More perf work:

  * Move #set_cookie and #delete_cookie inline to optimize. These optimizations should
    almost certainly be sent back upstream to Rack. The optimization involves using
    an ivar for cookies instead of indexing into the headers each time.
  * Was able to use a bare Hash for headers now that cookies have their own joining
    semantics (some code assumed that the raw cookies were an Array).
  * Cache blankness of body on body=
  * Improve expand_cache_key for Arrays of a single element (common in our case)
  * Use a simple layout condition check unless conditions are used
  * Cache visible actions
  * Lazily load the UrlRewriter
  * Make etag an ivar that is set on prepare!

2 files changed, 63 insertions, 58 deletions

diff --git a/actionpack/lib/action_dispatch/http/request.rb b/actionpack/lib/action_dispatch/http/request.rb
index 958a541436..b23306af62 100755
--- a/actionpack/lib/action_dispatch/http/request.rb
+++ b/actionpack/lib/action_dispatch/http/request.rb
@@ -173,21 +173,16 @@ module ActionDispatch
         end
     end
 
-    # Expand raw_formats by converting Mime::ALL to the Mime::SET.
-    #
     def formats
-      return raw_formats
-      # if ActionController::Base.use_accept_header
-      #   raw_formats.tap do |ret|
-      #     if ret == ONLY_ALL
-      #       ret.replace Mime::SET
-      #     elsif all = ret.index(Mime::ALL)
-      #       ret.delete_at(all) && ret.insert(all, *Mime::SET)
-      #     end
-      #   end
-      # else
-      #   raw_formats + Mime::SET
-      # end
+      if ActionController::Base.use_accept_header
+        if param = parameters[:format]
+          Array.wrap(Mime[param])
+        else
+          accepts.dup
+        end
+      else
+        [format]
+      end
     end
 
     # Sets the \format by string extension, which can be used to force custom formats
@@ -488,7 +483,7 @@ EOM
     # matches the order array.
     #
     def negotiate_mime(order)
-      raw_formats.each do |priority|
+      formats.each do |priority|
         if priority == Mime::ALL
           return order.first
         elsif order.include?(priority)
@@ -501,18 +496,6 @@ EOM
 
     private
 
-      def raw_formats
-        if ActionController::Base.use_accept_header
-          if param = parameters[:format]
-            Array.wrap(Mime[param])
-          else
-            accepts.dup
-          end
-        else
-          [format]
-        end
-      end
-
       def named_host?(host)
         !(host.nil? || /\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$/.match(host))
       end
diff --git a/actionpack/lib/action_dispatch/http/response.rb b/actionpack/lib/action_dispatch/http/response.rb
index 1d3cf63984..055f29a972 100644
--- a/actionpack/lib/action_dispatch/http/response.rb
+++ b/actionpack/lib/action_dispatch/http/response.rb
@@ -32,18 +32,7 @@ module ActionDispatch # :nodoc:
   #    end
   #  end
   class Response < Rack::Response
-    class SimpleHeaderHash < Hash
-      def to_hash
-        result = {}
-        each do |k,v|
-          v = v.join("\n") if v.is_a?(Array)
-          result[k] = v
-        end
-        result
-      end
-    end
-
-    attr_accessor :request
+    attr_accessor :request, :blank
     attr_reader :cache_control
 
     attr_writer :header, :sending_file
@@ -51,19 +40,23 @@ module ActionDispatch # :nodoc:
 
     def initialize
       @status = 200
-      @header = SimpleHeaderHash.new
+      @header = {}
       @cache_control = {}
 
       @writer = lambda { |x| @body << x }
       @block = nil
       @length = 0
 
-      @body = []
+      @body, @cookie = [], []
       @sending_file = false
 
       yield self if block_given?
     end
 
+    def cache_control
+      @cache_control ||= {}
+    end
+
     def write(str)
       s = str.to_s
       @writer.call s
@@ -95,7 +88,10 @@ module ActionDispatch # :nodoc:
       str
     end
 
+    EMPTY = " "
+
     def body=(body)
+      @blank = true if body == EMPTY
       @body = body.respond_to?(:to_str) ? [body] : body
     end
 
