2 * $OpenBSD: backupfile.c,v 1.19 2006/03/11 19:41:30 otto Exp $
3 * $DragonFly: src/usr.bin/patch/backupfile.c,v 1.5 2008/08/11 00:05:06 joerg Exp $
7 * backupfile.c -- make Emacs style backup file names
9 * Copyright (C) 1990 Free Software Foundation, Inc.
11 * This program is free software; you can redistribute it and/or modify it
12 * without restriction.
14 * This program is distributed in the hope that it will be useful, but WITHOUT
15 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
16 * FITNESS FOR A PARTICULAR PURPOSE.
20 * David MacKenzie <djm@ai.mit.edu>. Some algorithms adapted from GNU Emacs.
31 #include "backupfile.h"
34 #define ISDIGIT(c) (isascii ((unsigned char)c) && isdigit ((unsigned char)c))
36 /* Which type of backup file names are generated. */
37 enum backup_type backup_type = none;
40 * The extension added to file names to produce a simple (as opposed to
41 * numbered) backup file name.
43 const char *simple_backup_suffix = "~";
45 static char *concat(const char *, const char *);
46 static char *make_version_name(const char *, int);
47 static int max_backup_version(const char *, const char *);
48 static int version_number(const char *, const char *, size_t);
49 static int argmatch(const char *, const char **);
50 static void invalid_arg(const char *, const char *, int);
53 * Return the name of the new backup file for file FILE, allocated with
54 * malloc. Return 0 if out of memory. FILE must not end with a '/' unless it
55 * is the root directory. Do not call this function if backup_type == none.
58 find_backup_file_name(const char *file)
60 char *dir, *base_versions, *tmp_file;
63 if (backup_type == simple)
64 return concat(file, simple_backup_suffix);
65 tmp_file = strdup(file);
68 base_versions = concat(basename(tmp_file), ".~");
70 if (base_versions == NULL)
72 tmp_file = strdup(file);
73 if (tmp_file == NULL) {
77 dir = dirname(tmp_file);
83 highest_backup = max_backup_version(base_versions, dir);
86 if (backup_type == numbered_existing && highest_backup == 0)
87 return concat(file, simple_backup_suffix);
88 return make_version_name(file, highest_backup + 1);
92 * Return the number of the highest-numbered backup file for file FILE in
93 * directory DIR. If there are no numbered backups of FILE in DIR, or an
94 * error occurs reading DIR, return 0. FILE should already have ".~" appended
98 max_backup_version(const char *file, const char *dir)
102 int highest_version, this_version;
103 size_t file_name_length;
110 file_name_length = strlen(file);
112 while ((dp = readdir(dirp)) != NULL) {
113 if (dp->d_namlen <= file_name_length)
116 this_version = version_number(file, dp->d_name, file_name_length);
117 if (this_version > highest_version)
118 highest_version = this_version;
121 return highest_version;
125 * Return a string, allocated with malloc, containing "FILE.~VERSION~".
126 * Return 0 if out of memory.
129 make_version_name(const char *file, int version)
133 if (asprintf(&backup_name, "%s.~%d~", file, version) == -1)
139 * If BACKUP is a numbered backup of BASE, return its version number;
140 * otherwise return 0. BASE_LENGTH is the length of BASE. BASE should
141 * already have ".~" appended to it.
144 version_number(const char *base, const char *backup, size_t base_length)
150 if (!strncmp(base, backup, base_length) && ISDIGIT(backup[base_length])) {
151 for (p = &backup[base_length]; ISDIGIT(*p); ++p)
152 version = version * 10 + *p - '0';
153 if (p[0] != '~' || p[1])
160 * Return the newly-allocated concatenation of STR1 and STR2. If out of
164 concat(const char *str1, const char *str2)
168 if (asprintf(&newstr, "%s%s", str1, str2) == -1)
174 * If ARG is an unambiguous match for an element of the null-terminated array
175 * OPTLIST, return the index in OPTLIST of the matched element, else -1 if it
176 * does not match any element or -2 if it is ambiguous (is a prefix of more
180 argmatch(const char *arg, const char **optlist)
182 int i; /* Temporary index in OPTLIST. */
183 size_t arglen; /* Length of ARG. */
184 int matchind = -1; /* Index of first nonexact match. */
185 int ambiguous = 0; /* If nonzero, multiple nonexact match(es). */
187 arglen = strlen(arg);
189 /* Test all elements for either exact match or abbreviated matches. */
190 for (i = 0; optlist[i]; i++) {
191 if (!strncmp(optlist[i], arg, arglen)) {
192 if (strlen(optlist[i]) == arglen)
193 /* Exact match found. */
195 else if (matchind == -1)
196 /* First nonexact match found. */
199 /* Second nonexact match found. */
210 * Error reporting for argmatch. KIND is a description of the type of entity
211 * that was being matched. VALUE is the invalid value that was given. PROBLEM
212 * is the return value from argmatch.
215 invalid_arg(const char *kind, const char *value, int problem)
217 fprintf(stderr, "patch: ");
219 fprintf(stderr, "invalid");
220 else /* Assume -2. */
221 fprintf(stderr, "ambiguous");
222 fprintf(stderr, " %s `%s'\n", kind, value);
225 static const char *backup_args[] = {
226 "never", "simple", "nil", "existing", "t", "numbered", 0
229 static enum backup_type backup_types[] = {
230 simple, simple, numbered_existing,
231 numbered_existing, numbered, numbered
235 * Return the type of backup indicated by VERSION. Unique abbreviations are
239 get_version(const char *version)
243 if (version == NULL || *version == '\0')
244 return numbered_existing;
245 i = argmatch(version, backup_args);
247 return backup_types[i];
248 invalid_arg("version control type", version, i);