X-Git-Url: https://jxself.org/git/?p=8sync.git;a=blobdiff_plain;f=loopy.scm;h=8ffe6f18a489a94520f0a1058f0d9a8e3ca1da8a;hp=f11b6b8503b2d235c00544b31956052ff718c28e;hb=302b13a687285471ba67d62553639519adfb4da8;hpb=68e8784ebff46e4cfe588d6f13593709b51fe242 diff --git a/loopy.scm b/loopy.scm index f11b6b8..8ffe6f1 100644 --- a/loopy.scm +++ b/loopy.scm @@ -1,4 +1,22 @@ -(define-module (loopy agenda) +;; Copyright (C) 2015 Christopher Allan Webber + +;; This library is free software; you can redistribute it and/or +;; modify it under the terms of the GNU Lesser General Public +;; License as published by the Free Software Foundation; either +;; version 3 of the License, or (at your option) any later version. +;; +;; This library is distributed in the hope that it will be useful, +;; but WITHOUT ANY WARRANTY; without even the implied warranty of +;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +;; Lesser General Public License for more details. +;; +;; You should have received a copy of the GNU Lesser General Public +;; License along with this library; if not, write to the Free Software +;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +;; 02110-1301 USA + +(define-module (eightsync agenda) + #:use-module (srfi srfi-1) #:use-module (srfi srfi-9) #:use-module (srfi srfi-9 gnu) #:use-module (ice-9 q) @@ -7,7 +25,8 @@ #: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 @@ -15,26 +34,38 @@ make-time-segment time-segment? time-segment-time time-segment-queue - time-< time-= time-<= + 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? 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? + %sync 8sync make-run-request run-request? run-request-proc run-request-when - run wrap run-wrap run-wrap-at + + make-port-request port-request port-request? + port-request-port + port-request-read port-request-write port-request-except + + run-it wrap run run-at run-delay + %port-request %run %run-at %run-delay + 8port-request 8run 8run-at 8run-delay + %current-agenda start-agenda agenda-run-once)) @@ -60,22 +91,46 @@ ;;; 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 an async prompt tag for an agenda. + +Generally done automatically for the user through (make-agenda)." (make-prompt-tag "prompt")) (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))) + ;; TODO: document arguments + "Make a fresh agenda." + (make-agenda-intern queue prompt + read-port-map write-port-map except-port-map + schedule time)) + +(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)))) @@ -84,7 +139,7 @@ ;;; 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) @@ -96,6 +151,11 @@ (queue time-segment-queue)) (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) @@ -104,9 +164,14 @@ (_ (throw 'invalid-time "Invalid time" time)))) (define* (make-time-segment time #:optional (queue (make-q))) + "Make a time segment of TIME and QUEUE + +No automatic conversion is done, so you might have to +run (time-segment-right-format) first." (make-time-segment-intern time queue)) -(define (time-< time1 time2) +(define (time< time1 time2) + "Check if TIME1 is less than TIME2" (cond ((< (car time1) (car time2)) #t) @@ -117,13 +182,65 @@ #t) (else #f))) -(define (time-= time1 time2) +(define (time= time1 time2) + "Check whether TIME1 and TIME2 are equivalent" (and (= (car time1) (car time2)) (= (cdr time1) (cdr time2)))) -(define (time-<= time1 time2) - (or (time-< time1 time2) - (time-= time1 time2))) +(define (time<= time1 time2) + "Check if TIME1 is less than or equal to TIME2" + (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 0)) + "Make a of SEC seconds and USEC microseconds. + +This is used primarily so the agenda can recognize RUN-REQUEST objects +which are meant " + (make-time-delta-intern sec usec)) + +(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) + "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 time2) (cdr time2))))) + +(define (time-plus time1 time2) + "Add TIME1 and TIME2" + (time-carry-correct + (cons (+ (car time1) (car time2)) + (+ (cdr time2) (cdr time2))))) + (define-record-type (make-schedule-intern segments) @@ -131,13 +248,22 @@ (segments schedule-segments set-schedule-segments!)) (define* (make-schedule #:optional segments) + "Make a schedule, optionally pre-composed of 