sha1_name.con commit sha1_name: remove unnecessary braces (b5f769a)
   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
  10static int get_sha1_oneline(const char *, unsigned char *, struct commit_list *);
  11
  12typedef int (*disambiguate_hint_fn)(const unsigned char *, void *);
  13
  14struct disambiguate_state {
  15        disambiguate_hint_fn fn;
  16        void *cb_data;
  17        unsigned char candidate[20];
  18        unsigned candidate_exists:1;
  19        unsigned candidate_checked:1;
  20        unsigned candidate_ok:1;
  21        unsigned disambiguate_fn_used:1;
  22        unsigned ambiguous:1;
  23        unsigned always_call_fn:1;
  24};
  25
  26static void update_candidates(struct disambiguate_state *ds, const unsigned char *current)
  27{
  28        if (ds->always_call_fn) {
  29                ds->ambiguous = ds->fn(current, ds->cb_data) ? 1 : 0;
  30                return;
  31        }
  32        if (!ds->candidate_exists) {
  33                /* this is the first candidate */
  34                hashcpy(ds->candidate, current);
  35                ds->candidate_exists = 1;
  36                return;
  37        } else if (!hashcmp(ds->candidate, current)) {
  38                /* the same as what we already have seen */
  39                return;
  40        }
  41
  42        if (!ds->fn) {
  43                /* cannot disambiguate between ds->candidate and current */
  44                ds->ambiguous = 1;
  45                return;
  46        }
  47
  48        if (!ds->candidate_checked) {
  49                ds->candidate_ok = ds->fn(ds->candidate, ds->cb_data);
  50                ds->disambiguate_fn_used = 1;
  51                ds->candidate_checked = 1;
  52        }
  53
  54        if (!ds->candidate_ok) {
  55                /* discard the candidate; we know it does not satisify fn */
  56                hashcpy(ds->candidate, current);
  57                ds->candidate_checked = 0;
  58                return;
  59        }
  60
  61        /* if we reach this point, we know ds->candidate satisfies fn */
  62        if (ds->fn(current, ds->cb_data)) {
  63                /*
  64                 * if both current and candidate satisfy fn, we cannot
  65                 * disambiguate.
  66                 */
  67                ds->candidate_ok = 0;
  68                ds->ambiguous = 1;
  69        }
  70
  71        /* otherwise, current can be discarded and candidate is still good */
  72}
  73
  74static void find_short_object_filename(int len, const char *hex_pfx, struct disambiguate_state *ds)
  75{
  76        struct alternate_object_database *alt;
  77        char hex[40];
  78        static struct alternate_object_database *fakeent;
  79
  80        if (!fakeent) {
  81                /*
  82                 * Create a "fake" alternate object database that
  83                 * points to our own object database, to make it
  84                 * easier to get a temporary working space in
  85                 * alt->name/alt->base while iterating over the
  86                 * object databases including our own.
  87                 */
  88                const char *objdir = get_object_directory();
  89                int objdir_len = strlen(objdir);
  90                int entlen = objdir_len + 43;
  91                fakeent = xmalloc(sizeof(*fakeent) + entlen);
  92                memcpy(fakeent->base, objdir, objdir_len);
  93                fakeent->name = fakeent->base + objdir_len + 1;
  94                fakeent->name[-1] = '/';
  95        }
  96        fakeent->next = alt_odb_list;
  97
  98        sprintf(hex, "%.2s", hex_pfx);
  99        for (alt = fakeent; alt && !ds->ambiguous; alt = alt->next) {
 100                struct dirent *de;
 101                DIR *dir;
 102                sprintf(alt->name, "%.2s/", hex_pfx);
 103                dir = opendir(alt->base);
 104                if (!dir)
 105                        continue;
 106
 107                while (!ds->ambiguous && (de = readdir(dir)) != NULL) {
 108                        unsigned char sha1[20];
 109
 110                        if (strlen(de->d_name) != 38)
 111                                continue;
 112                        if (memcmp(de->d_name, hex_pfx + 2, len - 2))
 113                                continue;
 114                        memcpy(hex + 2, de->d_name, 38);
 115                        if (!get_sha1_hex(hex, sha1))
 116                                update_candidates(ds, sha1);
 117                }
 118                closedir(dir);
 119        }
 120}
 121
 122static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
 123{
 124        do {
 125                if (*a != *b)
 126                        return 0;
 127                a++;
 128                b++;
 129                len -= 2;
 130        } while (len > 1);
 131        if (len)
 132                if ((*a ^ *b) & 0xf0)
 133                        return 0;
 134        return 1;
 135}
 136
 137static void unique_in_pack(int len,
 138                          const unsigned char *bin_pfx,
 139                           struct packed_git *p,
 140                           struct disambiguate_state *ds)
 141{
 142        uint32_t num, last, i, first = 0;
 143        const unsigned char *current = NULL;
 144
 145        open_pack_index(p);
 146        num = p->num_objects;
 147        last = num;
 148        while (first < last) {
 149                uint32_t mid = (first + last) / 2;
 150                const unsigned char *current;
 151                int cmp;
 152
 153                current = nth_packed_object_sha1(p, mid);
 154                cmp = hashcmp(bin_pfx, current);
 155                if (!cmp) {
 156                        first = mid;
 157                        break;
 158                }
 159                if (cmp > 0) {
 160                        first = mid+1;
 161                        continue;
 162                }
 163                last = mid;
 164        }
 165
 166        /*
 167         * At this point, "first" is the location of the lowest object
 168         * with an object name that could match "bin_pfx".  See if we have
 169         * 0, 1 or more objects that actually match(es).
