src/pcl/std-class.lisp

   1 ;;;; This software is part of the SBCL system. See the README file for
   2 ;;;; more information.
   3
   4 ;;;; This software is derived from software originally released by Xerox
   5 ;;;; Corporation. Copyright and release statements follow. Later modifications
   6 ;;;; to the software are in the public domain and are provided with
   7 ;;;; absolutely no warranty. See the COPYING and CREDITS files for more
   8 ;;;; information.
   9
  10 ;;;; copyright information from original PCL sources:
  11 ;;;;
  12 ;;;; Copyright (c) 1985, 1986, 1987, 1988, 1989, 1990 Xerox Corporation.
  13 ;;;; All rights reserved.
  14 ;;;;
  15 ;;;; Use and copying of this software and preparation of derivative works based
  16 ;;;; upon this software are permitted. Any distribution of this software or
  17 ;;;; derivative works must comply with all applicable United States export
  18 ;;;; control laws.
  19 ;;;;
  20 ;;;; This software is made available AS IS, and Xerox Corporation makes no
  21 ;;;; warranty about the software, its performance or its conformity to any
  22 ;;;; specification.
  23
  24 (in-package "SB-PCL")
  25 \f
  26 (defmethod slot-accessor-function ((slotd effective-slot-definition) type)
  27   (ecase type
  28     (reader (slot-definition-reader-function slotd))
  29     (writer (slot-definition-writer-function slotd))
  30     (boundp (slot-definition-boundp-function slotd))))
  31
  32 (defmethod (setf slot-accessor-function) (function
  33                                           (slotd effective-slot-definition)
  34                                           type)
  35   (ecase type
  36     (reader (setf (slot-definition-reader-function slotd) function))
  37     (writer (setf (slot-definition-writer-function slotd) function))
  38     (boundp (setf (slot-definition-boundp-function slotd) function))))
  39
  40 (defconstant +slotd-reader-function-std-p+ 1)
  41 (defconstant +slotd-writer-function-std-p+ 2)
  42 (defconstant +slotd-boundp-function-std-p+ 4)
  43 (defconstant +slotd-all-function-std-p+ 7)
  44
  45 (defmethod slot-accessor-std-p ((slotd effective-slot-definition) type)
  46   (let ((flags (slot-value slotd 'accessor-flags)))
  47     (declare (type fixnum flags))
  48     (if (eq type 'all)
  49         (eql +slotd-all-function-std-p+ flags)
  50         (let ((mask (ecase type
  51                       (reader +slotd-reader-function-std-p+)
  52                       (writer +slotd-writer-function-std-p+)
  53                       (boundp +slotd-boundp-function-std-p+))))
  54           (declare (type fixnum mask))
  55           (not (zerop (the fixnum (logand mask flags))))))))
  56
  57 (defmethod (setf slot-accessor-std-p) (value
  58                                        (slotd effective-slot-definition)
  59                                        type)
  60   (let ((mask (ecase type
  61                 (reader +slotd-reader-function-std-p+)
  62                 (writer +slotd-writer-function-std-p+)
  63                 (boundp +slotd-boundp-function-std-p+)))
  64         (flags (slot-value slotd 'accessor-flags)))
  65     (declare (type fixnum mask flags))
  66     (setf (slot-value slotd 'accessor-flags)
  67           (if value
  68               (the fixnum (logior mask flags))
  69               (the fixnum (logand (the fixnum (lognot mask)) flags)))))
  70   value)
  71
  72 (defmethod initialize-internal-slot-functions ((slotd
  73                                                 effective-slot-definition))
  74   (let* ((name (slot-value slotd 'name))
  75          (class (slot-value slotd '%class)))
  76     (dolist (type '(reader writer boundp))
  77       (let* ((gf-name (ecase type
  78                               (reader 'slot-value-using-class)
  79                               (writer '(setf slot-value-using-class))
  80                               (boundp 'slot-boundp-using-class)))
  81              (gf (gdefinition gf-name)))
  82         (compute-slot-accessor-info slotd type gf)))))
  83
  84 ;;; CMUCL (Gerd PCL 2003-04-25) comment:
  85 ;;;
  86 ;;; Compute an effective method for SLOT-VALUE-USING-CLASS, (SETF
  87 ;;; SLOT-VALUE-USING-CLASS) or SLOT-BOUNDP-USING-CLASS for reading/
  88 ;;; writing/testing effective slot SLOTD.
  89 ;;;
  90 ;;; TYPE is one of the symbols READER, WRITER or BOUNDP, depending on
  91 ;;; GF.  Store the effective method in the effective slot definition
  92 ;;; object itself; these GFs have special dispatch functions calling
  93 ;;; effective methods directly retrieved from effective slot
  94 ;;; definition objects, as an optimization.
  95 ;;;
  96 ;;; FIXME: Change the function name to COMPUTE-SVUC-SLOTD-FUNCTION,
  97 ;;; or some such.
  98 (defmethod compute-slot-accessor-info ((slotd effective-slot-definition)
  99                                        type gf)
 100   (let* ((name (slot-value slotd 'name))
 101          (class (slot-value slotd '%class))
 102          (old-slotd (find-slot-definition class name))
 103          (old-std-p (and old-slotd (slot-accessor-std-p old-slotd 'all))))
 104     (multiple-value-bind (function std-p)
 105         (if (eq *boot-state* 'complete)
 106             (get-accessor-method-function gf type class slotd)
 107             (get-optimized-std-accessor-method-function class slotd type))
 108       (setf (slot-accessor-std-p slotd type) std-p)
 109       (setf (slot-accessor-function slotd type) function))
 110     (when (and old-slotd (not (eq old-std-p (slot-accessor-std-p slotd 'all))))
 111       (push (cons class name) *pv-table-cache-update-info*))))
 112
 113 (defmethod slot-definition-allocation ((slotd structure-slot-definition))
 114   :instance)
 115 \f
 116 ;;;; various class accessors that are a little more complicated than can be
 117 ;;;; done with automatically generated reader methods
 118
 119 (defmethod class-prototype :before (class)
 120   (unless (class-finalized-p class)
 121     (error "~@<~S is not finalized.~:@>" class)))
 122
 123 ;;; KLUDGE: For some reason factoring the common body into a function
 124 ;;; breaks PCL bootstrapping, so just generate it with a macrolet for
 125 ;;; all.
 126 (macrolet ((def (class)
 127              `(defmethod class-prototype ((class ,class))
 128                 (with-slots (prototype) class
 129                   (or prototype
 130                       (setf prototype (allocate-instance class)))))))
 131   (def std-class)
 132   (def condition-class)
 133   (def structure-class))
 134
 135 (defmethod class-direct-default-initargs ((class slot-class))
 136   (plist-value class 'direct-default-initargs))
 137
 138 (defmethod class-default-initargs ((class slot-class))
 139   (plist-value class 'default-initargs))
 140
 141 (defmethod class-slot-cells ((class std-class))
 142   (plist-value class 'class-slot-cells))
 143 (defmethod (setf class-slot-cells) (new-value (class std-class))
 144   (setf (plist-value class 'class-slot-cells) new-value))
 145 \f
 146 ;;;; class accessors that are even a little bit more complicated than those
 147 ;;;; above. These have a protocol for updating them, we must implement that
 148 ;;;; protocol.
 149
 150 ;;; Maintaining the direct subclasses backpointers. The update methods are
 151 ;;; here, the values are read by an automatically generated reader method.
 152 (defmethod add-direct-subclass ((class class) (subclass class))
 153   (with-slots (direct-subclasses) class
 154     (pushnew subclass direct-subclasses)
 155     subclass))
 156 (defmethod remove-direct-subclass ((class class) (subclass class))
 157   (with-slots (direct-subclasses) class
 158     (setq direct-subclasses (remove subclass direct-subclasses))
 159     subclass))
 160
 161 ;;; Maintaining the direct-methods and direct-generic-functions backpointers.
 162 ;;;
 163 ;;; There are four generic functions involved, each has one method for the
 164 ;;; class case and another method for the damned EQL specializers. All of
 165 ;;; these are specified methods and appear in their specified place in the
 166 ;;; class graph.
 167 ;;;
 168 ;;;   ADD-DIRECT-METHOD
 169 ;;;   REMOVE-DIRECT-METHOD
 170 ;;;   SPECIALIZER-DIRECT-METHODS
 171 ;;;   SPECIALIZER-DIRECT-GENERIC-FUNCTIONS
 172 ;;;
 173 ;;; In each case, we maintain one value which is a cons. The car is the list
 174 ;;; methods. The cdr is a list of the generic functions. The cdr is always
 175 ;;; computed lazily.
 176
 177 ;;; This needs to be used recursively, in case a non-trivial user
 178 ;;; defined ADD/REMOVE-DIRECT-METHOD method ends up calling another
 179 ;;; function using the same lock.
 180 (defvar *specializer-lock* (sb-thread::make-spinlock :name "Specializer lock"))
 181
 182 (defmethod add-direct-method :around ((specializer specializer) method)
 183   ;; All the actions done under this lock are done in an order
 184   ;; that is safe to unwind at any point.
 185   (sb-thread::with-recursive-spinlock (*specializer-lock*)
 186     (call-next-method)))
 187
 188 (defmethod remove-direct-method :around ((specializer specializer) method)
 189   ;; All the actions done under this lock are done in an order
 190   ;; that is safe to unwind at any point.
