added stuff for logging

2 files changed, 60 insertions, 20 deletions

diff --git a/README.xwidget b/README.xwidget
index db38e4cbd68..9cd741661bc 100644
--- a/README.xwidget
+++ b/README.xwidget
@@ -776,7 +776,7 @@ buffer. how do we catch these errors?
   thats not really an error either
 - xwidgets should now be proper lisp objects so you dont delete them
   you await their garbage collection. so therefore there can never be
-  invalid disploy specs
+  invalid display specs
 
 so turned out this got solved by using proper lisp objects for
 xwidgets. yay!
@@ -1527,3 +1527,34 @@ a callback that sets the buffer name automatically
 ** TODO unique buffer names
 the webkit xwidgets renames the buffer after load but not uniquely so
 it sometimes fails.
+** TODO kill the offscreen webkit xwidgets when last view killed
+The offscreen xwidgets is currently kept around even if the xwidgets
+views are all gone. this is a general problem and it requires actions
+on the behalf of the application to resolve.
+
+In the case of webkit it is currently possible to get errors like these:
+
+Debugger entered--Lisp error: (error "Selecting deleted buffer")
+  xwidget-webkit-callback(60925380 navigation-policy-decision-requested)
+  xwidget-event-handler()
+  call-interactively(xwidget-event-handler nil nil)
+
+
+because the last view is gone and the offscreen widgets is still
+generating events. 
+
+In the case of webkit it is okay to kill the offscreen widgets
+completely when the user kills the last view window because it would
+be unexpected by the user to see it pop up again. This is not true in
+the general case.
+
+** DONE xwidgets debugging log
+   CLOSED: [2012-01-23 Mon 14:32]
+currently theres a lot of debugging traces using "message" which is
+annoying. Instead put them in a separate trace buffer.
+(see xwidget-log)
+** TODO make garbage collect work for xwidgets
+when an xwidget is removed from xwidget-alist, and there are no other
+references(mostly views) the xwidget should be garbage collected.
+
+special finalization would go into gc_sweep()
diff --git a/lisp/xwidget.el b/lisp/xwidget.el
index a8fa84da37f..50e74add6a0 100644
--- a/lisp/xwidget.el
+++ b/lisp/xwidget.el
@@ -142,35 +142,44 @@ defaults to the string looking like a url around the cursor position."
 ;;since the xwidget can generate an event even if its offscreen
 ;;TODO this needs to use callbacks and consider different xw ev types
 (define-key (current-global-map) [xwidget-event] 'xwidget-event-handler)
+(defun xwidget-log ( &rest msg)
+  (let ( (buf  (get-buffer-create "*xwidget-log*")))
+    (save-excursion
+      (buffer-disable-undo buf)
+      (set-buffer buf)
+      (insert (apply  'format msg))
+      (insert "\n"))))
 
 (defun xwidget-event-handler ()
   "Receive xwidget event."
   (interactive)
-  (message "stuff happened to xwidget %S" last-input-event)
+  (xwidget-log "stuff happened to xwidget %S" last-input-event)
   (let*
       ((xwidget-event-type (nth 1 last-input-event))
        (xwidget (nth 2 last-input-event))
-       ;(xwidget-callback (xwidget-get xwidget 'callback));;TODO stopped working for some reason
+                                        ;(xwidget-callback (xwidget-get xwidget 'callback));;TODO stopped working for some reason
        )
-    ;(funcall  xwidget-callback xwidget xwidget-event-type)
+                                        ;(funcall  xwidget-callback xwidget xwidget-event-type)
     (funcall  'xwidget-webkit-callback xwidget xwidget-event-type)
     ))
 
 (defun xwidget-webkit-callback (xwidget xwidget-event-type)
   (save-excursion
-    (set-buffer (xwidget-buffer xwidget))
-    (let* ( (strarg  (nth 3 last-input-event)))
-      (cond ((eq xwidget-event-type 'document-load-finished)
-             (message "webkit finished loading: '%s'" (xwidget-webkit-get-title xwidget))
-             (xwidget-adjust-size-to-content xwidget)
-             (rename-buffer (format "*xwidget webkit: %s *" (xwidget-webkit-get-title xwidget)))
-             (pop-to-buffer (current-buffer))
-             )
-            
-            ((eq xwidget-event-type 'navigation-policy-decision-requested)
-             (if (string-match ".*#\\(.*\\)" strarg)
-                 (xwidget-webkit-show-id-or-named-element xwidget (match-string 1 strarg))))
-            (t (message "unhandled event:%s" xwidget-event-type))))))
+    (cond ( (buffer-live-p (xwidget-buffer xwidget))
+            (set-buffer (xwidget-buffer xwidget))
+            (let* ( (strarg  (nth 3 last-input-event)))
+              (cond ((eq xwidget-event-type 'document-load-finished)
+                     (xwidget-log "webkit finished loading: '%s'" (xwidget-webkit-get-title xwidget))
+                     (xwidget-adjust-size-to-content xwidget)
+                     (rename-buffer (format "*xwidget webkit: %s *" (xwidget-webkit-get-title xwidget)))
+                     (pop-to-buffer (current-buffer))
+                     )
+                    
+                    ((eq xwidget-event-type 'navigation-policy-decision-requested)
+                     (if (string-match ".*#\\(.*\\)" strarg)
+                         (xwidget-webkit-show-id-or-named-element xwidget (match-string 1 strarg))))
+                    (t (xwidget-log "unhandled event:%s" xwidget-event-type)))))
+          (t (xwidget-log "error: callback called for xwidget with dead buffer")))))
 
 (define-derived-mode xwidget-webkit-mode
   special-mode "xwidget-webkit" "xwidget webkit view mode"
@@ -272,7 +281,7 @@ Argument STR string."
   (let ((y 
          (string-to-number (xwidget-webkit-execute-script-rv xw (format "document.getElementsByName('%s')[0].getBoundingClientRect().top" element-name) 0))))
     ;;now we need to tell emacs to scroll the element into view. 
-    (message "scroll: %d" y)
+    (xwidget-log "scroll: %d" y)
     (set-window-vscroll (selected-window) y t))
   )
 
@@ -282,7 +291,7 @@ Argument STR string."
   (let ((y 
          (string-to-number (xwidget-webkit-execute-script-rv xw (format "document.getElementById('%s').getBoundingClientRect().top" element-id) 0))))
     ;;now we need to tell emacs to scroll the element into view. 
-    (message "scroll: %d" y)
+    (xwidget-log "scroll: %d" y)
     (set-window-vscroll (selected-window) y t))
   )
 
@@ -295,7 +304,7 @@ Argument STR string."
          (string-to-number (xwidget-webkit-execute-script-rv xw (format "document.getElementById('%s').getBoundingClientRect().top" element-id) 0)))
         (y3 (max y1 y2)))
     ;;now we need to tell emacs to scroll the element into view. 
-    (message "scroll: %d" y3)
+    (xwidget-log "scroll: %d" y3)
     (set-window-vscroll (selected-window) y3 t))
   )