update-ref.con commit Merge git://git.kernel.org/pub/scm/gitk/gitk (7fb23e6)
   1#include "cache.h"
   2#include "refs.h"
   3
   4static const char git_update_ref_usage[] =
   5"git-update-ref <refname> <value> [<oldval>] [-m <reason>]";
   6
   7int main(int argc, char **argv)
   8{
   9        const char *refname=NULL, *value=NULL, *oldval=NULL, *msg=NULL;
  10        struct ref_lock *lock;
  11        unsigned char sha1[20], oldsha1[20];
  12        int i;
  13
  14        setup_git_directory();
  15        git_config(git_default_config);
  16
  17        for (i = 1; i < argc; i++) {
  18                if (!strcmp("-m", argv[i])) {
  19                        if (i+1 >= argc)
  20                                usage(git_update_ref_usage);
  21                        msg = argv[++i];
  22                        if (!*msg)
  23                                die("Refusing to perform update with empty message.");
  24                        if (strchr(msg, '\n'))
  25                                die("Refusing to perform update with \\n in message.");
  26                        continue;
  27                }
  28                if (!refname) {
  29                        refname = argv[i];
  30                        continue;
  31                }
  32                if (!value) {
  33                        value = argv[i];
  34                        continue;
  35                }
  36                if (!oldval) {
  37                        oldval = argv[i];
  38                        continue;
  39                }
  40        }
  41        if (!refname || !value)
  42                usage(git_update_ref_usage);
  43
  44        if (get_sha1(value, sha1))
  45                die("%s: not a valid SHA1", value);
  46        memset(oldsha1, 0, 20);
  47        if (oldval && get_sha1(oldval, oldsha1))
  48                die("%s: not a valid old SHA1", oldval);
  49
  50        lock = lock_any_ref_for_update(refname, oldval ? oldsha1 : NULL, 0);
  51        if (!lock)
  52                return 1;
  53        if (write_ref_sha1(lock, sha1, msg) < 0)
  54                return 1;
  55        return 0;
  56}