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 int update_flags;
  18 static unsigned create_reflog_flag;
  19 static const char *msg;
  20
  21 /*
  22  * Parse one whitespace- or NUL-terminated, possibly C-quoted argument
  23  * and append the result to arg.  Return a pointer to the terminator.
  24  * Die if there is an error in how the argument is C-quoted.  This
  25  * function is only used if not -z.
  26  */
  27 static const char *parse_arg(const char *next, struct strbuf *arg)
  28 {
  29         if (*next == '"') {
  30                 const char *orig = next;
  31
  32                 if (unquote_c_style(arg, next, &next))
  33                         die("badly quoted argument: %s", orig);
  34                 if (*next && !isspace(*next))
  35                         die("unexpected character after quoted argument: %s", orig);
  36         } else {
  37                 while (*next && !isspace(*next))
  38                         strbuf_addch(arg, *next++);
  39         }
  40
  41         return next;
  42 }
  43
  44 /*
  45  * Parse the reference name immediately after "command SP".  If not
  46  * -z, then handle C-quoting.  Return a pointer to a newly allocated
  47  * string containing the name of the reference, or NULL if there was
  48  * an error.  Update *next to point at the character that terminates
  49  * the argument.  Die if C-quoting is malformed or the reference name
  50  * is invalid.
  51  */
  52 static char *parse_refname(struct strbuf *input, const char **next)
  53 {
  54         struct strbuf ref = STRBUF_INIT;
  55
  56         if (line_termination) {
  57                 /* Without -z, use the next argument */
  58                 *next = parse_arg(*next, &ref);
  59         } else {
  60                 /* With -z, use everything up to the next NUL */
  61                 strbuf_addstr(&ref, *next);
  62                 *next += ref.len;
  63         }
  64
  65         if (!ref.len) {
  66                 strbuf_release(&ref);
  67                 return NULL;
  68         }
  69
  70         if (check_refname_format(ref.buf, REFNAME_ALLOW_ONELEVEL))
  71                 die("invalid ref format: %s", ref.buf);
  72
  73         return strbuf_detach(&ref, NULL);
  74 }
  75
  76 /*
  77  * The value being parsed is <oldvalue> (as opposed to <newvalue>; the
  78  * difference affects which error messages are generated):
  79  */
  80 #define PARSE_SHA1_OLD 0x01
  81
  82 /*
  83  * For backwards compatibility, accept an empty string for update's
  84  * <newvalue> in binary mode to be equivalent to specifying zeros.
  85  */
  86 #define PARSE_SHA1_ALLOW_EMPTY 0x02
  87
  88 /*
  89  * Parse an argument separator followed by the next argument, if any.
  90  * If there is an argument, convert it to a SHA-1, write it to sha1,
  91  * set *next to point at the character terminating the argument, and
  92  * return 0.  If there is no argument at all (not even the empty
  93  * string), return 1 and leave *next unchanged.  If the value is
  94  * provided but cannot be converted to a SHA-1, die.  flags can
  95  * include PARSE_SHA1_OLD and/or PARSE_SHA1_ALLOW_EMPTY.
  96  */
  97 static int parse_next_oid(struct strbuf *input, const char **next,
  98                           struct object_id *oid,
  99                           const char *command, const char *refname,
 100                           int flags)
 101 {
 102         struct strbuf arg = STRBUF_INIT;
 103         int ret = 0;
 104
 105         if (*next == input->buf + input->len)
 106                 goto eof;
 107
 108         if (line_termination) {
 109                 /* Without -z, consume SP and use next argument */
 110                 if (!**next || **next == line_termination)
 111                         return 1;
 112                 if (**next != ' ')
 113                         die("%s %s: expected SP but got: %s",
 114                             command, refname, *next);
 115                 (*next)++;
 116                 *next = parse_arg(*next, &arg);
 117                 if (arg.len) {
 118                         if (get_oid(arg.buf, oid))
 119                                 goto invalid;
 120                 } else {
 121                         /* Without -z, an empty value means all zeros: */
 122                         oidclr(oid);
 123                 }
 124         } else {
 125                 /* With -z, read the next NUL-terminated line */
 126                 if (**next)
 127                         die("%s %s: expected NUL but got: %s",
 128                             command, refname, *next);
 129                 (*next)++;
 130                 if (*next == input->buf + input->len)
 131                         goto eof;
 132                 strbuf_addstr(&arg, *next);
 133                 *next += arg.len;
 134
 135                 if (arg.len) {
 136                         if (get_oid(arg.buf, oid))
 137                                 goto invalid;
 138                 } else if (flags & PARSE_SHA1_ALLOW_EMPTY) {
 139                         /* With -z, treat an empty value as all zeros: */
 140                         warning("%s %s: missing <newvalue>, treating as zero",
 141                                 command, refname);
 142                         oidclr(oid);
 143                 } else {
 144                         /*
 145                          * With -z, an empty non-required value means
 146                          * unspecified:
 147                          */
 148                         ret = 1;
 149                 }
 150         }
 151
 152         strbuf_release(&arg);
 153
 154         return ret;
 155
 156  invalid:
 157         die(flags & PARSE_SHA1_OLD ?
