(defmacro with-deadline ((&key seconds override)
&body body)
- "Arranges for a TIMEOUT condition to be signalled if an operation respecting
-deadlines occurs either after the deadline has passed, or would take longer
-than the time left to complete.
+ "Arranges for a TIMEOUT condition to be signalled if an operation
+respecting deadlines occurs either after the deadline has passed, or
+would take longer than the time left to complete.
-Currently only blocking IO operations, GET-MUTEX, and CONDITION-WAIT respect
-deadlines, but this includes their implicit uses inside SBCL itself.
+Currently only blocking IO operations, GET-MUTEX, and CONDITION-WAIT
+respect deadlines, but this includes their implicit uses inside SBCL
+itself.
+
+Unless OVERRIDE is true, existing deadlines can only be restricted,
+not extended. Deadlines are per thread: children are unaffected by
+their parent's deadlines.
Experimental."
(with-unique-names (deadline-seconds deadline)
#!+sb-doc
"Signals a timeout condition while inhibiting further timeouts due to
deadlines while the condition is being handled."
- (let ((*deadline* nil))
- (apply #'error datum arguments)))
+ ;; FIXME: Maybe we should make ERROR do WITH-INTERRUPTS instead of
+ ;; putting it all over the place (now that we have ALLOW-WITH-INTERRUPTS.)
+ (with-interrupts
+ ;; Don't signal a deadline while handling a non-deadline timeout.
+ (let ((*deadline* nil))
+ (apply #'error datum arguments))))
(defun signal-deadline ()
#!+sb-doc
- "Signal a DEADLINE-TIMEOUT condition. Implementors of blocking functions
-are responsible for calling this when a deadline is reached."
- (signal-timeout 'deadline-timeout :seconds *deadline-seconds*))
+ "Signal a DEADLINE-TIMEOUT condition, and associate a DEFER-DEADLINE
+restart with it. Implementors of blocking functions are responsible
+for calling this when a deadline is reached."
+ ;; Make sure we don't signal the same deadline twice. LET is not good
+ ;; enough: we might catch the same deadline again while unwinding.
+ (when *deadline*
+ (setf *deadline* nil))
+ (with-interrupts
+ (restart-case
+ (error 'deadline-timeout :seconds *deadline-seconds*)
+ (defer-deadline (&optional (seconds *deadline-seconds*))
+ :report "Defer the deadline for SECONDS more."
+ (let* ((new-deadline-seconds (coerce seconds 'single-float))
+ (new-deadline (+ (seconds-to-internal-time new-deadline-seconds)
+ (get-internal-real-time))))
+ (setf *deadline* new-deadline
+ *deadline-seconds* new-deadline-seconds)))))
+ nil)
+
+(defun defer-deadline (seconds &optional condition)
+ "Find the DEFER-DEADLINE restart associated with CONDITION, and
+calls it with SECONDS as argument (deferring the deadline by that many
+seconds.) Continues from the indicated restart, or returns NIL if the
+restart is not found."
+ (try-restart 'defer-deadline condition seconds))
;;; Returns TIMEOUT-SEC, TIMEOUT-USEC, DEADLINE-SEC, DEADLINE-USEC, SIGNALP
;;;
If SECONDS is null and there is no global timeout all returned values will be
null. If a global deadline has already passed when DECODE-TIMEOUT is called,
it will signal a timeout condition."
- (let* ((timeout (when seconds (seconds-to-internal-time seconds)))
- (now (get-internal-real-time))
- (deadline *deadline*)
- (deadline-timeout
- (when deadline
- (let ((time-left (- deadline now)))
- (if (plusp time-left)
- time-left
- (signal-deadline))))))
- (multiple-value-bind (final-timeout final-deadline signalp)
- ;; Use either *DEADLINE* or TIMEOUT to produce both a timeout
- ;; and deadline in internal-time units
- (cond ((and deadline timeout)
- (if (< timeout deadline-timeout)
- (values timeout (+ timeout now) nil)
- (values deadline-timeout deadline t)))
- (deadline
- (values deadline-timeout deadline t))
- (timeout
- (values timeout (+ timeout now) nil))
- (t
- (values nil nil nil)))
- (if final-timeout
- (multiple-value-bind (to-sec to-usec)
- (decode-internal-time final-timeout)
- (multiple-value-bind (stop-sec stop-usec)
- (decode-internal-time final-deadline)
- (values to-sec to-usec stop-sec stop-usec signalp)))
- (values nil nil nil nil nil)))))
+ (tagbody
+ :restart
+ (let* ((timeout (when seconds (seconds-to-internal-time seconds)))
+ (now (get-internal-real-time))
+ (deadline *deadline*)
+ (deadline-timeout
+ (when deadline
+ (let ((time-left (- deadline now)))
+ (if (plusp time-left)
+ time-left
+ (progn
+ (signal-deadline)
+ (go :restart)))))))
+ (return-from decode-timeout
+ (multiple-value-bind (final-timeout final-deadline signalp)
+ ;; Use either *DEADLINE* or TIMEOUT to produce both a timeout
+ ;; and deadline in internal-time units
+ (cond ((and deadline timeout)
+ (if (< timeout deadline-timeout)
+ (values timeout (+ timeout now) nil)
+ (values deadline-timeout deadline t)))
+ (deadline
+ (values deadline-timeout deadline t))
+ (timeout
+ (values timeout (+ timeout now) nil))
+ (t
+ (values nil nil nil)))
+ (if final-timeout
+ (multiple-value-bind (to-sec to-usec)
+ (decode-internal-time final-timeout)
+ (multiple-value-bind (stop-sec stop-usec)
+ (decode-internal-time final-deadline)
+ (values to-sec to-usec stop-sec stop-usec signalp)))
+ (values nil nil nil nil nil)))))))
+
projects / sbcl.git / blobdiff