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         int len; /* length of prefix in hex chars */
  17         char hex_pfx[GIT_SHA1_HEXSZ + 1];
  18         unsigned char bin_pfx[GIT_SHA1_RAWSZ];
  19
  20         disambiguate_hint_fn fn;
  21         void *cb_data;
  22         unsigned char candidate[GIT_SHA1_RAWSZ];
  23         unsigned candidate_exists:1;
  24         unsigned candidate_checked:1;
  25         unsigned candidate_ok:1;
  26         unsigned disambiguate_fn_used:1;
  27         unsigned ambiguous:1;
  28         unsigned always_call_fn:1;
  29 };
  30
  31 static void update_candidates(struct disambiguate_state *ds, const unsigned char *current)
  32 {
  33         if (ds->always_call_fn) {
  34                 ds->ambiguous = ds->fn(current, ds->cb_data) ? 1 : 0;
  35                 return;
  36         }
  37         if (!ds->candidate_exists) {
  38                 /* this is the first candidate */
  39                 hashcpy(ds->candidate, current);
  40                 ds->candidate_exists = 1;
  41                 return;
  42         } else if (!hashcmp(ds->candidate, current)) {
  43                 /* the same as what we already have seen */
  44                 return;
  45         }
  46
  47         if (!ds->fn) {
  48                 /* cannot disambiguate between ds->candidate and current */
  49                 ds->ambiguous = 1;
  50                 return;
  51         }
  52
  53         if (!ds->candidate_checked) {
  54                 ds->candidate_ok = ds->fn(ds->candidate, ds->cb_data);
  55                 ds->disambiguate_fn_used = 1;
  56                 ds->candidate_checked = 1;
  57         }
  58
  59         if (!ds->candidate_ok) {
  60                 /* discard the candidate; we know it does not satisfy fn */
  61                 hashcpy(ds->candidate, current);
  62                 ds->candidate_checked = 0;
  63                 return;
  64         }
  65
  66         /* if we reach this point, we know ds->candidate satisfies fn */
  67         if (ds->fn(current, ds->cb_data)) {
  68                 /*
  69                  * if both current and candidate satisfy fn, we cannot
  70                  * disambiguate.
  71                  */
  72                 ds->candidate_ok = 0;
  73                 ds->ambiguous = 1;
  74         }
  75
  76         /* otherwise, current can be discarded and candidate is still good */
  77 }
  78
  79 static void find_short_object_filename(struct disambiguate_state *ds)
  80 {
  81         struct alternate_object_database *alt;
  82         char hex[GIT_SHA1_HEXSZ];
  83         static struct alternate_object_database *fakeent;
  84
  85         if (!fakeent) {
  86                 /*
  87                  * Create a "fake" alternate object database that
  88                  * points to our own object database, to make it
  89                  * easier to get a temporary working space in
  90                  * alt->name/alt->base while iterating over the
  91                  * object databases including our own.
  92                  */
  93                 const char *objdir = get_object_directory();
  94                 size_t objdir_len = strlen(objdir);
  95                 fakeent = xmalloc(st_add3(sizeof(*fakeent), objdir_len, 43));
  96                 memcpy(fakeent->base, objdir, objdir_len);
  97                 fakeent->name = fakeent->base + objdir_len + 1;
  98                 fakeent->name[-1] = '/';
  99         }
 100         fakeent->next = alt_odb_list;
 101
 102         xsnprintf(hex, sizeof(hex), "%.2s", ds->hex_pfx);
 103         for (alt = fakeent; alt && !ds->ambiguous; alt = alt->next) {
 104                 struct dirent *de;
 105                 DIR *dir;
 106                 /*
 107                  * every alt_odb struct has 42 extra bytes after the base
 108                  * for exactly this purpose
 109                  */
 110                 xsnprintf(alt->name, 42, "%.2s/", ds->hex_pfx);
 111                 dir = opendir(alt->base);
 112                 if (!dir)
 113                         continue;
 114
 115                 while (!ds->ambiguous && (de = readdir(dir)) != NULL) {
 116                         unsigned char sha1[20];
 117
 118                         if (strlen(de->d_name) != 38)
 119                                 continue;
 120                         if (memcmp(de->d_name, ds->hex_pfx + 2, ds->len - 2))
 121                                 continue;
 122                         memcpy(hex + 2, de->d_name, 38);
 123                         if (!get_sha1_hex(hex, sha1))
 124                                 update_candidates(ds, sha1);
 125                 }
 126                 closedir(dir);
 127         }
 128 }
 129
 130 static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
 131 {
 132         do {
 133                 if (*a != *b)
 134                         return 0;
 135                 a++;
 136                 b++;
 137                 len -= 2;
 138         } while (len > 1);
 139         if (len)
 140                 if ((*a ^ *b) & 0xf0)
 141                         return 0;
 142         return 1;
 143 }
 144
 145 static void unique_in_pack(struct packed_git *p,
 146                            struct disambiguate_state *ds)
 147 {
 148         uint32_t num, last, i, first = 0;
 149         const unsigned char *current = NULL;
 150
 151         open_pack_index(p);
 152         num = p->num_objects;
 153         last = num;
 154         while (first < last) {
 155                 uint32_t mid = (first + last) / 2;
 156                 const unsigned char *current;
 157                 int cmp;
 158
 159                 current = nth_packed_object_sha1(p, mid);
 160                 cmp = hashcmp(ds->bin_pfx, current);
 161                 if (!cmp) {
 162                         first = mid;
 163                         break;
 164                 }
 165                 if (cmp > 0) {
 166                         first = mid+1;
 167                         continue;
 168                 }
 169                 last = mid;
 170         }
 171
 172         /*
 173          * At this point, "first" is the location of the lowest object
 174          * with an object name that could match "bin_pfx".  See if we have
 175          * 0, 1 or more objects that actually match(es).
 176          */
 177         for (i = first; i < num && !ds->ambiguous; i++) {
 178                 current = nth_packed_object_sha1(p, i);
 179                 if (!match_sha(ds->len, ds->bin_pfx, current))
 180                         break;
 181                 update_candidates(ds, current);
 182         }
 183 }
 184
 185 static void find_short_packed_object(struct disambiguate_state *ds)
 186 {
 187         struct packed_git *p;
 188
 189         prepare_packed_git();
 190         for (p = packed_git; p && !ds->ambiguous; p = p->next)
 191                 unique_in_pack(p, ds);
 192 }
 193
 194 #define SHORT_NAME_NOT_FOUND (-1)
 195 #define SHORT_NAME_AMBIGUOUS (-2)
 196
 197 static int finish_object_disambiguation(struct disambiguate_state *ds,
 198                                         unsigned char *sha1)
 199 {
 200         if (ds->ambiguous)
 201                 return SHORT_NAME_AMBIGUOUS;
 202
 203         if (!ds->candidate_exists)
 204                 return SHORT_NAME_NOT_FOUND;
 205
 206         if (!ds->candidate_checked)
 207                 /*
 208                  * If this is the only candidate, there is no point
 209                  * calling the disambiguation hint callback.