 158             "%s %s: invalid <oldvalue>: %s" :
 159             "%s %s: invalid <newvalue>: %s",
 160             command, refname, arg.buf);
 161
 162  eof:
 163         die(flags & PARSE_SHA1_OLD ?
 164             "%s %s: unexpected end of input when reading <oldvalue>" :
 165             "%s %s: unexpected end of input when reading <newvalue>",
 166             command, refname);
 167 }
 168
 169
 170 /*
 171  * The following five parse_cmd_*() functions parse the corresponding
 172  * command.  In each case, next points at the character following the
 173  * command name and the following space.  They each return a pointer
 174  * to the character terminating the command, and die with an
 175  * explanatory message if there are any parsing problems.  All of
 176  * these functions handle either text or binary format input,
 177  * depending on how line_termination is set.
 178  */
 179
 180 static const char *parse_cmd_update(struct ref_transaction *transaction,
 181                                     struct strbuf *input, const char *next)
 182 {
 183         struct strbuf err = STRBUF_INIT;
 184         char *refname;
 185         struct object_id new_oid, old_oid;
 186         int have_old;
 187
 188         refname = parse_refname(input, &next);
 189         if (!refname)
 190                 die("update: missing <ref>");
 191
 192         if (parse_next_oid(input, &next, &new_oid, "update", refname,
 193                            PARSE_SHA1_ALLOW_EMPTY))
 194                 die("update %s: missing <newvalue>", refname);
 195
 196         have_old = !parse_next_oid(input, &next, &old_oid, "update", refname,
 197                                    PARSE_SHA1_OLD);
 198
 199         if (*next != line_termination)
 200                 die("update %s: extra input: %s", refname, next);
 201
 202         if (ref_transaction_update(transaction, refname,
 203                                    &new_oid, have_old ? &old_oid : NULL,
 204                                    update_flags | create_reflog_flag,
 205                                    msg, &err))
 206                 die("%s", err.buf);
 207
 208         update_flags = 0;
 209         free(refname);
 210         strbuf_release(&err);
 211
 212         return next;
 213 }
 214
 215 static const char *parse_cmd_create(struct ref_transaction *transaction,
 216                                     struct strbuf *input, const char *next)
 217 {
 218         struct strbuf err = STRBUF_INIT;
 219         char *refname;
 220         struct object_id new_oid;
 221
 222         refname = parse_refname(input, &next);
 223         if (!refname)
 224                 die("create: missing <ref>");
 225
 226         if (parse_next_oid(input, &next, &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 = 0;
 241         free(refname);
 242         strbuf_release(&err);
 243
 244         return next;
 245 }
 246
 247 static const char *parse_cmd_delete(struct ref_transaction *transaction,
 248                                     struct strbuf *input, const char *next)
 249 {
 250         struct strbuf err = STRBUF_INIT;
 251         char *refname;
 252         struct object_id old_oid;
 253         int have_old;
 254
 255         refname = parse_refname(input, &next);
 256         if (!refname)
 257                 die("delete: missing <ref>");
 258
 259         if (parse_next_oid(input, &next, &old_oid, "delete", refname,
 260                            PARSE_SHA1_OLD)) {
 261                 have_old = 0;
 262         } else {
 263                 if (is_null_oid(&old_oid))
 264                         die("delete %s: zero <oldvalue>", refname);
 265                 have_old = 1;
 266         }
 267
 268         if (*next != line_termination)
 269                 die("delete %s: extra input: %s", refname, next);
 270
 271         if (ref_transaction_delete(transaction, refname,
 272                                    have_old ? &old_oid : NULL,
 273                                    update_flags, msg, &err))
 274                 die("%s", err.buf);
 275
 276         update_flags = 0;
 277         free(refname);
 278         strbuf_release(&err);
 279
 280         return next;
 281 }
 282
 283 static const char *parse_cmd_verify(struct ref_transaction *transaction,
 284                                     struct strbuf *input, const char *next)
 285 {
 286         struct strbuf err = STRBUF_INIT;
 287         char *refname;
 288         struct object_id old_oid;
 289
 290         refname = parse_refname(input, &next);
 291         if (!refname)
 292                 die("verify: missing <ref>");
 293
 294         if (parse_next_oid(input, &next, &old_oid, "verify", refname,
 295                            PARSE_SHA1_OLD))
 296                 oidclr(&old_oid);
 297
 298         if (*next != line_termination)
 299                 die("verify %s: extra input: %s", refname, next);
 300
 301         if (ref_transaction_verify(transaction, refname, &old_oid,
 302                                    update_flags, &err))
 303                 die("%s", err.buf);
 304
 305         update_flags = 0;
 306         free(refname);
 307         strbuf_release(&err);
 308
 309         return next;
 310 }
 311
 312 static const char *parse_cmd_option(struct strbuf *input, const char *next)
 313 {
 314         if (!strncmp(next, "no-deref", 8) && next[8] == line_termination)
 315                 update_flags |= REF_NO_DEREF;
 316         else
 317                 die("option unknown: %s", next);
 318         return next + 8;
 319 }
 320
 321 static void update_refs_stdin(struct ref_transaction *transaction)
