builtin/update-ref.c

   1 #define USE_THE_REPOSITORY_VARIABLE
   2 #define DISABLE_SIGN_COMPARE_WARNINGS
   3
   4 #include "builtin.h"
   5 #include "config.h"
   6 #include "environment.h"
   7 #include "gettext.h"
   8 #include "hash.h"
   9 #include "hex.h"
  10 #include "refs.h"
  11 #include "object-name.h"
  12 #include "parse-options.h"
  13 #include "quote.h"
  14
  15 static const char * const git_update_ref_usage[] = {
  16         N_("git update-ref [<options>] -d <refname> [<old-oid>]"),
  17         N_("git update-ref [<options>]    <refname> <new-oid> [<old-oid>]"),
  18         N_("git update-ref [<options>] --stdin [-z] [--batch-updates]"),
  19         NULL
  20 };
  21
  22 static char line_termination = '\n';
  23 static unsigned int update_flags;
  24 static unsigned int default_flags;
  25 static unsigned create_reflog_flag;
  26 static const char *msg;
  27
  28 /*
  29  * Parse one whitespace- or NUL-terminated, possibly C-quoted argument
  30  * and append the result to arg.  Return a pointer to the terminator.
  31  * Die if there is an error in how the argument is C-quoted.  This
  32  * function is only used if not -z.
  33  */
  34 static const char *parse_arg(const char *next, struct strbuf *arg)
  35 {
  36         if (*next == '"') {
  37                 const char *orig = next;
  38
  39                 if (unquote_c_style(arg, next, &next))
  40                         die("badly quoted argument: %s", orig);
  41                 if (*next && !isspace(*next))
  42                         die("unexpected character after quoted argument: %s", orig);
  43         } else {
  44                 while (*next && !isspace(*next))
  45                         strbuf_addch(arg, *next++);
  46         }
  47
  48         return next;
  49 }
  50
  51 /*
  52  * Parse the reference name immediately after "command SP".  If not
  53  * -z, then handle C-quoting.  Return a pointer to a newly allocated
  54  * string containing the name of the reference, or NULL if there was
  55  * an error.  Update *next to point at the character that terminates
  56  * the argument.  Die if C-quoting is malformed or the reference name
  57  * is invalid.
  58  */
  59 static char *parse_refname(const char **next)
  60 {
  61         struct strbuf ref = STRBUF_INIT;
  62
  63         if (line_termination) {
  64                 /* Without -z, use the next argument */
  65                 *next = parse_arg(*next, &ref);
  66         } else {
  67                 /* With -z, use everything up to the next NUL */
  68                 strbuf_addstr(&ref, *next);
  69                 *next += ref.len;
  70         }
  71
  72         if (!ref.len) {
  73                 strbuf_release(&ref);
  74                 return NULL;
  75         }
  76
  77         if (check_refname_format(ref.buf, REFNAME_ALLOW_ONELEVEL))
  78                 die("invalid ref format: %s", ref.buf);
  79
  80         return strbuf_detach(&ref, NULL);
  81 }
  82
  83 /*
  84  * Wrapper around parse_refname which skips the next delimiter.
  85  */
  86 static char *parse_next_refname(const char **next)
  87 {
  88         if (line_termination) {
  89                 /* Without -z, consume SP and use next argument */
  90                 if (!**next || **next == line_termination)
  91                         return NULL;
  92                 if (**next != ' ')
  93                         die("expected SP but got: %s", *next);
  94         } else {
  95                 /* With -z, read the next NUL-terminated line */
  96                 if (**next)
  97                         return NULL;
  98         }
  99         /* Skip the delimiter */
 100         (*next)++;
 101
 102         return parse_refname(next);
 103 }
 104
 105 /*
 106  * Wrapper around parse_arg which skips the next delimiter.