 210                  *
 211                  * On the other hand, if the current candidate
 212                  * replaced an earlier candidate that did _not_ pass
 213                  * the disambiguation hint callback, then we do have
 214                  * more than one objects that match the short name
 215                  * given, so we should make sure this one matches;
 216                  * otherwise, if we discovered this one and the one
 217                  * that we previously discarded in the reverse order,
 218                  * we would end up showing different results in the
 219                  * same repository!
 220                  */
 221                 ds->candidate_ok = (!ds->disambiguate_fn_used ||
 222                                     ds->fn(ds->candidate, ds->cb_data));
 223
 224         if (!ds->candidate_ok)
 225                 return SHORT_NAME_AMBIGUOUS;
 226
 227         hashcpy(sha1, ds->candidate);
 228         return 0;
 229 }
 230
 231 static int disambiguate_commit_only(const unsigned char *sha1, void *cb_data_unused)
 232 {
 233         int kind = sha1_object_info(sha1, NULL);
 234         return kind == OBJ_COMMIT;
 235 }
 236
 237 static int disambiguate_committish_only(const unsigned char *sha1, void *cb_data_unused)
 238 {
 239         struct object *obj;
 240         int kind;
 241
 242         kind = sha1_object_info(sha1, NULL);
 243         if (kind == OBJ_COMMIT)
 244                 return 1;
 245         if (kind != OBJ_TAG)
 246                 return 0;
 247
 248         /* We need to do this the hard way... */
 249         obj = deref_tag(parse_object(sha1), NULL, 0);
 250         if (obj && obj->type == OBJ_COMMIT)
 251                 return 1;
 252         return 0;
 253 }
 254
 255 static int disambiguate_tree_only(const unsigned char *sha1, void *cb_data_unused)
 256 {
 257         int kind = sha1_object_info(sha1, NULL);
 258         return kind == OBJ_TREE;
 259 }
 260
 261 static int disambiguate_treeish_only(const unsigned char *sha1, void *cb_data_unused)
 262 {
 263         struct object *obj;
 264         int kind;
 265
 266         kind = sha1_object_info(sha1, NULL);
 267         if (kind == OBJ_TREE || kind == OBJ_COMMIT)
 268                 return 1;
 269         if (kind != OBJ_TAG)
 270                 return 0;
 271
 272         /* We need to do this the hard way... */
 273         obj = deref_tag(parse_object(sha1), NULL, 0);
 274         if (obj && (obj->type == OBJ_TREE || obj->type == OBJ_COMMIT))
 275                 return 1;
 276         return 0;
 277 }
 278
 279 static int disambiguate_blob_only(const unsigned char *sha1, void *cb_data_unused)
 280 {
 281         int kind = sha1_object_info(sha1, NULL);
 282         return kind == OBJ_BLOB;
 283 }
 284
 285 static int init_object_disambiguation(const char *name, int len,
 286                                       struct disambiguate_state *ds)
 287 {
 288         int i;
 289
 290         if (len < MINIMUM_ABBREV || len > GIT_SHA1_HEXSZ)
 291                 return -1;
 292
 293         memset(ds, 0, sizeof(*ds));
 294
 295         for (i = 0; i < len ;i++) {
 296                 unsigned char c = name[i];
 297                 unsigned char val;
 298                 if (c >= '0' && c <= '9')
 299                         val = c - '0';
 300                 else if (c >= 'a' && c <= 'f')
 301                         val = c - 'a' + 10;
 302                 else if (c >= 'A' && c <='F') {
 303                         val = c - 'A' + 10;
 304                         c -= 'A' - 'a';
 305                 }
 306                 else
 307                         return -1;
 308                 ds->hex_pfx[i] = c;
 309                 if (!(i & 1))
 310                         val <<= 4;
 311                 ds->bin_pfx[i >> 1] |= val;
 312         }
 313
 314         ds->len = len;
 315         ds->hex_pfx[len] = '\0';
 316         prepare_alt_odb();
 317         return 0;
 318 }
 319
 320 static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 321                           unsigned flags)
 322 {
 323         int status;
 324         struct disambiguate_state ds;
 325         int quietly = !!(flags & GET_SHA1_QUIETLY);
 326
 327         if (init_object_disambiguation(name, len, &ds) < 0)
 328                 return -1;
 329
 330         if (HAS_MULTI_BITS(flags & GET_SHA1_DISAMBIGUATORS))
 331                 die("BUG: multiple get_short_sha1 disambiguator flags");
 332
 333         if (flags & GET_SHA1_COMMIT)
 334                 ds.fn = disambiguate_commit_only;
 335         else if (flags & GET_SHA1_COMMITTISH)
 336                 ds.fn = disambiguate_committish_only;
 337         else if (flags & GET_SHA1_TREE)
 338                 ds.fn = disambiguate_tree_only;
 339         else if (flags & GET_SHA1_TREEISH)
 340                 ds.fn = disambiguate_treeish_only;
 341         else if (flags & GET_SHA1_BLOB)
 342                 ds.fn = disambiguate_blob_only;
 343
 344         find_short_object_filename(&ds);
 345         find_short_packed_object(&ds);
 346         status = finish_object_disambiguation(&ds, sha1);
 347
 348         if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
 349                 return error(_("short SHA1 %s is ambiguous"), ds.hex_pfx);
 350         return status;
 351 }
 352
 353 int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
 354 {
 355         struct disambiguate_state ds;
 356
 357         if (init_object_disambiguation(prefix, strlen(prefix), &ds) < 0)
 358                 return -1;
 359
 360         ds.always_call_fn = 1;
 361         ds.cb_data = cb_data;
 362         ds.fn = fn;
 363
 364         find_short_object_filename(&ds);
 365         find_short_packed_object(&ds);
 366         return ds.ambiguous;
 367 }
 368
 369 int find_unique_abbrev_r(char *hex, const unsigned char *sha1, int len)
 370 {
 371         int status, exists;
 372
 373         sha1_to_hex_r(hex, sha1);
 374         if (len == 40 || !len)
 375                 return 40;
 376         exists = has_sha1_file(sha1);
 377         while (len < 40) {
 378                 unsigned char sha1_ret[20];
 379                 status = get_short_sha1(hex, len, sha1_ret, GET_SHA1_QUIETLY);
 380                 if (exists
 381                     ? !status
 382                     : status == SHORT_NAME_NOT_FOUND) {
 383                         hex[len] = 0;
 384                         return len;
 385                 }
 386                 len++;
 387         }
 388         return len;
 389 }
 390
 391 const char *find_unique_abbrev(const unsigned char *sha1, int len)
 392 {
 393         static char hex[GIT_SHA1_HEXSZ + 1];
 394         find_unique_abbrev_r(hex, sha1, len);
 395         return hex;
 396 }
 397
 398 static int ambiguous_path(const char *path, int len)
 399 {
 400         int slash = 1;
 401         int cnt;
 402
 403         for (cnt = 0; cnt < len; cnt++) {
 404                 switch (*path++) {
 405                 case '\0':
 406                         break;
 407                 case '/':
 408                         if (slash)
 409                                 break;
 410                         slash = 1;
 411                         continue;
 412                 case '.':
