(define-module (8sync agenda)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-9)
- #:use-module (srfi srfi-9 gnu)
#:use-module (ice-9 q)
#:use-module (ice-9 match)
#:use-module (ice-9 receive)
list->q make-q*
- <time-segment>
- make-time-segment time-segment?
- time-segment-time time-segment-queue
-
- time< time= time<= time-delta+
- time-minus time-plus
-
- <time-delta>
- make-time-delta tdelta time-delta?
- time-delta-sec time-delta-usec
-
<schedule>
make-schedule schedule?
schedule-add! schedule-empty?
run-it wrap wrap-apply run run-at run-delay
8sync
- 8sleep 8usleep
+ 8sleep 8yield
;; used for introspecting the error, but a method for making
;; is not exposed
stop-on-nothing-to-do
- %current-agenda
- start-agenda agenda-run-once))
-
-;; @@: Using immutable agendas here, so wouldn't it make sense to
-;; replace this queue stuff with using pfds based immutable queues?
+ %current-agenda-prompt
+ run-agenda agenda-run-once!))
\f
;;; Agenda definition
;;; operation (from which they can be returned later)
;;; - a mapping of ports to various handler procedures
;;;
-;;; The goal, eventually, is for this all to be immutable and functional.
+;;; @@: Is this next part deprecated?
+;;; The goal, maybe eventually, is for this all to be immutable and functional.
;;; However, we aren't there yet. Some tricky things:
;;; - The schedule needs to be immutable, yet reasonably efficient.
;;; - Need to use immutable queues (ijp's pfds library?)
;;; - Modeling reading from ports as something repeatable,
;;; and with reasonable separation from functional components?
-(define-immutable-record-type <agenda>
+;; TODO: Tear out the immutable agenda aspect until we're actually ready
+;; to use it.
+(define-record-type <agenda>
(make-agenda-intern queue prompt-tag
read-port-map write-port-map
- schedule time catch-handler pre-unwind-handler)
+ schedule catch-handler pre-unwind-handler)
agenda?
- (queue agenda-queue)
+ (queue agenda-queue set-agenda-queue!)
(prompt-tag agenda-prompt-tag)
(read-port-map agenda-read-port-map)
(write-port-map agenda-write-port-map)
(schedule agenda-schedule)
- (time agenda-time)
(catch-handler agenda-catch-handler)
(pre-unwind-handler agenda-pre-unwind-handler))
(read-port-map (make-hash-table))
(write-port-map (make-hash-table))
(schedule (make-schedule))
- (time (gettimeofday))
(catch-handler #f)
(pre-unwind-handler print-error-and-continue))
;; TODO: document arguments
"Make a fresh agenda."
(make-agenda-intern queue prompt
read-port-map write-port-map
- schedule time
- catch-handler pre-unwind-handler))
-
-(define (current-agenda-prompt)
- "Get the prompt for the current agenda; signal an error if there isn't one."
- (let ((current-agenda (%current-agenda)))
- (if (not current-agenda)
- (throw
- 'no-current-agenda
- "Can't get current agenda prompt if there's no current agenda!")
- (agenda-prompt-tag current-agenda))))
+ schedule catch-handler pre-unwind-handler))
;; helper for making queues for an agenda
(define (list->q lst)
(time time-segment-time)
(queue time-segment-queue))
-;; @@: This seems to be the same as srfi-18's seconds->time procedure?
-;; Maybe double check and switch to that? (Thanks amz3!)
-
-(define (time-from-float-or-fraction time)
- "Produce a (sec . usec) pair from TIME, a float or fraction"
- (let* ((mixed-whole (floor time))
- (mixed-rest (- time mixed-whole)) ; float or fraction component
- (sec mixed-whole)
- (usec (floor (* 1000000 mixed-rest))))
- (cons (inexact->exact sec) (inexact->exact usec))))
-
-(define (time-segment-right-format time)
- "Ensure TIME is in the right format.
-
-The right format means (second . microsecond).
-If an integer, will convert appropriately."
