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 #include "midx.h"
  16
  17 static int get_oid_oneline(const char *, struct object_id *, struct commit_list *);
  18
  19 typedef int (*disambiguate_hint_fn)(const struct object_id *, void *);
  20
  21 struct disambiguate_state {
  22         int len; /* length of prefix in hex chars */
  23         char hex_pfx[GIT_MAX_HEXSZ + 1];
  24         struct object_id bin_pfx;
  25
  26         disambiguate_hint_fn fn;
  27         void *cb_data;
  28         struct object_id candidate;
  29         unsigned candidate_exists:1;
  30         unsigned candidate_checked:1;
  31         unsigned candidate_ok:1;
  32         unsigned disambiguate_fn_used:1;
  33         unsigned ambiguous:1;
  34         unsigned always_call_fn:1;
  35 };
  36
  37 static void update_candidates(struct disambiguate_state *ds, const struct object_id *current)
  38 {
  39         if (ds->always_call_fn) {
  40                 ds->ambiguous = ds->fn(current, ds->cb_data) ? 1 : 0;
  41                 return;
  42         }
  43         if (!ds->candidate_exists) {
  44                 /* this is the first candidate */
  45                 oidcpy(&ds->candidate, current);
  46                 ds->candidate_exists = 1;
  47                 return;
  48         } else if (!oidcmp(&ds->candidate, current)) {
  49                 /* the same as what we already have seen */
  50                 return;
  51         }
  52
  53         if (!ds->fn) {
  54                 /* cannot disambiguate between ds->candidate and current */
  55                 ds->ambiguous = 1;
  56                 return;
  57         }
  58
  59         if (!ds->candidate_checked) {
  60                 ds->candidate_ok = ds->fn(&ds->candidate, ds->cb_data);
  61                 ds->disambiguate_fn_used = 1;
  62                 ds->candidate_checked = 1;
  63         }
  64
  65         if (!ds->candidate_ok) {
  66                 /* discard the candidate; we know it does not satisfy fn */
  67                 oidcpy(&ds->candidate, current);
  68                 ds->candidate_checked = 0;
  69                 return;
  70         }
  71
  72         /* if we reach this point, we know ds->candidate satisfies fn */
  73         if (ds->fn(current, ds->cb_data)) {
  74                 /*
  75                  * if both current and candidate satisfy fn, we cannot
  76                  * disambiguate.
  77                  */
  78                 ds->candidate_ok = 0;
  79                 ds->ambiguous = 1;
  80         }
  81
  82         /* otherwise, current can be discarded and candidate is still good */
  83 }
  84
  85 static int append_loose_object(const struct object_id *oid, const char *path,
  86                                void *data)
  87 {
  88         oid_array_append(data, oid);
  89         return 0;
  90 }
  91
  92 static int match_sha(unsigned, const unsigned char *, const unsigned char *);
  93
  94 static void find_short_object_filename(struct disambiguate_state *ds)
  95 {
  96         int subdir_nr = ds->bin_pfx.hash[0];
  97         struct alternate_object_database *alt;
  98         static struct alternate_object_database *fakeent;
  99
 100         if (!fakeent) {
 101                 /*
 102                  * Create a "fake" alternate object database that
 103                  * points to our own object database, to make it
 104                  * easier to get a temporary working space in
 105                  * alt->name/alt->base while iterating over the
 106                  * object databases including our own.
 107                  */
 108                 fakeent = alloc_alt_odb(get_object_directory());
 109         }
 110         fakeent->next = the_repository->objects->alt_odb_list;
 111
 112         for (alt = fakeent; alt && !ds->ambiguous; alt = alt->next) {
 113                 int pos;
 114
 115                 if (!alt->loose_objects_subdir_seen[subdir_nr]) {
 116                         struct strbuf *buf = alt_scratch_buf(alt);
 117                         for_each_file_in_obj_subdir(subdir_nr, buf,
 118                                                     append_loose_object,
 119                                                     NULL, NULL,
 120                                                     &alt->loose_objects_cache);
 121                         alt->loose_objects_subdir_seen[subdir_nr] = 1;
 122                 }
 123
 124                 pos = oid_array_lookup(&alt->loose_objects_cache, &ds->bin_pfx);
 125                 if (pos < 0)
 126                         pos = -1 - pos;
 127                 while (!ds->ambiguous && pos < alt->loose_objects_cache.nr) {
 128                         const struct object_id *oid;
 129                         oid = alt->loose_objects_cache.oid + pos;
 130                         if (!match_sha(ds->len, ds->bin_pfx.hash, oid->hash))
 131                                 break;
 132                         update_candidates(ds, oid);
 133                         pos++;
 134                 }
 135         }
 136 }
 137
 138 static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
 139 {
 140         do {
 141                 if (*a != *b)
 142                         return 0;
 143                 a++;
 144                 b++;
 145                 len -= 2;
 146         } while (len > 1);
 147         if (len)
 148                 if ((*a ^ *b) & 0xf0)
 149                         return 0;
 150         return 1;
 151 }
 152
 153 static void unique_in_midx(struct multi_pack_index *m,
 154                            struct disambiguate_state *ds)
 155 {
 156         uint32_t num, i, first = 0;
 157         const struct object_id *current = NULL;
 158         num = m->num_objects;
 159
 160         if (!num)
 161                 return;
 162
 163         bsearch_midx(&ds->bin_pfx, m, &first);
 164
 165         /*
 166          * At this point, "first" is the location of the lowest object
 167          * with an object name that could match "bin_pfx".  See if we have
 168          * 0, 1 or more objects that actually match(es).
 169          */
 170         for (i = first; i < num && !ds->ambiguous; i++) {
 171                 struct object_id oid;
 172                 current = nth_midxed_object_oid(&oid, m, i);
 173                 if (!match_sha(ds->len, ds->bin_pfx.hash, current->hash))
 174                         break;
 175                 update_candidates(ds, current);
 176         }
 177 }
 178
 179 static void unique_in_pack(struct packed_git *p,
 180                            struct disambiguate_state *ds)
 181 {
 182         uint32_t num, i, first = 0;
 183         const struct object_id *current = NULL;
 184
 185         if (open_pack_index(p) || !p->num_objects)
 186                 return;
 187
 188         num = p->num_objects;
 189         bsearch_pack(&ds->bin_pfx, p, &first);
 190
 191         /*
 192          * At this point, "first" is the location of the lowest object
 193          * with an object name that could match "bin_pfx".  See if we have
 194          * 0, 1 or more objects that actually match(es).
 195          */
 196         for (i = first; i < num && !ds->ambiguous; i++) {
 197                 struct object_id oid;
 198                 current = nth_packed_object_oid(&oid, p, i);
 199                 if (!match_sha(ds->len, ds->bin_pfx.hash, current->hash))
 200                         break;
 201                 update_candidates(ds, current);
 202         }
 203 }
 204
 205 static void find_short_packed_object(struct disambiguate_state *ds)
 206 {
 207         struct multi_pack_index *m;
 208         struct packed_git *p;
 209
 210         for (m = get_multi_pack_index(the_repository); m && !ds->ambiguous;
 211              m = m->next)
 212                 unique_in_midx(m, ds);
 213         for (p = get_packed_git(the_repository); p && !ds->ambiguous;
 214              p = p->next)
 215                 unique_in_pack(p, ds);
 216 }
 217
 218 #define SHORT_NAME_NOT_FOUND (-1)
 219 #define SHORT_NAME_AMBIGUOUS (-2)
 220
 221 static int finish_object_disambiguation(struct disambiguate_state *ds,
 222                                         struct object_id *oid)
 223 {
 224         if (ds->ambiguous)
 225                 return SHORT_NAME_AMBIGUOUS;
 226
 227         if (!ds->candidate_exists)
 228                 return SHORT_NAME_NOT_FOUND;
 229
 230         if (!ds->candidate_checked)
 231                 /*
 232                  * If this is the only candidate, there is no point
 233                  * calling the disambiguation hint callback.
 234                  *
 235                  * On the other hand, if the current candidate
 236                  * replaced an earlier candidate that did _not_ pass
 237                  * the disambiguation hint callback, then we do have
 238                  * more than one objects that match the short name
 239                  * given, so we should make sure this one matches;
 240                  * otherwise, if we discovered this one and the one
 241                  * that we previously discarded in the reverse order,
 242                  * we would end up showing different results in the
 243                  * same repository!
