Introspected classes now defined in propper order

[clg] / glib / gobject.lisp

diff --git a/glib/gobject.lisp b/glib/gobject.lisp
index dc6bd78a1b09ed22b95f0266b2a442df509d86c9..a722174e7f2fdb639eb7dfd1c700b08f3a1d3bf3 100644 (file)
--- a/glib/gobject.lisp
+++ b/glib/gobject.lisp
@@ -15,139 +15,54 @@
 ;; License along with this library; if not, write to the Free Software
 ;; Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
 ;; 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: gobject.lisp,v 1.13 2004-10-27 14:58:59 espen Exp $
+;; $Id: gobject.lisp,v 1.30 2005-02-01 15:24:52 espen Exp $

 
 (in-package "GLIB")
 
 
 
 (in-package "GLIB")
 
 

-(eval-when (:compile-toplevel :load-toplevel :execute)
-  (defclass gobject (ginstance)
-    ()
-    (:metaclass ginstance-class)
-    (:alien-name "GObject")
-    (:copy %object-ref)
-    (:free %object-unref)))
+;;;; Metaclass used for subclasses of gobject

 
 

+(eval-when (:compile-toplevel :load-toplevel :execute)
+  (defclass gobject-class (ginstance-class)
+    ())

 
 

-(defmethod initialize-instance ((object gobject) &rest initargs)
-  (let ((slotds (class-slots (class-of object)))
-       (names (make-array 0 :adjustable t :fill-pointer t))
-       (values (make-array 0 :adjustable t :fill-pointer t)))
-
-    (loop 
-     as tmp = initargs then (cddr tmp) while tmp
-     as key = (first tmp)
-     as value = (second tmp)
-     as slotd = (find-if
-                #'(lambda (slotd)
-                    (member key (slot-definition-initargs slotd)))
-                slotds)
-     when (and (typep slotd 'effective-gobject-slot-definition)
-              (slot-value slotd 'construct))
-     do (let ((type (find-type-number (slot-definition-type slotd))))
-         (vector-push-extend (slot-definition-pname slotd) names)
-         (vector-push-extend (gvalue-new type value) values)
-         (remf initargs key)))
-
-    (setf  
-     (slot-value object 'location) 
-     (if (zerop (length names))
-        (%gobject-new (type-number-of object))
-       (%gobject-newvv (type-number-of object) (length names) names values))))
-  (apply #'call-next-method object initargs))
+  (defmethod validate-superclass ((class gobject-class)
+                               (super pcl::standard-class))
+;  (subtypep (class-name super) 'gobject)
+    t))

 
 

+(defclass direct-property-slot-definition (direct-virtual-slot-definition)
+  ((pname :reader slot-definition-pname :initarg :pname)
+   (readable :initform t :reader slot-readable-p :initarg :readable)
+   (writable :initform t :reader slot-writable-p :initarg :writable)
+   (construct :initform nil :initarg :construct)))

 
 

+(defclass effective-property-slot-definition (effective-virtual-slot-definition)
+  ((pname :reader slot-definition-pname :initarg :pname)
+   (readable :reader slot-readable-p :initarg :readable)
+   (writable :reader slot-writable-p :initarg :writable)
+   (construct :initarg :construct)))

 
 

-(defbinding (%gobject-new "g_object_new") () pointer
-  (type type-number)
-  (nil null))
+(defclass direct-user-data-slot-definition (direct-virtual-slot-definition)
+  ())

 
 

-(defbinding (%gobject-newvv "g_object_newvv") () pointer
-  (type type-number)
-  (n-parameters unsigned-int)
-  (names (vector string))
-  (values (vector gvalue)))
+(defclass effective-user-data-slot-definition (effective-virtual-slot-definition)
+  ())

 
 
 
 

-(defbinding %object-ref (type location) pointer
+(defbinding %object-ref () pointer

   (location pointer))
 
   (location pointer))
 

