Added DEFINE-SIGNAL-HANDLER to define class signal handlers

diff --git a/glib/gcallback.lisp b/glib/gcallback.lisp
index 4a487775e35c3c225ee9f5202b06377ac1b7250d..e8d7ca48fddfd5d935c3cbd8ae6a542eb9b8f05f 100644 (file)
--- a/glib/gcallback.lisp
+++ b/glib/gcallback.lisp
@@ -20,7 +20,7 @@
 ;; TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 ;; SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-;; $Id: gcallback.lisp,v 1.25 2005-04-24 13:25:31 espen Exp $
+;; $Id: gcallback.lisp,v 1.26 2006-02-01 14:18:49 espen Exp $
 
 (in-package "GLIB")
 
@@ -186,6 +186,79 @@ (defun describe-signal (signal-id &optional type)
 
 ;;;; Signal connecting and controlling
 
+(defvar *overridden-signals* (make-hash-table :test 'equalp))
+
+(defbinding %signal-override-class-closure () nil
+  (signal-id unsigned-int)
+  (type-number type-number)
+  (callback-closure pointer))
+
+
+(defun signal-override-class-closure (name type function)
+  (let* ((signal-id (ensure-signal-id-from-type name type))
+        (type-number (find-type-number type t))
+        (callback-id (gethash (cons type-number signal-id) *overridden-signals*)))
+    (if callback-id
+       (update-user-data callback-id function)
+      (multiple-value-bind (callback-closure callback-id)
+         (make-callback-closure function)
+       (%signal-override-class-closure signal-id type-number callback-closure)
+       (setf 
+        (gethash (cons type-number signal-id) *overridden-signals*)
+        callback-id)))))
+
+
+(defbinding %signal-chain-from-overridden () nil
+  (args pointer)
+  (return-value (or null gvalue)))
+
+
+(defun %call-next-handler (n-params types args defaults return-type)
+  (let ((params (allocate-memory (* n-params +gvalue-size+))))
+    (loop 
+     as tmp = args then (rest tmp)
+     for default in defaults
+     for type in types
+     for offset from 0 by +gvalue-size+
+     as arg = (if tmp (car tmp) default)
+     do (gvalue-init (sap+ params offset) type arg))
+
+    (unwind-protect
+       (if return-type
+           (with-gvalue (return-value return-type)
+             (%signal-chain-from-overridden params return-value))
+         (%signal-chain-from-overridden params nil))
+      (progn
+       (loop
+        repeat n-params
+        for offset from 0 by +gvalue-size+
+        do (gvalue-unset (sap+ params offset)))
+       (deallocate-memory params)))))
+
+
+(defmacro define-signal-handler (name ((object class) &rest args) &body body)
+  (let* ((info (signal-query (ensure-signal-id-from-type name class)))
+        (types (cons class (signal-param-types info)))
+        (n-params (1+ (slot-value info 'n-params)))
+        (return-type (type-from-number (slot-value info 'return-type)))
+        (vars (loop
+               for arg in args
+               until (eq arg '&rest)
+               collect arg))
+        (rest (cadr (member '&rest args)))
+        (next (make-symbol "ARGS")))
+
+    `(progn
+       (signal-override-class-closure ',name ',class 
+       #'(lambda (,object ,@args)
+           (flet ((call-next-handler (&rest ,next)
+                    (let ((defaults (list* ,object ,@vars ,rest)))
+                      (%call-next-handler 
+                       ,n-params ',types ,next defaults ',return-type))))
+             ,@body)))
+       ',name)))
+
+
 (defbinding %signal-stop-emission () nil
   (instance ginstance)
   (signal-id unsigned-int)