builtin/update-ref.c

   1 #include "cache.h"
   2 #include "config.h"
   3 #include "refs.h"
   4 #include "builtin.h"
   5 #include "parse-options.h"
   6 #include "quote.h"
   7 #include "argv-array.h"
   8
   9 static const char * const git_update_ref_usage[] = {
  10         N_("git update-ref [<options>] -d <refname> [<old-val>]"),
  11         N_("git update-ref [<options>]    <refname> <new-val> [<old-val>]"),
  12         N_("git update-ref [<options>] --stdin [-z]"),
  13         NULL
  14 };
  15
  16 static char line_termination = '\n';
  17 static unsigned int update_flags;
  18 static unsigned int default_flags;
  19 static unsigned create_reflog_flag;
  20 static const char *msg;
  21
  22 /*
  23  * Parse one whitespace- or NUL-terminated, possibly C-quoted argument
  24  * and append the result to arg.  Return a pointer to the terminator.
  25  * Die if there is an error in how the argument is C-quoted.  This
  26  * function is only used if not -z.
  27  */
  28 static const char *parse_arg(const char *next, struct strbuf *arg)
  29 {
  30         if (*next == '"') {
  31                 const char *orig = next;
  32
  33                 if (unquote_c_style(arg, next, &next))
  34                         die("badly quoted argument: %s", orig);
  35                 if (*next && !isspace(*next))
  36                         die("unexpected character after quoted argument: %s", orig);
  37         } else {
  38                 while (*next && !isspace(*next))
  39                         strbuf_addch(arg, *next++);
  40         }
  41
  42         return next;
  43 }
  44
  45 /*
  46  * Parse the reference name immediately after "command SP".  If not
  47  * -z, then handle C-quoting.  Return a pointer to a newly allocated
  48  * string containing the name of the reference, or NULL if there was
  49  * an error.  Update *next to point at the character that terminates
  50  * the argument.  Die if C-quoting is malformed or the reference name
  51  * is invalid.
  52  */
  53 static char *parse_refname(struct strbuf *input, const char **next)
  54 {
  55         struct strbuf ref = STRBUF_INIT;
  56
  57         if (line_termination) {
  58                 /* Without -z, use the next argument */
  59                 *next = parse_arg(*next, &ref);
  60         } else {
  61                 /* With -z, use everything up to the next NUL */
  62                 strbuf_addstr(&ref, *next);
  63                 *next += ref.len;
  64         }
  65
  66         if (!ref.len) {
  67                 strbuf_release(&ref);
  68                 return NULL;
  69         }
  70
  71         if (check_refname_format(ref.buf, REFNAME_ALLOW_ONELEVEL))
  72                 die("invalid ref format: %s", ref.buf);
  73
  74         return strbuf_detach(&ref, NULL);
  75 }
  76
  77 /*
  78  * The value being parsed is <oldvalue> (as opposed to <newvalue>; the
  79  * difference affects which error messages are generated):
  80  */
  81 #define PARSE_SHA1_OLD 0x01
  82
  83 /*
  84  * For backwards compatibility, accept an empty string for update's
  85  * <newvalue> in binary mode to be equivalent to specifying zeros.
  86  */
  87 #define PARSE_SHA1_ALLOW_EMPTY 0x02
  88
  89 /*
  90  * Parse an argument separator followed by the next argument, if any.
  91  * If there is an argument, convert it to a SHA-1, write it to sha1,
  92  * set *next to point at the character terminating the argument, and
  93  * return 0.  If there is no argument at all (not even the empty
  94  * string), return 1 and leave *next unchanged.  If the value is
  95  * provided but cannot be converted to a SHA-1, die.  flags can
  96  * include PARSE_SHA1_OLD and/or PARSE_SHA1_ALLOW_EMPTY.
  97  */
  98 static int parse_next_oid(struct strbuf *input, const char **next,
  99                           struct object_id *oid,
 100                           const char *command, const char *refname,
 101                           int flags)
 102 {
 103         struct strbuf arg = STRBUF_INIT;
 104         int ret = 0;
 105
 106         if (*next == input->buf + input->len)
 107                 goto eof;
 108
 109         if (line_termination) {
 110                 /* Without -z, consume SP and use next argument */
 111                 if (!**next || **next == line_termination)
 112                         return 1;
 113                 if (**next != ' ')
 114                         die("%s %s: expected SP but got: %s",
 115                             command, refname, *next);
 116                 (*next)++;
 117                 *next = parse_arg(*next, &arg);
 118                 if (arg.len) {
 119                         if (get_oid(arg.buf, oid))
 120                                 goto invalid;
 121                 } else {
 122                         /* Without -z, an empty value means all zeros: */
 123                         oidclr(oid);
 124                 }
 125         } else {
 126                 /* With -z, read the next NUL-terminated line */
 127                 if (**next)
 128                         die("%s %s: expected NUL but got: %s",
 129                             command, refname, *next);
 130                 (*next)++;
 131                 if (*next == input->buf + input->len)
 132                         goto eof;
 133                 strbuf_addstr(&arg, *next);
 134                 *next += arg.len;
 135
 136                 if (arg.len) {
 137                         if (get_oid(arg.buf, oid))
 138                                 goto invalid;
 139                 } else if (flags & PARSE_SHA1_ALLOW_EMPTY) {
 140                         /* With -z, treat an empty value as all zeros: */
 141                         warning("%s %s: missing <newvalue>, treating as zero",
 142                                 command, refname);
 143                         oidclr(oid);
 144                 } else {
 145                         /*
 146                          * With -z, an empty non-required value means
 147                          * unspecified:
 148                          */
 149                         ret = 1;
 150                 }
 151         }
 152
 153         strbuf_release(&arg);
 154
 155         return ret;
 156
 157  invalid:
 158         die(flags & PARSE_SHA1_OLD ?
