Handle termination of rktwebview_prg through alive event mechanism.

racket-webview-qt.rkt

@@ -569,6 +569,14 @@
   )
 |#
 
+(define alive-error-event -94328)
+
+(define (close-down-on-alive-error)
+  (rkt-webview-exit #f
+                    "rktwebview_prg has stopped working, cannot continue"
+                    )  ; close without closing windows
+  )
+
 (define (start-event-processing)
    (thread (λ ()
      (letrec
@@ -589,9 +597,12 @@
                                                              _string*/utf-8))
                                    )
                               (rkt_webview_free_data rkt-evt)
+                              ;(displayln (format "~a ~a" wv evt))
+                              (if (= wv alive-error-event)
+                                  (close-down-on-alive-error)
                                   (let ((cb (hash-ref evt-cb-hash wv #f)))
                                     (unless (eq? cb #f)
-                                  (cb evt))))))
+                                      (cb evt)))))))
                       (set! waiting (- waiting 1))
                       )
                )
@@ -798,14 +809,24 @@
           #f
           #t)))
 
-(define (rkt-webview-exit)
+(define (rkt-webview-exit . args)
+  (let ((cl-w (if (null? args) #f (car args)))
+        (msg (if (null? args) #f
+                 (if (null? (cdr args))
+                     #f
+                     (cadr args))))
+        )
+    (when cl-w
       (let ((open-windows (hash->list rkt-wv-store)))
         (for-each (λ (kv)
                     (let ((win (car kv))
                           (handle (cdr kv)))
                       (rkt-webview-close handle)))
-              open-windows))
+                  open-windows)))
     (rkt_webview_cleanup)
+    (unless (eq? msg #f)
+      (error msg))
+    )
     (stop-event-processing)
   )