X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/clg/blobdiff_plain/9adccb27da69b60d058aa37867d55ea20ecf97ca..4a64c16d900f59a4e6b1ac57fc8658f6faabbcfc:/glib/proxy.lisp

diff --git a/glib/proxy.lisp b/glib/proxy.lisp
index eeecae1..ff08b84 100644
--- a/glib/proxy.lisp
+++ b/glib/proxy.lisp
@@ -1,21 +1,26 @@
-;; Common Lisp bindings for GTK+ v2.0
-;; Copyright (C) 2000 Espen S. Johnsen <esj@stud.cs.uit.no>
+;; Common Lisp bindings for GTK+ v2.x
+;; Copyright 2000-2005 Espen S. Johnsen <espen@users.sf.net>
 ;;
-;; This library is free software; you can redistribute it and/or
-;; modify it under the terms of the GNU Lesser General Public
-;; License as published by the Free Software Foundation; either
-;; version 2 of the License, or (at your option) any later version.
+;; Permission is hereby granted, free of charge, to any person obtaining
+;; a copy of this software and associated documentation files (the
+;; "Software"), to deal in the Software without restriction, including
+;; without limitation the rights to use, copy, modify, merge, publish,
+;; distribute, sublicense, and/or sell copies of the Software, and to
+;; permit persons to whom the Software is furnished to do so, subject to
+;; the following conditions:
 ;;
-;; This library is distributed in the hope that it will be useful,
-;; but WITHOUT ANY WARRANTY; without even the implied warranty of
-;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-;; Lesser General Public License for more details.
+;; The above copyright notice and this permission notice shall be
+;; included in all copies or substantial portions of the Software.
 ;;
-;; You should have received a copy of the GNU Lesser General Public
-;; License along with this library; if not, write to the Free Software
-;; Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+;; EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+;; MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+;; IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+;; CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+;; TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+;; SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-;; $Id: proxy.lisp,v 1.11 2004-11-06 21:39:58 espen Exp $
+;; $Id: proxy.lisp,v 1.26 2006-02-06 11:52:24 espen Exp $
 
 (in-package "GLIB")
 
@@ -28,102 +33,179 @@   (defclass virtual-slots-class (standard-class)
   (defclass direct-virtual-slot-definition (standard-direct-slot-definition)
     ((setter :reader slot-definition-setter :initarg :setter)
      (getter :reader slot-definition-getter :initarg :getter)
+     (unbound :reader slot-definition-unbound :initarg :unbound)
      (boundp :reader slot-definition-boundp :initarg :boundp)))
   
   (defclass effective-virtual-slot-definition (standard-effective-slot-definition)
     ((setter :reader slot-definition-setter :initarg :setter)
      (getter :reader slot-definition-getter :initarg :getter)
+     (unbound :reader slot-definition-unbound :initarg :unbound)
      (boundp :reader slot-definition-boundp :initarg :boundp)))
 
-  (defun most-specific-slot-value (instances slot &optional default)
-    (let ((object (find-if
-		   #'(lambda (ob)
-		       (and (slot-exists-p ob slot) (slot-boundp ob slot)))
-		   instances)))
-      (if object
-	  (slot-value object slot)
-	  default))))
-
+  (defclass direct-special-slot-definition (standard-direct-slot-definition)
+    ())
   
+  (defclass effective-special-slot-definition (standard-effective-slot-definition)
+    ()))
+
+(defvar *unbound-marker* (gensym "UNBOUND-MARKER-"))
+
+(defun most-specific-slot-value (instances slot &optional (default *unbound-marker*))
+  (let ((object (find-if
+		 #'(lambda (ob)
+		     (and (slot-exists-p ob slot) (slot-boundp ob slot)))
+		 instances)))
+    (if object
+	(slot-value object slot)
+      default)))
+
+(defmethod initialize-instance ((slotd effective-special-slot-definition) &rest initargs)
+  (declare (ignore initargs))
+  (call-next-method)
+  (setf (slot-value slotd 'allocation) :instance))
+
 
 (defmethod direct-slot-definition-class ((class virtual-slots-class) &rest initargs)
-  (if (eq (getf initargs :allocation) :virtual)
-      (find-class 'direct-virtual-slot-definition)
-    (call-next-method)))
+  (case (getf initargs :allocation)
+    (:virtual (find-class 'direct-virtual-slot-definition))
+    (:special (find-class 'direct-special-slot-definition))
+    (t (call-next-method))))
 
