add "copy_stream" config directive

This allows using IO::Splice.copy_stream from the "io_splice"
RubyGem on recent Linux systems.  This also allows users to
disable copy_stream usage entirely and use traditional
response_body.each calls which are compatible with all Rack
servers (to workaround bugs in IO.copy_stream under 1.9.2-p180).

1 files changed, 11 insertions, 10 deletions

diff --git a/lib/rainbows/response.rb b/lib/rainbows/response.rb
index 65599e9..fac2c0e 100644
--- a/lib/rainbows/response.rb
+++ b/lib/rainbows/response.rb
@@ -6,6 +6,7 @@ module Rainbows::Response
   KeepAlive = "keep-alive"
   Content_Length = "Content-Length".freeze
   Transfer_Encoding = "Transfer-Encoding".freeze
+  Rainbows.config!(self, :copy_stream)
 
   # private file class for IO objects opened by Rainbows! itself (and not
   # the app or middleware)
@@ -67,7 +68,7 @@ module Rainbows::Response
     end
 
     # generic response writer, used for most dynamically-generated responses
-    # and also when IO.copy_stream and/or IO#trysendfile is unavailable
+    # and also when copy_stream and/or IO#trysendfile is unavailable
     def write_response(status, headers, body, alive)
       write_headers(status, headers, alive)
       write_body_each(body)
@@ -89,29 +90,29 @@ module Rainbows::Response
     include Sendfile
   end
 
-  if IO.respond_to?(:copy_stream)
+  if COPY_STREAM
     unless IO.method_defined?(:trysendfile)
       module CopyStream
         def write_body_file(body, range)
-          range ? IO.copy_stream(body, self, range[1], range[0]) :
-                  IO.copy_stream(body, self, nil, 0)
+          range ? COPY_STREAM.copy_stream(body, self, range[1], range[0]) :
+                  COPY_STREAM.copy_stream(body, self, nil, 0)
         end
       end
       include CopyStream
     end
 
-    # write_body_stream is an alias for write_body_each if IO.copy_stream
+    # write_body_stream is an alias for write_body_each if copy_stream
     # isn't used or available.
     def write_body_stream(body)
-      IO.copy_stream(io = body_to_io(body), self)
+      COPY_STREAM.copy_stream(io = body_to_io(body), self)
       ensure
         close_if_private(io)
     end
-  else # ! IO.respond_to?(:copy_stream)
+  else # ! COPY_STREAM
     alias write_body_stream write_body_each
-  end  # ! IO.respond_to?(:copy_stream)
+  end  # ! COPY_STREAM
 
-  if IO.method_defined?(:trysendfile) || IO.respond_to?(:copy_stream)
+  if IO.method_defined?(:trysendfile) || COPY_STREAM
     HTTP_RANGE = 'HTTP_RANGE'
     Content_Range = 'Content-Range'.freeze
 
@@ -181,5 +182,5 @@ module Rainbows::Response
       end
     end
     include ToPath
-  end # IO.respond_to?(:copy_stream) || IO.method_defined?(:trysendfile)
+  end # COPY_STREAM || IO.method_defined?(:trysendfile)
 end