summaryrefslogtreecommitdiffstats
path: root/contrib/texinfo/info/nodes.c
blob: 7f0bf0f343bd3dd03b8e9d6cd978d5b69573da5e (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
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
/* nodes.c -- how to get an Info file and node.
   $Id: nodes.c,v 1.15 2000/11/11 00:40:37 karl Exp $

   Copyright (C) 1993, 98, 99, 2000 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

   Written by Brian Fox (bfox@ai.mit.edu). */

#include "info.h"

#include "nodes.h"
#include "search.h"
#include "filesys.h"
#include "info-utils.h"

#if defined (HANDLE_MAN_PAGES)
#  include "man.h"
#endif /* HANDLE_MAN_PAGES */

static void forget_info_file (), remember_info_file ();
static void free_file_buffer_tags (), free_info_tag ();
static void get_nodes_of_tags_table (), get_nodes_of_info_file ();
static void get_tags_of_indirect_tags_table ();
static void info_reload_file_buffer_contents ();
static char *adjust_nodestart ();
static FILE_BUFFER *info_load_file_internal (), *info_find_file_internal ();
static NODE *info_node_of_file_buffer_tags ();

static long get_node_length ();

/* Magic number that RMS used to decide how much a tags table pointer could
   be off by.  I feel that it should be much smaller, like 4.  */
#define DEFAULT_INFO_FUDGE 1000

/* Passed to *_internal functions.  INFO_GET_TAGS says to do what is
   neccessary to fill in the nodes or tags arrays in FILE_BUFFER. */
#define INFO_NO_TAGS  0
#define INFO_GET_TAGS 1

/* Global variables.  */

/* When non-zero, this is a string describing the recent file error. */
char *info_recent_file_error = NULL;

/* The list of already loaded nodes. */
FILE_BUFFER **info_loaded_files = NULL;

/* The number of slots currently allocated to LOADED_FILES. */
int info_loaded_files_slots = 0;

/* Public functions for node manipulation.  */

/* Used to build `dir' menu from `localdir' files found in INFOPATH. */
extern void maybe_build_dir_node ();

/* Return a pointer to a NODE structure for the Info node (FILENAME)NODENAME.
   If FILENAME is NULL, `dir' is used.
   IF NODENAME is NULL, `Top' is used.
   If the node cannot be found, return NULL. */
NODE *
info_get_node (filename, nodename)
     char *filename, *nodename;
{
  NODE *node;
  FILE_BUFFER *file_buffer = NULL;

  info_recent_file_error = NULL;
  info_parse_node (nodename, DONT_SKIP_NEWLINES);
  nodename = NULL;

  if (info_parsed_filename)
    filename = info_parsed_filename;

  if (info_parsed_nodename)
    nodename = info_parsed_nodename;

  /* If FILENAME is not specified, it defaults to "dir". */
  if (!filename)
    filename = "dir";

  /* If the file to be looked up is "dir", build the contents from all of
     the "dir"s and "localdir"s found in INFOPATH. */
  if (is_dir_name (filename))
    maybe_build_dir_node (filename);

  /* Find the correct info file, or give up.  */
  file_buffer = info_find_file (filename);
  if (!file_buffer)
    {
      if (filesys_error_number)
        info_recent_file_error =
          filesys_error_string (filename, filesys_error_number);
      return NULL;
    }

  /* Look for the node.  */
  node = info_get_node_of_file_buffer (nodename, file_buffer);

  /* If the node not found was "Top", try again with different case.  */
  if (!node && (nodename == NULL || strcasecmp (nodename, "Top") == 0))
    {
      node = info_get_node_of_file_buffer ("Top", file_buffer);
      if (!node)
        node = info_get_node_of_file_buffer ("top", file_buffer);
      if (!node)
        node = info_get_node_of_file_buffer ("TOP", file_buffer);
    }

  return node;
}

/* Return a pointer to a NODE structure for the Info node NODENAME in
   FILE_BUFFER.  NODENAME can be passed as NULL, in which case the
   nodename of "Top" is used.  If the node cannot be found, return a
   NULL pointer. */
NODE *
info_get_node_of_file_buffer (nodename, file_buffer)
     char *nodename;
     FILE_BUFFER *file_buffer;
{
  NODE *node = NULL;

  /* If we are unable to find the file, we have to give up.  There isn't
     anything else we can do. */
  if (!file_buffer)
    return NULL;

  /* If the file buffer was gc'ed, reload the contents now. */
  if (!file_buffer->contents)
    info_reload_file_buffer_contents (file_buffer);

  /* If NODENAME is not specified, it defaults to "Top". */
  if (!nodename)
    nodename = "Top";

