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
  10 static int get_sha1_oneline(const char *, unsigned char *, struct commit_list *);
  11
  12 typedef int (*disambiguate_hint_fn)(const unsigned char *, void *);
  13
  14 struct disambiguate_state {
  15         disambiguate_hint_fn fn;
  16         void *cb_data;
  17         unsigned char candidate[20];
  18         unsigned candidate_exists:1;
  19         unsigned candidate_checked:1;
  20         unsigned candidate_ok:1;
  21         unsigned disambiguate_fn_used:1;
  22         unsigned ambiguous:1;
  23         unsigned always_call_fn:1;
  24 };
  25
  26 static void update_candidates(struct disambiguate_state *ds, const unsigned char *current)
  27 {
  28         if (ds->always_call_fn) {
  29                 ds->ambiguous = ds->fn(current, ds->cb_data) ? 1 : 0;
  30                 return;
  31         }
  32         if (!ds->candidate_exists) {
  33                 /* this is the first candidate */
  34                 hashcpy(ds->candidate, current);
  35                 ds->candidate_exists = 1;
  36                 return;
  37         } else if (!hashcmp(ds->candidate, current)) {
  38                 /* the same as what we already have seen */
  39                 return;
  40         }
  41
  42         if (!ds->fn) {
  43                 /* cannot disambiguate between ds->candidate and current */
  44                 ds->ambiguous = 1;
  45                 return;
  46         }
  47
  48         if (!ds->candidate_checked) {
  49                 ds->candidate_ok = ds->fn(ds->candidate, ds->cb_data);
  50                 ds->disambiguate_fn_used = 1;
  51                 ds->candidate_checked = 1;
  52         }
  53
  54         if (!ds->candidate_ok) {
  55                 /* discard the candidate; we know it does not satisfy fn */
  56                 hashcpy(ds->candidate, current);
  57                 ds->candidate_checked = 0;
  58                 return;
  59         }
  60
  61         /* if we reach this point, we know ds->candidate satisfies fn */
  62         if (ds->fn(current, ds->cb_data)) {
  63                 /*
  64                  * if both current and candidate satisfy fn, we cannot
  65                  * disambiguate.
  66                  */
  67                 ds->candidate_ok = 0;
  68                 ds->ambiguous = 1;
  69         }
  70
  71         /* otherwise, current can be discarded and candidate is still good */
  72 }
  73
  74 static void find_short_object_filename(int len, const char *hex_pfx, struct disambiguate_state *ds)
  75 {
  76         struct alternate_object_database *alt;
  77         char hex[40];
  78         static struct alternate_object_database *fakeent;
  79
  80         if (!fakeent) {
  81                 /*
  82                  * Create a "fake" alternate object database that
  83                  * points to our own object database, to make it
  84                  * easier to get a temporary working space in
  85                  * alt->name/alt->base while iterating over the
  86                  * object databases including our own.
  87                  */
  88                 const char *objdir = get_object_directory();
  89                 int objdir_len = strlen(objdir);
  90                 int entlen = objdir_len + 43;
  91                 fakeent = xmalloc(sizeof(*fakeent) + entlen);
  92                 memcpy(fakeent->base, objdir, objdir_len);
  93                 fakeent->name = fakeent->base + objdir_len + 1;
  94                 fakeent->name[-1] = '/';
  95         }
  96         fakeent->next = alt_odb_list;
  97
  98         sprintf(hex, "%.2s", hex_pfx);
  99         for (alt = fakeent; alt && !ds->ambiguous; alt = alt->next) {
 100                 struct dirent *de;
 101                 DIR *dir;
 102                 sprintf(alt->name, "%.2s/", hex_pfx);
 103                 dir = opendir(alt->base);
 104                 if (!dir)
 105                         continue;
 106
 107                 while (!ds->ambiguous && (de = readdir(dir)) != NULL) {
 108                         unsigned char sha1[20];
 109
 110                         if (strlen(de->d_name) != 38)
 111                                 continue;
 112                         if (memcmp(de->d_name, hex_pfx + 2, len - 2))
 113                                 continue;
 114                         memcpy(hex + 2, de->d_name, 38);
 115                         if (!get_sha1_hex(hex, sha1))
 116                                 update_candidates(ds, sha1);
 117                 }
 118                 closedir(dir);
 119         }
 120 }
 121
 122 static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
 123 {
 124         do {
 125                 if (*a != *b)
 126                         return 0;
 127                 a++;
 128                 b++;
 129                 len -= 2;
 130         } while (len > 1);
 131         if (len)
 132                 if ((*a ^ *b) & 0xf0)
 133                         return 0;
 134         return 1;
 135 }
 136
 137 static void unique_in_pack(int len,
 138                           const unsigned char *bin_pfx,
 139                            struct packed_git *p,
 140                            struct disambiguate_state *ds)
 141 {
 142         uint32_t num, last, i, first = 0;
 143         const unsigned char *current = NULL;
 144
 145         open_pack_index(p);
 146         num = p->num_objects;
 147         last = num;
 148         while (first < last) {
 149                 uint32_t mid = (first + last) / 2;
 150                 const unsigned char *current;
 151                 int cmp;
 152
 153                 current = nth_packed_object_sha1(p, mid);
 154                 cmp = hashcmp(bin_pfx, current);
 155                 if (!cmp) {
 156                         first = mid;
 157                         break;
 158                 }
 159                 if (cmp > 0) {
 160                         first = mid+1;
 161                         continue;
 162                 }
 163                 last = mid;
 164         }
 165
 166         /*
 167          * At this point, "first" is the location of the lowest object
 168          * with an object name that could match "bin_pfx".  See if we have
 169          * 0, 1 or more objects that actually match(es).
 170          */
 171         for (i = first; i < num && !ds->ambiguous; i++) {
 172                 current = nth_packed_object_sha1(p, i);
 173                 if (!match_sha(len, bin_pfx, current))
 174                         break;
 175                 update_candidates(ds, current);
 176         }
 177 }
 178
 179 static void find_short_packed_object(int len, const unsigned char *bin_pfx,
 180                                      struct disambiguate_state *ds)
 181 {
 182         struct packed_git *p;
 183
 184         prepare_packed_git();
 185         for (p = packed_git; p && !ds->ambiguous; p = p->next)
 186                 unique_in_pack(len, bin_pfx, p, ds);
 187 }
 188
 189 #define SHORT_NAME_NOT_FOUND (-1)
 190 #define SHORT_NAME_AMBIGUOUS (-2)
 191
 192 static int finish_object_disambiguation(struct disambiguate_state *ds,
 193                                         unsigned char *sha1)
 194 {
 195         if (ds->ambiguous)
 196                 return SHORT_NAME_AMBIGUOUS;
 197
 198         if (!ds->candidate_exists)
 199                 return SHORT_NAME_NOT_FOUND;
 200
 201         if (!ds->candidate_checked)
 202                 /*
 203                  * If this is the only candidate, there is no point
 204                  * calling the disambiguation hint callback.
