;;; 8sync --- Asynchronous programming for Guile
-;;; Copyright (C) 2015 Christopher Allan Webber <cwebber@dustycloud.org>
+;;; Copyright (C) 2015, 2016 Christopher Allan Webber <cwebber@dustycloud.org>
;;;
;;; This file is part of 8sync.
;;;
#: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
schedule-segments-split schedule-extract-until!
add-segments-contents-to-queue!
- %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 wrap-apply run run-at run-delay
- %run %run-at %run-delay %port-request
- %8sync-run %8sync-run-at %8sync-run-delay %8sync-port
+ 8sync-delay
+ 8sync-run 8sync-run-at 8sync-run-delay
+ 8sync
+ 8sleep
- catch-8sync catch-%8sync
-
;; used for introspecting the error, but a method for making
;; is not exposed
wrapped-exception?
print-error-and-continue
+ 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?
(define-immutable-record-type <agenda>
(make-agenda-intern queue prompt-tag
- read-port-map write-port-map except-port-map
+ read-port-map write-port-map
schedule time catch-handler pre-unwind-handler)
agenda?
(queue 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)
(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 #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
+ read-port-map write-port-map
schedule time
catch-handler pre-unwind-handler))
(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-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 <port-remove-request>
- (make-port-remove-request port)
- port-remove-request?
- (port port-remove-request-port))
-
-(define port-remove-request make-port-remove-request)
-
-
\f
;;; Asynchronous escape to run things
;;; =================================
-(define-syntax-rule (%8sync async-request)
- "Run BODY asynchronously at a prompt, passing args to make-future.
-
-Runs things asynchronously (8synchronously?)"
- (propagate-%async-exceptions
- (abort-to-prompt (current-agenda-prompt)
- async-request)))
+(define-syntax-rule (8sync-abort-to-prompt async-request)
+ (abort-to-prompt (current-agenda-prompt)
+ async-request))
;; 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."
+return the wrong thing via (8sync) and trip themselves up."
(cons '*async-request* proc))
(define (setup-async-request resume-kont async-request)
;; TODO: deliver more helpful errors depending on what the user
;; returned
(_ (throw 'invalid-async-request
- "Invalid request passed back via an (%8sync) procedure."
+ "Invalid request passed back via an (8sync) procedure."
async-request))))
(define-record-type <wrapped-exception>
(wrapped-exception-stacks body-result))
body-result)))
-(define-syntax-rule (%run body ...)
- (%run-at body ... #f))
-
-(define-syntax-rule (%run-at body ... when)
- ;; Send an asynchronous request to apply a continuation to the
- ;; following function, then handle that as a request to the agenda
- (make-async-request
- (lambda (kont)
- ;; We're making a run request
- (make-run-request
- ;; Wrapping the following execution to run...
- (wrap
- ;; Once we get the result from the inner part, we'll resume
- ;; this continuation, but first
- ;; @@: Is this running immediately, or queueing the result
- ;; after evaluation for the next agenda tick? It looks
- ;; like evaluating immediately. Is that what we want?
- (kont
- ;; Any unhandled errors are caught
- (let ((exception-stack #f))
- (catch #t
- ;; Run the actual code the user requested
- (lambda ()
- body ...)
- ;; If something bad happened and we didn't catch it,
- ;; we'll wrap it up in such a way that the continuation
- ;; can address it
- (lambda (key . args)
- (cond
- ((eq? key '8sync-caught-error)
- (match args
- ((orig-key orig-args orig-stacks)
- (make-wrapped-exception
- orig-key orig-args
- (cons exception-stack orig-stacks)))))
- (else
- (make-wrapped-exception key args
- (list exception-stack)))))
- (lambda _
- (set! exception-stack (make-stack #t 1 0)))))))
- when))))
-
-(define-syntax-rule (%run-delay body ... delay-time)
- (%run-at body ... (tdelta delay-time)))
-
-(define-syntax-rule (%port-request port port-request-args ...)
- (make-async-request
- (lambda (kont)
- (list (make-port-request port port-request-args ...)
- (make-run-request kont)))))
-
-(define-syntax-rule (%port-remove-request port)
- (make-async-request
- (lambda (kont)
- (list (make-port-remove-request port)
- (make-run-request kont)))))
-
-
-;; Sugar
-(define-syntax-rule (%8sync-run rest ...)
- "Sugar for (%8sync (%run ...))"
- (%8sync (%run rest ...)))
-
-(define-syntax-rule (%8sync-run-at rest ...)
- "Sugar for (%8sync (%run-at ...))"
- (%8sync (%run-at rest ...)))
-
-(define-syntax-rule (%8sync-run-delay rest ...)
- "Sugar for (%8sync (%run-delay ...))"
- (%8sync (%run-delay rest ...)))
-
-(define-syntax-rule (%8sync-port rest ...)
- "Sugar for (%8sync (%port-request ...))"