 191   (sb-thread::with-recursive-spinlock (*specializer-lock*)
 192     (call-next-method)))
 193
 194 (defmethod add-direct-method ((specializer class) (method method))
 195   (let ((cell (slot-value specializer 'direct-methods)))
 196     ;; We need to first smash the CDR, because a parallel read may
 197     ;; be in progress, and because if an interrupt catches us we
 198     ;; need to have a consistent state.
 199     (setf (cdr cell) ()
 200           (car cell) (adjoin method (car cell))))
 201   method)
 202
 203 (defmethod remove-direct-method ((specializer class) (method method))
 204   (let ((cell (slot-value specializer 'direct-methods)))
 205     ;; We need to first smash the CDR, because a parallel read may
 206     ;; be in progress, and because if an interrupt catches us we
 207     ;; need to have a consistent state.
 208     (setf (cdr cell) ()
 209           (car cell) (remove method (car cell))))
 210   method)
 211
 212 (defmethod specializer-direct-methods ((specializer class))
 213   (with-slots (direct-methods) specializer
 214     (car direct-methods)))
 215
 216 (defmethod specializer-direct-generic-functions ((specializer class))
 217   (let ((cell (slot-value specializer 'direct-methods)))
 218     ;; If an ADD/REMOVE-METHOD is in progress, no matter: either
 219     ;; we behave as if we got just first or just after -- it's just
 220     ;; for update that we need to lock.
 221     (or (cdr cell)
 222         (sb-thread::with-spinlock (*specializer-lock*)
 223           (setf (cdr cell)
 224                 (let (collect)
 225                   (dolist (m (car cell))
 226                     ;; the old PCL code used COLLECTING-ONCE which used
 227                     ;; #'EQ to check for newness
 228                     (pushnew (method-generic-function m) collect :test #'eq))
 229                   (nreverse collect)))))))
 230 \f
 231 ;;; This hash table is used to store the direct methods and direct generic
 232 ;;; functions of EQL specializers. Each value in the table is the cons.
 233 (defvar *eql-specializer-methods* (make-hash-table :test 'eql))
 234 (defvar *class-eq-specializer-methods* (make-hash-table :test 'eq))
 235
 236 (defmethod specializer-method-table ((specializer eql-specializer))
 237   *eql-specializer-methods*)
 238
 239 (defmethod specializer-method-table ((specializer class-eq-specializer))
 240   *class-eq-specializer-methods*)
 241
 242 (defmethod add-direct-method ((specializer specializer-with-object)
 243                               (method method))
 244   (let* ((object (specializer-object specializer))
 245          (table (specializer-method-table specializer))
 246          (entry (gethash object table)))
 247     ;; This table is shared between multiple specializers, but
 248     ;; no worries as (at least for the time being) our hash-tables
 249     ;; are thread safe.
 250     (unless entry
 251       (setf entry
 252             (setf (gethash object table) (cons nil nil))))
 253     ;; We need to first smash the CDR, because a parallel read may
 254     ;; be in progress, and because if an interrupt catches us we
 255     ;; need to have a consistent state.
 256     (setf (cdr entry) ()
 257           (car entry) (adjoin method (car entry)))
 258     method))
 259
 260 (defmethod remove-direct-method ((specializer specializer-with-object)
 261                                  (method method))
 262   (let* ((object (specializer-object specializer))
 263          (entry (gethash object (specializer-method-table specializer))))
 264     (when entry
 265       ;; We need to first smash the CDR, because a parallel read may
 266       ;; be in progress, and because if an interrupt catches us we
 267       ;; need to have a consistent state.
 268       (setf (cdr entry) ()
 269             (car entry) (remove method (car entry))))
 270     method))
 271
 272 (defmethod specializer-direct-methods ((specializer specializer-with-object))
 273   (car (gethash (specializer-object specializer)
 274                 (specializer-method-table specializer))))
 275
 276 (defmethod specializer-direct-generic-functions ((specializer
 277                                                   specializer-with-object))
 278   (let* ((object (specializer-object specializer))
 279          (entry (gethash object (specializer-method-table specializer))))
 280     (when entry
 281       (or (cdr entry)
 282           (sb-thread::with-spinlock (*specializer-lock*)
 283             (setf (cdr entry)
 284                   (let (collect)
 285                     (dolist (m (car entry))
 286                       (pushnew (method-generic-function m) collect :test #'eq))
 287                     (nreverse collect))))))))
 288
 289 (defun map-specializers (function)
 290   (map-all-classes (lambda (class)
 291                      (funcall function (class-eq-specializer class))
 292                      (funcall function class)))
 293   (maphash (lambda (object methods)
 294              (declare (ignore methods))
 295              (intern-eql-specializer object))
 296            *eql-specializer-methods*)
 297   (maphash (lambda (object specl)
 298              (declare (ignore object))
 299              (funcall function specl))
 300            *eql-specializer-table*)
 301   nil)
 302
 303 (defun map-all-generic-functions (function)
 304   (let ((all-generic-functions (make-hash-table :test 'eq)))
 305     (map-specializers (lambda (specl)
 306                         (dolist (gf (specializer-direct-generic-functions
 307                                      specl))
 308                           (unless (gethash gf all-generic-functions)
 309                             (setf (gethash gf all-generic-functions) t)
 310                             (funcall function gf))))))
 311   nil)
 312
 313 (defmethod shared-initialize :after ((specl class-eq-specializer)
 314                                      slot-names
 315                                      &key)
 316   (declare (ignore slot-names))
 317   (setf (slot-value specl '%type) `(class-eq ,(specializer-class specl))))
 318
 319 (defmethod shared-initialize :after ((specl eql-specializer) slot-names &key)
 320   (declare (ignore slot-names))
 321   (setf (slot-value specl '%type)
 322         `(eql ,(specializer-object specl)))
 323   (setf (info :type :translator specl)
 324         (constantly (make-member-type :members (list (specializer-object specl))))))
 325
 326 (defun real-load-defclass (name metaclass-name supers slots other
 327                            readers writers slot-names source-location safe-p)
 328   (with-single-package-locked-error (:symbol name "defining ~S as a class")
 329     (%compiler-defclass name readers writers slot-names)
 330     (let ((res (apply #'ensure-class name :metaclass metaclass-name
 331                       :direct-superclasses supers
 332                       :direct-slots slots
 333                       :definition-source source-location
 334                       'safe-p safe-p
 335                       other)))
 336       res)))
 337
 338 (setf (gdefinition 'load-defclass) #'real-load-defclass)
 339
 340 (defun ensure-class (name &rest args)
 341   (apply #'ensure-class-using-class
 342          (let ((class (find-class name nil)))
 343            (when (and class (eq name (class-name class)))
 344              ;; NAME is the proper name of CLASS, so redefine it
 345              class))
 346          name
 347          args))
 348
 349 (defmethod ensure-class-using-class ((class null) name &rest args &key)
 350   (multiple-value-bind (meta initargs)
 351       (frob-ensure-class-args args)
 352     (setf class (apply #'make-instance meta :name name initargs))
 353     (without-package-locks
 354       (setf (find-class name) class))
 355     (set-class-type-translation class name)
 356     class))
 357
 358 (defmethod ensure-class-using-class ((class pcl-class) name &rest args &key)
 359   (multiple-value-bind (meta initargs)
 360       (frob-ensure-class-args args)
 361     (unless (eq (class-of class) meta)
 362       (apply #'change-class class meta initargs))
 363     (apply #'reinitialize-instance class initargs)
 364     (without-package-locks
 365       (setf (find-class name) class))
 366     (set-class-type-translation class name)
 367     class))
 368
 369 (defun frob-ensure-class-args (args)
 370   (let (metaclass metaclassp reversed-plist)
 371     (flet ((frob-superclass (s)
 372              (cond
 373                ((classp s) s)
 374                ((legal-class-name-p s)
 375                 (or (find-class s nil)
 376                     (ensure-class s :metaclass 'forward-referenced-class)))
 377                (t (error "Not a class or a legal class name: ~S." s)))))
 378       (doplist (key val) args
 379         (cond ((eq key :metaclass)
 380                (unless metaclassp
 381                  (setf metaclass val metaclassp key)))
 382               (t
 383                (when (eq key :direct-superclasses)
 384                  (setf val (mapcar #'frob-superclass val)))
 385                (setf reversed-plist (list* val key reversed-plist)))))
 386       (values (cond (metaclassp
 387                      (if (classp metaclass)
 388                          metaclass
 389                          (find-class metaclass)))
 390                     (t *the-class-standard-class*))
 391               (nreverse reversed-plist)))))
 392 \f
 393 (defmethod shared-initialize :after
 394     ((class std-class) slot-names &key
 395      (direct-superclasses nil direct-superclasses-p)
 396      (direct-slots nil direct-slots-p)
 397      (direct-default-initargs nil direct-default-initargs-p))
 398   (cond (direct-superclasses-p
 399          (setq direct-superclasses
 400                (or direct-superclasses
 401                    (list (if (funcallable-standard-class-p class)
 402                              *the-class-funcallable-standard-object*
 403                              *the-class-standard-object*))))
 404          (dolist (superclass direct-superclasses)
 405            (unless (validate-superclass class superclass)
 406              (error "~@<The class ~S was specified as a ~
 407                      super-class of the class ~S, ~
 408                      but the meta-classes ~S and ~S are incompatible.  ~
 409                      Define a method for ~S to avoid this error.~@:>"
 410                      superclass class (class-of superclass) (class-of class)
 411                      'validate-superclass)))
 412          (setf (slot-value class 'direct-superclasses) direct-superclasses))
 413         (t
 414          (setq direct-superclasses (slot-value class 'direct-superclasses))))
 415   (setq direct-slots
 416         (if direct-slots-p
 417             (setf (slot-value class 'direct-slots)
 418                   (mapcar (lambda (pl) (make-direct-slotd class pl))
 419                           direct-slots))
 420             (slot-value class 'direct-slots)))
 421   (if direct-default-initargs-p
 422       (setf (plist-value class 'direct-default-initargs)
 423             direct-default-initargs)
 424       (setq direct-default-initargs
 425             (plist-value class 'direct-default-initargs)))
 426   (setf (plist-value class 'class-slot-cells)
 427         (let ((old-class-slot-cells (plist-value class 'class-slot-cells))
 428               (collect '()))
 429           (dolist (dslotd direct-slots)
 430             (when (eq :class (slot-definition-allocation dslotd))
 431               ;; see CLHS 4.3.6
 432               (let* ((name (slot-definition-name dslotd))
 433                      (old (assoc name old-class-slot-cells)))
 434                 (if (or (not old)
 435                         (eq t slot-names)
 436                         (member name slot-names))
 437                     (let* ((initfunction (slot-definition-initfunction dslotd))
 438                            (value (if initfunction
 439                                       (funcall initfunction)
 440                                       +slot-unbound+)))
 441                       (push (cons name value) collect))
 442                     (push old collect)))))
 443           (nreverse collect)))
 444   (add-direct-subclasses class direct-superclasses)
 445   (if (class-finalized-p class)
 446       ;; required by AMOP, "Reinitialization of Class Metaobjects"
 447       (finalize-inheritance class)
 448       (update-class class nil))
 449   (add-slot-accessors class direct-slots)
 450   (make-preliminary-layout class))
 451
 452 (defmethod shared-initialize :after ((class forward-referenced-class)
 453                                      slot-names &key &allow-other-keys)
 454   (declare (ignore slot-names))
 455   (make-preliminary-layout class))
 456
 457 (defvar *allow-forward-referenced-classes-in-cpl-p* nil)
 458
 459 ;;; Give CLASS a preliminary layout if it doesn't have one already, to
 460 ;;; make it known to the type system.
