[ruby-core:37192] rb_w32_add_socket / rb_w32_remove_socket

Hello,

There are many gems which attempt to make use of Windows sockets
created by external libraries (libpq, libmysqlclient, libcurl, etc).
Currently, they are all broken. This is impossible on Ruby 1.9, and on
Ruby 1.8 it required a significant hack which I submitted to several
projects only this year.

First, I should make it clear that I think the correct way to fix this
is to remove the use of _open_osfhandle *entirely* from win32/win32.c,
as I suggested here: http://www.ruby-forum.com/topic/869239 However
this is becoming increasingly more time consuming as  Ruby 1.9 adds to
the complexity of the win32 layer, and it seems unlikely that a 1.8
release with such a tremendously large patch would ever occur.

So, attached are two very tiny patches for new functions which will
allow gem authors to use externally created sockets. Their usage is as
follows:

int fd = libwhatever_get_socket();
#ifdef _WIN32
  ruby_fd = rb_w32_add_socket(fd, 0);
#else
  ruby_fd = fd;
#endif

... do stuff with the ruby_fd as you would on other platforms ...

#ifdef _WIN32
  rb_w32_remove_socket(ruby_fd);
#endif

libwhatever_close_socket(fd);

In a nutshell; you pass the SOCKET given to you by the external
library to ruby and it gives you a CRT fd you can use with ruby
functions. When you're done, you pass that CRT fd to ruby to remove
it, and then close the SOCKET however the library normally does.

If the ifdefs are not preferred, rb_add_socket / rb_remove_socket
could be added as no-ops on non-win32 platforms, however I should
stress that making this a permanent fixture of the API is probably a
mistake, and the ruby win32 code should be rewritten to use
HANDLEs/SOCKETs instead of CRT fds.

Thoughts?

-Greg