 170         */
 171        for (i = first; i < num && !ds->ambiguous; i++) {
 172                current = nth_packed_object_sha1(p, i);
 173                if (!match_sha(len, bin_pfx, current))
 174                        break;
 175                update_candidates(ds, current);
 176        }
 177}
 178
 179static void find_short_packed_object(int len, const unsigned char *bin_pfx,
 180                                     struct disambiguate_state *ds)
 181{
 182        struct packed_git *p;
 183
 184        prepare_packed_git();
 185        for (p = packed_git; p && !ds->ambiguous; p = p->next)
 186                unique_in_pack(len, bin_pfx, p, ds);
 187}
 188
 189#define SHORT_NAME_NOT_FOUND (-1)
 190#define SHORT_NAME_AMBIGUOUS (-2)
 191
 192static int finish_object_disambiguation(struct disambiguate_state *ds,
 193                                        unsigned char *sha1)
 194{
 195        if (ds->ambiguous)
 196                return SHORT_NAME_AMBIGUOUS;
 197
 198        if (!ds->candidate_exists)
 199                return SHORT_NAME_NOT_FOUND;
 200
 201        if (!ds->candidate_checked)
 202                /*
 203                 * If this is the only candidate, there is no point
 204                 * calling the disambiguation hint callback.
 205                 *
 206                 * On the other hand, if the current candidate
 207                 * replaced an earlier candidate that did _not_ pass
 208                 * the disambiguation hint callback, then we do have
 209                 * more than one objects that match the short name
 210                 * given, so we should make sure this one matches;
 211                 * otherwise, if we discovered this one and the one
 212                 * that we previously discarded in the reverse order,
 213                 * we would end up showing different results in the
 214                 * same repository!
 215                 */
 216                ds->candidate_ok = (!ds->disambiguate_fn_used ||
 217                                    ds->fn(ds->candidate, ds->cb_data));
 218
 219        if (!ds->candidate_ok)
 220                return SHORT_NAME_AMBIGUOUS;
 221
 222        hashcpy(sha1, ds->candidate);
 223        return 0;
 224}
 225
 226static int disambiguate_commit_only(const unsigned char *sha1, void *cb_data_unused)
 227{
 228        int kind = sha1_object_info(sha1, NULL);
 229        return kind == OBJ_COMMIT;
 230}
 231
 232static int disambiguate_committish_only(const unsigned char *sha1, void *cb_data_unused)
 233{
 234        struct object *obj;
 235        int kind;
 236
 237        kind = sha1_object_info(sha1, NULL);
 238        if (kind == OBJ_COMMIT)
 239                return 1;
 240        if (kind != OBJ_TAG)
 241                return 0;
 242
 243        /* We need to do this the hard way... */
 244        obj = deref_tag(lookup_object(sha1), NULL, 0);
 245        if (obj && obj->type == OBJ_COMMIT)
 246                return 1;
 247        return 0;
 248}
 249
 250static int disambiguate_tree_only(const unsigned char *sha1, void *cb_data_unused)
 251{
 252        int kind = sha1_object_info(sha1, NULL);
 253        return kind == OBJ_TREE;
 254}
 255
 256static int disambiguate_treeish_only(const unsigned char *sha1, void *cb_data_unused)
 257{
 258        struct object *obj;
 259        int kind;
 260
 261        kind = sha1_object_info(sha1, NULL);
 262        if (kind == OBJ_TREE || kind == OBJ_COMMIT)
 263                return 1;
 264        if (kind != OBJ_TAG)
 265                return 0;
 266
 267        /* We need to do this the hard way... */
 268        obj = deref_tag(lookup_object(sha1), NULL, 0);
 269        if (obj && (obj->type == OBJ_TREE || obj->type == OBJ_COMMIT))
 270                return 1;
 271        return 0;
 272}
 273
 274static int disambiguate_blob_only(const unsigned char *sha1, void *cb_data_unused)
 275{
 276        int kind = sha1_object_info(sha1, NULL);
 277        return kind == OBJ_BLOB;
 278}
 279
 280static int prepare_prefixes(const char *name, int len,
 281                            unsigned char *bin_pfx,
 282                            char *hex_pfx)
 283{
 284        int i;
 285
 286        hashclr(bin_pfx);
 287        memset(hex_pfx, 'x', 40);
 288        for (i = 0; i < len ;i++) {
 289                unsigned char c = name[i];
 290                unsigned char val;
 291                if (c >= '0' && c <= '9')
 292                        val = c - '0';
 293                else if (c >= 'a' && c <= 'f')
 294                        val = c - 'a' + 10;
 295                else if (c >= 'A' && c <='F') {
 296                        val = c - 'A' + 10;
 297                        c -= 'A' - 'a';
 298                }
 299                else
 300                        return -1;
 301                hex_pfx[i] = c;
 302                if (!(i & 1))
 303                        val <<= 4;
 304                bin_pfx[i >> 1] |= val;
 305        }
 306        return 0;
 307}
 308
 309static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 310                          unsigned flags)
 311{
 312        int status;
 313        char hex_pfx[40];
 314        unsigned char bin_pfx[20];
 315        struct disambiguate_state ds;
 316        int quietly = !!(flags & GET_SHA1_QUIETLY);
 317
 318        if (len < MINIMUM_ABBREV || len > 40)
 319                return -1;
 320        if (prepare_prefixes(name, len, bin_pfx, hex_pfx) < 0)
 321                return -1;
 322
 323        prepare_alt_odb();
 324
 325        memset(&ds, 0, sizeof(ds));
 326        if (flags & GET_SHA1_COMMIT)
 327                ds.fn = disambiguate_commit_only;
 328        else if (flags & GET_SHA1_COMMITTISH)
 329                ds.fn = disambiguate_committish_only;
 330        else if (flags & GET_SHA1_TREE)
 331                ds.fn = disambiguate_tree_only;
 332        else if (flags & GET_SHA1_TREEISH)
 333                ds.fn = disambiguate_treeish_only;
 334        else if (flags & GET_SHA1_BLOB)
 335                ds.fn = disambiguate_blob_only;
 336
 337        find_short_object_filename(len, hex_pfx, &ds);
 338        find_short_packed_object(len, bin_pfx, &ds);
 339        status = finish_object_disambiguation(&ds, sha1);
 340
 341        if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
 342                return error("short SHA1 %.*s is ambiguous.", len, hex_pfx);
 343        return status;
 344}
 345
 346
 347int for_each_abbrev(const char *prefix, each_abbrev_fn fn, void *cb_data)
 348{
 349        char hex_pfx[40];
 350        unsigned char bin_pfx[20];
 351        struct disambiguate_state ds;
 352        int len = strlen(prefix);
 353
 354        if (len < MINIMUM_ABBREV || len > 40)
 355                return -1;
