git.oblomov.eu Git - git/blob - 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 #include "dir.h"
  10
  11 static int get_sha1_oneline(const char *, unsigned char *, struct commit_list *);
  12
  13 typedef int (*disambiguate_hint_fn)(const unsigned char *, void *);
  14
  15 struct disambiguate_state {
  16         disambiguate_hint_fn fn;
  17         void *cb_data;
  18         unsigned char candidate[20];
  19         unsigned candidate_exists:1;
  20         unsigned candidate_checked:1;
  21         unsigned candidate_ok:1;
  22         unsigned disambiguate_fn_used:1;
  23         unsigned ambiguous:1;
  24         unsigned always_call_fn:1;
  25 };
  26
  27 static void update_candidates(struct disambiguate_state *ds, const unsigned char *current)
  28 {
  29         if (ds->always_call_fn) {
  30                 ds->ambiguous = ds->fn(current, ds->cb_data) ? 1 : 0;
  31                 return;
  32         }
  33         if (!ds->candidate_exists) {
  34                 /* this is the first candidate */
  35                 hashcpy(ds->candidate, current);
  36                 ds->candidate_exists = 1;
  37                 return;
  38         } else if (!hashcmp(ds->candidate, current)) {
  39                 /* the same as what we already have seen */
  40                 return;
  41         }
  42
  43         if (!ds->fn) {
  44                 /* cannot disambiguate between ds->candidate and current */
  45                 ds->ambiguous = 1;
  46                 return;
  47         }
  48
  49         if (!ds->candidate_checked) {
  50                 ds->candidate_ok = ds->fn(ds->candidate, ds->cb_data);
  51                 ds->disambiguate_fn_used = 1;
  52                 ds->candidate_checked = 1;
  53         }
  54
  55         if (!ds->candidate_ok) {
  56                 /* discard the candidate; we know it does not satisfy fn */
  57                 hashcpy(ds->candidate, current);
  58                 ds->candidate_checked = 0;
  59                 return;
  60         }
  61
  62         /* if we reach this point, we know ds->candidate satisfies fn */
  63         if (ds->fn(current, ds->cb_data)) {
  64                 /*
  65                  * if both current and candidate satisfy fn, we cannot
  66                  * disambiguate.
  67                  */
  68                 ds->candidate_ok = 0;
  69                 ds->ambiguous = 1;
  70         }
  71
  72         /* otherwise, current can be discarded and candidate is still good */
  73 }
  74
  75 static void find_short_object_filename(int len, const char *hex_pfx, struct disambiguate_state *ds)
  76 {
  77         struct alternate_object_database *alt;
  78         char hex[40];
  79         static struct alternate_object_database *fakeent;
  80
  81         if (!fakeent) {
  82                 /*
  83                  * Create a "fake" alternate object database that
  84                  * points to our own object database, to make it
  85                  * easier to get a temporary working space in
  86                  * alt->name/alt->base while iterating over the
  87                  * object databases including our own.
  88                  */
  89                 fakeent = alloc_alt_odb(get_object_directory());
  90         }
  91         fakeent->next = alt_odb_list;
  92
  93         xsnprintf(hex, sizeof(hex), "%.2s", hex_pfx);
  94         for (alt = fakeent; alt && !ds->ambiguous; alt = alt->next) {
  95                 struct strbuf *buf = alt_scratch_buf(alt);
  96                 struct dirent *de;
  97                 DIR *dir;
  98
  99                 strbuf_addf(buf, "%.2s/", hex_pfx);
 100                 dir = opendir(buf->buf);
 101                 if (!dir)
 102                         continue;
 103
 104                 while (!ds->ambiguous && (de = readdir(dir)) != NULL) {
 105                         unsigned char sha1[20];
 106
 107                         if (strlen(de->d_name) != 38)
 108                                 continue;
 109                         if (memcmp(de->d_name, hex_pfx + 2, len - 2))
 110                                 continue;
 111                         memcpy(hex + 2, de->d_name, 38);
 112                         if (!get_sha1_hex(hex, sha1))
 113                                 update_candidates(ds, sha1);
 114                 }
 115                 closedir(dir);
 116         }
 117 }
 118
 119 static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
 120 {
 121         do {
 122                 if (*a != *b)
 123                         return 0;
 124                 a++;
 125                 b++;
 126                 len -= 2;
 127         } while (len > 1);
 128         if (len)
 129                 if ((*a ^ *b) & 0xf0)
 130                         return 0;
 131         return 1;
 132 }
 133
 134 static void unique_in_pack(int len,
 135                           const unsigned char *bin_pfx,
 136                            struct packed_git *p,
 137                            struct disambiguate_state *ds)
 138 {
 139         uint32_t num, last, i, first = 0;
 140         const unsigned char *current = NULL;
 141
 142         open_pack_index(p);
 143         num = p->num_objects;
 144         last = num;
 145         while (first < last) {
 146                 uint32_t mid = (first + last) / 2;
 147                 const unsigned char *current;
 148                 int cmp;
 149
 150                 current = nth_packed_object_sha1(p, mid);
 151                 cmp = hashcmp(bin_pfx, current);
 152                 if (!cmp) {
 153                         first = mid;
 154                         break;
 155                 }
 156                 if (cmp > 0) {
 157                         first = mid+1;
 158                         continue;
 159                 }
 160                 last = mid;
 161         }
 162
 163         /*
 164          * At this point, "first" is the location of the lowest object
 165          * with an object name that could match "bin_pfx".  See if we have
 166          * 0, 1 or more objects that actually match(es).
 167          */
 168         for (i = first; i < num && !ds->ambiguous; i++) {
 169                 current = nth_packed_object_sha1(p, i);
 170                 if (!match_sha(len, bin_pfx, current))
 171                         break;
 172                 update_candidates(ds, current);
 173         }
 174 }
 175
 176 static void find_short_packed_object(int len, const unsigned char *bin_pfx,
 177                                      struct disambiguate_state *ds)
 178 {
 179         struct packed_git *p;
 180
 181         prepare_packed_git();
 182         for (p = packed_git; p && !ds->ambiguous; p = p->next)
 183                 unique_in_pack(len, bin_pfx, p, ds);
 184 }
 185
 186 #define SHORT_NAME_NOT_FOUND (-1)
 187 #define SHORT_NAME_AMBIGUOUS (-2)
 188
 189 static int finish_object_disambiguation(struct disambiguate_state *ds,
 190                                         unsigned char *sha1)
 191 {
 192         if (ds->ambiguous)
 193                 return SHORT_NAME_AMBIGUOUS;
 194
 195         if (!ds->candidate_exists)
 196                 return SHORT_NAME_NOT_FOUND;
 197
 198         if (!ds->candidate_checked)
 199                 /*
 200                  * If this is the only candidate, there is no point
 201                  * calling the disambiguation hint callback.
