sha1_name.c

   1 #include "cache.h"
   2 #include "tag.h"
   3 #include "commit.h"
   4 #include "tree.h"
   5 #include "blob.h"
   6 #include "tree-walk.h"
   7 #include "refs.h"
   8 #include "remote.h"
   9
  10 static int get_sha1_oneline(const char *, unsigned char *, struct commit_list *);
  11
  12 typedef int (*disambiguate_hint_fn)(const unsigned char *, void *);
  13
  14 struct disambiguate_state {
  15         disambiguate_hint_fn fn;
  16         void *cb_data;
  17         unsigned char candidate[20];
  18         unsigned candidate_exists:1;
  19         unsigned candidate_checked:1;
  20         unsigned candidate_ok:1;
  21         unsigned disambiguate_fn_used:1;
  22         unsigned ambiguous:1;
  23         unsigned always_call_fn:1;
  24 };
  25
  26 static void update_candidates(struct disambiguate_state *ds, const unsigned char *current)
  27 {
  28         if (ds->always_call_fn) {
  29                 ds->ambiguous = ds->fn(current, ds->cb_data) ? 1 : 0;
  30                 return;
  31         }
  32         if (!ds->candidate_exists) {
  33                 /* this is the first candidate */
  34                 hashcpy(ds->candidate, current);
  35                 ds->candidate_exists = 1;
  36                 return;
  37         } else if (!hashcmp(ds->candidate, current)) {
  38                 /* the same as what we already have seen */
  39                 return;
  40         }
  41
  42         if (!ds->fn) {
  43                 /* cannot disambiguate between ds->candidate and current */
  44                 ds->ambiguous = 1;
  45                 return;
  46         }
  47
  48         if (!ds->candidate_checked) {
  49                 ds->candidate_ok = ds->fn(ds->candidate, ds->cb_data);
  50                 ds->disambiguate_fn_used = 1;
  51                 ds->candidate_checked = 1;
  52         }
  53
  54         if (!ds->candidate_ok) {
  55                 /* discard the candidate; we know it does not satisify fn */
  56                 hashcpy(ds->candidate, current);
  57                 ds->candidate_checked = 0;
  58                 return;
  59         }
  60
  61         /* if we reach this point, we know ds->candidate satisfies fn */
  62         if (ds->fn(current, ds->cb_data)) {
  63                 /*
  64                  * if both current and candidate satisfy fn, we cannot
  65                  * disambiguate.
  66                  */
  67                 ds->candidate_ok = 0;
  68                 ds->ambiguous = 1;
  69         }
  70
  71         /* otherwise, current can be discarded and candidate is still good */
  72 }
  73
  74 static void find_short_object_filename(int len, const char *hex_pfx, struct disambiguate_state *ds)
  75 {
  76         struct alternate_object_database *alt;
  77         char hex[40];
  78         static struct alternate_object_database *fakeent;
  79
  80         if (!fakeent) {
  81                 /*
  82                  * Create a "fake" alternate object database that
  83                  * points to our own object database, to make it
  84                  * easier to get a temporary working space in
  85                  * alt->name/alt->base while iterating over the
  86                  * object databases including our own.
  87                  */
  88                 const char *objdir = get_object_directory();
  89                 int objdir_len = strlen(objdir);
  90                 int entlen = objdir_len + 43;
  91                 fakeent = xmalloc(sizeof(*fakeent) + entlen);
  92                 memcpy(fakeent->base, objdir, objdir_len);
  93                 fakeent->name = fakeent->base + objdir_len + 1;
  94                 fakeent->name[-1] = '/';
  95         }
  96         fakeent->next = alt_odb_list;
  97
  98         sprintf(hex, "%.2s", hex_pfx);
  99         for (alt = fakeent; alt && !ds->ambiguous; alt = alt->next) {
 100                 struct dirent *de;
 101                 DIR *dir;
 102                 sprintf(alt->name, "%.2s/", hex_pfx);
 103                 dir = opendir(alt->base);
 104                 if (!dir)
 105                         continue;
 106
 107                 while (!ds->ambiguous && (de = readdir(dir)) != NULL) {
 108                         unsigned char sha1[20];
 109
 110                         if (strlen(de->d_name) != 38)
 111                                 continue;
 112                         if (memcmp(de->d_name, hex_pfx + 2, len - 2))
 113                                 continue;
 114                         memcpy(hex + 2, de->d_name, 38);
 115                         if (!get_sha1_hex(hex, sha1))
 116                                 update_candidates(ds, sha1);
 117                 }
 118                 closedir(dir);
 119         }
 120 }
 121
 122 static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
 123 {
 124         do {
 125                 if (*a != *b)
 126                         return 0;
 127                 a++;
 128                 b++;
 129                 len -= 2;
 130         } while (len > 1);
 131         if (len)
 132                 if ((*a ^ *b) & 0xf0)
 133                         return 0;
 134         return 1;
 135 }
 136
 137 static void unique_in_pack(int len,
 138                           const unsigned char *bin_pfx,
 139                            struct packed_git *p,
 140                            struct disambiguate_state *ds)
 141 {
 142         uint32_t num, last, i, first = 0;
 143         const unsigned char *current = NULL;
 144
 145         open_pack_index(p);
 146         num = p->num_objects;
 147         last = num;
 148         while (first < last) {
 149                 uint32_t mid = (first + last) / 2;
 150                 const unsigned char *current;
 151                 int cmp;
 152
 153                 current = nth_packed_object_sha1(p, mid);
 154                 cmp = hashcmp(bin_pfx, current);
 155                 if (!cmp) {
 156                         first = mid;
 157                         break;
 158                 }
 159                 if (cmp > 0) {
 160                         first = mid+1;
 161                         continue;
 162                 }
 163                 last = mid;
 164         }
 165
 166         /*
 167          * At this point, "first" is the location of the lowest object
 168          * with an object name that could match "bin_pfx".  See if we have
 169          * 0, 1 or more objects that actually match(es).
