summaryrefslogtreecommitdiffabout
path: root/src/backup.c
Side-by-side diff
Diffstat (limited to 'src/backup.c') (more/less context) (ignore whitespace changes)
-rw-r--r--src/backup.c165
1 files changed, 165 insertions, 0 deletions
diff --git a/src/backup.c b/src/backup.c
new file mode 100644
index 0000000..312375d
--- a/dev/null
+++ b/src/backup.c
@@ -0,0 +1,165 @@
+/* wydawca - automatic release submission daemon
+ Copyright (C) 2011 Sergey Poznyakoff
+
+ Wydawca 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.
+
+ Wydawca 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 wydawca. If not, see <http://www.gnu.org/licenses/>. */
+
+#include "wydawca.h"
+
+char const *simple_backup_suffix = "~";
+
+static const char *
+split_filename (char const *file, char **pdir)
+{
+ const char *p = strrchr (file, '/');
+
+ if (!p)
+ {
+ *pdir = grecs_strdup (".");
+ p = file;
+ }
+ else
+ {
+ size_t len = p - file;
+ char *dir = grecs_malloc (len + 1);
+ memcpy (dir, file, len);
+ dir[len] = 0;
+ *pdir = dir;
+ p++;
+ }
+ return p;
+}
+
+#define MINSUFSIZE 8
+#define ISDIGIT(c) ('0' <= (c) && (c) <= '9')
+
+static char *
+get_backup_suffix (char const *file, enum backup_type type)
+{
+ char *dirname;
+ const char *basename;
+ size_t baselen;
+ DIR *dir;
+ struct dirent *ent;
+ char *lastsuf = NULL;
+ size_t lastsuflen = 0;
+ size_t lastsufsize = 0;
+ int carry;
+ char *newsuf;
+ char *q;
+
+ if (type == simple_backups)
+ return grecs_strdup (simple_backup_suffix);
+
+ basename = split_filename (file, &dirname);
+ baselen = strlen (basename);
+ dir = opendir (dirname);
+ if (!dir)
+ {
+ int ec = errno;
+ free (dirname);
+ errno = ec;
+ return NULL;
+ }
+
+ while ((ent = readdir (dir)))
+ {
+ size_t len = strlen (ent->d_name);
+ const char *p;
+ size_t suflen;
+
+ if (len < baselen + 4 || memcmp (ent->d_name, basename, baselen))
+ continue;
+ p = ent->d_name + baselen;
+ suflen = len - baselen;
+ if (p[0] == '.' && p[1] == '~' && p[suflen-1] == '~' &&
+ (suflen > lastsuflen
+ || (suflen == lastsuflen &&
+ memcmp (p, lastsuf, lastsuflen) > 0)))
+ {
+ carry = 1;
+ for (q = (char*) p + suflen - 2; q > p + 1 && ISDIGIT (*q); q--)
+ if (*q != '9')
+ carry = 0;
+ q++;
+ if (!ISDIGIT (*q))
+ continue;
+
+ if (suflen > lastsufsize)
+ {
+ lastsufsize = suflen;
+ if (!lastsuf)
+ {
+ if (lastsufsize < MINSUFSIZE)
+ lastsufsize = MINSUFSIZE;
+ lastsuf = grecs_malloc (lastsufsize);
+ }
+ else
+ lastsuf = grecs_realloc (lastsuf, lastsufsize);
+ }
+ memcpy (lastsuf, p, suflen);
+ lastsuflen = suflen;
+ }
+ }
+ closedir (dir);
+ free (dirname);
+
+ if (lastsuf)
+ {
+ size_t newsuflen;
+
+ newsuflen = lastsuflen + carry;
+ newsuf = grecs_malloc (newsuflen + 1);
+ newsuf[0] = '.';
+ newsuf[1] = '~';
+ newsuf[2] = '0';
+ memcpy (newsuf + 2 + carry, lastsuf + 2, lastsuflen - 3);
+ newsuf[newsuflen-1] = '~';
+ newsuf[newsuflen] = 0;
+
+ for (q = newsuf + newsuflen - 2; *q == '9'; q--)
+ *q = '0';
+ ++*q;
+ free (lastsuf);
+ }
+ else if (type == numbered_existing_backups)
+ newsuf = grecs_strdup (simple_backup_suffix);
+ else
+ newsuf = grecs_strdup (".~1~");
+ return newsuf;
+}
+
+char *
+find_backup_file_name (char const *file, enum backup_type type)
+{
+ size_t flen;
+ char *suffix;
+ char *newname;
+
+ if (type == no_backups)
+ {
+ errno = 0;
+ return NULL;
+ }
+
+ suffix = get_backup_suffix (file, type);
+ if (!suffix)
+ return NULL;
+ flen = strlen (file);
+ newname = grecs_malloc (flen + strlen (suffix) + 1);
+ memcpy (newname, file, flen);
+ strcpy (newname + flen, suffix);
+ free (suffix);
+ /* FIXME: Check newname length */
+ return newname;
+}

Return to:

Send suggestions and report system problems to the System administrator.