builtin/update-ref.c

   1 #include "cache.h"
   2 #include "config.h"
   3 #include "gettext.h"
   4 #include "hash.h"
   5 #include "refs.h"
   6 #include "builtin.h"
   7 #include "object-name.h"
   8 #include "parse-options.h"
   9 #include "quote.h"
  10 #include "repository.h"
  11 #include "strvec.h"
  12
  13 static const char * const git_update_ref_usage[] = {
  14         N_("git update-ref [<options>] -d <refname> [<old-val>]"),
  15         N_("git update-ref [<options>]    <refname> <new-val> [<old-val>]"),
  16         N_("git update-ref [<options>] --stdin [-z]"),
  17         NULL
  18 };
  19
  20 static char line_termination = '\n';
  21 static unsigned int update_flags;
  22 static unsigned int default_flags;
  23 static unsigned create_reflog_flag;
  24 static const char *msg;
  25
  26 /*
  27  * Parse one whitespace- or NUL-terminated, possibly C-quoted argument
  28  * and append the result to arg.  Return a pointer to the terminator.
  29  * Die if there is an error in how the argument is C-quoted.  This
  30  * function is only used if not -z.
  31  */
  32 static const char *parse_arg(const char *next, struct strbuf *arg)
  33 {
  34         if (*next == '"') {
  35                 const char *orig = next;
  36
  37                 if (unquote_c_style(arg, next, &next))
  38                         die("badly quoted argument: %s", orig);
  39                 if (*next && !isspace(*next))
  40                         die("unexpected character after quoted argument: %s", orig);
  41         } else {
  42                 while (*next && !isspace(*next))
  43                         strbuf_addch(arg, *next++);
  44         }
  45
  46         return next;
  47 }
  48
  49 /*
  50  * Parse the reference name immediately after "command SP".  If not
  51  * -z, then handle C-quoting.  Return a pointer to a newly allocated
  52  * string containing the name of the reference, or NULL if there was
  53  * an error.  Update *next to point at the character that terminates
  54  * the argument.  Die if C-quoting is malformed or the reference name
  55  * is invalid.
  56  */
  57 static char *parse_refname(const char **next)
  58 {
  59         struct strbuf ref = STRBUF_INIT;
  60
  61         if (line_termination) {
  62                 /* Without -z, use the next argument */
  63                 *next = parse_arg(*next, &ref);
  64         } else {
  65                 /* With -z, use everything up to the next NUL */
  66                 strbuf_addstr(&ref, *next);
  67                 *next += ref.len;
  68         }
  69
  70         if (!ref.len) {
  71                 strbuf_release(&ref);
  72                 return NULL;
  73         }
  74
  75         if (check_refname_format(ref.buf, REFNAME_ALLOW_ONELEVEL))
  76                 die("invalid ref format: %s", ref.buf);
  77
  78         return strbuf_detach(&ref, NULL);
  79 }
  80
  81 /*
  82  * The value being parsed is <oldvalue> (as opposed to <newvalue>; the
  83  * difference affects which error messages are generated):
  84  */
  85 #define PARSE_SHA1_OLD 0x01
  86
  87 /*
  88  * For backwards compatibility, accept an empty string for update's
  89  * <newvalue> in binary mode to be equivalent to specifying zeros.
  90  */
  91 #define PARSE_SHA1_ALLOW_EMPTY 0x02
  92
  93 /*
  94  * Parse an argument separator followed by the next argument, if any.
  95  * If there is an argument, convert it to a SHA-1, write it to sha1,
  96  * set *next to point at the character terminating the argument, and
  97  * return 0.  If there is no argument at all (not even the empty
  98  * string), return 1 and leave *next unchanged.  If the value is
  99  * provided but cannot be converted to a SHA-1, die.  flags can
 100  * include PARSE_SHA1_OLD and/or PARSE_SHA1_ALLOW_EMPTY.
