git.oblomov.eu Git - git/blob - sha1-name.c

   1 #include "cache.h"
   2 #include "config.h"
   3 #include "tag.h"
   4 #include "commit.h"
   5 #include "tree.h"
   6 #include "blob.h"
   7 #include "tree-walk.h"
   8 #include "refs.h"
   9 #include "remote.h"
  10 #include "dir.h"
  11 #include "sha1-array.h"
  12 #include "packfile.h"
  13 #include "object-store.h"
  14 #include "repository.h"
  15
  16 static int get_oid_oneline(const char *, struct object_id *, struct commit_list *);
  17
  18 typedef int (*disambiguate_hint_fn)(const struct object_id *, void *);
  19
  20 struct disambiguate_state {
  21         int len; /* length of prefix in hex chars */
  22         char hex_pfx[GIT_MAX_HEXSZ + 1];
  23         struct object_id bin_pfx;
  24
  25         disambiguate_hint_fn fn;
  26         void *cb_data;
  27         struct object_id candidate;
  28         unsigned candidate_exists:1;
  29         unsigned candidate_checked:1;
  30         unsigned candidate_ok:1;
  31         unsigned disambiguate_fn_used:1;
  32         unsigned ambiguous:1;
  33         unsigned always_call_fn:1;
  34 };
  35
  36 static void update_candidates(struct disambiguate_state *ds, const struct object_id *current)
  37 {
  38         if (ds->always_call_fn) {
  39                 ds->ambiguous = ds->fn(current, ds->cb_data) ? 1 : 0;
  40                 return;
  41         }
  42         if (!ds->candidate_exists) {
  43                 /* this is the first candidate */
  44                 oidcpy(&ds->candidate, current);
  45                 ds->candidate_exists = 1;
  46                 return;
  47         } else if (!oidcmp(&ds->candidate, current)) {
  48                 /* the same as what we already have seen */
  49                 return;
  50         }
  51
  52         if (!ds->fn) {
  53                 /* cannot disambiguate between ds->candidate and current */
  54                 ds->ambiguous = 1;
  55                 return;
  56         }
  57
  58         if (!ds->candidate_checked) {
  59                 ds->candidate_ok = ds->fn(&ds->candidate, ds->cb_data);
  60                 ds->disambiguate_fn_used = 1;
  61                 ds->candidate_checked = 1;
  62         }
  63
  64         if (!ds->candidate_ok) {
  65                 /* discard the candidate; we know it does not satisfy fn */
  66                 oidcpy(&ds->candidate, current);
  67                 ds->candidate_checked = 0;
  68                 return;
  69         }
  70
  71         /* if we reach this point, we know ds->candidate satisfies fn */
  72         if (ds->fn(current, ds->cb_data)) {
  73                 /*
  74                  * if both current and candidate satisfy fn, we cannot
  75                  * disambiguate.
  76                  */
  77                 ds->candidate_ok = 0;
  78                 ds->ambiguous = 1;
  79         }
  80
  81         /* otherwise, current can be discarded and candidate is still good */
  82 }
  83
  84 static int append_loose_object(const struct object_id *oid, const char *path,
  85                                void *data)
  86 {
  87         oid_array_append(data, oid);
  88         return 0;
  89 }
  90
  91 static int match_sha(unsigned, const unsigned char *, const unsigned char *);
  92
  93 static void find_short_object_filename(struct disambiguate_state *ds)
  94 {
  95         int subdir_nr = ds->bin_pfx.hash[0];
  96         struct alternate_object_database *alt;
  97         static struct alternate_object_database *fakeent;
  98
  99         if (!fakeent) {
 100                 /*
 101                  * Create a "fake" alternate object database that
 102                  * points to our own object database, to make it
 103                  * easier to get a temporary working space in
 104                  * alt->name/alt->base while iterating over the
 105                  * object databases including our own.
 106                  */
 107                 fakeent = alloc_alt_odb(get_object_directory());
 108         }
 109         fakeent->next = the_repository->objects->alt_odb_list;
 110
 111         for (alt = fakeent; alt && !ds->ambiguous; alt = alt->next) {
 112                 int pos;
 113
 114                 if (!alt->loose_objects_subdir_seen[subdir_nr]) {
 115                         struct strbuf *buf = alt_scratch_buf(alt);
 116                         for_each_file_in_obj_subdir(subdir_nr, buf,
 117                                                     append_loose_object,
 118                                                     NULL, NULL,
 119                                                     &alt->loose_objects_cache);
 120                         alt->loose_objects_subdir_seen[subdir_nr] = 1;
 121                 }
 122
 123                 pos = oid_array_lookup(&alt->loose_objects_cache, &ds->bin_pfx);
 124                 if (pos < 0)
 125                         pos = -1 - pos;
 126                 while (!ds->ambiguous && pos < alt->loose_objects_cache.nr) {
 127                         const struct object_id *oid;
 128                         oid = alt->loose_objects_cache.oid + pos;
 129                         if (!match_sha(ds->len, ds->bin_pfx.hash, oid->hash))
 130                                 break;
 131                         update_candidates(ds, oid);
 132                         pos++;
 133                 }
 134         }
 135 }
 136
 137 static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
 138 {
 139         do {
 140                 if (*a != *b)
 141                         return 0;
 142                 a++;
 143                 b++;
 144                 len -= 2;
 145         } while (len > 1);
 146         if (len)
 147                 if ((*a ^ *b) & 0xf0)
 148                         return 0;
 149         return 1;
 150 }
 151
 152 static void unique_in_pack(struct packed_git *p,
 153                            struct disambiguate_state *ds)
 154 {
 155         uint32_t num, i, first = 0;
 156         const struct object_id *current = NULL;
 157
 158         if (open_pack_index(p) || !p->num_objects)
 159                 return;
 160
 161         num = p->num_objects;
 162         bsearch_pack(&ds->bin_pfx, p, &first);
 163
 164         /*
 165          * At this point, "first" is the location of the lowest object
 166          * with an object name that could match "bin_pfx".  See if we have
 167          * 0, 1 or more objects that actually match(es).
 168          */
 169         for (i = first; i < num && !ds->ambiguous; i++) {
 170                 struct object_id oid;
 171                 current = nth_packed_object_oid(&oid, p, i);
 172                 if (!match_sha(ds->len, ds->bin_pfx.hash, current->hash))
 173                         break;
 174                 update_candidates(ds, current);
 175         }
 176 }
 177
 178 static void find_short_packed_object(struct disambiguate_state *ds)
 179 {
 180         struct packed_git *p;
 181
 182         for (p = get_packed_git(the_repository); p && !ds->ambiguous;
 183              p = p->next)
 184                 unique_in_pack(p, ds);
 185 }
 186
 187 #define SHORT_NAME_NOT_FOUND (-1)
 188 #define SHORT_NAME_AMBIGUOUS (-2)
 189
 190 static int finish_object_disambiguation(struct disambiguate_state *ds,
 191                                         struct object_id *oid)
 192 {
 193         if (ds->ambiguous)
 194                 return SHORT_NAME_AMBIGUOUS;
 195
 196         if (!ds->candidate_exists)
 197                 return SHORT_NAME_NOT_FOUND;
 198
 199         if (!ds->candidate_checked)
 200                 /*
 201                  * If this is the only candidate, there is no point
 202                  * calling the disambiguation hint callback.
 203                  *
 204                  * On the other hand, if the current candidate
 205                  * replaced an earlier candidate that did _not_ pass
 206                  * the disambiguation hint callback, then we do have
 207                  * more than one objects that match the short name
 208                  * given, so we should make sure this one matches;
 209                  * otherwise, if we discovered this one and the one
 210                  * that we previously discarded in the reverse order,
 211                  * we would end up showing different results in the
 212                  * same repository!
