sha1_name.con commit do not write null sha1s to on-disk index (4337b58)
   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
  12static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
  13{
  14        struct alternate_object_database *alt;
  15        char hex[40];
  16        int found = 0;
  17        static struct alternate_object_database *fakeent;
  18
  19        if (!fakeent) {
  20                const char *objdir = get_object_directory();
  21                int objdir_len = strlen(objdir);
  22                int entlen = objdir_len + 43;
  23                fakeent = xmalloc(sizeof(*fakeent) + entlen);
  24                memcpy(fakeent->base, objdir, objdir_len);
  25                fakeent->name = fakeent->base + objdir_len + 1;
  26                fakeent->name[-1] = '/';
  27        }
  28        fakeent->next = alt_odb_list;
  29
  30        sprintf(hex, "%.2s", name);
  31        for (alt = fakeent; alt && found < 2; alt = alt->next) {
  32                struct dirent *de;
  33                DIR *dir;
  34                sprintf(alt->name, "%.2s/", name);
  35                dir = opendir(alt->base);
  36                if (!dir)
  37                        continue;
  38                while ((de = readdir(dir)) != NULL) {
  39                        if (strlen(de->d_name) != 38)
  40                                continue;
  41                        if (memcmp(de->d_name, name + 2, len - 2))
  42                                continue;
  43                        if (!found) {
  44                                memcpy(hex + 2, de->d_name, 38);
  45                                found++;
  46                        }
  47                        else if (memcmp(hex + 2, de->d_name, 38)) {
  48                                found = 2;
  49                                break;
  50                        }
  51                }
  52                closedir(dir);
  53        }
  54        if (found == 1)
  55                return get_sha1_hex(hex, sha1) == 0;
  56        return found;
  57}
  58
  59static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
  60{
  61        do {
  62                if (*a != *b)
  63                        return 0;
  64                a++;
  65                b++;
  66                len -= 2;
  67        } while (len > 1);
  68        if (len)
  69                if ((*a ^ *b) & 0xf0)
  70                        return 0;
  71        return 1;
  72}
  73
  74static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
  75{
  76        struct packed_git *p;
  77        const unsigned char *found_sha1 = NULL;
  78        int found = 0;
  79
  80        prepare_packed_git();
  81        for (p = packed_git; p && found < 2; p = p->next) {
  82                uint32_t num, last;
  83                uint32_t first = 0;
  84                open_pack_index(p);
  85                num = p->num_objects;
  86                last = num;
  87                while (first < last) {
  88                        uint32_t mid = (first + last) / 2;
  89                        const unsigned char *now;
  90                        int cmp;
  91
  92                        now = nth_packed_object_sha1(p, mid);
  93                        cmp = hashcmp(match, now);
  94                        if (!cmp) {
  95                                first = mid;
  96                                break;
  97                        }
  98                        if (cmp > 0) {
  99                                first = mid+1;
 100                                continue;
 101                        }
 102                        last = mid;
 103                }
 104                if (first < num) {
 105                        const unsigned char *now, *next;
 106                       now = nth_packed_object_sha1(p, first);
 107                        if (match_sha(len, match, now)) {
 108                                next = nth_packed_object_sha1(p, first+1);
 109                               if (!next|| !match_sha(len, match, next)) {
 110                                        /* unique within this pack */
 111                                        if (!found) {
 112                                                found_sha1 = now;
 113                                                found++;
 114                                        }
 115                                        else if (hashcmp(found_sha1, now)) {
 116                                                found = 2;
 117                                                break;
 118                                        }
 119                                }
 120                                else {
 121                                        /* not even unique within this pack */
 122                                        found = 2;
 123                                        break;
 124                                }
 125                        }
 126                }
 127        }
 128        if (found == 1)
 129                hashcpy(sha1, found_sha1);
 130        return found;
 131}
 132
 133#define SHORT_NAME_NOT_FOUND (-1)
 134#define SHORT_NAME_AMBIGUOUS (-2)
 135
 136static int find_unique_short_object(int len, char *canonical,
 137                                    unsigned char *res, unsigned char *sha1)
 138{
 139        int has_unpacked, has_packed;
 140        unsigned char unpacked_sha1[20], packed_sha1[20];
 141
 142        prepare_alt_odb();
 143        has_unpacked = find_short_object_filename(len, canonical, unpacked_sha1);
 144        has_packed = find_short_packed_object(len, res, packed_sha1);
 145        if (!has_unpacked && !has_packed)
 146                return SHORT_NAME_NOT_FOUND;
 147        if (1 < has_unpacked || 1 < has_packed)