 107  */
 108 static char *parse_next_arg(const char **next)
 109 {
 110         struct strbuf arg = STRBUF_INIT;
 111
 112         if (line_termination) {
 113                 /* Without -z, consume SP and use next argument */
 114                 if (!**next || **next == line_termination)
 115                         return NULL;
 116                 if (**next != ' ')
 117                         die("expected SP but got: %s", *next);
 118         } else {
 119                 /* With -z, read the next NUL-terminated line */
 120                 if (**next)
 121                         return NULL;
 122         }
 123         /* Skip the delimiter */
 124         (*next)++;
 125
 126         if (line_termination) {
 127                 /* Without -z, use the next argument */
 128                 *next = parse_arg(*next, &arg);
 129         } else {
 130                 /* With -z, use everything up to the next NUL */
 131                 strbuf_addstr(&arg, *next);
 132                 *next += arg.len;
 133         }
 134
 135         if (arg.len)
 136                 return strbuf_detach(&arg, NULL);
 137
 138         strbuf_release(&arg);
 139         return NULL;
 140 }
 141
 142 /*
 143  * The value being parsed is <old-oid> (as opposed to <new-oid>; the
 144  * difference affects which error messages are generated):
 145  */
 146 #define PARSE_SHA1_OLD 0x01
 147
 148 /*
 149  * For backwards compatibility, accept an empty string for update's
 150  * <new-oid> in binary mode to be equivalent to specifying zeros.
 151  */
 152 #define PARSE_SHA1_ALLOW_EMPTY 0x02
 153
 154 /*
 155  * Parse an argument separator followed by the next argument, if any.
 156  * If there is an argument, convert it to a SHA-1, write it to sha1,
 157  * set *next to point at the character terminating the argument, and
 158  * return 0.  If there is no argument at all (not even the empty
 159  * string), return 1 and leave *next unchanged.  If the value is
 160  * provided but cannot be converted to a SHA-1, die.  flags can
 161  * include PARSE_SHA1_OLD and/or PARSE_SHA1_ALLOW_EMPTY.
 162  */
 163 static int parse_next_oid(const char **next, const char *end,
 164                           struct object_id *oid,
 165                           const char *command, const char *refname,
 166                           int flags)
 167 {
 168         struct strbuf arg = STRBUF_INIT;
 169         int ret = 0;
 170
 171         if (*next == end)
 172                 goto eof;
 173
 174         if (line_termination) {
 175                 /* Without -z, consume SP and use next argument */
 176                 if (!**next || **next == line_termination)
 177                         return 1;
 178                 if (**next != ' ')
 179                         die("%s %s: expected SP but got: %s",
 180                             command, refname, *next);
 181                 (*next)++;
 182                 *next = parse_arg(*next, &arg);
 183                 if (arg.len) {
 184                         if (repo_get_oid_with_flags(the_repository, arg.buf, oid,
 185                                                     GET_OID_SKIP_AMBIGUITY_CHECK))
 186                                 goto invalid;
 187                 } else {
 188                         /* Without -z, an empty value means all zeros: */
 189                         oidclr(oid, the_repository->hash_algo);
 190                 }
 191         } else {
 192                 /* With -z, read the next NUL-terminated line */
 193                 if (**next)
 194                         die("%s %s: expected NUL but got: %s",
 195                             command, refname, *next);
 196                 (*next)++;
 197                 if (*next == end)
 198                         goto eof;
 199                 strbuf_addstr(&arg, *next);
 200                 *next += arg.len;
 201
 202                 if (arg.len) {
 203                         if (repo_get_oid_with_flags(the_repository, arg.buf, oid,
 204                                                     GET_OID_SKIP_AMBIGUITY_CHECK))
 205                                 goto invalid;
 206                 } else if (flags & PARSE_SHA1_ALLOW_EMPTY) {
 207                         /* With -z, treat an empty value as all zeros: */
 208                         warning("%s %s: missing <new-oid>, treating as zero",
 209                                 command, refname);
 210                         oidclr(oid, the_repository->hash_algo);
 211                 } else {
 212                         /*
 213                          * With -z, an empty non-required value means
 214                          * unspecified:
 215                          */
 216                         ret = 1;
 217                 }
 218         }
 219
 220         strbuf_release(&arg);
 221
 222         return ret;
 223
 224  invalid:
 225         die(flags & PARSE_SHA1_OLD ?