 170          */
 171         for (i = first; i < num && !ds->ambiguous; i++) {
 172                 current = nth_packed_object_sha1(p, i);
 173                 if (!match_sha(len, bin_pfx, current))
 174                         break;
 175                 update_candidates(ds, current);
 176         }
 177 }
 178
 179 static void find_short_packed_object(int len, const unsigned char *bin_pfx,
 180                                      struct disambiguate_state *ds)
 181 {
 182         struct packed_git *p;
 183
 184         prepare_packed_git();
 185         for (p = packed_git; p && !ds->ambiguous; p = p->next)
 186                 unique_in_pack(len, bin_pfx, p, ds);
 187 }
 188
 189 #define SHORT_NAME_NOT_FOUND (-1)
 190 #define SHORT_NAME_AMBIGUOUS (-2)
 191
 192 static int finish_object_disambiguation(struct disambiguate_state *ds,
 193                                         unsigned char *sha1)
 194 {
 195         if (ds->ambiguous)
 196                 return SHORT_NAME_AMBIGUOUS;
 197
 198         if (!ds->candidate_exists)
 199                 return SHORT_NAME_NOT_FOUND;
 200
 201         if (!ds->candidate_checked)
 202                 /*
 203                  * If this is the only candidate, there is no point
 204                  * calling the disambiguation hint callback.
 205                  *
 206                  * On the other hand, if the current candidate
 207                  * replaced an earlier candidate that did _not_ pass
 208                  * the disambiguation hint callback, then we do have
 209                  * more than one objects that match the short name
 210                  * given, so we should make sure this one matches;
 211                  * otherwise, if we discovered this one and the one
 212                  * that we previously discarded in the reverse order,
 213                  * we would end up showing different results in the
 214                  * same repository!
 215                  */
 216                 ds->candidate_ok = (!ds->disambiguate_fn_used ||
 217                                     ds->fn(ds->candidate, ds->cb_data));
 218
 219         if (!ds->candidate_ok)
 220                 return SHORT_NAME_AMBIGUOUS;
 221
 222         hashcpy(sha1, ds->candidate);
 223         return 0;
 224 }
 225
 226 static int disambiguate_commit_only(const unsigned char *sha1, void *cb_data_unused)
 227 {
 228         int kind = sha1_object_info(sha1, NULL);
 229         return kind == OBJ_COMMIT;
 230 }
 231
 232 static int disambiguate_committish_only(const unsigned char *sha1, void *cb_data_unused)
 233 {
 234         struct object *obj;
 235         int kind;
 236
 237         kind = sha1_object_info(sha1, NULL);
 238         if (kind == OBJ_COMMIT)
 239                 return 1;
 240         if (kind != OBJ_TAG)
 241                 return 0;
 242
 243         /* We need to do this the hard way... */
 244         obj = deref_tag(lookup_object(sha1), NULL, 0);
 245         if (obj && obj->type == OBJ_COMMIT)
 246                 return 1;
 247         return 0;
 248 }
 249
 250 static int disambiguate_tree_only(const unsigned char *sha1, void *cb_data_unused)
 251 {
 252         int kind = sha1_object_info(sha1, NULL);
 253         return kind == OBJ_TREE;
 254 }
 255
 256 static int disambiguate_treeish_only(const unsigned char *sha1, void *cb_data_unused)
 257 {
 258         struct object *obj;
 259         int kind;
 260
 261         kind = sha1_object_info(sha1, NULL);
 262         if (kind == OBJ_TREE || kind == OBJ_COMMIT)
 263                 return 1;
 264         if (kind != OBJ_TAG)
 265                 return 0;
 266
 267         /* We need to do this the hard way... */
 268         obj = deref_tag(lookup_object(sha1), NULL, 0);
 269         if (obj && (obj->type == OBJ_TREE || obj->type == OBJ_COMMIT))
 270                 return 1;
 271         return 0;
 272 }
 273
 274 static int disambiguate_blob_only(const unsigned char *sha1, void *cb_data_unused)
 275 {
 276         int kind = sha1_object_info(sha1, NULL);
 277         return kind == OBJ_BLOB;
 278 }
 279
 280 static int prepare_prefixes(const char *name, int len,
 281                             unsigned char *bin_pfx,
 282                             char *hex_pfx)
 283 {
 284         int i;
 285
 286         hashclr(bin_pfx);
 287         memset(hex_pfx, 'x', 40);
 288         for (i = 0; i < len ;i++) {
 289                 unsigned char c = name[i];
 290                 unsigned char val;
 291                 if (c >= '0' && c <= '9')
 292                         val = c - '0';
 293                 else if (c >= 'a' && c <= 'f')
 294                         val = c - 'a' + 10;
 295                 else if (c >= 'A' && c <='F') {
 296                         val = c - 'A' + 10;
 297                         c -= 'A' - 'a';
 298                 }
 299                 else
 300                         return -1;
 301                 hex_pfx[i] = c;
 302                 if (!(i & 1))
 303                         val <<= 4;
 304                 bin_pfx[i >> 1] |= val;
 305         }
 306         return 0;
 307 }
 308
 309 static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 310                           unsigned flags)
 311 {
 312         int status;
 313         char hex_pfx[40];
 314         unsigned char bin_pfx[20];
 315         struct disambiguate_state ds;
 316         int quietly = !!(flags & GET_SHA1_QUIETLY);
 317
 318         if (len < MINIMUM_ABBREV || len > 40)
 319                 return -1;
 320         if (prepare_prefixes(name, len, bin_pfx, hex_pfx) < 0)
 321                 return -1;
 322
 323         prepare_alt_odb();
 324
 325         memset(&ds, 0, sizeof(ds));
 326         if (flags & GET_SHA1_COMMIT)
 327                 ds.fn = disambiguate_commit_only;
 328         else if (flags & GET_SHA1_COMMITTISH)
 329                 ds.fn = disambiguate_committish_only;
 330         else if (flags & GET_SHA1_TREE)
 331                 ds.fn = disambiguate_tree_only;
 332         else if (flags & GET_SHA1_TREEISH)
 333                 ds.fn = disambiguate_treeish_only;
 334         else if (flags & GET_SHA1_BLOB)
 335                 ds.fn = disambiguate_blob_only;
 336
 337         find_short_object_filename(len, hex_pfx, &ds);
 338         find_short_packed_object(len, bin_pfx, &ds);
 339         status = finish_object_disambiguation(&ds, sha1);
 340
 341         if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
 342                 return error("short SHA1 %.*s is ambiguous.", len, hex_pfx);
 343         return status;
 344 }
 345
 346
 347 int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
 348 {
 349         char hex_pfx[40];
 350         unsigned char bin_pfx[20];
 351         struct disambiguate_state ds;
 352         int len = strlen(prefix);
 353
 354         if (len < MINIMUM_ABBREV || len > 40)
 355                 return -1;
 356         if (prepare_prefixes(prefix, len, bin_pfx, hex_pfx) < 0)
 357                 return -1;
 358
 359         prepare_alt_odb();