 148                return SHORT_NAME_AMBIGUOUS;
 149        if (has_unpacked != has_packed) {
 150                hashcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1));
 151                return 0;
 152        }
 153        /* Both have unique ones -- do they match? */
 154        if (hashcmp(packed_sha1, unpacked_sha1))
 155                return SHORT_NAME_AMBIGUOUS;
 156        hashcpy(sha1, packed_sha1);
 157        return 0;
 158}
 159
 160static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 161                          int quietly)
 162{
 163        int i, status;
 164        char canonical[40];
 165        unsigned char res[20];
 166
 167        if (len < MINIMUM_ABBREV || len > 40)
 168                return -1;
 169        hashclr(res);
 170        memset(canonical, 'x', 40);
 171        for (i = 0; i < len ;i++) {
 172                unsigned char c = name[i];
 173                unsigned char val;
 174                if (c >= '0' && c <= '9')
 175                        val = c - '0';
 176                else if (c >= 'a' && c <= 'f')
 177                        val = c - 'a' + 10;
 178                else if (c >= 'A' && c <='F') {
 179                        val = c - 'A' + 10;
 180                        c -= 'A' - 'a';
 181                }
 182                else
 183                        return -1;
 184                canonical[i] = c;
 185                if (!(i & 1))
 186                        val <<= 4;
 187                res[i >> 1] |= val;
 188        }
 189
 190        status = find_unique_short_object(i, canonical, res, sha1);
 191        if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
 192                return error("short SHA1 %.*s is ambiguous.", len, canonical);
 193        return status;
 194}
 195
 196const char *find_unique_abbrev(const unsigned char *sha1, int len)
 197{
 198        int status, exists;
 199        static char hex[41];
 200
 201        exists = has_sha1_file(sha1);
 202        memcpy(hex, sha1_to_hex(sha1), 40);
 203        if (len == 40 || !len)
 204                return hex;
 205        while (len < 40) {
 206                unsigned char sha1_ret[20];
 207                status = get_short_sha1(hex, len, sha1_ret, 1);
 208                if (exists
 209                    ? !status
 210                    : status == SHORT_NAME_NOT_FOUND) {
 211                        hex[len] = 0;
 212                        return hex;
 213                }
 214                len++;
 215        }
 216        return hex;
 217}
 218
 219static int ambiguous_path(const char *path, int len)
 220{
 221        int slash = 1;
 222        int cnt;
 223
 224        for (cnt = 0; cnt < len; cnt++) {
 225                switch (*path++) {
 226                case '\0':
 227                        break;
 228                case '/':
 229                        if (slash)
 230                                break;
 231                        slash = 1;
 232                        continue;
 233                case '.':
 234                        continue;
 235                default:
 236                        slash = 0;
 237                        continue;
 238                }
 239                break;
 240        }
 241        return slash;
 242}
 243
 244static inline int upstream_mark(const char *string, int len)
 245{
 246        const char *suffix[] = { "@{upstream}", "@{u}" };
 247        int i;
 248
 249        for (i = 0; i < ARRAY_SIZE(suffix); i++) {
 250                int suffix_len = strlen(suffix[i]);
 251                if (suffix_len <= len
 252                    && !memcmp(string, suffix[i], suffix_len))
 253                        return suffix_len;
 254        }
 255        return 0;
 256}
 257
 258static int get_sha1_1(const char *name, int len, unsigned char *sha1);
 259
 260static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 261{
 262        static const char *warn_msg = "refname '%.*s' is ambiguous.";
 263        char *real_ref = NULL;
 264        int refs_found = 0;
 265        int at, reflog_len;
 266
 267        if (len == 40 && !get_sha1_hex(str, sha1))
 268                return 0;
 269
 270        /* basic@{time or number or -number} format to query ref-log */
 271        reflog_len = at = 0;
 272        if (len && str[len-1] == '}') {
 273                for (at = len-2; at >= 0; at--) {
 274                        if (str[at] == '@' && str[at+1] == '{') {
 275                                if (!upstream_mark(str + at, len - at)) {
 276                                        reflog_len = (len-1) - (at+2);
 277                                        len = at;
 278                                }
 279                                break;
 280                        }
 281                }
 282        }
 283
 284        /* Accept only unambiguous ref paths. */
 285        if (len && ambiguous_path(str, len))
 286                return -1;
 287
 288        if (!len && reflog_len) {
 289                struct strbuf buf = STRBUF_INIT;
 290                int ret;
 291                /* try the @{-N} syntax for n-th checkout */
 292                ret = interpret_branch_name(str+at, &buf);
 293                if (ret > 0) {
 294                        /* substitute this branch name and restart */
 295                        return get_sha1_1(buf.buf, buf.len, sha1);
 296                } else if (ret == 0) {
 297                        return -1;
 298                }
 299                /* allow "@{...}" to mean the current branch reflog */
 300                refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
 301        } else if (reflog_len)
 302                refs_found = dwim_log(str, len, sha1, &real_ref);
 303        else