 213                  */
 214                 ds->candidate_ok = (!ds->disambiguate_fn_used ||
 215                                     ds->fn(&ds->candidate, ds->cb_data));
 216
 217         if (!ds->candidate_ok)
 218                 return SHORT_NAME_AMBIGUOUS;
 219
 220         oidcpy(oid, &ds->candidate);
 221         return 0;
 222 }
 223
 224 static int disambiguate_commit_only(const struct object_id *oid, void *cb_data_unused)
 225 {
 226         int kind = oid_object_info(the_repository, oid, NULL);
 227         return kind == OBJ_COMMIT;
 228 }
 229
 230 static int disambiguate_committish_only(const struct object_id *oid, void *cb_data_unused)
 231 {
 232         struct object *obj;
 233         int kind;
 234
 235         kind = oid_object_info(the_repository, oid, NULL);
 236         if (kind == OBJ_COMMIT)
 237                 return 1;
 238         if (kind != OBJ_TAG)
 239                 return 0;
 240
 241         /* We need to do this the hard way... */
 242         obj = deref_tag(the_repository, parse_object(the_repository, oid),
 243                         NULL, 0);
 244         if (obj && obj->type == OBJ_COMMIT)
 245                 return 1;
 246         return 0;
 247 }
 248
 249 static int disambiguate_tree_only(const struct object_id *oid, void *cb_data_unused)
 250 {
 251         int kind = oid_object_info(the_repository, oid, NULL);
 252         return kind == OBJ_TREE;
 253 }
 254
 255 static int disambiguate_treeish_only(const struct object_id *oid, void *cb_data_unused)
 256 {
 257         struct object *obj;
 258         int kind;
 259
 260         kind = oid_object_info(the_repository, oid, NULL);
 261         if (kind == OBJ_TREE || kind == OBJ_COMMIT)
 262                 return 1;
 263         if (kind != OBJ_TAG)
 264                 return 0;
 265
 266         /* We need to do this the hard way... */
 267         obj = deref_tag(the_repository, parse_object(the_repository, oid),
 268                         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 struct object_id *oid, void *cb_data_unused)
 275 {
 276         int kind = oid_object_info(the_repository, oid, NULL);
 277         return kind == OBJ_BLOB;
 278 }
 279
 280 static disambiguate_hint_fn default_disambiguate_hint;
 281
 282 int set_disambiguate_hint_config(const char *var, const char *value)
 283 {
 284         static const struct {
 285                 const char *name;
 286                 disambiguate_hint_fn fn;
 287         } hints[] = {
 288                 { "none", NULL },
 289                 { "commit", disambiguate_commit_only },
 290                 { "committish", disambiguate_committish_only },
 291                 { "tree", disambiguate_tree_only },
 292                 { "treeish", disambiguate_treeish_only },
 293                 { "blob", disambiguate_blob_only }
 294         };
 295         int i;
 296
 297         if (!value)
 298                 return config_error_nonbool(var);
 299
 300         for (i = 0; i < ARRAY_SIZE(hints); i++) {
 301                 if (!strcasecmp(value, hints[i].name)) {
 302                         default_disambiguate_hint = hints[i].fn;
 303                         return 0;
 304                 }
 305         }
 306
 307         return error("unknown hint type for '%s': %s", var, value);
 308 }
 309
 310 static int init_object_disambiguation(const char *name, int len,
 311                                       struct disambiguate_state *ds)
 312 {
 313         int i;
 314
 315         if (len < MINIMUM_ABBREV || len > the_hash_algo->hexsz)
 316                 return -1;
 317
 318         memset(ds, 0, sizeof(*ds));
 319
 320         for (i = 0; i < len ;i++) {
 321                 unsigned char c = name[i];
 322                 unsigned char val;
 323                 if (c >= '0' && c <= '9')
 324                         val = c - '0';
 325                 else if (c >= 'a' && c <= 'f')
 326                         val = c - 'a' + 10;
 327                 else if (c >= 'A' && c <='F') {
 328                         val = c - 'A' + 10;
 329                         c -= 'A' - 'a';
 330                 }
 331                 else
 332                         return -1;
 333                 ds->hex_pfx[i] = c;
 334                 if (!(i & 1))
 335                         val <<= 4;
 336                 ds->bin_pfx.hash[i >> 1] |= val;
 337         }
 338
 339         ds->len = len;
 340         ds->hex_pfx[len] = '\0';
 341         prepare_alt_odb(the_repository);
 342         return 0;
 343 }
 344
 345 static int show_ambiguous_object(const struct object_id *oid, void *data)
 346 {
 347         const struct disambiguate_state *ds = data;
 348         struct strbuf desc = STRBUF_INIT;
 349         int type;
 350
 351         if (ds->fn && !ds->fn(oid, ds->cb_data))
 352                 return 0;
 353
 354         type = oid_object_info(the_repository, oid, NULL);
 355         if (type == OBJ_COMMIT) {
 356                 struct commit *commit = lookup_commit(the_repository, oid);
 357                 if (commit) {
 358                         struct pretty_print_context pp = {0};
 359                         pp.date_mode.type = DATE_SHORT;
 360                         format_commit_message(commit, " %ad - %s", &desc, &pp);
 361                 }
 362         } else if (type == OBJ_TAG) {
 363                 struct tag *tag = lookup_tag(the_repository, oid);
 364                 if (!parse_tag(tag) && tag->tag)
 365                         strbuf_addf(&desc, " %s", tag->tag);
 366         }
 367
 368         advise("  %s %s%s",
 369                find_unique_abbrev(oid, DEFAULT_ABBREV),
 370                type_name(type) ? type_name(type) : "unknown type",
 371                desc.buf);
 372
 373         strbuf_release(&desc);
 374         return 0;
 375 }
 376
 377 static int collect_ambiguous(const struct object_id *oid, void *data)
 378 {
 379         oid_array_append(data, oid);
 380         return 0;
 381 }
 382
 383 static int sort_ambiguous(const void *a, const void *b)
 384 {
 385         int a_type = oid_object_info(the_repository, a, NULL);
 386         int b_type = oid_object_info(the_repository, b, NULL);
 387         int a_type_sort;
 388         int b_type_sort;
 389
 390         /*
 391          * Sorts by hash within the same object type, just as
 392          * oid_array_for_each_unique() would do.
 393          */
 394         if (a_type == b_type)
 395                 return oidcmp(a, b);
 396
 397         /*
 398          * Between object types show tags, then commits, and finally
 399          * trees and blobs.
 400          *
 401          * The object_type enum is commit, tree, blob, tag, but we
 402          * want tag, commit, tree blob. Cleverly (perhaps too
 403          * cleverly) do that with modulus, since the enum assigns 1 to
 404          * commit, so tag becomes 0.
 405          */
 406         a_type_sort = a_type % 4;
 407         b_type_sort = b_type % 4;
 408         return a_type_sort > b_type_sort ? 1 : -1;
 409 }
 410
 411 static int get_short_oid(const char *name, int len, struct object_id *oid,
 412                           unsigned flags)
 413 {
 414         int status;
 415         struct disambiguate_state ds;
 416         int quietly = !!(flags & GET_OID_QUIETLY);
 417
 418         if (init_object_disambiguation(name, len, &ds) < 0)
 419                 return -1;
 420
 421         if (HAS_MULTI_BITS(flags & GET_OID_DISAMBIGUATORS))
 422                 BUG("multiple get_short_oid disambiguator flags");
 423
 424         if (flags & GET_OID_COMMIT)
 425                 ds.fn = disambiguate_commit_only;
 426         else if (flags & GET_OID_COMMITTISH)
 427                 ds.fn = disambiguate_committish_only;
 428         else if (flags & GET_OID_TREE)
 429                 ds.fn = disambiguate_tree_only;
 430         else if (flags & GET_OID_TREEISH)
 431                 ds.fn = disambiguate_treeish_only;
 432         else if (flags & GET_OID_BLOB)
 433                 ds.fn = disambiguate_blob_only;
 434         else
 435                 ds.fn = default_disambiguate_hint;
 436
 437         find_short_object_filename(&ds);
 438         find_short_packed_object(&ds);
 439         status = finish_object_disambiguation(&ds, oid);
 440
 441         if (!quietly && (status == SHORT_NAME_AMBIGUOUS)) {
 442                 struct oid_array collect = OID_ARRAY_INIT;
 443
 444                 error(_("short SHA1 %s is ambiguous"), ds.hex_pfx);
 445
 446                 /*
 447                  * We may still have ambiguity if we simply saw a series of
 448                  * candidates that did not satisfy our hint function. In
 449                  * that case, we still want to show them, so disable the hint
 450                  * function entirely.
