770ea4fe805969b68fdbc65fed769cc5202440ff
   1#include "cache.h"
   2#include "tag.h"
   3#include "commit.h"
   4#include "tree.h"
   5#include "blob.h"
   6#include "tree-walk.h"
   7#include "refs.h"
   8#include "remote.h"
   9#include "dir.h"
  10
  11static int get_sha1_oneline(const char *, unsigned char *, struct commit_list *);
  12
  13typedef int (*disambiguate_hint_fn)(const unsigned char *, void *);
  14
  15struct disambiguate_state {
  16        disambiguate_hint_fn fn;
  17        void *cb_data;
  18        unsigned char candidate[20];
  19        unsigned candidate_exists:1;
  20        unsigned candidate_checked:1;
  21        unsigned candidate_ok:1;
  22        unsigned disambiguate_fn_used:1;
  23        unsigned ambiguous:1;
  24        unsigned always_call_fn:1;
  25};
  26
  27static void update_candidates(struct disambiguate_state *ds, const unsigned char *current)
  28{
  29        if (ds->always_call_fn) {
  30                ds->ambiguous = ds->fn(current, ds->cb_data) ? 1 : 0;
  31                return;
  32        }
  33        if (!ds->candidate_exists) {
  34                /* this is the first candidate */
  35                hashcpy(ds->candidate, current);
  36                ds->candidate_exists = 1;
  37                return;
  38        } else if (!hashcmp(ds->candidate, current)) {
  39                /* the same as what we already have seen */
  40                return;
  41        }
  42
  43        if (!ds->fn) {
  44                /* cannot disambiguate between ds->candidate and current */
  45                ds->ambiguous = 1;
  46                return;
  47        }
  48
  49        if (!ds->candidate_checked) {
  50                ds->candidate_ok = ds->fn(ds->candidate, ds->cb_data);
  51                ds->disambiguate_fn_used = 1;
  52                ds->candidate_checked = 1;
  53        }
  54
  55        if (!ds->candidate_ok) {
  56                /* discard the candidate; we know it does not satisfy fn */
  57                hashcpy(ds->candidate, current);
  58                ds->candidate_checked = 0;
  59                return;
  60        }
  61
  62        /* if we reach this point, we know ds->candidate satisfies fn */
  63        if (ds->fn(current, ds->cb_data)) {
  64                /*
  65                 * if both current and candidate satisfy fn, we cannot
  66                 * disambiguate.
  67                 */
  68                ds->candidate_ok = 0;
  69                ds->ambiguous = 1;
  70        }
  71
  72        /* otherwise, current can be discarded and candidate is still good */
  73}
  74
  75static void find_short_object_filename(int len, const char *hex_pfx, struct disambiguate_state *ds)
  76{
  77        struct alternate_object_database *alt;
  78        char hex[40];
  79        static struct alternate_object_database *fakeent;
  80
  81        if (!fakeent) {
  82                /*
  83                 * Create a "fake" alternate object database that
  84                 * points to our own object database, to make it
  85                 * easier to get a temporary working space in
  86                 * alt->name/alt->base while iterating over the
  87                 * object databases including our own.
  88                 */
  89                fakeent = alloc_alt_odb(get_object_directory());
  90        }
  91        fakeent->next = alt_odb_list;
  92
  93        xsnprintf(hex, sizeof(hex), "%.2s", hex_pfx);
  94        for (alt = fakeent; alt && !ds->ambiguous; alt = alt->next) {
  95                struct dirent *de;
  96                DIR *dir;
  97
  98                /*
  99                 * every alt_odb struct has 42 extra bytes after the base
 100                 * for exactly this purpose
 101                 */
 102                xsnprintf(alt->name, 42, "%.2s/", hex_pfx);
 103                dir = opendir(alt->scratch);
 104                if (!dir)
 105                        continue;
 106
 107                while (!ds->ambiguous && (de = readdir(dir)) != NULL) {
 108                        unsigned char sha1[20];
 109
 110                        if (strlen(de->d_name) != 38)
 111                                continue;
 112                        if (memcmp(de->d_name, hex_pfx + 2, len - 2))
 113                                continue;
 114                        memcpy(hex + 2, de->d_name, 38);
 115                        if (!get_sha1_hex(hex, sha1))
 116                                update_candidates(ds, sha1);
 117                }
 118                closedir(dir);
 119        }
 120}
 121
 122static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
 123{
 124        do {
 125                if (*a != *b)
 126                        return 0;
 127                a++;
 128                b++;
 129                len -= 2;
 130        } while (len > 1);
 131        if (len)
 132                if ((*a ^ *b) & 0xf0)
 133                        return 0;
 134        return 1;
 135}
 136
 137static void unique_in_pack(int len,
 138                          const unsigned char *bin_pfx,
 139                           struct packed_git *p,
 140                           struct disambiguate_state *ds)
 141{
 142        uint32_t num, last, i, first = 0;
 143        const unsigned char *current = NULL;
 144
 145        open_pack_index(p);
 146        num = p->num_objects;
 147        last = num;
 148        while (first < last) {
 149                uint32_t mid = (first + last) / 2;
 150                const unsigned char *current;
 151                int cmp;
 152
 153                current = nth_packed_object_sha1(p, mid);
 154                cmp = hashcmp(bin_pfx, current);
 155                if (!cmp) {
 156                        first = mid;
 157                        break;
 158                }
 159                if (cmp > 0) {
 160                        first = mid+1;
 161                        continue;
 162                }
 163                last = mid;
 164        }
 165
 166        /*
 167         * At this point, "first" is the location of the lowest object
 168         * with an object name that could match "bin_pfx".  See if we have
 169         * 0, 1 or more objects that actually match(es).
 170         */
 171        for (i = first; i < num && !ds->ambiguous; i++) {
 172                current = nth_packed_object_sha1(p, i);
 173                if (!match_sha(len, bin_pfx, current))
 174                        break;
 175                update_candidates(ds, current);
 176        }
 177}
 178
 179static void find_short_packed_object(int len, const unsigned char *bin_pfx,
 180                                     struct disambiguate_state *ds)
 181{
 182        struct packed_git *p;
 183
 184        prepare_packed_git();
 185        for (p = packed_git; p && !ds->ambiguous; p = p->next)
 186                unique_in_pack(len, bin_pfx, p, ds);
 187}
 188
 189#define SHORT_NAME_NOT_FOUND (-1)
 190#define SHORT_NAME_AMBIGUOUS (-2)
 191
 192static int finish_object_disambiguation(struct disambiguate_state *ds,
 193                                        unsigned char *sha1)
 194{
 195        if (ds->ambiguous)
 196                return SHORT_NAME_AMBIGUOUS;
 197
 198        if (!ds->candidate_exists)
 199                return SHORT_NAME_NOT_FOUND;
 200
 201        if (!ds->candidate_checked)
 202                /*
 203                 * If this is the only candidate, there is no point
 204                 * calling the disambiguation hint callback.
