Remove locals dependency from template.

This means that templates does not need to store its source anymore, allowing us to reduce the ammount of memory taken by our Rails processes. Naively speaking, if your app/views contains 2MB of files, each of your processes (after being hit by a bunch of requests) will take 2MB less of memory after this commit.

This is extremely important for the upcoming features. Since Rails will also render CSS and JS files, their source won't be stored as well allowing us to decrease the ammount of memory taken.

3 files changed, 53 insertions, 41 deletions

diff --git a/actionpack/lib/action_view/render/layouts.rb b/actionpack/lib/action_view/render/layouts.rb
index 8882acca31..08162f7fd5 100644
--- a/actionpack/lib/action_view/render/layouts.rb
+++ b/actionpack/lib/action_view/render/layouts.rb
@@ -62,11 +62,11 @@ module ActionView
     # This is the method which actually finds the layout using details in the lookup
     # context object. If no layout is found, it checks if at least a layout with
     # the given name exists across all details before raising the error.
-    def find_layout(layout)
+    def find_layout(layout, keys)
       begin
         with_layout_format do
           layout =~ /^\// ?
-            with_fallbacks { find_template(layout) } : find_template(layout)
+            with_fallbacks { find_template(layout, nil, false, keys) } : find_template(layout, nil, false, keys)
         end
       rescue ActionView::MissingTemplate => e
         update_details(:formats => nil) do
diff --git a/actionpack/lib/action_view/render/partials.rb b/actionpack/lib/action_view/render/partials.rb
index cc9b444837..07e844afc2 100644
--- a/actionpack/lib/action_view/render/partials.rb
+++ b/actionpack/lib/action_view/render/partials.rb
@@ -218,7 +218,6 @@ module ActionView
       def initialize(view_context, options, block)
         @view           = view_context
         @partial_names  = PARTIAL_NAMES[@view.controller.class.name]
-
         setup(options, block)
       end
 
@@ -237,16 +236,28 @@ module ActionView
           @object = partial
 
           if @collection = collection
-            paths = @collection_paths = @collection.map { |o| partial_path(o) }
+            paths = @collection_data = @collection.map { |o| partial_path(o) }
             @path = paths.uniq.size == 1 ? paths.first : nil
           else
             @path = partial_path
           end
         end
+
+        if @path
+          @variable, @variable_counter = retrieve_variable(@path)
+        else
+          paths.map! { |path| retrieve_variable(path).unshift(path) }
+        end
+      end
+
+      def retrieve_variable(path)
+        variable = @options[:as] || path[%r'_?(\w+)(\.\w+)*$', 1].to_sym
+        variable_counter = :"#{variable}_counter" if @collection
+        [variable, variable_counter]
       end
 
       def render
-        identifier = ((@template = find_template) ? @template.identifier : @path)
+        identifier = ((@template = find_partial) ? @template.identifier : @path)
 
         if @collection
           ActiveSupport::Notifications.instrument("render_collection.action_view",
@@ -254,15 +265,16 @@ module ActionView
             render_collection
           end
         else
+          if !@block && (layout = @options[:layout])
+            layout = find_template(layout)
+          end
+
           content = ActiveSupport::Notifications.instrument("render_partial.action_view",
             :identifier => identifier) do
             render_partial
           end
 
-          if !@block && (layout = @options[:layout])
-            content = @view._render_layout(find_template(layout), @locals){ content }
-          end
-
+          content = @view._render_layout(layout, @locals){ content } if layout
           content
         end
       end
@@ -278,16 +290,9 @@ module ActionView
         result.join(spacer).html_safe
       end
 
-      def collection_with_template(template = @template)
+      def collection_with_template
         segments, locals, template = [], @locals, @template
-
-        if @options[:as]
-          as = @options[:as]
-          counter = "#{as}_counter".to_sym
-        else
-          as = template.variable_name
-          counter = template.counter_name
-        end
+        as, counter = @variable, @variable_counter
 
         locals[counter] = -1
 
@@ -300,20 +305,16 @@ module ActionView
         segments
       end
 
-      def collection_without_template(collection_paths = @collection_paths)
-        segments, locals = [], @locals
+      def collection_without_template
+        segments, locals, collection_data = [], @locals, @collection_data
         index, template  = -1, nil
-
-        if @options[:as]
-          as = @options[:as]
-          counter = "#{as}_counter"
-        end
+        keys = @locals.keys
 
         @collection.each_with_index do |object, i|
-          template = find_template(collection_paths[i])
-          locals[as || template.variable_name] = object
-          locals[counter || template.counter_name] = (index += 1)
-
+          path, *data = collection_data[i]
+          template = find_template(path, keys + data)
+          locals[data[0]] = object
+          locals[data[1]] = (index += 1)
           segments << template.render(@view, locals)
         end
 
@@ -321,13 +322,14 @@ module ActionView
         segments
       end
 
-      def render_partial(object = @object)
-        locals, view, template = @locals, @view, @template
+      def render_partial
+        locals, view = @locals, @view
+        object, as = @object, @variable
 
-        object ||= locals[template.variable_name]
-        locals[@options[:as] || template.variable_name] = object
+        object ||= locals[as]
+        locals[as] = object
 
-        template.render(view, locals) do |*name|
+        @template.render(view, locals) do |*name|
           view._layout_for(*name, &@block)
         end
       end
@@ -342,10 +344,18 @@ module ActionView
         end
       end
 
-      def find_template(path=@path)
-        return path unless path.is_a?(String)
+      def find_partial
+        if path = @path
+          locals = @locals.keys
+          locals << @variable
+          locals << @variable_counter if @collection
+          find_template(path, locals)
+        end
+      end 
+
+      def find_template(path=@path, locals=@locals.keys)
         prefix = @view.controller_path unless path.include?(?/)
-        @view.find_template(path, prefix, true)
+        @view.find_template(path, prefix, true, locals)
       end
 
       def partial_path(object = @object)
diff --git a/actionpack/lib/action_view/render/rendering.rb b/actionpack/lib/action_view/render/rendering.rb
index 5320245173..0771b40c37 100644
--- a/actionpack/lib/action_view/render/rendering.rb
+++ b/actionpack/lib/action_view/render/rendering.rb
@@ -34,16 +34,18 @@ module ActionView
 
     # Determine the template to be rendered using the given options.
     def _determine_template(options) #:nodoc:
+      keys = (options[:locals] ||= {}).keys
+
       if options.key?(:inline)
         handler = Template.handler_class_for_extension(options[:type] || "erb")
-        Template.new(options[:inline], "inline template", handler, {})
+        Template.new(options[:inline], "inline template", handler, { :locals => keys })
       elsif options.key?(:text)
         Template::Text.new(options[:text], formats.try(:first))
       elsif options.key?(:file)
-        with_fallbacks { find_template(options[:file], options[:prefix]) }
+        with_fallbacks { find_template(options[:file], options[:prefix], false, keys) }
       elsif options.key?(:template)
         options[:template].respond_to?(:render) ?
-          options[:template] : find_template(options[:template], options[:prefix])
+          options[:template] : find_template(options[:template], options[:prefix], false, keys)
       end
     end
 
@@ -51,7 +53,7 @@ module ActionView
     # supplied as well.
     def _render_template(template, layout = nil, options = {}) #:nodoc:
       locals = options[:locals] || {}
-      layout = find_layout(layout) if layout
+      layout = find_layout(layout, locals.keys) if layout
 
       ActiveSupport::Notifications.instrument("render_template.action_view",
         :identifier => template.identifier, :layout => layout.try(:virtual_path)) do