 202                  *
 203                  * On the other hand, if the current candidate
 204                  * replaced an earlier candidate that did _not_ pass
 205                  * the disambiguation hint callback, then we do have
 206                  * more than one objects that match the short name
 207                  * given, so we should make sure this one matches;
 208                  * otherwise, if we discovered this one and the one
 209                  * that we previously discarded in the reverse order,
 210                  * we would end up showing different results in the
 211                  * same repository!
 212                  */
 213                 ds->candidate_ok = (!ds->disambiguate_fn_used ||
 214                                     ds->fn(ds->candidate, ds->cb_data));
 215
 216         if (!ds->candidate_ok)
 217                 return SHORT_NAME_AMBIGUOUS;
 218
 219         hashcpy(sha1, ds->candidate);
 220         return 0;
 221 }
 222
 223 static int disambiguate_commit_only(const unsigned char *sha1, void *cb_data_unused)
 224 {
 225         int kind = sha1_object_info(sha1, NULL);
 226         return kind == OBJ_COMMIT;
 227 }
 228
 229 static int disambiguate_committish_only(const unsigned char *sha1, void *cb_data_unused)
 230 {
 231         struct object *obj;
 232         int kind;
 233
 234         kind = sha1_object_info(sha1, NULL);
 235         if (kind == OBJ_COMMIT)
 236                 return 1;
 237         if (kind != OBJ_TAG)
 238                 return 0;
 239
 240         /* We need to do this the hard way... */
 241         obj = deref_tag(parse_object(sha1), NULL, 0);
 242         if (obj && obj->type == OBJ_COMMIT)
 243                 return 1;
 244         return 0;
 245 }
 246
 247 static int disambiguate_tree_only(const unsigned char *sha1, void *cb_data_unused)
 248 {
 249         int kind = sha1_object_info(sha1, NULL);
 250         return kind == OBJ_TREE;
 251 }
 252
 253 static int disambiguate_treeish_only(const unsigned char *sha1, void *cb_data_unused)
 254 {
 255         struct object *obj;
 256         int kind;
 257
 258         kind = sha1_object_info(sha1, NULL);
 259         if (kind == OBJ_TREE || kind == OBJ_COMMIT)
 260                 return 1;
 261         if (kind != OBJ_TAG)
 262                 return 0;
 263
 264         /* We need to do this the hard way... */
 265         obj = deref_tag(lookup_object(sha1), NULL, 0);
 266         if (obj && (obj->type == OBJ_TREE || obj->type == OBJ_COMMIT))
 267                 return 1;
 268         return 0;
 269 }
 270
 271 static int disambiguate_blob_only(const unsigned char *sha1, void *cb_data_unused)
 272 {
 273         int kind = sha1_object_info(sha1, NULL);
 274         return kind == OBJ_BLOB;
 275 }
 276
 277 static int prepare_prefixes(const char *name, int len,
 278                             unsigned char *bin_pfx,
 279                             char *hex_pfx)
 280 {
 281         int i;
 282
 283         hashclr(bin_pfx);
 284         memset(hex_pfx, 'x', 40);
 285         for (i = 0; i < len ;i++) {
 286                 unsigned char c = name[i];
 287                 unsigned char val;
 288                 if (c >= '0' && c <= '9')
 289                         val = c - '0';
 290                 else if (c >= 'a' && c <= 'f')
 291                         val = c - 'a' + 10;
 292                 else if (c >= 'A' && c <='F') {
 293                         val = c - 'A' + 10;
 294                         c -= 'A' - 'a';
 295                 }
 296                 else
 297                         return -1;
 298                 hex_pfx[i] = c;
 299                 if (!(i & 1))
 300                         val <<= 4;
 301                 bin_pfx[i >> 1] |= val;
 302         }
 303         return 0;
 304 }
 305
 306 static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 307                           unsigned flags)
 308 {
 309         int status;
 310         char hex_pfx[40];
 311         unsigned char bin_pfx[20];
 312         struct disambiguate_state ds;
 313         int quietly = !!(flags & GET_SHA1_QUIETLY);
 314
 315         if (len < MINIMUM_ABBREV || len > 40)
 316                 return -1;
 317         if (prepare_prefixes(name, len, bin_pfx, hex_pfx) < 0)
 318                 return -1;
 319
 320         prepare_alt_odb();
 321
 322         memset(&ds, 0, sizeof(ds));
 323         if (flags & GET_SHA1_COMMIT)
 324                 ds.fn = disambiguate_commit_only;
 325         else if (flags & GET_SHA1_COMMITTISH)
 326                 ds.fn = disambiguate_committish_only;
 327         else if (flags & GET_SHA1_TREE)
 328                 ds.fn = disambiguate_tree_only;
 329         else if (flags & GET_SHA1_TREEISH)
 330                 ds.fn = disambiguate_treeish_only;
 331         else if (flags & GET_SHA1_BLOB)
 332                 ds.fn = disambiguate_blob_only;
 333
 334         find_short_object_filename(len, hex_pfx, &ds);
 335         find_short_packed_object(len, bin_pfx, &ds);
 336         status = finish_object_disambiguation(&ds, sha1);
 337
 338         if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
 339                 return error("short SHA1 %.*s is ambiguous.", len, hex_pfx);
 340         return status;
 341 }
 342
 343 int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
 344 {
 345         char hex_pfx[40];
 346         unsigned char bin_pfx[20];
 347         struct disambiguate_state ds;
 348         int len = strlen(prefix);
 349
 350         if (len < MINIMUM_ABBREV || len > 40)
 351                 return -1;
 352         if (prepare_prefixes(prefix, len, bin_pfx, hex_pfx) < 0)
 353                 return -1;
 354
 355         prepare_alt_odb();
 356
 357         memset(&ds, 0, sizeof(ds));
 358         ds.always_call_fn = 1;
 359         ds.cb_data = cb_data;
 360         ds.fn = fn;
 361
 362         find_short_object_filename(len, hex_pfx, &ds);
 363         find_short_packed_object(len, bin_pfx, &ds);
 364         return ds.ambiguous;
 365 }
 366
 367 int find_unique_abbrev_r(char *hex, const unsigned char *sha1, int len)
 368 {
 369         int status, exists;
 370
 371         sha1_to_hex_r(hex, sha1);
 372         if (len == 40 || !len)
 373                 return 40;
 374         exists = has_sha1_file(sha1);
 375         while (len < 40) {
 376                 unsigned char sha1_ret[20];
 377                 status = get_short_sha1(hex, len, sha1_ret, GET_SHA1_QUIETLY);
 378                 if (exists
 379                     ? !status
 380                     : status == SHORT_NAME_NOT_FOUND) {
 381                         hex[len] = 0;
 382                         return len;
 383                 }
 384                 len++;
 385         }
 386         return len;
 387 }
 388
 389 const char *find_unique_abbrev(const unsigned char *sha1, int len)
 390 {
 391         static char hex[GIT_SHA1_HEXSZ + 1];
 392         find_unique_abbrev_r(hex, sha1, len);
 393         return hex;
 394 }
 395
 396 static int ambiguous_path(const char *path, int len)
 397 {
 398         int slash = 1;
 399         int cnt;
 400
 401         for (cnt = 0; cnt < len; cnt++) {
 402                 switch (*path++) {
 403                 case '\0':
 404                         break;
 405                 case '/':
