Added caching of invalidated proxy instances

[clg] / glib / proxy.lisp

diff --git a/glib/proxy.lisp b/glib/proxy.lisp
index f4c5a59ba5294cd5b86b284401d7d0b863cf83b8..aad291858a80361be4cacf00ba610b5106cb2bf8 100644 (file)
--- a/glib/proxy.lisp
+++ b/glib/proxy.lisp
@@ -1,422 +1,669 @@
-;; 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 1.1 2001-04-29 20:19:25 espen Exp $
+;; $Id: proxy.lisp,v 1.29 2006-02-07 13:20:39 espen Exp $

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

-

 ;;;; Superclass for all metaclasses implementing some sort of virtual slots
 
 (eval-when (:compile-toplevel :load-toplevel :execute)
 ;;;; Superclass for all metaclasses implementing some sort of virtual slots
 
 (eval-when (:compile-toplevel :load-toplevel :execute)

-  (defclass virtual-class (pcl::standard-class))
+  (defclass virtual-slots-class (standard-class) 
+    ())

 
   (defclass direct-virtual-slot-definition (standard-direct-slot-definition)
 
   (defclass direct-virtual-slot-definition (standard-direct-slot-definition)

-    ((location
-      :reader slot-definition-location
-      :initarg :location)))
+    ((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)))
+  (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)))
+
+  (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 direct-slot-definition-class ((class virtual-class) initargs)
-  (if (eq (getf initargs :allocation) :virtual)
-      (find-class 'direct-virtual-slot-definition)
-    (call-next-method)))
-
-
-(defmethod effective-slot-definition-class ((class virtual-class) initargs)
-  (if (eq (getf initargs :allocation) :virtual)
-      (find-class 'effective-virtual-slot-definition)
-    (call-next-method)))
+(defmethod initialize-instance ((slotd effective-special-slot-definition) &rest initargs)
+  (declare (ignore initargs))
+  (call-next-method)
+  (setf (slot-value slotd 'allocation) :instance))

 
 
 
 

-(defun %direct-slot-definitions-slot-value (slotds slot &optional default)
-  (let ((slotd
-        (find-if
-         #'(lambda (slotd)
-             (and
-              (slot-exists-p slotd slot)
-              (slot-boundp slotd slot)))
-         slotds)))
-    (if slotd
-       (slot-value slotd slot)
-      default)))
-  
+(defmethod direct-slot-definition-class ((class virtual-slots-class) &rest initargs)
+  (case (getf initargs :allocation)
+    (:virtual (find-class 'direct-virtual-slot-definition))
+    (:special (find-class 'direct-special-slot-definition))
+    (t (call-next-method))))

 
 

-(defgeneric compute-virtual-slot-location (class slotd direct-slotds))
+(defmethod effective-slot-definition-class ((class virtual-slots-class) &rest initargs)
+  (case (getf initargs :allocation)
+    (:virtual (find-class 'effective-virtual-slot-definition))
+    (:special (find-class 'effective-special-slot-definition))
+    (t (call-next-method))))

 
 

-(defmethod compute-virtual-slot-location
-    ((class virtual-class)
-     (slotd effective-virtual-slot-definition)
-     direct-slotds)
-    (let ((location
-          (%direct-slot-definitions-slot-value direct-slotds 'location)))
-      (if (and location (symbolp location))
-         (list location `(setf ,location))
-       location)))

 
 

+(defmethod initialize-internal-slot-functions ((slotd effective-virtual-slot-definition))
+  (if (not (slot-boundp slotd 'getter))
+      (setf
+       (slot-value slotd 'reader-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 '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))))

 
 

-(defmethod compute-effective-slot-definition
-    ((class virtual-class) direct-slotds)
-  (let ((slotd (call-next-method)))
-    (when (typep slotd 'effective-virtual-slot-definition)

       (setf
       (setf

-       (slot-value slotd 'pcl::location)
-       (compute-virtual-slot-location class slotd direct-slotds)))
-    slotd))
+       (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)
+        ((or symbol cons) 
+         #'(lambda (value object)
+             (funcall (fdefinition setter) value object)))
+        (string
+         (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)
+  nil)
+
+(defmethod compute-effective-slot-definition-initargs ((class virtual-slots-class) direct-slotds)
+  (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)))

