text: // Copyright 2012 The Kyua Authors.
  // All rights reserved.
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  //
  // * Redistributions of source code must retain the above copyright
  //   notice, this list of conditions and the following disclaimer.
  // * Redistributions in binary form must reproduce the above copyright
  //   notice, this list of conditions and the following disclaimer in the
  //   documentation and/or other materials provided with the distribution.
  // * Neither the name of Google Inc. nor the names of its contributors
  //   may be used to endorse or promote products derived from this software
  //   without specific prior written permission.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  
  #include "model/metadata.hpp"
  
  #include <memory>
  
  #include "model/exceptions.hpp"
  #include "model/types.hpp"
  #include "utils/config/exceptions.hpp"
  #include "utils/config/nodes.ipp"
  #include "utils/config/tree.ipp"
  #include "utils/datetime.hpp"
  #include "utils/defs.hpp"
  #include "utils/format/macros.hpp"
  #include "utils/fs/exceptions.hpp"
  #include "utils/fs/path.hpp"
  #include "utils/noncopyable.hpp"
  #include "utils/optional.ipp"
  #include "utils/sanity.hpp"
  #include "utils/text/exceptions.hpp"
  #include "utils/text/operations.hpp"
  #include "utils/units.hpp"
  
  namespace config = utils::config;
  namespace datetime = utils::datetime;
  namespace fs = utils::fs;
  namespace text = utils::text;
  namespace units = utils::units;
  
  using utils::optional;
  
  
  namespace {
  
  
  /// Global instance of defaults.
  ///
  /// This exists so that the getters in metadata can return references instead
  /// of object copies.  Use get_defaults() to query.
  static optional< config::tree > defaults;
  
  
  /// A leaf node that holds a bytes quantity.
  class bytes_node : public config::native_leaf_node< units::bytes > {
  public:
      /// Copies the node.
      ///
      /// \return A dynamically-allocated node.
      virtual base_node*
      deep_copy(void) const
      {
          std::auto_ptr< bytes_node > new_node(new bytes_node());
          new_node->_value = _value;
          return new_node.release();
      }
  
      /// Pushes the node's value onto the Lua stack.
      void
      push_lua(lutok::state& /* state */) const
      {
          UNREACHABLE;
      }
  
      /// Sets the value of the node from an entry in the Lua stack.
      void
      set_lua(lutok::state& /* state */, const int /* index */)
      {
          UNREACHABLE;
      }
  };
  
  
  /// A leaf node that holds a time delta.
  class delta_node : public config::typed_leaf_node< datetime::delta > {
  public:
      /// Copies the node.
      ///
      /// \return A dynamically-allocated node.
      virtual base_node*
      deep_copy(void) const
      {
          std::auto_ptr< delta_node > new_node(new delta_node());
          new_node->_value = _value;
          return new_node.release();
      }
  
      /// Sets the value of the node from a raw string representation.
      ///
      /// \param raw_value The value to set the node to.
      ///
      /// \throw value_error If the value is invalid.
      void
      set_string(const std::string& raw_value)
      {
          unsigned int seconds;
          try {
              seconds = text::to_type< unsigned int >(raw_value);
          } catch (const text::error& e) {
              throw config::value_error(F("Invalid time delta %s") % raw_value);
          }
          set(datetime::delta(seconds, 0));
      }
  
      /// Converts the contents of the node to a string.
      ///
      /// \pre The node must have a value.
      ///
      /// \return A string representation of the value held by the node.
      std::string
      to_string(void) const
      {
          return F("%s") % value().seconds;
      }
  
      /// Pushes the node's value onto the Lua stack.
      void
      push_lua(lutok::state& /* state */) const
      {
          UNREACHABLE;
      }
  
      /// Sets the value of the node from an entry in the Lua stack.
      void
      set_lua(lutok::state& /* state */, const int /* index */)
      {
          UNREACHABLE;
      }
  };
  
