socket: allow exception-free nonblocking sendmsg/recvmsg

As documented before, exceptions are expensive and IO::Wait*able are too
common in socket applications to be the exceptional case.  Datagram
sockets deserve the same API which stream sockets are allowed with
read_nonblock and write_nonblock.

Note: this does not offer a performance advantage under optimal
conditions when both ends are equally matched in speed, but it it
does make debug output cleaner by avoiding exceptions whenever
the receiver slows down.

* ext/socket/ancdata.c (bsock_sendmsg_internal, bsock_recvmsg_internal):
  support "exception: false" kwarg
* ext/socket/init.c (rsock_s_recvfrom_nonblock):
  ditto
* ext/socket/init.c (rsock_s_recvfrom_nonblock): use rsock_opt_false_p
* ext/socket/socket.c (sock_connect_nonblock): ditto
* ext/socket/rubysocket.h (rsock_opt_false_p): new function
* ext/socket/basicsocket.c (bsock_recv_nonblock): update rdoc
* ext/socket/udpsocket.c (udp_recvfrom_nonblock): ditto
* test/socket/test_nonblock.rb: new tests

[ruby-core:69542] [Feature #11229]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@50910 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 44 insertions, 0 deletions

diff --git a/test/socket/test_nonblock.rb b/test/socket/test_nonblock.rb
index f0fba3af74..4e14c9355a 100644
--- a/test/socket/test_nonblock.rb
+++ b/test/socket/test_nonblock.rb
@@ -1,6 +1,7 @@
 begin
   require "socket"
   require "io/nonblock"
+  require "io/wait"
 rescue LoadError
 end
 
@@ -275,6 +276,17 @@ class TestSocketNonblock < Test::Unit::TestCase
     }
   end
 
+  def test_recvfrom_nonblock_no_exception
+    udp_pair do |s1, s2|
+      assert_equal :wait_readable, s1.recvfrom_nonblock(100, exception: false)
+      s2.send("aaa", 0, s1.getsockname)
+      assert s1.wait_readable
+      mesg, inet_addr = s1.recvfrom_nonblock(100, exception: false)
+      assert_equal(4, inet_addr.length)
+      assert_equal("aaa", mesg)
+    end
+  end
+
   if defined?(UNIXSocket) && defined?(Socket::SOCK_SEQPACKET)
     def test_sendmsg_nonblock_seqpacket
       buf = '*' * 8192
@@ -286,6 +298,27 @@ class TestSocketNonblock < Test::Unit::TestCase
     rescue NotImplementedError, Errno::ENOSYS, Errno::EPROTONOSUPPORT
       skip "UNIXSocket.pair(:SEQPACKET) not implemented on this platform: #{$!}"
     end
+
+    def test_sendmsg_nonblock_no_exception
+      buf = '*' * 128
+      UNIXSocket.pair(:SEQPACKET) do |s1, s2|
+        n = 0
+        Timeout.timeout(60) do
+          case rv = s1.sendmsg_nonblock(buf, exception: false)
+          when Integer
+            n += rv
+          when :wait_writable
+            break
+          else
+            flunk "unexpected return value: #{rv.inspect}"
+          end while true
+          assert_equal :wait_writable, rv
+          assert_operator n, :>, 0
+        end
+      end
+    rescue NotImplementedError, Errno::ENOSYS, Errno::EPROTONOSUPPORT
+      skip "UNIXSocket.pair(:SEQPACKET) not implemented on this platform: #{$!}"
+    end
   end
 
   def test_recvmsg_nonblock_error
@@ -297,6 +330,7 @@ class TestSocketNonblock < Test::Unit::TestCase
       rescue Errno::EWOULDBLOCK
         assert_kind_of(IO::WaitReadable, $!)
       end
+      assert_equal :wait_readable, s1.recvmsg_nonblock(11, exception: false)
     }
   end
 
@@ -310,6 +344,16 @@ class TestSocketNonblock < Test::Unit::TestCase
     }
   end
 
+  def test_recv_nonblock_no_exception
+    tcp_pair {|c, s|
+      assert_equal :wait_readable, c.recv_nonblock(11, exception: false)
+      s.write('HI')
+      assert c.wait_readable
+      assert_equal 'HI', c.recv_nonblock(11, exception: false)
+      assert_equal :wait_readable, c.recv_nonblock(11, exception: false)
+    }
+  end
+
   def test_connect_nonblock_error
     serv = TCPServer.new("127.0.0.1", 0)
     _, port, _, _ = serv.addr