[PATCH 1/2] const: drop constants used by Rainbows!

[PATCH 1/2] const: drop constants used by Rainbows!

[Eric Wong]

Rainbows! (in maintenance mode) will need to define it's own
constants in the future.  We'll trim down our constant usage in
subsequent commits as we take advantage of Ruby VM improvements.
---
 lib/unicorn/const.rb | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/lib/unicorn/const.rb b/lib/unicorn/const.rb
index 26fa62b..e24b511 100644
--- a/lib/unicorn/const.rb
+++ b/lib/unicorn/const.rb
@@ -25,14 +25,6 @@ module Unicorn::Const
   MAX_BODY = 1024 * 112
 
   # :stopdoc:
-  # common errors we'll send back
-  # (N.B. these are not used by unicorn, but we won't drop them until
-  #  unicorn 5.x to avoid breaking Rainbows!).
-  ERROR_400_RESPONSE = "HTTP/1.1 400 Bad Request\r\n\r\n"
-  ERROR_414_RESPONSE = "HTTP/1.1 414 Request-URI Too Long\r\n\r\n"
-  ERROR_413_RESPONSE = "HTTP/1.1 413 Request Entity Too Large\r\n\r\n"
-  ERROR_500_RESPONSE = "HTTP/1.1 500 Internal Server Error\r\n\r\n"
-
   EXPECT_100_RESPONSE = "HTTP/1.1 100 Continue\r\n\r\n"
   EXPECT_100_RESPONSE_SUFFIXED = "100 Continue\r\n\r\nHTTP/1.1 "
 
-- 
EW

[PATCH 2/2] reduce and localize constant string use

[Eric Wong]

Literal String#freeze avoids allocations since Ruby 2.1 via the
opt_str_freeze instruction, so we can start relying on it in
some places as Ruby 2.1 adoption increases.  The 100-continue
handling is a good place to start since it is an uncommonly-used
code path which benefits from size reduction and the negative
performance impact is restricted to a handful of users.

HTTP_RESPONSE_START can safely live in http_request.rb as its
usage does not cross namespace boundaries

The goal is to eventually eliminate Unicorn::Const entirely.
---
 lib/unicorn/const.rb        | 17 +----------------
 lib/unicorn/http_request.rb |  5 ++++-
 lib/unicorn/http_server.rb  | 18 ++++++++++--------
 3 files changed, 15 insertions(+), 25 deletions(-)

diff --git a/lib/unicorn/const.rb b/lib/unicorn/const.rb
index e24b511..33ab4ac 100644
--- a/lib/unicorn/const.rb
+++ b/lib/unicorn/const.rb
@@ -1,12 +1,6 @@
 # -*- encoding: binary -*-
 
-# :enddoc:
-# Frequently used constants when constructing requests or responses.
-# Many times the constant just refers to a string with the same
-# contents.  Using these constants gave about a 3% to 10% performance
-# improvement over using the strings directly.  Symbols did not really
-# improve things much compared to constants.
-module Unicorn::Const
+module Unicorn::Const # :nodoc:
   # default TCP listen host address (0.0.0.0, all interfaces)
   DEFAULT_HOST = "0.0.0.0"
 
@@ -23,14 +17,5 @@ module Unicorn::Const
   # temporary file for reading (112 kilobytes).  This is the default
   # value of client_body_buffer_size.
   MAX_BODY = 1024 * 112
-
-  # :stopdoc:
-  EXPECT_100_RESPONSE = "HTTP/1.1 100 Continue\r\n\r\n"
-  EXPECT_100_RESPONSE_SUFFIXED = "100 Continue\r\n\r\nHTTP/1.1 "
-
-  HTTP_RESPONSE_START = ['HTTP', '/1.1 ']
-  HTTP_EXPECT = "HTTP_EXPECT"
-
-  # :startdoc:
 end
 require_relative 'version'
diff --git a/lib/unicorn/http_request.rb b/lib/unicorn/http_request.rb
index 6b20431..9888430 100644
--- a/lib/unicorn/http_request.rb
+++ b/lib/unicorn/http_request.rb
@@ -26,8 +26,11 @@ class Unicorn::HttpParser
 
   # :stopdoc:
   # A frozen format for this is about 15% faster
+  # Drop these frozen strings when Ruby 2.2 becomes more prevalent,
+  # 2.2+ optimizes hash assignments when used with literal string keys
   REMOTE_ADDR = 'REMOTE_ADDR'.freeze
   RACK_INPUT = 'rack.input'.freeze
+  HTTP_RESPONSE_START = [ 'HTTP', '/1.1 ']
   @@input_class = Unicorn::TeeInput
   @@check_client_connection = false
 
@@ -86,7 +89,7 @@ class Unicorn::HttpParser
     # detect if the socket is valid by writing a partial response:
     if @@check_client_connection && headers?
       @response_start_sent = true
-      Unicorn::Const::HTTP_RESPONSE_START.each { |c| socket.write(c) }
+      HTTP_RESPONSE_START.each { |c| socket.write(c) }
     end
 
     e[RACK_INPUT] = 0 == content_length ?
diff --git a/lib/unicorn/http_server.rb b/lib/unicorn/http_server.rb
index c44a71e..f0216d0 100644
--- a/lib/unicorn/http_server.rb
+++ b/lib/unicorn/http_server.rb
@@ -546,12 +546,15 @@ class Unicorn::HttpServer
     rescue
   end
 
-  def expect_100_response
-    if @request.response_start_sent
-      Unicorn::Const::EXPECT_100_RESPONSE_SUFFIXED
-    else
-      Unicorn::Const::EXPECT_100_RESPONSE
-    end
+  def e100_response_write(client, env)
+    # We use String#freeze to avoid allocations under Ruby 2.1+
+    # Not many users hit this code path, so it's better to reduce the
+    # constant table sizes even for 1.9.3-2.0 users who'll hit extra
+    # allocations here.
+    client.write(@request.response_start_sent ?
+                 "100 Continue\r\n\r\nHTTP/1.1 ".freeze :
+                 "HTTP/1.1 100 Continue\r\n\r\n".freeze)
+    env.delete('HTTP_EXPECT'.freeze)
   end
 
   # once a client is accepted, it is processed in its entirety here
@@ -561,8 +564,7 @@ class Unicorn::HttpServer
     return if @request.hijacked?
 
     if 100 == status.to_i
-      client.write(expect_100_response)
-      env.delete(Unicorn::Const::HTTP_EXPECT)
+      e100_response_write(client, env)
       status, headers, body = @app.call(env)
       return if @request.hijacked?
     end
-- 
EW