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3rdparties/software/cffi_0.21.0/src/structures.lisp (6764 bytes)

 ;;;; -*- Mode: lisp; indent-tabs-mode: nil -*-
 ;;;
 ;;; structures.lisp --- Methods for translating foreign structures.
 ;;;
 ;;; Copyright (C) 2011, Liam M. Healy  <lhealy@common-lisp.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.
 ;;;
 
 (in-package #:cffi)
 
 ;;; Definitions for conversion of foreign structures.
 
 (defmethod translate-into-foreign-memory ((object list)
                                           (type foreign-struct-type)
                                           p)
   (unless (bare-struct-type-p type)
     (loop for (name value) on object by #'cddr
           do (setf (foreign-slot-value p (unparse-type type) name)
                    (let ((slot (gethash name (structure-slots type))))
                      (convert-to-foreign value (slot-type slot)))))))
 
 (defmethod translate-to-foreign (value (type foreign-struct-type))
   (let ((ptr (foreign-alloc type)))
     (translate-into-foreign-memory value type ptr)
     ptr))
 
 (defmethod translate-from-foreign (p (type foreign-struct-type))
   ;; Iterate over slots, make plist
   (if (bare-struct-type-p type)
       p
       (let ((plist (list)))
         (loop for slot being the hash-value of (structure-slots type)
               for name = (slot-name slot)
               do (setf (getf plist name)
                        (foreign-struct-slot-value p slot)))
         plist)))
 
 (defmethod free-translated-object (ptr (type foreign-struct-type) freep)
   (unless (bare-struct-type-p type)
     ;; Look for any pointer slots and free them first
     (loop for slot being the hash-value of (structure-slots type)
           when (and (listp (slot-type slot)) (eq (first (slot-type slot)) :pointer))
             do
                ;; Free if the pointer is to a specific type, not generic :pointer
                (free-translated-object
                 (foreign-slot-value ptr type (slot-name slot))
                 (rest (slot-type slot))
                 freep))
     (foreign-free ptr)))
 
 (defmacro define-translation-method ((object type method) &body body)
   "Define a translation method for the foreign structure type; 'method is one of :into, :from, or :to, meaning relation to foreign memory.  If :into, the variable 'pointer is the foreign pointer.  Note: type must be defined and loaded before this macro is expanded, and just the bare name (without :struct) should be specified."
   (let ((tclass (class-name (class-of (cffi::parse-type `(:struct ,type))))))
     (when (eq tclass 'foreign-struct-type)
       (error "Won't replace existing translation method for foreign-struct-type"))
     `(defmethod
          ,(case method
             (:into 'translate-into-foreign-memory)
             (:from 'translate-from-foreign)
             (:to 'translate-to-foreign))
        ;; Arguments to the method
        (,object
         (type ,tclass)
         ,@(when (eq method :into) '(pointer))) ; is intentional variable capture a good idea?
        ;; The body
        (declare (ignorable type)) ; I can't think of a reason why you'd want to use this
        ,@body)))
 
 (defmacro translation-forms-for-class (class type-class)
   "Make forms for translation of foreign structures to and from a standard class.  The class slots are assumed to have the same name as the foreign structure."
   ;; Possible improvement: optional argument to map structure slot names to/from class slot names.
   `(progn
      (defmethod translate-from-foreign (pointer (type ,type-class))
        ;; Make the instance from the plist
        (apply 'make-instance ',class (call-next-method)))
      (defmethod translate-into-foreign-memory ((object ,class) (type ,type-class) pointer)
        (call-next-method
         ;; Translate into a plist and call the general method
         (loop for slot being the hash-value of (structure-slots type)
               for name = (slot-name slot)
               append (list slot-name (slot-value object slot-name)))
         type
         pointer))))
 
 ;;; For a class already defined and loaded, and a defcstruct already defined, use
 ;;; (translation-forms-for-class class type-class)
 ;;; to connnect the two.  It would be nice to have a macro to do all three simultaneously.
 ;;; (defmacro define-foreign-structure (class ))
 
 #|
 (defmacro define-structure-conversion
     (value-symbol type lisp-class slot-names to-form from-form &optional (struct-name type))
   "Define the functions necessary to convert to and from a foreign structure.  The to-form sets each of the foreign slots in succession, assume the foreign object exists.  The from-form creates the Lisp object, making it with the correct value by reference to foreign slots."
   `(flet ((map-slots (fn val)
             (maphash
              (lambda (name slot-struct)
                (funcall fn (foreign-slot-value val ',type name) (slot-type slot-struct)))
              (slots (follow-typedefs (parse-type ',type))))))
      ;; Convert this to a separate function so it doesn't have to be recomputed on the fly each time.
      (defmethod translate-to-foreign ((,value-symbol ,lisp-class) (type ,type))
        (let ((p (foreign-alloc ',struct-name)))
          ;;(map-slots #'translate-to-foreign ,value-symbol) ; recursive translation of slots
          (with-foreign-slots (,slot-names p ,struct-name)
            ,to-form)
          (values p t))) ; second value is passed to FREE-TRANSLATED-OBJECT
      (defmethod free-translated-object (,value-symbol (p ,type) freep)
        (when freep
          ;; Is this redundant?
          (map-slots #'free-translated-object value) ; recursively free slots
          (foreign-free ,value-symbol)))
      (defmethod translate-from-foreign (,value-symbol (type ,type))
        (with-foreign-slots (,slot-names ,value-symbol ,struct-name)
          ,from-form))))
 |#