 461 (defun make-preliminary-layout (class)
 462   (flet ((compute-preliminary-cpl (root)
 463            (let ((*allow-forward-referenced-classes-in-cpl-p* t))
 464              (compute-class-precedence-list root))))
 465     (without-package-locks
 466      (unless (class-finalized-p class)
 467        (let ((name (class-name class)))
 468          ;; KLUDGE: This is fairly horrible.  We need to make a
 469          ;; full-fledged CLASSOID here, not just tell the compiler that
 470          ;; some class is forthcoming, because there are legitimate
 471          ;; questions one can ask of the type system, implemented in
 472          ;; terms of CLASSOIDs, involving forward-referenced classes. So.
 473          (let ((layout (make-wrapper 0 class)))
 474            (setf (slot-value class 'wrapper) layout)
 475            (let ((cpl (compute-preliminary-cpl class)))
 476              (setf (layout-inherits layout)
 477                    (order-layout-inherits
 478                     (map 'simple-vector #'class-wrapper
 479                          (reverse (rest cpl))))))
 480            (register-layout layout :invalidate t)
 481            (set-class-type-translation class (layout-classoid layout)))))
 482      (mapc #'make-preliminary-layout (class-direct-subclasses class)))))
 483
 484
 485 (defmethod shared-initialize :before ((class class) slot-names &key name)
 486   (declare (ignore slot-names name))
 487   ;; FIXME: Could this just be CLASS instead of `(CLASS ,CLASS)? If not,
 488   ;; why not? (See also similar expression in !BOOTSTRAP-INITIALIZE-CLASS.)
 489   (setf (slot-value class '%type) `(class ,class))
 490   (setf (slot-value class 'class-eq-specializer)
 491         (make-instance 'class-eq-specializer :class class)))
 492
 493 (defmethod reinitialize-instance :before ((class slot-class) &key direct-superclasses)
 494   (dolist (old-super (set-difference (class-direct-superclasses class) direct-superclasses))
 495     (remove-direct-subclass old-super class))
 496   (remove-slot-accessors    class (class-direct-slots class)))
 497
 498 (defmethod reinitialize-instance :after ((class slot-class)
 499                                          &rest initargs
 500                                          &key)
 501   (map-dependents class
 502                   (lambda (dependent)
 503                     (apply #'update-dependent class dependent initargs))))
 504
 505 (defmethod reinitialize-instance :after ((class condition-class) &key)
 506   (let* ((name (class-name class))
 507          (classoid (find-classoid name))
 508          (slots (condition-classoid-slots classoid)))
 509     ;; to balance the REMOVE-SLOT-ACCESSORS call in
 510     ;; REINITIALIZE-INSTANCE :BEFORE (SLOT-CLASS).
 511     (dolist (slot slots)
 512       (let ((slot-name (condition-slot-name slot)))
 513         (dolist (reader (condition-slot-readers slot))
 514           ;; FIXME: see comment in SHARED-INITIALIZE :AFTER
 515           ;; (CONDITION-CLASS T), below.  -- CSR, 2005-11-18
 516           (sb-kernel::install-condition-slot-reader reader name slot-name))
 517         (dolist (writer (condition-slot-writers slot))
 518           (sb-kernel::install-condition-slot-writer writer name slot-name))))))
 519
 520 (defmethod shared-initialize :after ((class condition-class) slot-names
 521                                      &key direct-slots direct-superclasses)
 522   (declare (ignore slot-names))
 523   (let ((classoid (find-classoid (class-name class))))
 524     (with-slots (wrapper %class-precedence-list cpl-available-p
 525                          prototype (direct-supers direct-superclasses))
 526         class
 527       (setf (slot-value class 'direct-slots)
 528             (mapcar (lambda (pl) (make-direct-slotd class pl))
 529                     direct-slots))
 530       (setf (slot-value class 'finalized-p) t)
 531       (setf (classoid-pcl-class classoid) class)
 532       (setq direct-supers direct-superclasses)
 533       (setq wrapper (classoid-layout classoid))
 534       (setq %class-precedence-list (compute-class-precedence-list class))
 535       (setq cpl-available-p t)
 536       (add-direct-subclasses class direct-superclasses)
 537       (let ((slots (compute-slots class)))
 538         (setf (slot-value class 'slots) slots
 539               (slot-value class 'slot-vector) (make-slot-vector slots)))))
 540   ;; Comment from Gerd's PCL, 2003-05-15:
 541   ;;
 542   ;; We don't ADD-SLOT-ACCESSORS here because we don't want to
 543   ;; override condition accessors with generic functions.  We do this
 544   ;; differently.
 545   ;;
 546   ;; ??? What does the above comment mean and why is it a good idea?
 547   ;; CMUCL (which still as of 2005-11-18 uses this code and has this
 548   ;; comment) loses slot information in its condition classes:
 549   ;; DIRECT-SLOTS is always NIL.  We have the right information, so we
 550   ;; remove slot accessors but never put them back.  I've added a
 551   ;; REINITIALIZE-INSTANCE :AFTER (CONDITION-CLASS) method, but what
 552   ;; was meant to happen?  -- CSR, 2005-11-18
 553   (update-pv-table-cache-info class))
 554
 555 (defmethod direct-slot-definition-class ((class condition-class)
 556                                          &rest initargs)
 557   (declare (ignore initargs))
 558   (find-class 'condition-direct-slot-definition))
 559
 560 (defmethod effective-slot-definition-class ((class condition-class)
 561                                             &rest initargs)
 562   (declare (ignore initargs))
 563   (find-class 'condition-effective-slot-definition))
 564
 565 (defmethod finalize-inheritance ((class condition-class))
 566   (aver (slot-value class 'finalized-p))
 567   nil)
 568
 569 (defmethod compute-effective-slot-definition
 570     ((class condition-class) slot-name dslotds)
 571   (let ((slotd (call-next-method)))
 572     (setf (slot-definition-reader-function slotd)
 573           (lambda (x)
 574             (handler-case (condition-reader-function x slot-name)
 575               ;; FIXME: FIND-SLOT-DEFAULT throws an error if the slot
 576               ;; is unbound; maybe it should be a CELL-ERROR of some
 577               ;; sort?
 578               (error () (values (slot-unbound class x slot-name))))))
 579     (setf (slot-definition-writer-function slotd)
 580           (lambda (v x)
 581             (condition-writer-function x v slot-name)))
 582     (setf (slot-definition-boundp-function slotd)
 583           (lambda (x)
 584             (multiple-value-bind (v c)
 585                 (ignore-errors (condition-reader-function x slot-name))
 586               (declare (ignore v))
 587               (null c))))
 588     slotd))
 589
 590 (defmethod compute-slots ((class condition-class))
 591   (mapcan (lambda (superclass)
 592             (mapcar (lambda (dslotd)
 593                       (compute-effective-slot-definition
 594                        class (slot-definition-name dslotd) (list dslotd)))
 595                     (class-direct-slots superclass)))
 596           (reverse (slot-value class '%class-precedence-list))))
 597
 598 (defmethod compute-slots :around ((class condition-class))
 599   (let ((eslotds (call-next-method)))
 600     (mapc #'initialize-internal-slot-functions eslotds)
 601     eslotds))
 602
 603 (defmethod shared-initialize :after
 604     ((slotd structure-slot-definition) slot-names &key
 605      (allocation :instance) allocation-class)
 606   (declare (ignore slot-names allocation-class))
 607   (unless (eq allocation :instance)
 608     (error "Structure slots must have :INSTANCE allocation.")))
