require 'erb'

class ERB
  module Util
    HTML_ESCAPE = { '&' => '&amp;', '"' => '&quot;', '>' => '&gt;', '<' => '&lt;' }

    def html_escape(s)
      s.to_s.gsub(/[&\"><]/) { |special| HTML_ESCAPE[special] }
    end
  end
end

module ActionView #:nodoc:
  class ActionViewError < StandardError #:nodoc:
  end

  # Action View templates can be written in three ways. If the template file has a +.erb+ (or +.rhtml+) extension then it uses a mixture of ERb 
  # (included in Ruby) and HTML. If the template file has a +.builder+ (or +.rxml+) extension then Jim Weirich's Builder::XmlMarkup library is used. 
  # If the template file has a +.rjs+ extension then it will use ActionView::Helpers::PrototypeHelper::JavaScriptGenerator.
  # 
  # = ERb
  # 
  # You trigger ERb by using embeddings such as <% %>, <% -%>, and <%= %>. The <%= %> tag set is used when you want output. Consider the 
  # following loop for names:
  #
  #   <b>Names of all the people</b>
  #   <% for person in @people %>
  #     Name: <%= person.name %><br/>
  #   <% end %>
  #
  # The loop is setup in regular embedding tags <% %> and the name is written using the output embedding tag <%= %>. Note that this
  # is not just a usage suggestion. Regular output functions like print or puts won't work with ERb templates. So this would be wrong:
  #
  #   Hi, Mr. <% puts "Frodo" %>
  #
  # If you absolutely must write from within a function, you can use the TextHelper#concat
  #
  # <%- and -%> suppress leading and trailing whitespace, including the trailing newline, and can be used interchangeably with <% and %>.
  #
  # == Using sub templates
  #
  # Using sub templates allows you to sidestep tedious replication and extract common display structures in shared templates. The
  # classic example is the use of a header and footer (even though the Action Pack-way would be to use Layouts):
  #
  #   <%= render "shared/header" %>
  #   Something really specific and terrific
  #   <%= render "shared/footer" %>
  #
  # As you see, we use the output embeddings for the render methods. The render call itself will just return a string holding the
  # result of the rendering. The output embedding writes it to the current template.
  #
  # But you don't have to restrict yourself to static includes. Templates can share variables amongst themselves by using instance
  # variables defined using the regular embedding tags. Like this:
  #
  #   <% @page_title = "A Wonderful Hello" %>
  #   <%= render "shared/header" %>
  #
  # Now the header can pick up on the @page_title variable and use it for outputting a title tag:
  #
  #   <title><%= @page_title %></title>
  #
  # == Passing local variables to sub templates
  # 
  # You can pass local variables to sub templates by using a hash with the variable names as keys and the objects as values:
  #
  #   <%= render "shared/header", { :headline => "Welcome", :person => person } %>
  #
  # These can now be accessed in shared/header with:
  #
  #   Headline: <%= headline %>
  #   First name: <%= person.first_name %>
  #
  # If you need to find out whether a certain local variable has been assigned a value in a particular render call,
  # you need to use the following pattern:
  #
  #   <% if local_assigns.has_key? :headline %>
  #     Headline: <%= headline %>
  #   <% end %>
  #
  # Testing using <tt>defined? headline</tt> will not work. This is an implementation restriction.
  #
  # == Template caching
  #
  # By default, Rails will compile each template to a method in order to render it. When you alter a template, Rails will
  # check the file's modification time and recompile it.
  #
  # == Builder
  #
  # Builder templates are a more programmatic alternative to ERb. They are especially useful for generating XML content. An +XmlMarkup+ object 
  # named +xml+ is automatically made available to templates with a +.builder+ extension. 
  #
  # Here are some basic examples:
  #
  #   xml.em("emphasized")                              # => <em>emphasized</em>
  #   xml.em { xml.b("emph & bold") }                    # => <em><b>emph &amp; bold</b></em>
  #   xml.a("A Link", "href"=>"http://onestepback.org") # => <a href="http://onestepback.org">A Link</a>
  #   xml.target("name"=>"compile", "option"=>"fast")   # => <target option="fast" name="compile"\>
  #                                                     # NOTE: order of attributes is not specified.
  # 
  # Any method with a block will be treated as an XML markup tag with nested markup in the block. For example, the following:
  #
  #   xml.div {
  #     xml.h1(@person.name)
  #     xml.p(@person.bio)
  #   }
  #
  # would produce something like:
  #
  #   <div>
  #     <h1>David Heinemeier Hansson</h1>
  #     <p>A product of Danish Design during the Winter of '79...</p>
  #   </div>
  #
  # A full-length RSS example actually used on Basecamp:
  #
  #   xml.rss("version" => "2.0", "xmlns:dc" => "http://purl.org/dc/elements/1.1/") do
  #     xml.channel do
  #       xml.title(@feed_title)
  #       xml.link(@url)
  #       xml.description "Basecamp: Recent items"
  #       xml.language "en-us"
  #       xml.ttl "40"
  # 
  #       for item in @recent_items
  #         xml.item do
  #           xml.title(item_title(item))
  #           xml.description(item_description(item)) if item_description(item)
  #           xml.pubDate(item_pubDate(item))
  #           xml.guid(@person.firm.account.url + @recent_items.url(item))
  #           xml.link(@person.firm.account.url + @recent_items.url(item))
  #       
  #           xml.tag!("dc:creator", item.author_name) if item_has_creator?(item)
  #         end
  #       end
  #     end
  #   end
  #
  # More builder documentation can be found at http://builder.rubyforge.org.
  #
  # == JavaScriptGenerator
  #
  # JavaScriptGenerator templates end in +.rjs+. Unlike conventional templates which are used to 
  # render the results of an action, these templates generate instructions on how to modify an already rendered page. This makes it easy to 
  # modify multiple elements on your page in one declarative Ajax response. Actions with these templates are called in the background with Ajax 
  # and make updates to the page where the request originated from.
  # 
  # An instance of the JavaScriptGenerator object named +page+ is automatically made available to your template, which is implicitly wrapped in an ActionView::Helpers::PrototypeHelper#update_page block. 
  #
  # When an .rjs action is called with +link_to_remote+, the generated JavaScript is automatically evaluated.  Example:
  #
  #   link_to_remote :url => {:action => 'delete'}
  #
  # The subsequently rendered +delete.rjs+ might look like:
  #
  #   page.replace_html  'sidebar', :partial => 'sidebar'
  #   page.remove        "person-#{@person.id}"
  #   page.visual_effect :highlight, 'user-list' 
  #
  # This refreshes the sidebar, removes a person element and highlights the user list.
  # 
  # See the ActionView::Helpers::PrototypeHelper::GeneratorMethods documentation for more details.
  class Base
    include ERB::Util

