summaryrefslogtreecommitdiff
path: root/lib/rdoc/parser/c.rb
blob: b89aaa6dcc9795e756a6615327dbce54ea35958d (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
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
# frozen_string_literal: true
require 'tsort'

##
# RDoc::Parser::C attempts to parse C extension files.  It looks for
# the standard patterns that you find in extensions: +rb_define_class+,
# +rb_define_method+ and so on.  It tries to find the corresponding
# C source for the methods and extract comments, but if we fail
# we don't worry too much.
#
# The comments associated with a Ruby method are extracted from the C
# comment block associated with the routine that _implements_ that
# method, that is to say the method whose name is given in the
# +rb_define_method+ call. For example, you might write:
#
#   /*
#    * Returns a new array that is a one-dimensional flattening of this
#    * array (recursively). That is, for every element that is an array,
#    * extract its elements into the new array.
#    *
#    *    s = [ 1, 2, 3 ]           #=> [1, 2, 3]
#    *    t = [ 4, 5, 6, [7, 8] ]   #=> [4, 5, 6, [7, 8]]
#    *    a = [ s, t, 9, 10 ]       #=> [[1, 2, 3], [4, 5, 6, [7, 8]], 9, 10]
#    *    a.flatten                 #=> [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
#    */
#    static VALUE
#    rb_ary_flatten(VALUE ary)
#    {
#        ary = rb_obj_dup(ary);
#        rb_ary_flatten_bang(ary);
#        return ary;
#    }
#
#    ...
#
#    void
#    Init_Array(void)
#    {
#      ...
#      rb_define_method(rb_cArray, "flatten", rb_ary_flatten, 0);
#
# Here RDoc will determine from the +rb_define_method+ line that there's a
# method called "flatten" in class Array, and will look for the implementation
# in the method +rb_ary_flatten+. It will then use the comment from that
# method in the HTML output. This method must be in the same source file
# as the +rb_define_method+.
#
# The comment blocks may include special directives:
#
# [Document-class: +name+]
#   Documentation for the named class.
#
# [Document-module: +name+]
#   Documentation for the named module.
#
# [Document-const: +name+]
#   Documentation for the named +rb_define_const+.
#
#   Constant values can be supplied on the first line of the comment like so:
#
#     /* 300: The highest possible score in bowling */
#     rb_define_const(cFoo, "PERFECT", INT2FIX(300));
#
#   The value can contain internal colons so long as they are escaped with a \
#
# [Document-global: +name+]
#   Documentation for the named +rb_define_global_const+
#
# [Document-variable: +name+]
#   Documentation for the named +rb_define_variable+
#
# [Document-method\: +method_name+]
#   Documentation for the named method.  Use this when the method name is
#   unambiguous.
#
# [Document-method\: <tt>ClassName::method_name</tt>]
#   Documentation for a singleton method in the given class.  Use this when
#   the method name alone is ambiguous.
#
# [Document-method\: <tt>ClassName#method_name</tt>]
#   Documentation for a instance method in the given class.  Use this when the
#   method name alone is ambiguous.
#
# [Document-attr: +name+]
#   Documentation for the named attribute.
#
# [call-seq:  <i>text up to an empty line</i>]
#   Because C source doesn't give descriptive names to Ruby-level parameters,
#   you need to document the calling sequence explicitly
#
# In addition, RDoc assumes by default that the C method implementing a
# Ruby function is in the same source file as the rb_define_method call.
# If this isn't the case, add the comment:
#
#   rb_define_method(....);  // in filename
#
# As an example, we might have an extension that defines multiple classes
# in its Init_xxx method. We could document them using
#
#   /*
#    * Document-class:  MyClass
#    *
#    * Encapsulate the writing and reading of the configuration
#    * file. ...
#    */
#
#   /*
#    * Document-method: read_value
#    *
#    * call-seq:
#    *   cfg.read_value(key)            -> value
#    *   cfg.read_value(key} { |key| }  -> value
#    *
#    * Return the value corresponding to +key+ from the configuration.
#    * In the second form, if the key isn't found, invoke the
#    * block and return its value.
#    */

class RDoc::Parser::C < RDoc::Parser

  parse_files_matching(/\.(?:([CcHh])\1?|c([+xp])\2|y)\z/)

