X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fbackupfile.c;h=2ad030f8dc5a9d2abed1ddd93dba56fa0732ac5f;hb=1276a2c5f24c0c932426aca9c899fa524d2443f2;hp=ddf3fa7894643362b3c0b8ac3d8e2d6cb0baf4f7;hpb=92a0e357d2915935df140c766bf98db53a53a455;p=gnulib.git

diff --git a/lib/backupfile.c b/lib/backupfile.c
index ddf3fa789..2ad030f8d 100644
--- a/lib/backupfile.c
+++ b/lib/backupfile.c
@@ -1,10 +1,11 @@
 /* backupfile.c -- make Emacs style backup file names
-   Copyright (C) 1990 Free Software Foundation, Inc.
 
-   This program is free software; you can redistribute it and/or modify
+   Copyright (C) 1990-2006, 2009-2014 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.
+   the Free Software Foundation; either version 3 of the License, 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
@@ -12,227 +13,343 @@
    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., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
-/* David MacKenzie <djm@gnu.ai.mit.edu>.
-   Some algorithms adapted from GNU Emacs. */
+/* Written by Paul Eggert and David MacKenzie.
+   Some algorithms adapted from GNU Emacs.  */
 
-#ifdef HAVE_CONFIG_H
-#if defined (CONFIG_BROKETS)
-/* We use <config.h> instead of "config.h" so that a compilation
-   using -I. -I will use ./config.h rather than /config.h
-   (which it would do because it found this file in ).  */
 #include <config.h>
-#else
-#include "config.h"
-#endif
-#endif
 
-#include <stdio.h>
-#include <ctype.h>
-#include <sys/types.h>
 #include "backupfile.h"
-#if defined(STDC_HEADERS) || defined(HAVE_STRING_H)
+
+#include "argmatch.h"
+#include "dirname.h"
+#include "xalloc.h"
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdlib.h>
 #include <string.h>
-#ifndef index
-#define index strchr
-#endif
-#ifndef rindex
-#define rindex strrchr
+
+#include <limits.h>
+
+#include <unistd.h>
+
+#include "dirent--.h"
+#ifndef _D_EXACT_NAMLEN
+# define _D_EXACT_NAMLEN(dp) strlen ((dp)->d_name)
 #endif
+#if D_INO_IN_DIRENT
+# define REAL_DIR_ENTRY(dp) ((dp)->d_ino != 0)
 #else
-#include <strings.h>
+# define REAL_DIR_ENTRY(dp) 1
 #endif
 
-#if defined(DIRENT) || defined(_POSIX_VERSION)
-#include <dirent.h>
-#define NLENGTH(direct) (strlen((direct)->d_name))
-#else /* not (DIRENT or _POSIX_VERSION) */
-#define dirent direct
-#define NLENGTH(direct) ((direct)->d_namlen)
-#ifdef SYSNDIR
-#include <sys/ndir.h>
-#endif /* SYSNDIR */
-#ifdef SYSDIR
-#include <sys/dir.h>
-#endif /* SYSDIR */
-#ifdef NDIR
-#include <ndir.h>
-#endif /* NDIR */
-#endif /* DIRENT or _POSIX_VERSION */
-
-#ifdef VOID_CLOSEDIR
-/* Fake a return value. */
-#define CLOSEDIR(d) (closedir (d), 0)
-#else
-#define CLOSEDIR(d) closedir (d)
+#if ! (HAVE_PATHCONF && defined _PC_NAME_MAX)
+# define pathconf(file, option) (errno = -1)
 #endif
 
-#ifdef STDC_HEADERS
-#include <stdlib.h>
-#else
-char *malloc ();
+#ifndef _POSIX_NAME_MAX
+# define _POSIX_NAME_MAX 14
 #endif
-
-#if !defined (isascii) || defined (STDC_HEADERS)
-#undef isascii
-#define isascii(c) 1
+#ifndef SIZE_MAX
+# define SIZE_MAX ((size_t) -1)
 #endif
 
-#define ISDIGIT(c) (isascii ((unsigned char ) c) \
-		    && isdigit ((unsigned char) (c)))
-
-#if defined (HAVE_UNISTD_H)
-#include <unistd.h>
+#if defined _XOPEN_NAME_MAX
+# define NAME_MAX_MINIMUM _XOPEN_NAME_MAX
+#else
+# define NAME_MAX_MINIMUM _POSIX_NAME_MAX
 #endif
 