 406                         if (slash)
 407                                 break;
 408                         slash = 1;
 409                         continue;
 410                 case '.':
 411                         continue;
 412                 default:
 413                         slash = 0;
 414                         continue;
 415                 }
 416                 break;
 417         }
 418         return slash;
 419 }
 420
 421 static inline int at_mark(const char *string, int len,
 422                           const char **suffix, int nr)
 423 {
 424         int i;
 425
 426         for (i = 0; i < nr; i++) {
 427                 int suffix_len = strlen(suffix[i]);
 428                 if (suffix_len <= len
 429                     && !memcmp(string, suffix[i], suffix_len))
 430                         return suffix_len;
 431         }
 432         return 0;
 433 }
 434
 435 static inline int upstream_mark(const char *string, int len)
 436 {
 437         const char *suffix[] = { "@{upstream}", "@{u}" };
 438         return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
 439 }
 440
 441 static inline int push_mark(const char *string, int len)
 442 {
 443         const char *suffix[] = { "@{push}" };
 444         return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
 445 }
 446
 447 static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags);
 448 static int interpret_nth_prior_checkout(const char *name, int namelen, struct strbuf *buf);
 449
 450 static int get_sha1_basic(const char *str, int len, unsigned char *sha1,
 451                           unsigned int flags)
 452 {
 453         static const char *warn_msg = "refname '%.*s' is ambiguous.";
 454         static const char *object_name_msg = N_(
 455         "Git normally never creates a ref that ends with 40 hex characters\n"
 456         "because it will be ignored when you just specify 40-hex. These refs\n"
 457         "may be created by mistake. For example,\n"
 458         "\n"
 459         "  git checkout -b $br $(git rev-parse ...)\n"
 460         "\n"
 461         "where \"$br\" is somehow empty and a 40-hex ref is created. Please\n"
 462         "examine these refs and maybe delete them. Turn this message off by\n"
 463         "running \"git config advice.objectNameWarning false\"");
 464         unsigned char tmp_sha1[20];
 465         char *real_ref = NULL;
 466         int refs_found = 0;
 467         int at, reflog_len, nth_prior = 0;
 468
 469         if (len == 40 && !get_sha1_hex(str, sha1)) {
 470                 if (warn_ambiguous_refs && warn_on_object_refname_ambiguity) {
 471                         refs_found = dwim_ref(str, len, tmp_sha1, &real_ref);
 472                         if (refs_found > 0) {
 473                                 warning(warn_msg, len, str);
 474                                 if (advice_object_name_warning)
 475                                         fprintf(stderr, "%s\n", _(object_name_msg));
 476                         }
 477                         free(real_ref);
 478                 }
 479                 return 0;
 480         }
 481
 482         /* basic@{time or number or -number} format to query ref-log */
 483         reflog_len = at = 0;
 484         if (len && str[len-1] == '}') {
 485                 for (at = len-4; at >= 0; at--) {
 486                         if (str[at] == '@' && str[at+1] == '{') {
 487                                 if (str[at+2] == '-') {
 488                                         if (at != 0)
 489                                                 /* @{-N} not at start */
 490                                                 return -1;
 491                                         nth_prior = 1;
 492                                         continue;
 493                                 }
 494                                 if (!upstream_mark(str + at, len - at) &&
 495                                     !push_mark(str + at, len - at)) {
 496                                         reflog_len = (len-1) - (at+2);
 497                                         len = at;
 498                                 }
 499                                 break;
 500                         }
 501                 }
 502         }
 503
 504         /* Accept only unambiguous ref paths. */
 505         if (len && ambiguous_path(str, len))
 506                 return -1;
 507
 508         if (nth_prior) {
 509                 struct strbuf buf = STRBUF_INIT;
 510                 int detached;
 511
 512                 if (interpret_nth_prior_checkout(str, len, &buf) > 0) {
 513                         detached = (buf.len == 40 && !get_sha1_hex(buf.buf, sha1));
 514                         strbuf_release(&buf);
 515                         if (detached)
 516                                 return 0;
 517                 }
 518         }
 519
 520         if (!len && reflog_len)
 521                 /* allow "@{...}" to mean the current branch reflog */
 522                 refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
 523         else if (reflog_len)
 524                 refs_found = dwim_log(str, len, sha1, &real_ref);
 525         else
 526                 refs_found = dwim_ref(str, len, sha1, &real_ref);
 527
 528         if (!refs_found)
 529                 return -1;
 530
 531         if (warn_ambiguous_refs && !(flags & GET_SHA1_QUIETLY) &&
 532             (refs_found > 1 ||
 533              !get_short_sha1(str, len, tmp_sha1, GET_SHA1_QUIETLY)))
 534                 warning(warn_msg, len, str);
 535
 536         if (reflog_len) {
 537                 int nth, i;
 538                 unsigned long at_time;
 539                 unsigned long co_time;
 540                 int co_tz, co_cnt;
 541
 542                 /* Is it asking for N-th entry, or approxidate? */
 543                 for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 544                         char ch = str[at+2+i];
 545                         if ('0' <= ch && ch <= '9')
 546                                 nth = nth * 10 + ch - '0';
 547                         else
 548                                 nth = -1;
 549                 }
 550                 if (100000000 <= nth) {
 551                         at_time = nth;
 552                         nth = -1;
 553                 } else if (0 <= nth)
 554                         at_time = 0;
 555                 else {
 556                         int errors = 0;
 557                         char *tmp = xstrndup(str + at + 2, reflog_len);
 558                         at_time = approxidate_careful(tmp, &errors);
 559                         free(tmp);
 560                         if (errors) {
 561                                 free(real_ref);
 562                                 return -1;
 563                         }
 564                 }
 565                 if (read_ref_at(real_ref, flags, at_time, nth, sha1, NULL,
 566                                 &co_time, &co_tz, &co_cnt)) {
 567                         if (!len) {
 568                                 if (starts_with(real_ref, "refs/heads/")) {
 569                                         str = real_ref + 11;
 570                                         len = strlen(real_ref + 11);
 571                                 } else {