 205                  *
 206                  * On the other hand, if the current candidate
 207                  * replaced an earlier candidate that did _not_ pass
 208                  * the disambiguation hint callback, then we do have
 209                  * more than one objects that match the short name
 210                  * given, so we should make sure this one matches;
 211                  * otherwise, if we discovered this one and the one
 212                  * that we previously discarded in the reverse order,
 213                  * we would end up showing different results in the
 214                  * same repository!
 215                  */
 216                 ds->candidate_ok = (!ds->disambiguate_fn_used ||
 217                                     ds->fn(ds->candidate, ds->cb_data));
 218
 219         if (!ds->candidate_ok)
 220                 return SHORT_NAME_AMBIGUOUS;
 221
 222         hashcpy(sha1, ds->candidate);
 223         return 0;
 224 }
 225
 226 static int disambiguate_commit_only(const unsigned char *sha1, void *cb_data_unused)
 227 {
 228         int kind = sha1_object_info(sha1, NULL);
 229         return kind == OBJ_COMMIT;
 230 }
 231
 232 static int disambiguate_committish_only(const unsigned char *sha1, void *cb_data_unused)
 233 {
 234         struct object *obj;
 235         int kind;
 236
 237         kind = sha1_object_info(sha1, NULL);
 238         if (kind == OBJ_COMMIT)
 239                 return 1;
 240         if (kind != OBJ_TAG)
 241                 return 0;
 242
 243         /* We need to do this the hard way... */
 244         obj = deref_tag(parse_object(sha1), NULL, 0);
 245         if (obj && obj->type == OBJ_COMMIT)
 246                 return 1;
 247         return 0;
 248 }
 249
 250 static int disambiguate_tree_only(const unsigned char *sha1, void *cb_data_unused)
 251 {
 252         int kind = sha1_object_info(sha1, NULL);
 253         return kind == OBJ_TREE;
 254 }
 255
 256 static int disambiguate_treeish_only(const unsigned char *sha1, void *cb_data_unused)
 257 {
 258         struct object *obj;
 259         int kind;
 260
 261         kind = sha1_object_info(sha1, NULL);
 262         if (kind == OBJ_TREE || kind == OBJ_COMMIT)
 263                 return 1;
 264         if (kind != OBJ_TAG)
 265                 return 0;
 266
 267         /* We need to do this the hard way... */
 268         obj = deref_tag(lookup_object(sha1), NULL, 0);
 269         if (obj && (obj->type == OBJ_TREE || obj->type == OBJ_COMMIT))
 270                 return 1;
 271         return 0;
 272 }
 273
 274 static int disambiguate_blob_only(const unsigned char *sha1, void *cb_data_unused)
 275 {
 276         int kind = sha1_object_info(sha1, NULL);
 277         return kind == OBJ_BLOB;
 278 }
 279
 280 static int prepare_prefixes(const char *name, int len,
 281                             unsigned char *bin_pfx,
 282                             char *hex_pfx)
 283 {
 284         int i;
 285
 286         hashclr(bin_pfx);
 287         memset(hex_pfx, 'x', 40);
 288         for (i = 0; i < len ;i++) {
 289                 unsigned char c = name[i];
 290                 unsigned char val;
 291                 if (c >= '0' && c <= '9')
 292                         val = c - '0';
 293                 else if (c >= 'a' && c <= 'f')
 294                         val = c - 'a' + 10;
 295                 else if (c >= 'A' && c <='F') {
 296                         val = c - 'A' + 10;
 297                         c -= 'A' - 'a';
 298                 }
 299                 else
 300                         return -1;
 301                 hex_pfx[i] = c;
 302                 if (!(i & 1))
 303                         val <<= 4;
 304                 bin_pfx[i >> 1] |= val;
 305         }
 306         return 0;
 307 }
 308
 309 static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 310                           unsigned flags)
 311 {
 312         int status;
 313         char hex_pfx[40];
 314         unsigned char bin_pfx[20];
 315         struct disambiguate_state ds;
 316         int quietly = !!(flags & GET_SHA1_QUIETLY);
 317
 318         if (len < MINIMUM_ABBREV || len > 40)
 319                 return -1;
 320         if (prepare_prefixes(name, len, bin_pfx, hex_pfx) < 0)
 321                 return -1;
 322
 323         prepare_alt_odb();
 324
 325         memset(&ds, 0, sizeof(ds));
 326         if (flags & GET_SHA1_COMMIT)
 327                 ds.fn = disambiguate_commit_only;
 328         else if (flags & GET_SHA1_COMMITTISH)
 329                 ds.fn = disambiguate_committish_only;
 330         else if (flags & GET_SHA1_TREE)
 331                 ds.fn = disambiguate_tree_only;
 332         else if (flags & GET_SHA1_TREEISH)
 333                 ds.fn = disambiguate_treeish_only;
 334         else if (flags & GET_SHA1_BLOB)
 335                 ds.fn = disambiguate_blob_only;
 336
 337         find_short_object_filename(len, hex_pfx, &ds);
 338         find_short_packed_object(len, bin_pfx, &ds);
 339         status = finish_object_disambiguation(&ds, sha1);
 340
 341         if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
 342                 return error("short SHA1 %.*s is ambiguous.", len, hex_pfx);
 343         return status;
 344 }
 345
 346 int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
 347 {
 348         char hex_pfx[40];
 349         unsigned char bin_pfx[20];
 350         struct disambiguate_state ds;
 351         int len = strlen(prefix);
 352
 353         if (len < MINIMUM_ABBREV || len > 40)
 354                 return -1;
 355         if (prepare_prefixes(prefix, len, bin_pfx, hex_pfx) < 0)
 356                 return -1;
 357
 358         prepare_alt_odb();
 359
 360         memset(&ds, 0, sizeof(ds));
 361         ds.always_call_fn = 1;
 362         ds.cb_data = cb_data;
 363         ds.fn = fn;
 364
 365         find_short_object_filename(len, hex_pfx, &ds);
 366         find_short_packed_object(len, bin_pfx, &ds);
 367         return ds.ambiguous;
 368 }
 369
 370 const char *find_unique_abbrev(const unsigned char *sha1, int len)
 371 {
 372         int status, exists;
 373         static char hex[41];
 374
 375         exists = has_sha1_file(sha1);
 376         memcpy(hex, sha1_to_hex(sha1), 40);
 377         if (len == 40 || !len)
 378                 return hex;
 379         while (len < 40) {
 380                 unsigned char sha1_ret[20];
 381                 status = get_short_sha1(hex, len, sha1_ret, GET_SHA1_QUIETLY);
 382                 if (exists
 383                     ? !status
 384                     : status == SHORT_NAME_NOT_FOUND) {
 385                         hex[len] = 0;
 386                         return hex;
 387                 }
 388                 len++;
 389         }
 390         return hex;
 391 }
 392
 393 static int ambiguous_path(const char *path, int len)
 394 {