- ;; TODO: add floating point / rational number support.
- (match time
- ;; time is already a cons of second and microsecnd
- (((? integer? s) . (? integer? u)) time)
- ;; time was just an integer (just the second)
- ((? integer? _) (cons time 0))
- ((or (? rational? _) (? inexact? _))
- (time-from-float-or-fraction time))
- (_ (throw 'invalid-time "Invalid time" time))))
-
(define* (make-time-segment time #:optional (queue (make-q)))
"Make a time segment of TIME and QUEUE
(or (time< time1 time2)
(time= time1 time2)))
-
-(define-record-type <time-delta>
- (make-time-delta-intern sec usec)
- time-delta?
- (sec time-delta-sec)
- (usec time-delta-usec))
-
-(define* (make-time-delta time)
- "Make a <time-delta> of SEC seconds and USEC microseconds.
-
-This is used primarily so the agenda can recognize RUN-REQUEST objects
-which are meant to delay computation"
- (match (time-segment-right-format time)
- ((sec . usec)
- (make-time-delta-intern sec usec))))
-
-(define tdelta make-time-delta)
-
+;; @@: Maybe we should use floor/ here?
(define (time-carry-correct time)
"Corrects/handles time microsecond carry.
Will produce (0 . 0) instead of a negative number, if needed."
(+ (cdr time) 1000000))))
(else time)))
-(define (time-delta+ time time-delta)
- "Increment a TIME by the value of TIME-DELTA"
- (time-carry-correct
- (cons (+ (car time) (time-delta-sec time-delta))
- (+ (cdr time) (time-delta-usec time-delta)))))
-
(define (time-minus time1 time2)
"Subtract TIME2 from TIME1"
(time-carry-correct
(cons (- (car time1) (car time2))
(- (cdr time1) (cdr time2)))))
+;; @@: Unused?
(define (time-plus time1 time2)
"Add TIME1 and TIME2"
(time-carry-correct
(cons (+ (car time1) (car time2))
(+ (cdr time1) (cdr time2)))))
-
(define-record-type <schedule>
(make-schedule-intern segments)
schedule?
;; a more functional setup?
(define (schedule-add! schedule time proc)
"Mutate SCHEDULE, adding PROC at an appropriate time segment for TIME"
- (let ((time (time-segment-right-format time)))
- (define (new-time-segment)
- (let ((new-segment
- (make-time-segment time)))
- (enq! (time-segment-queue new-segment) proc)
- new-segment))
- (define (loop segments)
- (define (segment-equals-time? segment)
- (time= time (time-segment-time segment)))
-
- (define (segment-more-than-time? segment)
- (time< time (time-segment-time segment)))
-
- ;; We could switch this out to be more mutate'y
- ;; and avoid the O(n) of space... is that over-optimizing?
- (match segments
- ;; If we're at the end of the list, time to make a new
- ;; segment...
- ('() (cons (new-time-segment) '()))
- ;; If the segment's time is exactly our time, good news
- ;; everyone! Let's append our stuff to its queue
- (((? segment-equals-time? first) rest ...)
- (enq! (time-segment-queue first) proc)
- segments)
- ;; If the first segment is more than our time,
- ;; ours belongs before this one, so add it and
- ;; start consing our way back
- (((? segment-more-than-time? first) rest ...)
- (cons (new-time-segment) segments))
- ;; Otherwise, build up recursive result
- ((first rest ... )
- (cons first (loop rest)))))
- (set-schedule-segments!
- schedule
- (loop (schedule-segments schedule)))))
+ (define (new-time-segment)
+ (let ((new-segment
+ (make-time-segment time)))
+ (enq! (time-segment-queue new-segment) proc)
+ new-segment))
+ (define (loop segments)
+ (define (segment-equals-time? segment)
+ (time= time (time-segment-time segment)))
+
+ (define (segment-more-than-time? segment)
+ (time< time (time-segment-time segment)))
+
+ ;; We could switch this out to be more mutate'y
+ ;; and avoid the O(n) of space... is that over-optimizing?