 572                                         /* detached HEAD */
 573                                         str = "HEAD";
 574                                         len = 4;
 575                                 }
 576                         }
 577                         if (at_time) {
 578                                 if (!(flags & GET_SHA1_QUIETLY)) {
 579                                         warning("Log for '%.*s' only goes "
 580                                                 "back to %s.", len, str,
 581                                                 show_date(co_time, co_tz, DATE_MODE(RFC2822)));
 582                                 }
 583                         } else {
 584                                 if (flags & GET_SHA1_QUIETLY) {
 585                                         exit(128);
 586                                 }
 587                                 die("Log for '%.*s' only has %d entries.",
 588                                     len, str, co_cnt);
 589                         }
 590                 }
 591         }
 592
 593         free(real_ref);
 594         return 0;
 595 }
 596
 597 static int get_parent(const char *name, int len,
 598                       unsigned char *result, int idx)
 599 {
 600         unsigned char sha1[20];
 601         int ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 602         struct commit *commit;
 603         struct commit_list *p;
 604
 605         if (ret)
 606                 return ret;
 607         commit = lookup_commit_reference(sha1);
 608         if (parse_commit(commit))
 609                 return -1;
 610         if (!idx) {
 611                 hashcpy(result, commit->object.oid.hash);
 612                 return 0;
 613         }
 614         p = commit->parents;
 615         while (p) {
 616                 if (!--idx) {
 617                         hashcpy(result, p->item->object.oid.hash);
 618                         return 0;
 619                 }
 620                 p = p->next;
 621         }
 622         return -1;
 623 }
 624
 625 static int get_nth_ancestor(const char *name, int len,
 626                             unsigned char *result, int generation)
 627 {
 628         unsigned char sha1[20];
 629         struct commit *commit;
 630         int ret;
 631
 632         ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 633         if (ret)
 634                 return ret;
 635         commit = lookup_commit_reference(sha1);
 636         if (!commit)
 637                 return -1;
 638
 639         while (generation--) {
 640                 if (parse_commit(commit) || !commit->parents)
 641                         return -1;
 642                 commit = commit->parents->item;
 643         }
 644         hashcpy(result, commit->object.oid.hash);
 645         return 0;
 646 }
 647
 648 struct object *peel_to_type(const char *name, int namelen,
 649                             struct object *o, enum object_type expected_type)
 650 {
 651         if (name && !namelen)
 652                 namelen = strlen(name);
 653         while (1) {
 654                 if (!o || (!o->parsed && !parse_object(o->oid.hash)))
 655                         return NULL;
 656                 if (expected_type == OBJ_ANY || o->type == expected_type)
 657                         return o;
 658                 if (o->type == OBJ_TAG)
 659                         o = ((struct tag*) o)->tagged;
 660                 else if (o->type == OBJ_COMMIT)
 661                         o = &(((struct commit *) o)->tree->object);
 662                 else {
 663                         if (name)
 664                                 error("%.*s: expected %s type, but the object "
 665                                       "dereferences to %s type",
 666                                       namelen, name, typename(expected_type),
 667                                       typename(o->type));
 668                         return NULL;
 669                 }
 670         }
 671 }
 672
 673 static int peel_onion(const char *name, int len, unsigned char *sha1)
 674 {
 675         unsigned char outer[20];
 676         const char *sp;
 677         unsigned int expected_type = 0;
 678         unsigned lookup_flags = 0;
 679         struct object *o;
 680
 681         /*
 682          * "ref^{type}" dereferences ref repeatedly until you cannot
 683          * dereference anymore, or you get an object of given type,
 684          * whichever comes first.  "ref^{}" means just dereference
 685          * tags until you get a non-tag.  "ref^0" is a shorthand for
 686          * "ref^{commit}".  "commit^{tree}" could be used to find the
 687          * top-level tree of the given commit.
 688          */
 689         if (len < 4 || name[len-1] != '}')
 690                 return -1;
 691
 692         for (sp = name + len - 1; name <= sp; sp--) {
 693                 int ch = *sp;
 694                 if (ch == '{' && name < sp && sp[-1] == '^')
 695                         break;
 696         }
 697         if (sp <= name)
 698                 return -1;
 699
 700         sp++; /* beginning of type name, or closing brace for empty */
 701         if (starts_with(sp, "commit}"))
 702                 expected_type = OBJ_COMMIT;
 703         else if (starts_with(sp, "tag}"))
 704                 expected_type = OBJ_TAG;
 705         else if (starts_with(sp, "tree}"))
 706                 expected_type = OBJ_TREE;
 707         else if (starts_with(sp, "blob}"))
 708                 expected_type = OBJ_BLOB;
 709         else if (starts_with(sp, "object}"))
 710                 expected_type = OBJ_ANY;
 711         else if (sp[0] == '}')
 712                 expected_type = OBJ_NONE;
 713         else if (sp[0] == '/')
 714                 expected_type = OBJ_COMMIT;
 715         else
 716                 return -1;
 717
 718         if (expected_type == OBJ_COMMIT)
 719                 lookup_flags = GET_SHA1_COMMITTISH;
 720         else if (expected_type == OBJ_TREE)
 721                 lookup_flags = GET_SHA1_TREEISH;
 722
 723         if (get_sha1_1(name, sp - name - 2, outer, lookup_flags))
 724                 return -1;
 725
 726         o = parse_object(outer);
 727         if (!o)
 728                 return -1;
 729         if (!expected_type) {
 730                 o = deref_tag(o, name, sp - name - 2);
 731                 if (!o || (!o->parsed && !parse_object(o->oid.hash)))
 732                         return -1;
 733                 hashcpy(sha1, o->oid.hash);
 734                 return 0;
 735         }
 736
 737         /*
 738          * At this point, the syntax look correct, so
 739          * if we do not get the needed object, we should
 740          * barf.
 741          */
 742         o = peel_to_type(name, len, o, expected_type);
 743         if (!o)
 744                 return -1;
 745
 746         hashcpy(sha1, o->oid.hash);
 747         if (sp[0] == '/') {
 748                 /* "$commit^{/foo}" */
 749                 char *prefix;
 750                 int ret;
 751                 struct commit_list *list = NULL;
 752
 753                 /*
 754                  * $commit^{/}. Some regex implementation may reject.
 755                  * We don't need regex anyway. '' pattern always matches.