 
 
 (defmethod slot-value-using-class
 
 
 (defmethod slot-value-using-class

-    ((class virtual-class) (object standard-object)
+    ((class virtual-slots-class) (object standard-object)

      (slotd effective-virtual-slot-definition))
      (slotd effective-virtual-slot-definition))

-  (let ((reader (first (slot-definition-location slotd))))
-    (if reader
-       (funcall reader object)
-      (slot-unbound class object (slot-definition-name slotd)))))
-
+  (if (funcall (slot-value slotd 'boundp-function) object)
+      (funcall (slot-value slotd 'reader-function) object)
+    (slot-unbound class object (slot-definition-name slotd))))

 
 (defmethod slot-boundp-using-class
 
 (defmethod slot-boundp-using-class

-    ((class virtual-class) (object standard-object)
+    ((class virtual-slots-class) (object standard-object)

      (slotd effective-virtual-slot-definition))
      (slotd effective-virtual-slot-definition))

-   (and (first (slot-definition-location slotd)) t))
-    
-
-
-(defmethod (setf slot-value-using-class)
-    (value (class virtual-class) (object standard-object)
+  (funcall (slot-value slotd 'boundp-function) object))
+  
+(defmethod (setf slot-value-using-class) 
+    (value (class virtual-slots-class) (object standard-object)

      (slotd effective-virtual-slot-definition))
      (slotd effective-virtual-slot-definition))

-  (let ((writer (second (slot-definition-location slotd))))
-    (cond
-     ((null writer)
-      (error
-       "Can't set read-only slot ~A in ~A"
-       (slot-definition-name slotd)
-       object))
-     ((or (functionp writer) (symbolp writer))
-      (funcall writer value object)
-      value)
-     (t
-      (funcall (fdefinition writer) value object)
-      value))))
-       
+  (funcall (slot-value slotd 'writer-function) value object))

 
 

+  

 (defmethod validate-superclass
 (defmethod validate-superclass

-    ((class virtual-class) (super pcl::standard-class))
+    ((class virtual-slots-class) (super standard-class))

   t)
 
 
 ;;;; Proxy cache
 
   t)
 
 
 ;;;; Proxy cache
 

-(internal *instance-cache*)

 (defvar *instance-cache* (make-hash-table :test #'eql))
 
 (defvar *instance-cache* (make-hash-table :test #'eql))
 

-(defun cache-instance (instance)
+(defun cache-instance (instance &optional (weak-ref t))

   (setf
   (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)
 
 (defun find-cached-instance (location)

-  (let ((ref (gethash (system:sap-int location) *instance-cache*)))
+  (let ((ref (gethash (sap-int location) *instance-cache*)))

     (when ref
     (when ref

-      (ext:weak-pointer-value ref))))
+      (if (weak-pointer-p ref)
+         (weak-pointer-value ref)
+       ref))))
+
+(defun instance-cached-p (location)
+  (gethash (sap-int location) *instance-cache*))

 
 (defun remove-cached-instance (location)
 
 (defun remove-cached-instance (location)

-  (remhash (system:sap-int location) *instance-cache*))
+  (remhash (sap-int location) *instance-cache*))
+
+;; For debuging
+(defun list-cached-instances ()
+  (let ((instances ()))
+    (maphash #'(lambda (location ref)
+                (declare (ignore location))
+                (push ref instances))
+            *instance-cache*)
+    instances))
+                       
+;; Instances that gets invalidated tend to be short lived, but created
+;; in large numbers. So we're keeping them in a hash table to be able
+;; to reuse them (and thus reduce consing)
+(defvar *invalidated-instance-cache* (make-hash-table :test #'eql))
+
+(defun cache-invalidated-instance (instance)
+  (push instance
+   (gethash (class-of instance) *invalidated-instance-cache*)))
+
+(defun find-invalidated-instance (class)
+  (when (gethash class *invalidated-instance-cache*)
+    (pop (gethash class *invalidated-instance-cache*))))
+
+(defun list-invalidated-instances ()
+  (let ((instances ()))
+    (maphash #'(lambda (location ref)
+                (declare (ignore location))
+                (push ref instances))
+            *invalidated-instance-cache*)
+    instances))

