socket: avoid arg parsing in rsock_s_recvfrom_nonblock

* ext/socket/init.c (rsock_s_recvfrom_nonblock):
  avoid arg parsing with C API
  [ruby-core:71439] [Feature #11339]
* ext/socket/basicsocket.c (bsock_recv_nonblock):
  adjust for above change, make private
* ext/socket/socket.c (sock_recvfrom_nonblock): ditto
* ext/socket/udpsocket.c (udp_recvfrom_nonblock): ditto
* ext/socket/lib/socket.rb (BasicSocket#recv_nonblock):
  new wrapper for private method, move RDoc
  (Socket#recvfrom_nonblock): ditto
  (UDPSocket#recvfrom_nonblock): ditto

Note, not adding bm_recv_nonblock.rb to benchmark/ directory
since it is non-portable.  It is only in this commit message.

Benchmark results + code
target 0: a (ruby 2.3.0dev (2015-11-12 trunk 52540) [x86_64-linux])
target 1: b (ruby 2.3.0dev (2015-11-12 avoid-kwarg-capi 52540) [x86_64-linux]

-----------------------------------------------------------
recv_nonblock

require 'socket'
nr = 1000000
msg = 'hello world'
buf = ''
size = msg.bytesize
UNIXSocket.pair(:SEQPACKET) do |a, b|
  nr.times do
    a.sendmsg(msg)
    b.recv_nonblock(size, 0, buf, exception: false)
  end
end

-----------------------------------------------------------
raw data:

[["recv_nonblock",
  [[1.83511221408844,
    1.8703329525887966,
    1.8448856547474861,
    1.859263762831688,
    1.8331583738327026],
   [1.5637447573244572,
    1.4062932096421719,
    1.4247371144592762,
    1.4108827747404575,
    1.4802536629140377]]]]

Elapsed time: 16.530452496 (sec)
-----------------------------------------------------------
benchmark results:
minimum results in each 5 measurements.
Execution time (sec)
name          a       b
recv_nonblock   1.833   1.406

Speedup ratio: compare with the result of `a' (greater is better)
name          b
recv_nonblock   1.304

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52598 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 7 insertions, 65 deletions

diff --git a/ext/socket/socket.c b/ext/socket/socket.c
index 779398c88d..1a3320dbe5 100644
--- a/ext/socket/socket.c
+++ b/ext/socket/socket.c
@@ -813,72 +813,11 @@ sock_recvfrom(int argc, VALUE *argv, VALUE sock)
     return rsock_s_recvfrom(sock, argc, argv, RECV_SOCKET);
 }
 
-/*
- * call-seq:
- *   socket.recvfrom_nonblock(maxlen) => [mesg, sender_addrinfo]
- *   socket.recvfrom_nonblock(maxlen, flags) => [mesg, sender_addrinfo]
- *
- * Receives up to _maxlen_ bytes from +socket+ using recvfrom(2) after
- * O_NONBLOCK is set for the underlying file descriptor.
- * _flags_ is zero or more of the +MSG_+ options.
- * The first element of the results, _mesg_, is the data received.
- * The second element, _sender_addrinfo_, contains protocol-specific address
- * information of the sender.
- *
- * When recvfrom(2) returns 0, Socket#recvfrom_nonblock returns
- * an empty string as data.
- * The meaning depends on the socket: EOF on TCP, empty packet on UDP, etc.
- *
- * === Parameters
- * * +maxlen+ - the maximum number of bytes to receive from the socket
- * * +flags+ - zero or more of the +MSG_+ options
- *
- * === Example
- *   # In one file, start this first
- *   require 'socket'
- *   include Socket::Constants
- *   socket = Socket.new(AF_INET, SOCK_STREAM, 0)
- *   sockaddr = Socket.sockaddr_in(2200, 'localhost')
- *   socket.bind(sockaddr)
- *   socket.listen(5)
- *   client, client_addrinfo = socket.accept
- *   begin # emulate blocking recvfrom
- *     pair = client.recvfrom_nonblock(20)
- *   rescue IO::WaitReadable
- *     IO.select([client])
- *     retry
- *   end
- *   data = pair[0].chomp
- *   puts "I only received 20 bytes '#{data}'"
- *   sleep 1
- *   socket.close
- *
- *   # In another file, start this second
- *   require 'socket'
- *   include Socket::Constants
- *   socket = Socket.new(AF_INET, SOCK_STREAM, 0)
- *   sockaddr = Socket.sockaddr_in(2200, 'localhost')
- *   socket.connect(sockaddr)
- *   socket.puts "Watch this get cut short!"
- *   socket.close
- *
- * Refer to Socket#recvfrom for the exceptions that may be thrown if the call
- * to _recvfrom_nonblock_ fails.
- *
- * Socket#recvfrom_nonblock may raise any error corresponding to recvfrom(2) failure,
- * including Errno::EWOULDBLOCK.
- *
- * If the exception is Errno::EWOULDBLOCK or Errno::EAGAIN,
- * it is extended by IO::WaitReadable.
- * So IO::WaitReadable can be used to rescue the exceptions for retrying recvfrom_nonblock.
- *
- * === See
- * * Socket#recvfrom
- */
+/* :nodoc: */
 static VALUE
-sock_recvfrom_nonblock(int argc, VALUE *argv, VALUE sock)
+sock_recvfrom_nonblock(VALUE sock, VALUE len, VALUE flg, VALUE str, VALUE ex)
 {
-    return rsock_s_recvfrom_nonblock(sock, argc, argv, RECV_SOCKET);
+    return rsock_s_recvfrom_nonblock(sock, len, flg, str, ex, RECV_SOCKET);
 }
 
 /*
@@ -2182,7 +2121,10 @@ Init_socket(void)
     rb_define_method(rb_cSocket, "sysaccept", sock_sysaccept, 0);
 
     rb_define_method(rb_cSocket, "recvfrom", sock_recvfrom, -1);
-    rb_define_method(rb_cSocket, "recvfrom_nonblock", sock_recvfrom_nonblock, -1);
+
+    /* for ext/socket/lib/socket.rb use only: */
+    rb_define_private_method(rb_cSocket,
+			     "__recvfrom_nonblock", sock_recvfrom_nonblock, 4);
 
     rb_define_singleton_method(rb_cSocket, "socketpair", rsock_sock_s_socketpair, -1);
     rb_define_singleton_method(rb_cSocket, "pair", rsock_sock_s_socketpair, -1);