 304                refs_found = dwim_ref(str, len, sha1, &real_ref);
 305
 306        if (!refs_found)
 307                return -1;
 308
 309        if (warn_ambiguous_refs && refs_found > 1)
 310                warning(warn_msg, len, str);
 311
 312        if (reflog_len) {
 313                int nth, i;
 314                unsigned long at_time;
 315                unsigned long co_time;
 316                int co_tz, co_cnt;
 317
 318                /* a @{-N} placed anywhere except the start is an error */
 319                if (str[at+2] == '-')
 320                        return -1;
 321
 322                /* Is it asking for N-th entry, or approxidate? */
 323                for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 324                        char ch = str[at+2+i];
 325                        if ('0' <= ch && ch <= '9')
 326                                nth = nth * 10 + ch - '0';
 327                        else
 328                                nth = -1;
 329                }
 330                if (100000000 <= nth) {
 331                        at_time = nth;
 332                        nth = -1;
 333                } else if (0 <= nth)
 334                        at_time = 0;
 335                else {
 336                        int errors = 0;
 337                        char *tmp = xstrndup(str + at + 2, reflog_len);
 338                        at_time = approxidate_careful(tmp, &errors);
 339                        free(tmp);
 340                        if (errors)
 341                                return -1;
 342                }
 343                if (read_ref_at(real_ref, at_time, nth, sha1, NULL,
 344                                &co_time, &co_tz, &co_cnt)) {
 345                        if (at_time)
 346                                warning("Log for '%.*s' only goes "
 347                                        "back to %s.", len, str,
 348                                        show_date(co_time, co_tz, DATE_RFC2822));
 349                        else {
 350                                free(real_ref);
 351                                die("Log for '%.*s' only has %d entries.",
 352                                    len, str, co_cnt);
 353                        }
 354                }
 355        }
 356
 357        free(real_ref);
 358        return 0;
 359}
 360
 361static int get_parent(const char *name, int len,
 362                      unsigned char *result, int idx)
 363{
 364        unsigned char sha1[20];
 365        int ret = get_sha1_1(name, len, sha1);
 366        struct commit *commit;
 367        struct commit_list *p;
 368
 369        if (ret)
 370                return ret;
 371        commit = lookup_commit_reference(sha1);
 372        if (!commit)
 373                return -1;
 374        if (parse_commit(commit))
 375                return -1;
 376        if (!idx) {
 377                hashcpy(result, commit->object.sha1);
 378                return 0;
 379        }
 380        p = commit->parents;
 381        while (p) {
 382                if (!--idx) {
 383                        hashcpy(result, p->item->object.sha1);
 384                        return 0;
 385                }
 386                p = p->next;
 387        }
 388        return -1;
 389}
 390
 391static int get_nth_ancestor(const char *name, int len,
 392                            unsigned char *result, int generation)
 393{
 394        unsigned char sha1[20];
 395        struct commit *commit;
 396        int ret;
 397
 398        ret = get_sha1_1(name, len, sha1);
 399        if (ret)
 400                return ret;
 401        commit = lookup_commit_reference(sha1);
 402        if (!commit)
 403                return -1;
 404
 405        while (generation--) {
 406                if (parse_commit(commit) || !commit->parents)
 407                        return -1;
 408                commit = commit->parents->item;
 409        }
 410        hashcpy(result, commit->object.sha1);
 411        return 0;
 412}
 413
 414struct object *peel_to_type(const char *name, int namelen,
 415                            struct object *o, enum object_type expected_type)
 416{
 417        if (name && !namelen)
 418                namelen = strlen(name);
 419        while (1) {
 420                if (!o || (!o->parsed && !parse_object(o->sha1)))
 421                        return NULL;
 422                if (o->type == expected_type)
 423                        return o;
 424                if (o->type == OBJ_TAG)
 425                        o = ((struct tag*) o)->tagged;
 426                else if (o->type == OBJ_COMMIT)
 427                        o = &(((struct commit *) o)->tree->object);
 428                else {
 429                        if (name)
 430                                error("%.*s: expected %s type, but the object "
 431                                      "dereferences to %s type",
 432                                      namelen, name, typename(expected_type),
 433                                      typename(o->type));
 434                        return NULL;
 435                }
 436        }
 437}
 438
 439static int peel_onion(const char *name, int len, unsigned char *sha1)
 440{
 441        unsigned char outer[20];
 442        const char *sp;
 443        unsigned int expected_type = 0;
 444        struct object *o;
 445
 446        /*
 447         * "ref^{type}" dereferences ref repeatedly until you cannot
 448         * dereference anymore, or you get an object of given type,
 449         * whichever comes first.  "ref^{}" means just dereference
 450         * tags until you get a non-tag.  "ref^0" is a shorthand for
 451         * "ref^{commit}".  "commit^{tree}" could be used to find the
 452         * top-level tree of the given commit.