-#if defined (_POSIX_VERSION)
-/* POSIX does not require that the d_ino field be present, and some
-   systems do not provide it. */
-#define REAL_DIR_ENTRY(dp) 1
-#else
-#define REAL_DIR_ENTRY(dp) ((dp)->d_ino != 0)
+#ifndef HAVE_DOS_FILE_NAMES
+# define HAVE_DOS_FILE_NAMES 0
+#endif
+#ifndef HAVE_LONG_FILE_NAMES
+# define HAVE_LONG_FILE_NAMES 0
 #endif
 
-/* Which type of backup file names are generated. */
-enum backup_type backup_type = none;
+/* ISDIGIT differs from isdigit, as follows:
+   - Its arg may be any int or unsigned int; it need not be an unsigned char
+     or EOF.
+   - It's typically faster.
+   POSIX says that only '0' through '9' are digits.  Prefer ISDIGIT to
+   ISDIGIT unless it's important to use the locale's definition
+   of "digit" even when the host does not conform to POSIX.  */
+#define ISDIGIT(c) ((unsigned int) (c) - '0' <= 9)
 
 /* The extension added to file names to produce a simple (as opposed
    to numbered) backup file name. */
-char *simple_backup_suffix = "~";
+char const *simple_backup_suffix = "~";
 
-char *basename ();
-char *dirname ();
-static char *concat ();
-char *find_backup_file_name ();
-static char *make_version_name ();
-static int max_backup_version ();
-static int version_number ();
 
-/* Return the name of the new backup file for file FILE,
-   allocated with malloc.  Return 0 if out of memory.
-   FILE must not end with a '/' unless it is the root directory.
-   Do not call this function if backup_type == none. */
+/* If FILE (which was of length FILELEN before an extension was
+   appended to it) is too long, replace the extension with the single
+   char E.  If the result is still too long, remove the char just
+   before E.  */
 
-char *
-find_backup_file_name (file)
-     char *file;
+static void
+check_extension (char *file, size_t filelen, char e)
 {
-  char *dir;
-  char *base_versions;
-  int highest_backup;
-
-  if (backup_type == simple)
-    return concat (file, simple_backup_suffix);
-  base_versions = concat (basename (file), ".~");
-  if (base_versions == 0)
-    return 0;
-  dir = dirname (file);
-  if (dir == 0)
+  char *base = last_component (file);
+  size_t baselen = base_len (base);
+  size_t baselen_max = HAVE_LONG_FILE_NAMES ? 255 : NAME_MAX_MINIMUM;
+
+  if (HAVE_DOS_FILE_NAMES || NAME_MAX_MINIMUM < baselen)
     {
-      free (base_versions);
-      return 0;
+      /* The new base name is long enough to require a pathconf check.  */
+      long name_max;
+
+      /* Temporarily modify the buffer into its parent directory name,
+         invoke pathconf on the directory, and then restore the buffer.  */
+      char tmp[sizeof "."];
+      memcpy (tmp, base, sizeof ".");
+      strcpy (base, ".");
+      errno = 0;
+      name_max = pathconf (file, _PC_NAME_MAX);
+      if (0 <= name_max || errno == 0)
+        {
+          long size = baselen_max = name_max;
+          if (name_max != size)
+            baselen_max = SIZE_MAX;
+        }
+      memcpy (base, tmp, sizeof ".");
+    }
+
+  if (HAVE_DOS_FILE_NAMES && baselen_max <= 12)
+    {
+      /* Live within DOS's 8.3 limit.  */
+      char *dot = strchr (base, '.');
+      if (!dot)
+        baselen_max = 8;
+      else
+        {
+          char const *second_dot = strchr (dot + 1, '.');
+          baselen_max = (second_dot
+                         ? second_dot - base
+                         : dot + 1 - base + 3);
+        }
+    }
+
+  if (baselen_max < baselen)
+    {
+      baselen = file + filelen - base;
+      if (baselen_max <= baselen)
+        baselen = baselen_max - 1;
+      base[baselen] = e;
+      base[baselen + 1] = '\0';
     }
-  highest_backup = max_backup_version (base_versions, dir);
-  free (base_versions);
-  free (dir);
-  if (backup_type == numbered_existing && highest_backup == 0)
-    return concat (file, simple_backup_suffix);
-  return make_version_name (file, highest_backup + 1);
 }
 
-/* Return the number of the highest-numbered backup file for file
-   FILE in directory DIR.  If there are no numbered backups
-   of FILE in DIR, or an error occurs reading DIR, return 0.
-   FILE should already have ".~" appended to it. */
+/* Returned values for NUMBERED_BACKUP.  */
+
+enum numbered_backup_result
+  {
+    /* The new backup name is the same length as an existing backup
+       name, so it's valid for that directory.  */
+    BACKUP_IS_SAME_LENGTH,
 
