X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/clg/blobdiff_plain/8755b1a5d37f2f4b853c01f0d8b121ab9ee4093a..0f152c4e3b437f6bbdf1c79e6f7c0433f121f550:/glib/gcallback.lisp

diff --git a/glib/gcallback.lisp b/glib/gcallback.lisp
index e421227..462f5aa 100644
--- a/glib/gcallback.lisp
+++ b/glib/gcallback.lisp
@@ -15,7 +15,7 @@
 ;; License along with this library; if not, write to the Free Software
 ;; Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
-;; $Id: gcallback.lisp,v 1.13 2004-11-07 01:23:38 espen Exp $
+;; $Id: gcallback.lisp,v 1.15 2004-12-04 00:29:57 espen Exp $
 
 (in-package "GLIB")
 
@@ -160,15 +160,16 @@ (defmethod signal-connect ((gobject gobject) signal function &key after object)
  function, or if :OBJECT is any other non NIL value, it is passed as the first 
  argument instead. If :AFTER is non NIL, the handler will be called after the 
  default handler of the signal."
-  (let ((callback-id
-	 (make-callback-closure
-	  (cond
-	   ((or (eq object t) (eq object gobject)) function)
-	   ((not object)
-	    #'(lambda (&rest args) (apply function (cdr args))))
-	   (t
-	    #'(lambda (&rest args) (apply function object (rest args))))))))
-    (signal-connect-closure gobject signal callback-id :after after)))
+  (when function
+    (let ((callback-id
+	   (make-callback-closure
+	    (cond
+	      ((or (eq object t) (eq object gobject)) function)
+	      ((not object)
+	       #'(lambda (&rest args) (apply function (cdr args))))
+	      (t
+	       #'(lambda (&rest args) (apply function object (rest args))))))))
+      (signal-connect-closure gobject signal callback-id :after after))))
 
 
 ;;; Message logging
@@ -181,3 +182,25 @@ (def-callback log-handler (c-call:void (domain c-call:c-string)
   (error "~A: ~A" domain message))
 
 (setf (extern-alien "log_handler" system-area-pointer) (callback log-handler))
+
+
+;;;; Convenient macros
+
+(defmacro def-callback-marshal (name (return-type &rest args))
+  (let ((names (loop 
+		for arg in args 
+		collect (if (atom arg) (gensym) (first arg))))
+	(types (loop 
+		for arg in args 
+		collect (if (atom arg) arg (second arg)))))
+    `(defcallback ,name (,return-type ,@(mapcar #'list names types)
+			 (callback-id unsigned-int))
+      (invoke-callback callback-id ',return-type ,@names))))
+
+(defmacro with-callback-function ((id function) &body body)
+  `(let ((,id (register-callback-function ,function)))
+    (unwind-protect
+	 (progn ,@body)
+      (destroy-user-data ,id))))
+
+