-;; 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)
+;;; 8sync --- Asynchronous programming for Guile
+;;; Copyright (C) 2015, 2016 Christopher Allan Webber <cwebber@dustycloud.org>
+;;;
+;;; This file is part of 8sync.
+;;;
+;;; 8sync 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.
+;;;
+;;; 8sync 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 8sync. If not, see <http://www.gnu.org/licenses/>.
+
+(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)
+ #:use-module (ice-9 suspendable-ports)
#:export (<agenda>
make-agenda agenda?
agenda-queue agenda-prompt-tag
- agenda-read-port-map agenda-write-port-map agenda-except-port-map
+ agenda-read-port-map agenda-write-port-map
agenda-schedule
make-async-prompt-tag
- <time-segment>
- make-time-segment time-segment?
- time-segment-time time-segment-queue
-
- time< time= time<= time-delta+
- time-minus time-plus
-
- <time-delta>
- make-time-delta tdelta time-delta?
- time-delta-sec time-delta-usec
+ list->q make-q*
<schedule>
make-schedule schedule?
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
- <port-request>
- 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
+ run-it wrap wrap-apply run run-at run-delay
- %port-request %run %run-at %run-delay
- 8port-request 8run 8run-at 8run-delay
+ 8sync
+ 8sleep 8yield
- %current-agenda
- start-agenda agenda-run-once))
+ ;; used for introspecting the error, but a method for making
+ ;; is not exposed
+ wrapped-exception?
+ wrapped-exception-key wrapped-exception-args
+ wrapped-exception-stacks
-;; @@: Using immutable agendas here, so wouldn't it make sense to
-;; replace this queue stuff with using pfds based immutable queues?
+ print-error-and-continue
+
+ stop-on-nothing-to-do
+
+ %current-agenda-prompt
+ run-agenda agenda-run-once!))
\f
;;; Agenda definition
;;; 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 <agenda>
+;; TODO: Tear out the immutable agenda aspect until we're actually ready
+;; to use it.
+(define-record-type <agenda>
(make-agenda-intern queue prompt-tag
- read-port-map write-port-map except-port-map
- schedule time)
+ read-port-map write-port-map
+ 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)
- (except-port-map agenda-except-port-map)
(schedule agenda-schedule)
- (time agenda-time))
+ (catch-handler agenda-catch-handler)
+ (pre-unwind-handler agenda-pre-unwind-handler))
(define (make-async-prompt-tag)
"Make an async prompt tag for an agenda.
(prompt (make-prompt-tag))
(read-port-map (make-hash-table))
(write-port-map (make-hash-table))
- (except-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 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))))
-
+ read-port-map write-port-map
+ schedule catch-handler pre-unwind-handler))
+
+;; helper for making queues for an agenda
+(define (list->q lst)
+ "Makes a queue composed of LST items"
+ (let ((q (make-q)))
+ (for-each
+ (lambda (x)
+ (enq! q x))
+ lst)
+ q))
+
+(define (make-q* . args)
+ "Makes a queue and populates it with this invocation's ARGS"
+ (list->q args))
\f
;;; Schedule
(time time-segment-time)
(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)
- ;; 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 a time segment of TIME and QUEUE
(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)
-
+;; @@: 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."
(+ (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)))))
+ (- (cdr time1) (cdr time2)))))
+;; @@: Unused?
(define (time-plus time1 time2)
"Add TIME1 and TIME2"
(time-carry-correct
(cons (+ (car time1) (car time2))
- (+ (cdr time2) (cdr time2)))))
-
+ (+ (cdr time1) (cdr time2)))))
(define-record-type <schedule>
(make-schedule-intern segments)
;; 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"
(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"
(lambda ()
body ...))
+(define-syntax-rule (wrap-apply body)
+ "Wrap possibly multi-value function in a procedure, applies all arguments"
+ (lambda args
+ (apply body args)))
+
+
;; @@: Do we really want `body ...' here?
;; what about just `body'?
(define-syntax-rule (run body ...)
"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)))
-;; A request to set up a port with at least one of read, write, except
-;; handling processes
+;;; Procedures that are delimited continuations being resumed are
+;;; wrapped in a <kontinue>. 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 <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-port-handler-given "No port handler given.\n"))
- (make-port-request-intern port read write except))
-
-(define port-request make-port-request)
+(define-record-type <kontinue>
+ (kontinue kont)
+ kontinue?
+ (kont kontinue-kont))
\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)
+(define-syntax-rule (8sync-abort-to-prompt async-request)
+ (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
;; TODO: deliver more helpful errors depending on what the user
;; returned
(_ (throw 'invalid-async-request
- "Invalid request passed back via an (%sync) procedure."
+ "Invalid request passed back via an (8sync) 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 (8sync body ...)
+ "Run body asynchronously but ignore its result...
+forge ahead in our current function!"
+ (8sync-abort-to-prompt
+ (make-async-request
+ (lambda (kont)
+ (list (make-run-request
+ (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 secs)
+ "Like sleep, but asynchronous."
+ (8sync-abort-to-prompt
+ (make-async-request
+ (lambda (kont)
+ (make-run-request (kontinue kont) (delayed-time secs))))))
+
+;; Voluntarily yield execution
+(define (8yield)
+ "Voluntarily yield execution to the scheduler."