  /* If the name of the node that we wish to find is exactly "*", then the
     node body is the contents of the entire file.  Create and return such
     a node. */
  if (strcmp (nodename, "*") == 0)
    {
      node = (NODE *)xmalloc (sizeof (NODE));
      node->filename = file_buffer->fullpath;
      node->parent   = NULL;
      node->nodename = xstrdup ("*");
      node->contents = file_buffer->contents;
      node->nodelen = file_buffer->filesize;
      node->flags = 0;
      node->display_pos = 0;
    }
#if defined (HANDLE_MAN_PAGES)
  /* If the file buffer is the magic one associated with manpages, call
     the manpage node finding function instead. */
  else if (file_buffer->flags & N_IsManPage)
    {
        node = get_manpage_node (file_buffer, nodename);
    }
#endif /* HANDLE_MAN_PAGES */
  /* If this is the "main" info file, it might contain a tags table.  Search
     the tags table for an entry which matches the node that we want.  If
     there is a tags table, get the file which contains this node, but don't
     bother building a node list for it. */
  else if (file_buffer->tags)
    {
      node = info_node_of_file_buffer_tags (file_buffer, nodename);
    }

  /* Return the results of our node search. */
  return node;
}

/* Locate the file named by FILENAME, and return the information structure
   describing this file.  The file may appear in our list of loaded files
   already, or it may not.  If it does not already appear, find the file,
   and add it to the list of loaded files.  If the file cannot be found,
   return a NULL FILE_BUFFER *. */
FILE_BUFFER *
info_find_file (filename)
     char *filename;
{
  return info_find_file_internal (filename, INFO_GET_TAGS);
}

/* Load the info file FILENAME, remembering information about it in a
   file buffer. */
FILE_BUFFER *
info_load_file (filename)
     char *filename;
{
  return info_load_file_internal (filename, INFO_GET_TAGS);
}


/* Private functions implementation.  */

/* The workhorse for info_find_file ().  Non-zero 2nd argument says to
   try to build a tags table (or otherwise glean the nodes) for this
   file once found.  By default, we build the tags table, but when this
   function is called by info_get_node () when we already have a valid
   tags table describing the nodes, it is unnecessary. */
static FILE_BUFFER *
info_find_file_internal (filename, get_tags)
     char *filename;
     int get_tags;
{
  int i;
  FILE_BUFFER *file_buffer;

  /* First try to find the file in our list of already loaded files. */
  if (info_loaded_files)
    {
      for (i = 0; (file_buffer = info_loaded_files[i]); i++)
        if ((FILENAME_CMP (filename, file_buffer->filename) == 0)
            || (FILENAME_CMP (filename, file_buffer->fullpath) == 0)
            || (!IS_ABSOLUTE (filename)
                && FILENAME_CMP (filename,
                                filename_non_directory (file_buffer->fullpath))
                    == 0))
          {
            struct stat new_info, *old_info;

            /* This file is loaded.  If the filename that we want is
               specifically "dir", then simply return the file buffer. */
            if (is_dir_name (filename_non_directory (filename)))
              return file_buffer;

#if defined (HANDLE_MAN_PAGES)
            /* Do the same for the magic MANPAGE file. */
            if (file_buffer->flags & N_IsManPage)
              return file_buffer;
#endif /* HANDLE_MAN_PAGES */

            /* The file appears to be already loaded, and is not "dir".  Check
               to see if it's changed since the last time it was loaded.  */
            if (stat (file_buffer->fullpath, &new_info) == -1)
              {
                filesys_error_number = errno;
                return NULL;
              }

            old_info = &file_buffer->finfo;

            if (new_info.st_size != old_info->st_size
                || new_info.st_mtime != old_info->st_mtime)
              {
                /* The file has changed.  Forget that we ever had loaded it
                   in the first place. */
                forget_info_file (filename);
                break;
              }
            else
              {
                /* The info file exists, and has not changed since the last
                   time it was loaded.  If the caller requested a nodes list
                   for this file, and there isn't one here, build the nodes
                   for this file_buffer.  In any case, return the file_buffer
                   object. */
                if (!file_buffer->contents)
                  {
                    /* The file's contents have been gc'ed.  Reload it.  */
                    info_reload_file_buffer_contents (file_buffer);
                    if (!file_buffer->contents)
                      return NULL;
                  }

                if (get_tags && !file_buffer->tags)
                  build_tags_and_nodes (file_buffer);

                return file_buffer;
              }
          }
    }

  /* The file wasn't loaded.  Try to load it now. */
#if defined (HANDLE_MAN_PAGES)
  /* If the name of the file that we want is our special file buffer for
     Unix manual pages, then create the file buffer, and return it now. */
  if (strcasecmp (filename, MANPAGE_FILE_BUFFER_NAME) == 0)
    file_buffer = create_manpage_file_buffer ();
  else
#endif /* HANDLE_MAN_PAGES */
    file_buffer = info_load_file_internal (filename, get_tags);

