sha1_name.con commit Merge branch 'jk/doc-read-tree-table-asciidoctor-fix' into maint (e1a05be)
   1#include "cache.h"
   2#include "config.h"
   3#include "tag.h"
   4#include "commit.h"
   5#include "tree.h"
   6#include "blob.h"
   7#include "tree-walk.h"
   8#include "refs.h"
   9#include "remote.h"
  10#include "dir.h"
  11#include "sha1-array.h"
  12
  13static int get_sha1_oneline(const char *, unsigned char *, struct commit_list *);
  14
  15typedef int (*disambiguate_hint_fn)(const struct object_id *, void *);
  16
  17struct disambiguate_state {
  18        int len; /* length of prefix in hex chars */
  19        char hex_pfx[GIT_MAX_HEXSZ + 1];
  20        struct object_id bin_pfx;
  21
  22        disambiguate_hint_fn fn;
  23        void *cb_data;
  24        struct object_id candidate;
  25        unsigned candidate_exists:1;
  26        unsigned candidate_checked:1;
  27        unsigned candidate_ok:1;
  28        unsigned disambiguate_fn_used:1;
  29        unsigned ambiguous:1;
  30        unsigned always_call_fn:1;
  31};
  32
  33static void update_candidates(struct disambiguate_state *ds, const struct object_id *current)
  34{
  35        if (ds->always_call_fn) {
  36                ds->ambiguous = ds->fn(current, ds->cb_data) ? 1 : 0;
  37                return;
  38        }
  39        if (!ds->candidate_exists) {
  40                /* this is the first candidate */
  41                oidcpy(&ds->candidate, current);
  42                ds->candidate_exists = 1;
  43                return;
  44        } else if (!oidcmp(&ds->candidate, current)) {
  45                /* the same as what we already have seen */
  46                return;
  47        }
  48
  49        if (!ds->fn) {
  50                /* cannot disambiguate between ds->candidate and current */
  51                ds->ambiguous = 1;
  52                return;
  53        }
  54
  55        if (!ds->candidate_checked) {
  56                ds->candidate_ok = ds->fn(&ds->candidate, ds->cb_data);
  57                ds->disambiguate_fn_used = 1;
  58                ds->candidate_checked = 1;
  59        }
  60
  61        if (!ds->candidate_ok) {
  62                /* discard the candidate; we know it does not satisfy fn */
  63                oidcpy(&ds->candidate, current);
  64                ds->candidate_checked = 0;
  65                return;
  66        }
  67
  68        /* if we reach this point, we know ds->candidate satisfies fn */
  69        if (ds->fn(current, ds->cb_data)) {
  70                /*
  71                 * if both current and candidate satisfy fn, we cannot
  72                 * disambiguate.
  73                 */
  74                ds->candidate_ok = 0;
  75                ds->ambiguous = 1;
  76        }
  77
  78        /* otherwise, current can be discarded and candidate is still good */
  79}
  80
  81static int append_loose_object(const struct object_id *oid, const char *path,
  82                               void *data)
  83{
  84        oid_array_append(data, oid);
  85        return 0;
  86}
  87
  88static int match_sha(unsigned, const unsigned char *, const unsigned char *);
  89
  90static void find_short_object_filename(struct disambiguate_state *ds)
  91{
  92        int subdir_nr = ds->bin_pfx.hash[0];
  93        struct alternate_object_database *alt;
  94        static struct alternate_object_database *fakeent;
  95
  96        if (!fakeent) {
  97                /*
  98                 * Create a "fake" alternate object database that
  99                 * points to our own object database, to make it
 100                 * easier to get a temporary working space in
 101                 * alt->name/alt->base while iterating over the
 102                 * object databases including our own.
 103                 */
 104                fakeent = alloc_alt_odb(get_object_directory());
 105        }
 106        fakeent->next = alt_odb_list;
 107
 108        for (alt = fakeent; alt && !ds->ambiguous; alt = alt->next) {
 109                int pos;
 110
 111                if (!alt->loose_objects_subdir_seen[subdir_nr]) {
 112                        struct strbuf *buf = alt_scratch_buf(alt);
 113                        for_each_file_in_obj_subdir(subdir_nr, buf,
 114                                                    append_loose_object,
 115                                                    NULL, NULL,
 116                                                    &alt->loose_objects_cache);
 117                        alt->loose_objects_subdir_seen[subdir_nr] = 1;
 118                }
 119
 120                pos = oid_array_lookup(&alt->loose_objects_cache, &ds->bin_pfx);
 121                if (pos < 0)
 122                        pos = -1 - pos;
 123                while (!ds->ambiguous && pos < alt->loose_objects_cache.nr) {
 124                        const struct object_id *oid;
 125                        oid = alt->loose_objects_cache.oid + pos;
 126                        if (!match_sha(ds->len, ds->bin_pfx.hash, oid->hash))
 127                                break;
 128                        update_candidates(ds, oid);
 129                        pos++;
 130                }
 131        }
 132}
 133
 134static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
 135{
 136        do {
 137                if (*a != *b)
 138                        return 0;
 139                a++;
 140                b++;
 141                len -= 2;
 142        } while (len > 1);
 143        if (len)
 144                if ((*a ^ *b) & 0xf0)
 145                        return 0;
 146        return 1;
 147}
 148
 149static void unique_in_pack(struct packed_git *p,
 150                           struct disambiguate_state *ds)
 151{
 152        uint32_t num, last, i, first = 0;
 153        const struct object_id *current = NULL;
 154
 155        open_pack_index(p);
 156        num = p->num_objects;
 157        last = num;
 158        while (first < last) {
 159                uint32_t mid = (first + last) / 2;
 160                const unsigned char *current;
 161                int cmp;
 162
 163                current = nth_packed_object_sha1(p, mid);
 164                cmp = hashcmp(ds->bin_pfx.hash, current);
 165                if (!cmp) {
 166                        first = mid;
 167                        break;
 168                }
 169                if (cmp > 0) {
 170                        first = mid+1;
 171                        continue;
 172                }
 173                last = mid;
 174        }
 175
 176        /*
 177         * At this point, "first" is the location of the lowest object
 178         * with an object name that could match "bin_pfx".  See if we have
 179         * 0, 1 or more objects that actually match(es).
 180         */
 181        for (i = first; i < num && !ds->ambiguous; i++) {
 182                struct object_id oid;
 183                current = nth_packed_object_oid(&oid, p, i);
 184                if (!match_sha(ds->len, ds->bin_pfx.hash, current->hash))
 185                        break;
 186                update_candidates(ds, current);
 187        }
 188}
 189
 190static void find_short_packed_object(struct disambiguate_state *ds)
 191{
 192        struct packed_git *p;
 193
 194        prepare_packed_git();
 195        for (p = packed_git; p && !ds->ambiguous; p = p->next)
 196                unique_in_pack(p, ds);
 197}
 198
 199#define SHORT_NAME_NOT_FOUND (-1)
 200#define SHORT_NAME_AMBIGUOUS (-2)
 201
 202static int finish_object_disambiguation(struct disambiguate_state *ds,
 203                                        unsigned char *sha1)
 204{
 205        if (ds->ambiguous)
 206                return SHORT_NAME_AMBIGUOUS;
 207
 208        if (!ds->candidate_exists)
 209                return SHORT_NAME_NOT_FOUND;
 210
 211        if (!ds->candidate_checked)
 212                /*
 213                 * If this is the only candidate, there is no point
 214                 * calling the disambiguation hint callback.
