git.oblomov.eu Git - git/blob - sha1_name.c

   1 #include "cache.h"
   2 #include "tag.h"
   3 #include "commit.h"
   4 #include "tree.h"
   5 #include "blob.h"
   6 #include "tree-walk.h"
   7 #include "refs.h"
   8 #include "remote.h"
   9 #include "dir.h"
  10
  11 static int get_sha1_oneline(const char *, unsigned char *, struct commit_list *);
  12
  13 typedef int (*disambiguate_hint_fn)(const unsigned char *, void *);
  14
  15 struct disambiguate_state {
  16         disambiguate_hint_fn fn;
  17         void *cb_data;
  18         unsigned char candidate[20];
  19         unsigned candidate_exists:1;
  20         unsigned candidate_checked:1;
  21         unsigned candidate_ok:1;
  22         unsigned disambiguate_fn_used:1;
  23         unsigned ambiguous:1;
  24         unsigned always_call_fn:1;
  25 };
  26
  27 static void update_candidates(struct disambiguate_state *ds, const unsigned char *current)
  28 {
  29         if (ds->always_call_fn) {
  30                 ds->ambiguous = ds->fn(current, ds->cb_data) ? 1 : 0;
  31                 return;
  32         }
  33         if (!ds->candidate_exists) {
  34                 /* this is the first candidate */
  35                 hashcpy(ds->candidate, current);
  36                 ds->candidate_exists = 1;
  37                 return;
  38         } else if (!hashcmp(ds->candidate, current)) {
  39                 /* the same as what we already have seen */
  40                 return;
  41         }
  42
  43         if (!ds->fn) {
  44                 /* cannot disambiguate between ds->candidate and current */
  45                 ds->ambiguous = 1;
  46                 return;
  47         }
  48
  49         if (!ds->candidate_checked) {
  50                 ds->candidate_ok = ds->fn(ds->candidate, ds->cb_data);
  51                 ds->disambiguate_fn_used = 1;
  52                 ds->candidate_checked = 1;
  53         }
  54
  55         if (!ds->candidate_ok) {
  56                 /* discard the candidate; we know it does not satisfy fn */
  57                 hashcpy(ds->candidate, current);
  58                 ds->candidate_checked = 0;
  59                 return;
  60         }
  61
  62         /* if we reach this point, we know ds->candidate satisfies fn */
  63         if (ds->fn(current, ds->cb_data)) {
  64                 /*
  65                  * if both current and candidate satisfy fn, we cannot
  66                  * disambiguate.
  67                  */
  68                 ds->candidate_ok = 0;
  69                 ds->ambiguous = 1;
  70         }
  71
  72         /* otherwise, current can be discarded and candidate is still good */
  73 }
  74
  75 static void find_short_object_filename(int len, const char *hex_pfx, struct disambiguate_state *ds)
  76 {
  77         struct alternate_object_database *alt;
  78         char hex[40];
  79         static struct alternate_object_database *fakeent;
  80
  81         if (!fakeent) {
  82                 /*
  83                  * Create a "fake" alternate object database that
  84                  * points to our own object database, to make it
  85                  * easier to get a temporary working space in
  86                  * alt->name/alt->base while iterating over the
  87                  * object databases including our own.
  88                  */
  89                 const char *objdir = get_object_directory();
  90                 int objdir_len = strlen(objdir);
  91                 int entlen = objdir_len + 43;
  92                 fakeent = xmalloc(sizeof(*fakeent) + entlen);
  93                 memcpy(fakeent->base, objdir, objdir_len);
  94                 fakeent->name = fakeent->base + objdir_len + 1;
  95                 fakeent->name[-1] = '/';
  96         }
  97         fakeent->next = alt_odb_list;
  98
  99         sprintf(hex, "%.2s", hex_pfx);
 100         for (alt = fakeent; alt && !ds->ambiguous; alt = alt->next) {
 101                 struct dirent *de;
 102                 DIR *dir;
 103                 sprintf(alt->name, "%.2s/", hex_pfx);
 104                 dir = opendir(alt->base);
 105                 if (!dir)
 106                         continue;
 107
 108                 while (!ds->ambiguous && (de = readdir(dir)) != NULL) {
 109                         unsigned char sha1[20];
 110
 111                         if (strlen(de->d_name) != 38)
 112                                 continue;
 113                         if (memcmp(de->d_name, hex_pfx + 2, len - 2))
 114                                 continue;
 115                         memcpy(hex + 2, de->d_name, 38);
 116                         if (!get_sha1_hex(hex, sha1))
 117                                 update_candidates(ds, sha1);
 118                 }
 119                 closedir(dir);
 120         }
 121 }
 122
 123 static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
 124 {
 125         do {
 126                 if (*a != *b)
 127                         return 0;
 128                 a++;
 129                 b++;
 130                 len -= 2;
 131         } while (len > 1);
 132         if (len)
 133                 if ((*a ^ *b) & 0xf0)
 134                         return 0;
 135         return 1;
 136 }
 137
 138 static void unique_in_pack(int len,
 139                           const unsigned char *bin_pfx,
 140                            struct packed_git *p,
 141                            struct disambiguate_state *ds)
 142 {
 143         uint32_t num, last, i, first = 0;
 144         const unsigned char *current = NULL;
 145
 146         open_pack_index(p);
 147         num = p->num_objects;
 148         last = num;
 149         while (first < last) {
 150                 uint32_t mid = (first + last) / 2;
 151                 const unsigned char *current;
 152                 int cmp;
 153
 154                 current = nth_packed_object_sha1(p, mid);
 155                 cmp = hashcmp(bin_pfx, current);
 156                 if (!cmp) {
 157                         first = mid;
 158                         break;
 159                 }
 160                 if (cmp > 0) {
 161                         first = mid+1;
 162                         continue;
 163                 }
 164                 last = mid;
 165         }
 166
 167         /*
 168          * At this point, "first" is the location of the lowest object
 169          * with an object name that could match "bin_pfx".  See if we have
 170          * 0, 1 or more objects that actually match(es).
 171          */
 172         for (i = first; i < num && !ds->ambiguous; i++) {
 173                 current = nth_packed_object_sha1(p, i);
 174                 if (!match_sha(len, bin_pfx, current))
 175                         break;
 176                 update_candidates(ds, current);
 177         }
 178 }
 179
 180 static void find_short_packed_object(int len, const unsigned char *bin_pfx,
 181                                      struct disambiguate_state *ds)
 182 {
 183         struct packed_git *p;
 184
 185         prepare_packed_git();
 186         for (p = packed_git; p && !ds->ambiguous; p = p->next)
 187                 unique_in_pack(len, bin_pfx, p, ds);
 188 }
 189
 190 #define SHORT_NAME_NOT_FOUND (-1)
 191 #define SHORT_NAME_AMBIGUOUS (-2)
 192
 193 static int finish_object_disambiguation(struct disambiguate_state *ds,
 194                                         unsigned char *sha1)
 195 {
 196         if (ds->ambiguous)
 197                 return SHORT_NAME_AMBIGUOUS;
 198
 199         if (!ds->candidate_exists)
 200                 return SHORT_NAME_NOT_FOUND;
 201
 202         if (!ds->candidate_checked)
 203                 /*
 204                  * If this is the only candidate, there is no point
 205                  * calling the disambiguation hint callback.