 360
 361         memset(&ds, 0, sizeof(ds));
 362         ds.always_call_fn = 1;
 363         ds.cb_data = cb_data;
 364         ds.fn = fn;
 365
 366         find_short_object_filename(len, hex_pfx, &ds);
 367         find_short_packed_object(len, bin_pfx, &ds);
 368         return ds.ambiguous;
 369 }
 370
 371 const char *find_unique_abbrev(const unsigned char *sha1, int len)
 372 {
 373         int status, exists;
 374         static char hex[41];
 375
 376         exists = has_sha1_file(sha1);
 377         memcpy(hex, sha1_to_hex(sha1), 40);
 378         if (len == 40 || !len)
 379                 return hex;
 380         while (len < 40) {
 381                 unsigned char sha1_ret[20];
 382                 status = get_short_sha1(hex, len, sha1_ret, GET_SHA1_QUIETLY);
 383                 if (exists
 384                     ? !status
 385                     : status == SHORT_NAME_NOT_FOUND) {
 386                         hex[len] = 0;
 387                         return hex;
 388                 }
 389                 len++;
 390         }
 391         return hex;
 392 }
 393
 394 static int ambiguous_path(const char *path, int len)
 395 {
 396         int slash = 1;
 397         int cnt;
 398
 399         for (cnt = 0; cnt < len; cnt++) {
 400                 switch (*path++) {
 401                 case '\0':
 402                         break;
 403                 case '/':
 404                         if (slash)
 405                                 break;
 406                         slash = 1;
 407                         continue;
 408                 case '.':
 409                         continue;
 410                 default:
 411                         slash = 0;
 412                         continue;
 413                 }
 414                 break;
 415         }
 416         return slash;
 417 }
 418
 419 static inline int upstream_mark(const char *string, int len)
 420 {
 421         const char *suffix[] = { "@{upstream}", "@{u}" };
 422         int i;
 423
 424         for (i = 0; i < ARRAY_SIZE(suffix); i++) {
 425                 int suffix_len = strlen(suffix[i]);
 426                 if (suffix_len <= len
 427                     && !memcmp(string, suffix[i], suffix_len))
 428                         return suffix_len;
 429         }
 430         return 0;
 431 }
 432
 433 static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags);
 434
 435 static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 436 {
 437         static const char *warn_msg = "refname '%.*s' is ambiguous.";
 438         static const char *object_name_msg = N_(
 439         "Git normally never creates a ref that ends with 40 hex characters\n"
 440         "because it will be ignored when you just specify 40-hex. These refs\n"
 441         "may be created by mistake. For example,\n"
 442         "\n"
 443         "  git checkout -b $br $(git rev-parse ...)\n"
 444         "\n"
 445         "where \"$br\" is somehow empty and a 40-hex ref is created. Please\n"
 446         "examine these refs and maybe delete them. Turn this message off by\n"
 447         "running \"git config advice.object_name_warning false\"");
 448         unsigned char tmp_sha1[20];
 449         char *real_ref = NULL;
 450         int refs_found = 0;
 451         int at, reflog_len;
 452
 453         if (len == 40 && !get_sha1_hex(str, sha1)) {
 454                 refs_found = dwim_ref(str, len, tmp_sha1, &real_ref);
 455                 if (refs_found > 0 && warn_ambiguous_refs) {
 456                         warning(warn_msg, len, str);
 457                         if (advice_object_name_warning)
 458                                 fprintf(stderr, "%s\n", _(object_name_msg));
 459                 }
 460                 free(real_ref);
 461                 return 0;
 462         }
 463
 464         /* basic@{time or number or -number} format to query ref-log */
 465         reflog_len = at = 0;
 466         if (len && str[len-1] == '}') {
 467                 for (at = len-2; at >= 0; at--) {
 468                         if (str[at] == '@' && str[at+1] == '{') {
 469                                 if (!upstream_mark(str + at, len - at)) {
 470                                         reflog_len = (len-1) - (at+2);
 471                                         len = at;
 472                                 }
 473                                 break;
 474                         }
 475                 }
 476         }
 477
 478         /* Accept only unambiguous ref paths. */
 479         if (len && ambiguous_path(str, len))
 480                 return -1;
 481
 482         if (!len && reflog_len) {
 483                 struct strbuf buf = STRBUF_INIT;
 484                 int ret;
 485                 /* try the @{-N} syntax for n-th checkout */
 486                 ret = interpret_branch_name(str+at, &buf);
 487                 if (ret > 0) {
 488                         /* substitute this branch name and restart */
 489                         return get_sha1_1(buf.buf, buf.len, sha1, 0);
 490                 } else if (ret == 0) {
 491                         return -1;
 492                 }
 493                 /* allow "@{...}" to mean the current branch reflog */
 494                 refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
 495         } else if (reflog_len)
 496                 refs_found = dwim_log(str, len, sha1, &real_ref);
 497         else
 498                 refs_found = dwim_ref(str, len, sha1, &real_ref);
 499
 500         if (!refs_found)
 501                 return -1;
 502
 503         if (warn_ambiguous_refs &&
 504             (refs_found > 1 ||
 505              !get_short_sha1(str, len, tmp_sha1, GET_SHA1_QUIETLY)))
 506                 warning(warn_msg, len, str);
 507
 508         if (reflog_len) {
 509                 int nth, i;
 510                 unsigned long at_time;
 511                 unsigned long co_time;
 512                 int co_tz, co_cnt;
 513
 514                 /* a @{-N} placed anywhere except the start is an error */
 515                 if (str[at+2] == '-')
 516                         return -1;
 517
 518                 /* Is it asking for N-th entry, or approxidate? */
 519                 for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 520                         char ch = str[at+2+i];
 521                         if ('0' <= ch && ch <= '9')
 522                                 nth = nth * 10 + ch - '0';
 523                         else
 524                                 nth = -1;
 525                 }
 526                 if (100000000 <= nth) {
 527                         at_time = nth;
 528                         nth = -1;
 529                 } else if (0 <= nth)
 530                         at_time = 0;
 531                 else {
 532                         int errors = 0;
 533                         char *tmp = xstrndup(str + at + 2, reflog_len);
 534                         at_time = approxidate_careful(tmp, &errors);