 413                         continue;
 414                 default:
 415                         slash = 0;
 416                         continue;
 417                 }
 418                 break;
 419         }
 420         return slash;
 421 }
 422
 423 static inline int at_mark(const char *string, int len,
 424                           const char **suffix, int nr)
 425 {
 426         int i;
 427
 428         for (i = 0; i < nr; i++) {
 429                 int suffix_len = strlen(suffix[i]);
 430                 if (suffix_len <= len
 431                     && !memcmp(string, suffix[i], suffix_len))
 432                         return suffix_len;
 433         }
 434         return 0;
 435 }
 436
 437 static inline int upstream_mark(const char *string, int len)
 438 {
 439         const char *suffix[] = { "@{upstream}", "@{u}" };
 440         return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
 441 }
 442
 443 static inline int push_mark(const char *string, int len)
 444 {
 445         const char *suffix[] = { "@{push}" };
 446         return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
 447 }
 448
 449 static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags);
 450 static int interpret_nth_prior_checkout(const char *name, int namelen, struct strbuf *buf);
 451
 452 static int get_sha1_basic(const char *str, int len, unsigned char *sha1,
 453                           unsigned int flags)
 454 {
 455         static const char *warn_msg = "refname '%.*s' is ambiguous.";
 456         static const char *object_name_msg = N_(
 457         "Git normally never creates a ref that ends with 40 hex characters\n"
 458         "because it will be ignored when you just specify 40-hex. These refs\n"
 459         "may be created by mistake. For example,\n"
 460         "\n"
 461         "  git checkout -b $br $(git rev-parse ...)\n"
 462         "\n"
 463         "where \"$br\" is somehow empty and a 40-hex ref is created. Please\n"
 464         "examine these refs and maybe delete them. Turn this message off by\n"
 465         "running \"git config advice.objectNameWarning false\"");
 466         unsigned char tmp_sha1[20];
 467         char *real_ref = NULL;
 468         int refs_found = 0;
 469         int at, reflog_len, nth_prior = 0;
 470
 471         if (len == 40 && !get_sha1_hex(str, sha1)) {
 472                 if (warn_ambiguous_refs && warn_on_object_refname_ambiguity) {
 473                         refs_found = dwim_ref(str, len, tmp_sha1, &real_ref);
 474                         if (refs_found > 0) {
 475                                 warning(warn_msg, len, str);
 476                                 if (advice_object_name_warning)
 477                                         fprintf(stderr, "%s\n", _(object_name_msg));
 478                         }
 479                         free(real_ref);
 480                 }
 481                 return 0;
 482         }
 483
 484         /* basic@{time or number or -number} format to query ref-log */
 485         reflog_len = at = 0;
 486         if (len && str[len-1] == '}') {
 487                 for (at = len-4; at >= 0; at--) {
 488                         if (str[at] == '@' && str[at+1] == '{') {
 489                                 if (str[at+2] == '-') {
 490                                         if (at != 0)
 491                                                 /* @{-N} not at start */
 492                                                 return -1;
 493                                         nth_prior = 1;
 494                                         continue;
 495                                 }
 496                                 if (!upstream_mark(str + at, len - at) &&
 497                                     !push_mark(str + at, len - at)) {
 498                                         reflog_len = (len-1) - (at+2);
 499                                         len = at;
 500                                 }
 501                                 break;
 502                         }
 503                 }
 504         }
 505
 506         /* Accept only unambiguous ref paths. */
 507         if (len && ambiguous_path(str, len))
 508                 return -1;
 509
 510         if (nth_prior) {
 511                 struct strbuf buf = STRBUF_INIT;
 512                 int detached;
 513
 514                 if (interpret_nth_prior_checkout(str, len, &buf) > 0) {
 515                         detached = (buf.len == 40 && !get_sha1_hex(buf.buf, sha1));
 516                         strbuf_release(&buf);
 517                         if (detached)
 518                                 return 0;
 519                 }
 520         }
 521
 522         if (!len && reflog_len)
 523                 /* allow "@{...}" to mean the current branch reflog */
 524                 refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
 525         else if (reflog_len)
 526                 refs_found = dwim_log(str, len, sha1, &real_ref);
 527         else
 528                 refs_found = dwim_ref(str, len, sha1, &real_ref);
 529
 530         if (!refs_found)
 531                 return -1;
 532
 533         if (warn_ambiguous_refs && !(flags & GET_SHA1_QUIETLY) &&
 534             (refs_found > 1 ||
 535              !get_short_sha1(str, len, tmp_sha1, GET_SHA1_QUIETLY)))
 536                 warning(warn_msg, len, str);
 537
 538         if (reflog_len) {
 539                 int nth, i;
 540                 unsigned long at_time;
 541                 unsigned long co_time;
 542                 int co_tz, co_cnt;
 543
 544                 /* Is it asking for N-th entry, or approxidate? */
 545                 for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 546                         char ch = str[at+2+i];
 547                         if ('0' <= ch && ch <= '9')
 548                                 nth = nth * 10 + ch - '0';
 549                         else
 550                                 nth = -1;
 551                 }
 552                 if (100000000 <= nth) {
 553                         at_time = nth;
 554                         nth = -1;
 555                 } else if (0 <= nth)
 556                         at_time = 0;
 557                 else {
 558                         int errors = 0;
 559                         char *tmp = xstrndup(str + at + 2, reflog_len);
 560                         at_time = approxidate_careful(tmp, &errors);
 561                         free(tmp);
 562                         if (errors) {
 563                                 free(real_ref);
 564                                 return -1;
 565                         }
 566                 }
 567                 if (read_ref_at(real_ref, flags, at_time, nth, sha1, NULL,
 568                                 &co_time, &co_tz, &co_cnt)) {
 569                         if (!len) {
 570                                 if (starts_with(real_ref, "refs/heads/")) {
 571                                         str = real_ref + 11;
 572                                         len = strlen(real_ref + 11);
 573                                 } else {
 574                                         /* detached HEAD */
 575                                         str = "HEAD";
