builtin/update-ref.c

   1 #include "cache.h"
   2 #include "config.h"
   3 #include "gettext.h"
   4 #include "refs.h"
   5 #include "builtin.h"
   6 #include "parse-options.h"
   7 #include "quote.h"
   8 #include "strvec.h"
   9
  10 static const char * const git_update_ref_usage[] = {
  11         N_("git update-ref [<options>] -d <refname> [<old-val>]"),
  12         N_("git update-ref [<options>]    <refname> <new-val> [<old-val>]"),
  13         N_("git update-ref [<options>] --stdin [-z]"),
  14         NULL
  15 };
  16
  17 static char line_termination = '\n';
  18 static unsigned int update_flags;
  19 static unsigned int default_flags;
  20 static unsigned create_reflog_flag;
  21 static const char *msg;
  22
  23 /*
  24  * Parse one whitespace- or NUL-terminated, possibly C-quoted argument
  25  * and append the result to arg.  Return a pointer to the terminator.
  26  * Die if there is an error in how the argument is C-quoted.  This
  27  * function is only used if not -z.
  28  */
  29 static const char *parse_arg(const char *next, struct strbuf *arg)
  30 {
  31         if (*next == '"') {
  32                 const char *orig = next;
  33
  34                 if (unquote_c_style(arg, next, &next))
  35                         die("badly quoted argument: %s", orig);
  36                 if (*next && !isspace(*next))
  37                         die("unexpected character after quoted argument: %s", orig);
  38         } else {
  39                 while (*next && !isspace(*next))
  40                         strbuf_addch(arg, *next++);
  41         }
  42
  43         return next;
  44 }
  45
  46 /*
  47  * Parse the reference name immediately after "command SP".  If not
  48  * -z, then handle C-quoting.  Return a pointer to a newly allocated
  49  * string containing the name of the reference, or NULL if there was
  50  * an error.  Update *next to point at the character that terminates
  51  * the argument.  Die if C-quoting is malformed or the reference name
  52  * is invalid.
  53  */
  54 static char *parse_refname(const char **next)
  55 {
  56         struct strbuf ref = STRBUF_INIT;
  57
  58         if (line_termination) {
  59                 /* Without -z, use the next argument */
  60                 *next = parse_arg(*next, &ref);
  61         } else {
  62                 /* With -z, use everything up to the next NUL */
  63                 strbuf_addstr(&ref, *next);
  64                 *next += ref.len;
  65         }
  66
  67         if (!ref.len) {
  68                 strbuf_release(&ref);
  69                 return NULL;
  70         }
  71
  72         if (check_refname_format(ref.buf, REFNAME_ALLOW_ONELEVEL))
  73                 die("invalid ref format: %s", ref.buf);
  74
  75         return strbuf_detach(&ref, NULL);
  76 }
  77
  78 /*
  79  * The value being parsed is <oldvalue> (as opposed to <newvalue>; the
  80  * difference affects which error messages are generated):
  81  */
  82 #define PARSE_SHA1_OLD 0x01
  83
  84 /*
  85  * For backwards compatibility, accept an empty string for update's
  86  * <newvalue> in binary mode to be equivalent to specifying zeros.
  87  */
  88 #define PARSE_SHA1_ALLOW_EMPTY 0x02
  89
  90 /*
  91  * Parse an argument separator followed by the next argument, if any.
  92  * If there is an argument, convert it to a SHA-1, write it to sha1,
  93  * set *next to point at the character terminating the argument, and
  94  * return 0.  If there is no argument at all (not even the empty
  95  * string), return 1 and leave *next unchanged.  If the value is
  96  * provided but cannot be converted to a SHA-1, die.  flags can
  97  * include PARSE_SHA1_OLD and/or PARSE_SHA1_ALLOW_EMPTY.