 356        if (prepare_prefixes(prefix, len, bin_pfx, hex_pfx) < 0)
 357                return -1;
 358
 359        prepare_alt_odb();
 360
 361        memset(&ds, 0, sizeof(ds));
 362        ds.always_call_fn = 1;
 363        ds.cb_data = cb_data;
 364        ds.fn = fn;
 365
 366        find_short_object_filename(len, hex_pfx, &ds);
 367        find_short_packed_object(len, bin_pfx, &ds);
 368        return ds.ambiguous;
 369}
 370
 371const char *find_unique_abbrev(const unsigned char *sha1, int len)
 372{
 373        int status, exists;
 374        static char hex[41];
 375
 376        exists = has_sha1_file(sha1);
 377        memcpy(hex, sha1_to_hex(sha1), 40);
 378        if (len == 40 || !len)
 379                return hex;
 380        while (len < 40) {
 381                unsigned char sha1_ret[20];
 382                status = get_short_sha1(hex, len, sha1_ret, GET_SHA1_QUIETLY);
 383                if (exists
 384                    ? !status
 385                    : status == SHORT_NAME_NOT_FOUND) {
 386                        hex[len] = 0;
 387                        return hex;
 388                }
 389                len++;
 390        }
 391        return hex;
 392}
 393
 394static int ambiguous_path(const char *path, int len)
 395{
 396        int slash = 1;
 397        int cnt;
 398
 399        for (cnt = 0; cnt < len; cnt++) {
 400                switch (*path++) {
 401                case '\0':
 402                        break;
 403                case '/':
 404                        if (slash)
 405                                break;
 406                        slash = 1;
 407                        continue;
 408                case '.':
 409                        continue;
 410                default:
 411                        slash = 0;
 412                        continue;
 413                }
 414                break;
 415        }
 416        return slash;
 417}
 418
 419static inline int upstream_mark(const char *string, int len)
 420{
 421        const char *suffix[] = { "@{upstream}", "@{u}" };
 422        int i;
 423
 424        for (i = 0; i < ARRAY_SIZE(suffix); i++) {
 425                int suffix_len = strlen(suffix[i]);
 426                if (suffix_len <= len
 427                    && !memcmp(string, suffix[i], suffix_len))
 428                        return suffix_len;
 429        }
 430        return 0;
 431}
 432
 433static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags);
 434
 435static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 436{
 437        static const char *warn_msg = "refname '%.*s' is ambiguous.";
 438        char *real_ref = NULL;
 439        int refs_found = 0;
 440        int at, reflog_len;
 441
 442        if (len == 40 && !get_sha1_hex(str, sha1))
 443                return 0;
 444
 445        /* basic@{time or number or -number} format to query ref-log */
 446        reflog_len = at = 0;
 447        if (len && str[len-1] == '}') {
 448                for (at = len-2; at >= 0; at--) {
 449                        if (str[at] == '@' && str[at+1] == '{') {
 450                                if (!upstream_mark(str + at, len - at)) {
 451                                        reflog_len = (len-1) - (at+2);
 452                                        len = at;
 453                                }
 454                                break;
 455                        }
 456                }
 457        }
 458
 459        /* Accept only unambiguous ref paths. */
 460        if (len && ambiguous_path(str, len))
 461                return -1;
 462
 463        if (!len && reflog_len) {
 464                struct strbuf buf = STRBUF_INIT;
 465                int ret;
 466                /* try the @{-N} syntax for n-th checkout */
 467                ret = interpret_branch_name(str, &buf);
 468                if (ret > 0)
 469                        /* substitute this branch name and restart */
 470                        return get_sha1_1(buf.buf, buf.len, sha1, 0);
 471                else if (ret == 0)
 472                        return -1;
 473                /* allow "@{...}" to mean the current branch reflog */
 474                refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
 475        } else if (reflog_len)
 476                refs_found = dwim_log(str, len, sha1, &real_ref);
 477        else
 478                refs_found = dwim_ref(str, len, sha1, &real_ref);
 479
 480        if (!refs_found)
 481                return -1;
 482
 483        if (warn_ambiguous_refs && refs_found > 1)
 484                warning(warn_msg, len, str);
 485
 486        if (reflog_len) {
 487                int nth, i;
 488                unsigned long at_time;
 489                unsigned long co_time;
 490                int co_tz, co_cnt;
 491
 492                /* a @{-N} placed anywhere except the start is an error */
 493                if (str[at+2] == '-')
 494                        return -1;
 495
 496                /* Is it asking for N-th entry, or approxidate? */
 497                for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 498                        char ch = str[at+2+i];
 499                        if ('0' <= ch && ch <= '9')
 500                                nth = nth * 10 + ch - '0';
 501                        else
 502                                nth = -1;
 503                }
 504                if (100000000 <= nth) {
 505                        at_time = nth;
 506                        nth = -1;
 507                } else if (0 <= nth)
 508                        at_time = 0;
 509                else {
 510                        int errors = 0;
 511                        char *tmp = xstrndup(str + at + 2, reflog_len);
 512                        at_time = approxidate_careful(tmp, &errors);
 513                        free(tmp);
 514                        if (errors)
 515                                return -1;
 516                }
 517                if (read_ref_at(real_ref, at_time, nth, sha1, NULL,
 518                                &co_time, &co_tz, &co_cnt)) {
 519                        if (at_time)
 520                                warning("Log for '%.*s' only goes "
 521                                        "back to %s.", len, str,
 522                                        show_date(co_time, co_tz, DATE_RFC2822));
 523                        else {
 524                                free(real_ref);
 525                                die("Log for '%.*s' only has %d entries.",
 526                                    len, str, co_cnt);
 527                        }
 528                }
 529        }
 530
 531        free(real_ref);
 532        return 0;
 533}
 534
 535static int get_parent(const char *name, int len,
 536                      unsigned char *result, int idx)
 537{