 244                  */
 245                 ds->candidate_ok = (!ds->disambiguate_fn_used ||
 246                                     ds->fn(&ds->candidate, ds->cb_data));
 247
 248         if (!ds->candidate_ok)
 249                 return SHORT_NAME_AMBIGUOUS;
 250
 251         oidcpy(oid, &ds->candidate);
 252         return 0;
 253 }
 254
 255 static int disambiguate_commit_only(const struct object_id *oid, void *cb_data_unused)
 256 {
 257         int kind = oid_object_info(the_repository, oid, NULL);
 258         return kind == OBJ_COMMIT;
 259 }
 260
 261 static int disambiguate_committish_only(const struct object_id *oid, void *cb_data_unused)
 262 {
 263         struct object *obj;
 264         int kind;
 265
 266         kind = oid_object_info(the_repository, oid, NULL);
 267         if (kind == OBJ_COMMIT)
 268                 return 1;
 269         if (kind != OBJ_TAG)
 270                 return 0;
 271
 272         /* We need to do this the hard way... */
 273         obj = deref_tag(the_repository, parse_object(the_repository, oid),
 274                         NULL, 0);
 275         if (obj && obj->type == OBJ_COMMIT)
 276                 return 1;
 277         return 0;
 278 }
 279
 280 static int disambiguate_tree_only(const struct object_id *oid, void *cb_data_unused)
 281 {
 282         int kind = oid_object_info(the_repository, oid, NULL);
 283         return kind == OBJ_TREE;
 284 }
 285
 286 static int disambiguate_treeish_only(const struct object_id *oid, void *cb_data_unused)
 287 {
 288         struct object *obj;
 289         int kind;
 290
 291         kind = oid_object_info(the_repository, oid, NULL);
 292         if (kind == OBJ_TREE || kind == OBJ_COMMIT)
 293                 return 1;
 294         if (kind != OBJ_TAG)
 295                 return 0;
 296
 297         /* We need to do this the hard way... */
 298         obj = deref_tag(the_repository, parse_object(the_repository, oid),
 299                         NULL, 0);
 300         if (obj && (obj->type == OBJ_TREE || obj->type == OBJ_COMMIT))
 301                 return 1;
 302         return 0;
 303 }
 304
 305 static int disambiguate_blob_only(const struct object_id *oid, void *cb_data_unused)
 306 {
 307         int kind = oid_object_info(the_repository, oid, NULL);
 308         return kind == OBJ_BLOB;
 309 }
 310
 311 static disambiguate_hint_fn default_disambiguate_hint;
 312
 313 int set_disambiguate_hint_config(const char *var, const char *value)
 314 {
 315         static const struct {
 316                 const char *name;
 317                 disambiguate_hint_fn fn;
 318         } hints[] = {
 319                 { "none", NULL },
 320                 { "commit", disambiguate_commit_only },
 321                 { "committish", disambiguate_committish_only },
 322                 { "tree", disambiguate_tree_only },
 323                 { "treeish", disambiguate_treeish_only },
 324                 { "blob", disambiguate_blob_only }
 325         };
 326         int i;
 327
 328         if (!value)
 329                 return config_error_nonbool(var);
 330
 331         for (i = 0; i < ARRAY_SIZE(hints); i++) {
 332                 if (!strcasecmp(value, hints[i].name)) {
 333                         default_disambiguate_hint = hints[i].fn;
 334                         return 0;
 335                 }
 336         }
 337
 338         return error("unknown hint type for '%s': %s", var, value);
 339 }
 340
 341 static int init_object_disambiguation(const char *name, int len,
 342                                       struct disambiguate_state *ds)
 343 {
 344         int i;
 345
 346         if (len < MINIMUM_ABBREV || len > the_hash_algo->hexsz)
 347                 return -1;
 348
 349         memset(ds, 0, sizeof(*ds));
 350
 351         for (i = 0; i < len ;i++) {
 352                 unsigned char c = name[i];
 353                 unsigned char val;
 354                 if (c >= '0' && c <= '9')
 355                         val = c - '0';
 356                 else if (c >= 'a' && c <= 'f')
 357                         val = c - 'a' + 10;
 358                 else if (c >= 'A' && c <='F') {
 359                         val = c - 'A' + 10;
 360                         c -= 'A' - 'a';
 361                 }
 362                 else
 363                         return -1;
 364                 ds->hex_pfx[i] = c;
 365                 if (!(i & 1))
 366                         val <<= 4;
 367                 ds->bin_pfx.hash[i >> 1] |= val;
 368         }
 369
 370         ds->len = len;
 371         ds->hex_pfx[len] = '\0';
 372         prepare_alt_odb(the_repository);
 373         return 0;
 374 }
 375
 376 static int show_ambiguous_object(const struct object_id *oid, void *data)
 377 {
 378         const struct disambiguate_state *ds = data;
 379         struct strbuf desc = STRBUF_INIT;
 380         int type;
 381
 382         if (ds->fn && !ds->fn(oid, ds->cb_data))
 383                 return 0;
 384
 385         type = oid_object_info(the_repository, oid, NULL);
 386         if (type == OBJ_COMMIT) {
 387                 struct commit *commit = lookup_commit(the_repository, oid);
 388                 if (commit) {
 389                         struct pretty_print_context pp = {0};
 390                         pp.date_mode.type = DATE_SHORT;
 391                         format_commit_message(commit, " %ad - %s", &desc, &pp);
 392                 }
 393         } else if (type == OBJ_TAG) {
 394                 struct tag *tag = lookup_tag(the_repository, oid);
 395                 if (!parse_tag(tag) && tag->tag)
 396                         strbuf_addf(&desc, " %s", tag->tag);
 397         }
 398
 399         advise("  %s %s%s",
 400                find_unique_abbrev(oid, DEFAULT_ABBREV),
 401                type_name(type) ? type_name(type) : "unknown type",
 402                desc.buf);
 403
 404         strbuf_release(&desc);
 405         return 0;
 406 }
 407
 408 static int collect_ambiguous(const struct object_id *oid, void *data)
 409 {
 410         oid_array_append(data, oid);
 411         return 0;
 412 }
 413
 414 static int sort_ambiguous(const void *a, const void *b)
 415 {
 416         int a_type = oid_object_info(the_repository, a, NULL);
 417         int b_type = oid_object_info(the_repository, b, NULL);
 418         int a_type_sort;
 419         int b_type_sort;
 420
 421         /*
 422          * Sorts by hash within the same object type, just as
 423          * oid_array_for_each_unique() would do.
 424          */
 425         if (a_type == b_type)
 426                 return oidcmp(a, b);
 427
 428         /*
 429          * Between object types show tags, then commits, and finally
 430          * trees and blobs.
 431          *
 432          * The object_type enum is commit, tree, blob, tag, but we
 433          * want tag, commit, tree blob. Cleverly (perhaps too
 434          * cleverly) do that with modulus, since the enum assigns 1 to
 435          * commit, so tag becomes 0.
 436          */
 437         a_type_sort = a_type % 4;
 438         b_type_sort = b_type % 4;
 439         return a_type_sort > b_type_sort ? 1 : -1;
 440 }
 441
 442 static int get_short_oid(const char *name, int len, struct object_id *oid,
 443                           unsigned flags)
 444 {
 445         int status;
 446         struct disambiguate_state ds;
 447         int quietly = !!(flags & GET_OID_QUIETLY);
 448
 449         if (init_object_disambiguation(name, len, &ds) < 0)
 450                 return -1;
 451
 452         if (HAS_MULTI_BITS(flags & GET_OID_DISAMBIGUATORS))
 453                 BUG("multiple get_short_oid disambiguator flags");
 454
 455         if (flags & GET_OID_COMMIT)
 456                 ds.fn = disambiguate_commit_only;
 457         else if (flags & GET_OID_COMMITTISH)
 458                 ds.fn = disambiguate_committish_only;
 459         else if (flags & GET_OID_TREE)
 460                 ds.fn = disambiguate_tree_only;
 461         else if (flags & GET_OID_TREEISH)
 462                 ds.fn = disambiguate_treeish_only;
 463         else if (flags & GET_OID_BLOB)
 464                 ds.fn = disambiguate_blob_only;
 465         else
 466                 ds.fn = default_disambiguate_hint;
 467
 468         find_short_object_filename(&ds);
 469         find_short_packed_object(&ds);
 470         status = finish_object_disambiguation(&ds, oid);
 471
 472         if (!quietly && (status == SHORT_NAME_AMBIGUOUS)) {
 473                 struct oid_array collect = OID_ARRAY_INIT;
 474
 475                 error(_("short SHA1 %s is ambiguous"), ds.hex_pfx);
 476
 477                 /*
 478                  * We may still have ambiguity if we simply saw a series of
 479                  * candidates that did not satisfy our hint function. In
 480                  * that case, we still want to show them, so disable the hint
 481                  * function entirely.
