Merge branch 'js/merge-base'
[git] / builtin-update-ref.c
1 #include "cache.h"
2 #include "refs.h"
3 #include "builtin.h"
4
5 static const char git_update_ref_usage[] =
6 "git-update-ref <refname> <value> [<oldval>] [-m <reason>]";
7
8 int cmd_update_ref(int argc, const char **argv, char **envp)
9 {
10         const char *refname=NULL, *value=NULL, *oldval=NULL, *msg=NULL;
11         struct ref_lock *lock;
12         unsigned char sha1[20], oldsha1[20];
13         int i;
14
15         setup_ident();
16         setup_git_directory();
17         git_config(git_default_config);
18
19         for (i = 1; i < argc; i++) {
20                 if (!strcmp("-m", argv[i])) {
21                         if (i+1 >= argc)
22                                 usage(git_update_ref_usage);
23                         msg = argv[++i];
24                         if (!*msg)
25                                 die("Refusing to perform update with empty message.");
26                         if (strchr(msg, '\n'))
27                                 die("Refusing to perform update with \\n in message.");
28                         continue;
29                 }
30                 if (!refname) {
31                         refname = argv[i];
32                         continue;
33                 }
34                 if (!value) {
35                         value = argv[i];
36                         continue;
37                 }
38                 if (!oldval) {
39                         oldval = argv[i];
40                         continue;
41                 }
42         }
43         if (!refname || !value)
44                 usage(git_update_ref_usage);
45
46         if (get_sha1(value, sha1))
47                 die("%s: not a valid SHA1", value);
48         memset(oldsha1, 0, 20);
49         if (oldval && get_sha1(oldval, oldsha1))
50                 die("%s: not a valid old SHA1", oldval);
51
52         lock = lock_any_ref_for_update(refname, oldval ? oldsha1 : NULL, 0);
53         if (!lock)
54                 return 1;
55         if (write_ref_sha1(lock, sha1, msg) < 0)
56                 return 1;
57
58         /* write_ref_sha1 always unlocks the ref, no need to do it explicitly */
59         return 0;
60 }