-(define-module (loopy agenda)
+;; Copyright (C) 2015 Christopher Allan Webber <cwebber@dustycloud.org>
+
+;; 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)
#:use-module (ice-9 match)
#:use-module (ice-9 receive)
- #:export (make-agenda
- agenda?
+ #: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>
+ make-time-segment time-segment?
time-segment-time time-segment-queue
- time-< time-= time-<=
+ time< time= time<= time-delta+
+ time-minus time-plus
- make-schedule
+ <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!
+
+ %sync 8sync
+
+ <run-request>
+ make-run-request run-request?
+ run-request-proc run-request-when
- schedule-segments-until schedule-extract-until!
+ <port-request>
+ make-port-request port-request port-request?
+ port-request-port
+ port-request-read port-request-write port-request-except
- make-port-mapping
- port-mapping-set! port-mapping-remove!
- port-mapping-empty? port-mapping-non-empty?
+ 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))
;;; 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
+ 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))))
\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)
(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)
(_ (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)
#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 <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 0))
+ "Make a <time-delta> 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 <schedule>
(make-schedule-intern segments)
(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
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?
(loop (schedule-segments schedule)))))
(define (schedule-empty? schedule)
+ "Check if the SCHEDULE is currently empty"
(eq? (schedule-segments schedule) '()))
-(define (schedule-segments-until schedule time)
+(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)))
(define (schedule-extract-until! schedule time)
"Extract all segments until TIME from SCHEDULE, and pop old segments off"
(receive (segments-before segments-after)
- (schedule-split-segments-until schedule time)
+ (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))
-
-(define* (port-mapping-set! port-mapping port #:optional read write except)
- "Sets port-mapping for reader / writer / exception handlers"
+\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-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 ...))
+
+;; @@: 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 <port-request>
+ (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-handlers-given "No handlers given for port" port))
- (hashq-set! port-mapping port
- `#(,read ,write ,except)))
+ (throw 'no-port-handler-given "No port handler given.\n"))
+ (make-port-request-intern port read write except))
-(define (port-mapping-remove! port-mapping port)
- (hashq-remove! port-mapping port))
+(define port-request make-port-request)
-;; 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)))
+\f
+;;; 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 ...))
\f
(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)))
(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-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
- ((? procedure? new-proc)
- (enqueue new-proc))
- (((? procedure? 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)))
projects / 8sync.git / blobdiff