#--
# =============================================================================
# Copyright (c) 2004, Jamis Buck (jgb3@email.byu.edu)
# 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.
# 
#     * The names of its contributors may not 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.
# =============================================================================
#++

require 'copland/configuration/errors'

module Copland
  module Configuration
    module YAML

      # This module implements type validation routines that are used by most
      # of the classes in the Copland::Configuration::YAML module.
      module TypeValidator

        # Ensures that the given +element+ (identified by the given +name+) is
        # indeed an instance of the given +klass+. If it is not, a ParserError
        # is raised.
        def ensure_element_type( name, element, klass )
          unless element.is_a?( klass )
            raise ParserError,
              "#{name.inspect} must be of type #{klass}, " +
              "not #{element.class}",
              caller[1..-1]
          end
        end

        # This requires that the +VALID_KEYS+ and +REQUIRED_KEYS+ constants have
        # been set in the including class. Then, it tests to see if the given
        # +hash+ includes any values other than those that are defined in
        # +VALID_KEYS+, or whether any keys in +REQUIRED_KEYS+ are missing from
        # +hash+. If either condition is true, a ParserError is raised. If
        # +path+ is given, it describes the location of the element (for error
        # reporting).
        def validate_elements( hash, path="" )
          path = " at #{path}" if path
          invalid_keys = hash.keys - self.class::VALID_KEYS
          unless invalid_keys.empty?
            raise ParserError,
              "invalid elements(s)#{path}: #{invalid_keys.inspect}"
          end

          missing_keys = self.class::REQUIRED_KEYS - hash.keys
          unless missing_keys.empty?
            raise ParserError,
              "missing element(s)#{path}: #{missing_keys.inspect}"
          end
        end

      end

    end
  end
end