 206                  *
 207                  * On the other hand, if the current candidate
 208                  * replaced an earlier candidate that did _not_ pass
 209                  * the disambiguation hint callback, then we do have
 210                  * more than one objects that match the short name
 211                  * given, so we should make sure this one matches;
 212                  * otherwise, if we discovered this one and the one
 213                  * that we previously discarded in the reverse order,
 214                  * we would end up showing different results in the
 215                  * same repository!
 216                  */
 217                 ds->candidate_ok = (!ds->disambiguate_fn_used ||
 218                                     ds->fn(ds->candidate, ds->cb_data));
 219
 220         if (!ds->candidate_ok)
 221                 return SHORT_NAME_AMBIGUOUS;
 222
 223         hashcpy(sha1, ds->candidate);
 224         return 0;
 225 }
 226
 227 static int disambiguate_commit_only(const unsigned char *sha1, void *cb_data_unused)
 228 {
 229         int kind = sha1_object_info(sha1, NULL);
 230         return kind == OBJ_COMMIT;
 231 }
 232
 233 static int disambiguate_committish_only(const unsigned char *sha1, void *cb_data_unused)
 234 {
 235         struct object *obj;
 236         int kind;
 237
 238         kind = sha1_object_info(sha1, NULL);
 239         if (kind == OBJ_COMMIT)
 240                 return 1;
 241         if (kind != OBJ_TAG)
 242                 return 0;
 243
 244         /* We need to do this the hard way... */
 245         obj = deref_tag(parse_object(sha1), NULL, 0);
 246         if (obj && obj->type == OBJ_COMMIT)
 247                 return 1;
 248         return 0;
 249 }
 250
 251 static int disambiguate_tree_only(const unsigned char *sha1, void *cb_data_unused)
 252 {
 253         int kind = sha1_object_info(sha1, NULL);
 254         return kind == OBJ_TREE;
 255 }
 256
 257 static int disambiguate_treeish_only(const unsigned char *sha1, void *cb_data_unused)
 258 {
 259         struct object *obj;
 260         int kind;
 261
 262         kind = sha1_object_info(sha1, NULL);
 263         if (kind == OBJ_TREE || kind == OBJ_COMMIT)
 264                 return 1;
 265         if (kind != OBJ_TAG)
 266                 return 0;
 267
 268         /* We need to do this the hard way... */
 269         obj = deref_tag(lookup_object(sha1), NULL, 0);
 270         if (obj && (obj->type == OBJ_TREE || obj->type == OBJ_COMMIT))
 271                 return 1;
 272         return 0;
 273 }
 274
 275 static int disambiguate_blob_only(const unsigned char *sha1, void *cb_data_unused)
 276 {
 277         int kind = sha1_object_info(sha1, NULL);
 278         return kind == OBJ_BLOB;
 279 }
 280
 281 static int prepare_prefixes(const char *name, int len,
 282                             unsigned char *bin_pfx,
 283                             char *hex_pfx)
 284 {
 285         int i;
 286
 287         hashclr(bin_pfx);
 288         memset(hex_pfx, 'x', 40);
 289         for (i = 0; i < len ;i++) {
 290                 unsigned char c = name[i];
 291                 unsigned char val;
 292                 if (c >= '0' && c <= '9')
 293                         val = c - '0';
 294                 else if (c >= 'a' && c <= 'f')
 295                         val = c - 'a' + 10;
 296                 else if (c >= 'A' && c <='F') {
 297                         val = c - 'A' + 10;
 298                         c -= 'A' - 'a';
 299                 }
 300                 else
 301                         return -1;
 302                 hex_pfx[i] = c;
 303                 if (!(i & 1))
 304                         val <<= 4;
 305                 bin_pfx[i >> 1] |= val;
 306         }
 307         return 0;
 308 }
 309
 310 static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 311                           unsigned flags)
 312 {
 313         int status;
 314         char hex_pfx[40];
 315         unsigned char bin_pfx[20];
 316         struct disambiguate_state ds;
 317         int quietly = !!(flags & GET_SHA1_QUIETLY);
 318
 319         if (len < MINIMUM_ABBREV || len > 40)
 320                 return -1;
 321         if (prepare_prefixes(name, len, bin_pfx, hex_pfx) < 0)
 322                 return -1;
 323
 324         prepare_alt_odb();
 325
 326         memset(&ds, 0, sizeof(ds));
 327         if (flags & GET_SHA1_COMMIT)
 328                 ds.fn = disambiguate_commit_only;
 329         else if (flags & GET_SHA1_COMMITTISH)
 330                 ds.fn = disambiguate_committish_only;
 331         else if (flags & GET_SHA1_TREE)
 332                 ds.fn = disambiguate_tree_only;
 333         else if (flags & GET_SHA1_TREEISH)
 334                 ds.fn = disambiguate_treeish_only;
 335         else if (flags & GET_SHA1_BLOB)
 336                 ds.fn = disambiguate_blob_only;
 337
 338         find_short_object_filename(len, hex_pfx, &ds);
 339         find_short_packed_object(len, bin_pfx, &ds);
 340         status = finish_object_disambiguation(&ds, sha1);
 341
 342         if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
 343                 return error("short SHA1 %.*s is ambiguous.", len, hex_pfx);
 344         return status;
 345 }
 346
 347 int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
 348 {
 349         char hex_pfx[40];
 350         unsigned char bin_pfx[20];
 351         struct disambiguate_state ds;
 352         int len = strlen(prefix);
 353
 354         if (len < MINIMUM_ABBREV || len > 40)
 355                 return -1;
 356         if (prepare_prefixes(prefix, len, bin_pfx, hex_pfx) < 0)
 357                 return -1;
 358
 359         prepare_alt_odb();
 360
 361         memset(&ds, 0, sizeof(ds));
 362         ds.always_call_fn = 1;
 363         ds.cb_data = cb_data;
 364         ds.fn = fn;
 365
 366         find_short_object_filename(len, hex_pfx, &ds);
 367         find_short_packed_object(len, bin_pfx, &ds);
 368         return ds.ambiguous;
 369 }
 370
 371 int find_unique_abbrev_r(char *hex, const unsigned char *sha1, int len)
 372 {
 373         int status, exists;
 374
 375         sha1_to_hex_r(hex, sha1);
 376         if (len == 40 || !len)
 377                 return 40;
 378         exists = has_sha1_file(sha1);
 379         while (len < 40) {
 380                 unsigned char sha1_ret[20];
 381                 status = get_short_sha1(hex, len, sha1_ret, GET_SHA1_QUIETLY);
 382                 if (exists
 383                     ? !status
 384                     : status == SHORT_NAME_NOT_FOUND) {
 385                         hex[len] = 0;
 386                         return len;
 387                 }
 388                 len++;
 389         }
 390         return len;
 391 }
 392
 393 const char *find_unique_abbrev(const unsigned char *sha1, int len)
 394 {
 395         static char hex[GIT_SHA1_HEXSZ + 1];
 396         find_unique_abbrev_r(hex, sha1, len);
 397         return hex;
 398 }
 399
 400 static int ambiguous_path(const char *path, int len)
 401 {
 402         int slash = 1;
 403         int cnt;
 404
 405         for (cnt = 0; cnt < len; cnt++) {
 406                 switch (*path++) {
 407                 case '\0':
 408                         break;
