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 static int interpret_nth_prior_checkout(const char *name, struct strbuf *buf);
 435
 436 static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 437 {
 438         static const char *warn_msg = "refname '%.*s' is ambiguous.";
 439         static const char *object_name_msg = N_(
 440         "Git normally never creates a ref that ends with 40 hex characters\n"
 441         "because it will be ignored when you just specify 40-hex. These refs\n"
 442         "may be created by mistake. For example,\n"
 443         "\n"
 444         "  git checkout -b $br $(git rev-parse ...)\n"
 445         "\n"
 446         "where \"$br\" is somehow empty and a 40-hex ref is created. Please\n"
 447         "examine these refs and maybe delete them. Turn this message off by\n"
 448         "running \"git config advice.object_name_warning false\"");
 449         unsigned char tmp_sha1[20];
 450         char *real_ref = NULL;
 451         int refs_found = 0;
 452         int at, reflog_len, nth_prior = 0;
 453
 454         if (len == 40 && !get_sha1_hex(str, sha1)) {
 455                 refs_found = dwim_ref(str, len, tmp_sha1, &real_ref);
 456                 if (refs_found > 0 && warn_ambiguous_refs) {
 457                         warning(warn_msg, len, str);
 458                         if (advice_object_name_warning)
 459                                 fprintf(stderr, "%s\n", _(object_name_msg));
 460                 }
 461                 free(real_ref);
 462                 return 0;
 463         }
 464
 465         /* basic@{time or number or -number} format to query ref-log */
 466         reflog_len = at = 0;
 467         if (len && str[len-1] == '}') {
 468                 for (at = len-4; at >= 0; at--) {
 469                         if (str[at] == '@' && str[at+1] == '{') {
 470                                 if (str[at+2] == '-') {
 471                                         if (at != 0)
 472                                                 /* @{-N} not at start */
 473                                                 return -1;
 474                                         nth_prior = 1;
 475                                         continue;
 476                                 }
 477                                 if (!upstream_mark(str + at, len - at)) {
 478                                         reflog_len = (len-1) - (at+2);
 479                                         len = at;
 480                                 }
 481                                 break;
 482                         }
 483                 }
 484         }
 485
 486         /* Accept only unambiguous ref paths. */
 487         if (len && ambiguous_path(str, len))
 488                 return -1;
 489
 490         if (nth_prior) {
 491                 struct strbuf buf = STRBUF_INIT;
 492                 int detached;
 493
 494                 if (interpret_nth_prior_checkout(str, &buf) > 0) {
 495                         detached = (buf.len == 40 && !get_sha1_hex(buf.buf, sha1));
 496                         strbuf_release(&buf);
 497                         if (detached)
 498                                 return 0;
 499                 }
 500         }
 501
 502         if (!len && reflog_len)
 503                 /* allow "@{...}" to mean the current branch reflog */
 504                 refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
 505         else if (reflog_len)
 506                 refs_found = dwim_log(str, len, sha1, &real_ref);
 507         else
 508                 refs_found = dwim_ref(str, len, sha1, &real_ref);
 509
 510         if (!refs_found)
 511                 return -1;
 512
 513         if (warn_ambiguous_refs &&
 514             (refs_found > 1 ||
 515              !get_short_sha1(str, len, tmp_sha1, GET_SHA1_QUIETLY)))
 516                 warning(warn_msg, len, str);
 517
 518         if (reflog_len) {
 519                 int nth, i;
 520                 unsigned long at_time;
 521                 unsigned long co_time;
 522                 int co_tz, co_cnt;
 523
 524                 /* Is it asking for N-th entry, or approxidate? */
 525                 for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 526                         char ch = str[at+2+i];
 527                         if ('0' <= ch && ch <= '9')
 528                                 nth = nth * 10 + ch - '0';
 529                         else
 530                                 nth = -1;
 531                 }
 532                 if (100000000 <= nth) {
 533                         at_time = nth;
 534                         nth = -1;
 535                 } else if (0 <= nth)
 536                         at_time = 0;
 537                 else {
 538                         int errors = 0;
 539                         char *tmp = xstrndup(str + at + 2, reflog_len);
 540                         at_time = approxidate_careful(tmp, &errors);
 541                         free(tmp);