 609
 610 (defun make-structure-class-defstruct-form (name direct-slots include)
 611   (let* ((conc-name (format-symbol *package* "~S structure class " name))
 612          (constructor (format-symbol *package* "~Aconstructor" conc-name))
 613          (defstruct `(defstruct (,name
 614                                  ,@(when include
 615                                          `((:include ,(class-name include))))
 616                                  (:predicate nil)
 617                                  (:conc-name ,conc-name)
 618                                  (:constructor ,constructor ())
 619                                  (:copier nil))
 620                       ,@(mapcar (lambda (slot)
 621                                   `(,(slot-definition-name slot)
 622                                     +slot-unbound+))
 623                                 direct-slots)))
 624          (reader-names (mapcar (lambda (slotd)
 625                                  (list 'slot-accessor name
 626                                        (slot-definition-name slotd)
 627                                        'reader))
 628                                direct-slots))
 629          (writer-names (mapcar (lambda (slotd)
 630                                  (list 'slot-accessor name
 631                                        (slot-definition-name slotd)
 632                                        'writer))
 633                                direct-slots))
 634          (readers-init
 635            (mapcar (lambda (slotd reader-name)
 636                      (let ((accessor
 637                              (slot-definition-defstruct-accessor-symbol
 638                               slotd)))
 639                        `(defun ,reader-name (obj)
 640                          (declare (type ,name obj))
 641                          (,accessor obj))))
 642                    direct-slots reader-names))
 643          (writers-init
 644            (mapcar (lambda (slotd writer-name)
 645                      (let ((accessor
 646                              (slot-definition-defstruct-accessor-symbol
 647                               slotd)))
 648                        `(defun ,writer-name (nv obj)
 649                          (declare (type ,name obj))
 650                          (setf (,accessor obj) nv))))
 651                    direct-slots writer-names))
 652          (defstruct-form
 653              `(progn
 654                ,defstruct
 655                ,@readers-init ,@writers-init
 656                (cons nil nil))))
 657     (values defstruct-form constructor reader-names writer-names)))
 658
 659 (defun make-defstruct-allocation-function (class)
 660   ;; FIXME: Why don't we go class->layout->info == dd
 661   (let ((dd (find-defstruct-description (class-name class))))
 662     (lambda ()
 663       (sb-kernel::%make-instance-with-layout
 664        (sb-kernel::compiler-layout-or-lose (dd-name dd))))))
 665
 666 (defmethod shared-initialize :after
 667     ((class structure-class) slot-names &key
 668      (direct-superclasses nil direct-superclasses-p)
 669      (direct-slots nil direct-slots-p)
 670      direct-default-initargs)
 671   (declare (ignore slot-names direct-default-initargs))
 672   (if direct-superclasses-p
 673       (setf (slot-value class 'direct-superclasses)
 674             (or direct-superclasses
 675                 (setq direct-superclasses
 676                       (and (not (eq (class-name class) 'structure-object))
 677                            (list *the-class-structure-object*)))))
 678       (setq direct-superclasses (slot-value class 'direct-superclasses)))
 679   (let* ((name (class-name class))
 680          (from-defclass-p (slot-value class 'from-defclass-p))
 681          (defstruct-p (or from-defclass-p (not (structure-type-p name)))))
 682     (if direct-slots-p
 683         (setf (slot-value class 'direct-slots)
 684               (setq direct-slots
 685                     (mapcar (lambda (pl)
 686                               (when defstruct-p
 687                                 (let* ((slot-name (getf pl :name))
 688                                        (accessor
 689                                         (format-symbol *package*
 690                                                        "~S structure class ~A"
 691                                                        name slot-name)))
 692                                   (setq pl (list* :defstruct-accessor-symbol
 693                                                   accessor pl))))
 694                               (make-direct-slotd class pl))
 695                             direct-slots)))
 696         (setq direct-slots (slot-value class 'direct-slots)))
 697     (if defstruct-p
 698         (let ((include (car (slot-value class 'direct-superclasses))))
 699           (multiple-value-bind (defstruct-form constructor reader-names writer-names)
 700               (make-structure-class-defstruct-form name direct-slots include)
 701             (unless (structure-type-p name) (eval defstruct-form))
 702             (mapc (lambda (dslotd reader-name writer-name)
 703                     (let* ((reader (gdefinition reader-name))
 704                            (writer (when (fboundp writer-name)
 705                                      (gdefinition writer-name))))
 706                       (setf (slot-value dslotd 'internal-reader-function)
 707                             reader)
 708                       (setf (slot-value dslotd 'internal-writer-function)
 709                             writer)))
 710                   direct-slots reader-names writer-names)
 711             (setf (slot-value class 'defstruct-form) defstruct-form)
 712             (setf (slot-value class 'defstruct-constructor) constructor)))
 713         (setf (slot-value class 'defstruct-constructor)
 714               (make-defstruct-allocation-function class)))
 715     (add-direct-subclasses class direct-superclasses)
 716     (setf (slot-value class '%class-precedence-list)
 717           (compute-class-precedence-list class))
 718     (setf (slot-value class 'cpl-available-p) t)
 719     (let ((slots (compute-slots class)))
 720       (setf (slot-value class 'slots) slots
 721             (slot-value class 'slot-vector) (make-slot-vector slots)))
 722     (let ((lclass (find-classoid (class-name class))))
 723       (setf (classoid-pcl-class lclass) class)
 724       (setf (slot-value class 'wrapper) (classoid-layout lclass)))
 725     (setf (slot-value class 'finalized-p) t)
 726     (update-pv-table-cache-info class)
 727     (add-slot-accessors class direct-slots)))
 728
 729 (defmethod direct-slot-definition-class ((class structure-class) &rest initargs)
 730   (declare (ignore initargs))
 731   (find-class 'structure-direct-slot-definition))
 732
 733 (defmethod finalize-inheritance ((class structure-class))
 734   nil) ; always finalized
 735 \f
 736 (defun add-slot-accessors (class dslotds)
 737   (fix-slot-accessors class dslotds 'add))
 738
 739 (defun remove-slot-accessors (class dslotds)
 740   (fix-slot-accessors class dslotds 'remove))
 741
 742 (defun fix-slot-accessors (class dslotds add/remove)
 743   (flet ((fix (gfspec name r/w doc)
 744            (let ((gf (cond ((eq add/remove 'add)
 745                             (or (find-generic-function gfspec nil)
 746                                 (ensure-generic-function
 747                                  gfspec :lambda-list (case r/w
 748                                                        (r '(object))
 749                                                        (w '(new-value object))))))
 750                            (t
 751                             (find-generic-function gfspec nil)))))
 752              (when gf
 753                (case r/w
 754                  (r (if (eq add/remove 'add)
 755                         (add-reader-method class gf name doc)
 756                         (remove-reader-method class gf)))
 757                  (w (if (eq add/remove 'add)
 758                         (add-writer-method class gf name doc)
 759                         (remove-writer-method class gf))))))))
 760     (dolist (dslotd dslotds)
 761       (let ((slot-name (slot-definition-name dslotd))
 762             (slot-doc (%slot-definition-documentation dslotd)))
 763         (dolist (r (slot-definition-readers dslotd))
 764           (fix r slot-name 'r slot-doc))
 765         (dolist (w (slot-definition-writers dslotd))
 766           (fix w slot-name 'w slot-doc))))))
 767 \f
 768 (defun add-direct-subclasses (class supers)
 769   (dolist (super supers)
 770     (unless (memq class (class-direct-subclasses class))
 771       (add-direct-subclass super class))))
 772
 773 (defmethod finalize-inheritance ((class std-class))
 774   (update-class class t))
 775
 776 (defmethod finalize-inheritance ((class forward-referenced-class))
 777   ;; FIXME: should we not be thinking a bit about what kinds of error
 778   ;; we're throwing?  Maybe we need a clos-error type to mix in?  Or
 779   ;; possibly a forward-referenced-class-error, though that's
 780   ;; difficult given e.g. class precedence list calculations...
 781   (error
 782    "~@<FINALIZE-INHERITANCE was called on a forward referenced class:~
 783        ~2I~_~S~:>"
 784    class))
 785
 786 \f
 787 (defun class-has-a-forward-referenced-superclass-p (class)
 788   (or (forward-referenced-class-p class)
 789       (some #'class-has-a-forward-referenced-superclass-p
 790             (class-direct-superclasses class))))
 791
 792 ;;; This is called by :after shared-initialize whenever a class is initialized
 793 ;;; or reinitialized. The class may or may not be finalized.
 794 (defun update-class (class finalizep)
 795   (without-package-locks
 796     (when (or finalizep (class-finalized-p class))
 797       (update-cpl class (compute-class-precedence-list class))
 798       ;; This invocation of UPDATE-SLOTS, in practice, finalizes the
 799       ;; class.