    attr_reader   :first_render
    attr_accessor :base_path, :assigns, :template_extension
    attr_accessor :controller, :view_paths

    attr_reader :logger, :response, :headers
    attr_internal :cookies, :flash, :headers, :params, :request, :response, :session
    
    attr_writer :template_format

    # Specify trim mode for the ERB compiler. Defaults to '-'.
    # See ERb documentation for suitable values.
    @@erb_trim_mode = '-'
    cattr_accessor :erb_trim_mode

    # Specify whether file modification times should be checked to see if a template needs recompilation
    @@cache_template_loading = false
    cattr_accessor :cache_template_loading

    # Specify whether file extension lookup should be cached, and whether template base path lookup should be cached.
    # Should be +false+ for development environments. Defaults to +true+.
    @@cache_template_extensions = true
    cattr_accessor :cache_template_extensions

    # Specify whether local_assigns should be able to use string keys.
    # Defaults to +true+. String keys are deprecated and will be removed
    # shortly.
    @@local_assigns_support_string_keys = true
    cattr_accessor :local_assigns_support_string_keys
    
    # Specify whether RJS responses should be wrapped in a try/catch block
    # that alert()s the caught exception (and then re-raises it). 
    @@debug_rjs = false
    cattr_accessor :debug_rjs
    
    @@erb_variable = '_erbout'
    cattr_accessor :erb_variable
    
    # A regular expression of the valid characters used to separate protocols like
    # the ':' in 'http://foo.com'
    @@sanitized_protocol_separator = /:|(&#0*58)|(&#x70)|(%|&#37;)3A/
    cattr_accessor :sanitized_protocol_separator

    # Specifies a Set of HTML attributes that can have URIs.
    @@sanitized_uri_attributes = Set.new(%w(href src cite action longdesc xlink:href lowsrc))
    cattr_reader :sanitized_uri_attributes