 409                 case '/':
 410                         if (slash)
 411                                 break;
 412                         slash = 1;
 413                         continue;
 414                 case '.':
 415                         continue;
 416                 default:
 417                         slash = 0;
 418                         continue;
 419                 }
 420                 break;
 421         }
 422         return slash;
 423 }
 424
 425 static inline int at_mark(const char *string, int len,
 426                           const char **suffix, int nr)
 427 {
 428         int i;
 429
 430         for (i = 0; i < nr; i++) {
 431                 int suffix_len = strlen(suffix[i]);
 432                 if (suffix_len <= len
 433                     && !memcmp(string, suffix[i], suffix_len))
 434                         return suffix_len;
 435         }
 436         return 0;
 437 }
 438
 439 static inline int upstream_mark(const char *string, int len)
 440 {
 441         const char *suffix[] = { "@{upstream}", "@{u}" };
 442         return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
 443 }
 444
 445 static inline int push_mark(const char *string, int len)
 446 {
 447         const char *suffix[] = { "@{push}" };
 448         return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
 449 }
 450
 451 static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags);
 452 static int interpret_nth_prior_checkout(const char *name, int namelen, struct strbuf *buf);
 453
 454 static int get_sha1_basic(const char *str, int len, unsigned char *sha1,
 455                           unsigned int flags)
 456 {
 457         static const char *warn_msg = "refname '%.*s' is ambiguous.";
 458         static const char *object_name_msg = N_(
 459         "Git normally never creates a ref that ends with 40 hex characters\n"
 460         "because it will be ignored when you just specify 40-hex. These refs\n"
 461         "may be created by mistake. For example,\n"
 462         "\n"
 463         "  git checkout -b $br $(git rev-parse ...)\n"
 464         "\n"
 465         "where \"$br\" is somehow empty and a 40-hex ref is created. Please\n"
 466         "examine these refs and maybe delete them. Turn this message off by\n"
 467         "running \"git config advice.objectNameWarning false\"");
 468         unsigned char tmp_sha1[20];
 469         char *real_ref = NULL;
 470         int refs_found = 0;
 471         int at, reflog_len, nth_prior = 0;
 472
 473         if (len == 40 && !get_sha1_hex(str, sha1)) {
 474                 if (warn_ambiguous_refs && warn_on_object_refname_ambiguity) {
 475                         refs_found = dwim_ref(str, len, tmp_sha1, &real_ref);
 476                         if (refs_found > 0) {
 477                                 warning(warn_msg, len, str);
 478                                 if (advice_object_name_warning)
 479                                         fprintf(stderr, "%s\n", _(object_name_msg));
 480                         }
 481                         free(real_ref);
 482                 }
 483                 return 0;
 484         }
 485
 486         /* basic@{time or number or -number} format to query ref-log */
 487         reflog_len = at = 0;
 488         if (len && str[len-1] == '}') {
 489                 for (at = len-4; at >= 0; at--) {
 490                         if (str[at] == '@' && str[at+1] == '{') {
 491                                 if (str[at+2] == '-') {
 492                                         if (at != 0)
 493                                                 /* @{-N} not at start */
 494                                                 return -1;
 495                                         nth_prior = 1;
 496                                         continue;
 497                                 }
 498                                 if (!upstream_mark(str + at, len - at) &&
 499                                     !push_mark(str + at, len - at)) {
 500                                         reflog_len = (len-1) - (at+2);
 501                                         len = at;
 502                                 }
 503                                 break;
 504                         }
 505                 }
 506         }
 507
 508         /* Accept only unambiguous ref paths. */
 509         if (len && ambiguous_path(str, len))
 510                 return -1;
 511
 512         if (nth_prior) {
 513                 struct strbuf buf = STRBUF_INIT;
 514                 int detached;
 515
 516                 if (interpret_nth_prior_checkout(str, len, &buf) > 0) {
 517                         detached = (buf.len == 40 && !get_sha1_hex(buf.buf, sha1));
 518                         strbuf_release(&buf);
 519                         if (detached)
 520                                 return 0;
 521                 }
 522         }
 523
 524         if (!len && reflog_len)
 525                 /* allow "@{...}" to mean the current branch reflog */
 526                 refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
 527         else if (reflog_len)
 528                 refs_found = dwim_log(str, len, sha1, &real_ref);
 529         else
 530                 refs_found = dwim_ref(str, len, sha1, &real_ref);
 531
 532         if (!refs_found)
 533                 return -1;
 534
 535         if (warn_ambiguous_refs && !(flags & GET_SHA1_QUIETLY) &&
 536             (refs_found > 1 ||
 537              !get_short_sha1(str, len, tmp_sha1, GET_SHA1_QUIETLY)))
 538                 warning(warn_msg, len, str);
 539
 540         if (reflog_len) {
 541                 int nth, i;
 542                 unsigned long at_time;
 543                 unsigned long co_time;
 544                 int co_tz, co_cnt;
 545
 546                 /* Is it asking for N-th entry, or approxidate? */
 547                 for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 548                         char ch = str[at+2+i];
 549                         if ('0' <= ch && ch <= '9')
 550                                 nth = nth * 10 + ch - '0';
 551                         else
 552                                 nth = -1;
 553                 }
 554                 if (100000000 <= nth) {
 555                         at_time = nth;
 556                         nth = -1;
 557                 } else if (0 <= nth)
 558                         at_time = 0;
 559                 else {
 560                         int errors = 0;
 561                         char *tmp = xstrndup(str + at + 2, reflog_len);
 562                         at_time = approxidate_careful(tmp, &errors);
 563                         free(tmp);
 564                         if (errors) {
 565                                 free(real_ref);
 566                                 return -1;
 567                         }
 568                 }
 569                 if (read_ref_at(real_ref, flags, at_time, nth, sha1, NULL,
 570                                 &co_time, &co_tz, &co_cnt)) {
 571                         if (!len) {
 572                                 if (starts_with(real_ref, "refs/heads/")) {
 573                                         str = real_ref + 11;
 574                                         len = strlen(real_ref + 11);