 800       (update-slots class (compute-slots class))
 801       (update-gfs-of-class class)
 802       (update-initargs class (compute-default-initargs class))
 803       (update-ctors 'finalize-inheritance :class class))
 804     (dolist (sub (class-direct-subclasses class))
 805       (update-class sub nil))))
 806
 807 (define-condition cpl-protocol-violation (reference-condition error)
 808   ((class :initarg :class :reader cpl-protocol-violation-class)
 809    (cpl :initarg :cpl :reader cpl-protocol-violation-cpl))
 810   (:default-initargs :references (list '(:sbcl :node "Metaobject Protocol")))
 811   (:report
 812    (lambda (c s)
 813      (format s "~@<Protocol violation: the ~S class ~S ~
 814                 ~:[has~;does not have~] the class ~S in its ~
 815                 class precedence list: ~S.~@:>"
 816              (class-name (class-of (cpl-protocol-violation-class c)))
 817              (cpl-protocol-violation-class c)
 818              (eq (class-of (cpl-protocol-violation-class c))
 819                  *the-class-funcallable-standard-class*)
 820              (find-class 'function)
 821              (cpl-protocol-violation-cpl c)))))
 822
 823 (defun update-cpl (class cpl)
 824   (when (eq (class-of class) *the-class-standard-class*)
 825     (when (find (find-class 'function) cpl)
 826       (error 'cpl-protocol-violation :class class :cpl cpl)))
 827   (when (eq (class-of class) *the-class-funcallable-standard-class*)
 828     (unless (find (find-class 'function) cpl)
 829       (error 'cpl-protocol-violation :class class :cpl cpl)))
 830   (if (class-finalized-p class)
 831       (unless (and (equal (class-precedence-list class) cpl)
 832                    (dolist (c cpl t)
 833                      (when (position :class (class-direct-slots c)
 834                                      :key #'slot-definition-allocation)
 835                        (return nil))))
 836         ;; comment from the old CMU CL sources:
 837         ;;   Need to have the cpl setup before update-lisp-class-layout
 838         ;;   is called on CMU CL.
 839         (setf (slot-value class '%class-precedence-list) cpl)
 840         (setf (slot-value class 'cpl-available-p) t)
 841         (force-cache-flushes class))
 842       (progn
 843         (setf (slot-value class '%class-precedence-list) cpl)
 844         (setf (slot-value class 'cpl-available-p) t)))
 845   (update-class-can-precede-p cpl))
 846
 847 (defun update-class-can-precede-p (cpl)
 848   (when cpl
 849     (let ((first (car cpl)))
 850       (dolist (c (cdr cpl))
 851         (pushnew c (slot-value first 'can-precede-list))))
 852     (update-class-can-precede-p (cdr cpl))))
 853
 854 (defun class-can-precede-p (class1 class2)
 855   (member class2 (class-can-precede-list class1)))
 856
 857 (defun update-slots (class eslotds)
 858   (let ((instance-slots ())
 859         (class-slots    ()))
 860     (dolist (eslotd eslotds)
 861       (let ((alloc (slot-definition-allocation eslotd)))
 862         (case alloc
 863           (:instance (push eslotd instance-slots))
 864           (:class (push eslotd class-slots)))))
 865
 866     ;; If there is a change in the shape of the instances then the
 867     ;; old class is now obsolete.
 868     (let* ((nlayout (mapcar #'slot-definition-name
 869                             (sort instance-slots #'<
 870                                   :key #'slot-definition-location)))
 871            (nslots (length nlayout))
 872            (nwrapper-class-slots (compute-class-slots class-slots))
 873            (owrapper (when (class-finalized-p class)
 874                        (class-wrapper class)))
 875            (olayout (when owrapper
 876                       (wrapper-instance-slots-layout owrapper)))
 877            (owrapper-class-slots (and owrapper (wrapper-class-slots owrapper)))
 878            (nwrapper
 879             (cond ((null owrapper)
 880                    (make-wrapper nslots class))
 881                   ((and (equal nlayout olayout)
 882                         (not
 883                          (loop for o in owrapper-class-slots
 884                                for n in nwrapper-class-slots
 885                                do (unless (eq (car o) (car n)) (return t)))))
 886                    owrapper)
 887                   (t
 888                    ;; This will initialize the new wrapper to have the
 889                    ;; same state as the old wrapper. We will then have
 890                    ;; to change that. This may seem like wasted work
 891                    ;; (and it is), but the spec requires that we call
 892                    ;; MAKE-INSTANCES-OBSOLETE.
 893                    (make-instances-obsolete class)
 894                    (class-wrapper class)))))
 895
 896       (update-lisp-class-layout class nwrapper)
 897       (setf (slot-value class 'slots) eslotds
 898             (slot-value class 'slot-vector) (make-slot-vector eslotds)
 899             (wrapper-instance-slots-layout nwrapper) nlayout
 900             (wrapper-class-slots nwrapper) nwrapper-class-slots
 901             (layout-length nwrapper) nslots
 902             (slot-value class 'wrapper) nwrapper)
 903       (do* ((slots (slot-value class 'slots) (cdr slots))
 904             (dupes nil))
 905            ((null slots)
 906             (when dupes
 907               (style-warn
 908                "~@<slot names with the same SYMBOL-NAME but ~
 909                   different SYMBOL-PACKAGE (possible package problem) ~
 910                   for class ~S:~4I~@:_~<~@{~S~^~:@_~}~:>~@:>"
 911                class dupes)))
 912         (let* ((slot (car slots))
 913                (oslots (remove (slot-definition-name slot) (cdr slots)
 914                                :test #'string/=
 915                                :key #'slot-definition-name)))
 916           (when oslots
 917             (pushnew (cons (slot-definition-name slot)
 918                            (mapcar #'slot-definition-name oslots))
 919                      dupes
 920                      :test #'string= :key #'car))))
 921       (setf (slot-value class 'finalized-p) t)
 922       (unless (eq owrapper nwrapper)
 923         (update-pv-table-cache-info class)
 924         (maybe-update-standard-class-locations class)))))
 925
 926 (defun compute-class-slots (eslotds)
 927   (let (collect)
 928     (dolist (eslotd eslotds (nreverse collect))
 929       (let ((cell (assoc (slot-definition-name eslotd)
 930                          (class-slot-cells
 931                           (slot-definition-allocation-class eslotd)))))
 932         (aver cell)
 933         (push cell collect)))))
 934
 935 (defun update-gfs-of-class (class)
 936   (when (and (class-finalized-p class)
 937              (let ((cpl (class-precedence-list class)))
 938                (or (member *the-class-slot-class* cpl)
 939                    (member *the-class-standard-effective-slot-definition*
 940                            cpl))))
 941     (let ((gf-table (make-hash-table :test 'eq)))
 942       (labels ((collect-gfs (class)
 943                  (dolist (gf (specializer-direct-generic-functions class))
 944                    (setf (gethash gf gf-table) t))
 945                  (mapc #'collect-gfs (class-direct-superclasses class))))
 946         (collect-gfs class)
 947         (maphash (lambda (gf ignore)
 948                    (declare (ignore ignore))
 949                    (update-gf-dfun class gf))
 950                  gf-table)))))
 951
 952 (defun update-initargs (class inits)
 953   (setf (plist-value class 'default-initargs) inits))
 954 \f
 955 (defmethod compute-default-initargs ((class slot-class))
 956   (let ((initargs (loop for c in (class-precedence-list class)
 957                         append (class-direct-default-initargs c))))
 958     (delete-duplicates initargs :test #'eq :key #'car :from-end t)))
 959 \f
 960 ;;;; protocols for constructing direct and effective slot definitions
 961
 962 (defmethod direct-slot-definition-class ((class std-class) &rest initargs)
 963   (declare (ignore initargs))
 964   (find-class 'standard-direct-slot-definition))
 965
 966 (defun make-direct-slotd (class initargs)
 967   (apply #'make-instance
 968          (apply #'direct-slot-definition-class class initargs)
 969          :class class
 970          initargs))
 971
 972 ;;; I (CSR) am not sure, but I believe that the particular order of
 973 ;;; slots is quite important: it is ideal to attempt to have a
 974 ;;; constant slot location for the same notional slots as much as
 975 ;;; possible, so that clever discriminating functions (ONE-INDEX et
 976 ;;; al.) have a chance of working.  The below at least walks through
 977 ;;; the slots predictably, but maybe it would be good to compute some
 978 ;;; kind of optimal slot layout by looking at locations of slots in
 979 ;;; superclasses?
 980 (defun std-compute-slots (class)
 981   ;; As specified, we must call COMPUTE-EFFECTIVE-SLOT-DEFINITION once
 982   ;; for each different slot name we find in our superclasses. Each
 983   ;; call receives the class and a list of the dslotds with that name.
 984   ;; The list is in most-specific-first order.
 985   (let ((name-dslotds-alist ()))
 986     (dolist (c (reverse (class-precedence-list class)))
 987       (dolist (slot (class-direct-slots c))
 988         (let* ((name (slot-definition-name slot))
 989                (entry (assq name name-dslotds-alist)))
 990           (if entry
 991               (push slot (cdr entry))
 992               (push (list name slot) name-dslotds-alist)))))
 993     (mapcar (lambda (direct)
 994               (compute-effective-slot-definition class
 995                                                  (car direct)
 996                                                  (cdr direct)))
 997             (nreverse name-dslotds-alist))))
 998
 999 (defmethod compute-slots ((class standard-class))
1000   (std-compute-slots class))
1001 (defmethod compute-slots ((class funcallable-standard-class))
1002   (std-compute-slots class))
1003
1004 (defun std-compute-slots-around (class eslotds)
1005   (let ((location -1))
1006     (dolist (eslotd eslotds eslotds)
1007       (setf (slot-definition-location eslotd)
1008             (case (slot-definition-allocation eslotd)
1009               (:instance
1010                (incf location))
1011               (:class
1012                (let* ((name (slot-definition-name eslotd))
1013                       (from-class
1014                        (or
1015                         (slot-definition-allocation-class eslotd)
1016                         ;; we get here if the user adds an extra slot
1017                         ;; himself...