@@ -137,19 +133,16 @@ module ActionDispatch # :nodoc:
     end
 
     def etag
-      headers['ETag']
+      @etag
     end
 
     def etag?
-      headers.include?('ETag')
+      @etag
     end
 
     def etag=(etag)
-      if etag.blank?
-        headers.delete('ETag')
-      else
-        headers['ETag'] = %("#{Digest::MD5.hexdigest(ActiveSupport::Cache.expand_cache_key(etag))}")
-      end
+      key = ActiveSupport::Cache.expand_cache_key(etag)
+      @etag = %("#{Digest::MD5.hexdigest(key)}")
     end
 
     CONTENT_TYPE    = "Content-Type"
@@ -157,7 +150,7 @@ module ActionDispatch # :nodoc:
     cattr_accessor(:default_charset) { "utf-8" }
 
     def assign_default_content_type_and_charset!
-      return if !headers[CONTENT_TYPE].blank?
+      return if headers[CONTENT_TYPE].present?
 
       @content_type ||= Mime::HTML
       @charset      ||= self.class.default_charset
@@ -171,7 +164,8 @@ module ActionDispatch # :nodoc:
     def prepare!
       assign_default_content_type_and_charset!
       handle_conditional_get!
-      self["Set-Cookie"] ||= ""
+      self["Set-Cookie"] = @cookie.join("\n")
+      self["ETag"]       = @etag if @etag
     end
 
     def each(&callback)
@@ -197,7 +191,7 @@ module ActionDispatch # :nodoc:
     #   assert_equal 'AuthorOfNewPage', r.cookies['author']
     def cookies
       cookies = {}
-      if header = headers['Set-Cookie']
+      if header = @cookie
         header = header.split("\n") if header.respond_to?(:to_str)
         header.each do |cookie|
           if pair = cookie.split(';').first
@@ -209,9 +203,40 @@ module ActionDispatch # :nodoc:
       cookies
     end
 
+    def set_cookie(key, value)
+      case value
+      when Hash
+        domain  = "; domain="  + value[:domain]    if value[:domain]
+        path    = "; path="    + value[:path]      if value[:path]
+        # According to RFC 2109, we need dashes here.
+        # N.B.: cgi.rb uses spaces...
+        expires = "; expires=" + value[:expires].clone.gmtime.
+          strftime("%a, %d-%b-%Y %H:%M:%S GMT")    if value[:expires]
+        secure = "; secure"  if value[:secure]
+        httponly = "; HttpOnly" if value[:httponly]
+        value = value[:value]
+      end
+      value = [value]  unless Array === value
+      cookie = Rack::Utils.escape(key) + "=" +
+        value.map { |v| Rack::Utils.escape v }.join("&") +
+        "#{domain}#{path}#{expires}#{secure}#{httponly}"
+
+      @cookie << cookie
+    end
+
+    def delete_cookie(key, value={})
+      @cookie.reject! { |cookie|
+        cookie =~ /\A#{Rack::Utils.escape(key)}=/
+      }
+
+      set_cookie(key,
+                 {:value => '', :path => nil, :domain => nil,
+                   :expires => Time.at(0) }.merge(value))
+    end
+
     private
       def handle_conditional_get!
-        if etag? || last_modified? || !cache_control.empty?
+        if etag? || last_modified? || !@cache_control.empty?
           set_conditional_cache_control!
         elsif nonempty_ok_response?
           self.etag = @body
@@ -227,21 +252,18 @@ module ActionDispatch # :nodoc:
         end
       end
 
-      EMPTY_RESPONSE = [" "]
-
       def nonempty_ok_response?
-        ok = !@status || @status == 200
-        ok && string_body? && @body != EMPTY_RESPONSE
+        @status == 200 && string_body?
       end
 
       def string_body?
-        !body_parts.respond_to?(:call) && body_parts.any? && body_parts.all? { |part| part.is_a?(String) }
+        !@blank && @body.respond_to?(:all?) && @body.all? { |part| part.is_a?(String) }
       end
 
       DEFAULT_CACHE_CONTROL = "max-age=0, private, must-revalidate"
 
       def set_conditional_cache_control!
-        control = cache_control
+        control = @cache_control
 
         if control.empty?
           headers["Cache-Control"] = DEFAULT_CACHE_CONTROL