 (defmethod effective-slot-definition-class ((class virtual-slots-class) &rest initargs)
-  (if (eq (getf initargs :allocation) :virtual)
-      (find-class 'effective-virtual-slot-definition)
-    (call-next-method)))
+  (case (getf initargs :allocation)
+    (:virtual (find-class 'effective-virtual-slot-definition))
+    (:special (find-class 'effective-special-slot-definition))
+    (t (call-next-method))))
 
 
 (defmethod initialize-internal-slot-functions ((slotd effective-virtual-slot-definition))
-  (with-slots (getter setter boundp) slotd
-    (unless (slot-boundp slotd 'reader-function)
-      (setf 
+  (if (not (slot-boundp slotd 'getter))
+      (setf
        (slot-value slotd 'reader-function)
-       (etypecase getter
-	 (function getter)
-	 (null #'(lambda (object)
-		   (declare (ignore object))
-		   (error "Can't read slot: ~A" (slot-definition-name slotd))))
-	 (symbol #'(lambda (object)
-		     (funcall getter object)))
-	 (string ;(let ()(reader  (mkbinding getter 
-;; 				(slot-definition-type slotd) 'pointer)))
-		   (setf (slot-value slotd 'reader-function)
-			 #'(lambda (object)
-			     (let ((reader
-				(mkbinding getter 
-				 (slot-definition-type slotd) 'pointer)))
-			     (funcall reader (proxy-location object)))))))))
-
-    (unless (slot-boundp slotd 'writer-function)
+       #'(lambda (object)
+	   (declare (ignore object))
+	   (error "Can't read slot: ~A" (slot-definition-name slotd)))
+       (slot-value slotd 'boundp-function)
+       #'(lambda (object) (declare (ignore object)) nil))
+
+    (let ((getter-function
+	   (let ((getter (slot-value slotd 'getter)))
+	     (etypecase getter
+	       (function getter)
+	       (symbol 
+		#'(lambda (object)
+		    (funcall getter object)))
+	       (string 
+		(let ((reader nil))
+		  (setf (slot-value slotd 'reader-function)
+			#'(lambda (object)
+			    (unless reader
+			      (setq reader
+			       (mkbinding getter 
+				(slot-definition-type slotd) 'pointer)))
+			    (funcall reader (foreign-location object))))))))))
+
       (setf 
-       (slot-value slotd 'writer-function)
+       (slot-value slotd 'boundp-function)
+       (cond
+	((slot-boundp slotd 'unbound)
+	 (let ((unbound-value (slot-value slotd 'unbound)))
+	   #'(lambda (object)
+	       (not (eq (funcall getter-function object) unbound-value)))))
+	((slot-boundp slotd 'boundp)
+	 (let ((boundp (slot-value slotd 'boundp)))
+	   (etypecase boundp
+	     (function boundp)
+	     (symbol #'(lambda (object)
+			 (funcall boundp object)))
+	     (string (let ((reader ()))
+		       #'(lambda (object)
+			   (unless reader
+			     (setq reader
+			      (mkbinding boundp
+			       (slot-definition-type slotd) 'pointer)))
+			   (funcall reader (foreign-location object))))))))
+	((multiple-value-bind (unbound-p unbound-value)
+	     (unbound-value (slot-definition-type slotd))
+	   (when unbound-p
+	     #'(lambda (object)
+		 (not (eq (funcall getter-function object) unbound-value))))))
+	(#'(lambda (object) (declare (ignore object)) t))))
+
+      (setf
+       (slot-value slotd 'reader-function)
+       (cond
+	((slot-boundp slotd 'unbound)
+	 (let ((unbound (slot-value slotd 'unbound))
+	       (slot-name (slot-definition-name slotd)))
+	   #'(lambda (object)
+	       (let ((value (funcall getter-function object)))
+		 (if (eq value unbound)
+		     (slot-unbound (class-of object) object slot-name)
+		   value)))))
+	((slot-boundp slotd 'boundp)
+	 (let ((boundp-function (slot-value slotd 'boundp-function)))
+	   #'(lambda (object)
+	       (and
+		(funcall boundp-function object)
+		(funcall getter-function object)))))
+	((multiple-value-bind (unbound-p unbound-value)
+	     (unbound-value (slot-definition-type slotd))
+	   (let ((slot-name (slot-definition-name slotd)))
+	     (when unbound-p
+	       #'(lambda (object)
+		   (let ((value (funcall getter-function object)))
+		     (if (eq value unbound-value)
+			 (slot-unbound (class-of object) object slot-name)
+			 value)))))))
+	(getter-function)))))
+
+  (setf 
+   (slot-value slotd 'writer-function)
+   (if (not (slot-boundp slotd 'setter))
+       #'(lambda (object)
+	   (declare (ignore object))
+	   (error "Can't set slot: ~A" (slot-definition-name slotd)))
+     (with-slots (setter) slotd
        (etypecase setter
 	 (function setter)
-	 (null #'(lambda (object)
-		   (declare (ignore object))
-		   (error "Can't set slot: ~A" (slot-definition-name slotd))))
-	 ((or symbol cons) #'(lambda (value object)
-			       (funcall (fdefinition setter) value object)))
+	 ((or symbol cons) 
+	  #'(lambda (value object)
+	      (funcall (fdefinition setter) value object)))
 	 (string
-	  (let ((writer ()));; (mkbinding setter 'nil 'pointer 
-;; 			 (slot-definition-type slotd))))
-	    (setf (slot-value slotd 'writer-function)
-		  #'(lambda (value object)
-		      (unless writer
-			(setq writer
-			 (mkbinding setter 'nil 'pointer 
- 			  (slot-definition-type slotd))))
-		      (funcall writer (proxy-location object) value))))))))
-
-    (unless (slot-boundp slotd 'boundp-function)
-      (setf 
-       (slot-value slotd 'boundp-function)
-       (etypecase boundp
-	 (function boundp)
-	 (null #'(lambda (object)
-		   (declare (ignore object))
-		   t))
-	 (symbol #'(lambda (object)
-		     (funcall boundp object)))))))
+	  (let ((writer ()))
+	    (setf
+	     (slot-value slotd 'writer-function)
+	     #'(lambda (value object)
+		 (unless writer
+		   (setq writer
+		    (mkbinding setter 'nil 'pointer 
+		     (slot-definition-type slotd))))
+		 (funcall writer (foreign-location object) value)))))))))
+
   (initialize-internal-slot-gfs (slot-definition-name slotd)))
 