 453         */
 454        if (len < 4 || name[len-1] != '}')
 455                return -1;
 456
 457        for (sp = name + len - 1; name <= sp; sp--) {
 458                int ch = *sp;
 459                if (ch == '{' && name < sp && sp[-1] == '^')
 460                        break;
 461        }
 462        if (sp <= name)
 463                return -1;
 464
 465        sp++; /* beginning of type name, or closing brace for empty */
 466        if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
 467                expected_type = OBJ_COMMIT;
 468        else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
 469                expected_type = OBJ_TREE;
 470        else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
 471                expected_type = OBJ_BLOB;
 472        else if (sp[0] == '}')
 473                expected_type = OBJ_NONE;
 474        else if (sp[0] == '/')
 475                expected_type = OBJ_COMMIT;
 476        else
 477                return -1;
 478
 479        if (get_sha1_1(name, sp - name - 2, outer))
 480                return -1;
 481
 482        o = parse_object(outer);
 483        if (!o)
 484                return -1;
 485        if (!expected_type) {
 486                o = deref_tag(o, name, sp - name - 2);
 487                if (!o || (!o->parsed && !parse_object(o->sha1)))
 488                        return -1;
 489                hashcpy(sha1, o->sha1);
 490                return 0;
 491        }
 492
 493        /*
 494         * At this point, the syntax look correct, so
 495         * if we do not get the needed object, we should
 496         * barf.
 497         */
 498        o = peel_to_type(name, len, o, expected_type);
 499        if (!o)
 500                return -1;
 501
 502        hashcpy(sha1, o->sha1);
 503        if (sp[0] == '/') {
 504                /* "$commit^{/foo}" */
 505                char *prefix;
 506                int ret;
 507                struct commit_list *list = NULL;
 508
 509                /*
 510                 * $commit^{/}. Some regex implementation may reject.
 511                 * We don't need regex anyway. '' pattern always matches.
 512                 */
 513                if (sp[1] == '}')
 514                        return 0;
 515
 516                prefix = xstrndup(sp + 1, name + len - 1 - (sp + 1));
 517                commit_list_insert((struct commit *)o, &list);
 518                ret = get_sha1_oneline(prefix, sha1, list);
 519                free(prefix);
 520                return ret;
 521        }
 522        return 0;
 523}
 524
 525static int get_describe_name(const char *name, int len, unsigned char *sha1)
 526{
 527        const char *cp;
 528
 529        for (cp = name + len - 1; name + 2 <= cp; cp--) {
 530                char ch = *cp;
 531                if (hexval(ch) & ~0377) {
 532                        /* We must be looking at g in "SOMETHING-g"
 533                         * for it to be describe output.
 534                         */
 535                        if (ch == 'g' && cp[-1] == '-') {
 536                                cp++;
 537                                len -= cp - name;
 538                                return get_short_sha1(cp, len, sha1, 1);
 539                        }
 540                }
 541        }
 542        return -1;
 543}
 544
 545static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 546{
 547        int ret, has_suffix;
 548        const char *cp;
 549
 550        /*
 551         * "name~3" is "name^^^", "name~" is "name~1", and "name^" is "name^1".
 552         */
 553        has_suffix = 0;
 554        for (cp = name + len - 1; name <= cp; cp--) {
 555                int ch = *cp;
 556                if ('0' <= ch && ch <= '9')
 557                        continue;
 558                if (ch == '~' || ch == '^')
 559                        has_suffix = ch;
 560                break;
 561        }
 562
 563        if (has_suffix) {
 564                int num = 0;
 565                int len1 = cp - name;
 566                cp++;
 567                while (cp < name + len)
 568                        num = num * 10 + *cp++ - '0';
 569                if (!num && len1 == len - 1)
 570                        num = 1;
 571                if (has_suffix == '^')
 572                        return get_parent(name, len1, sha1, num);
 573                /* else if (has_suffix == '~') -- goes without saying */
 574                return get_nth_ancestor(name, len1, sha1, num);
 575        }
 576
 577        ret = peel_onion(name, len, sha1);
 578        if (!ret)
 579                return 0;
 580
 581        ret = get_sha1_basic(name, len, sha1);
 582        if (!ret)
 583                return 0;
 584
 585        /* It could be describe output that is "SOMETHING-gXXXX" */
 586        ret = get_describe_name(name, len, sha1);
 587        if (!ret)
 588                return 0;
 589
 590        return get_short_sha1(name, len, sha1, 0);
 591}
 592
 593/*
 594 * This interprets names like ':/Initial revision of "git"' by searching
 595 * through history and returning the first commit whose message starts
 596 * the given regular expression.
 597 *
 598 * For future extension, ':/!' is reserved. If you want to match a message
 599 * beginning with a '!', you have to repeat the exclamation mark.
