sha1_name.con commit Merge branch 'jk/pretty-encoding-doc' into maint (caac7a3)
   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                const char *objdir = get_object_directory();
  90                int objdir_len = strlen(objdir);
  91                int entlen = objdir_len + 43;
  92                fakeent = xmalloc(sizeof(*fakeent) + entlen);
  93                memcpy(fakeent->base, objdir, objdir_len);
  94                fakeent->name = fakeent->base + objdir_len + 1;
  95                fakeent->name[-1] = '/';
  96        }
  97        fakeent->next = alt_odb_list;
  98
  99        sprintf(hex, "%.2s", hex_pfx);
 100        for (alt = fakeent; alt && !ds->ambiguous; alt = alt->next) {
 101                struct dirent *de;
 102                DIR *dir;
 103                sprintf(alt->name, "%.2s/", hex_pfx);
 104                dir = opendir(alt->base);
 105                if (!dir)
 106                        continue;
 107
 108                while (!ds->ambiguous && (de = readdir(dir)) != NULL) {
 109                        unsigned char sha1[20];
 110
 111                        if (strlen(de->d_name) != 38)
 112                                continue;
 113                        if (memcmp(de->d_name, hex_pfx + 2, len - 2))
 114                                continue;
 115                        memcpy(hex + 2, de->d_name, 38);
 116                        if (!get_sha1_hex(hex, sha1))
 117                                update_candidates(ds, sha1);
 118                }
 119                closedir(dir);
 120        }
 121}
 122
 123static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
 124{
 125        do {
 126                if (*a != *b)
 127                        return 0;
 128                a++;
 129                b++;
 130                len -= 2;
 131        } while (len > 1);
 132        if (len)
 133                if ((*a ^ *b) & 0xf0)
 134                        return 0;
 135        return 1;
 136}
 137
 138static void unique_in_pack(int len,
 139                          const unsigned char *bin_pfx,
 140                           struct packed_git *p,
 141                           struct disambiguate_state *ds)
 142{
 143        uint32_t num, last, i, first = 0;
 144        const unsigned char *current = NULL;
 145
 146        open_pack_index(p);
 147        num = p->num_objects;
 148        last = num;
 149        while (first < last) {
 150                uint32_t mid = (first + last) / 2;
 151                const unsigned char *current;
 152                int cmp;
 153
 154                current = nth_packed_object_sha1(p, mid);
 155                cmp = hashcmp(bin_pfx, current);
 156                if (!cmp) {
 157                        first = mid;
 158                        break;
 159                }
 160                if (cmp > 0) {
 161                        first = mid+1;
 162                        continue;
 163                }
 164                last = mid;
 165        }
 166
 167        /*
 168         * At this point, "first" is the location of the lowest object
 169         * with an object name that could match "bin_pfx".  See if we have
 170         * 0, 1 or more objects that actually match(es).
 171         */
 172        for (i = first; i < num && !ds->ambiguous; i++) {
 173                current = nth_packed_object_sha1(p, i);
 174                if (!match_sha(len, bin_pfx, current))
 175                        break;
 176                update_candidates(ds, current);
 177        }
 178}
 179
 180static void find_short_packed_object(int len, const unsigned char *bin_pfx,
 181                                     struct disambiguate_state *ds)
 182{
 183        struct packed_git *p;
 184
 185        prepare_packed_git();
 186        for (p = packed_git; p && !ds->ambiguous; p = p->next)
 187                unique_in_pack(len, bin_pfx, p, ds);
 188}
 189
 190#define SHORT_NAME_NOT_FOUND (-1)
 191#define SHORT_NAME_AMBIGUOUS (-2)
 192
 193static int finish_object_disambiguation(struct disambiguate_state *ds,
 194                                        unsigned char *sha1)
 195{
 196        if (ds->ambiguous)
 197                return SHORT_NAME_AMBIGUOUS;
 198
 199        if (!ds->candidate_exists)
 200                return SHORT_NAME_NOT_FOUND;
 201
 202        if (!ds->candidate_checked)
 203                /*
 204                 * If this is the only candidate, there is no point
 205                 * calling the disambiguation hint callback.
 206                 *
 207                 * On the other hand, if the current candidate
 208                 * replaced an earlier candidate that did _not_ pass
 209                 * the disambiguation hint callback, then we do have
 210                 * more than one objects that match the short name
 211                 * given, so we should make sure this one matches;
 212                 * otherwise, if we discovered this one and the one
 213                 * that we previously discarded in the reverse order,
 214                 * we would end up showing different results in the
 215                 * same repository!
