sha1_name.con commit Merge branch 'rs/checkout-am-fix-unborn' into maint (a207ad7)
   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#include "sha1-array.h"
  11
  12static int get_sha1_oneline(const char *, unsigned char *, struct commit_list *);
  13
  14typedef int (*disambiguate_hint_fn)(const struct object_id *, void *);
  15
  16struct disambiguate_state {
  17        int len; /* length of prefix in hex chars */
  18        char hex_pfx[GIT_MAX_HEXSZ + 1];
  19        struct object_id bin_pfx;
  20
  21        disambiguate_hint_fn fn;
  22        void *cb_data;
  23        struct object_id candidate;
  24        unsigned candidate_exists:1;
  25        unsigned candidate_checked:1;
  26        unsigned candidate_ok:1;
  27        unsigned disambiguate_fn_used:1;
  28        unsigned ambiguous:1;
  29        unsigned always_call_fn:1;
  30};
  31
  32static void update_candidates(struct disambiguate_state *ds, const struct object_id *current)
  33{
  34        if (ds->always_call_fn) {
  35                ds->ambiguous = ds->fn(current, ds->cb_data) ? 1 : 0;
  36                return;
  37        }
  38        if (!ds->candidate_exists) {
  39                /* this is the first candidate */
  40                oidcpy(&ds->candidate, current);
  41                ds->candidate_exists = 1;
  42                return;
  43        } else if (!oidcmp(&ds->candidate, current)) {
  44                /* the same as what we already have seen */
  45                return;
  46        }
  47
  48        if (!ds->fn) {
  49                /* cannot disambiguate between ds->candidate and current */
  50                ds->ambiguous = 1;
  51                return;
  52        }
  53
  54        if (!ds->candidate_checked) {
  55                ds->candidate_ok = ds->fn(&ds->candidate, ds->cb_data);
  56                ds->disambiguate_fn_used = 1;
  57                ds->candidate_checked = 1;
  58        }
  59
  60        if (!ds->candidate_ok) {
  61                /* discard the candidate; we know it does not satisfy fn */
  62                oidcpy(&ds->candidate, current);
  63                ds->candidate_checked = 0;
  64                return;
  65        }
  66
  67        /* if we reach this point, we know ds->candidate satisfies fn */
  68        if (ds->fn(current, ds->cb_data)) {
  69                /*
  70                 * if both current and candidate satisfy fn, we cannot
  71                 * disambiguate.
  72                 */
  73                ds->candidate_ok = 0;
  74                ds->ambiguous = 1;
  75        }
  76
  77        /* otherwise, current can be discarded and candidate is still good */
  78}
  79
  80static void find_short_object_filename(struct disambiguate_state *ds)
  81{
  82        struct alternate_object_database *alt;
  83        char hex[GIT_MAX_HEXSZ];
  84        static struct alternate_object_database *fakeent;
  85
  86        if (!fakeent) {
  87                /*
  88                 * Create a "fake" alternate object database that
  89                 * points to our own object database, to make it
  90                 * easier to get a temporary working space in
  91                 * alt->name/alt->base while iterating over the
  92                 * object databases including our own.
  93                 */
  94                fakeent = alloc_alt_odb(get_object_directory());
  95        }
  96        fakeent->next = alt_odb_list;
  97
  98        xsnprintf(hex, sizeof(hex), "%.2s", ds->hex_pfx);
  99        for (alt = fakeent; alt && !ds->ambiguous; alt = alt->next) {
 100                struct strbuf *buf = alt_scratch_buf(alt);
 101                struct dirent *de;
 102                DIR *dir;
 103
 104                strbuf_addf(buf, "%.2s/", ds->hex_pfx);
 105                dir = opendir(buf->buf);
 106                if (!dir)
 107                        continue;
 108
 109                while (!ds->ambiguous && (de = readdir(dir)) != NULL) {
 110                        struct object_id oid;
 111
 112                        if (strlen(de->d_name) != GIT_SHA1_HEXSZ - 2)
 113                                continue;
 114                        if (memcmp(de->d_name, ds->hex_pfx + 2, ds->len - 2))
 115                                continue;
 116                        memcpy(hex + 2, de->d_name, GIT_SHA1_HEXSZ - 2);
 117                        if (!get_oid_hex(hex, &oid))
 118                                update_candidates(ds, &oid);
 119                }
 120                closedir(dir);
 121        }
 122}
 123
 124static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
 125{
 126        do {
 127                if (*a != *b)
 128                        return 0;
 129                a++;
 130                b++;
 131                len -= 2;
 132        } while (len > 1);
 133        if (len)
 134                if ((*a ^ *b) & 0xf0)
 135                        return 0;
 136        return 1;
 137}
 138
 139static void unique_in_pack(struct packed_git *p,
 140                           struct disambiguate_state *ds)
 141{
 142        uint32_t num, last, i, first = 0;
 143        const struct object_id *current = NULL;
 144
 145        open_pack_index(p);
 146        num = p->num_objects;
 147        last = num;
 148        while (first < last) {
 149                uint32_t mid = (first + last) / 2;
 150                const unsigned char *current;
 151                int cmp;
 152
 153                current = nth_packed_object_sha1(p, mid);
 154                cmp = hashcmp(ds->bin_pfx.hash, current);
 155                if (!cmp) {
 156                        first = mid;
 157                        break;
 158                }
 159                if (cmp > 0) {
 160                        first = mid+1;
 161                        continue;
 162                }
 163                last = mid;
 164        }
 165
 166        /*
 167         * At this point, "first" is the location of the lowest object
 168         * with an object name that could match "bin_pfx".  See if we have
 169         * 0, 1 or more objects that actually match(es).
 170         */
 171        for (i = first; i < num && !ds->ambiguous; i++) {
 172                struct object_id oid;
 173                current = nth_packed_object_oid(&oid, p, i);
 174                if (!match_sha(ds->len, ds->bin_pfx.hash, current->hash))
 175                        break;
 176                update_candidates(ds, current);
 177        }
 178}
 179
 180static void find_short_packed_object(struct disambiguate_state *ds)
 181{
 182        struct packed_git *p;
 183
 184        prepare_packed_git();
 185        for (p = packed_git; p && !ds->ambiguous; p = p->next)
 186                unique_in_pack(p, ds);
 187}
 188
 189#define SHORT_NAME_NOT_FOUND (-1)
 190#define SHORT_NAME_AMBIGUOUS (-2)
 191
 192static int finish_object_disambiguation(struct disambiguate_state *ds,
 193                                        unsigned char *sha1)
 194{
 195        if (ds->ambiguous)
 196                return SHORT_NAME_AMBIGUOUS;
 197
 198        if (!ds->candidate_exists)
 199                return SHORT_NAME_NOT_FOUND;
 200
 201        if (!ds->candidate_checked)
 202                /*
 203                 * If this is the only candidate, there is no point
 204                 * calling the disambiguation hint callback.
 205                 *
 206                 * On the other hand, if the current candidate
 207                 * replaced an earlier candidate that did _not_ pass
 208                 * the disambiguation hint callback, then we do have
 209                 * more than one objects that match the short name
 210                 * given, so we should make sure this one matches;
 211                 * otherwise, if we discovered this one and the one
 212                 * that we previously discarded in the reverse order,
 213                 * we would end up showing different results in the
 214                 * same repository!
