contrib/diffutils-2.8/src/dir.c

   1 /* Read, sort and compare two directories.  Used for GNU DIFF.
   2
   3    Copyright (C) 1988, 1989, 1992, 1993, 1994, 1995, 1998, 2001, 2002,
   4    2004 Free Software Foundation, Inc.
   5
   6    This file is part of GNU DIFF.
   7
   8    GNU DIFF 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 2, or (at your option)
  11    any later version.
  12
  13    GNU DIFF 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; see the file COPYING.
  20    If not, write to the Free Software Foundation,
  21    59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  22
  23 #include "diff.h"
  24 #include <error.h>
  25 #include <exclude.h>
  26 #include <setjmp.h>
  27 #include <strcase.h>
  28 #include <xalloc.h>
  29
  30 /* Read the directory named by DIR and store into DIRDATA a sorted vector
  31    of filenames for its contents.  DIR->desc == -1 means this directory is
  32    known to be nonexistent, so set DIRDATA to an empty vector.
  33    Return -1 (setting errno) if error, 0 otherwise.  */
  34
  35 struct dirdata
  36 {
  37   size_t nnames;        /* Number of names.  */
  38   char const **names;   /* Sorted names of files in dir, followed by 0.  */
  39   char *data;   /* Allocated storage for file names.  */
  40 };
  41
  42 /* Whether file names in directories should be compared with
  43    locale-specific sorting.  */
  44 static bool locale_specific_sorting;
  45
  46 /* Where to go if locale-specific sorting fails.  */
  47 static jmp_buf failed_locale_specific_sorting;
  48
  49 static bool dir_loop (struct comparison const *, int);
  50 static int compare_names_for_qsort (void const *, void const *);
  51
  52
  53 /* Read a directory and get its vector of names.  */
  54
  55 static bool
  56 dir_read (struct file_data const *dir, struct dirdata *dirdata)
  57 {
  58   register struct dirent *next;
  59   register size_t i;
  60
  61   /* Address of block containing the files that are described.  */
  62   char const **names;
  63
  64   /* Number of files in directory.  */
  65   size_t nnames;
  66
  67   /* Allocated and used storage for file name data.  */
  68   char *data;
  69   size_t data_alloc, data_used;
  70
  71   dirdata->names = 0;
  72   dirdata->data = 0;
  73   nnames = 0;
  74   data = 0;
  75
  76   if (dir->desc != -1)
  77     {
  78       /* Open the directory and check for errors.  */
  79       register DIR *reading = opendir (dir->name);
  80       if (!reading)
  81         return false;
  82
  83       /* Initialize the table of filenames.  */
  84
  85       data_alloc = 512;
  86       data_used = 0;
  87       dirdata->data = data = xmalloc (data_alloc);
  88
  89       /* Read the directory entries, and insert the subfiles
  90          into the `data' table.  */
  91
  92       while ((errno = 0, (next = readdir (reading)) != 0))
  93         {
  94           char *d_name = next->d_name;
  95           size_t d_size = NAMLEN (next) + 1;
  96
  97           /* Ignore "." and "..".  */
  98           if (d_name[0] == '.'
  99               && (d_name[1] == 0 || (d_name[1] == '.' && d_name[2] == 0)))
 100             continue;
 101
 102           if (excluded_filename (excluded, d_name))
 103             continue;
 104
 105           while (data_alloc < data_used + d_size)
 106             {
 107               if (PTRDIFF_MAX / 2 <= data_alloc)
 108                 xalloc_die ();
 109               dirdata->data = data = xrealloc (data, data_alloc *= 2);
 110             }
 111
 112           memcpy (data + data_used, d_name, d_size);
 113           data_used += d_size;
 114           nnames++;
 115         }
 116       if (errno)
 117         {
 118           int e = errno;
 119           closedir (reading);
 120           errno = e;
 121           return false;
 122         }
 123 #if CLOSEDIR_VOID
 124       closedir (reading);
 125 #else
 126       if (closedir (reading) != 0)
 127         return false;
 128 #endif
 129     }
 130
 131   /* Create the `names' table from the `data' table.  */
 132   if (PTRDIFF_MAX / sizeof *names - 1 <= nnames)
 133     xalloc_die ();
 134   dirdata->names = names = xmalloc ((nnames + 1) * sizeof *names);
 135   dirdata->nnames = nnames;
 136   for (i = 0;  i < nnames;  i++)
 137     {
 138       names[i] = data;
 139       data += strlen (data) + 1;
 140     }
 141   names[nnames] = 0;
 142   return true;
 143 }
 144
 145 /* Compare file names, returning a value compatible with strcmp.  */
 146
 147 static int
 148 compare_names (char const *name1, char const *name2)
 149 {
 150   if (locale_specific_sorting)
 151     {
 152       int r;
 153       errno = 0;
 154       if (ignore_file_name_case)
 155         r = strcasecoll (name1, name2);
 156       else
 157         r = strcoll (name1, name2);
 158       if (errno)
 159         {
 160           error (0, errno, _("cannot compare file names `%s' and `%s'"),
 161                  name1, name2);
 162           longjmp (failed_locale_specific_sorting, 1);
 163         }
 164       return r;
 165     }
 166
 167   return (ignore_file_name_case
 168           ? strcasecmp (name1, name2)
 169           : file_name_cmp (name1, name2));
 170 }
 171
 172 /* A wrapper for compare_names suitable as an argument for qsort.  */
 173
 174 static int
 175 compare_names_for_qsort (void const *file1, void const *file2)
 176 {
 177   char const *const *f1 = file1;
 178   char const *const *f2 = file2;
 179   return compare_names (*f1, *f2);
 180 }
 181 \f
 182 /* Compare the contents of two directories named in CMP.