 216                 */
 217                ds->candidate_ok = (!ds->disambiguate_fn_used ||
 218                                    ds->fn(ds->candidate, ds->cb_data));
 219
 220        if (!ds->candidate_ok)
 221                return SHORT_NAME_AMBIGUOUS;
 222
 223        hashcpy(sha1, ds->candidate);
 224        return 0;
 225}
 226
 227static int disambiguate_commit_only(const unsigned char *sha1, void *cb_data_unused)
 228{
 229        int kind = sha1_object_info(sha1, NULL);
 230        return kind == OBJ_COMMIT;
 231}
 232
 233static int disambiguate_committish_only(const unsigned char *sha1, void *cb_data_unused)
 234{
 235        struct object *obj;
 236        int kind;
 237
 238        kind = sha1_object_info(sha1, NULL);
 239        if (kind == OBJ_COMMIT)
 240                return 1;
 241        if (kind != OBJ_TAG)
 242                return 0;
 243
 244        /* We need to do this the hard way... */
 245        obj = deref_tag(parse_object(sha1), NULL, 0);
 246        if (obj && obj->type == OBJ_COMMIT)
 247                return 1;
 248        return 0;
 249}
 250
 251static int disambiguate_tree_only(const unsigned char *sha1, void *cb_data_unused)
 252{
 253        int kind = sha1_object_info(sha1, NULL);
 254        return kind == OBJ_TREE;
 255}
 256
 257static int disambiguate_treeish_only(const unsigned char *sha1, void *cb_data_unused)
 258{
 259        struct object *obj;
 260        int kind;
 261
 262        kind = sha1_object_info(sha1, NULL);
 263        if (kind == OBJ_TREE || kind == OBJ_COMMIT)
 264                return 1;
 265        if (kind != OBJ_TAG)
 266                return 0;
 267
 268        /* We need to do this the hard way... */
 269        obj = deref_tag(lookup_object(sha1), NULL, 0);
 270        if (obj && (obj->type == OBJ_TREE || obj->type == OBJ_COMMIT))
 271                return 1;
 272        return 0;
 273}
 274
 275static int disambiguate_blob_only(const unsigned char *sha1, void *cb_data_unused)
 276{
 277        int kind = sha1_object_info(sha1, NULL);
 278        return kind == OBJ_BLOB;
 279}
 280
 281static int prepare_prefixes(const char *name, int len,
 282                            unsigned char *bin_pfx,
 283                            char *hex_pfx)
 284{
 285        int i;
 286
 287        hashclr(bin_pfx);
 288        memset(hex_pfx, 'x', 40);
 289        for (i = 0; i < len ;i++) {
 290                unsigned char c = name[i];
 291                unsigned char val;
 292                if (c >= '0' && c <= '9')
 293                        val = c - '0';
 294                else if (c >= 'a' && c <= 'f')
 295                        val = c - 'a' + 10;
 296                else if (c >= 'A' && c <='F') {
 297                        val = c - 'A' + 10;
 298                        c -= 'A' - 'a';
 299                }
 300                else
 301                        return -1;
 302                hex_pfx[i] = c;
 303                if (!(i & 1))
 304                        val <<= 4;
 305                bin_pfx[i >> 1] |= val;
 306        }
 307        return 0;
 308}
 309
 310static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 311                          unsigned flags)
 312{
 313        int status;
 314        char hex_pfx[40];
 315        unsigned char bin_pfx[20];
 316        struct disambiguate_state ds;
 317        int quietly = !!(flags & GET_SHA1_QUIETLY);
 318
 319        if (len < MINIMUM_ABBREV || len > 40)
 320                return -1;
 321        if (prepare_prefixes(name, len, bin_pfx, hex_pfx) < 0)
 322                return -1;
 323
 324        prepare_alt_odb();
 325
 326        memset(&ds, 0, sizeof(ds));
 327        if (flags & GET_SHA1_COMMIT)
 328                ds.fn = disambiguate_commit_only;
 329        else if (flags & GET_SHA1_COMMITTISH)
 330                ds.fn = disambiguate_committish_only;
 331        else if (flags & GET_SHA1_TREE)
 332                ds.fn = disambiguate_tree_only;
 333        else if (flags & GET_SHA1_TREEISH)
 334                ds.fn = disambiguate_treeish_only;
 335        else if (flags & GET_SHA1_BLOB)
 336                ds.fn = disambiguate_blob_only;
 337
 338        find_short_object_filename(len, hex_pfx, &ds);
 339        find_short_packed_object(len, bin_pfx, &ds);
 340        status = finish_object_disambiguation(&ds, sha1);
 341
 342        if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
 343                return error("short SHA1 %.*s is ambiguous.", len, hex_pfx);
 344        return status;
 345}
 346
 347int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
 348{
 349        char hex_pfx[40];
 350        unsigned char bin_pfx[20];
 351        struct disambiguate_state ds;
 352        int len = strlen(prefix);
 353
 354        if (len < MINIMUM_ABBREV || len > 40)
 355                return -1;
 356        if (prepare_prefixes(prefix, len, bin_pfx, hex_pfx) < 0)
 357                return -1;
 358
 359        prepare_alt_odb();
 360
 361        memset(&ds, 0, sizeof(ds));
 362        ds.always_call_fn = 1;
 363        ds.cb_data = cb_data;
 364        ds.fn = fn;
 365
 366        find_short_object_filename(len, hex_pfx, &ds);
 367        find_short_packed_object(len, bin_pfx, &ds);
 368        return ds.ambiguous;
 369}
 370
 371const char *find_unique_abbrev(const unsigned char *sha1, int len)
 372{
 373        int status, exists;
 374        static char hex[41];
 375
 376        memcpy(hex, sha1_to_hex(sha1), 40);
 377        if (len == 40 || !len)
 378                return hex;
 379        exists = has_sha1_file(sha1);
 380        while (len < 40) {
 381                unsigned char sha1_ret[20];
 382                status = get_short_sha1(hex, len, sha1_ret, GET_SHA1_QUIETLY);
 383                if (exists
 384                    ? !status
 385                    : status == SHORT_NAME_NOT_FOUND) {
 386                        hex[len] = 0;
 387                        return hex;
 388                }
 389                len++;
 390        }
 391        return hex;
 392}
 393
 394static int ambiguous_path(const char *path, int len)
 395{
 396        int slash = 1;
 397        int cnt;
 398
 399        for (cnt = 0; cnt < len; cnt++) {
 400                switch (*path++) {
 401                case '\0':
 402                        break;
 403                case '/':
 404                        if (slash)
 405                                break;
 406                        slash = 1;
 407                        continue;
 408                case '.':
 409                        continue;
 410                default:
 411                        slash = 0;
 412                        continue;
 413                }
 414                break;
 415        }
 416        return slash;
 417}
 418
 419static inline int upstream_mark(const char *string, int len)
 420{
 421        const char *suffix[] = { "@{upstream}", "@{u}" };
 422        int i;
 423
 424        for (i = 0; i < ARRAY_SIZE(suffix); i++) {
 425                int suffix_len = strlen(suffix[i]);
 426                if (suffix_len <= len
 427                    && !memcmp(string, suffix[i], suffix_len))
 428                        return suffix_len;
 429        }