 
 
 
 ;;;; Proxy for alien instances
 
 
 
 
 ;;;; Proxy for alien instances
 

-(eval-when (:compile-toplevel :load-toplevel :execute)
-  (defclass proxy ()
-    ((location
-      :reader proxy-location
-      :type system-area-pointer)))
+;; TODO: add a ref-counted-proxy subclass
+(defclass proxy ()
+  ((location :allocation :special :reader foreign-location :type pointer))
+  (:metaclass virtual-slots-class))

 
 

-  (defgeneric initialize-proxy (object &rest initargs))
-  (defgeneric instance-finalizer (object)))
+(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 initialize-instance :after ((instance proxy)
-                                      &rest initargs &key)
-  (declare (ignore initargs))
-  (cache-instance instance)
-  (ext:finalize instance (instance-finalizer instance)))
+(defmethod unreference-foreign ((name symbol) location)
+  (unreference-foreign (find-class name) location))

 
 

+(defmethod unreference-foreign :around ((class class) location)
+  (unless (null-pointer-p location)
+    (call-next-method)))

 
 

-(defmethod initialize-proxy ((instance proxy)
-                            &rest initargs)
-  (declare (ignore initargs))
-  (cache-instance instance))
+(defmethod print-object ((instance proxy) stream)
+  (print-unreadable-object (instance stream :type t :identity nil)
+    (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) &rest initargs)
+  (declare (ignore initargs))
+  (prog1
+      (call-next-method)
+    (cache-instance instance)
+    (finalize instance (instance-finalizer instance))))

 
 (defmethod instance-finalizer ((instance proxy))
 
 (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 ()
     #'(lambda ()

-       (remove-cached-instance location))))
-
-
-(deftype-method translate-type-spec proxy (type-spec)
-  (declare (ignore type-spec))
-  (translate-type-spec 'pointer))
-
-(deftype-method size-of proxy (type-spec)
-  (declare (ignore type-spec))
-  (size-of 'pointer))
-
-(deftype-method translate-from-alien
-    proxy (type-spec location &optional weak-ref)
-  `(let ((location ,location))
-     (unless (null-pointer-p location)
-       (ensure-proxy-instance ',type-spec location ,weak-ref))))
+       (remove-cached-instance location)
+       (unreference-foreign class location))))

 
 

+;; Any reference to the foreign object the instance may have held
+;; should be released before this method is invoked
+(defmethod invalidate-instance ((instance proxy))
+  (remove-cached-instance (foreign-location instance))
+  (slot-makunbound instance 'location)
+  (cancel-finalization instance)
+  (cache-invalidated-instance instance))

 
 
 ;;;; Metaclass used for subclasses of proxy
 
 
 
 ;;;; 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)
 (eval-when (:compile-toplevel :load-toplevel :execute)

-  (defclass proxy-class (virtual-class)
-    ((size :reader proxy-class-instance-size)))
+  (defclass proxy-class (virtual-slots-class)
+    ((size :reader foreign-size)))

 
   (defclass direct-alien-slot-definition (direct-virtual-slot-definition)
 
   (defclass direct-alien-slot-definition (direct-virtual-slot-definition)

-    ((allocation
-      :initform :alien)
-     (offset
-      :reader slot-definition-offset
-      :initarg :offset
-      :initform 0)))
+    ((allocation :initform :alien)
+     (offset :reader slot-definition-offset :initarg :offset)))

   
   (defclass effective-alien-slot-definition (effective-virtual-slot-definition)
   
   (defclass effective-alien-slot-definition (effective-virtual-slot-definition)

-    ((offset :reader slot-definition-offset)))
-  
-  (defclass effective-virtual-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))
 
   (defmethod most-specific-proxy-superclass ((class proxy-class))
     (find-if
      #'(lambda (class)
         (subtypep (class-name class) 'proxy))

-     (cdr (pcl::compute-class-precedence-list class))))
-
+     (cdr (compute-class-precedence-list class))))

 
 