 482                  */
 483                 if (!ds.ambiguous)
 484                         ds.fn = NULL;
 485
 486                 advise(_("The candidates are:"));
 487                 for_each_abbrev(ds.hex_pfx, collect_ambiguous, &collect);
 488                 QSORT(collect.oid, collect.nr, sort_ambiguous);
 489
 490                 if (oid_array_for_each(&collect, show_ambiguous_object, &ds))
 491                         BUG("show_ambiguous_object shouldn't return non-zero");
 492                 oid_array_clear(&collect);
 493         }
 494
 495         return status;
 496 }
 497
 498 int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
 499 {
 500         struct oid_array collect = OID_ARRAY_INIT;
 501         struct disambiguate_state ds;
 502         int ret;
 503
 504         if (init_object_disambiguation(prefix, strlen(prefix), &ds) < 0)
 505                 return -1;
 506
 507         ds.always_call_fn = 1;
 508         ds.fn = collect_ambiguous;
 509         ds.cb_data = &collect;
 510         find_short_object_filename(&ds);
 511         find_short_packed_object(&ds);
 512
 513         ret = oid_array_for_each_unique(&collect, fn, cb_data);
 514         oid_array_clear(&collect);
 515         return ret;
 516 }
 517
 518 /*
 519  * Return the slot of the most-significant bit set in "val". There are various
 520  * ways to do this quickly with fls() or __builtin_clzl(), but speed is
 521  * probably not a big deal here.
 522  */
 523 static unsigned msb(unsigned long val)
 524 {
 525         unsigned r = 0;
 526         while (val >>= 1)
 527                 r++;
 528         return r;
 529 }
 530
 531 struct min_abbrev_data {
 532         unsigned int init_len;
 533         unsigned int cur_len;
 534         char *hex;
 535         const struct object_id *oid;
 536 };
 537
 538 static inline char get_hex_char_from_oid(const struct object_id *oid,
 539                                          unsigned int pos)
 540 {
 541         static const char hex[] = "0123456789abcdef";
 542
 543         if ((pos & 1) == 0)
 544                 return hex[oid->hash[pos >> 1] >> 4];
 545         else
 546                 return hex[oid->hash[pos >> 1] & 0xf];
 547 }
 548
 549 static int extend_abbrev_len(const struct object_id *oid, void *cb_data)
 550 {
 551         struct min_abbrev_data *mad = cb_data;
 552
 553         unsigned int i = mad->init_len;
 554         while (mad->hex[i] && mad->hex[i] == get_hex_char_from_oid(oid, i))
 555                 i++;
 556
 557         if (i < GIT_MAX_RAWSZ && i >= mad->cur_len)
 558                 mad->cur_len = i + 1;
 559
 560         return 0;
 561 }
 562
 563 static void find_abbrev_len_for_midx(struct multi_pack_index *m,
 564                                      struct min_abbrev_data *mad)
 565 {
 566         int match = 0;
 567         uint32_t num, first = 0;
 568         struct object_id oid;
 569         const struct object_id *mad_oid;
 570
 571         if (!m->num_objects)
 572                 return;
 573
 574         num = m->num_objects;
 575         mad_oid = mad->oid;
 576         match = bsearch_midx(mad_oid, m, &first);
 577
 578         /*
 579          * first is now the position in the packfile where we would insert
 580          * mad->hash if it does not exist (or the position of mad->hash if
 581          * it does exist). Hence, we consider a maximum of two objects
 582          * nearby for the abbreviation length.
 583          */
 584         mad->init_len = 0;
 585         if (!match) {
 586                 if (nth_midxed_object_oid(&oid, m, first))
 587                         extend_abbrev_len(&oid, mad);
 588         } else if (first < num - 1) {
 589                 if (nth_midxed_object_oid(&oid, m, first + 1))
 590                         extend_abbrev_len(&oid, mad);
 591         }
 592         if (first > 0) {
 593                 if (nth_midxed_object_oid(&oid, m, first - 1))
 594                         extend_abbrev_len(&oid, mad);
 595         }
 596         mad->init_len = mad->cur_len;
 597 }
 598
 599 static void find_abbrev_len_for_pack(struct packed_git *p,
 600                                      struct min_abbrev_data *mad)
 601 {
 602         int match = 0;
 603         uint32_t num, first = 0;
 604         struct object_id oid;
 605         const struct object_id *mad_oid;
 606
 607         if (open_pack_index(p) || !p->num_objects)
 608                 return;
 609
 610         num = p->num_objects;
 611         mad_oid = mad->oid;
 612         match = bsearch_pack(mad_oid, p, &first);
 613
 614         /*
 615          * first is now the position in the packfile where we would insert
 616          * mad->hash if it does not exist (or the position of mad->hash if
 617          * it does exist). Hence, we consider a maximum of two objects
 618          * nearby for the abbreviation length.
 619          */
 620         mad->init_len = 0;
 621         if (!match) {
 622                 if (nth_packed_object_oid(&oid, p, first))
 623                         extend_abbrev_len(&oid, mad);
 624         } else if (first < num - 1) {
 625                 if (nth_packed_object_oid(&oid, p, first + 1))
 626                         extend_abbrev_len(&oid, mad);
 627         }
 628         if (first > 0) {
 629                 if (nth_packed_object_oid(&oid, p, first - 1))
 630                         extend_abbrev_len(&oid, mad);
 631         }
 632         mad->init_len = mad->cur_len;
 633 }
 634
 635 static void find_abbrev_len_packed(struct min_abbrev_data *mad)
 636 {
 637         struct multi_pack_index *m;
 638         struct packed_git *p;
 639
 640         for (m = get_multi_pack_index(the_repository); m; m = m->next)
 641                 find_abbrev_len_for_midx(m, mad);
 642         for (p = get_packed_git(the_repository); p; p = p->next)
 643                 find_abbrev_len_for_pack(p, mad);
 644 }
 645
 646 int find_unique_abbrev_r(char *hex, const struct object_id *oid, int len)
 647 {
 648         struct disambiguate_state ds;
 649         struct min_abbrev_data mad;
 650         struct object_id oid_ret;
 651         const unsigned hexsz = the_hash_algo->hexsz;
 652
 653         if (len < 0) {
 654                 unsigned long count = approximate_object_count();
 655                 /*
 656                  * Add one because the MSB only tells us the highest bit set,
 657                  * not including the value of all the _other_ bits (so "15"
 658                  * is only one off of 2^4, but the MSB is the 3rd bit.
 659                  */
 660                 len = msb(count) + 1;
 661                 /*
 662                  * We now know we have on the order of 2^len objects, which
 663                  * expects a collision at 2^(len/2). But we also care about hex
 664                  * chars, not bits, and there are 4 bits per hex. So all
 665                  * together we need to divide by 2 and round up.
 666                  */
 667                 len = DIV_ROUND_UP(len, 2);
 668                 /*
 669                  * For very small repos, we stick with our regular fallback.
