summaryrefslogtreecommitdiff
path: root/Build/source/texk/kpathsea/elt-dirs.c
blob: 7d61d850086be490df7768bbfb46e0864425f560 (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
/* elt-dirs.c: Translate a path element to its corresponding director{y,ies}.

   Copyright 1993, 1994, 1995, 1996, 1997, 2008, 2009, 2010, 2011 Karl Berry.
   Copyright 1997, 1998, 1999, 2000, 2005 Olaf Weber.

   This library 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 2.1 of the License, or (at your option) any later version.

   This library 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 library; if not, see <http://www.gnu.org/licenses/>.  */

#include <kpathsea/config.h>

#include <kpathsea/c-pathch.h>
#include <kpathsea/expand.h>
#include <kpathsea/fn.h>
#include <kpathsea/pathsearch.h>
#include <kpathsea/xopendir.h>

/* To avoid giving prototypes for all the routines and then their real
   definitions, we give all the subroutines first.  The entry point is
   the last routine in the file.  */

/* Make a copy of DIR (unless it's null) and save it in L.  Ensure that
   DIR ends with a DIR_SEP for the benefit of later searches.  */

static void
dir_list_add (str_llist_type *l, string dir)
{
  char last_char = dir[strlen (dir) - 1];
  string saved_dir
    = IS_DIR_SEP_CH (last_char) || IS_DEVICE_SEP (last_char)
      ? xstrdup (dir)
      : concat (dir, DIR_SEP_STRING);

  str_llist_add (l, saved_dir);
}


/* If DIR is a directory, add it to the list L.  */

static void
checked_dir_list_add (kpathsea kpse, str_llist_type *l, string dir)
{
    if (kpathsea_dir_p (kpse, dir))
    dir_list_add (l, dir);
}

/* The cache.  Typically, several paths have the same element; for
   example, /usr/local/lib/texmf/fonts//.  We don't want to compute the
   expansion of such a thing more than once.  Even though we also cache
   the dir_links call, that's not enough -- without this path element
   caching as well, the execution time doubles.  */

/* Associate KEY with VALUE.  We implement the cache as a simple linear
   list, since it's unlikely to ever be more than a dozen or so elements
   long.  We don't bother to check here if PATH has already been saved;
   we always add it to our list.  We copy KEY but not VALUE; not sure
   that's right, but it seems to be all that's needed.  */

static void
cache (kpathsea kpse, const_string key,  str_llist_type *value)
{
  kpse->cache_length++;
  XRETALLOC (kpse->the_cache, kpse->cache_length, cache_entry);
  kpse->the_cache[kpse->cache_length - 1].key = xstrdup (key);
  kpse->the_cache[kpse->cache_length - 1].value = value;
}


/* To retrieve, just check the list in order.  */

static str_llist_type *
cached (kpathsea kpse, const_string key)
{
  unsigned p;

  for (p = 0; p < kpse->cache_length; p++)
    {
      if (FILESTRCASEEQ (kpse->the_cache[p].key, key))
        return kpse->the_cache[p].value;
    }

  return NULL;
}

/* Handle the magic path constructs.  */

/* Declare recursively called routine.  */
static void expand_elt (kpathsea, str_llist_type *, string, unsigned);


/* POST is a pointer into the original element (which may no longer be
   ELT) to just after the doubled DIR_SEP, perhaps to the null.  Append
   subdirectories of ELT (up to ELT_LENGTH, which must be a /) to
   STR_LIST_PTR.  */

#ifdef WIN32
/* Shared across recursive calls, it acts like a stack. */
static char dirname[MAX_PATH];
#endif

static void
do_subdir (kpathsea kpse, str_llist_type *str_list_ptr, string elt,
              unsigned elt_length, string post)
{
#ifdef WIN32
  WIN32_FIND_DATA find_file_data;
  HANDLE hnd;
  int proceed;
  int nlinks = 2;
#else
  DIR *dir;
  struct dirent *e;
#endif /* not WIN32 */
  fn_type name;

  /* Some old compilers don't allow aggregate initialization.  */
  name = fn_copy0 (elt, elt_length);

  assert (IS_DIR_SEP_CH (elt[elt_length - 1])
          || IS_DEVICE_SEP (elt[elt_length - 1]));