- (defbinding %object-unref (type location) nil
-   (location pointer))
-
-(defun object-ref (object)
-  (%object-ref nil (proxy-location object)))
-
-(defun object-unref (object)
-  (%object-unref nil (proxy-location object)))
-
-
-
-;;;; Property stuff
-
-(defbinding %object-set-property () nil
-  (object gobject)
-  (name string)
-  (value gvalue))
-
-(defbinding %object-get-property () nil
-  (object gobject)
-  (name string)
-  (value gvalue))
-
-(defbinding %object-notify () nil
-  (object gobject)
-  (name string))
-
-(defbinding object-freeze-notify () nil
-  (object gobject))
-
-(defbinding object-thaw-notify () nil
-  (object gobject))
-
-(defbinding %object-set-qdata-full () nil
-  (object gobject)
-  (id quark)
-  (data unsigned-long)
-  (destroy-marshal pointer))
-
-
-;;;; User data
-
-(defun (setf object-data) (data object key &key (test #'eq))
-  (%object-set-qdata-full
-   object (quark-from-object key :test test)
-   (register-user-data data) *destroy-notify*)
-  data)
-
-(defbinding %object-get-qdata () unsigned-long
-  (object gobject)              
-  (id quark))
-
-(defun object-data (object key &key (test #'eq))
-  (find-user-data
-   (%object-get-qdata object (quark-from-object key :test test))))
-
-
-
-;;;; Metaclass used for subclasses of gobject
-
-(eval-when (:compile-toplevel :load-toplevel :execute)
-  (defclass gobject-class (ginstance-class)
-    ())
-
-  (defclass direct-gobject-slot-definition (direct-virtual-slot-definition)
-    ((pname :reader slot-definition-pname :initarg :pname)
-     (readable :initform t :reader slot-readable-p :initarg :readable)
-     (writable :initform t :reader slot-writable-p :initarg :writable)
-     (construct :initform nil :initarg :construct)))
+(defbinding %object-unref () nil
+  (location pointer))

 
 

-  (defclass effective-gobject-slot-definition (effective-virtual-slot-definition)
-    ((pname :reader slot-definition-pname :initarg :pname)
-     (readable :reader slot-readable-p :initarg :readable)
-     (writable :reader slot-writable-p :initarg :writable)
-     (construct :initarg :construct))))
+(defmethod reference-foreign ((class gobject-class) location)
+  (declare (ignore class))
+  (%object-ref location))

 
 

+(defmethod unreference-foreign ((class gobject-class) location)
+  (declare (ignore class))
+  (%object-unref location))

 
 
 ; (defbinding object-class-install-param () nil
 
 
 ; (defbinding object-class-install-param () nil


@@ -165,16 +80,18 @@ (defun signal-name-to-string (name)
 
 (defmethod direct-slot-definition-class ((class gobject-class) &rest initargs)
   (case (getf initargs :allocation)
 
 (defmethod direct-slot-definition-class ((class gobject-class) &rest initargs)
   (case (getf initargs :allocation)

-    (:property (find-class 'direct-gobject-slot-definition))
+    (:property (find-class 'direct-property-slot-definition))
+    (:user-data (find-class 'direct-user-data-slot-definition))

     (t (call-next-method))))
 
 (defmethod effective-slot-definition-class ((class gobject-class) &rest initargs)
   (case (getf initargs :allocation)
     (t (call-next-method))))
 
 (defmethod effective-slot-definition-class ((class gobject-class) &rest initargs)
   (case (getf initargs :allocation)

-    (:property (find-class 'effective-gobject-slot-definition))
+    (:property (find-class 'effective-property-slot-definition))
+    (:user-data (find-class 'effective-user-data-slot-definition))

     (t (call-next-method))))
 
 (defmethod compute-effective-slot-definition-initargs ((class gobject-class) direct-slotds)
     (t (call-next-method))))
 
 (defmethod compute-effective-slot-definition-initargs ((class gobject-class) direct-slotds)

-  (if (eq (most-specific-slot-value direct-slotds 'allocation) :property)
+  (if (typep (first direct-slotds) 'direct-property-slot-definition)

       (nconc 
        (list :pname (signal-name-to-string 
                     (most-specific-slot-value direct-slotds 'pname))
       (nconc 
        (list :pname (signal-name-to-string 
                     (most-specific-slot-value direct-slotds 'pname))


@@ -185,58 +102,212 @@ (defmethod compute-effective-slot-definition-initargs ((class gobject-class) dir
     (call-next-method)))
 
 
     (call-next-method)))
 
 

-(defmethod initialize-internal-slot-functions ((slotd effective-gobject-slot-definition))
+(defmethod initialize-internal-slot-functions ((slotd effective-property-slot-definition))