  include RDoc::Text

  ##
  # Maps C variable names to names of Ruby classes or modules

  attr_reader :classes

  ##
  # C file the parser is parsing

  attr_accessor :content

  ##
  # Dependencies from a missing enclosing class to the classes in
  # missing_dependencies that depend upon it.

  attr_reader :enclosure_dependencies

  ##
  # Maps C variable names to names of Ruby classes (and singleton classes)

  attr_reader :known_classes

  ##
  # Classes found while parsing the C file that were not yet registered due to
  # a missing enclosing class.  These are processed by do_missing

  attr_reader :missing_dependencies

  ##
  # Maps C variable names to names of Ruby singleton classes

  attr_reader :singleton_classes

  ##
  # The TopLevel items in the parsed file belong to

  attr_reader :top_level

  ##
  # Prepares for parsing a C file.  See RDoc::Parser#initialize for details on
  # the arguments.

  def initialize top_level, file_name, content, options, stats
    super

    @known_classes = RDoc::KNOWN_CLASSES.dup
    @content = handle_tab_width handle_ifdefs_in @content
    @file_dir = File.dirname @file_name

    @classes           = load_variable_map :c_class_variables
    @singleton_classes = load_variable_map :c_singleton_class_variables

    @markup = @options.markup

    # class_variable => { function => [method, ...] }
    @methods = Hash.new { |h, f| h[f] = Hash.new { |i, m| i[m] = [] } }

    # missing variable => [handle_class_module arguments]
    @missing_dependencies = {}

    # missing enclosure variable => [dependent handle_class_module arguments]
    @enclosure_dependencies = Hash.new { |h, k| h[k] = [] }
    @enclosure_dependencies.instance_variable_set :@missing_dependencies,
                                                  @missing_dependencies

    @enclosure_dependencies.extend TSort

    def @enclosure_dependencies.tsort_each_node &block
      each_key(&block)
    rescue TSort::Cyclic => e
      cycle_vars = e.message.scan(/"(.*?)"/).flatten

      cycle = cycle_vars.sort.map do |var_name|
        delete var_name

        var_name, type, mod_name, = @missing_dependencies[var_name]

        "#{type} #{mod_name} (#{var_name})"
      end.join ', '

      warn "Unable to create #{cycle} due to a cyclic class or module creation"

      retry
    end

    def @enclosure_dependencies.tsort_each_child node, &block
      fetch(node, []).each(&block)
    end
  end

  ##
  # Scans #content for rb_define_alias

  def do_aliases
    @content.scan(/rb_define_alias\s*\(
                   \s*(\w+),
                   \s*"(.+?)",
                   \s*"(.+?)"
                   \s*\)/xm) do |var_name, new_name, old_name|
      class_name = @known_classes[var_name]

      unless class_name then
        @options.warn "Enclosing class or module %p for alias %s %s is not known" % [
          var_name, new_name, old_name]
        next
      end

      class_obj = find_class var_name, class_name
      comment = find_alias_comment var_name, new_name, old_name
      comment.normalize
      if comment.to_s.empty? and existing_method = class_obj.method_list.find { |m| m.name == old_name}
        comment = existing_method.comment
      end
      add_alias(var_name, class_obj, old_name, new_name, comment)
    end
  end

  ##
  # Add alias, either from a direct alias definition, or from two
  # method that reference the same function.

  def add_alias(var_name, class_obj, old_name, new_name, comment)
    al = RDoc::Alias.new '', old_name, new_name, ''
    al.singleton = @singleton_classes.key? var_name
    al.comment = comment
    al.record_location @top_level
    class_obj.add_alias al
    @stats.add_alias al
    al
  end

  ##
  # Scans #content for rb_attr and rb_define_attr

  def do_attrs
    @content.scan(/rb_attr\s*\(
                   \s*(\w+),
                   \s*([\w"()]+),
                   \s*([01]),
                   \s*([01]),
                   \s*\w+\);/xm) do |var_name, attr_name, read, write|
      handle_attr var_name, attr_name, read, write
    end

    @content.scan(%r%rb_define_attr\(
                             \s*([\w\.]+),
                             \s*"([^"]+)",
                             \s*(\d+),
                             \s*(\d+)\s*\);
                %xm) do |var_name, attr_name, read, write|
      handle_attr var_name, attr_name, read, write
    end
  end

  ##
  # Scans #content for boot_defclass

  def do_boot_defclass
    @content.scan(/(\w+)\s*=\s*boot_defclass\s*\(\s*"(\w+?)",\s*(\w+?)\s*\)/) do
      |var_name, class_name, parent|
      parent = nil if parent == "0"
      handle_class_module(var_name, :class, class_name, parent, nil)
    end
  end