 226             "%s %s: invalid <old-oid>: %s" :
 227             "%s %s: invalid <new-oid>: %s",
 228             command, refname, arg.buf);
 229
 230  eof:
 231         die(flags & PARSE_SHA1_OLD ?
 232             "%s %s: unexpected end of input when reading <old-oid>" :
 233             "%s %s: unexpected end of input when reading <new-oid>",
 234             command, refname);
 235 }
 236
 237
 238 /*
 239  * The following five parse_cmd_*() functions parse the corresponding
 240  * command.  In each case, next points at the character following the
 241  * command name and the following space.  They each return a pointer
 242  * to the character terminating the command, and die with an
 243  * explanatory message if there are any parsing problems.  All of
 244  * these functions handle either text or binary format input,
 245  * depending on how line_termination is set.
 246  */
 247
 248 static void parse_cmd_update(struct ref_transaction *transaction,
 249                              const char *next, const char *end)
 250 {
 251         struct strbuf err = STRBUF_INIT;
 252         char *refname;
 253         struct object_id new_oid, old_oid;
 254         int have_old;
 255
 256         refname = parse_refname(&next);
 257         if (!refname)
 258                 die("update: missing <ref>");
 259
 260         if (parse_next_oid(&next, end, &new_oid, "update", refname,
 261                            PARSE_SHA1_ALLOW_EMPTY))
 262                 die("update %s: missing <new-oid>", refname);
 263
 264         have_old = !parse_next_oid(&next, end, &old_oid, "update", refname,
 265                                    PARSE_SHA1_OLD);
 266
 267         if (*next != line_termination)
 268                 die("update %s: extra input: %s", refname, next);
 269
 270         if (ref_transaction_update(transaction, refname,
 271                                    &new_oid, have_old ? &old_oid : NULL,
 272                                    NULL, NULL,
 273                                    update_flags | create_reflog_flag,
 274                                    msg, &err))
 275                 die("%s", err.buf);
 276
 277         update_flags = default_flags;
 278         free(refname);
 279         strbuf_release(&err);
 280 }
 281
 282 static void parse_cmd_symref_update(struct ref_transaction *transaction,
 283                                     const char *next, const char *end UNUSED)
 284 {
 285         char *refname, *new_target, *old_arg;
 286         char *old_target = NULL;
 287         struct strbuf err = STRBUF_INIT;
 288         struct object_id old_oid;
 289         int have_old_oid = 0;
 290
 291         refname = parse_refname(&next);
 292         if (!refname)
 293                 die("symref-update: missing <ref>");
 294
 295         new_target = parse_next_refname(&next);
 296         if (!new_target)
 297                 die("symref-update %s: missing <new-target>", refname);
 298
 299         old_arg = parse_next_arg(&next);
 300         if (old_arg) {
 301                 old_target = parse_next_arg(&next);
 302                 if (!old_target)
 303                         die("symref-update %s: expected old value", refname);
 304
 305                 if (!strcmp(old_arg, "oid")) {
 306                         if (repo_get_oid_with_flags(the_repository, old_target, &old_oid,
 307                                                     GET_OID_SKIP_AMBIGUITY_CHECK))
 308                                 die("symref-update %s: invalid oid: %s", refname, old_target);
 309
 310                         have_old_oid = 1;
 311                 } else if (!strcmp(old_arg, "ref")) {
 312                         if (check_refname_format(old_target, REFNAME_ALLOW_ONELEVEL))
 313                                 die("symref-update %s: invalid ref: %s", refname, old_target);
 314                 } else {
 315                         die("symref-update %s: invalid arg '%s' for old value", refname, old_arg);
 316                 }
 317         }
 318
 319         if (*next != line_termination)
 320                 die("symref-update %s: extra input: %s", refname, next);
 321
 322         if (ref_transaction_update(transaction, refname, NULL,
 323                                    have_old_oid ? &old_oid : NULL,
 324                                    new_target,
 325                                    have_old_oid ? NULL : old_target,
 326                                    update_flags | create_reflog_flag,
 327                                    msg, &err))
 328                 die("%s", err.buf);
