Andrew's git / gitweb.git / sha1_name.c
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sha1_name.con commit add replay and log to the usage string of git-bisect (4ef40cd)
   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
   9static int find_short_object_filename(int len, const char *name, unsigned char *sha1)
  10{
  11        struct alternate_object_database *alt;
  12        char hex[40];
  13        int found = 0;
  14        static struct alternate_object_database *fakeent;
  15
  16        if (!fakeent) {
  17                const char *objdir = get_object_directory();
  18                int objdir_len = strlen(objdir);
  19                int entlen = objdir_len + 43;
  20                fakeent = xmalloc(sizeof(*fakeent) + entlen);
  21                memcpy(fakeent->base, objdir, objdir_len);
  22                fakeent->name = fakeent->base + objdir_len + 1;
  23                fakeent->name[-1] = '/';
  24        }
  25        fakeent->next = alt_odb_list;
  26
  27        sprintf(hex, "%.2s", name);
  28        for (alt = fakeent; alt && found < 2; alt = alt->next) {
  29                struct dirent *de;
  30                DIR *dir;
  31                sprintf(alt->name, "%.2s/", name);
  32                dir = opendir(alt->base);
  33                if (!dir)
  34                        continue;
  35                while ((de = readdir(dir)) != NULL) {
  36                        if (strlen(de->d_name) != 38)
  37                                continue;
  38                        if (memcmp(de->d_name, name + 2, len - 2))
  39                                continue;
  40                        if (!found) {
  41                                memcpy(hex + 2, de->d_name, 38);
  42                                found++;
  43                        }
  44                        else if (memcmp(hex + 2, de->d_name, 38)) {
  45                                found = 2;
  46                                break;
  47                        }
  48                }
  49                closedir(dir);
  50        }
  51        if (found == 1)
  52                return get_sha1_hex(hex, sha1) == 0;
  53        return found;
  54}
  55
  56static int match_sha(unsigned len, const unsigned char *a, const unsigned char *b)
  57{
  58        do {
  59                if (*a != *b)
  60                        return 0;
  61                a++;
  62                b++;
  63                len -= 2;
  64        } while (len > 1);
  65        if (len)
  66                if ((*a ^ *b) & 0xf0)
  67                        return 0;
  68        return 1;
  69}
  70
  71static int find_short_packed_object(int len, const unsigned char *match, unsigned char *sha1)
  72{
  73        struct packed_git *p;
  74        unsigned char found_sha1[20];
  75        int found = 0;
  76
  77        prepare_packed_git();
  78        for (p = packed_git; p && found < 2; p = p->next) {
  79                unsigned num = num_packed_objects(p);
  80                unsigned first = 0, last = num;
  81                while (first < last) {
  82                        unsigned mid = (first + last) / 2;
  83                        unsigned char now[20];
  84                        int cmp;
  85
  86                        nth_packed_object_sha1(p, mid, now);
  87                        cmp = hashcmp(match, now);
  88                        if (!cmp) {
  89                                first = mid;
  90                                break;
  91                        }
  92                        if (cmp > 0) {
  93                                first = mid+1;
  94                                continue;
  95                        }
  96                        last = mid;
  97                }
  98                if (first < num) {
  99                        unsigned char now[20], next[20];
 100                        nth_packed_object_sha1(p, first, now);
 101                        if (match_sha(len, match, now)) {
 102                                if (nth_packed_object_sha1(p, first+1, next) ||
 103                                    !match_sha(len, match, next)) {
 104                                        /* unique within this pack */
 105                                        if (!found) {
 106                                                hashcpy(found_sha1, now);
 107                                                found++;
 108                                        }
 109                                        else if (hashcmp(found_sha1, now)) {
 110                                                found = 2;
 111                                                break;
 112                                        }
 113                                }
 114                                else {
 115                                        /* not even unique within this pack */
 116                                        found = 2;
 117                                        break;
 118                                }
 119                        }
 120                }
 121        }
 122        if (found == 1)
 123                hashcpy(sha1, found_sha1);
 124        return found;
 125}
 126
 127#define SHORT_NAME_NOT_FOUND (-1)