 215                 *
 216                 * On the other hand, if the current candidate
 217                 * replaced an earlier candidate that did _not_ pass
 218                 * the disambiguation hint callback, then we do have
 219                 * more than one objects that match the short name
 220                 * given, so we should make sure this one matches;
 221                 * otherwise, if we discovered this one and the one
 222                 * that we previously discarded in the reverse order,
 223                 * we would end up showing different results in the
 224                 * same repository!
 225                 */
 226                ds->candidate_ok = (!ds->disambiguate_fn_used ||
 227                                    ds->fn(&ds->candidate, ds->cb_data));
 228
 229        if (!ds->candidate_ok)
 230                return SHORT_NAME_AMBIGUOUS;
 231
 232        hashcpy(sha1, ds->candidate.hash);
 233        return 0;
 234}
 235
 236static int disambiguate_commit_only(const struct object_id *oid, void *cb_data_unused)
 237{
 238        int kind = sha1_object_info(oid->hash, NULL);
 239        return kind == OBJ_COMMIT;
 240}
 241
 242static int disambiguate_committish_only(const struct object_id *oid, void *cb_data_unused)
 243{
 244        struct object *obj;
 245        int kind;
 246
 247        kind = sha1_object_info(oid->hash, NULL);
 248        if (kind == OBJ_COMMIT)
 249                return 1;
 250        if (kind != OBJ_TAG)
 251                return 0;
 252
 253        /* We need to do this the hard way... */
 254        obj = deref_tag(parse_object(oid), NULL, 0);
 255        if (obj && obj->type == OBJ_COMMIT)
 256                return 1;
 257        return 0;
 258}
 259
 260static int disambiguate_tree_only(const struct object_id *oid, void *cb_data_unused)
 261{
 262        int kind = sha1_object_info(oid->hash, NULL);
 263        return kind == OBJ_TREE;
 264}
 265
 266static int disambiguate_treeish_only(const struct object_id *oid, void *cb_data_unused)
 267{
 268        struct object *obj;
 269        int kind;
 270
 271        kind = sha1_object_info(oid->hash, NULL);
 272        if (kind == OBJ_TREE || kind == OBJ_COMMIT)
 273                return 1;
 274        if (kind != OBJ_TAG)
 275                return 0;
 276
 277        /* We need to do this the hard way... */
 278        obj = deref_tag(parse_object(oid), NULL, 0);
 279        if (obj && (obj->type == OBJ_TREE || obj->type == OBJ_COMMIT))
 280                return 1;
 281        return 0;
 282}
 283
 284static int disambiguate_blob_only(const struct object_id *oid, void *cb_data_unused)
 285{
 286        int kind = sha1_object_info(oid->hash, NULL);
 287        return kind == OBJ_BLOB;
 288}
 289
 290static disambiguate_hint_fn default_disambiguate_hint;
 291
 292int set_disambiguate_hint_config(const char *var, const char *value)
 293{
 294        static const struct {
 295                const char *name;
 296                disambiguate_hint_fn fn;
 297        } hints[] = {
 298                { "none", NULL },
 299                { "commit", disambiguate_commit_only },
 300                { "committish", disambiguate_committish_only },
 301                { "tree", disambiguate_tree_only },
 302                { "treeish", disambiguate_treeish_only },
 303                { "blob", disambiguate_blob_only }
 304        };
 305        int i;
 306
 307        if (!value)
 308                return config_error_nonbool(var);
 309
 310        for (i = 0; i < ARRAY_SIZE(hints); i++) {
 311                if (!strcasecmp(value, hints[i].name)) {
 312                        default_disambiguate_hint = hints[i].fn;
 313                        return 0;
 314                }
 315        }
 316
 317        return error("unknown hint type for '%s': %s", var, value);
 318}
 319
 320static int init_object_disambiguation(const char *name, int len,
 321                                      struct disambiguate_state *ds)
 322{
 323        int i;
 324
 325        if (len < MINIMUM_ABBREV || len > GIT_SHA1_HEXSZ)
 326                return -1;
 327
 328        memset(ds, 0, sizeof(*ds));
 329
 330        for (i = 0; i < len ;i++) {
 331                unsigned char c = name[i];
 332                unsigned char val;
 333                if (c >= '0' && c <= '9')
 334                        val = c - '0';
 335                else if (c >= 'a' && c <= 'f')
 336                        val = c - 'a' + 10;
 337                else if (c >= 'A' && c <='F') {
 338                        val = c - 'A' + 10;
 339                        c -= 'A' - 'a';
 340                }
 341                else
 342                        return -1;
 343                ds->hex_pfx[i] = c;
 344                if (!(i & 1))
 345                        val <<= 4;
 346                ds->bin_pfx.hash[i >> 1] |= val;
 347        }
 348
 349        ds->len = len;
 350        ds->hex_pfx[len] = '\0';
 351        prepare_alt_odb();
 352        return 0;
 353}
 354
 355static int show_ambiguous_object(const struct object_id *oid, void *data)
 356{
 357        const struct disambiguate_state *ds = data;
 358        struct strbuf desc = STRBUF_INIT;
 359        int type;
 360
 361
 362        if (ds->fn && !ds->fn(oid, ds->cb_data))
 363                return 0;
 364
 365        type = sha1_object_info(oid->hash, NULL);
 366        if (type == OBJ_COMMIT) {
 367                struct commit *commit = lookup_commit(oid);
 368                if (commit) {
 369                        struct pretty_print_context pp = {0};
 370                        pp.date_mode.type = DATE_SHORT;
 371                        format_commit_message(commit, " %ad - %s", &desc, &pp);
 372                }
 373        } else if (type == OBJ_TAG) {
 374                struct tag *tag = lookup_tag(oid);
 375                if (!parse_tag(tag) && tag->tag)
 376                        strbuf_addf(&desc, " %s", tag->tag);
 377        }
 378
 379        advise("  %s %s%s",
 380               find_unique_abbrev(oid->hash, DEFAULT_ABBREV),
 381               typename(type) ? typename(type) : "unknown type",
 382               desc.buf);
 383
 384        strbuf_release(&desc);
 385        return 0;
 386}
 387
 388static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 389                          unsigned flags)
 390{
 391        int status;
 392        struct disambiguate_state ds;
 393        int quietly = !!(flags & GET_SHA1_QUIETLY);
 394
 395        if (init_object_disambiguation(name, len, &ds) < 0)
 396                return -1;
 397
 398        if (HAS_MULTI_BITS(flags & GET_SHA1_DISAMBIGUATORS))
 399                die("BUG: multiple get_short_sha1 disambiguator flags");
 400
 401        if (flags & GET_SHA1_COMMIT)
 402                ds.fn = disambiguate_commit_only;
 403        else if (flags & GET_SHA1_COMMITTISH)
 404                ds.fn = disambiguate_committish_only;
 405        else if (flags & GET_SHA1_TREE)
 406                ds.fn = disambiguate_tree_only;
 407        else if (flags & GET_SHA1_TREEISH)
 408                ds.fn = disambiguate_treeish_only;
 409        else if (flags & GET_SHA1_BLOB)
 410                ds.fn = disambiguate_blob_only;
 411        else
 412                ds.fn = default_disambiguate_hint;
 413
 414        find_short_object_filename(&ds);
 415        find_short_packed_object(&ds);
 416        status = finish_object_disambiguation(&ds, sha1);
 417
 418        if (!quietly && (status == SHORT_NAME_AMBIGUOUS)) {
 419                error(_("short SHA1 %s is ambiguous"), ds.hex_pfx);
 420
 421                /*
 422                 * We may still have ambiguity if we simply saw a series of
 423                 * candidates that did not satisfy our hint function. In
 424                 * that case, we still want to show them, so disable the hint
 425                 * function entirely.