-static int
-max_backup_version (file, dir)
-     char *file, *dir;
+    /* Some backup names already exist, but the returned name is longer
+       than any of them, and its length should be checked.  */
+    BACKUP_IS_LONGER,
+
+    /* There are no existing backup names.  The new name's length
+       should be checked.  */
+    BACKUP_IS_NEW
+  };
+
+/* *BUFFER contains a file name.  Store into *BUFFER the next backup
+   name for the named file, with a version number greater than all the
+   existing numbered backups.  Reallocate *BUFFER as necessary; its
+   initial allocated size is BUFFER_SIZE, which must be at least 4
+   bytes longer than the file name to make room for the initially
+   appended ".~1".  FILELEN is the length of the original file name.
+   The returned value indicates what kind of backup was found.  If an
+   I/O or other read error occurs, use the highest backup number that
+   was found.  */
+
+static enum numbered_backup_result
+numbered_backup (char **buffer, size_t buffer_size, size_t filelen)
 {
+  enum numbered_backup_result result = BACKUP_IS_NEW;
   DIR *dirp;
   struct dirent *dp;
-  int highest_version;
-  int this_version;
-  int file_name_length;
-  
-  dirp = opendir (dir);
+  char *buf = *buffer;
+  size_t versionlenmax = 1;
+  char *base = last_component (buf);
+  size_t base_offset = base - buf;
+  size_t baselen = base_len (base);
+
+  /* Temporarily modify the buffer into its parent directory name,
+     open the directory, and then restore the buffer.  */
+  char tmp[sizeof "."];
+  memcpy (tmp, base, sizeof ".");
+  strcpy (base, ".");
+  dirp = opendir (buf);
+  memcpy (base, tmp, sizeof ".");
+  strcpy (base + baselen, ".~1~");
+
   if (!dirp)
-    return 0;
-  
-  highest_version = 0;
-  file_name_length = strlen (file);
+    return result;
 
-  while ((dp = readdir (dirp)) != 0)
+  while ((dp = readdir (dirp)) != NULL)
     {
-      if (!REAL_DIR_ENTRY (dp) || NLENGTH (dp) <= file_name_length)
-	continue;
-      
-      this_version = version_number (file, dp->d_name, file_name_length);
-      if (this_version > highest_version)
-	highest_version = this_version;
+      char const *p;
+      char *q;
+      bool all_9s;
+      size_t versionlen;
+      size_t new_buflen;
+
+      if (! REAL_DIR_ENTRY (dp) || _D_EXACT_NAMLEN (dp) < baselen + 4)
+        continue;
+
+      if (memcmp (buf + base_offset, dp->d_name, baselen + 2) != 0)
+        continue;
+
+      p = dp->d_name + baselen + 2;
+
+      /* Check whether this file has a version number and if so,
+         whether it is larger.  Use string operations rather than
+         integer arithmetic, to avoid problems with integer overflow.  */
+
+      if (! ('1' <= *p && *p <= '9'))
+        continue;
+      all_9s = (*p == '9');
+      for (versionlen = 1; ISDIGIT (p[versionlen]); versionlen++)
+        all_9s &= (p[versionlen] == '9');
+
+      if (! (p[versionlen] == '~' && !p[versionlen + 1]
+             && (versionlenmax < versionlen
+                 || (versionlenmax == versionlen
+                     && memcmp (buf + filelen + 2, p, versionlen) <= 0))))
+        continue;
+
+      /* This directory has the largest version number seen so far.
+         Append this highest numbered extension to the file name,
+         prepending '0' to the number if it is all 9s.  */
+
+      versionlenmax = all_9s + versionlen;
+      result = (all_9s ? BACKUP_IS_LONGER : BACKUP_IS_SAME_LENGTH);
+      new_buflen = filelen + 2 + versionlenmax + 1;
+      if (buffer_size <= new_buflen)
+        {
+          buf = xnrealloc (buf, 2, new_buflen);
+          buffer_size = new_buflen * 2;
+        }
+      q = buf + filelen;
+      *q++ = '.';
+      *q++ = '~';
+      *q = '0';
+      q += all_9s;
+      memcpy (q, p, versionlen + 2);
+
+      /* Add 1 to the version number.  */
+
+      q += versionlen;
+      while (*--q == '9')
+        *q = '0';
+      ++*q;
     }
-  if (CLOSEDIR (dirp))
-    return 0;
-  return highest_version;
+
+  closedir (dirp);
+  *buffer = buf;
+  return result;
 }
 
-/* Return a string, allocated with malloc, containing
-   "FILE.~VERSION~".  Return 0 if out of memory. */
+/* Return the name of the new backup file for the existing file FILE,
+   allocated with malloc.  Report an error and fail if out of memory.
+   Do not call this function if backup_type == no_backups.  */
 
