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 satisfy 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(parse_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 int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
 347 {
 348         char hex_pfx[40];
 349         unsigned char bin_pfx[20];
 350         struct disambiguate_state ds;
 351         int len = strlen(prefix);
 352
 353         if (len < MINIMUM_ABBREV || len > 40)
 354                 return -1;
 355         if (prepare_prefixes(prefix, len, bin_pfx, hex_pfx) < 0)
 356                 return -1;
 357
 358         prepare_alt_odb();
 359
 360         memset(&ds, 0, sizeof(ds));
 361         ds.always_call_fn = 1;
 362         ds.cb_data = cb_data;
 363         ds.fn = fn;
 364
 365         find_short_object_filename(len, hex_pfx, &ds);
 366         find_short_packed_object(len, bin_pfx, &ds);
 367         return ds.ambiguous;
 368 }
 369
 370 const char *find_unique_abbrev(const unsigned char *sha1, int len)
 371 {
 372         int status, exists;
 373         static char hex[41];
 374
 375         memcpy(hex, sha1_to_hex(sha1), 40);
 376         if (len == 40 || !len)
 377                 return hex;
 378         exists = has_sha1_file(sha1);
 379         while (len < 40) {
 380                 unsigned char sha1_ret[20];
 381                 status = get_short_sha1(hex, len, sha1_ret, GET_SHA1_QUIETLY);
 382                 if (exists
 383                     ? !status
 384                     : status == SHORT_NAME_NOT_FOUND) {
 385                         hex[len] = 0;
 386                         return hex;
 387                 }
 388                 len++;
 389         }
 390         return hex;
 391 }
 392
 393 static int ambiguous_path(const char *path, int len)
 394 {
 395         int slash = 1;
 396         int cnt;
 397
 398         for (cnt = 0; cnt < len; cnt++) {
 399                 switch (*path++) {
 400                 case '\0':
 401                         break;
 402                 case '/':
 403                         if (slash)
 404                                 break;
 405                         slash = 1;
 406                         continue;
 407                 case '.':
 408                         continue;
 409                 default:
 410                         slash = 0;
 411                         continue;
 412                 }
 413                 break;
 414         }
 415         return slash;
 416 }
 417
 418 static inline int upstream_mark(const char *string, int len)
 419 {
 420         const char *suffix[] = { "@{upstream}", "@{u}" };
 421         int i;
 422
 423         for (i = 0; i < ARRAY_SIZE(suffix); i++) {
 424                 int suffix_len = strlen(suffix[i]);
 425                 if (suffix_len <= len
 426                     && !memcmp(string, suffix[i], suffix_len))
 427                         return suffix_len;
 428         }
 429         return 0;
 430 }
 431
 432 static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags);
 433 static int interpret_nth_prior_checkout(const char *name, int namelen, struct strbuf *buf);
 434
 435 static int get_sha1_basic(const char *str, int len, unsigned char *sha1,
 436                           unsigned int flags)
 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.objectNameWarning 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                 if (warn_ambiguous_refs && warn_on_object_refname_ambiguity) {
 456                         refs_found = dwim_ref(str, len, tmp_sha1, &real_ref);
 457                         if (refs_found > 0) {
 458                                 warning(warn_msg, len, str);
 459                                 if (advice_object_name_warning)
 460                                         fprintf(stderr, "%s\n", _(object_name_msg));
 461                         }
 462                         free(real_ref);
 463                 }
 464                 return 0;
 465         }
 466
 467         /* basic@{time or number or -number} format to query ref-log */
 468         reflog_len = at = 0;
 469         if (len && str[len-1] == '}') {
 470                 for (at = len-4; at >= 0; at--) {
 471                         if (str[at] == '@' && str[at+1] == '{') {
 472                                 if (str[at+2] == '-') {
 473                                         if (at != 0)
 474                                                 /* @{-N} not at start */
 475                                                 return -1;
 476                                         nth_prior = 1;
 477                                         continue;
 478                                 }
 479                                 if (!upstream_mark(str + at, len - at)) {
 480                                         reflog_len = (len-1) - (at+2);
 481                                         len = at;
 482                                 }
 483                                 break;
 484                         }
 485                 }
 486         }
 487
 488         /* Accept only unambiguous ref paths. */
 489         if (len && ambiguous_path(str, len))
 490                 return -1;
 491
 492         if (nth_prior) {
 493                 struct strbuf buf = STRBUF_INIT;
 494                 int detached;
 495
 496                 if (interpret_nth_prior_checkout(str, len, &buf) > 0) {
 497                         detached = (buf.len == 40 && !get_sha1_hex(buf.buf, sha1));
 498                         strbuf_release(&buf);
 499                         if (detached)
 500                                 return 0;
 501                 }
 502         }
 503
 504         if (!len && reflog_len)
 505                 /* allow "@{...}" to mean the current branch reflog */
 506                 refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
 507         else if (reflog_len)
 508                 refs_found = dwim_log(str, len, sha1, &real_ref);
 509         else
 510                 refs_found = dwim_ref(str, len, sha1, &real_ref);
 511
 512         if (!refs_found)
 513                 return -1;
 514
 515         if (warn_ambiguous_refs && !(flags & GET_SHA1_QUIETLY) &&
 516             (refs_found > 1 ||
 517              !get_short_sha1(str, len, tmp_sha1, GET_SHA1_QUIETLY)))
 518                 warning(warn_msg, len, str);
 519
 520         if (reflog_len) {
 521                 int nth, i;