#if defined (WIN32)
  strcpy(dirname, FN_STRING(name));
  strcat(dirname, "/*.*");         /* "*.*" or "*" -- seems equivalent. */
  hnd = FindFirstFile(dirname, &find_file_data);

  if (hnd == INVALID_HANDLE_VALUE) {
    fn_free(&name);
    return;
  }

  /* Include top level before subdirectories, if nothing to match.  */
  if (*post == 0)
    dir_list_add (str_list_ptr, FN_STRING (name));
  else {
    /* If we do have something to match, see if it exists.  For
       example, POST might be `pk/ljfour', and they might have a
       directory `$TEXMF/fonts/pk/ljfour' that we should find.  */
    fn_str_grow (&name, post);
    expand_elt (kpse, str_list_ptr, FN_STRING (name), elt_length);
    fn_shrink_to (&name, elt_length);
  }
  proceed = 1;
  while (proceed) {
    if (find_file_data.cFileName[0] != '.') {
      int links;

      /* Construct the potential subdirectory name.  */
      fn_str_grow (&name, find_file_data.cFileName);

      /* Maybe we have cached the leafness of this directory.
                 The function will return 0 if unknown,
                 else the actual (Unix-like) value. */
      links = kpathsea_dir_links (kpse, FN_STRING (name), 0);

      if (find_file_data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
        unsigned potential_len = FN_LENGTH (name);
        /* in any case, compute the leafness */
        nlinks++;

        /* It's a directory, so append the separator.  */
        fn_str_grow (&name, DIR_SEP_STRING);
        if (*post != 0) {
          fn_str_grow (&name, post);
          /* Unfortunately we can't check if the new element is
             a leaf directory, because we don't have a directory
             name here, we just have a path spec. This means we
             may descend into a leaf directory cm/pk, if the
             spec is ...fonts//pk//.  */
          expand_elt (kpse, str_list_ptr, FN_STRING (name), potential_len);
          fn_shrink_to (&name, potential_len);
        }
        /* Should we recurse?  To see if the subdirectory is a
           leaf, check if it has two links (one for . and one for
           ..).  This means that symbolic links to directories do
           not affect the leaf-ness.  This is arguably wrong, but
           the only alternative I know of is to stat every entry
           in the directory, and that is unacceptably slow. */

        if (links == 0 || links > 2)
          /* All criteria are met; find subdirectories.  */
        do_subdir (kpse, str_list_ptr, FN_STRING (name),
                     potential_len, post);
        else if (*post == 0)
          /* Nothing to match, no recursive subdirectories to
             look for: we're done with this branch.  Add it.  */
          dir_list_add (str_list_ptr, FN_STRING (name));
      }
      fn_shrink_to (&name, elt_length);
    }
    proceed = FindNextFile (hnd, &find_file_data);
  }
  /* Update the leafness of name. */
  kpathsea_dir_links(kpse, FN_STRING(name), nlinks);
  fn_free (&name);
  FindClose(hnd);

#else /* not WIN32 */

  /* If we can't open it, quit.  */
  dir = opendir (FN_STRING (name));
  if (dir == NULL)
    {
      fn_free (&name);
      return;
    }

  /* Include top level before subdirectories, if nothing to match.  */
  if (*post == 0)
    dir_list_add (str_list_ptr, FN_STRING (name));
  else
    { /* If we do have something to match, see if it exists.  For
         example, POST might be `pk/ljfour', and they might have a
         directory `$TEXMF/fonts/pk/ljfour' that we should find.  */
      fn_str_grow (&name, post);
      expand_elt (kpse, str_list_ptr, FN_STRING (name), elt_length);
      fn_shrink_to (&name, elt_length);
    }

  while ((e = readdir (dir)) != NULL)
    { /* If it begins with a `.', never mind.  (This allows ``hidden''
         directories that the algorithm won't find.)  */
      if (e->d_name[0] != '.')
        {
          int links;

          /* Construct the potential subdirectory name.  */
          fn_str_grow (&name, e->d_name);

          /* If we can't stat it, or if it isn't a directory, continue.  */
          links = kpathsea_dir_links (kpse, FN_STRING (name), 0);

          if (links >= 0)
            {
              unsigned potential_len = FN_LENGTH (name);

              /* It's a directory, so append the separator.  */
              fn_str_grow (&name, DIR_SEP_STRING);

              if (*post != 0)
                {
                  fn_str_grow (&name, post);
                  /* Unfortunately we can't check if the new element is
                     a leaf directory, because we don't have a directory
                     name here, we just have a path spec. This means we
                     may descend into a leaf directory cm/pk, if the
                     spec is ...fonts//pk//.  */
                  expand_elt (kpse, str_list_ptr, FN_STRING (name),
                              potential_len);
                  fn_shrink_to (&name, potential_len);
                }

              /* Should we recurse?  To see if the subdirectory is a
                 leaf, check if it has two links (one for . and one for
                 ..).  This means that symbolic links to directories do
                 not affect the leaf-ness.  This is arguably wrong, but
                 the only alternative I know of is to stat every entry
                 in the directory, and that is unacceptably slow.