    # Adds valid HTML attributes that the #sanitize helper checks for URIs.
    #
    #   Rails::Initializer.run do |config|
    #     config.action_view.sanitized_uri_attributes = 'lowsrc', 'target'
    #   end
    #
    def self.sanitized_uri_attributes=(attributes)
      @@sanitized_uri_attributes.merge(attributes)
    end

    # Specifies a Set of 'bad' tags that the #sanitize helper will remove completely, as opposed
    # to just escaping harmless tags like &lt;font&gt;
    @@sanitized_bad_tags = Set.new('script')
    cattr_reader :sanitized_bad_tags
    
    # Adds to the Set of 'bad' tags for the #sanitize helper.
    #
    #   Rails::Initializer.run do |config|
    #     config.action_view.sanitized_bad_tags = 'embed', 'object'
    #   end
    #
    def self.sanitized_bad_tags=(attributes)
      @@sanitized_bad_tags.merge(attributes)
    end
    
    # Specifies the default Set of tags that the #sanitize helper will allow unscathed.
    @@sanitized_allowed_tags = Set.new(%w(strong em b i p code pre tt output samp kbd var sub 
      sup dfn cite big small address hr br div span h1 h2 h3 h4 h5 h6 ul ol li dt dd abbr 
      acronym a img blockquote del ins fieldset legend))
    cattr_reader :sanitized_allowed_tags

    # Adds to the Set of allowed tags for the #sanitize helper.
    #
    #   Rails::Initializer.run do |config|
    #     config.action_view.sanitized_allowed_tags = 'table', 'tr', 'td'
    #   end
    #
    def self.sanitized_allowed_tags=(attributes)
      @@sanitized_allowed_tags.merge(attributes)
    end

    # Specifies the default Set of html attributes that the #sanitize helper will leave 
    # in the allowed tag.
    @@sanitized_allowed_attributes = Set.new(%w(href src width height alt cite datetime title class name xml:lang abbr))
    cattr_reader :sanitized_allowed_attributes

    # Adds to the Set of allowed html attributes for the #sanitize helper.
    #
    #   Rails::Initializer.run do |config|
    #     config.action_view.sanitized_allowed_attributes = 'onclick', 'longdesc'
    #   end
    #
    def self.sanitized_allowed_attributes=(attributes)
      @@sanitized_allowed_attributes.merge(attributes)
    end

    # Specifies the default Set of acceptable css properties that #sanitize and #sanitize_css will accept.
    @@sanitized_allowed_css_properties = Set.new(%w(azimuth background-color border-bottom-color border-collapse 
      border-color border-left-color border-right-color border-top-color clear color cursor direction display 
      elevation float font font-family font-size font-style font-variant font-weight height letter-spacing line-height
      overflow pause pause-after pause-before pitch pitch-range richness speak speak-header speak-numeral speak-punctuation
      speech-rate stress text-align text-decoration text-indent unicode-bidi vertical-align voice-family volume white-space
      width))
    cattr_reader :sanitized_allowed_css_properties

    # Adds to the Set of allowed css properties for the #sanitize and #sanitize_css heleprs.
    #
    #   Rails::Initializer.run do |config|
    #     config.action_view.sanitized_allowed_css_properties = 'expression'
    #   end
    #
    def self.sanitized_allowed_css_properties=(attributes)
      @@sanitized_allowed_css_properties.merge(attributes)
    end
    
    # Specifies the default Set of acceptable css keywords that #sanitize and #sanitize_css will accept.
    @@sanitized_allowed_css_keywords = Set.new(%w(auto aqua black block blue bold both bottom brown center
      collapse dashed dotted fuchsia gray green !important italic left lime maroon medium none navy normal
      nowrap olive pointer purple red right solid silver teal top transparent underline white yellow))
    cattr_reader :sanitized_allowed_css_keywords

    # Adds to the Set of allowed css keywords for the #sanitize and #sanitize_css helpers.
    #
    #   Rails::Initializer.run do |config|
    #     config.action_view.sanitized_allowed_css_keywords = 'expression'
    #   end
    #
    def self.sanitized_allowed_css_keywords=(attributes)
      @@sanitized_allowed_css_keywords.merge(attributes)
    end
    
    # Specifies the default Set of allowed shorthand css properties for the #sanitize and #sanitize_css helpers.
    @@sanitized_shorthand_css_properties = Set.new(%w(background border margin padding))
    cattr_reader :sanitized_shorthand_css_properties