 426                 */
 427                if (!ds.ambiguous)
 428                        ds.fn = NULL;
 429
 430                advise(_("The candidates are:"));
 431                for_each_abbrev(ds.hex_pfx, show_ambiguous_object, &ds);
 432        }
 433
 434        return status;
 435}
 436
 437static int collect_ambiguous(const struct object_id *oid, void *data)
 438{
 439        oid_array_append(data, oid);
 440        return 0;
 441}
 442
 443int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
 444{
 445        struct oid_array collect = OID_ARRAY_INIT;
 446        struct disambiguate_state ds;
 447        int ret;
 448
 449        if (init_object_disambiguation(prefix, strlen(prefix), &ds) < 0)
 450                return -1;
 451
 452        ds.always_call_fn = 1;
 453        ds.fn = collect_ambiguous;
 454        ds.cb_data = &collect;
 455        find_short_object_filename(&ds);
 456        find_short_packed_object(&ds);
 457
 458        ret = oid_array_for_each_unique(&collect, fn, cb_data);
 459        oid_array_clear(&collect);
 460        return ret;
 461}
 462
 463/*
 464 * Return the slot of the most-significant bit set in "val". There are various
 465 * ways to do this quickly with fls() or __builtin_clzl(), but speed is
 466 * probably not a big deal here.
 467 */
 468static unsigned msb(unsigned long val)
 469{
 470        unsigned r = 0;
 471        while (val >>= 1)
 472                r++;
 473        return r;
 474}
 475
 476int find_unique_abbrev_r(char *hex, const unsigned char *sha1, int len)
 477{
 478        int status, exists;
 479
 480        if (len < 0) {
 481                unsigned long count = approximate_object_count();
 482                /*
 483                 * Add one because the MSB only tells us the highest bit set,
 484                 * not including the value of all the _other_ bits (so "15"
 485                 * is only one off of 2^4, but the MSB is the 3rd bit.
 486                 */
 487                len = msb(count) + 1;
 488                /*
 489                 * We now know we have on the order of 2^len objects, which
 490                 * expects a collision at 2^(len/2). But we also care about hex
 491                 * chars, not bits, and there are 4 bits per hex. So all
 492                 * together we need to divide by 2 and round up.
 493                 */
 494                len = DIV_ROUND_UP(len, 2);
 495                /*
 496                 * For very small repos, we stick with our regular fallback.
 497                 */
 498                if (len < FALLBACK_DEFAULT_ABBREV)
 499                        len = FALLBACK_DEFAULT_ABBREV;
 500        }
 501
 502        sha1_to_hex_r(hex, sha1);
 503        if (len == 40 || !len)
 504                return 40;
 505        exists = has_sha1_file(sha1);
 506        while (len < 40) {
 507                unsigned char sha1_ret[20];
 508                status = get_short_sha1(hex, len, sha1_ret, GET_SHA1_QUIETLY);
 509                if (exists
 510                    ? !status
 511                    : status == SHORT_NAME_NOT_FOUND) {
 512                        hex[len] = 0;
 513                        return len;
 514                }
 515                len++;
 516        }
 517        return len;
 518}
 519
 520const char *find_unique_abbrev(const unsigned char *sha1, int len)
 521{
 522        static int bufno;
 523        static char hexbuffer[4][GIT_MAX_HEXSZ + 1];
 524        char *hex = hexbuffer[bufno];
 525        bufno = (bufno + 1) % ARRAY_SIZE(hexbuffer);
 526        find_unique_abbrev_r(hex, sha1, len);
 527        return hex;
 528}
 529
 530static int ambiguous_path(const char *path, int len)
 531{
 532        int slash = 1;
 533        int cnt;
 534
 535        for (cnt = 0; cnt < len; cnt++) {
 536                switch (*path++) {
 537                case '\0':
 538                        break;
 539                case '/':
 540                        if (slash)
 541                                break;
 542                        slash = 1;
 543                        continue;
 544                case '.':
 545                        continue;
 546                default:
 547                        slash = 0;
 548                        continue;
 549                }
 550                break;
 551        }
 552        return slash;
 553}
 554
 555static inline int at_mark(const char *string, int len,
 556                          const char **suffix, int nr)
 557{
 558        int i;
 559
 560        for (i = 0; i < nr; i++) {
 561                int suffix_len = strlen(suffix[i]);
 562                if (suffix_len <= len
 563                    && !strncasecmp(string, suffix[i], suffix_len))
 564                        return suffix_len;
 565        }
 566        return 0;
 567}
 568
 569static inline int upstream_mark(const char *string, int len)
 570{
 571        const char *suffix[] = { "@{upstream}", "@{u}" };
 572        return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
 573}
 574
 575static inline int push_mark(const char *string, int len)
 576{
 577        const char *suffix[] = { "@{push}" };
 578        return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
 579}
 580
 581static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags);
 582static int interpret_nth_prior_checkout(const char *name, int namelen, struct strbuf *buf);
 583
 584static int get_sha1_basic(const char *str, int len, unsigned char *sha1,
 585                          unsigned int flags)
 586{
 587        static const char *warn_msg = "refname '%.*s' is ambiguous.";
 588        static const char *object_name_msg = N_(
 589        "Git normally never creates a ref that ends with 40 hex characters\n"
 590        "because it will be ignored when you just specify 40-hex. These refs\n"
 591        "may be created by mistake. For example,\n"
 592        "\n"
 593        "  git checkout -b $br $(git rev-parse ...)\n"
 594        "\n"
 595        "where \"$br\" is somehow empty and a 40-hex ref is created. Please\n"
 596        "examine these refs and maybe delete them. Turn this message off by\n"
 597        "running \"git config advice.objectNameWarning false\"");
 598        unsigned char tmp_sha1[20];
 599        char *real_ref = NULL;
 600        int refs_found = 0;
 601        int at, reflog_len, nth_prior = 0;
 602
 603        if (len == 40 && !get_sha1_hex(str, sha1)) {
 604                if (warn_ambiguous_refs && warn_on_object_refname_ambiguity) {
 605                        refs_found = dwim_ref(str, len, tmp_sha1, &real_ref);
 606                        if (refs_found > 0) {
 607                                warning(warn_msg, len, str);
 608                                if (advice_object_name_warning)
 609                                        fprintf(stderr, "%s\n", _(object_name_msg));
 610                        }
 611                        free(real_ref);
 612                }
 613                return 0;
 614        }
 615
 616        /* basic@{time or number or -number} format to query ref-log */
 617        reflog_len = at = 0;
 618        if (len && str[len-1] == '}') {
 619                for (at = len-4; at >= 0; at--) {
 620                        if (str[at] == '@' && str[at+1] == '{') {
 621                                if (str[at+2] == '-') {
 622                                        if (at != 0)
 623                                                /* @{-N} not at start */
 624                                                return -1;
 625                                        nth_prior = 1;
 626                                        continue;
 627                                }
 628                                if (!upstream_mark(str + at, len - at) &&
 629                                    !push_mark(str + at, len - at)) {