  /* If the file was loaded, remember the name under which it was found. */
  if (file_buffer)
    remember_info_file (file_buffer);

  return file_buffer;
}

/* The workhorse function for info_load_file ().  Non-zero second argument
   says to build a list of tags (or nodes) for this file.  This is the
   default behaviour when info_load_file () is called, but it is not
   necessary when loading a subfile for which we already have tags. */
static FILE_BUFFER *
info_load_file_internal (filename, get_tags)
     char *filename;
     int get_tags;
{
  char *fullpath, *contents;
  long filesize;
  struct stat finfo;
  int retcode, compressed;
  FILE_BUFFER *file_buffer = NULL;

  /* Get the full pathname of this file, as known by the info system.
     That is to say, search along INFOPATH and expand tildes, etc. */
  fullpath = info_find_fullpath (filename);

  /* Did we actually find the file? */
  retcode = stat (fullpath, &finfo);

  /* If the file referenced by the name returned from info_find_fullpath ()
     doesn't exist, then try again with the last part of the filename
     appearing in lowercase. */
  /* This is probably not needed at all on those systems which define
     FILENAME_CMP to be strcasecmp.  But let's do it anyway, lest some
     network redirector supports case sensitivity.  */
  if (retcode < 0)
    {
      char *lowered_name;
      char *basename;

      lowered_name = xstrdup (filename);
      basename = filename_non_directory (lowered_name);

      while (*basename)
        {
          if (isupper (*basename))
            *basename = tolower (*basename);

          basename++;
        }

      fullpath = info_find_fullpath (lowered_name);
      free (lowered_name);

      retcode = stat (fullpath, &finfo);
    }

  /* If the file wasn't found, give up, returning a NULL pointer. */
  if (retcode < 0)
    {
      filesys_error_number = errno;
      return NULL;
    }

  /* Otherwise, try to load the file. */
  contents = filesys_read_info_file (fullpath, &filesize, &finfo, &compressed);

  if (!contents)
    return NULL;

  /* The file was found, and can be read.  Allocate FILE_BUFFER and fill
     in the various members. */
  file_buffer = make_file_buffer ();
  file_buffer->filename = xstrdup (filename);
  file_buffer->fullpath = xstrdup (fullpath);
  file_buffer->finfo = finfo;
  file_buffer->filesize = filesize;
  file_buffer->contents = contents;
  if (compressed)
    file_buffer->flags |= N_IsCompressed;

  /* If requested, build the tags and nodes for this file buffer. */
  if (get_tags)
    build_tags_and_nodes (file_buffer);

  return file_buffer;
}

/* Grovel FILE_BUFFER->contents finding tags and nodes, and filling in the
   various slots.  This can also be used to rebuild a tag or node table. */
void
build_tags_and_nodes (file_buffer)
     FILE_BUFFER *file_buffer;
{
  SEARCH_BINDING binding;
  long position;

  free_file_buffer_tags (file_buffer);
  file_buffer->flags &= ~N_HasTagsTable;

  /* See if there is a tags table in this info file. */
  binding.buffer = file_buffer->contents;
  binding.start = file_buffer->filesize;
  binding.end = binding.start - 1000;
  if (binding.end < 0)
    binding.end = 0;
  binding.flags = S_FoldCase;

  position = search_backward (TAGS_TABLE_END_LABEL, &binding);

  /* If there is a tag table, find the start of it, and grovel over it
     extracting tag information. */
  if (position != -1)
    while (1)
      {
        long tags_table_begin, tags_table_end;

        binding.end = position;
        binding.start = binding.end - 5 - strlen (TAGS_TABLE_END_LABEL);
        if (binding.start < 0)
          binding.start = 0;

        position = find_node_separator (&binding);

        /* For this test, (and all others here) failure indicates a bogus
           tags table.  Grovel the file. */
        if (position == -1)
          break;

        /* Remember the end of the tags table. */
        binding.start = position;
        tags_table_end = binding.start;
        binding.end = 0;

        /* Locate the start of the tags table. */
        position = search_backward (TAGS_TABLE_BEG_LABEL, &binding);

        if (position == -1)
          break;

        binding.end = position;
        binding.start = binding.end - 5 - strlen (TAGS_TABLE_BEG_LABEL);
        position = find_node_separator (&binding);

        if (position == -1)
          break;

        /* The file contains a valid tags table.  Fill the FILE_BUFFER's
           tags member. */
        file_buffer->flags |= N_HasTagsTable;
        tags_table_begin = position;

        /* If this isn't an indirect tags table, just remember the nodes
           described locally in this tags table.  Note that binding.end
           is pointing to just after the beginning label. */
        binding.start = binding.end;
        binding.end = file_buffer->filesize;

        if (!looking_at (TAGS_TABLE_IS_INDIRECT_LABEL, &binding))
          {
            binding.start = tags_table_begin;
            binding.end = tags_table_end;
            get_nodes_of_tags_table (file_buffer, &binding);
            return;
          }
        else
          {
            /* This is an indirect tags table.  Build TAGS member. */
            SEARCH_BINDING indirect;

            indirect.start = tags_table_begin;
            indirect.end = 0;
            indirect.buffer = binding.buffer;
            indirect.flags = S_FoldCase;

            position = search_backward (INDIRECT_TAGS_TABLE_LABEL, &indirect);

            if (position == -1)
              {
                /* This file is malformed.  Give up. */
                return;
              }

            indirect.start = position;
            indirect.end = tags_table_begin;
            binding.start = tags_table_begin;
            binding.end = tags_table_end;
            get_tags_of_indirect_tags_table (file_buffer, &indirect, &binding);
            return;
          }
      }