 670                  */
 671                 if (len < FALLBACK_DEFAULT_ABBREV)
 672                         len = FALLBACK_DEFAULT_ABBREV;
 673         }
 674
 675         oid_to_hex_r(hex, oid);
 676         if (len == hexsz || !len)
 677                 return hexsz;
 678
 679         mad.init_len = len;
 680         mad.cur_len = len;
 681         mad.hex = hex;
 682         mad.oid = oid;
 683
 684         find_abbrev_len_packed(&mad);
 685
 686         if (init_object_disambiguation(hex, mad.cur_len, &ds) < 0)
 687                 return -1;
 688
 689         ds.fn = extend_abbrev_len;
 690         ds.always_call_fn = 1;
 691         ds.cb_data = (void *)&mad;
 692
 693         find_short_object_filename(&ds);
 694         (void)finish_object_disambiguation(&ds, &oid_ret);
 695
 696         hex[mad.cur_len] = 0;
 697         return mad.cur_len;
 698 }
 699
 700 const char *find_unique_abbrev(const struct object_id *oid, int len)
 701 {
 702         static int bufno;
 703         static char hexbuffer[4][GIT_MAX_HEXSZ + 1];
 704         char *hex = hexbuffer[bufno];
 705         bufno = (bufno + 1) % ARRAY_SIZE(hexbuffer);
 706         find_unique_abbrev_r(hex, oid, len);
 707         return hex;
 708 }
 709
 710 static int ambiguous_path(const char *path, int len)
 711 {
 712         int slash = 1;
 713         int cnt;
 714
 715         for (cnt = 0; cnt < len; cnt++) {
 716                 switch (*path++) {
 717                 case '\0':
 718                         break;
 719                 case '/':
 720                         if (slash)
 721                                 break;
 722                         slash = 1;
 723                         continue;
 724                 case '.':
 725                         continue;
 726                 default:
 727                         slash = 0;
 728                         continue;
 729                 }
 730                 break;
 731         }
 732         return slash;
 733 }
 734
 735 static inline int at_mark(const char *string, int len,
 736                           const char **suffix, int nr)
 737 {
 738         int i;
 739
 740         for (i = 0; i < nr; i++) {
 741                 int suffix_len = strlen(suffix[i]);
 742                 if (suffix_len <= len
 743                     && !strncasecmp(string, suffix[i], suffix_len))
 744                         return suffix_len;
 745         }
 746         return 0;
 747 }
 748
 749 static inline int upstream_mark(const char *string, int len)
 750 {
 751         const char *suffix[] = { "@{upstream}", "@{u}" };
 752         return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
 753 }
 754
 755 static inline int push_mark(const char *string, int len)
 756 {
 757         const char *suffix[] = { "@{push}" };
 758         return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
 759 }
 760
 761 static int get_oid_1(const char *name, int len, struct object_id *oid, unsigned lookup_flags);
 762 static int interpret_nth_prior_checkout(const char *name, int namelen, struct strbuf *buf);
 763
 764 static int get_oid_basic(const char *str, int len, struct object_id *oid,
 765                           unsigned int flags)
 766 {
 767         static const char *warn_msg = "refname '%.*s' is ambiguous.";
 768         static const char *object_name_msg = N_(
 769         "Git normally never creates a ref that ends with 40 hex characters\n"
 770         "because it will be ignored when you just specify 40-hex. These refs\n"
 771         "may be created by mistake. For example,\n"
 772         "\n"
 773         "  git checkout -b $br $(git rev-parse ...)\n"
 774         "\n"
 775         "where \"$br\" is somehow empty and a 40-hex ref is created. Please\n"
 776         "examine these refs and maybe delete them. Turn this message off by\n"
 777         "running \"git config advice.objectNameWarning false\"");
 778         struct object_id tmp_oid;
 779         char *real_ref = NULL;
 780         int refs_found = 0;
 781         int at, reflog_len, nth_prior = 0;
 782
 783         if (len == the_hash_algo->hexsz && !get_oid_hex(str, oid)) {
 784                 if (warn_ambiguous_refs && warn_on_object_refname_ambiguity) {
 785                         refs_found = dwim_ref(str, len, &tmp_oid, &real_ref);
 786                         if (refs_found > 0) {
 787                                 warning(warn_msg, len, str);
 788                                 if (advice_object_name_warning)
 789                                         fprintf(stderr, "%s\n", _(object_name_msg));
 790                         }
 791                         free(real_ref);
 792                 }
 793                 return 0;
 794         }
 795
 796         /* basic@{time or number or -number} format to query ref-log */
 797         reflog_len = at = 0;
 798         if (len && str[len-1] == '}') {
 799                 for (at = len-4; at >= 0; at--) {
 800                         if (str[at] == '@' && str[at+1] == '{') {
 801                                 if (str[at+2] == '-') {
 802                                         if (at != 0)
 803                                                 /* @{-N} not at start */
 804                                                 return -1;
 805                                         nth_prior = 1;
 806                                         continue;
 807                                 }
 808                                 if (!upstream_mark(str + at, len - at) &&
 809                                     !push_mark(str + at, len - at)) {
 810                                         reflog_len = (len-1) - (at+2);
 811                                         len = at;
 812                                 }
 813                                 break;
 814                         }
 815                 }
 816         }
 817
 818         /* Accept only unambiguous ref paths. */
 819         if (len && ambiguous_path(str, len))
 820                 return -1;
 821
 822         if (nth_prior) {
 823                 struct strbuf buf = STRBUF_INIT;
 824                 int detached;
 825
 826                 if (interpret_nth_prior_checkout(str, len, &buf) > 0) {
 827                         detached = (buf.len == the_hash_algo->hexsz && !get_oid_hex(buf.buf, oid));
 828                         strbuf_release(&buf);
 829                         if (detached)
 830                                 return 0;
 831                 }
 832         }
 833
 834         if (!len && reflog_len)
 835                 /* allow "@{...}" to mean the current branch reflog */
 836                 refs_found = dwim_ref("HEAD", 4, oid, &real_ref);
 837         else if (reflog_len)
 838                 refs_found = dwim_log(str, len, oid, &real_ref);
 839         else
 840                 refs_found = dwim_ref(str, len, oid, &real_ref);
 841
 842         if (!refs_found)
 843                 return -1;
 844
 845         if (warn_ambiguous_refs && !(flags & GET_OID_QUIETLY) &&
 846             (refs_found > 1 ||
 847              !get_short_oid(str, len, &tmp_oid, GET_OID_QUIETLY)))
 848                 warning(warn_msg, len, str);
 849
 850         if (reflog_len) {
 851                 int nth, i;
 852                 timestamp_t at_time;
 853                 timestamp_t co_time;
 854                 int co_tz, co_cnt;
 855
 856                 /* Is it asking for N-th entry, or approxidate? */
 857                 for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 858                         char ch = str[at+2+i];
 859                         if ('0' <= ch && ch <= '9')
 860                                 nth = nth * 10 + ch - '0';
 861                         else
 862                                 nth = -1;
 863                 }
 864                 if (100000000 <= nth) {
 865                         at_time = nth;
 866                         nth = -1;
 867                 } else if (0 <= nth)
 868                         at_time = 0;
 869                 else {
 870                         int errors = 0;
 871                         char *tmp = xstrndup(str + at + 2, reflog_len);
 872                         at_time = approxidate_careful(tmp, &errors);
 873                         free(tmp);
 874                         if (errors) {
 875                                 free(real_ref);
 876                                 return -1;
 877                         }
 878                 }
 879                 if (read_ref_at(real_ref, flags, at_time, nth, oid, NULL,
 880                                 &co_time, &co_tz, &co_cnt)) {
 881                         if (!len) {
 882                                 if (starts_with(real_ref, "refs/heads/")) {
 883                                         str = real_ref + 11;
 884                                         len = strlen(real_ref + 11);
 885                                 } else {
 886                                         /* detached HEAD */
 887                                         str = "HEAD";
 888                                         len = 4;
 889                                 }
 890                         }
 891                         if (at_time) {
 892                                 if (!(flags & GET_OID_QUIETLY)) {
 893                                         warning("Log for '%.*s' only goes "
 894                                                 "back to %s.", len, str,
 895                                                 show_date(co_time, co_tz, DATE_MODE(RFC2822)));
 896                                 }
 897                         } else {
 898                                 if (flags & GET_OID_QUIETLY) {
 899                                         exit(128);
 900                                 }