  ##
  # Scans #content for rb_define_class, boot_defclass, rb_define_class_under
  # and rb_singleton_class

  def do_classes_and_modules
    do_boot_defclass if @file_name == "class.c"

    @content.scan(
      %r(
        (?<var_name>[\w\.]+)\s* =
        \s*rb_(?:
          define_(?:
            class(?: # rb_define_class(class_name_1, parent_name_1)
              \s*\(
                \s*"(?<class_name_1>\w+)",
                \s*(?<parent_name_1>\w+)\s*
              \)
            |
              _under\s*\( # rb_define_class_under(class_under, class_name2, parent_name2...)
                \s* (?<class_under>\w+),
                \s* "(?<class_name_2>\w+)",
                \s*
                (?:
                  (?<parent_name_2>[\w\*\s\(\)\.\->]+) |
                  rb_path2class\("(?<path>[\w:]+)"\)
                )
              \s*\)
            )
          |
            module(?: # rb_define_module(module_name_1)
              \s*\(
                \s*"(?<module_name_1>\w+)"\s*
              \)
            |
              _under\s*\( # rb_define_module_under(module_under, module_name_2)
                \s*(?<module_under>\w+),
                \s*"(?<module_name_2>\w+)"
              \s*\)
            )
          )
      |
        struct_define_without_accessor\s*\( # rb_struct_define_without_accessor(class_name_3, parent_name_3, ...)
          \s*"(?<class_name_3>\w+)",
          \s*(?<parent_name_3>\w+),
          \s*\w+,        # Allocation function
          (?:\s*"\w+",)* # Attributes
          \s*NULL
        \)
      |
        singleton_class\s*\( # rb_singleton_class(target_class_name)
          \s*(?<target_class_name>\w+)
        \)
        )
      )mx
    ) do
      class_name = $~[:class_name_1]
      type = :class
      if class_name
        # rb_define_class(class_name_1, parent_name_1)
        parent_name = $~[:parent_name_1]
        #under = nil
      else
        class_name = $~[:class_name_2]
        if class_name
          # rb_define_class_under(class_under, class_name2, parent_name2...)
          parent_name = $~[:parent_name_2] || $~[:path]
          under = $~[:class_under]
        else
          class_name = $~[:class_name_3]
          if class_name
            # rb_struct_define_without_accessor(class_name_3, parent_name_3, ...)
            parent_name = $~[:parent_name_3]
            #under = nil
          else
            type = :module
            class_name = $~[:module_name_1]
            #parent_name = nil
            if class_name
              # rb_define_module(module_name_1)
              #under = nil
            else
              class_name = $~[:module_name_2]
              if class_name
                # rb_define_module_under(module_under, module_name_1)
                under = $~[:module_under]
              else
                # rb_singleton_class(target_class_name)
                target_class_name = $~[:target_class_name]
                handle_singleton $~[:var_name], target_class_name
                next
              end
            end
          end
        end
      end

      handle_class_module($~[:var_name], type, class_name, parent_name, under)
    end
  end

  ##
  # Scans #content for rb_define_variable, rb_define_readonly_variable,
  # rb_define_const and rb_define_global_const

  def do_constants
    @content.scan(%r%\Wrb_define_
                   ( variable          |
                     readonly_variable |
                     const             |
                     global_const        )
               \s*\(
                 (?:\s*(\w+),)?
                 \s*"(\w+)",
                 \s*(.*?)\s*\)\s*;
                 %xm) do |type, var_name, const_name, definition|
      var_name = "rb_cObject" if !var_name or var_name == "rb_mKernel"
      handle_constants type, var_name, const_name, definition
    end

    @content.scan(%r%
                  \Wrb_curses_define_const
                  \s*\(
                    \s*
                    (\w+)
                    \s*
                  \)
                  \s*;%xm) do |consts|
      const = consts.first

      handle_constants 'const', 'mCurses', const, "UINT2NUM(#{const})"
    end

    @content.scan(%r%
                  \Wrb_file_const
                  \s*\(
                    \s*
                    "([^"]+)",
                    \s*
                    (.*?)
                    \s*
                  \)
                  \s*;%xm) do |name, value|
      handle_constants 'const', 'rb_mFConst', name, value
    end
  end


  ##
  # Scans #content for rb_include_module

  def do_includes
    @content.scan(/rb_include_module\s*\(\s*(\w+?),\s*(\w+?)\s*\)/) do |c,m|
      next unless cls = @classes[c]
      m = @known_classes[m] || m

      comment = new_comment '', @top_level, :c
      incl = cls.add_include RDoc::Include.new(m, comment)
      incl.record_location @top_level
    end
  end