 522                 unsigned long at_time;
 523                 unsigned long co_time;
 524                 int co_tz, co_cnt;
 525
 526                 /* Is it asking for N-th entry, or approxidate? */
 527                 for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 528                         char ch = str[at+2+i];
 529                         if ('0' <= ch && ch <= '9')
 530                                 nth = nth * 10 + ch - '0';
 531                         else
 532                                 nth = -1;
 533                 }
 534                 if (100000000 <= nth) {
 535                         at_time = nth;
 536                         nth = -1;
 537                 } else if (0 <= nth)
 538                         at_time = 0;
 539                 else {
 540                         int errors = 0;
 541                         char *tmp = xstrndup(str + at + 2, reflog_len);
 542                         at_time = approxidate_careful(tmp, &errors);
 543                         free(tmp);
 544                         if (errors) {
 545                                 free(real_ref);
 546                                 return -1;
 547                         }
 548                 }
 549                 if (read_ref_at(real_ref, flags, at_time, nth, sha1, NULL,
 550                                 &co_time, &co_tz, &co_cnt)) {
 551                         if (!len) {
 552                                 if (starts_with(real_ref, "refs/heads/")) {
 553                                         str = real_ref + 11;
 554                                         len = strlen(real_ref + 11);
 555                                 } else {
 556                                         /* detached HEAD */
 557                                         str = "HEAD";
 558                                         len = 4;
 559                                 }
 560                         }
 561                         if (at_time) {
 562                                 if (!(flags & GET_SHA1_QUIETLY)) {
 563                                         warning("Log for '%.*s' only goes "
 564                                                 "back to %s.", len, str,
 565                                                 show_date(co_time, co_tz, DATE_RFC2822));
 566                                 }
 567                         } else {
 568                                 if (flags & GET_SHA1_QUIETLY) {
 569                                         exit(128);
 570                                 }
 571                                 die("Log for '%.*s' only has %d entries.",
 572                                     len, str, co_cnt);
 573                         }
 574                 }
 575         }
 576
 577         free(real_ref);
 578         return 0;
 579 }
 580
 581 static int get_parent(const char *name, int len,
 582                       unsigned char *result, int idx)
 583 {
 584         unsigned char sha1[20];
 585         int ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 586         struct commit *commit;
 587         struct commit_list *p;
 588
 589         if (ret)
 590                 return ret;
 591         commit = lookup_commit_reference(sha1);
 592         if (parse_commit(commit))
 593                 return -1;
 594         if (!idx) {
 595                 hashcpy(result, commit->object.sha1);
 596                 return 0;
 597         }
 598         p = commit->parents;
 599         while (p) {
 600                 if (!--idx) {
 601                         hashcpy(result, p->item->object.sha1);
 602                         return 0;
 603                 }
 604                 p = p->next;
 605         }
 606         return -1;
 607 }
 608
 609 static int get_nth_ancestor(const char *name, int len,
 610                             unsigned char *result, int generation)
 611 {
 612         unsigned char sha1[20];
 613         struct commit *commit;
 614         int ret;
 615
 616         ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 617         if (ret)
 618                 return ret;
 619         commit = lookup_commit_reference(sha1);
 620         if (!commit)
 621                 return -1;
 622
 623         while (generation--) {
 624                 if (parse_commit(commit) || !commit->parents)
 625                         return -1;
 626                 commit = commit->parents->item;
 627         }
 628         hashcpy(result, commit->object.sha1);
 629         return 0;
 630 }
 631
 632 struct object *peel_to_type(const char *name, int namelen,
 633                             struct object *o, enum object_type expected_type)
 634 {
 635         if (name && !namelen)
 636                 namelen = strlen(name);
 637         while (1) {
 638                 if (!o || (!o->parsed && !parse_object(o->sha1)))
 639                         return NULL;
 640                 if (expected_type == OBJ_ANY || o->type == expected_type)
 641                         return o;
 642                 if (o->type == OBJ_TAG)
 643                         o = ((struct tag*) o)->tagged;
 644                 else if (o->type == OBJ_COMMIT)
 645                         o = &(((struct commit *) o)->tree->object);
 646                 else {
 647                         if (name)
 648                                 error("%.*s: expected %s type, but the object "
 649                                       "dereferences to %s type",
 650                                       namelen, name, typename(expected_type),
 651                                       typename(o->type));
 652                         return NULL;
 653                 }
 654         }
 655 }
 656
 657 static int peel_onion(const char *name, int len, unsigned char *sha1)
 658 {
 659         unsigned char outer[20];
 660         const char *sp;
 661         unsigned int expected_type = 0;
 662         unsigned lookup_flags = 0;
 663         struct object *o;
 664
 665         /*
 666          * "ref^{type}" dereferences ref repeatedly until you cannot
 667          * dereference anymore, or you get an object of given type,
 668          * whichever comes first.  "ref^{}" means just dereference
 669          * tags until you get a non-tag.  "ref^0" is a shorthand for
 670          * "ref^{commit}".  "commit^{tree}" could be used to find the
 671          * top-level tree of the given commit.