 576                                         len = 4;
 577                                 }
 578                         }
 579                         if (at_time) {
 580                                 if (!(flags & GET_SHA1_QUIETLY)) {
 581                                         warning("Log for '%.*s' only goes "
 582                                                 "back to %s.", len, str,
 583                                                 show_date(co_time, co_tz, DATE_MODE(RFC2822)));
 584                                 }
 585                         } else {
 586                                 if (flags & GET_SHA1_QUIETLY) {
 587                                         exit(128);
 588                                 }
 589                                 die("Log for '%.*s' only has %d entries.",
 590                                     len, str, co_cnt);
 591                         }
 592                 }
 593         }
 594
 595         free(real_ref);
 596         return 0;
 597 }
 598
 599 static int get_parent(const char *name, int len,
 600                       unsigned char *result, int idx)
 601 {
 602         unsigned char sha1[20];
 603         int ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 604         struct commit *commit;
 605         struct commit_list *p;
 606
 607         if (ret)
 608                 return ret;
 609         commit = lookup_commit_reference(sha1);
 610         if (parse_commit(commit))
 611                 return -1;
 612         if (!idx) {
 613                 hashcpy(result, commit->object.oid.hash);
 614                 return 0;
 615         }
 616         p = commit->parents;
 617         while (p) {
 618                 if (!--idx) {
 619                         hashcpy(result, p->item->object.oid.hash);
 620                         return 0;
 621                 }
 622                 p = p->next;
 623         }
 624         return -1;
 625 }
 626
 627 static int get_nth_ancestor(const char *name, int len,
 628                             unsigned char *result, int generation)
 629 {
 630         unsigned char sha1[20];
 631         struct commit *commit;
 632         int ret;
 633
 634         ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 635         if (ret)
 636                 return ret;
 637         commit = lookup_commit_reference(sha1);
 638         if (!commit)
 639                 return -1;
 640
 641         while (generation--) {
 642                 if (parse_commit(commit) || !commit->parents)
 643                         return -1;
 644                 commit = commit->parents->item;
 645         }
 646         hashcpy(result, commit->object.oid.hash);
 647         return 0;
 648 }
 649
 650 struct object *peel_to_type(const char *name, int namelen,
 651                             struct object *o, enum object_type expected_type)
 652 {
 653         if (name && !namelen)
 654                 namelen = strlen(name);
 655         while (1) {
 656                 if (!o || (!o->parsed && !parse_object(o->oid.hash)))
 657                         return NULL;
 658                 if (expected_type == OBJ_ANY || o->type == expected_type)
 659                         return o;
 660                 if (o->type == OBJ_TAG)
 661                         o = ((struct tag*) o)->tagged;
 662                 else if (o->type == OBJ_COMMIT)
 663                         o = &(((struct commit *) o)->tree->object);
 664                 else {
 665                         if (name)
 666                                 error("%.*s: expected %s type, but the object "
 667                                       "dereferences to %s type",
 668                                       namelen, name, typename(expected_type),
 669                                       typename(o->type));
 670                         return NULL;
 671                 }
 672         }
 673 }
 674
 675 static int peel_onion(const char *name, int len, unsigned char *sha1,
 676                       unsigned lookup_flags)
 677 {
 678         unsigned char outer[20];
 679         const char *sp;
 680         unsigned int expected_type = 0;
 681         struct object *o;
 682
 683         /*
 684          * "ref^{type}" dereferences ref repeatedly until you cannot
 685          * dereference anymore, or you get an object of given type,
 686          * whichever comes first.  "ref^{}" means just dereference
 687          * tags until you get a non-tag.  "ref^0" is a shorthand for
 688          * "ref^{commit}".  "commit^{tree}" could be used to find the
 689          * top-level tree of the given commit.
 690          */
 691         if (len < 4 || name[len-1] != '}')
 692                 return -1;
 693
 694         for (sp = name + len - 1; name <= sp; sp--) {
 695                 int ch = *sp;
 696                 if (ch == '{' && name < sp && sp[-1] == '^')
 697                         break;
 698         }
 699         if (sp <= name)
 700                 return -1;
 701
 702         sp++; /* beginning of type name, or closing brace for empty */
 703         if (starts_with(sp, "commit}"))
 704                 expected_type = OBJ_COMMIT;
 705         else if (starts_with(sp, "tag}"))
 706                 expected_type = OBJ_TAG;
 707         else if (starts_with(sp, "tree}"))
 708                 expected_type = OBJ_TREE;
 709         else if (starts_with(sp, "blob}"))
 710                 expected_type = OBJ_BLOB;
 711         else if (starts_with(sp, "object}"))
 712                 expected_type = OBJ_ANY;
 713         else if (sp[0] == '}')
 714                 expected_type = OBJ_NONE;
 715         else if (sp[0] == '/')
 716                 expected_type = OBJ_COMMIT;
 717         else
 718                 return -1;
 719
 720         lookup_flags &= ~GET_SHA1_DISAMBIGUATORS;
 721         if (expected_type == OBJ_COMMIT)
 722                 lookup_flags |= GET_SHA1_COMMITTISH;
 723         else if (expected_type == OBJ_TREE)
 724                 lookup_flags |= GET_SHA1_TREEISH;
 725
 726         if (get_sha1_1(name, sp - name - 2, outer, lookup_flags))
 727                 return -1;
 728
 729         o = parse_object(outer);
 730         if (!o)
 731                 return -1;
 732         if (!expected_type) {
 733                 o = deref_tag(o, name, sp - name - 2);
 734                 if (!o || (!o->parsed && !parse_object(o->oid.hash)))
 735                         return -1;
 736                 hashcpy(sha1, o->oid.hash);
 737                 return 0;
 738         }
 739
 740         /*
 741          * At this point, the syntax look correct, so
 742          * if we do not get the needed object, we should
 743          * barf.
 744          */
 745         o = peel_to_type(name, len, o, expected_type);
 746         if (!o)
 747                 return -1;
 748
 749         hashcpy(sha1, o->oid.hash);
 750         if (sp[0] == '/') {
 751                 /* "$commit^{/foo}" */
 752                 char *prefix;
 753                 int ret;
 754                 struct commit_list *list = NULL;
 755
 756                 /*
 757                  * $commit^{/}. Some regex implementation may reject.
 758                  * We don't need regex anyway. '' pattern always matches.