    # Adds to the Set of allowed shorthand css properties for the #sanitize and #sanitize_css helpers.
    #
    #   Rails::Initializer.run do |config|
    #     config.action_view.sanitized_shorthand_css_properties = 'expression'
    #   end
    #
    def self.sanitized_shorthand_css_properties=(attributes)
      @@sanitized_shorthand_css_properties.merge(attributes)
    end

    # Specifies the default Set of protocols that the #sanitize helper will leave in
    # protocol attributes.
    @@sanitized_allowed_protocols = Set.new(%w(ed2k ftp http https irc mailto news gopher nntp telnet webcal xmpp callto feed svn urn aim rsync tag ssh sftp rtsp afs))
    cattr_reader :sanitized_allowed_protocols

    # Adds to the Set of allowed protocols for the #sanitize helper.
    #
    #   Rails::Initializer.run do |config|
    #     config.action_view.sanitized_allowed_protocols = 'ssh', 'feed'
    #   end
    #
    def self.sanitized_allowed_protocols=(attributes)
      @@sanitized_allowed_protocols.merge(attributes)
    end

    @@template_handlers = HashWithIndifferentAccess.new
 
    module CompiledTemplates #:nodoc:
      # holds compiled template code
    end
    include CompiledTemplates

    # Maps inline templates to their method names 
    @@method_names = {}
    # Map method names to their compile time
    @@compile_time = {}
    # Map method names to the names passed in local assigns so far
    @@template_args = {}
    # Count the number of inline templates
    @@inline_template_count = 0
    # Maps template paths without extension to their file extension returned by pick_template_extension.
    # If for a given path, path.ext1 and path.ext2 exist on the file system, the order of extensions
    # used by pick_template_extension determines whether ext1 or ext2 will be stored.
    @@cached_template_extension = {}
    # Maps template paths / extensions to 
    @@cached_base_paths = {}

    @@templates_requiring_setup = Set.new(%w(builder rxml rjs))

    # Order of template handers checked by #file_exists? depending on the current #template_format
    DEFAULT_TEMPLATE_HANDLER_PREFERENCE = [:erb, :rhtml, :builder, :rxml, :javascript, :delegate]
    TEMPLATE_HANDLER_PREFERENCES = {
      :js       => [:javascript, :erb, :rhtml, :builder, :rxml, :delegate],
      :xml      => [:builder, :rxml, :erb, :rhtml, :javascript, :delegate],
      :delegate => [:delegate]
    }

    class ObjectWrapper < Struct.new(:value) #:nodoc:
    end

    def self.load_helpers #:nodoc:
      Dir.entries("#{File.dirname(__FILE__)}/helpers").sort.each do |file|
        next unless file =~ /^([a-z][a-z_]*_helper).rb$/
        require "action_view/helpers/#{$1}"
        helper_module_name = $1.camelize
        if Helpers.const_defined?(helper_module_name)
          include Helpers.const_get(helper_module_name)
        end
      end
    end

    # Register a class that knows how to handle template files with the given
    # extension. This can be used to implement new template types.
    # The constructor for the class must take the ActiveView::Base instance
    # as a parameter, and the class must implement a #render method that
    # takes the contents of the template to render as well as the Hash of
    # local assigns available to the template. The #render method ought to
    # return the rendered template as a string.
    def self.register_template_handler(extension, klass)
      TEMPLATE_HANDLER_PREFERENCES[extension.to_sym] = TEMPLATE_HANDLER_PREFERENCES[:delegate]
      @@template_handlers[extension] = klass
    end

    def initialize(view_paths = [], assigns_for_first_render = {}, controller = nil)#:nodoc:
      @view_paths = view_paths.respond_to?(:find) ? view_paths : [*view_paths].compact
      @assigns = assigns_for_first_render
      @assigns_added = nil
      @controller = controller
      @logger = controller && controller.logger 
    end

