(unless (member direction '(:input :output))
;; FIXME: should be TYPE-ERROR?
(error "Invalid direction ~S, must be either :INPUT or :OUTPUT" direction))
+ (unless (<= 0 fd (1- sb!unix:fd-setsize))
+ (error "Cannot add an FD handler for ~D: not under FD_SETSIZE limit." fd))
(let ((handler (make-handler direction fd function)))
(with-descriptor-handlers
(push handler *descriptor-handlers*))
(sb!unix:unix-fstat (handler-descriptor handler)))
(setf (handler-bogus handler) t)
(push handler bogus-handlers)))
- (restart-case (error "~S ~[have~;has a~:;have~] bad file descriptor~:P."
- bogus-handlers (length bogus-handlers))
- (remove-them ()
- :report "Remove bogus handlers."
- (with-descriptor-handlers
- (setf *descriptor-handlers*
- (delete-if #'handler-bogus *descriptor-handlers*))))
- (retry-them ()
- :report "Retry bogus handlers."
- (dolist (handler bogus-handlers)
- (setf (handler-bogus handler) nil)))
- (continue ()
- :report "Go on, leaving handlers marked as bogus.")))
+ (when bogus-handlers
+ (restart-case (error "~S ~[have~;has a~:;have~] bad file descriptor~:P."
+ bogus-handlers (length bogus-handlers))
+ (remove-them ()
+ :report "Remove bogus handlers."
+ (with-descriptor-handlers
+ (setf *descriptor-handlers*
+ (delete-if #'handler-bogus *descriptor-handlers*))))
+ (retry-them ()
+ :report "Retry bogus handlers."
+ (dolist (handler bogus-handlers)
+ (setf (handler-bogus handler) nil)))
+ (continue ()
+ :report "Go on, leaving handlers marked as bogus."))))
nil)
\f
;;;; SERVE-ALL-EVENTS, SERVE-EVENT, and friends
+;;; When a *periodic-polling-function* is defined the server will not
+;;; block for more than the maximum event timeout and will call the
+;;; polling function if it does time out.
+(declaim (type (or null symbol function) *periodic-polling-function*))
+(defvar *periodic-polling-function* nil
+ "Either NIL, or a designator for a function callable without any
+arguments. Called when the system has been waiting for input for
+longer then *PERIODIC-POLLING-PERIOD* seconds. Shared between all
+threads, unless locally bound. EXPERIMENTAL.")
+(declaim (real *periodic-polling-period*))
+(defvar *periodic-polling-period* 0
+ "A real number designating the number of seconds to wait for input
+at maximum, before calling the *PERIODIC-POLLING-FUNCTION* \(if any.)
+Shared between all threads, unless locally bound. EXPERIMENTAL.")
+
;;; Wait until FD is usable for DIRECTION. The timeout given to serve-event is
;;; recalculated each time through the loop so that WAIT-UNTIL-FD-USABLE will
;;; timeout at the correct time irrespective of how many events are handled in
;;; the meantime.
-(defun wait-until-fd-usable (fd direction &optional timeout)
+(defun wait-until-fd-usable (fd direction &optional timeout (serve-events t))
#!+sb-doc
"Wait until FD is usable for DIRECTION. DIRECTION should be either :INPUT or
:OUTPUT. TIMEOUT, if supplied, is the number of seconds to wait before giving
-up."
- (let (usable)
- (multiple-value-bind (to-sec to-usec stop-sec stop-usec signalp)
- (decode-timeout timeout)
- (declare (type (or integer null) to-sec to-usec))
- (with-fd-handler (fd direction (lambda (fd)
- (declare (ignore fd))
- (setf usable t)))
- (loop
- (sub-serve-event to-sec to-usec signalp)
- (when usable
- (return t))
- (when to-sec
- (multiple-value-bind (sec usec)
- (decode-internal-time (get-internal-real-time))
- (setf to-sec (- stop-sec sec))
- (cond ((> usec stop-usec)
- (decf to-sec)
- (setf to-usec (- (+ stop-usec 1000000) usec)))
- (t
- (setf to-usec (- stop-usec usec)))))
- (when (or (minusp to-sec) (minusp to-usec))
- (if signalp
- (signal-deadline)
- (return nil)))))))))
+up. Returns true once the FD is usable, NIL return indicates timeout.
+
+If SERVE-EVENTS is true (the default), events on other FDs are served while
+waiting."
+ (tagbody
+ :restart
+ (multiple-value-bind (to-sec to-usec stop-sec stop-usec signalp)
+ (decode-timeout timeout)
+ (declare (type (or integer null) to-sec to-usec))
+ (flet ((maybe-update-timeout ()
+ ;; If we return early, recompute the timeouts, possibly
+ ;; signaling the deadline or returning with NIL to caller.
+ (multiple-value-bind (sec usec)
+ (decode-internal-time (get-internal-real-time))
+ (setf to-sec (- stop-sec sec))
+ (cond ((> usec stop-usec)
+ (decf to-sec)
+ (setf to-usec (- (+ stop-usec 1000000) usec)))
+ (t
+ (setf to-usec (- stop-usec usec)))))
+ (when (or (minusp to-sec) (and (zerop to-sec) (not (plusp to-usec))))
+ (cond (signalp
+ (signal-deadline)
+ (go :restart))
+ (t
+ (return-from wait-until-fd-usable nil))))))
+ (if (and serve-events
+ ;; No timeout or non-zero timeout
+ (or (not to-sec)
+ (not (= 0 to-sec to-usec)))
+ ;; Something to do while we wait
+ (or *descriptor-handlers* *periodic-polling-function*))
+ ;; Loop around SUB-SERVE-EVENT till done.