+ (8sync-abort-to-prompt
+ (make-async-request
+ (lambda (kont)
+ (make-run-request (kontinue kont) #f)))))
\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"
+ "Potentially (select) on ports specified in agenda, adding items to queue.
+
+Also handles sleeping when all we have to do is wait on the schedule."
(define (hash-keys hash)
(hash-map->list (lambda (k v) k) hash))
(define (get-wait-time)
((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)
;; 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))))
+ (catch 'system-error
+ (lambda ()
+ (select (hash-keys (agenda-read-port-map agenda))
+ (hash-keys (agenda-write-port-map agenda))
+ '()
+ sec usec))
+ (lambda (key . rest-args)
+ (match rest-args
+ ((_ _ _ (EINTR))
+ '(() () ()))
+ (_ (error "Unhandled error in select!" key rest-args))))))))
(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))
+ (define proc (hashq-ref port-map port))
+ ;; Now that we've selected on this port, it can be removed
+ (hashq-remove! port-map port)
+ (cons proc prev))
initial-procs
ports)))
(match (do-select)
- ((read-ports write-ports except-ports)
- ;; @@: Come on, we can do better than append ;P
+ ((read-ports write-ports except-ports) ; except-ports not used
((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)))
+ (agenda-write-port-map agenda)))
'()))))
(define (update-agenda)
(let ((procs-to-run (get-procs-to-run))
(selector agenda))
0)))
(or (has-items? agenda-read-port-map)
- (has-items? agenda-write-port-map)
- (has-items? agenda-except-port-map)))
+ (has-items? agenda-write-port-map)))
- (if (ports-to-select?)
+ (if (or (ports-to-select?)
+ ;; select doubles as sleep...
+ (not (schedule-empty? (agenda-schedule agenda))))
(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!))
+(define-record-type <read-request>
+ (make-read-request port proc)
+ read-request?
+ (port read-request-port)
+ (proc read-request-proc))
+
+(define-record-type <write-request>
+ (make-write-request port proc)
+ write-request?
+ (port write-request-port)
+ (proc write-request-proc))
+
+(define (agenda-handle-read-request! agenda read-request)
+ "Handle <read-request>, which is a request to add this port to the poll/select
+on suspendable ports."
+ (hashq-set! (agenda-read-port-map agenda)
+ (read-request-port read-request)
+ (read-request-proc read-request)))
+
+(define (agenda-handle-write-request! agenda write-request)
+ (hashq-set! (agenda-write-port-map agenda)
+ (write-request-port write-request)
+ (write-request-proc write-request)))
+
+(define (stop-on-nothing-to-do agenda)
+ (and (q-empty? (agenda-queue agenda))
+ (schedule-empty? (agenda-schedule agenda))
+ (= 0 (hash-count (const #t) (agenda-read-port-map agenda)))
+ (= 0 (hash-count (const #t) (agenda-write-port-map agenda)))))
+
+
+(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)))
- (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))))))
-
-(define (agenda-run-once agenda)
+ (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))))
+ 'done)
+
+(define (print-error-and-continue key . args)
+ "Frequently used as pre-unwind-handler for agenda"
+ (cond
+ ((eq? key '8sync-caught-error)
+ (match args
+ ((orig-key orig-args stacks)
+ (display "\n*** Caught async exception. ***\n")
+ (format (current-error-port)
+ "* Original key '~s and arguments: ~s *\n"
+ orig-key orig-args)
+ (display "* Caught stacks below (ending with original) *\n\n")
+ (for-each
+ (lambda (s)
+ (display-backtrace s (current-error-port))
+ (newline (current-error-port)))
+ stacks))))
+ (else
+ (format (current-error-port)
+ "\n*** Caught exception with key '~s and arguments: ~s ***\n"
+ key args)
+ (display-backtrace (make-stack #t 1 0)
+ (current-error-port))
+ (newline (current-error-port)))))
+
+(define-syntax-rule (maybe-catch-all (catch-handler pre-unwind-handler)
+ body ...)
+ (if (or catch-handler pre-unwind-handler)
+ (catch
+ #t
+ (lambda ()
+ body ...)
+ (or catch-handler (lambda _ #f))
+ (or pre-unwind-handler (lambda _ #f)))
+ (begin body ...)))
+
+(define (wait-for-readable port)
+ (8sync-abort-to-prompt
+ (make-async-request
+ (lambda (kont)
+ (make-read-request port (wrap (kont #f)))))))
+
+(define (wait-for-writable port)
+ (8sync-abort-to-prompt
+ (make-async-request
+ (lambda (kont)
+ (make-write-request port (wrap (kont #f)))))))
+
+(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))
- (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))))
(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
((? run-request? new-proc)
(enqueue new-proc))
- ((? port-request? port-request)
- (agenda-handle-port-request! agenda port-request))
+ ((? read-request? read-request)
+ (agenda-handle-read-request! agenda read-request))
+ ((? write-request? write-request)
+ (agenda-handle-write-request! agenda write-request))
;; do nothing
+ ;; Remember, we don't throw an error here because procedures can
+ ;; return a run request, eg with run-it, at the end of their
+ ;; evaluation to keep looping.
+ ;; @@: Though is this really a useful feature?
(_ #f)))
;; @@: We might support delay-wrapped procedures here
(match proc-result
((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)))
projects / 8sync.git / blobdiff