 538        unsigned char sha1[20];
 539        int ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 540        struct commit *commit;
 541        struct commit_list *p;
 542
 543        if (ret)
 544                return ret;
 545        commit = lookup_commit_reference(sha1);
 546        if (!commit)
 547                return -1;
 548        if (parse_commit(commit))
 549                return -1;
 550        if (!idx) {
 551                hashcpy(result, commit->object.sha1);
 552                return 0;
 553        }
 554        p = commit->parents;
 555        while (p) {
 556                if (!--idx) {
 557                        hashcpy(result, p->item->object.sha1);
 558                        return 0;
 559                }
 560                p = p->next;
 561        }
 562        return -1;
 563}
 564
 565static int get_nth_ancestor(const char *name, int len,
 566                            unsigned char *result, int generation)
 567{
 568        unsigned char sha1[20];
 569        struct commit *commit;
 570        int ret;
 571
 572        ret = get_sha1_1(name, len, sha1, GET_SHA1_COMMITTISH);
 573        if (ret)
 574                return ret;
 575        commit = lookup_commit_reference(sha1);
 576        if (!commit)
 577                return -1;
 578
 579        while (generation--) {
 580                if (parse_commit(commit) || !commit->parents)
 581                        return -1;
 582                commit = commit->parents->item;
 583        }
 584        hashcpy(result, commit->object.sha1);
 585        return 0;
 586}
 587
 588struct object *peel_to_type(const char *name, int namelen,
 589                            struct object *o, enum object_type expected_type)
 590{
 591        if (name && !namelen)
 592                namelen = strlen(name);
 593        while (1) {
 594                if (!o || (!o->parsed && !parse_object(o->sha1)))
 595                        return NULL;
 596                if (expected_type == OBJ_ANY || o->type == expected_type)
 597                        return o;
 598                if (o->type == OBJ_TAG)
 599                        o = ((struct tag*) o)->tagged;
 600                else if (o->type == OBJ_COMMIT)
 601                        o = &(((struct commit *) o)->tree->object);
 602                else {
 603                        if (name)
 604                                error("%.*s: expected %s type, but the object "
 605                                      "dereferences to %s type",
 606                                      namelen, name, typename(expected_type),
 607                                      typename(o->type));
 608                        return NULL;
 609                }
 610        }
 611}
 612
 613static int peel_onion(const char *name, int len, unsigned char *sha1)
 614{
 615        unsigned char outer[20];
 616        const char *sp;
 617        unsigned int expected_type = 0;
 618        unsigned lookup_flags = 0;
 619        struct object *o;
 620
 621        /*
 622         * "ref^{type}" dereferences ref repeatedly until you cannot
 623         * dereference anymore, or you get an object of given type,
 624         * whichever comes first.  "ref^{}" means just dereference
 625         * tags until you get a non-tag.  "ref^0" is a shorthand for
 626         * "ref^{commit}".  "commit^{tree}" could be used to find the
 627         * top-level tree of the given commit.
 628         */
 629        if (len < 4 || name[len-1] != '}')
 630                return -1;
 631
 632        for (sp = name + len - 1; name <= sp; sp--) {
 633                int ch = *sp;
 634                if (ch == '{' && name < sp && sp[-1] == '^')
 635                        break;
 636        }
 637        if (sp <= name)
 638                return -1;
 639
 640        sp++; /* beginning of type name, or closing brace for empty */
 641        if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
 642                expected_type = OBJ_COMMIT;
 643        else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
 644                expected_type = OBJ_TREE;
 645        else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
 646                expected_type = OBJ_BLOB;
 647        else if (!prefixcmp(sp, "object}"))
 648                expected_type = OBJ_ANY;
 649        else if (sp[0] == '}')
 650                expected_type = OBJ_NONE;
 651        else if (sp[0] == '/')
 652                expected_type = OBJ_COMMIT;
 653        else
 654                return -1;
 655
 656        if (expected_type == OBJ_COMMIT)
 657                lookup_flags = GET_SHA1_COMMITTISH;
 658        else if (expected_type == OBJ_TREE)
 659                lookup_flags = GET_SHA1_TREEISH;
 660
 661        if (get_sha1_1(name, sp - name - 2, outer, lookup_flags))
 662                return -1;
 663
 664        o = parse_object(outer);
 665        if (!o)
 666                return -1;
 667        if (!expected_type) {
 668                o = deref_tag(o, name, sp - name - 2);
 669                if (!o || (!o->parsed && !parse_object(o->sha1)))
 670                        return -1;
 671                hashcpy(sha1, o->sha1);
 672                return 0;
 673        }
 674
 675        /*
 676         * At this point, the syntax look correct, so
 677         * if we do not get the needed object, we should
 678         * barf.
 679         */
 680        o = peel_to_type(name, len, o, expected_type);
 681        if (!o)
 682                return -1;
 683
 684        hashcpy(sha1, o->sha1);
 685        if (sp[0] == '/') {
 686                /* "$commit^{/foo}" */
 687                char *prefix;
 688                int ret;
 689                struct commit_list *list = NULL;
 690
 691                /*
 692                 * $commit^{/}. Some regex implementation may reject.
 693                 * We don't need regex anyway. '' pattern always matches.
 694                 */
 695                if (sp[1] == '}')
 696                        return 0;
 697
 698                prefix = xstrndup(sp + 1, name + len - 1 - (sp + 1));
 699                commit_list_insert((struct commit *)o, &list);
 700                ret = get_sha1_oneline(prefix, sha1, list);
 701                free(prefix);
 702                return ret;
 703        }
 704        return 0;
 705}
 706
 707static int get_describe_name(const char *name, int len, unsigned char *sha1)
 708{
 709        const char *cp;
 710        unsigned flags = GET_SHA1_QUIETLY | GET_SHA1_COMMIT;
 711
 712        for (cp = name + len - 1; name + 2 <= cp; cp--) {
 713                char ch = *cp;
 714                if (hexval(ch) & ~0377) {
 715                        /* We must be looking at g in "SOMETHING-g"
 716                         * for it to be describe output.