 672          */
 673         if (len < 4 || name[len-1] != '}')
 674                 return -1;
 675
 676         for (sp = name + len - 1; name <= sp; sp--) {
 677                 int ch = *sp;
 678                 if (ch == '{' && name < sp && sp[-1] == '^')
 679                         break;
 680         }
 681         if (sp <= name)
 682                 return -1;
 683
 684         sp++; /* beginning of type name, or closing brace for empty */
 685         if (starts_with(sp, "commit}"))
 686                 expected_type = OBJ_COMMIT;
 687         else if (starts_with(sp, "tag}"))
 688                 expected_type = OBJ_TAG;
 689         else if (starts_with(sp, "tree}"))
 690                 expected_type = OBJ_TREE;
 691         else if (starts_with(sp, "blob}"))
 692                 expected_type = OBJ_BLOB;
 693         else if (starts_with(sp, "object}"))
 694                 expected_type = OBJ_ANY;
 695         else if (sp[0] == '}')
 696                 expected_type = OBJ_NONE;
 697         else if (sp[0] == '/')
 698                 expected_type = OBJ_COMMIT;
 699         else
 700                 return -1;
 701
 702         if (expected_type == OBJ_COMMIT)
 703                 lookup_flags = GET_SHA1_COMMITTISH;
 704         else if (expected_type == OBJ_TREE)
 705                 lookup_flags = GET_SHA1_TREEISH;
 706
 707         if (get_sha1_1(name, sp - name - 2, outer, lookup_flags))
 708                 return -1;
 709
 710         o = parse_object(outer);
 711         if (!o)
 712                 return -1;
 713         if (!expected_type) {
 714                 o = deref_tag(o, name, sp - name - 2);
 715                 if (!o || (!o->parsed && !parse_object(o->sha1)))
 716                         return -1;
 717                 hashcpy(sha1, o->sha1);
 718                 return 0;
 719         }
 720
 721         /*
 722          * At this point, the syntax look correct, so
 723          * if we do not get the needed object, we should
 724          * barf.
 725          */
 726         o = peel_to_type(name, len, o, expected_type);
 727         if (!o)
 728                 return -1;
 729
 730         hashcpy(sha1, o->sha1);
 731         if (sp[0] == '/') {
 732                 /* "$commit^{/foo}" */
 733                 char *prefix;
 734                 int ret;
 735                 struct commit_list *list = NULL;
 736
 737                 /*
 738                  * $commit^{/}. Some regex implementation may reject.
 739                  * We don't need regex anyway. '' pattern always matches.
 740                  */
 741                 if (sp[1] == '}')
 742                         return 0;
 743
 744                 prefix = xstrndup(sp + 1, name + len - 1 - (sp + 1));
 745                 commit_list_insert((struct commit *)o, &list);
 746                 ret = get_sha1_oneline(prefix, sha1, list);
 747                 free(prefix);
 748                 return ret;
 749         }
 750         return 0;
 751 }
 752
 753 static int get_describe_name(const char *name, int len, unsigned char *sha1)
 754 {
 755         const char *cp;
 756         unsigned flags = GET_SHA1_QUIETLY | GET_SHA1_COMMIT;
 757
 758         for (cp = name + len - 1; name + 2 <= cp; cp--) {
 759                 char ch = *cp;
 760                 if (hexval(ch) & ~0377) {
 761                         /* We must be looking at g in "SOMETHING-g"
 762                          * for it to be describe output.
 763                          */
 764                         if (ch == 'g' && cp[-1] == '-') {
 765                                 cp++;
 766                                 len -= cp - name;
 767                                 return get_short_sha1(cp, len, sha1, flags);
 768                         }
 769                 }
 770         }
 771         return -1;
 772 }
 773
 774 static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags)
 775 {
 776         int ret, has_suffix;
 777         const char *cp;
 778
 779         /*
 780          * "name~3" is "name^^^", "name~" is "name~1", and "name^" is "name^1".