                 The #ifdef here makes all this configurable at
                 compile-time, so that if we're using VMS directories or
                 some such, we can still find subdirectories, even if it
                 is much slower.  */
#ifdef ST_NLINK_TRICK
              /* With SAS/C++ 6.55 on the Amiga, stat sets the st_nlink
                 field to -1 for a file, or to 1 for a directory.
                 Cygwin 1.7 also leaves st_nlink as 1:
                 http://cygwin.com/ml/cygwin-developers/2008-04/msg00110.html
                 */
              if (links != 2)
#endif /* ST_NLINK_TRICK */
                /* All criteria are met; find subdirectories.  */
                  do_subdir (kpse, str_list_ptr, FN_STRING (name),
                           potential_len, post);
#ifdef ST_NLINK_TRICK
              else if (*post == 0)
                /* Nothing to match, no recursive subdirectories to
                   look for: we're done with this branch.  Add it.  */
                dir_list_add (str_list_ptr, FN_STRING (name));
#endif
            }

          /* Remove the directory entry we just checked from `name'.  */
          fn_shrink_to (&name, elt_length);
        }
    }

  fn_free (&name);
  xclosedir (dir);
#endif /* not WIN32 */
}


/* Assume ELT is non-empty and non-NULL.  Return list of corresponding
   directories (with no terminating NULL entry) in STR_LIST_PTR.  Start
   looking for magic constructs at START.  */

static void
expand_elt (kpathsea kpse, str_llist_type * str_list_ptr, string elt,
               unsigned start)
{
  string dir = elt + start, post;

  while (*dir != 0)
    {
      if (IS_DIR_SEP_CH (*dir))
        {
          /* If two or more consecutive /'s, find subdirectories.  */
          if (IS_DIR_SEP_CH (dir[1]))
            {
              for (post = dir + 1; IS_DIR_SEP_CH (*post); post++) ;
            do_subdir (kpse, str_list_ptr, elt, dir - elt + 1, post);
              return;
            }

          /* No special stuff at this slash.  Keep going.  */
        }

      dir++;
    }

  /* When we reach the end of ELT, it will be a normal filename.  */
  checked_dir_list_add (kpse, str_list_ptr, elt);
}

/*  On win32 we slashify ELT, i.e., change '\\' to '/', and then can use
   IS_DIR_SEP_CH instead of IS_DIR_SEP and need not test for the presence
   of 2-Byte Kanji (CP 932, SJIS) codes.  */

/* The first bits of a path element can be problematic because they
   look like a request to expand a whole disk, rather than a subtree.
   - It can contain a drive specification.
   - It can be a UNC path (w32, but they are part of the single
     Unix specification as well).
   The argument is a string as the function can diddle into the argument
   to canonicalize it, which tends to matter on windows platforms.
   - Always lower-case drive letters a-z, even those filesystem that
     preserve case in filenames do not care about the case of the drive
     letters.
   - Remove unneeded double slashes. The problem is Windows does not
     handle well filenames like c://dir/foo. So canonicalize the names.
     The resulting name will always be shorter than the one passed, so no
     problem.
   - Remove multiple leading slashes to prevent expanding from the root
     of a UNIX filesystem tree.  */

unsigned
kpathsea_normalize_path (kpathsea kpse, string elt)
{
  unsigned ret;
  unsigned i;

#if defined(WIN32)
  for (i = 0; elt[i]; i++) {
    if (elt[i] == '\\')
      elt[i] = '/';
    else if (IS_KANJI(elt + i))
      i++;
  }
#endif

  if (NAME_BEGINS_WITH_DEVICE(elt)) {
    if (*elt >= 'A' && *elt <= 'Z')
      *elt += 'a' - 'A';
    ret = 2;