 759                  */
 760                 if (sp[1] == '}')
 761                         return 0;
 762
 763                 prefix = xstrndup(sp + 1, name + len - 1 - (sp + 1));
 764                 commit_list_insert((struct commit *)o, &list);
 765                 ret = get_sha1_oneline(prefix, sha1, list);
 766                 free(prefix);
 767                 return ret;
 768         }
 769         return 0;
 770 }
 771
 772 static int get_describe_name(const char *name, int len, unsigned char *sha1)
 773 {
 774         const char *cp;
 775         unsigned flags = GET_SHA1_QUIETLY | GET_SHA1_COMMIT;
 776
 777         for (cp = name + len - 1; name + 2 <= cp; cp--) {
 778                 char ch = *cp;
 779                 if (!isxdigit(ch)) {
 780                         /* We must be looking at g in "SOMETHING-g"
 781                          * for it to be describe output.
 782                          */
 783                         if (ch == 'g' && cp[-1] == '-') {
 784                                 cp++;
 785                                 len -= cp - name;
 786                                 return get_short_sha1(cp, len, sha1, flags);
 787                         }
 788                 }
 789         }
 790         return -1;
 791 }
 792
 793 static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags)
 794 {
 795         int ret, has_suffix;
 796         const char *cp;
 797
 798         /*
 799          * "name~3" is "name^^^", "name~" is "name~1", and "name^" is "name^1".
 800          */
 801         has_suffix = 0;
 802         for (cp = name + len - 1; name <= cp; cp--) {
 803                 int ch = *cp;
 804                 if ('0' <= ch && ch <= '9')
 805                         continue;
 806                 if (ch == '~' || ch == '^')
 807                         has_suffix = ch;
 808                 break;
 809         }
 810
 811         if (has_suffix) {
 812                 int num = 0;
 813                 int len1 = cp - name;
 814                 cp++;
 815                 while (cp < name + len)
 816                         num = num * 10 + *cp++ - '0';
 817                 if (!num && len1 == len - 1)
 818                         num = 1;
 819                 if (has_suffix == '^')
 820                         return get_parent(name, len1, sha1, num);
 821                 /* else if (has_suffix == '~') -- goes without saying */
 822                 return get_nth_ancestor(name, len1, sha1, num);
 823         }
 824
 825         ret = peel_onion(name, len, sha1, lookup_flags);
 826         if (!ret)
 827                 return 0;
 828
 829         ret = get_sha1_basic(name, len, sha1, lookup_flags);
 830         if (!ret)
 831                 return 0;
 832
 833         /* It could be describe output that is "SOMETHING-gXXXX" */
 834         ret = get_describe_name(name, len, sha1);
 835         if (!ret)
 836                 return 0;
 837
 838         return get_short_sha1(name, len, sha1, lookup_flags);
 839 }
 840
 841 /*
 842  * This interprets names like ':/Initial revision of "git"' by searching
 843  * through history and returning the first commit whose message starts
 844  * the given regular expression.
 845  *
 846  * For negative-matching, prefix the pattern-part with '!-', like: ':/!-WIP'.
 847  *
 848  * For a literal '!' character at the beginning of a pattern, you have to repeat
 849  * that, like: ':/!!foo'
 850  *
 851  * For future extension, all other sequences beginning with ':/!' are reserved.
 852  */
 853
 854 /* Remember to update object flag allocation in object.h */
 855 #define ONELINE_SEEN (1u<<20)
 856
 857 static int handle_one_ref(const char *path, const struct object_id *oid,
 858                           int flag, void *cb_data)
 859 {
 860         struct commit_list **list = cb_data;
 861         struct object *object = parse_object(oid->hash);
 862         if (!object)
 863                 return 0;
 864         if (object->type == OBJ_TAG) {
 865                 object = deref_tag(object, path, strlen(path));
 866                 if (!object)
 867                         return 0;
 868         }
 869         if (object->type != OBJ_COMMIT)
 870                 return 0;
 871         commit_list_insert((struct commit *)object, list);
 872         return 0;
 873 }
 874
 875 static int get_sha1_oneline(const char *prefix, unsigned char *sha1,
 876                             struct commit_list *list)
 877 {
 878         struct commit_list *backup = NULL, *l;
 879         int found = 0;
 880         int negative = 0;
 881         regex_t regex;
 882
 883         if (prefix[0] == '!') {
 884                 prefix++;
 885
 886                 if (prefix[0] == '-') {
 887                         prefix++;
 888                         negative = 1;
 889                 } else if (prefix[0] != '!') {
 890                         return -1;
 891                 }
 892         }
 893
 894         if (regcomp(&regex, prefix, REG_EXTENDED))
 895                 return -1;
 896
 897         for (l = list; l; l = l->next) {
 898                 l->item->object.flags |= ONELINE_SEEN;
 899                 commit_list_insert(l->item, &backup);
 900         }
 901         while (list) {
 902                 const char *p, *buf;
 903                 struct commit *commit;
 904                 int matches;
 905
 906                 commit = pop_most_recent_commit(&list, ONELINE_SEEN);
 907                 if (!parse_object(commit->object.oid.hash))
 908                         continue;
 909                 buf = get_commit_buffer(commit, NULL);
 910                 p = strstr(buf, "\n\n");
 911                 matches = negative ^ (p && !regexec(&regex, p + 2, 0, NULL, 0));
 912                 unuse_commit_buffer(commit, buf);
 913
 914                 if (matches) {
 915                         hashcpy(sha1, commit->object.oid.hash);
 916                         found = 1;
 917                         break;
 918                 }
 919         }
 920         regfree(&regex);
 921         free_commit_list(list);
 922         for (l = backup; l; l = l->next)
 923                 clear_commit_marks(l->item, ONELINE_SEEN);
 924         free_commit_list(backup);
 925         return found ? 0 : -1;
 926 }
 927
 928 struct grab_nth_branch_switch_cbdata {
 929         int remaining;
 930         struct strbuf buf;
 931 };
 932
 933 static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
 934                                   const char *email, unsigned long timestamp, int tz,
 935                                   const char *message, void *cb_data)
 936 {
 937         struct grab_nth_branch_switch_cbdata *cb = cb_data;
 938         const char *match = NULL, *target = NULL;
 939         size_t len;
 940
 941         if (skip_prefix(message, "checkout: moving from ", &match))
 942                 target = strstr(match, " to ");
 943
 944         if (!match || !target)
 945                 return 0;
 946         if (--(cb->remaining) == 0) {
 947                 len = target - match;
 948                 strbuf_reset(&cb->buf);
 949                 strbuf_add(&cb->buf, match, len);
 950                 return 1; /* we are done */
 951         }
 952         return 0;
 953 }
 954
 955 /*
 956  * Parse @{-N} syntax, return the number of characters parsed
 957  * if successful; otherwise signal an error with negative value.