 329
 330         update_flags = default_flags;
 331         free(refname);
 332         free(old_arg);
 333         free(old_target);
 334         free(new_target);
 335         strbuf_release(&err);
 336 }
 337
 338 static void parse_cmd_create(struct ref_transaction *transaction,
 339                              const char *next, const char *end)
 340 {
 341         struct strbuf err = STRBUF_INIT;
 342         char *refname;
 343         struct object_id new_oid;
 344
 345         refname = parse_refname(&next);
 346         if (!refname)
 347                 die("create: missing <ref>");
 348
 349         if (parse_next_oid(&next, end, &new_oid, "create", refname, 0))
 350                 die("create %s: missing <new-oid>", refname);
 351
 352         if (is_null_oid(&new_oid))
 353                 die("create %s: zero <new-oid>", refname);
 354
 355         if (*next != line_termination)
 356                 die("create %s: extra input: %s", refname, next);
 357
 358         if (ref_transaction_create(transaction, refname, &new_oid, NULL,
 359                                    update_flags | create_reflog_flag,
 360                                    msg, &err))
 361                 die("%s", err.buf);
 362
 363         update_flags = default_flags;
 364         free(refname);
 365         strbuf_release(&err);
 366 }
 367
 368
 369 static void parse_cmd_symref_create(struct ref_transaction *transaction,
 370                                     const char *next, const char *end UNUSED)
 371 {
 372         struct strbuf err = STRBUF_INIT;
 373         char *refname, *new_target;
 374
 375         refname = parse_refname(&next);
 376         if (!refname)
 377                 die("symref-create: missing <ref>");
 378
 379         new_target = parse_next_refname(&next);
 380         if (!new_target)
 381                 die("symref-create %s: missing <new-target>", refname);
 382
 383         if (*next != line_termination)
 384                 die("symref-create %s: extra input: %s", refname, next);
 385
 386         if (ref_transaction_create(transaction, refname, NULL, new_target,
 387                                    update_flags | create_reflog_flag,
 388                                    msg, &err))
 389                 die("%s", err.buf);
 390
 391         update_flags = default_flags;
 392         free(refname);
 393         free(new_target);
 394         strbuf_release(&err);
 395 }
 396
 397 static void parse_cmd_delete(struct ref_transaction *transaction,
 398                              const char *next, const char *end)
 399 {
 400         struct strbuf err = STRBUF_INIT;
 401         char *refname;
 402         struct object_id old_oid;
 403         int have_old;
 404
 405         refname = parse_refname(&next);
 406         if (!refname)
 407                 die("delete: missing <ref>");
 408
 409         if (parse_next_oid(&next, end, &old_oid, "delete", refname,
 410                            PARSE_SHA1_OLD)) {
 411                 have_old = 0;
 412         } else {
 413                 if (is_null_oid(&old_oid))
 414                         die("delete %s: zero <old-oid>", refname);
 415                 have_old = 1;
 416         }
 417
 418         if (*next != line_termination)
 419                 die("delete %s: extra input: %s", refname, next);
 420
 421         if (ref_transaction_delete(transaction, refname,
 422                                    have_old ? &old_oid : NULL,
 423                                    NULL, update_flags, msg, &err))
 424                 die("%s", err.buf);
 425
 426         update_flags = default_flags;
 427         free(refname);
 428         strbuf_release(&err);
 429 }
 430
 431
 432 static void parse_cmd_symref_delete(struct ref_transaction *transaction,
 433                                     const char *next, const char *end UNUSED)
 434 {
 435         struct strbuf err = STRBUF_INIT;
 436         char *refname, *old_target;
 437
 438         if (!(update_flags & REF_NO_DEREF))
 439                 die("symref-delete: cannot operate with deref mode");
 440
 441         refname = parse_refname(&next);
 442         if (!refname)
 443                 die("symref-delete: missing <ref>");
 444
 445         old_target = parse_next_refname(&next);
 446
 447         if (*next != line_termination)
 448                 die("symref-delete %s: extra input: %s", refname, next);
 449
 450         if (ref_transaction_delete(transaction, refname, NULL,
 451                                    old_target, update_flags, msg, &err))