 430        return 0;
 431}
 432
 433static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags);
 434static int interpret_nth_prior_checkout(const char *name, int namelen, struct strbuf *buf);
 435
 436static int get_sha1_basic(const char *str, int len, unsigned char *sha1,
 437                          unsigned int flags)
 438{
 439        static const char *warn_msg = "refname '%.*s' is ambiguous.";
 440        static const char *object_name_msg = N_(
 441        "Git normally never creates a ref that ends with 40 hex characters\n"
 442        "because it will be ignored when you just specify 40-hex. These refs\n"
 443        "may be created by mistake. For example,\n"
 444        "\n"
 445        "  git checkout -b $br $(git rev-parse ...)\n"
 446        "\n"
 447        "where \"$br\" is somehow empty and a 40-hex ref is created. Please\n"
 448        "examine these refs and maybe delete them. Turn this message off by\n"
 449        "running \"git config advice.objectNameWarning false\"");
 450        unsigned char tmp_sha1[20];
 451        char *real_ref = NULL;
 452        int refs_found = 0;
 453        int at, reflog_len, nth_prior = 0;
 454
 455        if (len == 40 && !get_sha1_hex(str, sha1)) {
 456                if (warn_ambiguous_refs && warn_on_object_refname_ambiguity) {
 457                        refs_found = dwim_ref(str, len, tmp_sha1, &real_ref);
 458                        if (refs_found > 0) {
 459                                warning(warn_msg, len, str);
 460                                if (advice_object_name_warning)
 461                                        fprintf(stderr, "%s\n", _(object_name_msg));
 462                        }
 463                        free(real_ref);
 464                }
 465                return 0;
 466        }
 467
 468        /* basic@{time or number or -number} format to query ref-log */
 469        reflog_len = at = 0;
 470        if (len && str[len-1] == '}') {
 471                for (at = len-4; at >= 0; at--) {
 472                        if (str[at] == '@' && str[at+1] == '{') {
 473                                if (str[at+2] == '-') {
 474                                        if (at != 0)
 475                                                /* @{-N} not at start */
 476                                                return -1;
 477                                        nth_prior = 1;
 478                                        continue;
 479                                }
 480                                if (!upstream_mark(str + at, len - at)) {
 481                                        reflog_len = (len-1) - (at+2);
 482                                        len = at;
 483                                }
 484                                break;
 485                        }
 486                }
 487        }
 488
 489        /* Accept only unambiguous ref paths. */
 490        if (len && ambiguous_path(str, len))
 491                return -1;
 492
 493        if (nth_prior) {
 494                struct strbuf buf = STRBUF_INIT;
 495                int detached;
 496
 497                if (interpret_nth_prior_checkout(str, len, &buf) > 0) {
 498                        detached = (buf.len == 40 && !get_sha1_hex(buf.buf, sha1));
 499                        strbuf_release(&buf);
 500                        if (detached)
 501                                return 0;
 502                }
 503        }
 504
 505        if (!len && reflog_len)
 506                /* allow "@{...}" to mean the current branch reflog */
 507                refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
 508        else if (reflog_len)
 509                refs_found = dwim_log(str, len, sha1, &real_ref);
 510        else
 511                refs_found = dwim_ref(str, len, sha1, &real_ref);
 512
 513        if (!refs_found)
 514                return -1;
 515
 516        if (warn_ambiguous_refs && !(flags & GET_SHA1_QUIETLY) &&
 517            (refs_found > 1 ||
 518             !get_short_sha1(str, len, tmp_sha1, GET_SHA1_QUIETLY)))
 519                warning(warn_msg, len, str);
 520
 521        if (reflog_len) {
 522                int nth, i;
 523                unsigned long at_time;
 524                unsigned long co_time;
 525                int co_tz, co_cnt;
 526
 527                /* Is it asking for N-th entry, or approxidate? */
 528                for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 529                        char ch = str[at+2+i];
 530                        if ('0' <= ch && ch <= '9')
 531                                nth = nth * 10 + ch - '0';
 532                        else
 533                                nth = -1;
 534                }
 535                if (100000000 <= nth) {
 536                        at_time = nth;
 537                        nth = -1;
 538                } else if (0 <= nth)
 539                        at_time = 0;
 540                else {
 541                        int errors = 0;
 542                        char *tmp = xstrndup(str + at + 2, reflog_len);
 543                        at_time = approxidate_careful(tmp, &errors);
 544                        free(tmp);
 545                        if (errors) {
 546                                free(real_ref);
 547                                return -1;
 548                        }
 549                }
 550                if (read_ref_at(real_ref, flags, at_time, nth, sha1, NULL,
 551                                &co_time, &co_tz, &co_cnt)) {
 552                        if (!len) {
 553                                if (starts_with(real_ref, "refs/heads/")) {
 554                                        str = real_ref + 11;
 555                                        len = strlen(real_ref + 11);
 556                                } else {
 557                                        /* detached HEAD */
 558                                        str = "HEAD";
 559                                        len = 4;
 560                                }
 561                        }
 562                        if (at_time) {
 563                                if (!(flags & GET_SHA1_QUIETLY)) {
 564                                        warning("Log for '%.*s' only goes "
 565                                                "back to %s.", len, str,
 566                                                show_date(co_time, co_tz, DATE_RFC2822));
 567                                }
 568                        } else {
 569                                if (flags & GET_SHA1_QUIETLY) {
 570                                        exit(128);
 571                                }
 572                                die("Log for '%.*s' only has %d entries.",
 573                                    len, str, co_cnt);
 574                        }
 575                }
 576        }
 577
 578        free(real_ref);
 579        return 0;
 580}
 581
 582static int get_parent(const char *name, int len,
 583                      unsigned char *result, int idx)
 584{
 585        unsigned char sha1[20];
 586        int ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 587        struct commit *commit;