 
 
-(defmethod compute-slot-accessor-info ((slotd effective-virtual-slot-definition)
-					    type gf)
+(defmethod compute-slot-accessor-info ((slotd effective-virtual-slot-definition) type gf)
   nil)
 
 (defmethod compute-effective-slot-definition-initargs ((class virtual-slots-class) direct-slotds)
-  (if (eq (most-specific-slot-value direct-slotds 'allocation) :virtual)
-      (nconc 
-       (list :getter (most-specific-slot-value direct-slotds 'getter)
-	     :setter (most-specific-slot-value direct-slotds 'setter)
-	     :boundp (most-specific-slot-value direct-slotds 'boundp))
-       (call-next-method))
+  (if (typep (first direct-slotds) 'direct-virtual-slot-definition)
+      (let ((initargs ()))
+	(let ((getter (most-specific-slot-value direct-slotds 'getter)))
+	  (unless (eq getter *unbound-marker*)
+	    (setf (getf initargs :getter) getter)))
+	(let ((setter (most-specific-slot-value direct-slotds 'setter)))
+	  (unless (eq setter *unbound-marker*)
+	    (setf (getf initargs :setter) setter)))
+	(let ((unbound (most-specific-slot-value direct-slotds 'unbound)))
+	  (unless (eq unbound *unbound-marker*)
+	    (setf (getf initargs :unbound) unbound)))
+	(let ((boundp (most-specific-slot-value direct-slotds 'boundp)))
+	  (unless (eq boundp *unbound-marker*)
+	    (setf (getf initargs :boundp) boundp)))
+	(nconc initargs (call-next-method)))
     (call-next-method)))
 
 
@@ -155,28 +237,32 @@ (defmethod validate-superclass
 (internal *instance-cache*)
 (defvar *instance-cache* (make-hash-table :test #'eql))
 
-(defun cache-instance (instance)
+(defun cache-instance (instance &optional (weak-ref t))
   (setf
-   (gethash (system:sap-int (proxy-location instance)) *instance-cache*)
-   (ext:make-weak-pointer instance)))
+   (gethash (sap-int (foreign-location instance)) *instance-cache*)
+   (if weak-ref
+       (make-weak-pointer instance)
+     instance)))
 