+ (match segments
+ ;; If we're at the end of the list, time to make a new
+ ;; segment...
+ ('() (cons (new-time-segment) '()))
+ ;; If the segment's time is exactly our time, good news
+ ;; everyone! Let's append our stuff to its queue
+ (((? segment-equals-time? first) rest ...)
+ (enq! (time-segment-queue first) proc)
+ segments)
+ ;; If the first segment is more than our time,
+ ;; ours belongs before this one, so add it and
+ ;; start consing our way back
+ (((? segment-more-than-time? first) rest ...)
+ (cons (new-time-segment) segments))
+ ;; Otherwise, build up recursive result
+ ((first rest ... )
+ (cons first (loop rest)))))
+ (set-schedule-segments!
+ schedule
+ (loop (schedule-segments schedule))))
(define (schedule-empty? schedule)
"Check if the SCHEDULE is currently empty"
(define (schedule-segments-split schedule time)
"Does a multiple value return of time segments before/at and after TIME"
- (let ((time (time-segment-right-format time)))
- (define (segment-is-now? segment)
- (time= (time-segment-time segment) time))
- (define (segment-is-before-now? segment)
- (time< (time-segment-time segment) time))
-
- (let loop ((segments-before '())
- (segments-left (schedule-segments schedule)))
- (match segments-left
- ;; end of the line, return
- ('()
- (values (reverse segments-before) '()))
-
- ;; It's right now, so time to stop, but include this one in before
- ;; but otherwise return
- (((? segment-is-now? first) rest ...)
- (values (reverse (cons first segments-before)) rest))
-
- ;; This is prior or at now, so add it and keep going
- (((? segment-is-before-now? first) rest ...)
- (loop (cons first segments-before) rest))
-
- ;; Otherwise it's past now, just return what we have
- (segments-after
- (values segments-before segments-after))))))
+ (define (segment-is-now? segment)
+ (time= (time-segment-time segment) time))
+ (define (segment-is-before-now? segment)
+ (time< (time-segment-time segment) time))
+
+ (let loop ((segments-before '())
+ (segments-left (schedule-segments schedule)))
+ (match segments-left
+ ;; end of the line, return
+ ('()
+ (values (reverse segments-before) '()))
+
+ ;; It's right now, so time to stop, but include this one in before
+ ;; but otherwise return
+ (((? segment-is-now? first) rest ...)
+ (values (reverse (cons first segments-before)) rest))
+
+ ;; This is prior or at now, so add it and keep going
+ (((? segment-is-before-now? first) rest ...)
+ (loop (cons first segments-before) rest))
+
+ ;; Otherwise it's past now, just return what we have
+ (segments-after
+ (values segments-before segments-after)))))
(define (schedule-extract-until! schedule time)
"Extract all segments until TIME from SCHEDULE, and pop old segments off"
"Run BODY at WHEN"
(make-run-request (wrap body ...) when))
-;; @@: Is it okay to overload the term "delay" like this?
-;; Would `run-in' be better?
(define-syntax-rule (run-delay body ... delay-time)
"Run BODY at DELAY-TIME time from now"
- (make-run-request (wrap body ...) (tdelta delay-time)))
+ (make-run-request (wrap body ...) (delayed-time delay-time)))
+
+;;; Procedures that are delimited continuations being resumed are
+;;; wrapped in a <kontinue>. This is so that we don't accidentally
+;;; wrap in another catch statement every time we resume them, which
+;;; would be a drag.
+
+(define-record-type <kontinue>
+ (kontinue kont)
+ kontinue?
+ (kont kontinue-kont))
\f
;;; =================================
(define-syntax-rule (8sync-abort-to-prompt async-request)
- (abort-to-prompt (current-agenda-prompt)
+ (abort-to-prompt (%current-agenda-prompt)
async-request))
;; Async port request and run-request meta-requests
(make-async-request
(lambda (kont)
(list (make-run-request
- ;; What's with returning #f to kont?