 451                  */
 452                 if (!ds.ambiguous)
 453                         ds.fn = NULL;
 454
 455                 advise(_("The candidates are:"));
 456                 for_each_abbrev(ds.hex_pfx, collect_ambiguous, &collect);
 457                 QSORT(collect.oid, collect.nr, sort_ambiguous);
 458
 459                 if (oid_array_for_each(&collect, show_ambiguous_object, &ds))
 460                         BUG("show_ambiguous_object shouldn't return non-zero");
 461                 oid_array_clear(&collect);
 462         }
 463
 464         return status;
 465 }
 466
 467 int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
 468 {
 469         struct oid_array collect = OID_ARRAY_INIT;
 470         struct disambiguate_state ds;
 471         int ret;
 472
 473         if (init_object_disambiguation(prefix, strlen(prefix), &ds) < 0)
 474                 return -1;
 475
 476         ds.always_call_fn = 1;
 477         ds.fn = collect_ambiguous;
 478         ds.cb_data = &collect;
 479         find_short_object_filename(&ds);
 480         find_short_packed_object(&ds);
 481
 482         ret = oid_array_for_each_unique(&collect, fn, cb_data);
 483         oid_array_clear(&collect);
 484         return ret;
 485 }
 486
 487 /*
 488  * Return the slot of the most-significant bit set in "val". There are various
 489  * ways to do this quickly with fls() or __builtin_clzl(), but speed is
 490  * probably not a big deal here.
 491  */
 492 static unsigned msb(unsigned long val)
 493 {
 494         unsigned r = 0;
 495         while (val >>= 1)
 496                 r++;
 497         return r;
 498 }
 499
 500 struct min_abbrev_data {
 501         unsigned int init_len;
 502         unsigned int cur_len;
 503         char *hex;
 504         const struct object_id *oid;
 505 };
 506
 507 static inline char get_hex_char_from_oid(const struct object_id *oid,
 508                                          unsigned int pos)
 509 {
 510         static const char hex[] = "0123456789abcdef";
 511
 512         if ((pos & 1) == 0)
 513                 return hex[oid->hash[pos >> 1] >> 4];
 514         else
 515                 return hex[oid->hash[pos >> 1] & 0xf];
 516 }
 517
 518 static int extend_abbrev_len(const struct object_id *oid, void *cb_data)
 519 {
 520         struct min_abbrev_data *mad = cb_data;
 521
 522         unsigned int i = mad->init_len;
 523         while (mad->hex[i] && mad->hex[i] == get_hex_char_from_oid(oid, i))
 524                 i++;
 525
 526         if (i < GIT_MAX_RAWSZ && i >= mad->cur_len)
 527                 mad->cur_len = i + 1;
 528
 529         return 0;
 530 }
 531
 532 static void find_abbrev_len_for_pack(struct packed_git *p,
 533                                      struct min_abbrev_data *mad)
 534 {
 535         int match = 0;
 536         uint32_t num, first = 0;
 537         struct object_id oid;
 538         const struct object_id *mad_oid;
 539
 540         if (open_pack_index(p) || !p->num_objects)
 541                 return;
 542
 543         num = p->num_objects;
 544         mad_oid = mad->oid;
 545         match = bsearch_pack(mad_oid, p, &first);
 546
 547         /*
 548          * first is now the position in the packfile where we would insert
 549          * mad->hash if it does not exist (or the position of mad->hash if
 550          * it does exist). Hence, we consider a maximum of two objects
 551          * nearby for the abbreviation length.
 552          */
 553         mad->init_len = 0;
 554         if (!match) {
 555                 if (nth_packed_object_oid(&oid, p, first))
 556                         extend_abbrev_len(&oid, mad);
 557         } else if (first < num - 1) {
 558                 if (nth_packed_object_oid(&oid, p, first + 1))
 559                         extend_abbrev_len(&oid, mad);
 560         }
 561         if (first > 0) {
 562                 if (nth_packed_object_oid(&oid, p, first - 1))
 563                         extend_abbrev_len(&oid, mad);
 564         }
 565         mad->init_len = mad->cur_len;
 566 }
 567
 568 static void find_abbrev_len_packed(struct min_abbrev_data *mad)
 569 {
 570         struct packed_git *p;
 571
 572         for (p = get_packed_git(the_repository); p; p = p->next)
 573                 find_abbrev_len_for_pack(p, mad);
 574 }
 575
 576 int find_unique_abbrev_r(char *hex, const struct object_id *oid, int len)
 577 {
 578         struct disambiguate_state ds;
 579         struct min_abbrev_data mad;
 580         struct object_id oid_ret;
 581         const unsigned hexsz = the_hash_algo->hexsz;
 582
 583         if (len < 0) {
 584                 unsigned long count = approximate_object_count();
 585                 /*
 586                  * Add one because the MSB only tells us the highest bit set,
 587                  * not including the value of all the _other_ bits (so "15"
 588                  * is only one off of 2^4, but the MSB is the 3rd bit.
 589                  */
 590                 len = msb(count) + 1;
 591                 /*
 592                  * We now know we have on the order of 2^len objects, which
 593                  * expects a collision at 2^(len/2). But we also care about hex
 594                  * chars, not bits, and there are 4 bits per hex. So all
 595                  * together we need to divide by 2 and round up.
 596                  */
 597                 len = DIV_ROUND_UP(len, 2);
 598                 /*
 599                  * For very small repos, we stick with our regular fallback.
