builtin-update-ref.con commit show-branch -g: default to HEAD (df373ea)
   1#include "cache.h"
   2#include "refs.h"
   3#include "builtin.h"
   4
   5static const char git_update_ref_usage[] =
   6"git-update-ref [-m <reason>] (-d <refname> <value> | <refname> <value> [<oldval>])";
   7
   8int 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, delete;
  14
  15        delete = 0;
  16        setup_ident();
  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 (!strcmp("-d", argv[i])) {
  31                        delete = 1;
  32                        continue;
  33                }
  34                if (!refname) {
  35                        refname = argv[i];
  36                        continue;
  37                }
  38                if (!value) {
  39                        value = argv[i];
  40                        continue;
  41                }
  42                if (!oldval) {
  43                        oldval = argv[i];
  44                        continue;
  45                }
  46        }
  47        if (!refname || !value)
  48                usage(git_update_ref_usage);
  49
  50        if (get_sha1(value, sha1))
  51                die("%s: not a valid SHA1", value);
  52
  53        if (delete) {
  54                if (oldval)
  55                        usage(git_update_ref_usage);
  56                return delete_ref(refname, sha1);
  57        }
  58
  59        hashclr(oldsha1);
  60        if (oldval && *oldval && get_sha1(oldval, oldsha1))
  61                die("%s: not a valid old SHA1", oldval);
  62
  63        lock = lock_any_ref_for_update(refname, oldval ? oldsha1 : NULL);
  64        if (!lock)
  65                return 1;
  66        if (write_ref_sha1(lock, sha1, msg) < 0)
  67                return 1;
  68
  69        /* write_ref_sha1 always unlocks the ref, no need to do it explicitly */
  70        return 0;
  71}