 205                 *
 206                 * On the other hand, if the current candidate
 207                 * replaced an earlier candidate that did _not_ pass
 208                 * the disambiguation hint callback, then we do have
 209                 * more than one objects that match the short name
 210                 * given, so we should make sure this one matches;
 211                 * otherwise, if we discovered this one and the one
 212                 * that we previously discarded in the reverse order,
 213                 * we would end up showing different results in the
 214                 * same repository!
 215                 */
 216                ds->candidate_ok = (!ds->disambiguate_fn_used ||
 217                                    ds->fn(ds->candidate, ds->cb_data));
 218
 219        if (!ds->candidate_ok)
 220                return SHORT_NAME_AMBIGUOUS;
 221
 222        hashcpy(sha1, ds->candidate);
 223        return 0;
 224}
 225
 226static int disambiguate_commit_only(const unsigned char *sha1, void *cb_data_unused)
 227{
 228        int kind = sha1_object_info(sha1, NULL);
 229        return kind == OBJ_COMMIT;
 230}
 231
 232static int disambiguate_committish_only(const unsigned char *sha1, void *cb_data_unused)
 233{
 234        struct object *obj;
 235        int kind;
 236
 237        kind = sha1_object_info(sha1, NULL);
 238        if (kind == OBJ_COMMIT)
 239                return 1;
 240        if (kind != OBJ_TAG)
 241                return 0;
 242
 243        /* We need to do this the hard way... */
 244        obj = deref_tag(parse_object(sha1), NULL, 0);
 245        if (obj && obj->type == OBJ_COMMIT)
 246                return 1;
 247        return 0;
 248}
 249
 250static int disambiguate_tree_only(const unsigned char *sha1, void *cb_data_unused)
 251{
 252        int kind = sha1_object_info(sha1, NULL);
 253        return kind == OBJ_TREE;
 254}
 255
 256static int disambiguate_treeish_only(const unsigned char *sha1, void *cb_data_unused)
 257{
 258        struct object *obj;
 259        int kind;
 260
 261        kind = sha1_object_info(sha1, NULL);
 262        if (kind == OBJ_TREE || kind == OBJ_COMMIT)
 263                return 1;
 264        if (kind != OBJ_TAG)
 265                return 0;
 266
 267        /* We need to do this the hard way... */
 268        obj = deref_tag(lookup_object(sha1), NULL, 0);
 269        if (obj && (obj->type == OBJ_TREE || obj->type == OBJ_COMMIT))
 270                return 1;
 271        return 0;
 272}
 273
 274static int disambiguate_blob_only(const unsigned char *sha1, void *cb_data_unused)
 275{
 276        int kind = sha1_object_info(sha1, NULL);
 277        return kind == OBJ_BLOB;
 278}
 279
 280static int prepare_prefixes(const char *name, int len,
 281                            unsigned char *bin_pfx,
 282                            char *hex_pfx)
 283{
 284        int i;
 285
 286        hashclr(bin_pfx);
 287        memset(hex_pfx, 'x', 40);
 288        for (i = 0; i < len ;i++) {
 289                unsigned char c = name[i];
 290                unsigned char val;
 291                if (c >= '0' && c <= '9')
 292                        val = c - '0';
 293                else if (c >= 'a' && c <= 'f')
 294                        val = c - 'a' + 10;
 295                else if (c >= 'A' && c <='F') {
 296                        val = c - 'A' + 10;
 297                        c -= 'A' - 'a';
 298                }
 299                else
 300                        return -1;
 301                hex_pfx[i] = c;
 302                if (!(i & 1))
 303                        val <<= 4;
 304                bin_pfx[i >> 1] |= val;
 305        }
 306        return 0;
 307}
 308
 309static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 310                          unsigned flags)
 311{
 312        int status;
 313        char hex_pfx[40];
 314        unsigned char bin_pfx[20];
 315        struct disambiguate_state ds;
 316        int quietly = !!(flags & GET_SHA1_QUIETLY);
 317
 318        if (len < MINIMUM_ABBREV || len > 40)
 319                return -1;
 320        if (prepare_prefixes(name, len, bin_pfx, hex_pfx) < 0)
 321                return -1;
 322
 323        prepare_alt_odb();
 324
 325        memset(&ds, 0, sizeof(ds));
 326        if (flags & GET_SHA1_COMMIT)
 327                ds.fn = disambiguate_commit_only;
 328        else if (flags & GET_SHA1_COMMITTISH)
 329                ds.fn = disambiguate_committish_only;
 330        else if (flags & GET_SHA1_TREE)
 331                ds.fn = disambiguate_tree_only;
 332        else if (flags & GET_SHA1_TREEISH)
 333                ds.fn = disambiguate_treeish_only;
 334        else if (flags & GET_SHA1_BLOB)
 335                ds.fn = disambiguate_blob_only;
 336
 337        find_short_object_filename(len, hex_pfx, &ds);
 338        find_short_packed_object(len, bin_pfx, &ds);
 339        status = finish_object_disambiguation(&ds, sha1);
 340
 341        if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
 342                return error("short SHA1 %.*s is ambiguous.", len, hex_pfx);
 343        return status;
 344}
 345
 346int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
 347{
 348        char hex_pfx[40];
 349        unsigned char bin_pfx[20];
 350        struct disambiguate_state ds;
 351        int len = strlen(prefix);
 352
 353        if (len < MINIMUM_ABBREV || len > 40)
 354                return -1;
 355        if (prepare_prefixes(prefix, len, bin_pfx, hex_pfx) < 0)
 356                return -1;
 357
 358        prepare_alt_odb();
 359
 360        memset(&ds, 0, sizeof(ds));
 361        ds.always_call_fn = 1;
 362        ds.cb_data = cb_data;
 363        ds.fn = fn;
 364
 365        find_short_object_filename(len, hex_pfx, &ds);
 366        find_short_packed_object(len, bin_pfx, &ds);
 367        return ds.ambiguous;
 368}
 369
 370int find_unique_abbrev_r(char *hex, const unsigned char *sha1, int len)
 371{
 372        int status, exists;
 373
 374        sha1_to_hex_r(hex, sha1);
 375        if (len == 40 || !len)
 376                return 40;
 377        exists = has_sha1_file(sha1);
 378        while (len < 40) {
 379                unsigned char sha1_ret[20];
 380                status = get_short_sha1(hex, len, sha1_ret, GET_SHA1_QUIETLY);
 381                if (exists
 382                    ? !status
 383                    : status == SHORT_NAME_NOT_FOUND) {
 384                        hex[len] = 0;
 385                        return len;
 386                }
 387                len++;
 388        }
 389        return len;
 390}
 391
 392const char *find_unique_abbrev(const unsigned char *sha1, int len)
 393{
 394        static char hex[GIT_SHA1_HEXSZ + 1];
 395        find_unique_abbrev_r(hex, sha1, len);
 396        return hex;
 397}
 398
 399static int ambiguous_path(const char *path, int len)
 400{
 401        int slash = 1;
 402        int cnt;
 403
 404        for (cnt = 0; cnt < len; cnt++) {
 405                switch (*path++) {
 406                case '\0':
 407                        break;
 408                case '/':
