[Chicken-users] Proposed addition to tcp unit

[F. Wittenberger]

Hi all,

I wanted to control tcp connections from chicken, but handle the actual
traffic by an external program.

This appears not quite possible with the tcp unit as it stands.
tcp-accept starts reading from the accepted connection while my
connection handler starves.  (Or at worst they will share the traffic in
an unpredictable way.)

To cope with the situation I added "tcp-get-next-client" (which is
incidentally compatible with rscheme's "get-next-client", since that's
the code I'm porting).

Is this a general useful addition?  I'd appreciate if it would it make
it into chicken.  Will it?

(define (tcp-get-next-client tcpl)
  (##sys#check-structure tcpl 'tcp-listener)
  (let ((fd (##sys#slot tcpl 1))
        (tma (tcp-accept-timeout)))
    (let loop ()
      (if (eq? 1 (##net#select fd))
          (let ((fd (##net#accept fd #f #f)))
            (when (eq? -1 fd)
              (##sys#update-errno)
              (##sys#signal-hook 
               #:network-error 'tcp-accept (##sys#string-append "could not
accept from listener - " strerror) 
               tcpl) )
            (values fd (##net#getpeername fd)))
          (begin
            (when tma
              (##sys#thread-block-for-timeout! 
               ##sys#current-thread
               (fx+ (##sys#fudge 16) tma) ) )
            (##sys#thread-block-for-i/o! ##sys#current-thread fd #t)
            (yield)
            (when (##sys#slot ##sys#current-thread 13)
              (##sys#signal-hook
               #:network-error
               'tcp-accept
               "accept operation timed out" fd) )
            (loop) ) ) ) ) )

BTW: It works as expected.

/Jörg