  98  */
  99 static int parse_next_oid(const char **next, const char *end,
 100                           struct object_id *oid,
 101                           const char *command, const char *refname,
 102                           int flags)
 103 {
 104         struct strbuf arg = STRBUF_INIT;
 105         int ret = 0;
 106
 107         if (*next == end)
 108                 goto eof;
 109
 110         if (line_termination) {
 111                 /* Without -z, consume SP and use next argument */
 112                 if (!**next || **next == line_termination)
 113                         return 1;
 114                 if (**next != ' ')
 115                         die("%s %s: expected SP but got: %s",
 116                             command, refname, *next);
 117                 (*next)++;
 118                 *next = parse_arg(*next, &arg);
 119                 if (arg.len) {
 120                         if (get_oid(arg.buf, oid))
 121                                 goto invalid;
 122                 } else {
 123                         /* Without -z, an empty value means all zeros: */
 124                         oidclr(oid);
 125                 }
 126         } else {
 127                 /* With -z, read the next NUL-terminated line */
 128                 if (**next)
 129                         die("%s %s: expected NUL but got: %s",
 130                             command, refname, *next);
 131                 (*next)++;
 132                 if (*next == end)
 133                         goto eof;
 134                 strbuf_addstr(&arg, *next);
 135                 *next += arg.len;
 136
 137                 if (arg.len) {
 138                         if (get_oid(arg.buf, oid))
 139                                 goto invalid;
 140                 } else if (flags & PARSE_SHA1_ALLOW_EMPTY) {
 141                         /* With -z, treat an empty value as all zeros: */
 142                         warning("%s %s: missing <newvalue>, treating as zero",
 143                                 command, refname);
 144                         oidclr(oid);
 145                 } else {
 146                         /*
 147                          * With -z, an empty non-required value means
 148                          * unspecified:
 149                          */
 150                         ret = 1;
 151                 }
 152         }
 153
 154         strbuf_release(&arg);
 155
 156         return ret;
 157
 158  invalid:
 159         die(flags & PARSE_SHA1_OLD ?
 160             "%s %s: invalid <oldvalue>: %s" :
 161             "%s %s: invalid <newvalue>: %s",
 162             command, refname, arg.buf);
 163
 164  eof:
 165         die(flags & PARSE_SHA1_OLD ?
 166             "%s %s: unexpected end of input when reading <oldvalue>" :
 167             "%s %s: unexpected end of input when reading <newvalue>",
 168             command, refname);
 169 }
 170
 171
 172 /*
 173  * The following five parse_cmd_*() functions parse the corresponding
 174  * command.  In each case, next points at the character following the
 175  * command name and the following space.  They each return a pointer
 176  * to the character terminating the command, and die with an
 177  * explanatory message if there are any parsing problems.  All of
 178  * these functions handle either text or binary format input,
 179  * depending on how line_termination is set.
 180  */
 181
 182 static void parse_cmd_update(struct ref_transaction *transaction,
 183                              const char *next, const char *end)
 184 {
 185         struct strbuf err = STRBUF_INIT;
 186         char *refname;
 187         struct object_id new_oid, old_oid;
 188         int have_old;
 189
 190         refname = parse_refname(&next);
 191         if (!refname)
 192                 die("update: missing <ref>");
 193
 194         if (parse_next_oid(&next, end, &new_oid, "update", refname,
 195                            PARSE_SHA1_ALLOW_EMPTY))
 196                 die("update %s: missing <newvalue>", refname);
 197
 198         have_old = !parse_next_oid(&next, end, &old_oid, "update", refname,
 199                                    PARSE_SHA1_OLD);
 200
 201         if (*next != line_termination)
 202                 die("update %s: extra input: %s", refname, next);
 203
 204         if (ref_transaction_update(transaction, refname,
 205                                    &new_oid, have_old ? &old_oid : NULL,
 206                                    update_flags | create_reflog_flag,
 207                                    msg, &err))
 208                 die("%s", err.buf);
 209
 210         update_flags = default_flags;
 211         free(refname);
 212         strbuf_release(&err);
 213 }
 214
 215 static void parse_cmd_create(struct ref_transaction *transaction,
 216                              const char *next, const char *end)
 217 {
 218         struct strbuf err = STRBUF_INIT;
 219         char *refname;
 220         struct object_id new_oid;
 221
 222         refname = parse_refname(&next);