  } else if (IS_UNC_NAME(elt)) {
    for (ret = 2; elt[ret] && !IS_DIR_SEP_CH(elt[ret]); ret++)
      ;

  } else
    ret = 0;

  for (i = ret; IS_DIR_SEP_CH(elt[i]); ++i)
    ;
  if (i > ret + 1) {
#ifdef KPSE_DEBUG
  if (KPATHSEA_DEBUG_P (KPSE_DEBUG_STAT))
    DEBUGF2 ("kpse_normalize_path (%s) => %u\n", elt, ret);
#endif /* KPSE_DEBUG */

    memmove (elt + ret + 1, elt + i, strlen (elt + i) + 1);
  }

  return ret;
}

/* Here is the entry point.  Returns directory list for ELT.  */

str_llist_type *
kpathsea_element_dirs (kpathsea kpse, string elt)
{
  str_llist_type *ret;
  unsigned i;

  /* If given nothing, return nothing.  */
  if (!elt || !*elt)
    return NULL;

  /* Normalize ELT before looking for a cached value.  */
  i = kpathsea_normalize_path (kpse, elt);

  /* If we've already cached the answer for ELT, return it.  */
  ret = cached (kpse, elt);
  if (ret)
    return ret;

  /* We're going to have a real directory list to return.  */
  ret = XTALLOC1 (str_llist_type);
  *ret = NULL;

  /* We handle the hard case in a subroutine.  */
  expand_elt (kpse, ret, elt, i);

  /* Remember the directory list we just found, in case future calls are
     made with the same ELT.  */
  cache (kpse, elt, ret);

#ifdef KPSE_DEBUG
  if (KPATHSEA_DEBUG_P (KPSE_DEBUG_EXPAND))
    {
      DEBUGF1 ("path element %s =>", elt);
      if (ret)
        {
          str_llist_elt_type *e;
          for (e = *ret; e; e = STR_LLIST_NEXT (*e))
            fprintf (stderr, " %s", STR_LLIST (*e));
        }
      putc ('\n', stderr);
      fflush (stderr);
    }
#endif /* KPSE_DEBUG */

  return ret;
}

#ifdef TEST

void
print_element_dirs (const_string elt)
{
  str_llist_type *dirs;

  printf ("Directories of %s:\t", elt ? elt : "(nil)");
  fflush (stdout);

  dirs = kpathsea_element_dirs (kpse_def, elt);

  if (!dirs)
    printf ("(nil)");
  else
    {
      str_llist_elt_type *dir;
      for (dir = *dirs; dir; dir = STR_LLIST_NEXT (*dir))
        {
          string d = STR_LLIST (*dir);
          printf ("%s ", *d ? d : "`'");
        }
    }

  putchar ('\n');
}

int
main ()
{
  /* DEBUG_SET (DEBUG_STAT); */
  /* All lists end with NULL.  */
  print_element_dirs (NULL);    /* */
  print_element_dirs ("");      /* ./ */
  print_element_dirs ("/k");    /* */
  print_element_dirs (".//");   /* ./ ./archive/ */
  print_element_dirs (".//archive");    /* ./ ./archive/ */
#ifdef AMIGA
  print_element_dirs ("TeXMF:AmiWeb2c/texmf/fonts//"); /* lots */
  print_element_dirs ("TeXMF:AmiWeb2c/share/texmf/fonts//bakoma"); /*just one*/
  print_element_dirs ("TeXMF:AmiWeb2c/texmf/fonts//"); /* lots again [cache] */
  print_element_dirs ("TeXMF:");        /* TeXMF: */
  print_element_dirs ("TeXMF:/");       /* TeXMF: and all subdirs */
#else /* not AMIGA */
  print_element_dirs ("/tmp/fonts//");  /* no need to stat anything */
  print_element_dirs ("/usr/local/lib/tex/fonts//");      /* lots */
  print_element_dirs ("/usr/local/lib/tex/fonts//times"); /* just one */
  print_element_dirs ("/usr/local/lib/tex/fonts//"); /* lots again [cache] */
  print_element_dirs ("~karl");         /* tilde expansion */
  print_element_dirs ("$karl");         /* variable expansion */
  print_element_dirs ("~${LOGNAME}");   /* both */
#endif /* not AMIGA */
  return 0;
}

#endif /* TEST */


/*
Local variables:
standalone-compile-command: "gcc -g -I. -I.. -DTEST elt-dirs.c kpathsea.a"
End:
*/