 901                                 die("Log for '%.*s' only has %d entries.",
 902                                     len, str, co_cnt);
 903                         }
 904                 }
 905         }
 906
 907         free(real_ref);
 908         return 0;
 909 }
 910
 911 static int get_parent(const char *name, int len,
 912                       struct object_id *result, int idx)
 913 {
 914         struct object_id oid;
 915         int ret = get_oid_1(name, len, &oid, GET_OID_COMMITTISH);
 916         struct commit *commit;
 917         struct commit_list *p;
 918
 919         if (ret)
 920                 return ret;
 921         commit = lookup_commit_reference(the_repository, &oid);
 922         if (parse_commit(commit))
 923                 return -1;
 924         if (!idx) {
 925                 oidcpy(result, &commit->object.oid);
 926                 return 0;
 927         }
 928         p = commit->parents;
 929         while (p) {
 930                 if (!--idx) {
 931                         oidcpy(result, &p->item->object.oid);
 932                         return 0;
 933                 }
 934                 p = p->next;
 935         }
 936         return -1;
 937 }
 938
 939 static int get_nth_ancestor(const char *name, int len,
 940                             struct object_id *result, int generation)
 941 {
 942         struct object_id oid;
 943         struct commit *commit;
 944         int ret;
 945
 946         ret = get_oid_1(name, len, &oid, GET_OID_COMMITTISH);
 947         if (ret)
 948                 return ret;
 949         commit = lookup_commit_reference(the_repository, &oid);
 950         if (!commit)
 951                 return -1;
 952
 953         while (generation--) {
 954                 if (parse_commit(commit) || !commit->parents)
 955                         return -1;
 956                 commit = commit->parents->item;
 957         }
 958         oidcpy(result, &commit->object.oid);
 959         return 0;
 960 }
 961
 962 struct object *peel_to_type(const char *name, int namelen,
 963                             struct object *o, enum object_type expected_type)
 964 {
 965         if (name && !namelen)
 966                 namelen = strlen(name);
 967         while (1) {
 968                 if (!o || (!o->parsed && !parse_object(the_repository, &o->oid)))
 969                         return NULL;
 970                 if (expected_type == OBJ_ANY || o->type == expected_type)
 971                         return o;
 972                 if (o->type == OBJ_TAG)
 973                         o = ((struct tag*) o)->tagged;
 974                 else if (o->type == OBJ_COMMIT)
 975                         o = &(get_commit_tree(((struct commit *)o))->object);
 976                 else {
 977                         if (name)
 978                                 error("%.*s: expected %s type, but the object "
 979                                       "dereferences to %s type",
 980                                       namelen, name, type_name(expected_type),
 981                                       type_name(o->type));
 982                         return NULL;
 983                 }
 984         }
 985 }
 986
 987 static int peel_onion(const char *name, int len, struct object_id *oid,
 988                       unsigned lookup_flags)
 989 {
 990         struct object_id outer;
 991         const char *sp;
 992         unsigned int expected_type = 0;
 993         struct object *o;
 994
 995         /*
 996          * "ref^{type}" dereferences ref repeatedly until you cannot
 997          * dereference anymore, or you get an object of given type,
 998          * whichever comes first.  "ref^{}" means just dereference
 999          * tags until you get a non-tag.  "ref^0" is a shorthand for
1000          * "ref^{commit}".  "commit^{tree}" could be used to find the
1001          * top-level tree of the given commit.
1002          */
1003         if (len < 4 || name[len-1] != '}')
1004                 return -1;
1005
1006         for (sp = name + len - 1; name <= sp; sp--) {
1007                 int ch = *sp;
1008                 if (ch == '{' && name < sp && sp[-1] == '^')
1009                         break;
1010         }
1011         if (sp <= name)
1012                 return -1;
1013
1014         sp++; /* beginning of type name, or closing brace for empty */
1015         if (starts_with(sp, "commit}"))
1016                 expected_type = OBJ_COMMIT;
1017         else if (starts_with(sp, "tag}"))
1018                 expected_type = OBJ_TAG;
1019         else if (starts_with(sp, "tree}"))
1020                 expected_type = OBJ_TREE;
1021         else if (starts_with(sp, "blob}"))
1022                 expected_type = OBJ_BLOB;
1023         else if (starts_with(sp, "object}"))
1024                 expected_type = OBJ_ANY;
1025         else if (sp[0] == '}')
1026                 expected_type = OBJ_NONE;
1027         else if (sp[0] == '/')
1028                 expected_type = OBJ_COMMIT;
1029         else
1030                 return -1;
1031
1032         lookup_flags &= ~GET_OID_DISAMBIGUATORS;
1033         if (expected_type == OBJ_COMMIT)
1034                 lookup_flags |= GET_OID_COMMITTISH;
1035         else if (expected_type == OBJ_TREE)
1036                 lookup_flags |= GET_OID_TREEISH;
1037
1038         if (get_oid_1(name, sp - name - 2, &outer, lookup_flags))
1039                 return -1;
1040
1041         o = parse_object(the_repository, &outer);
1042         if (!o)
1043                 return -1;
1044         if (!expected_type) {
1045                 o = deref_tag(the_repository, o, name, sp - name - 2);
1046                 if (!o || (!o->parsed && !parse_object(the_repository, &o->oid)))
1047                         return -1;
1048                 oidcpy(oid, &o->oid);
1049                 return 0;
1050         }
1051
1052         /*
1053          * At this point, the syntax look correct, so
1054          * if we do not get the needed object, we should
1055          * barf.
1056          */
1057         o = peel_to_type(name, len, o, expected_type);
1058         if (!o)
1059                 return -1;
1060
1061         oidcpy(oid, &o->oid);
1062         if (sp[0] == '/') {
1063                 /* "$commit^{/foo}" */
1064                 char *prefix;
1065                 int ret;
1066                 struct commit_list *list = NULL;
1067
1068                 /*
1069                  * $commit^{/}. Some regex implementation may reject.
1070                  * We don't need regex anyway. '' pattern always matches.
1071                  */
1072                 if (sp[1] == '}')
1073                         return 0;
1074
1075                 prefix = xstrndup(sp + 1, name + len - 1 - (sp + 1));
1076                 commit_list_insert((struct commit *)o, &list);
1077                 ret = get_oid_oneline(prefix, oid, list);
1078                 free(prefix);
1079                 return ret;
1080         }
1081         return 0;
1082 }
1083
1084 static int get_describe_name(const char *name, int len, struct object_id *oid)
1085 {
1086         const char *cp;
1087         unsigned flags = GET_OID_QUIETLY | GET_OID_COMMIT;
1088
1089         for (cp = name + len - 1; name + 2 <= cp; cp--) {
1090                 char ch = *cp;
1091                 if (!isxdigit(ch)) {
1092                         /* We must be looking at g in "SOMETHING-g"
1093                          * for it to be describe output.
1094                          */
1095                         if (ch == 'g' && cp[-1] == '-') {
1096                                 cp++;
1097                                 len -= cp - name;
1098                                 return get_short_oid(cp, len, oid, flags);
1099                         }
1100                 }
1101         }
1102         return -1;
1103 }
1104
1105 static int get_oid_1(const char *name, int len, struct object_id *oid, unsigned lookup_flags)
1106 {
1107         int ret, has_suffix;
1108         const char *cp;
1109
1110         /*
1111          * "name~3" is "name^^^", "name~" is "name~1", and "name^" is "name^1".
1112          */
1113         has_suffix = 0;
1114         for (cp = name + len - 1; name <= cp; cp--) {
1115                 int ch = *cp;
1116                 if ('0' <= ch && ch <= '9')
1117                         continue;
1118                 if (ch == '~' || ch == '^')
1119                         has_suffix = ch;
1120                 break;
1121         }
1122
1123         if (has_suffix) {
1124                 int num = 0;
1125                 int len1 = cp - name;
1126                 cp++;
1127                 while (cp < name + len)
1128                         num = num * 10 + *cp++ - '0';
1129                 if (!num && len1 == len - 1)
1130                         num = 1;
1131                 if (has_suffix == '^')
1132                         return get_parent(name, len1, oid, num);
1133                 /* else if (has_suffix == '~') -- goes without saying */
1134                 return get_nth_ancestor(name, len1, oid, num);
1135         }
1136
1137         ret = peel_onion(name, len, oid, lookup_flags);
1138         if (!ret)
1139                 return 0;
1140
1141         ret = get_oid_basic(name, len, oid, lookup_flags);
1142         if (!ret)
1143                 return 0;
1144
1145         /* It could be describe output that is "SOMETHING-gXXXX" */
1146         ret = get_describe_name(name, len, oid);
1147         if (!ret)
1148                 return 0;
1149
1150         return get_short_oid(name, len, oid, lookup_flags);
1151 }
1152
1153 /*
1154  * This interprets names like ':/Initial revision of "git"' by searching
1155  * through history and returning the first commit whose message starts
1156  * the given regular expression.