 395         int slash = 1;
 396         int cnt;
 397
 398         for (cnt = 0; cnt < len; cnt++) {
 399                 switch (*path++) {
 400                 case '\0':
 401                         break;
 402                 case '/':
 403                         if (slash)
 404                                 break;
 405                         slash = 1;
 406                         continue;
 407                 case '.':
 408                         continue;
 409                 default:
 410                         slash = 0;
 411                         continue;
 412                 }
 413                 break;
 414         }
 415         return slash;
 416 }
 417
 418 static inline int upstream_mark(const char *string, int len)
 419 {
 420         const char *suffix[] = { "@{upstream}", "@{u}" };
 421         int i;
 422
 423         for (i = 0; i < ARRAY_SIZE(suffix); i++) {
 424                 int suffix_len = strlen(suffix[i]);
 425                 if (suffix_len <= len
 426                     && !memcmp(string, suffix[i], suffix_len))
 427                         return suffix_len;
 428         }
 429         return 0;
 430 }
 431
 432 static inline int tail_mark(const char *string, int len)
 433 {
 434         const char *suffix[] = { "@{tail}", "@{t}" };
 435         int i;
 436
 437         for (i = 0; i < ARRAY_SIZE(suffix); i++) {
 438                 int suffix_len = strlen(suffix[i]);
 439                 if (suffix_len <= len
 440                     && !memcmp(string, suffix[i], suffix_len))
 441                         return suffix_len;
 442         }
 443         return 0;
 444 }
 445
 446 static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags);
 447 static int interpret_nth_prior_checkout(const char *name, int namelen, struct strbuf *buf);
 448
 449 static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 450 {
 451         static const char *warn_msg = "refname '%.*s' is ambiguous.";
 452         static const char *object_name_msg = N_(
 453         "Git normally never creates a ref that ends with 40 hex characters\n"
 454         "because it will be ignored when you just specify 40-hex. These refs\n"
 455         "may be created by mistake. For example,\n"
 456         "\n"
 457         "  git checkout -b $br $(git rev-parse ...)\n"
 458         "\n"
 459         "where \"$br\" is somehow empty and a 40-hex ref is created. Please\n"
 460         "examine these refs and maybe delete them. Turn this message off by\n"
 461         "running \"git config advice.objectNameWarning false\"");
 462         unsigned char tmp_sha1[20];
 463         char *real_ref = NULL;
 464         int refs_found = 0;
 465         int at, reflog_len, nth_prior = 0;
 466
 467         if (len == 40 && !get_sha1_hex(str, sha1)) {
 468                 if (warn_ambiguous_refs && warn_on_object_refname_ambiguity) {
 469                         refs_found = dwim_ref(str, len, tmp_sha1, &real_ref);
 470                         if (refs_found > 0) {
 471                                 warning(warn_msg, len, str);
 472                                 if (advice_object_name_warning)
 473                                         fprintf(stderr, "%s\n", _(object_name_msg));
 474                         }
 475                         free(real_ref);
 476                 }
 477                 return 0;
 478         }
 479
 480         /* basic@{time or number or -number} format to query ref-log */
 481         reflog_len = at = 0;
 482         if (len && str[len-1] == '}') {
 483                 for (at = len-4; at >= 0; at--) {
 484                         if (str[at] == '@' && str[at+1] == '{') {
 485                                 if (str[at+2] == '-') {
 486                                         if (at != 0)
 487                                                 /* @{-N} not at start */
 488                                                 return -1;
 489                                         nth_prior = 1;
 490                                         continue;
 491                                 }
 492                                 if (!upstream_mark(str + at, len - at) && !tail_mark(str + at, len - at)) {
 493                                         reflog_len = (len-1) - (at+2);
 494                                         len = at;
 495                                 }
 496                                 break;
 497                         }
 498                 }
 499         }
 500
 501         /* Accept only unambiguous ref paths. */
 502         if (len && ambiguous_path(str, len))
 503                 return -1;
 504
 505         if (nth_prior) {
 506                 struct strbuf buf = STRBUF_INIT;
 507                 int detached;
 508
 509                 if (interpret_nth_prior_checkout(str, len, &buf) > 0) {
 510                         detached = (buf.len == 40 && !get_sha1_hex(buf.buf, sha1));
 511                         strbuf_release(&buf);
 512                         if (detached)
 513                                 return 0;
 514                 }
 515         }
 516
 517         if (!len && reflog_len)
 518                 /* allow "@{...}" to mean the current branch reflog */
 519                 refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
 520         else if (reflog_len)
 521                 refs_found = dwim_log(str, len, sha1, &real_ref);
 522         else
 523                 refs_found = dwim_ref(str, len, sha1, &real_ref);
 524
 525         if (!refs_found)
 526                 return -1;
 527
 528         if (warn_ambiguous_refs &&
 529             (refs_found > 1 ||
 530              !get_short_sha1(str, len, tmp_sha1, GET_SHA1_QUIETLY)))
 531                 warning(warn_msg, len, str);
 532
 533         if (reflog_len) {
 534                 int nth, i;
 535                 unsigned long at_time;
 536                 unsigned long co_time;
 537                 int co_tz, co_cnt;
 538
 539                 /* Is it asking for N-th entry, or approxidate? */
 540                 for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 541                         char ch = str[at+2+i];
 542                         if ('0' <= ch && ch <= '9')
 543                                 nth = nth * 10 + ch - '0';
 544                         else
 545                                 nth = -1;
 546                 }
 547                 if (100000000 <= nth) {
 548                         at_time = nth;
 549                         nth = -1;
 550                 } else if (0 <= nth)
 551                         at_time = 0;
 552                 else {
 553                         int errors = 0;
 554                         char *tmp = xstrndup(str + at + 2, reflog_len);
 555                         at_time = approxidate_careful(tmp, &errors);
 556                         free(tmp);
 557                         if (errors)
 558                                 return -1;
