redcarpet_codemirror.rb

require 'cgi'
require 'jekyll'
require 'redcarpet'

class RedcarpetCodeMirror < Redcarpet::Render::HTML
  def initialize
    super
    @total = 0
  end

  def codespan(code)
    code = CGI.escapeHTML(code)
    "<code>#{code}</code>"
  end

  def block_code(code, language)
    lang ||= "javascript"
    lang = "javascript" if language == ""
    lang = "bash" if lang == "shell"
    bin = "./vendor/codemirror-5.6/bin/source-highlight"
    cmd = [bin, "-s", lang]
    cmd = ["cat"]
    t1 = Time.now
    html = IO.popen(cmd, "r+") do |io|
        io.print(code)
        io.close_write
        code = io.read
        theme = "default"
        attrs = "class='cm-s-#{theme}'"
        "<pre><code #{attrs}>#{code}</code></pre>"
    end
    t2 = Time.now
    dt = t2 - t1
    @total += dt
    STDERR.puts("Time elapsed: #{t2 - t1}, total = #{@total}")
    html
  end
end

class Jekyll::Converters::Markdown::RedcarpetCodeMirror
  def initialize(config)
    @config = config
  end

  def extensions
    defaults = {
        fenced_code_blocks: true
    }
    pairs = @config['redcarpet']['extensions'].map {|e| [e.to_sym, true] }
    defaults.merge(Hash[*pairs.flatten])
  end

  def markdown
    @markdown ||= Redcarpet::Markdown.new(RedcarpetCodeMirror, extensions)
  end

  def convert(content)
    return super unless @config['markdown'] == 'RedcarpetCodeMirror'
    markdown.render(content)
  end
end