 535                         free(tmp);
 536                         if (errors)
 537                                 return -1;
 538                 }
 539                 if (read_ref_at(real_ref, at_time, nth, sha1, NULL,
 540                                 &co_time, &co_tz, &co_cnt)) {
 541                         if (!len) {
 542                                 if (!prefixcmp(real_ref, "refs/heads/")) {
 543                                         str = real_ref + 11;
 544                                         len = strlen(real_ref + 11);
 545                                 } else {
 546                                         /* detached HEAD */
 547                                         str = "HEAD";
 548                                         len = 4;
 549                                 }
 550                         }
 551                         if (at_time)
 552                                 warning("Log for '%.*s' only goes "
 553                                         "back to %s.", len, str,
 554                                         show_date(co_time, co_tz, DATE_RFC2822));
 555                         else {
 556                                 die("Log for '%.*s' only has %d entries.",
 557                                     len, str, co_cnt);
 558                         }
 559                 }
 560         }
 561
 562         free(real_ref);
 563         return 0;
 564 }
 565
 566 static int get_parent(const char *name, int len,
 567                       unsigned char *result, int idx)
 568 {
 569         unsigned char sha1[20];
 570         int ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 571         struct commit *commit;
 572         struct commit_list *p;
 573
 574         if (ret)
 575                 return ret;
 576         commit = lookup_commit_reference(sha1);
 577         if (!commit)
 578                 return -1;
 579         if (parse_commit(commit))
 580                 return -1;
 581         if (!idx) {
 582                 hashcpy(result, commit->object.sha1);
 583                 return 0;
 584         }
 585         p = commit->parents;
 586         while (p) {
 587                 if (!--idx) {
 588                         hashcpy(result, p->item->object.sha1);
 589                         return 0;
 590                 }
 591                 p = p->next;
 592         }
 593         return -1;
 594 }
 595
 596 static int get_nth_ancestor(const char *name, int len,
 597                             unsigned char *result, int generation)
 598 {
 599         unsigned char sha1[20];
 600         struct commit *commit;
 601         int ret;
 602
 603         ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 604         if (ret)
 605                 return ret;
 606         commit = lookup_commit_reference(sha1);
 607         if (!commit)
 608                 return -1;
 609
 610         while (generation--) {
 611                 if (parse_commit(commit) || !commit->parents)
 612                         return -1;
 613                 commit = commit->parents->item;
 614         }
 615         hashcpy(result, commit->object.sha1);
 616         return 0;
 617 }
 618
 619 struct object *peel_to_type(const char *name, int namelen,
 620                             struct object *o, enum object_type expected_type)
 621 {
 622         if (name && !namelen)
 623                 namelen = strlen(name);
 624         while (1) {
 625                 if (!o || (!o->parsed && !parse_object(o->sha1)))
 626                         return NULL;
 627                 if (expected_type == OBJ_ANY || o->type == expected_type)
 628                         return o;
 629                 if (o->type == OBJ_TAG)
 630                         o = ((struct tag*) o)->tagged;
 631                 else if (o->type == OBJ_COMMIT)
 632                         o = &(((struct commit *) o)->tree->object);
 633                 else {
 634                         if (name)
 635                                 error("%.*s: expected %s type, but the object "
 636                                       "dereferences to %s type",
 637                                       namelen, name, typename(expected_type),
 638                                       typename(o->type));
 639                         return NULL;
 640                 }
 641         }
 642 }
 643
 644 static int peel_onion(const char *name, int len, unsigned char *sha1)
 645 {
 646         unsigned char outer[20];
 647         const char *sp;
 648         unsigned int expected_type = 0;
 649         unsigned lookup_flags = 0;
 650         struct object *o;
 651
 652         /*
 653          * "ref^{type}" dereferences ref repeatedly until you cannot
 654          * dereference anymore, or you get an object of given type,
 655          * whichever comes first.  "ref^{}" means just dereference
 656          * tags until you get a non-tag.  "ref^0" is a shorthand for
 657          * "ref^{commit}".  "commit^{tree}" could be used to find the
 658          * top-level tree of the given commit.
 659          */
 660         if (len < 4 || name[len-1] != '}')
 661                 return -1;
 662
 663         for (sp = name + len - 1; name <= sp; sp--) {
 664                 int ch = *sp;
 665                 if (ch == '{' && name < sp && sp[-1] == '^')
 666                         break;
 667         }
 668         if (sp <= name)
 669                 return -1;
 670
 671         sp++; /* beginning of type name, or closing brace for empty */
 672         if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
 673                 expected_type = OBJ_COMMIT;
 674         else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
 675                 expected_type = OBJ_TREE;
 676         else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
 677                 expected_type = OBJ_BLOB;
 678         else if (!prefixcmp(sp, "object}"))
 679                 expected_type = OBJ_ANY;
 680         else if (sp[0] == '}')
 681                 expected_type = OBJ_NONE;
 682         else if (sp[0] == '/')
 683                 expected_type = OBJ_COMMIT;
 684         else
 685                 return -1;
 686
 687         if (expected_type == OBJ_COMMIT)
 688                 lookup_flags = GET_SHA1_COMMITTISH;
 689         else if (expected_type == OBJ_TREE)
 690                 lookup_flags = GET_SHA1_TREEISH;
 691
 692         if (get_sha1_1(name, sp - name - 2, outer, lookup_flags))
 693                 return -1;
 694
 695         o = parse_object(outer);
 696         if (!o)
 697                 return -1;
 698         if (!expected_type) {
 699                 o = deref_tag(o, name, sp - name - 2);
 700                 if (!o || (!o->parsed && !parse_object(o->sha1)))
 701                         return -1;
 702                 hashcpy(sha1, o->sha1);
 703                 return 0;
 704         }
 705
 706         /*
 707          * At this point, the syntax look correct, so
 708          * if we do not get the needed object, we should
 709          * barf.
