contrib/diffutils/src/dir.c

   1 /* Read, sort and compare two directories.  Used for GNU DIFF.
   2
   3    Copyright (C) 1988-1989, 1992-1995, 1998, 2001-2002, 2004, 2006-2007,
   4    2009-2013 Free Software Foundation, Inc.
   5
   6    This file is part of GNU DIFF.
   7
   8    This program is free software: you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation, either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "diff.h"
  22 #include <error.h>
  23 #include <exclude.h>
  24 #include <filenamecat.h>
  25 #include <setjmp.h>
  26 #include <xalloc.h>
  27
  28 /* Read the directory named by DIR and store into DIRDATA a sorted vector
  29    of filenames for its contents.  DIR->desc == -1 means this directory is
  30    known to be nonexistent, so set DIRDATA to an empty vector.
  31    Return -1 (setting errno) if error, 0 otherwise.  */
  32
  33 struct dirdata
  34 {
  35   size_t nnames;        /* Number of names.  */
  36   char const **names;   /* Sorted names of files in dir, followed by 0.  */
  37   char *data;   /* Allocated storage for file names.  */
  38 };
  39
  40 /* Whether file names in directories should be compared with
  41    locale-specific sorting.  */
  42 static bool locale_specific_sorting;
  43
  44 /* Where to go if locale-specific sorting fails.  */
  45 static jmp_buf failed_locale_specific_sorting;
  46
  47 static bool dir_loop (struct comparison const *, int);
  48 static int compare_names_for_qsort (void const *, void const *);
  49
  50
  51 /* Read a directory and get its vector of names.  */
  52
  53 static bool
  54 dir_read (struct file_data const *dir, struct dirdata *dirdata)
  55 {
  56   register struct dirent *next;
  57   register size_t i;
  58
  59   /* Address of block containing the files that are described.  */
  60   char const **names;
  61
  62   /* Number of files in directory.  */
  63   size_t nnames;
  64
  65   /* Allocated and used storage for file name data.  */
  66   char *data;
  67   size_t data_alloc, data_used;
  68
  69   dirdata->names = 0;
  70   dirdata->data = 0;
  71   nnames = 0;
  72   data = 0;
  73
  74   if (dir->desc != -1)
  75     {
  76       /* Open the directory and check for errors.  */
  77       register DIR *reading = opendir (dir->name);
  78       if (!reading)
  79         return false;
  80
  81       /* Initialize the table of filenames.  */
  82
  83       data_alloc = 512;
  84       data_used = 0;
  85       dirdata->data = data = xmalloc (data_alloc);
  86
  87       /* Read the directory entries, and insert the subfiles
  88          into the 'data' table.  */
  89
  90       while ((errno = 0, (next = readdir (reading)) != 0))
  91         {
  92           char *d_name = next->d_name;
  93           size_t d_size = _D_EXACT_NAMLEN (next) + 1;
  94
  95           /* Ignore "." and "..".  */
  96           if (d_name[0] == '.'
  97               && (d_name[1] == 0 || (d_name[1] == '.' && d_name[2] == 0)))
  98             continue;
  99
 100           if (excluded_file_name (excluded, d_name))
 101             continue;
 102
 103           while (data_alloc < data_used + d_size)
 104             {
 105               if (PTRDIFF_MAX / 2 <= data_alloc)
 106                 xalloc_die ();
 107               dirdata->data = data = xrealloc (data, data_alloc *= 2);
 108             }
 109
 110           memcpy (data + data_used, d_name, d_size);
 111           data_used += d_size;
 112           nnames++;
 113         }
 114       if (errno)
 115         {
 116           int e = errno;
 117           closedir (reading);
 118           errno = e;
 119           return false;
 120         }
 121 #if CLOSEDIR_VOID
 122       closedir (reading);
 123 #else
 124       if (closedir (reading) != 0)
 125         return false;
 126 #endif
 127     }
 128
 129   /* Create the 'names' table from the 'data' table.  */
 130   if (PTRDIFF_MAX / sizeof *names - 1 <= nnames)
 131     xalloc_die ();
 132   dirdata->names = names = xmalloc ((nnames + 1) * sizeof *names);
 133   dirdata->nnames = nnames;
 134   for (i = 0;  i < nnames;  i++)
 135     {
 136       names[i] = data;
 137       data += strlen (data) + 1;
 138     }
 139   names[nnames] = 0;
 140   return true;
 141 }
 142
 143 /* Compare file names, returning a value compatible with strcmp.  */
 144
 145 static int
 146 compare_names (char const *name1, char const *name2)
 147 {
 148   if (locale_specific_sorting)
 149     {
 150       int r;
 151       errno = 0;
 152       if (ignore_file_name_case)
 153         r = strcasecoll (name1, name2);
 154       else
 155         r = strcoll (name1, name2);
 156       if (errno)
 157         {
 158           error (0, errno, _("cannot compare file names '%s' and '%s'"),
 159                  name1, name2);
 160           longjmp (failed_locale_specific_sorting, 1);
 161         }
 162       return r;
 163     }
 164
 165   return file_name_cmp (name1, name2);
 166 }
 167
 168 /* Compare names FILE1 and FILE2 when sorting a directory.
