:direct-superclasses supers
:direct-slots slots
:definition-source `((defclass ,name)
- ,*load-truename*)
+ ,*load-pathname*)
other)))
;; Defclass of a class with a forward-referenced superclass does not
;; have a wrapper. RES is the incomplete PCL class. The Lisp class
;;; This is called by :after shared-initialize whenever a class is initialized
;;; or reinitialized. The class may or may not be finalized.
(defun update-class (class finalizep)
+ ;; Comment from Gerd Moellmann:
+ ;;
+ ;; Note that we can't simply delay the finalization when CLASS has
+ ;; no forward referenced superclasses because that causes bootstrap
+ ;; problems.
+ (when (and (not finalizep)
+ (not (class-finalized-p class))
+ (not (class-has-a-forward-referenced-superclass-p class)))
+ (finalize-inheritance class)
+ (return-from update-class))
(when (or finalizep (class-finalized-p class)
(not (class-has-a-forward-referenced-superclass-p class)))
(update-cpl class (compute-class-precedence-list class))
+ ;; This invocation of UPDATE-SLOTS, in practice, finalizes the
+ ;; class. The hoops above are to ensure that FINALIZE-INHERITANCE
+ ;; is called at finalization, so that MOP programmers can hook
+ ;; into the system as described in "Class Finalization Protocol"
+ ;; (section 5.5.2 of AMOP).
(update-slots class (compute-slots class))
(update-gfs-of-class class)
(update-inits class (compute-default-initargs class))
(or (eq new-super-meta-class *the-class-std-class*)
(eq (class-of class) new-super-meta-class))))
\f
+;;; What this does depends on which of the four possible values of
+;;; LAYOUT-INVALID the PCL wrapper has; the simplest case is when it
+;;; is (:FLUSH <wrapper>) or (:OBSOLETE <wrapper>), when there is
+;;; nothing to do, as the new wrapper has already been created. If
+;;; LAYOUT-INVALID returns NIL, then we invalidate it (setting it to
+;;; (:FLUSH <wrapper>); UPDATE-SLOTS later gets to choose whether or
+;;; not to "upgrade" this to (:OBSOLETE <wrapper>).
+;;;
+;;; This leaves the case where LAYOUT-INVALID returns T, which happens
+;;; when REGISTER-LAYOUT has invalidated a superclass of CLASS (which
+;;; invalidated all the subclasses in SB-KERNEL land). Again, here we
+;;; must flush the caches and allow UPDATE-SLOTS to decide whether to
+;;; obsolete the wrapper.
+;;;
+;;; FIXME: either here or in INVALID-WRAPPER-P looks like a good place
+;;; for (AVER (NOT (EQ (SB-KERNEL:LAYOUT-INVALID OWRAPPER)
+;;; :UNINITIALIZED)))
+;;;
+;;; Thanks to Gerd Moellmann for the explanation. -- CSR, 2002-10-29
(defun force-cache-flushes (class)
(let* ((owrapper (class-wrapper class)))
- ;; We only need to do something if the state is still T. If the
- ;; state isn't T, it will be FLUSH or OBSOLETE, and both of those
- ;; will already be doing what we want. In particular, we must be
- ;; sure we never change an OBSOLETE into a FLUSH since OBSOLETE
- ;; means do what FLUSH does and then some.
- (unless (invalid-wrapper-p owrapper)
+ ;; We only need to do something if the wrapper is still valid. If
+ ;; the wrapper isn't valid, state will be FLUSH or OBSOLETE, and
+ ;; both of those will already be doing what we want. In
+ ;; particular, we must be sure we never change an OBSOLETE into a
+ ;; FLUSH since OBSOLETE means do what FLUSH does and then some.
+ (when (or (not (invalid-wrapper-p owrapper))
+ ;; KLUDGE: despite the observations above, this remains
+ ;; a violation of locality or what might be considered
+ ;; good style. There has to be a better way! -- CSR,
+ ;; 2002-10-29
+ (eq (sb-kernel:layout-invalid owrapper) t))
(let ((nwrapper (make-wrapper (wrapper-no-of-instance-slots owrapper)
class)))
(setf (wrapper-instance-slots-layout nwrapper)
(or (eq s *the-class-t*)
(eq s *the-class-stream*)))
\f
+;;; Some necessary methods for FORWARD-REFERENCED-CLASS
+(defmethod class-direct-slots ((class forward-referenced-class)) ())
+(defmethod class-direct-default-initargs ((class forward-referenced-class)) ())
+(macrolet ((def (method)
+ `(defmethod ,method ((class forward-referenced-class))
+ (error "~@<~I~S was called on a forward referenced class:~2I~_~S~:>"
+ ',method class))))
+ (def class-default-initargs)
+ (def class-precedence-list)
+ (def class-slots))
+
(defmethod validate-superclass ((c slot-class)
(f forward-referenced-class))
t)