 600                  */
 601                 if (len < FALLBACK_DEFAULT_ABBREV)
 602                         len = FALLBACK_DEFAULT_ABBREV;
 603         }
 604
 605         oid_to_hex_r(hex, oid);
 606         if (len == hexsz || !len)
 607                 return hexsz;
 608
 609         mad.init_len = len;
 610         mad.cur_len = len;
 611         mad.hex = hex;
 612         mad.oid = oid;
 613
 614         find_abbrev_len_packed(&mad);
 615
 616         if (init_object_disambiguation(hex, mad.cur_len, &ds) < 0)
 617                 return -1;
 618
 619         ds.fn = extend_abbrev_len;
 620         ds.always_call_fn = 1;
 621         ds.cb_data = (void *)&mad;
 622
 623         find_short_object_filename(&ds);
 624         (void)finish_object_disambiguation(&ds, &oid_ret);
 625
 626         hex[mad.cur_len] = 0;
 627         return mad.cur_len;
 628 }
 629
 630 const char *find_unique_abbrev(const struct object_id *oid, int len)
 631 {
 632         static int bufno;
 633         static char hexbuffer[4][GIT_MAX_HEXSZ + 1];
 634         char *hex = hexbuffer[bufno];
 635         bufno = (bufno + 1) % ARRAY_SIZE(hexbuffer);
 636         find_unique_abbrev_r(hex, oid, len);
 637         return hex;
 638 }
 639
 640 static int ambiguous_path(const char *path, int len)
 641 {
 642         int slash = 1;
 643         int cnt;
 644
 645         for (cnt = 0; cnt < len; cnt++) {
 646                 switch (*path++) {
 647                 case '\0':
 648                         break;
 649                 case '/':
 650                         if (slash)
 651                                 break;
 652                         slash = 1;
 653                         continue;
 654                 case '.':
 655                         continue;
 656                 default:
 657                         slash = 0;
 658                         continue;
 659                 }
 660                 break;
 661         }
 662         return slash;
 663 }
 664
 665 static inline int at_mark(const char *string, int len,
 666                           const char **suffix, int nr)
 667 {
 668         int i;
 669
 670         for (i = 0; i < nr; i++) {
 671                 int suffix_len = strlen(suffix[i]);
 672                 if (suffix_len <= len
 673                     && !strncasecmp(string, suffix[i], suffix_len))
 674                         return suffix_len;
 675         }
 676         return 0;
 677 }
 678
 679 static inline int upstream_mark(const char *string, int len)
 680 {
 681         const char *suffix[] = { "@{upstream}", "@{u}" };
 682         return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
 683 }
 684
 685 static inline int push_mark(const char *string, int len)
 686 {
 687         const char *suffix[] = { "@{push}" };
 688         return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
 689 }
 690
 691 static int get_oid_1(const char *name, int len, struct object_id *oid, unsigned lookup_flags);
 692 static int interpret_nth_prior_checkout(const char *name, int namelen, struct strbuf *buf);
 693
 694 static int get_oid_basic(const char *str, int len, struct object_id *oid,
 695                           unsigned int flags)
 696 {
 697         static const char *warn_msg = "refname '%.*s' is ambiguous.";
 698         static const char *object_name_msg = N_(
 699         "Git normally never creates a ref that ends with 40 hex characters\n"
 700         "because it will be ignored when you just specify 40-hex. These refs\n"
 701         "may be created by mistake. For example,\n"
 702         "\n"
 703         "  git checkout -b $br $(git rev-parse ...)\n"
 704         "\n"
 705         "where \"$br\" is somehow empty and a 40-hex ref is created. Please\n"
 706         "examine these refs and maybe delete them. Turn this message off by\n"
 707         "running \"git config advice.objectNameWarning false\"");
 708         struct object_id tmp_oid;
 709         char *real_ref = NULL;
 710         int refs_found = 0;
 711         int at, reflog_len, nth_prior = 0;
 712
 713         if (len == the_hash_algo->hexsz && !get_oid_hex(str, oid)) {
 714                 if (warn_ambiguous_refs && warn_on_object_refname_ambiguity) {
 715                         refs_found = dwim_ref(str, len, &tmp_oid, &real_ref);
 716                         if (refs_found > 0) {
 717                                 warning(warn_msg, len, str);
 718                                 if (advice_object_name_warning)
 719                                         fprintf(stderr, "%s\n", _(object_name_msg));
 720                         }
 721                         free(real_ref);
 722                 }
 723                 return 0;
 724         }
 725
 726         /* basic@{time or number or -number} format to query ref-log */
 727         reflog_len = at = 0;
 728         if (len && str[len-1] == '}') {
 729                 for (at = len-4; at >= 0; at--) {
 730                         if (str[at] == '@' && str[at+1] == '{') {
 731                                 if (str[at+2] == '-') {
 732                                         if (at != 0)
 733                                                 /* @{-N} not at start */
 734                                                 return -1;
 735                                         nth_prior = 1;
 736                                         continue;
 737                                 }
 738                                 if (!upstream_mark(str + at, len - at) &&
 739                                     !push_mark(str + at, len - at)) {
 740                                         reflog_len = (len-1) - (at+2);
 741                                         len = at;
 742                                 }
 743                                 break;
 744                         }
 745                 }
 746         }
 747
 748         /* Accept only unambiguous ref paths. */
 749         if (len && ambiguous_path(str, len))
 750                 return -1;
 751
 752         if (nth_prior) {
 753                 struct strbuf buf = STRBUF_INIT;
 754                 int detached;
 755
 756                 if (interpret_nth_prior_checkout(str, len, &buf) > 0) {
 757                         detached = (buf.len == the_hash_algo->hexsz && !get_oid_hex(buf.buf, oid));
 758                         strbuf_release(&buf);
 759                         if (detached)
 760                                 return 0;
 761                 }
 762         }
 763
 764         if (!len && reflog_len)
 765                 /* allow "@{...}" to mean the current branch reflog */
 766                 refs_found = dwim_ref("HEAD", 4, oid, &real_ref);
 767         else if (reflog_len)
 768                 refs_found = dwim_log(str, len, oid, &real_ref);
 769         else
 770                 refs_found = dwim_ref(str, len, oid, &real_ref);
 771
 772         if (!refs_found)
 773                 return -1;
 774
 775         if (warn_ambiguous_refs && !(flags & GET_OID_QUIETLY) &&
 776             (refs_found > 1 ||
 777              !get_short_oid(str, len, &tmp_oid, GET_OID_QUIETLY)))
 778                 warning(warn_msg, len, str);
 779
 780         if (reflog_len) {
 781                 int nth, i;
 782                 timestamp_t at_time;
 783                 timestamp_t co_time;
 784                 int co_tz, co_cnt;
 785
 786                 /* Is it asking for N-th entry, or approxidate? */
 787                 for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 788                         char ch = str[at+2+i];
 789                         if ('0' <= ch && ch <= '9')
 790                                 nth = nth * 10 + ch - '0';
 791                         else
 792                                 nth = -1;
 793                 }
 794                 if (100000000 <= nth) {
 795                         at_time = nth;
 796                         nth = -1;
 797                 } else if (0 <= nth)
 798                         at_time = 0;
 799                 else {
 800                         int errors = 0;
 801                         char *tmp = xstrndup(str + at + 2, reflog_len);
 802                         at_time = approxidate_careful(tmp, &errors);
 803                         free(tmp);
 804                         if (errors) {
 805                                 free(real_ref);
 806                                 return -1;
 807                         }
 808                 }
 809                 if (read_ref_at(real_ref, flags, at_time, nth, oid, NULL,
 810                                 &co_time, &co_tz, &co_cnt)) {
 811                         if (!len) {
 812                                 if (starts_with(real_ref, "refs/heads/")) {
 813                                         str = real_ref + 11;
 814                                         len = strlen(real_ref + 11);
 815                                 } else {
 816                                         /* detached HEAD */
 817                                         str = "HEAD";
 818                                         len = 4;
 819                                 }
 820                         }
 821                         if (at_time) {
 822                                 if (!(flags & GET_OID_QUIETLY)) {
 823                                         warning("Log for '%.*s' only goes "
 824                                                 "back to %s.", len, str,
 825                                                 show_date(co_time, co_tz, DATE_MODE(RFC2822)));
 826                                 }
 827                         } else {
 828                                 if (flags & GET_OID_QUIETLY) {
 829                                         exit(128);
 830                                 }
 831                                 die("Log for '%.*s' only has %d entries.",
 832                                     len, str, co_cnt);
 833                         }
 834                 }
 835         }
 836
 837         free(real_ref);
 838         return 0;
 839 }
 840
 841 static int get_parent(const char *name, int len,
 842                       struct object_id *result, int idx)
 843 {
 844         struct object_id oid;
 845         int ret = get_oid_1(name, len, &oid, GET_OID_COMMITTISH);
 846         struct commit *commit;
 847         struct commit_list *p;
 848
 849         if (ret)
 850                 return ret;
 851         commit = lookup_commit_reference(the_repository, &oid);
 852         if (parse_commit(commit))
 853                 return -1;
 854         if (!idx) {
 855                 oidcpy(result, &commit->object.oid);
 856                 return 0;
 857         }
 858         p = commit->parents;
 859         while (p) {
 860                 if (!--idx) {
 861                         oidcpy(result, &p->item->object.oid);
 862                         return 0;
 863                 }
 864                 p = p->next;
 865         }
 866         return -1;
 867 }
 868
 869 static int get_nth_ancestor(const char *name, int len,
 870                             struct object_id *result, int generation)
 871 {
 872         struct object_id oid;
 873         struct commit *commit;
 874         int ret;
 875
 876         ret = get_oid_1(name, len, &oid, GET_OID_COMMITTISH);
 877         if (ret)
 878                 return ret;
 879         commit = lookup_commit_reference(the_repository, &oid);
 880         if (!commit)
 881                 return -1;
 882
 883         while (generation--) {
 884                 if (parse_commit(commit) || !commit->parents)
 885                         return -1;
 886                 commit = commit->parents->item;
 887         }
 888         oidcpy(result, &commit->object.oid);
 889         return 0;
 890 }
 891
 892 struct object *peel_to_type(const char *name, int namelen,
 893                             struct object *o, enum object_type expected_type)
 894 {
 895         if (name && !namelen)
 896                 namelen = strlen(name);
 897         while (1) {
 898                 if (!o || (!o->parsed && !parse_object(the_repository, &o->oid)))
 899                         return NULL;
 900                 if (expected_type == OBJ_ANY || o->type == expected_type)
 901                         return o;
 902                 if (o->type == OBJ_TAG)
 903                         o = ((struct tag*) o)->tagged;
 904                 else if (o->type == OBJ_COMMIT)
 905                         o = &(get_commit_tree(((struct commit *)o))->object);
 906                 else {
 907                         if (name)
 908                                 error("%.*s: expected %s type, but the object "
 909                                       "dereferences to %s type",
 910                                       namelen, name, type_name(expected_type),
 911                                       type_name(o->type));
 912                         return NULL;
 913                 }
 914         }
 915 }
 916
 917 static int peel_onion(const char *name, int len, struct object_id *oid,
 918                       unsigned lookup_flags)
 919 {
 920         struct object_id outer;
 921         const char *sp;
 922         unsigned int expected_type = 0;
 923         struct object *o;
 924
 925         /*
 926          * "ref^{type}" dereferences ref repeatedly until you cannot
 927          * dereference anymore, or you get an object of given type,
 928          * whichever comes first.  "ref^{}" means just dereference
 929          * tags until you get a non-tag.  "ref^0" is a shorthand for
 930          * "ref^{commit}".  "commit^{tree}" could be used to find the
 931          * top-level tree of the given commit.