 (defun find-cached-instance (location)
-  (let ((ref (gethash (system:sap-int location) *instance-cache*)))
+  (let ((ref (gethash (sap-int location) *instance-cache*)))
     (when ref
-      (ext:weak-pointer-value ref))))
+      (if (weak-pointer-p ref)
+	  (weak-pointer-value ref)
+	ref))))
 
 (defun instance-cached-p (location)
-  (gethash (system:sap-int location) *instance-cache*))
+  (gethash (sap-int location) *instance-cache*))
 
 (defun remove-cached-instance (location)
-  (remhash (system:sap-int location) *instance-cache*))
+  (remhash (sap-int location) *instance-cache*))
 
 ;; For debuging
-(defun cached-instances ()
+(defun list-cached-instances ()
   (let ((instances ()))
     (maphash #'(lambda (location ref)
 		 (declare (ignore location))
-		 (push (ext:weak-pointer-value ref) instances))
+		 (push ref instances))
 	     *instance-cache*)
     instances))
 			
@@ -184,56 +270,63 @@ (defun cached-instances ()
 
 ;;;; Proxy for alien instances
 
+;; TODO: add a ref-counted-proxy subclass
 (defclass proxy ()
-  ((location :reader proxy-location :type system-area-pointer)))
+  ((location :allocation :special :reader foreign-location :type pointer))
+  (:metaclass virtual-slots-class))
 
-(defgeneric initialize-proxy (object &rest initargs))
 (defgeneric instance-finalizer (object))
 (defgeneric reference-foreign (class location))
 (defgeneric unreference-foreign (class location))
+(defgeneric invalidate-instance (object))
+
+(defmethod reference-foreign ((name symbol) location)
+  (reference-foreign (find-class name) location))
+
+(defmethod unreference-foreign ((name symbol) location)
+  (unreference-foreign (find-class name) location))
 
 (defmethod unreference-foreign :around ((class class) location)
   (unless (null-pointer-p location)
-;;     (format t "Unreferencing ~A at ~A" (class-name class) location)
-;;     (finish-output *standard-output*)
-    (call-next-method)
-;;     (write-line " done")
-;;     (finish-output *standard-output*)
-    ))
-
-(defmethod print-object ((instance proxy) stream)
-  (print-unreadable-object (instance stream :type t :identity nil)
-    (format stream "at 0x~X" (sap-int (proxy-location instance)))))
+    (call-next-method)))
 
 (defmethod print-object ((instance proxy) stream)
   (print-unreadable-object (instance stream :type t :identity nil)
-    (format stream "at 0x~X" (sap-int (proxy-location instance)))))
+    (if (slot-boundp instance 'location)
+	(format stream "at 0x~X" (sap-int (foreign-location instance)))
+      (write-string "at \"unbound\"" stream))))
 
-
-(defmethod initialize-instance :around ((instance proxy) &key location)
-  (if location
-      (setf (slot-value instance 'location) location)      
-    (call-next-method))
-  (cache-instance instance)
-  (ext:finalize instance (instance-finalizer instance))
-  instance)
+(defmethod initialize-instance :around ((instance proxy) &rest initargs)
+  (declare (ignore initargs))
+  (prog1
+      (call-next-method)
+    (cache-instance instance)
+    (finalize instance (instance-finalizer instance))))
 
 (defmethod instance-finalizer ((instance proxy))
-  (let ((location (proxy-location instance))
+  (let ((location (foreign-location instance))
 	(class (class-of instance)))    
 ;;     (unless (find-method #'unreference-foreign nil (list (class-of class) t) nil)
 ;;       (error "No matching method for UNREFERENCE-INSTANCE when called with class ~A" class))
     #'(lambda ()
-	(when (instance-cached-p location)
-	  (remove-cached-instance location))
+	(remove-cached-instance location)
 	(unreference-foreign class location))))
 
+(defmethod invalidate-instance ((instance proxy))
+  (remove-cached-instance (foreign-location instance))
+  (slot-makunbound instance 'location))
+
 
 ;;;; Metaclass used for subclasses of proxy
 
+(defgeneric most-specific-proxy-superclass (class))
+(defgeneric direct-proxy-superclass (class))
+(defgeneric compute-foreign-size (class))
+  
+
 (eval-when (:compile-toplevel :load-toplevel :execute)
   (defclass proxy-class (virtual-slots-class)
-    ((size :reader proxy-instance-size)))
+    ((size :reader foreign-size)))
 