 588        struct commit_list *p;
 589
 590        if (ret)
 591                return ret;
 592        commit = lookup_commit_reference(sha1);
 593        if (parse_commit(commit))
 594                return -1;
 595        if (!idx) {
 596                hashcpy(result, commit->object.sha1);
 597                return 0;
 598        }
 599        p = commit->parents;
 600        while (p) {
 601                if (!--idx) {
 602                        hashcpy(result, p->item->object.sha1);
 603                        return 0;
 604                }
 605                p = p->next;
 606        }
 607        return -1;
 608}
 609
 610static int get_nth_ancestor(const char *name, int len,
 611                            unsigned char *result, int generation)
 612{
 613        unsigned char sha1[20];
 614        struct commit *commit;
 615        int ret;
 616
 617        ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 618        if (ret)
 619                return ret;
 620        commit = lookup_commit_reference(sha1);
 621        if (!commit)
 622                return -1;
 623
 624        while (generation--) {
 625                if (parse_commit(commit) || !commit->parents)
 626                        return -1;
 627                commit = commit->parents->item;
 628        }
 629        hashcpy(result, commit->object.sha1);
 630        return 0;
 631}
 632
 633struct object *peel_to_type(const char *name, int namelen,
 634                            struct object *o, enum object_type expected_type)
 635{
 636        if (name && !namelen)
 637                namelen = strlen(name);
 638        while (1) {
 639                if (!o || (!o->parsed && !parse_object(o->sha1)))
 640                        return NULL;
 641                if (expected_type == OBJ_ANY || o->type == expected_type)
 642                        return o;
 643                if (o->type == OBJ_TAG)
 644                        o = ((struct tag*) o)->tagged;
 645                else if (o->type == OBJ_COMMIT)
 646                        o = &(((struct commit *) o)->tree->object);
 647                else {
 648                        if (name)
 649                                error("%.*s: expected %s type, but the object "
 650                                      "dereferences to %s type",
 651                                      namelen, name, typename(expected_type),
 652                                      typename(o->type));
 653                        return NULL;
 654                }
 655        }
 656}
 657
 658static int peel_onion(const char *name, int len, unsigned char *sha1)
 659{
 660        unsigned char outer[20];
 661        const char *sp;
 662        unsigned int expected_type = 0;
 663        unsigned lookup_flags = 0;
 664        struct object *o;
 665
 666        /*
 667         * "ref^{type}" dereferences ref repeatedly until you cannot
 668         * dereference anymore, or you get an object of given type,
 669         * whichever comes first.  "ref^{}" means just dereference
 670         * tags until you get a non-tag.  "ref^0" is a shorthand for
 671         * "ref^{commit}".  "commit^{tree}" could be used to find the
 672         * top-level tree of the given commit.
 673         */
 674        if (len < 4 || name[len-1] != '}')
 675                return -1;
 676
 677        for (sp = name + len - 1; name <= sp; sp--) {
 678                int ch = *sp;
 679                if (ch == '{' && name < sp && sp[-1] == '^')
 680                        break;
 681        }
 682        if (sp <= name)
 683                return -1;
 684
 685        sp++; /* beginning of type name, or closing brace for empty */
 686        if (starts_with(sp, "commit}"))
 687                expected_type = OBJ_COMMIT;
 688        else if (starts_with(sp, "tag}"))
 689                expected_type = OBJ_TAG;
 690        else if (starts_with(sp, "tree}"))
 691                expected_type = OBJ_TREE;
 692        else if (starts_with(sp, "blob}"))
 693                expected_type = OBJ_BLOB;
 694        else if (starts_with(sp, "object}"))
 695                expected_type = OBJ_ANY;
 696        else if (sp[0] == '}')
 697                expected_type = OBJ_NONE;
 698        else if (sp[0] == '/')
 699                expected_type = OBJ_COMMIT;
 700        else
 701                return -1;
 702
 703        if (expected_type == OBJ_COMMIT)
 704                lookup_flags = GET_SHA1_COMMITTISH;
 705        else if (expected_type == OBJ_TREE)
 706                lookup_flags = GET_SHA1_TREEISH;
 707
 708        if (get_sha1_1(name, sp - name - 2, outer, lookup_flags))
 709                return -1;
 710
 711        o = parse_object(outer);
 712        if (!o)
 713                return -1;
 714        if (!expected_type) {
 715                o = deref_tag(o, name, sp - name - 2);
 716                if (!o || (!o->parsed && !parse_object(o->sha1)))
 717                        return -1;
 718                hashcpy(sha1, o->sha1);
 719                return 0;
 720        }
 721
 722        /*
 723         * At this point, the syntax look correct, so
 724         * if we do not get the needed object, we should
 725         * barf.
 726         */
 727        o = peel_to_type(name, len, o, expected_type);
 728        if (!o)
 729                return -1;
 730
 731        hashcpy(sha1, o->sha1);
 732        if (sp[0] == '/') {
 733                /* "$commit^{/foo}" */
 734                char *prefix;
 735                int ret;
 736                struct commit_list *list = NULL;
 737
 738                /*
 739                 * $commit^{/}. Some regex implementation may reject.
 740                 * We don't need regex anyway. '' pattern always matches.
 741                 */
 742                if (sp[1] == '}')
 743                        return 0;
 744
 745                prefix = xstrndup(sp + 1, name + len - 1 - (sp + 1));
 746                commit_list_insert((struct commit *)o, &list);
 747                ret = get_sha1_oneline(prefix, sha1, list);
 748                free(prefix);
 749                return ret;
 750        }
 751        return 0;
 752}
 753
 754static int get_describe_name(const char *name, int len, unsigned char *sha1)
 755{
 756        const char *cp;
 757        unsigned flags = GET_SHA1_QUIETLY | GET_SHA1_COMMIT;
 758
 759        for (cp = name + len - 1; name + 2 <= cp; cp--) {
 760                char ch = *cp;
 761                if (!isxdigit(ch)) {
 762                        /* We must be looking at g in "SOMETHING-g"
 763                         * for it to be describe output.
 764                         */
 765                        if (ch == 'g' && cp[-1] == '-') {
 766                                cp++;
 767                                len -= cp - name;
 768                                return get_short_sha1(cp, len, sha1, flags);
 769                        }
 770                }
 771        }
 772        return -1;
 773}
 774
 775static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags)
 776{
 777        int ret, has_suffix;
 778        const char *cp;
 779
 780        /*
 781         * "name~3" is "name^^^", "name~" is "name~1", and "name^" is "name^1".