  
  /// A leaf node that holds a "required user" property.
  ///
  /// This node is just a string, but it provides validation of the only allowed
  /// values.
  class user_node : public config::string_node {
      /// Copies the node.
      ///
      /// \return A dynamically-allocated node.
      virtual base_node*
      deep_copy(void) const
      {
          std::auto_ptr< user_node > new_node(new user_node());
          new_node->_value = _value;
          return new_node.release();
      }
  
      /// Checks a given user textual representation for validity.
      ///
      /// \param user The value to validate.
      ///
      /// \throw config::value_error If the value is not valid.
      void
      validate(const value_type& user) const
      {
          if (!user.empty() && user != "root" && user != "unprivileged")
              throw config::value_error("Invalid required user value");
      }
  };
  
  
  /// A leaf node that holds a set of paths.
  ///
  /// This node type is used to represent the value of the required files and
  /// required programs, for example, and these do not allow relative paths.  We
  /// check this here.
  class paths_set_node : public config::base_set_node< fs::path > {
      /// Copies the node.
      ///
      /// \return A dynamically-allocated node.
      virtual base_node*
      deep_copy(void) const
      {
          std::auto_ptr< paths_set_node > new_node(new paths_set_node());
          new_node->_value = _value;
          return new_node.release();
      }
  
      /// Converts a single path to the native type.
      ///
      /// \param raw_value The value to parse.
      ///
      /// \return The parsed value.
      ///
      /// \throw config::value_error If the value is invalid.
      fs::path
      parse_one(const std::string& raw_value) const
      {
          try {
              return fs::path(raw_value);
          } catch (const fs::error& e) {
              throw config::value_error(e.what());
          }
      }
  
      /// Checks a collection of paths for validity.
      ///
      /// \param paths The value to validate.
      ///
      /// \throw config::value_error If the value is not valid.
      void
      validate(const value_type& paths) const
      {
          for (value_type::const_iterator iter = paths.begin();
               iter != paths.end(); ++iter) {
              const fs::path& path = *iter;
              if (!path.is_absolute() && path.ncomponents() > 1)
                  throw config::value_error(F("Relative path '%s' not allowed") %
                                            *iter);
          }
      }
  };
  
  
  /// Initializes a tree to hold test case requirements.
  ///
  /// \param [in,out] tree The tree to initialize.
  static void
  init_tree(config::tree& tree)
  {
      tree.define< config::strings_set_node >("allowed_architectures");
      tree.define< config::strings_set_node >("allowed_platforms");
      tree.define_dynamic("custom");
      tree.define< config::string_node >("description");
      tree.define< config::bool_node >("has_cleanup");
      tree.define< config::bool_node >("is_exclusive");
      tree.define< config::strings_set_node >("required_configs");
      tree.define< bytes_node >("required_disk_space");
      tree.define< paths_set_node >("required_files");
      tree.define< bytes_node >("required_memory");
      tree.define< paths_set_node >("required_programs");
      tree.define< user_node >("required_user");
      tree.define< delta_node >("timeout");
  }
  
  
  /// Sets default values on a tree object.
  ///
  /// \param [in,out] tree The tree to configure.
  static void
  set_defaults(config::tree& tree)
  {
      tree.set< config::strings_set_node >("allowed_architectures",
                                           model::strings_set());
      tree.set< config::strings_set_node >("allowed_platforms",
                                           model::strings_set());
      tree.set< config::string_node >("description", "");
      tree.set< config::bool_node >("has_cleanup", false);
      tree.set< config::bool_node >("is_exclusive", false);
      tree.set< config::strings_set_node >("required_configs",
                                           model::strings_set());
      tree.set< bytes_node >("required_disk_space", units::bytes(0));
      tree.set< paths_set_node >("required_files", model::paths_set());
      tree.set< bytes_node >("required_memory", units::bytes(0));
      tree.set< paths_set_node >("required_programs", model::paths_set());
      tree.set< user_node >("required_user", "");
      // TODO(jmmv): We shouldn't be setting a default timeout like this.  See
      // Issue 5 for details.
      tree.set< delta_node >("timeout", datetime::delta(300, 0));
  }
  
