actors: Properly autoreply to replies; make reply-message-wait work.

* 8sync/systems/actors.scm (hive-process-message): Enable prompt even when
  resuming coroutines.
  Enable autoreply when resuming coroutines.
  (send-message-wait, reply-message-wait): Rename agenda-prompt variable to
  abort-to, which makes more sense.

diff --git a/8sync/systems/actors.scm b/8sync/systems/actors.scm
index 51a6e50c88abfee680426b3356d2b159f0e00882..8f00d570d9f5880d901a6063334e59e047d3f4d0 100644 (file)
--- a/8sync/systems/actors.scm
+++ b/8sync/systems/actors.scm
@@ -203,12 +203,12 @@ If key not found and DFLT not provided, throw an error."
 (define (send-message-wait from-actor to-id action . message-body-args)
   "Send a message from an actor to another, but wait until we get a response"
   (let* ((hive (actor-hive from-actor))
-         (agenda-prompt (hive-prompt (actor-hive from-actor)))
+         (abort-to (hive-prompt (actor-hive from-actor)))
          (message (make-message (hive-gen-message-id hive) to-id
                                 (actor-id from-actor) action
                                 (kwarg-list-to-alist message-body-args)
                                 #:wants-reply #t)))
-    (abort-to-prompt agenda-prompt from-actor message)))
+    (abort-to-prompt abort-to from-actor message)))
 
 ;; TODO: Intelligently ~propagate(ish) errors on -wait functions.
 ;;   We might have `send-message-wait-brazen' to allow callers to
@@ -232,14 +232,14 @@ If key not found and DFLT not provided, throw an error."
   "Reply to a messsage, but wait until we get a response"
   (set-message-replied! original-message #t)
   (let* ((hive (actor-hive from-actor))
-         (agenda-prompt (hive-prompt (actor-hive from-actor)))
+         (abort-to (hive-prompt (actor-hive from-actor)))
          (new-message (make-message (hive-gen-message-id hive)
                                     (message-from original-message)
                                     (actor-id from-actor) '*reply*
                                     (kwarg-list-to-alist message-body-args)
                                     #:wants-reply #t
                                     #:in-reply-to (message-id original-message))))
-    (abort-to-prompt agenda-prompt from-actor new-message)))
+    (abort-to-prompt abort-to from-actor new-message)))
 
 
 \f
@@ -445,7 +445,15 @@ more compact following syntax:
 
 (define-method (hive-process-message (hive <hive>) message)
   "Handle one message, or forward it via an ambassador"
-  (define (process-local-message)
+  (define (maybe-autoreply actor)
+    ;; Possibly autoreply
+    (if (message-needs-reply message)
+        ;; @@: Should we give *autoreply* as the action instead of *reply*?
+        (reply-message actor message
+                       #:*auto-reply* #t)))
+
+  (define (resolve-actor-to)
+    "Get the actor the message was aimed at"
     (let ((actor (hive-resolve-local-actor hive (message-to message))))
       (if (not actor)
           (throw 'actor-not-found
@@ -454,46 +462,56 @@ more compact following syntax:
                          (address->string (message-from message))
                          (address->string (message-to message)))
                  message))
-      (call-with-prompt (hive-prompt hive)
-        (lambda ()
-          (define message-handler (actor-message-handler actor))
-          ;; @@: Should a more general error handling happen here?
-          (let ((result
-                 (message-handler actor message)))
-            ;; Possibly autoreply
-            (if (message-needs-reply message)
-                ;; @@: Should we give *autoreply* as the action instead of *reply*?
-                (reply-message actor message
-                               #:*auto-reply* #t))
-            ;; Returning result allows actors to possibly make a run-request
-            ;; at the end of handling a message.
-            ;; ... We do want that, right?
-            result))
+      actor))
+
+  (define (call-catching-coroutine thunk)
+    (call-with-prompt (hive-prompt hive)
+      thunk
+      (lambda (kont actor message)
+        (let ((hive (actor-hive actor)))
+          ;; Register the coroutine
+          (hash-set! (hive-waiting-coroutines hive)
+                     (message-id message)
+                     (cons (actor-id actor) kont))
+          ;; Send off the message
+          (8sync (hive-process-message hive message))))))
 
-        (lambda (kont actor message)
-          (let ((hive (actor-hive actor)))
-            ;; Register the coroutine
-            (hash-set! (hive-waiting-coroutines hive)
-                       (message-id message)
-                       (cons (actor-id actor) kont))
-            ;; Send off the message
-            (8sync (hive-process-message hive message)))))))
+  (define (process-local-message)
+    (let ((actor (resolve-actor-to)))
+      (call-catching-coroutine
+       (lambda ()
+         (define message-handler (actor-message-handler actor))
+         ;; @@: Should a more general error handling happen here?
+         (let ((result
+                (message-handler actor message)))
+           (maybe-autoreply actor)
+           ;; Returning result allows actors to possibly make a run-request
+           ;; at the end of handling a message.
+           ;; ... We do want that, right?
+           result)))))
 
   (define (resume-waiting-coroutine)
-    (match (hash-remove! (hive-waiting-coroutines hive)
-                         (message-in-reply-to message))
-      ((_ . (resume-actor-id . kont))
-       (if (not (equal? (message-to message)
-                        resume-actor-id))
-           (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
-                  #:message message))
-       (kont message))
-      (#f (throw 'no-waiting-coroutine
-                 "message in-reply-to tries to resume nonexistent coroutine"
-                 message))))
+    (call-catching-coroutine
+     (lambda ()
+       (match (hash-remove! (hive-waiting-coroutines hive)
+                            (message-in-reply-to message))
+         ((_ . (resume-actor-id . kont))
+          (if (not (equal? (message-to message)
+                           resume-actor-id))
+              (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
+                     #:message message))
+          (let (;; @@: How should we resolve resuming coroutines to actors who are
+                ;;   now gone?
+                (actor (resolve-actor-to))
+                (result (kont message)))
+            (maybe-autoreply actor)
+            result))
+         (#f (throw 'no-waiting-coroutine
+                    "message in-reply-to tries to resume nonexistent coroutine"
+                    message))))))
 
   (define (process-remote-message)
     ;; Find the ambassador