  ##
  # Scans #content for rb_define_method, rb_define_singleton_method,
  # rb_define_module_function, rb_define_private_method,
  # rb_define_global_function and define_filetest_function

  def do_methods
    @content.scan(%r%rb_define_
                   (
                      singleton_method |
                      method           |
                      module_function  |
                      private_method
                   )
                   \s*\(\s*([\w\.]+),
                     \s*"([^"]+)",
                     \s*(?:RUBY_METHOD_FUNC\(|VALUEFUNC\(|\(METHOD\))?(\w+)\)?,
                     \s*(-?\w+)\s*\)
                   (?:;\s*/[*/]\s+in\s+(\w+?\.(?:cpp|c|y)))?
                 %xm) do |type, var_name, meth_name, function, param_count, source_file|

      # Ignore top-object and weird struct.c dynamic stuff
      next if var_name == "ruby_top_self"
      next if var_name == "nstr"

      var_name = "rb_cObject" if var_name == "rb_mKernel"
      handle_method(type, var_name, meth_name, function, param_count,
                    source_file)
    end

    @content.scan(%r%rb_define_global_function\s*\(
                             \s*"([^"]+)",
                             \s*(?:RUBY_METHOD_FUNC\(|VALUEFUNC\()?(\w+)\)?,
                             \s*(-?\w+)\s*\)
                (?:;\s*/[*/]\s+in\s+(\w+?\.[cy]))?
                %xm) do |meth_name, function, param_count, source_file|
      handle_method("method", "rb_mKernel", meth_name, function, param_count,
                    source_file)
    end

    @content.scan(/define_filetest_function\s*\(
                     \s*"([^"]+)",
                     \s*(?:RUBY_METHOD_FUNC\(|VALUEFUNC\()?(\w+)\)?,
                     \s*(-?\w+)\s*\)/xm) do |meth_name, function, param_count|

      handle_method("method", "rb_mFileTest", meth_name, function, param_count)
      handle_method("singleton_method", "rb_cFile", meth_name, function,
                    param_count)
    end
  end

  ##
  # Creates classes and module that were missing were defined due to the file
  # order being different than the declaration order.

  def do_missing
    return if @missing_dependencies.empty?

    @enclosure_dependencies.tsort.each do |in_module|
      arguments = @missing_dependencies.delete in_module

      next unless arguments # dependency on existing class

      handle_class_module(*arguments)
    end
  end

  ##
  # Finds the comment for an alias on +class_name+ from +new_name+ to
  # +old_name+

  def find_alias_comment class_name, new_name, old_name
    content =~ %r%((?>/\*.*?\*/\s+))
                  rb_define_alias\(\s*#{Regexp.escape class_name}\s*,
                                   \s*"#{Regexp.escape new_name}"\s*,
                                   \s*"#{Regexp.escape old_name}"\s*\);%xm

    new_comment($1 || '', @top_level, :c)
  end

  ##
  # Finds a comment for rb_define_attr, rb_attr or Document-attr.
  #
  # +var_name+ is the C class variable the attribute is defined on.
  # +attr_name+ is the attribute's name.
  #
  # +read+ and +write+ are the read/write flags ('1' or '0').  Either both or
  # neither must be provided.

  def find_attr_comment var_name, attr_name, read = nil, write = nil
    attr_name = Regexp.escape attr_name

    rw = if read and write then
           /\s*#{read}\s*,\s*#{write}\s*/xm
         else
           /.*?/m
         end

    comment = if @content =~ %r%((?>/\*.*?\*/\s+))
                                rb_define_attr\((?:\s*#{var_name},)?\s*
                                                "#{attr_name}"\s*,
                                                #{rw}\)\s*;%xm then
                $1
              elsif @content =~ %r%((?>/\*.*?\*/\s+))
                                   rb_attr\(\s*#{var_name}\s*,
                                            \s*#{attr_name}\s*,
                                            #{rw},.*?\)\s*;%xm then
                $1
              elsif @content =~ %r%(/\*.*?(?:\s*\*\s*)?)
                                   Document-attr:\s#{attr_name}\s*?\n
                                   ((?>(.|\n)*?\*/))%x then
                "#{$1}\n#{$2}"
              else
                ''
              end