 717                         */
 718                        if (ch == 'g' && cp[-1] == '-') {
 719                                cp++;
 720                                len -= cp - name;
 721                                return get_short_sha1(cp, len, sha1, flags);
 722                        }
 723                }
 724        }
 725        return -1;
 726}
 727
 728static int get_sha1_1(const char *name, int len, unsigned char *sha1, unsigned lookup_flags)
 729{
 730        int ret, has_suffix;
 731        const char *cp;
 732
 733        /*
 734         * "name~3" is "name^^^", "name~" is "name~1", and "name^" is "name^1".
 735         */
 736        has_suffix = 0;
 737        for (cp = name + len - 1; name <= cp; cp--) {
 738                int ch = *cp;
 739                if ('0' <= ch && ch <= '9')
 740                        continue;
 741                if (ch == '~' || ch == '^')
 742                        has_suffix = ch;
 743                break;
 744        }
 745
 746        if (has_suffix) {
 747                int num = 0;
 748                int len1 = cp - name;
 749                cp++;
 750                while (cp < name + len)
 751                        num = num * 10 + *cp++ - '0';
 752                if (!num && len1 == len - 1)
 753                        num = 1;
 754                if (has_suffix == '^')
 755                        return get_parent(name, len1, sha1, num);
 756                /* else if (has_suffix == '~') -- goes without saying */
 757                return get_nth_ancestor(name, len1, sha1, num);
 758        }
 759
 760        ret = peel_onion(name, len, sha1);
 761        if (!ret)
 762                return 0;
 763
 764        ret = get_sha1_basic(name, len, sha1);
 765        if (!ret)
 766                return 0;
 767
 768        /* It could be describe output that is "SOMETHING-gXXXX" */
 769        ret = get_describe_name(name, len, sha1);
 770        if (!ret)
 771                return 0;
 772
 773        return get_short_sha1(name, len, sha1, lookup_flags);
 774}
 775
 776/*
 777 * This interprets names like ':/Initial revision of "git"' by searching
 778 * through history and returning the first commit whose message starts
 779 * the given regular expression.
 780 *
 781 * For future extension, ':/!' is reserved. If you want to match a message
 782 * beginning with a '!', you have to repeat the exclamation mark.
 783 */
 784#define ONELINE_SEEN (1u<<20)
 785
 786static int handle_one_ref(const char *path,
 787                const unsigned char *sha1, int flag, void *cb_data)
 788{
 789        struct commit_list **list = cb_data;
 790        struct object *object = parse_object(sha1);
 791        if (!object)
 792                return 0;
 793        if (object->type == OBJ_TAG) {
 794                object = deref_tag(object, path, strlen(path));
 795                if (!object)
 796                        return 0;
 797        }
 798        if (object->type != OBJ_COMMIT)
 799                return 0;
 800        commit_list_insert_by_date((struct commit *)object, list);
 801        return 0;
 802}
 803
 804static int get_sha1_oneline(const char *prefix, unsigned char *sha1,
 805                            struct commit_list *list)
 806{
 807        struct commit_list *backup = NULL, *l;
 808        int found = 0;
 809        regex_t regex;
 810
 811        if (prefix[0] == '!') {
 812                if (prefix[1] != '!')
 813                        die ("Invalid search pattern: %s", prefix);
 814                prefix++;
 815        }
 816
 817        if (regcomp(&regex, prefix, REG_EXTENDED))
 818                die("Invalid search pattern: %s", prefix);
 819
 820        for (l = list; l; l = l->next) {
 821                l->item->object.flags |= ONELINE_SEEN;
 822                commit_list_insert(l->item, &backup);
 823        }
 824        while (list) {
 825                char *p, *to_free = NULL;
 826                struct commit *commit;
 827                enum object_type type;
 828                unsigned long size;
 829                int matches;
 830
 831                commit = pop_most_recent_commit(&list, ONELINE_SEEN);
 832                if (!parse_object(commit->object.sha1))
 833                        continue;
 834                if (commit->buffer)
 835                        p = commit->buffer;
 836                else {
 837                        p = read_sha1_file(commit->object.sha1, &type, &size);
 838                        if (!p)
 839                                continue;
 840                        to_free = p;
 841                }
 842
 843                p = strstr(p, "\n\n");
 844                matches = p && !regexec(&regex, p + 2, 0, NULL, 0);
 845                free(to_free);
 846
 847                if (matches) {
 848                        hashcpy(sha1, commit->object.sha1);
 849                        found = 1;
 850                        break;
 851                }
 852        }
 853        regfree(&regex);
 854        free_commit_list(list);
 855        for (l = backup; l; l = l->next)
 856                clear_commit_marks(l->item, ONELINE_SEEN);
 857        free_commit_list(backup);
 858        return found ? 0 : -1;
 859}
 860
 861struct grab_nth_branch_switch_cbdata {
 862        int remaining;
 863        struct strbuf buf;
 864};
 865
 866static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
 867                                  const char *email, unsigned long timestamp, int tz,
 868                                  const char *message, void *cb_data)
 869{
 870        struct grab_nth_branch_switch_cbdata *cb = cb_data;
 871        const char *match = NULL, *target = NULL;
 872        size_t len;
 873
 874        if (!prefixcmp(message, "checkout: moving from ")) {
 875                match = message + strlen("checkout: moving from ");
 876                target = strstr(match, " to ");
 877        }
 878
 879        if (!match || !target)
 880                return 0;
 881        if (--(cb->remaining) == 0) {
 882                len = target - match;
 883                strbuf_reset(&cb->buf);
 884                strbuf_add(&cb->buf, match, len);
 885                return 1; /* we are done */
 886        }
 887        return 0;
 888}
 889
 890/*
 891 * Parse @{-N} syntax, return the number of characters parsed
 892 * if successful; otherwise signal an error with negative value.