 542                         if (errors)
 543                                 return -1;
 544                 }
 545                 if (read_ref_at(real_ref, at_time, nth, sha1, NULL,
 546                                 &co_time, &co_tz, &co_cnt)) {
 547                         if (!len) {
 548                                 if (!prefixcmp(real_ref, "refs/heads/")) {
 549                                         str = real_ref + 11;
 550                                         len = strlen(real_ref + 11);
 551                                 } else {
 552                                         /* detached HEAD */
 553                                         str = "HEAD";
 554                                         len = 4;
 555                                 }
 556                         }
 557                         if (at_time)
 558                                 warning("Log for '%.*s' only goes "
 559                                         "back to %s.", len, str,
 560                                         show_date(co_time, co_tz, DATE_RFC2822));
 561                         else {
 562                                 die("Log for '%.*s' only has %d entries.",
 563                                     len, str, co_cnt);
 564                         }
 565                 }
 566         }
 567
 568         free(real_ref);
 569         return 0;
 570 }
 571
 572 static int get_parent(const char *name, int len,
 573                       unsigned char *result, int idx)
 574 {
 575         unsigned char sha1[20];
 576         int ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 577         struct commit *commit;
 578         struct commit_list *p;
 579
 580         if (ret)
 581                 return ret;
 582         commit = lookup_commit_reference(sha1);
 583         if (!commit)
 584                 return -1;
 585         if (parse_commit(commit))
 586                 return -1;
 587         if (!idx) {
 588                 hashcpy(result, commit->object.sha1);
 589                 return 0;
 590         }
 591         p = commit->parents;
 592         while (p) {
 593                 if (!--idx) {
 594                         hashcpy(result, p->item->object.sha1);
 595                         return 0;
 596                 }
 597                 p = p->next;
 598         }
 599         return -1;
 600 }
 601
 602 static int get_nth_ancestor(const char *name, int len,
 603                             unsigned char *result, int generation)
 604 {
 605         unsigned char sha1[20];
 606         struct commit *commit;
 607         int ret;
 608
 609         ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 610         if (ret)
 611                 return ret;
 612         commit = lookup_commit_reference(sha1);
 613         if (!commit)
 614                 return -1;
 615
 616         while (generation--) {
 617                 if (parse_commit(commit) || !commit->parents)
 618                         return -1;
 619                 commit = commit->parents->item;
 620         }
 621         hashcpy(result, commit->object.sha1);
 622         return 0;
 623 }
 624
 625 struct object *peel_to_type(const char *name, int namelen,
 626                             struct object *o, enum object_type expected_type)
 627 {
 628         if (name && !namelen)
 629                 namelen = strlen(name);
 630         while (1) {
 631                 if (!o || (!o->parsed && !parse_object(o->sha1)))
 632                         return NULL;
 633                 if (expected_type == OBJ_ANY || o->type == expected_type)
 634                         return o;
 635                 if (o->type == OBJ_TAG)
 636                         o = ((struct tag*) o)->tagged;
 637                 else if (o->type == OBJ_COMMIT)
 638                         o = &(((struct commit *) o)->tree->object);
 639                 else {
 640                         if (name)
 641                                 error("%.*s: expected %s type, but the object "
 642                                       "dereferences to %s type",
 643                                       namelen, name, typename(expected_type),
 644                                       typename(o->type));
 645                         return NULL;
 646                 }
 647         }
 648 }
 649
 650 static int peel_onion(const char *name, int len, unsigned char *sha1)
 651 {
 652         unsigned char outer[20];
 653         const char *sp;
 654         unsigned int expected_type = 0;
 655         unsigned lookup_flags = 0;
 656         struct object *o;
 657
 658         /*
 659          * "ref^{type}" dereferences ref repeatedly until you cannot
 660          * dereference anymore, or you get an object of given type,
 661          * whichever comes first.  "ref^{}" means just dereference
 662          * tags until you get a non-tag.  "ref^0" is a shorthand for
 663          * "ref^{commit}".  "commit^{tree}" could be used to find the
 664          * top-level tree of the given commit.