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) + "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 @@ -146,10 +272,10 @@ 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? @@ -175,15 +301,16 @@ (loop (schedule-segments schedule))))) (define (schedule-empty? schedule) + "Check if the SCHEDULE is currently empty" (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)) + (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))) @@ -221,36 +348,6 @@ segments)) - -;;; Port handling -;;; ============= - -(define (make-port-mapping) - (make-hash-table)) - -(define* (port-mapping-set! port-mapping port #:optional read write except) - "Sets port-mapping for reader / writer / exception handlers" - (if (not (or read write except)) - (throw 'no-handlers-given "No handlers given for port" port)) - (hashq-set! port-mapping port - `#(,read ,write ,except))) - -(define (port-mapping-remove! port-mapping port) - (hashq-remove! port-mapping port)) - -;; TODO: This is O(n), I'm pretty sure :\ -;; ... it might be worthwhile for us to have a -;; port-mapping record that keeps a count of how many -;; handlers (maybe via a promise?) -(define (port-mapping-empty? port-mapping) - "Is this port mapping empty?" - (eq? (hash-count (const #t) port-mapping) 0)) - -(define (port-mapping-non-empty? port-mapping) - "Whether this port-mapping contains any elements" - (not (port-mapping-empty? port-mapping))) - - ;;; Request to run stuff ;;; ==================== @@ -261,18 +358,156 @@ (proc run-request-proc) (when run-request-when)) -(define* (run proc #:optional when) +(define* (run-it proc #:optional when) + "Make a request to run PROC (possibly at WHEN)" (make-run-request proc when)) (define-syntax-rule (wrap body ...) + "Wrap contents in a procedure" (lambda () body ...)) -(define-syntax-rule (run-wrap body ...) - (run (wrap body ...))) +;; @@: Do we really want `body ...' here? +;; what about just `body'? +(define-syntax-rule (run body ...) + "Run everything in BODY but wrap in a convenient procedure" + (make-run-request (wrap body ...) #f)) + +(define-syntax-rule (run-at body ... when) + "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))) + + +;; A request to set up a port with at least one of read, write, except +;; handling processes + +(define-record-type + (make-port-request-intern port read write except) + port-request? + (port port-request-port) + (read port-request-read) + (write port-request-write) + (except port-request-except)) + +(define* (make-port-request port #:key read write except) + (if (not (or read write except)) + (throw 'no-port-handler-given "No port handler given.\n")) + (make-port-request-intern port read write except)) + +(define port-request make-port-request) + + + +;;; Asynchronous escape to run things +;;; ================================= + +;; The future's in futures + +(define (make-future call-first on-success on-fail on-error) + ;; TODO: add error stuff here + (lambda () + (let ((call-result (call-first))) + ;; queue up calling the + (run (on-success call-result))))) + +(define (agenda-on-error agenda) + (const #f)) + +(define (agenda-on-fail agenda) + (const #f)) + +(define* (request-future call-first on-success + #:key + (agenda (%current-agenda)) + (on-fail (agenda-on-fail agenda)) + (on-error (agenda-on-error agenda)) + (when #f)) + ;; TODO: error handling + ;; do we need some distinction between expected, catchable errors, + ;; and unexpected, uncatchable ones? Probably...? + (make-run-request + (make-future call-first on-success on-fail on-error) + when)) + +(define-syntax-rule (%sync async-request) + "Run BODY asynchronously at a prompt, passing args to make-future. + +Pronounced `eight-sync' despite the spelling. + +%sync was chosen because (async) was already taken and could lead to +errors, and this version of asynchronous code uses a prompt, so the `a' +character becomes a `%' prompt! :) + +The % and 8 characters kind of look similar... hence this library's +name! (That, and the pun 'eight-synchronous' programming.) +There are 8sync aliases if you prefer that name." + (abort-to-prompt (current-agenda-prompt) + async-request)) + +(define-syntax-rule (8sync args ...) + "Alias for %sync" + (%sync args ...)) + +;; Async port request and run-request meta-requests +(define (make-async-request proc) + "Wrap PROC in an async-request + +The purpose of this is to make sure that users don't accidentally +return the wrong thing via (8sync) and trip themselves up." + (cons '*async-request* proc)) + +(define (setup-async-request resume-kont async-request) + "Complete an async request for agenda-run-once's continuation handling" + (match async-request + (('*async-request* . async-setup-proc) + (async-setup-proc resume-kont)) + ;; TODO: deliver more helpful errors depending on what the user + ;; returned + (_ (throw 'invalid-async-request + "Invalid request passed back via an (%sync) procedure." + async-request)))) + +(define-syntax-rule (%run body ...) + (%run-at body ... #f)) + +(define-syntax-rule (%run-at body ... when) + (make-async-request + (lambda (kont) + (make-run-request + (wrap + (kont + (begin body ...))) + when)))) + +(define-syntax-rule (%run-delay body ... delay-time) + (%run-at body ... (tdelta delay-time))) + +(define-syntax-rule (%port-request add-this-port port-request-args ...) + (make-async-request + (lambda (kont) + (list (make-port-request port-request-args ...) + (make-run-request kont))))) + +;; TODO +(define-syntax-rule (%run-with-return return body ...) + (make-async-request + (lambda (kont) + (let ((return kont)) + (lambda () + body ...))))) + +;; Aliases +(define-syntax-rule (8run args ...) (%run args ...)) +(define-syntax-rule (8run-at args ...) (%run-at args ...)) +(define-syntax-rule (8run-delay args ...) (%run-delay args ...)) +(define-syntax-rule (8port-request args ...) (%port-request args ...)) -(define-syntax-rule (run-wrap-at body ... when) - (run (wrap body ...) when)) ;;; Execution of agenda, and current agenda @@ -280,28 +515,135 @@ (define %current-agenda (make-parameter #f)) -(define* (start-agenda agenda #:optional stop-condition) +(define (update-agenda-from-select! agenda) + "Potentially (select) on ports specified in agenda, adding items to queue" + (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 (agenda-handle-port-request! agenda port-request) + "Update an agenda for a port-request" + (define (handle-selector request-selector port-map-selector) + (if (request-selector port-request) + (hash-set! (port-map-selector agenda) + (port-request-port port-request) + (request-selector port-request)))) + (handle-selector port-request-read agenda-read-port-map) + (handle-selector port-request-write agenda-write-port-map) + (handle-selector port-request-except agenda-except-port-map)) + + +(define* (start-agenda agenda + #:key stop-condition + (get-time gettimeofday) + (handle-ports update-agenda-from-select!)) + ;; TODO: Document fields + "Start up the AGENDA" (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 - (parameterize ((%current-agenda agenda)) - (agenda-run-once agenda)))) + (agenda-run-once agenda))) (if (and stop-condition (stop-condition agenda)) 'done - (loop new-agenda))))) + (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)))))) (define (agenda-run-once agenda) "Run once through the agenda, and produce a new agenda based on the results" (define (call-proc proc) (call-with-prompt - (agenda-prompt-tag agenda) - (lambda () - (proc)) - ;; TODO - (lambda (k) k))) + (agenda-prompt-tag agenda) + (lambda () + (parameterize ((%current-agenda agenda)) + (proc))) + (lambda (kont async-request) + (setup-async-request kont async-request)))) (let ((queue (agenda-queue agenda)) (next-queue (make-q))) @@ -310,24 +652,35 @@ 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-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)))))))) + (define (handle-individual result) + (match result + ((? run-request? new-proc) + (enqueue new-proc)) + ((? port-request? port-request) + (agenda-handle-port-request! agenda port-request)) + ;; do nothing + (_ #f))) ;; @@: We might support delay-wrapped procedures here (match proc-result - ;; TODO: replace procedure with something that indicates - ;; intent to run. Use a (run foo) procedure - ((? run-request? new-proc) - (enqueue new-proc)) - (((? run-request? new-procs) ...) - (for-each - (lambda (new-proc) - (enqueue new-proc)) - new-procs)) - ;; do nothing - (_ #f)))) - ;; TODO: Selecting on ports would happen here? + ((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)))