  
  /// Queries the global defaults tree object with lazy initialization.
  ///
  /// \return A metadata tree.  This object is statically allocated so it is
  /// acceptable to obtain references to it and its members.
  const config::tree&
  get_defaults(void)
  {
      if (!defaults) {
          config::tree props;
          init_tree(props);
          set_defaults(props);
          defaults = props;
      }
      return defaults.get();
  }
  
  
  /// Looks up a value in a tree with error rewriting.
  ///
  /// \tparam NodeType The type of the node.
  /// \param tree The tree in which to insert the value.
  /// \param key The key to set.
  ///
  /// \return A read-write reference to the value in the node.
  ///
  /// \throw model::error If the key is not known or if the value is not valid.
  template< class NodeType >
  typename NodeType::value_type&
  lookup_rw(config::tree& tree, const std::string& key)
  {
      try {
          return tree.lookup_rw< NodeType >(key);
      } catch (const config::unknown_key_error& e) {
          throw model::error(F("Unknown metadata property %s") % key);
      } catch (const config::value_error& e) {
          throw model::error(F("Invalid value for metadata property %s: %s") %
                              key % e.what());
      }
  }
  
  
  /// Sets a value in a tree with error rewriting.
  ///
  /// \tparam NodeType The type of the node.
  /// \param tree The tree in which to insert the value.
  /// \param key The key to set.
  /// \param value The value to set the node to.
  ///
  /// \throw model::error If the key is not known or if the value is not valid.
  template< class NodeType >
  void
  set(config::tree& tree, const std::string& key,
      const typename NodeType::value_type& value)
  {
      try {
          tree.set< NodeType >(key, value);
      } catch (const config::unknown_key_error& e) {
          throw model::error(F("Unknown metadata property %s") % key);
      } catch (const config::value_error& e) {
          throw model::error(F("Invalid value for metadata property %s: %s") %
                              key % e.what());
      }
  }
  
  
  }  // anonymous namespace
  
  
  /// Internal implementation of the metadata class.
  struct model::metadata::impl : utils::noncopyable {
      /// Metadata properties.
      config::tree props;
  
      /// Constructor.
      ///
      /// \param props_ Metadata properties of the test.
      impl(const utils::config::tree& props_) :
          props(props_)
      {
      }
  
      /// Equality comparator.
      ///
      /// \param other The other object to compare this one to.
      ///
      /// \return True if this object and other are equal; false otherwise.
      bool
      operator==(const impl& other) const
      {
          return (get_defaults().combine(props) ==
                  get_defaults().combine(other.props));
      }
  };
  
  
  /// Constructor.
  ///
  /// \param props Metadata properties of the test.
  model::metadata::metadata(const utils::config::tree& props) :
      _pimpl(new impl(props))
  {
  }
  
  
  /// Destructor.
  model::metadata::~metadata(void)
  {
  }
  
  
  /// Applies a set of overrides to this metadata object.
  ///
  /// \param overrides The overrides to apply.  Any values explicitly set in this
  ///     other object will override any possible values set in this object.
  ///
  /// \return A new metadata object with the combination.
  model::metadata
  model::metadata::apply_overrides(const metadata& overrides) const
  {
      return metadata(_pimpl->props.combine(overrides._pimpl->props));
  }
  
  
  /// Returns the architectures allowed by the test.
  ///
  /// \return Set of architectures, or empty if this does not apply.
  const model::strings_set&
  model::metadata::allowed_architectures(void) const
  {
      if (_pimpl->props.is_set("allowed_architectures")) {
          return _pimpl->props.lookup< config::strings_set_node >(
              "allowed_architectures");
      } else {
          return get_defaults().lookup< config::strings_set_node >(
              "allowed_architectures");
      }
  }
  