   (defclass direct-alien-slot-definition (direct-virtual-slot-definition)
     ((allocation :initform :alien)
@@ -242,30 +335,27 @@   (defclass direct-alien-slot-definition (direct-virtual-slot-definition)
   (defclass effective-alien-slot-definition (effective-virtual-slot-definition)
     ((offset :reader slot-definition-offset :initarg :offset)))
 
-
   (defmethod most-specific-proxy-superclass ((class proxy-class))
     (find-if
      #'(lambda (class)
 	 (subtypep (class-name class) 'proxy))
      (cdr (compute-class-precedence-list class))))
-  
+
   (defmethod direct-proxy-superclass ((class proxy-class))
     (find-if
      #'(lambda (class)
 	 (subtypep (class-name class) 'proxy))
      (class-direct-superclasses class)))
   
-  (defmethod shared-initialize ((class proxy-class) names
-				&rest initargs &key size)
-    (declare (ignore initargs))
+  (defmethod shared-initialize ((class proxy-class) names &key size)
     (call-next-method)
     (cond
       (size (setf (slot-value class 'size) (first size)))
       ((slot-boundp class 'size) (slot-makunbound class 'size))))
-  
+
   (defmethod direct-slot-definition-class ((class proxy-class) &rest initargs)
     (case (getf initargs :allocation)
-      ((nil :alien) (find-class 'direct-alien-slot-definition))
+      (:alien (find-class 'direct-alien-slot-definition))
       (t (call-next-method))))
   
   (defmethod effective-slot-definition-class ((class proxy-class) &rest initargs)
@@ -285,62 +375,71 @@   (defmethod compute-effective-slot-definition-initargs ((class proxy-class) dir
   (defmethod initialize-internal-slot-functions ((slotd effective-alien-slot-definition))
     (with-slots (offset) slotd
       (let ((type (slot-definition-type slotd)))
-	(unless (slot-boundp slotd 'reader-function)
+	(unless (slot-boundp slotd 'getter)
 	  (let ((reader (reader-function type)))
 	    (setf 
-	     (slot-value slotd 'reader-function)
+	     (slot-value slotd 'getter)
 	     #'(lambda (object)
-		 (funcall reader (proxy-location object) offset)))))
+		 (funcall reader (foreign-location object) offset)))))
 
-	(unless (slot-boundp slotd 'writer-function)
+	(unless (slot-boundp slotd 'setter)
 	  (let ((writer (writer-function type))
 		(destroy (destroy-function type)))
 	    (setf 
-	     (slot-value slotd 'writer-function)
+	     (slot-value slotd 'setter)
 	     #'(lambda (value object)
-		 (let ((location (proxy-location object)))
+		 (let ((location (foreign-location object)))
 		   (funcall destroy location offset) ; destroy old value
-		   (funcall writer value location offset))))))
+		   (funcall writer value location offset))))))))
 
-	(unless (slot-boundp slotd 'boundp-function)
-	  (setf 
-	   (slot-value slotd 'boundp-function)
-	   #'(lambda (object)
-	       (declare (ignore object))
-	       t)))))
     (call-next-method))
   
+  (defmethod compute-foreign-size ((class proxy-class))
+    nil)
 
   ;; TODO: call some C code to detect this a compile time
   (defconstant +struct-alignmen+ 4)
 
+  (defun align-offset (size)
+    (if (zerop (mod size +struct-alignmen+))
+	size
+      (+ size (- +struct-alignmen+ (mod size +struct-alignmen+)))))
+
   (defmethod compute-slots ((class proxy-class))
-    (loop 
-     with offset = (proxy-instance-size (most-specific-proxy-superclass class))
-     with size = offset
-     for slotd in (class-direct-slots class)
-     when (eq (slot-definition-allocation slotd) :alien)
-     do (if (not (slot-boundp slotd 'offset))
-	    (setf (slot-value slotd 'offset) offset)
-	  (setq offset (slot-value slotd 'offset)))
-
-        (incf offset (size-of (slot-definition-type slotd)))
-	(incf offset (mod offset +struct-alignmen+))
-	(setq size (max size offset))
-
-     finally (unless (slot-boundp class 'size)
-	       (setf (slot-value class 'size) size)))
+    (let ((alien-slots 
+	   (remove-if-not
+	    #'(lambda (slotd)
+		(eq (slot-definition-allocation slotd) :alien))
+	    (class-direct-slots class))))      
+      (when alien-slots
+	(loop 
+	 as offset = (align-offset (foreign-size 
+				    (most-specific-proxy-superclass class)))
+	             then (align-offset 
+			   (+ 
+			    (slot-definition-offset slotd)
+			    (size-of (slot-definition-type slotd))))
+       for slotd in alien-slots
+       unless (slot-boundp slotd 'offset)
+       do (setf (slot-value slotd 'offset) offset))))
     (call-next-method))
 