1018                         (setf (slot-definition-allocation-class eslotd)
1019                               class)))
1020                       ;; which raises the question of what we should
1021                       ;; do if we find that said user has added a slot
1022                       ;; with the same name as another slot...
1023                       (cell (or (assq name (class-slot-cells from-class))
1024                                 (let ((c (cons name +slot-unbound+)))
1025                                   (push c (class-slot-cells from-class))
1026                                   c))))
1027                  (aver (consp cell))
1028                  (if (eq +slot-unbound+ (cdr cell))
1029                      ;; We may have inherited an initfunction
1030                      (let ((initfun (slot-definition-initfunction eslotd)))
1031                        (if initfun
1032                            (rplacd cell (funcall initfun))
1033                            cell))
1034                      cell)))))
1035       (unless (slot-definition-class eslotd)
1036         (setf (slot-definition-class eslotd) class))
1037       (initialize-internal-slot-functions eslotd))))
1038
1039 (defmethod compute-slots :around ((class standard-class))
1040   (let ((eslotds (call-next-method)))
1041     (std-compute-slots-around class eslotds)))
1042 (defmethod compute-slots :around ((class funcallable-standard-class))
1043   (let ((eslotds (call-next-method)))
1044     (std-compute-slots-around class eslotds)))
1045
1046 (defmethod compute-slots ((class structure-class))
1047   (mapcan (lambda (superclass)
1048             (mapcar (lambda (dslotd)
1049                       (compute-effective-slot-definition
1050                        class
1051                        (slot-definition-name dslotd)
1052                        (list dslotd)))
1053                     (class-direct-slots superclass)))
1054           (reverse (slot-value class '%class-precedence-list))))
1055
1056 (defmethod compute-slots :around ((class structure-class))
1057   (let ((eslotds (call-next-method)))
1058     (mapc #'initialize-internal-slot-functions eslotds)
1059     eslotds))
1060
1061 (defmethod compute-effective-slot-definition ((class slot-class) name dslotds)
1062   (declare (ignore name))
1063   (let* ((initargs (compute-effective-slot-definition-initargs class dslotds))
1064          (class (apply #'effective-slot-definition-class class initargs)))
1065     (apply #'make-instance class initargs)))
1066
1067 (defmethod effective-slot-definition-class ((class std-class) &rest initargs)
1068   (declare (ignore initargs))
1069   (find-class 'standard-effective-slot-definition))
1070
1071 (defmethod effective-slot-definition-class ((class structure-class) &rest initargs)
1072   (declare (ignore initargs))
1073   (find-class 'structure-effective-slot-definition))
1074
1075 (defmethod compute-effective-slot-definition-initargs
1076     ((class slot-class) direct-slotds)
1077   (let* ((name nil)
1078          (initfunction nil)
1079          (initform nil)
1080          (initargs nil)
1081          (allocation nil)
1082          (allocation-class nil)
1083          (type t)
1084          (type-check-function nil)
1085          (documentation nil)
1086          (documentationp nil)
1087          (namep  nil)
1088          (initp  nil)
1089          (allocp nil))
1090
1091     (dolist (slotd direct-slotds)
1092       (when slotd
1093         (unless namep
1094           (setq name (slot-definition-name slotd)
1095                 namep t))
1096         (unless initp
1097           (when (slot-definition-initfunction slotd)
1098             (setq initform (slot-definition-initform slotd)
1099                   initfunction (slot-definition-initfunction slotd)
1100                   initp t)))
1101         (unless documentationp
1102           (when (%slot-definition-documentation slotd)
1103             (setq documentation (%slot-definition-documentation slotd)
1104                   documentationp t)))
1105         (unless allocp
1106           (setq allocation (slot-definition-allocation slotd)
1107                 allocation-class (slot-definition-class slotd)
1108                 allocp t))
1109         (setq initargs (append (slot-definition-initargs slotd) initargs))
1110         (let ((fun (slot-definition-type-check-function slotd)))
1111           (when fun
1112             (setf type-check-function
1113                   (if type-check-function
1114                       (let ((old-function type-check-function))
1115                         (lambda (value)
1116                           (funcall old-function value)
1117                           (funcall fun value)))
1118                       fun))))
1119         (let ((slotd-type (slot-definition-type slotd)))
1120           (setq type (cond
1121                        ((eq type t) slotd-type)
1122                        ;; This pairwise type intersection is perhaps a
1123                        ;; little inefficient and inelegant, but it's
1124                        ;; unlikely to lie on the critical path.  Shout
1125                        ;; if I'm wrong.  -- CSR, 2005-11-24
1126                        (t (type-specifier
1127                            (specifier-type `(and ,type ,slotd-type)))))))))
1128     (list :name name
1129           :initform initform
1130           :initfunction initfunction
1131           :initargs initargs
1132           :allocation allocation
1133           :allocation-class allocation-class
1134           :type type
1135           'type-check-function type-check-function
1136           :class class
1137           :documentation documentation)))
1138
1139 (defmethod compute-effective-slot-definition-initargs :around
1140     ((class structure-class) direct-slotds)
1141   (let ((slotd (car direct-slotds)))
1142     (list* :defstruct-accessor-symbol
1143            (slot-definition-defstruct-accessor-symbol slotd)
1144            :internal-reader-function
1145            (slot-definition-internal-reader-function slotd)
1146            :internal-writer-function
1147            (slot-definition-internal-writer-function slotd)
1148            (call-next-method))))
1149 \f
1150 ;;; NOTE: For bootstrapping considerations, these can't use MAKE-INSTANCE
1151 ;;;       to make the method object. They have to use make-a-method which
1152 ;;;       is a specially bootstrapped mechanism for making standard methods.
1153 (defmethod reader-method-class ((class slot-class) direct-slot &rest initargs)
1154   (declare (ignore direct-slot initargs))
1155   (find-class 'standard-reader-method))
1156
1157 (defmethod add-reader-method ((class slot-class) generic-function slot-name slot-documentation)
1158   (add-method generic-function
1159               (make-a-method 'standard-reader-method
1160                              ()
1161                              (list (or (class-name class) 'object))
1162                              (list class)
1163                              (make-reader-method-function class slot-name)
1164                              (or slot-documentation "automatically generated reader method")
1165                              :slot-name slot-name
1166                              :object-class class
1167                              :method-class-function #'reader-method-class)))
1168
1169 (defmethod writer-method-class ((class slot-class) direct-slot &rest initargs)
1170   (declare (ignore direct-slot initargs))
1171   (find-class 'standard-writer-method))
1172
1173 (defmethod add-writer-method ((class slot-class) generic-function slot-name slot-documentation)
1174   (add-method generic-function
1175               (make-a-method 'standard-writer-method
1176                              ()
1177                              (list 'new-value (or (class-name class) 'object))
1178                              (list *the-class-t* class)
1179                              (make-writer-method-function class slot-name)
1180                              (or slot-documentation "automatically generated writer method")
1181                              :slot-name slot-name
1182                              :object-class class
1183                              :method-class-function #'writer-method-class)))
1184
1185 (defmethod add-boundp-method ((class slot-class) generic-function slot-name slot-documentation)
1186   (add-method generic-function
1187               (make-a-method (constantly (find-class 'standard-boundp-method))
1188                              class
1189                              ()
1190                              (list (or (class-name class) 'object))
1191                              (list class)
1192                              (make-boundp-method-function class slot-name)
1193                              (or slot-documentation "automatically generated boundp method")
1194                              slot-name)))
1195
1196 (defmethod remove-reader-method ((class slot-class) generic-function)
1197   (let ((method (get-method generic-function () (list class) nil)))
1198     (when method (remove-method generic-function method))))
1199
1200 (defmethod remove-writer-method ((class slot-class) generic-function)
1201   (let ((method
1202           (get-method generic-function () (list *the-class-t* class) nil)))
1203     (when method (remove-method generic-function method))))
1204
1205 (defmethod remove-boundp-method ((class slot-class) generic-function)
1206   (let ((method (get-method generic-function () (list class) nil)))
1207     (when method (remove-method generic-function method))))
1208 \f
1209 ;;; MAKE-READER-METHOD-FUNCTION and MAKE-WRITER-METHOD-FUNCTION
1210 ;;; function are NOT part of the standard protocol. They are however
1211 ;;; useful; PCL makes use of them internally and documents them for
1212 ;;; PCL users.  (FIXME: but SBCL certainly doesn't)
1213 ;;;
1214 ;;; *** This needs work to make type testing by the writer functions which
1215 ;;; *** do type testing faster. The idea would be to have one constructor
1216 ;;; *** for each possible type test.
1217 ;;;
1218 ;;; *** There is a subtle bug here which is going to have to be fixed.
1219 ;;; *** Namely, the simplistic use of the template has to be fixed. We
1220 ;;; *** have to give the OPTIMIZE-SLOT-VALUE method the user might have
1221 ;;; *** defined for this metaclass a chance to run.