    # Renders the template present at <tt>template_path</tt>. If <tt>use_full_path</tt> is set to true, 
    # it's relative to the view_paths array, otherwise it's absolute. The hash in <tt>local_assigns</tt> 
    # is made available as local variables.
    def render_file(template_path, use_full_path = true, local_assigns = {}) #:nodoc:
      @first_render ||= template_path
      template_path_without_extension, template_extension = path_and_extension(template_path)
      if use_full_path
        if template_extension
          template_file_name = full_template_path(template_path_without_extension, template_extension)
        else
          template_extension = pick_template_extension(template_path).to_s
          unless template_extension
            raise ActionViewError, "No #{template_handler_preferences.to_sentence} template found for #{template_path} in #{view_paths.inspect}"
          end
          template_file_name = full_template_path(template_path, template_extension)
          template_extension = template_extension.gsub(/^\w+\./, '') # strip off any formats
        end
      else
        template_file_name = template_path
      end

      template_source = nil # Don't read the source until we know that it is required

      if template_file_name.blank?
        raise ActionViewError, "Couldn't find template file for #{template_path} in #{view_paths.inspect}"
      end

      begin
        render_template(template_extension, template_source, template_file_name, local_assigns)
      rescue Exception => e
        if TemplateError === e
          e.sub_template_of(template_file_name)
          raise e
        else
          raise TemplateError.new(find_base_path_for("#{template_path_without_extension}.#{template_extension}") || view_paths.first, template_file_name, @assigns, template_source, e)
        end
      end
    end
    
    # Renders the template present at <tt>template_path</tt> (relative to the view_paths array). 
    # The hash in <tt>local_assigns</tt> is made available as local variables.
    def render(options = {}, old_local_assigns = {}, &block) #:nodoc:
      if options.is_a?(String)
        render_file(options, true, old_local_assigns)
      elsif options == :update
        update_page(&block)
      elsif options.is_a?(Hash)
        options = options.reverse_merge(:type => :erb, :locals => {}, :use_full_path => true)

        if options[:layout]
          path, partial_name = partial_pieces(options.delete(:layout))

          if block_given?
            @content_for_layout = capture(&block)
            concat(render(options.merge(:partial => "#{path}/#{partial_name}")), block.binding)
          else
            @content_for_layout = render(options)
            render(options.merge(:partial => "#{path}/#{partial_name}"))
          end
        elsif options[:file]
          render_file(options[:file], options[:use_full_path], options[:locals])
        elsif options[:partial] && options[:collection]
          render_partial_collection(options[:partial], options[:collection], options[:spacer_template], options[:locals])
        elsif options[:partial]
          render_partial(options[:partial], ActionView::Base::ObjectWrapper.new(options[:object]), options[:locals])
        elsif options[:inline]
          render_template(options[:type], options[:inline], nil, options[:locals])
        end
      end
    end

    # Renders the +template+ which is given as a string as either erb or builder depending on <tt>template_extension</tt>.
    # The hash in <tt>local_assigns</tt> is made available as local variables.
    def render_template(template_extension, template, file_path = nil, local_assigns = {}) #:nodoc:
      if handler = @@template_handlers[template_extension]
        template ||= read_template_file(file_path, template_extension) # Make sure that a lazyily-read template is loaded.
        delegate_render(handler, template, local_assigns)
      else
        compile_and_render_template(template_extension, template, file_path, local_assigns)
      end
    end

    # Render the provided template with the given local assigns. If the template has not been rendered with the provided
    # local assigns yet, or if the template has been updated on disk, then the template will be compiled to a method.
    #
    # Either, but not both, of template and file_path may be nil. If file_path is given, the template
    # will only be read if it has to be compiled.
    #
    def compile_and_render_template(extension, template = nil, file_path = nil, local_assigns = {}) #:nodoc:
      # convert string keys to symbols if requested
      local_assigns = local_assigns.symbolize_keys if @@local_assigns_support_string_keys

      # compile the given template, if necessary
      if compile_template?(template, file_path, local_assigns)
        template ||= read_template_file(file_path, extension)
        compile_template(extension, template, file_path, local_assigns)
      end

      # Get the method name for this template and run it
      method_name = @@method_names[file_path || template]
      evaluate_assigns

      send(method_name, local_assigns) do |*name|
        instance_variable_get "@content_for_#{name.first || 'layout'}"
      end
    end

    # Gets the full template path with base path for the given template_path and extension.
    #
    #   full_template_path('users/show', 'html.erb')
    #   # => '~/rails/app/views/users/show.html.erb
    #
    def full_template_path(template_path, extension)
      if @@cache_template_extensions
        (@@cached_base_paths[template_path] ||= {})[extension.to_s] = find_full_template_path(template_path, extension)
      else
        find_full_template_path(template_path, extension)
      end
    end