    new_comment comment, @top_level, :c
  end

  ##
  # Generate a Ruby-method table

  def gen_body_table file_content
    table = {}
    file_content.scan(%r{
      ((?>/\*.*?\*/\s*)?)
      ((?:(?:\w+)\s+)?
        (?:intern\s+)?VALUE\s+(\w+)
        \s*(?:\([^)]*\))(?:[^\);]|$))
    | ((?>/\*.*?\*/\s*))^\s*(\#\s*define\s+(\w+)\s+(\w+))
    | ^\s*\#\s*define\s+(\w+)\s+(\w+)
    }xm) do
      case
      when $1
        table[$3] = [:func_def, $1, $2, $~.offset(2)] if !table[$3] || table[$3][0] != :func_def
      when $4
        table[$6] = [:macro_def, $4, $5, $~.offset(5), $7] if !table[$6] || table[$6][0] == :macro_alias
      when $8
        table[$8] ||= [:macro_alias, $9]
      end
    end
    table
  end

  ##
  # Find the C code corresponding to a Ruby method

  def find_body class_name, meth_name, meth_obj, file_content, quiet = false
    if file_content
      @body_table ||= {}
      @body_table[file_content] ||= gen_body_table file_content
      type, *args = @body_table[file_content][meth_name]
    end

    case type
    when :func_def
      comment = new_comment args[0], @top_level, :c
      body = args[1]
      offset, = args[2]

      comment.remove_private if comment

      # try to find the whole body
      body = $& if /#{Regexp.escape body}[^(]*?\{.*?^\}/m =~ file_content

      # The comment block may have been overridden with a 'Document-method'
      # block. This happens in the interpreter when multiple methods are
      # vectored through to the same C method but those methods are logically
      # distinct (for example Kernel.hash and Kernel.object_id share the same
      # implementation

      override_comment = find_override_comment class_name, meth_obj
      comment = override_comment if override_comment

      comment.normalize
      find_modifiers comment, meth_obj if comment

      #meth_obj.params = params
      meth_obj.start_collecting_tokens
      tk = { :line_no => 1, :char_no => 1, :text => body }
      meth_obj.add_token tk
      meth_obj.comment = comment
      meth_obj.line    = file_content[0, offset].count("\n") + 1

      body
    when :macro_def
      comment = new_comment args[0], @top_level, :c
      body = args[1]
      offset, = args[2]

      find_body class_name, args[3], meth_obj, file_content, true

      comment.normalize
      find_modifiers comment, meth_obj

      meth_obj.start_collecting_tokens
      tk = { :line_no => 1, :char_no => 1, :text => body }
      meth_obj.add_token tk
      meth_obj.comment = comment
      meth_obj.line    = file_content[0, offset].count("\n") + 1

      body
    when :macro_alias
      # with no comment we hope the aliased definition has it and use it's
      # definition

      body = find_body(class_name, args[0], meth_obj, file_content, true)

      return body if body

      @options.warn "No definition for #{meth_name}"
      false
    else # No body, but might still have an override comment
      comment = find_override_comment class_name, meth_obj

      if comment then
        comment.normalize
        find_modifiers comment, meth_obj
        meth_obj.comment = comment

        ''
      else
        @options.warn "No definition for #{meth_name}"
        false
      end
    end
  end

  ##
  # Finds a RDoc::NormalClass or RDoc::NormalModule for +raw_name+

  def find_class(raw_name, name)
    unless @classes[raw_name]
      if raw_name =~ /^rb_m/
        container = @top_level.add_module RDoc::NormalModule, name
      else
        container = @top_level.add_class RDoc::NormalClass, name
      end

      container.record_location @top_level
      @classes[raw_name] = container
    end
    @classes[raw_name]
  end

  ##
  # Look for class or module documentation above Init_+class_name+(void),
  # in a Document-class +class_name+ (or module) comment or above an
  # rb_define_class (or module).  If a comment is supplied above a matching
  # Init_ and a rb_define_class the Init_ comment is used.
  #
  #   /*
  #    * This is a comment for Foo
  #    */
  #   Init_Foo(void) {
  #       VALUE cFoo = rb_define_class("Foo", rb_cObject);
  #   }
  #
  #   /*
  #    * Document-class: Foo
  #    * This is a comment for Foo
  #    */
  #   Init_foo(void) {
  #       VALUE cFoo = rb_define_class("Foo", rb_cObject);
  #   }
  #
  #   /*
  #    * This is a comment for Foo
  #    */
  #   VALUE cFoo = rb_define_class("Foo", rb_cObject);

