quit patch

audio-placed-player.rkt

@@ -97,6 +97,11 @@
 
     (define (get)
       (uni-channel-get ch-in))
+
+    (define (close-and-wait ch)
+      (when ch
+        (uni-channel-close ch)
+        (uni-channel-wait ch)))
           
     (define (audio-read-worker ao-dec file-id)
       (set! feeding-audio #t)
@@ -481,11 +486,17 @@
                                          ))])
 
            (cond
-             ((eq? cmd 'quit) (do-rpc
-                               (stop-and-cleanup)
-                               (set! player-state 'quit)
-                               (state "quit" evt 'force)
-                               '(quit)))
+             ((eq? cmd 'quit)
+              ;; Quit is the one RPC where the acknowledgement must be written
+              ;; before the worker starts tearing down its audio state and stdio
+              ;; transport.  For port-based uni-channels, put is asynchronous:
+              ;; close-and-wait makes sure the queued '(quit) has actually been
+              ;; written and flushed before the process exits.
+              (put '(quit))
+              (close-and-wait ch-out)
+              (stop-and-cleanup)
+              (set! player-state 'quit)
+              (close-and-wait ch-evt))
              ((eq?  cmd 'init) (do-rpc
                                 (set! ch-out (->uni-channel (cadr data)))
                                 (set! ch-evt (->uni-channel (caddr data)))