  /* This file doesn't contain any kind of tags table.  Grovel the
     file and build node entries for it. */
  get_nodes_of_info_file (file_buffer);
}

/* Search through FILE_BUFFER->contents building an array of TAG *,
   one entry per each node present in the file.  Store the tags in
   FILE_BUFFER->tags, and the number of allocated slots in
   FILE_BUFFER->tags_slots. */
static void
get_nodes_of_info_file (file_buffer)
     FILE_BUFFER *file_buffer;
{
  long nodestart;
  int tags_index = 0;
  SEARCH_BINDING binding;

  binding.buffer = file_buffer->contents;
  binding.start = 0;
  binding.end = file_buffer->filesize;
  binding.flags = S_FoldCase;

  while ((nodestart = find_node_separator (&binding)) != -1)
    {
      int start, end;
      char *nodeline;
      TAG *entry;
      int anchor = 0;

      /* Skip past the characters just found. */
      binding.start = nodestart;
      binding.start += skip_node_separator (binding.buffer + binding.start);

      /* Move to the start of the line defining the node. */
      nodeline = binding.buffer + binding.start;

      /* Find "Node:" */
      start = string_in_line (INFO_NODE_LABEL, nodeline);
      /* No Node:.  Maybe it's a Ref:.  */
      if (start == -1)
        {
          start = string_in_line (INFO_REF_LABEL, nodeline);
          if (start != -1)
            anchor = 1;
        }

      /* If not there, this is not the start of a node. */
      if (start == -1)
        continue;

      /* Find the start of the nodename. */
      start += skip_whitespace (nodeline + start);

      /* Find the end of the nodename. */
      end = start +
        skip_node_characters (nodeline + start, DONT_SKIP_NEWLINES);

      /* Okay, we have isolated the node name, and we know where the
         node starts.  Remember this information. */
      entry = xmalloc (sizeof (TAG));
      entry->nodename = xmalloc (1 + (end - start));
      strncpy (entry->nodename, nodeline + start, end - start);
      entry->nodename[end - start] = 0;
      entry->nodestart = nodestart;
      if (anchor)
        entry->nodelen = 0;
      else
        {
          SEARCH_BINDING node_body;

          node_body.buffer = binding.buffer + binding.start;
          node_body.start = 0;
          node_body.end = binding.end - binding.start;
          node_body.flags = S_FoldCase;
          entry->nodelen = get_node_length (&node_body);
        }

      entry->filename = file_buffer->fullpath;

      /* Add this tag to the array of tag structures in this FILE_BUFFER. */
      add_pointer_to_array (entry, tags_index, file_buffer->tags,
                            file_buffer->tags_slots, 100, TAG *);
    }
}

/* Return the length of the node which starts at BINDING. */
static long
get_node_length (binding)
     SEARCH_BINDING *binding;
{
  int i;
  char *body;

  /* [A node] ends with either a ^_, a ^L, or end of file.  */
  for (i = binding->start, body = binding->buffer; i < binding->end; i++)
    {
      if (body[i] == INFO_FF || body[i] == INFO_COOKIE)
        break;
    }
  return i - binding->start;
}

/* Build and save the array of nodes in FILE_BUFFER by searching through the
   contents of BUFFER_BINDING for a tags table, and groveling the contents. */
static void
get_nodes_of_tags_table (file_buffer, buffer_binding)
     FILE_BUFFER *file_buffer;
     SEARCH_BINDING *buffer_binding;
{
  int name_offset;
  SEARCH_BINDING *search;
  long position;
  int tags_index = 0;

  search = copy_binding (buffer_binding);

  /* Find the start of the tags table. */
  position = find_tags_table (search);

  /* If none, we're all done. */
  if (position == -1)
    return;

  /* Move to one character before the start of the actual table. */
  search->start = position;
  search->start += skip_node_separator (search->buffer + search->start);
  search->start += strlen (TAGS_TABLE_BEG_LABEL);
  search->start--;

  /* The tag table consists of lines containing node names and positions.
     Do each line until we find one that doesn't contain a node name. */
  while ((position = search_forward ("\n", search)) != -1)
    {
      TAG *entry;
      char *nodedef;
      unsigned p;
      int anchor = 0;

      /* Prepare to skip this line. */
      search->start = position;
      search->start++;

      /* Skip past informative "(Indirect)" tags table line. */
      if (!tags_index && looking_at (TAGS_TABLE_IS_INDIRECT_LABEL, search))
        continue;

      /* Find the label preceding the node name. */
      name_offset =
        string_in_line (INFO_NODE_LABEL, search->buffer + search->start);

