I am working on cl-gobject-introspection (https://github.com/andy128k/cl-gobject-introspection), a common lisp gobject introspection binding. I am trying to use extended foreign type system of CFFI to implement foreign memory operations. I have some questions about that.
I need to manipulate foreign array. I tried to define an extended foreign array type because there is some features that is lacking in foreign-array-type. I can access/assign element of foreign array with cffi:mem-ref and setf. But I don't know how to free element of foreign array (the element type can be aggregated).
Then I checked foreign-array-type implementation of CFFI, and found there appears no way to free translated element of array too. For example:
(defvar *string-array* (cffi:convert-to-foreign #("a" "b" "c") '(:array :string 3))) (cffi:free-foreign-object *string-array* '(:array :string 3) t)
The foreign memory corresponding to string "a", "b" and "c" is not freed if my understanding were correct.
I think if there is something like cffi:mem-free like cffi:mem-ref, may be this can be resolved. It can be something like.
(defun mem-free (ptr type param &optional (offset 0)) (let* ((parsed-type (parse-type type)) (ctype (canonicalize parsed-type))) (if (aggregatep parsed-type) (free-translated-object (inc-pointer ptr offset) parsed-type param) (free-translated-object (%mem-ref ptr ctype offset) parsed-type param))))
I think you guys may have better idea about how to resolve the question.
Best Regards, Huang, Ying