 782         */
 783        has_suffix = 0;
 784        for (cp = name + len - 1; name <= cp; cp--) {
 785                int ch = *cp;
 786                if ('0' <= ch && ch <= '9')
 787                        continue;
 788                if (ch == '~' || ch == '^')
 789                        has_suffix = ch;
 790                break;
 791        }
 792
 793        if (has_suffix) {
 794                int num = 0;
 795                int len1 = cp - name;
 796                cp++;
 797                while (cp < name + len)
 798                        num = num * 10 + *cp++ - '0';
 799                if (!num && len1 == len - 1)
 800                        num = 1;
 801                if (has_suffix == '^')
 802                        return get_parent(name, len1, sha1, num);
 803                /* else if (has_suffix == '~') -- goes without saying */
 804                return get_nth_ancestor(name, len1, sha1, num);
 805        }
 806
 807        ret = peel_onion(name, len, sha1);
 808        if (!ret)
 809                return 0;
 810
 811        ret = get_sha1_basic(name, len, sha1, lookup_flags);
 812        if (!ret)
 813                return 0;
 814
 815        /* It could be describe output that is "SOMETHING-gXXXX" */
 816        ret = get_describe_name(name, len, sha1);
 817        if (!ret)
 818                return 0;
 819
 820        return get_short_sha1(name, len, sha1, lookup_flags);
 821}
 822
 823/*
 824 * This interprets names like ':/Initial revision of "git"' by searching
 825 * through history and returning the first commit whose message starts
 826 * the given regular expression.
 827 *
 828 * For future extension, ':/!' is reserved. If you want to match a message
 829 * beginning with a '!', you have to repeat the exclamation mark.
 830 */
 831
 832/* Remember to update object flag allocation in object.h */
 833#define ONELINE_SEEN (1u<<20)
 834
 835static int handle_one_ref(const char *path,
 836                const unsigned char *sha1, int flag, void *cb_data)
 837{
 838        struct commit_list **list = cb_data;
 839        struct object *object = parse_object(sha1);
 840        if (!object)
 841                return 0;
 842        if (object->type == OBJ_TAG) {
 843                object = deref_tag(object, path, strlen(path));
 844                if (!object)
 845                        return 0;
 846        }
 847        if (object->type != OBJ_COMMIT)
 848                return 0;
 849        commit_list_insert((struct commit *)object, list);
 850        return 0;
 851}
 852
 853static int get_sha1_oneline(const char *prefix, unsigned char *sha1,
 854                            struct commit_list *list)
 855{
 856        struct commit_list *backup = NULL, *l;
 857        int found = 0;
 858        regex_t regex;
 859
 860        if (prefix[0] == '!') {
 861                if (prefix[1] != '!')
 862                        die ("Invalid search pattern: %s", prefix);
 863                prefix++;
 864        }
 865
 866        if (regcomp(&regex, prefix, REG_EXTENDED))
 867                die("Invalid search pattern: %s", prefix);
 868
 869        for (l = list; l; l = l->next) {
 870                l->item->object.flags |= ONELINE_SEEN;
 871                commit_list_insert(l->item, &backup);
 872        }
 873        while (list) {
 874                const char *p, *buf;
 875                struct commit *commit;
 876                int matches;
 877
 878                commit = pop_most_recent_commit(&list, ONELINE_SEEN);
 879                if (!parse_object(commit->object.sha1))
 880                        continue;
 881                buf = get_commit_buffer(commit, NULL);
 882                p = strstr(buf, "\n\n");
 883                matches = p && !regexec(&regex, p + 2, 0, NULL, 0);
 884                unuse_commit_buffer(commit, buf);
 885
 886                if (matches) {
 887                        hashcpy(sha1, commit->object.sha1);
 888                        found = 1;
 889                        break;
 890                }
 891        }
 892        regfree(&regex);
 893        free_commit_list(list);
 894        for (l = backup; l; l = l->next)
 895                clear_commit_marks(l->item, ONELINE_SEEN);
 896        free_commit_list(backup);
 897        return found ? 0 : -1;
 898}
 899
 900struct grab_nth_branch_switch_cbdata {
 901        int remaining;
 902        struct strbuf buf;
 903};
 904
 905static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
 906                                  const char *email, unsigned long timestamp, int tz,
 907                                  const char *message, void *cb_data)
 908{
 909        struct grab_nth_branch_switch_cbdata *cb = cb_data;
 910        const char *match = NULL, *target = NULL;
 911        size_t len;
 912
 913        if (skip_prefix(message, "checkout: moving from ", &match))
 914                target = strstr(match, " to ");
 915
 916        if (!match || !target)
 917                return 0;
 918        if (--(cb->remaining) == 0) {
 919                len = target - match;
 920                strbuf_reset(&cb->buf);
 921                strbuf_add(&cb->buf, match, len);
 922                return 1; /* we are done */
 923        }
 924        return 0;
 925}
 926
 927/*
 928 * Parse @{-N} syntax, return the number of characters parsed
 929 * if successful; otherwise signal an error with negative value.