 665          */
 666         if (len < 4 || name[len-1] != '}')
 667                 return -1;
 668
 669         for (sp = name + len - 1; name <= sp; sp--) {
 670                 int ch = *sp;
 671                 if (ch == '{' && name < sp && sp[-1] == '^')
 672                         break;
 673         }
 674         if (sp <= name)
 675                 return -1;
 676
 677         sp++; /* beginning of type name, or closing brace for empty */
 678         if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
 679                 expected_type = OBJ_COMMIT;
 680         else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
 681                 expected_type = OBJ_TREE;
 682         else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
 683                 expected_type = OBJ_BLOB;
 684         else if (!prefixcmp(sp, "object}"))
 685                 expected_type = OBJ_ANY;
 686         else if (sp[0] == '}')
 687                 expected_type = OBJ_NONE;
 688         else if (sp[0] == '/')
 689                 expected_type = OBJ_COMMIT;
 690         else
 691                 return -1;
 692
 693         if (expected_type == OBJ_COMMIT)
 694                 lookup_flags = GET_SHA1_COMMITTISH;
 695         else if (expected_type == OBJ_TREE)
 696                 lookup_flags = GET_SHA1_TREEISH;
 697
 698         if (get_sha1_1(name, sp - name - 2, outer, lookup_flags))
 699                 return -1;
 700
 701         o = parse_object(outer);
 702         if (!o)
 703                 return -1;
 704         if (!expected_type) {
 705                 o = deref_tag(o, name, sp - name - 2);
 706                 if (!o || (!o->parsed && !parse_object(o->sha1)))
 707                         return -1;
 708                 hashcpy(sha1, o->sha1);
 709                 return 0;
 710         }
 711
 712         /*
 713          * At this point, the syntax look correct, so
 714          * if we do not get the needed object, we should
 715          * barf.
 716          */
 717         o = peel_to_type(name, len, o, expected_type);
 718         if (!o)
 719                 return -1;
 720
 721         hashcpy(sha1, o->sha1);
 722         if (sp[0] == '/') {
 723                 /* "$commit^{/foo}" */
 724                 char *prefix;
 725                 int ret;
 726                 struct commit_list *list = NULL;
 727
 728                 /*
 729                  * $commit^{/}. Some regex implementation may reject.
 730                  * We don't need regex anyway. '' pattern always matches.
 731                  */
 732                 if (sp[1] == '}')
 733                         return 0;
 734
 735                 prefix = xstrndup(sp + 1, name + len - 1 - (sp + 1));
 736                 commit_list_insert((struct commit *)o, &list);
 737                 ret = get_sha1_oneline(prefix, sha1, list);
 738                 free(prefix);
 739                 return ret;
 740         }
 741         return 0;
 742 }
 743
 744 static int get_describe_name(const char *name, int len, unsigned char *sha1)
 745 {
 746         const char *cp;
 747         unsigned flags = GET_SHA1_QUIETLY | GET_SHA1_COMMIT;
 748
 749         for (cp = name + len - 1; name + 2 <= cp; cp--) {
 750                 char ch = *cp;
 751                 if (hexval(ch) & ~0377) {
 752                         /* We must be looking at g in "SOMETHING-g"
 753                          * for it to be describe output.
 754                          */
 755                         if (ch == 'g' && cp[-1] == '-') {
 756                                 cp++;
 757                                 len -= cp - name;
 758                                 return get_short_sha1(cp, len, sha1, flags);
 759                         }
 760                 }
 761         }
 762         return -1;
 763 }
 764
 765 static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags)
 766 {
 767         int ret, has_suffix;
 768         const char *cp;
 769
 770         /*
 771          * "name~3" is "name^^^", "name~" is "name~1", and "name^" is "name^1".
 772          */
 773         has_suffix = 0;
 774         for (cp = name + len - 1; name <= cp; cp--) {
 775                 int ch = *cp;
 776                 if ('0' <= ch && ch <= '9')
 777                         continue;
 778                 if (ch == '~' || ch == '^')
 779                         has_suffix = ch;
 780                 break;
 781         }
 782
 783         if (has_suffix) {
 784                 int num = 0;
 785                 int len1 = cp - name;
 786                 cp++;
 787                 while (cp < name + len)
 788                         num = num * 10 + *cp++ - '0';
 789                 if (!num && len1 == len - 1)
 790                         num = 1;
 791                 if (has_suffix == '^')
 792                         return get_parent(name, len1, sha1, num);
 793                 /* else if (has_suffix == '~') -- goes without saying */
 794                 return get_nth_ancestor(name, len1, sha1, num);
 795         }
 796
 797         ret = peel_onion(name, len, sha1);
 798         if (!ret)
 799                 return 0;
 800
 801         ret = get_sha1_basic(name, len, sha1);
 802         if (!ret)
 803                 return 0;
 804
 805         /* It could be describe output that is "SOMETHING-gXXXX" */
 806         ret = get_describe_name(name, len, sha1);
 807         if (!ret)
 808                 return 0;
 809
 810         return get_short_sha1(name, len, sha1, lookup_flags);
 811 }
 812
 813 /*
 814  * This interprets names like ':/Initial revision of "git"' by searching
 815  * through history and returning the first commit whose message starts
 816  * the given regular expression.
 817  *
 818  * For future extension, ':/!' is reserved. If you want to match a message
 819  * beginning with a '!', you have to repeat the exclamation mark.