 183    This is a top-level routine; it does everything necessary for diff
 184    on two directories.
 185
 186    CMP->file[0].desc == -1 says directory CMP->file[0] doesn't exist,
 187    but pretend it is empty.  Likewise for CMP->file[1].
 188
 189    HANDLE_FILE is a caller-provided subroutine called to handle each file.
 190    It gets three operands: CMP, name of file in dir 0, name of file in dir 1.
 191    These names are relative to the original working directory.
 192
 193    For a file that appears in only one of the dirs, one of the name-args
 194    to HANDLE_FILE is zero.
 195
 196    Returns the maximum of all the values returned by HANDLE_FILE,
 197    or EXIT_TROUBLE if trouble is encountered in opening files.  */
 198
 199 int
 200 diff_dirs (struct comparison const *cmp,
 201            int (*handle_file) (struct comparison const *,
 202                                char const *, char const *))
 203 {
 204   struct dirdata dirdata[2];
 205   int volatile val = EXIT_SUCCESS;
 206   int i;
 207
 208   if ((cmp->file[0].desc == -1 || dir_loop (cmp, 0))
 209       && (cmp->file[1].desc == -1 || dir_loop (cmp, 1)))
 210     {
 211       error (0, 0, "%s: recursive directory loop",
 212              cmp->file[cmp->file[0].desc == -1].name);
 213       return EXIT_TROUBLE;
 214     }
 215
 216   /* Get contents of both dirs.  */
 217   for (i = 0; i < 2; i++)
 218     if (! dir_read (&cmp->file[i], &dirdata[i]))
 219       {
 220         perror_with_name (cmp->file[i].name);
 221         val = EXIT_TROUBLE;
 222       }
 223
 224   if (val == EXIT_SUCCESS)
 225     {
 226       char const **volatile names[2];
 227       names[0] = dirdata[0].names;
 228       names[1] = dirdata[1].names;
 229
 230       /* Use locale-specific sorting if possible, else native byte order.  */
 231       locale_specific_sorting = true;
 232       if (setjmp (failed_locale_specific_sorting))
 233         locale_specific_sorting = false;
 234
 235       /* Sort the directories.  */
 236       for (i = 0; i < 2; i++)
 237         qsort (names[i], dirdata[i].nnames, sizeof *dirdata[i].names,
 238                compare_names_for_qsort);
 239
 240       /* If `-S name' was given, and this is the topmost level of comparison,
 241          ignore all file names less than the specified starting name.  */
 242
 243       if (starting_file && ! cmp->parent)
 244         {
 245           while (*names[0] && compare_names (*names[0], starting_file) < 0)
 246             names[0]++;
 247           while (*names[1] && compare_names (*names[1], starting_file) < 0)
 248             names[1]++;
 249         }
 250
 251       /* Loop while files remain in one or both dirs.  */
 252       while (*names[0] || *names[1])
 253         {
 254           /* Compare next name in dir 0 with next name in dir 1.
 255              At the end of a dir,
 256              pretend the "next name" in that dir is very large.  */
 257           int nameorder = (!*names[0] ? 1 : !*names[1] ? -1
 258                            : compare_names (*names[0], *names[1]));
 259           int v1 = (*handle_file) (cmp,
 260                                    0 < nameorder ? 0 : *names[0]++,
 261                                    nameorder < 0 ? 0 : *names[1]++);
 262           if (val < v1)
 263             val = v1;
 264         }
 265     }
 266
 267   for (i = 0; i < 2; i++)
 268     {
 269       if (dirdata[i].names)
 270         free (dirdata[i].names);
 271       if (dirdata[i].data)
 272         free (dirdata[i].data);
 273     }
 274
 275   return val;
 276 }
 277
 278 /* Return nonzero if CMP is looping recursively in argument I.  */
 279
 280 static bool
 281 dir_loop (struct comparison const *cmp, int i)
 282 {
 283   struct comparison const *p = cmp;
 284   while ((p = p->parent))
 285     if (0 < same_file (&p->file[i].stat, &cmp->file[i].stat))
 286       return true;
 287   return false;
 288 }