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, const char *prefix)
   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         git_config(git_default_config);
  17
  18         for (i = 1; i < argc; i++) {
  19                 if (!strcmp("-m", argv[i])) {
  20                         if (i+1 >= argc)
  21                                 usage(git_update_ref_usage);
  22                         msg = argv[++i];
  23                         if (!*msg)
  24                                 die("Refusing to perform update with empty message.");
  25                         if (strchr(msg, '\n'))
  26                                 die("Refusing to perform update with \\n in message.");
  27                         continue;
  28                 }
  29                 if (!refname) {
  30                         refname = argv[i];
  31                         continue;
  32                 }
  33                 if (!value) {
  34                         value = argv[i];
  35                         continue;
  36                 }
  37                 if (!oldval) {
  38                         oldval = argv[i];
  39                         continue;
  40                 }
  41         }
  42         if (!refname || !value)
  43                 usage(git_update_ref_usage);
  44
  45         if (get_sha1(value, sha1))
  46                 die("%s: not a valid SHA1", value);
  47         memset(oldsha1, 0, 20);
  48         if (oldval && get_sha1(oldval, oldsha1))
  49                 die("%s: not a valid old SHA1", oldval);
  50
  51         lock = lock_any_ref_for_update(refname, oldval ? oldsha1 : NULL, 0);
  52         if (!lock)
  53                 return 1;
  54         if (write_ref_sha1(lock, sha1, msg) < 0)
  55                 return 1;
  56
  57         /* write_ref_sha1 always unlocks the ref, no need to do it explicitly */
  58         return 0;
  59 }