 575                                 } else {
 576                                         /* detached HEAD */
 577                                         str = "HEAD";
 578                                         len = 4;
 579                                 }
 580                         }
 581                         if (at_time) {
 582                                 if (!(flags & GET_SHA1_QUIETLY)) {
 583                                         warning("Log for '%.*s' only goes "
 584                                                 "back to %s.", len, str,
 585                                                 show_date(co_time, co_tz, DATE_MODE(RFC2822)));
 586                                 }
 587                         } else {
 588                                 if (flags & GET_SHA1_QUIETLY) {
 589                                         exit(128);
 590                                 }
 591                                 die("Log for '%.*s' only has %d entries.",
 592                                     len, str, co_cnt);
 593                         }
 594                 }
 595         }
 596
 597         free(real_ref);
 598         return 0;
 599 }
 600
 601 static int get_parent(const char *name, int len,
 602                       unsigned char *result, int idx)
 603 {
 604         unsigned char sha1[20];
 605         int ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 606         struct commit *commit;
 607         struct commit_list *p;
 608
 609         if (ret)
 610                 return ret;
 611         commit = lookup_commit_reference(sha1);
 612         if (parse_commit(commit))
 613                 return -1;
 614         if (!idx) {
 615                 hashcpy(result, commit->object.sha1);
 616                 return 0;
 617         }
 618         p = commit->parents;
 619         while (p) {
 620                 if (!--idx) {
 621                         hashcpy(result, p->item->object.sha1);
 622                         return 0;
 623                 }
 624                 p = p->next;
 625         }
 626         return -1;
 627 }
 628
 629 static int get_nth_ancestor(const char *name, int len,
 630                             unsigned char *result, int generation)
 631 {
 632         unsigned char sha1[20];
 633         struct commit *commit;
 634         int ret;
 635
 636         ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 637         if (ret)
 638                 return ret;
 639         commit = lookup_commit_reference(sha1);
 640         if (!commit)
 641                 return -1;
 642
 643         while (generation--) {
 644                 if (parse_commit(commit) || !commit->parents)
 645                         return -1;
 646                 commit = commit->parents->item;
 647         }
 648         hashcpy(result, commit->object.sha1);
 649         return 0;
 650 }
 651
 652 struct object *peel_to_type(const char *name, int namelen,
 653                             struct object *o, enum object_type expected_type)
 654 {
 655         if (name && !namelen)
 656                 namelen = strlen(name);
 657         while (1) {
 658                 if (!o || (!o->parsed && !parse_object(o->sha1)))
 659                         return NULL;
 660                 if (expected_type == OBJ_ANY || o->type == expected_type)
 661                         return o;
 662                 if (o->type == OBJ_TAG)
 663                         o = ((struct tag*) o)->tagged;
 664                 else if (o->type == OBJ_COMMIT)
 665                         o = &(((struct commit *) o)->tree->object);
 666                 else {
 667                         if (name)
 668                                 error("%.*s: expected %s type, but the object "
 669                                       "dereferences to %s type",
 670                                       namelen, name, typename(expected_type),
 671                                       typename(o->type));
 672                         return NULL;
 673                 }
 674         }
 675 }
 676
 677 static int peel_onion(const char *name, int len, unsigned char *sha1)
 678 {
 679         unsigned char outer[20];
 680         const char *sp;
 681         unsigned int expected_type = 0;
 682         unsigned lookup_flags = 0;
 683         struct object *o;
 684
 685         /*
 686          * "ref^{type}" dereferences ref repeatedly until you cannot
 687          * dereference anymore, or you get an object of given type,
 688          * whichever comes first.  "ref^{}" means just dereference
 689          * tags until you get a non-tag.  "ref^0" is a shorthand for
 690          * "ref^{commit}".  "commit^{tree}" could be used to find the
 691          * top-level tree of the given commit.
 692          */
 693         if (len < 4 || name[len-1] != '}')
 694                 return -1;
 695
 696         for (sp = name + len - 1; name <= sp; sp--) {
 697                 int ch = *sp;
 698                 if (ch == '{' && name < sp && sp[-1] == '^')
 699                         break;
 700         }
 701         if (sp <= name)
 702                 return -1;
 703
 704         sp++; /* beginning of type name, or closing brace for empty */
 705         if (starts_with(sp, "commit}"))
 706                 expected_type = OBJ_COMMIT;
 707         else if (starts_with(sp, "tag}"))
 708                 expected_type = OBJ_TAG;
 709         else if (starts_with(sp, "tree}"))
 710                 expected_type = OBJ_TREE;
 711         else if (starts_with(sp, "blob}"))
 712                 expected_type = OBJ_BLOB;
 713         else if (starts_with(sp, "object}"))
 714                 expected_type = OBJ_ANY;
 715         else if (sp[0] == '}')
 716                 expected_type = OBJ_NONE;
 717         else if (sp[0] == '/')
 718                 expected_type = OBJ_COMMIT;
 719         else
 720                 return -1;
 721
 722         if (expected_type == OBJ_COMMIT)
 723                 lookup_flags = GET_SHA1_COMMITTISH;
 724         else if (expected_type == OBJ_TREE)
 725                 lookup_flags = GET_SHA1_TREEISH;
 726
 727         if (get_sha1_1(name, sp - name - 2, outer, lookup_flags))
 728                 return -1;
 729
 730         o = parse_object(outer);
 731         if (!o)
 732                 return -1;
 733         if (!expected_type) {
 734                 o = deref_tag(o, name, sp - name - 2);
 735                 if (!o || (!o->parsed && !parse_object(o->sha1)))
 736                         return -1;
 737                 hashcpy(sha1, o->sha1);
 738                 return 0;
 739         }
 740
 741         /*
 742          * At this point, the syntax look correct, so
 743          * if we do not get the needed object, we should
 744          * barf.
 745          */
 746         o = peel_to_type(name, len, o, expected_type);
 747         if (!o)
 748                 return -1;
 749
 750         hashcpy(sha1, o->sha1);
 751         if (sp[0] == '/') {
 752                 /* "$commit^{/foo}" */
 753                 char *prefix;
 754                 int ret;
 755                 struct commit_list *list = NULL;
 756
 757                 /*
 758                  * $commit^{/}. Some regex implementation may reject.