-  (defmethod shared-initialize ((class proxy-class) names
-                               &rest initargs &key size name)
-    (declare (ignore initargs))
+  (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 &key size)

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

-    (when size
-      (setf (slot-value class 'size) (first size))))
-    
-
-  (defmethod shared-initialize :after ((class proxy-class) names
-                                      &rest initargs &key)
-    (declare (ignore initargs names))
-    (let* ((super (most-specific-proxy-superclass class))
-          (actual-size
-           (if (eq (class-name super) 'proxy)
-               0
-             (proxy-class-instance-size super))))
-      (dolist (slotd (class-slots class))
-       (when (eq (slot-definition-allocation slotd) :alien)
-         (with-slots (offset type) slotd
-           (setq actual-size (max actual-size (+ offset (size-of type)))))))
-      (cond
-       ((not (slot-boundp class 'size))
-       (setf (slot-value class 'size) actual-size))
-       ((> actual-size (slot-value class 'size))
-       (warn "The actual size of class ~A is lager than specified" class)))))
-
-
-  (defmethod direct-slot-definition-class ((class proxy-class) initargs)
+    (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)
     (case (getf initargs :allocation)

-      ((nil :alien) (find-class 'direct-alien-slot-definition))
-;      (:instance (error "Allocation :instance not allowed in class ~A" class))
+      (:alien (find-class 'direct-alien-slot-definition))

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

-
-
-  (defmethod effective-slot-definition-class ((class proxy-class) initargs)
+  
+  (defmethod effective-slot-definition-class ((class proxy-class) &rest initargs)

     (case (getf initargs :allocation)
       (:alien (find-class 'effective-alien-slot-definition))
     (case (getf initargs :allocation)
       (:alien (find-class 'effective-alien-slot-definition))

-      (:virtual (find-class 'effective-virtual-alien-slot-definition))

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

-  (defmethod compute-virtual-slot-location
-      ((class proxy-class) (slotd effective-alien-slot-definition)
-       direct-slotds)
-    (with-slots (offset type) slotd
-      (setf offset (%direct-slot-definitions-slot-value direct-slotds 'offset))
-      (let ((reader (intern-reader-function type))
-           (writer (intern-writer-function type))
-           (destroy (intern-destroy-function type)))
-       (list
-        #'(lambda (object)
-            (funcall reader (proxy-location object) offset))
-        #'(lambda (value object)
-            (let ((location (proxy-location object)))
-              (funcall destroy location offset)
-              (funcall writer value location offset)))))))
-            
+  (defmethod compute-effective-slot-definition-initargs ((class proxy-class) direct-slotds)
+    (if (eq (most-specific-slot-value direct-slotds 'allocation) :alien)
+       (nconc 
+        (list :offset (most-specific-slot-value direct-slotds 'offset))
+        (call-next-method))
+      (call-next-method)))

   
   

-  (defmethod compute-virtual-slot-location
-      ((class proxy-class)
-       (slotd effective-virtual-alien-slot-definition)
-       direct-slotds)
-    (let ((location (call-next-method)))
-      (if (or (stringp location) (consp location))
-         (destructuring-bind (reader &optional writer) (mklist location)
-           (with-slots (type) slotd
-              (list
-              (if (stringp reader)
-                  (let* ((alien-type (translate-type-spec type))
-                         (alien
-                          (alien::%heap-alien
-                           (alien::make-heap-alien-info
-                            :type (alien::parse-alien-type
-                                   `(function ,alien-type system-area-pointer))
-                            :sap-form (system:foreign-symbol-address reader))))
-                         (translate-return-value
-                          (intern-return-value-translator type)))
-                    #'(lambda (object)
-                        (funcall
-                         translate-return-value
-                         (alien-funcall
-                          alien (proxy-location object)))))
-                reader)
-              (if (stringp writer)
-                  (let* ((alien-type (translate-type-spec type))
-                         (alien
-                          (alien::%heap-alien
-                           (alien::make-heap-alien-info
-                            :type (alien::parse-alien-type
-                                   `(function
-                                     void system-area-pointer ,alien-type))
-                            :sap-form (system:foreign-symbol-address writer))))
-                         (translate-argument (intern-argument-translator type))
-                         (cleanup (intern-cleanup-function type)))
-                    #'(lambda (value object)
-                        (let ((tmp (funcall translate-argument value))
-                              (location (proxy-location object)))
-                          (alien-funcall alien location tmp)
-                          (funcall cleanup tmp))))
-                writer))))
-       location)))