 215                 */
 216                ds->candidate_ok = (!ds->disambiguate_fn_used ||
 217                                    ds->fn(&ds->candidate, ds->cb_data));
 218
 219        if (!ds->candidate_ok)
 220                return SHORT_NAME_AMBIGUOUS;
 221
 222        hashcpy(sha1, ds->candidate.hash);
 223        return 0;
 224}
 225
 226static int disambiguate_commit_only(const struct object_id *oid, void *cb_data_unused)
 227{
 228        int kind = sha1_object_info(oid->hash, NULL);
 229        return kind == OBJ_COMMIT;
 230}
 231
 232static int disambiguate_committish_only(const struct object_id *oid, void *cb_data_unused)
 233{
 234        struct object *obj;
 235        int kind;
 236
 237        kind = sha1_object_info(oid->hash, NULL);
 238        if (kind == OBJ_COMMIT)
 239                return 1;
 240        if (kind != OBJ_TAG)
 241                return 0;
 242
 243        /* We need to do this the hard way... */
 244        obj = deref_tag(parse_object(oid->hash), NULL, 0);
 245        if (obj && obj->type == OBJ_COMMIT)
 246                return 1;
 247        return 0;
 248}
 249
 250static int disambiguate_tree_only(const struct object_id *oid, void *cb_data_unused)
 251{
 252        int kind = sha1_object_info(oid->hash, NULL);
 253        return kind == OBJ_TREE;
 254}
 255
 256static int disambiguate_treeish_only(const struct object_id *oid, void *cb_data_unused)
 257{
 258        struct object *obj;
 259        int kind;
 260
 261        kind = sha1_object_info(oid->hash, NULL);
 262        if (kind == OBJ_TREE || kind == OBJ_COMMIT)
 263                return 1;
 264        if (kind != OBJ_TAG)
 265                return 0;
 266
 267        /* We need to do this the hard way... */
 268        obj = deref_tag(parse_object(oid->hash), NULL, 0);
 269        if (obj && (obj->type == OBJ_TREE || obj->type == OBJ_COMMIT))
 270                return 1;
 271        return 0;
 272}
 273
 274static int disambiguate_blob_only(const struct object_id *oid, void *cb_data_unused)
 275{
 276        int kind = sha1_object_info(oid->hash, NULL);
 277        return kind == OBJ_BLOB;
 278}
 279
 280static disambiguate_hint_fn default_disambiguate_hint;
 281
 282int set_disambiguate_hint_config(const char *var, const char *value)
 283{
 284        static const struct {
 285                const char *name;
 286                disambiguate_hint_fn fn;
 287        } hints[] = {
 288                { "none", NULL },
 289                { "commit", disambiguate_commit_only },
 290                { "committish", disambiguate_committish_only },
 291                { "tree", disambiguate_tree_only },
 292                { "treeish", disambiguate_treeish_only },
 293                { "blob", disambiguate_blob_only }
 294        };
 295        int i;
 296
 297        if (!value)
 298                return config_error_nonbool(var);
 299
 300        for (i = 0; i < ARRAY_SIZE(hints); i++) {
 301                if (!strcasecmp(value, hints[i].name)) {
 302                        default_disambiguate_hint = hints[i].fn;
 303                        return 0;
 304                }
 305        }
 306
 307        return error("unknown hint type for '%s': %s", var, value);
 308}
 309
 310static int init_object_disambiguation(const char *name, int len,
 311                                      struct disambiguate_state *ds)
 312{
 313        int i;
 314
 315        if (len < MINIMUM_ABBREV || len > GIT_SHA1_HEXSZ)
 316                return -1;
 317
 318        memset(ds, 0, sizeof(*ds));
 319
 320        for (i = 0; i < len ;i++) {
 321                unsigned char c = name[i];
 322                unsigned char val;
 323                if (c >= '0' && c <= '9')
 324                        val = c - '0';
 325                else if (c >= 'a' && c <= 'f')
 326                        val = c - 'a' + 10;
 327                else if (c >= 'A' && c <='F') {
 328                        val = c - 'A' + 10;
 329                        c -= 'A' - 'a';
 330                }
 331                else
 332                        return -1;
 333                ds->hex_pfx[i] = c;
 334                if (!(i & 1))
 335                        val <<= 4;
 336                ds->bin_pfx.hash[i >> 1] |= val;
 337        }
 338
 339        ds->len = len;
 340        ds->hex_pfx[len] = '\0';
 341        prepare_alt_odb();
 342        return 0;
 343}
 344
 345static int show_ambiguous_object(const struct object_id *oid, void *data)
 346{
 347        const struct disambiguate_state *ds = data;
 348        struct strbuf desc = STRBUF_INIT;
 349        int type;
 350
 351
 352        if (ds->fn && !ds->fn(oid, ds->cb_data))
 353                return 0;
 354
 355        type = sha1_object_info(oid->hash, NULL);
 356        if (type == OBJ_COMMIT) {
 357                struct commit *commit = lookup_commit(oid->hash);
 358                if (commit) {
 359                        struct pretty_print_context pp = {0};
 360                        pp.date_mode.type = DATE_SHORT;
 361                        format_commit_message(commit, " %ad - %s", &desc, &pp);
 362                }
 363        } else if (type == OBJ_TAG) {
 364                struct tag *tag = lookup_tag(oid->hash);
 365                if (!parse_tag(tag) && tag->tag)
 366                        strbuf_addf(&desc, " %s", tag->tag);
 367        }
 368
 369        advise("  %s %s%s",
 370               find_unique_abbrev(oid->hash, DEFAULT_ABBREV),
 371               typename(type) ? typename(type) : "unknown type",
 372               desc.buf);
 373
 374        strbuf_release(&desc);
 375        return 0;
 376}
 377
 378static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 379                          unsigned flags)
 380{
 381        int status;
 382        struct disambiguate_state ds;
 383        int quietly = !!(flags & GET_SHA1_QUIETLY);
 384
 385        if (init_object_disambiguation(name, len, &ds) < 0)
 386                return -1;
 387
 388        if (HAS_MULTI_BITS(flags & GET_SHA1_DISAMBIGUATORS))
 389                die("BUG: multiple get_short_sha1 disambiguator flags");
 390
 391        if (flags & GET_SHA1_COMMIT)
 392                ds.fn = disambiguate_commit_only;
 393        else if (flags & GET_SHA1_COMMITTISH)
 394                ds.fn = disambiguate_committish_only;
 395        else if (flags & GET_SHA1_TREE)
 396                ds.fn = disambiguate_tree_only;
 397        else if (flags & GET_SHA1_TREEISH)
 398                ds.fn = disambiguate_treeish_only;
 399        else if (flags & GET_SHA1_BLOB)
 400                ds.fn = disambiguate_blob_only;
 401        else
 402                ds.fn = default_disambiguate_hint;
 403
 404        find_short_object_filename(&ds);
 405        find_short_packed_object(&ds);
 406        status = finish_object_disambiguation(&ds, sha1);
 407
 408        if (!quietly && (status == SHORT_NAME_AMBIGUOUS)) {
 409                error(_("short SHA1 %s is ambiguous"), ds.hex_pfx);
 410
 411                /*
 412                 * We may still have ambiguity if we simply saw a series of
 413                 * candidates that did not satisfy our hint function. In
 414                 * that case, we still want to show them, so disable the hint
 415                 * function entirely.
