ev_core: garbage reduction with const strings

Reading headers is common and we don't want to create new String
objects (even if they're tiny or copy-on-write) for the GC to
munch on.

2 files changed, 6 insertions, 5 deletions

diff --git a/lib/rainbows/ev_core.rb b/lib/rainbows/ev_core.rb
index 23505d3..a9fc41e 100644
--- a/lib/rainbows/ev_core.rb
+++ b/lib/rainbows/ev_core.rb
@@ -18,8 +18,8 @@ module Rainbows::EvCore
       # "Transfer-Encoding: chunked", and the async.callback stuff
       # isn't Rack::Lint-compatible, so we have to enforce it here.
       headers = Rack::Utils::HeaderHash.new(headers) unless Hash === headers
-      alive = headers.include?("Content-Length") ||
-              !!(%r{\Achunked\z}i =~ headers["Transfer-Encoding"])
+      alive = headers.include?(Content_Length) ||
+              !!(%r{\Achunked\z}i =~ headers[Transfer_Encoding])
     end
     write_response(status, headers, body, alive)
   end
@@ -50,10 +50,10 @@ module Rainbows::EvCore
   # returns whether to enable response chunking for autochunk models
   def stream_response_headers(status, headers, alive)
     headers = Rack::Utils::HeaderHash.new(headers)
-    if headers['Content-Length']
+    if headers[Content_Length]
       rv = false
     else
-      rv = !!(headers['Transfer-Encoding'] =~ %r{\Achunked\z}i)
+      rv = !!(headers[Transfer_Encoding] =~ %r{\Achunked\z}i)
       rv = false if headers.delete('X-Rainbows-Autochunk') == 'no'
     end
     write_headers(status, headers, alive)
diff --git a/lib/rainbows/response.rb b/lib/rainbows/response.rb
index 4992696..111813f 100644
--- a/lib/rainbows/response.rb
+++ b/lib/rainbows/response.rb
@@ -4,6 +4,8 @@ module Rainbows::Response
   include Unicorn::HttpResponse
   Close = "close"
   KeepAlive = "keep-alive"
+  Content_Length = "Content-Length".freeze
+  Transfer_Encoding = "Transfer-Encoding".freeze
 
   # private file class for IO objects opened by Rainbows! itself (and not
   # the app or middleware)
@@ -112,7 +114,6 @@ module Rainbows::Response
   if IO.method_defined?(:sendfile_nonblock) || IO.respond_to?(:copy_stream)
     HTTP_RANGE = 'HTTP_RANGE'
     Content_Range = 'Content-Range'.freeze
-    Content_Length = 'Content-Length'.freeze
 
     # This does not support multipart responses (does anybody actually
     # use those?)