  
  /// Returns the platforms allowed by the test.
  ///
  /// \return Set of platforms, or empty if this does not apply.
  const model::strings_set&
  model::metadata::allowed_platforms(void) const
  {
      if (_pimpl->props.is_set("allowed_platforms")) {
          return _pimpl->props.lookup< config::strings_set_node >(
              "allowed_platforms");
      } else {
          return get_defaults().lookup< config::strings_set_node >(
              "allowed_platforms");
      }
  }
  
  
  /// Returns all the user-defined metadata properties.
  ///
  /// \return A key/value map of properties.
  model::properties_map
  model::metadata::custom(void) const
  {
      return _pimpl->props.all_properties("custom", true);
  }
  
  
  /// Returns the description of the test.
  ///
  /// \return Textual description; may be empty.
  const std::string&
  model::metadata::description(void) const
  {
      if (_pimpl->props.is_set("description")) {
          return _pimpl->props.lookup< config::string_node >("description");
      } else {
          return get_defaults().lookup< config::string_node >("description");
      }
  }
  
  
  /// Returns whether the test has a cleanup part or not.
  ///
  /// \return True if there is a cleanup part; false otherwise.
  bool
  model::metadata::has_cleanup(void) const
  {
      if (_pimpl->props.is_set("has_cleanup")) {
          return _pimpl->props.lookup< config::bool_node >("has_cleanup");
      } else {
          return get_defaults().lookup< config::bool_node >("has_cleanup");
      }
  }
  
  
  /// Returns whether the test is exclusive or not.
  ///
  /// \return True if the test has to be run on its own, not concurrently with any
  /// other tests; false otherwise.
  bool
  model::metadata::is_exclusive(void) const
  {
      if (_pimpl->props.is_set("is_exclusive")) {
          return _pimpl->props.lookup< config::bool_node >("is_exclusive");
      } else {
          return get_defaults().lookup< config::bool_node >("is_exclusive");
      }
  }
  
  
  /// Returns the list of configuration variables needed by the test.
  ///
  /// \return Set of configuration variables.
  const model::strings_set&
  model::metadata::required_configs(void) const
  {
      if (_pimpl->props.is_set("required_configs")) {
          return _pimpl->props.lookup< config::strings_set_node >(
              "required_configs");
      } else {
          return get_defaults().lookup< config::strings_set_node >(
              "required_configs");
      }
  }
  
  
  /// Returns the amount of free disk space required by the test.
  ///
  /// \return Number of bytes, or 0 if this does not apply.
  const units::bytes&
  model::metadata::required_disk_space(void) const
  {
      if (_pimpl->props.is_set("required_disk_space")) {
          return _pimpl->props.lookup< bytes_node >("required_disk_space");
      } else {
          return get_defaults().lookup< bytes_node >("required_disk_space");
      }
  }
  
  
  /// Returns the list of files needed by the test.
  ///
  /// \return Set of paths.
  const model::paths_set&
  model::metadata::required_files(void) const
  {
      if (_pimpl->props.is_set("required_files")) {
          return _pimpl->props.lookup< paths_set_node >("required_files");
      } else {
          return get_defaults().lookup< paths_set_node >("required_files");
      }
  }
  
  
  /// Returns the amount of memory required by the test.
  ///
  /// \return Number of bytes, or 0 if this does not apply.
  const units::bytes&
  model::metadata::required_memory(void) const
  {
      if (_pimpl->props.is_set("required_memory")) {
          return _pimpl->props.lookup< bytes_node >("required_memory");
      } else {
          return get_defaults().lookup< bytes_node >("required_memory");
      }
  }
  
  
  /// Returns the list of programs needed by the test.
  ///
  /// \return Set of paths.
  const model::paths_set&
  model::metadata::required_programs(void) const
  {
      if (_pimpl->props.is_set("required_programs")) {
          return _pimpl->props.lookup< paths_set_node >("required_programs");
      } else {
          return get_defaults().lookup< paths_set_node >("required_programs");
      }
  }
  