 416                 */
 417                if (!ds.ambiguous)
 418                        ds.fn = NULL;
 419
 420                advise(_("The candidates are:"));
 421                for_each_abbrev(ds.hex_pfx, show_ambiguous_object, &ds);
 422        }
 423
 424        return status;
 425}
 426
 427static int collect_ambiguous(const struct object_id *oid, void *data)
 428{
 429        oid_array_append(data, oid);
 430        return 0;
 431}
 432
 433int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
 434{
 435        struct oid_array collect = OID_ARRAY_INIT;
 436        struct disambiguate_state ds;
 437        int ret;
 438
 439        if (init_object_disambiguation(prefix, strlen(prefix), &ds) < 0)
 440                return -1;
 441
 442        ds.always_call_fn = 1;
 443        ds.fn = collect_ambiguous;
 444        ds.cb_data = &collect;
 445        find_short_object_filename(&ds);
 446        find_short_packed_object(&ds);
 447
 448        ret = oid_array_for_each_unique(&collect, fn, cb_data);
 449        oid_array_clear(&collect);
 450        return ret;
 451}
 452
 453/*
 454 * Return the slot of the most-significant bit set in "val". There are various
 455 * ways to do this quickly with fls() or __builtin_clzl(), but speed is
 456 * probably not a big deal here.
 457 */
 458static unsigned msb(unsigned long val)
 459{
 460        unsigned r = 0;
 461        while (val >>= 1)
 462                r++;
 463        return r;
 464}
 465
 466int find_unique_abbrev_r(char *hex, const unsigned char *sha1, int len)
 467{
 468        int status, exists;
 469
 470        if (len < 0) {
 471                unsigned long count = approximate_object_count();
 472                /*
 473                 * Add one because the MSB only tells us the highest bit set,
 474                 * not including the value of all the _other_ bits (so "15"
 475                 * is only one off of 2^4, but the MSB is the 3rd bit.
 476                 */
 477                len = msb(count) + 1;
 478                /*
 479                 * We now know we have on the order of 2^len objects, which
 480                 * expects a collision at 2^(len/2). But we also care about hex
 481                 * chars, not bits, and there are 4 bits per hex. So all
 482                 * together we need to divide by 2; but we also want to round
 483                 * odd numbers up, hence adding one before dividing.
 484                 */
 485                len = (len + 1) / 2;
 486                /*
 487                 * For very small repos, we stick with our regular fallback.
 488                 */
 489                if (len < FALLBACK_DEFAULT_ABBREV)
 490                        len = FALLBACK_DEFAULT_ABBREV;
 491        }
 492
 493        sha1_to_hex_r(hex, sha1);
 494        if (len == 40 || !len)
 495                return 40;
 496        exists = has_sha1_file(sha1);
 497        while (len < 40) {
 498                unsigned char sha1_ret[20];
 499                status = get_short_sha1(hex, len, sha1_ret, GET_SHA1_QUIETLY);
 500                if (exists
 501                    ? !status
 502                    : status == SHORT_NAME_NOT_FOUND) {
 503                        hex[len] = 0;
 504                        return len;
 505                }
 506                len++;
 507        }
 508        return len;
 509}
 510
 511const char *find_unique_abbrev(const unsigned char *sha1, int len)
 512{
 513        static int bufno;
 514        static char hexbuffer[4][GIT_MAX_HEXSZ + 1];
 515        char *hex = hexbuffer[bufno];
 516        bufno = (bufno + 1) % ARRAY_SIZE(hexbuffer);
 517        find_unique_abbrev_r(hex, sha1, len);
 518        return hex;
 519}
 520
 521static int ambiguous_path(const char *path, int len)
 522{
 523        int slash = 1;
 524        int cnt;
 525
 526        for (cnt = 0; cnt < len; cnt++) {
 527                switch (*path++) {
 528                case '\0':
 529                        break;
 530                case '/':
 531                        if (slash)
 532                                break;
 533                        slash = 1;
 534                        continue;
 535                case '.':
 536                        continue;
 537                default:
 538                        slash = 0;
 539                        continue;
 540                }
 541                break;
 542        }
 543        return slash;
 544}
 545
 546static inline int at_mark(const char *string, int len,
 547                          const char **suffix, int nr)
 548{
 549        int i;
 550
 551        for (i = 0; i < nr; i++) {
 552                int suffix_len = strlen(suffix[i]);
 553                if (suffix_len <= len
 554                    && !strncasecmp(string, suffix[i], suffix_len))
 555                        return suffix_len;
 556        }
 557        return 0;
 558}
 559
 560static inline int upstream_mark(const char *string, int len)
 561{
 562        const char *suffix[] = { "@{upstream}", "@{u}" };
 563        return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
 564}
 565
 566static inline int push_mark(const char *string, int len)
 567{
 568        const char *suffix[] = { "@{push}" };
 569        return at_mark(string, len, suffix, ARRAY_SIZE(suffix));
 570}
 571
 572static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags);
 573static int interpret_nth_prior_checkout(const char *name, int namelen, struct strbuf *buf);
 574
 575static int get_sha1_basic(const char *str, int len, unsigned char *sha1,
 576                          unsigned int flags)
 577{
 578        static const char *warn_msg = "refname '%.*s' is ambiguous.";
 579        static const char *object_name_msg = N_(
 580        "Git normally never creates a ref that ends with 40 hex characters\n"
 581        "because it will be ignored when you just specify 40-hex. These refs\n"
 582        "may be created by mistake. For example,\n"
 583        "\n"
 584        "  git checkout -b $br $(git rev-parse ...)\n"
 585        "\n"
 586        "where \"$br\" is somehow empty and a 40-hex ref is created. Please\n"
 587        "examine these refs and maybe delete them. Turn this message off by\n"
 588        "running \"git config advice.objectNameWarning false\"");
 589        unsigned char tmp_sha1[20];
 590        char *real_ref = NULL;
 591        int refs_found = 0;
 592        int at, reflog_len, nth_prior = 0;
 593
 594        if (len == 40 && !get_sha1_hex(str, sha1)) {
 595                if (warn_ambiguous_refs && warn_on_object_refname_ambiguity) {
 596                        refs_found = dwim_ref(str, len, tmp_sha1, &real_ref);
 597                        if (refs_found > 0) {
 598                                warning(warn_msg, len, str);
 599                                if (advice_object_name_warning)
 600                                        fprintf(stderr, "%s\n", _(object_name_msg));
 601                        }
 602                        free(real_ref);
 603                }
 604                return 0;
 605        }
 606
 607        /* basic@{time or number or -number} format to query ref-log */
 608        reflog_len = at = 0;
 609        if (len && str[len-1] == '}') {
 610                for (at = len-4; at >= 0; at--) {
 611                        if (str[at] == '@' && str[at+1] == '{') {
 612                                if (str[at+2] == '-') {
 613                                        if (at != 0)
 614                                                /* @{-N} not at start */
 615                                                return -1;
 616                                        nth_prior = 1;
 617                                        continue;
 618                                }
 619                                if (!upstream_mark(str + at, len - at) &&
 620                                    !push_mark(str + at, len - at)) {
