summaryrefslogtreecommitdiff
path: root/Lisp/libobjcl.lisp
blob: 6296c46f92bba5c1fda2d633195f9cac5e894f2a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
;;;; Objective-CL, an Objective-C bridge for Common Lisp.
;;;; Copyright (C) 2007  Matthias Andreas Benkard.
;;;;
;;;; This program is free software: you can redistribute it and/or
;;;; modify it under the terms of the GNU Lesser General Public License
;;;; as published by the Free Software Foundation, either version 3 of
;;;; the License, or (at your option) any later version.
;;;;
;;;; This program is distributed in the hope that it will be useful, but
;;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;;;; Lesser General Public License for more details.
;;;;
;;;; You should have received a copy of the GNU Lesser General Public
;;;; License along with this program.  If not, see
;;;; <http://www.gnu.org/licenses/>.

(in-package #:mulk.objective-cl)


(eval-when (:compile-toplevel :load-toplevel :execute)
  (dolist (subdir '("shared_obj/" "obj/"))
    (pushnew (merge-pathnames subdir objcl-asdf:*objc-obj-dir*)
             cffi:*foreign-library-directories*)))

(define-foreign-library libobjcl
  (:unix (:or "libobjcl.so"
              "libobjcl.so.0"
              "libobjcl.dylib"
              "libobjcl.dylib.0"))
  (t (:default "libobjcl")))

(use-foreign-library libobjcl)


(defcfun ("objcl_memmove" memmove) :pointer
  (destination :pointer)
  (source :pointer)
  (length :unsigned-long))

(defcfun ("objcl_initialise_runtime" %initialise-runtime) :void)

(defcfun ("objcl_shutdown_runtime" %shutdown-runtime) :void)

(defcfun ("objcl_invoke_with_types" %objcl-invoke-with-types) :pointer
  (argc :int)
  (superclass-for-send-super :pointer)
  (return_typespec :string)
  (arg_typespecs (:array :string))
  (return_value (:pointer :void))
  (argv (:array (:pointer :void))))

(defcfun ("objcl_find_class" %objcl-find-class) :pointer
  (class-name :string))

(defcfun ("objcl_find_meta_class" %objcl-find-meta-class) :pointer
  (class-name :string))

(defcfun ("objcl_class_name" %objcl-class-name) :string
  (class :pointer))

(defcfun ("objcl_class_superclass" %objcl-class-superclass) :pointer
  (obj :pointer))

(defcfun ("objcl_class_metaclass" %objcl-class-metaclass) :pointer
  (obj :pointer))

(defcfun ("objcl_find_selector" %objcl-find-selector) :pointer
  (selector-name :string))

(defcfun ("objcl_intern_selector" %objcl-intern-selector) :pointer
  (selector-name :string))

(defcfun ("objcl_selector_name" %objcl-selector-name) :string
  (selector :pointer))

(defcfun ("objcl_get_method_implementation"
          %objcl-get-method-implementation)
    :pointer
  (object :pointer)
  (selector :pointer))

(defcfun ("objcl_object_is_class" %objcl-object-is-class) :boolean
  (obj :pointer))

(defcfun ("objcl_object_is_meta_class" %objcl-object-is-meta-class)
    :boolean
  (obj :pointer))

(defcfun ("objcl_object_get_class" %objcl-object-get-class) :pointer
  (obj :pointer))

(defcfun ("objcl_object_get_meta_class" %objcl-object-get-meta-class)
    :pointer
  (obj :pointer))

(defcfun ("objcl_get_runtime_type" %objcl-get-runtime-type) :string)

(defcfun ("objcl_objc2_p" %objcl-objc2-p) :int)

(defcfun ("objcl_sizeof_type" %objcl-sizeof-type) :long
  (typespec :string))

(defcfun ("objcl_sizeof_return_type" %objcl-sizeof-return-type) :long
  (typespec :string))

(defcfun ("objcl_alignof_type" %objcl-alignof-type) :long
  (typespec :string))

(defcfun ("objcl_set_slot_value" %objcl-set-slot-value) :void
  (obj :pointer) ; id
  (slot-name :string)
  (value :pointer)) ; void