 409                        if (slash)
 410                                break;
 411                        slash = 1;
 412                        continue;
 413                case '.':
 414                        continue;
 415                default:
 416                        slash = 0;
 417                        continue;
 418                }
 419                break;
 420        }
 421        return slash;
 422}
 423
 424static inline int at_mark(const char *string, int len,
 425                          const char **suffix, int nr)
 426{
 427        int i;
 428
 429        for (i = 0; i < nr; i++) {
 430                int suffix_len = strlen(suffix[i]);
 431                if (suffix_len <= len
 432                    && !memcmp(string, suffix[i], suffix_len))
 433                        return suffix_len;
 434        }
 435        return 0;
 436}
 437
 438static inline int upstream_mark(const char *string, int len)
 439{
 440        const char *suffix[] = { "@{upstream}", "@{u}" };
 441        return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
 442}
 443
 444static inline int push_mark(const char *string, int len)
 445{
 446        const char *suffix[] = { "@{push}" };
 447        return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
 448}
 449
 450static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags);
 451static int interpret_nth_prior_checkout(const char *name, int namelen, struct strbuf *buf);
 452
 453static int get_sha1_basic(const char *str, int len, unsigned char *sha1,
 454                          unsigned int flags)
 455{
 456        static const char *warn_msg = "refname '%.*s' is ambiguous.";
 457        static const char *object_name_msg = N_(
 458        "Git normally never creates a ref that ends with 40 hex characters\n"
 459        "because it will be ignored when you just specify 40-hex. These refs\n"
 460        "may be created by mistake. For example,\n"
 461        "\n"
 462        "  git checkout -b $br $(git rev-parse ...)\n"
 463        "\n"
 464        "where \"$br\" is somehow empty and a 40-hex ref is created. Please\n"
 465        "examine these refs and maybe delete them. Turn this message off by\n"
 466        "running \"git config advice.objectNameWarning false\"");
 467        unsigned char tmp_sha1[20];
 468        char *real_ref = NULL;
 469        int refs_found = 0;
 470        int at, reflog_len, nth_prior = 0;
 471
 472        if (len == 40 && !get_sha1_hex(str, sha1)) {
 473                if (warn_ambiguous_refs && warn_on_object_refname_ambiguity) {
 474                        refs_found = dwim_ref(str, len, tmp_sha1, &real_ref);
 475                        if (refs_found > 0) {
 476                                warning(warn_msg, len, str);
 477                                if (advice_object_name_warning)
 478                                        fprintf(stderr, "%s\n", _(object_name_msg));
 479                        }
 480                        free(real_ref);
 481                }
 482                return 0;
 483        }
 484
 485        /* basic@{time or number or -number} format to query ref-log */
 486        reflog_len = at = 0;
 487        if (len && str[len-1] == '}') {
 488                for (at = len-4; at >= 0; at--) {
 489                        if (str[at] == '@' && str[at+1] == '{') {
 490                                if (str[at+2] == '-') {
 491                                        if (at != 0)
 492                                                /* @{-N} not at start */
 493                                                return -1;
 494                                        nth_prior = 1;
 495                                        continue;
 496                                }
 497                                if (!upstream_mark(str + at, len - at) &&
 498                                    !push_mark(str + at, len - at)) {
 499                                        reflog_len = (len-1) - (at+2);
 500                                        len = at;
 501                                }
 502                                break;
 503                        }
 504                }
 505        }
 506
 507        /* Accept only unambiguous ref paths. */
 508        if (len && ambiguous_path(str, len))
 509                return -1;
 510
 511        if (nth_prior) {
 512                struct strbuf buf = STRBUF_INIT;
 513                int detached;
 514
 515                if (interpret_nth_prior_checkout(str, len, &buf) > 0) {
 516                        detached = (buf.len == 40 && !get_sha1_hex(buf.buf, sha1));
 517                        strbuf_release(&buf);
 518                        if (detached)
 519                                return 0;
 520                }
 521        }
 522
 523        if (!len && reflog_len)
 524                /* allow "@{...}" to mean the current branch reflog */
 525                refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
 526        else if (reflog_len)
 527                refs_found = dwim_log(str, len, sha1, &real_ref);
 528        else
 529                refs_found = dwim_ref(str, len, sha1, &real_ref);
 530
 531        if (!refs_found)
 532                return -1;
 533
 534        if (warn_ambiguous_refs && !(flags & GET_SHA1_QUIETLY) &&
 535            (refs_found > 1 ||
 536             !get_short_sha1(str, len, tmp_sha1, GET_SHA1_QUIETLY)))
 537                warning(warn_msg, len, str);
 538
 539        if (reflog_len) {
 540                int nth, i;
 541                unsigned long at_time;
 542                unsigned long co_time;
 543                int co_tz, co_cnt;
 544
 545                /* Is it asking for N-th entry, or approxidate? */
 546                for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 547                        char ch = str[at+2+i];
 548                        if ('0' <= ch && ch <= '9')
 549                                nth = nth * 10 + ch - '0';
 550                        else
 551                                nth = -1;
 552                }
 553                if (100000000 <= nth) {
 554                        at_time = nth;
 555                        nth = -1;
 556                } else if (0 <= nth)
 557                        at_time = 0;
 558                else {
 559                        int errors = 0;
 560                        char *tmp = xstrndup(str + at + 2, reflog_len);
 561                        at_time = approxidate_careful(tmp, &errors);
 562                        free(tmp);
 563                        if (errors) {
 564                                free(real_ref);
 565                                return -1;
 566                        }
 567                }
 568                if (read_ref_at(real_ref, flags, at_time, nth, sha1, NULL,
 569                                &co_time, &co_tz, &co_cnt)) {
 570                        if (!len) {
 571                                if (starts_with(real_ref, "refs/heads/")) {
 572                                        str = real_ref + 11;
 573                                        len = strlen(real_ref + 11);
 574                                } else {