 621                                        reflog_len = (len-1) - (at+2);
 622                                        len = at;
 623                                }
 624                                break;
 625                        }
 626                }
 627        }
 628
 629        /* Accept only unambiguous ref paths. */
 630        if (len && ambiguous_path(str, len))
 631                return -1;
 632
 633        if (nth_prior) {
 634                struct strbuf buf = STRBUF_INIT;
 635                int detached;
 636
 637                if (interpret_nth_prior_checkout(str, len, &buf) > 0) {
 638                        detached = (buf.len == 40 && !get_sha1_hex(buf.buf, sha1));
 639                        strbuf_release(&buf);
 640                        if (detached)
 641                                return 0;
 642                }
 643        }
 644
 645        if (!len && reflog_len)
 646                /* allow "@{...}" to mean the current branch reflog */
 647                refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
 648        else if (reflog_len)
 649                refs_found = dwim_log(str, len, sha1, &real_ref);
 650        else
 651                refs_found = dwim_ref(str, len, sha1, &real_ref);
 652
 653        if (!refs_found)
 654                return -1;
 655
 656        if (warn_ambiguous_refs && !(flags & GET_SHA1_QUIETLY) &&
 657            (refs_found > 1 ||
 658             !get_short_sha1(str, len, tmp_sha1, GET_SHA1_QUIETLY)))
 659                warning(warn_msg, len, str);
 660
 661        if (reflog_len) {
 662                int nth, i;
 663                unsigned long at_time;
 664                unsigned long co_time;
 665                int co_tz, co_cnt;
 666
 667                /* Is it asking for N-th entry, or approxidate? */
 668                for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 669                        char ch = str[at+2+i];
 670                        if ('0' <= ch && ch <= '9')
 671                                nth = nth * 10 + ch - '0';
 672                        else
 673                                nth = -1;
 674                }
 675                if (100000000 <= nth) {
 676                        at_time = nth;
 677                        nth = -1;
 678                } else if (0 <= nth)
 679                        at_time = 0;
 680                else {
 681                        int errors = 0;
 682                        char *tmp = xstrndup(str + at + 2, reflog_len);
 683                        at_time = approxidate_careful(tmp, &errors);
 684                        free(tmp);
 685                        if (errors) {
 686                                free(real_ref);
 687                                return -1;
 688                        }
 689                }
 690                if (read_ref_at(real_ref, flags, at_time, nth, sha1, NULL,
 691                                &co_time, &co_tz, &co_cnt)) {
 692                        if (!len) {
 693                                if (starts_with(real_ref, "refs/heads/")) {
 694                                        str = real_ref + 11;
 695                                        len = strlen(real_ref + 11);
 696                                } else {
 697                                        /* detached HEAD */
 698                                        str = "HEAD";
 699                                        len = 4;
 700                                }
 701                        }
 702                        if (at_time) {
 703                                if (!(flags & GET_SHA1_QUIETLY)) {
 704                                        warning("Log for '%.*s' only goes "
 705                                                "back to %s.", len, str,
 706                                                show_date(co_time, co_tz, DATE_MODE(RFC2822)));
 707                                }
 708                        } else {
 709                                if (flags & GET_SHA1_QUIETLY) {
 710                                        exit(128);
 711                                }
 712                                die("Log for '%.*s' only has %d entries.",
 713                                    len, str, co_cnt);
 714                        }
 715                }
 716        }
 717
 718        free(real_ref);
 719        return 0;
 720}
 721
 722static int get_parent(const char *name, int len,
 723                      unsigned char *result, int idx)
 724{
 725        unsigned char sha1[20];
 726        int ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 727        struct commit *commit;
 728        struct commit_list *p;
 729
 730        if (ret)
 731                return ret;
 732        commit = lookup_commit_reference(sha1);
 733        if (parse_commit(commit))
 734                return -1;
 735        if (!idx) {
 736                hashcpy(result, commit->object.oid.hash);
 737                return 0;
 738        }
 739        p = commit->parents;
 740        while (p) {
 741                if (!--idx) {
 742                        hashcpy(result, p->item->object.oid.hash);
 743                        return 0;
 744                }
 745                p = p->next;
 746        }
 747        return -1;
 748}
 749
 750static int get_nth_ancestor(const char *name, int len,
 751                            unsigned char *result, int generation)
 752{
 753        unsigned char sha1[20];
 754        struct commit *commit;
 755        int ret;
 756
 757        ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 758        if (ret)
 759                return ret;
 760        commit = lookup_commit_reference(sha1);
 761        if (!commit)
 762                return -1;
 763
 764        while (generation--) {
 765                if (parse_commit(commit) || !commit->parents)
 766                        return -1;
 767                commit = commit->parents->item;
 768        }
 769        hashcpy(result, commit->object.oid.hash);
 770        return 0;
 771}
 772
 773struct object *peel_to_type(const char *name, int namelen,
 774                            struct object *o, enum object_type expected_type)
 775{
 776        if (name && !namelen)
 777                namelen = strlen(name);
 778        while (1) {
 779                if (!o || (!o->parsed && !parse_object(o->oid.hash)))
 780                        return NULL;
 781                if (expected_type == OBJ_ANY || o->type == expected_type)
 782                        return o;
 783                if (o->type == OBJ_TAG)
 784                        o = ((struct tag*) o)->tagged;
 785                else if (o->type == OBJ_COMMIT)
 786                        o = &(((struct commit *) o)->tree->object);
 787                else {
 788                        if (name)
 789                                error("%.*s: expected %s type, but the object "
 790                                      "dereferences to %s type",
 791                                      namelen, name, typename(expected_type),
 792                                      typename(o->type));
 793                        return NULL;
 794                }
 795        }
 796}
 797
 798static int peel_onion(const char *name, int len, unsigned char *sha1,
 799                      unsigned lookup_flags)
 800{
 801        unsigned char outer[20];
 802        const char *sp;
 803        unsigned int expected_type = 0;
 804        struct object *o;
 805
 806        /*
 807         * "ref^{type}" dereferences ref repeatedly until you cannot
 808         * dereference anymore, or you get an object of given type,
 809         * whichever comes first.  "ref^{}" means just dereference
 810         * tags until you get a non-tag.  "ref^0" is a shorthand for
 811         * "ref^{commit}".  "commit^{tree}" could be used to find the
 812         * top-level tree of the given commit.
