X-Git-Url: https://jxself.org/git/?p=8sync.git;a=blobdiff_plain;f=8sync%2Fagenda.scm;h=4a126a4e1fddbcf140748f62b7b9861f7d5e03e2;hp=118bb28d9a53374af007ab0826e08c30b0e4b29f;hb=2255f6996a4fbe708b235760816a6dd49959fb6d;hpb=ad2cc60c709045ba78a7957b149be86b4a21b49c diff --git a/8sync/agenda.scm b/8sync/agenda.scm index 118bb28..4a126a4 100644 --- a/8sync/agenda.scm +++ b/8sync/agenda.scm @@ -19,7 +19,6 @@ (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) @@ -34,17 +33,6 @@ list->q make-q* - - make-time-segment time-segment? - time-segment-time time-segment-queue - - time< time= time<= time-delta+ - time-minus time-plus - - - make-time-delta tdelta time-delta? - time-delta-sec time-delta-usec - make-schedule schedule? schedule-add! schedule-empty? @@ -60,10 +48,8 @@ run-it wrap wrap-apply run run-at run-delay - 8sync-delay - 8sync-run 8sync-run-at 8sync-run-delay 8sync - 8sleep + 8sleep 8yield ;; used for introspecting the error, but a method for making ;; is not exposed @@ -75,13 +61,8 @@ stop-on-nothing-to-do - %current-agenda - start-agenda agenda-run-once)) - -(install-suspendable-ports!) - -;; @@: 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!)) ;;; Agenda definition @@ -94,24 +75,26 @@ ;;; 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 +;; TODO: Tear out the immutable agenda aspect until we're actually ready +;; to use it. +(define-record-type (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)) @@ -127,24 +110,13 @@ Generally done automatically for the user through (make-agenda)." (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) @@ -177,32 +149,6 @@ Generally done automatically for the user through (make-agenda)." (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 @@ -232,24 +178,7 @@ run (time-segment-right-format) first." (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 time) - "Make a 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." @@ -265,25 +194,19 @@ 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 (make-schedule-intern segments) schedule? @@ -306,41 +229,40 @@ Will produce (0 . 0) instead of a negative number, if needed." ;; 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" @@ -348,31 +270,30 @@ Will produce (0 . 0) instead of a negative number, if needed." (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" @@ -425,11 +346,19 @@ Will produce (0 . 0) instead of a negative number, if needed." "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 . 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 kont) + kontinue? + (kont kontinue-kont)) @@ -437,7 +366,7 @@ Will produce (0 . 0) instead of a negative number, if needed." ;;; ================================= (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 @@ -466,32 +395,50 @@ forge ahead in our current function!" (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 time) +(define (8sleep secs) + "Like sleep, but asynchronous." (8sync-abort-to-prompt (make-async-request (lambda (kont) - (make-run-request (lambda () (kont #f)) (tdelta time)))))) + (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))))) ;;; 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. @@ -507,7 +454,7 @@ Also handles sleeping when all we have to do is wait on the schedule." ((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) @@ -606,47 +553,25 @@ on suspendable ports." (= 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" - (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. + (install-suspendable-ports!) + (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" @@ -695,22 +620,24 @@ on suspendable ports." (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)))) @@ -721,21 +648,11 @@ based on the results" (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 @@ -756,7 +673,4 @@ based on the results" ((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)))