 159             "%s %s: invalid <oldvalue>: %s" :
 160             "%s %s: invalid <newvalue>: %s",
 161             command, refname, arg.buf);
 162
 163  eof:
 164         die(flags & PARSE_SHA1_OLD ?
 165             "%s %s: unexpected end of input when reading <oldvalue>" :
 166             "%s %s: unexpected end of input when reading <newvalue>",
 167             command, refname);
 168 }
 169
 170
 171 /*
 172  * The following five parse_cmd_*() functions parse the corresponding
 173  * command.  In each case, next points at the character following the
 174  * command name and the following space.  They each return a pointer
 175  * to the character terminating the command, and die with an
 176  * explanatory message if there are any parsing problems.  All of
 177  * these functions handle either text or binary format input,
 178  * depending on how line_termination is set.
 179  */
 180
 181 static const char *parse_cmd_update(struct ref_transaction *transaction,
 182                                     struct strbuf *input, const char *next)
 183 {
 184         struct strbuf err = STRBUF_INIT;
 185         char *refname;
 186         struct object_id new_oid, old_oid;
 187         int have_old;
 188
 189         refname = parse_refname(input, &next);
 190         if (!refname)
 191                 die("update: missing <ref>");
 192
 193         if (parse_next_oid(input, &next, &new_oid, "update", refname,
 194                            PARSE_SHA1_ALLOW_EMPTY))
 195                 die("update %s: missing <newvalue>", refname);
 196
 197         have_old = !parse_next_oid(input, &next, &old_oid, "update", refname,
 198                                    PARSE_SHA1_OLD);
 199
 200         if (*next != line_termination)
 201                 die("update %s: extra input: %s", refname, next);
 202
 203         if (ref_transaction_update(transaction, refname,
 204                                    &new_oid, have_old ? &old_oid : NULL,
 205                                    update_flags | create_reflog_flag,
 206                                    msg, &err))
 207                 die("%s", err.buf);
 208
 209         update_flags = default_flags;
 210         free(refname);
 211         strbuf_release(&err);
 212
 213         return next;
 214 }
 215
 216 static const char *parse_cmd_create(struct ref_transaction *transaction,
 217                                     struct strbuf *input, const char *next)
 218 {
 219         struct strbuf err = STRBUF_INIT;
 220         char *refname;
 221         struct object_id new_oid;
 222
 223         refname = parse_refname(input, &next);
 224         if (!refname)
 225                 die("create: missing <ref>");
 226
 227         if (parse_next_oid(input, &next, &new_oid, "create", refname, 0))
 228                 die("create %s: missing <newvalue>", refname);
 229
 230         if (is_null_oid(&new_oid))
 231                 die("create %s: zero <newvalue>", refname);
 232
 233         if (*next != line_termination)
 234                 die("create %s: extra input: %s", refname, next);
 235
 236         if (ref_transaction_create(transaction, refname, &new_oid,
 237                                    update_flags | create_reflog_flag,
 238                                    msg, &err))
 239                 die("%s", err.buf);
 240
 241         update_flags = default_flags;
 242         free(refname);
 243         strbuf_release(&err);
 244
 245         return next;
 246 }
 247
 248 static const char *parse_cmd_delete(struct ref_transaction *transaction,
 249                                     struct strbuf *input, const char *next)
 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(input, &next);
 257         if (!refname)
 258                 die("delete: missing <ref>");
 259
 260         if (parse_next_oid(input, &next, &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         return next;
 282 }
 283
 284 static const char *parse_cmd_verify(struct ref_transaction *transaction,
 285                                     struct strbuf *input, const char *next)
 286 {
 287         struct strbuf err = STRBUF_INIT;
 288         char *refname;
 289         struct object_id old_oid;
 290
 291         refname = parse_refname(input, &next);
 292         if (!refname)
 293                 die("verify: missing <ref>");
 294
 295         if (parse_next_oid(input, &next, &old_oid, "verify", refname,
 296                            PARSE_SHA1_OLD))
 297                 oidclr(&old_oid);
 298
 299         if (*next != line_termination)
 300                 die("verify %s: extra input: %s", refname, next);
 301
 302         if (ref_transaction_verify(transaction, refname, &old_oid,
 303                                    update_flags, &err))
 304                 die("%s", err.buf);
 305
 306         update_flags = default_flags;
 307         free(refname);
 308         strbuf_release(&err);
 309
 310         return next;
 311 }
 312
 313 static const char *parse_cmd_option(struct strbuf *input, const char *next)
 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         return rest;
 321 }
 322
 323 static void update_refs_stdin(struct ref_transaction *transaction)
 324 {
 325         struct strbuf input = STRBUF_INIT;
 326         const char *next;
 327
 328         if (strbuf_read(&input, 0, 1000) < 0)
 329                 die_errno("could not read from stdin");
 330         next = input.buf;