(defcfun ("objcl_get_slot_value" %objcl-get-slot-value) :void
  (obj :pointer) ; id
  (slot-name :string)
  (value-out :pointer))

(defcfun ("objcl_get_slot" %objcl-get-slot) :pointer
  (class :pointer) ; Class
  (slot-name :string))

(defcfun ("objcl_get_slot_offset" %objcl-get-slot-offset) :long
  (slot :pointer))

(defcfun ("objcl_class_direct_slots" %objcl-class-direct-slots) :pointer
  (class :pointer) ; Class
  (count :pointer) ; unsigned int
  (element-size :pointer)) ; unsigned int

(defcfun ("objcl_slot_name" %objcl-slot-name) :string
  (slot :pointer)) ; IVAR_T

(defcfun ("objcl_slot_type" %objcl-slot-type) :string
  (slot :pointer)) ; IVAR_T

(defcfun ("objcl_get_nil" %objcl-get-nil) :pointer)
(defcfun objcl-get-yes :long)
(defcfun objcl-get-no :long)

(defcfun ("objcl_create_imp" %objcl-create-imp) :pointer
  (callback :pointer)
  (argc :int)
  (return-typespec :string)
  (arg-typespecs (:array :string)))

(defcfun ("objcl_acquire_lock" %objcl-release-lock) :pointer
  (lock :pointer))

(defcfun ("objcl_release_lock" %objcl-acquire-lock) :pointer
  (lock :pointer))

(defcfun ("objcl_create_class" %objcl-create-class) :pointer
  (class-name :string)
  (superclass :pointer)
  (protocol-numer :int)
  (protocol-names (:array :string))
  (ivar-number :int)
  (ivar-names (:array :string))
  (ivar-typespecs (:array :string)))

(defcfun ("objcl_add_method" %objcl-add-method) :void
  (class :pointer)
  (method-name :pointer)
  (callback :pointer)
  (argc :int)
  (return-typespec :string)
  (arg-typespecs (:array :string))
  (signature :string)
  (registered-p :int))

(defcfun ("objcl_finalise_class" %objcl-finalise-class) :void
  (class :pointer))

(defcfun ("objcl_class_backed_by_lisp_class_p"
          %objcl-class-backed-by-lisp-class-p)
    :int
  (class :pointer))

(defcfun ("objcl_class_set_backed_by_lisp_class"
          %objcl-class-set-backed-by-lisp-class)
    :void
  (class :pointer)
  (backed-p :int))

(defcfun ("objcl_object_backed_by_lisp_class_p"
          %objcl-object-backed-by-lisp-class-p)
    :int
  (instance :pointer))

(defcvar *objcl-current-exception-lock* :pointer)
(defcvar *objcl-current-exception* :pointer)

(defun objcl-get-nil ()
  ;; %OBJCL-GET-NIL can return NIL for CLISP, which CFFI refuses to
  ;; accept as an argument to POINTER-EQ.  This is weird.
  (or (%objcl-get-nil) (make-pointer 0)))

(defun initialise-runtime ()
  "Initialise the Objective-C runtime.

## Description:

The function __initialise-runtime__ makes all the necessary arrangements
for object instantiation and method calls to work.  In particular, it
creates an autorelease pool in order to make the use of Objective-C's
semiautomatic reference counting memory management possible, which is
used internally by Objective-CL.

Note that, as the autorelease pool created by __initialise-runtime__ is
currently only deallocated and its containees released when
__shutdown-runtime__ is called, it is generally advisable to make use of
AppKit's automatic creation and deletion auf autorelease pools, if
possible.  Naturally, AppKit-based applications need not worry about
this, but be aware that they do need to call __initialise-runtime__
before making any other Objective-C calls.


## See also:

  __shutdown-runtime__"

  (when (zerop *runtime-initialisation-level*)
    (%initialise-runtime))
  (atomically (incf *runtime-initialisation-level*)))


(defun shutdown-runtime ()
  "Shut the Objective-C runtime down.

## Description:

The function __shutdown-runtime__ cleans the environment up.  In
particular, it tries to release all the objects retained in any
autorelease pools created by __initialise-runtime__.