 813         */
 814        if (len < 4 || name[len-1] != '}')
 815                return -1;
 816
 817        for (sp = name + len - 1; name <= sp; sp--) {
 818                int ch = *sp;
 819                if (ch == '{' && name < sp && sp[-1] == '^')
 820                        break;
 821        }
 822        if (sp <= name)
 823                return -1;
 824
 825        sp++; /* beginning of type name, or closing brace for empty */
 826        if (starts_with(sp, "commit}"))
 827                expected_type = OBJ_COMMIT;
 828        else if (starts_with(sp, "tag}"))
 829                expected_type = OBJ_TAG;
 830        else if (starts_with(sp, "tree}"))
 831                expected_type = OBJ_TREE;
 832        else if (starts_with(sp, "blob}"))
 833                expected_type = OBJ_BLOB;
 834        else if (starts_with(sp, "object}"))
 835                expected_type = OBJ_ANY;
 836        else if (sp[0] == '}')
 837                expected_type = OBJ_NONE;
 838        else if (sp[0] == '/')
 839                expected_type = OBJ_COMMIT;
 840        else
 841                return -1;
 842
 843        lookup_flags &= ~GET_SHA1_DISAMBIGUATORS;
 844        if (expected_type == OBJ_COMMIT)
 845                lookup_flags |= GET_SHA1_COMMITTISH;
 846        else if (expected_type == OBJ_TREE)
 847                lookup_flags |= GET_SHA1_TREEISH;
 848
 849        if (get_sha1_1(name, sp - name - 2, outer, lookup_flags))
 850                return -1;
 851
 852        o = parse_object(outer);
 853        if (!o)
 854                return -1;
 855        if (!expected_type) {
 856                o = deref_tag(o, name, sp - name - 2);
 857                if (!o || (!o->parsed && !parse_object(o->oid.hash)))
 858                        return -1;
 859                hashcpy(sha1, o->oid.hash);
 860                return 0;
 861        }
 862
 863        /*
 864         * At this point, the syntax look correct, so
 865         * if we do not get the needed object, we should
 866         * barf.
 867         */
 868        o = peel_to_type(name, len, o, expected_type);
 869        if (!o)
 870                return -1;
 871
 872        hashcpy(sha1, o->oid.hash);
 873        if (sp[0] == '/') {
 874                /* "$commit^{/foo}" */
 875                char *prefix;
 876                int ret;
 877                struct commit_list *list = NULL;
 878
 879                /*
 880                 * $commit^{/}. Some regex implementation may reject.
 881                 * We don't need regex anyway. '' pattern always matches.
 882                 */
 883                if (sp[1] == '}')
 884                        return 0;
 885
 886                prefix = xstrndup(sp + 1, name + len - 1 - (sp + 1));
 887                commit_list_insert((struct commit *)o, &list);
 888                ret = get_sha1_oneline(prefix, sha1, list);
 889                free(prefix);
 890                return ret;
 891        }
 892        return 0;
 893}
 894
 895static int get_describe_name(const char *name, int len, unsigned char *sha1)
 896{
 897        const char *cp;
 898        unsigned flags = GET_SHA1_QUIETLY | GET_SHA1_COMMIT;
 899
 900        for (cp = name + len - 1; name + 2 <= cp; cp--) {
 901                char ch = *cp;
 902                if (!isxdigit(ch)) {
 903                        /* We must be looking at g in "SOMETHING-g"
 904                         * for it to be describe output.
 905                         */
 906                        if (ch == 'g' && cp[-1] == '-') {
 907                                cp++;
 908                                len -= cp - name;
 909                                return get_short_sha1(cp, len, sha1, flags);
 910                        }
 911                }
 912        }
 913        return -1;
 914}
 915
 916static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags)
 917{
 918        int ret, has_suffix;
 919        const char *cp;
 920
 921        /*
 922         * "name~3" is "name^^^", "name~" is "name~1", and "name^" is "name^1".
 923         */
 924        has_suffix = 0;
 925        for (cp = name + len - 1; name <= cp; cp--) {
 926                int ch = *cp;
 927                if ('0' <= ch && ch <= '9')
 928                        continue;
 929                if (ch == '~' || ch == '^')
 930                        has_suffix = ch;
 931                break;
 932        }
 933
 934        if (has_suffix) {
 935                int num = 0;
 936                int len1 = cp - name;
 937                cp++;
 938                while (cp < name + len)
 939                        num = num * 10 + *cp++ - '0';
 940                if (!num && len1 == len - 1)
 941                        num = 1;
 942                if (has_suffix == '^')
 943                        return get_parent(name, len1, sha1, num);
 944                /* else if (has_suffix == '~') -- goes without saying */
 945                return get_nth_ancestor(name, len1, sha1, num);
 946        }
 947
 948        ret = peel_onion(name, len, sha1, lookup_flags);
 949        if (!ret)
 950                return 0;
 951
 952        ret = get_sha1_basic(name, len, sha1, lookup_flags);
 953        if (!ret)
 954                return 0;
 955
 956        /* It could be describe output that is "SOMETHING-gXXXX" */
 957        ret = get_describe_name(name, len, sha1);
 958        if (!ret)
 959                return 0;
 960
 961        return get_short_sha1(name, len, sha1, lookup_flags);
 962}
 963
 964/*
 965 * This interprets names like ':/Initial revision of "git"' by searching
 966 * through history and returning the first commit whose message starts
 967 * the given regular expression.
 968 *
 969 * For negative-matching, prefix the pattern-part with '!-', like: ':/!-WIP'.
 970 *
 971 * For a literal '!' character at the beginning of a pattern, you have to repeat
 972 * that, like: ':/!!foo'
 973 *
 974 * For future extension, all other sequences beginning with ':/!' are reserved.
 975 */
 976
 977/* Remember to update object flag allocation in object.h */
 978#define ONELINE_SEEN (1u<<20)
 979
 980static int handle_one_ref(const char *path, const struct object_id *oid,
 981                          int flag, void *cb_data)
 982{
 983        struct commit_list **list = cb_data;
 984        struct object *object = parse_object(oid->hash);
 985        if (!object)
 986                return 0;
 987        if (object->type == OBJ_TAG) {
 988                object = deref_tag(object, path, strlen(path));
 989                if (!object)
 990                        return 0;
 991        }
 992        if (object->type != OBJ_COMMIT)
 993                return 0;
 994        commit_list_insert((struct commit *)object, list);
 995        return 0;
 996}
 997
 998static int get_sha1_oneline(const char *prefix, unsigned char *sha1,
 999                            struct commit_list *list)
1000{
1001        struct commit_list *backup = NULL, *l;
1002        int found = 0;
1003        int negative = 0;
1004        regex_t regex;
1005
1006        if (prefix[0] == '!') {
1007                prefix++;
1008
1009                if (prefix[0] == '-') {
1010                        prefix++;
1011                        negative = 1;
1012                } else if (prefix[0] != '!') {
1013                        return -1;
1014                }
1015        }
1016
1017        if (regcomp(&regex, prefix, REG_EXTENDED))
1018                return -1;
1019
1020        for (l = list; l; l = l->next) {
1021                l->item->object.flags |= ONELINE_SEEN;
1022                commit_list_insert(l->item, &backup);
1023        }
1024        while (list) {
1025                const char *p, *buf;
1026                struct commit *commit;
1027                int matches;
1028
1029                commit = pop_most_recent_commit(&list, ONELINE_SEEN);
1030                if (!parse_object(commit->object.oid.hash))
1031                        continue;
1032                buf = get_commit_buffer(commit, NULL);
1033                p = strstr(buf, "\n\n");
1034                matches = negative ^ (p && !regexec(&regex, p + 2, 0, NULL, 0));
1035                unuse_commit_buffer(commit, buf);
1036
1037                if (matches) {
1038                        hashcpy(sha1, commit->object.oid.hash);
1039                        found = 1;
1040                        break;
1041                }
1042        }
1043        regfree(&regex);
1044        free_commit_list(list);
1045        for (l = backup; l; l = l->next)
1046                clear_commit_marks(l->item, ONELINE_SEEN);
1047        free_commit_list(backup);
1048        return found ? 0 : -1;
1049}
1050
1051struct grab_nth_branch_switch_cbdata {
1052        int remaining;
1053        struct strbuf buf;
1054};
1055
1056static int grab_nth_branch_switch(struct object_id *ooid, struct object_id *noid,
1057                                  const char *email, unsigned long timestamp, int tz,
1058                                  const char *message, void *cb_data)
1059{
1060        struct grab_nth_branch_switch_cbdata *cb = cb_data;
1061        const char *match = NULL, *target = NULL;
1062        size_t len;
1063
1064        if (skip_prefix(message, "checkout: moving from ", &match))
1065                target = strstr(match, " to ");
1066
1067        if (!match || !target)
1068                return 0;
1069        if (--(cb->remaining) == 0) {
1070                len = target - match;
1071                strbuf_reset(&cb->buf);
1072                strbuf_add(&cb->buf, match, len);
1073                return 1; /* we are done */
1074        }
1075        return 0;
1076}
1077
1078/*
1079 * Parse @{-N} syntax, return the number of characters parsed
1080 * if successful; otherwise signal an error with negative value.