 331         /* Read each line dispatch its command */
 332         while (next < input.buf + input.len) {
 333                 if (*next == line_termination)
 334                         die("empty command in input");
 335                 else if (isspace(*next))
 336                         die("whitespace before command: %s", next);
 337                 else if (skip_prefix(next, "update ", &next))
 338                         next = parse_cmd_update(transaction, &input, next);
 339                 else if (skip_prefix(next, "create ", &next))
 340                         next = parse_cmd_create(transaction, &input, next);
 341                 else if (skip_prefix(next, "delete ", &next))
 342                         next = parse_cmd_delete(transaction, &input, next);
 343                 else if (skip_prefix(next, "verify ", &next))
 344                         next = parse_cmd_verify(transaction, &input, next);
 345                 else if (skip_prefix(next, "option ", &next))
 346                         next = parse_cmd_option(&input, next);
 347                 else
 348                         die("unknown command: %s", next);
 349
 350                 next++;
 351         }
 352
 353         strbuf_release(&input);
 354 }
 355
 356 int cmd_update_ref(int argc, const char **argv, const char *prefix)
 357 {
 358         const char *refname, *oldval;
 359         struct object_id oid, oldoid;
 360         int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0;
 361         int create_reflog = 0;
 362         struct option options[] = {
 363                 OPT_STRING( 'm', NULL, &msg, N_("reason"), N_("reason of the update")),
 364                 OPT_BOOL('d', NULL, &delete, N_("delete the reference")),
 365                 OPT_BOOL( 0 , "no-deref", &no_deref,
 366                                         N_("update <refname> not the one it points to")),
 367                 OPT_BOOL('z', NULL, &end_null, N_("stdin has NUL-terminated arguments")),
 368                 OPT_BOOL( 0 , "stdin", &read_stdin, N_("read updates from stdin")),
 369                 OPT_BOOL( 0 , "create-reflog", &create_reflog, N_("create a reflog")),
 370                 OPT_END(),
 371         };
 372
 373         git_config(git_default_config, NULL);
 374         argc = parse_options(argc, argv, prefix, options, git_update_ref_usage,
 375                              0);
 376         if (msg && !*msg)
 377                 die("Refusing to perform update with empty message.");
 378
 379         create_reflog_flag = create_reflog ? REF_FORCE_CREATE_REFLOG : 0;
 380
 381         if (no_deref) {
 382                 default_flags = REF_NO_DEREF;
 383                 update_flags = default_flags;
 384         }
 385
 386         if (read_stdin) {
 387                 struct strbuf err = STRBUF_INIT;
 388                 struct ref_transaction *transaction;
 389
 390                 transaction = ref_transaction_begin(&err);
 391                 if (!transaction)
 392                         die("%s", err.buf);
 393                 if (delete || argc > 0)
 394                         usage_with_options(git_update_ref_usage, options);
 395                 if (end_null)
 396                         line_termination = '\0';
 397                 update_refs_stdin(transaction);
 398                 if (ref_transaction_commit(transaction, &err))
 399                         die("%s", err.buf);
 400                 ref_transaction_free(transaction);
 401                 strbuf_release(&err);
 402                 return 0;
 403         }
 404
 405         if (end_null)
 406                 usage_with_options(git_update_ref_usage, options);
 407
 408         if (delete) {
 409                 if (argc < 1 || argc > 2)
 410                         usage_with_options(git_update_ref_usage, options);
 411                 refname = argv[0];
 412                 oldval = argv[1];
 413         } else {
 414                 const char *value;
 415                 if (argc < 2 || argc > 3)
 416                         usage_with_options(git_update_ref_usage, options);
 417                 refname = argv[0];
 418                 value = argv[1];
 419                 oldval = argv[2];
 420                 if (get_oid(value, &oid))
 421                         die("%s: not a valid SHA1", value);
 422         }
 423
 424         if (oldval) {
 425                 if (!*oldval)
 426                         /*
 427                          * The empty string implies that the reference
 428                          * must not already exist:
 429                          */
 430                         oidclr(&oldoid);
 431                 else if (get_oid(oldval, &oldoid))
 432                         die("%s: not a valid old SHA1", oldval);
 433         }
 434
 435         if (delete)
 436                 /*
 437                  * For purposes of backwards compatibility, we treat
 438                  * NULL_SHA1 as "don't care" here:
 439                  */
 440                 return delete_ref(msg, refname,
 441                                   (oldval && !is_null_oid(&oldoid)) ? &oldoid : NULL,
 442                                   default_flags);
 443         else
 444                 return update_ref(msg, refname, &oid, oldval ? &oldoid : NULL,
 445                                   default_flags | create_reflog_flag,
 446                                   UPDATE_REFS_DIE_ON_ERR);
 447 }