      /* If no node label, maybe it's an anchor.  */
      if (name_offset == -1)
        {
          name_offset = string_in_line (INFO_REF_LABEL,
                                        search->buffer + search->start);
          if (name_offset != -1)
            anchor = 1;
        }

      /* If not there, not a defining line, so we must be out of the
         tags table.  */
      if (name_offset == -1)
        break;

      entry = xmalloc (sizeof (TAG));

      /* Find the beginning of the node definition. */
      search->start += name_offset;
      nodedef = search->buffer + search->start;
      nodedef += skip_whitespace (nodedef);

      /* Move past the node's name in this tag to the TAGSEP character. */
      for (p = 0; nodedef[p] && nodedef[p] != INFO_TAGSEP; p++)
        ;
      if (nodedef[p] != INFO_TAGSEP)
        continue;

      entry->nodename = xmalloc (p + 1);
      strncpy (entry->nodename, nodedef, p);
      entry->nodename[p] = 0;
      p++;
      entry->nodestart = atol (nodedef + p);

      /* If a node, we don't know the length yet, but if it's an
         anchor, the length is 0. */
      entry->nodelen = anchor ? 0 : -1;

      /* The filename of this node is currently known as the same as the
         name of this file. */
      entry->filename = file_buffer->fullpath;

      /* Add this node structure to the array of node structures in this
         FILE_BUFFER. */
      add_pointer_to_array (entry, tags_index, file_buffer->tags,
                            file_buffer->tags_slots, 100, TAG *);
    }
  free (search);
}

/* A structure used only in `get_tags_of_indirect_tags_table' to hold onto
   an intermediate value. */
typedef struct {
  char *filename;
  long first_byte;
} SUBFILE;

/* Remember in FILE_BUFFER the nodenames, subfilenames, and offsets within the
   subfiles of every node which appears in TAGS_BINDING.  The 2nd argument is
   a binding surrounding the indirect files list. */
static void
get_tags_of_indirect_tags_table (file_buffer, indirect_binding, tags_binding)
     FILE_BUFFER *file_buffer;
     SEARCH_BINDING *indirect_binding, *tags_binding;
{
  int i;
  SUBFILE **subfiles = NULL;
  int subfiles_index = 0, subfiles_slots = 0;
  TAG *entry;

  /* First get the list of tags from the tags table.  Then lookup the
     associated file in the indirect list for each tag, and update it. */
  get_nodes_of_tags_table (file_buffer, tags_binding);

  /* We have the list of tags in file_buffer->tags.  Get the list of
     subfiles from the indirect table. */
  {
    char *start, *end, *line;
    SUBFILE *subfile;

    start = indirect_binding->buffer + indirect_binding->start;
    end = indirect_binding->buffer + indirect_binding->end;
    line = start;

    while (line < end)
      {
        int colon;

        colon = string_in_line (":", line);

        if (colon == -1)
          break;

        subfile = (SUBFILE *)xmalloc (sizeof (SUBFILE));
        subfile->filename = (char *)xmalloc (colon);
        strncpy (subfile->filename, line, colon - 1);
        subfile->filename[colon - 1] = 0;
        subfile->first_byte = (long) atol (line + colon);

        add_pointer_to_array
          (subfile, subfiles_index, subfiles, subfiles_slots, 10, SUBFILE *);

        while (*line++ != '\n');
      }
  }

  /* If we have successfully built the indirect files table, then
     merge the information in the two tables. */
  if (!subfiles)
    {
      free_file_buffer_tags (file_buffer);
      return;
    }
  else
    {
      int tags_index;
      long header_length;
      SEARCH_BINDING binding;

      /* Find the length of the header of the file containing the indirect
         tags table.  This header appears at the start of every file.  We
         want the absolute position of each node within each subfile, so
         we subtract the start of the containing subfile from the logical
         position of the node, and then add the length of the header in. */
      binding.buffer = file_buffer->contents;
      binding.start = 0;
      binding.end = file_buffer->filesize;
      binding.flags = S_FoldCase;

      header_length = find_node_separator (&binding);
      if (header_length == -1)
        header_length = 0;

      /* Build the file buffer's list of subfiles. */
      {
        char *containing_dir = xstrdup (file_buffer->fullpath);
        char *temp = filename_non_directory (containing_dir);
        int len_containing_dir;

        if (temp > containing_dir)
          {
            if (HAVE_DRIVE (file_buffer->fullpath) &&
                temp == containing_dir + 2)
              {
                /* Avoid converting "d:foo" into "d:/foo" below.  */
                *temp = '.';
                temp += 2;
              }
            temp[-1] = 0;
          }

        len_containing_dir = strlen (containing_dir);

        for (i = 0; subfiles[i]; i++);

        file_buffer->subfiles = (char **) xmalloc ((1 + i) * sizeof (char *));

        for (i = 0; subfiles[i]; i++)
          {
            char *fullpath;

            fullpath = (char *) xmalloc
              (2 + strlen (subfiles[i]->filename) + len_containing_dir);

            sprintf (fullpath, "%s/%s",
                     containing_dir, subfiles[i]->filename);

            file_buffer->subfiles[i] = fullpath;
          }
        file_buffer->subfiles[i] = NULL;
        free (containing_dir);
      }