 630                                        reflog_len = (len-1) - (at+2);
 631                                        len = at;
 632                                }
 633                                break;
 634                        }
 635                }
 636        }
 637
 638        /* Accept only unambiguous ref paths. */
 639        if (len && ambiguous_path(str, len))
 640                return -1;
 641
 642        if (nth_prior) {
 643                struct strbuf buf = STRBUF_INIT;
 644                int detached;
 645
 646                if (interpret_nth_prior_checkout(str, len, &buf) > 0) {
 647                        detached = (buf.len == 40 && !get_sha1_hex(buf.buf, sha1));
 648                        strbuf_release(&buf);
 649                        if (detached)
 650                                return 0;
 651                }
 652        }
 653
 654        if (!len && reflog_len)
 655                /* allow "@{...}" to mean the current branch reflog */
 656                refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
 657        else if (reflog_len)
 658                refs_found = dwim_log(str, len, sha1, &real_ref);
 659        else
 660                refs_found = dwim_ref(str, len, sha1, &real_ref);
 661
 662        if (!refs_found)
 663                return -1;
 664
 665        if (warn_ambiguous_refs && !(flags & GET_SHA1_QUIETLY) &&
 666            (refs_found > 1 ||
 667             !get_short_sha1(str, len, tmp_sha1, GET_SHA1_QUIETLY)))
 668                warning(warn_msg, len, str);
 669
 670        if (reflog_len) {
 671                int nth, i;
 672                timestamp_t at_time;
 673                timestamp_t co_time;
 674                int co_tz, co_cnt;
 675
 676                /* Is it asking for N-th entry, or approxidate? */
 677                for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 678                        char ch = str[at+2+i];
 679                        if ('0' <= ch && ch <= '9')
 680                                nth = nth * 10 + ch - '0';
 681                        else
 682                                nth = -1;
 683                }
 684                if (100000000 <= nth) {
 685                        at_time = nth;
 686                        nth = -1;
 687                } else if (0 <= nth)
 688                        at_time = 0;
 689                else {
 690                        int errors = 0;
 691                        char *tmp = xstrndup(str + at + 2, reflog_len);
 692                        at_time = approxidate_careful(tmp, &errors);
 693                        free(tmp);
 694                        if (errors) {
 695                                free(real_ref);
 696                                return -1;
 697                        }
 698                }
 699                if (read_ref_at(real_ref, flags, at_time, nth, sha1, NULL,
 700                                &co_time, &co_tz, &co_cnt)) {
 701                        if (!len) {
 702                                if (starts_with(real_ref, "refs/heads/")) {
 703                                        str = real_ref + 11;
 704                                        len = strlen(real_ref + 11);
 705                                } else {
 706                                        /* detached HEAD */
 707                                        str = "HEAD";
 708                                        len = 4;
 709                                }
 710                        }
 711                        if (at_time) {
 712                                if (!(flags & GET_SHA1_QUIETLY)) {
 713                                        warning("Log for '%.*s' only goes "
 714                                                "back to %s.", len, str,
 715                                                show_date(co_time, co_tz, DATE_MODE(RFC2822)));
 716                                }
 717                        } else {
 718                                if (flags & GET_SHA1_QUIETLY) {
 719                                        exit(128);
 720                                }
 721                                die("Log for '%.*s' only has %d entries.",
 722                                    len, str, co_cnt);
 723                        }
 724                }
 725        }
 726
 727        free(real_ref);
 728        return 0;
 729}
 730
 731static int get_parent(const char *name, int len,
 732                      unsigned char *result, int idx)
 733{
 734        struct object_id oid;
 735        int ret = get_sha1_1(name, len, oid.hash, GET_SHA1_COMMITTISH);
 736        struct commit *commit;
 737        struct commit_list *p;
 738
 739        if (ret)
 740                return ret;
 741        commit = lookup_commit_reference(&oid);
 742        if (parse_commit(commit))
 743                return -1;
 744        if (!idx) {
 745                hashcpy(result, commit->object.oid.hash);
 746                return 0;
 747        }
 748        p = commit->parents;
 749        while (p) {
 750                if (!--idx) {
 751                        hashcpy(result, p->item->object.oid.hash);
 752                        return 0;
 753                }
 754                p = p->next;
 755        }
 756        return -1;
 757}
 758
 759static int get_nth_ancestor(const char *name, int len,
 760                            unsigned char *result, int generation)
 761{
 762        struct object_id oid;
 763        struct commit *commit;
 764        int ret;
 765
 766        ret = get_sha1_1(name, len, oid.hash, GET_SHA1_COMMITTISH);
 767        if (ret)
 768                return ret;
 769        commit = lookup_commit_reference(&oid);
 770        if (!commit)
 771                return -1;
 772
 773        while (generation--) {
 774                if (parse_commit(commit) || !commit->parents)
 775                        return -1;
 776                commit = commit->parents->item;
 777        }
 778        hashcpy(result, commit->object.oid.hash);
 779        return 0;
 780}
 781
 782struct object *peel_to_type(const char *name, int namelen,
 783                            struct object *o, enum object_type expected_type)
 784{
 785        if (name && !namelen)
 786                namelen = strlen(name);
 787        while (1) {
 788                if (!o || (!o->parsed && !parse_object(&o->oid)))
 789                        return NULL;
 790                if (expected_type == OBJ_ANY || o->type == expected_type)
 791                        return o;
 792                if (o->type == OBJ_TAG)
 793                        o = ((struct tag*) o)->tagged;
 794                else if (o->type == OBJ_COMMIT)
 795                        o = &(((struct commit *) o)->tree->object);
 796                else {
 797                        if (name)
 798                                error("%.*s: expected %s type, but the object "
 799                                      "dereferences to %s type",
 800                                      namelen, name, typename(expected_type),
 801                                      typename(o->type));
 802                        return NULL;
 803                }
 804        }
 805}
 806
 807static int peel_onion(const char *name, int len, unsigned char *sha1,
 808                      unsigned lookup_flags)
 809{
 810        struct object_id outer;
 811        const char *sp;
 812        unsigned int expected_type = 0;
 813        struct object *o;
 814
 815        /*
 816         * "ref^{type}" dereferences ref repeatedly until you cannot
 817         * dereference anymore, or you get an object of given type,
 818         * whichever comes first.  "ref^{}" means just dereference
 819         * tags until you get a non-tag.  "ref^0" is a shorthand for
 820         * "ref^{commit}".  "commit^{tree}" could be used to find the
 821         * top-level tree of the given commit.