 932          */
 933         if (len < 4 || name[len-1] != '}')
 934                 return -1;
 935
 936         for (sp = name + len - 1; name <= sp; sp--) {
 937                 int ch = *sp;
 938                 if (ch == '{' && name < sp && sp[-1] == '^')
 939                         break;
 940         }
 941         if (sp <= name)
 942                 return -1;
 943
 944         sp++; /* beginning of type name, or closing brace for empty */
 945         if (starts_with(sp, "commit}"))
 946                 expected_type = OBJ_COMMIT;
 947         else if (starts_with(sp, "tag}"))
 948                 expected_type = OBJ_TAG;
 949         else if (starts_with(sp, "tree}"))
 950                 expected_type = OBJ_TREE;
 951         else if (starts_with(sp, "blob}"))
 952                 expected_type = OBJ_BLOB;
 953         else if (starts_with(sp, "object}"))
 954                 expected_type = OBJ_ANY;
 955         else if (sp[0] == '}')
 956                 expected_type = OBJ_NONE;
 957         else if (sp[0] == '/')
 958                 expected_type = OBJ_COMMIT;
 959         else
 960                 return -1;
 961
 962         lookup_flags &= ~GET_OID_DISAMBIGUATORS;
 963         if (expected_type == OBJ_COMMIT)
 964                 lookup_flags |= GET_OID_COMMITTISH;
 965         else if (expected_type == OBJ_TREE)
 966                 lookup_flags |= GET_OID_TREEISH;
 967
 968         if (get_oid_1(name, sp - name - 2, &outer, lookup_flags))
 969                 return -1;
 970
 971         o = parse_object(the_repository, &outer);
 972         if (!o)
 973                 return -1;
 974         if (!expected_type) {
 975                 o = deref_tag(the_repository, o, name, sp - name - 2);
 976                 if (!o || (!o->parsed && !parse_object(the_repository, &o->oid)))
 977                         return -1;
 978                 oidcpy(oid, &o->oid);
 979                 return 0;
 980         }
 981
 982         /*
 983          * At this point, the syntax look correct, so
 984          * if we do not get the needed object, we should
 985          * barf.
 986          */
 987         o = peel_to_type(name, len, o, expected_type);
 988         if (!o)
 989                 return -1;
 990
 991         oidcpy(oid, &o->oid);
 992         if (sp[0] == '/') {
 993                 /* "$commit^{/foo}" */
 994                 char *prefix;
 995                 int ret;
 996                 struct commit_list *list = NULL;
 997
 998                 /*
 999                  * $commit^{/}. Some regex implementation may reject.
1000                  * We don't need regex anyway. '' pattern always matches.
1001                  */
1002                 if (sp[1] == '}')
1003                         return 0;
1004
1005                 prefix = xstrndup(sp + 1, name + len - 1 - (sp + 1));
1006                 commit_list_insert((struct commit *)o, &list);
1007                 ret = get_oid_oneline(prefix, oid, list);
1008                 free(prefix);
1009                 return ret;
1010         }
1011         return 0;
1012 }
1013
1014 static int get_describe_name(const char *name, int len, struct object_id *oid)
1015 {
1016         const char *cp;
1017         unsigned flags = GET_OID_QUIETLY | GET_OID_COMMIT;
1018
1019         for (cp = name + len - 1; name + 2 <= cp; cp--) {
1020                 char ch = *cp;
1021                 if (!isxdigit(ch)) {
1022                         /* We must be looking at g in "SOMETHING-g"
1023                          * for it to be describe output.
1024                          */
1025                         if (ch == 'g' && cp[-1] == '-') {
1026                                 cp++;
1027                                 len -= cp - name;
1028                                 return get_short_oid(cp, len, oid, flags);
1029                         }
1030                 }
1031         }
1032         return -1;
1033 }
1034
1035 static int get_oid_1(const char *name, int len, struct object_id *oid, unsigned lookup_flags)
1036 {
1037         int ret, has_suffix;
1038         const char *cp;
1039
1040         /*
1041          * "name~3" is "name^^^", "name~" is "name~1", and "name^" is "name^1".
1042          */
1043         has_suffix = 0;
1044         for (cp = name + len - 1; name <= cp; cp--) {
1045                 int ch = *cp;
1046                 if ('0' <= ch && ch <= '9')
1047                         continue;
1048                 if (ch == '~' || ch == '^')
1049                         has_suffix = ch;
1050                 break;
1051         }
1052
1053         if (has_suffix) {
1054                 int num = 0;
1055                 int len1 = cp - name;
1056                 cp++;
1057                 while (cp < name + len)
1058                         num = num * 10 + *cp++ - '0';
1059                 if (!num && len1 == len - 1)
1060                         num = 1;
1061                 if (has_suffix == '^')
1062                         return get_parent(name, len1, oid, num);
1063                 /* else if (has_suffix == '~') -- goes without saying */
1064                 return get_nth_ancestor(name, len1, oid, num);
1065         }
1066
1067         ret = peel_onion(name, len, oid, lookup_flags);
1068         if (!ret)
1069                 return 0;
1070
1071         ret = get_oid_basic(name, len, oid, lookup_flags);
1072         if (!ret)
1073                 return 0;
1074
1075         /* It could be describe output that is "SOMETHING-gXXXX" */
1076         ret = get_describe_name(name, len, oid);
1077         if (!ret)
1078                 return 0;
1079
1080         return get_short_oid(name, len, oid, lookup_flags);
1081 }
1082
1083 /*
1084  * This interprets names like ':/Initial revision of "git"' by searching
1085  * through history and returning the first commit whose message starts
1086  * the given regular expression.
1087  *
1088  * For negative-matching, prefix the pattern-part with '!-', like: ':/!-WIP'.
1089  *
1090  * For a literal '!' character at the beginning of a pattern, you have to repeat
1091  * that, like: ':/!!foo'
1092  *
1093  * For future extension, all other sequences beginning with ':/!' are reserved.