 930 */
 931static int interpret_nth_prior_checkout(const char *name, int namelen,
 932                                        struct strbuf *buf)
 933{
 934        long nth;
 935        int retval;
 936        struct grab_nth_branch_switch_cbdata cb;
 937        const char *brace;
 938        char *num_end;
 939
 940        if (namelen < 4)
 941                return -1;
 942        if (name[0] != '@' || name[1] != '{' || name[2] != '-')
 943                return -1;
 944        brace = memchr(name, '}', namelen);
 945        if (!brace)
 946                return -1;
 947        nth = strtol(name + 3, &num_end, 10);
 948        if (num_end != brace)
 949                return -1;
 950        if (nth <= 0)
 951                return -1;
 952        cb.remaining = nth;
 953        strbuf_init(&cb.buf, 20);
 954
 955        retval = 0;
 956        if (0 < for_each_reflog_ent_reverse("HEAD", grab_nth_branch_switch, &cb)) {
 957                strbuf_reset(buf);
 958                strbuf_addbuf(buf, &cb.buf);
 959                retval = brace - name + 1;
 960        }
 961
 962        strbuf_release(&cb.buf);
 963        return retval;
 964}
 965
 966int get_sha1_mb(const char *name, unsigned char *sha1)
 967{
 968        struct commit *one, *two;
 969        struct commit_list *mbs;
 970        unsigned char sha1_tmp[20];
 971        const char *dots;
 972        int st;
 973
 974        dots = strstr(name, "...");
 975        if (!dots)
 976                return get_sha1(name, sha1);
 977        if (dots == name)
 978                st = get_sha1("HEAD", sha1_tmp);
 979        else {
 980                struct strbuf sb;
 981                strbuf_init(&sb, dots - name);
 982                strbuf_add(&sb, name, dots - name);
 983                st = get_sha1_committish(sb.buf, sha1_tmp);
 984                strbuf_release(&sb);
 985        }
 986        if (st)
 987                return st;
 988        one = lookup_commit_reference_gently(sha1_tmp, 0);
 989        if (!one)
 990                return -1;
 991
 992        if (get_sha1_committish(dots[3] ? (dots + 3) : "HEAD", sha1_tmp))
 993                return -1;
 994        two = lookup_commit_reference_gently(sha1_tmp, 0);
 995        if (!two)
 996                return -1;
 997        mbs = get_merge_bases(one, two);
 998        if (!mbs || mbs->next)
 999                st = -1;
1000        else {
1001                st = 0;
1002                hashcpy(sha1, mbs->item->object.sha1);
1003        }
1004        free_commit_list(mbs);
1005        return st;
1006}
1007
1008/* parse @something syntax, when 'something' is not {.*} */
1009static int interpret_empty_at(const char *name, int namelen, int len, struct strbuf *buf)
1010{
1011        const char *next;
1012
1013        if (len || name[1] == '{')
1014                return -1;
1015
1016        /* make sure it's a single @, or @@{.*}, not @foo */
1017        next = memchr(name + len + 1, '@', namelen - len - 1);
1018        if (next && next[1] != '{')
1019                return -1;
1020        if (!next)
1021                next = name + namelen;
1022        if (next != name + 1)
1023                return -1;
1024
1025        strbuf_reset(buf);
1026        strbuf_add(buf, "HEAD", 4);
1027        return 1;
1028}
1029
1030static int reinterpret(const char *name, int namelen, int len, struct strbuf *buf)
1031{
1032        /* we have extra data, which might need further processing */
1033        struct strbuf tmp = STRBUF_INIT;
1034        int used = buf->len;
1035        int ret;
1036
1037        strbuf_add(buf, name + len, namelen - len);
1038        ret = interpret_branch_name(buf->buf, buf->len, &tmp);
1039        /* that data was not interpreted, remove our cruft */
1040        if (ret < 0) {
1041                strbuf_setlen(buf, used);
1042                return len;
1043        }
1044        strbuf_reset(buf);
1045        strbuf_addbuf(buf, &tmp);
1046        strbuf_release(&tmp);
1047        /* tweak for size of {-N} versus expanded ref name */
1048        return ret - used + len;
1049}
1050
1051static void set_shortened_ref(struct strbuf *buf, const char *ref)
1052{
1053        char *s = shorten_unambiguous_ref(ref, 0);
1054        strbuf_reset(buf);
1055        strbuf_addstr(buf, s);
1056        free(s);
1057}
1058
1059static const char *get_upstream_branch(const char *branch_buf, int len)
1060{
1061        char *branch = xstrndup(branch_buf, len);
1062        struct branch *upstream = branch_get(*branch ? branch : NULL);
1063
1064        /*
1065         * Upstream can be NULL only if branch refers to HEAD and HEAD
1066         * points to something different than a branch.
1067         */
1068        if (!upstream)
1069                die(_("HEAD does not point to a branch"));
1070        if (!upstream->merge || !upstream->merge[0]->dst) {
1071                if (!ref_exists(upstream->refname))
1072                        die(_("No such branch: '%s'"), branch);
1073                if (!upstream->merge) {
1074                        die(_("No upstream configured for branch '%s'"),
1075                                upstream->name);
1076                }
1077                die(
1078                        _("Upstream branch '%s' not stored as a remote-tracking branch"),
1079                        upstream->merge[0]->src);
1080        }
1081        free(branch);
1082
1083        return upstream->merge[0]->dst;
1084}
1085
1086static int interpret_upstream_mark(const char *name, int namelen,
1087                                   int at, struct strbuf *buf)
1088{
1089        int len;
1090
1091        len = upstream_mark(name + at, namelen - at);
1092        if (!len)
1093                return -1;
1094
1095        if (memchr(name, ':', at))
1096                return -1;
1097
1098        set_shortened_ref(buf, get_upstream_branch(name, at));
1099        return len + at;
1100}
1101
1102/*
1103 * This reads short-hand syntax that not only evaluates to a commit
1104 * object name, but also can act as if the end user spelled the name
1105 * of the branch from the command line.
1106 *
1107 * - "@{-N}" finds the name of the Nth previous branch we were on, and
1108 *   places the name of the branch in the given buf and returns the
1109 *   number of characters parsed if successful.
1110 *
1111 * - "<branch>@{upstream}" finds the name of the other ref that
1112 *   <branch> is configured to merge with (missing <branch> defaults
1113 *   to the current branch), and places the name of the branch in the
1114 *   given buf and returns the number of characters parsed if
1115 *   successful.
1116 *
1117 * If the input is not of the accepted format, it returns a negative
1118 * number to signal an error.
1119 *
1120 * If the input was ok but there are not N branch switches in the
1121 * reflog, it returns 0.