  
  /// Returns the user required by the test.
  ///
  /// \return One of unprivileged, root or empty.
  const std::string&
  model::metadata::required_user(void) const
  {
      if (_pimpl->props.is_set("required_user")) {
          return _pimpl->props.lookup< user_node >("required_user");
      } else {
          return get_defaults().lookup< user_node >("required_user");
      }
  }
  
  
  /// Returns the timeout of the test.
  ///
  /// \return A time delta; should be compared to default_timeout to see if it has
  /// been overriden.
  const datetime::delta&
  model::metadata::timeout(void) const
  {
      if (_pimpl->props.is_set("timeout")) {
          return _pimpl->props.lookup< delta_node >("timeout");
      } else {
          return get_defaults().lookup< delta_node >("timeout");
      }
  }
  
  
  /// Externalizes the metadata to a set of key/value textual pairs.
  ///
  /// \return A key/value representation of the metadata.
  model::properties_map
  model::metadata::to_properties(void) const
  {
      const config::tree fully_specified = get_defaults().combine(_pimpl->props);
      return fully_specified.all_properties();
  }
  
  
  /// Equality comparator.
  ///
  /// \param other The other object to compare this one to.
  ///
  /// \return True if this object and other are equal; false otherwise.
  bool
  model::metadata::operator==(const metadata& other) const
  {
      return _pimpl == other._pimpl || *_pimpl == *other._pimpl;
  }
  
  
  /// Inequality comparator.
  ///
  /// \param other The other object to compare this one to.
  ///
  /// \return True if this object and other are different; false otherwise.
  bool
  model::metadata::operator!=(const metadata& other) const
  {
      return !(*this == other);
  }
  
  
  /// Injects the object into a stream.
  ///
  /// \param output The stream into which to inject the object.
  /// \param object The object to format.
  ///
  /// \return The output stream.
  std::ostream&
  model::operator<<(std::ostream& output, const metadata& object)
  {
      output << "metadata{";
  
      bool first = true;
      const model::properties_map props = object.to_properties();
      for (model::properties_map::const_iterator iter = props.begin();
           iter != props.end(); ++iter) {
          if (!first)
              output << ", ";
          output << F("%s=%s") % (*iter).first %
              text::quote((*iter).second, '\'');
          first = false;
      }
  
      output << "}";
      return output;
  }
  
  
  /// Internal implementation of the metadata_builder class.
  struct model::metadata_builder::impl : utils::noncopyable {
      /// Collection of requirements.
      config::tree props;
  
      /// Whether we have created a metadata object or not.
      bool built;
  
      /// Constructor.
      impl(void) :
          built(false)
      {
          init_tree(props);
      }
  
      /// Constructor.
      ///
      /// \param base The base model to construct a copy from.
      impl(const model::metadata& base) :
          props(base._pimpl->props.deep_copy()),
          built(false)
      {
      }
  };
  
  
  /// Constructor.
  model::metadata_builder::metadata_builder(void) :
      _pimpl(new impl())
  {
  }
  
  
  /// Constructor.
  model::metadata_builder::metadata_builder(const model::metadata& base) :
      _pimpl(new impl(base))
  {
  }
  
  
  /// Destructor.
  model::metadata_builder::~metadata_builder(void)
  {
  }
  
  
  /// Accumulates an additional allowed architecture.
  ///
  /// \param arch The architecture.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid.
  model::metadata_builder&
  model::metadata_builder::add_allowed_architecture(const std::string& arch)
  {
      if (!_pimpl->props.is_set("allowed_architectures")) {
          _pimpl->props.set< config::strings_set_node >(
              "allowed_architectures",
              get_defaults().lookup< config::strings_set_node >(
                  "allowed_architectures"));
      }
      lookup_rw< config::strings_set_node >(
          _pimpl->props, "allowed_architectures").insert(arch);
      return *this;
  }
  