 101  */
 102 static int parse_next_oid(const char **next, const char *end,
 103                           struct object_id *oid,
 104                           const char *command, const char *refname,
 105                           int flags)
 106 {
 107         struct strbuf arg = STRBUF_INIT;
 108         int ret = 0;
 109
 110         if (*next == end)
 111                 goto eof;
 112
 113         if (line_termination) {
 114                 /* Without -z, consume SP and use next argument */
 115                 if (!**next || **next == line_termination)
 116                         return 1;
 117                 if (**next != ' ')
 118                         die("%s %s: expected SP but got: %s",
 119                             command, refname, *next);
 120                 (*next)++;
 121                 *next = parse_arg(*next, &arg);
 122                 if (arg.len) {
 123                         if (repo_get_oid(the_repository, arg.buf, oid))
 124                                 goto invalid;
 125                 } else {
 126                         /* Without -z, an empty value means all zeros: */
 127                         oidclr(oid);
 128                 }
 129         } else {
 130                 /* With -z, read the next NUL-terminated line */
 131                 if (**next)
 132                         die("%s %s: expected NUL but got: %s",
 133                             command, refname, *next);
 134                 (*next)++;
 135                 if (*next == end)
 136                         goto eof;
 137                 strbuf_addstr(&arg, *next);
 138                 *next += arg.len;
 139
 140                 if (arg.len) {
 141                         if (repo_get_oid(the_repository, arg.buf, oid))
 142                                 goto invalid;
 143                 } else if (flags & PARSE_SHA1_ALLOW_EMPTY) {
 144                         /* With -z, treat an empty value as all zeros: */
 145                         warning("%s %s: missing <newvalue>, treating as zero",
 146                                 command, refname);
 147                         oidclr(oid);
 148                 } else {
 149                         /*
 150                          * With -z, an empty non-required value means
 151                          * unspecified:
 152                          */
 153                         ret = 1;
 154                 }
 155         }
 156
 157         strbuf_release(&arg);
 158
 159         return ret;
 160
 161  invalid:
 162         die(flags & PARSE_SHA1_OLD ?
 163             "%s %s: invalid <oldvalue>: %s" :
 164             "%s %s: invalid <newvalue>: %s",
 165             command, refname, arg.buf);
 166
 167  eof:
 168         die(flags & PARSE_SHA1_OLD ?
 169             "%s %s: unexpected end of input when reading <oldvalue>" :
 170             "%s %s: unexpected end of input when reading <newvalue>",
 171             command, refname);
 172 }
 173
 174
 175 /*
 176  * The following five parse_cmd_*() functions parse the corresponding
 177  * command.  In each case, next points at the character following the
 178  * command name and the following space.  They each return a pointer
 179  * to the character terminating the command, and die with an
 180  * explanatory message if there are any parsing problems.  All of
 181  * these functions handle either text or binary format input,
 182  * depending on how line_termination is set.
 183  */
 184
 185 static void parse_cmd_update(struct ref_transaction *transaction,
 186                              const char *next, const char *end)
 187 {
 188         struct strbuf err = STRBUF_INIT;
 189         char *refname;
 190         struct object_id new_oid, old_oid;
 191         int have_old;
 192
 193         refname = parse_refname(&next);
 194         if (!refname)
 195                 die("update: missing <ref>");
 196
 197         if (parse_next_oid(&next, end, &new_oid, "update", refname,
 198                            PARSE_SHA1_ALLOW_EMPTY))
 199                 die("update %s: missing <newvalue>", refname);
 200
 201         have_old = !parse_next_oid(&next, end, &old_oid, "update", refname,
 202                                    PARSE_SHA1_OLD);
 203
 204         if (*next != line_termination)
 205                 die("update %s: extra input: %s", refname, next);
 206
 207         if (ref_transaction_update(transaction, refname,
 208                                    &new_oid, have_old ? &old_oid : NULL,
 209                                    update_flags | create_reflog_flag,
 210                                    msg, &err))
 211                 die("%s", err.buf);
 212
 213         update_flags = default_flags;
 214         free(refname);
 215         strbuf_release(&err);
 216 }
 217
 218 static void parse_cmd_create(struct ref_transaction *transaction,
 219                              const char *next, const char *end)
 220 {