 559                 }
 560                 if (read_ref_at(real_ref, at_time, nth, sha1, NULL,
 561                                 &co_time, &co_tz, &co_cnt)) {
 562                         if (!len) {
 563                                 if (starts_with(real_ref, "refs/heads/")) {
 564                                         str = real_ref + 11;
 565                                         len = strlen(real_ref + 11);
 566                                 } else {
 567                                         /* detached HEAD */
 568                                         str = "HEAD";
 569                                         len = 4;
 570                                 }
 571                         }
 572                         if (at_time)
 573                                 warning("Log for '%.*s' only goes "
 574                                         "back to %s.", len, str,
 575                                         show_date(co_time, co_tz, DATE_RFC2822));
 576                         else {
 577                                 die("Log for '%.*s' only has %d entries.",
 578                                     len, str, co_cnt);
 579                         }
 580                 }
 581         }
 582
 583         free(real_ref);
 584         return 0;
 585 }
 586
 587 static int get_parent(const char *name, int len,
 588                       unsigned char *result, int idx)
 589 {
 590         unsigned char sha1[20];
 591         int ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 592         struct commit *commit;
 593         struct commit_list *p;
 594
 595         if (ret)
 596                 return ret;
 597         commit = lookup_commit_reference(sha1);
 598         if (parse_commit(commit))
 599                 return -1;
 600         if (!idx) {
 601                 hashcpy(result, commit->object.sha1);
 602                 return 0;
 603         }
 604         p = commit->parents;
 605         while (p) {
 606                 if (!--idx) {
 607                         hashcpy(result, p->item->object.sha1);
 608                         return 0;
 609                 }
 610                 p = p->next;
 611         }
 612         return -1;
 613 }
 614
 615 static int get_nth_ancestor(const char *name, int len,
 616                             unsigned char *result, int generation)
 617 {
 618         unsigned char sha1[20];
 619         struct commit *commit;
 620         int ret;
 621
 622         ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 623         if (ret)
 624                 return ret;
 625         commit = lookup_commit_reference(sha1);
 626         if (!commit)
 627                 return -1;
 628
 629         while (generation--) {
 630                 if (parse_commit(commit) || !commit->parents)
 631                         return -1;
 632                 commit = commit->parents->item;
 633         }
 634         hashcpy(result, commit->object.sha1);
 635         return 0;
 636 }
 637
 638 struct object *peel_to_type(const char *name, int namelen,
 639                             struct object *o, enum object_type expected_type)
 640 {
 641         if (name && !namelen)
 642                 namelen = strlen(name);
 643         while (1) {
 644                 if (!o || (!o->parsed && !parse_object(o->sha1)))
 645                         return NULL;
 646                 if (expected_type == OBJ_ANY || o->type == expected_type)
 647                         return o;
 648                 if (o->type == OBJ_TAG)
 649                         o = ((struct tag*) o)->tagged;
 650                 else if (o->type == OBJ_COMMIT)
 651                         o = &(((struct commit *) o)->tree->object);
 652                 else {
 653                         if (name)
 654                                 error("%.*s: expected %s type, but the object "
 655                                       "dereferences to %s type",
 656                                       namelen, name, typename(expected_type),
 657                                       typename(o->type));
 658                         return NULL;
 659                 }
 660         }
 661 }
 662
 663 static int peel_onion(const char *name, int len, unsigned char *sha1)
 664 {
 665         unsigned char outer[20];
 666         const char *sp;
 667         unsigned int expected_type = 0;
 668         unsigned lookup_flags = 0;
 669         struct object *o;
 670
 671         /*
 672          * "ref^{type}" dereferences ref repeatedly until you cannot
 673          * dereference anymore, or you get an object of given type,
 674          * whichever comes first.  "ref^{}" means just dereference
 675          * tags until you get a non-tag.  "ref^0" is a shorthand for
 676          * "ref^{commit}".  "commit^{tree}" could be used to find the
 677          * top-level tree of the given commit.
 678          */
 679         if (len < 4 || name[len-1] != '}')
 680                 return -1;
 681
 682         for (sp = name + len - 1; name <= sp; sp--) {
 683                 int ch = *sp;
 684                 if (ch == '{' && name < sp && sp[-1] == '^')
 685                         break;
 686         }
 687         if (sp <= name)
 688                 return -1;
 689
 690         sp++; /* beginning of type name, or closing brace for empty */
 691         if (starts_with(sp, "commit}"))
 692                 expected_type = OBJ_COMMIT;
 693         else if (starts_with(sp, "tag}"))
 694                 expected_type = OBJ_TAG;
 695         else if (starts_with(sp, "tree}"))
 696                 expected_type = OBJ_TREE;
 697         else if (starts_with(sp, "blob}"))
 698                 expected_type = OBJ_BLOB;
 699         else if (starts_with(sp, "object}"))
 700                 expected_type = OBJ_ANY;
 701         else if (sp[0] == '}')
 702                 expected_type = OBJ_NONE;
 703         else if (sp[0] == '/')
 704                 expected_type = OBJ_COMMIT;
 705         else
 706                 return -1;
 707
 708         if (expected_type == OBJ_COMMIT)
 709                 lookup_flags = GET_SHA1_COMMITTISH;
 710         else if (expected_type == OBJ_TREE)
 711                 lookup_flags = GET_SHA1_TREEISH;
 712
 713         if (get_sha1_1(name, sp - name - 2, outer, lookup_flags))
 714                 return -1;
 715
 716         o = parse_object(outer);
 717         if (!o)
 718                 return -1;
 719         if (!expected_type) {
 720                 o = deref_tag(o, name, sp - name - 2);
 721                 if (!o || (!o->parsed && !parse_object(o->sha1)))
 722                         return -1;
 723                 hashcpy(sha1, o->sha1);
 724                 return 0;
 725         }
 726
 727         /*
 728          * At this point, the syntax look correct, so
 729          * if we do not get the needed object, we should
 730          * barf.