 169    Prefer filtered comparison, breaking ties with file_name_cmp.  */
 170
 171 static int
 172 compare_names_for_qsort (void const *file1, void const *file2)
 173 {
 174   char const *const *f1 = file1;
 175   char const *const *f2 = file2;
 176   int diff = compare_names (*f1, *f2);
 177   return diff ? diff : file_name_cmp (*f1, *f2);
 178 }
 179 \f
 180 /* Compare the contents of two directories named in CMP.
 181    This is a top-level routine; it does everything necessary for diff
 182    on two directories.
 183
 184    CMP->file[0].desc == -1 says directory CMP->file[0] doesn't exist,
 185    but pretend it is empty.  Likewise for CMP->file[1].
 186
 187    HANDLE_FILE is a caller-provided subroutine called to handle each file.
 188    It gets three operands: CMP, name of file in dir 0, name of file in dir 1.
 189    These names are relative to the original working directory.
 190
 191    For a file that appears in only one of the dirs, one of the name-args
 192    to HANDLE_FILE is zero.
 193
 194    Returns the maximum of all the values returned by HANDLE_FILE,
 195    or EXIT_TROUBLE if trouble is encountered in opening files.  */
 196
 197 int
 198 diff_dirs (struct comparison const *cmp,
 199            int (*handle_file) (struct comparison const *,
 200                                char const *, char const *))
 201 {
 202   struct dirdata dirdata[2];
 203   int volatile val = EXIT_SUCCESS;
 204   int i;
 205
 206   if ((cmp->file[0].desc == -1 || dir_loop (cmp, 0))
 207       && (cmp->file[1].desc == -1 || dir_loop (cmp, 1)))
 208     {
 209       error (0, 0, _("%s: recursive directory loop"),
 210              cmp->file[cmp->file[0].desc == -1].name);
 211       return EXIT_TROUBLE;
 212     }
 213
 214   /* Get contents of both dirs.  */
 215   for (i = 0; i < 2; i++)
 216     if (! dir_read (&cmp->file[i], &dirdata[i]))
 217       {
 218         perror_with_name (cmp->file[i].name);
 219         val = EXIT_TROUBLE;
 220       }
 221
 222   if (val == EXIT_SUCCESS)
 223     {
 224       char const **volatile names[2];
 225       names[0] = dirdata[0].names;
 226       names[1] = dirdata[1].names;
 227
 228       /* Use locale-specific sorting if possible, else native byte order.  */
 229       locale_specific_sorting = true;
 230       if (setjmp (failed_locale_specific_sorting))
 231         locale_specific_sorting = false;
 232
 233       /* Sort the directories.  */
 234       for (i = 0; i < 2; i++)
 235         qsort (names[i], dirdata[i].nnames, sizeof *dirdata[i].names,
 236                compare_names_for_qsort);
 237
 238       /* If '-S name' was given, and this is the topmost level of comparison,
 239          ignore all file names less than the specified starting name.  */
 240
 241       if (starting_file && ! cmp->parent)
 242         {
 243           while (*names[0] && compare_names (*names[0], starting_file) < 0)
 244             names[0]++;
 245           while (*names[1] && compare_names (*names[1], starting_file) < 0)
 246             names[1]++;
 247         }
 248
 249       /* Loop while files remain in one or both dirs.  */
 250       while (*names[0] || *names[1])
 251         {
 252           /* Compare next name in dir 0 with next name in dir 1.