 221         struct strbuf err = STRBUF_INIT;
 222         char *refname;
 223         struct object_id new_oid;
 224
 225         refname = parse_refname(&next);
 226         if (!refname)
 227                 die("create: missing <ref>");
 228
 229         if (parse_next_oid(&next, end, &new_oid, "create", refname, 0))
 230                 die("create %s: missing <newvalue>", refname);
 231
 232         if (is_null_oid(&new_oid))
 233                 die("create %s: zero <newvalue>", refname);
 234
 235         if (*next != line_termination)
 236                 die("create %s: extra input: %s", refname, next);
 237
 238         if (ref_transaction_create(transaction, refname, &new_oid,
 239                                    update_flags | create_reflog_flag,
 240                                    msg, &err))
 241                 die("%s", err.buf);
 242
 243         update_flags = default_flags;
 244         free(refname);
 245         strbuf_release(&err);
 246 }
 247
 248 static void parse_cmd_delete(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 old_oid;
 254         int have_old;
 255
 256         refname = parse_refname(&next);
 257         if (!refname)
 258                 die("delete: missing <ref>");
 259
 260         if (parse_next_oid(&next, end, &old_oid, "delete", refname,
 261                            PARSE_SHA1_OLD)) {
 262                 have_old = 0;
 263         } else {
 264                 if (is_null_oid(&old_oid))
 265                         die("delete %s: zero <oldvalue>", refname);
 266                 have_old = 1;
 267         }
 268
 269         if (*next != line_termination)
 270                 die("delete %s: extra input: %s", refname, next);
 271
 272         if (ref_transaction_delete(transaction, refname,
 273                                    have_old ? &old_oid : NULL,
 274                                    update_flags, 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_verify(struct ref_transaction *transaction,
 283                              const char *next, const char *end)
 284 {
 285         struct strbuf err = STRBUF_INIT;
 286         char *refname;
 287         struct object_id old_oid;
 288
 289         refname = parse_refname(&next);
 290         if (!refname)
 291                 die("verify: missing <ref>");
 292
 293         if (parse_next_oid(&next, end, &old_oid, "verify", refname,
 294                            PARSE_SHA1_OLD))
 295                 oidclr(&old_oid);
 296
 297         if (*next != line_termination)
 298                 die("verify %s: extra input: %s", refname, next);
 299
 300         if (ref_transaction_verify(transaction, refname, &old_oid,
 301                                    update_flags, &err))
 302                 die("%s", err.buf);
 303
 304         update_flags = default_flags;
 305         free(refname);
 306         strbuf_release(&err);
 307 }
 308
 309 static void report_ok(const char *command)
 310 {
 311         fprintf(stdout, "%s: ok\n", command);
 312         fflush(stdout);
 313 }
 314
 315 static void parse_cmd_option(struct ref_transaction *transaction,
 316                              const char *next, const char *end)
 317 {
 318         const char *rest;
 319         if (skip_prefix(next, "no-deref", &rest) && *rest == line_termination)
 320                 update_flags |= REF_NO_DEREF;
 321         else
 322                 die("option unknown: %s", next);
 323 }
 324
 325 static void parse_cmd_start(struct ref_transaction *transaction,
 326                             const char *next, const char *end)
 327 {
 328         if (*next != line_termination)
 329                 die("start: extra input: %s", next);
 330         report_ok("start");
 331 }
 332
 333 static void parse_cmd_prepare(struct ref_transaction *transaction,
 334                               const char *next, const char *end)
 335 {
 336         struct strbuf error = STRBUF_INIT;
 337         if (*next != line_termination)
 338                 die("prepare: extra input: %s", next);
 339         if (ref_transaction_prepare(transaction, &error))
 340                 die("prepare: %s", error.buf);
 341         report_ok("prepare");
 342 }
 343
 344 static void parse_cmd_abort(struct ref_transaction *transaction,
 345                             const char *next, const char *end)
 346 {
 347         struct strbuf error = STRBUF_INIT;
 348         if (*next != line_termination)
 349                 die("abort: extra input: %s", next);
 350         if (ref_transaction_abort(transaction, &error))
 351                 die("abort: %s", error.buf);
 352         report_ok("abort");
 353 }
 354
 355 static void parse_cmd_commit(struct ref_transaction *transaction,
 356                              const char *next, const char *end)
 357 {
 358         struct strbuf error = STRBUF_INIT;
 359         if (*next != line_termination)
 360                 die("commit: extra input: %s", next);