 223         if (!refname)
 224                 die("create: missing <ref>");
 225
 226         if (parse_next_oid(&next, end, &new_oid, "create", refname, 0))
 227                 die("create %s: missing <newvalue>", refname);
 228
 229         if (is_null_oid(&new_oid))
 230                 die("create %s: zero <newvalue>", refname);
 231
 232         if (*next != line_termination)
 233                 die("create %s: extra input: %s", refname, next);
 234
 235         if (ref_transaction_create(transaction, refname, &new_oid,
 236                                    update_flags | create_reflog_flag,
 237                                    msg, &err))
 238                 die("%s", err.buf);
 239
 240         update_flags = default_flags;
 241         free(refname);
 242         strbuf_release(&err);
 243 }
 244
 245 static void parse_cmd_delete(struct ref_transaction *transaction,
 246                              const char *next, const char *end)
 247 {
 248         struct strbuf err = STRBUF_INIT;
 249         char *refname;
 250         struct object_id old_oid;
 251         int have_old;
 252
 253         refname = parse_refname(&next);
 254         if (!refname)
 255                 die("delete: missing <ref>");
 256
 257         if (parse_next_oid(&next, end, &old_oid, "delete", refname,
 258                            PARSE_SHA1_OLD)) {
 259                 have_old = 0;
 260         } else {
 261                 if (is_null_oid(&old_oid))
 262                         die("delete %s: zero <oldvalue>", refname);
 263                 have_old = 1;
 264         }
 265
 266         if (*next != line_termination)
 267                 die("delete %s: extra input: %s", refname, next);
 268
 269         if (ref_transaction_delete(transaction, refname,
 270                                    have_old ? &old_oid : NULL,
 271                                    update_flags, msg, &err))
 272                 die("%s", err.buf);
 273
 274         update_flags = default_flags;
 275         free(refname);
 276         strbuf_release(&err);
 277 }
 278
 279 static void parse_cmd_verify(struct ref_transaction *transaction,
 280                              const char *next, const char *end)
 281 {
 282         struct strbuf err = STRBUF_INIT;
 283         char *refname;
 284         struct object_id old_oid;
 285
 286         refname = parse_refname(&next);
 287         if (!refname)
 288                 die("verify: missing <ref>");
 289
 290         if (parse_next_oid(&next, end, &old_oid, "verify", refname,
 291                            PARSE_SHA1_OLD))
 292                 oidclr(&old_oid);
 293
 294         if (*next != line_termination)
 295                 die("verify %s: extra input: %s", refname, next);
 296
 297         if (ref_transaction_verify(transaction, refname, &old_oid,
 298                                    update_flags, &err))
 299                 die("%s", err.buf);
 300
 301         update_flags = default_flags;
 302         free(refname);
 303         strbuf_release(&err);
 304 }
 305
 306 static void report_ok(const char *command)
 307 {
 308         fprintf(stdout, "%s: ok\n", command);
 309         fflush(stdout);
 310 }
 311
 312 static void parse_cmd_option(struct ref_transaction *transaction,
 313                              const char *next, const char *end)
 314 {
 315         const char *rest;
 316         if (skip_prefix(next, "no-deref", &rest) && *rest == line_termination)
 317                 update_flags |= REF_NO_DEREF;
 318         else
 319                 die("option unknown: %s", next);
 320 }
 321
 322 static void parse_cmd_start(struct ref_transaction *transaction,
 323                             const char *next, const char *end)
 324 {
 325         if (*next != line_termination)
 326                 die("start: extra input: %s", next);
 327         report_ok("start");
 328 }
 329
 330 static void parse_cmd_prepare(struct ref_transaction *transaction,
 331                               const char *next, const char *end)
 332 {
 333         struct strbuf error = STRBUF_INIT;
 334         if (*next != line_termination)
 335                 die("prepare: extra input: %s", next);
 336         if (ref_transaction_prepare(transaction, &error))
 337                 die("prepare: %s", error.buf);
 338         report_ok("prepare");
 339 }
 340
 341 static void parse_cmd_abort(struct ref_transaction *transaction,
 342                             const char *next, const char *end)
 343 {
 344         struct strbuf error = STRBUF_INIT;
 345         if (*next != line_termination)
 346                 die("abort: extra input: %s", next);
 347         if (ref_transaction_abort(transaction, &error))
 348                 die("abort: %s", error.buf);
 349         report_ok("abort");
 350 }
 351
 352 static void parse_cmd_commit(struct ref_transaction *transaction,
 353                              const char *next, const char *end)
 354 {
 355         struct strbuf error = STRBUF_INIT;
 356         if (*next != line_termination)