 452                 die("%s", err.buf);
 453
 454         update_flags = default_flags;
 455         free(refname);
 456         free(old_target);
 457         strbuf_release(&err);
 458 }
 459
 460
 461 static void parse_cmd_verify(struct ref_transaction *transaction,
 462                              const char *next, const char *end)
 463 {
 464         struct strbuf err = STRBUF_INIT;
 465         char *refname;
 466         struct object_id old_oid;
 467
 468         refname = parse_refname(&next);
 469         if (!refname)
 470                 die("verify: missing <ref>");
 471
 472         if (parse_next_oid(&next, end, &old_oid, "verify", refname,
 473                            PARSE_SHA1_OLD))
 474                 oidclr(&old_oid, the_repository->hash_algo);
 475
 476         if (*next != line_termination)
 477                 die("verify %s: extra input: %s", refname, next);
 478
 479         if (ref_transaction_verify(transaction, refname, &old_oid,
 480                                    NULL, update_flags, &err))
 481                 die("%s", err.buf);
 482
 483         update_flags = default_flags;
 484         free(refname);
 485         strbuf_release(&err);
 486 }
 487
 488 static void parse_cmd_symref_verify(struct ref_transaction *transaction,
 489                                     const char *next, const char *end UNUSED)
 490 {
 491         struct strbuf err = STRBUF_INIT;
 492         struct object_id old_oid;
 493         char *refname, *old_target;
 494
 495         if (!(update_flags & REF_NO_DEREF))
 496                 die("symref-verify: cannot operate with deref mode");
 497
 498         refname = parse_refname(&next);
 499         if (!refname)
 500                 die("symref-verify: missing <ref>");
 501
 502         /*
 503          * old_ref is optional, if not provided, we need to ensure that the
 504          * ref doesn't exist.
 505          */
 506         old_target = parse_next_refname(&next);
 507         if (!old_target)
 508                 oidcpy(&old_oid, null_oid(the_hash_algo));
 509
 510         if (*next != line_termination)
 511                 die("symref-verify %s: extra input: %s", refname, next);
 512
 513         if (ref_transaction_verify(transaction, refname,
 514                                    old_target ? NULL : &old_oid,
 515                                    old_target, update_flags, &err))
 516                 die("%s", err.buf);
 517
 518         update_flags = default_flags;
 519         free(refname);
 520         free(old_target);
 521         strbuf_release(&err);
 522 }
 523
 524 static void report_ok(const char *command)
 525 {
 526         fprintf(stdout, "%s: ok\n", command);
 527         fflush(stdout);
 528 }
 529
 530 static void parse_cmd_option(struct ref_transaction *transaction UNUSED,
 531                              const char *next, const char *end UNUSED)
 532 {
 533         const char *rest;
 534         if (skip_prefix(next, "no-deref", &rest) && *rest == line_termination)
 535                 update_flags |= REF_NO_DEREF;
 536         else
 537                 die("option unknown: %s", next);
 538 }
 539
 540 static void parse_cmd_start(struct ref_transaction *transaction UNUSED,
 541                             const char *next, const char *end UNUSED)
 542 {
 543         if (*next != line_termination)
 544                 die("start: extra input: %s", next);
 545         report_ok("start");
 546 }
 547
 548 static void parse_cmd_prepare(struct ref_transaction *transaction,
 549                               const char *next, const char *end UNUSED)
 550 {
 551         struct strbuf error = STRBUF_INIT;
 552         if (*next != line_termination)
 553                 die("prepare: extra input: %s", next);
 554         if (ref_transaction_prepare(transaction, &error))
 555                 die("prepare: %s", error.buf);
 556         report_ok("prepare");
 557 }
 558
 559 static void parse_cmd_abort(struct ref_transaction *transaction,
 560                             const char *next, const char *end UNUSED)
 561 {
 562         struct strbuf error = STRBUF_INIT;
 563         if (*next != line_termination)
 564                 die("abort: extra input: %s", next);
 565         if (ref_transaction_abort(transaction, &error))
 566                 die("abort: %s", error.buf);
 567         report_ok("abort");
 568 }
 569
 570 static void print_rejected_refs(const char *refname,
 571                                 const struct object_id *old_oid,
 572                                 const struct object_id *new_oid,