 731          */
 732         o = peel_to_type(name, len, o, expected_type);
 733         if (!o)
 734                 return -1;
 735
 736         hashcpy(sha1, o->sha1);
 737         if (sp[0] == '/') {
 738                 /* "$commit^{/foo}" */
 739                 char *prefix;
 740                 int ret;
 741                 struct commit_list *list = NULL;
 742
 743                 /*
 744                  * $commit^{/}. Some regex implementation may reject.
 745                  * We don't need regex anyway. '' pattern always matches.
 746                  */
 747                 if (sp[1] == '}')
 748                         return 0;
 749
 750                 prefix = xstrndup(sp + 1, name + len - 1 - (sp + 1));
 751                 commit_list_insert((struct commit *)o, &list);
 752                 ret = get_sha1_oneline(prefix, sha1, list);
 753                 free(prefix);
 754                 return ret;
 755         }
 756         return 0;
 757 }
 758
 759 static int get_describe_name(const char *name, int len, unsigned char *sha1)
 760 {
 761         const char *cp;
 762         unsigned flags = GET_SHA1_QUIETLY | GET_SHA1_COMMIT;
 763
 764         for (cp = name + len - 1; name + 2 <= cp; cp--) {
 765                 char ch = *cp;
 766                 if (hexval(ch) & ~0377) {
 767                         /* We must be looking at g in "SOMETHING-g"
 768                          * for it to be describe output.
 769                          */
 770                         if (ch == 'g' && cp[-1] == '-') {
 771                                 cp++;
 772                                 len -= cp - name;
 773                                 return get_short_sha1(cp, len, sha1, flags);
 774                         }
 775                 }
 776         }
 777         return -1;
 778 }
 779
 780 static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags)
 781 {
 782         int ret, has_suffix;
 783         const char *cp;
 784
 785         /*
 786          * "name~3" is "name^^^", "name~" is "name~1", and "name^" is "name^1".
 787          */
 788         has_suffix = 0;
 789         for (cp = name + len - 1; name <= cp; cp--) {
 790                 int ch = *cp;
 791                 if ('0' <= ch && ch <= '9')
 792                         continue;
 793                 if (ch == '~' || ch == '^')
 794                         has_suffix = ch;
 795                 break;
 796         }
 797
 798         if (has_suffix) {
 799                 int num = 0;
 800                 int len1 = cp - name;
 801                 cp++;
 802                 while (cp < name + len)
 803                         num = num * 10 + *cp++ - '0';
 804                 if (!num && len1 == len - 1)
 805                         num = 1;
 806                 if (has_suffix == '^')
 807                         return get_parent(name, len1, sha1, num);
 808                 /* else if (has_suffix == '~') -- goes without saying */
 809                 return get_nth_ancestor(name, len1, sha1, num);
 810         }
 811
 812         ret = peel_onion(name, len, sha1);
 813         if (!ret)
 814                 return 0;
 815
 816         ret = get_sha1_basic(name, len, sha1);
 817         if (!ret)
 818                 return 0;
 819
 820         /* It could be describe output that is "SOMETHING-gXXXX" */
 821         ret = get_describe_name(name, len, sha1);
 822         if (!ret)
 823                 return 0;
 824
 825         return get_short_sha1(name, len, sha1, lookup_flags);
 826 }
 827
 828 /*
 829  * This interprets names like ':/Initial revision of "git"' by searching
 830  * through history and returning the first commit whose message starts
 831  * the given regular expression.
 832  *
 833  * For future extension, ':/!' is reserved. If you want to match a message
 834  * beginning with a '!', you have to repeat the exclamation mark.
 835  */
 836 #define ONELINE_SEEN (1u<<20)
 837
 838 static int handle_one_ref(const char *path,
 839                 const unsigned char *sha1, int flag, void *cb_data)
 840 {
 841         struct commit_list **list = cb_data;
 842         struct object *object = parse_object(sha1);
 843         if (!object)
 844                 return 0;
 845         if (object->type == OBJ_TAG) {
 846                 object = deref_tag(object, path, strlen(path));
 847                 if (!object)
 848                         return 0;
 849         }
 850         if (object->type != OBJ_COMMIT)
 851                 return 0;
 852         commit_list_insert_by_date((struct commit *)object, list);
 853         return 0;
 854 }
 855
 856 static int get_sha1_oneline(const char *prefix, unsigned char *sha1,
 857                             struct commit_list *list)
 858 {
 859         struct commit_list *backup = NULL, *l;
 860         int found = 0;
 861         regex_t regex;
 862
 863         if (prefix[0] == '!') {
 864                 if (prefix[1] != '!')
 865                         die ("Invalid search pattern: %s", prefix);
 866                 prefix++;
 867         }
 868
 869         if (regcomp(&regex, prefix, REG_EXTENDED))
 870                 die("Invalid search pattern: %s", prefix);
 871
 872         for (l = list; l; l = l->next) {
 873                 l->item->object.flags |= ONELINE_SEEN;
 874                 commit_list_insert(l->item, &backup);
 875         }
 876         while (list) {
 877                 char *p, *to_free = NULL;
 878                 struct commit *commit;
 879                 enum object_type type;
 880                 unsigned long size;
 881                 int matches;
 882
 883                 commit = pop_most_recent_commit(&list, ONELINE_SEEN);
 884                 if (!parse_object(commit->object.sha1))
 885                         continue;
 886                 if (commit->buffer)
 887                         p = commit->buffer;
 888                 else {
 889                         p = read_sha1_file(commit->object.sha1, &type, &size);
 890                         if (!p)
 891                                 continue;
 892                         to_free = p;
 893                 }
 894
 895                 p = strstr(p, "\n\n");
 896                 matches = p && !regexec(&regex, p + 2, 0, NULL, 0);
 897                 free(to_free);
 898
 899                 if (matches) {
 900                         hashcpy(sha1, commit->object.sha1);
 901                         found = 1;
 902                         break;
 903                 }
 904         }
 905         regfree(&regex);
 906         free_commit_list(list);
 907         for (l = backup; l; l = l->next)
 908                 clear_commit_marks(l->item, ONELINE_SEEN);
 909         free_commit_list(backup);
 910         return found ? 0 : -1;
 911 }
 912
 913 struct grab_nth_branch_switch_cbdata {
 914         int remaining;
 915         struct strbuf buf;
 916 };
 917
 918 static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
 919                                   const char *email, unsigned long timestamp, int tz,
 920                                   const char *message, void *cb_data)
 921 {
 922         struct grab_nth_branch_switch_cbdata *cb = cb_data;
 923         const char *match = NULL, *target = NULL;
 924         size_t len;
 925
 926         if (starts_with(message, "checkout: moving from ")) {
 927                 match = message + strlen("checkout: moving from ");
 928                 target = strstr(match, " to ");
 929         }
 930
 931         if (!match || !target)
 932                 return 0;
 933         if (--(cb->remaining) == 0) {
 934                 len = target - match;
 935                 strbuf_reset(&cb->buf);
 936                 strbuf_add(&cb->buf, match, len);
 937                 return 1; /* we are done */
 938         }
 939         return 0;
 940 }
 941
 942 /*
 943  * Parse @{-N} syntax, return the number of characters parsed
 944  * if successful; otherwise signal an error with negative value.