1222
1223 (defmethod make-reader-method-function ((class slot-class) slot-name)
1224   (make-std-reader-method-function class slot-name))
1225
1226 (defmethod make-writer-method-function ((class slot-class) slot-name)
1227   (make-std-writer-method-function class slot-name))
1228
1229 (defmethod make-boundp-method-function ((class slot-class) slot-name)
1230   (make-std-boundp-method-function class slot-name))
1231 \f
1232 (defmethod compatible-meta-class-change-p (class proto-new-class)
1233   (eq (class-of class) (class-of proto-new-class)))
1234
1235 (defmethod validate-superclass ((class class) (superclass class))
1236   (or (eq superclass *the-class-t*)
1237       (eq (class-of class) (class-of superclass))
1238       (and (eq (class-of superclass) *the-class-standard-class*)
1239            (eq (class-of class) *the-class-funcallable-standard-class*))
1240       (and (eq (class-of superclass) *the-class-funcallable-standard-class*)
1241            (eq (class-of class) *the-class-standard-class*))))
1242 \f
1243 ;;; What this does depends on which of the four possible values of
1244 ;;; LAYOUT-INVALID the PCL wrapper has; the simplest case is when it
1245 ;;; is (:FLUSH <wrapper>) or (:OBSOLETE <wrapper>), when there is
1246 ;;; nothing to do, as the new wrapper has already been created.  If
1247 ;;; LAYOUT-INVALID returns NIL, then we invalidate it (setting it to
1248 ;;; (:FLUSH <wrapper>); UPDATE-SLOTS later gets to choose whether or
1249 ;;; not to "upgrade" this to (:OBSOLETE <wrapper>).
1250 ;;;
1251 ;;; This leaves the case where LAYOUT-INVALID returns T, which happens
1252 ;;; when REGISTER-LAYOUT has invalidated a superclass of CLASS (which
1253 ;;; invalidated all the subclasses in SB-KERNEL land).  Again, here we
1254 ;;; must flush the caches and allow UPDATE-SLOTS to decide whether to
1255 ;;; obsolete the wrapper.
1256 ;;;
1257 ;;; FIXME: either here or in INVALID-WRAPPER-P looks like a good place
1258 ;;; for (AVER (NOT (EQ (LAYOUT-INVALID OWRAPPER)
1259 ;;;                    :UNINITIALIZED)))
1260 ;;;
1261 ;;; Thanks to Gerd Moellmann for the explanation.  -- CSR, 2002-10-29
1262 (defun force-cache-flushes (class)
1263   (let* ((owrapper (class-wrapper class)))
1264     ;; We only need to do something if the wrapper is still valid. If
1265     ;; the wrapper isn't valid, state will be FLUSH or OBSOLETE, and
1266     ;; both of those will already be doing what we want. In
1267     ;; particular, we must be sure we never change an OBSOLETE into a
1268     ;; FLUSH since OBSOLETE means do what FLUSH does and then some.
1269     (when (or (not (invalid-wrapper-p owrapper))
1270               ;; KLUDGE: despite the observations above, this remains
1271               ;; a violation of locality or what might be considered
1272               ;; good style.  There has to be a better way!  -- CSR,
1273               ;; 2002-10-29
1274               (eq (layout-invalid owrapper) t))
1275       (let ((nwrapper (make-wrapper (layout-length owrapper)
1276                                     class)))
1277         (setf (wrapper-instance-slots-layout nwrapper)
1278               (wrapper-instance-slots-layout owrapper))
1279         (setf (wrapper-class-slots nwrapper)
1280               (wrapper-class-slots owrapper))
1281         (with-pcl-lock
1282           (update-lisp-class-layout class nwrapper)
1283           (setf (slot-value class 'wrapper) nwrapper)
1284           ;; Use :OBSOLETE instead of :FLUSH if any superclass has
1285           ;; been obsoleted.
1286           (if (find-if (lambda (x)
1287                          (and (consp x) (eq :obsolete (car x))))
1288                        (layout-inherits owrapper)
1289                        :key #'layout-invalid)
1290               (invalidate-wrapper owrapper :obsolete nwrapper)
1291               (invalidate-wrapper owrapper :flush nwrapper)))))))
1292
1293 (defun flush-cache-trap (owrapper nwrapper instance)
1294   (declare (ignore owrapper))
1295   (set-wrapper instance nwrapper))
1296 \f
1297 ;;; MAKE-INSTANCES-OBSOLETE can be called by user code. It will cause
1298 ;;; the next access to the instance (as defined in 88-002R) to trap
1299 ;;; through the UPDATE-INSTANCE-FOR-REDEFINED-CLASS mechanism.
1300 (defmethod make-instances-obsolete ((class std-class))
1301   (let* ((owrapper (class-wrapper class))
1302          (nwrapper (make-wrapper (layout-length owrapper)
1303                                  class)))
1304     (unless (class-finalized-p class)
1305       (if (class-has-a-forward-referenced-superclass-p class)
1306           (return-from make-instances-obsolete class)
1307           (update-cpl class (compute-class-precedence-list class))))
1308     (setf (wrapper-instance-slots-layout nwrapper)
1309           (wrapper-instance-slots-layout owrapper))
1310     (setf (wrapper-class-slots nwrapper)
1311           (wrapper-class-slots owrapper))
1312     (with-pcl-lock
1313         (update-lisp-class-layout class nwrapper)
1314       (setf (slot-value class 'wrapper) nwrapper)
1315       (invalidate-wrapper owrapper :obsolete nwrapper)
1316       class)))
1317
1318 (defmethod make-instances-obsolete ((class symbol))
1319   (make-instances-obsolete (find-class class))
1320   ;; ANSI wants the class name when called with a symbol.
1321   class)
1322
1323 ;;; OBSOLETE-INSTANCE-TRAP is the internal trap that is called when we
1324 ;;; see an obsolete instance. The times when it is called are:
1325 ;;;   - when the instance is involved in method lookup
1326 ;;;   - when attempting to access a slot of an instance
1327 ;;;
1328 ;;; It is not called by class-of, wrapper-of, or any of the low-level
1329 ;;; instance access macros.
1330 ;;;
1331 ;;; Of course these times when it is called are an internal
1332 ;;; implementation detail of PCL and are not part of the documented
1333 ;;; description of when the obsolete instance update happens. The
1334 ;;; documented description is as it appears in 88-002R.
1335 ;;;
1336 ;;; This has to return the new wrapper, so it counts on all the
1337 ;;; methods on obsolete-instance-trap-internal to return the new
1338 ;;; wrapper. It also does a little internal error checking to make
1339 ;;; sure that the traps are only happening when they should, and that
1340 ;;; the trap methods are computing appropriate new wrappers.
1341
1342 ;;; OBSOLETE-INSTANCE-TRAP might be called on structure instances
1343 ;;; after a structure is redefined. In most cases,
1344 ;;; OBSOLETE-INSTANCE-TRAP will not be able to fix the old instance,
1345 ;;; so it must signal an error. The hard part of this is that the
1346 ;;; error system and debugger might cause OBSOLETE-INSTANCE-TRAP to be
1347 ;;; called again, so in that case, we have to return some reasonable
1348 ;;; wrapper, instead.
1349
1350 (defvar *in-obsolete-instance-trap* nil)
1351 (defvar *the-wrapper-of-structure-object*
1352   (class-wrapper (find-class 'structure-object)))
1353
1354 (define-condition obsolete-structure (error)
1355   ((datum :reader obsolete-structure-datum :initarg :datum))
1356   (:report
1357    (lambda (condition stream)
1358      ;; Don't try to print the structure, since it probably won't work.
1359      (format stream
1360              "~@<obsolete structure error for a structure of type ~2I~_~S~:>"
1361              (type-of (obsolete-structure-datum condition))))))
1362
1363 (defun obsolete-instance-trap (owrapper nwrapper instance)
1364   (if (not (layout-for-std-class-p owrapper))
1365       (if *in-obsolete-instance-trap*
1366           *the-wrapper-of-structure-object*
1367            (let ((*in-obsolete-instance-trap* t))
1368              (error 'obsolete-structure :datum instance)))
1369       (let* ((class (wrapper-class* nwrapper))
1370              (copy (allocate-instance class)) ;??? allocate-instance ???
1371              (olayout (wrapper-instance-slots-layout owrapper))
1372              (nlayout (wrapper-instance-slots-layout nwrapper))
1373              (oslots (get-slots instance))
1374              (nslots (get-slots copy))
1375              (oclass-slots (wrapper-class-slots owrapper))
1376              (added ())
1377              (discarded ())
1378              (plist ()))
1379
1380         ;; local  --> local     transfer value
1381         ;; local  --> shared    discard value, discard slot
1382         ;; local  -->  --       discard slot
1383         ;; shared --> local     transfer value
1384         ;; shared --> shared    -- (cf SHARED-INITIALIZE :AFTER STD-CLASS)
1385         ;; shared -->  --       discard value
1386         ;;  --    --> local     add slot
1387         ;;  --    --> shared    --
1388
1389         ;; Go through all the old local slots.