 575                                        /* detached HEAD */
 576                                        str = "HEAD";
 577                                        len = 4;
 578                                }
 579                        }
 580                        if (at_time) {
 581                                if (!(flags & GET_SHA1_QUIETLY)) {
 582                                        warning("Log for '%.*s' only goes "
 583                                                "back to %s.", len, str,
 584                                                show_date(co_time, co_tz, DATE_MODE(RFC2822)));
 585                                }
 586                        } else {
 587                                if (flags & GET_SHA1_QUIETLY) {
 588                                        exit(128);
 589                                }
 590                                die("Log for '%.*s' only has %d entries.",
 591                                    len, str, co_cnt);
 592                        }
 593                }
 594        }
 595
 596        free(real_ref);
 597        return 0;
 598}
 599
 600static int get_parent(const char *name, int len,
 601                      unsigned char *result, int idx)
 602{
 603        unsigned char sha1[20];
 604        int ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 605        struct commit *commit;
 606        struct commit_list *p;
 607
 608        if (ret)
 609                return ret;
 610        commit = lookup_commit_reference(sha1);
 611        if (parse_commit(commit))
 612                return -1;
 613        if (!idx) {
 614                hashcpy(result, commit->object.oid.hash);
 615                return 0;
 616        }
 617        p = commit->parents;
 618        while (p) {
 619                if (!--idx) {
 620                        hashcpy(result, p->item->object.oid.hash);
 621                        return 0;
 622                }
 623                p = p->next;
 624        }
 625        return -1;
 626}
 627
 628static int get_nth_ancestor(const char *name, int len,
 629                            unsigned char *result, int generation)
 630{
 631        unsigned char sha1[20];
 632        struct commit *commit;
 633        int ret;
 634
 635        ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 636        if (ret)
 637                return ret;
 638        commit = lookup_commit_reference(sha1);
 639        if (!commit)
 640                return -1;
 641
 642        while (generation--) {
 643                if (parse_commit(commit) || !commit->parents)
 644                        return -1;
 645                commit = commit->parents->item;
 646        }
 647        hashcpy(result, commit->object.oid.hash);
 648        return 0;
 649}
 650
 651struct object *peel_to_type(const char *name, int namelen,
 652                            struct object *o, enum object_type expected_type)
 653{
 654        if (name && !namelen)
 655                namelen = strlen(name);
 656        while (1) {
 657                if (!o || (!o->parsed && !parse_object(o->oid.hash)))
 658                        return NULL;
 659                if (expected_type == OBJ_ANY || o->type == expected_type)
 660                        return o;
 661                if (o->type == OBJ_TAG)
 662                        o = ((struct tag*) o)->tagged;
 663                else if (o->type == OBJ_COMMIT)
 664                        o = &(((struct commit *) o)->tree->object);
 665                else {
 666                        if (name)
 667                                error("%.*s: expected %s type, but the object "
 668                                      "dereferences to %s type",
 669                                      namelen, name, typename(expected_type),
 670                                      typename(o->type));
 671                        return NULL;
 672                }
 673        }
 674}
 675
 676static int peel_onion(const char *name, int len, unsigned char *sha1)
 677{
 678        unsigned char outer[20];
 679        const char *sp;
 680        unsigned int expected_type = 0;
 681        unsigned lookup_flags = 0;
 682        struct object *o;
 683
 684        /*
 685         * "ref^{type}" dereferences ref repeatedly until you cannot
 686         * dereference anymore, or you get an object of given type,
 687         * whichever comes first.  "ref^{}" means just dereference
 688         * tags until you get a non-tag.  "ref^0" is a shorthand for
 689         * "ref^{commit}".  "commit^{tree}" could be used to find the
 690         * top-level tree of the given commit.
 691         */
 692        if (len < 4 || name[len-1] != '}')
 693                return -1;
 694
 695        for (sp = name + len - 1; name <= sp; sp--) {
 696                int ch = *sp;
 697                if (ch == '{' && name < sp && sp[-1] == '^')
 698                        break;
 699        }
 700        if (sp <= name)
 701                return -1;
 702
 703        sp++; /* beginning of type name, or closing brace for empty */
 704        if (starts_with(sp, "commit}"))
 705                expected_type = OBJ_COMMIT;
 706        else if (starts_with(sp, "tag}"))
 707                expected_type = OBJ_TAG;
 708        else if (starts_with(sp, "tree}"))
 709                expected_type = OBJ_TREE;
 710        else if (starts_with(sp, "blob}"))
 711                expected_type = OBJ_BLOB;
 712        else if (starts_with(sp, "object}"))
 713                expected_type = OBJ_ANY;
 714        else if (sp[0] == '}')
 715                expected_type = OBJ_NONE;
 716        else if (sp[0] == '/')
 717                expected_type = OBJ_COMMIT;
 718        else
 719                return -1;
 720
 721        if (expected_type == OBJ_COMMIT)
 722                lookup_flags = GET_SHA1_COMMITTISH;
 723        else if (expected_type == OBJ_TREE)
 724                lookup_flags = GET_SHA1_TREEISH;
 725
 726        if (get_sha1_1(name, sp - name - 2, outer, lookup_flags))
 727                return -1;
 728
 729        o = parse_object(outer);
 730        if (!o)
 731                return -1;
 732        if (!expected_type) {
 733                o = deref_tag(o, name, sp - name - 2);
 734                if (!o || (!o->parsed && !parse_object(o->oid.hash)))
 735                        return -1;
 736                hashcpy(sha1, o->oid.hash);
 737                return 0;
 738        }
 739
 740        /*
 741         * At this point, the syntax look correct, so
 742         * if we do not get the needed object, we should
 743         * barf.
 744         */
 745        o = peel_to_type(name, len, o, expected_type);
 746        if (!o)
 747                return -1;
 748
 749        hashcpy(sha1, o->oid.hash);
 750        if (sp[0] == '/') {
 751                /* "$commit^{/foo}" */
 752                char *prefix;
 753                int ret;
 754                struct commit_list *list = NULL;
 755
 756                /*
 757                 * $commit^{/}. Some regex implementation may reject.
 758                 * We don't need regex anyway. '' pattern always matches.