 600 */
 601#define ONELINE_SEEN (1u<<20)
 602
 603static int handle_one_ref(const char *path,
 604                const unsigned char *sha1, int flag, void *cb_data)
 605{
 606        struct commit_list **list = cb_data;
 607        struct object *object = parse_object(sha1);
 608        if (!object)
 609                return 0;
 610        if (object->type == OBJ_TAG) {
 611                object = deref_tag(object, path, strlen(path));
 612                if (!object)
 613                        return 0;
 614        }
 615        if (object->type != OBJ_COMMIT)
 616                return 0;
 617        commit_list_insert_by_date((struct commit *)object, list);
 618        return 0;
 619}
 620
 621static int get_sha1_oneline(const char *prefix, unsigned char *sha1,
 622                            struct commit_list *list)
 623{
 624        struct commit_list *backup = NULL, *l;
 625        int found = 0;
 626        regex_t regex;
 627
 628        if (prefix[0] == '!') {
 629                if (prefix[1] != '!')
 630                        die ("Invalid search pattern: %s", prefix);
 631                prefix++;
 632        }
 633
 634        if (regcomp(&regex, prefix, REG_EXTENDED))
 635                die("Invalid search pattern: %s", prefix);
 636
 637        for (l = list; l; l = l->next) {
 638                l->item->object.flags |= ONELINE_SEEN;
 639                commit_list_insert(l->item, &backup);
 640        }
 641        while (list) {
 642                char *p, *to_free = NULL;
 643                struct commit *commit;
 644                enum object_type type;
 645                unsigned long size;
 646                int matches;
 647
 648                commit = pop_most_recent_commit(&list, ONELINE_SEEN);
 649                if (!parse_object(commit->object.sha1))
 650                        continue;
 651                if (commit->buffer)
 652                        p = commit->buffer;
 653                else {
 654                        p = read_sha1_file(commit->object.sha1, &type, &size);
 655                        if (!p)
 656                                continue;
 657                        to_free = p;
 658                }
 659
 660                p = strstr(p, "\n\n");
 661                matches = p && !regexec(&regex, p + 2, 0, NULL, 0);
 662                free(to_free);
 663
 664                if (matches) {
 665                        hashcpy(sha1, commit->object.sha1);
 666                        found = 1;
 667                        break;
 668                }
 669        }
 670        regfree(&regex);
 671        free_commit_list(list);
 672        for (l = backup; l; l = l->next)
 673                clear_commit_marks(l->item, ONELINE_SEEN);
 674        free_commit_list(backup);
 675        return found ? 0 : -1;
 676}
 677
 678struct grab_nth_branch_switch_cbdata {
 679        long cnt, alloc;
 680        struct strbuf *buf;
 681};
 682
 683static int grab_nth_branch_switch(unsigned char *osha1, unsigned char *nsha1,
 684                                  const char *email, unsigned long timestamp, int tz,
 685                                  const char *message, void *cb_data)
 686{
 687        struct grab_nth_branch_switch_cbdata *cb = cb_data;
 688        const char *match = NULL, *target = NULL;
 689        size_t len;
 690        int nth;
 691
 692        if (!prefixcmp(message, "checkout: moving from ")) {
 693                match = message + strlen("checkout: moving from ");
 694                target = strstr(match, " to ");
 695        }
 696
 697        if (!match || !target)
 698                return 0;
 699
 700        len = target - match;
 701        nth = cb->cnt++ % cb->alloc;
 702        strbuf_reset(&cb->buf[nth]);
 703        strbuf_add(&cb->buf[nth], match, len);
 704        return 0;
 705}
 706
 707/*
 708 * Parse @{-N} syntax, return the number of characters parsed
 709 * if successful; otherwise signal an error with negative value.