 820  */
 821 #define ONELINE_SEEN (1u<<20)
 822
 823 static int handle_one_ref(const char *path,
 824                 const unsigned char *sha1, int flag, void *cb_data)
 825 {
 826         struct commit_list **list = cb_data;
 827         struct object *object = parse_object(sha1);
 828         if (!object)
 829                 return 0;
 830         if (object->type == OBJ_TAG) {
 831                 object = deref_tag(object, path, strlen(path));
 832                 if (!object)
 833                         return 0;
 834         }
 835         if (object->type != OBJ_COMMIT)
 836                 return 0;
 837         commit_list_insert_by_date((struct commit *)object, list);
 838         return 0;
 839 }
 840
 841 static int get_sha1_oneline(const char *prefix, unsigned char *sha1,
 842                             struct commit_list *list)
 843 {
 844         struct commit_list *backup = NULL, *l;
 845         int found = 0;
 846         regex_t regex;
 847
 848         if (prefix[0] == '!') {
 849                 if (prefix[1] != '!')
 850                         die ("Invalid search pattern: %s", prefix);
 851                 prefix++;
 852         }
 853
 854         if (regcomp(&regex, prefix, REG_EXTENDED))
 855                 die("Invalid search pattern: %s", prefix);
 856
 857         for (l = list; l; l = l->next) {
 858                 l->item->object.flags |= ONELINE_SEEN;
 859                 commit_list_insert(l->item, &backup);
 860         }
 861         while (list) {
 862                 char *p, *to_free = NULL;
 863                 struct commit *commit;
 864                 enum object_type type;
 865                 unsigned long size;
 866                 int matches;
 867
 868                 commit = pop_most_recent_commit(&list, ONELINE_SEEN);
 869                 if (!parse_object(commit->object.sha1))
 870                         continue;
 871                 if (commit->buffer)
 872                         p = commit->buffer;
 873                 else {
 874                         p = read_sha1_file(commit->object.sha1, &type, &size);
 875                         if (!p)
 876                                 continue;
 877                         to_free = p;
 878                 }
 879
 880                 p = strstr(p, "\n\n");
 881                 matches = p && !regexec(&regex, p + 2, 0, NULL, 0);
 882                 free(to_free);
 883
 884                 if (matches) {
 885                         hashcpy(sha1, commit->object.sha1);
 886                         found = 1;
 887                         break;
 888                 }
 889         }
 890         regfree(&regex);
 891         free_commit_list(list);
 892         for (l = backup; l; l = l->next)
 893                 clear_commit_marks(l->item, ONELINE_SEEN);
 894         free_commit_list(backup);
 895         return found ? 0 : -1;
 896 }
 897
 898 struct grab_nth_branch_switch_cbdata {
 899         int remaining;
 900         struct strbuf buf;
 901 };
 902
 903 static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
 904                                   const char *email, unsigned long timestamp, int tz,
 905                                   const char *message, void *cb_data)
 906 {
 907         struct grab_nth_branch_switch_cbdata *cb = cb_data;
 908         const char *match = NULL, *target = NULL;
 909         size_t len;
 910
 911         if (!prefixcmp(message, "checkout: moving from ")) {
 912                 match = message + strlen("checkout: moving from ");
 913                 target = strstr(match, " to ");
 914         }
 915
 916         if (!match || !target)
 917                 return 0;
 918         if (--(cb->remaining) == 0) {
 919                 len = target - match;
 920                 strbuf_reset(&cb->buf);
 921                 strbuf_add(&cb->buf, match, len);
 922                 return 1; /* we are done */
 923         }
 924         return 0;
 925 }
 926
 927 /*
 928  * Parse @{-N} syntax, return the number of characters parsed
 929  * if successful; otherwise signal an error with negative value.