1081 */
1082static int interpret_nth_prior_checkout(const char *name, int namelen,
1083                                        struct strbuf *buf)
1084{
1085        long nth;
1086        int retval;
1087        struct grab_nth_branch_switch_cbdata cb;
1088        const char *brace;
1089        char *num_end;
1090
1091        if (namelen < 4)
1092                return -1;
1093        if (name[0] != '@' || name[1] != '{' || name[2] != '-')
1094                return -1;
1095        brace = memchr(name, '}', namelen);
1096        if (!brace)
1097                return -1;
1098        nth = strtol(name + 3, &num_end, 10);
1099        if (num_end != brace)
1100                return -1;
1101        if (nth <= 0)
1102                return -1;
1103        cb.remaining = nth;
1104        strbuf_init(&cb.buf, 20);
1105
1106        retval = 0;
1107        if (0 < for_each_reflog_ent_reverse("HEAD", grab_nth_branch_switch, &cb)) {
1108                strbuf_reset(buf);
1109                strbuf_addbuf(buf, &cb.buf);
1110                retval = brace - name + 1;
1111        }
1112
1113        strbuf_release(&cb.buf);
1114        return retval;
1115}
1116
1117int get_oid_mb(const char *name, struct object_id *oid)
1118{
1119        struct commit *one, *two;
1120        struct commit_list *mbs;
1121        struct object_id oid_tmp;
1122        const char *dots;
1123        int st;
1124
1125        dots = strstr(name, "...");
1126        if (!dots)
1127                return get_oid(name, oid);
1128        if (dots == name)
1129                st = get_oid("HEAD", &oid_tmp);
1130        else {
1131                struct strbuf sb;
1132                strbuf_init(&sb, dots - name);
1133                strbuf_add(&sb, name, dots - name);
1134                st = get_sha1_committish(sb.buf, oid_tmp.hash);
1135                strbuf_release(&sb);
1136        }
1137        if (st)
1138                return st;
1139        one = lookup_commit_reference_gently(oid_tmp.hash, 0);
1140        if (!one)
1141                return -1;
1142
1143        if (get_sha1_committish(dots[3] ? (dots + 3) : "HEAD", oid_tmp.hash))
1144                return -1;
1145        two = lookup_commit_reference_gently(oid_tmp.hash, 0);
1146        if (!two)
1147                return -1;
1148        mbs = get_merge_bases(one, two);
1149        if (!mbs || mbs->next)
1150                st = -1;
1151        else {
1152                st = 0;
1153                oidcpy(oid, &mbs->item->object.oid);
1154        }
1155        free_commit_list(mbs);
1156        return st;
1157}
1158
1159/* parse @something syntax, when 'something' is not {.*} */
1160static int interpret_empty_at(const char *name, int namelen, int len, struct strbuf *buf)
1161{
1162        const char *next;
1163
1164        if (len || name[1] == '{')
1165                return -1;
1166
1167        /* make sure it's a single @, or @@{.*}, not @foo */
1168        next = memchr(name + len + 1, '@', namelen - len - 1);
1169        if (next && next[1] != '{')
1170                return -1;
1171        if (!next)
1172                next = name + namelen;
1173        if (next != name + 1)
1174                return -1;
1175
1176        strbuf_reset(buf);
1177        strbuf_add(buf, "HEAD", 4);
1178        return 1;
1179}
1180
1181static int reinterpret(const char *name, int namelen, int len,
1182                       struct strbuf *buf, unsigned allowed)
1183{
1184        /* we have extra data, which might need further processing */
1185        struct strbuf tmp = STRBUF_INIT;
1186        int used = buf->len;
1187        int ret;
1188
1189        strbuf_add(buf, name + len, namelen - len);
1190        ret = interpret_branch_name(buf->buf, buf->len, &tmp, allowed);
1191        /* that data was not interpreted, remove our cruft */
1192        if (ret < 0) {
1193                strbuf_setlen(buf, used);
1194                return len;
1195        }
1196        strbuf_reset(buf);
1197        strbuf_addbuf(buf, &tmp);
1198        strbuf_release(&tmp);
1199        /* tweak for size of {-N} versus expanded ref name */
1200        return ret - used + len;
1201}
1202
1203static void set_shortened_ref(struct strbuf *buf, const char *ref)
1204{
1205        char *s = shorten_unambiguous_ref(ref, 0);
1206        strbuf_reset(buf);
1207        strbuf_addstr(buf, s);
1208        free(s);
1209}
1210
1211static int branch_interpret_allowed(const char *refname, unsigned allowed)
1212{
1213        if (!allowed)
1214                return 1;
1215
1216        if ((allowed & INTERPRET_BRANCH_LOCAL) &&
1217            starts_with(refname, "refs/heads/"))
1218                return 1;
1219        if ((allowed & INTERPRET_BRANCH_REMOTE) &&
1220            starts_with(refname, "refs/remotes/"))
1221                return 1;
1222
1223        return 0;
1224}
1225
1226static int interpret_branch_mark(const char *name, int namelen,
1227                                 int at, struct strbuf *buf,
1228                                 int (*get_mark)(const char *, int),
1229                                 const char *(*get_data)(struct branch *,
1230                                                         struct strbuf *),
1231                                 unsigned allowed)
1232{
1233        int len;
1234        struct branch *branch;
1235        struct strbuf err = STRBUF_INIT;
1236        const char *value;
1237
1238        len = get_mark(name + at, namelen - at);
1239        if (!len)
1240                return -1;
1241
1242        if (memchr(name, ':', at))
1243                return -1;
1244
1245        if (at) {
1246                char *name_str = xmemdupz(name, at);
1247                branch = branch_get(name_str);
1248                free(name_str);
1249        } else
1250                branch = branch_get(NULL);
1251
1252        value = get_data(branch, &err);
1253        if (!value)
1254                die("%s", err.buf);
1255
1256        if (!branch_interpret_allowed(value, allowed))
1257                return -1;
1258
1259        set_shortened_ref(buf, value);
1260        return len + at;
1261}
1262
1263int interpret_branch_name(const char *name, int namelen, struct strbuf *buf,
1264                          unsigned allowed)
1265{
1266        char *at;
1267        const char *start;
1268        int len;
1269
1270        if (!namelen)
1271                namelen = strlen(name);
1272
1273        if (!allowed || (allowed & INTERPRET_BRANCH_LOCAL)) {
1274                len = interpret_nth_prior_checkout(name, namelen, buf);
1275                if (!len) {
1276                        return len; /* syntax Ok, not enough switches */
1277                } else if (len > 0) {
1278                        if (len == namelen)
1279                                return len; /* consumed all */
1280                        else
1281                                return reinterpret(name, namelen, len, buf, allowed);
1282                }
1283        }
1284
1285        for (start = name;
1286             (at = memchr(start, '@', namelen - (start - name)));
1287             start = at + 1) {
1288
1289                if (!allowed || (allowed & INTERPRET_BRANCH_HEAD)) {
1290                        len = interpret_empty_at(name, namelen, at - name, buf);
1291                        if (len > 0)
1292                                return reinterpret(name, namelen, len, buf,