 710          */
 711         o = peel_to_type(name, len, o, expected_type);
 712         if (!o)
 713                 return -1;
 714
 715         hashcpy(sha1, o->sha1);
 716         if (sp[0] == '/') {
 717                 /* "$commit^{/foo}" */
 718                 char *prefix;
 719                 int ret;
 720                 struct commit_list *list = NULL;
 721
 722                 /*
 723                  * $commit^{/}. Some regex implementation may reject.
 724                  * We don't need regex anyway. '' pattern always matches.
 725                  */
 726                 if (sp[1] == '}')
 727                         return 0;
 728
 729                 prefix = xstrndup(sp + 1, name + len - 1 - (sp + 1));
 730                 commit_list_insert((struct commit *)o, &list);
 731                 ret = get_sha1_oneline(prefix, sha1, list);
 732                 free(prefix);
 733                 return ret;
 734         }
 735         return 0;
 736 }
 737
 738 static int get_describe_name(const char *name, int len, unsigned char *sha1)
 739 {
 740         const char *cp;
 741         unsigned flags = GET_SHA1_QUIETLY | GET_SHA1_COMMIT;
 742
 743         for (cp = name + len - 1; name + 2 <= cp; cp--) {
 744                 char ch = *cp;
 745                 if (hexval(ch) & ~0377) {
 746                         /* We must be looking at g in "SOMETHING-g"
 747                          * for it to be describe output.
 748                          */
 749                         if (ch == 'g' && cp[-1] == '-') {
 750                                 cp++;
 751                                 len -= cp - name;
 752                                 return get_short_sha1(cp, len, sha1, flags);
 753                         }
 754                 }
 755         }
 756         return -1;
 757 }
 758
 759 static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags)
 760 {
 761         int ret, has_suffix;
 762         const char *cp;
 763
 764         /*
 765          * "name~3" is "name^^^", "name~" is "name~1", and "name^" is "name^1".
 766          */
 767         has_suffix = 0;
 768         for (cp = name + len - 1; name <= cp; cp--) {
 769                 int ch = *cp;
 770                 if ('0' <= ch && ch <= '9')
 771                         continue;
 772                 if (ch == '~' || ch == '^')
 773                         has_suffix = ch;
 774                 break;
 775         }
 776
 777         if (has_suffix) {
 778                 int num = 0;
 779                 int len1 = cp - name;
 780                 cp++;
 781                 while (cp < name + len)
 782                         num = num * 10 + *cp++ - '0';
 783                 if (!num && len1 == len - 1)
 784                         num = 1;
 785                 if (has_suffix == '^')
 786                         return get_parent(name, len1, sha1, num);
 787                 /* else if (has_suffix == '~') -- goes without saying */
 788                 return get_nth_ancestor(name, len1, sha1, num);
 789         }
 790
 791         ret = peel_onion(name, len, sha1);
 792         if (!ret)
 793                 return 0;
 794
 795         ret = get_sha1_basic(name, len, sha1);
 796         if (!ret)
 797                 return 0;
 798
 799         /* It could be describe output that is "SOMETHING-gXXXX" */
 800         ret = get_describe_name(name, len, sha1);
 801         if (!ret)
 802                 return 0;
 803
 804         return get_short_sha1(name, len, sha1, lookup_flags);
 805 }
 806
 807 /*
 808  * This interprets names like ':/Initial revision of "git"' by searching
 809  * through history and returning the first commit whose message starts
 810  * the given regular expression.
 811  *
 812  * For future extension, ':/!' is reserved. If you want to match a message
 813  * beginning with a '!', you have to repeat the exclamation mark.
 814  */
 815 #define ONELINE_SEEN (1u<<20)
 816
 817 static int handle_one_ref(const char *path,
 818                 const unsigned char *sha1, int flag, void *cb_data)
 819 {
 820         struct commit_list **list = cb_data;
 821         struct object *object = parse_object(sha1);
 822         if (!object)
 823                 return 0;
 824         if (object->type == OBJ_TAG) {
 825                 object = deref_tag(object, path, strlen(path));
 826                 if (!object)
 827                         return 0;
 828         }
 829         if (object->type != OBJ_COMMIT)
 830                 return 0;
 831         commit_list_insert_by_date((struct commit *)object, list);
 832         return 0;
 833 }
 834
 835 static int get_sha1_oneline(const char *prefix, unsigned char *sha1,
 836                             struct commit_list *list)
 837 {
 838         struct commit_list *backup = NULL, *l;
 839         int found = 0;
 840         regex_t regex;
 841
 842         if (prefix[0] == '!') {
 843                 if (prefix[1] != '!')
 844                         die ("Invalid search pattern: %s", prefix);
 845                 prefix++;
 846         }
 847
 848         if (regcomp(&regex, prefix, REG_EXTENDED))
 849                 die("Invalid search pattern: %s", prefix);
 850
 851         for (l = list; l; l = l->next) {
 852                 l->item->object.flags |= ONELINE_SEEN;
 853                 commit_list_insert(l->item, &backup);
 854         }
 855         while (list) {
 856                 char *p, *to_free = NULL;
 857                 struct commit *commit;
 858                 enum object_type type;
 859                 unsigned long size;
 860                 int matches;
 861
 862                 commit = pop_most_recent_commit(&list, ONELINE_SEEN);
 863                 if (!parse_object(commit->object.sha1))
 864                         continue;
 865                 if (commit->buffer)
 866                         p = commit->buffer;
 867                 else {
 868                         p = read_sha1_file(commit->object.sha1, &type, &size);
 869                         if (!p)
 870                                 continue;
 871                         to_free = p;
 872                 }
 873
 874                 p = strstr(p, "\n\n");
 875                 matches = p && !regexec(&regex, p + 2, 0, NULL, 0);
 876                 free(to_free);
 877
 878                 if (matches) {
 879                         hashcpy(sha1, commit->object.sha1);
 880                         found = 1;
 881                         break;
 882                 }
 883         }
 884         regfree(&regex);
 885         free_commit_list(list);
 886         for (l = backup; l; l = l->next)
 887                 clear_commit_marks(l->item, ONELINE_SEEN);
 888         free_commit_list(backup);
 889         return found ? 0 : -1;
 890 }
 891
 892 struct grab_nth_branch_switch_cbdata {
 893         int remaining;
 894         struct strbuf buf;
 895 };
 896
 897 static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
 898                                   const char *email, unsigned long timestamp, int tz,
 899                                   const char *message, void *cb_data)
 900 {
 901         struct grab_nth_branch_switch_cbdata *cb = cb_data;
 902         const char *match = NULL, *target = NULL;
 903         size_t len;
 904
 905         if (!prefixcmp(message, "checkout: moving from ")) {
 906                 match = message + strlen("checkout: moving from ");
 907                 target = strstr(match, " to ");
 908         }
 909
 910         if (!match || !target)
 911                 return 0;
 912         if (--(cb->remaining) == 0) {
 913                 len = target - match;
 914                 strbuf_reset(&cb->buf);
 915                 strbuf_add(&cb->buf, match, len);
 916                 return 1; /* we are done */
 917         }
 918         return 0;
 919 }
 920
 921 /*
 922  * Parse @{-N} syntax, return the number of characters parsed
 923  * if successful; otherwise signal an error with negative value.
