94 lines
2.9 KiB
C
94 lines
2.9 KiB
C
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/* backupfile.c -- make Emacs style backup file names
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Copyright 2017-2020 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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#include <config.h>
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#include "backup-internal.h"
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#include "argmatch.h"
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#include "xalloc.h"
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#include <stdlib.h>
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/* Relative to DIR_FD, return the name of a backup file for the
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existing file FILE, allocated with malloc. Report an error and
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exit if out of memory. Do not call this function if
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backup_type == no_backups. */
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char *
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find_backup_file_name (int dir_fd, char const *file,
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enum backup_type backup_type)
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{
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char *result = backupfile_internal (dir_fd, file, backup_type, false);
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if (!result)
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xalloc_die ();
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return result;
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}
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static char const *const backup_args[] =
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{
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/* In a series of synonyms, present the most meaningful first, so
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that argmatch_valid be more readable. */
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"none", "off",
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"simple", "never",
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"existing", "nil",
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"numbered", "t",
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NULL
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};
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static const enum backup_type backup_types[] =
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{
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no_backups, no_backups,
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simple_backups, simple_backups,
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numbered_existing_backups, numbered_existing_backups,
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numbered_backups, numbered_backups
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};
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/* Ensure that these two vectors have the same number of elements,
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not counting the final NULL in the first one. */
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ARGMATCH_VERIFY (backup_args, backup_types);
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/* Return the type of backup specified by VERSION.
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If VERSION is NULL or the empty string, return numbered_existing_backups.
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If VERSION is invalid or ambiguous, fail with a diagnostic appropriate
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for the specified CONTEXT. Unambiguous abbreviations are accepted. */
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enum backup_type
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get_version (char const *context, char const *version)
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{
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if (version == 0 || *version == 0)
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return numbered_existing_backups;
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else
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return XARGMATCH (context, version, backup_args, backup_types);
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}
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/* Return the type of backup specified by VERSION.
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If VERSION is NULL, use the value of the envvar VERSION_CONTROL.
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If the specified string is invalid or ambiguous, fail with a diagnostic
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appropriate for the specified CONTEXT.
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Unambiguous abbreviations are accepted. */
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enum backup_type
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xget_version (char const *context, char const *version)
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{
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if (version && *version)
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return get_version (context, version);
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else
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return get_version ("$VERSION_CONTROL", getenv ("VERSION_CONTROL"));
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}
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