 945  */
 946 static int interpret_nth_prior_checkout(const char *name, int namelen,
 947                                         struct strbuf *buf)
 948 {
 949         long nth;
 950         int retval;
 951         struct grab_nth_branch_switch_cbdata cb;
 952         const char *brace;
 953         char *num_end;
 954
 955         if (namelen < 4)
 956                 return -1;
 957         if (name[0] != '@' || name[1] != '{' || name[2] != '-')
 958                 return -1;
 959         brace = memchr(name, '}', namelen);
 960         if (!brace)
 961                 return -1;
 962         nth = strtol(name + 3, &num_end, 10);
 963         if (num_end != brace)
 964                 return -1;
 965         if (nth <= 0)
 966                 return -1;
 967         cb.remaining = nth;
 968         strbuf_init(&cb.buf, 20);
 969
 970         retval = 0;
 971         if (0 < for_each_reflog_ent_reverse("HEAD", grab_nth_branch_switch, &cb)) {
 972                 strbuf_reset(buf);
 973                 strbuf_add(buf, cb.buf.buf, cb.buf.len);
 974                 retval = brace - name + 1;
 975         }
 976
 977         strbuf_release(&cb.buf);
 978         return retval;
 979 }
 980
 981 int get_sha1_mb(const char *name, unsigned char *sha1)
 982 {
 983         struct commit *one, *two;
 984         struct commit_list *mbs;
 985         unsigned char sha1_tmp[20];
 986         const char *dots;
 987         int st;
 988
 989         dots = strstr(name, "...");
 990         if (!dots)
 991                 return get_sha1(name, sha1);
 992         if (dots == name)
 993                 st = get_sha1("HEAD", sha1_tmp);
 994         else {
 995                 struct strbuf sb;
 996                 strbuf_init(&sb, dots - name);
 997                 strbuf_add(&sb, name, dots - name);
 998                 st = get_sha1_committish(sb.buf, sha1_tmp);
 999                 strbuf_release(&sb);
1000         }
1001         if (st)
1002                 return st;
1003         one = lookup_commit_reference_gently(sha1_tmp, 0);
1004         if (!one)
1005                 return -1;
1006
1007         if (get_sha1_committish(dots[3] ? (dots + 3) : "HEAD", sha1_tmp))
1008                 return -1;
1009         two = lookup_commit_reference_gently(sha1_tmp, 0);
1010         if (!two)
1011                 return -1;
1012         mbs = get_merge_bases(one, two, 1);
1013         if (!mbs || mbs->next)
1014                 st = -1;
1015         else {
1016                 st = 0;
1017                 hashcpy(sha1, mbs->item->object.sha1);
1018         }
1019         free_commit_list(mbs);
1020         return st;
1021 }
1022
1023 /* parse @something syntax, when 'something' is not {.*} */
1024 static int interpret_empty_at(const char *name, int namelen, int len, struct strbuf *buf)
1025 {
1026         const char *next;
1027
1028         if (len || name[1] == '{')
1029                 return -1;
1030
1031         /* make sure it's a single @, or @@{.*}, not @foo */
1032         next = memchr(name + len + 1, '@', namelen - len - 1);
1033         if (next && next[1] != '{')
1034                 return -1;
1035         if (!next)
1036                 next = name + namelen;
1037         if (next != name + 1)
1038                 return -1;
1039
1040         strbuf_reset(buf);
1041         strbuf_add(buf, "HEAD", 4);
1042         return 1;
1043 }
1044
1045 static int reinterpret(const char *name, int namelen, int len, struct strbuf *buf)
1046 {
1047         /* we have extra data, which might need further processing */
1048         struct strbuf tmp = STRBUF_INIT;
1049         int used = buf->len;
1050         int ret;
1051
1052         strbuf_add(buf, name + len, namelen - len);
1053         ret = interpret_branch_name(buf->buf, buf->len, &tmp);
1054         /* that data was not interpreted, remove our cruft */
1055         if (ret < 0) {
1056                 strbuf_setlen(buf, used);
1057                 return len;
1058         }
1059         strbuf_reset(buf);
1060         strbuf_addbuf(buf, &tmp);
1061         strbuf_release(&tmp);
1062         /* tweak for size of {-N} versus expanded ref name */
1063         return ret - used + len;
1064 }
1065
1066 static void set_shortened_ref(struct strbuf *buf, const char *ref)
1067 {
1068         char *s = shorten_unambiguous_ref(ref, 0);
1069         strbuf_reset(buf);
1070         strbuf_addstr(buf, s);
1071         free(s);
1072 }
1073
1074 static const char *get_upstream_branch(const char *branch_buf, int len)
1075 {
1076         char *branch = xstrndup(branch_buf, len);
1077         struct branch *upstream = branch_get(*branch ? branch : NULL);
1078
1079         /*
1080          * Upstream can be NULL only if branch refers to HEAD and HEAD
1081          * points to something different than a branch.
1082          */
1083         if (!upstream)
1084                 die(_("HEAD does not point to a branch"));
1085         if (!upstream->merge || !upstream->merge[0]->dst) {
1086                 if (!ref_exists(upstream->refname))
1087                         die(_("No such branch: '%s'"), branch);
1088                 if (!upstream->merge) {
1089                         die(_("No upstream configured for branch '%s'"),
1090                                 upstream->name);
1091                 }
1092                 die(
1093                         _("Upstream branch '%s' not stored as a remote-tracking branch"),
1094                         upstream->merge[0]->src);
1095         }
1096         free(branch);
1097
1098         return upstream->merge[0]->dst;
1099 }
1100
1101 static int interpret_upstream_mark(const char *name, int namelen,
1102                                    int at, struct strbuf *buf)
1103 {
1104         int len;
1105
1106         len = tail_mark(name + at, namelen - at);
1107         if (len) {
1108                 strbuf_reset(buf);
1109                 strbuf_addf(buf, "refs/tails/%.*s", at, name);
1110                 return len + at;
1111         }
1112         len = upstream_mark(name + at, namelen - at);
1113         if (!len)
1114                 return -1;
1115
1116         if (memchr(name, ':', at))
1117                 return -1;
1118
1119         set_shortened_ref(buf, get_upstream_branch(name, at));
1120         return len + at;
1121 }
1122
1123 /*
1124  * This reads short-hand syntax that not only evaluates to a commit
1125  * object name, but also can act as if the end user spelled the name
1126  * of the branch from the command line.
