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, 16 insertions, 2 deletions

diff --git a/ext/socket/init.c b/ext/socket/init.c
index c3f33964a8..b94b25098c 100644
--- a/ext/socket/init.c
+++ b/ext/socket/init.c
@@ -29,6 +29,7 @@ VALUE rb_cSOCKSSocket;
 #endif
 
 int rsock_do_not_reverse_lookup = 1;
+static VALUE sym_exception, sym_wait_readable;
 
 void
 rsock_raise_socket_error(const char *reason, int error)
@@ -505,11 +506,18 @@ cloexec_accept(int socket, struct sockaddr *address, socklen_t *address_len)
     return ret;
 }
 
-
 VALUE
-rsock_s_accept_nonblock(VALUE klass, rb_io_t *fptr, struct sockaddr *sockaddr, socklen_t *len)
+rsock_s_accept_nonblock(int argc, VALUE *argv, VALUE klass, rb_io_t *fptr,
+			struct sockaddr *sockaddr, socklen_t *len)
 {
     int fd2;
+    int ex = 1;
+    VALUE opts = Qnil;
+
+    rb_scan_args(argc, argv, "0:", &opts);
+
+    if (!NIL_P(opts) && Qfalse == rb_hash_aref(opts, sym_exception))
+	ex = 0;
 
     rb_secure(3);
     rb_io_set_nonblock(fptr);
@@ -524,6 +532,8 @@ rsock_s_accept_nonblock(VALUE klass, rb_io_t *fptr, struct sockaddr *sockaddr, s
 #if defined EPROTO
 	  case EPROTO:
 #endif
+            if (!ex)
+		return sym_wait_readable;
             rb_readwrite_sys_fail(RB_IO_WAIT_READABLE, "accept(2) would block");
 	}
         rb_sys_fail("accept(2)");
@@ -612,4 +622,8 @@ rsock_init_socket_init(void)
     rsock_init_addrinfo();
     rsock_init_sockifaddr();
     rsock_init_socket_constants();
+
+#undef rb_intern
+    sym_exception = ID2SYM(rb_intern("exception"));
+    sym_wait_readable = ID2SYM(rb_intern("wait_readable"));
 }