 756                  */
 757                 if (sp[1] == '}')
 758                         return 0;
 759
 760                 prefix = xstrndup(sp + 1, name + len - 1 - (sp + 1));
 761                 commit_list_insert((struct commit *)o, &list);
 762                 ret = get_sha1_oneline(prefix, sha1, list);
 763                 free(prefix);
 764                 return ret;
 765         }
 766         return 0;
 767 }
 768
 769 static int get_describe_name(const char *name, int len, unsigned char *sha1)
 770 {
 771         const char *cp;
 772         unsigned flags = GET_SHA1_QUIETLY | GET_SHA1_COMMIT;
 773
 774         for (cp = name + len - 1; name + 2 <= cp; cp--) {
 775                 char ch = *cp;
 776                 if (!isxdigit(ch)) {
 777                         /* We must be looking at g in "SOMETHING-g"
 778                          * for it to be describe output.
 779                          */
 780                         if (ch == 'g' && cp[-1] == '-') {
 781                                 cp++;
 782                                 len -= cp - name;
 783                                 return get_short_sha1(cp, len, sha1, flags);
 784                         }
 785                 }
 786         }
 787         return -1;
 788 }
 789
 790 static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags)
 791 {
 792         int ret, has_suffix;
 793         const char *cp;
 794
 795         /*
 796          * "name~3" is "name^^^", "name~" is "name~1", and "name^" is "name^1".
 797          */
 798         has_suffix = 0;
 799         for (cp = name + len - 1; name <= cp; cp--) {
 800                 int ch = *cp;
 801                 if ('0' <= ch && ch <= '9')
 802                         continue;
 803                 if (ch == '~' || ch == '^')
 804                         has_suffix = ch;
 805                 break;
 806         }
 807
 808         if (has_suffix) {
 809                 int num = 0;
 810                 int len1 = cp - name;
 811                 cp++;
 812                 while (cp < name + len)
 813                         num = num * 10 + *cp++ - '0';
 814                 if (!num && len1 == len - 1)
 815                         num = 1;
 816                 if (has_suffix == '^')
 817                         return get_parent(name, len1, sha1, num);
 818                 /* else if (has_suffix == '~') -- goes without saying */
 819                 return get_nth_ancestor(name, len1, sha1, num);
 820         }
 821
 822         ret = peel_onion(name, len, sha1);
 823         if (!ret)
 824                 return 0;
 825
 826         ret = get_sha1_basic(name, len, sha1, lookup_flags);
 827         if (!ret)
 828                 return 0;
 829
 830         /* It could be describe output that is "SOMETHING-gXXXX" */
 831         ret = get_describe_name(name, len, sha1);
 832         if (!ret)
 833                 return 0;
 834
 835         return get_short_sha1(name, len, sha1, lookup_flags);
 836 }
 837
 838 /*
 839  * This interprets names like ':/Initial revision of "git"' by searching
 840  * through history and returning the first commit whose message starts
 841  * the given regular expression.
 842  *
 843  * For negative-matching, prefix the pattern-part with '!-', like: ':/!-WIP'.
 844  *
 845  * For a literal '!' character at the beginning of a pattern, you have to repeat
 846  * that, like: ':/!!foo'
 847  *
 848  * For future extension, all other sequences beginning with ':/!' are reserved.
 849  */
 850
 851 /* Remember to update object flag allocation in object.h */
 852 #define ONELINE_SEEN (1u<<20)
 853
 854 static int handle_one_ref(const char *path, const struct object_id *oid,
 855                           int flag, void *cb_data)
 856 {
 857         struct commit_list **list = cb_data;
 858         struct object *object = parse_object(oid->hash);
 859         if (!object)
 860                 return 0;
 861         if (object->type == OBJ_TAG) {
 862                 object = deref_tag(object, path, strlen(path));
 863                 if (!object)
 864                         return 0;
 865         }
 866         if (object->type != OBJ_COMMIT)
 867                 return 0;
 868         commit_list_insert((struct commit *)object, list);
 869         return 0;
 870 }
 871
 872 static int get_sha1_oneline(const char *prefix, unsigned char *sha1,
 873                             struct commit_list *list)
 874 {
 875         struct commit_list *backup = NULL, *l;
 876         int found = 0;
 877         int negative = 0;
 878         regex_t regex;
 879
 880         if (prefix[0] == '!') {
 881                 prefix++;
 882
 883                 if (prefix[0] == '-') {
 884                         prefix++;
 885                         negative = 1;
 886                 } else if (prefix[0] != '!') {
 887                         return -1;
 888                 }
 889         }
 890
 891         if (regcomp(&regex, prefix, REG_EXTENDED))
 892                 return -1;
 893
 894         for (l = list; l; l = l->next) {
 895                 l->item->object.flags |= ONELINE_SEEN;
 896                 commit_list_insert(l->item, &backup);
 897         }
 898         while (list) {
 899                 const char *p, *buf;
 900                 struct commit *commit;
 901                 int matches;
 902
 903                 commit = pop_most_recent_commit(&list, ONELINE_SEEN);
 904                 if (!parse_object(commit->object.oid.hash))
 905                         continue;
 906                 buf = get_commit_buffer(commit, NULL);
 907                 p = strstr(buf, "\n\n");
 908                 matches = negative ^ (p && !regexec(&regex, p + 2, 0, NULL, 0));
 909                 unuse_commit_buffer(commit, buf);
 910
 911                 if (matches) {
 912                         hashcpy(sha1, commit->object.oid.hash);
 913                         found = 1;
 914                         break;
 915                 }
 916         }
 917         regfree(&regex);
 918         free_commit_list(list);
 919         for (l = backup; l; l = l->next)
 920                 clear_commit_marks(l->item, ONELINE_SEEN);
 921         free_commit_list(backup);
 922         return found ? 0 : -1;
 923 }
 924
 925 struct grab_nth_branch_switch_cbdata {
 926         int remaining;
 927         struct strbuf buf;
 928 };
 929
 930 static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
 931                                   const char *email, unsigned long timestamp, int tz,
 932                                   const char *message, void *cb_data)
 933 {
 934         struct grab_nth_branch_switch_cbdata *cb = cb_data;
 935         const char *match = NULL, *target = NULL;
 936         size_t len;
 937
 938         if (skip_prefix(message, "checkout: moving from ", &match))
 939                 target = strstr(match, " to ");
 940
 941         if (!match || !target)
 942                 return 0;
 943         if (--(cb->remaining) == 0) {
 944                 len = target - match;
 945                 strbuf_reset(&cb->buf);
 946                 strbuf_add(&cb->buf, match, len);
 947                 return 1; /* we are done */
 948         }
 949         return 0;
 950 }
 951
 952 /*
 953  * Parse @{-N} syntax, return the number of characters parsed
 954  * if successful; otherwise signal an error with negative value.