1127  *
1128  * - "@{-N}" finds the name of the Nth previous branch we were on, and
1129  *   places the name of the branch in the given buf and returns the
1130  *   number of characters parsed if successful.
1131  *
1132  * - "<branch>@{upstream}" finds the name of the other ref that
1133  *   <branch> is configured to merge with (missing <branch> defaults
1134  *   to the current branch), and places the name of the branch in the
1135  *   given buf and returns the number of characters parsed if
1136  *   successful.
1137  *
1138  * If the input is not of the accepted format, it returns a negative
1139  * number to signal an error.
1140  *
1141  * If the input was ok but there are not N branch switches in the
1142  * reflog, it returns 0.
1143  */
1144 int interpret_branch_name(const char *name, int namelen, struct strbuf *buf)
1145 {
1146         char *at;
1147         const char *start;
1148         int len = interpret_nth_prior_checkout(name, namelen, buf);
1149
1150         if (!namelen)
1151                 namelen = strlen(name);
1152
1153         if (!len) {
1154                 return len; /* syntax Ok, not enough switches */
1155         } else if (len > 0) {
1156                 if (len == namelen)
1157                         return len; /* consumed all */
1158                 else
1159                         return reinterpret(name, namelen, len, buf);
1160         }
1161
1162         for (start = name;
1163              (at = memchr(start, '@', namelen - (start - name)));
1164              start = at + 1) {
1165
1166                 len = interpret_empty_at(name, namelen, at - name, buf);
1167                 if (len > 0)
1168                         return reinterpret(name, namelen, len, buf);
1169
1170                 len = interpret_upstream_mark(name, namelen, at - name, buf);
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  * Many callers know that the user meant to name a commit-ish by
1212  * syntactical positions where the object name appears.  Calling this
1213  * function allows the machinery to disambiguate shorter-than-unique
1214  * abbreviated object names between commit-ish and others.
1215  *
1216  * Note that this does NOT error out when the named object is not a
1217  * commit-ish. It is merely to give a hint to the disambiguation
1218  * machinery.
1219  */
1220 int get_sha1_committish(const char *name, unsigned char *sha1)
1221 {
1222         struct object_context unused;
1223         return get_sha1_with_context(name, GET_SHA1_COMMITTISH,
1224                                      sha1, &unused);
1225 }
1226
1227 int get_sha1_treeish(const char *name, unsigned char *sha1)
1228 {
1229         struct object_context unused;
1230         return get_sha1_with_context(name, GET_SHA1_TREEISH,
1231                                      sha1, &unused);
1232 }
1233
1234 int get_sha1_commit(const char *name, unsigned char *sha1)
1235 {
1236         struct object_context unused;
1237         return get_sha1_with_context(name, GET_SHA1_COMMIT,
1238                                      sha1, &unused);
1239 }
1240
1241 int get_sha1_tree(const char *name, unsigned char *sha1)
1242 {
1243         struct object_context unused;
1244         return get_sha1_with_context(name, GET_SHA1_TREE,
1245                                      sha1, &unused);
1246 }
1247
1248 int get_sha1_blob(const char *name, unsigned char *sha1)
1249 {
1250         struct object_context unused;
1251         return get_sha1_with_context(name, GET_SHA1_BLOB,
1252                                      sha1, &unused);
1253 }
1254
1255 /* Must be called only when object_name:filename doesn't exist. */
1256 static void diagnose_invalid_sha1_path(const char *prefix,
1257                                        const char *filename,
1258                                        const unsigned char *tree_sha1,
1259                                        const char *object_name,
1260                                        int object_name_len)
1261 {
1262         struct stat st;
1263         unsigned char sha1[20];
1264         unsigned mode;
1265
1266         if (!prefix)
1267                 prefix = "";
1268
1269         if (!lstat(filename, &st))
1270                 die("Path '%s' exists on disk, but not in '%.*s'.",
1271                     filename, object_name_len, object_name);
1272         if (errno == ENOENT || errno == ENOTDIR) {
1273                 char *fullname = xmalloc(strlen(filename)
1274                                              + strlen(prefix) + 1);
1275                 strcpy(fullname, prefix);
1276                 strcat(fullname, filename);
1277
1278                 if (!get_tree_entry(tree_sha1, fullname,
1279                                     sha1, &mode)) {
1280                         die("Path '%s' exists, but not '%s'.\n"
1281                             "Did you mean '%.*s:%s' aka '%.*s:./%s'?",
1282                             fullname,
1283                             filename,
1284                             object_name_len, object_name,
1285                             fullname,
1286                             object_name_len, object_name,
1287                             filename);
1288                 }
1289                 die("Path '%s' does not exist in '%.*s'",
1290                     filename, object_name_len, object_name);
1291         }
1292 }
1293
1294 /* Must be called only when :stage:filename doesn't exist. */
1295 static void diagnose_invalid_index_path(int stage,
1296                                         const char *prefix,
1297                                         const char *filename)
1298 {
1299         struct stat st;
1300         const struct cache_entry *ce;
1301         int pos;
1302         unsigned namelen = strlen(filename);
1303         unsigned fullnamelen;
1304         char *fullname;
1305
1306         if (!prefix)
1307                 prefix = "";
1308
1309         /* Wrong stage number? */
1310         pos = cache_name_pos(filename, namelen);
1311         if (pos < 0)
1312                 pos = -pos - 1;
1313         if (pos < active_nr) {
1314                 ce = active_cache[pos];
1315                 if (ce_namelen(ce) == namelen &&
1316                     !memcmp(ce->name, filename, namelen))
1317                         die("Path '%s' is in the index, but not at stage %d.\n"
1318                             "Did you mean ':%d:%s'?",
1319                             filename, stage,
1320                             ce_stage(ce), filename);
1321         }
1322
1323         /* Confusion between relative and absolute filenames? */
1324         fullnamelen = namelen + strlen(prefix);
1325         fullname = xmalloc(fullnamelen + 1);
1326         strcpy(fullname, prefix);
1327         strcat(fullname, filename);
1328         pos = cache_name_pos(fullname, fullnamelen);
1329         if (pos < 0)
1330                 pos = -pos - 1;
1331         if (pos < active_nr) {