 924  */
 925 static int interpret_nth_prior_checkout(const char *name, struct strbuf *buf)
 926 {
 927         long nth;
 928         int retval;
 929         struct grab_nth_branch_switch_cbdata cb;
 930         const char *brace;
 931         char *num_end;
 932
 933         if (name[0] != '@' || name[1] != '{' || name[2] != '-')
 934                 return -1;
 935         brace = strchr(name, '}');
 936         if (!brace)
 937                 return -1;
 938         nth = strtol(name + 3, &num_end, 10);
 939         if (num_end != brace)
 940                 return -1;
 941         if (nth <= 0)
 942                 return -1;
 943         cb.remaining = nth;
 944         strbuf_init(&cb.buf, 20);
 945
 946         retval = 0;
 947         if (0 < for_each_reflog_ent_reverse("HEAD", grab_nth_branch_switch, &cb)) {
 948                 strbuf_reset(buf);
 949                 strbuf_add(buf, cb.buf.buf, cb.buf.len);
 950                 retval = brace - name + 1;
 951         }
 952
 953         strbuf_release(&cb.buf);
 954         return retval;
 955 }
 956
 957 int get_sha1_mb(const char *name, unsigned char *sha1)
 958 {
 959         struct commit *one, *two;
 960         struct commit_list *mbs;
 961         unsigned char sha1_tmp[20];
 962         const char *dots;
 963         int st;
 964
 965         dots = strstr(name, "...");
 966         if (!dots)
 967                 return get_sha1(name, sha1);
 968         if (dots == name)
 969                 st = get_sha1("HEAD", sha1_tmp);
 970         else {
 971                 struct strbuf sb;
 972                 strbuf_init(&sb, dots - name);
 973                 strbuf_add(&sb, name, dots - name);
 974                 st = get_sha1_committish(sb.buf, sha1_tmp);
 975                 strbuf_release(&sb);
 976         }
 977         if (st)
 978                 return st;
 979         one = lookup_commit_reference_gently(sha1_tmp, 0);
 980         if (!one)
 981                 return -1;
 982
 983         if (get_sha1_committish(dots[3] ? (dots + 3) : "HEAD", sha1_tmp))
 984                 return -1;
 985         two = lookup_commit_reference_gently(sha1_tmp, 0);
 986         if (!two)
 987                 return -1;
 988         mbs = get_merge_bases(one, two, 1);
 989         if (!mbs || mbs->next)
 990                 st = -1;
 991         else {
 992                 st = 0;
 993                 hashcpy(sha1, mbs->item->object.sha1);
 994         }
 995         free_commit_list(mbs);
 996         return st;
 997 }
 998
 999 /*
1000  * This reads short-hand syntax that not only evaluates to a commit
1001  * object name, but also can act as if the end user spelled the name
1002  * of the branch from the command line.
1003  *
1004  * - "@{-N}" finds the name of the Nth previous branch we were on, and
1005  *   places the name of the branch in the given buf and returns the
1006  *   number of characters parsed if successful.
1007  *
1008  * - "<branch>@{upstream}" finds the name of the other ref that
1009  *   <branch> is configured to merge with (missing <branch> defaults
1010  *   to the current branch), and places the name of the branch in the
1011  *   given buf and returns the number of characters parsed if
1012  *   successful.
1013  *
1014  * If the input is not of the accepted format, it returns a negative
1015  * number to signal an error.
1016  *
1017  * If the input was ok but there are not N branch switches in the
1018  * reflog, it returns 0.
1019  */
1020 int interpret_branch_name(const char *name, struct strbuf *buf)
1021 {
1022         char *cp;
1023         struct branch *upstream;
1024         int namelen = strlen(name);
1025         int len = interpret_nth_prior_checkout(name, buf);
1026         int tmp_len;
1027
1028         if (!len)
1029                 return len; /* syntax Ok, not enough switches */
1030         if (0 < len && len == namelen)
1031                 return len; /* consumed all */
1032         else if (0 < len) {
1033                 /* we have extra data, which might need further processing */
1034                 struct strbuf tmp = STRBUF_INIT;
1035                 int used = buf->len;
1036                 int ret;
1037
1038                 strbuf_add(buf, name + len, namelen - len);
1039                 ret = interpret_branch_name(buf->buf, &tmp);
1040                 /* that data was not interpreted, remove our cruft */
1041                 if (ret < 0) {
1042                         strbuf_setlen(buf, used);
1043                         return len;
1044                 }
1045                 strbuf_reset(buf);
1046                 strbuf_addbuf(buf, &tmp);
1047                 strbuf_release(&tmp);
1048                 /* tweak for size of {-N} versus expanded ref name */
1049                 return ret - used + len;
1050         }
1051
1052         cp = strchr(name, '@');
1053         if (!cp)
1054                 return -1;
1055         tmp_len = upstream_mark(cp, namelen - (cp - name));
1056         if (!tmp_len)
1057                 return -1;
1058         len = cp + tmp_len - name;
1059         cp = xstrndup(name, cp - name);
1060         upstream = branch_get(*cp ? cp : NULL);
1061         /*
1062          * Upstream can be NULL only if cp refers to HEAD and HEAD
1063          * points to something different than a branch.
