Re: [gnugo-devel] socket support for Windows: patch

[Nando]

Hi,

Just barging in to make a small point in the discussion: it _is_ possible
to use Windows sockets with buffered i/o functions like fgets(). The
appended patch illustrates how it could be done.

I made a small GTP session connecting to a listening gnugo process with
telnet. I didn't test fancy things, but everything seemed ok (boardsize,
version, genmove, showboard, etc)

Caveats:
- it will work on NT/2K/XP/2K3, I'm less sure about Win9x/ME, but if the
  MS docs are correct (*cough*), it should.
- it will definitely _not_ work on WinCE : as I explained a couple days
  ago, read() in the VC++ CRT is based on the Win32 ReadFile() API, which
  doesn't accept sockets as file handles in WinCE (but does in Win32)

As a conclusion : I think it is possible to make a light patch that allows
Windows builds to use sockets. But it won't help even a bit for WinCE
platforms.

-- nando

PS: the patch below is meant for discussion, the small change to config.vc
    was intentionnally omitted.


Index: interface/main.c
===================================================================
RCS file: /cvsroot/gnugo/gnugo/interface/main.c,v
retrieving revision 1.109
diff -u -r1.109 main.c
--- interface/main.c    7 Dec 2004 04:50:02 -0000       1.109
+++ interface/main.c    17 Dec 2004 19:56:40 -0000
@@ -1686,12 +1686,40 @@
 
 #if ENABLE_SOCKET_SUPPORT
 
-
+#ifdef HAVE_VISUAL_C
+#include <fcntl.h>
+#include <winsock.h>
+#else
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
 #include <netdb.h>
+#endif
+
+#ifdef HAVE_VISUAL_C
+
+static void
+init_winsock(void)
+{
+  WORD wVersionRequested;
+  WSADATA wsaData;
+  int err;
+  int sock_opt = SO_SYNCHRONOUS_NONALERT;
+
+  wVersionRequested = MAKEWORD(1, 1); 
+  err = WSAStartup(wVersionRequested, &wsaData);
+  if (err != 0) {
+    fprintf(stderr, "WSAStartup failed\n");
+    exit(EXIT_FAILURE);
+  }
 
+/* Enable the use of sockets as filehandles
+ */
+  setsockopt(INVALID_SOCKET, SOL_SOCKET, SO_OPENTYPE, (char *)&sock_opt,
+            sizeof(sock_opt));
+}
+
+#endif
 
 static void
 socket_connect_to(const char *host_name, unsigned int port,
@@ -1702,6 +1730,12 @@
   struct hostent *host_data;
   char **address_pointer;
 
+#ifdef HAVE_VISUAL_C
+  int osfh;
+
+  init_winsock();
+#endif
+
   if (!host_name)
     host_name = "127.0.0.1";
 
@@ -1736,8 +1770,14 @@
     exit(EXIT_FAILURE);
   }
 
+#ifdef HAVE_VISUAL_C
+  osfh = _open_osfhandle(connection_socket, _O_TEXT);
+  *input_file  = fdopen(osfh, "r");
+  *output_file = fdopen(dup(osfh), "w");
+#else
   *input_file  = fdopen(connection_socket, "r");
   *output_file = fdopen(dup(connection_socket), "w");
+#endif
 }
 
 
@@ -1749,6 +1789,12 @@
   int listening_socket;
   int connection_socket;
 
+#ifdef HAVE_VISUAL_C
+  int osfh;
+
+  init_winsock();
+#endif
+
   if (host_name) {
     struct hostent *host_data;
 
@@ -1800,8 +1846,14 @@
 
   close(listening_socket);
 
+#ifdef HAVE_VISUAL_C
+  osfh = _open_osfhandle(connection_socket, _O_TEXT);
+  *input_file  = fdopen(osfh, "r");
+  *output_file = fdopen(dup(osfh), "w");
+#else
   *input_file  = fdopen(connection_socket, "r");
   *output_file = fdopen(dup(connection_socket), "w");
+#endif
 }