Note that even if you make use of AppKit, which manages its own
autorelease pools, you must call __initialise-runtime__ before making
any Objective-C calls, and you should call __shutdown-runtime__ when you
are finished with Objective-C, since Objective-CL makes use of
autoreleased objects internally before you are even able to retrieve any
objects or classes, let alone send messages to them.


## See also:

  __initialise-runtime__"

  (when (zerop (atomically (decf *runtime-initialisation-level*)))
    (%shutdown-runtime)))


(declaim (ftype (function ((or string symbol) &optional t)
                          (or null objective-c-class))
                find-objc-class))
(defun find-objc-class (class-name &optional errorp)
  "Retrieve an Objective-C class by name.

## Arguments and Values:

*class-name* --- a **symbol** or a **string**.

*errorp* --- a **generalized boolean**.

Returns: *class* --- an __objc-class__ object representing the Objective
C class whose name is *class-name*.


## Description:

If no Objective-C class named by *class-name* is found, the behaviour
depends on *errorp*: If *errorp* is **true**, an error is signaled.  If
*errorp* is **false** (which is the default), __nil__ is returned.

If *class-name* is a **symbol** which does not contain a hyphen, its
**name** is converted to **lowercase** except for the first letter,
which is left intact, and the resulting **string** used as if directly
given as an **argument** to __find-objc-class__.

If *class-name* is a **symbol** which contains a hyphen, its **name**
is split into components separated by hyphens and each component
converted into a **string** according to the following rules:

1. The first component is fully converted to **uppercase** except for
   its first letter, which is left intact.

2. Any additional components have all of their letters converted to
   **lowercase**, except for their first letters, which are left intact.

After that, the components are concatenated in order and the resulting
**string** used as if directly given as an **argument** to
__find-objc-class__.


## Examples:

    (find-objc-class \"NSObject\")     ;=> #<OBJC-CLASS NSObject>
    (find-objc-class 'ns-object)     ;=> #<OBJC-CLASS NSObject>
    (find-objc-class 'nsobject)      ;=> NIL


## Rationale:

The first component of an Objective-C class name is conventionally
thought of as a namespace identifier.  It is therefore sensible to
expect it to be converted to **uppercase** by default, which is the
conventional case for namespace identifiers in Objective-C."

  (let ((class
         (etypecase class-name
           (string (find-objc-class-by-name class-name))
           (symbol (find-objc-class-by-name
                    (symbol->objc-class-name class-name))))))
    (or class (if errorp
                  (error "Found no Objective-C class named ~S."
                         class-name)
                  nil))))


(declaim (ftype (function (string) (or null objective-c-class))
                find-objc-class-by-name))
(defun find-objc-class-by-name (class-name-string)
  ;; Note that this function is able to find classes that are not yet
  ;; registered with the Objective-C runtime simply by looking for an
  ;; extant CLOS class definition.
  ;;
  ;; This is important, as FIND-OBJC-CLASS-BY-NAME is called more often
  ;; than you might think.  For instance, doing a (PRIMITIVE-INVOKE
  ;; class ...) will cause (OBJECT-GET-CLASS class) to be called at some
  ;; point, which would otherwise fail.  Of course, doing a method
  ;; invocation on the class will cause the class to be registered along
  ;; the way as well.
  (let ((class-name (objc-class-name->symbol class-name-string))
        (class-ptr (%objcl-find-class class-name-string)))
    (or (find-class class-name nil)
        (if (objc-pointer-null class-ptr)
            nil
            (let ((superclass (let ((potential-superclass
                                     (objcl-class-superclass/pointer class-ptr)))
                                (if potential-superclass
                                    (foreign-class-ensure-registered
                                     potential-superclass)
                                    (find-class 'id)))))
              (c2mop:ensure-class class-name
                                  :metaclass (class-name
                                              (find-objc-meta-class
                                               class-name-string))
                                  :pointer class-ptr
                                  :wrapped-foreign-class class-name-string
                                  ;; FIXME: It might be desirable to do
                                  ;; set the list of direct superclasses
                                  ;; to something like the following:
                                  ;;
                                  ;;  (if (string= class-name-string "NSException")
                                  ;;      (list superclass (find-class 'serious-condition))
                                  ;;      (list superclass))
                                  ;;
                                  ;; This will fail, as subclassing
                                  ;; CONDITION means not subclassing a
                                  ;; STANDARD-CLASS.  Also, care would
                                  ;; have to be taken not to use
                                  ;; MAKE-INSTANCE but MAKE-CONDITION
                                  ;; for anything derived from
                                  ;; NSException.
                                  :direct-superclasses (list superclass)))))))