 822         */
 823        if (len < 4 || name[len-1] != '}')
 824                return -1;
 825
 826        for (sp = name + len - 1; name <= sp; sp--) {
 827                int ch = *sp;
 828                if (ch == '{' && name < sp && sp[-1] == '^')
 829                        break;
 830        }
 831        if (sp <= name)
 832                return -1;
 833
 834        sp++; /* beginning of type name, or closing brace for empty */
 835        if (starts_with(sp, "commit}"))
 836                expected_type = OBJ_COMMIT;
 837        else if (starts_with(sp, "tag}"))
 838                expected_type = OBJ_TAG;
 839        else if (starts_with(sp, "tree}"))
 840                expected_type = OBJ_TREE;
 841        else if (starts_with(sp, "blob}"))
 842                expected_type = OBJ_BLOB;
 843        else if (starts_with(sp, "object}"))
 844                expected_type = OBJ_ANY;
 845        else if (sp[0] == '}')
 846                expected_type = OBJ_NONE;
 847        else if (sp[0] == '/')
 848                expected_type = OBJ_COMMIT;
 849        else
 850                return -1;
 851
 852        lookup_flags &= ~GET_SHA1_DISAMBIGUATORS;
 853        if (expected_type == OBJ_COMMIT)
 854                lookup_flags |= GET_SHA1_COMMITTISH;
 855        else if (expected_type == OBJ_TREE)
 856                lookup_flags |= GET_SHA1_TREEISH;
 857
 858        if (get_sha1_1(name, sp - name - 2, outer.hash, lookup_flags))
 859                return -1;
 860
 861        o = parse_object(&outer);
 862        if (!o)
 863                return -1;
 864        if (!expected_type) {
 865                o = deref_tag(o, name, sp - name - 2);
 866                if (!o || (!o->parsed && !parse_object(&o->oid)))
 867                        return -1;
 868                hashcpy(sha1, o->oid.hash);
 869                return 0;
 870        }
 871
 872        /*
 873         * At this point, the syntax look correct, so
 874         * if we do not get the needed object, we should
 875         * barf.
 876         */
 877        o = peel_to_type(name, len, o, expected_type);
 878        if (!o)
 879                return -1;
 880
 881        hashcpy(sha1, o->oid.hash);
 882        if (sp[0] == '/') {
 883                /* "$commit^{/foo}" */
 884                char *prefix;
 885                int ret;
 886                struct commit_list *list = NULL;
 887
 888                /*
 889                 * $commit^{/}. Some regex implementation may reject.
 890                 * We don't need regex anyway. '' pattern always matches.
 891                 */
 892                if (sp[1] == '}')
 893                        return 0;
 894
 895                prefix = xstrndup(sp + 1, name + len - 1 - (sp + 1));
 896                commit_list_insert((struct commit *)o, &list);
 897                ret = get_sha1_oneline(prefix, sha1, list);
 898                free(prefix);
 899                return ret;
 900        }
 901        return 0;
 902}
 903
 904static int get_describe_name(const char *name, int len, unsigned char *sha1)
 905{
 906        const char *cp;
 907        unsigned flags = GET_SHA1_QUIETLY | GET_SHA1_COMMIT;
 908
 909        for (cp = name + len - 1; name + 2 <= cp; cp--) {
 910                char ch = *cp;
 911                if (!isxdigit(ch)) {
 912                        /* We must be looking at g in "SOMETHING-g"
 913                         * for it to be describe output.
 914                         */
 915                        if (ch == 'g' && cp[-1] == '-') {
 916                                cp++;
 917                                len -= cp - name;
 918                                return get_short_sha1(cp, len, sha1, flags);
 919                        }
 920                }
 921        }
 922        return -1;
 923}
 924
 925static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags)
 926{
 927        int ret, has_suffix;
 928        const char *cp;
 929
 930        /*
 931         * "name~3" is "name^^^", "name~" is "name~1", and "name^" is "name^1".
 932         */
 933        has_suffix = 0;
 934        for (cp = name + len - 1; name <= cp; cp--) {
 935                int ch = *cp;
 936                if ('0' <= ch && ch <= '9')
 937                        continue;
 938                if (ch == '~' || ch == '^')
 939                        has_suffix = ch;
 940                break;
 941        }
 942
 943        if (has_suffix) {
 944                int num = 0;
 945                int len1 = cp - name;
 946                cp++;
 947                while (cp < name + len)
 948                        num = num * 10 + *cp++ - '0';
 949                if (!num && len1 == len - 1)
 950                        num = 1;
 951                if (has_suffix == '^')
 952                        return get_parent(name, len1, sha1, num);
 953                /* else if (has_suffix == '~') -- goes without saying */
 954                return get_nth_ancestor(name, len1, sha1, num);
 955        }
 956
 957        ret = peel_onion(name, len, sha1, lookup_flags);
 958        if (!ret)
 959                return 0;
 960
 961        ret = get_sha1_basic(name, len, sha1, lookup_flags);
 962        if (!ret)
 963                return 0;
 964
 965        /* It could be describe output that is "SOMETHING-gXXXX" */
 966        ret = get_describe_name(name, len, sha1);
 967        if (!ret)
 968                return 0;
 969
 970        return get_short_sha1(name, len, sha1, lookup_flags);
 971}
 972
 973/*
 974 * This interprets names like ':/Initial revision of "git"' by searching
 975 * through history and returning the first commit whose message starts
 976 * the given regular expression.
 977 *
 978 * For negative-matching, prefix the pattern-part with '!-', like: ':/!-WIP'.
 979 *
 980 * For a literal '!' character at the beginning of a pattern, you have to repeat
 981 * that, like: ':/!!foo'
 982 *
 983 * For future extension, all other sequences beginning with ':/!' are reserved.
 984 */
 985
 986/* Remember to update object flag allocation in object.h */
 987#define ONELINE_SEEN (1u<<20)
 988
 989static int handle_one_ref(const char *path, const struct object_id *oid,
 990                          int flag, void *cb_data)
 991{
 992        struct commit_list **list = cb_data;
 993        struct object *object = parse_object(oid);
 994        if (!object)
 995                return 0;
 996        if (object->type == OBJ_TAG) {
 997                object = deref_tag(object, path, strlen(path));
 998                if (!object)
 999                        return 0;
1000        }
1001        if (object->type != OBJ_COMMIT)
1002                return 0;
1003        commit_list_insert((struct commit *)object, list);
1004        return 0;
1005}
1006
1007static int get_sha1_oneline(const char *prefix, unsigned char *sha1,
1008                            struct commit_list *list)
1009{
1010        struct commit_list *backup = NULL, *l;
1011        int found = 0;
1012        int negative = 0;
1013        regex_t regex;
1014
1015        if (prefix[0] == '!') {
1016                prefix++;
1017
1018                if (prefix[0] == '-') {
1019                        prefix++;
1020                        negative = 1;
1021                } else if (prefix[0] != '!') {
1022                        return -1;
1023                }
1024        }
1025
1026        if (regcomp(&regex, prefix, REG_EXTENDED))
1027                return -1;
1028
1029        for (l = list; l; l = l->next) {
1030                l->item->object.flags |= ONELINE_SEEN;
1031                commit_list_insert(l->item, &backup);
1032        }
1033        while (list) {
1034                const char *p, *buf;
1035                struct commit *commit;
1036                int matches;
1037
1038                commit = pop_most_recent_commit(&list, ONELINE_SEEN);
1039                if (!parse_object(&commit->object.oid))
1040                        continue;
1041                buf = get_commit_buffer(commit, NULL);
1042                p = strstr(buf, "\n\n");
1043                matches = negative ^ (p && !regexec(&regex, p + 2, 0, NULL, 0));
1044                unuse_commit_buffer(commit, buf);
1045
1046                if (matches) {
1047                        hashcpy(sha1, commit->object.oid.hash);
1048                        found = 1;
1049                        break;
1050                }
1051        }
1052        regfree(&regex);
1053        free_commit_list(list);
1054        for (l = backup; l; l = l->next)
1055                clear_commit_marks(l->item, ONELINE_SEEN);
1056        free_commit_list(backup);
1057        return found ? 0 : -1;
1058}
1059
1060struct grab_nth_branch_switch_cbdata {
1061        int remaining;
1062        struct strbuf buf;
1063};
1064
1065static int grab_nth_branch_switch(struct object_id *ooid, struct object_id *noid,
1066                                  const char *email, timestamp_t timestamp, int tz,
1067                                  const char *message, void *cb_data)
1068{
1069        struct grab_nth_branch_switch_cbdata *cb = cb_data;
1070        const char *match = NULL, *target = NULL;
1071        size_t len;
1072
1073        if (skip_prefix(message, "checkout: moving from ", &match))
1074                target = strstr(match, " to ");
1075
1076        if (!match || !target)
1077                return 0;
1078        if (--(cb->remaining) == 0) {
1079                len = target - match;
1080                strbuf_reset(&cb->buf);
1081                strbuf_add(&cb->buf, match, len);
1082                return 1; /* we are done */
1083        }
1084        return 0;
1085}
1086
1087/*
1088 * Parse @{-N} syntax, return the number of characters parsed
1089 * if successful; otherwise signal an error with negative value.
