+++ /dev/null
-1) GBoxed - это структуры, у которых нет идентичности
-2) При передаче ссылок, ссылки всегда имеют ограниченное время действия
-3) Структуры могут быть открытыми и закрытыми (opaque)
-
-Основной критерий: лисповский код не должен заботиться о владении структурами. Идентичности нет.
-
-Следствия:
-1) Все GBoxed, созданные в лиспе, удаляются только лиспом (при необходимости делается копия)
-2) Если foreign-функции возвращают GBoxed, то им владеет лисп (при необходимости делается копия)
-3) В callback'и возможна передача по ссылке (в том случае, если не знаем, как присвоить значение исходной структуре);
-в этом случае после выхода из callback'а лисповский прокси помечается как невалидный и операции с ним приводят к исключению
-
-Для реализации надо, чтобы CFFI позволяло совершать действия по очистке в конце callback'а.
-
-Код:
-
-(defclass g-boxed-type ()
- ((g-type-designator :initarg :g-type
- :initform ":G-TYPE must be specified"
- :accessor g-boxed-type-type)))
-
-;;Some terminology:
-;; * native structure - a C structure in foreign memory that
-;; has the data and is expected to be passed/received by foreign functions
-;; * proxy - a Lisp object (class or a structure) that is
-;; equivalent to native structure (has the same data in it). Its lifetime is indefinite
-;; and it is not affected by foreign code.
-;; A proxy may (but not required to) contain pointer to its own copy of a
-;; native structure.
-;; * reference proxy - a proxy that is whose lifetime is equal to a duration
-;; of a callback. Reference proxies can only be used during a callback that created them.
-
-;(defgeneric create-proxy (type)
-; "Creates a new proxy of a specified TYPE.")
-
-(defgeneric create-proxy-for-native (type native-ptr)
- (:documentation "Creates a proxy that is initialized by data contained in native
-structured pointed to by NATIVE-PTR.
-
-Created proxy should not be linked to NATIVE-PTR and should have
-indefinite lifetime (until garbage collector collects it). Specifically,
-if proxy need a pointer to native structure, it should make a copy of
-a structure.
-
-If proxy requires finalization, finalizers should be added."))
-
-(defgeneric create-temporary-native (type proxy)
- (:documentation "Creates a native structure (or passes a pointer to copy contained in PROXY)
-that contains the same data that the PROXY contains and returns a pointer to it.
-
-This call is always paired by call to FREE-TEMPORARY-NATIVE and calls may be nested."))
-
-(defgeneric free-temporary-native (type proxy native-ptr)
- (:documentation "Frees the native structure that was previously created
-by CREATE-TEMPORARY-NATIVE for the same PROXY.
-
-Also reads data from native structure pointer to by NATIVE-PTR
-and sets the PROXY to contain the same data.
-
-This call is always paired by call to CREATE-TEMPORARY-NATIVE and calls may be nested."))
-
-(defgeneric create-reference-proxy (type native-ptr)
- (:documentation "Creates a reference proxy for a native structure pointed to by NATIVE-PTR.
-
-Reference proxy's lifetime is bound to duration of a callback. When the
-callback returns the reference proxy is declared invalid and operations on it are errors.
-
-This call is always paired by call to FREE-REFERENCE-PROXY and calls will not nest."))
-
-(defgeneric free-reference-proxy (type proxy native-ptr)
- (:documentation "Frees a reference proxy PROXY previously created by call to
-CREATE-REFERENCE-PROXY. This call should ensure that all changes on PROXY are
-reflected in native structure pointed to by NATIVE-PTR.
-
-After a call to FREE-REFERENCE-PROXY, PROXY is declared invalid and using it is an error,
-operations on it should signal erros.
-
-This call is always paired by call to CREATE-REFERENCE-PROXY."))
-
-(define-foreign-type g-boxed-foreign ()
- ((g-type :initarg :g-type
- :initform (error ":G-TYPE must be specified")
- :reader g-boxed-foreign-g-type)
- (pass-type :initarg :pass-type
- :reader g-boxed-foreign-g-type
- :type (member :callback :normal)
- :initform :normal))
- (:actual-type :pointer))
-
-(defun g-boxed-foreign->boxed-type (type)
- nil)
-
-(defmethod translate-to-foreign (proxy (type g-boxed-foreign))
- (let* ((boxed-type (g-boxed-foreign->boxed-type type))
- (native-ptr (create-temporary-native boxed-type proxy)))
- (values native-ptr proxy)))
-
-(defmethod free-translated-object (native-ptr (type g-boxed-foreign) proxy)
- (let ((boxed-type (g-boxed-foreign->boxed-type type)))
- (free-temporary-native boxed-type proxy native-ptr)))
-
-(defmethod translate-from-foreign (native-ptr (type g-boxed-foreign))
- (let ((boxed-type (g-boxed-foreign->boxed-type type)))
- (ecase )
- (create-proxy-for-native boxed-type native-ptr)))
-
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