  
  /// Accumulates an additional allowed platform.
  ///
  /// \param platform The platform.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid.
  model::metadata_builder&
  model::metadata_builder::add_allowed_platform(const std::string& platform)
  {
      if (!_pimpl->props.is_set("allowed_platforms")) {
          _pimpl->props.set< config::strings_set_node >(
              "allowed_platforms",
              get_defaults().lookup< config::strings_set_node >(
                  "allowed_platforms"));
      }
      lookup_rw< config::strings_set_node >(
          _pimpl->props, "allowed_platforms").insert(platform);
      return *this;
  }
  
  
  /// Accumulates a single user-defined property.
  ///
  /// \param key Name of the property to define.
  /// \param value Value of the property.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid.
  model::metadata_builder&
  model::metadata_builder::add_custom(const std::string& key,
                                       const std::string& value)
  {
      _pimpl->props.set_string(F("custom.%s") % key, value);
      return *this;
  }
  
  
  /// Accumulates an additional required configuration variable.
  ///
  /// \param var The name of the configuration variable.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid.
  model::metadata_builder&
  model::metadata_builder::add_required_config(const std::string& var)
  {
      if (!_pimpl->props.is_set("required_configs")) {
          _pimpl->props.set< config::strings_set_node >(
              "required_configs",
              get_defaults().lookup< config::strings_set_node >(
                  "required_configs"));
      }
      lookup_rw< config::strings_set_node >(
          _pimpl->props, "required_configs").insert(var);
      return *this;
  }
  
  
  /// Accumulates an additional required file.
  ///
  /// \param path The path to the file.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid.
  model::metadata_builder&
  model::metadata_builder::add_required_file(const fs::path& path)
  {
      if (!_pimpl->props.is_set("required_files")) {
          _pimpl->props.set< paths_set_node >(
              "required_files",
              get_defaults().lookup< paths_set_node >("required_files"));
      }
      lookup_rw< paths_set_node >(_pimpl->props, "required_files").insert(path);
      return *this;
  }
  
  
  /// Accumulates an additional required program.
  ///
  /// \param path The path to the program.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid.
  model::metadata_builder&
  model::metadata_builder::add_required_program(const fs::path& path)
  {
      if (!_pimpl->props.is_set("required_programs")) {
          _pimpl->props.set< paths_set_node >(
              "required_programs",
              get_defaults().lookup< paths_set_node >("required_programs"));
      }
      lookup_rw< paths_set_node >(_pimpl->props,
                                  "required_programs").insert(path);
      return *this;
  }
  
  
  /// Sets the architectures allowed by the test.
  ///
  /// \param as Set of architectures.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid.
  model::metadata_builder&
  model::metadata_builder::set_allowed_architectures(
      const model::strings_set& as)
  {
      set< config::strings_set_node >(_pimpl->props, "allowed_architectures", as);
      return *this;
  }
  
  
  /// Sets the platforms allowed by the test.
  ///
  /// \return ps Set of platforms.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid.
  model::metadata_builder&
  model::metadata_builder::set_allowed_platforms(const model::strings_set& ps)
  {
      set< config::strings_set_node >(_pimpl->props, "allowed_platforms", ps);
      return *this;
  }
  
  
  /// Sets the user-defined properties.
  ///
  /// \param props The custom properties to set.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid.
  model::metadata_builder&
  model::metadata_builder::set_custom(const model::properties_map& props)
  {
      for (model::properties_map::const_iterator iter = props.begin();
           iter != props.end(); ++iter)
          _pimpl->props.set_string(F("custom.%s") % (*iter).first,
                                   (*iter).second);
      return *this;
  }
  
  
  /// Sets the description of the test.
  ///
  /// \param description Textual description of the test.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid.
  model::metadata_builder&
  model::metadata_builder::set_description(const std::string& description)
  {
      set< config::string_node >(_pimpl->props, "description", description);
      return *this;
  }
  
  
  /// Sets whether the test has a cleanup part or not.
  ///
  /// \param cleanup True if the test has a cleanup part; false otherwise.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid.
  model::metadata_builder&
  model::metadata_builder::set_has_cleanup(const bool cleanup)
  {
      set< config::bool_node >(_pimpl->props, "has_cleanup", cleanup);
      return *this;
  }
  
