Merge branch 'fixup-custom-markdown'

* fixup-custom-markdown:
  markdown: minor style fixes
  Add support for underscores.
  Refactor: lib/jekyll/convertor/markdown.rb - tests: no additions/breaks.

lib/jekyll/converters/markdown.rb

@@ -1,54 +1,59 @@
 module Jekyll
   module Converters
     class Markdown < Converter
-      safe true
-
       highlighter_prefix "\n"
       highlighter_suffix "\n"
+      safe true
 
       def setup
         return if @setup
-        @parser =
-          case @config['markdown'].downcase
-            when 'redcarpet' then RedcarpetParser.new(@config)
-            when 'kramdown'  then KramdownParser.new(@config)
-            when 'rdiscount' then RDiscountParser.new(@config)
-          else
-            # So they can't try some tricky bullshit or go down the ancestor chain, I hope.
-            if allowed_custom_class?(@config['markdown'])
-              self.class.const_get(@config['markdown']).new(@config)
-            else
-              Jekyll.logger.error "Invalid Markdown Processor:", "#{@config['markdown']}"
-              Jekyll.logger.error "", "Valid options are [ #{valid_processors.join(" | ")} ]"
-              raise Errors::FatalException, "Invalid Markdown Processor: #{@config['markdown']}"
-            end
+        if (!@parser = get_processor)
+          Jekyll.logger.error "Invalid Markdown processor given:", @config["markdown"]
+          Jekyll.logger.info  "", "Custom processors are not loaded in safe mode" if @config["safe"]
+          Jekyll.logger.error "", "Available processors are: #{valid_processors.join(", ")}"
+          raise Errors::FatalException, "Bailing out; invalid Markdown processor."
         end
+
         @setup = true
       end
 
-      def valid_processors
-        %w[
-          rdiscount
-          kramdown
-          redcarpet
-        ] + third_party_processors
+      def get_processor
+        case @config["markdown"].downcase
+          when "redcarpet" then return RedcarpetParser.new(@config)
+          when "kramdown"  then return KramdownParser.new(@config)
+          when "rdiscount" then return RDiscountParser.new(@config)
+        else
+          get_custom_processor
+        end
       end
 
+      # Public: Provides you with a list of processors, the ones we
+      # support internally and the ones that you have provided to us (if you
+      # are not in safe mode.)
+
+      def valid_processors
+        %W(rdiscount kramdown redcarpet) + third_party_processors
+      end
+
+      # Public: A list of processors that you provide via plugins.
+      # This is really only available if you are not in safe mode, if you are
+      # in safe mode (re: Github) then there will be none.
+
       def third_party_processors
-        self.class.constants - %w[
-          KramdownParser
-          RDiscountParser
-          RedcarpetParser
-          PRIORITIES
-        ].map(&:to_sym)
+        self.class.constants - \
+        %w[KramdownParser RDiscountParser RedcarpetParser PRIORITIES].map(
+          &:to_sym
+        )
       end
 
       def extname_list
-        @extname_list ||= @config['markdown_ext'].split(',').map { |e| ".#{e.downcase}" }
+        @extname_list ||= @config['markdown_ext'].split(',').map do |e|
+          ".#{e.downcase}"
+        end
       end
 
       def matches(ext)
-        extname_list.include? ext.downcase
+        extname_list.include?(ext.downcase)
       end
 
       def output_ext(ext)
@@ -61,16 +66,26 @@ module Jekyll
       end
 
       private
+      def get_custom_processor
+        converter_name = @config["markdown"]
+        if custom_class_allowed?(converter_name)
+          self.class.const_get(converter_name).new(@config)
+        end
+      end
 
-      # Private: Determine whether a class name is an allowed custom markdown
-      # class name
+      # Private: Determine whether a class name is an allowed custom
+      #   markdown class name.
       #
       # parser_name - the name of the parser class
       #
-      # Returns true if the parser name contains only alphanumeric characters
-      # and is defined within Jekyll::Converters::Markdown
-      def allowed_custom_class?(parser_name)
-        parser_name !~ /[^A-Za-z0-9]/ && self.class.constants.include?(parser_name.to_sym)
+      # Returns true if the parser name contains only alphanumeric
+      # characters and is defined within Jekyll::Converters::Markdown
+
+      private
+      def custom_class_allowed?(parser_name)
+        parser_name !~ /[^A-Za-z0-9_]/ && self.class.constants.include?(
+          parser_name.to_sym
+        )
       end
     end
   end