#: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 match)
+ #:use-module (ice-9 receive)
+ #:export (<agenda>
+ make-agenda agenda?
+ agenda-queue agenda-prompt-tag
+ agenda-port-pmapping agenda-schedule
+
+ make-async-prompt-tag
+
+ <time-segment>
+ make-time-segment time-segment?
+ time-segment-time time-segment-queue
+
+ time-< time-= time-<= time-+
+
+ <time-delta>
+ make-time-delta time-delta?
+ time-delta-sec time-delta-usec
+
+ <schedule>
+ make-schedule schedule?
+ schedule-add! schedule-empty?
+ schedule-segments
+
+ 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
+
+ run wrap run-wrap run-wrap-at
+
+ %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?
+\f
+;;; Agenda definition
+;;; =================
+
;;; The agenda consists of:
;;; - a queue of immediate items to handle
;;; - sheduled future events to be added to a future queue
;;; and with reasonable separation from functional components?
(define-immutable-record-type <agenda>
- (make-agenda-intern queue prompt-tag port-mapping schedule)
+ (make-agenda-intern queue prompt-tag port-mapping schedule time)
agenda?
(queue agenda-queue)
(prompt-tag agenda-prompt-tag)
(port-mapping agenda-port-mapping)
- (schedule agenda-schedule))
+ (schedule agenda-schedule)
+ (time agenda-time))
(define (make-async-prompt-tag)
(make-prompt-tag "prompt"))
(queue (make-q))
(prompt (make-prompt-tag))
(port-mapping (make-port-mapping))
- (schedule (make-schedule)))
- (make-agenda-intern queue prompt port-mapping schedule))
+ (schedule (make-schedule))
+ (time (gettimeofday)))
+ (make-agenda-intern queue prompt port-mapping schedule time))
+\f
;;; Schedule
-;;;
+;;; ========
+
;;; 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)
(make-time-segment-intern time queue)
time-segment?
(time time-segment-time)
- (queue time-segment-queue time-segment-set-queue!))
+ (queue time-segment-queue))
(define (time-segment-right-format time)
(match time
;; time is already a cons of second and microsecnd
- (((? integer? s) (? integer? u)) time)
+ (((? integer? s) . (? integer? u)) time)
;; time was just an integer (just the second)
((? integer? _) (cons time 0))
(_ (throw 'invalid-time "Invalid time" time))))
(define* (make-time-segment time #:optional (queue (make-q)))
(make-time-segment-intern time queue))
-(define (make-schedule)
- '())
-
(define (time-< time1 time2)
(cond ((< (car time1)
(car time2))
(and (= (car time1) (car time2))
(= (cdr time1) (cdr time2))))
-(define (schedule-add! time proc schedule)
+(define (time-<= time1 time2)
+ (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 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-record-type <schedule>
+ (make-schedule-intern segments)
+ schedule?
+ (segments schedule-segments set-schedule-segments!))
+
+(define* (make-schedule #:optional segments)
+ (make-schedule-intern (or 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! schedule time proc)
(let ((time (time-segment-right-format time)))
- (define (belongs-before? segments)
- (or (null? segments)
- (error))
- )
+ (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)))
- ;; Find and add a schedule segment
- (error)))
+ (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)
- (eq? schedule '()))
+ (eq? (schedule-segments schedule) '()))
+
+(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 (schedule-extract-until! schedule time)
+ "Extract all segments until TIME from SCHEDULE, and pop old segments off"
+ (receive (segments-before segments-after)
+ (schedule-segments-split schedule time)
+ (set-schedule-segments! schedule segments-after)
+ segments-before))
+
+(define (add-segments-contents-to-queue! segments queue)
+ (for-each
+ (lambda (segment)
+ (let ((seg-queue (time-segment-queue segment)))
+ (while (not (q-empty? seg-queue))
+ (enq! queue (deq! seg-queue)))))
+ segments))
+
+
+\f
;;; Port handling
+;;; =============
(define (make-port-mapping)
(make-hash-table))
(not (port-mapping-empty? port-mapping)))
+\f
+;;; Request to run stuff
+;;; ====================
+
+(define-record-type <run-request>
+ (make-run-request proc when)
+ run-request?
+ (proc run-request-proc)
+ (when run-request-when))
+
+(define* (run proc #:optional when)
+ (make-run-request proc when))
+
+(define-syntax-rule (wrap body ...)
+ (lambda ()
+ body ...))
+
+(define-syntax-rule (run-wrap body ...)
+ (run (wrap body ...)))
+
+(define-syntax-rule (run-wrap-at body ... when)
+ (run (wrap body ...) when))
+
+\f
;;; Execution of agenda, and current agenda
+;;; =======================================
(define %current-agenda (make-parameter #f))
(agenda-run-once agenda))))
(if (and stop-condition (stop-condition agenda))
'done
- (loop new-agenda)))))
+ (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))))))
(define (agenda-run-once agenda)
"Run once through the agenda, and produce a new agenda
(let* ((proc (q-pop! queue))
(proc-result (call-proc proc))
(enqueue
- (lambda (new-proc)
- (enq! next-queue new-proc))))
+ (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-+ (agenda-time agenda)
+ time-delta)))
+ (schedule-at! time (run-request-proc proc))))
+ ((? integer? sec)
+ (let ((time (cons sec 0)))
+ (schedule-at! time (run-request-proc proc))))
+ (((? integer? sec) . (? integer? usec))
+ (schedule-at! request-time (run-request-proc proc)))
+ (#f
+ (enq! next-queue (run-request-proc run-request))))))))
;; @@: We might support delay-wrapped procedures here
(match proc-result
- ((? procedure? new-proc)
+ ;; TODO: replace procedure with something that indicates
+ ;; intent to run. Use a (run foo) procedure
+ ((? run-request? new-proc)
(enqueue new-proc))
- (((? procedure? new-procs) ...)
+ (((? run-request? new-procs) ...)
(for-each
(lambda (new-proc)
(enqueue new-proc))
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)))
projects / 8sync.git / blobdiff