(define-module (loopy agenda)
+ #:use-module (srfi srfi-1)
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-9 gnu)
#:use-module (ice-9 q)
#:export (<agenda>
make-agenda agenda?
agenda-queue agenda-prompt-tag
- agenda-port-pmapping agenda-schedule
+ agenda-read-port-map agenda-write-port-map agenda-except-port-map
+ agenda-schedule
make-async-prompt-tag
make-time-segment time-segment?
time-segment-time time-segment-queue
- time-< time-= time-<= time-+
+ time< time= time<= time-delta+
+ time-minus time-plus
<time-delta>
- make-time-delta time-delta?
+ make-time-delta tdelta time-delta?
time-delta-sec time-delta-usec
<schedule>
make-schedule schedule?
schedule-add! schedule-empty?
schedule-segments
+ schedule-soonest-time
schedule-segments-split schedule-extract-until!
add-segments-contents-to-queue!
- make-port-mapping
- port-mapping-set! port-mapping-remove!
- port-mapping-empty? port-mapping-non-empty?
-
<run-request>
make-run-request run-request?
run-request-proc run-request-when
;;; and with reasonable separation from functional components?
(define-immutable-record-type <agenda>
- (make-agenda-intern queue prompt-tag port-mapping schedule time)
+ (make-agenda-intern queue prompt-tag
+ read-port-map write-port-map except-port-map
+ schedule time)
agenda?
(queue agenda-queue)
(prompt-tag agenda-prompt-tag)
- (port-mapping agenda-port-mapping)
+ (read-port-map agenda-read-port-map)
+ (write-port-map agenda-write-port-map)
+ (except-port-map agenda-except-port-map)
(schedule agenda-schedule)
(time agenda-time))
(define* (make-agenda #:key
(queue (make-q))
(prompt (make-prompt-tag))
- (port-mapping (make-port-mapping))
+ (read-port-map (make-hash-table))
+ (write-port-map (make-hash-table))
+ (except-port-map (make-hash-table))
(schedule (make-schedule))
(time (gettimeofday)))
- (make-agenda-intern queue prompt port-mapping schedule time))
+ (make-agenda-intern queue prompt
+ read-port-map write-port-map except-port-map
+ schedule time))
\f
;;; This is where we handle timed events for the future
-;; This section totally borrows from SICP
+;; This section totally borrows from the ideas in SICP
;; <3 <3 <3
;; NOTE: time is a cons of (seconds . microseconds)
(define* (make-time-segment time #:optional (queue (make-q)))
(make-time-segment-intern time queue))
-(define (time-< time1 time2)
+(define (time< time1 time2)
(cond ((< (car time1)
(car time2))
#t)
#t)
(else #f)))
-(define (time-= time1 time2)
+(define (time= time1 time2)
(and (= (car time1) (car time2))
(= (cdr time1) (cdr time2))))
-(define (time-<= time1 time2)
- (or (time-< time1 time2)
- (time-= time1 time2)))
+(define (time<= time1 time2)
+ (or (time< time1 time2)
+ (time= time1 time2)))
(define-record-type <time-delta>
(define* (make-time-delta sec #:optional usec)
(make-time-delta-intern sec (or usec 0)))
-(define (time-+ time time-delta)
- (cons (+ (car time) (time-delta-sec time-delta))
- (+ (cdr time) (time-delta-usec time-delta))))
+(define tdelta make-time-delta)
+
+(define (time-carry-correct time)
+ "Corrects/handles time microsecond carry.
+Will produce (0 . 0) instead of a negative number, if needed."
+ (cond ((>= (cdr time) 1000000)
+ (cons
+ (+ (car time) 1)
+ (- (cdr time) 1000000)))
+ ((< (cdr time) 0)
+ (if (= (car time) 0)
+ '(0 0)
+ (cons
+ (- (car time) 1)
+ (+ (cdr time) 1000000))))
+ (else time)))
+
+(define (time-delta+ time 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)
+ (time-carry-correct
+ (cons (- (car time1) (car time2))
+ (- (cdr time2) (cdr time2)))))
+
+(define (time-plus time1 time2)
+ (time-carry-correct
+ (cons (+ (car time1) (car time2))
+ (+ (cdr time2) (cdr time2)))))
(define-record-type <schedule>
(define* (make-schedule #:optional segments)
(make-schedule-intern (or segments '())))
+(define (schedule-soonest-time schedule)
+ "Return a cons of (sec . usec) for next time segement, or #f if none"
+ (let ((segments (schedule-segments schedule)))
+ (if (eq? segments '())
+ #f
+ (time-segment-time (car segments)))))
+
;; TODO: This code is reasonably easy to read but it
;; mutates AND is worst case of O(n) in both space and time :(
;; but at least it'll be reasonably easy to refactor to
new-segment))
(define (loop segments)
(define (segment-equals-time? segment)
- (time-= time (time-segment-time segment)))
+ (time= time (time-segment-time segment)))
(define (segment-more-than-time? segment)
- (time-< time (time-segment-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?