(defun find-objc-meta-class (meta-class-name &optional errorp)
  (let ((meta-class
         (etypecase meta-class-name
           (string (find-objc-meta-class-by-name meta-class-name))
           (symbol (find-objc-meta-class-by-name
                    (symbol->objc-class-name meta-class-name))))))
    (or meta-class (if errorp
                       (error "Found no Objective-C metaclass named ~S."
                              meta-class-name)
                       nil))))


(defun find-objc-meta-class-by-name (class-name-string)
  (let ((class-ptr (%objcl-find-meta-class class-name-string)))
    (if (objc-pointer-null class-ptr)
        nil
        (let* ((class-name (objc-meta-class-name->symbol class-name-string))
               ;; We first determine the superclass of the class that
               ;; this metaclass is the metaclass of, because we cannot
               ;; determine a metaclass' superclass directly.
               (non-meta-superclass (objcl-class-superclass/pointer
                                     (%objcl-find-class class-name-string)))
               ;; If such a non-meta-superclass is found, we look for a
               ;; metaclass with the same name and take that as our
               ;; superclass.  Otherwise, OBJECTIVE-C-CLASS should be
               ;; quite the most correct choice.
               (superclass (if non-meta-superclass
                               (find-objc-meta-class
                                (%objcl-class-name
                                 (pointer-to
                                  (foreign-class-ensure-registered
                                   non-meta-superclass))))
                               (find-class 'objective-c-meta-class)))
               ;; If there is no superclass, we are the root metaclass.
               ;; As we cannot assign ourselves as our own metaclass
               ;; (which is a pity, because it would be the correct thing
               ;; to do), we generate a fake metaclass for ourselves that
               ;; is almost the same as ourselves except for its own
               ;; metaclass, which is OBJECTIVE-C-META-CLASS.  (As we are
               ;; probably +NS-OBJECT, this fake metaclass will be called
               ;; ++NS-OBJECT.)
               ;;
               ;; If the superclass is the root metaclass, we take it as
               ;; our metaclass, because the root metaclass is the
               ;; metaclass of all metaclasses.
               ;;
               ;; Otherwise, we use the metaclass of the superclass as
               ;; our own, which will always get us the root metaclass.
               (metaclass
                (if non-meta-superclass
                    (if (typep (class-of superclass)
                               'objective-c-meta-class)
                        superclass
                        (class-of superclass))
                    (let ((fake-metaclass-name
                           (objc-fake-meta-class-name->symbol class-name-string)))
                      (or (find-class fake-metaclass-name nil)
                          (c2mop:ensure-class fake-metaclass-name
                                              :metaclass 'objective-c-meta-class
                                              :pointer class-ptr
                                              :direct-superclasses (list superclass)))))))
          (or (find-class class-name nil)
              (c2mop:ensure-class class-name
                                  :metaclass metaclass
                                  :pointer class-ptr
                                  :direct-superclasses (list superclass)))))))


(defun objc-pointer-null (pointer)
  (or (cffi:null-pointer-p pointer)
      (cffi:pointer-eq pointer (objcl-get-nil))))


(defun objc-null (value)
  (or (null value)
      (and (typep value 'c-pointer-wrapper)
           (objc-pointer-null (pointer-to value)))))


(defmacro objc-or (&rest forms)
  (let ((sym (gensym)))
    `(let ((,sym ,(first forms)))
       (if (objc-null ,sym)
           ,(if (rest forms)
                `(objc-or ,@(rest forms))
                'nil)
           ,sym))))


