--- /dev/null
+/* -*- buffer-read-only: t -*- vi: set ro: */
+/* DO NOT EDIT! GENERATED AUTOMATICALLY! */
+/* backupfile.c -- make Emacs style backup file names
+
+ Copyright (C) 1990-2006, 2009-2010 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 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
+ 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, see <http://www.gnu.org/licenses/>. */
+
+/* Written by Paul Eggert and David MacKenzie.
+ Some algorithms adapted from GNU Emacs. */
+
+#include <config.h>
+
+#include "backupfile.h"
+
+#include "argmatch.h"
+#include "dirname.h"
+#include "xalloc.h"
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+#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
+# define REAL_DIR_ENTRY(dp) 1
+#endif
+
+#if ! (HAVE_PATHCONF && defined _PC_NAME_MAX)
+# define pathconf(file, option) (errno = -1)
+#endif
+
+#ifndef _POSIX_NAME_MAX
+# define _POSIX_NAME_MAX 14
+#endif
+#ifndef SIZE_MAX
+# define SIZE_MAX ((size_t) -1)
+#endif
+
+#if defined _XOPEN_NAME_MAX
+# define NAME_MAX_MINIMUM _XOPEN_NAME_MAX
+#else
+# define NAME_MAX_MINIMUM _POSIX_NAME_MAX
+#endif
+
+#ifndef HAVE_DOS_FILE_NAMES
+# define HAVE_DOS_FILE_NAMES 0
+#endif
+#ifndef HAVE_LONG_FILE_NAMES
+# define HAVE_LONG_FILE_NAMES 0
+#endif
+
+/* 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 const *simple_backup_suffix = "~";
+
+
+/* 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. */
+
+static void
+check_extension (char *file, size_t filelen, char e)
+{
+ 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)
+ {
+ /* 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';
+ }
+}
+
+/* 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,
+
+ /* 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;
+ 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 result;
+
+ while ((dp = readdir (dirp)) != NULL)
+ {
+ 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;
+ }
+
+ closedir (dirp);
+ *buffer = buf;
+ return result;
+}
+
+/* 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. */
+
+char *
+find_backup_file_name (char const *file, enum backup_type backup_type)
+{
+ 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);
+
+ 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;
+}
+
+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 const enum backup_type backup_types[] =
+{
+ 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 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)
+{
+ if (version && *version)
+ return get_version (context, version);
+ else
+ return get_version ("$VERSION_CONTROL", getenv ("VERSION_CONTROL"));
+}
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