 759                 */
 760                if (sp[1] == '}')
 761                        return 0;
 762
 763                prefix = xstrndup(sp + 1, name + len - 1 - (sp + 1));
 764                commit_list_insert((struct commit *)o, &list);
 765                ret = get_sha1_oneline(prefix, sha1, list);
 766                free(prefix);
 767                return ret;
 768        }
 769        return 0;
 770}
 771
 772static int get_describe_name(const char *name, int len, unsigned char *sha1)
 773{
 774        const char *cp;
 775        unsigned flags = GET_SHA1_QUIETLY | GET_SHA1_COMMIT;
 776
 777        for (cp = name + len - 1; name + 2 <= cp; cp--) {
 778                char ch = *cp;
 779                if (!isxdigit(ch)) {
 780                        /* We must be looking at g in "SOMETHING-g"
 781                         * for it to be describe output.
 782                         */
 783                        if (ch == 'g' && cp[-1] == '-') {
 784                                cp++;
 785                                len -= cp - name;
 786                                return get_short_sha1(cp, len, sha1, flags);
 787                        }
 788                }
 789        }
 790        return -1;
 791}
 792
 793static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags)
 794{
 795        int ret, has_suffix;
 796        const char *cp;
 797
 798        /*
 799         * "name~3" is "name^^^", "name~" is "name~1", and "name^" is "name^1".
 800         */
 801        has_suffix = 0;
 802        for (cp = name + len - 1; name <= cp; cp--) {
 803                int ch = *cp;
 804                if ('0' <= ch && ch <= '9')
 805                        continue;
 806                if (ch == '~' || ch == '^')
 807                        has_suffix = ch;
 808                break;
 809        }
 810
 811        if (has_suffix) {
 812                int num = 0;
 813                int len1 = cp - name;
 814                cp++;
 815                while (cp < name + len)
 816                        num = num * 10 + *cp++ - '0';
 817                if (!num && len1 == len - 1)
 818                        num = 1;
 819                if (has_suffix == '^')
 820                        return get_parent(name, len1, sha1, num);
 821                /* else if (has_suffix == '~') -- goes without saying */
 822                return get_nth_ancestor(name, len1, sha1, num);
 823        }
 824
 825        ret = peel_onion(name, len, sha1);
 826        if (!ret)
 827                return 0;
 828
 829        ret = get_sha1_basic(name, len, sha1, lookup_flags);
 830        if (!ret)
 831                return 0;
 832
 833        /* It could be describe output that is "SOMETHING-gXXXX" */
 834        ret = get_describe_name(name, len, sha1);
 835        if (!ret)
 836                return 0;
 837
 838        return get_short_sha1(name, len, sha1, lookup_flags);
 839}
 840
 841/*
 842 * This interprets names like ':/Initial revision of "git"' by searching
 843 * through history and returning the first commit whose message starts
 844 * the given regular expression.
 845 *
 846 * For negative-matching, prefix the pattern-part with '!-', like: ':/!-WIP'.
 847 *
 848 * For a literal '!' character at the beginning of a pattern, you have to repeat
 849 * that, like: ':/!!foo'
 850 *
 851 * For future extension, all other sequences beginning with ':/!' are reserved.
 852 */
 853
 854/* Remember to update object flag allocation in object.h */
 855#define ONELINE_SEEN (1u<<20)
 856
 857static int handle_one_ref(const char *path, const struct object_id *oid,
 858                          int flag, void *cb_data)
 859{
 860        struct commit_list **list = cb_data;
 861        struct object *object = parse_object(oid->hash);
 862        if (!object)
 863                return 0;
 864        if (object->type == OBJ_TAG) {
 865                object = deref_tag(object, path, strlen(path));
 866                if (!object)
 867                        return 0;
 868        }
 869        if (object->type != OBJ_COMMIT)
 870                return 0;
 871        commit_list_insert((struct commit *)object, list);
 872        return 0;
 873}
 874
 875static int get_sha1_oneline(const char *prefix, unsigned char *sha1,
 876                            struct commit_list *list)
 877{
 878        struct commit_list *backup = NULL, *l;
 879        int found = 0;
 880        int negative = 0;
 881        regex_t regex;
 882
 883        if (prefix[0] == '!') {
 884                prefix++;
 885
 886                if (prefix[0] == '-') {
 887                        prefix++;
 888                        negative = 1;
 889                } else if (prefix[0] != '!') {
 890                        return -1;
 891                }
 892        }
 893
 894        if (regcomp(&regex, prefix, REG_EXTENDED))
 895                return -1;
 896
 897        for (l = list; l; l = l->next) {
 898                l->item->object.flags |= ONELINE_SEEN;
 899                commit_list_insert(l->item, &backup);
 900        }
 901        while (list) {
 902                const char *p, *buf;
 903                struct commit *commit;
 904                int matches;
 905
 906                commit = pop_most_recent_commit(&list, ONELINE_SEEN);
 907                if (!parse_object(commit->object.oid.hash))
 908                        continue;
 909                buf = get_commit_buffer(commit, NULL);
 910                p = strstr(buf, "\n\n");
 911                matches = negative ^ (p && !regexec(&regex, p + 2, 0, NULL, 0));
 912                unuse_commit_buffer(commit, buf);
 913
 914                if (matches) {
 915                        hashcpy(sha1, commit->object.oid.hash);
 916                        found = 1;
 917                        break;
 918                }
 919        }
 920        regfree(&regex);
 921        free_commit_list(list);
 922        for (l = backup; l; l = l->next)
 923                clear_commit_marks(l->item, ONELINE_SEEN);
 924        free_commit_list(backup);
 925        return found ? 0 : -1;
 926}
 927
 928struct grab_nth_branch_switch_cbdata {
 929        int remaining;
 930        struct strbuf buf;
 931};
 932
 933static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
 934                                  const char *email, unsigned long timestamp, int tz,
 935                                  const char *message, void *cb_data)
 936{
 937        struct grab_nth_branch_switch_cbdata *cb = cb_data;
 938        const char *match = NULL, *target = NULL;
 939        size_t len;
 940
 941        if (skip_prefix(message, "checkout: moving from ", &match))
 942                target = strstr(match, " to ");
 943
 944        if (!match || !target)
 945                return 0;
 946        if (--(cb->remaining) == 0) {
 947                len = target - match;
 948                strbuf_reset(&cb->buf);
 949                strbuf_add(&cb->buf, match, len);
 950                return 1; /* we are done */
 951        }
 952        return 0;
 953}
 954
 955/*
 956 * Parse @{-N} syntax, return the number of characters parsed
 957 * if successful; otherwise signal an error with negative value.