(declaim (ftype (function (string) (or null selector))
                find-selector-by-name))
(defun find-selector-by-name (selector-name)
  (let ((selector-ptr (%objcl-find-selector selector-name)))
    (if (cffi:null-pointer-p selector-ptr)
        nil
        (intern-pointer-wrapper 'selector :pointer selector-ptr))))


(defun intern-selector-by-name (selector-name)
  (let ((selector-ptr (%objcl-intern-selector selector-name)))
    (assert (not (cffi:null-pointer-p selector-ptr))
            (selector-ptr)
            "%OBJCL-INTERN-SELECTOR must always return a selector.")
    (intern-pointer-wrapper 'selector :pointer selector-ptr)))


(declaim (ftype (function ((or objective-c-class id exception)) string)
                objc-class-name))
(defun objc-class-name (class)
  "Find the name of a class.

## Arguments and Values:

*class* --- an **object** of **type** __objc-id__ or __objc-class__.

Returns: *name* --- a **string**.


## Description:

__objc-class-name__ returns the name of *class*.


## Examples:

    (objc-class-name (find-objc-class 'ns-object))  ;=> \"NSObject\"


## Note:

If *x* is an **object** of **type** __objc-id__ or __objc-class__:

    (objc-eql x (find-objc-class (objc-class-name x)))  ;=> T

If *name* is the name of an existing class:

    (equal name (objc-class-name (find-objc-class name)))  ;=> T


## See Also:

  __find-objc-class__"
  (declare (type (or objective-c-class id exception) class))
  (%objcl-class-name (pointer-to class)))


(declaim (ftype (function (selector) string) selector-name))
(defun selector-name (selector)
  "Find the name of a selector.

## Arguments and Values:

*selector* --- an **object** of **type** __selector__.

Returns: *name* --- a **string**.


## Description:

__selector-name__ returns the name of *selector*.


## Examples:

    (selector-name (selector '(:string-with-c-string :encoding)))
     ;=> \"stringWithCString:encoding:\"


## Note:

If *x* is an **object** of **type** __selector__:

    (objc-equal x (find-selector (selector-name x)))  ;=> T

If *name* is the name of an existing selector:

    (equal name (selector-name (find-selector name)))  ;=> T


## See Also:

  __find-selector__, __selector__"
  (declare (type selector selector))
  (%objcl-selector-name (pointer-to selector)))


(declaim (ftype (function ((or id objective-c-class exception) selector) t)
                get-method-implementation))
(defun get-method-implementation (object selector)
  (declare (type selector selector))
  (%objcl-get-method-implementation (pointer-to object)
                                    (pointer-to selector)))


(declaim (ftype (function ((or selector symbol string list) &optional t)
                          (or null selector))
                find-selector))
(defun find-selector (selector-name &optional (errorp t))
  "Retrieve a method selector by name.

## Arguments and Values:

*selector-name* --- a **string**, a **symbol**, or a **list** of **symbol**s.

*errorp* --- a **generalized boolean**.  The default is **true**.

Returns: *selector* --- a __selector__ object, or __nil__.


## Description:

If *selector-name* is a **string**, the __selector__ named by that
string is returned.  If no __selector__ with the given name exists,
either __nil__ is returned if errorp is **false**, or an error of type
__no-such-selector__ is signaled if errorp is **true**.

If *selector-name* is a **symbol**, it is treated the same as a **list**
whose only element is the **symbol**.

If *selector-name* is a **list** of **symbol**s, all **symbol**s are
first split into parts separated by hyphens and each part converted into
a **string** according to the following rules:

1. 1. If the keywords' **symbol name**s do contain **lowercase**
      **character**s, their case is left intact.

   2. If the keywords' **symbol name**s do not contain any **lowercase**
      **character**s, the following steps are taken in order to adjust
      their case.

      1. The first part is fully converted to **lowercase**.

      2. Any additional parts are also fully converted to **lowercase**
         except for their first letters, which are left intact.

2. If the symbol is a **keyword**, the resulting **string** is suffixed
   by a **colon** (`:').

After that, all parts are concatenated in order to form a
single *selector name component*.  The *selector name components* are in
turn concatenated in order to form the **string** that identifies the
selector, which is used as if given directly as an argument to a call to
__find-selector__.