 955  */
 956 static int interpret_nth_prior_checkout(const char *name, int namelen,
 957                                         struct strbuf *buf)
 958 {
 959         long nth;
 960         int retval;
 961         struct grab_nth_branch_switch_cbdata cb;
 962         const char *brace;
 963         char *num_end;
 964
 965         if (namelen < 4)
 966                 return -1;
 967         if (name[0] != '@' || name[1] != '{' || name[2] != '-')
 968                 return -1;
 969         brace = memchr(name, '}', namelen);
 970         if (!brace)
 971                 return -1;
 972         nth = strtol(name + 3, &num_end, 10);
 973         if (num_end != brace)
 974                 return -1;
 975         if (nth <= 0)
 976                 return -1;
 977         cb.remaining = nth;
 978         strbuf_init(&cb.buf, 20);
 979
 980         retval = 0;
 981         if (0 < for_each_reflog_ent_reverse("HEAD", grab_nth_branch_switch, &cb)) {
 982                 strbuf_reset(buf);
 983                 strbuf_addbuf(buf, &cb.buf);
 984                 retval = brace - name + 1;
 985         }
 986
 987         strbuf_release(&cb.buf);
 988         return retval;
 989 }
 990
 991 int get_oid_mb(const char *name, struct object_id *oid)
 992 {
 993         struct commit *one, *two;
 994         struct commit_list *mbs;
 995         struct object_id oid_tmp;
 996         const char *dots;
 997         int st;
 998
 999         dots = strstr(name, "...");
1000         if (!dots)
1001                 return get_oid(name, oid);
1002         if (dots == name)
1003                 st = get_oid("HEAD", &oid_tmp);
1004         else {
1005                 struct strbuf sb;
1006                 strbuf_init(&sb, dots - name);
1007                 strbuf_add(&sb, name, dots - name);
1008                 st = get_sha1_committish(sb.buf, oid_tmp.hash);
1009                 strbuf_release(&sb);
1010         }
1011         if (st)
1012                 return st;
1013         one = lookup_commit_reference_gently(oid_tmp.hash, 0);
1014         if (!one)
1015                 return -1;
1016
1017         if (get_sha1_committish(dots[3] ? (dots + 3) : "HEAD", oid_tmp.hash))
1018                 return -1;
1019         two = lookup_commit_reference_gently(oid_tmp.hash, 0);
1020         if (!two)
1021                 return -1;
1022         mbs = get_merge_bases(one, two);
1023         if (!mbs || mbs->next)
1024                 st = -1;
1025         else {
1026                 st = 0;
1027                 oidcpy(oid, &mbs->item->object.oid);
1028         }
1029         free_commit_list(mbs);
1030         return st;
1031 }
1032
1033 /* parse @something syntax, when 'something' is not {.*} */
1034 static int interpret_empty_at(const char *name, int namelen, int len, struct strbuf *buf)
1035 {
1036         const char *next;
1037
1038         if (len || name[1] == '{')
1039                 return -1;
1040
1041         /* make sure it's a single @, or @@{.*}, not @foo */
1042         next = memchr(name + len + 1, '@', namelen - len - 1);
1043         if (next && next[1] != '{')
1044                 return -1;
1045         if (!next)
1046                 next = name + namelen;
1047         if (next != name + 1)
1048                 return -1;
1049
1050         strbuf_reset(buf);
1051         strbuf_add(buf, "HEAD", 4);
1052         return 1;
1053 }
1054
1055 static int reinterpret(const char *name, int namelen, int len, struct strbuf *buf)
1056 {
1057         /* we have extra data, which might need further processing */
1058         struct strbuf tmp = STRBUF_INIT;
1059         int used = buf->len;
1060         int ret;
1061
1062         strbuf_add(buf, name + len, namelen - len);
1063         ret = interpret_branch_name(buf->buf, buf->len, &tmp);
1064         /* that data was not interpreted, remove our cruft */
1065         if (ret < 0) {
1066                 strbuf_setlen(buf, used);
1067                 return len;
1068         }
1069         strbuf_reset(buf);
1070         strbuf_addbuf(buf, &tmp);
1071         strbuf_release(&tmp);
1072         /* tweak for size of {-N} versus expanded ref name */
1073         return ret - used + len;
1074 }
1075
1076 static void set_shortened_ref(struct strbuf *buf, const char *ref)
1077 {
1078         char *s = shorten_unambiguous_ref(ref, 0);
1079         strbuf_reset(buf);
1080         strbuf_addstr(buf, s);
1081         free(s);
1082 }
1083
1084 static int interpret_branch_mark(const char *name, int namelen,
1085                                  int at, struct strbuf *buf,
1086                                  int (*get_mark)(const char *, int),
1087                                  const char *(*get_data)(struct branch *,
1088                                                          struct strbuf *))
1089 {
1090         int len;
1091         struct branch *branch;
1092         struct strbuf err = STRBUF_INIT;
1093         const char *value;
1094
1095         len = get_mark(name + at, namelen - at);
1096         if (!len)
1097                 return -1;
1098
1099         if (memchr(name, ':', at))
1100                 return -1;
1101
1102         if (at) {
1103                 char *name_str = xmemdupz(name, at);
1104                 branch = branch_get(name_str);
1105                 free(name_str);
1106         } else
1107                 branch = branch_get(NULL);
1108
1109         value = get_data(branch, &err);
1110         if (!value)
1111                 die("%s", err.buf);
1112
1113         set_shortened_ref(buf, value);
1114         return len + at;
1115 }
1116
1117 /*
1118  * This reads short-hand syntax that not only evaluates to a commit
1119  * object name, but also can act as if the end user spelled the name
1120  * of the branch from the command line.
1121  *
1122  * - "@{-N}" finds the name of the Nth previous branch we were on, and
1123  *   places the name of the branch in the given buf and returns the
1124  *   number of characters parsed if successful.
1125  *
1126  * - "<branch>@{upstream}" finds the name of the other ref that
1127  *   <branch> is configured to merge with (missing <branch> defaults
1128  *   to the current branch), and places the name of the branch in the
1129  *   given buf and returns the number of characters parsed if
1130  *   successful.
1131  *
1132  * If the input is not of the accepted format, it returns a negative
1133  * number to signal an error.
1134  *
1135  * If the input was ok but there are not N branch switches in the
1136  * reflog, it returns 0.
