From 5fa0225a261a031fc8cd2988932e6a3e8f4528fb Mon Sep 17 00:00:00 2001 From: Christopher Allan Webber Date: Wed, 21 Dec 2016 17:00:43 -0600 Subject: [PATCH] actors: Move error propagation within <-wait; add <-wait*, <-reply-wait*. * 8sync/actors.scm (send-message): Rename xtra-params argument to send-options and use it in aborting to the hive prompt. (<-wait*, <-reply-wait*): New procedures. These allow for adding a send-options list as a first argument, including #:accept-errors. These also wrap call wait-maybe-handle-errors. (<-wait, <-reply-wait): Updated as thin wrappers around <-wait* and <-reply-wait*. (wait-maybe-handle-errors): New procedure. (): New record type. (hive-process-message): Update to accept send-options and make use of . Removes error handling, which now hapens in wait-maybe-handle-errors. --- 8sync/actors.scm | 92 +++++++++++++++++++++++++++++++----------------- 1 file changed, 60 insertions(+), 32 deletions(-) diff --git a/8sync/actors.scm b/8sync/actors.scm index b651d55..867e3d0 100644 --- a/8sync/actors.scm +++ b/8sync/actors.scm @@ -70,7 +70,7 @@ message-auto-reply? - <- <-wait <-reply <-reply-wait + <- <-wait <-wait* <-reply <-reply-wait <-reply-wait* call-with-message msg-receive msg-val @@ -170,7 +170,8 @@ ;; @@: Could we get rid of some of the conditional checks through ;; some macro-foo? -(define-inlinable (send-message xtra-params from-actor to-id action + +(define-inlinable (send-message send-options from-actor to-id action replying-to-message wants-reply? message-body-args) (if replying-to-message @@ -185,10 +186,13 @@ (if replying-to-message (message-id replying-to-message) #f)))) - ;; TODO: add xtra-params to both of these (if wants-reply? (abort-to-prompt (hive-prompt (actor-hive from-actor)) - from-actor new-message) + from-actor new-message send-options) + ;; @@: It might be that eventually we pass in send-options + ;; here too. Since <-wait and <-reply-wait are the only ones + ;; that use it yet, for now it kind of just makes things + ;; confusing. (8sync (hive-process-message hive new-message))))) @@ -197,10 +201,17 @@ (send-message '() from-actor to-id action #f #f message-body-args)) +(define (<-wait* send-options from-actor to-id action . message-body-args) + "Like <-wait, but allows extra parameters, for example whether to +#:accept-errors" + (apply wait-maybe-handle-errors + (send-message send-options from-actor to-id action + #f #t message-body-args) + send-options)) + (define (<-wait from-actor to-id action . message-body-args) "Send a message from an actor to another, but wait until we get a response" - (send-message '() from-actor to-id action - #f #t message-body-args)) + (apply <-wait* '() from-actor to-id action message-body-args)) ;; TODO: Intelligently ~propagate(ish) errors on -wait functions. ;; We might have `send-message-wait-brazen' to allow callers to @@ -217,10 +228,31 @@ (send-message '() from-actor (message-from original-message) '*auto-reply* original-message #f '())) +(define (<-reply-wait* send-options from-actor original-message + . message-body-args) + "Reply to a messsage, but wait until we get a response" + (apply wait-maybe-handle-errors + (send-message send-options from-actor + (message-from original-message) '*reply* + original-message #t message-body-args) + send-options)) + (define (<-reply-wait from-actor original-message . message-body-args) "Reply to a messsage, but wait until we get a response" - (send-message '() from-actor (message-from original-message) '*reply* - original-message #t message-body-args)) + (apply <-reply-wait* '() from-actor original-message message-body-args)) + +(define* (wait-maybe-handle-errors message + #:key accept-errors + #:allow-other-keys) + "Before returning a message to a waiting caller, see if we need to +raise an exception if an error." + (define action (message-action message)) + (cond ((and (eq? action '*error*) + (not accept-errors)) + (throw 'hive-unresumable-coroutine + "Won't resume coroutine; got an *error* as a reply" + #:message message)) + (else message))) @@ -438,6 +470,14 @@ to come after class definition." ;; unresumable continuation. (lambda () (hive-process-message hive new-message)))) +(define-record-type + (make-waiting-on-reply actor-id kont send-options) + waiting-on-reply? + (actor-id waiting-on-reply-actor-id) + (kont waiting-on-reply-kont) + (send-options waiting-on-reply-send-options)) + + (define-method (hive-process-message (hive ) message) "Handle one message, or forward it via an ambassador" (define (maybe-autoreply actor) @@ -487,11 +527,12 @@ to come after class definition." (8sync (queued-error-handling-thunk)))) (call-with-prompt (hive-prompt hive) call-catching-errors - (lambda (kont actor message) + (lambda (kont actor message send-options) ;; Register the coroutine (hash-set! (hive-waiting-coroutines hive) (message-id message) - (cons (actor-id actor) kont)) + (make-waiting-on-reply + (actor-id actor) kont send-options)) ;; Send off the message (8sync (hive-process-message hive message))))) @@ -513,42 +554,29 @@ to come after class definition." (define (resume-waiting-coroutine) (case (message-action message) ;; standard reply / auto-reply - ((*reply* *auto-reply*) + ((*reply* *auto-reply* *error*) (call-catching-coroutine (lambda () (match (hash-remove! (hive-waiting-coroutines hive) (message-in-reply-to message)) - ((_ . (resume-actor-id . kont)) + ((_ . waiting) (if (not (equal? (message-to message) - resume-actor-id)) + (waiting-on-reply-actor-id waiting))) (throw 'resuming-to-wrong-actor "Attempted to resume a coroutine to the wrong actor!" #:expected-actor-id (message-to message) - #:got-actor-id resume-actor-id + #:got-actor-id (waiting-on-reply-actor-id waiting) #:message message)) - (let (;; @@: How should we resolve resuming coroutines to actors who are - ;; now gone? - (actor (resolve-actor-to)) - (result (kont message))) + (let* (;; @@: How should we resolve resuming coroutines to actors who are + ;; now gone? + (actor (resolve-actor-to)) + (kont (waiting-on-reply-kont waiting)) + (result (kont message))) (maybe-autoreply actor) result)) (#f (throw 'no-waiting-coroutine "message in-reply-to tries to resume nonexistent coroutine" message)))))) - ;; Yikes, an error! - ((*error*) - ;; @@: Not what we want in the long run? - ;; What we'd *prefer* to do is to resume this message - ;; and throw an error inside the message handler - ;; (say, from send-mesage-wait), but that causes a SIGABRT (??!!) - (hash-remove! (hive-waiting-coroutines hive) - (message-in-reply-to message)) - (let ((explaination - (if (eq? (message-action message) '*reply*) - "Won't resume coroutine; got an *error* as a reply" - "Won't resume coroutine because action is not *reply*"))) - (throw 'hive-unresumable-coroutine - explaination #:message message))) ;; Unhandled action for a reply! (else (throw 'hive-unresumable-coroutine -- 2.31.1