 781          */
 782         has_suffix = 0;
 783         for (cp = name + len - 1; name <= cp; cp--) {
 784                 int ch = *cp;
 785                 if ('0' <= ch && ch <= '9')
 786                         continue;
 787                 if (ch == '~' || ch == '^')
 788                         has_suffix = ch;
 789                 break;
 790         }
 791
 792         if (has_suffix) {
 793                 int num = 0;
 794                 int len1 = cp - name;
 795                 cp++;
 796                 while (cp < name + len)
 797                         num = num * 10 + *cp++ - '0';
 798                 if (!num && len1 == len - 1)
 799                         num = 1;
 800                 if (has_suffix == '^')
 801                         return get_parent(name, len1, sha1, num);
 802                 /* else if (has_suffix == '~') -- goes without saying */
 803                 return get_nth_ancestor(name, len1, sha1, num);
 804         }
 805
 806         ret = peel_onion(name, len, sha1);
 807         if (!ret)
 808                 return 0;
 809
 810         ret = get_sha1_basic(name, len, sha1, lookup_flags);
 811         if (!ret)
 812                 return 0;
 813
 814         /* It could be describe output that is "SOMETHING-gXXXX" */
 815         ret = get_describe_name(name, len, sha1);
 816         if (!ret)
 817                 return 0;
 818
 819         return get_short_sha1(name, len, sha1, lookup_flags);
 820 }
 821
 822 /*
 823  * This interprets names like ':/Initial revision of "git"' by searching
 824  * through history and returning the first commit whose message starts
 825  * the given regular expression.
 826  *
 827  * For future extension, ':/!' is reserved. If you want to match a message
 828  * beginning with a '!', you have to repeat the exclamation mark.
 829  */
 830
 831 /* Remember to update object flag allocation in object.h */
 832 #define ONELINE_SEEN (1u<<20)
 833
 834 static int handle_one_ref(const char *path,
 835                 const unsigned char *sha1, int flag, void *cb_data)
 836 {
 837         struct commit_list **list = cb_data;
 838         struct object *object = parse_object(sha1);
 839         if (!object)
 840                 return 0;
 841         if (object->type == OBJ_TAG) {
 842                 object = deref_tag(object, path, strlen(path));
 843                 if (!object)
 844                         return 0;
 845         }
 846         if (object->type != OBJ_COMMIT)
 847                 return 0;
 848         commit_list_insert((struct commit *)object, list);
 849         return 0;
 850 }
 851
 852 static int get_sha1_oneline(const char *prefix, unsigned char *sha1,
 853                             struct commit_list *list)
 854 {
 855         struct commit_list *backup = NULL, *l;
 856         int found = 0;
 857         regex_t regex;
 858
 859         if (prefix[0] == '!') {
 860                 if (prefix[1] != '!')
 861                         die ("Invalid search pattern: %s", prefix);
 862                 prefix++;
 863         }
 864
 865         if (regcomp(&regex, prefix, REG_EXTENDED))
 866                 die("Invalid search pattern: %s", prefix);
 867
 868         for (l = list; l; l = l->next) {
 869                 l->item->object.flags |= ONELINE_SEEN;
 870                 commit_list_insert(l->item, &backup);
 871         }
 872         while (list) {
 873                 const char *p, *buf;
 874                 struct commit *commit;
 875                 int matches;
 876
 877                 commit = pop_most_recent_commit(&list, ONELINE_SEEN);
 878                 if (!parse_object(commit->object.sha1))
 879                         continue;
 880                 buf = get_commit_buffer(commit, NULL);
 881                 p = strstr(buf, "\n\n");
 882                 matches = p && !regexec(&regex, p + 2, 0, NULL, 0);
 883                 unuse_commit_buffer(commit, buf);
 884
 885                 if (matches) {
 886                         hashcpy(sha1, commit->object.sha1);
 887                         found = 1;
 888                         break;
 889                 }
 890         }
 891         regfree(&regex);
 892         free_commit_list(list);
 893         for (l = backup; l; l = l->next)
 894                 clear_commit_marks(l->item, ONELINE_SEEN);
 895         free_commit_list(backup);
 896         return found ? 0 : -1;
 897 }
 898
 899 struct grab_nth_branch_switch_cbdata {
 900         int remaining;
 901         struct strbuf buf;
 902 };
 903
 904 static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
 905                                   const char *email, unsigned long timestamp, int tz,
 906                                   const char *message, void *cb_data)
 907 {
 908         struct grab_nth_branch_switch_cbdata *cb = cb_data;
 909         const char *match = NULL, *target = NULL;
 910         size_t len;
 911
 912         if (skip_prefix(message, "checkout: moving from ", &match))
 913                 target = strstr(match, " to ");
 914
 915         if (!match || !target)
 916                 return 0;
 917         if (--(cb->remaining) == 0) {
 918                 len = target - match;
 919                 strbuf_reset(&cb->buf);
 920                 strbuf_add(&cb->buf, match, len);
 921                 return 1; /* we are done */
 922         }
 923         return 0;
 924 }
 925
 926 /*
 927  * Parse @{-N} syntax, return the number of characters parsed
 928  * if successful; otherwise signal an error with negative value.