1094  */
1095
1096 /* Remember to update object flag allocation in object.h */
1097 #define ONELINE_SEEN (1u<<20)
1098
1099 static int handle_one_ref(const char *path, const struct object_id *oid,
1100                           int flag, void *cb_data)
1101 {
1102         struct commit_list **list = cb_data;
1103         struct object *object = parse_object(the_repository, oid);
1104         if (!object)
1105                 return 0;
1106         if (object->type == OBJ_TAG) {
1107                 object = deref_tag(the_repository, object, path,
1108                                    strlen(path));
1109                 if (!object)
1110                         return 0;
1111         }
1112         if (object->type != OBJ_COMMIT)
1113                 return 0;
1114         commit_list_insert((struct commit *)object, list);
1115         return 0;
1116 }
1117
1118 static int get_oid_oneline(const char *prefix, struct object_id *oid,
1119                             struct commit_list *list)
1120 {
1121         struct commit_list *backup = NULL, *l;
1122         int found = 0;
1123         int negative = 0;
1124         regex_t regex;
1125
1126         if (prefix[0] == '!') {
1127                 prefix++;
1128
1129                 if (prefix[0] == '-') {
1130                         prefix++;
1131                         negative = 1;
1132                 } else if (prefix[0] != '!') {
1133                         return -1;
1134                 }
1135         }
1136
1137         if (regcomp(&regex, prefix, REG_EXTENDED))
1138                 return -1;
1139
1140         for (l = list; l; l = l->next) {
1141                 l->item->object.flags |= ONELINE_SEEN;
1142                 commit_list_insert(l->item, &backup);
1143         }
1144         while (list) {
1145                 const char *p, *buf;
1146                 struct commit *commit;
1147                 int matches;
1148
1149                 commit = pop_most_recent_commit(&list, ONELINE_SEEN);
1150                 if (!parse_object(the_repository, &commit->object.oid))
1151                         continue;
1152                 buf = get_commit_buffer(commit, NULL);
1153                 p = strstr(buf, "\n\n");
1154                 matches = negative ^ (p && !regexec(&regex, p + 2, 0, NULL, 0));
1155                 unuse_commit_buffer(commit, buf);
1156
1157                 if (matches) {
1158                         oidcpy(oid, &commit->object.oid);
1159                         found = 1;
1160                         break;
1161                 }
1162         }
1163         regfree(&regex);
1164         free_commit_list(list);
1165         for (l = backup; l; l = l->next)
1166                 clear_commit_marks(l->item, ONELINE_SEEN);
1167         free_commit_list(backup);
1168         return found ? 0 : -1;
1169 }
1170
1171 struct grab_nth_branch_switch_cbdata {
1172         int remaining;
1173         struct strbuf buf;
1174 };
1175
1176 static int grab_nth_branch_switch(struct object_id *ooid, struct object_id *noid,
1177                                   const char *email, timestamp_t timestamp, int tz,
1178                                   const char *message, void *cb_data)
1179 {
1180         struct grab_nth_branch_switch_cbdata *cb = cb_data;
1181         const char *match = NULL, *target = NULL;
1182         size_t len;
1183
1184         if (skip_prefix(message, "checkout: moving from ", &match))
1185                 target = strstr(match, " to ");
1186
1187         if (!match || !target)
1188                 return 0;
1189         if (--(cb->remaining) == 0) {
1190                 len = target - match;
1191                 strbuf_reset(&cb->buf);
1192                 strbuf_add(&cb->buf, match, len);
1193                 return 1; /* we are done */
1194         }
1195         return 0;
1196 }
1197
1198 /*
1199  * Parse @{-N} syntax, return the number of characters parsed
1200  * if successful; otherwise signal an error with negative value.
1201  */
1202 static int interpret_nth_prior_checkout(const char *name, int namelen,
1203                                         struct strbuf *buf)
1204 {
1205         long nth;
1206         int retval;
1207         struct grab_nth_branch_switch_cbdata cb;
1208         const char *brace;
1209         char *num_end;
1210
1211         if (namelen < 4)
1212                 return -1;
1213         if (name[0] != '@' || name[1] != '{' || name[2] != '-')
1214                 return -1;
1215         brace = memchr(name, '}', namelen);
1216         if (!brace)
1217                 return -1;
1218         nth = strtol(name + 3, &num_end, 10);
1219         if (num_end != brace)
1220                 return -1;
1221         if (nth <= 0)
1222                 return -1;
1223         cb.remaining = nth;
1224         strbuf_init(&cb.buf, 20);
1225
1226         retval = 0;
1227         if (0 < for_each_reflog_ent_reverse("HEAD", grab_nth_branch_switch, &cb)) {
1228                 strbuf_reset(buf);
1229                 strbuf_addbuf(buf, &cb.buf);
1230                 retval = brace - name + 1;
1231         }
1232
1233         strbuf_release(&cb.buf);
1234         return retval;
1235 }
1236
1237 int get_oid_mb(const char *name, struct object_id *oid)
1238 {
1239         struct commit *one, *two;
1240         struct commit_list *mbs;
1241         struct object_id oid_tmp;
1242         const char *dots;
1243         int st;
1244
1245         dots = strstr(name, "...");
1246         if (!dots)
1247                 return get_oid(name, oid);
1248         if (dots == name)
1249                 st = get_oid("HEAD", &oid_tmp);
1250         else {
1251                 struct strbuf sb;
1252                 strbuf_init(&sb, dots - name);
1253                 strbuf_add(&sb, name, dots - name);
1254                 st = get_oid_committish(sb.buf, &oid_tmp);
1255                 strbuf_release(&sb);
1256         }
1257         if (st)
1258                 return st;
1259         one = lookup_commit_reference_gently(the_repository, &oid_tmp, 0);
1260         if (!one)
1261                 return -1;
1262
1263         if (get_oid_committish(dots[3] ? (dots + 3) : "HEAD", &oid_tmp))
1264                 return -1;
1265         two = lookup_commit_reference_gently(the_repository, &oid_tmp, 0);
1266         if (!two)
1267                 return -1;
1268         mbs = get_merge_bases(one, two);
1269         if (!mbs || mbs->next)
1270                 st = -1;
1271         else {
1272                 st = 0;
1273                 oidcpy(oid, &mbs->item->object.oid);
1274         }
1275         free_commit_list(mbs);
1276         return st;
1277 }
1278
1279 /* parse @something syntax, when 'something' is not {.*} */
1280 static int interpret_empty_at(const char *name, int namelen, int len, struct strbuf *buf)
1281 {
1282         const char *next;
1283
1284         if (len || name[1] == '{')
1285                 return -1;
1286
1287         /* make sure it's a single @, or @@{.*}, not @foo */
1288         next = memchr(name + len + 1, '@', namelen - len - 1);
1289         if (next && next[1] != '{')
1290                 return -1;
1291         if (!next)
1292                 next = name + namelen;
1293         if (next != name + 1)
1294                 return -1;
1295
1296         strbuf_reset(buf);
1297         strbuf_add(buf, "HEAD", 4);
1298         return 1;
1299 }
1300
1301 static int reinterpret(const char *name, int namelen, int len,
1302                        struct strbuf *buf, unsigned allowed)
1303 {
1304         /* we have extra data, which might need further processing */
1305         struct strbuf tmp = STRBUF_INIT;
1306         int used = buf->len;
1307         int ret;
1308
1309         strbuf_add(buf, name + len, namelen - len);
1310         ret = interpret_branch_name(buf->buf, buf->len, &tmp, allowed);
1311         /* that data was not interpreted, remove our cruft */
1312         if (ret < 0) {
1313                 strbuf_setlen(buf, used);
1314                 return len;
1315         }
1316         strbuf_reset(buf);
1317         strbuf_addbuf(buf, &tmp);
1318         strbuf_release(&tmp);
1319         /* tweak for size of {-N} versus expanded ref name */
1320         return ret - used + len;
1321 }
1322
1323 static void set_shortened_ref(struct strbuf *buf, const char *ref)
1324 {
1325         char *s = shorten_unambiguous_ref(ref, 0);
1326         strbuf_reset(buf);
1327         strbuf_addstr(buf, s);
1328         free(s);
1329 }
1330
1331 static int branch_interpret_allowed(const char *refname, unsigned allowed)
1332 {
1333         if (!allowed)
1334                 return 1;
1335
1336         if ((allowed & INTERPRET_BRANCH_LOCAL) &&
1337             starts_with(refname, "refs/heads/"))
1338                 return 1;
1339         if ((allowed & INTERPRET_BRANCH_REMOTE) &&
1340             starts_with(refname, "refs/remotes/"))
1341                 return 1;
1342
1343         return 0;
1344 }
1345