- (%8sync (%port-request rest ...)))
+(define-syntax-rule (8sync-run body ...)
+ (8sync-run-at body ... #f))
+(define-syntax-rule (8sync-run-at body ... when)
+ (propagate-%async-exceptions
+ (8sync-abort-to-prompt
+ ;; Send an asynchronous request to apply a continuation to the
+ ;; following function, then handle that as a request to the agenda
+ (make-async-request
+ (lambda (kont)
+ ;; We're making a run request
+ (make-run-request
+ ;; Wrapping the following execution to run...
+ (wrap
+ ;; Once we get the result from the inner part, we'll resume
+ ;; this continuation, but first
+ ;; @@: Is this running immediately, or queueing the result
+ ;; after evaluation for the next agenda tick? It looks
+ ;; like evaluating immediately. Is that what we want?
+ (kont
+ ;; Any unhandled errors are caught
+ (let ((exception-stack #f))
+ (catch #t
+ ;; Run the actual code the user requested
+ (lambda ()
+ body ...)
+ ;; If something bad happened and we didn't catch it,
+ ;; we'll wrap it up in such a way that the continuation
+ ;; can address it
+ (lambda (key . args)
+ (cond
+ ((eq? key '8sync-caught-error)
+ (match args
+ ((orig-key orig-args orig-stacks)
+ (make-wrapped-exception
+ orig-key orig-args
+ (cons exception-stack orig-stacks)))))
+ (else
+ (make-wrapped-exception key args
+ (list exception-stack)))))
+ (lambda _
+ (set! exception-stack (make-stack #t 1 0)))))))
+ when))))))
+
+(define-syntax-rule (8sync-run-delay body ... delay-time)
+ (8sync-run-at body ... (tdelta delay-time)))
+
+(define-syntax-rule (8sync-delay args ...)
+ (8sync-run-delay args ...))
;; TODO: Write (%run-immediately)
-;; TODO
-(define-syntax-rule (%run-with-return return body ...)
- (make-async-request
- (lambda (kont)
- (let ((return kont))
- (lambda ()
- body ...)))))
-
-(define-syntax-rule (catch-8sync exp (handler-key handler) ...)
- (catch '8sync-caught-error
- (lambda ()
- exp)
- (lambda (_ orig-key orig-args orig-stacks)
- (cond
- ((or (eq? handler-key #t)
- (eq? orig-key handler-key))
- (apply handler orig-stacks orig-args)) ...
- (else (raise '8sync-caught-error
- orig-key orig-args orig-stacks))))))
-
-;; Alias...?
-(define-syntax-rule (catch-%8sync rest ...)
- (catch-8sync rest ...))
+(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
+ ;; What's with returning #f to kont?
+ ;; Otherwise we sometimes get errors like
+ ;; "Zero values returned to single-valued continuation""
+ (wrap (kont #f)) #f)
+ (make-run-request (lambda () body) #f))))))
+
+;; This is sugar... and could probably be considerably
+;; simplified and optimized. But whatever.
+(define-syntax-rule (8sleep time)
+ (8sync-delay 'no-op time))
\f
(define %current-agenda (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)
(lambda ()
(select (hash-keys (agenda-read-port-map agenda))
(hash-keys (agenda-write-port-map agenda))
- (hash-keys (agenda-except-port-map agenda))
+ '()
sec usec))
(lambda (key . rest-args)
(match rest-args
(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)
- ;; @@: Should we remove if #f?
- (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 (agenda-handle-port-remove-request! agenda port-remove-request)
- "Update an agenda for a port-remove-request"
- (let ((port (port-remove-request-port port-remove-request)))
- (hash-remove! (agenda-read-port-map agenda) port)
- (hash-remove! (agenda-write-port-map agenda) port)
- (hash-remove! (agenda-except-port-map agenda) port)))
+(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* (start-agenda agenda
- #:key stop-condition
+ #: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!))
+ (handle-ports update-agenda-from-select!)
+ ;; For live hacking madness, etc
+ (post-run-hook #f))
;; TODO: Document fields
"Start up the AGENDA"
(let loop ((agenda agenda))
;; 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.
+ (if post-run-hook
+ (post-run-hook agenda))
(if (and stop-condition (stop-condition agenda))
'done
(let* ((agenda
(agenda-queue agenda))
(loop agenda))))))
+
(define (print-error-and-continue key . args)
"Frequently used as pre-unwind-handler for agenda"
(cond
(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"
(call-with-prompt
(agenda-prompt-tag agenda)
(lambda ()
- (parameterize ((%current-agenda agenda))
+ (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))
(match result
((? run-request? new-proc)
(enqueue new-proc))
- ((? port-request? port-request)
- (agenda-handle-port-request! agenda port-request))
- ((? port-remove-request? port-remove-request)
- (agenda-handle-port-remove-request! agenda port-remove-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
projects / 8sync.git / blobdiff