1122 */
1123int interpret_branch_name(const char *name, int namelen, struct strbuf *buf)
1124{
1125        char *at;
1126        const char *start;
1127        int len = interpret_nth_prior_checkout(name, namelen, buf);
1128
1129        if (!namelen)
1130                namelen = strlen(name);
1131
1132        if (!len) {
1133                return len; /* syntax Ok, not enough switches */
1134        } else if (len > 0) {
1135                if (len == namelen)
1136                        return len; /* consumed all */
1137                else
1138                        return reinterpret(name, namelen, len, buf);
1139        }
1140
1141        for (start = name;
1142             (at = memchr(start, '@', namelen - (start - name)));
1143             start = at + 1) {
1144
1145                len = interpret_empty_at(name, namelen, at - name, buf);
1146                if (len > 0)
1147                        return reinterpret(name, namelen, len, buf);
1148
1149                len = interpret_upstream_mark(name, namelen, at - name, buf);
1150                if (len > 0)
1151                        return len;
1152        }
1153
1154        return -1;
1155}
1156
1157int strbuf_branchname(struct strbuf *sb, const char *name)
1158{
1159        int len = strlen(name);
1160        int used = interpret_branch_name(name, len, sb);
1161
1162        if (used == len)
1163                return 0;
1164        if (used < 0)
1165                used = 0;
1166        strbuf_add(sb, name + used, len - used);
1167        return len;
1168}
1169
1170int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
1171{
1172        strbuf_branchname(sb, name);
1173        if (name[0] == '-')
1174                return -1;
1175        strbuf_splice(sb, 0, 0, "refs/heads/", 11);
1176        return check_refname_format(sb->buf, 0);
1177}
1178
1179/*
1180 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
1181 * notably "xyz^" for "parent of xyz"
1182 */
1183int get_sha1(const char *name, unsigned char *sha1)
1184{
1185        struct object_context unused;
1186        return get_sha1_with_context(name, 0, sha1, &unused);
1187}
1188
1189/*
1190 * Many callers know that the user meant to name a commit-ish by
1191 * syntactical positions where the object name appears.  Calling this
1192 * function allows the machinery to disambiguate shorter-than-unique
1193 * abbreviated object names between commit-ish and others.
1194 *
1195 * Note that this does NOT error out when the named object is not a
1196 * commit-ish. It is merely to give a hint to the disambiguation
1197 * machinery.
1198 */
1199int get_sha1_committish(const char *name, unsigned char *sha1)
1200{
1201        struct object_context unused;
1202        return get_sha1_with_context(name, GET_SHA1_COMMITTISH,
1203                                     sha1, &unused);
1204}
1205
1206int get_sha1_treeish(const char *name, unsigned char *sha1)
1207{
1208        struct object_context unused;
1209        return get_sha1_with_context(name, GET_SHA1_TREEISH,
1210                                     sha1, &unused);
1211}
1212
1213int get_sha1_commit(const char *name, unsigned char *sha1)
1214{
1215        struct object_context unused;
1216        return get_sha1_with_context(name, GET_SHA1_COMMIT,
1217                                     sha1, &unused);
1218}
1219
1220int get_sha1_tree(const char *name, unsigned char *sha1)
1221{
1222        struct object_context unused;
1223        return get_sha1_with_context(name, GET_SHA1_TREE,
1224                                     sha1, &unused);
1225}
1226
1227int get_sha1_blob(const char *name, unsigned char *sha1)
1228{
1229        struct object_context unused;
1230        return get_sha1_with_context(name, GET_SHA1_BLOB,
1231                                     sha1, &unused);
1232}
1233
1234/* Must be called only when object_name:filename doesn't exist. */
1235static void diagnose_invalid_sha1_path(const char *prefix,
1236                                       const char *filename,
1237                                       const unsigned char *tree_sha1,
1238                                       const char *object_name,
1239                                       int object_name_len)
1240{
1241        unsigned char sha1[20];
1242        unsigned mode;
1243
1244        if (!prefix)
1245                prefix = "";
1246
1247        if (file_exists(filename))
1248                die("Path '%s' exists on disk, but not in '%.*s'.",
1249                    filename, object_name_len, object_name);
1250        if (errno == ENOENT || errno == ENOTDIR) {
1251                char *fullname = xstrfmt("%s%s", prefix, filename);
1252
1253                if (!get_tree_entry(tree_sha1, fullname,
1254                                    sha1, &mode)) {
1255                        die("Path '%s' exists, but not '%s'.\n"
1256                            "Did you mean '%.*s:%s' aka '%.*s:./%s'?",
1257                            fullname,
1258                            filename,
1259                            object_name_len, object_name,
1260                            fullname,
1261                            object_name_len, object_name,
1262                            filename);
1263                }
1264                die("Path '%s' does not exist in '%.*s'",
1265                    filename, object_name_len, object_name);
1266        }
1267}
1268
1269/* Must be called only when :stage:filename doesn't exist. */
1270static void diagnose_invalid_index_path(int stage,
1271                                        const char *prefix,
1272                                        const char *filename)
1273{
1274        const struct cache_entry *ce;
1275        int pos;
1276        unsigned namelen = strlen(filename);
1277        unsigned fullnamelen;
1278        char *fullname;
1279
1280        if (!prefix)
1281                prefix = "";
1282
1283        /* Wrong stage number? */
1284        pos = cache_name_pos(filename, namelen);
1285        if (pos < 0)
1286                pos = -pos - 1;
1287        if (pos < active_nr) {
1288                ce = active_cache[pos];
1289                if (ce_namelen(ce) == namelen &&
1290                    !memcmp(ce->name, filename, namelen))
1291                        die("Path '%s' is in the index, but not at stage %d.\n"
1292                            "Did you mean ':%d:%s'?",
1293                            filename, stage,
1294                            ce_stage(ce), filename);
1295        }
1296
1297        /* Confusion between relative and absolute filenames? */
1298        fullnamelen = namelen + strlen(prefix);
1299        fullname = xmalloc(fullnamelen + 1);
1300        strcpy(fullname, prefix);
1301        strcat(fullname, filename);
1302        pos = cache_name_pos(fullname, fullnamelen);
1303        if (pos < 0)
1304                pos = -pos - 1;
1305        if (pos < active_nr) {
1306                ce = active_cache[pos];
1307                if (ce_namelen(ce) == fullnamelen &&
1308                    !memcmp(ce->name, fullname, fullnamelen))
1309                        die("Path '%s' is in the index, but not '%s'.\n"