 958  */
 959 static int interpret_nth_prior_checkout(const char *name, int namelen,
 960                                         struct strbuf *buf)
 961 {
 962         long nth;
 963         int retval;
 964         struct grab_nth_branch_switch_cbdata cb;
 965         const char *brace;
 966         char *num_end;
 967
 968         if (namelen < 4)
 969                 return -1;
 970         if (name[0] != '@' || name[1] != '{' || name[2] != '-')
 971                 return -1;
 972         brace = memchr(name, '}', namelen);
 973         if (!brace)
 974                 return -1;
 975         nth = strtol(name + 3, &num_end, 10);
 976         if (num_end != brace)
 977                 return -1;
 978         if (nth <= 0)
 979                 return -1;
 980         cb.remaining = nth;
 981         strbuf_init(&cb.buf, 20);
 982
 983         retval = 0;
 984         if (0 < for_each_reflog_ent_reverse("HEAD", grab_nth_branch_switch, &cb)) {
 985                 strbuf_reset(buf);
 986                 strbuf_addbuf(buf, &cb.buf);
 987                 retval = brace - name + 1;
 988         }
 989
 990         strbuf_release(&cb.buf);
 991         return retval;
 992 }
 993
 994 int get_oid_mb(const char *name, struct object_id *oid)
 995 {
 996         struct commit *one, *two;
 997         struct commit_list *mbs;
 998         struct object_id oid_tmp;
 999         const char *dots;
1000         int st;
1001
1002         dots = strstr(name, "...");
1003         if (!dots)
1004                 return get_oid(name, oid);
1005         if (dots == name)
1006                 st = get_oid("HEAD", &oid_tmp);
1007         else {
1008                 struct strbuf sb;
1009                 strbuf_init(&sb, dots - name);
1010                 strbuf_add(&sb, name, dots - name);
1011                 st = get_sha1_committish(sb.buf, oid_tmp.hash);
1012                 strbuf_release(&sb);
1013         }
1014         if (st)
1015                 return st;
1016         one = lookup_commit_reference_gently(oid_tmp.hash, 0);
1017         if (!one)
1018                 return -1;
1019
1020         if (get_sha1_committish(dots[3] ? (dots + 3) : "HEAD", oid_tmp.hash))
1021                 return -1;
1022         two = lookup_commit_reference_gently(oid_tmp.hash, 0);
1023         if (!two)
1024                 return -1;
1025         mbs = get_merge_bases(one, two);
1026         if (!mbs || mbs->next)
1027                 st = -1;
1028         else {
1029                 st = 0;
1030                 oidcpy(oid, &mbs->item->object.oid);
1031         }
1032         free_commit_list(mbs);
1033         return st;
1034 }
1035
1036 /* parse @something syntax, when 'something' is not {.*} */
1037 static int interpret_empty_at(const char *name, int namelen, int len, struct strbuf *buf)
1038 {
1039         const char *next;
1040
1041         if (len || name[1] == '{')
1042                 return -1;
1043
1044         /* make sure it's a single @, or @@{.*}, not @foo */
1045         next = memchr(name + len + 1, '@', namelen - len - 1);
1046         if (next && next[1] != '{')
1047                 return -1;
1048         if (!next)
1049                 next = name + namelen;
1050         if (next != name + 1)
1051                 return -1;
1052
1053         strbuf_reset(buf);
1054         strbuf_add(buf, "HEAD", 4);
1055         return 1;
1056 }
1057
1058 static int reinterpret(const char *name, int namelen, int len, struct strbuf *buf)
1059 {
1060         /* we have extra data, which might need further processing */
1061         struct strbuf tmp = STRBUF_INIT;
1062         int used = buf->len;
1063         int ret;
1064
1065         strbuf_add(buf, name + len, namelen - len);
1066         ret = interpret_branch_name(buf->buf, buf->len, &tmp);
1067         /* that data was not interpreted, remove our cruft */
1068         if (ret < 0) {
1069                 strbuf_setlen(buf, used);
1070                 return len;
1071         }
1072         strbuf_reset(buf);
1073         strbuf_addbuf(buf, &tmp);
1074         strbuf_release(&tmp);
1075         /* tweak for size of {-N} versus expanded ref name */
1076         return ret - used + len;
1077 }
1078
1079 static void set_shortened_ref(struct strbuf *buf, const char *ref)
1080 {
1081         char *s = shorten_unambiguous_ref(ref, 0);
1082         strbuf_reset(buf);
1083         strbuf_addstr(buf, s);
1084         free(s);
1085 }
1086
1087 static int interpret_branch_mark(const char *name, int namelen,
1088                                  int at, struct strbuf *buf,
1089                                  int (*get_mark)(const char *, int),
1090                                  const char *(*get_data)(struct branch *,
1091                                                          struct strbuf *))
1092 {
1093         int len;
1094         struct branch *branch;
1095         struct strbuf err = STRBUF_INIT;
1096         const char *value;
1097
1098         len = get_mark(name + at, namelen - at);
1099         if (!len)
1100                 return -1;
1101
1102         if (memchr(name, ':', at))
1103                 return -1;
1104
1105         if (at) {
1106                 char *name_str = xmemdupz(name, at);
1107                 branch = branch_get(name_str);
1108                 free(name_str);
1109         } else
1110                 branch = branch_get(NULL);
1111
1112         value = get_data(branch, &err);
1113         if (!value)
1114                 die("%s", err.buf);
1115
1116         set_shortened_ref(buf, value);
1117         return len + at;
1118 }
1119
1120 /*
1121  * This reads short-hand syntax that not only evaluates to a commit
1122  * object name, but also can act as if the end user spelled the name
1123  * of the branch from the command line.
1124  *
1125  * - "@{-N}" finds the name of the Nth previous branch we were on, and
1126  *   places the name of the branch in the given buf and returns the
1127  *   number of characters parsed if successful.
1128  *
1129  * - "<branch>@{upstream}" finds the name of the other ref that
1130  *   <branch> is configured to merge with (missing <branch> defaults
1131  *   to the current branch), and places the name of the branch in the
1132  *   given buf and returns the number of characters parsed if
1133  *   successful.
1134  *
1135  * If the input is not of the accepted format, it returns a negative
1136  * number to signal an error.
1137  *
1138  * If the input was ok but there are not N branch switches in the
1139  * reflog, it returns 0.