 930  */
 931 static int interpret_nth_prior_checkout(const char *name, struct strbuf *buf)
 932 {
 933         long nth;
 934         int retval;
 935         struct grab_nth_branch_switch_cbdata cb;
 936         const char *brace;
 937         char *num_end;
 938
 939         if (name[0] != '@' || name[1] != '{' || name[2] != '-')
 940                 return -1;
 941         brace = strchr(name, '}');
 942         if (!brace)
 943                 return -1;
 944         nth = strtol(name + 3, &num_end, 10);
 945         if (num_end != brace)
 946                 return -1;
 947         if (nth <= 0)
 948                 return -1;
 949         cb.remaining = nth;
 950         strbuf_init(&cb.buf, 20);
 951
 952         retval = 0;
 953         if (0 < for_each_reflog_ent_reverse("HEAD", grab_nth_branch_switch, &cb)) {
 954                 strbuf_reset(buf);
 955                 strbuf_add(buf, cb.buf.buf, cb.buf.len);
 956                 retval = brace - name + 1;
 957         }
 958
 959         strbuf_release(&cb.buf);
 960         return retval;
 961 }
 962
 963 int get_sha1_mb(const char *name, unsigned char *sha1)
 964 {
 965         struct commit *one, *two;
 966         struct commit_list *mbs;
 967         unsigned char sha1_tmp[20];
 968         const char *dots;
 969         int st;
 970
 971         dots = strstr(name, "...");
 972         if (!dots)
 973                 return get_sha1(name, sha1);
 974         if (dots == name)
 975                 st = get_sha1("HEAD", sha1_tmp);
 976         else {
 977                 struct strbuf sb;
 978                 strbuf_init(&sb, dots - name);
 979                 strbuf_add(&sb, name, dots - name);
 980                 st = get_sha1_committish(sb.buf, sha1_tmp);
 981                 strbuf_release(&sb);
 982         }
 983         if (st)
 984                 return st;
 985         one = lookup_commit_reference_gently(sha1_tmp, 0);
 986         if (!one)
 987                 return -1;
 988
 989         if (get_sha1_committish(dots[3] ? (dots + 3) : "HEAD", sha1_tmp))
 990                 return -1;
 991         two = lookup_commit_reference_gently(sha1_tmp, 0);
 992         if (!two)
 993                 return -1;
 994         mbs = get_merge_bases(one, two, 1);
 995         if (!mbs || mbs->next)
 996                 st = -1;
 997         else {
 998                 st = 0;
 999                 hashcpy(sha1, mbs->item->object.sha1);
1000         }
1001         free_commit_list(mbs);
1002         return st;
1003 }
1004
1005 /* parse @something syntax, when 'something' is not {.*} */
1006 static int interpret_empty_at(const char *name, int namelen, int len, struct strbuf *buf)
1007 {
1008         if (len || name[1] == '{')
1009                 return -1;
1010
1011         strbuf_reset(buf);
1012         strbuf_add(buf, "HEAD", 4);
1013         return 1;
1014 }
1015
1016 static int reinterpret(const char *name, int namelen, int len, struct strbuf *buf)
1017 {
1018         /* we have extra data, which might need further processing */
1019         struct strbuf tmp = STRBUF_INIT;
1020         int used = buf->len;
1021         int ret;
1022
1023         strbuf_add(buf, name + len, namelen - len);
1024         ret = interpret_branch_name(buf->buf, &tmp);
1025         /* that data was not interpreted, remove our cruft */
1026         if (ret < 0) {
1027                 strbuf_setlen(buf, used);
1028                 return len;
1029         }
1030         strbuf_reset(buf);
1031         strbuf_addbuf(buf, &tmp);
1032         strbuf_release(&tmp);
1033         /* tweak for size of {-N} versus expanded ref name */
1034         return ret - used + len;
1035 }
1036
1037 /*
1038  * This reads short-hand syntax that not only evaluates to a commit
1039  * object name, but also can act as if the end user spelled the name
1040  * of the branch from the command line.
1041  *
1042  * - "@{-N}" finds the name of the Nth previous branch we were on, and
1043  *   places the name of the branch in the given buf and returns the
1044  *   number of characters parsed if successful.
1045  *
1046  * - "<branch>@{upstream}" finds the name of the other ref that
1047  *   <branch> is configured to merge with (missing <branch> defaults
1048  *   to the current branch), and places the name of the branch in the
1049  *   given buf and returns the number of characters parsed if
1050  *   successful.
1051  *
1052  * If the input is not of the accepted format, it returns a negative
1053  * number to signal an error.
1054  *
1055  * If the input was ok but there are not N branch switches in the
1056  * reflog, it returns 0.
1057  */
1058 int interpret_branch_name(const char *name, struct strbuf *buf)
1059 {
1060         char *cp;
1061         struct branch *upstream;
1062         int namelen = strlen(name);
1063         int len = interpret_nth_prior_checkout(name, buf);
1064         int tmp_len;
1065
1066         if (!len) {
1067                 return len; /* syntax Ok, not enough switches */
1068         } else if (len > 0) {
1069                 if (len == namelen)
1070                         return len; /* consumed all */
1071                 else
1072                         return reinterpret(name, namelen, len, buf);
1073         }
1074
1075         cp = strchr(name, '@');
1076         if (!cp)
1077                 return -1;
1078
1079         len = interpret_empty_at(name, namelen, cp - name, buf);
1080         if (len > 0)
1081                 return reinterpret(name, namelen, len, buf);
1082
1083         tmp_len = upstream_mark(cp, namelen - (cp - name));
1084         if (!tmp_len)
1085                 return -1;
1086
1087         len = cp + tmp_len - name;
1088         cp = xstrndup(name, cp - name);
1089         upstream = branch_get(*cp ? cp : NULL);
1090         /*
1091          * Upstream can be NULL only if cp refers to HEAD and HEAD
1092          * points to something different than a branch.