 
 

+  (defmethod initialize-internal-slot-functions ((slotd effective-alien-slot-definition))
+    (with-slots (offset) slotd
+      (let ((type (slot-definition-type slotd)))
+       (unless (slot-boundp slotd 'getter)
+         (let ((reader (reader-function type)))
+           (setf 
+            (slot-value slotd 'getter)
+            #'(lambda (object)
+                (funcall reader (foreign-location object) offset)))))
+
+       (unless (slot-boundp slotd 'setter)
+         (let ((writer (writer-function type))
+               (destroy (destroy-function type)))
+           (setf 
+            (slot-value slotd 'setter)
+            #'(lambda (value object)
+                (let ((location (foreign-location object)))
+                  (funcall destroy location offset) ; destroy old value
+                  (funcall writer value location offset))))))))

 
 

-  (defmethod compute-slots ((class proxy-class))
-    ;; Translating the user supplied relative (to previous slot) offsets
-    ;; to absolute offsets.
-    ;; This code is broken and have to be fixed.
-    (with-slots (direct-slots) class
-      (let* ((super (most-specific-proxy-superclass class))
-            (slot-offset
-             (if (eq (class-name super) 'proxy)
-                 0
-               (proxy-class-instance-size super))))
-       (dolist (slotd direct-slots)
-         (when (eq (slot-definition-allocation slotd) :alien)
-           (with-slots (offset type) slotd
-             (setf
-              offset (+ slot-offset offset)
-              slot-offset (+ offset (size-of type)))))))
-    
-      ;; Reverse the direct slot definitions so the effective slots
-      ;; will be in correct order.
-      (setf direct-slots (reverse direct-slots))
-      ;; This nreverse caused me so much frustration that I leave it
-      ;; here just as a reminder of what not to do.
-;      (setf direct-slots (nreverse direct-slots))
-      )

     (call-next-method))
     (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)

 
 

-  (defmethod validate-superclass ((class proxy-class)
-                                 (super pcl::standard-class))
-     (subtypep (class-name super) 'proxy))
-
-  (defgeneric make-proxy-instance (class location weak-ref &rest initargs &key)))
-
+  (defun align-offset (size)
+    (if (zerop (mod size +struct-alignmen+))
+       size
+      (+ size (- +struct-alignmen+ (mod size +struct-alignmen+)))))

 
 

-(defmethod make-proxy-instance ((class symbol) location weak-ref
-                               &rest initargs &key)
-  (apply #'make-proxy-instance (find-class class) location weak-ref initargs))
+  (defmethod compute-slots ((class proxy-class))
+    (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 make-proxy-instance ((class proxy-class) location weak-ref
-                               &rest initargs &key)
-  (let ((instance (allocate-instance class)))
-    (apply
-     #'initialize-proxy
-     instance :location location :weak-ref weak-ref initargs)
-    instance))
+  (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 foreign-size ((class-name symbol))
+    (foreign-size (find-class class-name))))

 
 

-(defun ensure-proxy-instance (class location weak-ref &rest initargs)
-  (or
-   (find-cached-instance location)
-   (apply #'make-proxy-instance class location weak-ref initargs)))
+(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))

 
 

-;;;; Superclass for wrapping of C structures
+(defmethod size-of ((class proxy-class) &rest args)
+  (declare (ignore class args))
+  (size-of 'pointer))

 
 