   (let* ((type (slot-definition-type slotd))
         (pname (slot-definition-pname slotd))
         (type-number (find-type-number type)))
   (let* ((type (slot-definition-type slotd))
         (pname (slot-definition-pname slotd))
         (type-number (find-type-number type)))

-    (unless (slot-boundp slotd 'reader-function)
+    (when (and (not (slot-boundp slotd 'getter)) (slot-readable-p slotd))

       (setf 
       (setf 

-       (slot-value slotd 'reader-function)
-       (if (slot-readable-p slotd)
-          #'(lambda (object)
-              (with-gc-disabled
-                  (let ((gvalue (gvalue-new type-number)))
-                    (%object-get-property object pname gvalue)
-                    (unwind-protect
-                         (funcall
-                          (intern-reader-function (type-from-number type-number)) gvalue +gvalue-value-offset+) ; temporary workaround for wrong topological sorting of types
-                      (gvalue-free gvalue t)))))
-          #'(lambda (value object)
-              (error "Slot is not readable: ~A" (slot-definition-name slotd))))))
+       (slot-value slotd 'getter)
+       (let ((reader nil))
+        #'(lambda (object)
+            (unless reader
+              (setq reader (reader-function type))) ;(type-from-number type-number))))
+            (let ((gvalue (gvalue-new type-number)))
+              (%object-get-property object pname gvalue)
+              (unwind-protect
+                (funcall reader  gvalue +gvalue-value-offset+)
+                (gvalue-free gvalue t)))))))

     
     

-    (unless (slot-boundp slotd 'writer-function)
+    (when (and (not (slot-boundp slotd 'setter)) (slot-writable-p slotd))

       (setf 
       (setf 

-       (slot-value slotd 'writer-function)
-       (if (slot-writable-p slotd)
-          #'(lambda (value object)
-              (with-gc-disabled
-                  (let ((gvalue (gvalue-new type-number)))
-                    (funcall
-                     (intern-writer-function (type-from-number type-number)) ; temporary
-                     value gvalue +gvalue-value-offset+)
-                    (%object-set-property object pname gvalue)
-                    (funcall
-                     (intern-destroy-function (type-from-number type-number)) ; temporary
-                     gvalue +gvalue-value-offset+)
-                    (gvalue-free gvalue nil)
-                    value)))
-          #'(lambda (value object)
-              (error "Slot is not writable: ~A" (slot-definition-name slotd))))))
-    
-    (unless (slot-boundp slotd 'boundp-function)
+       (slot-value slotd 'setter)
+       (let ((writer nil))
+        #'(lambda (value object)
+            (unless writer
+              (setq writer (writer-function type))) ;(type-from-number type-number))))
+            (let ((gvalue (gvalue-new type-number)))
+              (funcall writer value gvalue +gvalue-value-offset+)
+              (%object-set-property object pname gvalue)
+              (gvalue-free gvalue t)
+              value))))))
+
+  (call-next-method))
+
+(defmethod initialize-internal-slot-functions ((slotd effective-user-data-slot-definition))
+  (let ((slot-name (slot-definition-name slotd)))
+    (unless (slot-boundp slotd 'getter)
+      (setf 
+       (slot-value slotd 'getter)
+       #'(lambda (object)
+          (prog1 (user-data object slot-name)))))
+    (unless (slot-boundp slotd 'setter)
+      (setf 
+       (slot-value slotd 'setter)
+       #'(lambda (value object)
+          (setf (user-data object slot-name) value))))
+    (unless (slot-boundp slotd 'boundp)

       (setf 
       (setf 

-       (slot-value slotd 'boundp-function)
+       (slot-value slotd 'boundp)

        #'(lambda (object)
        #'(lambda (object)

-          (declare (ignore object))
-          t))))
+          (user-data-p object slot-name)))))

   (call-next-method))
 
 
   (call-next-method))
 
 