1346 static int interpret_branch_mark(const char *name, int namelen,
1347                                  int at, struct strbuf *buf,
1348                                  int (*get_mark)(const char *, int),
1349                                  const char *(*get_data)(struct branch *,
1350                                                          struct strbuf *),
1351                                  unsigned allowed)
1352 {
1353         int len;
1354         struct branch *branch;
1355         struct strbuf err = STRBUF_INIT;
1356         const char *value;
1357
1358         len = get_mark(name + at, namelen - at);
1359         if (!len)
1360                 return -1;
1361
1362         if (memchr(name, ':', at))
1363                 return -1;
1364
1365         if (at) {
1366                 char *name_str = xmemdupz(name, at);
1367                 branch = branch_get(name_str);
1368                 free(name_str);
1369         } else
1370                 branch = branch_get(NULL);
1371
1372         value = get_data(branch, &err);
1373         if (!value)
1374                 die("%s", err.buf);
1375
1376         if (!branch_interpret_allowed(value, allowed))
1377                 return -1;
1378
1379         set_shortened_ref(buf, value);
1380         return len + at;
1381 }
1382
1383 int interpret_branch_name(const char *name, int namelen, struct strbuf *buf,
1384                           unsigned allowed)
1385 {
1386         char *at;
1387         const char *start;
1388         int len;
1389
1390         if (!namelen)
1391                 namelen = strlen(name);
1392
1393         if (!allowed || (allowed & INTERPRET_BRANCH_LOCAL)) {
1394                 len = interpret_nth_prior_checkout(name, namelen, buf);
1395                 if (!len) {
1396                         return len; /* syntax Ok, not enough switches */
1397                 } else if (len > 0) {
1398                         if (len == namelen)
1399                                 return len; /* consumed all */
1400                         else
1401                                 return reinterpret(name, namelen, len, buf, allowed);
1402                 }
1403         }
1404
1405         for (start = name;
1406              (at = memchr(start, '@', namelen - (start - name)));
1407              start = at + 1) {
1408
1409                 if (!allowed || (allowed & INTERPRET_BRANCH_HEAD)) {
1410                         len = interpret_empty_at(name, namelen, at - name, buf);
1411                         if (len > 0)
1412                                 return reinterpret(name, namelen, len, buf,
1413                                                    allowed);
1414                 }
1415
1416                 len = interpret_branch_mark(name, namelen, at - name, buf,
1417                                             upstream_mark, branch_get_upstream,
1418                                             allowed);
1419                 if (len > 0)
1420                         return len;
1421
1422                 len = interpret_branch_mark(name, namelen, at - name, buf,
1423                                             push_mark, branch_get_push,
1424                                             allowed);
1425                 if (len > 0)
1426                         return len;
1427         }
1428
1429         return -1;
1430 }
1431
1432 void strbuf_branchname(struct strbuf *sb, const char *name, unsigned allowed)
1433 {
1434         int len = strlen(name);
1435         int used = interpret_branch_name(name, len, sb, allowed);
1436
1437         if (used < 0)
1438                 used = 0;
1439         strbuf_add(sb, name + used, len - used);
1440 }
1441
1442 int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
1443 {
1444         if (startup_info->have_repository)
1445                 strbuf_branchname(sb, name, INTERPRET_BRANCH_LOCAL);
1446         else
1447                 strbuf_addstr(sb, name);
1448
1449         /*
1450          * This splice must be done even if we end up rejecting the
1451          * name; builtin/branch.c::copy_or_rename_branch() still wants
1452          * to see what the name expanded to so that "branch -m" can be
1453          * used as a tool to correct earlier mistakes.
1454          */
1455         strbuf_splice(sb, 0, 0, "refs/heads/", 11);
1456
1457         if (*name == '-' ||
1458             !strcmp(sb->buf, "refs/heads/HEAD"))
1459                 return -1;
1460
1461         return check_refname_format(sb->buf, 0);
1462 }
1463
1464 /*
1465  * This is like "get_oid_basic()", except it allows "object ID expressions",
1466  * notably "xyz^" for "parent of xyz"
1467  */
1468 int get_oid(const char *name, struct object_id *oid)
1469 {
1470         struct object_context unused;
1471         return get_oid_with_context(name, 0, oid, &unused);
1472 }
1473
1474
1475 /*
1476  * Many callers know that the user meant to name a commit-ish by
1477  * syntactical positions where the object name appears.  Calling this
1478  * function allows the machinery to disambiguate shorter-than-unique
1479  * abbreviated object names between commit-ish and others.
1480  *
1481  * Note that this does NOT error out when the named object is not a
1482  * commit-ish. It is merely to give a hint to the disambiguation
1483  * machinery.
1484  */
1485 int get_oid_committish(const char *name, struct object_id *oid)
1486 {
1487         struct object_context unused;
1488         return get_oid_with_context(name, GET_OID_COMMITTISH,
1489                                     oid, &unused);
1490 }
1491
1492 int get_oid_treeish(const char *name, struct object_id *oid)
1493 {
1494         struct object_context unused;
1495         return get_oid_with_context(name, GET_OID_TREEISH,
1496                                     oid, &unused);
1497 }
1498
1499 int get_oid_commit(const char *name, struct object_id *oid)
1500 {
1501         struct object_context unused;
1502         return get_oid_with_context(name, GET_OID_COMMIT,
1503                                     oid, &unused);
1504 }
1505
1506 int get_oid_tree(const char *name, struct object_id *oid)
1507 {
1508         struct object_context unused;
1509         return get_oid_with_context(name, GET_OID_TREE,
1510                                     oid, &unused);
1511 }
1512
1513 int get_oid_blob(const char *name, struct object_id *oid)
1514 {
1515         struct object_context unused;
1516         return get_oid_with_context(name, GET_OID_BLOB,
1517                                     oid, &unused);
1518 }
1519
1520 /* Must be called only when object_name:filename doesn't exist. */
1521 static void diagnose_invalid_oid_path(const char *prefix,
1522                                       const char *filename,
1523                                       const struct object_id *tree_oid,
1524                                       const char *object_name,
1525                                       int object_name_len)
1526 {
1527         struct object_id oid;
1528         unsigned mode;
1529
1530         if (!prefix)
1531                 prefix = "";
1532
1533         if (file_exists(filename))
1534                 die("Path '%s' exists on disk, but not in '%.*s'.",
1535                     filename, object_name_len, object_name);
1536         if (is_missing_file_error(errno)) {
1537                 char *fullname = xstrfmt("%s%s", prefix, filename);
1538
1539                 if (!get_tree_entry(tree_oid, fullname, &oid, &mode)) {
1540                         die("Path '%s' exists, but not '%s'.\n"
1541                             "Did you mean '%.*s:%s' aka '%.*s:./%s'?",
1542                             fullname,
1543                             filename,
1544                             object_name_len, object_name,
1545                             fullname,
1546                             object_name_len, object_name,
1547                             filename);
1548                 }
1549                 die("Path '%s' does not exist in '%.*s'",
1550                     filename, object_name_len, object_name);
1551         }
1552 }
1553
1554 /* Must be called only when :stage:filename doesn't exist. */
1555 static void diagnose_invalid_index_path(int stage,
1556                                         const char *prefix,
1557                                         const char *filename)
1558 {
1559         const struct cache_entry *ce;
1560         int pos;
1561         unsigned namelen = strlen(filename);
1562         struct strbuf fullname = STRBUF_INIT;
1563
1564         if (!prefix)
1565                 prefix = "";
1566
1567         /* Wrong stage number? */
1568         pos = cache_name_pos(filename, namelen);
1569         if (pos < 0)
1570                 pos = -pos - 1;
1571         if (pos < active_nr) {
1572                 ce = active_cache[pos];
1573                 if (ce_namelen(ce) == namelen &&
1574                     !memcmp(ce->name, filename, namelen))
1575                         die("Path '%s' is in the index, but not at stage %d.\n"