1090 */
1091static int interpret_nth_prior_checkout(const char *name, int namelen,
1092                                        struct strbuf *buf)
1093{
1094        long nth;
1095        int retval;
1096        struct grab_nth_branch_switch_cbdata cb;
1097        const char *brace;
1098        char *num_end;
1099
1100        if (namelen < 4)
1101                return -1;
1102        if (name[0] != '@' || name[1] != '{' || name[2] != '-')
1103                return -1;
1104        brace = memchr(name, '}', namelen);
1105        if (!brace)
1106                return -1;
1107        nth = strtol(name + 3, &num_end, 10);
1108        if (num_end != brace)
1109                return -1;
1110        if (nth <= 0)
1111                return -1;
1112        cb.remaining = nth;
1113        strbuf_init(&cb.buf, 20);
1114
1115        retval = 0;
1116        if (0 < for_each_reflog_ent_reverse("HEAD", grab_nth_branch_switch, &cb)) {
1117                strbuf_reset(buf);
1118                strbuf_addbuf(buf, &cb.buf);
1119                retval = brace - name + 1;
1120        }
1121
1122        strbuf_release(&cb.buf);
1123        return retval;
1124}
1125
1126int get_oid_mb(const char *name, struct object_id *oid)
1127{
1128        struct commit *one, *two;
1129        struct commit_list *mbs;
1130        struct object_id oid_tmp;
1131        const char *dots;
1132        int st;
1133
1134        dots = strstr(name, "...");
1135        if (!dots)
1136                return get_oid(name, oid);
1137        if (dots == name)
1138                st = get_oid("HEAD", &oid_tmp);
1139        else {
1140                struct strbuf sb;
1141                strbuf_init(&sb, dots - name);
1142                strbuf_add(&sb, name, dots - name);
1143                st = get_sha1_committish(sb.buf, oid_tmp.hash);
1144                strbuf_release(&sb);
1145        }
1146        if (st)
1147                return st;
1148        one = lookup_commit_reference_gently(&oid_tmp, 0);
1149        if (!one)
1150                return -1;
1151
1152        if (get_sha1_committish(dots[3] ? (dots + 3) : "HEAD", oid_tmp.hash))
1153                return -1;
1154        two = lookup_commit_reference_gently(&oid_tmp, 0);
1155        if (!two)
1156                return -1;
1157        mbs = get_merge_bases(one, two);
1158        if (!mbs || mbs->next)
1159                st = -1;
1160        else {
1161                st = 0;
1162                oidcpy(oid, &mbs->item->object.oid);
1163        }
1164        free_commit_list(mbs);
1165        return st;
1166}
1167
1168/* parse @something syntax, when 'something' is not {.*} */
1169static int interpret_empty_at(const char *name, int namelen, int len, struct strbuf *buf)
1170{
1171        const char *next;
1172
1173        if (len || name[1] == '{')
1174                return -1;
1175
1176        /* make sure it's a single @, or @@{.*}, not @foo */
1177        next = memchr(name + len + 1, '@', namelen - len - 1);
1178        if (next && next[1] != '{')
1179                return -1;
1180        if (!next)
1181                next = name + namelen;
1182        if (next != name + 1)
1183                return -1;
1184
1185        strbuf_reset(buf);
1186        strbuf_add(buf, "HEAD", 4);
1187        return 1;
1188}
1189
1190static int reinterpret(const char *name, int namelen, int len,
1191                       struct strbuf *buf, unsigned allowed)
1192{
1193        /* we have extra data, which might need further processing */
1194        struct strbuf tmp = STRBUF_INIT;
1195        int used = buf->len;
1196        int ret;
1197
1198        strbuf_add(buf, name + len, namelen - len);
1199        ret = interpret_branch_name(buf->buf, buf->len, &tmp, allowed);
1200        /* that data was not interpreted, remove our cruft */
1201        if (ret < 0) {
1202                strbuf_setlen(buf, used);
1203                return len;
1204        }
1205        strbuf_reset(buf);
1206        strbuf_addbuf(buf, &tmp);
1207        strbuf_release(&tmp);
1208        /* tweak for size of {-N} versus expanded ref name */
1209        return ret - used + len;
1210}
1211
1212static void set_shortened_ref(struct strbuf *buf, const char *ref)
1213{
1214        char *s = shorten_unambiguous_ref(ref, 0);
1215        strbuf_reset(buf);
1216        strbuf_addstr(buf, s);
1217        free(s);
1218}
1219
1220static int branch_interpret_allowed(const char *refname, unsigned allowed)
1221{
1222        if (!allowed)
1223                return 1;
1224
1225        if ((allowed & INTERPRET_BRANCH_LOCAL) &&
1226            starts_with(refname, "refs/heads/"))
1227                return 1;
1228        if ((allowed & INTERPRET_BRANCH_REMOTE) &&
1229            starts_with(refname, "refs/remotes/"))
1230                return 1;
1231
1232        return 0;
1233}
1234
1235static int interpret_branch_mark(const char *name, int namelen,
1236                                 int at, struct strbuf *buf,
1237                                 int (*get_mark)(const char *, int),
1238                                 const char *(*get_data)(struct branch *,
1239                                                         struct strbuf *),
1240                                 unsigned allowed)
1241{
1242        int len;
1243        struct branch *branch;
1244        struct strbuf err = STRBUF_INIT;
1245        const char *value;
1246
1247        len = get_mark(name + at, namelen - at);
1248        if (!len)
1249                return -1;
1250
1251        if (memchr(name, ':', at))
1252                return -1;
1253
1254        if (at) {
1255                char *name_str = xmemdupz(name, at);
1256                branch = branch_get(name_str);
1257                free(name_str);
1258        } else
1259                branch = branch_get(NULL);
1260
1261        value = get_data(branch, &err);
1262        if (!value)
1263                die("%s", err.buf);
1264
1265        if (!branch_interpret_allowed(value, allowed))
1266                return -1;
1267
1268        set_shortened_ref(buf, value);
1269        return len + at;
1270}
1271
1272int interpret_branch_name(const char *name, int namelen, struct strbuf *buf,
1273                          unsigned allowed)
1274{
1275        char *at;
1276        const char *start;
1277        int len;
1278
1279        if (!namelen)
1280                namelen = strlen(name);
1281
1282        if (!allowed || (allowed & INTERPRET_BRANCH_LOCAL)) {
1283                len = interpret_nth_prior_checkout(name, namelen, buf);
1284                if (!len) {
1285                        return len; /* syntax Ok, not enough switches */
1286                } else if (len > 0) {
1287                        if (len == namelen)
1288                                return len; /* consumed all */
1289                        else
1290                                return reinterpret(name, namelen, len, buf, allowed);
1291                }
1292        }
1293
1294        for (start = name;
1295             (at = memchr(start, '@', namelen - (start - name)));
1296             start = at + 1) {
1297
1298                if (!allowed || (allowed & INTERPRET_BRANCH_HEAD)) {
1299                        len = interpret_empty_at(name, namelen, at - name, buf);
1300                        if (len > 0)
1301                                return reinterpret(name, namelen, len, buf,
1302                                                   allowed);
