rails/actionpack/lib/action_view/template.rb

module ActionView #:nodoc:
  class Template
    extend TemplateHandlers
    extend ActiveSupport::Memoizable
    include Renderable

    # Templates that are exempt from layouts
    @@exempt_from_layout = Set.new([/\.rjs$/])

    # Don't render layouts for templates with the given extensions.
    def self.exempt_from_layout(*extensions)
      regexps = extensions.collect do |extension|
        extension.is_a?(Regexp) ? extension : /\.#{Regexp.escape(extension.to_s)}$/
      end
      @@exempt_from_layout.merge(regexps)
    end

    attr_accessor :filename, :load_path, :base_path, :name, :format, :extension
    delegate :to_s, :to => :path

    def initialize(template_path, load_paths = [])
      template_path = template_path.dup
      @load_path, @filename = find_full_path(template_path, load_paths)
      @base_path, @name, @format, @extension = split(template_path)
      @base_path.to_s.gsub!(/\/$/, '') # Push to split method

      # Extend with partial super powers
      extend RenderablePartial if @name =~ /^_/
    end

    def accessible_paths
      paths = []
      paths << path
      paths << path_without_extension
      if multipart?
        formats = format.split(".")
        paths << "#{path_without_format_and_extension}.#{formats.first}"
        paths << "#{path_without_format_and_extension}.#{formats.second}"
      end
      paths
    end

    def format_and_extension
      (extensions = [format, extension].compact.join(".")).blank? ? nil : extensions
    end
    memoize :format_and_extension

    def multipart?
      format && format.include?('.')
    end

    def content_type
      format.gsub('.', '/')
    end

    def mime_type
      Mime::Type.lookup_by_extension(format) if format
    end
    memoize :mime_type

    def path
      [base_path, [name, format, extension].compact.join('.')].compact.join('/')
    end
    memoize :path

    def path_without_extension
      [base_path, [name, format].compact.join('.')].compact.join('/')
    end
    memoize :path_without_extension

    def path_without_format_and_extension
      [base_path, name].compact.join('/')
    end
    memoize :path_without_format_and_extension

    def relative_path
      path = File.expand_path(filename)
      path.sub!(/^#{Regexp.escape(File.expand_path(RAILS_ROOT))}\//, '') if defined?(RAILS_ROOT)
      path
    end
    memoize :relative_path

    def exempt_from_layout?
      @@exempt_from_layout.any? { |exempted| path =~ exempted }
    end

    def mtime
      File.mtime(filename)
    end
    memoize :mtime

    def source
      File.read(filename)
    end
    memoize :source

    def method_segment
      relative_path.to_s.gsub(/([^a-zA-Z0-9_])/) { $1.ord }
    end
    memoize :method_segment

    def render_template(view, local_assigns = {})
      render(view, local_assigns)
    rescue Exception => e
      raise e unless filename
      if TemplateError === e
        e.sub_template_of(self)
        raise e
      else
        raise TemplateError.new(self, view.assigns, e)
      end
    end

    def stale?
      File.mtime(filename) > mtime
    end

    def loaded?
      @loaded
    end

    def load!
      @loaded = true
      compile({})
      freeze
    end

    private
      def valid_extension?(extension)
        Template.template_handler_extensions.include?(extension)
      end

      def find_full_path(path, load_paths)
        load_paths = Array(load_paths) + [nil]
        load_paths.each do |load_path|
          file = load_path ? "#{load_path.to_str}/#{path}" : path
          return load_path, file if File.file?(file)
        end
        raise MissingTemplate.new(load_paths, path)
      end

      # Returns file split into an array
      #   [base_path, name, format, extension]
      def split(file)
        if m = file.match(/^(.*\/)?([^\.]+)\.?(\w+)?\.?(\w+)?\.?(\w+)?$/)
          if valid_extension?(m[5]) # Multipart formats
            [m[1], m[2], "#{m[3]}.#{m[4]}", m[5]]
          elsif valid_extension?(m[4]) # Single format
            [m[1], m[2], m[3], m[4]]
          elsif valid_extension?(m[3]) # No format
            [m[1], m[2], nil, m[3]]
          else # No extension
            [m[1], m[2], m[3], nil]
          end
        end
      end
  end
end