-(eval-when (:compile-toplevel :load-toplevel :execute)
-  (defclass alien-structure (proxy)
-    ()
-    (:metaclass proxy-class)
-    (:size 0)))
+(defmethod from-alien-form (location (class proxy-class) &rest args)
+  (declare (ignore args))
+  `(ensure-proxy-instance ',(class-name class) ,location))
+
+(defmethod from-alien-function ((class proxy-class) &rest args)
+  (declare (ignore args))  
+  #'(lambda (location)
+      (ensure-proxy-instance class location)))
+
+(defmethod to-alien-form (instance (class proxy-class) &rest args)
+  (declare (ignore class args))
+  `(foreign-location ,instance))
+
+(defmethod to-alien-function ((class proxy-class) &rest args)
+  (declare (ignore class args))
+  #'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))
+  #'(lambda (instance location &optional (offset 0))
+      (assert (null-pointer-p (sap-ref-sap location offset)))
+      (setf 
+       (sap-ref-sap location offset)
+       (reference-foreign class (foreign-location instance)))))
+
+(defmethod reader-function ((class proxy-class) &rest args)
+  (declare (ignore args))
+  #'(lambda (location &optional (offset 0) weak-p)
+      (declare (ignore weak-p))
+      (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))
+
+(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 
+     #-debug-ref-counting(find-cached-instance location)
+     #+debug-ref-counting
+     (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
+        (or
+         (find-invalidated-instance class)
+         (allocate-instance class))))
+    (setf (slot-value instance 'location) location)
+    (unless weak
+      (finalize instance (instance-finalizer instance)))
+    instance))

 
 
 
 

-(defmethod initialize-instance ((structure alien-structure)
-                               &rest initargs)
-  (declare (ignore initargs))
-  (setf 
-   (slot-value structure 'location)
-   (allocate-memory (proxy-class-instance-size (class-of structure))))
-  (call-next-method))
+;;;; Superclasses for wrapping of C structures

 
 

+(defclass struct (proxy)
+  ()
+  (:metaclass proxy-class)
+  (:size 0))

 
 

-(defmethod initialize-proxy ((structure alien-structure)
-                            &rest initargs &key location weak-ref)
+(defmethod initialize-instance ((struct struct) &rest initargs)

   (declare (ignore initargs))
   (declare (ignore initargs))

-  (setf
-   (slot-value structure 'location)
-   (if weak-ref
-       (copy-memory location (proxy-class-instance-size (class-of structure)))
-     location))
+  (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))
 
 
   (call-next-method))
 
 

-(defmethod instance-finalizer ((structure alien-structure))
-  (let ((location (proxy-location structure)))
-    (declare (type system-area-pointer location))
-    #'(lambda ()
-       (deallocate-memory location)
-       (remove-cached-instance location))))
-
+;;;; Metaclasses used for subclasses of struct

 
 

-(deftype-method translate-to-alien
-     alien-structure (type-spec object &optional weak-ref)
-  (if weak-ref
-      `(proxy-location ,object)
-    `(copy-memory
-      (proxy-location ,object)
-      ,(proxy-class-instance-size (find-class type-spec)))))
+(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)))

 
 

-(deftype-method unreference-alien alien-structure (type-spec c-struct)
-  (declare (ignore type-spec))
-  `(deallocate-memory ,c-struct))
+(defmethod reference-foreign ((class struct-class) location)
+  (copy-memory location (foreign-size class)))
+
+(defmethod unreference-foreign ((class struct-class) location)
+  (deallocate-memory location))
+
+(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 reader-function ((class struct-class) &rest args)
+  (declare (ignore args))
+  #'(lambda (location &optional (offset 0) weak-p)
+      (let ((instance (sap-ref-sap location offset)))
+       (unless (null-pointer-p instance)
+         (if weak-p
+             (ensure-proxy-instance class instance :weak t)
+           (ensure-proxy-instance class (reference-foreign class instance)))))))
+
+
+(defclass static-struct-class (struct-class)
+  ())
+
+(defmethod reference-foreign ((class static-struct-class) location)
+  (declare (ignore class))
+  location)
+
+(defmethod unreference-foreign ((class static-struct-class) location)
+  (declare (ignore class location))
+  nil)
+
+(defmethod reader-function ((class struct-class) &rest args)
+  (declare (ignore args))
+  #'(lambda (location &optional (offset 0) weak-p)
+      (declare (ignore weak-p))
+      (let ((instance (sap-ref-sap location offset)))
+       (unless (null-pointer-p instance)
+         (ensure-proxy-instance class instance :weak t)))))
+
+
+;;; 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) weak-p)
+       (declare (ignore weak-p))
+       (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)