[PATCH] http_request: support proposed Raindrops::TCP states on non-Linux

[Eric Wong <e@80x24.org>]

raindrops 0.18+ will have Raindrops::TCP state hash for portable
mapping of TCP states to their respective numeric values.  This
was necessary because TCP state numbers (and even their names)
differ between FreeBSD and Linux (and possibly other OSes).

Favor using the Raindrops::TCP state hash if available, but
fall back to the hard-coded values since older versions of
raindrops did not support TCP_INFO on non-Linux systems.
---
 lib/unicorn/http_request.rb | 36 ++++++++++++++++++++++++++++--------
 1 file changed, 28 insertions(+), 8 deletions(-)

diff --git a/lib/unicorn/http_request.rb b/lib/unicorn/http_request.rb
index 9010007..46b8dec 100644
--- a/lib/unicorn/http_request.rb
+++ b/lib/unicorn/http_request.rb
@@ -118,14 +118,34 @@ def check_client_connection(socket) # :nodoc:
       end
     end
 
-    def closed_state?(state) # :nodoc:
-      case state
-      when 1 # ESTABLISHED
-        false
-      when 8, 6, 7, 9, 11 # CLOSE_WAIT, TIME_WAIT, CLOSE, LAST_ACK, CLOSING
-        true
-      else
-        false
+    if defined?(Raindrops::TCP)
+      # raindrops 0.18.0+ supports FreeBSD + Linux using the same names
+      # Evaluate these hash lookups at load time so we can
+      # generate an opt_case_dispatch instruction
+      eval <<-EOS
+      def closed_state?(state) # :nodoc:
+        case state
+        when #{Raindrops::TCP[:ESTABLISHED]}
+          false
+        when #{Raindrops::TCP.values_at(
+              :CLOSE_WAIT, :TIME_WAIT, :CLOSE, :LAST_ACK, :CLOSING).join(',')}
+          true
+        else
+          false
+        end
+      end
+      EOS
+    else
+      # raindrops before 0.18 only supported TCP_INFO under Linux
+      def closed_state?(state) # :nodoc:
+        case state
+        when 1 # ESTABLISHED
+          false
+        when 8, 6, 7, 9, 11 # CLOSE_WAIT, TIME_WAIT, CLOSE, LAST_ACK, CLOSING
+          true
+        else
+          false
+        end
       end
     end
   else
-- 
EW