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git/builtin-update-ref.c
Junio C Hamano ac5409e420 update-ref: -d flag and ref creation safety.
This adds -d flag to update-ref to allow safe deletion of ref.
Before deleting it, the command checks if the given <oldvalue>
still matches the value the caller thought the ref contained.

Similarly, it also accepts 0{40} or an empty string as <oldvalue>
to allow safe creation of a new ref.

Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-09-27 02:01:42 -07:00

72 lines
1.5 KiB
C

#include "cache.h"
#include "refs.h"
#include "builtin.h"
static const char git_update_ref_usage[] =
"git-update-ref [-m <reason>] (-d <refname> <value> | <refname> <value> [<oldval>])";
int cmd_update_ref(int argc, const char **argv, const char *prefix)
{
const char *refname=NULL, *value=NULL, *oldval=NULL, *msg=NULL;
struct ref_lock *lock;
unsigned char sha1[20], oldsha1[20];
int i, delete;
delete = 0;
setup_ident();
git_config(git_default_config);
for (i = 1; i < argc; i++) {
if (!strcmp("-m", argv[i])) {
if (i+1 >= argc)
usage(git_update_ref_usage);
msg = argv[++i];
if (!*msg)
die("Refusing to perform update with empty message.");
if (strchr(msg, '\n'))
die("Refusing to perform update with \\n in message.");
continue;
}
if (!strcmp("-d", argv[i])) {
delete = 1;
continue;
}
if (!refname) {
refname = argv[i];
continue;
}
if (!value) {
value = argv[i];
continue;
}
if (!oldval) {
oldval = argv[i];
continue;
}
}
if (!refname || !value)
usage(git_update_ref_usage);
if (get_sha1(value, sha1))
die("%s: not a valid SHA1", value);
if (delete) {
if (oldval)
usage(git_update_ref_usage);
return delete_ref(refname, sha1);
}
hashclr(oldsha1);
if (oldval && *oldval && get_sha1(oldval, oldsha1))
die("%s: not a valid old SHA1", oldval);
lock = lock_any_ref_for_update(refname, oldval ? oldsha1 : NULL);
if (!lock)
return 1;
if (write_ref_sha1(lock, sha1, msg) < 0)
return 1;
/* write_ref_sha1 always unlocks the ref, no need to do it explicitly */
return 0;
}