  def find_class_comment class_name, class_mod
    comment = nil

    if @content =~ %r%
        ((?>/\*.*?\*/\s+))
        (static\s+)?
        void\s+
        Init_#{class_name}\s*(?:_\(\s*)?\(\s*(?:void\s*)?\)%xmi then
      comment = $1.sub(%r%Document-(?:class|module):\s+#{class_name}%, '')
    elsif @content =~ %r%Document-(?:class|module):\s+#{class_name}\s*?
                         (?:<\s+[:,\w]+)?\n((?>.*?\*/))%xm then
      comment = "/*\n#{$1}"
    elsif @content =~ %r%((?>/\*.*?\*/\s+))
                         ([\w\.\s]+\s* = \s+)?rb_define_(class|module)[\t (]*?"(#{class_name})"%xm then
      comment = $1
    elsif @content =~ %r%((?>/\*.*?\*/\s+))
                         ([\w\. \t]+ = \s+)?rb_define_(class|module)_under[\t\w, (]*?"(#{class_name.split('::').last})"%xm then
      comment = $1
    else
      comment = ''
    end

    comment = new_comment comment, @top_level, :c
    comment.normalize

    look_for_directives_in class_mod, comment

    class_mod.add_comment comment, @top_level
  end

  ##
  # Generate a const table

  def gen_const_table file_content
    table = {}
    @content.scan(%r{
      ((?>^\s*/\*.*?\*/\s+))
        rb_define_(\w+)\((?:\s*(?:\w+),)?\s*
                           "(\w+)"\s*,
                           .*?\)\s*;
    | Document-(?:const|global|variable):\s
        ((?:\w+::)*\w+)
        \s*?\n((?>.*?\*/))
    }mxi) do
      case
      when $1 then table[[$2, $3]] = $1
      when $4 then table[$4] = "/*\n" + $5
      end
    end
    table
  end

  ##
  # Finds a comment matching +type+ and +const_name+ either above the
  # comment or in the matching Document- section.

  def find_const_comment(type, const_name, class_name = nil)
    @const_table ||= {}
    @const_table[@content] ||= gen_const_table @content
    table = @const_table[@content]

    comment =
      table[[type, const_name]] ||
      (class_name && table[class_name + "::" + const_name]) ||
      table[const_name] ||
      ''

    new_comment comment, @top_level, :c
  end

  ##
  # Handles modifiers in +comment+ and updates +meth_obj+ as appropriate.

  def find_modifiers comment, meth_obj
    comment.normalize
    comment.extract_call_seq meth_obj

    look_for_directives_in meth_obj, comment
  end

  ##
  # Finds a <tt>Document-method</tt> override for +meth_obj+ on +class_name+

  def find_override_comment class_name, meth_obj
    name = Regexp.escape meth_obj.name
    prefix = Regexp.escape meth_obj.name_prefix

    comment = if @content =~ %r%Document-method:
                                \s+#{class_name}#{prefix}#{name}
                                \s*?\n((?>.*?\*/))%xm then
                "/*#{$1}"
              elsif @content =~ %r%Document-method:
                                   \s#{name}\s*?\n((?>.*?\*/))%xm then
                "/*#{$1}"
              end

    return unless comment

    new_comment comment, @top_level, :c
  end

  ##
  # Creates a new RDoc::Attr +attr_name+ on class +var_name+ that is either
  # +read+, +write+ or both

  def handle_attr(var_name, attr_name, read, write)
    rw = ''
    rw += 'R' if '1' == read
    rw += 'W' if '1' == write

    class_name = @known_classes[var_name]

    return unless class_name

    class_obj = find_class var_name, class_name

    return unless class_obj

    comment = find_attr_comment var_name, attr_name
    comment.normalize

    name = attr_name.gsub(/rb_intern(?:_const)?\("([^"]+)"\)/, '\1')

    attr = RDoc::Attr.new '', name, rw, comment

    attr.record_location @top_level
    class_obj.add_attribute attr
    @stats.add_attribute attr
  end

  ##
  # Creates a new RDoc::NormalClass or RDoc::NormalModule based on +type+
  # named +class_name+ in +parent+ which was assigned to the C +var_name+.

