Added Blacklist/Whitelist classes

These will be used in favour of the NodeNameSet class.

lib/oga.rb

@@ -8,6 +8,8 @@ require_relative 'oga/oga'
 require_relative 'oga/lru'
 require_relative 'oga/entity_decoder'
 require_relative 'oga/node_name_set'
+require_relative 'oga/blacklist'
+require_relative 'oga/whitelist'
 
 # Load these first so that the native extensions don't have to define the
 # Oga::XML namespace.

lib/oga/blacklist.rb

@@ -0,0 +1,40 @@
+module Oga
+  ##
+  # @api private
+  #
+  class Blacklist
+    # @return [Set]
+    attr_reader :names
+
+    ##
+    # @param [Array] names
+    #
+    def initialize(names)
+      @names = Set.new(names + names.map(&:upcase))
+    end
+
+    ##
+    # @yieldparam [String]
+    #
+    def each
+      names.each do |value|
+        yield value
+      end
+    end
+
+    ##
+    # @return [TrueClass|FalseClass]
+    #
+    def allow?(name)
+      return !names.include?(name)
+    end
+
+    ##
+    # @param [Oga::Blacklist] other
+    # @return [Oga::Blacklist]
+    #
+    def +(other)
+      return self.class.new(names + other.names)
+    end
+  end # Blacklist
+end # Oga

lib/oga/whitelist.rb

@@ -0,0 +1,20 @@
+module Oga
+  ##
+  # @api private
+  #
+  class Whitelist < Blacklist
+    ##
+    # @return [TrueClass|FalseClass]
+    #
+    def allow?(name)
+      return names.include?(name)
+    end
+
+    ##
+    # @return [Oga::Blacklist]
+    #
+    def to_blacklist
+      return Blacklist.new(names)
+    end
+  end # Whitelist
+end # Oga