 361         if (ref_transaction_commit(transaction, &error))
 362                 die("commit: %s", error.buf);
 363         report_ok("commit");
 364         ref_transaction_free(transaction);
 365 }
 366
 367 enum update_refs_state {
 368         /* Non-transactional state open for updates. */
 369         UPDATE_REFS_OPEN,
 370         /* A transaction has been started. */
 371         UPDATE_REFS_STARTED,
 372         /* References are locked and ready for commit */
 373         UPDATE_REFS_PREPARED,
 374         /* Transaction has been committed or closed. */
 375         UPDATE_REFS_CLOSED,
 376 };
 377
 378 static const struct parse_cmd {
 379         const char *prefix;
 380         void (*fn)(struct ref_transaction *, const char *, const char *);
 381         unsigned args;
 382         enum update_refs_state state;
 383 } command[] = {
 384         { "update",  parse_cmd_update,  3, UPDATE_REFS_OPEN },
 385         { "create",  parse_cmd_create,  2, UPDATE_REFS_OPEN },
 386         { "delete",  parse_cmd_delete,  2, UPDATE_REFS_OPEN },
 387         { "verify",  parse_cmd_verify,  2, UPDATE_REFS_OPEN },
 388         { "option",  parse_cmd_option,  1, UPDATE_REFS_OPEN },
 389         { "start",   parse_cmd_start,   0, UPDATE_REFS_STARTED },
 390         { "prepare", parse_cmd_prepare, 0, UPDATE_REFS_PREPARED },
 391         { "abort",   parse_cmd_abort,   0, UPDATE_REFS_CLOSED },
 392         { "commit",  parse_cmd_commit,  0, UPDATE_REFS_CLOSED },
 393 };
 394
 395 static void update_refs_stdin(void)
 396 {
 397         struct strbuf input = STRBUF_INIT, err = STRBUF_INIT;
 398         enum update_refs_state state = UPDATE_REFS_OPEN;
 399         struct ref_transaction *transaction;
 400         int i, j;
 401
 402         transaction = ref_transaction_begin(&err);
 403         if (!transaction)
 404                 die("%s", err.buf);
 405
 406         /* Read each line dispatch its command */
 407         while (!strbuf_getwholeline(&input, stdin, line_termination)) {
 408                 const struct parse_cmd *cmd = NULL;
 409
 410                 if (*input.buf == line_termination)
 411                         die("empty command in input");
 412                 else if (isspace(*input.buf))
 413                         die("whitespace before command: %s", input.buf);
 414
 415                 for (i = 0; i < ARRAY_SIZE(command); i++) {
 416                         const char *prefix = command[i].prefix;
 417                         char c;
 418
 419                         if (!starts_with(input.buf, prefix))
 420                                 continue;
 421
 422                         /*
 423                          * If the command has arguments, verify that it's
 424                          * followed by a space. Otherwise, it shall be followed
 425                          * by a line terminator.
 426                          */
 427                         c = command[i].args ? ' ' : line_termination;
 428                         if (input.buf[strlen(prefix)] != c)
 429                                 continue;
 430
 431                         cmd = &command[i];
 432                         break;
 433                 }
 434                 if (!cmd)
 435                         die("unknown command: %s", input.buf);
 436
 437                 /*
 438                  * Read additional arguments if NUL-terminated. Do not raise an
 439                  * error in case there is an early EOF to let the command
 440                  * handle missing arguments with a proper error message.
 441                  */
 442                 for (j = 1; line_termination == '\0' && j < cmd->args; j++)
 443                         if (strbuf_appendwholeline(&input, stdin, line_termination))
 444                                 break;
 445
 446                 switch (state) {
 447                 case UPDATE_REFS_OPEN:
 448                 case UPDATE_REFS_STARTED:
 449                         if (state == UPDATE_REFS_STARTED && cmd->state == UPDATE_REFS_STARTED)
 450                                 die("cannot restart ongoing transaction");
 451                         /* Do not downgrade a transaction to a non-transaction. */
 452                         if (cmd->state >= state)
 453                                 state = cmd->state;
 454                         break;
 455                 case UPDATE_REFS_PREPARED:
 456                         if (cmd->state != UPDATE_REFS_CLOSED)
 457                                 die("prepared transactions can only be closed");
 458                         state = cmd->state;
 459                         break;
 460                 case UPDATE_REFS_CLOSED:
 461                         if (cmd->state != UPDATE_REFS_STARTED)
 462                                 die("transaction is closed");
 463
 464                         /*
 465                          * Open a new transaction if we're currently closed and
 466                          * get a "start".
