile::Error if parse error
+   */
+  void
+  parse(const std::string& filename, bool isDryRun);
+
+  /**
+   * \param input configuration (as a string) to parse
+   * \param isDryRun true if performing a dry run of configuration, false otherwise
+   * \param filename logical filename of the config file, can appear in error messages
+   * \throws ConfigFile::Error if file not found
+   * \throws ConfigFile::Error if parse error
+   */
+  void
+  parse(const std::string& input, bool isDryRun, const std::string& filename);
+
+  /**
+   * \param input stream to parse
+   * \param isDryRun true if performing a dry run of configuration, false otherwise
+   * \param filename logical filename of the config file, can appear in error messages
+   * \throws ConfigFile::Error if parse error
+   */
+  void
+  parse(std::istream& input, bool isDryRun, const std::string& filename);
+
+  /**
+   * \param config ConfigSection that needs to be processed
+   * \param isDryRun true if performing a dry run of configuration, false otherwise
+   * \param filename logical filename of the config file, can appear in error messages
+   * \throws ConfigFile::Error if parse error
+   */
+  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_DAEMON_COMMON_CONFIG_FILE_HPP