1576                             "Did you mean ':%d:%s'?",
1577                             filename, stage,
1578                             ce_stage(ce), filename);
1579         }
1580
1581         /* Confusion between relative and absolute filenames? */
1582         strbuf_addstr(&fullname, prefix);
1583         strbuf_addstr(&fullname, filename);
1584         pos = cache_name_pos(fullname.buf, fullname.len);
1585         if (pos < 0)
1586                 pos = -pos - 1;
1587         if (pos < active_nr) {
1588                 ce = active_cache[pos];
1589                 if (ce_namelen(ce) == fullname.len &&
1590                     !memcmp(ce->name, fullname.buf, fullname.len))
1591                         die("Path '%s' is in the index, but not '%s'.\n"
1592                             "Did you mean ':%d:%s' aka ':%d:./%s'?",
1593                             fullname.buf, filename,
1594                             ce_stage(ce), fullname.buf,
1595                             ce_stage(ce), filename);
1596         }
1597
1598         if (file_exists(filename))
1599                 die("Path '%s' exists on disk, but not in the index.", filename);
1600         if (is_missing_file_error(errno))
1601                 die("Path '%s' does not exist (neither on disk nor in the index).",
1602                     filename);
1603
1604         strbuf_release(&fullname);
1605 }
1606
1607
1608 static char *resolve_relative_path(const char *rel)
1609 {
1610         if (!starts_with(rel, "./") && !starts_with(rel, "../"))
1611                 return NULL;
1612
1613         if (!is_inside_work_tree())
1614                 die("relative path syntax can't be used outside working tree.");
1615
1616         /* die() inside prefix_path() if resolved path is outside worktree */
1617         return prefix_path(startup_info->prefix,
1618                            startup_info->prefix ? strlen(startup_info->prefix) : 0,
1619                            rel);
1620 }
1621
1622 static int get_oid_with_context_1(const char *name,
1623                                   unsigned flags,
1624                                   const char *prefix,
1625                                   struct object_id *oid,
1626                                   struct object_context *oc)
1627 {
1628         int ret, bracket_depth;
1629         int namelen = strlen(name);
1630         const char *cp;
1631         int only_to_die = flags & GET_OID_ONLY_TO_DIE;
1632
1633         if (only_to_die)
1634                 flags |= GET_OID_QUIETLY;
1635
1636         memset(oc, 0, sizeof(*oc));
1637         oc->mode = S_IFINVALID;
1638         strbuf_init(&oc->symlink_path, 0);
1639         ret = get_oid_1(name, namelen, oid, flags);
1640         if (!ret)
1641                 return ret;
1642         /*
1643          * sha1:path --> object name of path in ent sha1
1644          * :path -> object name of absolute path in index
1645          * :./path -> object name of path relative to cwd in index
1646          * :[0-3]:path -> object name of path in index at stage
1647          * :/foo -> recent commit matching foo
1648          */
1649         if (name[0] == ':') {
1650                 int stage = 0;
1651                 const struct cache_entry *ce;
1652                 char *new_path = NULL;
1653                 int pos;
1654                 if (!only_to_die && namelen > 2 && name[1] == '/') {
1655                         struct commit_list *list = NULL;
1656
1657                         for_each_ref(handle_one_ref, &list);
1658                         head_ref(handle_one_ref, &list);
1659                         commit_list_sort_by_date(&list);
1660                         return get_oid_oneline(name + 2, oid, list);
1661                 }
1662                 if (namelen < 3 ||
1663                     name[2] != ':' ||
1664                     name[1] < '0' || '3' < name[1])
1665                         cp = name + 1;
1666                 else {
1667                         stage = name[1] - '0';
1668                         cp = name + 3;
1669                 }
1670                 new_path = resolve_relative_path(cp);
1671                 if (!new_path) {
1672                         namelen = namelen - (cp - name);
1673                 } else {
1674                         cp = new_path;
1675                         namelen = strlen(cp);
1676                 }
1677
1678                 if (flags & GET_OID_RECORD_PATH)
1679                         oc->path = xstrdup(cp);
1680
1681                 if (!active_cache)
1682                         read_cache();
1683                 pos = cache_name_pos(cp, namelen);
1684                 if (pos < 0)
1685                         pos = -pos - 1;
1686                 while (pos < active_nr) {
1687                         ce = active_cache[pos];
1688                         if (ce_namelen(ce) != namelen ||
1689                             memcmp(ce->name, cp, namelen))
1690                                 break;
1691                         if (ce_stage(ce) == stage) {
1692                                 oidcpy(oid, &ce->oid);
1693                                 oc->mode = ce->ce_mode;
1694                                 free(new_path);
1695                                 return 0;
1696                         }
1697                         pos++;
1698                 }
1699                 if (only_to_die && name[1] && name[1] != '/')
1700                         diagnose_invalid_index_path(stage, prefix, cp);
1701                 free(new_path);
1702                 return -1;
1703         }
1704         for (cp = name, bracket_depth = 0; *cp; cp++) {
1705                 if (*cp == '{')
1706                         bracket_depth++;
1707                 else if (bracket_depth && *cp == '}')
1708                         bracket_depth--;
1709                 else if (!bracket_depth && *cp == ':')
1710                         break;
1711         }
1712         if (*cp == ':') {
1713                 struct object_id tree_oid;
1714                 int len = cp - name;
1715                 unsigned sub_flags = flags;
1716
1717                 sub_flags &= ~GET_OID_DISAMBIGUATORS;
1718                 sub_flags |= GET_OID_TREEISH;
1719
1720                 if (!get_oid_1(name, len, &tree_oid, sub_flags)) {
1721                         const char *filename = cp+1;
1722                         char *new_filename = NULL;
1723
1724                         new_filename = resolve_relative_path(filename);
1725                         if (new_filename)
1726                                 filename = new_filename;
1727                         if (flags & GET_OID_FOLLOW_SYMLINKS) {
1728                                 ret = get_tree_entry_follow_symlinks(&tree_oid,
1729                                         filename, oid, &oc->symlink_path,
1730                                         &oc->mode);
1731                         } else {
1732                                 ret = get_tree_entry(&tree_oid, filename, oid,
1733                                                      &oc->mode);
1734                                 if (ret && only_to_die) {
1735                                         diagnose_invalid_oid_path(prefix,
1736                                                                    filename,
1737                                                                    &tree_oid,
1738                                                                    name, len);
1739                                 }
1740                         }
1741                         if (flags & GET_OID_RECORD_PATH)
1742                                 oc->path = xstrdup(filename);
1743
1744                         free(new_filename);
1745                         return ret;
1746                 } else {
1747                         if (only_to_die)
1748                                 die("Invalid object name '%.*s'.", len, name);
1749                 }
1750         }
1751         return ret;
1752 }
1753
1754 /*
1755  * Call this function when you know "name" given by the end user must
1756  * name an object but it doesn't; the function _may_ die with a better
1757  * diagnostic message than "no such object 'name'", e.g. "Path 'doc' does not
1758  * exist in 'HEAD'" when given "HEAD:doc", or it may return in which case
1759  * you have a chance to diagnose the error further.
1760  */
1761 void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
1762 {
1763         struct object_context oc;
1764         struct object_id oid;
1765         get_oid_with_context_1(name, GET_OID_ONLY_TO_DIE, prefix, &oid, &oc);
1766 }
1767
1768 int get_oid_with_context(const char *str, unsigned flags, struct object_id *oid, struct object_context *oc)
1769 {
1770         if (flags & GET_OID_FOLLOW_SYMLINKS && flags & GET_OID_ONLY_TO_DIE)
1771                 BUG("incompatible flags for get_sha1_with_context");
1772         return get_oid_with_context_1(str, flags, NULL, oid, oc);
1773 }