1137  */
1138 int interpret_branch_name(const char *name, int namelen, struct strbuf *buf)
1139 {
1140         char *at;
1141         const char *start;
1142         int len = interpret_nth_prior_checkout(name, namelen, buf);
1143
1144         if (!namelen)
1145                 namelen = strlen(name);
1146
1147         if (!len) {
1148                 return len; /* syntax Ok, not enough switches */
1149         } else if (len > 0) {
1150                 if (len == namelen)
1151                         return len; /* consumed all */
1152                 else
1153                         return reinterpret(name, namelen, len, buf);
1154         }
1155
1156         for (start = name;
1157              (at = memchr(start, '@', namelen - (start - name)));
1158              start = at + 1) {
1159
1160                 len = interpret_empty_at(name, namelen, at - name, buf);
1161                 if (len > 0)
1162                         return reinterpret(name, namelen, len, buf);
1163
1164                 len = interpret_branch_mark(name, namelen, at - name, buf,
1165                                             upstream_mark, branch_get_upstream);
1166                 if (len > 0)
1167                         return len;
1168
1169                 len = interpret_branch_mark(name, namelen, at - name, buf,
1170                                             push_mark, branch_get_push);
1171                 if (len > 0)
1172                         return len;
1173         }
1174
1175         return -1;
1176 }
1177
1178 int strbuf_branchname(struct strbuf *sb, const char *name)
1179 {
1180         int len = strlen(name);
1181         int used = interpret_branch_name(name, len, sb);
1182
1183         if (used == len)
1184                 return 0;
1185         if (used < 0)
1186                 used = 0;
1187         strbuf_add(sb, name + used, len - used);
1188         return len;
1189 }
1190
1191 int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
1192 {
1193         strbuf_branchname(sb, name);
1194         if (name[0] == '-')
1195                 return -1;
1196         strbuf_splice(sb, 0, 0, "refs/heads/", 11);
1197         return check_refname_format(sb->buf, 0);
1198 }
1199
1200 /*
1201  * This is like "get_sha1_basic()", except it allows "sha1 expressions",
1202  * notably "xyz^" for "parent of xyz"
1203  */
1204 int get_sha1(const char *name, unsigned char *sha1)
1205 {
1206         struct object_context unused;
1207         return get_sha1_with_context(name, 0, sha1, &unused);
1208 }
1209
1210 /*
1211  * This is like "get_sha1()", but for struct object_id.
1212  */
1213 int get_oid(const char *name, struct object_id *oid)
1214 {
1215         return get_sha1(name, oid->hash);
1216 }
1217
1218
1219 /*
1220  * Many callers know that the user meant to name a commit-ish by
1221  * syntactical positions where the object name appears.  Calling this
1222  * function allows the machinery to disambiguate shorter-than-unique
1223  * abbreviated object names between commit-ish and others.
1224  *
1225  * Note that this does NOT error out when the named object is not a
1226  * commit-ish. It is merely to give a hint to the disambiguation
1227  * machinery.
1228  */
1229 int get_sha1_committish(const char *name, unsigned char *sha1)
1230 {
1231         struct object_context unused;
1232         return get_sha1_with_context(name, GET_SHA1_COMMITTISH,
1233                                      sha1, &unused);
1234 }
1235
1236 int get_sha1_treeish(const char *name, unsigned char *sha1)
1237 {
1238         struct object_context unused;
1239         return get_sha1_with_context(name, GET_SHA1_TREEISH,
1240                                      sha1, &unused);
1241 }
1242
1243 int get_sha1_commit(const char *name, unsigned char *sha1)
1244 {
1245         struct object_context unused;
1246         return get_sha1_with_context(name, GET_SHA1_COMMIT,
1247                                      sha1, &unused);
1248 }
1249
1250 int get_sha1_tree(const char *name, unsigned char *sha1)
1251 {
1252         struct object_context unused;
1253         return get_sha1_with_context(name, GET_SHA1_TREE,
1254                                      sha1, &unused);
1255 }
1256
1257 int get_sha1_blob(const char *name, unsigned char *sha1)
1258 {
1259         struct object_context unused;
1260         return get_sha1_with_context(name, GET_SHA1_BLOB,
1261                                      sha1, &unused);
1262 }
1263
1264 /* Must be called only when object_name:filename doesn't exist. */
1265 static void diagnose_invalid_sha1_path(const char *prefix,
1266                                        const char *filename,
1267                                        const unsigned char *tree_sha1,
1268                                        const char *object_name,
1269                                        int object_name_len)
1270 {
1271         unsigned char sha1[20];
1272         unsigned mode;
1273
1274         if (!prefix)
1275                 prefix = "";
1276
1277         if (file_exists(filename))
1278                 die("Path '%s' exists on disk, but not in '%.*s'.",
1279                     filename, object_name_len, object_name);
1280         if (errno == ENOENT || errno == ENOTDIR) {
1281                 char *fullname = xstrfmt("%s%s", prefix, filename);
1282
1283                 if (!get_tree_entry(tree_sha1, fullname,
1284                                     sha1, &mode)) {
1285                         die("Path '%s' exists, but not '%s'.\n"
1286                             "Did you mean '%.*s:%s' aka '%.*s:./%s'?",
1287                             fullname,
1288                             filename,
1289                             object_name_len, object_name,
1290                             fullname,
1291                             object_name_len, object_name,
1292                             filename);
1293                 }
1294                 die("Path '%s' does not exist in '%.*s'",
1295                     filename, object_name_len, object_name);
1296         }
1297 }
1298
1299 /* Must be called only when :stage:filename doesn't exist. */
1300 static void diagnose_invalid_index_path(int stage,
1301                                         const char *prefix,
1302                                         const char *filename)
1303 {
1304         const struct cache_entry *ce;
1305         int pos;
1306         unsigned namelen = strlen(filename);
1307         struct strbuf fullname = STRBUF_INIT;
1308
1309         if (!prefix)
1310                 prefix = "";
1311
1312         /* Wrong stage number? */
1313         pos = cache_name_pos(filename, namelen);
1314         if (pos < 0)
1315                 pos = -pos - 1;
1316         if (pos < active_nr) {
1317                 ce = active_cache[pos];
1318                 if (ce_namelen(ce) == namelen &&
1319                     !memcmp(ce->name, filename, namelen))
1320                         die("Path '%s' is in the index, but not at stage %d.\n"
1321                             "Did you mean ':%d:%s'?",
1322                             filename, stage,
1323                             ce_stage(ce), filename);
1324         }
1325
1326         /* Confusion between relative and absolute filenames? */
1327         strbuf_addstr(&fullname, prefix);
1328         strbuf_addstr(&fullname, filename);
1329         pos = cache_name_pos(fullname.buf, fullname.len);
1330         if (pos < 0)
1331                 pos = -pos - 1;
1332         if (pos < active_nr) {
1333                 ce = active_cache[pos];
1334                 if (ce_namelen(ce) == fullname.len &&
1335                     !memcmp(ce->name, fullname.buf, fullname.len))
1336                         die("Path '%s' is in the index, but not '%s'.\n"
1337                             "Did you mean ':%d:%s' aka ':%d:./%s'?",