 710 */
 711static int interpret_nth_prior_checkout(const char *name, struct strbuf *buf)
 712{
 713        long nth;
 714        int i, retval;
 715        struct grab_nth_branch_switch_cbdata cb;
 716        const char *brace;
 717        char *num_end;
 718
 719        if (name[0] != '@' || name[1] != '{' || name[2] != '-')
 720                return -1;
 721        brace = strchr(name, '}');
 722        if (!brace)
 723                return -1;
 724        nth = strtol(name+3, &num_end, 10);
 725        if (num_end != brace)
 726                return -1;
 727        if (nth <= 0)
 728                return -1;
 729        cb.alloc = nth;
 730        cb.buf = xmalloc(nth * sizeof(struct strbuf));
 731        for (i = 0; i < nth; i++)
 732                strbuf_init(&cb.buf[i], 20);
 733        cb.cnt = 0;
 734        retval = 0;
 735        for_each_recent_reflog_ent("HEAD", grab_nth_branch_switch, 40960, &cb);
 736        if (cb.cnt < nth) {
 737                cb.cnt = 0;
 738                for_each_reflog_ent("HEAD", grab_nth_branch_switch, &cb);
 739        }
 740        if (cb.cnt < nth)
 741                goto release_return;
 742        i = cb.cnt % nth;
 743        strbuf_reset(buf);
 744        strbuf_add(buf, cb.buf[i].buf, cb.buf[i].len);
 745        retval = brace-name+1;
 746
 747release_return:
 748        for (i = 0; i < nth; i++)
 749                strbuf_release(&cb.buf[i]);
 750        free(cb.buf);
 751
 752        return retval;
 753}
 754
 755int get_sha1_mb(const char *name, unsigned char *sha1)
 756{
 757        struct commit *one, *two;
 758        struct commit_list *mbs;
 759        unsigned char sha1_tmp[20];
 760        const char *dots;
 761        int st;
 762
 763        dots = strstr(name, "...");
 764        if (!dots)
 765                return get_sha1(name, sha1);
 766        if (dots == name)
 767                st = get_sha1("HEAD", sha1_tmp);
 768        else {
 769                struct strbuf sb;
 770                strbuf_init(&sb, dots - name);
 771                strbuf_add(&sb, name, dots - name);
 772                st = get_sha1(sb.buf, sha1_tmp);
 773                strbuf_release(&sb);
 774        }
 775        if (st)
 776                return st;
 777        one = lookup_commit_reference_gently(sha1_tmp, 0);
 778        if (!one)
 779                return -1;
 780
 781        if (get_sha1(dots[3] ? (dots + 3) : "HEAD", sha1_tmp))
 782                return -1;
 783        two = lookup_commit_reference_gently(sha1_tmp, 0);
 784        if (!two)
 785                return -1;
 786        mbs = get_merge_bases(one, two, 1);
 787        if (!mbs || mbs->next)
 788                st = -1;
 789        else {
 790                st = 0;
 791                hashcpy(sha1, mbs->item->object.sha1);
 792        }
 793        free_commit_list(mbs);
 794        return st;
 795}
 796
 797/*
 798 * This reads short-hand syntax that not only evaluates to a commit
 799 * object name, but also can act as if the end user spelled the name
 800 * of the branch from the command line.
 801 *
 802 * - "@{-N}" finds the name of the Nth previous branch we were on, and
 803 *   places the name of the branch in the given buf and returns the
 804 *   number of characters parsed if successful.
 805 *
 806 * - "<branch>@{upstream}" finds the name of the other ref that
 807 *   <branch> is configured to merge with (missing <branch> defaults
 808 *   to the current branch), and places the name of the branch in the
 809 *   given buf and returns the number of characters parsed if
 810 *   successful.
 811 *
 812 * If the input is not of the accepted format, it returns a negative
 813 * number to signal an error.
 814 *
 815 * If the input was ok but there are not N branch switches in the
 816 * reflog, it returns 0.
 817 */
 818int interpret_branch_name(const char *name, struct strbuf *buf)
 819{
 820        char *cp;
 821        struct branch *upstream;
 822        int namelen = strlen(name);
 823        int len = interpret_nth_prior_checkout(name, buf);
 824        int tmp_len;
 825
 826        if (!len)
 827                return len; /* syntax Ok, not enough switches */
 828        if (0 < len && len == namelen)
 829                return len; /* consumed all */
 830        else if (0 < len) {
 831                /* we have extra data, which might need further processing */
 832                struct strbuf tmp = STRBUF_INIT;
 833                int used = buf->len;
 834                int ret;
 835
 836                strbuf_add(buf, name + len, namelen - len);
 837                ret = interpret_branch_name(buf->buf, &tmp);
 838                /* that data was not interpreted, remove our cruft */
 839                if (ret < 0) {
 840                        strbuf_setlen(buf, used);
 841                        return len;
 842                }
 843                strbuf_reset(buf);
 844                strbuf_addbuf(buf, &tmp);
 845                strbuf_release(&tmp);
 846                /* tweak for size of {-N} versus expanded ref name */
 847                return ret - used + len;
 848        }
 849
 850        cp = strchr(name, '@');
 851        if (!cp)
 852                return -1;
 853        tmp_len = upstream_mark(cp, namelen - (cp - name));
 854        if (!tmp_len)
 855                return -1;
 856        len = cp + tmp_len - name;
 857        cp = xstrndup(name, cp - name);
 858        upstream = branch_get(*cp ? cp : NULL);
 859        if (!upstream
 860            || !upstream->merge
 861            || !upstream->merge[0]->dst)
 862                return error("No upstream branch found for '%s'", cp);