1140  */
1141 int interpret_branch_name(const char *name, int namelen, struct strbuf *buf)
1142 {
1143         char *at;
1144         const char *start;
1145         int len = interpret_nth_prior_checkout(name, namelen, buf);
1146
1147         if (!namelen)
1148                 namelen = strlen(name);
1149
1150         if (!len) {
1151                 return len; /* syntax Ok, not enough switches */
1152         } else if (len > 0) {
1153                 if (len == namelen)
1154                         return len; /* consumed all */
1155                 else
1156                         return reinterpret(name, namelen, len, buf);
1157         }
1158
1159         for (start = name;
1160              (at = memchr(start, '@', namelen - (start - name)));
1161              start = at + 1) {
1162
1163                 len = interpret_empty_at(name, namelen, at - name, buf);
1164                 if (len > 0)
1165                         return reinterpret(name, namelen, len, buf);
1166
1167                 len = interpret_branch_mark(name, namelen, at - name, buf,
1168                                             upstream_mark, branch_get_upstream);
1169                 if (len > 0)
1170                         return len;
1171
1172                 len = interpret_branch_mark(name, namelen, at - name, buf,
1173                                             push_mark, branch_get_push);
1174                 if (len > 0)
1175                         return len;
1176         }
1177
1178         return -1;
1179 }
1180
1181 int strbuf_branchname(struct strbuf *sb, const char *name)
1182 {
1183         int len = strlen(name);
1184         int used = interpret_branch_name(name, len, sb);
1185
1186         if (used == len)
1187                 return 0;
1188         if (used < 0)
1189                 used = 0;
1190         strbuf_add(sb, name + used, len - used);
1191         return len;
1192 }
1193
1194 int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
1195 {
1196         strbuf_branchname(sb, name);
1197         if (name[0] == '-')
1198                 return -1;
1199         strbuf_splice(sb, 0, 0, "refs/heads/", 11);
1200         return check_refname_format(sb->buf, 0);
1201 }
1202
1203 /*
1204  * This is like "get_sha1_basic()", except it allows "sha1 expressions",
1205  * notably "xyz^" for "parent of xyz"
1206  */
1207 int get_sha1(const char *name, unsigned char *sha1)
1208 {
1209         struct object_context unused;
1210         return get_sha1_with_context(name, 0, sha1, &unused);
1211 }
1212
1213 /*
1214  * This is like "get_sha1()", but for struct object_id.
1215  */
1216 int get_oid(const char *name, struct object_id *oid)
1217 {
1218         return get_sha1(name, oid->hash);
1219 }
1220
1221
1222 /*
1223  * Many callers know that the user meant to name a commit-ish by
1224  * syntactical positions where the object name appears.  Calling this
1225  * function allows the machinery to disambiguate shorter-than-unique
1226  * abbreviated object names between commit-ish and others.
1227  *
1228  * Note that this does NOT error out when the named object is not a
1229  * commit-ish. It is merely to give a hint to the disambiguation
1230  * machinery.
1231  */
1232 int get_sha1_committish(const char *name, unsigned char *sha1)
1233 {
1234         struct object_context unused;
1235         return get_sha1_with_context(name, GET_SHA1_COMMITTISH,
1236                                      sha1, &unused);
1237 }
1238
1239 int get_sha1_treeish(const char *name, unsigned char *sha1)
1240 {
1241         struct object_context unused;
1242         return get_sha1_with_context(name, GET_SHA1_TREEISH,
1243                                      sha1, &unused);
1244 }
1245
1246 int get_sha1_commit(const char *name, unsigned char *sha1)
1247 {
1248         struct object_context unused;
1249         return get_sha1_with_context(name, GET_SHA1_COMMIT,
1250                                      sha1, &unused);
1251 }
1252
1253 int get_sha1_tree(const char *name, unsigned char *sha1)
1254 {
1255         struct object_context unused;
1256         return get_sha1_with_context(name, GET_SHA1_TREE,
1257                                      sha1, &unused);
1258 }
1259
1260 int get_sha1_blob(const char *name, unsigned char *sha1)
1261 {
1262         struct object_context unused;
1263         return get_sha1_with_context(name, GET_SHA1_BLOB,
1264                                      sha1, &unused);
1265 }
1266
1267 /* Must be called only when object_name:filename doesn't exist. */
1268 static void diagnose_invalid_sha1_path(const char *prefix,
1269                                        const char *filename,
1270                                        const unsigned char *tree_sha1,
1271                                        const char *object_name,
1272                                        int object_name_len)
1273 {
1274         unsigned char sha1[20];
1275         unsigned mode;
1276
1277         if (!prefix)
1278                 prefix = "";
1279
1280         if (file_exists(filename))
1281                 die("Path '%s' exists on disk, but not in '%.*s'.",
1282                     filename, object_name_len, object_name);
1283         if (errno == ENOENT || errno == ENOTDIR) {
1284                 char *fullname = xstrfmt("%s%s", prefix, filename);
1285
1286                 if (!get_tree_entry(tree_sha1, fullname,
1287                                     sha1, &mode)) {
1288                         die("Path '%s' exists, but not '%s'.\n"
1289                             "Did you mean '%.*s:%s' aka '%.*s:./%s'?",
1290                             fullname,
1291                             filename,
1292                             object_name_len, object_name,
1293                             fullname,
1294                             object_name_len, object_name,
1295                             filename);
1296                 }
1297                 die("Path '%s' does not exist in '%.*s'",
1298                     filename, object_name_len, object_name);
1299         }
1300 }
1301
1302 /* Must be called only when :stage:filename doesn't exist. */
1303 static void diagnose_invalid_index_path(int stage,
1304                                         const char *prefix,
1305                                         const char *filename)
1306 {
1307         const struct cache_entry *ce;
1308         int pos;
1309         unsigned namelen = strlen(filename);
1310         struct strbuf fullname = STRBUF_INIT;
1311
1312         if (!prefix)
1313                 prefix = "";
1314
1315         /* Wrong stage number? */
1316         pos = cache_name_pos(filename, namelen);
1317         if (pos < 0)
1318                 pos = -pos - 1;
1319         if (pos < active_nr) {
1320                 ce = active_cache[pos];
1321                 if (ce_namelen(ce) == namelen &&
1322                     !memcmp(ce->name, filename, namelen))
1323                         die("Path '%s' is in the index, but not at stage %d.\n"
1324                             "Did you mean ':%d:%s'?",
1325                             filename, stage,
1326                             ce_stage(ce), filename);
1327         }
1328
1329         /* Confusion between relative and absolute filenames? */
1330         strbuf_addstr(&fullname, prefix);
1331         strbuf_addstr(&fullname, filename);
1332         pos = cache_name_pos(fullname.buf, fullname.len);
1333         if (pos < 0)
1334                 pos = -pos - 1;
1335         if (pos < active_nr) {
1336                 ce = active_cache[pos];
1337                 if (ce_namelen(ce) == fullname.len &&
1338                     !memcmp(ce->name, fullname.buf, fullname.len))
1339                         die("Path '%s' is in the index, but not '%s'.\n"
1340                             "Did you mean ':%d:%s' aka ':%d:./%s'?",
1341                             fullname.buf, filename,
1342                             ce_stage(ce), fullname.buf,
