1begin
  2  require 'open3_detach'
  3rescue LoadError
  4  require 'open3'
  5end
  6
  7module GitHub
  8  module Markup
  9    extend self
 10    @@markups = {}
 11    @@deferred_markups = []
 12
 13    def preload!
 14      @@deferred_markups.each do |loader|
 15        loader.call
 16      end
 17      @@deferred_markups = []
 18    end
 19
 20    def render(filename, content = nil)
 21      content ||= File.read(filename)
 22
 23      if proc = renderer(filename)
 24        proc[content]
 25      else
 26        content
 27      end
 28    end
 29
 30    def markup(file, pattern, opts = {}, &block)
 31      loader = proc do
 32        begin
 33          require file.to_s
 34          add_markup(pattern, &block)
 35          true
 36        rescue LoadError
 37          false
 38        end
 39      end
 40
 41      if opts[:eager]
 42        loader.call
 43      else
 44        @@deferred_markups << loader
 45        add_markup pattern do |*args|
 46          @@deferred_markups.delete(loader)
 47          loader.call
 48          block.call(*args)
 49        end
 50        true
 51      end
 52    end
 53
 54    def command(command, regexp, &block)
 55      command = command.to_s
 56
 57      if File.exists?(file = File.dirname(__FILE__) + "/commands/#{command}")
 58        command = file
 59      end
 60
 61      add_markup(regexp) do |content|
 62        rendered = execute(command, content)
 63        rendered = rendered.to_s.empty? ? content : rendered
 64
 65        if block && block.arity == 2
 66          # If the block takes two arguments, pass new content and old
 67          # content.
 68          block.call(rendered, content)
 69        elsif block
 70          # One argument is just the new content.
 71          block.call(rendered)
 72        else
 73          # No block? No problem!
 74          rendered
 75        end
 76      end
 77    end
 78
 79    def add_markup(regexp, &block)
 80      @@markups[regexp] = block
 81    end
 82
 83    def can_render?(filename)
 84      !!renderer(filename)
 85    end
 86
 87    def renderer(filename)
 88      @@markups.each do |key, value|
 89        if Regexp.compile("\\.(#{key})$") =~ filename
 90          return value
 91        end
 92      end
 93      nil
 94    end
 95
 96    def renderer_name(filename)
 97      @@markups.each do |key, value|
 98        if Regexp.compile("\\.(#{key})$") =~ filename
 99          return key
100        end
101      end
102      nil
103    end
104
105    def execute(command, target)
106      out = ''
107      Open3.popen3(command) do |stdin, stdout, _|
108        stdin.puts target
109        stdin.close
110        out = stdout.read
111      end
112      out.gsub("\r", '')
113    rescue Errno::EPIPE
114      ""
115    rescue Errno::ENOENT
116      ""
117    end
118
119    # Define markups
120    markups_rb = File.dirname(__FILE__) + '/markups.rb'
121    instance_eval File.read(markups_rb), markups_rb
122  end
123end