1293                                                   allowed);
1294                }
1295
1296                len = interpret_branch_mark(name, namelen, at - name, buf,
1297                                            upstream_mark, branch_get_upstream,
1298                                            allowed);
1299                if (len > 0)
1300                        return len;
1301
1302                len = interpret_branch_mark(name, namelen, at - name, buf,
1303                                            push_mark, branch_get_push,
1304                                            allowed);
1305                if (len > 0)
1306                        return len;
1307        }
1308
1309        return -1;
1310}
1311
1312void strbuf_branchname(struct strbuf *sb, const char *name, unsigned allowed)
1313{
1314        int len = strlen(name);
1315        int used = interpret_branch_name(name, len, sb, allowed);
1316
1317        if (used < 0)
1318                used = 0;
1319        strbuf_add(sb, name + used, len - used);
1320}
1321
1322int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
1323{
1324        strbuf_branchname(sb, name, INTERPRET_BRANCH_LOCAL);
1325        if (name[0] == '-')
1326                return -1;
1327        strbuf_splice(sb, 0, 0, "refs/heads/", 11);
1328        return check_refname_format(sb->buf, 0);
1329}
1330
1331/*
1332 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
1333 * notably "xyz^" for "parent of xyz"
1334 */
1335int get_sha1(const char *name, unsigned char *sha1)
1336{
1337        struct object_context unused;
1338        return get_sha1_with_context(name, 0, sha1, &unused);
1339}
1340
1341/*
1342 * This is like "get_sha1()", but for struct object_id.
1343 */
1344int get_oid(const char *name, struct object_id *oid)
1345{
1346        return get_sha1(name, oid->hash);
1347}
1348
1349
1350/*
1351 * Many callers know that the user meant to name a commit-ish by
1352 * syntactical positions where the object name appears.  Calling this
1353 * function allows the machinery to disambiguate shorter-than-unique
1354 * abbreviated object names between commit-ish and others.
1355 *
1356 * Note that this does NOT error out when the named object is not a
1357 * commit-ish. It is merely to give a hint to the disambiguation
1358 * machinery.
1359 */
1360int get_sha1_committish(const char *name, unsigned char *sha1)
1361{
1362        struct object_context unused;
1363        return get_sha1_with_context(name, GET_SHA1_COMMITTISH,
1364                                     sha1, &unused);
1365}
1366
1367int get_sha1_treeish(const char *name, unsigned char *sha1)
1368{
1369        struct object_context unused;
1370        return get_sha1_with_context(name, GET_SHA1_TREEISH,
1371                                     sha1, &unused);
1372}
1373
1374int get_sha1_commit(const char *name, unsigned char *sha1)
1375{
1376        struct object_context unused;
1377        return get_sha1_with_context(name, GET_SHA1_COMMIT,
1378                                     sha1, &unused);
1379}
1380
1381int get_sha1_tree(const char *name, unsigned char *sha1)
1382{
1383        struct object_context unused;
1384        return get_sha1_with_context(name, GET_SHA1_TREE,
1385                                     sha1, &unused);
1386}
1387
1388int get_sha1_blob(const char *name, unsigned char *sha1)
1389{
1390        struct object_context unused;
1391        return get_sha1_with_context(name, GET_SHA1_BLOB,
1392                                     sha1, &unused);
1393}
1394
1395/* Must be called only when object_name:filename doesn't exist. */
1396static void diagnose_invalid_sha1_path(const char *prefix,
1397                                       const char *filename,
1398                                       const unsigned char *tree_sha1,
1399                                       const char *object_name,
1400                                       int object_name_len)
1401{
1402        unsigned char sha1[20];
1403        unsigned mode;
1404
1405        if (!prefix)
1406                prefix = "";
1407
1408        if (file_exists(filename))
1409                die("Path '%s' exists on disk, but not in '%.*s'.",
1410                    filename, object_name_len, object_name);
1411        if (errno == ENOENT || errno == ENOTDIR) {
1412                char *fullname = xstrfmt("%s%s", prefix, filename);
1413
1414                if (!get_tree_entry(tree_sha1, fullname,
1415                                    sha1, &mode)) {
1416                        die("Path '%s' exists, but not '%s'.\n"
1417                            "Did you mean '%.*s:%s' aka '%.*s:./%s'?",
1418                            fullname,
1419                            filename,
1420                            object_name_len, object_name,
1421                            fullname,
1422                            object_name_len, object_name,
1423                            filename);
1424                }
1425                die("Path '%s' does not exist in '%.*s'",
1426                    filename, object_name_len, object_name);
1427        }
1428}
1429
1430/* Must be called only when :stage:filename doesn't exist. */
1431static void diagnose_invalid_index_path(int stage,
1432                                        const char *prefix,
1433                                        const char *filename)
1434{
1435        const struct cache_entry *ce;
1436        int pos;
1437        unsigned namelen = strlen(filename);
1438        struct strbuf fullname = STRBUF_INIT;
1439
1440        if (!prefix)
1441                prefix = "";
1442
1443        /* Wrong stage number? */
1444        pos = cache_name_pos(filename, namelen);
1445        if (pos < 0)
1446                pos = -pos - 1;
1447        if (pos < active_nr) {
1448                ce = active_cache[pos];
1449                if (ce_namelen(ce) == namelen &&
1450                    !memcmp(ce->name, filename, namelen))
1451                        die("Path '%s' is in the index, but not at stage %d.\n"
1452                            "Did you mean ':%d:%s'?",
1453                            filename, stage,
1454                            ce_stage(ce), filename);
1455        }
1456
1457        /* Confusion between relative and absolute filenames? */
1458        strbuf_addstr(&fullname, prefix);
1459        strbuf_addstr(&fullname, filename);
1460        pos = cache_name_pos(fullname.buf, fullname.len);
1461        if (pos < 0)
1462                pos = -pos - 1;
1463        if (pos < active_nr) {
1464                ce = active_cache[pos];
1465                if (ce_namelen(ce) == fullname.len &&
1466                    !memcmp(ce->name, fullname.buf, fullname.len))
1467                        die("Path '%s' is in the index, but not '%s'.\n"
1468                            "Did you mean ':%d:%s' aka ':%d:./%s'?",
1469                            fullname.buf, filename,
1470                            ce_stage(ce), fullname.buf,
1471                            ce_stage(ce), filename);
1472        }
1473
1474        if (file_exists(filename))
1475                die("Path '%s' exists on disk, but not in the index.", filename);
1476        if (errno == ENOENT || errno == ENOTDIR)
1477                die("Path '%s' does not exist (neither on disk nor in the index).",
1478                    filename);
1479