 863        free(cp);
 864        cp = shorten_unambiguous_ref(upstream->merge[0]->dst, 0);
 865        strbuf_reset(buf);
 866        strbuf_addstr(buf, cp);
 867        free(cp);
 868        return len;
 869}
 870
 871int strbuf_branchname(struct strbuf *sb, const char *name)
 872{
 873        int len = strlen(name);
 874        if (interpret_branch_name(name, sb) == len)
 875                return 0;
 876        strbuf_add(sb, name, len);
 877        return len;
 878}
 879
 880int strbuf_check_branch_ref(struct strbuf *sb, const char *name)
 881{
 882        strbuf_branchname(sb, name);
 883        if (name[0] == '-')
 884                return -1;
 885        strbuf_splice(sb, 0, 0, "refs/heads/", 11);
 886        return check_refname_format(sb->buf, 0);
 887}
 888
 889/*
 890 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
 891 * notably "xyz^" for "parent of xyz"
 892 */
 893int get_sha1(const char *name, unsigned char *sha1)
 894{
 895        struct object_context unused;
 896        return get_sha1_with_context(name, sha1, &unused);
 897}
 898
 899/* Must be called only when object_name:filename doesn't exist. */
 900static void diagnose_invalid_sha1_path(const char *prefix,
 901                                       const char *filename,
 902                                       const unsigned char *tree_sha1,
 903                                       const char *object_name)
 904{
 905        struct stat st;
 906        unsigned char sha1[20];
 907        unsigned mode;
 908
 909        if (!prefix)
 910                prefix = "";
 911
 912        if (!lstat(filename, &st))
 913                die("Path '%s' exists on disk, but not in '%s'.",
 914                    filename, object_name);
 915        if (errno == ENOENT || errno == ENOTDIR) {
 916                char *fullname = xmalloc(strlen(filename)
 917                                             + strlen(prefix) + 1);
 918                strcpy(fullname, prefix);
 919                strcat(fullname, filename);
 920
 921                if (!get_tree_entry(tree_sha1, fullname,
 922                                    sha1, &mode)) {
 923                        die("Path '%s' exists, but not '%s'.\n"
 924                            "Did you mean '%s:%s' aka '%s:./%s'?",
 925                            fullname,
 926                            filename,
 927                            object_name,
 928                            fullname,
 929                            object_name,
 930                            filename);
 931                }
 932                die("Path '%s' does not exist in '%s'",
 933                    filename, object_name);
 934        }
 935}
 936
 937/* Must be called only when :stage:filename doesn't exist. */
 938static void diagnose_invalid_index_path(int stage,
 939                                        const char *prefix,
 940                                        const char *filename)
 941{
 942        struct stat st;
 943        struct cache_entry *ce;
 944        int pos;
 945        unsigned namelen = strlen(filename);
 946        unsigned fullnamelen;
 947        char *fullname;
 948
 949        if (!prefix)
 950                prefix = "";
 951
 952        /* Wrong stage number? */
 953        pos = cache_name_pos(filename, namelen);
 954        if (pos < 0)
 955                pos = -pos - 1;
 956        if (pos < active_nr) {
 957                ce = active_cache[pos];
 958                if (ce_namelen(ce) == namelen &&
 959                    !memcmp(ce->name, filename, namelen))
 960                        die("Path '%s' is in the index, but not at stage %d.\n"
 961                            "Did you mean ':%d:%s'?",
 962                            filename, stage,
 963                            ce_stage(ce), filename);
 964        }
 965
 966        /* Confusion between relative and absolute filenames? */
 967        fullnamelen = namelen + strlen(prefix);
 968        fullname = xmalloc(fullnamelen + 1);
 969        strcpy(fullname, prefix);
 970        strcat(fullname, filename);
 971        pos = cache_name_pos(fullname, fullnamelen);
 972        if (pos < 0)
 973                pos = -pos - 1;
 974        if (pos < active_nr) {
 975                ce = active_cache[pos];
 976                if (ce_namelen(ce) == fullnamelen &&
 977                    !memcmp(ce->name, fullname, fullnamelen))
 978                        die("Path '%s' is in the index, but not '%s'.\n"
 979                            "Did you mean ':%d:%s' aka ':%d:./%s'?",
 980                            fullname, filename,
 981                            ce_stage(ce), fullname,
 982                            ce_stage(ce), filename);
 983        }
 984
 985        if (!lstat(filename, &st))
 986                die("Path '%s' exists on disk, but not in the index.", filename);
 987        if (errno == ENOENT || errno == ENOTDIR)
 988                die("Path '%s' does not exist (neither on disk nor in the index).",
 989                    filename);
 990
 991        free(fullname);
 992}
 993
 994
 995int get_sha1_with_mode_1(const char *name, unsigned char *sha1, unsigned *mode,
 996                         int only_to_die, const char *prefix)
 997{
 998        struct object_context oc;
 999        int ret;
1000        ret = get_sha1_with_context_1(name, sha1, &oc, only_to_die, prefix);
1001        *mode = oc.mode;
1002        return ret;
1003}
1004
1005static char *resolve_relative_path(const char *rel)
1006{
1007        if (prefixcmp(rel, "./") && prefixcmp(rel, "../"))
1008                return NULL;
1009
1010        if (!startup_info)
