Jekyll Source Code Plugin

source_codes:
  - file: ../_code/source_code.rb
    language: ruby
    title: source_code.rb
  - file: ../_code/generate_source_code.rb
    language: ruby
    title: generate_source_code.rb
  - file: ../_code/redcarpet-custom.rb
    language: ruby
    title: redcarpet-custom.rb

# John Paul Newman

module Jekyll
  class SourceCode < Liquid::Tag
    include Jekyll::Converters::Markdown::RedcarpetParser::WithPygments
    safe = true

    def initialize(tag_name, source_codes_file_filter, tokens = nil)
      super
      @source_codes_file_filter = source_codes_file_filter.strip
    end

    def render(context)
      unless context.registers[:page].key?('source_codes')
        raise 'Please include source_codes in front matter'
      end

      page_path = context.registers[:page]['path']
      page_path = page_path[0..-9] if page_path =~ %r{\/#excerpt$}
      post_path = File.dirname(page_path)

      sc = context.registers[:page]['source_codes'].find {|e| e['file'] == @source_codes_file_filter}
      if sc.nil?
        raise "Please include '#{@source_codes_file_filter}' file in source_codes within the front matter"
      end

      file_path = File.join(post_path, @source_codes_file_filter)
      text = File.open(file_path).read

      block_code(text, sc['language'], sc['file'], sc['title'])
    end
  end
end

Liquid::Template.register_tag('source_code', Jekyll::SourceCode)

# John Paul Newman

require 'fileutils'

module Jekyll
  # Monkey-patch an accessor for a page's containing folder, since
  # we need it to generate the source code.
  class Page
    def subfolder
      @dir
    end
  end

  # Sub-class Jekyll::StaticFile to allow recovery from unimportant exception
  # when writing the source code file.
  class StaticSourceCodeFile < StaticFile
    def initialize(site, base, dir, name, collection = nil, sub_path = '_code')
      super(site, base, dir, name, collection)
      @sub_path = sub_path
    end

    def write(dest)
      super(dest) rescue ArgumentError
      true
    end

    def destination(dest)
      File.join(dest, @sub_path, @name)
    end
  end

  class SourceCodeGenerator < Generator
    safe true
    priority :low

    def generate(site)
      posts = site.site_payload['site']['posts']
      posts.each do |post|
        url     = post.url
        url     = '/' + url unless url =~ %r{^\/}
        url     = url[0..-11] if url =~ %r{\/index.html$}

        next unless post.populate_tags.key?('source_code')

        post.populate_tags['source_code'].each do |sc|
          file_name = File.basename(sc['file'])
          file_subfolder = File.dirname(sc['file'])

          target_subpath = File.join(File.dirname(url), file_subfolder)
          target_path = File.join(site.config['destination'], target_subpath)

          FileUtils.mkdir_p target_path unless File.directory?(target_path)

          # source_file = File.join(File.dirname(post.path), sc['file'])

          Jekyll.logger.debug 'SourceCodeGenerator: target_path', target_path

          base_folder = File.join(site.source, '_posts')
          site.static_files << Jekyll::StaticSourceCodeFile.new(site,
                                                                base_folder,
                                                                file_subfolder,
                                                                file_name,
                                                                nil,
                                                                target_subpath)
        end
      end
    end
  end
end

# John Paul Newman
# Based On: http://manidesto.github.io/better-code-blocks-in-jekyll

module Jekyll
  module Converters
    class Markdown
      class RedcarpetParser
        module WithPygments
          include CommonMethods
          def block_code(code, lang, code_file_path=nil, title=nil)
            require 'pygments'

            lang = lang && lang.split.first || 'text'
            options = { :encoding => 'utf-8',
                        :lineanchors =>'line' }
            html = add_code_tags(
              Pygments.highlight(code,
                                 :lexer => lang,
                                 :options => options),
              lang
            )

            if lang == 'text'
              output = html
            else
              require 'nokogiri'

              html_doc = Nokogiri::HTML.fragment(html)

              header_div = Nokogiri::XML::Node.new("div", html_doc)
              header_div.content = lang
              header_div.set_attribute('class', 'code-block-header')
              header_div.content = ''

              header_left_div = Nokogiri::XML::Node.new("div", html_doc)
              header_left_div.set_attribute('class', 'code-block-header-left')
              header_left_div.content = ''

              header_div.add_child(header_left_div)

              header_right_div = Nokogiri::XML::Node.new("div", html_doc)
              header_right_div.set_attribute('class', 'code-block-header-right')
              header_right_div.content = '-'

              header_div.add_child(header_right_div)

              title ||= lang
              if code_file_path
                a = Nokogiri::XML::Node.new("a", html_doc)
                a.content = title
                a.set_attribute('href', code_file_path)

                header_left_div.add_child(a)
              end

              html_doc.first_element_child.first_element_child.add_previous_sibling(header_div)
              output = html_doc.to_s
            end
          end
        end
      end
    end
  end
end