[RFC/PATCH] event_machine: lazily set async env keys

Eric Wong normalperson at yhbt.net
Thu Jul 15 02:03:38 EDT 2010


This has the small likelyhood of breaking apps that
check via:
   env.include?("async.callback")

Or any of member?/has_key?/key?, as they're all the same method.

>From all the async examples I see, I just see apps just
use env["async.callback"].

Worth it?

>From 40ef059dfc99c7daad1b1829713727b86c8fc9a0 Mon Sep 17 00:00:00 2001
From: Eric Wong <normalperson at yhbt.net>
Date: Thu, 15 Jul 2010 05:48:29 +0000
Subject: [PATCH] event_machine: lazily set async env keys

This is a micro-optimization when running a 'hello world' benchmark and
also reduces the strength of a memory leak under 1.9.2-rc2:

  http://redmine.ruby-lang.org/issues/show/3466
---
 lib/rainbows/ev_core.rb       |    1 -
 lib/rainbows/event_machine.rb |   17 ++++++++++++-----
 lib/rainbows/rev/client.rb    |    1 +
 3 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/lib/rainbows/ev_core.rb b/lib/rainbows/ev_core.rb
index 5ca693b..357042b 100644
--- a/lib/rainbows/ev_core.rb
+++ b/lib/rainbows/ev_core.rb
@@ -16,7 +16,6 @@ module Rainbows
 
     def post_init
       @remote_addr = Rainbows.addr(@_io)
-      @env = {}
       @hp = HttpParser.new
       @state = :headers # [ :body [ :trailers ] ] :app_call :close
       @buf = ""
diff --git a/lib/rainbows/event_machine.rb b/lib/rainbows/event_machine.rb
index 173340e..14da118 100644
--- a/lib/rainbows/event_machine.rb
+++ b/lib/rainbows/event_machine.rb
@@ -54,6 +54,17 @@ module Rainbows
       G = Rainbows::G
 
       def initialize(io)
+        @env = Hash.new do |hash,key|
+          case key
+          when ASYNC_CALLBACK
+            hash[ASYNC_CALLBACK] = method(:em_write_response)
+          when ASYNC_CLOSE
+            # we're not sure if anybody uses this, but Thin sets it, too
+            hash[ASYNC_CLOSE] = EM::DefaultDeferrable.new
+          else
+            nil
+          end
+        end
         @_io = io
         @body = nil
       end
@@ -71,10 +82,6 @@ module Rainbows
         begin
           @env[RACK_INPUT] = @input
           @env[REMOTE_ADDR] = @remote_addr
-          @env[ASYNC_CALLBACK] = method(:em_write_response)
-
-          # we're not sure if anybody uses this, but Thin sets it, too
-          @env[ASYNC_CLOSE] = EM::DefaultDeferrable.new
 
           response = catch(:async) { APP.call(@env.update(RACK_DEFAULTS)) }
 
@@ -143,7 +150,7 @@ module Rainbows
       end
 
       def unbind
-        async_close = @env[ASYNC_CLOSE] and async_close.succeed
+        @env.include?(ASYNC_CLOSE) and @env[ASYNC_CLOSE].succeed
         @body.respond_to?(:fail) and @body.fail
         @_io.close
       end
diff --git a/lib/rainbows/rev/client.rb b/lib/rainbows/rev/client.rb
index d08992b..0df7415 100644
--- a/lib/rainbows/rev/client.rb
+++ b/lib/rainbows/rev/client.rb
@@ -15,6 +15,7 @@ module Rainbows
         CONN[self] = false
         super(io)
         post_init
+        @env = {}
         @deferred_bodies = [] # for (fast) regular files only
       end
 
-- 
Eric Wong


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