1390         (let ((opos 0))
1391           (dolist (name olayout)
1392             (let ((npos (posq name nlayout)))
1393               (if npos
1394                   (setf (clos-slots-ref nslots npos)
1395                         (clos-slots-ref oslots opos))
1396                   (progn
1397                     (push name discarded)
1398                     (unless (eq (clos-slots-ref oslots opos) +slot-unbound+)
1399                       (setf (getf plist name) (clos-slots-ref oslots opos))))))
1400             (incf opos)))
1401
1402         ;; Go through all the old shared slots.
1403         (dolist (oclass-slot-and-val oclass-slots)
1404           (let ((name (car oclass-slot-and-val))
1405                 (val (cdr oclass-slot-and-val)))
1406             (let ((npos (posq name nlayout)))
1407               (when npos
1408                 (setf (clos-slots-ref nslots npos) val)))))
1409
1410         ;; Go through all the new local slots to compute the added slots.
1411         (dolist (nlocal nlayout)
1412           (unless (or (memq nlocal olayout)
1413                       (assq nlocal oclass-slots))
1414             (push nlocal added)))
1415
1416         (swap-wrappers-and-slots instance copy)
1417
1418         (update-instance-for-redefined-class instance
1419                                              added
1420                                              discarded
1421                                              plist)
1422         nwrapper)))
1423 \f
1424 (defun change-class-internal (instance new-class initargs)
1425   (let* ((old-class (class-of instance))
1426          (copy (allocate-instance new-class))
1427          (new-wrapper (get-wrapper copy))
1428          (old-wrapper (class-wrapper old-class))
1429          (old-layout (wrapper-instance-slots-layout old-wrapper))
1430          (new-layout (wrapper-instance-slots-layout new-wrapper))
1431          (old-slots (get-slots instance))
1432          (new-slots (get-slots copy))
1433          (old-class-slots (wrapper-class-slots old-wrapper)))
1434
1435     ;; "The values of local slots specified by both the class CTO and
1436     ;; CFROM are retained. If such a local slot was unbound, it
1437     ;; remains unbound."
1438     (let ((new-position 0))
1439       (dolist (new-slot new-layout)
1440         (let ((old-position (posq new-slot old-layout)))
1441           (when old-position
1442             (setf (clos-slots-ref new-slots new-position)
1443                   (clos-slots-ref old-slots old-position))))
1444         (incf new-position)))
1445
1446     ;; "The values of slots specified as shared in the class CFROM and
1447     ;; as local in the class CTO are retained."
1448     (dolist (slot-and-val old-class-slots)
1449       (let ((position (posq (car slot-and-val) new-layout)))
1450         (when position
1451           (setf (clos-slots-ref new-slots position) (cdr slot-and-val)))))
1452
1453     ;; Make the copy point to the old instance's storage, and make the
1454     ;; old instance point to the new storage.
1455     (swap-wrappers-and-slots instance copy)
1456
1457     (apply #'update-instance-for-different-class copy instance initargs)
1458     instance))
1459
1460 (defmethod change-class ((instance standard-object) (new-class standard-class)
1461                          &rest initargs)
1462   (unless (class-finalized-p new-class)
1463     (finalize-inheritance new-class))
1464   (let ((cpl (class-precedence-list new-class)))
1465     (dolist (class cpl)
1466       (macrolet
1467           ((frob (class-name)
1468              `(when (eq class (find-class ',class-name))
1469                (error 'metaobject-initialization-violation
1470                 :format-control "~@<Cannot ~S objects into ~S metaobjects.~@:>"
1471                 :format-arguments (list 'change-class ',class-name)
1472                 :references (list '(:amop :initialization ,class-name))))))
1473         (frob class)
1474         (frob generic-function)
1475         (frob method)
1476         (frob slot-definition))))
1477   (change-class-internal instance new-class initargs))
1478
1479 (defmethod change-class ((instance forward-referenced-class)
1480                          (new-class standard-class) &rest initargs)
1481   (let ((cpl (class-precedence-list new-class)))
1482     (dolist (class cpl
1483              (error 'metaobject-initialization-violation
1484                     :format-control
1485                     "~@<Cannot ~S ~S objects into non-~S objects.~@:>"
1486                     :format-arguments
1487                     (list 'change-class 'forward-referenced-class 'class)
1488                     :references
1489                     (list '(:amop :generic-function ensure-class-using-class)
1490                           '(:amop :initialization class))))
1491       (when (eq class (find-class 'class))
1492         (return nil))))
1493   (change-class-internal instance new-class initargs))
1494
1495 (defmethod change-class ((instance funcallable-standard-object)
1496                          (new-class funcallable-standard-class)
1497                          &rest initargs)
1498   (let ((cpl (class-precedence-list new-class)))
1499     (dolist (class cpl)
1500       (macrolet
1501           ((frob (class-name)
1502              `(when (eq class (find-class ',class-name))
1503                (error 'metaobject-initialization-violation
1504                 :format-control "~@<Cannot ~S objects into ~S metaobjects.~@:>"
1505                 :format-arguments (list 'change-class ',class-name)
1506                 :references (list '(:amop :initialization ,class-name))))))
1507         (frob class)
1508         (frob generic-function)
1509         (frob method)
1510         (frob slot-definition))))
1511   (change-class-internal instance new-class initargs))
1512
1513 (defmethod change-class ((instance standard-object)
1514                          (new-class funcallable-standard-class)
1515                          &rest initargs)
1516   (declare (ignore initargs))
1517   (error "You can't change the class of ~S to ~S~@
1518           because it isn't already an instance with metaclass ~S."
1519          instance new-class 'standard-class))
1520
1521 (defmethod change-class ((instance funcallable-standard-object)
1522                          (new-class standard-class)
1523                          &rest initargs)
1524   (declare (ignore initargs))
1525   (error "You can't change the class of ~S to ~S~@
1526           because it isn't already an instance with metaclass ~S."
1527          instance new-class 'funcallable-standard-class))
1528
1529 (defmethod change-class ((instance t) (new-class-name symbol) &rest initargs)
1530   (apply #'change-class instance (find-class new-class-name) initargs))
1531 \f
1532 ;;;; The metaclass BUILT-IN-CLASS
1533 ;;;;
1534 ;;;; This metaclass is something of a weird creature. By this point, all
1535 ;;;; instances of it which will exist have been created, and no instance
1536 ;;;; is ever created by calling MAKE-INSTANCE.
1537 ;;;;
1538 ;;;; But, there are other parts of the protocol we must follow and those
1539 ;;;; definitions appear here.
1540
1541 (macrolet ((def (name args control)
1542                `(defmethod ,name ,args
1543                  (declare (ignore initargs))
1544                  (error 'metaobject-initialization-violation
1545                   :format-control ,(format nil "~@<~A~@:>" control)
1546                   :format-arguments (list ',name)
1547                   :references (list '(:amop :initialization "Class"))))))
1548   (def initialize-instance ((class built-in-class) &rest initargs)
1549     "Cannot ~S an instance of BUILT-IN-CLASS.")
1550   (def reinitialize-instance ((class built-in-class) &rest initargs)
1551     "Cannot ~S an instance of BUILT-IN-CLASS."))
1552
1553 (macrolet ((def (name)
1554                `(defmethod ,name ((class built-in-class)) nil)))
1555   (def class-direct-slots)
1556   (def class-slots)
1557   (def class-direct-default-initargs)
1558   (def class-default-initargs))
1559
1560 (defmethod class-slot-vector (class)
1561   ;; Default method to cause FIND-SLOT-DEFINITION return NIL for all
1562   ;; non SLOT-CLASS classes.
1563   #(nil))
1564
1565 (defmethod validate-superclass ((c class) (s built-in-class))
1566   (or (eq s *the-class-t*) (eq s *the-class-stream*)
1567       ;; FIXME: bad things happen if someone tries to mix in both
1568       ;; FILE-STREAM and STRING-STREAM (as they have the same
1569       ;; layout-depthoid).  Is there any way we can provide a useful
1570       ;; error message?  -- CSR, 2005-05-03
1571       (eq s *the-class-file-stream*) (eq s *the-class-string-stream*)
1572       ;; This probably shouldn't be mixed in with certain other
1573       ;; classes, too, but it seems to work both with STANDARD-OBJECT
1574       ;; and FUNCALLABLE-STANDARD-OBJECT
1575       (eq s *the-class-sequence*)))
1576 \f
1577 ;;; Some necessary methods for FORWARD-REFERENCED-CLASS
1578 (defmethod class-direct-slots ((class forward-referenced-class)) ())
1579 (defmethod class-direct-default-initargs ((class forward-referenced-class)) ())
1580 (macrolet ((def (method)
1581              `(defmethod ,method ((class forward-referenced-class))
1582                 (error "~@<~I~S was called on a forward referenced class:~2I~_~S~:>"
1583                        ',method class))))
1584   (def class-default-initargs)
1585   (def class-precedence-list)
1586   (def class-slots))
1587
1588 (defmethod validate-superclass ((c slot-class)
1589                                 (f forward-referenced-class))
1590   t)
1591 \f
1592 (defmethod add-dependent ((metaobject dependent-update-mixin) dependent)
1593   (pushnew dependent (plist-value metaobject 'dependents)))
1594
1595 (defmethod remove-dependent ((metaobject dependent-update-mixin) dependent)
1596   (setf (plist-value metaobject 'dependents)
1597         (delete dependent (plist-value metaobject 'dependents))))
1598
1599 (defmethod map-dependents ((metaobject dependent-update-mixin) function)
1600   (dolist (dependent (plist-value metaobject 'dependents))
1601     (funcall function dependent)))
1602