    # Gets the extension for an existing template with the given template_path.
    # Returns the format with the extension if that template exists.
    #
    #   pick_template_extension('users/show')
    #   # => 'html.erb'
    #
    #   pick_template_extension('users/legacy')
    #   # => "rhtml"
    #
    def pick_template_extension(template_path)#:nodoc:
      if @@cache_template_extensions
        (@@cached_template_extension[template_path] ||= {})[template_format] ||= find_template_extension_for(template_path)
      else
        find_template_extension_for(template_path)
      end
    end

    def delegate_template_exists?(template_path)#:nodoc:
      delegate = @@template_handlers.find { |k,| template_exists?(template_path, k) }
      delegate && delegate.first.to_sym
    end

    def erb_template_exists?(template_path)#:nodoc:
      template_exists?(template_path, :erb)
    end

    def builder_template_exists?(template_path)#:nodoc:
      template_exists?(template_path, :builder)
    end

    def rhtml_template_exists?(template_path)#:nodoc:
      template_exists?(template_path, :rhtml)
    end

    def rxml_template_exists?(template_path)#:nodoc:
      template_exists?(template_path, :rxml)
    end

    def javascript_template_exists?(template_path)#:nodoc:
      template_exists?(template_path, :rjs)
    end

    def file_exists?(template_path)#:nodoc:
      template_file_name, template_file_extension = path_and_extension(template_path)
      if template_file_extension
        template_exists?(template_file_name, template_file_extension)
      else
        pick_template_extension(template_path)
      end
    end

    # Returns true is the file may be rendered implicitly.
    def file_public?(template_path)#:nodoc:
      template_path.split('/').last[0,1] != '_'
    end

    # symbolized version of the :format parameter of the request, or :html by default.
    def template_format
      return @template_format if @template_format
      format = controller && controller.respond_to?(:request) && controller.request.parameters[:format]
      @template_format = format.blank? ? :html : format.to_sym
    end

    def template_handler_preferences
      TEMPLATE_HANDLER_PREFERENCES[template_format] || DEFAULT_TEMPLATE_HANDLER_PREFERENCE
    end

    private
      def find_full_template_path(template_path, extension)
        file_name = "#{template_path}.#{extension}"
        base_path = find_base_path_for(file_name)
        base_path.blank? ? "" : "#{base_path}/#{file_name}"
      end

      # Asserts the existence of a template.
      def template_exists?(template_path, extension)
        file_path = full_template_path(template_path, extension)
        !file_path.blank? && @@method_names.has_key?(file_path) || FileTest.exists?(file_path)
      end

      # Splits the path and extension from the given template_path and returns as an array.
      def path_and_extension(template_path)
        template_path_without_extension = template_path.sub(/\.(\w+)$/, '')
        [ template_path_without_extension, $1 ]
      end
      
      # Returns the view path that contains the given relative template path.
      def find_base_path_for(template_file_name)
        view_paths.find { |p| File.file?(File.join(p, template_file_name)) }
      end

      # Returns the view path that the full path resides in.
      def extract_base_path_from(full_path)
        view_paths.find { |p| full_path[0..p.size - 1] == p }
      end

      # Determines the template's file extension, such as rhtml, rxml, or rjs.
      def find_template_extension_for(template_path)
        find_template_extension_from_handler(template_path, true) || find_template_extension_from_handler(template_path)
      end

      def find_template_extension_from_handler(template_path, formatted = nil)
        checked_template_path = formatted ? "#{template_path}.#{template_format}" : template_path
        template_handler_preferences.each do |template_type|
          extension =
            case template_type
              when :javascript
                template_exists?(checked_template_path, :rjs) && :rjs
              when :delegate
                delegate_template_exists?(checked_template_path)
              else
                template_exists?(checked_template_path, template_type) && template_type
            end
          if extension
            return formatted ? "#{template_format}.#{extension}" : extension.to_s
          end
        end
        nil
      end

      # This method reads a template file.
      def read_template_file(template_path, extension)
        File.read(template_path)
      end

      # Evaluate the local assigns and pushes them to the view.
      def evaluate_assigns
        unless @assigns_added
          assign_variables_from_controller
          @assigns_added = true
        end
      end

      def delegate_render(handler, template, local_assigns)
        handler.new(self).render(template, local_assigns)
      end

      # Assigns instance variables from the controller to the view.
      def assign_variables_from_controller
        @assigns.each { |key, value| instance_variable_set("@#{key}", value) }
      end