1157  *
1158  * For negative-matching, prefix the pattern-part with '!-', like: ':/!-WIP'.
1159  *
1160  * For a literal '!' character at the beginning of a pattern, you have to repeat
1161  * that, like: ':/!!foo'
1162  *
1163  * For future extension, all other sequences beginning with ':/!' are reserved.
1164  */
1165
1166 /* Remember to update object flag allocation in object.h */
1167 #define ONELINE_SEEN (1u<<20)
1168
1169 static int handle_one_ref(const char *path, const struct object_id *oid,
1170                           int flag, void *cb_data)
1171 {
1172         struct commit_list **list = cb_data;
1173         struct object *object = parse_object(the_repository, oid);
1174         if (!object)
1175                 return 0;
1176         if (object->type == OBJ_TAG) {
1177                 object = deref_tag(the_repository, object, path,
1178                                    strlen(path));
1179                 if (!object)
1180                         return 0;
1181         }
1182         if (object->type != OBJ_COMMIT)
1183                 return 0;
1184         commit_list_insert((struct commit *)object, list);
1185         return 0;
1186 }
1187
1188 static int get_oid_oneline(const char *prefix, struct object_id *oid,
1189                             struct commit_list *list)
1190 {
1191         struct commit_list *backup = NULL, *l;
1192         int found = 0;
1193         int negative = 0;
1194         regex_t regex;
1195
1196         if (prefix[0] == '!') {
1197                 prefix++;
1198
1199                 if (prefix[0] == '-') {
1200                         prefix++;
1201                         negative = 1;
1202                 } else if (prefix[0] != '!') {
1203                         return -1;
1204                 }
1205         }
1206
1207         if (regcomp(&regex, prefix, REG_EXTENDED))
1208                 return -1;
1209
1210         for (l = list; l; l = l->next) {
1211                 l->item->object.flags |= ONELINE_SEEN;
1212                 commit_list_insert(l->item, &backup);
1213         }
1214         while (list) {
1215                 const char *p, *buf;
1216                 struct commit *commit;
1217                 int matches;
1218
1219                 commit = pop_most_recent_commit(&list, ONELINE_SEEN);
1220                 if (!parse_object(the_repository, &commit->object.oid))
1221                         continue;
1222                 buf = get_commit_buffer(commit, NULL);
1223                 p = strstr(buf, "\n\n");
1224                 matches = negative ^ (p && !regexec(&regex, p + 2, 0, NULL, 0));
1225                 unuse_commit_buffer(commit, buf);
1226
1227                 if (matches) {
1228                         oidcpy(oid, &commit->object.oid);
1229                         found = 1;
1230                         break;
1231                 }
1232         }
1233         regfree(&regex);
1234         free_commit_list(list);
1235         for (l = backup; l; l = l->next)
1236                 clear_commit_marks(l->item, ONELINE_SEEN);
1237         free_commit_list(backup);
1238         return found ? 0 : -1;
1239 }
1240
1241 struct grab_nth_branch_switch_cbdata {
1242         int remaining;
1243         struct strbuf buf;
1244 };
1245
1246 static int grab_nth_branch_switch(struct object_id *ooid, struct object_id *noid,
1247                                   const char *email, timestamp_t timestamp, int tz,
1248                                   const char *message, void *cb_data)
1249 {
1250         struct grab_nth_branch_switch_cbdata *cb = cb_data;
1251         const char *match = NULL, *target = NULL;
1252         size_t len;
1253
1254         if (skip_prefix(message, "checkout: moving from ", &match))
1255                 target = strstr(match, " to ");
1256
1257         if (!match || !target)
1258                 return 0;
1259         if (--(cb->remaining) == 0) {
1260                 len = target - match;
1261                 strbuf_reset(&cb->buf);
1262                 strbuf_add(&cb->buf, match, len);
1263                 return 1; /* we are done */
1264         }
1265         return 0;
1266 }
1267
1268 /*
1269  * Parse @{-N} syntax, return the number of characters parsed
1270  * if successful; otherwise signal an error with negative value.
1271  */
1272 static int interpret_nth_prior_checkout(const char *name, int namelen,
1273                                         struct strbuf *buf)
1274 {
1275         long nth;
1276         int retval;
1277         struct grab_nth_branch_switch_cbdata cb;
1278         const char *brace;
1279         char *num_end;
1280
1281         if (namelen < 4)
1282                 return -1;
1283         if (name[0] != '@' || name[1] != '{' || name[2] != '-')
1284                 return -1;
1285         brace = memchr(name, '}', namelen);
1286         if (!brace)
1287                 return -1;
1288         nth = strtol(name + 3, &num_end, 10);
1289         if (num_end != brace)
1290                 return -1;
1291         if (nth <= 0)
1292                 return -1;
1293         cb.remaining = nth;
1294         strbuf_init(&cb.buf, 20);
1295
1296         retval = 0;
1297         if (0 < for_each_reflog_ent_reverse("HEAD", grab_nth_branch_switch, &cb)) {
1298                 strbuf_reset(buf);
1299                 strbuf_addbuf(buf, &cb.buf);
1300                 retval = brace - name + 1;
1301         }
1302
1303         strbuf_release(&cb.buf);
1304         return retval;
1305 }
1306
1307 int get_oid_mb(const char *name, struct object_id *oid)
1308 {
1309         struct commit *one, *two;
1310         struct commit_list *mbs;
1311         struct object_id oid_tmp;
1312         const char *dots;
1313         int st;
1314
1315         dots = strstr(name, "...");
1316         if (!dots)
1317                 return get_oid(name, oid);
1318         if (dots == name)
1319                 st = get_oid("HEAD", &oid_tmp);
1320         else {
1321                 struct strbuf sb;
1322                 strbuf_init(&sb, dots - name);
1323                 strbuf_add(&sb, name, dots - name);
1324                 st = get_oid_committish(sb.buf, &oid_tmp);
1325                 strbuf_release(&sb);
1326         }
1327         if (st)
1328                 return st;
1329         one = lookup_commit_reference_gently(the_repository, &oid_tmp, 0);
1330         if (!one)
1331                 return -1;
1332
1333         if (get_oid_committish(dots[3] ? (dots + 3) : "HEAD", &oid_tmp))
1334                 return -1;
1335         two = lookup_commit_reference_gently(the_repository, &oid_tmp, 0);
1336         if (!two)
1337                 return -1;
1338         mbs = get_merge_bases(one, two);
1339         if (!mbs || mbs->next)
1340                 st = -1;
1341         else {
1342                 st = 0;
1343                 oidcpy(oid, &mbs->item->object.oid);
1344         }
1345         free_commit_list(mbs);
1346         return st;
1347 }
1348
1349 /* parse @something syntax, when 'something' is not {.*} */
1350 static int interpret_empty_at(const char *name, int namelen, int len, struct strbuf *buf)
1351 {
1352         const char *next;
1353
1354         if (len || name[1] == '{')
1355                 return -1;
1356
1357         /* make sure it's a single @, or @@{.*}, not @foo */
1358         next = memchr(name + len + 1, '@', namelen - len - 1);
1359         if (next && next[1] != '{')
1360                 return -1;
1361         if (!next)
1362                 next = name + namelen;
1363         if (next != name + 1)
1364                 return -1;
1365
1366         strbuf_reset(buf);
1367         strbuf_add(buf, "HEAD", 4);
1368         return 1;
1369 }
1370
1371 static int reinterpret(const char *name, int namelen, int len,
1372                        struct strbuf *buf, unsigned allowed)
1373 {
1374         /* we have extra data, which might need further processing */
1375         struct strbuf tmp = STRBUF_INIT;
1376         int used = buf->len;
1377         int ret;
1378
1379         strbuf_add(buf, name + len, namelen - len);
1380         ret = interpret_branch_name(buf->buf, buf->len, &tmp, allowed);
1381         /* that data was not interpreted, remove our cruft */
1382         if (ret < 0) {
1383                 strbuf_setlen(buf, used);
1384                 return len;
1385         }
1386         strbuf_reset(buf);
1387         strbuf_addbuf(buf, &tmp);
1388         strbuf_release(&tmp);
1389         /* tweak for size of {-N} versus expanded ref name */
1390         return ret - used + len;
1391 }
1392
1393 static void set_shortened_ref(struct strbuf *buf, const char *ref)
1394 {
1395         char *s = shorten_unambiguous_ref(ref, 0);
1396         strbuf_reset(buf);
1397         strbuf_addstr(buf, s);
1398         free(s);
1399 }
1400
1401 static int branch_interpret_allowed(const char *refname, unsigned allowed)
1402 {
1403         if (!allowed)
1404                 return 1;
1405
1406         if ((allowed & INTERPRET_BRANCH_LOCAL) &&
1407             starts_with(refname, "refs/heads/"))
1408                 return 1;