1093          */
1094         if (!upstream)
1095                 die(_("HEAD does not point to a branch"));
1096         if (!upstream->merge || !upstream->merge[0]->dst) {
1097                 if (!ref_exists(upstream->refname))
1098                         die(_("No such branch: '%s'"), cp);
1099                 if (!upstream->merge) {
1100                         die(_("No upstream configured for branch '%s'"),
1101                                 upstream->name);
1102                 }
1103                 die(
1104                         _("Upstream branch '%s' not stored as a remote-tracking branch"),
1105                         upstream->merge[0]->src);
1106         }
1107         free(cp);
1108         cp = shorten_unambiguous_ref(upstream->merge[0]->dst, 0);
1109         strbuf_reset(buf);
1110         strbuf_addstr(buf, cp);
1111         free(cp);
1112         return len;
1113 }
1114
1115 int strbuf_branchname(struct strbuf *sb, const char *name)
1116 {
1117         int len = strlen(name);
1118         int used = interpret_branch_name(name, sb);
1119
1120         if (used == len)
1121                 return 0;
1122         if (used < 0)
1123                 used = 0;
1124         strbuf_add(sb, name + used, len - used);
1125         return len;
1126 }
1127
1128 int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
1129 {
1130         strbuf_branchname(sb, name);
1131         if (name[0] == '-')
1132                 return -1;
1133         strbuf_splice(sb, 0, 0, "refs/heads/", 11);
1134         return check_refname_format(sb->buf, 0);
1135 }
1136
1137 /*
1138  * This is like "get_sha1_basic()", except it allows "sha1 expressions",
1139  * notably "xyz^" for "parent of xyz"
1140  */
1141 int get_sha1(const char *name, unsigned char *sha1)
1142 {
1143         struct object_context unused;
1144         return get_sha1_with_context(name, 0, sha1, &unused);
1145 }
1146
1147 /*
1148  * Many callers know that the user meant to name a committish by
1149  * syntactical positions where the object name appears.  Calling this
1150  * function allows the machinery to disambiguate shorter-than-unique
1151  * abbreviated object names between committish and others.
1152  *
1153  * Note that this does NOT error out when the named object is not a
1154  * committish. It is merely to give a hint to the disambiguation
1155  * machinery.
1156  */
1157 int get_sha1_committish(const char *name, unsigned char *sha1)
1158 {
1159         struct object_context unused;
1160         return get_sha1_with_context(name, GET_SHA1_COMMITTISH,
1161                                      sha1, &unused);
1162 }
1163
1164 int get_sha1_treeish(const char *name, unsigned char *sha1)
1165 {
1166         struct object_context unused;
1167         return get_sha1_with_context(name, GET_SHA1_TREEISH,
1168                                      sha1, &unused);
1169 }
1170
1171 int get_sha1_commit(const char *name, unsigned char *sha1)
1172 {
1173         struct object_context unused;
1174         return get_sha1_with_context(name, GET_SHA1_COMMIT,
1175                                      sha1, &unused);
1176 }
1177
1178 int get_sha1_tree(const char *name, unsigned char *sha1)
1179 {
1180         struct object_context unused;
1181         return get_sha1_with_context(name, GET_SHA1_TREE,
1182                                      sha1, &unused);
1183 }
1184
1185 int get_sha1_blob(const char *name, unsigned char *sha1)
1186 {
1187         struct object_context unused;
1188         return get_sha1_with_context(name, GET_SHA1_BLOB,
1189                                      sha1, &unused);
1190 }
1191
1192 /* Must be called only when object_name:filename doesn't exist. */
1193 static void diagnose_invalid_sha1_path(const char *prefix,
1194                                        const char *filename,
1195                                        const unsigned char *tree_sha1,
1196                                        const char *object_name,
1197                                        int object_name_len)
1198 {
1199         struct stat st;
1200         unsigned char sha1[20];
1201         unsigned mode;
1202
1203         if (!prefix)
1204                 prefix = "";
1205
1206         if (!lstat(filename, &st))
1207                 die("Path '%s' exists on disk, but not in '%.*s'.",
1208                     filename, object_name_len, object_name);
1209         if (errno == ENOENT || errno == ENOTDIR) {
1210                 char *fullname = xmalloc(strlen(filename)
1211                                              + strlen(prefix) + 1);
1212                 strcpy(fullname, prefix);
1213                 strcat(fullname, filename);
1214
1215                 if (!get_tree_entry(tree_sha1, fullname,
1216                                     sha1, &mode)) {
1217                         die("Path '%s' exists, but not '%s'.\n"
