stdlib: use IO#wait_*able instead of IO.select when possible

In case a process encounters high-numbered FDs, this allows
consistent performance on systems with ppoll support.
[ruby-core:35572]

* ext/socket/lib/socket.rb (connect_nonblock): use IO#wait_writable
* lib/drb/drb.rb (DRB::DRbTCPSocket#alive?): use IO#wait_readable
* lib/webrick/httpserver.rb (run): ditto
* lib/resolv.rb (request): ditto for single socket case
  [ruby-core:68943] [Feature #11081]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@50432 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,11 @@
+Thu May  7 05:14:39 2015  Eric Wong  <e@80x24.org>
+
+	* ext/socket/lib/socket.rb (connect_nonblock): use IO#wait_writable
+	* lib/drb/drb.rb (DRB::DRbTCPSocket#alive?): use IO#wait_readable
+	* lib/webrick/httpserver.rb (run): ditto
+	* lib/resolv.rb (request): ditto for single socket case
+	  [ruby-core:68943] [Feature #11081]
+
 Wed May  6 22:49:54 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* vm_eval.c (rb_method_call_status): undefined refined method is

ext/socket/lib/socket.rb

@@ -1,4 +1,5 @@
 require 'socket.so'
+require 'io/wait'
 
 class Addrinfo
   # creates an Addrinfo object from the arguments.
@@ -54,9 +55,8 @@ class Addrinfo
         when 0 # success or EISCONN, other errors raise
           break
         when :wait_writable
-          if !IO.select(nil, [sock], nil, timeout)
+          sock.wait_writable(timeout) or
             raise Errno::ETIMEDOUT, 'user specified timeout'
-          end
         end while true
       else
         sock.connect(self)

lib/drb/drb.rb

@@ -48,6 +48,7 @@
 require 'socket'
 require 'thread'
 require 'fcntl'
+require 'io/wait'
 require 'drb/eq'
 
 #
@@ -1003,7 +1004,7 @@ module DRb
     # Check to see if this connection is alive.
     def alive?
       return false unless @socket
-      if IO.select([@socket], nil, nil, 0)
+      if @socket.to_io.wait_readable(0)
         close
         return false
       end

lib/resolv.rb

@@ -1,6 +1,7 @@
 require 'socket'
 require 'timeout'
 require 'thread'
+require 'io/wait'
 
 begin
   require 'securerandom'
@@ -680,7 +681,11 @@ class Resolv
           if timeout <= 0
             raise ResolvTimeout
           end
+          if @socks.size == 1
+            select_result = @socks[0].wait_readable(timeout) ? [ @socks ] : nil
+          else
             select_result = IO.select(@socks, nil, nil, timeout)
+          end
           if !select_result
             after_select = Time.now
             next if after_select < timelimit

lib/webrick/httpserver.rb

@@ -8,6 +8,7 @@
 #
 # $IPR: httpserver.rb,v 1.63 2002/10/01 17:16:32 gotoyuzo Exp $
 
+require 'io/wait'
 require 'webrick/server'
 require 'webrick/httputils'
 require 'webrick/httpstatus'
@@ -72,7 +73,7 @@ module WEBrick
         begin
           timeout = @config[:RequestTimeout]
           while timeout > 0
-            break if IO.select([sock], nil, nil, 0.5)
+            break if sock.to_io.wait_readable(0.5)
             break if @status != :Running
             timeout -= 0.5
           end