"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))
+ (time= (time-segment-time segment) time))
(define (segment-is-before-now? segment)
- (time-< (time-segment-time segment) time))
+ (time< (time-segment-time segment) time))
(let loop ((segments-before '())
(segments-left (schedule-segments schedule)))
(define %current-agenda (make-parameter #f))
-(define* (start-agenda agenda #:optional stop-condition)
+(define (update-agenda-from-select! agenda)
+ (define (hash-keys hash)
+ (hash-map->list (lambda (k v) k) hash))
+ (define (get-wait-time)
+ ;; TODO: we need to figure this out based on whether there's anything
+ ;; in the queue, and if not, how long till the next scheduled item
+ (let ((soonest-time (schedule-soonest-time (agenda-schedule agenda))))
+ (cond
+ ((not (q-empty? (agenda-queue agenda)))
+ (cons 0 0))
+ (soonest-time ; ie, the agenda is non-empty
+ (let* ((current-time (agenda-time agenda)))
+ (if (time<= soonest-time current-time)
+ ;; Well there's something due so let's select
+ ;; (this avoids a (possible?) race condition chance)
+ (cons 0 0)
+ (time-minus soonest-time current-time))))
+ (else
+ (cons #f #f)))))
+ (define (do-select)
+ ;; TODO: support usecond wait time too
+ (match (get-wait-time)
+ ((sec . usec)
+ (select (hash-keys (agenda-read-port-map agenda))
+ (hash-keys (agenda-write-port-map agenda))
+ (hash-keys (agenda-except-port-map agenda))
+ sec usec))))
+ (define (get-procs-to-run)
+ (define (ports->procs ports port-map)
+ (lambda (initial-procs)
+ (fold
+ (lambda (port prev)
+ (cons (lambda ()
+ ((hash-ref port-map port) port))
+ prev))
+ initial-procs
+ ports)))
+ (match (do-select)
+ ((read-ports write-ports except-ports)
+ ;; @@: Come on, we can do better than append ;P
+ ((compose (ports->procs
+ read-ports
+ (agenda-read-port-map agenda))
+ (ports->procs
+ write-ports
+ (agenda-write-port-map agenda))
+ (ports->procs
+ except-ports
+ (agenda-except-port-map agenda)))
+ '()))))
+ (define (update-agenda)
+ (let ((procs-to-run (get-procs-to-run))
+ (q (agenda-queue agenda)))
+ (for-each
+ (lambda (proc)
+ (enq! q proc))
+ procs-to-run))
+ agenda)
+ (define (ports-to-select?)
+ (define (has-items? selector)
+ ;; @@: O(n)
+ ;; ... we could use hash-for-each and a continuation to jump
+ ;; out with a #t at first indication of an item
+ (not (= (hash-count (const #t)
+ (selector agenda))
+ 0)))
+ (or (has-items? agenda-read-port-map)
+ (has-items? agenda-write-port-map)
+ (has-items? agenda-except-port-map)))
+
+ (if (ports-to-select?)
+ (update-agenda)
+ agenda))
+
+
+(define* (start-agenda agenda
+ #:key stop-condition
+ (get-time gettimeofday)
+ (handle-ports update-agenda-from-select!))
(let loop ((agenda agenda))
- (let ((new-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))))
(if (and stop-condition (stop-condition agenda))
'done
- (let ((updated-agenda
- ;; 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 new-agenda (agenda-time) (gettimeofday))))
- (loop updated-agenda))))))
+ (let* ((new-time (get-time))
+ (agenda
+ (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) new-time))))
+ ;; Update the agenda's current queue based on
+ ;; currently applicable time segments
+ (add-segments-contents-to-queue!
+ (schedule-extract-until! (agenda-schedule agenda) new-time)
+ (agenda-queue agenda))
+ (loop agenda))))))
(define (agenda-run-once agenda)
"Run once through the agenda, and produce a new agenda
(let ((request-time (run-request-when run-request)))
(match request-time
((? time-delta? time-delta)
- (let ((time (time-+ (agenda-time agenda)
- time-delta)))
- (schedule-at! time (run-request-proc proc))))
+ (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 proc))))
+ (schedule-at! time (run-request-proc run-request))))
(((? integer? sec) . (? integer? usec))
- (schedule-at! request-time (run-request-proc proc)))
+ (schedule-at! request-time (run-request-proc run-request)))
(#f
(enq! next-queue (run-request-proc run-request))))))))
;; @@: We might support delay-wrapped procedures here
projects / 8sync.git / blobdiff