1303                }
1304
1305                len = interpret_branch_mark(name, namelen, at - name, buf,
1306                                            upstream_mark, branch_get_upstream,
1307                                            allowed);
1308                if (len > 0)
1309                        return len;
1310
1311                len = interpret_branch_mark(name, namelen, at - name, buf,
1312                                            push_mark, branch_get_push,
1313                                            allowed);
1314                if (len > 0)
1315                        return len;
1316        }
1317
1318        return -1;
1319}
1320
1321void strbuf_branchname(struct strbuf *sb, const char *name, unsigned allowed)
1322{
1323        int len = strlen(name);
1324        int used = interpret_branch_name(name, len, sb, allowed);
1325
1326        if (used < 0)
1327                used = 0;
1328        strbuf_add(sb, name + used, len - used);
1329}
1330
1331int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
1332{
1333        strbuf_branchname(sb, name, INTERPRET_BRANCH_LOCAL);
1334        if (name[0] == '-')
1335                return -1;
1336        strbuf_splice(sb, 0, 0, "refs/heads/", 11);
1337        return check_refname_format(sb->buf, 0);
1338}
1339
1340/*
1341 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
1342 * notably "xyz^" for "parent of xyz"
1343 */
1344int get_sha1(const char *name, unsigned char *sha1)
1345{
1346        struct object_context unused;
1347        return get_sha1_with_context(name, 0, sha1, &unused);
1348}
1349
1350/*
1351 * This is like "get_sha1()", but for struct object_id.
1352 */
1353int get_oid(const char *name, struct object_id *oid)
1354{
1355        return get_sha1(name, oid->hash);
1356}
1357
1358
1359/*
1360 * Many callers know that the user meant to name a commit-ish by
1361 * syntactical positions where the object name appears.  Calling this
1362 * function allows the machinery to disambiguate shorter-than-unique
1363 * abbreviated object names between commit-ish and others.
1364 *
1365 * Note that this does NOT error out when the named object is not a
1366 * commit-ish. It is merely to give a hint to the disambiguation
1367 * machinery.
1368 */
1369int get_sha1_committish(const char *name, unsigned char *sha1)
1370{
1371        struct object_context unused;
1372        return get_sha1_with_context(name, GET_SHA1_COMMITTISH,
1373                                     sha1, &unused);
1374}
1375
1376int get_sha1_treeish(const char *name, unsigned char *sha1)
1377{
1378        struct object_context unused;
1379        return get_sha1_with_context(name, GET_SHA1_TREEISH,
1380                                     sha1, &unused);
1381}
1382
1383int get_sha1_commit(const char *name, unsigned char *sha1)
1384{
1385        struct object_context unused;
1386        return get_sha1_with_context(name, GET_SHA1_COMMIT,
1387                                     sha1, &unused);
1388}
1389
1390int get_sha1_tree(const char *name, unsigned char *sha1)
1391{
1392        struct object_context unused;
1393        return get_sha1_with_context(name, GET_SHA1_TREE,
1394                                     sha1, &unused);
1395}
1396
1397int get_sha1_blob(const char *name, unsigned char *sha1)
1398{
1399        struct object_context unused;
1400        return get_sha1_with_context(name, GET_SHA1_BLOB,
1401                                     sha1, &unused);
1402}
1403
1404/* Must be called only when object_name:filename doesn't exist. */
1405static void diagnose_invalid_sha1_path(const char *prefix,
1406                                       const char *filename,
1407                                       const unsigned char *tree_sha1,
1408                                       const char *object_name,
1409                                       int object_name_len)
1410{
1411        unsigned char sha1[20];
1412        unsigned mode;
1413
1414        if (!prefix)
1415                prefix = "";
1416
1417        if (file_exists(filename))
1418                die("Path '%s' exists on disk, but not in '%.*s'.",
1419                    filename, object_name_len, object_name);
1420        if (is_missing_file_error(errno)) {
1421                char *fullname = xstrfmt("%s%s", prefix, filename);
1422
1423                if (!get_tree_entry(tree_sha1, fullname,
1424                                    sha1, &mode)) {
1425                        die("Path '%s' exists, but not '%s'.\n"
1426                            "Did you mean '%.*s:%s' aka '%.*s:./%s'?",
1427                            fullname,
1428                            filename,
1429                            object_name_len, object_name,
1430                            fullname,
1431                            object_name_len, object_name,
1432                            filename);
1433                }
1434                die("Path '%s' does not exist in '%.*s'",
1435                    filename, object_name_len, object_name);
1436        }
1437}
1438
1439/* Must be called only when :stage:filename doesn't exist. */
1440static void diagnose_invalid_index_path(int stage,
1441                                        const char *prefix,
1442                                        const char *filename)
1443{
1444        const struct cache_entry *ce;
1445        int pos;
1446        unsigned namelen = strlen(filename);
1447        struct strbuf fullname = STRBUF_INIT;
1448
1449        if (!prefix)
1450                prefix = "";
1451
1452        /* Wrong stage number? */
1453        pos = cache_name_pos(filename, namelen);
1454        if (pos < 0)
1455                pos = -pos - 1;
1456        if (pos < active_nr) {
1457                ce = active_cache[pos];
1458                if (ce_namelen(ce) == namelen &&
1459                    !memcmp(ce->name, filename, namelen))
1460                        die("Path '%s' is in the index, but not at stage %d.\n"
1461                            "Did you mean ':%d:%s'?",
1462                            filename, stage,
1463                            ce_stage(ce), filename);
1464        }
1465
1466        /* Confusion between relative and absolute filenames? */
1467        strbuf_addstr(&fullname, prefix);
1468        strbuf_addstr(&fullname, filename);
1469        pos = cache_name_pos(fullname.buf, fullname.len);
1470        if (pos < 0)
1471                pos = -pos - 1;
1472        if (pos < active_nr) {
1473                ce = active_cache[pos];
1474                if (ce_namelen(ce) == fullname.len &&
1475                    !memcmp(ce->name, fullname.buf, fullname.len))
1476                        die("Path '%s' is in the index, but not '%s'.\n"
1477                            "Did you mean ':%d:%s' aka ':%d:./%s'?",
1478                            fullname.buf, filename,
1479                            ce_stage(ce), fullname.buf,
1480                            ce_stage(ce), filename);
1481        }
1482
1483        if (file_exists(filename))
1484                die("Path '%s' exists on disk, but not in the index.", filename);
1485        if (is_missing_file_error(errno))
1486                die("Path '%s' does not exist (neither on disk nor in the index).",
1487                    filename);
1488
1489        strbuf_release(&fullname);
1490}
1491
1492
1493static char *resolve_relative_path(const char *rel)
1494{