 893 */
 894static int interpret_nth_prior_checkout(const char *name, struct strbuf *buf)
 895{
 896        long nth;
 897        int retval;
 898        struct grab_nth_branch_switch_cbdata cb;
 899        const char *brace;
 900        char *num_end;
 901
 902        if (name[0] != '@' || name[1] != '{' || name[2] != '-')
 903                return -1;
 904        brace = strchr(name, '}');
 905        if (!brace)
 906                return -1;
 907        nth = strtol(name + 3, &num_end, 10);
 908        if (num_end != brace)
 909                return -1;
 910        if (nth <= 0)
 911                return -1;
 912        cb.remaining = nth;
 913        strbuf_init(&cb.buf, 20);
 914
 915        retval = 0;
 916        if (0 < for_each_reflog_ent_reverse("HEAD", grab_nth_branch_switch, &cb)) {
 917                strbuf_reset(buf);
 918                strbuf_add(buf, cb.buf.buf, cb.buf.len);
 919                retval = brace - name + 1;
 920        }
 921
 922        strbuf_release(&cb.buf);
 923        return retval;
 924}
 925
 926int get_sha1_mb(const char *name, unsigned char *sha1)
 927{
 928        struct commit *one, *two;
 929        struct commit_list *mbs;
 930        unsigned char sha1_tmp[20];
 931        const char *dots;
 932        int st;
 933
 934        dots = strstr(name, "...");
 935        if (!dots)
 936                return get_sha1(name, sha1);
 937        if (dots == name)
 938                st = get_sha1("HEAD", sha1_tmp);
 939        else {
 940                struct strbuf sb;
 941                strbuf_init(&sb, dots - name);
 942                strbuf_add(&sb, name, dots - name);
 943                st = get_sha1_committish(sb.buf, sha1_tmp);
 944                strbuf_release(&sb);
 945        }
 946        if (st)
 947                return st;
 948        one = lookup_commit_reference_gently(sha1_tmp, 0);
 949        if (!one)
 950                return -1;
 951
 952        if (get_sha1_committish(dots[3] ? (dots + 3) : "HEAD", sha1_tmp))
 953                return -1;
 954        two = lookup_commit_reference_gently(sha1_tmp, 0);
 955        if (!two)
 956                return -1;
 957        mbs = get_merge_bases(one, two, 1);
 958        if (!mbs || mbs->next)
 959                st = -1;
 960        else {
 961                st = 0;
 962                hashcpy(sha1, mbs->item->object.sha1);
 963        }
 964        free_commit_list(mbs);
 965        return st;
 966}
 967
 968/*
 969 * This reads short-hand syntax that not only evaluates to a commit
 970 * object name, but also can act as if the end user spelled the name
 971 * of the branch from the command line.
 972 *
 973 * - "@{-N}" finds the name of the Nth previous branch we were on, and
 974 *   places the name of the branch in the given buf and returns the
 975 *   number of characters parsed if successful.
 976 *
 977 * - "<branch>@{upstream}" finds the name of the other ref that
 978 *   <branch> is configured to merge with (missing <branch> defaults
 979 *   to the current branch), and places the name of the branch in the
 980 *   given buf and returns the number of characters parsed if
 981 *   successful.
 982 *
 983 * If the input is not of the accepted format, it returns a negative
 984 * number to signal an error.
 985 *
 986 * If the input was ok but there are not N branch switches in the
 987 * reflog, it returns 0.
 988 */
 989int interpret_branch_name(const char *name, struct strbuf *buf)
 990{
 991        char *cp;
 992        struct branch *upstream;
 993        int namelen = strlen(name);
 994        int len = interpret_nth_prior_checkout(name, buf);
 995        int tmp_len;
 996
 997        if (!len)
 998                return len; /* syntax Ok, not enough switches */
 999        if (0 < len && len == namelen)
1000                return len; /* consumed all */
1001        else if (0 < len) {
1002                /* we have extra data, which might need further processing */
1003                struct strbuf tmp = STRBUF_INIT;
1004                int used = buf->len;
1005                int ret;
1006
1007                strbuf_add(buf, name + len, namelen - len);
1008                ret = interpret_branch_name(buf->buf, &tmp);
1009                /* that data was not interpreted, remove our cruft */
1010                if (ret < 0) {
1011                        strbuf_setlen(buf, used);
1012                        return len;
1013                }
1014                strbuf_reset(buf);
1015                strbuf_addbuf(buf, &tmp);
1016                strbuf_release(&tmp);
1017                /* tweak for size of {-N} versus expanded ref name */
1018                return ret - used + len;
1019        }
1020
1021        cp = strchr(name, '@');
1022        if (!cp)
1023                return -1;
1024        tmp_len = upstream_mark(cp, namelen - (cp - name));
1025        if (!tmp_len)
1026                return -1;
1027        len = cp + tmp_len - name;
1028        cp = xstrndup(name, cp - name);
1029        upstream = branch_get(*cp ? cp : NULL);
1030        /*
1031         * Upstream can be NULL only if cp refers to HEAD and HEAD
1032         * points to something different than a branch.