  def handle_class_module(var_name, type, class_name, parent, in_module)
    parent_name = @known_classes[parent] || parent

    if in_module then
      enclosure = @classes[in_module] || @store.find_c_enclosure(in_module)

      if enclosure.nil? and enclosure = @known_classes[in_module] then
        enc_type = /^rb_m/ =~ in_module ? :module : :class
        handle_class_module in_module, enc_type, enclosure, nil, nil
        enclosure = @classes[in_module]
      end

      unless enclosure then
        @enclosure_dependencies[in_module] << var_name
        @missing_dependencies[var_name] =
          [var_name, type, class_name, parent, in_module]

        return
      end
    else
      enclosure = @top_level
    end

    if type == :class then
      full_name = if RDoc::ClassModule === enclosure then
                    enclosure.full_name + "::#{class_name}"
                  else
                    class_name
                  end

      if @content =~ %r%Document-class:\s+#{full_name}\s*<\s+([:,\w]+)% then
        parent_name = $1
      end

      cm = enclosure.add_class RDoc::NormalClass, class_name, parent_name
    else
      cm = enclosure.add_module RDoc::NormalModule, class_name
    end

    cm.record_location enclosure.top_level

    find_class_comment cm.full_name, cm

    case cm
    when RDoc::NormalClass
      @stats.add_class cm
    when RDoc::NormalModule
      @stats.add_module cm
    end

    @classes[var_name] = cm
    @known_classes[var_name] = cm.full_name
    @store.add_c_enclosure var_name, cm
  end

  ##
  # Adds constants.  By providing some_value: at the start of the comment you
  # can override the C value of the comment to give a friendly definition.
  #
  #   /* 300: The perfect score in bowling */
  #   rb_define_const(cFoo, "PERFECT", INT2FIX(300));
  #
  # Will override <tt>INT2FIX(300)</tt> with the value +300+ in the output
  # RDoc.  Values may include quotes and escaped colons (\:).

  def handle_constants(type, var_name, const_name, definition)
    class_name = @known_classes[var_name]

    return unless class_name

    class_obj = find_class var_name, class_name

    unless class_obj then
      @options.warn 'Enclosing class or module %p is not known' % [const_name]
      return
    end

    comment = find_const_comment type, const_name, class_name
    comment.normalize

    # In the case of rb_define_const, the definition and comment are in
    # "/* definition: comment */" form.  The literal ':' and '\' characters
    # can be escaped with a backslash.
    if type.downcase == 'const' then
      no_match, new_definition, new_comment = comment.text.split(/(\A.*):/)

      if no_match and no_match.empty? then
        if new_definition.empty? then # Default to literal C definition
          new_definition = definition
        else
          new_definition = new_definition.gsub("\:", ":")
          new_definition = new_definition.gsub("\\", '\\')
        end

        new_definition.sub!(/\A(\s+)/, '')

        new_comment = "#{$1}#{new_comment.lstrip}"

        new_comment = self.new_comment(new_comment, @top_level, :c)

        con = RDoc::Constant.new const_name, new_definition, new_comment
      else
        con = RDoc::Constant.new const_name, definition, comment
      end
    else
      con = RDoc::Constant.new const_name, definition, comment
    end

    con.record_location @top_level
    @stats.add_constant con
    class_obj.add_constant con
  end

  ##
  # Removes #ifdefs that would otherwise confuse us

  def handle_ifdefs_in(body)
    body.gsub(/^#ifdef HAVE_PROTOTYPES.*?#else.*?\n(.*?)#endif.*?\n/m, '\1')
  end

  ##
  # Adds an RDoc::AnyMethod +meth_name+ defined on a class or module assigned
  # to +var_name+.  +type+ is the type of method definition function used.
  # +singleton_method+ and +module_function+ create a singleton method.

  def handle_method(type, var_name, meth_name, function, param_count,
                    source_file = nil)
    class_name = @known_classes[var_name]
    singleton  = @singleton_classes.key? var_name

    @methods[var_name][function] << meth_name

    return unless class_name

    class_obj = find_class var_name, class_name

    if existing_method = class_obj.method_list.find { |m| m.c_function == function }
      add_alias(var_name, class_obj, existing_method.name, meth_name, existing_method.comment)
    end

    if class_obj then
      if meth_name == 'initialize' then
        meth_name = 'new'
        singleton = true
        type = 'method' # force public
      end

      meth_obj = RDoc::AnyMethod.new '', meth_name
      meth_obj.c_function = function
      meth_obj.singleton =
        singleton || %w[singleton_method module_function].include?(type)

      p_count = Integer(param_count) rescue -1

      if source_file then
        file_name = File.join @file_dir, source_file

        if File.exist? file_name then
          file_content = File.read file_name
        else
          @options.warn "unknown source #{source_file} for #{meth_name} in #{@file_name}"
        end
      else
        file_content = @content
      end

      body = find_body class_name, function, meth_obj, file_content

      if body and meth_obj.document_self then
        meth_obj.params = if p_count < -1 then # -2 is Array
                            '(*args)'
                          elsif p_count == -1 then # argc, argv
                            rb_scan_args body
                          else
                            "(#{(1..p_count).map { |i| "p#{i}" }.join ', '})"
                          end


        meth_obj.record_location @top_level

        if meth_obj.section_title
          class_obj.temporary_section = class_obj.add_section(meth_obj.section_title)
        end
        class_obj.add_method meth_obj