1409         if ((allowed & INTERPRET_BRANCH_REMOTE) &&
1410             starts_with(refname, "refs/remotes/"))
1411                 return 1;
1412
1413         return 0;
1414 }
1415
1416 static int interpret_branch_mark(const char *name, int namelen,
1417                                  int at, struct strbuf *buf,
1418                                  int (*get_mark)(const char *, int),
1419                                  const char *(*get_data)(struct branch *,
1420                                                          struct strbuf *),
1421                                  unsigned allowed)
1422 {
1423         int len;
1424         struct branch *branch;
1425         struct strbuf err = STRBUF_INIT;
1426         const char *value;
1427
1428         len = get_mark(name + at, namelen - at);
1429         if (!len)
1430                 return -1;
1431
1432         if (memchr(name, ':', at))
1433                 return -1;
1434
1435         if (at) {
1436                 char *name_str = xmemdupz(name, at);
1437                 branch = branch_get(name_str);
1438                 free(name_str);
1439         } else
1440                 branch = branch_get(NULL);
1441
1442         value = get_data(branch, &err);
1443         if (!value)
1444                 die("%s", err.buf);
1445
1446         if (!branch_interpret_allowed(value, allowed))
1447                 return -1;
1448
1449         set_shortened_ref(buf, value);
1450         return len + at;
1451 }
1452
1453 int interpret_branch_name(const char *name, int namelen, struct strbuf *buf,
1454                           unsigned allowed)
1455 {
1456         char *at;
1457         const char *start;
1458         int len;
1459
1460         if (!namelen)
1461                 namelen = strlen(name);
1462
1463         if (!allowed || (allowed & INTERPRET_BRANCH_LOCAL)) {
1464                 len = interpret_nth_prior_checkout(name, namelen, buf);
1465                 if (!len) {
1466                         return len; /* syntax Ok, not enough switches */
1467                 } else if (len > 0) {
1468                         if (len == namelen)
1469                                 return len; /* consumed all */
1470                         else
1471                                 return reinterpret(name, namelen, len, buf, allowed);
1472                 }
1473         }
1474
1475         for (start = name;
1476              (at = memchr(start, '@', namelen - (start - name)));
1477              start = at + 1) {
1478
1479                 if (!allowed || (allowed & INTERPRET_BRANCH_HEAD)) {
1480                         len = interpret_empty_at(name, namelen, at - name, buf);
1481                         if (len > 0)
1482                                 return reinterpret(name, namelen, len, buf,
1483                                                    allowed);
1484                 }
1485
1486                 len = interpret_branch_mark(name, namelen, at - name, buf,
1487                                             upstream_mark, branch_get_upstream,
1488                                             allowed);
1489                 if (len > 0)
1490                         return len;
1491
1492                 len = interpret_branch_mark(name, namelen, at - name, buf,
1493                                             push_mark, branch_get_push,
1494                                             allowed);
1495                 if (len > 0)
1496                         return len;
1497         }
1498
1499         return -1;
1500 }
1501
1502 void strbuf_branchname(struct strbuf *sb, const char *name, unsigned allowed)
1503 {
1504         int len = strlen(name);
1505         int used = interpret_branch_name(name, len, sb, allowed);
1506
1507         if (used < 0)
1508                 used = 0;
1509         strbuf_add(sb, name + used, len - used);
1510 }
1511
1512 int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
1513 {
1514         if (startup_info->have_repository)
1515                 strbuf_branchname(sb, name, INTERPRET_BRANCH_LOCAL);
1516         else
1517                 strbuf_addstr(sb, name);
1518
1519         /*
1520          * This splice must be done even if we end up rejecting the
1521          * name; builtin/branch.c::copy_or_rename_branch() still wants
1522          * to see what the name expanded to so that "branch -m" can be
1523          * used as a tool to correct earlier mistakes.
1524          */
1525         strbuf_splice(sb, 0, 0, "refs/heads/", 11);
1526
1527         if (*name == '-' ||
1528             !strcmp(sb->buf, "refs/heads/HEAD"))
1529                 return -1;
1530
1531         return check_refname_format(sb->buf, 0);
1532 }
1533
1534 /*
1535  * This is like "get_oid_basic()", except it allows "object ID expressions",
1536  * notably "xyz^" for "parent of xyz"
1537  */
1538 int get_oid(const char *name, struct object_id *oid)
1539 {
1540         struct object_context unused;
1541         return get_oid_with_context(name, 0, oid, &unused);
1542 }
1543
1544
1545 /*
1546  * Many callers know that the user meant to name a commit-ish by
1547  * syntactical positions where the object name appears.  Calling this
1548  * function allows the machinery to disambiguate shorter-than-unique
1549  * abbreviated object names between commit-ish and others.
1550  *
1551  * Note that this does NOT error out when the named object is not a
1552  * commit-ish. It is merely to give a hint to the disambiguation
1553  * machinery.
1554  */
1555 int get_oid_committish(const char *name, struct object_id *oid)
1556 {
1557         struct object_context unused;
1558         return get_oid_with_context(name, GET_OID_COMMITTISH,
1559                                     oid, &unused);
1560 }
1561
1562 int get_oid_treeish(const char *name, struct object_id *oid)
1563 {
1564         struct object_context unused;
1565         return get_oid_with_context(name, GET_OID_TREEISH,
1566                                     oid, &unused);
1567 }
1568
1569 int get_oid_commit(const char *name, struct object_id *oid)
1570 {
1571         struct object_context unused;
1572         return get_oid_with_context(name, GET_OID_COMMIT,
1573                                     oid, &unused);
1574 }
1575
1576 int get_oid_tree(const char *name, struct object_id *oid)
1577 {
1578         struct object_context unused;
1579         return get_oid_with_context(name, GET_OID_TREE,
1580                                     oid, &unused);
1581 }
1582
1583 int get_oid_blob(const char *name, struct object_id *oid)
1584 {
1585         struct object_context unused;
1586         return get_oid_with_context(name, GET_OID_BLOB,
1587                                     oid, &unused);
1588 }
1589
1590 /* Must be called only when object_name:filename doesn't exist. */
1591 static void diagnose_invalid_oid_path(const char *prefix,
1592                                       const char *filename,
1593                                       const struct object_id *tree_oid,
1594                                       const char *object_name,
1595                                       int object_name_len)
1596 {
1597         struct object_id oid;
1598         unsigned mode;
1599
1600         if (!prefix)
1601                 prefix = "";
1602
1603         if (file_exists(filename))
1604                 die("Path '%s' exists on disk, but not in '%.*s'.",
1605                     filename, object_name_len, object_name);
1606         if (is_missing_file_error(errno)) {
1607                 char *fullname = xstrfmt("%s%s", prefix, filename);
1608
1609                 if (!get_tree_entry(tree_oid, fullname, &oid, &mode)) {
1610                         die("Path '%s' exists, but not '%s'.\n"
1611                             "Did you mean '%.*s:%s' aka '%.*s:./%s'?",
1612                             fullname,
1613                             filename,
1614                             object_name_len, object_name,
1615                             fullname,
1616                             object_name_len, object_name,
1617                             filename);
1618                 }
1619                 die("Path '%s' does not exist in '%.*s'",
1620                     filename, object_name_len, object_name);
1621         }
1622 }
1623
1624 /* Must be called only when :stage:filename doesn't exist. */
1625 static void diagnose_invalid_index_path(int stage,
1626                                         const char *prefix,
1627                                         const char *filename)
1628 {
1629         const struct cache_entry *ce;
1630         int pos;
1631         unsigned namelen = strlen(filename);
1632         struct strbuf fullname = STRBUF_INIT;
1633
1634         if (!prefix)
1635                 prefix = "";
1636
1637         /* Wrong stage number? */
1638         pos = cache_name_pos(filename, namelen);
1639         if (pos < 0)
1640                 pos = -pos - 1;
1641         if (pos < active_nr) {
1642                 ce = active_cache[pos];
1643                 if (ce_namelen(ce) == namelen &&
1644                     !memcmp(ce->name, filename, namelen))