+ (dx-let ((usable (list nil)))
+ (dx-flet ((usable! (fd)
+ (declare (ignore fd))
+ (setf (car usable) t)))
+ (with-fd-handler (fd direction #'usable!)
+ (loop
+ (sub-serve-event to-sec to-usec signalp)
+ (when (car usable)
+ (return-from wait-until-fd-usable t))
+ (when to-sec
+ (maybe-update-timeout))))))
+ ;; If we don't have to serve events, just poll on the single FD instead.
+ (loop for to-msec = (if (and to-sec to-usec)
+ (+ (* 1000 to-sec) (truncate to-usec 1000))
+ -1)
+ when (or #!+win32 (eq direction :output)
+ (sb!unix:unix-simple-poll fd direction to-msec))
+ do (return-from wait-until-fd-usable t)
+ else
+ do (when to-sec (maybe-update-timeout))))))))
\f
;;; Wait for up to timeout seconds for an event to happen. Make sure all
;;; pending events are processed before returning.
(declare (ignore stop-sec stop-usec))
(sub-serve-event to-sec to-usec signalp)))
-;;; Takes timeout broken into seconds and microseconds.
+;;; Takes timeout broken into seconds and microseconds, NIL timeout means
+;;; to wait as long as needed.
(defun sub-serve-event (to-sec to-usec deadlinep)
- ;; Next, wait for something to happen.
+ (or
+ (if *periodic-polling-function*
+ (multiple-value-bind (p-sec p-usec)
+ (decode-internal-time
+ (seconds-to-internal-time *periodic-polling-period*))
+ (if to-sec
+ (loop repeat (/ (+ to-sec (/ to-usec 1e6))
+ *periodic-polling-period*)
+ thereis (sub-sub-serve-event p-sec p-usec)
+ do (funcall *periodic-polling-function*))
+ (loop thereis (sub-sub-serve-event p-sec p-usec)
+ do (funcall *periodic-polling-function*))))
+ (sub-sub-serve-event to-sec to-usec))
+ (when deadlinep
+ (signal-deadline))))
+
+;;; Handles the work of the above, except for periodic polling. Returns
+;;; true if something of interest happened.
+(defun sub-sub-serve-event (to-sec to-usec)
(sb!alien:with-alien ((read-fds (sb!alien:struct sb!unix:fd-set))
(write-fds (sb!alien:struct sb!unix:fd-set)))
+ (sb!unix:fd-zero read-fds)
+ (sb!unix:fd-zero write-fds)
+ (let ((count 0))
+ (declare (type index count))
- (sb!unix:fd-zero read-fds)
- (sb!unix:fd-zero write-fds)
- (let ((count 0))
- (declare (type index count))
-
- ;; Initialize the fd-sets for UNIX-SELECT and return the active
- ;; descriptor count.
- (map-descriptor-handlers
- (lambda (handler)
- ;; FIXME: If HANDLER-ACTIVE ever is reinstanted, it needs
- ;; to be checked here in addition to HANDLER-BOGUS
- (unless (handler-bogus handler)
- (let ((fd (handler-descriptor handler)))
- (ecase (handler-direction handler)
- (:input (sb!unix:fd-set fd read-fds))
- (:output (sb!unix:fd-set fd write-fds)))
- (when (> fd count)
- (setf count fd))))))
- (incf count)
+ ;; Initialize the fd-sets for UNIX-SELECT and return the active
+ ;; descriptor count.
+ (map-descriptor-handlers
+ (lambda (handler)
+ ;; FIXME: If HANDLER-ACTIVE ever is reinstanted, it needs
+ ;; to be checked here in addition to HANDLER-BOGUS
+ (unless (handler-bogus handler)
+ (let ((fd (handler-descriptor handler)))
+ (ecase (handler-direction handler)
+ (:input (sb!unix:fd-set fd read-fds))
+ (:output (sb!unix:fd-set fd write-fds)))
+ (when (> fd count)
+ (setf count fd))))))
+ (incf count)
;; Next, wait for something to happen.
(multiple-value-bind (value err)
;; FIXME: Check for other errnos. Why do we return true
;; when interrupted?
#!-win32
- (if (eql err sb!unix:eintr)
- t
- (handler-descriptors-error))
+ (case err
+ (#.sb!unix:ebadf
+ (handler-descriptors-error))
+ ((#.sb!unix:eintr #.sb!unix:eagain)
+ t)
+ (otherwise
+ (with-simple-restart (continue "Ignore failure and continue.")
+ (simple-perror "Unix system call select() failed"
+ :errno err))))
#!+win32
(handler-descriptors-error))
((plusp value)
(ecase (handler-direction handler)
(:input (sb!unix:fd-isset fd read-fds))
(:output (sb!unix:fd-isset fd write-fds)))))))
- (funcall (handler-function handler)
- (handler-descriptor handler)))
- t)
- ((zerop value)
- (when deadlinep
- (signal-deadline))
- nil))))))
+ (with-simple-restart (remove-fd-handler "Remove ~S" handler)
+ (funcall (handler-function handler)
+ (handler-descriptor handler))
+ (go :next))
+ (remove-fd-handler handler)
+ :next)
+ t))))))
+