 759                  * We don't need regex anyway. '' pattern always matches.
 760                  */
 761                 if (sp[1] == '}')
 762                         return 0;
 763
 764                 prefix = xstrndup(sp + 1, name + len - 1 - (sp + 1));
 765                 commit_list_insert((struct commit *)o, &list);
 766                 ret = get_sha1_oneline(prefix, sha1, list);
 767                 free(prefix);
 768                 return ret;
 769         }
 770         return 0;
 771 }
 772
 773 static int get_describe_name(const char *name, int len, unsigned char *sha1)
 774 {
 775         const char *cp;
 776         unsigned flags = GET_SHA1_QUIETLY | GET_SHA1_COMMIT;
 777
 778         for (cp = name + len - 1; name + 2 <= cp; cp--) {
 779                 char ch = *cp;
 780                 if (!isxdigit(ch)) {
 781                         /* We must be looking at g in "SOMETHING-g"
 782                          * for it to be describe output.
 783                          */
 784                         if (ch == 'g' && cp[-1] == '-') {
 785                                 cp++;
 786                                 len -= cp - name;
 787                                 return get_short_sha1(cp, len, sha1, flags);
 788                         }
 789                 }
 790         }
 791         return -1;
 792 }
 793
 794 static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags)
 795 {
 796         int ret, has_suffix;
 797         const char *cp;
 798
 799         /*
 800          * "name~3" is "name^^^", "name~" is "name~1", and "name^" is "name^1".
 801          */
 802         has_suffix = 0;
 803         for (cp = name + len - 1; name <= cp; cp--) {
 804                 int ch = *cp;
 805                 if ('0' <= ch && ch <= '9')
 806                         continue;
 807                 if (ch == '~' || ch == '^')
 808                         has_suffix = ch;
 809                 break;
 810         }
 811
 812         if (has_suffix) {
 813                 int num = 0;
 814                 int len1 = cp - name;
 815                 cp++;
 816                 while (cp < name + len)
 817                         num = num * 10 + *cp++ - '0';
 818                 if (!num && len1 == len - 1)
 819                         num = 1;
 820                 if (has_suffix == '^')
 821                         return get_parent(name, len1, sha1, num);
 822                 /* else if (has_suffix == '~') -- goes without saying */
 823                 return get_nth_ancestor(name, len1, sha1, num);
 824         }
 825
 826         ret = peel_onion(name, len, sha1);
 827         if (!ret)
 828                 return 0;
 829
 830         ret = get_sha1_basic(name, len, sha1, lookup_flags);
 831         if (!ret)
 832                 return 0;
 833
 834         /* It could be describe output that is "SOMETHING-gXXXX" */
 835         ret = get_describe_name(name, len, sha1);
 836         if (!ret)
 837                 return 0;
 838
 839         return get_short_sha1(name, len, sha1, lookup_flags);
 840 }
 841
 842 /*
 843  * This interprets names like ':/Initial revision of "git"' by searching
 844  * through history and returning the first commit whose message starts
 845  * the given regular expression.
 846  *
 847  * For future extension, ':/!' is reserved. If you want to match a message
 848  * beginning with a '!', you have to repeat the exclamation mark.
 849  */
 850
 851 /* Remember to update object flag allocation in object.h */
 852 #define ONELINE_SEEN (1u<<20)
 853
 854 static int handle_one_ref(const char *path, const struct object_id *oid,
 855                           int flag, void *cb_data)
 856 {
 857         struct commit_list **list = cb_data;
 858         struct object *object = parse_object(oid->hash);
 859         if (!object)
 860                 return 0;
 861         if (object->type == OBJ_TAG) {
 862                 object = deref_tag(object, path, strlen(path));
 863                 if (!object)
 864                         return 0;
 865         }
 866         if (object->type != OBJ_COMMIT)
 867                 return 0;
 868         commit_list_insert((struct commit *)object, list);
 869         return 0;
 870 }
 871
 872 static int get_sha1_oneline(const char *prefix, unsigned char *sha1,
 873                             struct commit_list *list)
 874 {
 875         struct commit_list *backup = NULL, *l;
 876         int found = 0;
 877         regex_t regex;
 878
 879         if (prefix[0] == '!') {
 880                 if (prefix[1] != '!')
 881                         die ("Invalid search pattern: %s", prefix);
 882                 prefix++;
 883         }
 884
 885         if (regcomp(&regex, prefix, REG_EXTENDED))
 886                 die("Invalid search pattern: %s", prefix);
 887
 888         for (l = list; l; l = l->next) {
 889                 l->item->object.flags |= ONELINE_SEEN;
 890                 commit_list_insert(l->item, &backup);
 891         }
 892         while (list) {
 893                 const char *p, *buf;
 894                 struct commit *commit;
 895                 int matches;
 896
 897                 commit = pop_most_recent_commit(&list, ONELINE_SEEN);
 898                 if (!parse_object(commit->object.sha1))
 899                         continue;
 900                 buf = get_commit_buffer(commit, NULL);
 901                 p = strstr(buf, "\n\n");
 902                 matches = p && !regexec(&regex, p + 2, 0, NULL, 0);
 903                 unuse_commit_buffer(commit, buf);
 904
 905                 if (matches) {
 906                         hashcpy(sha1, commit->object.sha1);
 907                         found = 1;
 908                         break;
 909                 }
 910         }
 911         regfree(&regex);
 912         free_commit_list(list);
 913         for (l = backup; l; l = l->next)
 914                 clear_commit_marks(l->item, ONELINE_SEEN);
 915         free_commit_list(backup);
 916         return found ? 0 : -1;
 917 }
 918
 919 struct grab_nth_branch_switch_cbdata {
 920         int remaining;
 921         struct strbuf buf;
 922 };
 923
 924 static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
 925                                   const char *email, unsigned long timestamp, int tz,
 926                                   const char *message, void *cb_data)
 927 {
 928         struct grab_nth_branch_switch_cbdata *cb = cb_data;
 929         const char *match = NULL, *target = NULL;
 930         size_t len;
 931
 932         if (skip_prefix(message, "checkout: moving from ", &match))
 933                 target = strstr(match, " to ");
 934
 935         if (!match || !target)
 936                 return 0;
 937         if (--(cb->remaining) == 0) {
 938                 len = target - match;
 939                 strbuf_reset(&cb->buf);
 940                 strbuf_add(&cb->buf, match, len);
 941                 return 1; /* we are done */
 942         }
 943         return 0;
 944 }
 945
 946 /*
 947  * Parse @{-N} syntax, return the number of characters parsed
 948  * if successful; otherwise signal an error with negative value.