1480        strbuf_release(&fullname);
1481}
1482
1483
1484static char *resolve_relative_path(const char *rel)
1485{
1486        if (!starts_with(rel, "./") && !starts_with(rel, "../"))
1487                return NULL;
1488
1489        if (!is_inside_work_tree())
1490                die("relative path syntax can't be used outside working tree.");
1491
1492        /* die() inside prefix_path() if resolved path is outside worktree */
1493        return prefix_path(startup_info->prefix,
1494                           startup_info->prefix ? strlen(startup_info->prefix) : 0,
1495                           rel);
1496}
1497
1498static int get_sha1_with_context_1(const char *name,
1499                                   unsigned flags,
1500                                   const char *prefix,
1501                                   unsigned char *sha1,
1502                                   struct object_context *oc)
1503{
1504        int ret, bracket_depth;
1505        int namelen = strlen(name);
1506        const char *cp;
1507        int only_to_die = flags & GET_SHA1_ONLY_TO_DIE;
1508
1509        if (only_to_die)
1510                flags |= GET_SHA1_QUIETLY;
1511
1512        memset(oc, 0, sizeof(*oc));
1513        oc->mode = S_IFINVALID;
1514        ret = get_sha1_1(name, namelen, sha1, flags);
1515        if (!ret)
1516                return ret;
1517        /*
1518         * sha1:path --> object name of path in ent sha1
1519         * :path -> object name of absolute path in index
1520         * :./path -> object name of path relative to cwd in index
1521         * :[0-3]:path -> object name of path in index at stage
1522         * :/foo -> recent commit matching foo
1523         */
1524        if (name[0] == ':') {
1525                int stage = 0;
1526                const struct cache_entry *ce;
1527                char *new_path = NULL;
1528                int pos;
1529                if (!only_to_die && namelen > 2 && name[1] == '/') {
1530                        struct commit_list *list = NULL;
1531
1532                        for_each_ref(handle_one_ref, &list);
1533                        commit_list_sort_by_date(&list);
1534                        return get_sha1_oneline(name + 2, sha1, list);
1535                }
1536                if (namelen < 3 ||
1537                    name[2] != ':' ||
1538                    name[1] < '0' || '3' < name[1])
1539                        cp = name + 1;
1540                else {
1541                        stage = name[1] - '0';
1542                        cp = name + 3;
1543                }
1544                new_path = resolve_relative_path(cp);
1545                if (!new_path) {
1546                        namelen = namelen - (cp - name);
1547                } else {
1548                        cp = new_path;
1549                        namelen = strlen(cp);
1550                }
1551
1552                strlcpy(oc->path, cp, sizeof(oc->path));
1553
1554                if (!active_cache)
1555                        read_cache();
1556                pos = cache_name_pos(cp, namelen);
1557                if (pos < 0)
1558                        pos = -pos - 1;
1559                while (pos < active_nr) {
1560                        ce = active_cache[pos];
1561                        if (ce_namelen(ce) != namelen ||
1562                            memcmp(ce->name, cp, namelen))
1563                                break;
1564                        if (ce_stage(ce) == stage) {
1565                                hashcpy(sha1, ce->oid.hash);
1566                                oc->mode = ce->ce_mode;
1567                                free(new_path);
1568                                return 0;
1569                        }
1570                        pos++;
1571                }
1572                if (only_to_die && name[1] && name[1] != '/')
1573                        diagnose_invalid_index_path(stage, prefix, cp);
1574                free(new_path);
1575                return -1;
1576        }
1577        for (cp = name, bracket_depth = 0; *cp; cp++) {
1578                if (*cp == '{')
1579                        bracket_depth++;
1580                else if (bracket_depth && *cp == '}')
1581                        bracket_depth--;
1582                else if (!bracket_depth && *cp == ':')
1583                        break;
1584        }
1585        if (*cp == ':') {
1586                unsigned char tree_sha1[20];
1587                int len = cp - name;
1588                unsigned sub_flags = flags;
1589
1590                sub_flags &= ~GET_SHA1_DISAMBIGUATORS;
1591                sub_flags |= GET_SHA1_TREEISH;
1592
1593                if (!get_sha1_1(name, len, tree_sha1, sub_flags)) {
1594                        const char *filename = cp+1;
1595                        char *new_filename = NULL;
1596
1597                        new_filename = resolve_relative_path(filename);
1598                        if (new_filename)
1599                                filename = new_filename;
1600                        if (flags & GET_SHA1_FOLLOW_SYMLINKS) {
1601                                ret = get_tree_entry_follow_symlinks(tree_sha1,
1602                                        filename, sha1, &oc->symlink_path,
1603                                        &oc->mode);
1604                        } else {
1605                                ret = get_tree_entry(tree_sha1, filename,
1606                                                     sha1, &oc->mode);
1607                                if (ret && only_to_die) {
1608                                        diagnose_invalid_sha1_path(prefix,
1609                                                                   filename,
1610                                                                   tree_sha1,
1611                                                                   name, len);
1612                                }
1613                        }
1614                        hashcpy(oc->tree, tree_sha1);
1615                        strlcpy(oc->path, filename, sizeof(oc->path));
1616
1617                        free(new_filename);
1618                        return ret;
1619                } else {
1620                        if (only_to_die)
1621                                die("Invalid object name '%.*s'.", len, name);
1622                }
1623        }
1624        return ret;
1625}
1626
1627/*
1628 * Call this function when you know "name" given by the end user must
1629 * name an object but it doesn't; the function _may_ die with a better
1630 * diagnostic message than "no such object 'name'", e.g. "Path 'doc' does not
1631 * exist in 'HEAD'" when given "HEAD:doc", or it may return in which case
1632 * you have a chance to diagnose the error further.
1633 */
1634void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
1635{
1636        struct object_context oc;
1637        unsigned char sha1[20];
1638        get_sha1_with_context_1(name, GET_SHA1_ONLY_TO_DIE, prefix, sha1, &oc);
1639}
1640
1641int get_sha1_with_context(const char *str, unsigned flags, unsigned char *sha1, struct object_context *orc)
1642{
1643        if (flags & GET_SHA1_FOLLOW_SYMLINKS && flags & GET_SHA1_ONLY_TO_DIE)
1644                die("BUG: incompatible flags for get_sha1_with_context");
1645        return get_sha1_with_context_1(str, flags, NULL, sha1, orc);
1646}