;; Common Lisp bindings for GTK+ v2.0
;; Copyright (C) 2000 Espen S. Johnsen <esj@stud.cs.uit.no>
;;
;; 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.
;;
;; 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.
;;
;; 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

;; $Id: proxy.lisp,v 1.14 2004-11-19 13:02:51 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)
     (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)
     (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))))

  

(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)))

(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)))


(defmethod initialize-internal-slot-functions ((slotd effective-virtual-slot-definition))
  (with-slots (getter setter boundp) slotd
    (unless (slot-boundp slotd 'reader-function)
      (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)
      (setf 
       (slot-value slotd 'writer-function)
       (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)))
	 (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)))))))
  (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 (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))
    (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)
  (setf
   (gethash (system:sap-int (proxy-location instance)) *instance-cache*)
   (ext:make-weak-pointer instance)))

(defun find-cached-instance (location)
  (let ((ref (gethash (system:sap-int location) *instance-cache*)))
    (when ref
      (ext:weak-pointer-value ref))))

(defun instance-cached-p (location)
  (gethash (system:sap-int location) *instance-cache*))

(defun remove-cached-instance (location)
  (remhash (system:sap-int location) *instance-cache*))

;; For debuging
(defun cached-instances ()
  (let ((instances ()))
    (maphash #'(lambda (location ref)
		 (declare (ignore location))
		 (push (ext:weak-pointer-value ref) instances))
	     *instance-cache*)
    instances))
			


;;;; Proxy for alien instances

(defclass proxy ()
  ((location :reader proxy-location :type system-area-pointer)))

(defgeneric initialize-proxy (object &rest initargs))
(defgeneric instance-finalizer (object))
(defgeneric reference-foreign (class location))
(defgeneric unreference-foreign (class 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)))))

(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)))))


(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 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

(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
				&rest initargs &key size)
    (declare (ignore initargs))
    (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))
      (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 'reader-function)
	  (let ((reader (reader-function type)))
	    (setf 
	     (slot-value slotd 'reader-function)
	     #'(lambda (object)
		 (funcall reader (proxy-location object) offset)))))

	(unless (slot-boundp slotd 'writer-function)
	  (let ((writer (writer-function type))
		(destroy (destroy-function type)))
	    (setf 
	     (slot-value slotd 'writer-function)
	     #'(lambda (value object)
		 (let ((location (proxy-location object)))
		   (funcall destroy location offset) ; destroy old value
		   (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))
  

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

  (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)))
    (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 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 class 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))))


(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 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)