      # Return true if the given template was compiled for a superset of the keys in local_assigns
      def supports_local_assigns?(render_symbol, local_assigns)
        local_assigns.empty? ||
          ((args = @@template_args[render_symbol]) && local_assigns.all? { |k,_| args.has_key?(k) })
      end

      # Method to check whether template compilation is necessary.
      # The template will be compiled if the inline template or file has not been compiled yet,
      # if local_assigns has a new key, which isn't supported by the compiled code yet,
      # or if the file has changed on disk and checking file mods hasn't been disabled.
      def compile_template?(template, file_name, local_assigns)
        method_key    = file_name || template
        render_symbol = @@method_names[method_key]

        compile_time = @@compile_time[render_symbol]
        if compile_time && supports_local_assigns?(render_symbol, local_assigns)
          if file_name && !@@cache_template_loading
            template_changed_since?(file_name, compile_time)
          end
        else
          true
        end
      end

      # Method to handle checking a whether a template has changed since last compile; isolated so that templates
      # not stored on the file system can hook and extend appropriately.
      def template_changed_since?(file_name, compile_time)
        lstat = File.lstat(file_name)
        compile_time < lstat.mtime || 
          (lstat.symlink? && compile_time < File.stat(file_name).mtime)
      end

      # Method to create the source code for a given template.
      def create_template_source(extension, template, render_symbol, locals)
        if template_requires_setup?(extension)
          body = case extension.to_sym
            when :rxml, :builder
              "controller.response.content_type ||= Mime::XML\n" +
              "xml = Builder::XmlMarkup.new(:indent => 2)\n" +
              template +
              "\nxml.target!\n"
            when :rjs
              "controller.response.content_type ||= Mime::JS\n" +
              "update_page do |page|\n#{template}\nend"
          end
        else
          body = ERB.new(template, nil, @@erb_trim_mode).src
        end

        @@template_args[render_symbol] ||= {}
        locals_keys = @@template_args[render_symbol].keys | locals
        @@template_args[render_symbol] = locals_keys.inject({}) { |h, k| h[k] = true; h }

        locals_code = ""
        locals_keys.each do |key|
          locals_code << "#{key} = local_assigns[:#{key}]\n"
        end

        "def #{render_symbol}(local_assigns)\n#{locals_code}#{body}\nend"
      end

      def template_requires_setup?(extension) #:nodoc:
        @@templates_requiring_setup.include? extension.to_s
      end

      def assign_method_name(extension, template, file_name)
        method_key = file_name || template
        @@method_names[method_key] ||= compiled_method_name(extension, template, file_name)
      end

      def compiled_method_name(extension, template, file_name)
        ['_run', extension, compiled_method_name_file_path_segment(file_name)].compact.join('_').to_sym
      end

      def compiled_method_name_file_path_segment(file_name)
        if file_name
          s = File.expand_path(file_name)
          s.sub!(/^#{Regexp.escape(File.expand_path(RAILS_ROOT))}/, '') if defined?(RAILS_ROOT)
          s.gsub!(/([^a-zA-Z0-9_])/) { $1[0].to_s }
          s
        else
          (@@inline_template_count += 1).to_s
        end
      end

      # Compile and evaluate the template's code
      def compile_template(extension, template, file_name, local_assigns)
        render_symbol = assign_method_name(extension, template, file_name)
        render_source = create_template_source(extension, template, render_symbol, local_assigns.keys)

        line_offset = @@template_args[render_symbol].size
        if extension
          case extension.to_sym
          when :builder, :rxml, :rjs
            line_offset += 2
          end
        end
        
        begin
          unless file_name.blank?
            CompiledTemplates.module_eval(render_source, file_name, -line_offset)
          else
            CompiledTemplates.module_eval(render_source, 'compiled-template', -line_offset)
          end
        rescue Exception => e  # errors from template code
          if logger
            logger.debug "ERROR: compiling #{render_symbol} RAISED #{e}"
            logger.debug "Function body: #{render_source}"
            logger.debug "Backtrace: #{e.backtrace.join("\n")}"
          end

          raise TemplateError.new(extract_base_path_from(file_name) || view_paths.first, file_name || template, @assigns, template, e)
        end

        @@compile_time[render_symbol] = Time.now
        # logger.debug "Compiled template #{file_name || template}\n  ==> #{render_symbol}" if logger
      end
  end
end

require 'action_view/template_error'