nse/client: Add a 'disconnected' callback.

* gnu/gnunet/nse/client.scm
  (connect): Add 'disconnected' optional keyword argument.  Document
  it.
  (connect)[error-handler]: In case of input:regular-end-of-file and
  input:premature-end-of-file, call 'disconnected'.
  (<server>)[disconnected]: New field.
* tests/network-size.scm
  ("notify disconnected after end-of-file, after 'connected'"):
  New test.

1 files changed, 12 insertions, 7 deletions

diff --git a/gnu/gnunet/nse/client.scm b/gnu/gnunet/nse/client.scm
index 5442c7c..17c16a3 100644
--- a/gnu/gnunet/nse/client.scm
+++ b/gnu/gnunet/nse/client.scm
@@ -78,8 +78,7 @@
               (immutable mq nse-mq) ; message queue
               (immutable config server-config)
               (immutable connected-callback server-connected-callback)
-                                        ; TODO
-                                        ; (immutable disconnected-callback nse-disconnected-callback)
+              (immutable disconnected-callback server-disconnected-callback)
               (immutable estimate-update-callback server-update-callback)))
 
     (define (estimate server)
@@ -118,14 +117,19 @@ Maybe +inf.0 as well?"
 timestamp."
       (%estimate:timestamp estimate))
 
-    (define* (connect config #:key updated connected (spawn spawn-fiber))
+    (define* (connect config #:key updated connected disconnected
+                      (spawn spawn-fiber))
       "Connect to the NSE service in the background.
 
 When connected, the thunk @var{connected} is called and estimates
 will become available (but possibly not immediately).  When a new
 estimate is available, the procedure @var{updated} is called.  This
-procedure should accept the new estimate.  The procedures @var{updated}
-and @var{connected} are optional."
+procedure should accept the new estimate.   When disconnected, the
+thunk @code{disconnected} and updates will be (temporarily) unavailable,
+until connected again.  It is possible for @var{updated} to be called
+shortly after calling @var{disconnected}.
+
+The procedures @var{updated}, @var{connected} and @var{disconnected} are optional."
       (define estimate/box (make-atomic-box #f))
       (define (handle-estimate! estimate-slice)
         (define estimate
@@ -161,8 +165,9 @@ and @var{connected} are optional."
            (when connected (connected)))
           ;; TODO this means the server has closed the connection ...
           ;; ---> reconnect?
-          ((input:regular-end-of-file)
+          ((input:regular-end-of-file input:premature-end-of-file)
+           (when disconnected (disconnected))
            (values))))
       (define mq (connect/fibers config "nse" handlers error-handler
                                  #:spawn spawn))
-      (%make-server estimate/box mq config connected updated))))
+      (%make-server estimate/box mq config connected disconnected updated))))