-static char *
-make_version_name (file, version)
-     char *file;
-     int version;
+char *
+find_backup_file_name (char const *file, enum backup_type backup_type)
 {
-  char *backup_name;
+  size_t filelen = strlen (file);
+  char *s;
+  size_t ssize;
+  bool simple = true;
+
+  /* Allow room for simple or ".~N~" backups.  The guess must be at
+     least sizeof ".~1~", but otherwise will be adjusted as needed.  */
+  size_t simple_backup_suffix_size = strlen (simple_backup_suffix) + 1;
+  size_t backup_suffix_size_guess = simple_backup_suffix_size;
+  enum { GUESS = sizeof ".~12345~" };
+  if (backup_suffix_size_guess < GUESS)
+    backup_suffix_size_guess = GUESS;
+
+  ssize = filelen + backup_suffix_size_guess + 1;
+  s = xmalloc (ssize);
+  memcpy (s, file, filelen + 1);
 
-  backup_name = malloc (strlen (file) + 16);
-  if (backup_name == 0)
-    return 0;
-  sprintf (backup_name, "%s.~%d~", file, version);
-  return backup_name;
+  if (backup_type != simple_backups)
+    switch (numbered_backup (&s, ssize, filelen))
+      {
+      case BACKUP_IS_SAME_LENGTH:
+        return s;
+
+      case BACKUP_IS_LONGER:
+        simple = false;
+        break;
+
+      case BACKUP_IS_NEW:
+        simple = (backup_type == numbered_existing_backups);
+        break;
+      }
+
+  if (simple)
+    memcpy (s + filelen, simple_backup_suffix, simple_backup_suffix_size);
+  check_extension (s, filelen, '~');
+  return s;
 }
 
-/* If BACKUP is a numbered backup of BASE, return its version number;
-   otherwise return 0.  BASE_LENGTH is the length of BASE.
-   BASE should already have ".~" appended to it. */
+static char const * const backup_args[] =
+{
+  /* In a series of synonyms, present the most meaningful first, so
+     that argmatch_valid be more readable. */
+  "none", "off",
+  "simple", "never",
+  "existing", "nil",
+  "numbered", "t",
+  NULL
+};
 
-static int
-version_number (base, backup, base_length)
-     char *base;
-     char *backup;
-     int base_length;
+static const enum backup_type backup_types[] =
 {
-  int version;
-  char *p;
-  
-  version = 0;
-  if (!strncmp (base, backup, base_length) && ISDIGIT (backup[base_length]))
-    {
-      for (p = &backup[base_length]; ISDIGIT (*p); ++p)
-	version = version * 10 + *p - '0';
-      if (p[0] != '~' || p[1])
-	version = 0;
-    }
-  return version;
+  no_backups, no_backups,
+  simple_backups, simple_backups,
+  numbered_existing_backups, numbered_existing_backups,
+  numbered_backups, numbered_backups
+};
+
+/* Ensure that these two vectors have the same number of elements,
+   not counting the final NULL in the first one.  */
+ARGMATCH_VERIFY (backup_args, backup_types);
+
+/* Return the type of backup specified by VERSION.
+   If VERSION is NULL or the empty string, return numbered_existing_backups.
+   If VERSION is invalid or ambiguous, fail with a diagnostic appropriate
+   for the specified CONTEXT.  Unambiguous abbreviations are accepted.  */
+
+enum backup_type
+get_version (char const *context, char const *version)
+{
+  if (version == 0 || *version == 0)
+    return numbered_existing_backups;
+  else
+    return XARGMATCH (context, version, backup_args, backup_types);
 }
 
-/* Return the newly-allocated concatenation of STR1 and STR2.
-   If out of memory, return 0. */
 
-static char *
-concat (str1, str2)
-     char *str1, *str2;
+/* Return the type of backup specified by VERSION.
+   If VERSION is NULL, use the value of the envvar VERSION_CONTROL.
+   If the specified string is invalid or ambiguous, fail with a diagnostic
+   appropriate for the specified CONTEXT.
+   Unambiguous abbreviations are accepted.  */
+
+enum backup_type
+xget_version (char const *context, char const *version)
 {
-  char *newstr;
-  int str1_length = strlen (str1);
-
-  newstr = malloc (str1_length + strlen (str2) + 1);
-  if (newstr == 0)
-    return 0;
-  strcpy (newstr, str1);
-  strcpy (newstr + str1_length, str2);
-  return newstr;
+  if (version && *version)
+    return get_version (context, version);
+  else
+    return get_version ("$VERSION_CONTROL", getenv ("VERSION_CONTROL"));
 }