 253              At the end of a dir,
 254              pretend the "next name" in that dir is very large.  */
 255           int nameorder = (!*names[0] ? 1 : !*names[1] ? -1
 256                            : compare_names (*names[0], *names[1]));
 257
 258           /* Prefer a file_name_cmp match if available.  This algorithm is
 259              O(N**2), where N is the number of names in a directory
 260              that compare_names says are all equal, but in practice N
 261              is so small it's not worth tuning.  */
 262           if (nameorder == 0)
 263             {
 264               int raw_order = file_name_cmp (*names[0], *names[1]);
 265               if (raw_order != 0)
 266                 {
 267                   int greater_side = raw_order < 0;
 268                   int lesser_side = 1 - greater_side;
 269                   char const **lesser = names[lesser_side];
 270                   char const *greater_name = *names[greater_side];
 271                   char const **p;
 272
 273                   for (p = lesser + 1;
 274                        *p && compare_names (*p, greater_name) == 0;
 275                        p++)
 276                     {
 277                       int c = file_name_cmp (*p, greater_name);
 278                       if (0 <= c)
 279                         {
 280                           if (c == 0)
 281                             {
 282                               memmove (lesser + 1, lesser,
 283                                        (char *) p - (char *) lesser);
 284                               *lesser = greater_name;
 285                             }
 286                           break;
 287                         }
 288                     }
 289                 }
 290             }
 291
 292           int v1 = (*handle_file) (cmp,
 293                                    0 < nameorder ? 0 : *names[0]++,
 294                                    nameorder < 0 ? 0 : *names[1]++);
 295           if (val < v1)
 296             val = v1;
 297         }
 298     }
 299
 300   for (i = 0; i < 2; i++)
 301     {
 302       free (dirdata[i].names);
 303       free (dirdata[i].data);
 304     }
 305
 306   return val;
 307 }
 308
 309 /* Return nonzero if CMP is looping recursively in argument I.  */
 310
 311 static bool _GL_ATTRIBUTE_PURE
 312 dir_loop (struct comparison const *cmp, int i)
 313 {
 314   struct comparison const *p = cmp;
 315   while ((p = p->parent))
 316     if (0 < same_file (&p->file[i].stat, &cmp->file[i].stat))
 317       return true;
 318   return false;
 319 }
 320
 321 /* Find a matching filename in a directory.  */
 322
 323 char *
 324 find_dir_file_pathname (char const *dir, char const *file)
 325 {
 326   /* The 'IF_LINT (volatile)' works around what appears to be a bug in
 327      gcc 4.8.0 20120825; see
 328      <http://lists.gnu.org/archive/html/bug-diffutils/2012-08/msg00007.html>.
 329      */
 330   char const * IF_LINT (volatile) match = file;
 331
 332   char *val;
 333   struct dirdata dirdata;
 334   dirdata.names = NULL;
 335   dirdata.data = NULL;
 336
 337   if (ignore_file_name_case)
 338     {
 339       struct file_data filedata;
 340       filedata.name = dir;
 341       filedata.desc = 0;
 342
 343       if (dir_read (&filedata, &dirdata))
 344         {
 345           locale_specific_sorting = true;
 346           if (setjmp (failed_locale_specific_sorting))
 347             match = file; /* longjmp may mess up MATCH.  */
 348           else
 349             {
 350               for (char const **p = dirdata.names; *p; p++)
 351                 if (compare_names (*p, file) == 0)
 352                   {
 353                     if (file_name_cmp (*p, file) == 0)
 354                       {
 355                         match = *p;
 356                         break;
 357                       }
 358                     if (match == file)
 359                       match = *p;
 360                   }
 361             }
 362         }
 363     }
 364
 365   val = file_name_concat (dir, match, NULL);
 366   free (dirdata.names);
 367   free (dirdata.data);
 368   return val;
 369 }