1033         */
1034        if (!upstream)
1035                return error(_("HEAD does not point to a branch"));
1036        if (!upstream->merge || !upstream->merge[0]->dst) {
1037                if (!ref_exists(upstream->refname))
1038                        return error(_("No such branch: '%s'"), cp);
1039                if (!upstream->merge)
1040                        return error(_("No upstream configured for branch '%s'"),
1041                                     upstream->name);
1042                return error(
1043                        _("Upstream branch '%s' not stored as a remote-tracking branch"),
1044                        upstream->merge[0]->src);
1045        }
1046        free(cp);
1047        cp = shorten_unambiguous_ref(upstream->merge[0]->dst, 0);
1048        strbuf_reset(buf);
1049        strbuf_addstr(buf, cp);
1050        free(cp);
1051        return len;
1052}
1053
1054int strbuf_branchname(struct strbuf *sb, const char *name)
1055{
1056        int len = strlen(name);
1057        if (interpret_branch_name(name, sb) == len)
1058                return 0;
1059        strbuf_add(sb, name, len);
1060        return len;
1061}
1062
1063int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
1064{
1065        strbuf_branchname(sb, name);
1066        if (name[0] == '-')
1067                return -1;
1068        strbuf_splice(sb, 0, 0, "refs/heads/", 11);
1069        return check_refname_format(sb->buf, 0);
1070}
1071
1072/*
1073 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
1074 * notably "xyz^" for "parent of xyz"
1075 */
1076int get_sha1(const char *name, unsigned char *sha1)
1077{
1078        struct object_context unused;
1079        return get_sha1_with_context(name, 0, sha1, &unused);
1080}
1081
1082/*
1083 * Many callers know that the user meant to name a committish by
1084 * syntactical positions where the object name appears.  Calling this
1085 * function allows the machinery to disambiguate shorter-than-unique
1086 * abbreviated object names between committish and others.
1087 *
1088 * Note that this does NOT error out when the named object is not a
1089 * committish. It is merely to give a hint to the disambiguation
1090 * machinery.
1091 */
1092int get_sha1_committish(const char *name, unsigned char *sha1)
1093{
1094        struct object_context unused;
1095        return get_sha1_with_context(name, GET_SHA1_COMMITTISH,
1096                                     sha1, &unused);
1097}
1098
1099int get_sha1_treeish(const char *name, unsigned char *sha1)
1100{
1101        struct object_context unused;
1102        return get_sha1_with_context(name, GET_SHA1_TREEISH,
1103                                     sha1, &unused);
1104}
1105
1106int get_sha1_commit(const char *name, unsigned char *sha1)
1107{
1108        struct object_context unused;
1109        return get_sha1_with_context(name, GET_SHA1_COMMIT,
1110                                     sha1, &unused);
1111}
1112
1113int get_sha1_tree(const char *name, unsigned char *sha1)
1114{
1115        struct object_context unused;
1116        return get_sha1_with_context(name, GET_SHA1_TREE,
1117                                     sha1, &unused);
1118}
1119
1120int get_sha1_blob(const char *name, unsigned char *sha1)
1121{
1122        struct object_context unused;
1123        return get_sha1_with_context(name, GET_SHA1_BLOB,
1124                                     sha1, &unused);
1125}
1126
1127/* Must be called only when object_name:filename doesn't exist. */
1128static void diagnose_invalid_sha1_path(const char *prefix,
1129                                       const char *filename,
1130                                       const unsigned char *tree_sha1,
1131                                       const char *object_name,
1132                                       int object_name_len)
1133{
1134        struct stat st;
1135        unsigned char sha1[20];
1136        unsigned mode;
1137
1138        if (!prefix)
1139                prefix = "";
1140
1141        if (!lstat(filename, &st))
1142                die("Path '%s' exists on disk, but not in '%.*s'.",
1143                    filename, object_name_len, object_name);
1144        if (errno == ENOENT || errno == ENOTDIR) {
1145                char *fullname = xmalloc(strlen(filename)
1146                                             + strlen(prefix) + 1);
1147                strcpy(fullname, prefix);
1148                strcat(fullname, filename);
1149
1150                if (!get_tree_entry(tree_sha1, fullname,
1151                                    sha1, &mode)) {
1152                        die("Path '%s' exists, but not '%s'.\n"
1153                            "Did you mean '%.*s:%s' aka '%.*s:./%s'?",
1154                            fullname,
1155                            filename,
1156                            object_name_len, object_name,
1157                            fullname,
1158                            object_name_len, object_name,
1159                            filename);
1160                }
1161                die("Path '%s' does not exist in '%.*s'",
1162                    filename, object_name_len, object_name);
1163        }
1164}
1165
1166/* Must be called only when :stage:filename doesn't exist. */
1167static void diagnose_invalid_index_path(int stage,
1168                                        const char *prefix,
1169                                        const char *filename)
1170{
1171        struct stat st;
1172        struct cache_entry *ce;
1173        int pos;
1174        unsigned namelen = strlen(filename);
1175        unsigned fullnamelen;
1176        char *fullname;
1177
1178        if (!prefix)
1179                prefix = "";
1180
1181        /* Wrong stage number? */
1182        pos = cache_name_pos(filename, namelen);
1183        if (pos < 0)
1184                pos = -pos - 1;
1185        if (pos < active_nr) {
1186                ce = active_cache[pos];
1187                if (ce_namelen(ce) == namelen &&
1188                    !memcmp(ce->name, filename, namelen))
1189                        die("Path '%s' is in the index, but not at stage %d.\n"
1190                            "Did you mean ':%d:%s'?",
1191                            filename, stage,
1192                            ce_stage(ce), filename);
1193        }
1194
1195        /* Confusion between relative and absolute filenames? */
1196        fullnamelen = namelen + strlen(prefix);
1197        fullname = xmalloc(fullnamelen + 1);
1198        strcpy(fullname, prefix);
1199        strcat(fullname, filename);
1200        pos = cache_name_pos(fullname, fullnamelen);
1201        if (pos < 0)
1202                pos = -pos - 1;
1203        if (pos < active_nr) {
1204                ce = active_cache[pos];
1205                if (ce_namelen(ce) == fullnamelen &&
1206                    !memcmp(ce->name, fullname, fullnamelen))
1207                        die("Path '%s' is in the index, but not '%s'.\n"
1208                            "Did you mean ':%d:%s' aka ':%d:./%s'?",
1209                            fullname, filename,