1645                         die("Path '%s' is in the index, but not at stage %d.\n"
1646                             "Did you mean ':%d:%s'?",
1647                             filename, stage,
1648                             ce_stage(ce), filename);
1649         }
1650
1651         /* Confusion between relative and absolute filenames? */
1652         strbuf_addstr(&fullname, prefix);
1653         strbuf_addstr(&fullname, filename);
1654         pos = cache_name_pos(fullname.buf, fullname.len);
1655         if (pos < 0)
1656                 pos = -pos - 1;
1657         if (pos < active_nr) {
1658                 ce = active_cache[pos];
1659                 if (ce_namelen(ce) == fullname.len &&
1660                     !memcmp(ce->name, fullname.buf, fullname.len))
1661                         die("Path '%s' is in the index, but not '%s'.\n"
1662                             "Did you mean ':%d:%s' aka ':%d:./%s'?",
1663                             fullname.buf, filename,
1664                             ce_stage(ce), fullname.buf,
1665                             ce_stage(ce), filename);
1666         }
1667
1668         if (file_exists(filename))
1669                 die("Path '%s' exists on disk, but not in the index.", filename);
1670         if (is_missing_file_error(errno))
1671                 die("Path '%s' does not exist (neither on disk nor in the index).",
1672                     filename);
1673
1674         strbuf_release(&fullname);
1675 }
1676
1677
1678 static char *resolve_relative_path(const char *rel)
1679 {
1680         if (!starts_with(rel, "./") && !starts_with(rel, "../"))
1681                 return NULL;
1682
1683         if (!is_inside_work_tree())
1684                 die("relative path syntax can't be used outside working tree.");
1685
1686         /* die() inside prefix_path() if resolved path is outside worktree */
1687         return prefix_path(startup_info->prefix,
1688                            startup_info->prefix ? strlen(startup_info->prefix) : 0,
1689                            rel);
1690 }
1691
1692 static int get_oid_with_context_1(const char *name,
1693                                   unsigned flags,
1694                                   const char *prefix,
1695                                   struct object_id *oid,
1696                                   struct object_context *oc)
1697 {
1698         int ret, bracket_depth;
1699         int namelen = strlen(name);
1700         const char *cp;
1701         int only_to_die = flags & GET_OID_ONLY_TO_DIE;
1702
1703         if (only_to_die)
1704                 flags |= GET_OID_QUIETLY;
1705
1706         memset(oc, 0, sizeof(*oc));
1707         oc->mode = S_IFINVALID;
1708         strbuf_init(&oc->symlink_path, 0);
1709         ret = get_oid_1(name, namelen, oid, flags);
1710         if (!ret)
1711                 return ret;
1712         /*
1713          * sha1:path --> object name of path in ent sha1
1714          * :path -> object name of absolute path in index
1715          * :./path -> object name of path relative to cwd in index
1716          * :[0-3]:path -> object name of path in index at stage
1717          * :/foo -> recent commit matching foo
1718          */
1719         if (name[0] == ':') {
1720                 int stage = 0;
1721                 const struct cache_entry *ce;
1722                 char *new_path = NULL;
1723                 int pos;
1724                 if (!only_to_die && namelen > 2 && name[1] == '/') {
1725                         struct commit_list *list = NULL;
1726
1727                         for_each_ref(handle_one_ref, &list);
1728                         head_ref(handle_one_ref, &list);
1729                         commit_list_sort_by_date(&list);
1730                         return get_oid_oneline(name + 2, oid, list);
1731                 }
1732                 if (namelen < 3 ||
1733                     name[2] != ':' ||
1734                     name[1] < '0' || '3' < name[1])
1735                         cp = name + 1;
1736                 else {
1737                         stage = name[1] - '0';
1738                         cp = name + 3;
1739                 }
1740                 new_path = resolve_relative_path(cp);
1741                 if (!new_path) {
1742                         namelen = namelen - (cp - name);
1743                 } else {
1744                         cp = new_path;
1745                         namelen = strlen(cp);
1746                 }
1747
1748                 if (flags & GET_OID_RECORD_PATH)
1749                         oc->path = xstrdup(cp);
1750
1751                 if (!active_cache)
1752                         read_cache();
1753                 pos = cache_name_pos(cp, namelen);
1754                 if (pos < 0)
1755                         pos = -pos - 1;
1756                 while (pos < active_nr) {
1757                         ce = active_cache[pos];
1758                         if (ce_namelen(ce) != namelen ||
1759                             memcmp(ce->name, cp, namelen))
1760                                 break;
1761                         if (ce_stage(ce) == stage) {
1762                                 oidcpy(oid, &ce->oid);
1763                                 oc->mode = ce->ce_mode;
1764                                 free(new_path);
1765                                 return 0;
1766                         }
1767                         pos++;
1768                 }
1769                 if (only_to_die && name[1] && name[1] != '/')
1770                         diagnose_invalid_index_path(stage, prefix, cp);
1771                 free(new_path);
1772                 return -1;
1773         }
1774         for (cp = name, bracket_depth = 0; *cp; cp++) {
1775                 if (*cp == '{')
1776                         bracket_depth++;
1777                 else if (bracket_depth && *cp == '}')
1778                         bracket_depth--;
1779                 else if (!bracket_depth && *cp == ':')
1780                         break;
1781         }
1782         if (*cp == ':') {
1783                 struct object_id tree_oid;
1784                 int len = cp - name;
1785                 unsigned sub_flags = flags;
1786
1787                 sub_flags &= ~GET_OID_DISAMBIGUATORS;
1788                 sub_flags |= GET_OID_TREEISH;
1789
1790                 if (!get_oid_1(name, len, &tree_oid, sub_flags)) {
1791                         const char *filename = cp+1;
1792                         char *new_filename = NULL;
1793
1794                         new_filename = resolve_relative_path(filename);
1795                         if (new_filename)
1796                                 filename = new_filename;
1797                         if (flags & GET_OID_FOLLOW_SYMLINKS) {
1798                                 ret = get_tree_entry_follow_symlinks(&tree_oid,
1799                                         filename, oid, &oc->symlink_path,
1800                                         &oc->mode);
1801                         } else {
1802                                 ret = get_tree_entry(&tree_oid, filename, oid,
1803                                                      &oc->mode);
1804                                 if (ret && only_to_die) {
1805                                         diagnose_invalid_oid_path(prefix,
1806                                                                    filename,
1807                                                                    &tree_oid,
1808                                                                    name, len);
1809                                 }
1810                         }
1811                         if (flags & GET_OID_RECORD_PATH)
1812                                 oc->path = xstrdup(filename);
1813
1814                         free(new_filename);
1815                         return ret;
1816                 } else {
1817                         if (only_to_die)
1818                                 die("Invalid object name '%.*s'.", len, name);
1819                 }
1820         }
1821         return ret;
1822 }
1823
1824 /*
1825  * Call this function when you know "name" given by the end user must
1826  * name an object but it doesn't; the function _may_ die with a better
1827  * diagnostic message than "no such object 'name'", e.g. "Path 'doc' does not
1828  * exist in 'HEAD'" when given "HEAD:doc", or it may return in which case
1829  * you have a chance to diagnose the error further.
1830  */
1831 void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
1832 {
1833         struct object_context oc;
1834         struct object_id oid;
1835         get_oid_with_context_1(name, GET_OID_ONLY_TO_DIE, prefix, &oid, &oc);
1836 }
1837
1838 int get_oid_with_context(const char *str, unsigned flags, struct object_id *oid, struct object_context *oc)
1839 {
1840         if (flags & GET_OID_FOLLOW_SYMLINKS && flags & GET_OID_ONLY_TO_DIE)
1841                 BUG("incompatible flags for get_sha1_with_context");
1842         return get_oid_with_context_1(str, flags, NULL, oid, oc);
1843 }