1332                 ce = active_cache[pos];
1333                 if (ce_namelen(ce) == fullnamelen &&
1334                     !memcmp(ce->name, fullname, fullnamelen))
1335                         die("Path '%s' is in the index, but not '%s'.\n"
1336                             "Did you mean ':%d:%s' aka ':%d:./%s'?",
1337                             fullname, filename,
1338                             ce_stage(ce), fullname,
1339                             ce_stage(ce), filename);
1340         }
1341
1342         if (!lstat(filename, &st))
1343                 die("Path '%s' exists on disk, but not in the index.", filename);
1344         if (errno == ENOENT || errno == ENOTDIR)
1345                 die("Path '%s' does not exist (neither on disk nor in the index).",
1346                     filename);
1347
1348         free(fullname);
1349 }
1350
1351
1352 static char *resolve_relative_path(const char *rel)
1353 {
1354         if (!starts_with(rel, "./") && !starts_with(rel, "../"))
1355                 return NULL;
1356
1357         if (!startup_info)
1358                 die("BUG: startup_info struct is not initialized.");
1359
1360         if (!is_inside_work_tree())
1361                 die("relative path syntax can't be used outside working tree.");
1362
1363         /* die() inside prefix_path() if resolved path is outside worktree */
1364         return prefix_path(startup_info->prefix,
1365                            startup_info->prefix ? strlen(startup_info->prefix) : 0,
1366                            rel);
1367 }
1368
1369 static int get_sha1_with_context_1(const char *name,
1370                                    unsigned flags,
1371                                    const char *prefix,
1372                                    unsigned char *sha1,
1373                                    struct object_context *oc)
1374 {
1375         int ret, bracket_depth;
1376         int namelen = strlen(name);
1377         const char *cp;
1378         int only_to_die = flags & GET_SHA1_ONLY_TO_DIE;
1379
1380         memset(oc, 0, sizeof(*oc));
1381         oc->mode = S_IFINVALID;
1382         ret = get_sha1_1(name, namelen, sha1, flags);
1383         if (!ret)
1384                 return ret;
1385         /*
1386          * sha1:path --> object name of path in ent sha1
1387          * :path -> object name of absolute path in index
1388          * :./path -> object name of path relative to cwd in index
1389          * :[0-3]:path -> object name of path in index at stage
1390          * :/foo -> recent commit matching foo
1391          */
1392         if (name[0] == ':') {
1393                 int stage = 0;
1394                 const struct cache_entry *ce;
1395                 char *new_path = NULL;
1396                 int pos;
1397                 if (!only_to_die && namelen > 2 && name[1] == '/') {
1398                         struct commit_list *list = NULL;
1399                         for_each_ref(handle_one_ref, &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                 strncpy(oc->path, cp,
1419                         sizeof(oc->path));
1420                 oc->path[sizeof(oc->path)-1] = '\0';
1421
1422                 if (!active_cache)
1423                         read_cache();
1424                 pos = cache_name_pos(cp, namelen);
1425                 if (pos < 0)
1426                         pos = -pos - 1;
1427                 while (pos < active_nr) {
1428                         ce = active_cache[pos];
1429                         if (ce_namelen(ce) != namelen ||
1430                             memcmp(ce->name, cp, namelen))
1431                                 break;
1432                         if (ce_stage(ce) == stage) {
1433                                 hashcpy(sha1, ce->sha1);
1434                                 oc->mode = ce->ce_mode;
1435                                 free(new_path);
1436                                 return 0;
1437                         }
1438                         pos++;
1439                 }
1440                 if (only_to_die && name[1] && name[1] != '/')
1441                         diagnose_invalid_index_path(stage, prefix, cp);
1442                 free(new_path);
1443                 return -1;
1444         }
1445         for (cp = name, bracket_depth = 0; *cp; cp++) {
1446                 if (*cp == '{')
1447                         bracket_depth++;
1448                 else if (bracket_depth && *cp == '}')
1449                         bracket_depth--;
1450                 else if (!bracket_depth && *cp == ':')
1451                         break;
1452         }
1453         if (*cp == ':') {
1454                 unsigned char tree_sha1[20];
1455                 int len = cp - name;
1456                 if (!get_sha1_1(name, len, tree_sha1, GET_SHA1_TREEISH)) {
1457                         const char *filename = cp+1;
1458                         char *new_filename = NULL;
1459
1460                         new_filename = resolve_relative_path(filename);
1461                         if (new_filename)
1462                                 filename = new_filename;
1463                         ret = get_tree_entry(tree_sha1, filename, sha1, &oc->mode);
1464                         if (ret && only_to_die) {
1465                                 diagnose_invalid_sha1_path(prefix, filename,
1466                                                            tree_sha1,
1467                                                            name, len);
1468                         }
1469                         hashcpy(oc->tree, tree_sha1);
1470                         strncpy(oc->path, filename,
1471                                 sizeof(oc->path));
1472                         oc->path[sizeof(oc->path)-1] = '\0';
1473
1474                         free(new_filename);
1475                         return ret;
1476                 } else {
1477                         if (only_to_die)
1478                                 die("Invalid object name '%.*s'.", len, name);
1479                 }
1480         }
1481         return ret;
1482 }
1483
1484 /*
1485  * Call this function when you know "name" given by the end user must
1486  * name an object but it doesn't; the function _may_ die with a better
1487  * diagnostic message than "no such object 'name'", e.g. "Path 'doc' does not
1488  * exist in 'HEAD'" when given "HEAD:doc", or it may return in which case
1489  * you have a chance to diagnose the error further.
1490  */
1491 void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
1492 {
1493         struct object_context oc;
1494         unsigned char sha1[20];
1495         get_sha1_with_context_1(name, GET_SHA1_ONLY_TO_DIE, prefix, sha1, &oc);
1496 }
1497
1498 int get_sha1_with_context(const char *str, unsigned flags, unsigned char *sha1, struct object_context *orc)
1499 {
1500         return get_sha1_with_context_1(str, flags, NULL, sha1, orc);
1501 }