 929  */
 930 static int interpret_nth_prior_checkout(const char *name, int namelen,
 931                                         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 (namelen < 4)
 940                 return -1;
 941         if (name[0] != '@' || name[1] != '{' || name[2] != '-')
 942                 return -1;
 943         brace = memchr(name, '}', namelen);
 944         if (!brace)
 945                 return -1;
 946         nth = strtol(name + 3, &num_end, 10);
 947         if (num_end != brace)
 948                 return -1;
 949         if (nth <= 0)
 950                 return -1;
 951         cb.remaining = nth;
 952         strbuf_init(&cb.buf, 20);
 953
 954         retval = 0;
 955         if (0 < for_each_reflog_ent_reverse("HEAD", grab_nth_branch_switch, &cb)) {
 956                 strbuf_reset(buf);
 957                 strbuf_addbuf(buf, &cb.buf);
 958                 retval = brace - name + 1;
 959         }
 960
 961         strbuf_release(&cb.buf);
 962         return retval;
 963 }
 964
 965 int get_sha1_mb(const char *name, unsigned char *sha1)
 966 {
 967         struct commit *one, *two;
 968         struct commit_list *mbs;
 969         unsigned char sha1_tmp[20];
 970         const char *dots;
 971         int st;
 972
 973         dots = strstr(name, "...");
 974         if (!dots)
 975                 return get_sha1(name, sha1);
 976         if (dots == name)
 977                 st = get_sha1("HEAD", sha1_tmp);
 978         else {
 979                 struct strbuf sb;
 980                 strbuf_init(&sb, dots - name);
 981                 strbuf_add(&sb, name, dots - name);
 982                 st = get_sha1_committish(sb.buf, sha1_tmp);
 983                 strbuf_release(&sb);
 984         }
 985         if (st)
 986                 return st;
 987         one = lookup_commit_reference_gently(sha1_tmp, 0);
 988         if (!one)
 989                 return -1;
 990
 991         if (get_sha1_committish(dots[3] ? (dots + 3) : "HEAD", sha1_tmp))
 992                 return -1;
 993         two = lookup_commit_reference_gently(sha1_tmp, 0);
 994         if (!two)
 995                 return -1;
 996         mbs = get_merge_bases(one, two);
 997         if (!mbs || mbs->next)
 998                 st = -1;
 999         else {
1000                 st = 0;
1001                 hashcpy(sha1, mbs->item->object.sha1);
1002         }
1003         free_commit_list(mbs);
1004         return st;
1005 }
1006
1007 /* parse @something syntax, when 'something' is not {.*} */
1008 static int interpret_empty_at(const char *name, int namelen, int len, struct strbuf *buf)
1009 {
1010         const char *next;
1011
1012         if (len || name[1] == '{')
1013                 return -1;
1014
1015         /* make sure it's a single @, or @@{.*}, not @foo */
1016         next = memchr(name + len + 1, '@', namelen - len - 1);
1017         if (next && next[1] != '{')
1018                 return -1;
1019         if (!next)
1020                 next = name + namelen;
1021         if (next != name + 1)
1022                 return -1;
1023
1024         strbuf_reset(buf);
1025         strbuf_add(buf, "HEAD", 4);
1026         return 1;
1027 }
1028
1029 static int reinterpret(const char *name, int namelen, int len, struct strbuf *buf)
1030 {
1031         /* we have extra data, which might need further processing */
1032         struct strbuf tmp = STRBUF_INIT;
1033         int used = buf->len;
1034         int ret;
1035
1036         strbuf_add(buf, name + len, namelen - len);
1037         ret = interpret_branch_name(buf->buf, buf->len, &tmp);
1038         /* that data was not interpreted, remove our cruft */
1039         if (ret < 0) {
1040                 strbuf_setlen(buf, used);
1041                 return len;
1042         }
1043         strbuf_reset(buf);
1044         strbuf_addbuf(buf, &tmp);
1045         strbuf_release(&tmp);
1046         /* tweak for size of {-N} versus expanded ref name */
1047         return ret - used + len;
1048 }
1049
1050 static void set_shortened_ref(struct strbuf *buf, const char *ref)
1051 {
1052         char *s = shorten_unambiguous_ref(ref, 0);
1053         strbuf_reset(buf);
1054         strbuf_addstr(buf, s);
1055         free(s);
1056 }
1057
1058 static const char *get_upstream_branch(const char *branch_buf, int len)
1059 {
1060         char *branch = xstrndup(branch_buf, len);
1061         struct branch *upstream = branch_get(*branch ? branch : NULL);
1062
1063         /*
1064          * Upstream can be NULL only if branch refers to HEAD and HEAD
1065          * points to something different than a branch.