 949  */
 950 static int interpret_nth_prior_checkout(const char *name, int namelen,
 951                                         struct strbuf *buf)
 952 {
 953         long nth;
 954         int retval;
 955         struct grab_nth_branch_switch_cbdata cb;
 956         const char *brace;
 957         char *num_end;
 958
 959         if (namelen < 4)
 960                 return -1;
 961         if (name[0] != '@' || name[1] != '{' || name[2] != '-')
 962                 return -1;
 963         brace = memchr(name, '}', namelen);
 964         if (!brace)
 965                 return -1;
 966         nth = strtol(name + 3, &num_end, 10);
 967         if (num_end != brace)
 968                 return -1;
 969         if (nth <= 0)
 970                 return -1;
 971         cb.remaining = nth;
 972         strbuf_init(&cb.buf, 20);
 973
 974         retval = 0;
 975         if (0 < for_each_reflog_ent_reverse("HEAD", grab_nth_branch_switch, &cb)) {
 976                 strbuf_reset(buf);
 977                 strbuf_addbuf(buf, &cb.buf);
 978                 retval = brace - name + 1;
 979         }
 980
 981         strbuf_release(&cb.buf);
 982         return retval;
 983 }
 984
 985 int get_sha1_mb(const char *name, unsigned char *sha1)
 986 {
 987         struct commit *one, *two;
 988         struct commit_list *mbs;
 989         unsigned char sha1_tmp[20];
 990         const char *dots;
 991         int st;
 992
 993         dots = strstr(name, "...");
 994         if (!dots)
 995                 return get_sha1(name, sha1);
 996         if (dots == name)
 997                 st = get_sha1("HEAD", sha1_tmp);
 998         else {
 999                 struct strbuf sb;
1000                 strbuf_init(&sb, dots - name);
1001                 strbuf_add(&sb, name, dots - name);
1002                 st = get_sha1_committish(sb.buf, sha1_tmp);
1003                 strbuf_release(&sb);
1004         }
1005         if (st)
1006                 return st;
1007         one = lookup_commit_reference_gently(sha1_tmp, 0);
1008         if (!one)
1009                 return -1;
1010
1011         if (get_sha1_committish(dots[3] ? (dots + 3) : "HEAD", sha1_tmp))
1012                 return -1;
1013         two = lookup_commit_reference_gently(sha1_tmp, 0);
1014         if (!two)
1015                 return -1;
1016         mbs = get_merge_bases(one, two);
1017         if (!mbs || mbs->next)
1018                 st = -1;
1019         else {
1020                 st = 0;
1021                 hashcpy(sha1, mbs->item->object.sha1);
1022         }
1023         free_commit_list(mbs);
1024         return st;
1025 }
1026
1027 /* parse @something syntax, when 'something' is not {.*} */
1028 static int interpret_empty_at(const char *name, int namelen, int len, struct strbuf *buf)
1029 {
1030         const char *next;
1031
1032         if (len || name[1] == '{')
1033                 return -1;
1034
1035         /* make sure it's a single @, or @@{.*}, not @foo */
1036         next = memchr(name + len + 1, '@', namelen - len - 1);
1037         if (next && next[1] != '{')
1038                 return -1;
1039         if (!next)
1040                 next = name + namelen;
1041         if (next != name + 1)
1042                 return -1;
1043
1044         strbuf_reset(buf);
1045         strbuf_add(buf, "HEAD", 4);
1046         return 1;
1047 }
1048
1049 static int reinterpret(const char *name, int namelen, int len, struct strbuf *buf)
1050 {
1051         /* we have extra data, which might need further processing */
1052         struct strbuf tmp = STRBUF_INIT;
1053         int used = buf->len;
1054         int ret;
1055
1056         strbuf_add(buf, name + len, namelen - len);
1057         ret = interpret_branch_name(buf->buf, buf->len, &tmp);
1058         /* that data was not interpreted, remove our cruft */
1059         if (ret < 0) {
1060                 strbuf_setlen(buf, used);
1061                 return len;
1062         }
1063         strbuf_reset(buf);
1064         strbuf_addbuf(buf, &tmp);
1065         strbuf_release(&tmp);
1066         /* tweak for size of {-N} versus expanded ref name */
1067         return ret - used + len;
1068 }
1069
1070 static void set_shortened_ref(struct strbuf *buf, const char *ref)
1071 {
1072         char *s = shorten_unambiguous_ref(ref, 0);
1073         strbuf_reset(buf);
1074         strbuf_addstr(buf, s);
1075         free(s);
1076 }
1077
1078 static int interpret_branch_mark(const char *name, int namelen,
1079                                  int at, struct strbuf *buf,
1080                                  int (*get_mark)(const char *, int),
1081                                  const char *(*get_data)(struct branch *,
1082                                                          struct strbuf *))
1083 {
1084         int len;
1085         struct branch *branch;
1086         struct strbuf err = STRBUF_INIT;
1087         const char *value;
1088
1089         len = get_mark(name + at, namelen - at);
1090         if (!len)
1091                 return -1;
1092
1093         if (memchr(name, ':', at))
1094                 return -1;
1095
1096         if (at) {
1097                 char *name_str = xmemdupz(name, at);
1098                 branch = branch_get(name_str);
1099                 free(name_str);
1100         } else
1101                 branch = branch_get(NULL);
1102
1103         value = get_data(branch, &err);
1104         if (!value)
1105                 die("%s", err.buf);
1106
1107         set_shortened_ref(buf, value);
1108         return len + at;
1109 }
1110
1111 /*
1112  * This reads short-hand syntax that not only evaluates to a commit
1113  * object name, but also can act as if the end user spelled the name
1114  * of the branch from the command line.
1115  *
1116  * - "@{-N}" finds the name of the Nth previous branch we were on, and
1117  *   places the name of the branch in the given buf and returns the
1118  *   number of characters parsed if successful.
1119  *
1120  * - "<branch>@{upstream}" finds the name of the other ref that
1121  *   <branch> is configured to merge with (missing <branch> defaults
1122  *   to the current branch), and places the name of the branch in the
1123  *   given buf and returns the number of characters parsed if
1124  *   successful.
1125  *
1126  * If the input is not of the accepted format, it returns a negative
1127  * number to signal an error.
1128  *
1129  * If the input was ok but there are not N branch switches in the
1130  * reflog, it returns 0.