        @stats.add_method meth_obj
        meth_obj.visibility = :private if 'private_method' == type
      end
    end
  end

  ##
  # Registers a singleton class +sclass_var+ as a singleton of +class_var+

  def handle_singleton sclass_var, class_var
    class_name = @known_classes[class_var]

    @known_classes[sclass_var]     = class_name
    @singleton_classes[sclass_var] = class_name
  end

  ##
  # Normalizes tabs in +body+

  def handle_tab_width(body)
    if /\t/ =~ body
      tab_width = @options.tab_width
      body.split(/\n/).map do |line|
        1 while line.gsub!(/\t+/) do
          ' ' * (tab_width * $&.length - $`.length % tab_width)
        end && $~
        line
      end.join "\n"
    else
      body
    end
  end

  ##
  # Loads the variable map with the given +name+ from the RDoc::Store, if
  # present.

  def load_variable_map map_name
    return {} unless files = @store.cache[map_name]
    return {} unless name_map = files[@file_name]

    class_map = {}

    name_map.each do |variable, name|
      next unless mod = @store.find_class_or_module(name)

      class_map[variable] = if map_name == :c_class_variables then
                              mod
                            else
                              name
                            end
      @known_classes[variable] = name
    end

    class_map
  end

  ##
  # Look for directives in a normal comment block:
  #
  #   /*
  #    * :title: My Awesome Project
  #    */
  #
  # This method modifies the +comment+

  def look_for_directives_in context, comment
    @preprocess.handle comment, context do |directive, param|
      case directive
      when 'main' then
        @options.main_page = param
        ''
      when 'title' then
        @options.default_title = param if @options.respond_to? :default_title=
        ''
      end
    end

    comment
  end

  ##
  # Extracts parameters from the +method_body+ and returns a method
  # parameter string.  Follows 1.9.3dev's scan-arg-spec, see README.EXT

  def rb_scan_args method_body
    method_body =~ /rb_scan_args\((.*?)\)/m
    return '(*args)' unless $1

    $1.split(/,/)[2] =~ /"(.*?)"/ # format argument
    format = $1.split(//)

    lead = opt = trail = 0

    if format.first =~ /\d/ then
      lead = $&.to_i
      format.shift
      if format.first =~ /\d/ then
        opt = $&.to_i
        format.shift
        if format.first =~ /\d/ then
          trail = $&.to_i
          format.shift
          block_arg = true
        end
      end
    end

    if format.first == '*' and not block_arg then
      var = true
      format.shift
      if format.first =~ /\d/ then
        trail = $&.to_i
        format.shift
      end
    end

    if format.first == ':' then
      hash = true
      format.shift
    end

    if format.first == '&' then
      block = true
      format.shift
    end

    # if the format string is not empty there's a bug in the C code, ignore it

    args = []
    position = 1

    (1...(position + lead)).each do |index|
      args << "p#{index}"
    end

    position += lead

    (position...(position + opt)).each do |index|
      args << "p#{index} = v#{index}"
    end

    position += opt

    if var then
      args << '*args'
      position += 1
    end

    (position...(position + trail)).each do |index|
      args << "p#{index}"
    end

    position += trail

    if hash then
      args << "p#{position} = {}"
    end

    args << '&block' if block

    "(#{args.join ', '})"
  end

  ##
  # Removes lines that are commented out that might otherwise get picked up
  # when scanning for classes and methods

  def remove_commented_out_lines
    @content = @content.gsub(%r%//.*rb_define_%, '//')
  end

  ##
  # Extracts the classes, modules, methods, attributes, constants and aliases
  # from a C file and returns an RDoc::TopLevel for this file

  def scan
    remove_commented_out_lines

    do_classes_and_modules
    do_missing

    do_constants
    do_methods
    do_includes
    do_aliases
    do_attrs

    @store.add_c_variables self

    @top_level
  end

  def new_comment text = nil, location = nil, language = nil
    RDoc::Comment.new(text, location, language).tap do |comment|
      comment.format = @markup
    end
  end
end