 958 */
 959static int interpret_nth_prior_checkout(const char *name, int namelen,
 960                                        struct strbuf *buf)
 961{
 962        long nth;
 963        int retval;
 964        struct grab_nth_branch_switch_cbdata cb;
 965        const char *brace;
 966        char *num_end;
 967
 968        if (namelen < 4)
 969                return -1;
 970        if (name[0] != '@' || name[1] != '{' || name[2] != '-')
 971                return -1;
 972        brace = memchr(name, '}', namelen);
 973        if (!brace)
 974                return -1;
 975        nth = strtol(name + 3, &num_end, 10);
 976        if (num_end != brace)
 977                return -1;
 978        if (nth <= 0)
 979                return -1;
 980        cb.remaining = nth;
 981        strbuf_init(&cb.buf, 20);
 982
 983        retval = 0;
 984        if (0 < for_each_reflog_ent_reverse("HEAD", grab_nth_branch_switch, &cb)) {
 985                strbuf_reset(buf);
 986                strbuf_addbuf(buf, &cb.buf);
 987                retval = brace - name + 1;
 988        }
 989
 990        strbuf_release(&cb.buf);
 991        return retval;
 992}
 993
 994int get_oid_mb(const char *name, struct object_id *oid)
 995{
 996        struct commit *one, *two;
 997        struct commit_list *mbs;
 998        struct object_id oid_tmp;
 999        const char *dots;
1000        int st;
1001
1002        dots = strstr(name, "...");
1003        if (!dots)
1004                return get_oid(name, oid);
1005        if (dots == name)
1006                st = get_oid("HEAD", &oid_tmp);
1007        else {
1008                struct strbuf sb;
1009                strbuf_init(&sb, dots - name);
1010                strbuf_add(&sb, name, dots - name);
1011                st = get_sha1_committish(sb.buf, oid_tmp.hash);
1012                strbuf_release(&sb);
1013        }
1014        if (st)
1015                return st;
1016        one = lookup_commit_reference_gently(oid_tmp.hash, 0);
1017        if (!one)
1018                return -1;
1019
1020        if (get_sha1_committish(dots[3] ? (dots + 3) : "HEAD", oid_tmp.hash))
1021                return -1;
1022        two = lookup_commit_reference_gently(oid_tmp.hash, 0);
1023        if (!two)
1024                return -1;
1025        mbs = get_merge_bases(one, two);
1026        if (!mbs || mbs->next)
1027                st = -1;
1028        else {
1029                st = 0;
1030                oidcpy(oid, &mbs->item->object.oid);
1031        }
1032        free_commit_list(mbs);
1033        return st;
1034}
1035
1036/* parse @something syntax, when 'something' is not {.*} */
1037static int interpret_empty_at(const char *name, int namelen, int len, struct strbuf *buf)
1038{
1039        const char *next;
1040
1041        if (len || name[1] == '{')
1042                return -1;
1043
1044        /* make sure it's a single @, or @@{.*}, not @foo */
1045        next = memchr(name + len + 1, '@', namelen - len - 1);
1046        if (next && next[1] != '{')
1047                return -1;
1048        if (!next)
1049                next = name + namelen;
1050        if (next != name + 1)
1051                return -1;
1052
1053        strbuf_reset(buf);
1054        strbuf_add(buf, "HEAD", 4);
1055        return 1;
1056}
1057
1058static int reinterpret(const char *name, int namelen, int len, struct strbuf *buf)
1059{
1060        /* we have extra data, which might need further processing */
1061        struct strbuf tmp = STRBUF_INIT;
1062        int used = buf->len;
1063        int ret;
1064
1065        strbuf_add(buf, name + len, namelen - len);
1066        ret = interpret_branch_name(buf->buf, buf->len, &tmp);
1067        /* that data was not interpreted, remove our cruft */
1068        if (ret < 0) {
1069                strbuf_setlen(buf, used);
1070                return len;
1071        }
1072        strbuf_reset(buf);
1073        strbuf_addbuf(buf, &tmp);
1074        strbuf_release(&tmp);
1075        /* tweak for size of {-N} versus expanded ref name */
1076        return ret - used + len;
1077}
1078
1079static void set_shortened_ref(struct strbuf *buf, const char *ref)
1080{
1081        char *s = shorten_unambiguous_ref(ref, 0);
1082        strbuf_reset(buf);
1083        strbuf_addstr(buf, s);
1084        free(s);
1085}
1086
1087static int interpret_branch_mark(const char *name, int namelen,
1088                                 int at, struct strbuf *buf,
1089                                 int (*get_mark)(const char *, int),
1090                                 const char *(*get_data)(struct branch *,
1091                                                         struct strbuf *))
1092{
1093        int len;
1094        struct branch *branch;
1095        struct strbuf err = STRBUF_INIT;
1096        const char *value;
1097
1098        len = get_mark(name + at, namelen - at);
1099        if (!len)
1100                return -1;
1101
1102        if (memchr(name, ':', at))
1103                return -1;
1104
1105        if (at) {
1106                char *name_str = xmemdupz(name, at);
1107                branch = branch_get(name_str);
1108                free(name_str);
1109        } else
1110                branch = branch_get(NULL);
1111
1112        value = get_data(branch, &err);
1113        if (!value)
1114                die("%s", err.buf);
1115
1116        set_shortened_ref(buf, value);
1117        return len + at;
1118}
1119
1120/*
1121 * This reads short-hand syntax that not only evaluates to a commit
1122 * object name, but also can act as if the end user spelled the name
1123 * of the branch from the command line.
1124 *
1125 * - "@{-N}" finds the name of the Nth previous branch we were on, and
1126 *   places the name of the branch in the given buf and returns the
1127 *   number of characters parsed if successful.
1128 *
1129 * - "<branch>@{upstream}" finds the name of the other ref that
1130 *   <branch> is configured to merge with (missing <branch> defaults
1131 *   to the current branch), and places the name of the branch in the
1132 *   given buf and returns the number of characters parsed if
1133 *   successful.
1134 *
1135 * If the input is not of the accepted format, it returns a negative
1136 * number to signal an error.
1137 *
1138 * If the input was ok but there are not N branch switches in the
1139 * reflog, it returns 0.