1066          */
1067         if (!upstream)
1068                 die(_("HEAD does not point to a branch"));
1069         if (!upstream->merge || !upstream->merge[0]->dst) {
1070                 if (!ref_exists(upstream->refname))
1071                         die(_("No such branch: '%s'"), branch);
1072                 if (!upstream->merge) {
1073                         die(_("No upstream configured for branch '%s'"),
1074                                 upstream->name);
1075                 }
1076                 die(
1077                         _("Upstream branch '%s' not stored as a remote-tracking branch"),
1078                         upstream->merge[0]->src);
1079         }
1080         free(branch);
1081
1082         return upstream->merge[0]->dst;
1083 }
1084
1085 static int interpret_upstream_mark(const char *name, int namelen,
1086                                    int at, struct strbuf *buf)
1087 {
1088         int len;
1089
1090         len = upstream_mark(name + at, namelen - at);
1091         if (!len)
1092                 return -1;
1093
1094         if (memchr(name, ':', at))
1095                 return -1;
1096
1097         set_shortened_ref(buf, get_upstream_branch(name, at));
1098         return len + at;
1099 }
1100
1101 /*
1102  * This reads short-hand syntax that not only evaluates to a commit
1103  * object name, but also can act as if the end user spelled the name
1104  * of the branch from the command line.
1105  *
1106  * - "@{-N}" finds the name of the Nth previous branch we were on, and
1107  *   places the name of the branch in the given buf and returns the
1108  *   number of characters parsed if successful.
1109  *
1110  * - "<branch>@{upstream}" finds the name of the other ref that
1111  *   <branch> is configured to merge with (missing <branch> defaults
1112  *   to the current branch), and places the name of the branch in the
1113  *   given buf and returns the number of characters parsed if
1114  *   successful.
1115  *
1116  * If the input is not of the accepted format, it returns a negative
1117  * number to signal an error.
1118  *
1119  * If the input was ok but there are not N branch switches in the
1120  * reflog, it returns 0.
1121  */
1122 int interpret_branch_name(const char *name, int namelen, struct strbuf *buf)
1123 {
1124         char *at;
1125         const char *start;
1126         int len = interpret_nth_prior_checkout(name, namelen, buf);
1127
1128         if (!namelen)
1129                 namelen = strlen(name);
1130
1131         if (!len) {
1132                 return len; /* syntax Ok, not enough switches */
1133         } else if (len > 0) {
1134                 if (len == namelen)
1135                         return len; /* consumed all */
1136                 else
1137                         return reinterpret(name, namelen, len, buf);
1138         }
1139
1140         for (start = name;
1141              (at = memchr(start, '@', namelen - (start - name)));
1142              start = at + 1) {
1143
1144                 len = interpret_empty_at(name, namelen, at - name, buf);
1145                 if (len > 0)
1146                         return reinterpret(name, namelen, len, buf);
1147
1148                 len = interpret_upstream_mark(name, namelen, at - name, buf);
1149                 if (len > 0)
1150                         return len;
1151         }
1152
1153         return -1;
1154 }
1155
1156 int strbuf_branchname(struct strbuf *sb, const char *name)
1157 {
1158         int len = strlen(name);
1159         int used = interpret_branch_name(name, len, sb);
1160
1161         if (used == len)
1162                 return 0;
1163         if (used < 0)
1164                 used = 0;
1165         strbuf_add(sb, name + used, len - used);
1166         return len;
1167 }
1168
1169 int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
1170 {
1171         strbuf_branchname(sb, name);
1172         if (name[0] == '-')
1173                 return -1;
1174         strbuf_splice(sb, 0, 0, "refs/heads/", 11);
1175         return check_refname_format(sb->buf, 0);
1176 }
1177
1178 /*
1179  * This is like "get_sha1_basic()", except it allows "sha1 expressions",
1180  * notably "xyz^" for "parent of xyz"
1181  */
1182 int get_sha1(const char *name, unsigned char *sha1)
1183 {
1184         struct object_context unused;
1185         return get_sha1_with_context(name, 0, sha1, &unused);
1186 }
1187
1188 /*
1189  * Many callers know that the user meant to name a commit-ish by
1190  * syntactical positions where the object name appears.  Calling this
1191  * function allows the machinery to disambiguate shorter-than-unique
1192  * abbreviated object names between commit-ish and others.
1193  *
1194  * Note that this does NOT error out when the named object is not a
1195  * commit-ish. It is merely to give a hint to the disambiguation
1196  * machinery.