1064          */
1065         if (!upstream)
1066                 die(_("HEAD does not point to a branch"));
1067         if (!upstream->merge || !upstream->merge[0]->dst) {
1068                 if (!ref_exists(upstream->refname))
1069                         die(_("No such branch: '%s'"), cp);
1070                 if (!upstream->merge) {
1071                         die(_("No upstream configured for branch '%s'"),
1072                                 upstream->name);
1073                 }
1074                 die(
1075                         _("Upstream branch '%s' not stored as a remote-tracking branch"),
1076                         upstream->merge[0]->src);
1077         }
1078         free(cp);
1079         cp = shorten_unambiguous_ref(upstream->merge[0]->dst, 0);
1080         strbuf_reset(buf);
1081         strbuf_addstr(buf, cp);
1082         free(cp);
1083         return len;
1084 }
1085
1086 int strbuf_branchname(struct strbuf *sb, const char *name)
1087 {
1088         int len = strlen(name);
1089         int used = interpret_branch_name(name, sb);
1090
1091         if (used == len)
1092                 return 0;
1093         if (used < 0)
1094                 used = 0;
1095         strbuf_add(sb, name + used, len - used);
1096         return len;
1097 }
1098
1099 int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
1100 {
1101         strbuf_branchname(sb, name);
1102         if (name[0] == '-')
1103                 return -1;
1104         strbuf_splice(sb, 0, 0, "refs/heads/", 11);
1105         return check_refname_format(sb->buf, 0);
1106 }
1107
1108 /*
1109  * This is like "get_sha1_basic()", except it allows "sha1 expressions",
1110  * notably "xyz^" for "parent of xyz"
1111  */
1112 int get_sha1(const char *name, unsigned char *sha1)
1113 {
1114         struct object_context unused;
1115         return get_sha1_with_context(name, 0, sha1, &unused);
1116 }
1117
1118 /*
1119  * Many callers know that the user meant to name a committish by
1120  * syntactical positions where the object name appears.  Calling this
1121  * function allows the machinery to disambiguate shorter-than-unique
1122  * abbreviated object names between committish and others.
1123  *
1124  * Note that this does NOT error out when the named object is not a
1125  * committish. It is merely to give a hint to the disambiguation
1126  * machinery.
1127  */
1128 int get_sha1_committish(const char *name, unsigned char *sha1)
1129 {
1130         struct object_context unused;
1131         return get_sha1_with_context(name, GET_SHA1_COMMITTISH,
1132                                      sha1, &unused);
1133 }
1134
1135 int get_sha1_treeish(const char *name, unsigned char *sha1)
1136 {
1137         struct object_context unused;
1138         return get_sha1_with_context(name, GET_SHA1_TREEISH,
1139                                      sha1, &unused);
1140 }
1141
1142 int get_sha1_commit(const char *name, unsigned char *sha1)
1143 {
1144         struct object_context unused;
1145         return get_sha1_with_context(name, GET_SHA1_COMMIT,
1146                                      sha1, &unused);
1147 }
1148
1149 int get_sha1_tree(const char *name, unsigned char *sha1)
1150 {
1151         struct object_context unused;
1152         return get_sha1_with_context(name, GET_SHA1_TREE,
1153                                      sha1, &unused);
1154 }
1155
1156 int get_sha1_blob(const char *name, unsigned char *sha1)
1157 {
1158         struct object_context unused;
1159         return get_sha1_with_context(name, GET_SHA1_BLOB,
1160                                      sha1, &unused);
1161 }
1162
1163 /* Must be called only when object_name:filename doesn't exist. */
1164 static void diagnose_invalid_sha1_path(const char *prefix,
1165                                        const char *filename,
1166                                        const unsigned char *tree_sha1,
1167                                        const char *object_name,
1168                                        int object_name_len)
1169 {
1170         struct stat st;
1171         unsigned char sha1[20];
1172         unsigned mode;
1173
1174         if (!prefix)
1175                 prefix = "";
1176
1177         if (!lstat(filename, &st))
1178                 die("Path '%s' exists on disk, but not in '%.*s'.",
1179                     filename, object_name_len, object_name);
1180         if (errno == ENOENT || errno == ENOTDIR) {
1181                 char *fullname = xmalloc(strlen(filename)
1182                                              + strlen(prefix) + 1);
1183                 strcpy(fullname, prefix);
1184                 strcat(fullname, filename);
1185
1186                 if (!get_tree_entry(tree_sha1, fullname,
1187                                     sha1, &mode)) {
1188                         die("Path '%s' exists, but not '%s'.\n"
1189                             "Did you mean '%.*s:%s' aka '%.*s:./%s'?",
1190                             fullname,
1191                             filename,
1192                             object_name_len, object_name,
1193                             fullname,
1194                             object_name_len, object_name,
1195                             filename);
1196                 }
1197                 die("Path '%s' does not exist in '%.*s'",
1198                     filename, object_name_len, object_name);
1199         }
1200 }
1201
1202 /* Must be called only when :stage:filename doesn't exist. */
1203 static void diagnose_invalid_index_path(int stage,
1204                                         const char *prefix,
1205                                         const char *filename)
1206 {
1207         struct stat st;
1208         struct cache_entry *ce;
1209         int pos;
1210         unsigned namelen = strlen(filename);
1211         unsigned fullnamelen;
1212         char *fullname;
1213
1214         if (!prefix)
1215                 prefix = "";
1216
1217         /* Wrong stage number? */
1218         pos = cache_name_pos(filename, namelen);
1219         if (pos < 0)
1220                 pos = -pos - 1;
1221         if (pos < active_nr) {
1222                 ce = active_cache[pos];
1223                 if (ce_namelen(ce) == namelen &&
1224                     !memcmp(ce->name, filename, namelen))
1225                         die("Path '%s' is in the index, but not at stage %d.\n"
1226                             "Did you mean ':%d:%s'?",
1227                             filename, stage,
1228                             ce_stage(ce), filename);
1229         }
1230
1231         /* Confusion between relative and absolute filenames? */
1232         fullnamelen = namelen + strlen(prefix);
1233         fullname = xmalloc(fullnamelen + 1);
1234         strcpy(fullname, prefix);
1235         strcat(fullname, filename);
1236         pos = cache_name_pos(fullname, fullnamelen);
1237         if (pos < 0)
1238                 pos = -pos - 1;
1239         if (pos < active_nr) {
1240                 ce = active_cache[pos];
1241                 if (ce_namelen(ce) == fullnamelen &&
1242                     !memcmp(ce->name, fullname, fullnamelen))
1243                         die("Path '%s' is in the index, but not '%s'.\n"
1244                             "Did you mean ':%d:%s' aka ':%d:./%s'?",