1338                             fullname.buf, filename,
1339                             ce_stage(ce), fullname.buf,
1340                             ce_stage(ce), filename);
1341         }
1342
1343         if (file_exists(filename))
1344                 die("Path '%s' exists on disk, but not in the index.", filename);
1345         if (errno == ENOENT || errno == ENOTDIR)
1346                 die("Path '%s' does not exist (neither on disk nor in the index).",
1347                     filename);
1348
1349         strbuf_release(&fullname);
1350 }
1351
1352
1353 static char *resolve_relative_path(const char *rel)
1354 {
1355         if (!starts_with(rel, "./") && !starts_with(rel, "../"))
1356                 return NULL;
1357
1358         if (!is_inside_work_tree())
1359                 die("relative path syntax can't be used outside working tree.");
1360
1361         /* die() inside prefix_path() if resolved path is outside worktree */
1362         return prefix_path(startup_info->prefix,
1363                            startup_info->prefix ? strlen(startup_info->prefix) : 0,
1364                            rel);
1365 }
1366
1367 static int get_sha1_with_context_1(const char *name,
1368                                    unsigned flags,
1369                                    const char *prefix,
1370                                    unsigned char *sha1,
1371                                    struct object_context *oc)
1372 {
1373         int ret, bracket_depth;
1374         int namelen = strlen(name);
1375         const char *cp;
1376         int only_to_die = flags & GET_SHA1_ONLY_TO_DIE;
1377
1378         memset(oc, 0, sizeof(*oc));
1379         oc->mode = S_IFINVALID;
1380         ret = get_sha1_1(name, namelen, sha1, flags);
1381         if (!ret)
1382                 return ret;
1383         /*
1384          * sha1:path --> object name of path in ent sha1
1385          * :path -> object name of absolute path in index
1386          * :./path -> object name of path relative to cwd in index
1387          * :[0-3]:path -> object name of path in index at stage
1388          * :/foo -> recent commit matching foo
1389          */
1390         if (name[0] == ':') {
1391                 int stage = 0;
1392                 const struct cache_entry *ce;
1393                 char *new_path = NULL;
1394                 int pos;
1395                 if (!only_to_die && namelen > 2 && name[1] == '/') {
1396                         struct commit_list *list = NULL;
1397
1398                         for_each_ref(handle_one_ref, &list);
1399                         commit_list_sort_by_date(&list);
1400                         return get_sha1_oneline(name + 2, sha1, list);
1401                 }
1402                 if (namelen < 3 ||
1403                     name[2] != ':' ||
1404                     name[1] < '0' || '3' < name[1])
1405                         cp = name + 1;
1406                 else {
1407                         stage = name[1] - '0';
1408                         cp = name + 3;
1409                 }
1410                 new_path = resolve_relative_path(cp);
1411                 if (!new_path) {
1412                         namelen = namelen - (cp - name);
1413                 } else {
1414                         cp = new_path;
1415                         namelen = strlen(cp);
1416                 }
1417
1418                 strlcpy(oc->path, cp, sizeof(oc->path));
1419
1420                 if (!active_cache)
1421                         read_cache();
1422                 pos = cache_name_pos(cp, namelen);
1423                 if (pos < 0)
1424                         pos = -pos - 1;
1425                 while (pos < active_nr) {
1426                         ce = active_cache[pos];
1427                         if (ce_namelen(ce) != namelen ||
1428                             memcmp(ce->name, cp, namelen))
1429                                 break;
1430                         if (ce_stage(ce) == stage) {
1431                                 hashcpy(sha1, ce->oid.hash);
1432                                 oc->mode = ce->ce_mode;
1433                                 free(new_path);
1434                                 return 0;
1435                         }
1436                         pos++;
1437                 }
1438                 if (only_to_die && name[1] && name[1] != '/')
1439                         diagnose_invalid_index_path(stage, prefix, cp);
1440                 free(new_path);
1441                 return -1;
1442         }
1443         for (cp = name, bracket_depth = 0; *cp; cp++) {
1444                 if (*cp == '{')
1445                         bracket_depth++;
1446                 else if (bracket_depth && *cp == '}')
1447                         bracket_depth--;
1448                 else if (!bracket_depth && *cp == ':')
1449                         break;
1450         }
1451         if (*cp == ':') {
1452                 unsigned char tree_sha1[20];
1453                 int len = cp - name;
1454                 if (!get_sha1_1(name, len, tree_sha1, GET_SHA1_TREEISH)) {
1455                         const char *filename = cp+1;
1456                         char *new_filename = NULL;
1457
1458                         new_filename = resolve_relative_path(filename);
1459                         if (new_filename)
1460                                 filename = new_filename;
1461                         if (flags & GET_SHA1_FOLLOW_SYMLINKS) {
1462                                 ret = get_tree_entry_follow_symlinks(tree_sha1,
1463                                         filename, sha1, &oc->symlink_path,
1464                                         &oc->mode);
1465                         } else {
1466                                 ret = get_tree_entry(tree_sha1, filename,
1467                                                      sha1, &oc->mode);
1468                                 if (ret && only_to_die) {
1469                                         diagnose_invalid_sha1_path(prefix,
1470                                                                    filename,
1471                                                                    tree_sha1,
1472                                                                    name, len);
1473                                 }
1474                         }
1475                         hashcpy(oc->tree, tree_sha1);
1476                         strlcpy(oc->path, filename, sizeof(oc->path));
1477
1478                         free(new_filename);
1479                         return ret;
1480                 } else {
1481                         if (only_to_die)
1482                                 die("Invalid object name '%.*s'.", len, name);
1483                 }
1484         }
1485         return ret;
1486 }
1487
1488 /*
1489  * Call this function when you know "name" given by the end user must
1490  * name an object but it doesn't; the function _may_ die with a better
1491  * diagnostic message than "no such object 'name'", e.g. "Path 'doc' does not
1492  * exist in 'HEAD'" when given "HEAD:doc", or it may return in which case
1493  * you have a chance to diagnose the error further.
1494  */
1495 void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
1496 {
1497         struct object_context oc;
1498         unsigned char sha1[20];
1499         get_sha1_with_context_1(name, GET_SHA1_ONLY_TO_DIE, prefix, sha1, &oc);
1500 }
1501
1502 int get_sha1_with_context(const char *str, unsigned flags, unsigned char *sha1, struct object_context *orc)
1503 {
1504         if (flags & GET_SHA1_FOLLOW_SYMLINKS && flags & GET_SHA1_ONLY_TO_DIE)
1505                 die("BUG: incompatible flags for get_sha1_with_context");
1506         return get_sha1_with_context_1(str, flags, NULL, sha1, orc);
1507 }