      /* For each node in the file's tags table, remember the starting
         position. */
      for (tags_index = 0; (entry = file_buffer->tags[tags_index]);
           tags_index++)
        {
          for (i = 0;
               subfiles[i] && entry->nodestart >= subfiles[i]->first_byte;
               i++);

          /* If the Info file containing the indirect tags table is
             malformed, then give up. */
          if (!i)
            {
              /* The Info file containing the indirect tags table is
                 malformed.  Give up. */
              for (i = 0; subfiles[i]; i++)
                {
                  free (subfiles[i]->filename);
                  free (subfiles[i]);
                  free (file_buffer->subfiles[i]);
                }
              file_buffer->subfiles = NULL;
              free_file_buffer_tags (file_buffer);
              return;
            }

          /* SUBFILES[i] is the index of the first subfile whose logical
             first byte is greater than the logical offset of this node's
             starting position.  This means that the subfile directly
             preceding this one is the one containing the node. */

          entry->filename = file_buffer->subfiles[i - 1];
          entry->nodestart -= subfiles[i - 1]->first_byte;
          entry->nodestart += header_length;
        }

      /* We have successfully built the tags table.  Remember that it
         was indirect. */
      file_buffer->flags |= N_TagsIndirect;
    }

  /* Free the structures assigned to SUBFILES.  Free the names as well
     as the structures themselves, then finally, the array. */
  for (i = 0; subfiles[i]; i++)
    {
      free (subfiles[i]->filename);
      free (subfiles[i]);
    }
  free (subfiles);
}


/* Return the node that contains TAG in FILE_BUFFER, else
   (pathologically) NULL.  Called from info_node_of_file_buffer_tags.  */
static NODE *
find_node_of_anchor (file_buffer, tag)
     FILE_BUFFER *file_buffer;
     TAG *tag;
{
  int anchor_pos, node_pos;
  TAG *node_tag;
  NODE *node;
  
  /* Look through the tag list for the anchor.  */
  for (anchor_pos = 0; file_buffer->tags[anchor_pos]; anchor_pos++)
    {
      TAG *t = file_buffer->tags[anchor_pos];
      if (t->nodestart == tag->nodestart)
        break;        
    }
  
  /* Should not happen, because we should always find the anchor.  */
  if (!file_buffer->tags[anchor_pos])
    return NULL;
  
  /* We've found the anchor.  Look backwards in the tag table for the
     preceding node (we're assuming the tags are given in order),
     skipping over any preceding anchors.  */
  for (node_pos = anchor_pos - 1;
       node_pos >= 0 && file_buffer->tags[node_pos]->nodelen == 0;
       node_pos--)
    ;
  
  /* An info file with an anchor before any nodes is pathological, but
     it's possible, so don't crash.  */
  if (node_pos < 0)
    return NULL;
  
  /* We have the tag for the node that contained the anchor tag.  */
  node_tag = file_buffer->tags[node_pos]; 

  /* Look up the node name in the tag table to get the actual node.
     This is a recursive call, but it can't recurse again, because we
     call it with a real node.  */
  node = info_node_of_file_buffer_tags (file_buffer, node_tag->nodename);
  
  /* Start displaying the node at the anchor position.  */
  if (node)
    { /* The nodestart for real nodes is three characters before the `F'
         in the `File:' line (a newline, the CTRL-_, and another
         newline).  The nodestart for anchors is the actual position.
         But we offset by only 2, rather than 3, because if an anchor is
         at the beginning of a paragraph, it's nicer for it to end up on
         the beginning of the first line of the paragraph rather than
         the blank line before it.  (makeinfo has no way of knowing that
         a paragraph is going to start, so we can't fix it there.)  */
      node->display_pos = file_buffer->tags[anchor_pos]->nodestart
                          - (node_tag->nodestart + 2);

      /* Otherwise an anchor at the end of a node ends up displaying at
         the end of the last line of the node (way over on the right of
         the screen), which looks wrong.  */
      if (node->display_pos >= node->nodelen)
        node->display_pos = node->nodelen - 1;
      
      /* Don't search in the node for the xref text, it's not there.  */
      node->flags |= N_FromAnchor;
    }
  
  return node;
}


/* Return the node from FILE_BUFFER which matches NODENAME by searching
   the tags table in FILE_BUFFER, or NULL.  */
static NODE *
info_node_of_file_buffer_tags (file_buffer, nodename)
     FILE_BUFFER *file_buffer;
     char *nodename;
{
  TAG *tag;
  int i;