- ;; Otherwise we sometimes get errors like
- ;; "Zero values returned to single-valued continuation""
- (wrap (kont #f)) #f)
+ (kontinue kont) #f)
(make-run-request (lambda () body ...) #f))))))
+(define (delayed-time in-secs)
+ "Calculate a cons of '(sec . usec) of IN-SECS from current time"
+ (define cur-time (gettimeofday))
+ (define cur-secs (car cur-time))
+ (define cur-usecs (cdr cur-time))
+ (define (convert-non-integer)
+ (define next-time-in-usecs
+ (+ (* (+ in-secs cur-secs) ; add our seconds to current seconds
+ 1000000) ; and turn into usecs
+ cur-usecs)) ; then add in current usecs
+ ;; convert into sec / usec pair
+ (receive (secs usecs)
+ (floor/ next-time-in-usecs 1000000)
+ (cons secs (floor usecs))))
+ (define (convert-integer)
+ (cons (+ in-secs cur-secs) cur-usecs))
+ (if (integer? in-secs)
+ (convert-integer)
+ (convert-non-integer)))
+
;; TODO: Rewrite when we move to this being just `sleep'.
(define (8sleep secs)
"Like sleep, but asynchronous."
(8sync-abort-to-prompt
(make-async-request
(lambda (kont)
- (make-run-request (lambda () (kont #f)) (tdelta secs))))))
-
-(define (8usleep usecs)
- "Like usleep, but asynchronous."
- (define (usecs->time-pair)
- (if (< 1000000)
- (cons 0 usecs)
- (let* ((sec (floor (/ usecs 1000000)))
- (msec (- usecs (* sec 1000000))))
- (cons sec msec))))
- (8sync-abort-to-prompt
- (make-async-request
- (lambda (kont)
- (make-run-request (lambda () (kont #f)) (tdelta usecs->time-pair))))))
+ (make-run-request (kontinue kont) (delayed-time secs))))))
;; Voluntarily yield execution
-(define (yield) ; @@: should this be define-inlinable?
+(define (8yield)
"Voluntarily yield execution to the scheduler."
(8sync-abort-to-prompt
(make-async-request
(lambda (kont)
- (make-run-request (lambda () (kont #f)) #f)))))
+ (make-run-request (kontinue kont) #f)))))
\f
;;; Execution of agenda, and current agenda
;;; =======================================
-(define %current-agenda (make-parameter #f))
+(define %current-agenda-prompt (make-parameter #f))
(define (update-agenda-from-select! agenda)
"Potentially (select) on ports specified in agenda, adding items to queue.
((not (q-empty? (agenda-queue agenda)))
(cons 0 0))
(soonest-time ; ie, the agenda is non-empty
- (let* ((current-time (agenda-time agenda)))
+ (let* ((current-time (gettimeofday)))
(if (time<= soonest-time current-time)
;; Well there's something due so let's select
;; (this avoids a (possible?) race condition chance)
(= 0 (hash-count (const #t) (agenda-write-port-map agenda)))))
-(define* (start-agenda agenda
- #:key
- ;; @@: Should we make stop-on-nothing-to-do
- ;; the default stop-condition?
- (stop-condition stop-on-nothing-to-do)
- (get-time gettimeofday)
- (handle-ports update-agenda-from-select!)
- ;; For live hacking madness, etc
- (post-run-hook #f))
+(define* (run-agenda agenda
+ #:key (stop-condition stop-on-nothing-to-do)
+ ;; For live hacking madness, etc
+ (post-run-hook #f))
;; TODO: Document fields
"Start up the AGENDA"
(install-suspendable-ports!)
- (let loop ((agenda agenda))
- (let ((agenda
- ;; @@: Hm, maybe here would be a great place to handle
- ;; select'ing on ports.
- ;; We could compose over agenda-run-once and agenda-read-ports
- (agenda-run-once agenda)))
- ;; @@: This relies on mutation at present on the queue, in the rare
- ;; event it's used. If we ever switch to something more immutable,
- ;; it should return a new modified agenda instead.