 357                 die("commit: extra input: %s", next);
 358         if (ref_transaction_commit(transaction, &error))
 359                 die("commit: %s", error.buf);
 360         report_ok("commit");
 361         ref_transaction_free(transaction);
 362 }
 363
 364 enum update_refs_state {
 365         /* Non-transactional state open for updates. */
 366         UPDATE_REFS_OPEN,
 367         /* A transaction has been started. */
 368         UPDATE_REFS_STARTED,
 369         /* References are locked and ready for commit */
 370         UPDATE_REFS_PREPARED,
 371         /* Transaction has been committed or closed. */
 372         UPDATE_REFS_CLOSED,
 373 };
 374
 375 static const struct parse_cmd {
 376         const char *prefix;
 377         void (*fn)(struct ref_transaction *, const char *, const char *);
 378         unsigned args;
 379         enum update_refs_state state;
 380 } command[] = {
 381         { "update",  parse_cmd_update,  3, UPDATE_REFS_OPEN },
 382         { "create",  parse_cmd_create,  2, UPDATE_REFS_OPEN },
 383         { "delete",  parse_cmd_delete,  2, UPDATE_REFS_OPEN },
 384         { "verify",  parse_cmd_verify,  2, UPDATE_REFS_OPEN },
 385         { "option",  parse_cmd_option,  1, UPDATE_REFS_OPEN },
 386         { "start",   parse_cmd_start,   0, UPDATE_REFS_STARTED },
 387         { "prepare", parse_cmd_prepare, 0, UPDATE_REFS_PREPARED },
 388         { "abort",   parse_cmd_abort,   0, UPDATE_REFS_CLOSED },
 389         { "commit",  parse_cmd_commit,  0, UPDATE_REFS_CLOSED },
 390 };
 391
 392 static void update_refs_stdin(void)
 393 {
 394         struct strbuf input = STRBUF_INIT, err = STRBUF_INIT;
 395         enum update_refs_state state = UPDATE_REFS_OPEN;
 396         struct ref_transaction *transaction;
 397         int i, j;
 398
 399         transaction = ref_transaction_begin(&err);
 400         if (!transaction)
 401                 die("%s", err.buf);
 402
 403         /* Read each line dispatch its command */
 404         while (!strbuf_getwholeline(&input, stdin, line_termination)) {
 405                 const struct parse_cmd *cmd = NULL;
 406
 407                 if (*input.buf == line_termination)
 408                         die("empty command in input");
 409                 else if (isspace(*input.buf))
 410                         die("whitespace before command: %s", input.buf);
 411
 412                 for (i = 0; i < ARRAY_SIZE(command); i++) {
 413                         const char *prefix = command[i].prefix;
 414                         char c;
 415
 416                         if (!starts_with(input.buf, prefix))
 417                                 continue;
 418
 419                         /*
 420                          * If the command has arguments, verify that it's
 421                          * followed by a space. Otherwise, it shall be followed
 422                          * by a line terminator.
 423                          */
 424                         c = command[i].args ? ' ' : line_termination;
 425                         if (input.buf[strlen(prefix)] != c)
 426                                 continue;
 427
 428                         cmd = &command[i];
 429                         break;
 430                 }
 431                 if (!cmd)
 432                         die("unknown command: %s", input.buf);
 433
 434                 /*
 435                  * Read additional arguments if NUL-terminated. Do not raise an
 436                  * error in case there is an early EOF to let the command
 437                  * handle missing arguments with a proper error message.
 438                  */
 439                 for (j = 1; line_termination == '\0' && j < cmd->args; j++)
 440                         if (strbuf_appendwholeline(&input, stdin, line_termination))
 441                                 break;
 442
 443                 switch (state) {
 444                 case UPDATE_REFS_OPEN:
 445                 case UPDATE_REFS_STARTED:
 446                         if (state == UPDATE_REFS_STARTED && cmd->state == UPDATE_REFS_STARTED)
 447                                 die("cannot restart ongoing transaction");
 448                         /* Do not downgrade a transaction to a non-transaction. */
 449                         if (cmd->state >= state)
 450                                 state = cmd->state;
 451                         break;
 452                 case UPDATE_REFS_PREPARED:
 453                         if (cmd->state != UPDATE_REFS_CLOSED)
 454                                 die("prepared transactions can only be closed");
 455                         state = cmd->state;
 456                         break;
 457                 case UPDATE_REFS_CLOSED:
 458                         if (cmd->state != UPDATE_REFS_STARTED)
 459                                 die("transaction is closed");
 460
 461                         /*
 462                          * Open a new transaction if we're currently closed and
 463                          * get a "start".