1197  */
1198 int get_sha1_committish(const char *name, unsigned char *sha1)
1199 {
1200         struct object_context unused;
1201         return get_sha1_with_context(name, GET_SHA1_COMMITTISH,
1202                                      sha1, &unused);
1203 }
1204
1205 int get_sha1_treeish(const char *name, unsigned char *sha1)
1206 {
1207         struct object_context unused;
1208         return get_sha1_with_context(name, GET_SHA1_TREEISH,
1209                                      sha1, &unused);
1210 }
1211
1212 int get_sha1_commit(const char *name, unsigned char *sha1)
1213 {
1214         struct object_context unused;
1215         return get_sha1_with_context(name, GET_SHA1_COMMIT,
1216                                      sha1, &unused);
1217 }
1218
1219 int get_sha1_tree(const char *name, unsigned char *sha1)
1220 {
1221         struct object_context unused;
1222         return get_sha1_with_context(name, GET_SHA1_TREE,
1223                                      sha1, &unused);
1224 }
1225
1226 int get_sha1_blob(const char *name, unsigned char *sha1)
1227 {
1228         struct object_context unused;
1229         return get_sha1_with_context(name, GET_SHA1_BLOB,
1230                                      sha1, &unused);
1231 }
1232
1233 /* Must be called only when object_name:filename doesn't exist. */
1234 static void diagnose_invalid_sha1_path(const char *prefix,
1235                                        const char *filename,
1236                                        const unsigned char *tree_sha1,
1237                                        const char *object_name,
1238                                        int object_name_len)
1239 {
1240         struct stat st;
1241         unsigned char sha1[20];
1242         unsigned mode;
1243
1244         if (!prefix)
1245                 prefix = "";
1246
1247         if (!lstat(filename, &st))
1248                 die("Path '%s' exists on disk, but not in '%.*s'.",
1249                     filename, object_name_len, object_name);
1250         if (errno == ENOENT || errno == ENOTDIR) {
1251                 char *fullname = xstrfmt("%s%s", prefix, filename);
1252
1253                 if (!get_tree_entry(tree_sha1, fullname,
1254                                     sha1, &mode)) {
1255                         die("Path '%s' exists, but not '%s'.\n"
1256                             "Did you mean '%.*s:%s' aka '%.*s:./%s'?",
1257                             fullname,
1258                             filename,
1259                             object_name_len, object_name,
1260                             fullname,
1261                             object_name_len, object_name,
1262                             filename);
1263                 }
1264                 die("Path '%s' does not exist in '%.*s'",
1265                     filename, object_name_len, object_name);
1266         }
1267 }
1268
1269 /* Must be called only when :stage:filename doesn't exist. */
1270 static void diagnose_invalid_index_path(int stage,
1271                                         const char *prefix,
1272                                         const char *filename)
1273 {
1274         struct stat st;
1275         const struct cache_entry *ce;
1276         int pos;
1277         unsigned namelen = strlen(filename);
1278         unsigned fullnamelen;
1279         char *fullname;
1280
1281         if (!prefix)
1282                 prefix = "";
1283
1284         /* Wrong stage number? */
1285         pos = cache_name_pos(filename, namelen);
1286         if (pos < 0)
1287                 pos = -pos - 1;
1288         if (pos < active_nr) {
1289                 ce = active_cache[pos];
1290                 if (ce_namelen(ce) == namelen &&
1291                     !memcmp(ce->name, filename, namelen))
1292                         die("Path '%s' is in the index, but not at stage %d.\n"
1293                             "Did you mean ':%d:%s'?",
1294                             filename, stage,
1295                             ce_stage(ce), filename);
1296         }
1297
1298         /* Confusion between relative and absolute filenames? */
1299         fullnamelen = namelen + strlen(prefix);
1300         fullname = xmalloc(fullnamelen + 1);
1301         strcpy(fullname, prefix);
1302         strcat(fullname, filename);
1303         pos = cache_name_pos(fullname, fullnamelen);
1304         if (pos < 0)
1305                 pos = -pos - 1;
1306         if (pos < active_nr) {
1307                 ce = active_cache[pos];
1308                 if (ce_namelen(ce) == fullnamelen &&
1309                     !memcmp(ce->name, fullname, fullnamelen))
1310                         die("Path '%s' is in the index, but not '%s'.\n"
1311                             "Did you mean ':%d:%s' aka ':%d:./%s'?",
1312                             fullname, filename,
1313                             ce_stage(ce), fullname,
1314                             ce_stage(ce), filename);
1315         }
1316
1317         if (!lstat(filename, &st))
1318                 die("Path '%s' exists on disk, but not in the index.", filename);
1319         if (errno == ENOENT || errno == ENOTDIR)
1320                 die("Path '%s' does not exist (neither on disk nor in the index).",
1321                     filename);
1322
1323         free(fullname);
1324 }
1325
1326
1327 static char *resolve_relative_path(const char *rel)
1328 {
1329         if (!starts_with(rel, "./") && !starts_with(rel, "../"))
1330                 return NULL;
1331
1332         if (!startup_info)
1333                 die("BUG: startup_info struct is not initialized.");
1334
1335         if (!is_inside_work_tree())
1336                 die("relative path syntax can't be used outside working tree.");
1337
1338         /* die() inside prefix_path() if resolved path is outside worktree */
1339         return prefix_path(startup_info->prefix,
1340                            startup_info->prefix ? strlen(startup_info->prefix) : 0,
1341                            rel);
1342 }
1343
1344 static int get_sha1_with_context_1(const char *name,