 573                                 const char *old_target,
 574                                 const char *new_target,
 575                                 enum ref_transaction_error err,
 576                                 void *cb_data UNUSED)
 577 {
 578         struct strbuf sb = STRBUF_INIT;
 579         const char *reason = ref_transaction_error_msg(err);
 580
 581         strbuf_addf(&sb, "rejected %s %s %s %s\n", refname,
 582                     new_oid ? oid_to_hex(new_oid) : new_target,
 583                     old_oid ? oid_to_hex(old_oid) : old_target,
 584                     reason);
 585
 586         fwrite(sb.buf, sb.len, 1, stdout);
 587         strbuf_release(&sb);
 588 }
 589
 590 static void parse_cmd_commit(struct ref_transaction *transaction,
 591                              const char *next, const char *end UNUSED)
 592 {
 593         struct strbuf error = STRBUF_INIT;
 594         if (*next != line_termination)
 595                 die("commit: extra input: %s", next);
 596         if (ref_transaction_commit(transaction, &error))
 597                 die("commit: %s", error.buf);
 598
 599         ref_transaction_for_each_rejected_update(transaction,
 600                                                  print_rejected_refs, NULL);
 601
 602         report_ok("commit");
 603         ref_transaction_free(transaction);
 604 }
 605
 606 enum update_refs_state {
 607         /* Non-transactional state open for updates. */
 608         UPDATE_REFS_OPEN,
 609         /* A transaction has been started. */
 610         UPDATE_REFS_STARTED,
 611         /* References are locked and ready for commit */
 612         UPDATE_REFS_PREPARED,
 613         /* Transaction has been committed or closed. */
 614         UPDATE_REFS_CLOSED,
 615 };
 616
 617 static const struct parse_cmd {
 618         const char *prefix;
 619         void (*fn)(struct ref_transaction *, const char *, const char *);
 620         unsigned args;
 621         enum update_refs_state state;
 622 } command[] = {
 623         { "update",        parse_cmd_update,        3, UPDATE_REFS_OPEN },
 624         { "create",        parse_cmd_create,        2, UPDATE_REFS_OPEN },
 625         { "delete",        parse_cmd_delete,        2, UPDATE_REFS_OPEN },
 626         { "verify",        parse_cmd_verify,        2, UPDATE_REFS_OPEN },
 627         { "symref-update", parse_cmd_symref_update, 4, UPDATE_REFS_OPEN },
 628         { "symref-create", parse_cmd_symref_create, 2, UPDATE_REFS_OPEN },
 629         { "symref-delete", parse_cmd_symref_delete, 2, UPDATE_REFS_OPEN },
 630         { "symref-verify", parse_cmd_symref_verify, 2, UPDATE_REFS_OPEN },
 631         { "option",        parse_cmd_option,        1, UPDATE_REFS_OPEN },
 632         { "start",         parse_cmd_start,         0, UPDATE_REFS_STARTED },
 633         { "prepare",       parse_cmd_prepare,       0, UPDATE_REFS_PREPARED },
 634         { "abort",         parse_cmd_abort,         0, UPDATE_REFS_CLOSED },
 635         { "commit",        parse_cmd_commit,        0, UPDATE_REFS_CLOSED },
 636 };
 637
 638 static void update_refs_stdin(unsigned int flags)
 639 {
 640         struct strbuf input = STRBUF_INIT, err = STRBUF_INIT;
 641         enum update_refs_state state = UPDATE_REFS_OPEN;
 642         struct ref_transaction *transaction;
 643         int i, j;
 644
 645         transaction = ref_store_transaction_begin(get_main_ref_store(the_repository),
 646                                                   flags, &err);
 647         if (!transaction)
 648                 die("%s", err.buf);
 649
 650         /* Read each line dispatch its command */
 651         while (!strbuf_getwholeline(&input, stdin, line_termination)) {
 652                 const struct parse_cmd *cmd = NULL;
 653
 654                 if (*input.buf == line_termination)
 655                         die("empty command in input");
 656                 else if (isspace(*input.buf))
 657                         die("whitespace before command: %s", input.buf);
 658
 659                 for (i = 0; i < ARRAY_SIZE(command); i++) {
 660                         const char *prefix = command[i].prefix;
 661                         char c;
 662
 663                         if (!starts_with(input.buf, prefix))
 664                                 continue;
 665
 666                         /*
 667                          * If the command has arguments, verify that it's
 668                          * followed by a space. Otherwise, it shall be followed
 669                          * by a line terminator.