1218                             "Did you mean '%.*s:%s' aka '%.*s:./%s'?",
1219                             fullname,
1220                             filename,
1221                             object_name_len, object_name,
1222                             fullname,
1223                             object_name_len, object_name,
1224                             filename);
1225                 }
1226                 die("Path '%s' does not exist in '%.*s'",
1227                     filename, object_name_len, object_name);
1228         }
1229 }
1230
1231 /* Must be called only when :stage:filename doesn't exist. */
1232 static void diagnose_invalid_index_path(int stage,
1233                                         const char *prefix,
1234                                         const char *filename)
1235 {
1236         struct stat st;
1237         struct cache_entry *ce;
1238         int pos;
1239         unsigned namelen = strlen(filename);
1240         unsigned fullnamelen;
1241         char *fullname;
1242
1243         if (!prefix)
1244                 prefix = "";
1245
1246         /* Wrong stage number? */
1247         pos = cache_name_pos(filename, namelen);
1248         if (pos < 0)
1249                 pos = -pos - 1;
1250         if (pos < active_nr) {
1251                 ce = active_cache[pos];
1252                 if (ce_namelen(ce) == namelen &&
1253                     !memcmp(ce->name, filename, namelen))
1254                         die("Path '%s' is in the index, but not at stage %d.\n"
1255                             "Did you mean ':%d:%s'?",
1256                             filename, stage,
1257                             ce_stage(ce), filename);
1258         }
1259
1260         /* Confusion between relative and absolute filenames? */
1261         fullnamelen = namelen + strlen(prefix);
1262         fullname = xmalloc(fullnamelen + 1);
1263         strcpy(fullname, prefix);
1264         strcat(fullname, filename);
1265         pos = cache_name_pos(fullname, fullnamelen);
1266         if (pos < 0)
1267                 pos = -pos - 1;
1268         if (pos < active_nr) {
1269                 ce = active_cache[pos];
1270                 if (ce_namelen(ce) == fullnamelen &&
1271                     !memcmp(ce->name, fullname, fullnamelen))
1272                         die("Path '%s' is in the index, but not '%s'.\n"
1273                             "Did you mean ':%d:%s' aka ':%d:./%s'?",
1274                             fullname, filename,
1275                             ce_stage(ce), fullname,
1276                             ce_stage(ce), filename);
1277         }
1278
1279         if (!lstat(filename, &st))
1280                 die("Path '%s' exists on disk, but not in the index.", filename);
1281         if (errno == ENOENT || errno == ENOTDIR)
1282                 die("Path '%s' does not exist (neither on disk nor in the index).",
1283                     filename);
1284
1285         free(fullname);
1286 }
1287
1288
1289 static char *resolve_relative_path(const char *rel)
1290 {
1291         if (prefixcmp(rel, "./") && prefixcmp(rel, "../"))
1292                 return NULL;
1293
1294         if (!startup_info)
1295                 die("BUG: startup_info struct is not initialized.");
1296
1297         if (!is_inside_work_tree())
1298                 die("relative path syntax can't be used outside working tree.");
1299
1300         /* die() inside prefix_path() if resolved path is outside worktree */
1301         return prefix_path(startup_info->prefix,
1302                            startup_info->prefix ? strlen(startup_info->prefix) : 0,
1303                            rel);
1304 }
1305
1306 static int get_sha1_with_context_1(const char *name,
1307                                    unsigned flags,
1308                                    const char *prefix,
1309                                    unsigned char *sha1,
1310                                    struct object_context *oc)
1311 {
1312         int ret, bracket_depth;
1313         int namelen = strlen(name);
1314         const char *cp;
1315         int only_to_die = flags & GET_SHA1_ONLY_TO_DIE;
1316
1317         memset(oc, 0, sizeof(*oc));
1318         oc->mode = S_IFINVALID;
1319         ret = get_sha1_1(name, namelen, sha1, flags);
1320         if (!ret)
1321                 return ret;
1322         /*
1323          * sha1:path --> object name of path in ent sha1
1324          * :path -> object name of absolute path in index
1325          * :./path -> object name of path relative to cwd in index
1326          * :[0-3]:path -> object name of path in index at stage
1327          * :/foo -> recent commit matching foo
1328          */
1329         if (name[0] == ':') {
1330                 int stage = 0;
1331                 struct cache_entry *ce;
1332                 char *new_path = NULL;