  /* If no tags at all (possibly a misformatted info file), quit.  */
  if (!file_buffer->tags) {
    return NULL;
  }
  
  for (i = 0; (tag = file_buffer->tags[i]); i++)    
    if (strcmp (nodename, tag->nodename) == 0)
      {
        FILE_BUFFER *subfile = info_find_file_internal (tag->filename,
                                                        INFO_NO_TAGS);
        if (!subfile)
          return NULL;

        if (!subfile->contents)
          {
            info_reload_file_buffer_contents (subfile);
            if (!subfile->contents)
              return NULL;
          }

        /* If we were able to find this file and load it, then return
           the node within it. */
        {
          NODE *node = xmalloc (sizeof (NODE));
          node->filename    = subfile->fullpath;
          node->parent      = NULL;
          node->nodename    = tag->nodename;
          node->contents    = subfile->contents + tag->nodestart;
          node->display_pos = 0;
          node->flags       = 0;

          if (file_buffer->flags & N_HasTagsTable)
            {
              node->flags |= N_HasTagsTable;

              if (file_buffer->flags & N_TagsIndirect)
                {
                  node->flags |= N_TagsIndirect;
                  node->parent = file_buffer->fullpath;
                }
            }

          if (subfile->flags & N_IsCompressed)
            node->flags |= N_IsCompressed;

          /* If TAG->nodelen hasn't been calculated yet, then we aren't
             in a position to trust the entry pointer.  Adjust things so
             that ENTRY->nodestart gets the exact address of the start of
             the node separator which starts this node, and NODE->contents
             gets the address of the line defining this node.  If we cannot
             do that, the node isn't really here. */
          if (tag->nodelen == -1)
            {
              int min, max;
              char *node_sep;
              SEARCH_BINDING node_body;
              char *buff_end;

              min = max = DEFAULT_INFO_FUDGE;

              if (tag->nodestart < DEFAULT_INFO_FUDGE)
                min = tag->nodestart;

              if (DEFAULT_INFO_FUDGE >
                  (subfile->filesize - tag->nodestart))
                max = subfile->filesize - tag->nodestart;

              /* NODE_SEP gets the address of the separator which defines
                 this node, or NULL if the node wasn't found.
                 NODE->contents is side-effected to point to right after
                 the separator. */
              node_sep = adjust_nodestart (node, min, max);
              if (node_sep == NULL)
                {
                  free (node);
                  return NULL;
                }
              /* Readjust tag->nodestart. */
              tag->nodestart = node_sep - subfile->contents;

              /* Calculate the length of the current node. */
              buff_end = subfile->contents + subfile->filesize;

              node_body.buffer = node->contents;
              node_body.start = 0;
              node_body.end = buff_end - node_body.buffer;
              node_body.flags = 0;
              tag->nodelen = get_node_length (&node_body);
              node->nodelen = tag->nodelen;
            }

          else if (tag->nodelen == 0) /* anchor, return containing node */
            {
              free (node);
              node = find_node_of_anchor (file_buffer, tag);
            }
            
          else
            {
              /* Since we know the length of this node, we have already
                 adjusted tag->nodestart to point to the exact start of
                 it.  Simply skip the node separator. */
              node->contents += skip_node_separator (node->contents);
              node->nodelen = tag->nodelen;
            }

          return node;
        }
      }

  /* There was a tag table for this file, and the node wasn't found.
     Return NULL, since this file doesn't contain the desired node. */
  return NULL;
}

/* Managing file_buffers, nodes, and tags.  */

/* Create a new, empty file buffer. */
FILE_BUFFER *
make_file_buffer ()
{
  FILE_BUFFER *file_buffer = xmalloc (sizeof (FILE_BUFFER));

  file_buffer->filename = file_buffer->fullpath = NULL;
  file_buffer->contents = NULL;
  file_buffer->tags = NULL;
  file_buffer->subfiles = NULL;
  file_buffer->tags_slots = 0;
  file_buffer->flags = 0;

  return file_buffer;
}

/* Add FILE_BUFFER to our list of already loaded info files. */
static void
remember_info_file (file_buffer)
     FILE_BUFFER *file_buffer;
{
  int i;

  for (i = 0; info_loaded_files && info_loaded_files[i]; i++)
    ;

  add_pointer_to_array (file_buffer, i, info_loaded_files,
                        info_loaded_files_slots, 10, FILE_BUFFER *);
}

/* Forget the contents, tags table, nodes list, and names of FILENAME. */
static void
forget_info_file (filename)
     char *filename;
{
  int i;
  FILE_BUFFER *file_buffer;

  if (!info_loaded_files)
    return;

  for (i = 0; file_buffer = info_loaded_files[i]; i++)
    if (FILENAME_CMP (filename, file_buffer->filename) == 0
        || FILENAME_CMP (filename, file_buffer->fullpath) == 0)
      {
        free (file_buffer->filename);
        free (file_buffer->fullpath);

        if (file_buffer->contents)
          free (file_buffer->contents);
        
        /* free_file_buffer_tags () also kills the subfiles list, since
           the subfiles list is only of use in conjunction with tags. */
        free_file_buffer_tags (file_buffer);

