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/* backupfile.c -- make Emacs style backup file names
Copyright 2017-2020 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 <https://www.gnu.org/licenses/>. */
#include <config.h>
#include "backup-internal.h"
#include "argmatch.h"
#include "xalloc.h"
#include <stdlib.h>
/* Relative to DIR_FD, return the name of a backup file for the
existing file FILE, allocated with malloc. Report an error and
exit if out of memory. Do not call this function if
backup_type == no_backups. */
char *
find_backup_file_name (int dir_fd, char const *file,
enum backup_type backup_type)
{
char *result = backupfile_internal (dir_fd, file, backup_type, false);
if (!result)
xalloc_die ();
return result;
}
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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