 670                          */
 671                         c = command[i].args ? ' ' : line_termination;
 672                         if (input.buf[strlen(prefix)] != c)
 673                                 continue;
 674
 675                         cmd = &command[i];
 676                         break;
 677                 }
 678                 if (!cmd)
 679                         die("unknown command: %s", input.buf);
 680
 681                 /*
 682                  * Read additional arguments if NUL-terminated. Do not raise an
 683                  * error in case there is an early EOF to let the command
 684                  * handle missing arguments with a proper error message.
 685                  */
 686                 for (j = 1; line_termination == '\0' && j < cmd->args; j++)
 687                         if (strbuf_appendwholeline(&input, stdin, line_termination))
 688                                 break;
 689
 690                 switch (state) {
 691                 case UPDATE_REFS_OPEN:
 692                 case UPDATE_REFS_STARTED:
 693                         if (state == UPDATE_REFS_STARTED && cmd->state == UPDATE_REFS_STARTED)
 694                                 die("cannot restart ongoing transaction");
 695                         /* Do not downgrade a transaction to a non-transaction. */
 696                         if (cmd->state >= state)
 697                                 state = cmd->state;
 698                         break;
 699                 case UPDATE_REFS_PREPARED:
 700                         if (cmd->state != UPDATE_REFS_CLOSED)
 701                                 die("prepared transactions can only be closed");
 702                         state = cmd->state;
 703                         break;
 704                 case UPDATE_REFS_CLOSED:
 705                         if (cmd->state != UPDATE_REFS_STARTED)
 706                                 die("transaction is closed");
 707
 708                         /*
 709                          * Open a new transaction if we're currently closed and
 710                          * get a "start".
 711                          */
 712                         state = cmd->state;
 713                         transaction = ref_store_transaction_begin(get_main_ref_store(the_repository),
 714                                                                   flags, &err);
 715                         if (!transaction)
 716                                 die("%s", err.buf);
 717
 718                         break;
 719                 }
 720
 721                 cmd->fn(transaction, input.buf + strlen(cmd->prefix) + !!cmd->args,
 722                         input.buf + input.len);
 723         }
 724
 725         switch (state) {
 726         case UPDATE_REFS_OPEN:
 727                 /* Commit by default if no transaction was requested. */
 728                 if (ref_transaction_commit(transaction, &err))
 729                         die("%s", err.buf);
 730                 ref_transaction_for_each_rejected_update(transaction,
 731                                                  print_rejected_refs, NULL);
 732                 ref_transaction_free(transaction);
 733                 break;
 734         case UPDATE_REFS_STARTED:
 735         case UPDATE_REFS_PREPARED:
 736                 /* If using a transaction, we want to abort it. */
 737                 if (ref_transaction_abort(transaction, &err))
 738                         die("%s", err.buf);
 739                 break;
 740         case UPDATE_REFS_CLOSED:
 741                 /* Otherwise no need to do anything, the transaction was closed already. */
 742                 break;
 743         }
 744
 745         strbuf_release(&err);
 746         strbuf_release(&input);
 747 }
 748
 749 int cmd_update_ref(int argc,
 750                    const char **argv,
 751                    const char *prefix,
 752                    struct repository *repo UNUSED)
 753 {
 754         const char *refname, *oldval;
 755         struct object_id oid, oldoid;
 756         int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0;
 757         int create_reflog = 0;
 758         unsigned int flags = 0;
 759