1345                                    unsigned flags,
1346                                    const char *prefix,
1347                                    unsigned char *sha1,
1348                                    struct object_context *oc)
1349 {
1350         int ret, bracket_depth;
1351         int namelen = strlen(name);
1352         const char *cp;
1353         int only_to_die = flags & GET_SHA1_ONLY_TO_DIE;
1354
1355         memset(oc, 0, sizeof(*oc));
1356         oc->mode = S_IFINVALID;
1357         ret = get_sha1_1(name, namelen, sha1, flags);
1358         if (!ret)
1359                 return ret;
1360         /*
1361          * sha1:path --> object name of path in ent sha1
1362          * :path -> object name of absolute path in index
1363          * :./path -> object name of path relative to cwd in index
1364          * :[0-3]:path -> object name of path in index at stage
1365          * :/foo -> recent commit matching foo
1366          */
1367         if (name[0] == ':') {
1368                 int stage = 0;
1369                 const struct cache_entry *ce;
1370                 char *new_path = NULL;
1371                 int pos;
1372                 if (!only_to_die && namelen > 2 && name[1] == '/') {
1373                         struct commit_list *list = NULL;
1374                         for_each_ref(handle_one_ref, &list);
1375                         commit_list_sort_by_date(&list);
1376                         return get_sha1_oneline(name + 2, sha1, list);
1377                 }
1378                 if (namelen < 3 ||
1379                     name[2] != ':' ||
1380                     name[1] < '0' || '3' < name[1])
1381                         cp = name + 1;
1382                 else {
1383                         stage = name[1] - '0';
1384                         cp = name + 3;
1385                 }
1386                 new_path = resolve_relative_path(cp);
1387                 if (!new_path) {
1388                         namelen = namelen - (cp - name);
1389                 } else {
1390                         cp = new_path;
1391                         namelen = strlen(cp);
1392                 }
1393
1394                 strncpy(oc->path, cp,
1395                         sizeof(oc->path));
1396                 oc->path[sizeof(oc->path)-1] = '\0';
1397
1398                 if (!active_cache)
1399                         read_cache();
1400                 pos = cache_name_pos(cp, namelen);
1401                 if (pos < 0)
1402                         pos = -pos - 1;
1403                 while (pos < active_nr) {
1404                         ce = active_cache[pos];
1405                         if (ce_namelen(ce) != namelen ||
1406                             memcmp(ce->name, cp, namelen))
1407                                 break;
1408                         if (ce_stage(ce) == stage) {
1409                                 hashcpy(sha1, ce->sha1);
1410                                 oc->mode = ce->ce_mode;
1411                                 free(new_path);
1412                                 return 0;
1413                         }
1414                         pos++;
1415                 }
1416                 if (only_to_die && name[1] && name[1] != '/')
1417                         diagnose_invalid_index_path(stage, prefix, cp);
1418                 free(new_path);
1419                 return -1;
1420         }
1421         for (cp = name, bracket_depth = 0; *cp; cp++) {
1422                 if (*cp == '{')
1423                         bracket_depth++;
1424                 else if (bracket_depth && *cp == '}')
1425                         bracket_depth--;
1426                 else if (!bracket_depth && *cp == ':')
1427                         break;
1428         }
1429         if (*cp == ':') {
1430                 unsigned char tree_sha1[20];
1431                 int len = cp - name;
1432                 if (!get_sha1_1(name, len, tree_sha1, GET_SHA1_TREEISH)) {
1433                         const char *filename = cp+1;
1434                         char *new_filename = NULL;
1435
1436                         new_filename = resolve_relative_path(filename);
1437                         if (new_filename)
1438                                 filename = new_filename;
1439                         ret = get_tree_entry(tree_sha1, filename, sha1, &oc->mode);
1440                         if (ret && only_to_die) {
1441                                 diagnose_invalid_sha1_path(prefix, filename,
1442                                                            tree_sha1,
1443                                                            name, len);
1444                         }
1445                         hashcpy(oc->tree, tree_sha1);
1446                         strncpy(oc->path, filename,
1447                                 sizeof(oc->path));
1448                         oc->path[sizeof(oc->path)-1] = '\0';
1449
1450                         free(new_filename);
1451                         return ret;
1452                 } else {
1453                         if (only_to_die)
1454                                 die("Invalid object name '%.*s'.", len, name);
1455                 }
1456         }
1457         return ret;
1458 }
1459
1460 /*
1461  * Call this function when you know "name" given by the end user must
1462  * name an object but it doesn't; the function _may_ die with a better
1463  * diagnostic message than "no such object 'name'", e.g. "Path 'doc' does not
1464  * exist in 'HEAD'" when given "HEAD:doc", or it may return in which case
1465  * you have a chance to diagnose the error further.
1466  */
1467 void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
1468 {
1469         struct object_context oc;
1470         unsigned char sha1[20];
1471         get_sha1_with_context_1(name, GET_SHA1_ONLY_TO_DIE, prefix, sha1, &oc);
1472 }
1473
1474 int get_sha1_with_context(const char *str, unsigned flags, unsigned char *sha1, struct object_context *orc)
1475 {
1476         return get_sha1_with_context_1(str, flags, NULL, sha1, orc);
1477 }