1343                             ce_stage(ce), filename);
1344         }
1345
1346         if (file_exists(filename))
1347                 die("Path '%s' exists on disk, but not in the index.", filename);
1348         if (errno == ENOENT || errno == ENOTDIR)
1349                 die("Path '%s' does not exist (neither on disk nor in the index).",
1350                     filename);
1351
1352         strbuf_release(&fullname);
1353 }
1354
1355
1356 static char *resolve_relative_path(const char *rel)
1357 {
1358         if (!starts_with(rel, "./") && !starts_with(rel, "../"))
1359                 return NULL;
1360
1361         if (!is_inside_work_tree())
1362                 die("relative path syntax can't be used outside working tree.");
1363
1364         /* die() inside prefix_path() if resolved path is outside worktree */
1365         return prefix_path(startup_info->prefix,
1366                            startup_info->prefix ? strlen(startup_info->prefix) : 0,
1367                            rel);
1368 }
1369
1370 static int get_sha1_with_context_1(const char *name,
1371                                    unsigned flags,
1372                                    const char *prefix,
1373                                    unsigned char *sha1,
1374                                    struct object_context *oc)
1375 {
1376         int ret, bracket_depth;
1377         int namelen = strlen(name);
1378         const char *cp;
1379         int only_to_die = flags & GET_SHA1_ONLY_TO_DIE;
1380
1381         if (only_to_die)
1382                 flags |= GET_SHA1_QUIETLY;
1383
1384         memset(oc, 0, sizeof(*oc));
1385         oc->mode = S_IFINVALID;
1386         ret = get_sha1_1(name, namelen, sha1, flags);
1387         if (!ret)
1388                 return ret;
1389         /*
1390          * sha1:path --> object name of path in ent sha1
1391          * :path -> object name of absolute path in index
1392          * :./path -> object name of path relative to cwd in index
1393          * :[0-3]:path -> object name of path in index at stage
1394          * :/foo -> recent commit matching foo
1395          */
1396         if (name[0] == ':') {
1397                 int stage = 0;
1398                 const struct cache_entry *ce;
1399                 char *new_path = NULL;
1400                 int pos;
1401                 if (!only_to_die && namelen > 2 && name[1] == '/') {
1402                         struct commit_list *list = NULL;
1403
1404                         for_each_ref(handle_one_ref, &list);
1405                         commit_list_sort_by_date(&list);
1406                         return get_sha1_oneline(name + 2, sha1, list);
1407                 }
1408                 if (namelen < 3 ||
1409                     name[2] != ':' ||
1410                     name[1] < '0' || '3' < name[1])
1411                         cp = name + 1;
1412                 else {
1413                         stage = name[1] - '0';
1414                         cp = name + 3;
1415                 }
1416                 new_path = resolve_relative_path(cp);
1417                 if (!new_path) {
1418                         namelen = namelen - (cp - name);
1419                 } else {
1420                         cp = new_path;
1421                         namelen = strlen(cp);
1422                 }
1423
1424                 strlcpy(oc->path, cp, sizeof(oc->path));
1425
1426                 if (!active_cache)
1427                         read_cache();
1428                 pos = cache_name_pos(cp, namelen);
1429                 if (pos < 0)
1430                         pos = -pos - 1;
1431                 while (pos < active_nr) {
1432                         ce = active_cache[pos];
1433                         if (ce_namelen(ce) != namelen ||
1434                             memcmp(ce->name, cp, namelen))
1435                                 break;
1436                         if (ce_stage(ce) == stage) {
1437                                 hashcpy(sha1, ce->oid.hash);
1438                                 oc->mode = ce->ce_mode;
1439                                 free(new_path);
1440                                 return 0;
1441                         }
1442                         pos++;
1443                 }
1444                 if (only_to_die && name[1] && name[1] != '/')
1445                         diagnose_invalid_index_path(stage, prefix, cp);
1446                 free(new_path);
1447                 return -1;
1448         }
1449         for (cp = name, bracket_depth = 0; *cp; cp++) {
1450                 if (*cp == '{')
1451                         bracket_depth++;
1452                 else if (bracket_depth && *cp == '}')
1453                         bracket_depth--;
1454                 else if (!bracket_depth && *cp == ':')
1455                         break;
1456         }
1457         if (*cp == ':') {
1458                 unsigned char tree_sha1[20];
1459                 int len = cp - name;
1460                 unsigned sub_flags = flags;
1461
1462                 sub_flags &= ~GET_SHA1_DISAMBIGUATORS;
1463                 sub_flags |= GET_SHA1_TREEISH;
1464
1465                 if (!get_sha1_1(name, len, tree_sha1, sub_flags)) {
1466                         const char *filename = cp+1;
1467                         char *new_filename = NULL;
1468
1469                         new_filename = resolve_relative_path(filename);
1470                         if (new_filename)
1471                                 filename = new_filename;
1472                         if (flags & GET_SHA1_FOLLOW_SYMLINKS) {
1473                                 ret = get_tree_entry_follow_symlinks(tree_sha1,
1474                                         filename, sha1, &oc->symlink_path,
1475                                         &oc->mode);
1476                         } else {
1477                                 ret = get_tree_entry(tree_sha1, filename,
1478                                                      sha1, &oc->mode);
1479                                 if (ret && only_to_die) {
1480                                         diagnose_invalid_sha1_path(prefix,
1481                                                                    filename,
1482                                                                    tree_sha1,
1483                                                                    name, len);
1484                                 }
1485                         }
1486                         hashcpy(oc->tree, tree_sha1);
1487                         strlcpy(oc->path, filename, sizeof(oc->path));
1488
1489                         free(new_filename);
1490                         return ret;
1491                 } else {
1492                         if (only_to_die)
1493                                 die("Invalid object name '%.*s'.", len, name);
1494                 }
1495         }
1496         return ret;
1497 }
1498
1499 /*
1500  * Call this function when you know "name" given by the end user must
1501  * name an object but it doesn't; the function _may_ die with a better
1502  * diagnostic message than "no such object 'name'", e.g. "Path 'doc' does not
1503  * exist in 'HEAD'" when given "HEAD:doc", or it may return in which case
1504  * you have a chance to diagnose the error further.
1505  */
1506 void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
1507 {
1508         struct object_context oc;
1509         unsigned char sha1[20];
1510         get_sha1_with_context_1(name, GET_SHA1_ONLY_TO_DIE, prefix, sha1, &oc);
1511 }
1512
1513 int get_sha1_with_context(const char *str, unsigned flags, unsigned char *sha1, struct object_context *orc)
1514 {
1515         if (flags & GET_SHA1_FOLLOW_SYMLINKS && flags & GET_SHA1_ONLY_TO_DIE)
1516                 die("BUG: incompatible flags for get_sha1_with_context");
1517         return get_sha1_with_context_1(str, flags, NULL, sha1, orc);
1518 }