+  (defmethod compute-slots :after ((class proxy-class))
+    (when (and (class-finalized-p class) (not (slot-boundp class 'size)))
+      (let ((size (compute-foreign-size class)))
+	(when size 
+	  (setf (slot-value class 'size) size)))))
   
   (defmethod validate-superclass ((class proxy-class) (super standard-class))
     (subtypep (class-name super) 'proxy))
   
-  (defmethod proxy-instance-size (class)
-    (declare (ignore class))
-    0)
-)
+  (defmethod foreign-size ((class-name symbol))
+    (foreign-size (find-class class-name))))
+
+(defmethod foreign-size ((object proxy))
+  (foreign-size (class-of object)))
   
+
 (defmethod alien-type ((class proxy-class) &rest args)
   (declare (ignore class args))
   (alien-type 'pointer))
@@ -360,11 +459,31 @@ (defmethod from-alien-function ((class proxy-class) &rest args)
 
 (defmethod to-alien-form (instance (class proxy-class) &rest args)
   (declare (ignore class args))
-  `(proxy-location ,instance))
+  `(foreign-location ,instance))
 
 (defmethod to-alien-function ((class proxy-class) &rest args)
   (declare (ignore class args))
-  #'proxy-location)
+  #'foreign-location)
+
+(defmethod copy-from-alien-form (location (class proxy-class) &rest args)
+  (declare (ignore args))
+  (let ((class-name (class-name class)))
+    `(ensure-proxy-instance ',class-name
+      (reference-foreign ',class-name ,location))))
+
+(defmethod copy-from-alien-function ((class proxy-class) &rest args)
+  (declare (ignore args))  
+  #'(lambda (location)
+      (ensure-proxy-instance class (reference-foreign class location))))
+
+(defmethod copy-to-alien-form (instance (class proxy-class) &rest args)
+  (declare (ignore args))
+  `(reference-foreign ',(class-name class) (foreign-location ,instance)))
+
+(defmethod copy-to-alien-function ((class proxy-class) &rest args)
+  (declare (ignore args))
+  #'(lambda (instance)
+      (reference-foreign class (foreign-location instance))))
 
 (defmethod writer-function ((class proxy-class) &rest args)
   (declare (ignore args))
@@ -372,46 +491,68 @@ (defmethod writer-function ((class proxy-class) &rest args)
       (assert (null-pointer-p (sap-ref-sap location offset)))
       (setf 
        (sap-ref-sap location offset)
-       (reference-foreign class (proxy-location instance)))))
+       (reference-foreign class (foreign-location instance)))))
 
 (defmethod reader-function ((class proxy-class) &rest args)
   (declare (ignore args))
   #'(lambda (location &optional (offset 0))
-      (ensure-proxy-instance class (sap-ref-sap location offset))))
+      (let ((instance (sap-ref-sap location offset)))
+	(unless (null-pointer-p instance)
+	  (ensure-proxy-instance class (reference-foreign class instance))))))
 
 (defmethod destroy-function ((class proxy-class) &rest args)
   (declare (ignore args))
   #'(lambda (location &optional (offset 0))
       (unreference-foreign class (sap-ref-sap location offset))))
 
+(defmethod unbound-value ((class proxy-class) &rest args)
+  (declare (ignore args))
+  (values t nil))
 