1310                            "Did you mean ':%d:%s' aka ':%d:./%s'?",
1311                            fullname, filename,
1312                            ce_stage(ce), fullname,
1313                            ce_stage(ce), filename);
1314        }
1315
1316        if (file_exists(filename))
1317                die("Path '%s' exists on disk, but not in the index.", filename);
1318        if (errno == ENOENT || errno == ENOTDIR)
1319                die("Path '%s' does not exist (neither on disk nor in the index).",
1320                    filename);
1321
1322        free(fullname);
1323}
1324
1325
1326static char *resolve_relative_path(const char *rel)
1327{
1328        if (!starts_with(rel, "./") && !starts_with(rel, "../"))
1329                return NULL;
1330
1331        if (!startup_info)
1332                die("BUG: startup_info struct is not initialized.");
1333
1334        if (!is_inside_work_tree())
1335                die("relative path syntax can't be used outside working tree.");
1336
1337        /* die() inside prefix_path() if resolved path is outside worktree */
1338        return prefix_path(startup_info->prefix,
1339                           startup_info->prefix ? strlen(startup_info->prefix) : 0,
1340                           rel);
1341}
1342
1343static int get_sha1_with_context_1(const char *name,
1344                                   unsigned flags,
1345                                   const char *prefix,
1346                                   unsigned char *sha1,
1347                                   struct object_context *oc)
1348{
1349        int ret, bracket_depth;
1350        int namelen = strlen(name);
1351        const char *cp;
1352        int only_to_die = flags & GET_SHA1_ONLY_TO_DIE;
1353
1354        memset(oc, 0, sizeof(*oc));
1355        oc->mode = S_IFINVALID;
1356        ret = get_sha1_1(name, namelen, sha1, flags);
1357        if (!ret)
1358                return ret;
1359        /*
1360         * sha1:path --> object name of path in ent sha1
1361         * :path -> object name of absolute path in index
1362         * :./path -> object name of path relative to cwd in index
1363         * :[0-3]:path -> object name of path in index at stage
1364         * :/foo -> recent commit matching foo
1365         */
1366        if (name[0] == ':') {
1367                int stage = 0;
1368                const struct cache_entry *ce;
1369                char *new_path = NULL;
1370                int pos;
1371                if (!only_to_die && namelen > 2 && name[1] == '/') {
1372                        struct commit_list *list = NULL;
1373                        for_each_ref(handle_one_ref, &list);
1374                        commit_list_sort_by_date(&list);
1375                        return get_sha1_oneline(name + 2, sha1, list);
1376                }
1377                if (namelen < 3 ||
1378                    name[2] != ':' ||
1379                    name[1] < '0' || '3' < name[1])
1380                        cp = name + 1;
1381                else {
1382                        stage = name[1] - '0';
1383                        cp = name + 3;
1384                }
1385                new_path = resolve_relative_path(cp);
1386                if (!new_path) {
1387                        namelen = namelen - (cp - name);
1388                } else {
1389                        cp = new_path;
1390                        namelen = strlen(cp);
1391                }
1392
1393                strlcpy(oc->path, cp, sizeof(oc->path));
1394
1395                if (!active_cache)
1396                        read_cache();
1397                pos = cache_name_pos(cp, namelen);
1398                if (pos < 0)
1399                        pos = -pos - 1;
1400                while (pos < active_nr) {
1401                        ce = active_cache[pos];
1402                        if (ce_namelen(ce) != namelen ||
1403                            memcmp(ce->name, cp, namelen))
1404                                break;
1405                        if (ce_stage(ce) == stage) {
1406                                hashcpy(sha1, ce->sha1);
1407                                oc->mode = ce->ce_mode;
1408                                free(new_path);
1409                                return 0;
1410                        }
1411                        pos++;
1412                }
1413                if (only_to_die && name[1] && name[1] != '/')
1414                        diagnose_invalid_index_path(stage, prefix, cp);
1415                free(new_path);
1416                return -1;
1417        }
1418        for (cp = name, bracket_depth = 0; *cp; cp++) {
1419                if (*cp == '{')
1420                        bracket_depth++;
1421                else if (bracket_depth && *cp == '}')
1422                        bracket_depth--;
1423                else if (!bracket_depth && *cp == ':')
1424                        break;
1425        }
1426        if (*cp == ':') {
1427                unsigned char tree_sha1[20];
1428                int len = cp - name;
1429                if (!get_sha1_1(name, len, tree_sha1, GET_SHA1_TREEISH)) {
1430                        const char *filename = cp+1;
1431                        char *new_filename = NULL;
1432
1433                        new_filename = resolve_relative_path(filename);
1434                        if (new_filename)
1435                                filename = new_filename;
1436                        ret = get_tree_entry(tree_sha1, filename, sha1, &oc->mode);
1437                        if (ret && only_to_die) {
1438                                diagnose_invalid_sha1_path(prefix, filename,
1439                                                           tree_sha1,
1440                                                           name, len);
1441                        }
1442                        hashcpy(oc->tree, tree_sha1);
1443                        strlcpy(oc->path, filename, sizeof(oc->path));
1444
1445                        free(new_filename);
1446                        return ret;
1447                } else {
1448                        if (only_to_die)
1449                                die("Invalid object name '%.*s'.", len, name);
1450                }
1451        }
1452        return ret;
1453}
1454
1455/*
1456 * Call this function when you know "name" given by the end user must
1457 * name an object but it doesn't; the function _may_ die with a better
1458 * diagnostic message than "no such object 'name'", e.g. "Path 'doc' does not
1459 * exist in 'HEAD'" when given "HEAD:doc", or it may return in which case
1460 * you have a chance to diagnose the error further.
1461 */
1462void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
1463{
1464        struct object_context oc;
1465        unsigned char sha1[20];
1466        get_sha1_with_context_1(name, GET_SHA1_ONLY_TO_DIE, prefix, sha1, &oc);
1467}
1468
1469int get_sha1_with_context(const char *str, unsigned flags, unsigned char *sha1, struct object_context *orc)
1470{
1471        return get_sha1_with_context_1(str, flags, NULL, sha1, orc);
1472}