 760         struct option options[] = {
 761                 OPT_STRING( 'm', NULL, &msg, N_("reason"), N_("reason of the update")),
 762                 OPT_BOOL('d', NULL, &delete, N_("delete the reference")),
 763                 OPT_BOOL( 0 , "no-deref", &no_deref,
 764                                         N_("update <refname> not the one it points to")),
 765                 OPT_BOOL('z', NULL, &end_null, N_("stdin has NUL-terminated arguments")),
 766                 OPT_BOOL( 0 , "stdin", &read_stdin, N_("read updates from stdin")),
 767                 OPT_BOOL( 0 , "create-reflog", &create_reflog, N_("create a reflog")),
 768                 OPT_BIT('0', "batch-updates", &flags, N_("batch reference updates"),
 769                         REF_TRANSACTION_ALLOW_FAILURE),
 770                 OPT_END(),
 771         };
 772
 773         repo_config(the_repository, git_default_config, NULL);
 774         argc = parse_options(argc, argv, prefix, options, git_update_ref_usage,
 775                              0);
 776         if (msg && !*msg)
 777                 die("Refusing to perform update with empty message.");
 778
 779         create_reflog_flag = create_reflog ? REF_FORCE_CREATE_REFLOG : 0;
 780
 781         if (no_deref) {
 782                 default_flags = REF_NO_DEREF;
 783                 update_flags = default_flags;
 784         }
 785
 786         if (read_stdin) {
 787                 if (delete || argc > 0)
 788                         usage_with_options(git_update_ref_usage, options);
 789                 if (end_null)
 790                         line_termination = '\0';
 791                 update_refs_stdin(flags);
 792                 return 0;
 793         } else if (flags & REF_TRANSACTION_ALLOW_FAILURE) {
 794                 die("--batch-updates can only be used with --stdin");
 795         }
 796
 797         if (end_null)
 798                 usage_with_options(git_update_ref_usage, options);
 799
 800         if (delete) {
 801                 if (argc < 1 || argc > 2)
 802                         usage_with_options(git_update_ref_usage, options);
 803                 refname = argv[0];
 804                 oldval = argv[1];
 805         } else {
 806                 const char *value;
 807                 if (argc < 2 || argc > 3)
 808                         usage_with_options(git_update_ref_usage, options);
 809                 refname = argv[0];
 810                 value = argv[1];
 811                 oldval = argv[2];
 812                 if (repo_get_oid_with_flags(the_repository, value, &oid,
 813                                             GET_OID_SKIP_AMBIGUITY_CHECK))
 814                         die("%s: not a valid SHA1", value);
 815         }
 816
 817         if (oldval) {
 818                 if (!*oldval)
 819                         /*
 820                          * The empty string implies that the reference
 821                          * must not already exist:
 822                          */
 823                         oidclr(&oldoid, the_repository->hash_algo);
 824                 else if (repo_get_oid_with_flags(the_repository, oldval, &oldoid,
 825                                                  GET_OID_SKIP_AMBIGUITY_CHECK))
 826                         die("%s: not a valid old SHA1", oldval);
 827         }
 828
 829         if (delete)
 830                 /*
 831                  * For purposes of backwards compatibility, we treat
 832                  * NULL_SHA1 as "don't care" here:
 833                  */
 834                 return refs_delete_ref(get_main_ref_store(the_repository),
 835                                        msg, refname,
 836                                        (oldval && !is_null_oid(&oldoid)) ? &oldoid : NULL,
 837                                        default_flags);
 838         else
 839                 return refs_update_ref(get_main_ref_store(the_repository),
 840                                        msg, refname, &oid,
 841                                        oldval ? &oldoid : NULL,
 842                                        default_flags | create_reflog_flag,
 843                                        UPDATE_REFS_DIE_ON_ERR);
 844 }