  
  /// Sets whether the test is exclusive or not.
  ///
  /// \param exclusive True if the test is exclusive; false otherwise.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid.
  model::metadata_builder&
  model::metadata_builder::set_is_exclusive(const bool exclusive)
  {
      set< config::bool_node >(_pimpl->props, "is_exclusive", exclusive);
      return *this;
  }
  
  
  /// Sets the list of configuration variables needed by the test.
  ///
  /// \param vars Set of configuration variables.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid.
  model::metadata_builder&
  model::metadata_builder::set_required_configs(const model::strings_set& vars)
  {
      set< config::strings_set_node >(_pimpl->props, "required_configs", vars);
      return *this;
  }
  
  
  /// Sets the amount of free disk space required by the test.
  ///
  /// \param bytes Number of bytes.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid.
  model::metadata_builder&
  model::metadata_builder::set_required_disk_space(const units::bytes& bytes)
  {
      set< bytes_node >(_pimpl->props, "required_disk_space", bytes);
      return *this;
  }
  
  
  /// Sets the list of files needed by the test.
  ///
  /// \param files Set of paths.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid.
  model::metadata_builder&
  model::metadata_builder::set_required_files(const model::paths_set& files)
  {
      set< paths_set_node >(_pimpl->props, "required_files", files);
      return *this;
  }
  
  
  /// Sets the amount of memory required by the test.
  ///
  /// \param bytes Number of bytes.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid.
  model::metadata_builder&
  model::metadata_builder::set_required_memory(const units::bytes& bytes)
  {
      set< bytes_node >(_pimpl->props, "required_memory", bytes);
      return *this;
  }
  
  
  /// Sets the list of programs needed by the test.
  ///
  /// \param progs Set of paths.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid.
  model::metadata_builder&
  model::metadata_builder::set_required_programs(const model::paths_set& progs)
  {
      set< paths_set_node >(_pimpl->props, "required_programs", progs);
      return *this;
  }
  
  
  /// Sets the user required by the test.
  ///
  /// \param user One of unprivileged, root or empty.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid.
  model::metadata_builder&
  model::metadata_builder::set_required_user(const std::string& user)
  {
      set< user_node >(_pimpl->props, "required_user", user);
      return *this;
  }
  
  
  /// Sets a metadata property by name from its textual representation.
  ///
  /// \param key The property to set.
  /// \param value The value to set the property to.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid or the key does not exist.
  model::metadata_builder&
  model::metadata_builder::set_string(const std::string& key,
                                      const std::string& value)
  {
      try {
          _pimpl->props.set_string(key, value);
      } catch (const config::unknown_key_error& e) {
          throw model::format_error(F("Unknown metadata property %s") % key);
      } catch (const config::value_error& e) {
          throw model::format_error(
              F("Invalid value for metadata property %s: %s") % key % e.what());
      }
      return *this;
  }
  
  
  /// Sets the timeout of the test.
  ///
  /// \param timeout The timeout to set.
  ///
  /// \return A reference to this builder.
  ///
  /// \throw model::error If the value is invalid.
  model::metadata_builder&
  model::metadata_builder::set_timeout(const datetime::delta& timeout)
  {
      set< delta_node >(_pimpl->props, "timeout", timeout);
      return *this;
  }
  
  
  /// Creates a new metadata object.
  ///
  /// \pre This has not yet been called.  We only support calling this function
  /// once due to the way the internal tree works: we pass around references, not
  /// deep copies, so if we allowed a second build, we'd encourage reusing the
  /// same builder to construct different metadata objects, and this could have
  /// unintended consequences.
  ///
  /// \return The constructed metadata object.
  model::metadata
  model::metadata_builder::build(void) const
  {
      PRE(!_pimpl->built);
      _pimpl->built = true;
  
      return metadata(_pimpl->props);
  }
  