X-Git-Url: https://jxself.org/git/?a=blobdiff_plain;f=loopy.scm;h=f346a9e1a61bb95b992edc3b6116087d9cb83147;hb=7b1f63e7291f376d73ead3fe368315781258d0ed;hp=f11b6b8503b2d235c00544b31956052ff718c28e;hpb=68e8784ebff46e4cfe588d6f13593709b51fe242;p=8sync.git diff --git a/loopy.scm b/loopy.scm index f11b6b8..f346a9e 100644 --- a/loopy.scm +++ b/loopy.scm @@ -1,4 +1,5 @@ (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) @@ -7,7 +8,8 @@ #:export ( 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 @@ -15,20 +17,21 @@ make-time-segment time-segment? time-segment-time time-segment-queue - time-< time-= time-<= + time-< time-= time-<= time-+ + + + make-time-delta tdelta time-delta? + time-delta-sec time-delta-usec 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? - make-run-request run-request? run-request-proc run-request-when @@ -60,12 +63,17 @@ ;;; and with reasonable separation from functional components? (define-immutable-record-type - (make-agenda-intern queue prompt-tag port-mapping schedule) + (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) - (schedule agenda-schedule)) + (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-async-prompt-tag) (make-prompt-tag "prompt")) @@ -73,9 +81,14 @@ (define* (make-agenda #:key (queue (make-q)) (prompt (make-prompt-tag)) - (port-mapping (make-port-mapping)) - (schedule (make-schedule))) - (make-agenda-intern queue prompt port-mapping schedule)) + (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 + read-port-map write-port-map except-port-map + schedule time)) @@ -84,7 +97,7 @@ ;;; 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) @@ -125,6 +138,23 @@ (or (time-< time1 time2) (time-= time1 time2))) + +(define-record-type + (make-time-delta-intern sec usec) + time-delta? + (sec time-delta-sec) + (usec time-delta-usec)) + +(define* (make-time-delta sec #:optional usec) + (make-time-delta-intern sec (or usec 0))) + +(define tdelta make-time-delta) + +(define (time-+ time time-delta) + (cons (+ (car time) (time-delta-sec time-delta)) + (+ (cdr time) (time-delta-usec time-delta)))) + + (define-record-type (make-schedule-intern segments) schedule? @@ -133,11 +163,18 @@ (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 ;; a more functional setup? -(define (schedule-add! time proc schedule) +(define (schedule-add! schedule time proc) (let ((time (time-segment-right-format time))) (define (new-time-segment) (let ((new-segment @@ -280,9 +317,89 @@ (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))) + (values 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) + (values 0 0) + (values + (- (car soonest-time) (car current-time)) + (- (cdr soonest-time) (cdr current-time)))))) + (else + (values #f #f))))) + (define (do-select) + ;; TODO: support usecond wait time too + (receive (sec usec) + (get-wait-time) + (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 @@ -290,7 +407,19 @@ (agenda-run-once agenda)))) (if (and stop-condition (stop-condition agenda)) 'done - (loop new-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 @@ -310,11 +439,21 @@ based on the results" (proc-result (call-proc proc)) (enqueue (lambda (run-request) - (cond - ((run-request-when run-request) - (error "TODO")) - (else - (enq! next-queue (run-request-proc 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-+ (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)))))))) ;; @@: We might support delay-wrapped procedures here (match proc-result ;; TODO: replace procedure with something that indicates @@ -328,6 +467,7 @@ based on the results" new-procs)) ;; do nothing (_ #f)))) - ;; TODO: Selecting on ports would happen here? + ;; 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)))