1210                            ce_stage(ce), fullname,
1211                            ce_stage(ce), filename);
1212        }
1213
1214        if (!lstat(filename, &st))
1215                die("Path '%s' exists on disk, but not in the index.", filename);
1216        if (errno == ENOENT || errno == ENOTDIR)
1217                die("Path '%s' does not exist (neither on disk nor in the index).",
1218                    filename);
1219
1220        free(fullname);
1221}
1222
1223
1224static char *resolve_relative_path(const char *rel)
1225{
1226        if (prefixcmp(rel, "./") && prefixcmp(rel, "../"))
1227                return NULL;
1228
1229        if (!startup_info)
1230                die("BUG: startup_info struct is not initialized.");
1231
1232        if (!is_inside_work_tree())
1233                die("relative path syntax can't be used outside working tree.");
1234
1235        /* die() inside prefix_path() if resolved path is outside worktree */
1236        return prefix_path(startup_info->prefix,
1237                           startup_info->prefix ? strlen(startup_info->prefix) : 0,
1238                           rel);
1239}
1240
1241static int get_sha1_with_context_1(const char *name,
1242                                   unsigned flags,
1243                                   const char *prefix,
1244                                   unsigned char *sha1,
1245                                   struct object_context *oc)
1246{
1247        int ret, bracket_depth;
1248        int namelen = strlen(name);
1249        const char *cp;
1250        int only_to_die = flags & GET_SHA1_ONLY_TO_DIE;
1251
1252        memset(oc, 0, sizeof(*oc));
1253        oc->mode = S_IFINVALID;
1254        ret = get_sha1_1(name, namelen, sha1, flags);
1255        if (!ret)
1256                return ret;
1257        /*
1258         * sha1:path --> object name of path in ent sha1
1259         * :path -> object name of absolute path in index
1260         * :./path -> object name of path relative to cwd in index
1261         * :[0-3]:path -> object name of path in index at stage
1262         * :/foo -> recent commit matching foo
1263         */
1264        if (name[0] == ':') {
1265                int stage = 0;
1266                struct cache_entry *ce;
1267                char *new_path = NULL;
1268                int pos;
1269                if (!only_to_die && namelen > 2 && name[1] == '/') {
1270                        struct commit_list *list = NULL;
1271                        for_each_ref(handle_one_ref, &list);
1272                        return get_sha1_oneline(name + 2, sha1, list);
1273                }
1274                if (namelen < 3 ||
1275                    name[2] != ':' ||
1276                    name[1] < '0' || '3' < name[1])
1277                        cp = name + 1;
1278                else {
1279                        stage = name[1] - '0';
1280                        cp = name + 3;
1281                }
1282                new_path = resolve_relative_path(cp);
1283                if (!new_path) {
1284                        namelen = namelen - (cp - name);
1285                } else {
1286                        cp = new_path;
1287                        namelen = strlen(cp);
1288                }
1289
1290                strncpy(oc->path, cp,
1291                        sizeof(oc->path));
1292                oc->path[sizeof(oc->path)-1] = '\0';
1293
1294                if (!active_cache)
1295                        read_cache();
1296                pos = cache_name_pos(cp, namelen);
1297                if (pos < 0)
1298                        pos = -pos - 1;
1299                while (pos < active_nr) {
1300                        ce = active_cache[pos];
1301                        if (ce_namelen(ce) != namelen ||
1302                            memcmp(ce->name, cp, namelen))
1303                                break;
1304                        if (ce_stage(ce) == stage) {
1305                                hashcpy(sha1, ce->sha1);
1306                                oc->mode = ce->ce_mode;
1307                                free(new_path);
1308                                return 0;
1309                        }
1310                        pos++;
1311                }
1312                if (only_to_die && name[1] && name[1] != '/')
1313                        diagnose_invalid_index_path(stage, prefix, cp);
1314                free(new_path);
1315                return -1;
1316        }
1317        for (cp = name, bracket_depth = 0; *cp; cp++) {
1318                if (*cp == '{')
1319                        bracket_depth++;
1320                else if (bracket_depth && *cp == '}')
1321                        bracket_depth--;
1322                else if (!bracket_depth && *cp == ':')
1323                        break;
1324        }
1325        if (*cp == ':') {
1326                unsigned char tree_sha1[20];
1327                int len = cp - name;
1328                if (!get_sha1_1(name, len, tree_sha1, GET_SHA1_TREEISH)) {
1329                        const char *filename = cp+1;
1330                        char *new_filename = NULL;
1331
1332                        new_filename = resolve_relative_path(filename);
1333                        if (new_filename)
1334                                filename = new_filename;
1335                        ret = get_tree_entry(tree_sha1, filename, sha1, &oc->mode);
1336                        if (ret && only_to_die) {
1337                                diagnose_invalid_sha1_path(prefix, filename,
1338                                                           tree_sha1,
1339                                                           name, len);
1340                        }
1341                        hashcpy(oc->tree, tree_sha1);
1342                        strncpy(oc->path, filename,
1343                                sizeof(oc->path));
1344                        oc->path[sizeof(oc->path)-1] = '\0';
1345
1346                        free(new_filename);
1347                        return ret;
1348                } else {
1349                        if (only_to_die)
1350                                die("Invalid object name '%.*s'.", len, name);
1351                }
1352        }
1353        return ret;
1354}
1355
1356/*
1357 * Call this function when you know "name" given by the end user must
1358 * name an object but it doesn't; the function _may_ die with a better
1359 * diagnostic message than "no such object 'name'", e.g. "Path 'doc' does not
1360 * exist in 'HEAD'" when given "HEAD:doc", or it may return in which case
1361 * you have a chance to diagnose the error further.
1362 */
1363void maybe_die_on_misspelt_object_name(const char *name, const char *prefix)
1364{
1365        struct object_context oc;
1366        unsigned char sha1[20];
1367        get_sha1_with_context_1(name, GET_SHA1_ONLY_TO_DIE, prefix, sha1, &oc);
1368}
1369
1370int get_sha1_with_context(const char *str, unsigned flags, unsigned char *sha1, struct object_context *orc)
1371{
1372        return get_sha1_with_context_1(str, flags, NULL, sha1, orc);
1373}