accept_nonblock supports "exception: false"

This is analogous to functionality found in IO#read_nonblock and
IO#wait_nonblock.  Raising exceptions for common failures on
non-blocking servers is expensive and makes $DEBUG too noisy.

Benchmark results:
                                    user     system      total        real
default                         2.790000   0.870000   3.660000 (  3.671597)
exception: false                1.120000   0.800000   1.920000 (  1.922032)
exception: false (cached arg)   0.820000   0.770000   1.590000 (  1.589267)
--------------------- benchmark script ------------------------
require 'socket'
require 'benchmark'
require 'tmpdir'
nr = 1000000
Dir.mktmpdir('nb_bench') do |path|
  sock_path = "#{path}/test.sock"
  s = UNIXServer.new(sock_path)
  Benchmark.bmbm do |x|
    x.report("default") do
      nr.times do
        begin
          s.accept_nonblock
        rescue IO::WaitReadable
        end
      end
    end
    x.report("exception: false") do
      nr.times do
        begin
          s.accept_nonblock(exception: false)
        rescue IO::WaitReadable
          abort "should not raise"
        end
      end
    end
    x.report("exception: false (cached arg)") do
      arg = { exception: false }
      nr.times do
        begin
          s.accept_nonblock(arg)
        rescue IO::WaitReadable
          abort "should not raise"
        end
      end
    end
  end
end

* ext/socket/init.c (rsock_s_accept_nonblock):
  support exception: false
  [ruby-core:66385] [Feature #10532]
* ext/socket/init.c (rsock_init_socket_init): define new symbols
* ext/socket/rubysocket.h: adjust prototype
* ext/socket/socket.c (sock_accept_nonblock): support exception: false
* ext/openssl/ossl_ssl.c (ossl_ssl_accept_nonblock): ditto
* ext/socket/socket.c (Init_socket): adjust accept_nonblock definition
* ext/openssl/ossl_ssl.c (Init_ossl_ssl): ditto
* ext/socket/tcpserver.c (rsock_init_tcpserver): ditto
* ext/socket/unixserver.c (rsock_init_unixserver): ditto
* ext/socket/tcpserver.c (tcp_accept_nonblock): adjust
  rsock_s_accept_nonblock call
* ext/socket/unixserver.c (unix_accept_nonblock): ditto
* ext/openssl/ossl_ssl.c (ossl_start_ssl): support no_exception
* ext/openssl/ossl_ssl.c (ossl_ssl_connect): adjust ossl_start_ssl call
* ext/openssl/ossl_ssl.c (ossl_ssl_connect_nonblock): ditto
* ext/openssl/ossl_ssl.c (ossl_ssl_accept): ditto
* test/socket/test_nonblock.rb (test_accept_nonblock): test for
  "exception :false"
* test/socket/test_tcp.rb (test_accept_nonblock): new test
* test/socket/test_unix.rb (test_accept_nonblock): ditto
* test/openssl/test_pair.rb (test_accept_nonblock_no_exception): ditto

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49948 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 12 insertions, 4 deletions

diff --git a/ext/socket/socket.c b/ext/socket/socket.c
index eeee571036..bb18409489 100644
--- a/ext/socket/socket.c
+++ b/ext/socket/socket.c
@@ -894,7 +894,7 @@ sock_accept(VALUE sock)
 
 /*
  * call-seq:
- *   socket.accept_nonblock => [client_socket, client_addrinfo]
+ *   socket.accept_nonblock([options]) => [client_socket, client_addrinfo]
  *
  * Accepts an incoming connection using accept(2) after
  * O_NONBLOCK is set for the underlying file descriptor.
@@ -940,19 +940,27 @@ sock_accept(VALUE sock)
  * it is extended by IO::WaitReadable.
  * So IO::WaitReadable can be used to rescue the exceptions for retrying accept_nonblock.
  *
+ * By specifying `exception: false`, the options hash allows you to indicate
+ * that accept_nonblock should not raise an IO::WaitReadable exception, but
+ * return the symbol :wait_readable instead.
+ *
  * === See
  * * Socket#accept
  */
 static VALUE
-sock_accept_nonblock(VALUE sock)
+sock_accept_nonblock(int argc, VALUE *argv, VALUE sock)
 {
     rb_io_t *fptr;
     VALUE sock2;
     union_sockaddr buf;
+    struct sockaddr *addr = &buf.addr;
     socklen_t len = (socklen_t)sizeof buf;
 
     GetOpenFile(sock, fptr);
-    sock2 = rsock_s_accept_nonblock(rb_cSocket, fptr, &buf.addr, &len);
+    sock2 = rsock_s_accept_nonblock(argc, argv, rb_cSocket, fptr, addr, &len);
+
+    if (SYMBOL_P(sock2)) /* :wait_readable */
+	return sock2;
     return rb_assoc_new(sock2, rsock_io_socket_addrinfo(sock2, &buf.addr, len));
 }
 
@@ -2154,7 +2162,7 @@ Init_socket(void)
     rb_define_method(rb_cSocket, "bind", sock_bind, 1);
     rb_define_method(rb_cSocket, "listen", rsock_sock_listen, 1);
     rb_define_method(rb_cSocket, "accept", sock_accept, 0);
-    rb_define_method(rb_cSocket, "accept_nonblock", sock_accept_nonblock, 0);
+    rb_define_method(rb_cSocket, "accept_nonblock", sock_accept_nonblock, -1);
     rb_define_method(rb_cSocket, "sysaccept", sock_sysaccept, 0);
 
     rb_define_method(rb_cSocket, "recvfrom", sock_recvfrom, -1);