1495        if (!starts_with(rel, "./") && !starts_with(rel, "../"))
1496                return NULL;
1497
1498        if (!is_inside_work_tree())
1499                die("relative path syntax can't be used outside working tree.");
1500
1501        /* die() inside prefix_path() if resolved path is outside worktree */
1502        return prefix_path(startup_info->prefix,
1503                           startup_info->prefix ? strlen(startup_info->prefix) : 0,
1504                           rel);
1505}
1506
1507static int get_sha1_with_context_1(const char *name,
1508                                   unsigned flags,
1509                                   const char *prefix,
1510                                   unsigned char *sha1,
1511                                   struct object_context *oc)
1512{
1513        int ret, bracket_depth;
1514        int namelen = strlen(name);
1515        const char *cp;
1516        int only_to_die = flags & GET_SHA1_ONLY_TO_DIE;
1517
1518        if (only_to_die)
1519                flags |= GET_SHA1_QUIETLY;
1520
1521        memset(oc, 0, sizeof(*oc));
1522        oc->mode = S_IFINVALID;
1523        strbuf_init(&oc->symlink_path, 0);
1524        ret = get_sha1_1(name, namelen, sha1, flags);
1525        if (!ret)
1526                return ret;
1527        /*
1528         * sha1:path --> object name of path in ent sha1
1529         * :path -> object name of absolute path in index
1530         * :./path -> object name of path relative to cwd in index
1531         * :[0-3]:path -> object name of path in index at stage
1532         * :/foo -> recent commit matching foo
1533         */
1534        if (name[0] == ':') {
1535                int stage = 0;
1536                const struct cache_entry *ce;
1537                char *new_path = NULL;
1538                int pos;
1539                if (!only_to_die && namelen > 2 && name[1] == '/') {
1540                        struct commit_list *list = NULL;
1541
1542                        for_each_ref(handle_one_ref, &list);
1543                        commit_list_sort_by_date(&list);
1544                        return get_sha1_oneline(name + 2, sha1, list);
1545                }
1546                if (namelen < 3 ||
1547                    name[2] != ':' ||
1548                    name[1] < '0' || '3' < name[1])
1549                        cp = name + 1;
1550                else {
1551                        stage = name[1] - '0';
1552                        cp = name + 3;
1553                }
1554                new_path = resolve_relative_path(cp);
1555                if (!new_path) {
1556                        namelen = namelen - (cp - name);
1557                } else {
1558                        cp = new_path;
1559                        namelen = strlen(cp);
1560                }
1561
1562                if (flags & GET_SHA1_RECORD_PATH)
1563                        oc->path = xstrdup(cp);
1564
1565                if (!active_cache)
1566                        read_cache();
1567                pos = cache_name_pos(cp, namelen);
1568                if (pos < 0)
1569                        pos = -pos - 1;
1570                while (pos < active_nr) {
1571                        ce = active_cache[pos];
1572                        if (ce_namelen(ce) != namelen ||
1573                            memcmp(ce->name, cp, namelen))
1574                                break;
1575                        if (ce_stage(ce) == stage) {
1576                                hashcpy(sha1, ce->oid.hash);
1577                                oc->mode = ce->ce_mode;
1578                                free(new_path);
1579                                return 0;
1580                        }
1581                        pos++;
1582                }
1583                if (only_to_die && name[1] && name[1] != '/')
1584                        diagnose_invalid_index_path(stage, prefix, cp);
1585                free(new_path);
1586                return -1;
1587        }
1588        for (cp = name, bracket_depth = 0; *cp; cp++) {
1589                if (*cp == '{')
1590                        bracket_depth++;
1591                else if (bracket_depth && *cp == '}')
1592                        bracket_depth--;
1593                else if (!bracket_depth && *cp == ':')
1594                        break;
1595        }
1596        if (*cp == ':') {
1597                unsigned char tree_sha1[20];
1598                int len = cp - name;
1599                unsigned sub_flags = flags;
1600
1601                sub_flags &= ~GET_SHA1_DISAMBIGUATORS;
1602                sub_flags |= GET_SHA1_TREEISH;
1603
1604                if (!get_sha1_1(name, len, tree_sha1, sub_flags)) {
1605                        const char *filename = cp+1;
1606                        char *new_filename = NULL;
1607
1608                        new_filename = resolve_relative_path(filename);
1609                        if (new_filename)
1610                                filename = new_filename;
1611                        if (flags & GET_SHA1_FOLLOW_SYMLINKS) {
1612                                ret = get_tree_entry_follow_symlinks(tree_sha1,
1613                                        filename, sha1, &oc->symlink_path,
1614                                        &oc->mode);
1615                        } else {
1616                                ret = get_tree_entry(tree_sha1, filename,
1617                                                     sha1, &oc->mode);
1618                                if (ret && only_to_die) {
1619                                        diagnose_invalid_sha1_path(prefix,
1620                                                                   filename,
1621                                                                   tree_sha1,
1622                                                                   name, len);
1623                                }
1624                        }
1625                        hashcpy(oc->tree, tree_sha1);
1626                        if (flags & GET_SHA1_RECORD_PATH)
1627                                oc->path = xstrdup(filename);
1628
1629                        free(new_filename);
1630                        return ret;
1631                } else {
1632                        if (only_to_die)
1633                                die("Invalid object name '%.*s'.", len, name);
1634                }
1635        }
1636        return ret;
1637}
1638
1639/*
1640 * Call this function when you know "name" given by the end user must
1641 * name an object but it doesn't; the function _may_ die with a better
1642 * diagnostic message than "no such object 'name'", e.g. "Path 'doc' does not
1643 * exist in 'HEAD'" when given "HEAD:doc", or it may return in which case
1644 * you have a chance to diagnose the error further.
1645 */
1646void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
1647{
1648        struct object_context oc;
1649        unsigned char sha1[20];
1650        get_sha1_with_context_1(name, GET_SHA1_ONLY_TO_DIE, prefix, sha1, &oc);
1651}
1652
1653int get_sha1_with_context(const char *str, unsigned flags, unsigned char *sha1, struct object_context *oc)
1654{
1655        if (flags & GET_SHA1_FOLLOW_SYMLINKS && flags & GET_SHA1_ONLY_TO_DIE)
1656                die("BUG: incompatible flags for get_sha1_with_context");
1657        return get_sha1_with_context_1(str, flags, NULL, sha1, oc);
1658}