Note that the conversion rules for selector names are identical to those
by which __invoke__ converts its arguments into a *message name*.


## Examples:

    (find-selector \"self\")       ;=> #<SELECTOR `self'>
    (find-selector '(self))      ;=> #<SELECTOR `self'>
    (find-selector 'self)        ;=> #<SELECTOR `self'>

    (find-selector \"stringWithCString:encoding:\")
      ;=> #<SELECTOR `stringWithCString:encoding:'>

    (find-selector '(:string-with-c-string :encoding))
      ;=> #<SELECTOR `stringWithCString:encoding:'>

    #.(setq \\*readtable\\* (copy-readtable)) 
    #.(setf (readtable-case \\*readtable\\*) :invert)
    (find-selector '(:stringWithCString :encoding))
      ;=> #<SELECTOR `stringWithCString:encoding:'>


## Note:

Setting the **readtable case** of the **current readtable** to `:INVERT`
is a good way of making the Lisp system behave as traditionally as
possible while making Objective-C method names case-sensitive.

On the other hand, writing all method names in lower case while
separating parts by hyphens works nicely in all of the `:INVERT`,
`:UPCASE`, `:DOWNCASE`, and `:PRESERVE` modes as well as Allegro CL's
*modern mode*.


## See also:

  __intern-selector__, __selector__"

  (or (typecase selector-name
        (string (find-selector-by-name selector-name))
        (symbol (find-selector-by-name (symbol-list->message-name
                                        (list selector-name))))
        (list   (find-selector-by-name (symbol-list->message-name
                                        selector-name))))
      (and errorp
           (error (make-condition 'no-such-selector :designator selector-name)))))


(defun intern-selector (selector-name)
  "Retrieve a method selector by name, or create it if it does not exist.

## Arguments and Values:

*selector-name* --- a **string**, a **symbol**, or a **list** of **symbol**s.

Returns: *selector* --- a __selector__ object.


## Description:

If *selector-name* is a **string**, the __selector__ named by that
string is returned.  If no __selector__ with the given name exists, such
a selector is created and registered with the Objective-C runtime, after
which it is returned.

If *selector-name* is a **symbol**, it is treated the same as a **list**
whose only element is the **symbol**.

If *selector-name* is a **list** of **symbol**s, all **symbol**s are
first split into parts separated by hyphens and each part converted into
a **string** according to the following rules:

1. 1. If the keywords' **symbol name**s do contain **lowercase**
      **character**s, their case is left intact.

   2. If the keywords' **symbol name**s do not contain any **lowercase**
      **character**s, the following steps are taken in order to adjust
      their case.

      1. The first part is fully converted to **lowercase**.

      2. Any additional parts are also fully converted to **lowercase**
         except for their first letters, which are left intact.

2. If the symbol is a **keyword**, the resulting **string** is suffixed
   by a **colon** (`:').

After that, all parts are concatenated in order to form a
single *selector name component*.  The *selector name components* are in
turn concatenated in order to form the **string** that identifies the
selector, which is used as if given directly as an argument to a call to
__intern-selector__.

Note that the conversion rules for selector names are identical to those
by which __invoke__ converts its arguments into a *message name*.


## Examples:

    (intern-selector \"self\")       ;=> #<SELECTOR `self'>
    (intern-selector '(self))      ;=> #<SELECTOR `self'>
    (intern-selector 'self)        ;=> #<SELECTOR `self'>

    (intern-selector \"stringWithCString:encoding:\")
      ;=> #<SELECTOR `stringWithCString:encoding:'>

    (intern-selector '(:string-with-c-string :encoding))
      ;=> #<SELECTOR `stringWithCString:encoding:'>

    #.(setq \\*readtable\\* (copy-readtable)) 
    #.(setf (readtable-case \\*readtable\\*) :invert)
    (intern-selector '(:stringWithCString :encoding))
      ;=> #<SELECTOR `stringWithCString:encoding:'>


## Note:

Setting the **readtable case** of the **current readtable** to `:INVERT`
is a good way of making the Lisp system behave as traditionally as
possible while making Objective-C method names case-sensitive.