+ (parameterize ((%current-agenda-prompt (agenda-prompt-tag agenda))
+ (current-read-waiter wait-for-readable)
+ (current-write-waiter wait-for-writable))
+ (while (not (stop-condition agenda))
+ (agenda-run-once! agenda)
+ (update-agenda-from-select! agenda)
+ (add-segments-contents-to-queue!
+ (schedule-extract-until! (agenda-schedule agenda) (gettimeofday))
+ (agenda-queue agenda))
(if post-run-hook
- (post-run-hook agenda))
- (if (and stop-condition (stop-condition agenda))
- 'done
- (let* ((agenda
- ;; We have to update the time after ports handled, too
- ;; because it may have changed after a select
- (set-field
- (handle-ports
- ;; Adjust the agenda's time just in time
- ;; We do this here rather than in agenda-run-once to make
- ;; agenda-run-once's behavior fairly predictable
- (set-field agenda (agenda-time) (get-time)))
- (agenda-time) (get-time))))
- ;; Update the agenda's current queue based on
- ;; currently applicable time segments
- (add-segments-contents-to-queue!
- (schedule-extract-until! (agenda-schedule agenda) (agenda-time agenda))
- (agenda-queue agenda))
- (loop agenda))))))
-
+ (post-run-hook agenda))))
+ 'done)
(define (print-error-and-continue key . args)
"Frequently used as pre-unwind-handler for agenda"
(lambda (kont)
(make-write-request port (wrap (kont #f)))))))
-(define (agenda-run-once agenda)
+(define (agenda-run-once! agenda)
"Run once through the agenda, and produce a new agenda
based on the results"
+ ;; @@: Maybe rename proc -> run-this ?
(define (call-proc proc)
(call-with-prompt
(agenda-prompt-tag agenda)
(lambda ()
- (parameterize ((%current-agenda agenda)
- ;; @@: Couldn't we just parameterize this at the start of
- ;; the agenda...?
- (current-read-waiter wait-for-readable)
- (current-write-waiter wait-for-writable))
- (maybe-catch-all
- ((agenda-catch-handler agenda)
- (agenda-pre-unwind-handler agenda))
- (proc))))
+ (if (kontinue? proc)
+ ;; Resume continuation.
+ ;; We need to pass in #f, otherwise we sometimes get errors like
+ ;; "Zero values returned to single-valued continuation""
+ ((kontinue-kont proc) #f)
+ ;; Otherwise call the procedure and set up error catching.
+ (maybe-catch-all
+ ((agenda-catch-handler agenda)
+ (agenda-pre-unwind-handler agenda))
+ (proc))))
(lambda (kont async-request)
(setup-async-request kont async-request))))
(proc-result (call-proc proc))
(enqueue
(lambda (run-request)
- (define (schedule-at! time proc)
- (schedule-add! (agenda-schedule agenda) time proc))
(let ((request-time (run-request-when run-request)))
- (match request-time
- ((? time-delta? time-delta)
- (let ((time (time-delta+ (agenda-time agenda)
- time-delta)))
- (schedule-at! time (run-request-proc run-request))))
- ((? integer? sec)
- (let ((time (cons sec 0)))
- (schedule-at! time (run-request-proc run-request))))
- (((? integer? sec) . (? integer? usec))
- (schedule-at! request-time (run-request-proc run-request)))
- (#f
- (enq! next-queue (run-request-proc run-request))))))))
+ (if request-time
+ (schedule-add! (agenda-schedule agenda) request-time
+ (run-request-proc run-request))
+ (enq! next-queue (run-request-proc run-request)))))))
(define (handle-individual result)
;; @@: Could maybe optimize by switching to an explicit cond...
(match result
((results ...)
(for-each handle-individual results))
(one-result (handle-individual one-result)))))
- ;; TODO: Alternately, we could return the next-queue
- ;; along with changes to be added to the schedule here?
- ;; Return new agenda, with next queue set
- (set-field agenda (agenda-queue) next-queue)))
+ (set-agenda-queue! agenda next-queue)))
projects / 8sync.git / blobdiff