1131  */
1132 int interpret_branch_name(const char *name, int namelen, struct strbuf *buf)
1133 {
1134         char *at;
1135         const char *start;
1136         int len = interpret_nth_prior_checkout(name, namelen, buf);
1137
1138         if (!namelen)
1139                 namelen = strlen(name);
1140
1141         if (!len) {
1142                 return len; /* syntax Ok, not enough switches */
1143         } else if (len > 0) {
1144                 if (len == namelen)
1145                         return len; /* consumed all */
1146                 else
1147                         return reinterpret(name, namelen, len, buf);
1148         }
1149
1150         for (start = name;
1151              (at = memchr(start, '@', namelen - (start - name)));
1152              start = at + 1) {
1153
1154                 len = interpret_empty_at(name, namelen, at - name, buf);
1155                 if (len > 0)
1156                         return reinterpret(name, namelen, len, buf);
1157
1158                 len = interpret_branch_mark(name, namelen, at - name, buf,
1159                                             upstream_mark, branch_get_upstream);
1160                 if (len > 0)
1161                         return len;
1162
1163                 len = interpret_branch_mark(name, namelen, at - name, buf,
1164                                             push_mark, branch_get_push);
1165                 if (len > 0)
1166                         return len;
1167         }
1168
1169         return -1;
1170 }
1171
1172 int strbuf_branchname(struct strbuf *sb, const char *name)
1173 {
1174         int len = strlen(name);
1175         int used = interpret_branch_name(name, len, sb);
1176
1177         if (used == len)
1178                 return 0;
1179         if (used < 0)
1180                 used = 0;
1181         strbuf_add(sb, name + used, len - used);
1182         return len;
1183 }
1184
1185 int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
1186 {
1187         strbuf_branchname(sb, name);
1188         if (name[0] == '-')
1189                 return -1;
1190         strbuf_splice(sb, 0, 0, "refs/heads/", 11);
1191         return check_refname_format(sb->buf, 0);
1192 }
1193
1194 /*
1195  * This is like "get_sha1_basic()", except it allows "sha1 expressions",
1196  * notably "xyz^" for "parent of xyz"
1197  */
1198 int get_sha1(const char *name, unsigned char *sha1)
1199 {
1200         struct object_context unused;
1201         return get_sha1_with_context(name, 0, sha1, &unused);
1202 }
1203
1204 /*
1205  * Many callers know that the user meant to name a commit-ish by
1206  * syntactical positions where the object name appears.  Calling this
1207  * function allows the machinery to disambiguate shorter-than-unique
1208  * abbreviated object names between commit-ish and others.
1209  *
1210  * Note that this does NOT error out when the named object is not a
1211  * commit-ish. It is merely to give a hint to the disambiguation
1212  * machinery.
1213  */
1214 int get_sha1_committish(const char *name, unsigned char *sha1)
1215 {
1216         struct object_context unused;
1217         return get_sha1_with_context(name, GET_SHA1_COMMITTISH,
1218                                      sha1, &unused);
1219 }
1220
1221 int get_sha1_treeish(const char *name, unsigned char *sha1)
1222 {
1223         struct object_context unused;
1224         return get_sha1_with_context(name, GET_SHA1_TREEISH,
1225                                      sha1, &unused);
1226 }
1227
1228 int get_sha1_commit(const char *name, unsigned char *sha1)
1229 {
1230         struct object_context unused;
1231         return get_sha1_with_context(name, GET_SHA1_COMMIT,
1232                                      sha1, &unused);
1233 }
1234
1235 int get_sha1_tree(const char *name, unsigned char *sha1)
1236 {
1237         struct object_context unused;
1238         return get_sha1_with_context(name, GET_SHA1_TREE,
1239                                      sha1, &unused);
1240 }
1241
1242 int get_sha1_blob(const char *name, unsigned char *sha1)
1243 {
1244         struct object_context unused;
1245         return get_sha1_with_context(name, GET_SHA1_BLOB,
1246                                      sha1, &unused);
1247 }
1248
1249 /* Must be called only when object_name:filename doesn't exist. */
1250 static void diagnose_invalid_sha1_path(const char *prefix,
1251                                        const char *filename,
1252                                        const unsigned char *tree_sha1,
1253                                        const char *object_name,
1254                                        int object_name_len)
1255 {
1256         unsigned char sha1[20];
1257         unsigned mode;
1258
1259         if (!prefix)
1260                 prefix = "";
1261
1262         if (file_exists(filename))
1263                 die("Path '%s' exists on disk, but not in '%.*s'.",
1264                     filename, object_name_len, object_name);
1265         if (errno == ENOENT || errno == ENOTDIR) {
1266                 char *fullname = xstrfmt("%s%s", prefix, filename);
1267
1268                 if (!get_tree_entry(tree_sha1, fullname,
1269                                     sha1, &mode)) {
1270                         die("Path '%s' exists, but not '%s'.\n"
1271                             "Did you mean '%.*s:%s' aka '%.*s:./%s'?",
1272                             fullname,
1273                             filename,
1274                             object_name_len, object_name,
1275                             fullname,
1276                             object_name_len, object_name,
1277                             filename);
1278                 }
1279                 die("Path '%s' does not exist in '%.*s'",
1280                     filename, object_name_len, object_name);
1281         }
1282 }
1283
1284 /* Must be called only when :stage:filename doesn't exist. */
1285 static void diagnose_invalid_index_path(int stage,
1286                                         const char *prefix,
1287                                         const char *filename)
1288 {
1289         const struct cache_entry *ce;
1290         int pos;
1291         unsigned namelen = strlen(filename);
1292         unsigned fullnamelen;
1293         char *fullname;
1294
1295         if (!prefix)
1296                 prefix = "";
1297
1298         /* Wrong stage number? */
1299         pos = cache_name_pos(filename, namelen);
1300         if (pos < 0)
1301                 pos = -pos - 1;
1302         if (pos < active_nr) {
1303                 ce = active_cache[pos];
1304                 if (ce_namelen(ce) == namelen &&
1305                     !memcmp(ce->name, filename, namelen))
1306                         die("Path '%s' is in the index, but not at stage %d.\n"
1307                             "Did you mean ':%d:%s'?",
1308                             filename, stage,
1309                             ce_stage(ce), filename);
1310         }
1311
1312         /* Confusion between relative and absolute filenames? */
1313         fullnamelen = namelen + strlen(prefix);
1314         fullname = xmalloc(fullnamelen + 1);
1315         strcpy(fullname, prefix);
1316         strcat(fullname, filename);
1317         pos = cache_name_pos(fullname, fullnamelen);
1318         if (pos < 0)
1319                 pos = -pos - 1;
1320         if (pos < active_nr) {
1321                 ce = active_cache[pos];
1322                 if (ce_namelen(ce) == fullnamelen &&
1323                     !memcmp(ce->name, fullname, fullnamelen))
1324                         die("Path '%s' is in the index, but not '%s'.\n"
1325                             "Did you mean ':%d:%s' aka ':%d:./%s'?",
1326                             fullname, filename,