1140 */
1141int interpret_branch_name(const char *name, int namelen, struct strbuf *buf)
1142{
1143        char *at;
1144        const char *start;
1145        int len = interpret_nth_prior_checkout(name, namelen, buf);
1146
1147        if (!namelen)
1148                namelen = strlen(name);
1149
1150        if (!len) {
1151                return len; /* syntax Ok, not enough switches */
1152        } else if (len > 0) {
1153                if (len == namelen)
1154                        return len; /* consumed all */
1155                else
1156                        return reinterpret(name, namelen, len, buf);
1157        }
1158
1159        for (start = name;
1160             (at = memchr(start, '@', namelen - (start - name)));
1161             start = at + 1) {
1162
1163                len = interpret_empty_at(name, namelen, at - name, buf);
1164                if (len > 0)
1165                        return reinterpret(name, namelen, len, buf);
1166
1167                len = interpret_branch_mark(name, namelen, at - name, buf,
1168                                            upstream_mark, branch_get_upstream);
1169                if (len > 0)
1170                        return len;
1171
1172                len = interpret_branch_mark(name, namelen, at - name, buf,
1173                                            push_mark, branch_get_push);
1174                if (len > 0)
1175                        return len;
1176        }
1177
1178        return -1;
1179}
1180
1181int strbuf_branchname(struct strbuf *sb, const char *name)
1182{
1183        int len = strlen(name);
1184        int used = interpret_branch_name(name, len, sb);
1185
1186        if (used == len)
1187                return 0;
1188        if (used < 0)
1189                used = 0;
1190        strbuf_add(sb, name + used, len - used);
1191        return len;
1192}
1193
1194int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
1195{
1196        strbuf_branchname(sb, name);
1197        if (name[0] == '-')
1198                return -1;
1199        strbuf_splice(sb, 0, 0, "refs/heads/", 11);
1200        return check_refname_format(sb->buf, 0);
1201}
1202
1203/*
1204 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
1205 * notably "xyz^" for "parent of xyz"
1206 */
1207int get_sha1(const char *name, unsigned char *sha1)
1208{
1209        struct object_context unused;
1210        return get_sha1_with_context(name, 0, sha1, &unused);
1211}
1212
1213/*
1214 * This is like "get_sha1()", but for struct object_id.
1215 */
1216int get_oid(const char *name, struct object_id *oid)
1217{
1218        return get_sha1(name, oid->hash);
1219}
1220
1221
1222/*
1223 * Many callers know that the user meant to name a commit-ish by
1224 * syntactical positions where the object name appears.  Calling this
1225 * function allows the machinery to disambiguate shorter-than-unique
1226 * abbreviated object names between commit-ish and others.
1227 *
1228 * Note that this does NOT error out when the named object is not a
1229 * commit-ish. It is merely to give a hint to the disambiguation
1230 * machinery.
1231 */
1232int get_sha1_committish(const char *name, unsigned char *sha1)
1233{
1234        struct object_context unused;
1235        return get_sha1_with_context(name, GET_SHA1_COMMITTISH,
1236                                     sha1, &unused);
1237}
1238
1239int get_sha1_treeish(const char *name, unsigned char *sha1)
1240{
1241        struct object_context unused;
1242        return get_sha1_with_context(name, GET_SHA1_TREEISH,
1243                                     sha1, &unused);
1244}
1245
1246int get_sha1_commit(const char *name, unsigned char *sha1)
1247{
1248        struct object_context unused;
1249        return get_sha1_with_context(name, GET_SHA1_COMMIT,
1250                                     sha1, &unused);
1251}
1252
1253int get_sha1_tree(const char *name, unsigned char *sha1)
1254{
1255        struct object_context unused;
1256        return get_sha1_with_context(name, GET_SHA1_TREE,
1257                                     sha1, &unused);
1258}
1259
1260int get_sha1_blob(const char *name, unsigned char *sha1)
1261{
1262        struct object_context unused;
1263        return get_sha1_with_context(name, GET_SHA1_BLOB,
1264                                     sha1, &unused);
1265}
1266
1267/* Must be called only when object_name:filename doesn't exist. */
1268static void diagnose_invalid_sha1_path(const char *prefix,
1269                                       const char *filename,
1270                                       const unsigned char *tree_sha1,
1271                                       const char *object_name,
1272                                       int object_name_len)
1273{
1274        unsigned char sha1[20];
1275        unsigned mode;
1276
1277        if (!prefix)
1278                prefix = "";
1279
1280        if (file_exists(filename))
1281                die("Path '%s' exists on disk, but not in '%.*s'.",
1282                    filename, object_name_len, object_name);
1283        if (errno == ENOENT || errno == ENOTDIR) {
1284                char *fullname = xstrfmt("%s%s", prefix, filename);
1285
1286                if (!get_tree_entry(tree_sha1, fullname,
1287                                    sha1, &mode)) {
1288                        die("Path '%s' exists, but not '%s'.\n"
1289                            "Did you mean '%.*s:%s' aka '%.*s:./%s'?",
1290                            fullname,
1291                            filename,
1292                            object_name_len, object_name,
1293                            fullname,
1294                            object_name_len, object_name,
1295                            filename);
1296                }
1297                die("Path '%s' does not exist in '%.*s'",
1298                    filename, object_name_len, object_name);
1299        }
1300}
1301
1302/* Must be called only when :stage:filename doesn't exist. */
1303static void diagnose_invalid_index_path(int stage,
1304                                        const char *prefix,
1305                                        const char *filename)
1306{
1307        const struct cache_entry *ce;
1308        int pos;
1309        unsigned namelen = strlen(filename);
1310        struct strbuf fullname = STRBUF_INIT;
1311
1312        if (!prefix)
1313                prefix = "";
1314
1315        /* Wrong stage number? */
1316        pos = cache_name_pos(filename, namelen);
1317        if (pos < 0)
1318                pos = -pos - 1;
1319        if (pos < active_nr) {
1320                ce = active_cache[pos];
1321                if (ce_namelen(ce) == namelen &&
1322                    !memcmp(ce->name, filename, namelen))
1323                        die("Path '%s' is in the index, but not at stage %d.\n"
1324                            "Did you mean ':%d:%s'?",
1325                            filename, stage,
1326                            ce_stage(ce), filename);
1327        }
1328
1329        /* Confusion between relative and absolute filenames? */
1330        strbuf_addstr(&fullname, prefix);
1331        strbuf_addstr(&fullname, filename);
1332        pos = cache_name_pos(fullname.buf, fullname.len);
1333        if (pos < 0)
1334                pos = -pos - 1;
1335        if (pos < active_nr) {
1336                ce = active_cache[pos];
1337                if (ce_namelen(ce) == fullname.len &&
1338                    !memcmp(ce->name, fullname.buf, fullname.len))
1339                        die("Path '%s' is in the index, but not '%s'.\n"
1340                            "Did you mean ':%d:%s' aka ':%d:./%s'?",