 464                          */
 465                         state = cmd->state;
 466                         transaction = ref_transaction_begin(&err);
 467                         if (!transaction)
 468                                 die("%s", err.buf);
 469
 470                         break;
 471                 }
 472
 473                 cmd->fn(transaction, input.buf + strlen(cmd->prefix) + !!cmd->args,
 474                         input.buf + input.len);
 475         }
 476
 477         switch (state) {
 478         case UPDATE_REFS_OPEN:
 479                 /* Commit by default if no transaction was requested. */
 480                 if (ref_transaction_commit(transaction, &err))
 481                         die("%s", err.buf);
 482                 ref_transaction_free(transaction);
 483                 break;
 484         case UPDATE_REFS_STARTED:
 485         case UPDATE_REFS_PREPARED:
 486                 /* If using a transaction, we want to abort it. */
 487                 if (ref_transaction_abort(transaction, &err))
 488                         die("%s", err.buf);
 489                 break;
 490         case UPDATE_REFS_CLOSED:
 491                 /* Otherwise no need to do anything, the transaction was closed already. */
 492                 break;
 493         }
 494
 495         strbuf_release(&err);
 496         strbuf_release(&input);
 497 }
 498
 499 int cmd_update_ref(int argc, const char **argv, const char *prefix)
 500 {
 501         const char *refname, *oldval;
 502         struct object_id oid, oldoid;
 503         int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0;
 504         int create_reflog = 0;
 505         struct option options[] = {
 506                 OPT_STRING( 'm', NULL, &msg, N_("reason"), N_("reason of the update")),
 507                 OPT_BOOL('d', NULL, &delete, N_("delete the reference")),
 508                 OPT_BOOL( 0 , "no-deref", &no_deref,
 509                                         N_("update <refname> not the one it points to")),
 510                 OPT_BOOL('z', NULL, &end_null, N_("stdin has NUL-terminated arguments")),
 511                 OPT_BOOL( 0 , "stdin", &read_stdin, N_("read updates from stdin")),
 512                 OPT_BOOL( 0 , "create-reflog", &create_reflog, N_("create a reflog")),
 513                 OPT_END(),
 514         };
 515
 516         git_config(git_default_config, NULL);
 517         argc = parse_options(argc, argv, prefix, options, git_update_ref_usage,
 518                              0);
 519         if (msg && !*msg)
 520                 die("Refusing to perform update with empty message.");
 521
 522         create_reflog_flag = create_reflog ? REF_FORCE_CREATE_REFLOG : 0;
 523
 524         if (no_deref) {
 525                 default_flags = REF_NO_DEREF;
 526                 update_flags = default_flags;
 527         }
 528
 529         if (read_stdin) {
 530                 if (delete || argc > 0)
 531                         usage_with_options(git_update_ref_usage, options);
 532                 if (end_null)
 533                         line_termination = '\0';
 534                 update_refs_stdin();
 535                 return 0;
 536         }
 537
 538         if (end_null)
 539                 usage_with_options(git_update_ref_usage, options);
 540
 541         if (delete) {
 542                 if (argc < 1 || argc > 2)
 543                         usage_with_options(git_update_ref_usage, options);
 544                 refname = argv[0];
 545                 oldval = argv[1];
 546         } else {
 547                 const char *value;
 548                 if (argc < 2 || argc > 3)
 549                         usage_with_options(git_update_ref_usage, options);
 550                 refname = argv[0];
 551                 value = argv[1];
 552                 oldval = argv[2];
 553                 if (get_oid(value, &oid))
 554                         die("%s: not a valid SHA1", value);
 555         }
 556
 557         if (oldval) {
 558                 if (!*oldval)
 559                         /*
 560                          * The empty string implies that the reference
 561                          * must not already exist:
 562                          */
 563                         oidclr(&oldoid);
 564                 else if (get_oid(oldval, &oldoid))
 565                         die("%s: not a valid old SHA1", oldval);
 566         }
 567
 568         if (delete)
 569                 /*
 570                  * For purposes of backwards compatibility, we treat
 571                  * NULL_SHA1 as "don't care" here:
 572                  */
 573                 return delete_ref(msg, refname,
 574                                   (oldval && !is_null_oid(&oldoid)) ? &oldoid : NULL,
 575                                   default_flags);
 576         else
 577                 return update_ref(msg, refname, &oid, oldval ? &oldoid : NULL,
 578                                   default_flags | create_reflog_flag,
 579                                   UPDATE_REFS_DIE_ON_ERR);
 580 }