-(defmethod validate-superclass ((class gobject-class)
-                               (super pcl::standard-class))
-;  (subtypep (class-name super) 'gobject)
-  t)
+;;;; Super class for all classes in the GObject type hierarchy
+
+(eval-when (:compile-toplevel :load-toplevel :execute)
+  (defclass gobject (ginstance)
+    ()
+    (:metaclass gobject-class)
+    (:alien-name "GObject")))
+
+
+(defun initial-add (object function initargs key pkey)
+  (loop 
+   as (initarg value . rest) = initargs then rest
+   do (cond
+       ((eq initarg key) (funcall function object value))
+       ((eq initarg pkey) (mapc #'(lambda (value)
+                                   (funcall function object value))
+                               value)))
+       while rest))
+
+(defun initial-apply-add (object function initargs key pkey)
+  (initial-add object #'(lambda (object value)
+                         (apply function object (mklist value)))
+              initargs key pkey))
+
+
+(defmethod initialize-instance ((object gobject) &rest initargs)
+  (unless (slot-boundp object 'location)
+    ;; Extract initargs which we should pass directly to the GObeject
+    ;; constructor
+    (let* ((slotds (class-slots (class-of object)))
+          (args (when initargs
+                  (loop 
+                   as (key value . rest) = initargs then rest
+                   as slotd = (find-if
+                               #'(lambda (slotd)
+                                   (member key (slot-definition-initargs slotd)))
+                               slotds)
+                   when (and (typep slotd 'effective-property-slot-definition)
+                             (slot-value slotd 'construct))
+                   collect (progn 
+                             (remf initargs key)
+                             (list 
+                              (slot-definition-pname slotd)
+                              (slot-definition-type slotd)
+                              value))
+                   while rest))))
+      (if args
+         (let* ((string-size (size-of 'string))
+                (string-writer (writer-function 'string))
+                (string-destroy (destroy-function 'string))
+                (params (allocate-memory 
+                         (* (length args) (+ string-size +gvalue-size+)))))
+           (loop
+            for (pname type value) in args
+            as tmp = params then (sap+ tmp (+ string-size +gvalue-size+))
+            do (funcall string-writer pname tmp)
+            (gvalue-init (sap+ tmp string-size) type value))
+           (unwind-protect
+               (setf  
+                (slot-value object 'location) 
+                (%gobject-newv (type-number-of object) (length args) params))
+             (loop
+              repeat (length args)
+              as tmp = params then (sap+ tmp (+ string-size +gvalue-size+))
+              do (funcall string-destroy tmp)
+              (gvalue-unset (sap+ tmp string-size)))
+             (deallocate-memory params)))
+       (setf  
+        (slot-value object 'location) 
+        (%gobject-new (type-number-of object))))))
+
+  (apply #'call-next-method object initargs))
+
+
+(defmethod instance-finalizer ((instance gobject))
+  (let ((location (proxy-location instance)))
+    #'(lambda ()
+       (remove-cached-instance location)
+       (%object-unref location))))
+
+
+(defbinding (%gobject-new "g_object_new") () pointer
+  (type type-number)
+  (nil null))
+
+(defbinding (%gobject-newv "g_object_newv") () pointer
+  (type type-number)
+  (n-parameters unsigned-int)
+  (params pointer))
+
+
+
+;;;; Property stuff
+
+(defbinding %object-set-property () nil
+  (object gobject)
+  (name string)
+  (value gvalue))
+
+(defbinding %object-get-property () nil
+  (object gobject)
+  (name string)
+  (value gvalue))

 
 

+(defbinding %object-notify () nil
+  (object gobject)
+  (name string))
+
+(defbinding object-freeze-notify () nil
+  (object gobject))
+
+(defbinding object-thaw-notify () nil
+  (object gobject))
+
+
+;;;; User data
+
+(defbinding %object-set-qdata-full () nil
+  (object gobject)
+  (id quark)
+  (data unsigned-long)
+  (destroy-marshal pointer))
+
+(defun (setf user-data) (data object key)
+  (%object-set-qdata-full object (quark-intern key)
+   (register-user-data data) (callback %destroy-user-data))
+  data)
+
+;; deprecated
+(defun (setf object-data) (data object key &key (test #'eq))
+  (assert (eq test #'eq))
+  (setf (user-data object key) data))
+
+(defbinding %object-get-qdata () unsigned-long
+  (object gobject)              
+  (id quark))
+
+(defun user-data (object key)
+  (find-user-data (%object-get-qdata object (quark-intern key))))
+
+;; deprecated
+(defun object-data (object key &key (test #'eq))
+  (assert (eq test #'eq))
+  (user-data object key))
+
+(defun user-data-p (object key)
+  (user-data-exists-p (%object-get-qdata object (quark-intern key))))
+
+(defbinding %object-steal-qdata () unsigned-long
+  (object gobject)              
+  (id quark))
+
+(defun unset-user-data (object key)
+  (destroy-user-data (%object-steal-qdata object (quark-intern key))))