1327                             ce_stage(ce), fullname,
1328                             ce_stage(ce), filename);
1329         }
1330
1331         if (file_exists(filename))
1332                 die("Path '%s' exists on disk, but not in the index.", filename);
1333         if (errno == ENOENT || errno == ENOTDIR)
1334                 die("Path '%s' does not exist (neither on disk nor in the index).",
1335                     filename);
1336
1337         free(fullname);
1338 }
1339
1340
1341 static char *resolve_relative_path(const char *rel)
1342 {
1343         if (!starts_with(rel, "./") && !starts_with(rel, "../"))
1344                 return NULL;
1345
1346         if (!startup_info)
1347                 die("BUG: startup_info struct is not initialized.");
1348
1349         if (!is_inside_work_tree())
1350                 die("relative path syntax can't be used outside working tree.");
1351
1352         /* die() inside prefix_path() if resolved path is outside worktree */
1353         return prefix_path(startup_info->prefix,
1354                            startup_info->prefix ? strlen(startup_info->prefix) : 0,
1355                            rel);
1356 }
1357
1358 static int get_sha1_with_context_1(const char *name,
1359                                    unsigned flags,
1360                                    const char *prefix,
1361                                    unsigned char *sha1,
1362                                    struct object_context *oc)
1363 {
1364         int ret, bracket_depth;
1365         int namelen = strlen(name);
1366         const char *cp;
1367         int only_to_die = flags & GET_SHA1_ONLY_TO_DIE;
1368
1369         memset(oc, 0, sizeof(*oc));
1370         oc->mode = S_IFINVALID;
1371         ret = get_sha1_1(name, namelen, sha1, flags);
1372         if (!ret)
1373                 return ret;
1374         /*
1375          * sha1:path --> object name of path in ent sha1
1376          * :path -> object name of absolute path in index
1377          * :./path -> object name of path relative to cwd in index
1378          * :[0-3]:path -> object name of path in index at stage
1379          * :/foo -> recent commit matching foo
1380          */
1381         if (name[0] == ':') {
1382                 int stage = 0;
1383                 const struct cache_entry *ce;
1384                 char *new_path = NULL;
1385                 int pos;
1386                 if (!only_to_die && namelen > 2 && name[1] == '/') {
1387                         struct commit_list *list = NULL;
1388
1389                         for_each_ref(handle_one_ref, &list);
1390                         commit_list_sort_by_date(&list);
1391                         return get_sha1_oneline(name + 2, sha1, list);
1392                 }
1393                 if (namelen < 3 ||
1394                     name[2] != ':' ||
1395                     name[1] < '0' || '3' < name[1])
1396                         cp = name + 1;
1397                 else {
1398                         stage = name[1] - '0';
1399                         cp = name + 3;
1400                 }
1401                 new_path = resolve_relative_path(cp);
1402                 if (!new_path) {
1403                         namelen = namelen - (cp - name);
1404                 } else {
1405                         cp = new_path;
1406                         namelen = strlen(cp);
1407                 }
1408
1409                 strlcpy(oc->path, cp, sizeof(oc->path));
1410
1411                 if (!active_cache)
1412                         read_cache();
1413                 pos = cache_name_pos(cp, namelen);
1414                 if (pos < 0)
1415                         pos = -pos - 1;
1416                 while (pos < active_nr) {
1417                         ce = active_cache[pos];
1418                         if (ce_namelen(ce) != namelen ||
1419                             memcmp(ce->name, cp, namelen))
1420                                 break;
1421                         if (ce_stage(ce) == stage) {
1422                                 hashcpy(sha1, ce->sha1);
1423                                 oc->mode = ce->ce_mode;
1424                                 free(new_path);
1425                                 return 0;
1426                         }
1427                         pos++;
1428                 }
1429                 if (only_to_die && name[1] && name[1] != '/')
1430                         diagnose_invalid_index_path(stage, prefix, cp);
1431                 free(new_path);
1432                 return -1;
1433         }
1434         for (cp = name, bracket_depth = 0; *cp; cp++) {
1435                 if (*cp == '{')
1436                         bracket_depth++;
1437                 else if (bracket_depth && *cp == '}')
1438                         bracket_depth--;
1439                 else if (!bracket_depth && *cp == ':')
1440                         break;
1441         }
1442         if (*cp == ':') {
1443                 unsigned char tree_sha1[20];
1444                 int len = cp - name;
1445                 if (!get_sha1_1(name, len, tree_sha1, GET_SHA1_TREEISH)) {
1446                         const char *filename = cp+1;
1447                         char *new_filename = NULL;
1448
1449                         new_filename = resolve_relative_path(filename);
1450                         if (new_filename)
1451                                 filename = new_filename;
1452                         if (flags & GET_SHA1_FOLLOW_SYMLINKS) {
1453                                 ret = get_tree_entry_follow_symlinks(tree_sha1,
1454                                         filename, sha1, &oc->symlink_path,
1455                                         &oc->mode);
1456                         } else {
1457                                 ret = get_tree_entry(tree_sha1, filename,
1458                                                      sha1, &oc->mode);
1459                                 if (ret && only_to_die) {
1460                                         diagnose_invalid_sha1_path(prefix,
1461                                                                    filename,
1462                                                                    tree_sha1,
1463                                                                    name, len);
1464                                 }
1465                         }
1466                         hashcpy(oc->tree, tree_sha1);
1467                         strlcpy(oc->path, filename, sizeof(oc->path));
1468
1469                         free(new_filename);
1470                         return ret;
1471                 } else {
1472                         if (only_to_die)
1473                                 die("Invalid object name '%.*s'.", len, name);
1474                 }
1475         }
1476         return ret;
1477 }
1478
1479 /*
1480  * Call this function when you know "name" given by the end user must
1481  * name an object but it doesn't; the function _may_ die with a better
1482  * diagnostic message than "no such object 'name'", e.g. "Path 'doc' does not
1483  * exist in 'HEAD'" when given "HEAD:doc", or it may return in which case
1484  * you have a chance to diagnose the error further.
1485  */
1486 void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
1487 {
1488         struct object_context oc;
1489         unsigned char sha1[20];
1490         get_sha1_with_context_1(name, GET_SHA1_ONLY_TO_DIE, prefix, sha1, &oc);
1491 }
1492
1493 int get_sha1_with_context(const char *str, unsigned flags, unsigned char *sha1, struct object_context *orc)
1494 {
1495         if (flags & GET_SHA1_FOLLOW_SYMLINKS && flags & GET_SHA1_ONLY_TO_DIE)
1496                 die("BUG: incompatible flags for get_sha1_with_context");
1497         return get_sha1_with_context_1(str, flags, NULL, sha1, orc);
1498 }