socket (bsock_recvmsg_internal): avoid arg parsing

* ext/socket/ancdata.c (bsock_recvmsg_internal): avoid arg parsing
  (rsock_bsock_recvmsg): adjust for above change
  (rsock_bsock_recvmsg_nonblock): ditto
  [ruby-core:71439] [Feature #11339]
* ext/socket/rubysocket.h: adjust prototypes for above
* ext/socket/basicsocket.c (rsock_init_basicsocket):
  adjust private methods
* ext/socket/lib/socket.rb (BasicSocket#recvmsg): wrapper method
  (BasicSocket#recvmsg_nonblock): ditto

target 0: a (ruby 2.3.0dev (2015-11-12 trunk 52550) [x86_64-linux])
target 1: b (ruby 2.3.0dev (2015-11-12 avoid-kwarg-capi 52550) [x86_64-linux]

-----------------------------------------------------------
recvmsg_nonblock

require 'socket'
nr = 1_000_000
i = 0
msg = '.'
buf = '.'
begin
  r, w = UNIXSocket.pair(:SEQPACKET)
  while i < nr
    i += 1
    w.sendmsg(msg)
    r.recvmsg_nonblock(1, exception: false)
  end
ensure
  r.close
  w.close
end

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

[["recvmsg_nonblock",
  [[3.721687912940979,
    3.6072621569037437,
    3.580637402832508,
    3.614185404032469,
    3.6029579415917397],
   [2.4694008752703667,
    2.4908322244882584,
    2.5051278844475746,
    2.5037173740565777,
    2.548359278589487]]]]

Elapsed time: 30.646087052 (sec)
-----------------------------------------------------------
benchmark results:
minimum results in each 5 measurements.
Execution time (sec)
name             a       b
recvmsg_nonblock   3.581   2.469

Speedup ratio: compare with the result of `a' (greater is better)
name             b
recvmsg_nonblock   1.450

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52602 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 71 insertions, 0 deletions

diff --git a/ext/socket/lib/socket.rb b/ext/socket/lib/socket.rb
index fed1d43e34..9e85318c1b 100644
--- a/ext/socket/lib/socket.rb
+++ b/ext/socket/lib/socket.rb
@@ -324,6 +324,77 @@ class BasicSocket < IO
   def recv_nonblock(len, flag = 0, str = nil, exception: true)
     __recv_nonblock(len, flag, str, exception)
   end
+
+  # call-seq:
+  #    basicsocket.recvmsg(maxmesglen=nil, flags=0, maxcontrollen=nil, opts={}) => [mesg, sender_addrinfo, rflags, *controls]
+  #
+  # recvmsg receives a message using recvmsg(2) system call in blocking manner.
+  #
+  # _maxmesglen_ is the maximum length of mesg to receive.
+  #
+  # _flags_ is bitwise OR of MSG_* constants such as Socket::MSG_PEEK.
+  #
+  # _maxcontrollen_ is the maximum length of controls (ancillary data) to receive.
+  #
+  # _opts_ is option hash.
+  # Currently :scm_rights=>bool is the only option.
+  #
+  # :scm_rights option specifies that application expects SCM_RIGHTS control message.
+  # If the value is nil or false, application don't expects SCM_RIGHTS control message.
+  # In this case, recvmsg closes the passed file descriptors immediately.
+  # This is the default behavior.
+  #
+  # If :scm_rights value is neither nil nor false, application expects SCM_RIGHTS control message.
+  # In this case, recvmsg creates IO objects for each file descriptors for
+  # Socket::AncillaryData#unix_rights method.
+  #
+  # The return value is 4-elements array.
+  #
+  # _mesg_ is a string of the received message.
+  #
+  # _sender_addrinfo_ is a sender socket address for connection-less socket.
+  # It is an Addrinfo object.
+  # For connection-oriented socket such as TCP, sender_addrinfo is platform dependent.
+  #
+  # _rflags_ is a flags on the received message which is bitwise OR of MSG_* constants such as Socket::MSG_TRUNC.
+  # It will be nil if the system uses 4.3BSD style old recvmsg system call.
+  #
+  # _controls_ is ancillary data which is an array of Socket::AncillaryData objects such as:
+  #
+  #   #<Socket::AncillaryData: AF_UNIX SOCKET RIGHTS 7>
+  #
+  # _maxmesglen_ and _maxcontrollen_ can be nil.
+  # In that case, the buffer will be grown until the message is not truncated.
+  # Internally, MSG_PEEK is used and MSG_TRUNC/MSG_CTRUNC are checked.
+  #
+  # recvmsg can be used to implement recv_io as follows:
+  #
+  #   mesg, sender_sockaddr, rflags, *controls = sock.recvmsg(:scm_rights=>true)
+  #   controls.each {|ancdata|
+  #     if ancdata.cmsg_is?(:SOCKET, :RIGHTS)
+  #       return ancdata.unix_rights[0]
+  #     end
+  #   }
+  def recvmsg(dlen = 4096, flags = 0, clen = 4096, scm_rights: false)
+    __recvmsg(dlen, flags, clen, scm_rights)
+  end
+
+  # call-seq:
+  #    basicsocket.recvmsg_nonblock(maxdatalen=nil, flags=0, maxcontrollen=nil, opts={}) => [data, sender_addrinfo, rflags, *controls]
+  #
+  # recvmsg receives a message using recvmsg(2) system call in non-blocking manner.
+  #
+  # It is similar to BasicSocket#recvmsg
+  # but non-blocking flag is set before the system call
+  # and it doesn't retry the system call.
+  #
+  # By specifying `exception: false`, the _opts_ hash allows you to indicate
+  # that recvmsg_nonblock should not raise an IO::WaitWritable exception, but
+  # return the symbol :wait_writable instead.
+  def recvmsg_nonblock(dlen = 4096, flags = 0, clen = 4096,
+                       scm_rights: false, exception: true)
+    __recvmsg_nonblock(dlen, flags, clen, scm_rights, exception)
+  end
 end
 
 class Socket < BasicSocket