switch from IO#sendfile_nonblock to IO#trysendfile

IO#trysendfile does not raise exceptions for common EAGAIN
errors, making it far less expensive to use with the following
concurrency models:

* Coolio
* CoolioFiberSpawn
* Revactor
* FiberSpawn
* FiberPool

This requires the new sendfile 1.1.0 RubyGem and removes support
for the sendfile 1.0.0.  All sendfile users must upgrade or be
left without sendfile(2) support.  IO#sendfile behaves the same
if you're using a multi-threaded concurrency option, but we
don't detect nor use it unless IO#trysendfile exists.

1 files changed, 10 insertions, 9 deletions

diff --git a/lib/rainbows/fiber/body.rb b/lib/rainbows/fiber/body.rb
index 872b1df..5b2c74b 100644
--- a/lib/rainbows/fiber/body.rb
+++ b/lib/rainbows/fiber/body.rb
@@ -5,19 +5,20 @@
 # this is meant to be included _after_ Rainbows::Response::Body
 module Rainbows::Fiber::Body # :nodoc:
 
-  # the sendfile 1.0.0+ gem includes IO#sendfile_nonblock
-  if IO.method_defined?(:sendfile_nonblock)
+  # the sendfile 1.1.0+ gem includes IO#trysendfile
+  if IO.method_defined?(:trysendfile)
     def write_body_file(body, range)
       sock, n, body = to_io, nil, body_to_io(body)
       offset, count = range ? range : [ 0, body.stat.size ]
-      begin
-        offset += (n = sock.sendfile_nonblock(body, offset, count))
-      rescue Errno::EAGAIN
+      case n = sock.trysendfile(body, offset, count)
+      when Integer
+        offset += n
+        return if 0 == (count -= n)
+      when :wait_writable
         kgio_wait_writable
-        retry
-      rescue EOFError
-        break
-      end while (count -= n) > 0
+      else # nil
+        return
+      end while true
       ensure
         close_if_private(body)
     end