1011                die("BUG: startup_info struct is not initialized.");
1012
1013        if (!is_inside_work_tree())
1014                die("relative path syntax can't be used outside working tree.");
1015
1016        /* die() inside prefix_path() if resolved path is outside worktree */
1017        return prefix_path(startup_info->prefix,
1018                           startup_info->prefix ? strlen(startup_info->prefix) : 0,
1019                           rel);
1020}
1021
1022int get_sha1_with_context_1(const char *name, unsigned char *sha1,
1023                            struct object_context *oc,
1024                            int only_to_die, const char *prefix)
1025{
1026        int ret, bracket_depth;
1027        int namelen = strlen(name);
1028        const char *cp;
1029
1030        memset(oc, 0, sizeof(*oc));
1031        oc->mode = S_IFINVALID;
1032        ret = get_sha1_1(name, namelen, sha1);
1033        if (!ret)
1034                return ret;
1035        /* sha1:path --> object name of path in ent sha1
1036         * :path -> object name of absolute path in index
1037         * :./path -> object name of path relative to cwd in index
1038         * :[0-3]:path -> object name of path in index at stage
1039         * :/foo -> recent commit matching foo
1040         */
1041        if (name[0] == ':') {
1042                int stage = 0;
1043                struct cache_entry *ce;
1044                char *new_path = NULL;
1045                int pos;
1046                if (!only_to_die && namelen > 2 && name[1] == '/') {
1047                        struct commit_list *list = NULL;
1048                        for_each_ref(handle_one_ref, &list);
1049                        return get_sha1_oneline(name + 2, sha1, list);
1050                }
1051                if (namelen < 3 ||
1052                    name[2] != ':' ||
1053                    name[1] < '0' || '3' < name[1])
1054                        cp = name + 1;
1055                else {
1056                        stage = name[1] - '0';
1057                        cp = name + 3;
1058                }
1059                new_path = resolve_relative_path(cp);
1060                if (!new_path) {
1061                        namelen = namelen - (cp - name);
1062                } else {
1063                        cp = new_path;
1064                        namelen = strlen(cp);
1065                }
1066
1067                strncpy(oc->path, cp,
1068                        sizeof(oc->path));
1069                oc->path[sizeof(oc->path)-1] = '\0';
1070
1071                if (!active_cache)
1072                        read_cache();
1073                pos = cache_name_pos(cp, namelen);
1074                if (pos < 0)
1075                        pos = -pos - 1;
1076                while (pos < active_nr) {
1077                        ce = active_cache[pos];
1078                        if (ce_namelen(ce) != namelen ||
1079                            memcmp(ce->name, cp, namelen))
1080                                break;
1081                        if (ce_stage(ce) == stage) {
1082                                hashcpy(sha1, ce->sha1);
1083                                oc->mode = ce->ce_mode;
1084                                free(new_path);
1085                                return 0;
1086                        }
1087                        pos++;
1088                }
1089                if (only_to_die && name[1] && name[1] != '/')
1090                        diagnose_invalid_index_path(stage, prefix, cp);
1091                free(new_path);
1092                return -1;
1093        }
1094        for (cp = name, bracket_depth = 0; *cp; cp++) {
1095                if (*cp == '{')
1096                        bracket_depth++;
1097                else if (bracket_depth && *cp == '}')
1098                        bracket_depth--;
1099                else if (!bracket_depth && *cp == ':')
1100                        break;
1101        }
1102        if (*cp == ':') {
1103                unsigned char tree_sha1[20];
1104                char *object_name = NULL;
1105                if (only_to_die) {
1106                        object_name = xmalloc(cp-name+1);
1107                        strncpy(object_name, name, cp-name);
1108                        object_name[cp-name] = '\0';
1109                }
1110                if (!get_sha1_1(name, cp-name, tree_sha1)) {
1111                        const char *filename = cp+1;
1112                        char *new_filename = NULL;
1113
1114                        new_filename = resolve_relative_path(filename);
1115                        if (new_filename)
1116                                filename = new_filename;
1117                        ret = get_tree_entry(tree_sha1, filename, sha1, &oc->mode);
1118                        if (only_to_die) {
1119                                diagnose_invalid_sha1_path(prefix, filename,
1120                                                           tree_sha1, object_name);
1121                                free(object_name);
1122                        }
1123                        hashcpy(oc->tree, tree_sha1);
1124                        strncpy(oc->path, filename,
1125                                sizeof(oc->path));
1126                        oc->path[sizeof(oc->path)-1] = '\0';
1127
1128                        free(new_filename);
1129                        return ret;
1130                } else {
1131                        if (only_to_die)
1132                                die("Invalid object name '%s'.", object_name);
1133                }
1134        }
1135        return ret;
1136}