 
 
 ;;;;
 
 
 ;;;;


@@ -245,21 +316,29 @@ (defbinding %object-class-list-properties () pointer
   (class pointer)
   (n-properties unsigned-int :out))
 
   (class pointer)
   (n-properties unsigned-int :out))
 

-(defun query-object-class-properties (type-number &optional
-                                     inherited-properties)
-  (let ((class (type-class-ref type-number)))
-    (multiple-value-bind (array length)
-       (%object-class-list-properties class)
-      (unwind-protect
-         (let ((all-properties
-                (map-c-array 'list #'identity array 'param length)))
-           (if (not inherited-properties)
-               (delete-if
-                #'(lambda (param)
-                    (not (eql type-number (param-owner-type param))))
-                all-properties)
-             all-properties))
-       (deallocate-memory array)))))
+
+(defun %map-params (params length type inherited-p)
+  (if inherited-p
+      (map-c-vector 'list #'identity params 'param length)
+    (let ((properties ()))
+      (map-c-vector 'list 
+       #'(lambda (param)
+          (when (eql (param-owner-type param) type)
+            (push param properties)))
+       params 'param length)
+      (nreverse properties))))
+
+(defun query-object-class-properties (type &optional inherited-p)
+  (let* ((type-number (find-type-number type))
+        (class (type-class-ref type-number)))
+    (unwind-protect
+        (multiple-value-bind (array length)
+            (%object-class-list-properties class)
+          (unwind-protect
+               (%map-params array length type-number inherited-p)
+            (deallocate-memory array)))
+;      (type-class-unref type-number)
+      )))

 
 
 (defun default-slot-name (name)
 
 
 (defun default-slot-name (name)


@@ -271,78 +350,104 @@ (defun default-slot-accessor (class-name slot-name type)
     nil "~A-~A~A" class-name slot-name
     (if (eq type 'boolean) "-P" ""))))
 
     nil "~A-~A~A" class-name slot-name
     (if (eq type 'boolean) "-P" ""))))
 

-(defun expand-gobject-type (type-number &optional options
-                           (metaclass 'gobject-class))
-  (let* ((supers (cons (supertype type-number) (implements type-number)))
-        (class  (type-from-number type-number))
-        (manual-slots (getf options :slots))
-        (expanded-slots
-         (mapcar
-          #'(lambda (param)
-              (with-slots (name flags value-type documentation) param
-                (let* ((slot-name (default-slot-name name))
-;                      (slot-type value-type) ;(type-from-number value-type t))
-                       (slot-type (or (type-from-number value-type) value-type))
-                       (accessor
-                        (default-slot-accessor class slot-name slot-type)));(type-from-number slot-type)))) ; temporary workaround for wrong topological sorting of types
-
-                  `(,slot-name
-                    :allocation :property
-                    :pname ,name
-                    ,@(cond
-                       ((and
-                         (member :writable flags)
-                         (member :readable flags)
-                         (not (member :construct-only flags)))
-                        (list :accessor accessor))
-                       ((and (member :writable flags)
-                             (not (member :construct-only flags)))
-                        (list :writer `(setf ,accessor)))
-                       ((member :readable flags)
-                        (list :reader accessor)))
-                    ,@(when (or
-                             (not (member :writable flags))
-                             (member :construct-only flags))
-                        (list :writable nil))
-                    ,@(when (not (member :readable flags))
-                        (list :readable nil))
-                    ,@(when (or 
-                             (member :construct flags)
-                             (member :construct-only flags))
-                        (list :construct t))
-                    ,@(when (or
-                             (member :construct flags)
-                             (member :construct-only flags)
-                             (member :writable flags))
-                        (list :initarg (intern (string slot-name) "KEYWORD")))
-                    :type ,slot-type
-                    ,@(when documentation
-                        (list :documentation documentation))))))
-          (query-object-class-properties type-number))))
-
-    (dolist (slot-def (reverse manual-slots))
-      (let ((name (car slot-def))
-           (pname (getf (cdr slot-def) :pname)))
-       (setq
-        expanded-slots
-        (delete-if
-         #'(lambda (expanded-slot-def)
-             (or
-              (eq name (car expanded-slot-def))
-              (and
-               pname
-               (string= pname (getf (cdr expanded-slot-def) :pname)))))
-         expanded-slots))
-
-       (unless (getf (cdr slot-def) :ignore)
-         (push slot-def expanded-slots))))
-    
-    `(progn
-       (defclass ,class ,supers
-        ,expanded-slots
-        (:metaclass ,metaclass)
-        (:alien-name ,(find-type-name type-number))))))
-
-
-(register-derivable-type 'gobject "GObject" 'expand-gobject-type)