        /* Move rest of list down.  */
        while (info_loaded_files[i + 1])
          {
            info_loaded_files[i] = info_loaded_files[i + 1];
            i++;
          }
        info_loaded_files[i] = 0;

        break;
      }
}

/* Free the tags (if any) associated with FILE_BUFFER. */
static void
free_file_buffer_tags (file_buffer)
     FILE_BUFFER *file_buffer;
{
  int i;

  if (file_buffer->tags)
    {
      TAG *tag;

      for (i = 0; (tag = file_buffer->tags[i]); i++)
        free_info_tag (tag);

      free (file_buffer->tags);
      file_buffer->tags = NULL;
      file_buffer->tags_slots = 0;
    }

  if (file_buffer->subfiles)
    {
      for (i = 0; file_buffer->subfiles[i]; i++)
        free (file_buffer->subfiles[i]);

      free (file_buffer->subfiles);
      file_buffer->subfiles = NULL;
    }
}

/* Free the data associated with TAG, as well as TAG itself. */
static void
free_info_tag (tag)
     TAG *tag;
{
  free (tag->nodename);

  /* We don't free tag->filename, because that filename is part of the
     subfiles list for the containing FILE_BUFFER.  free_info_tags ()
     will free the subfiles when it is appropriate. */

  free (tag);
}

/* Load the contents of FILE_BUFFER->contents.  This function is called
   when a file buffer was loaded, and then in order to conserve memory, the
   file buffer's contents were freed and the pointer was zero'ed.  Note that
   the file was already loaded at least once successfully, so the tags and/or
   nodes members are still correctly filled. */
static void
info_reload_file_buffer_contents (fb)
     FILE_BUFFER *fb;
{
  int is_compressed;

#if defined (HANDLE_MAN_PAGES)
  /* If this is the magic manpage node, don't try to reload, just give up. */
  if (fb->flags & N_IsManPage)
    return;
#endif

  fb->flags &= ~N_IsCompressed;

  /* Let the filesystem do all the work for us. */
  fb->contents =
    filesys_read_info_file (fb->fullpath, &(fb->filesize), &(fb->finfo),
                            &is_compressed);
  if (is_compressed)
    fb->flags |= N_IsCompressed;
}

/* Return the actual starting memory location of NODE, side-effecting
   NODE->contents.  MIN and MAX are bounds for a search if one is necessary.
   Because of the way that tags are implemented, the physical nodestart may
   not actually be where the tag says it is.  If that is the case, but the
   node was found anyway, set N_UpdateTags in NODE->flags.  If the node is
   found, return non-zero.  NODE->contents is returned positioned right after
   the node separator that precedes this node, while the return value is
   position directly on the separator that precedes this node.  If the node
   could not be found, return a NULL pointer. */
static char *
adjust_nodestart (node, min, max)
     NODE *node;
     int min, max;
{
  long position;
  SEARCH_BINDING node_body;

  /* Define the node body. */
  node_body.buffer = node->contents;
  node_body.start = 0;
  node_body.end = max;
  node_body.flags = 0;

  /* Try the optimal case first.  Who knows?  This file may actually be
     formatted (mostly) correctly. */
  if (node_body.buffer[0] != INFO_COOKIE && min > 2)
    node_body.buffer -= 3;

  position = find_node_separator (&node_body);

  /* If we found a node start, then check it out. */
  if (position != -1)
    {
      int sep_len;

      sep_len = skip_node_separator (node->contents);

      /* If we managed to skip a node separator, then check for this node
         being the right one. */
      if (sep_len != 0)
        {
          char *nodedef, *nodestart;
          int offset;

          nodestart = node_body.buffer + position + sep_len;
          nodedef = nodestart;
          offset = string_in_line (INFO_NODE_LABEL, nodedef);

          if (offset != -1)
            {
              nodedef += offset;
              nodedef += skip_whitespace (nodedef);
              offset = skip_node_characters (nodedef, DONT_SKIP_NEWLINES);
              if ((offset == strlen (node->nodename)) &&
                  (strncmp (node->nodename, nodedef, offset) == 0))
                {
                  node->contents = nodestart;
                  return node_body.buffer + position;
                }
            }
        }
    }

  /* Oh well, I guess we have to try to find it in a larger area. */
  node_body.buffer = node->contents - min;
  node_body.start = 0;
  node_body.end = min + max;
  node_body.flags = 0;

  position = find_node_in_binding (node->nodename, &node_body);

  /* If the node couldn't be found, we lose big. */
  if (position == -1)
    return NULL;

  /* Otherwise, the node was found, but the tags table could need updating
     (if we used a tag to get here, that is).  Set the flag in NODE->flags. */
  node->contents = node_body.buffer + position;
  node->contents += skip_node_separator (node->contents);
  if (node->flags & N_HasTagsTable)
    node->flags |= N_UpdateTags;
  return node_body.buffer + position;
}
OpenPOWER on IntegriCloud