1341                            fullname.buf, filename,
1342                            ce_stage(ce), fullname.buf,
1343                            ce_stage(ce), filename);
1344        }
1345
1346        if (file_exists(filename))
1347                die("Path '%s' exists on disk, but not in the index.", filename);
1348        if (errno == ENOENT || errno == ENOTDIR)
1349                die("Path '%s' does not exist (neither on disk nor in the index).",
1350                    filename);
1351
1352        strbuf_release(&fullname);
1353}
1354
1355
1356static char *resolve_relative_path(const char *rel)
1357{
1358        if (!starts_with(rel, "./") && !starts_with(rel, "../"))
1359                return NULL;
1360
1361        if (!is_inside_work_tree())
1362                die("relative path syntax can't be used outside working tree.");
1363
1364        /* die() inside prefix_path() if resolved path is outside worktree */
1365        return prefix_path(startup_info->prefix,
1366                           startup_info->prefix ? strlen(startup_info->prefix) : 0,
1367                           rel);
1368}
1369
1370static int get_sha1_with_context_1(const char *name,
1371                                   unsigned flags,
1372                                   const char *prefix,
1373                                   unsigned char *sha1,
1374                                   struct object_context *oc)
1375{
1376        int ret, bracket_depth;
1377        int namelen = strlen(name);
1378        const char *cp;
1379        int only_to_die = flags & GET_SHA1_ONLY_TO_DIE;
1380
1381        memset(oc, 0, sizeof(*oc));
1382        oc->mode = S_IFINVALID;
1383        ret = get_sha1_1(name, namelen, sha1, flags);
1384        if (!ret)
1385                return ret;
1386        /*
1387         * sha1:path --> object name of path in ent sha1
1388         * :path -> object name of absolute path in index
1389         * :./path -> object name of path relative to cwd in index
1390         * :[0-3]:path -> object name of path in index at stage
1391         * :/foo -> recent commit matching foo
1392         */
1393        if (name[0] == ':') {
1394                int stage = 0;
1395                const struct cache_entry *ce;
1396                char *new_path = NULL;
1397                int pos;
1398                if (!only_to_die && namelen > 2 && name[1] == '/') {
1399                        struct commit_list *list = NULL;
1400
1401                        for_each_ref(handle_one_ref, &list);
1402                        commit_list_sort_by_date(&list);
1403                        return get_sha1_oneline(name + 2, sha1, list);
1404                }
1405                if (namelen < 3 ||
1406                    name[2] != ':' ||
1407                    name[1] < '0' || '3' < name[1])
1408                        cp = name + 1;
1409                else {
1410                        stage = name[1] - '0';
1411                        cp = name + 3;
1412                }
1413                new_path = resolve_relative_path(cp);
1414                if (!new_path) {
1415                        namelen = namelen - (cp - name);
1416                } else {
1417                        cp = new_path;
1418                        namelen = strlen(cp);
1419                }
1420
1421                strlcpy(oc->path, cp, sizeof(oc->path));
1422
1423                if (!active_cache)
1424                        read_cache();
1425                pos = cache_name_pos(cp, namelen);
1426                if (pos < 0)
1427                        pos = -pos - 1;
1428                while (pos < active_nr) {
1429                        ce = active_cache[pos];
1430                        if (ce_namelen(ce) != namelen ||
1431                            memcmp(ce->name, cp, namelen))
1432                                break;
1433                        if (ce_stage(ce) == stage) {
1434                                hashcpy(sha1, ce->oid.hash);
1435                                oc->mode = ce->ce_mode;
1436                                free(new_path);
1437                                return 0;
1438                        }
1439                        pos++;
1440                }
1441                if (only_to_die && name[1] && name[1] != '/')
1442                        diagnose_invalid_index_path(stage, prefix, cp);
1443                free(new_path);
1444                return -1;
1445        }
1446        for (cp = name, bracket_depth = 0; *cp; cp++) {
1447                if (*cp == '{')
1448                        bracket_depth++;
1449                else if (bracket_depth && *cp == '}')
1450                        bracket_depth--;
1451                else if (!bracket_depth && *cp == ':')
1452                        break;
1453        }
1454        if (*cp == ':') {
1455                unsigned char tree_sha1[20];
1456                int len = cp - name;
1457                if (!get_sha1_1(name, len, tree_sha1, GET_SHA1_TREEISH)) {
1458                        const char *filename = cp+1;
1459                        char *new_filename = NULL;
1460
1461                        new_filename = resolve_relative_path(filename);
1462                        if (new_filename)
1463                                filename = new_filename;
1464                        if (flags & GET_SHA1_FOLLOW_SYMLINKS) {
1465                                ret = get_tree_entry_follow_symlinks(tree_sha1,
1466                                        filename, sha1, &oc->symlink_path,
1467                                        &oc->mode);
1468                        } else {
1469                                ret = get_tree_entry(tree_sha1, filename,
1470                                                     sha1, &oc->mode);
1471                                if (ret && only_to_die) {
1472                                        diagnose_invalid_sha1_path(prefix,
1473                                                                   filename,
1474                                                                   tree_sha1,
1475                                                                   name, len);
1476                                }
1477                        }
1478                        hashcpy(oc->tree, tree_sha1);
1479                        strlcpy(oc->path, filename, sizeof(oc->path));
1480
1481                        free(new_filename);
1482                        return ret;
1483                } else {
1484                        if (only_to_die)
1485                                die("Invalid object name '%.*s'.", len, name);
1486                }
1487        }
1488        return ret;
1489}
1490
1491/*
1492 * Call this function when you know "name" given by the end user must
1493 * name an object but it doesn't; the function _may_ die with a better
1494 * diagnostic message than "no such object 'name'", e.g. "Path 'doc' does not
1495 * exist in 'HEAD'" when given "HEAD:doc", or it may return in which case
1496 * you have a chance to diagnose the error further.
1497 */
1498void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
1499{
1500        struct object_context oc;
1501        unsigned char sha1[20];
1502        get_sha1_with_context_1(name, GET_SHA1_ONLY_TO_DIE, prefix, sha1, &oc);
1503}
1504
1505int get_sha1_with_context(const char *str, unsigned flags, unsigned char *sha1, struct object_context *orc)
1506{
1507        if (flags & GET_SHA1_FOLLOW_SYMLINKS && flags & GET_SHA1_ONLY_TO_DIE)
1508                die("BUG: incompatible flags for get_sha1_with_context");
1509        return get_sha1_with_context_1(str, flags, NULL, sha1, orc);
1510}