 467                          */
 468                         state = cmd->state;
 469                         transaction = ref_transaction_begin(&err);
 470                         if (!transaction)
 471                                 die("%s", err.buf);
 472
 473                         break;
 474                 }
 475
 476                 cmd->fn(transaction, input.buf + strlen(cmd->prefix) + !!cmd->args,
 477                         input.buf + input.len);
 478         }
 479
 480         switch (state) {
 481         case UPDATE_REFS_OPEN:
 482                 /* Commit by default if no transaction was requested. */
 483                 if (ref_transaction_commit(transaction, &err))
 484                         die("%s", err.buf);
 485                 ref_transaction_free(transaction);
 486                 break;
 487         case UPDATE_REFS_STARTED:
 488         case UPDATE_REFS_PREPARED:
 489                 /* If using a transaction, we want to abort it. */
 490                 if (ref_transaction_abort(transaction, &err))
 491                         die("%s", err.buf);
 492                 break;
 493         case UPDATE_REFS_CLOSED:
 494                 /* Otherwise no need to do anything, the transaction was closed already. */
 495                 break;
 496         }
 497
 498         strbuf_release(&err);
 499         strbuf_release(&input);
 500 }
 501
 502 int cmd_update_ref(int argc, const char **argv, const char *prefix)
 503 {
 504         const char *refname, *oldval;
 505         struct object_id oid, oldoid;
 506         int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0;
 507         int create_reflog = 0;
 508         struct option options[] = {
 509                 OPT_STRING( 'm', NULL, &msg, N_("reason"), N_("reason of the update")),
 510                 OPT_BOOL('d', NULL, &delete, N_("delete the reference")),
 511                 OPT_BOOL( 0 , "no-deref", &no_deref,
 512                                         N_("update <refname> not the one it points to")),
 513                 OPT_BOOL('z', NULL, &end_null, N_("stdin has NUL-terminated arguments")),
 514                 OPT_BOOL( 0 , "stdin", &read_stdin, N_("read updates from stdin")),
 515                 OPT_BOOL( 0 , "create-reflog", &create_reflog, N_("create a reflog")),
 516                 OPT_END(),
 517         };
 518
 519         git_config(git_default_config, NULL);
 520         argc = parse_options(argc, argv, prefix, options, git_update_ref_usage,
 521                              0);
 522         if (msg && !*msg)
 523                 die("Refusing to perform update with empty message.");
 524
 525         create_reflog_flag = create_reflog ? REF_FORCE_CREATE_REFLOG : 0;
 526
 527         if (no_deref) {
 528                 default_flags = REF_NO_DEREF;
 529                 update_flags = default_flags;
 530         }
 531
 532         if (read_stdin) {
 533                 if (delete || argc > 0)
 534                         usage_with_options(git_update_ref_usage, options);
 535                 if (end_null)
 536                         line_termination = '\0';
 537                 update_refs_stdin();
 538                 return 0;
 539         }
 540
 541         if (end_null)
 542                 usage_with_options(git_update_ref_usage, options);
 543
 544         if (delete) {
 545                 if (argc < 1 || argc > 2)
 546                         usage_with_options(git_update_ref_usage, options);
 547                 refname = argv[0];
 548                 oldval = argv[1];
 549         } else {
 550                 const char *value;
 551                 if (argc < 2 || argc > 3)
 552                         usage_with_options(git_update_ref_usage, options);
 553                 refname = argv[0];
 554                 value = argv[1];
 555                 oldval = argv[2];
 556                 if (repo_get_oid(the_repository, value, &oid))
 557                         die("%s: not a valid SHA1", value);
 558         }
 559
 560         if (oldval) {
 561                 if (!*oldval)
 562                         /*
 563                          * The empty string implies that the reference
 564                          * must not already exist:
 565                          */
 566                         oidclr(&oldoid);
 567                 else if (repo_get_oid(the_repository, oldval, &oldoid))
 568                         die("%s: not a valid old SHA1", oldval);
 569         }
 570
 571         if (delete)
 572                 /*
 573                  * For purposes of backwards compatibility, we treat
 574                  * NULL_SHA1 as "don't care" here:
 575                  */
 576                 return delete_ref(msg, refname,
 577                                   (oldval && !is_null_oid(&oldoid)) ? &oldoid : NULL,
 578                                   default_flags);
 579         else
 580                 return update_ref(msg, refname, &oid, oldval ? &oldoid : NULL,
 581                                   default_flags | create_reflog_flag,
 582                                   UPDATE_REFS_DIE_ON_ERR);
 583 }