1245                             fullname, filename,
1246                             ce_stage(ce), fullname,
1247                             ce_stage(ce), filename);
1248         }
1249
1250         if (!lstat(filename, &st))
1251                 die("Path '%s' exists on disk, but not in the index.", filename);
1252         if (errno == ENOENT || errno == ENOTDIR)
1253                 die("Path '%s' does not exist (neither on disk nor in the index).",
1254                     filename);
1255
1256         free(fullname);
1257 }
1258
1259
1260 static char *resolve_relative_path(const char *rel)
1261 {
1262         if (prefixcmp(rel, "./") && prefixcmp(rel, "../"))
1263                 return NULL;
1264
1265         if (!startup_info)
1266                 die("BUG: startup_info struct is not initialized.");
1267
1268         if (!is_inside_work_tree())
1269                 die("relative path syntax can't be used outside working tree.");
1270
1271         /* die() inside prefix_path() if resolved path is outside worktree */
1272         return prefix_path(startup_info->prefix,
1273                            startup_info->prefix ? strlen(startup_info->prefix) : 0,
1274                            rel);
1275 }
1276
1277 static int get_sha1_with_context_1(const char *name,
1278                                    unsigned flags,
1279                                    const char *prefix,
1280                                    unsigned char *sha1,
1281                                    struct object_context *oc)
1282 {
1283         int ret, bracket_depth;
1284         int namelen = strlen(name);
1285         const char *cp;
1286         int only_to_die = flags & GET_SHA1_ONLY_TO_DIE;
1287
1288         memset(oc, 0, sizeof(*oc));
1289         oc->mode = S_IFINVALID;
1290         ret = get_sha1_1(name, namelen, sha1, flags);
1291         if (!ret)
1292                 return ret;
1293         /*
1294          * sha1:path --> object name of path in ent sha1
1295          * :path -> object name of absolute path in index
1296          * :./path -> object name of path relative to cwd in index
1297          * :[0-3]:path -> object name of path in index at stage
1298          * :/foo -> recent commit matching foo
1299          */
1300         if (name[0] == ':') {
1301                 int stage = 0;
1302                 struct cache_entry *ce;
1303                 char *new_path = NULL;
1304                 int pos;
1305                 if (!only_to_die && namelen > 2 && name[1] == '/') {
1306                         struct commit_list *list = NULL;
1307                         for_each_ref(handle_one_ref, &list);
1308                         return get_sha1_oneline(name + 2, sha1, list);
1309                 }
1310                 if (namelen < 3 ||
1311                     name[2] != ':' ||
1312                     name[1] < '0' || '3' < name[1])
1313                         cp = name + 1;
1314                 else {
1315                         stage = name[1] - '0';
1316                         cp = name + 3;
1317                 }
1318                 new_path = resolve_relative_path(cp);
1319                 if (!new_path) {
1320                         namelen = namelen - (cp - name);
1321                 } else {
1322                         cp = new_path;
1323                         namelen = strlen(cp);
1324                 }
1325
1326                 strncpy(oc->path, cp,
1327                         sizeof(oc->path));
1328                 oc->path[sizeof(oc->path)-1] = '\0';
1329
1330                 if (!active_cache)
1331                         read_cache();
1332                 pos = cache_name_pos(cp, namelen);
1333                 if (pos < 0)
1334                         pos = -pos - 1;
1335                 while (pos < active_nr) {
1336                         ce = active_cache[pos];
1337                         if (ce_namelen(ce) != namelen ||
1338                             memcmp(ce->name, cp, namelen))
1339                                 break;
1340                         if (ce_stage(ce) == stage) {
1341                                 hashcpy(sha1, ce->sha1);
1342                                 oc->mode = ce->ce_mode;
1343                                 free(new_path);
1344                                 return 0;
1345                         }
1346                         pos++;
1347                 }
1348                 if (only_to_die && name[1] && name[1] != '/')
1349                         diagnose_invalid_index_path(stage, prefix, cp);
1350                 free(new_path);
1351                 return -1;
1352         }
1353         for (cp = name, bracket_depth = 0; *cp; cp++) {
1354                 if (*cp == '{')
1355                         bracket_depth++;
1356                 else if (bracket_depth && *cp == '}')
1357                         bracket_depth--;
1358                 else if (!bracket_depth && *cp == ':')
1359                         break;
1360         }
1361         if (*cp == ':') {
1362                 unsigned char tree_sha1[20];
1363                 int len = cp - name;
1364                 if (!get_sha1_1(name, len, tree_sha1, GET_SHA1_TREEISH)) {
1365                         const char *filename = cp+1;
1366                         char *new_filename = NULL;
1367
1368                         new_filename = resolve_relative_path(filename);
1369                         if (new_filename)
1370                                 filename = new_filename;
1371                         ret = get_tree_entry(tree_sha1, filename, sha1, &oc->mode);
1372                         if (ret && only_to_die) {
1373                                 diagnose_invalid_sha1_path(prefix, filename,
1374                                                            tree_sha1,
1375                                                            name, len);
1376                         }
1377                         hashcpy(oc->tree, tree_sha1);
1378                         strncpy(oc->path, filename,
1379                                 sizeof(oc->path));
1380                         oc->path[sizeof(oc->path)-1] = '\0';
1381
1382                         free(new_filename);
1383                         return ret;
1384                 } else {
1385                         if (only_to_die)
1386                                 die("Invalid object name '%.*s'.", len, name);
1387                 }
1388         }
1389         return ret;
1390 }
1391
1392 /*
1393  * Call this function when you know "name" given by the end user must
1394  * name an object but it doesn't; the function _may_ die with a better
1395  * diagnostic message than "no such object 'name'", e.g. "Path 'doc' does not
1396  * exist in 'HEAD'" when given "HEAD:doc", or it may return in which case
1397  * you have a chance to diagnose the error further.
1398  */
1399 void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
1400 {
1401         struct object_context oc;
1402         unsigned char sha1[20];
1403         get_sha1_with_context_1(name, GET_SHA1_ONLY_TO_DIE, prefix, sha1, &oc);
1404 }
1405
1406 int get_sha1_with_context(const char *str, unsigned flags, unsigned char *sha1, struct object_context *orc)
1407 {
1408         return get_sha1_with_context_1(str, flags, NULL, sha1, orc);
1409 }