-(defgeneric ensure-proxy-instance (class location)
-  (:documentation "Returns a proxy object representing the foreign object at the give location."))
-
-(defmethod ensure-proxy-instance :around (class location)
+(defun ensure-proxy-instance (class location &rest initargs)
+  "Returns a proxy object representing the foreign object at the give
+location. If an existing object is not found in the cache
+MAKE-PROXY-INSTANCE is called to create one."
   (unless (null-pointer-p location)
     (or 
-     (find-cached-instance location)
-     (call-next-method))))
-  
-(defmethod ensure-proxy-instance ((class symbol) location)
-  (ensure-proxy-instance (find-class class) location))
-
-(defmethod ensure-proxy-instance ((class proxy-class) location)
-  (make-instance class :location location))
+     (let ((instance (find-cached-instance location)))
+       (when instance
+	 (format t "Object found in cache: ~A~%" instance)
+	 instance))
+     (let ((instance (apply #'make-proxy-instance class location initargs)))
+       (cache-instance instance)
+       instance))))
+
+(defgeneric make-proxy-instance (class location &key weak)
+  (:documentation "Creates a new proxy object representing the foreign
+object at the give location. If WEAK is non NIL the foreign memory
+will not be released when the proxy is garbage collected."))
+
+(defmethod make-proxy-instance ((class symbol) location &rest initargs)
+  (apply #'make-proxy-instance (find-class class) location initargs))
+
+(defmethod make-proxy-instance ((class proxy-class) location &key weak)
+  (let ((instance (allocate-instance class)))
+    (setf (slot-value instance 'location) location)
+    (unless weak
+      (finalize instance (instance-finalizer instance)))
+    instance))
 
 
 ;;;; Superclasses for wrapping of C structures
 
 (defclass struct (proxy)
   ()
-  (:metaclass proxy-class))
+  (:metaclass proxy-class)
+  (:size 0))
 
 (defmethod initialize-instance ((struct struct) &rest initargs)
   (declare (ignore initargs))
-  (setf 
-   (slot-value struct 'location)
-   (allocate-memory (proxy-instance-size (class-of struct))))
+  (unless (slot-boundp struct 'location)
+    (let ((size (foreign-size (class-of struct))))
+      (if (zerop size)
+	  (error "~A has zero size" (class-of struct))
+	(setf (slot-value struct 'location) (allocate-memory size)))))
   (call-next-method))
 
 
@@ -420,18 +561,32 @@ (defmethod initialize-instance ((struct struct) &rest initargs)
 (defclass struct-class (proxy-class)
   ())
 
+(defmethod direct-slot-definition-class ((class struct-class) &rest initargs)
+  (if (not (getf initargs :allocation))
+      (find-class 'direct-alien-slot-definition)
+    (call-next-method)))
+
 (defmethod reference-foreign ((class struct-class) location)
-  (copy-memory location (proxy-instance-size class)))
+  (copy-memory location (foreign-size class)))
 
 (defmethod unreference-foreign ((class struct-class) location)
   (deallocate-memory location))
 
-(defmethod reader-function ((class struct-class) &rest args)
+(defmethod compute-foreign-size ((class struct-class))
+  (let ((size (loop
+	       for slotd in (class-slots class)
+	       when (eq (slot-definition-allocation slotd) :alien)
+	       maximize (+ 
+			 (slot-definition-offset slotd)
+			 (size-of (slot-definition-type slotd))))))
+    (+ size (mod size +struct-alignmen+))))
+
+(defmethod weak-reader-function ((class struct-class) &rest args)
   (declare (ignore args))
   #'(lambda (location &optional (offset 0))
       (let ((instance (sap-ref-sap location offset)))
 	(unless (null-pointer-p instance)
-	  (ensure-proxy-instance class (reference-foreign class instance))))))
+	  (ensure-proxy-instance class instance :weak t)))))
 
 
 (defclass static-struct-class (struct-class)
@@ -444,3 +599,30 @@ (defmethod reference-foreign ((class static-struct-class) location)
 (defmethod unreference-foreign ((class static-struct-class) location)
   (declare (ignore class location))
   nil)
+
+
+;;; Pseudo type for structs which are inlined in other objects
+
+(defmethod size-of ((type (eql 'inlined)) &rest args)
+  (declare (ignore type))
+  (foreign-size (first args)))
+
+(defmethod reader-function ((type (eql 'inlined)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (class) args
+    #'(lambda (location &optional (offset 0))
+	(ensure-proxy-instance class 
+	 (reference-foreign class (sap+ location offset))))))
+
+(defmethod writer-function ((type (eql 'inlined)) &rest args)
+  (declare (ignore type))
+  (destructuring-bind (class) args
+    #'(lambda (instance location &optional (offset 0))
+	(copy-memory (foreign-location instance) (foreign-size class) (sap+ location offset)))))
+
+(defmethod destroy-function ((type (eql 'inlined)) &rest args)
+  (declare (ignore args))
+  #'(lambda (location &optional (offset 0))
+      (declare (ignore location offset))))
+
+(export 'inlined)