 
 

+(defun slot-definition-from-property (class property &optional slot-name args)
+  (with-slots (name flags value-type documentation) property
+    (let* ((slot-name (or slot-name (default-slot-name name)))
+          (slot-type (or (getf args :type) (type-from-number value-type) 'pointer))
+          (accessor (default-slot-accessor class slot-name slot-type)))
+      
+      `(,slot-name
+       :allocation :property :pname ,name
+
+       ,@(cond
+          ((find :unbound args) (list :unbound (getf args :unbound))))
+       
+       ;; accessors
+       ,@(cond
+          ((and
+            (member :writable flags) (member :readable flags)
+            (not (member :construct-only flags)))
+           (list :accessor accessor))
+          ((and (member :writable flags) (not (member :construct-only flags)))
+           (list :writer `(setf ,accessor)))
+          ((member :readable flags)
+           (list :reader accessor)))
+
+       ;; readable/writable/construct
+       ,@(when (or (not (member :writable flags))
+                   (member :construct-only flags))
+           '(:writable nil))
+       ,@(when (not (member :readable flags))
+           '(:readable nil))
+       ,@(when (or (member :construct flags) 
+                   (member :construct-only flags))
+           '(:construct t))
+       
+       ;; initargs
+       ,@(when (or (member :construct flags)
+                   (member :construct-only flags)
+                   (member :writable flags))
+           (list :initarg (intern (string slot-name) "KEYWORD")))
+       ,@(cond
+          ((find :initarg args) (list :initarg (getf args :initarg))))
+       
+       :type ,slot-type
+       :documentation ,documentation))))
+
+
+(defun slot-definitions (class properties slots)
+  (loop 
+   for property in properties
+   as slot = (or
+             (find (param-name property) slots 
+              :key #'(lambda (slot) (getf (rest slot) :pname)) 
+              :test #'string=)
+             (find (param-name property) slots 
+              :key #'first :test #'string-equal))
+   do (cond
+       ((not slot) 
+       (push (slot-definition-from-property class property) slots))
+       ((getf (rest slot) :merge)
+       (setf 
+        (rest slot) 
+        (rest (slot-definition-from-property class property (first slot) (rest slot)))))))
+  (delete-if #'(lambda (slot) (getf (rest slot) :ignore)) slots))
+
+
+(defun expand-gobject-type (type forward-p options &optional (metaclass 'gobject-class))
+  (let ((supers (cons (supertype type) (implements type)))
+       (class  (type-from-number type))
+       (slots (getf options :slots)))    
+    `(defclass ,class ,supers
+       ,(unless forward-p
+         (slot-definitions class (query-object-class-properties type) slots))
+      (:metaclass ,metaclass)
+      (:alien-name ,(find-type-name type)))))
+
+(defun gobject-dependencies (type)
+  (delete-duplicates (mapcar #'param-value-type (query-object-class-properties type))))
+
+
+(register-derivable-type 'gobject "GObject" 'expand-gobject-type 'gobject-dependencies)
+
+
+;;; Pseudo type for gobject instances which have their reference count
+;;; increased by the returning function
+
+(defmethod alien-type ((type (eql 'referenced)) &rest args)
+  (declare (ignore type args))
+  (alien-type 'gobject))
+
+(defmethod from-alien-form (form (type (eql 'referenced)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (type) args
+    (if (subtypep type 'gobject)
+       (let ((instance (make-symbol "INSTANCE")))
+         `(let ((,instance ,(from-alien-form form type)))
+            (when ,instance
+              (%object-unref (proxy-location ,instance)))
+            ,instance))
+      (error "~A is not a subclass of GOBJECT" type))))
+
+(export 'referenced)