On the other hand, writing all method names in lower case while
separating parts by hyphens works nicely in all of the `:INVERT`,
`:UPCASE`, `:DOWNCASE`, and `:PRESERVE` modes as well as Allegro CL's
*modern mode*.


## See also:

  __find-selector__, __selector__"

  (typecase selector-name
    (string (intern-selector-by-name selector-name))
    (symbol (intern-selector-by-name (symbol-list->message-name
                                      (list selector-name))))
    (list   (intern-selector-by-name (symbol-list->message-name
                                      selector-name)))))

(defun pointer (thing)
  (etypecase thing
    (c-pointer thing)
    (c-pointer-wrapper (pointer-to thing))))

(defun object-is-class-p (obj)
  (%objcl-object-is-class (pointer obj)))

(defun object-is-meta-class-p (obj)
  (%objcl-object-is-meta-class (pointer obj)))

(defun object-get-class (obj)
  (find-objc-class-by-name
   (%objcl-class-name (%objcl-object-get-class (pointer obj)))))

(defun object-get-meta-class (obj)
  (find-objc-meta-class-by-name
   (%objcl-class-name (%objcl-object-get-class (pointer obj)))))

(defun objcl-class-superclass/pointer (class-ptr)
  (let ((superclass-ptr (%objcl-class-superclass class-ptr)))
    (if (and (not (null-pointer-p superclass-ptr))
             (%objcl-object-is-class superclass-ptr))
        (intern-pointer-wrapper t :pointer superclass-ptr)
        nil)))

(defun objcl-class-superclass (class)
  (objcl-class-superclass/pointer (pointer-to class)))

(defun objcl-create-class (class-name superclass
                           protocol-names
                           ivar-names ivar-typespecs)
  (let* ((ivar-typestrings (mapcar #'print-typespec-to-string ivar-typespecs)))
    (with-foreign-string-pool (register-temporary-string
                               allocate-temporary-string)
      (with-foreign-objects ((%protocol-names :pointer (length protocol-names))
                             (%ivar-names :pointer (length ivar-names))
                             (%ivar-typestrings :pointer (length ivar-typestrings)))
        (flet ((fill-foreign-array-from-list (array list type)
                 (loop for element in list
                       for i from 0
                       do (setf (mem-aref array type i) element))))
          (loop for (array . list)
                  in (list (cons %protocol-names protocol-names)
                           (cons %ivar-names ivar-names)
                           (cons %ivar-typestrings ivar-typestrings))
                do (fill-foreign-array-from-list
                        array
                        (mapcar #'allocate-temporary-string
                                list)
                        :pointer)))
        (%objcl-create-class class-name
                             (pointer-to superclass)
                             (length protocol-names)
                             %protocol-names
                             (length ivar-names)
                             %ivar-names
                             %ivar-typestrings)))))

;;; (@* "Low-level Data Conversion")
(eval-when (:compile-toplevel :load-toplevel)
  ;; In order to be able to dispatch over pointer types, we need to
  ;; define an alias of the implementation's own pointer class.  Note
  ;; that this may be T (in GNU CLISP, for example), so it's a good idea
  ;; to use CHECK-TYPE in the method body.
  (unless (find-class 'foreign-pointer nil)
    (setf (find-class 'foreign-pointer nil)
          (class-of (make-pointer 0)))
    (ignore-errors
      (deftype foreign-pointer ()
        '(satisfies cffi:pointerp)))))


(declaim (ftype (function ((or selector string symbol list)) selector)
                selector))
(defun selector (designator)
  "Convert an object into a selector.

## Arguments and Values:

*designator* --- a *selector designator*.


## Description:

*selector-designator* must be a valid *selector designator*, that is:
either a __selector__ object or one of a **symbol**, a **string**, or a
**list** of **symbol**s representing a __selector__.

If *selector-designator* is a **string** or a **list** of **symbol**s,
__intern-selector__ is called and the value returned.

If *selector-designator* is a single **symbol**, it is treated as if it
were a **list** whose **car** is the **symbol** and whose **cdr** is
__nil__.

