2 * $OpenBSD: backupfile.c,v 1.18 2004/08/05 21:47:24 deraadt Exp $
3 * $DragonFly: src/usr.bin/patch/backupfile.c,v 1.2 2004/09/28 19:09:50 joerg Exp $
7 * backupfile.c -- make Emacs style backup file names Copyright (C) 1990 Free
8 * Software Foundation, Inc.
10 * This program is free software; you can redistribute it and/or modify it
11 * without restriction.
13 * This program is distributed in the hope that it will be useful, but WITHOUT
14 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 * FITNESS FOR A PARTICULAR PURPOSE.
19 * David MacKenzie <djm@ai.mit.edu>. Some algorithms adapted from GNU Emacs.
30 #include "backupfile.h"
33 #define ISDIGIT(c) (isascii (c) && isdigit (c))
35 /* Which type of backup file names are generated. */
36 enum backup_type backup_type = none;
39 * The extension added to file names to produce a simple (as opposed to
40 * numbered) backup file name.
42 const char *simple_backup_suffix = "~";
44 static char *concat(const char *, const char *);
45 static char *make_version_name(const char *, int);
46 static int max_backup_version(const char *, const char *);
47 static int version_number(const char *, const char *, int);
48 static int argmatch(const char *, const char **);
49 static void invalid_arg(const char *, const char *, int);
52 * Return the name of the new backup file for file FILE, allocated with
53 * malloc. Return 0 if out of memory. FILE must not end with a '/' unless it
54 * is the root directory. Do not call this function if backup_type == none.
57 find_backup_file_name(const char *file)
59 char *dir, *base_versions;
62 if (backup_type == simple)
63 return concat(file, simple_backup_suffix);
64 base_versions = concat(basename(file), ".~");
65 if (base_versions == NULL)
72 highest_backup = max_backup_version(base_versions, dir);
74 if (backup_type == numbered_existing && highest_backup == 0)
75 return concat(file, simple_backup_suffix);
76 return make_version_name(file, highest_backup + 1);
80 * Return the number of the highest-numbered backup file for file FILE in
81 * directory DIR. If there are no numbered backups of FILE in DIR, or an
82 * error occurs reading DIR, return 0. FILE should already have ".~" appended
86 max_backup_version(const char *file, const char *dir)
90 int highest_version, this_version, file_name_length;
97 file_name_length = strlen(file);
99 while ((dp = readdir(dirp)) != NULL) {
100 if (dp->d_namlen <= file_name_length)
103 this_version = version_number(file, dp->d_name, file_name_length);
104 if (this_version > highest_version)
105 highest_version = this_version;
108 return highest_version;
112 * Return a string, allocated with malloc, containing "FILE.~VERSION~".
113 * Return 0 if out of memory.
116 make_version_name(const char *file, int version)
120 if (asprintf(&backup_name, "%s.~%d~", file, version) == -1)
126 * If BACKUP is a numbered backup of BASE, return its version number;
127 * otherwise return 0. BASE_LENGTH is the length of BASE. BASE should
128 * already have ".~" appended to it.
131 version_number(const char *base, const char *backup, int base_length)
137 if (!strncmp(base, backup, base_length) && ISDIGIT(backup[base_length])) {
138 for (p = &backup[base_length]; ISDIGIT(*p); ++p)
139 version = version * 10 + *p - '0';
140 if (p[0] != '~' || p[1])
147 * Return the newly-allocated concatenation of STR1 and STR2. If out of
151 concat(const char *str1, const char *str2)
155 if (asprintf(&newstr, "%s%s", str1, str2) == -1)
161 * If ARG is an unambiguous match for an element of the null-terminated array
162 * OPTLIST, return the index in OPTLIST of the matched element, else -1 if it
163 * does not match any element or -2 if it is ambiguous (is a prefix of more
167 argmatch(const char *arg, const char **optlist)
169 int i; /* Temporary index in OPTLIST. */
170 size_t arglen; /* Length of ARG. */
171 int matchind = -1; /* Index of first nonexact match. */
172 int ambiguous = 0; /* If nonzero, multiple nonexact match(es). */
174 arglen = strlen(arg);
176 /* Test all elements for either exact match or abbreviated matches. */
177 for (i = 0; optlist[i]; i++) {
178 if (!strncmp(optlist[i], arg, arglen)) {
179 if (strlen(optlist[i]) == arglen)
180 /* Exact match found. */
182 else if (matchind == -1)
183 /* First nonexact match found. */
186 /* Second nonexact match found. */
197 * Error reporting for argmatch. KIND is a description of the type of entity
198 * that was being matched. VALUE is the invalid value that was given. PROBLEM
199 * is the return value from argmatch.
202 invalid_arg(const char *kind, const char *value, int problem)
204 fprintf(stderr, "patch: ");
206 fprintf(stderr, "invalid");
207 else /* Assume -2. */
208 fprintf(stderr, "ambiguous");
209 fprintf(stderr, " %s `%s'\n", kind, value);
212 static const char *backup_args[] = {
213 "never", "simple", "nil", "existing", "t", "numbered", 0
216 static enum backup_type backup_types[] = {
217 simple, simple, numbered_existing,
218 numbered_existing, numbered, numbered
222 * Return the type of backup indicated by VERSION. Unique abbreviations are
226 get_version(const char *version)
230 if (version == NULL || *version == '\0')
231 return numbered_existing;
232 i = argmatch(version, backup_args);
234 return backup_types[i];
235 invalid_arg("version control type", version, i);