1333                 int pos;
1334                 if (!only_to_die && namelen > 2 && name[1] == '/') {
1335                         struct commit_list *list = NULL;
1336                         for_each_ref(handle_one_ref, &list);
1337                         return get_sha1_oneline(name + 2, sha1, list);
1338                 }
1339                 if (namelen < 3 ||
1340                     name[2] != ':' ||
1341                     name[1] < '0' || '3' < name[1])
1342                         cp = name + 1;
1343                 else {
1344                         stage = name[1] - '0';
1345                         cp = name + 3;
1346                 }
1347                 new_path = resolve_relative_path(cp);
1348                 if (!new_path) {
1349                         namelen = namelen - (cp - name);
1350                 } else {
1351                         cp = new_path;
1352                         namelen = strlen(cp);
1353                 }
1354
1355                 strncpy(oc->path, cp,
1356                         sizeof(oc->path));
1357                 oc->path[sizeof(oc->path)-1] = '\0';
1358
1359                 if (!active_cache)
1360                         read_cache();
1361                 pos = cache_name_pos(cp, namelen);
1362                 if (pos < 0)
1363                         pos = -pos - 1;
1364                 while (pos < active_nr) {
1365                         ce = active_cache[pos];
1366                         if (ce_namelen(ce) != namelen ||
1367                             memcmp(ce->name, cp, namelen))
1368                                 break;
1369                         if (ce_stage(ce) == stage) {
1370                                 hashcpy(sha1, ce->sha1);
1371                                 oc->mode = ce->ce_mode;
1372                                 free(new_path);
1373                                 return 0;
1374                         }
1375                         pos++;
1376                 }
1377                 if (only_to_die && name[1] && name[1] != '/')
1378                         diagnose_invalid_index_path(stage, prefix, cp);
1379                 free(new_path);
1380                 return -1;
1381         }
1382         for (cp = name, bracket_depth = 0; *cp; cp++) {
1383                 if (*cp == '{')
1384                         bracket_depth++;
1385                 else if (bracket_depth && *cp == '}')
1386                         bracket_depth--;
1387                 else if (!bracket_depth && *cp == ':')
1388                         break;
1389         }
1390         if (*cp == ':') {
1391                 unsigned char tree_sha1[20];
1392                 int len = cp - name;
1393                 if (!get_sha1_1(name, len, tree_sha1, GET_SHA1_TREEISH)) {
1394                         const char *filename = cp+1;
1395                         char *new_filename = NULL;
1396
1397                         new_filename = resolve_relative_path(filename);
1398                         if (new_filename)
1399                                 filename = new_filename;
1400                         ret = get_tree_entry(tree_sha1, filename, sha1, &oc->mode);
1401                         if (ret && only_to_die) {
1402                                 diagnose_invalid_sha1_path(prefix, filename,
1403                                                            tree_sha1,
1404                                                            name, len);
1405                         }
1406                         hashcpy(oc->tree, tree_sha1);
1407                         strncpy(oc->path, filename,
1408                                 sizeof(oc->path));
1409                         oc->path[sizeof(oc->path)-1] = '\0';
1410
1411                         free(new_filename);
1412                         return ret;
1413                 } else {
1414                         if (only_to_die)
1415                                 die("Invalid object name '%.*s'.", len, name);
1416                 }
1417         }
1418         return ret;
1419 }
1420
1421 /*
1422  * Call this function when you know "name" given by the end user must
1423  * name an object but it doesn't; the function _may_ die with a better
1424  * diagnostic message than "no such object 'name'", e.g. "Path 'doc' does not
1425  * exist in 'HEAD'" when given "HEAD:doc", or it may return in which case
1426  * you have a chance to diagnose the error further.
1427  */
1428 void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
1429 {
1430         struct object_context oc;
1431         unsigned char sha1[20];
1432         get_sha1_with_context_1(name, GET_SHA1_ONLY_TO_DIE, prefix, sha1, &oc);
1433 }
1434
1435 int get_sha1_with_context(const char *str, unsigned flags, unsigned char *sha1, struct object_context *orc)
1436 {
1437         return get_sha1_with_context_1(str, flags, NULL, sha1, orc);
1438 }