If *selector-designator* is a __selector__, it is simply returned.


## Examples:

    (selector \"self\")       ;=> #<SELECTOR `self'>
    (selector '(self))      ;=> #<SELECTOR `self'>
    (selector 'self)        ;=> #<SELECTOR `self'>
    (selector *)            ;=> #<SELECTOR `self'>

    (selector 'selph)       ; error

    (selector \"stringWithCString:encoding:\")
      ;=> #<SELECTOR `stringWithCString:encoding:'>

    (selector '(:string-with-c-string :encoding))
      ;=> #<SELECTOR `stringWithCString:encoding:'>

    #.(setq \\*readtable\\* (copy-readtable)) 
    #.(setf (readtable-case \\*readtable\\*) :invert)
    (selector '(:stringWithCString :encoding))
      ;=> #<SELECTOR `stringWithCString:encoding:'>


## Note:

Setting the **readtable case** of the **current readtable** to `:INVERT`
is a good way of making the Lisp system behave as traditionally as
possible while making Objective-C method names case-sensitive.

On the other hand, writing all method names in lower case while
separating parts by hyphens works nicely in all of the `:INVERT`,
`:UPCASE`, `:DOWNCASE`, and `:PRESERVE` modes as well as Allegro CL's
*modern mode*.


## See also:

  __find-selector__, __intern-selector__"

  (etypecase designator
    (selector designator)
    (symbol (selector (list designator)))
    ((or string list)
     (intern-selector designator))))


;;;; (@* "Helper functions")
(defun sizeof (typespec)
  (%objcl-sizeof-type (print-typespec-to-string typespec)))

(defun alignof (typespec)
  (%objcl-alignof-type (print-typespec-to-string typespec)))

(defun return-type-sizeof (typespec)
  (%objcl-sizeof-return-type (print-typespec-to-string typespec)))

(defun runtime-type ()
  (let ((runtime (%objcl-get-runtime-type)))
    (assert (member runtime '("GNU" "NeXT") :test #'string=)
            (runtime)
            "Unkown Objective-C runtime type ~S.  Allowed: (\"GNU\" \"NeXT\")."
            runtime)
    (cond ((string= runtime "GNU") :gnu)
          ((string= runtime "NeXT") :next))))

(defun objc-2.0-runtime-p ()
  (not (zerop (%objcl-objc2-p))))


;;;; (@* "Slot access")
(defun objcl-slot-type (slot)
  (%objcl-slot-type slot))

(defun objcl-slot-name (slot)
  (%objcl-slot-name slot))

(defun objcl-class-direct-slots (class)
  (if (typep class 'objective-c-class)
      (objcl-class-direct-slots/pointer (pointer-to class))
      nil))

(defun objcl-class-direct-slots/pointer (class-ptr)
  (with-foreign-objects ((count-ptr :unsigned-int)
                         (element-size-ptr :unsigned-int))
    (let ((array-pointer (%objcl-class-direct-slots class-ptr
                                                    count-ptr
                                                    element-size-ptr)))
      (unless (zerop (mem-ref count-ptr :unsigned-int))
        (unwind-protect
            (loop with element-size = (mem-ref element-size-ptr :unsigned-int)
                  with count = (mem-ref count-ptr :unsigned-int)
                  for i from 0 below count
                  for current-slot = array-pointer
                    then (inc-pointer current-slot element-size)
                  collecting (mem-ref current-slot :pointer))
          (foreign-free array-pointer))))))

(defun objcl-class-backed-by-lisp-class-p/pointer (class-ptr)
  (not (zerop (%objcl-class-backed-by-lisp-class-p class-ptr))))

(defun objcl-class-set-backed-by-lisp-class/pointer (class-ptr backed-p)
  (%objcl-class-set-backed-by-lisp-class class-ptr (if backed-p 1 0)))

(defun objcl-object-backed-by-lisp-class-p/pointer (object-ptr)
  (not (zerop (%objcl-object-backed-by-lisp-class-p object-ptr))))

(defun objcl-object-backed-by-lisp-class-p (instance)
  (objcl-object-backed-by-lisp-class-p/pointer (pointer-to instance)))