 322 {
 323         struct strbuf input = STRBUF_INIT;
 324         const char *next;
 325
 326         if (strbuf_read(&input, 0, 1000) < 0)
 327                 die_errno("could not read from stdin");
 328         next = input.buf;
 329         /* Read each line dispatch its command */
 330         while (next < input.buf + input.len) {
 331                 if (*next == line_termination)
 332                         die("empty command in input");
 333                 else if (isspace(*next))
 334                         die("whitespace before command: %s", next);
 335                 else if (starts_with(next, "update "))
 336                         next = parse_cmd_update(transaction, &input, next + 7);
 337                 else if (starts_with(next, "create "))
 338                         next = parse_cmd_create(transaction, &input, next + 7);
 339                 else if (starts_with(next, "delete "))
 340                         next = parse_cmd_delete(transaction, &input, next + 7);
 341                 else if (starts_with(next, "verify "))
 342                         next = parse_cmd_verify(transaction, &input, next + 7);
 343                 else if (starts_with(next, "option "))
 344                         next = parse_cmd_option(&input, next + 7);
 345                 else
 346                         die("unknown command: %s", next);
 347
 348                 next++;
 349         }
 350
 351         strbuf_release(&input);
 352 }
 353
 354 int cmd_update_ref(int argc, const char **argv, const char *prefix)
 355 {
 356         const char *refname, *oldval;
 357         struct object_id oid, oldoid;
 358         int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0;
 359         unsigned int flags = 0;
 360         int create_reflog = 0;
 361         struct option options[] = {
 362                 OPT_STRING( 'm', NULL, &msg, N_("reason"), N_("reason of the update")),
 363                 OPT_BOOL('d', NULL, &delete, N_("delete the reference")),
 364                 OPT_BOOL( 0 , "no-deref", &no_deref,
 365                                         N_("update <refname> not the one it points to")),
 366                 OPT_BOOL('z', NULL, &end_null, N_("stdin has NUL-terminated arguments")),
 367                 OPT_BOOL( 0 , "stdin", &read_stdin, N_("read updates from stdin")),
 368                 OPT_BOOL( 0 , "create-reflog", &create_reflog, N_("create a reflog")),
 369                 OPT_END(),
 370         };
 371
 372         git_config(git_default_config, NULL);
 373         argc = parse_options(argc, argv, prefix, options, git_update_ref_usage,
 374                              0);
 375         if (msg && !*msg)
 376                 die("Refusing to perform update with empty message.");
 377
 378         create_reflog_flag = create_reflog ? REF_FORCE_CREATE_REFLOG : 0;
 379
 380         if (read_stdin) {
 381                 struct strbuf err = STRBUF_INIT;
 382                 struct ref_transaction *transaction;
 383
 384                 transaction = ref_transaction_begin(&err);
 385                 if (!transaction)
 386                         die("%s", err.buf);
 387                 if (delete || no_deref || argc > 0)
 388                         usage_with_options(git_update_ref_usage, options);
 389                 if (end_null)
 390                         line_termination = '\0';
 391                 update_refs_stdin(transaction);
 392                 if (ref_transaction_commit(transaction, &err))
 393                         die("%s", err.buf);
 394                 ref_transaction_free(transaction);
 395                 strbuf_release(&err);
 396                 return 0;
 397         }
 398
 399         if (end_null)
 400                 usage_with_options(git_update_ref_usage, options);
 401
 402         if (delete) {
 403                 if (argc < 1 || argc > 2)
 404                         usage_with_options(git_update_ref_usage, options);
 405                 refname = argv[0];
 406                 oldval = argv[1];
 407         } else {
 408                 const char *value;
 409                 if (argc < 2 || argc > 3)
 410                         usage_with_options(git_update_ref_usage, options);
 411                 refname = argv[0];
 412                 value = argv[1];
 413                 oldval = argv[2];
 414                 if (get_oid(value, &oid))
 415                         die("%s: not a valid SHA1", value);
 416         }
 417
 418         if (oldval) {
 419                 if (!*oldval)
 420                         /*
 421                          * The empty string implies that the reference
 422                          * must not already exist:
 423                          */
 424                         oidclr(&oldoid);
 425                 else if (get_oid(oldval, &oldoid))
 426                         die("%s: not a valid old SHA1", oldval);
 427         }
 428
 429         if (no_deref)
 430                 flags = REF_NO_DEREF;
 431         if (delete)
 432                 /*
 433                  * For purposes of backwards compatibility, we treat
 434                  * NULL_SHA1 as "don't care" here:
 435                  */
 436                 return delete_ref(msg, refname,
 437                                   (oldval && !is_null_oid(&oldoid)) ? &oldoid : NULL,
 438                                   flags);
 439         else
 440                 return update_ref(msg, refname, &oid, oldval ? &oldoid : NULL,
 441                                   flags | create_reflog_flag,
 442                                   UPDATE_REFS_DIE_ON_ERR);
 443 }