[clg] / glib / proxy.lisp

;; Common Lisp bindings for GTK+ v2.x
;; Copyright 2000-2005 Espen S. Johnsen <espen@users.sf.net>
;;
;; 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:
;;
;; The above copyright notice and this permission notice shall be
;; included in all copies or substantial portions of the Software.
;;
;; 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 1.23 2006/02/02 22:35:14 espen Exp $

(in-package "GLIB")

;;;; Superclass for all metaclasses implementing some sort of virtual slots

(eval-when (:compile-toplevel :load-toplevel :execute)
  (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)))

  (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)
  (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)
  (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))
  (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 (proxy-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 (proxy-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)
         ((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 (proxy-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
    ((class virtual-slots-class) (object standard-object)
     (slotd effective-virtual-slot-definition))
  (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
    ((class virtual-slots-class) (object standard-object)
     (slotd effective-virtual-slot-definition))
  (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))
  (funcall (slot-value slotd 'writer-function) value object))

  
(defmethod validate-superclass
    ((class virtual-slots-class) (super standard-class))
  t)


;;;; Proxy cache

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

(defun cache-instance (instance &optional (weak-ref t))
  (setf
   (gethash (sap-int (proxy-location instance)) *instance-cache*)
   (if weak-ref
       (make-weak-pointer instance)
     instance)))

(defun find-cached-instance (location)
  (let ((ref (gethash (sap-int location) *instance-cache*)))
    (when 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)
  (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))
                        


;;;; Proxy for alien instances

(defclass proxy ()
  ((location :allocation :special :reader proxy-location :type system-area-pointer))
  (:metaclass virtual-slots-class))

(defgeneric instance-finalizer (object))
(defgeneric reference-foreign (class location))
(defgeneric unreference-foreign (class location))

(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)
    (when (slot-boundp instance 'location)
      (format stream "at 0x~X" (sap-int (proxy-location instance))))))

(defmethod initialize-instance :around ((instance proxy) &key location)
  (if location
      (setf (slot-value instance 'location) location)      
    (call-next-method))
  (cache-instance instance)
  (finalize instance (instance-finalizer instance))
  instance)

(defmethod instance-finalizer ((instance proxy))
  (let ((location (proxy-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 ()
        (remove-cached-instance location)
        (unreference-foreign class location))))


;;;; Metaclass used for subclasses of proxy

(defgeneric most-specific-proxy-superclass (class))
(defgeneric direct-proxy-superclass (class))
  

(eval-when (:compile-toplevel :load-toplevel :execute)
  (defclass proxy-class (virtual-slots-class)
    ((size :reader proxy-instance-size)))

  (defclass direct-alien-slot-definition (direct-virtual-slot-definition)
    ((allocation :initform :alien)
     (offset :reader slot-definition-offset :initarg :offset)))
  
  (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 &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)
      (:alien (find-class 'direct-alien-slot-definition))
      (t (call-next-method))))
  
  (defmethod effective-slot-definition-class ((class proxy-class) &rest initargs)
    (case (getf initargs :allocation)
      (:alien (find-class 'effective-alien-slot-definition))
      (t (call-next-method))))
  
  
  (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 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 (proxy-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 (proxy-location object)))
                   (funcall destroy location offset) ; destroy old value
                   (funcall writer value location offset))))))))

    (call-next-method))
  

  ;; TODO: call some C code to detect this a compile time
  (defconstant +struct-alignmen+ 4)

  (defmethod compute-slots ((class proxy-class))
    (loop 
     with offset = (let ((size-of-super-classes
                          (proxy-instance-size 
                           (most-specific-proxy-superclass class))))
                     (+ size-of-super-classes 
                        (mod size-of-super-classes +struct-alignmen+)))
     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)))
    (call-next-method))

  
  (defmethod validate-superclass ((class proxy-class) (super standard-class))
    (subtypep (class-name super) 'proxy))
  
  (defmethod proxy-instance-size (class)
    (declare (ignore class))
    0)

  (defmethod proxy-instance-size ((class-name symbol))
    (proxy-instance-size (find-class class-name)))
)
  
(defmethod alien-type ((class proxy-class) &rest args)
  (declare (ignore class args))
  (alien-type 'pointer))

(defmethod size-of ((class proxy-class) &rest args)
  (declare (ignore class args))
  (size-of 'pointer))

(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))
  `(proxy-location ,instance))

(defmethod to-alien-function ((class proxy-class) &rest args)
  (declare (ignore class args))
  #'proxy-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) (proxy-location ,instance)))

(defmethod copy-to-alien-function ((class proxy-class) &rest args)
  (declare (ignore args))
  #'(lambda (instance)
      (reference-foreign class (proxy-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 (proxy-location instance)))))

(defmethod reader-function ((class proxy-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))))))

(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)
  (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))


;;;; Superclasses for wrapping of C structures

(defclass struct (proxy)
  ()
  (:metaclass proxy-class))

(defmethod initialize-instance ((struct struct) &rest initargs)
  (declare (ignore initargs))
  (unless (slot-boundp struct 'location)
    (let ((size (proxy-instance-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))


;;;; Metaclasses used for subclasses of struct

(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)))

(defmethod unreference-foreign ((class struct-class) location)
  (deallocate-memory location))


(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)


;;; Pseudo type for structs which are inlined in other objects

(defmethod size-of ((type (eql 'inlined)) &rest args)
  (declare (ignore type))
  (proxy-instance-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 destroy-function ((type (eql 'inlined)) &rest args)
  (declare (ignore args))
  #'(lambda (location &optional (offset 0))
      (declare (ignore location offset))))

(export 'inlined)