 128#define SHORT_NAME_AMBIGUOUS (-2)
 129
 130static int find_unique_short_object(int len, char *canonical,
 131                                    unsigned char *res, unsigned char *sha1)
 132{
 133        int has_unpacked, has_packed;
 134        unsigned char unpacked_sha1[20], packed_sha1[20];
 135
 136        has_unpacked = find_short_object_filename(len, canonical, unpacked_sha1);
 137        has_packed = find_short_packed_object(len, res, packed_sha1);
 138        if (!has_unpacked && !has_packed)
 139                return SHORT_NAME_NOT_FOUND;
 140        if (1 < has_unpacked || 1 < has_packed)
 141                return SHORT_NAME_AMBIGUOUS;
 142        if (has_unpacked != has_packed) {
 143                hashcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1));
 144                return 0;
 145        }
 146        /* Both have unique ones -- do they match? */
 147        if (hashcmp(packed_sha1, unpacked_sha1))
 148                return SHORT_NAME_AMBIGUOUS;
 149        hashcpy(sha1, packed_sha1);
 150        return 0;
 151}
 152
 153static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 154                          int quietly)
 155{
 156        int i, status;
 157        char canonical[40];
 158        unsigned char res[20];
 159
 160        if (len < MINIMUM_ABBREV || len > 40)
 161                return -1;
 162        hashclr(res);
 163        memset(canonical, 'x', 40);
 164        for (i = 0; i < len ;i++) {
 165                unsigned char c = name[i];
 166                unsigned char val;
 167                if (c >= '0' && c <= '9')
 168                        val = c - '0';
 169                else if (c >= 'a' && c <= 'f')
 170                        val = c - 'a' + 10;
 171                else if (c >= 'A' && c <='F') {
 172                        val = c - 'A' + 10;
 173                        c -= 'A' - 'a';
 174                }
 175                else
 176                        return -1;
 177                canonical[i] = c;
 178                if (!(i & 1))
 179                        val <<= 4;
 180                res[i >> 1] |= val;
 181        }
 182
 183        status = find_unique_short_object(i, canonical, res, sha1);
 184        if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
 185                return error("short SHA1 %.*s is ambiguous.", len, canonical);
 186        return status;
 187}
 188
 189const char *find_unique_abbrev(const unsigned char *sha1, int len)
 190{
 191        int status, is_null;
 192        static char hex[41];
 193
 194        is_null = is_null_sha1(sha1);
 195        memcpy(hex, sha1_to_hex(sha1), 40);
 196        if (len == 40 || !len)
 197                return hex;
 198        while (len < 40) {
 199                unsigned char sha1_ret[20];
 200                status = get_short_sha1(hex, len, sha1_ret, 1);
 201                if (!status ||
 202                    (is_null && status != SHORT_NAME_AMBIGUOUS)) {
 203                        hex[len] = 0;
 204                        return hex;
 205                }
 206                if (status != SHORT_NAME_AMBIGUOUS)
 207                        return NULL;
 208                len++;
 209        }
 210        return NULL;
 211}
 212
 213static int ambiguous_path(const char *path, int len)
 214{
 215        int slash = 1;
 216        int cnt;
 217
 218        for (cnt = 0; cnt < len; cnt++) {
 219                switch (*path++) {
 220                case '\0':
 221                        break;
 222                case '/':
 223                        if (slash)
 224                                break;
 225                        slash = 1;
 226                        continue;
 227                case '.':
 228                        continue;
 229                default:
 230                        slash = 0;
 231                        continue;
 232                }
 233                break;
 234        }
 235        return slash;
 236}
 237
 238static const char *ref_fmt[] = {
 239        "%.*s",
 240        "refs/%.*s",
 241        "refs/tags/%.*s",
 242        "refs/heads/%.*s",
 243        "refs/remotes/%.*s",
 244        "refs/remotes/%.*s/HEAD",
 245        NULL
 246};
 247
 248int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
 249{
 250        const char **p, *r;
 251        int refs_found = 0;
 252
 253        *ref = NULL;
 254        for (p = ref_fmt; *p; p++) {
 255                unsigned char sha1_from_ref[20];
 256                unsigned char *this_result;
 257
 258                this_result = refs_found ? sha1_from_ref : sha1;
 259                r = resolve_ref(mkpath(*p, len, str), this_result, 1, NULL);
 260                if (r) {
 261                        if (!refs_found++)
 262                                *ref = xstrdup(r);
 263                        if (!warn_ambiguous_refs)
 264                                break;
 265                }
 266        }
 267        return refs_found;
 268}
 269
 270static int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 271{
 272        const char **p;
 273        int logs_found = 0;
 274
 275        *log = NULL;
 276        for (p = ref_fmt; *p; p++) {
 277                struct stat st;
 278                char *path = mkpath(*p, len, str);
 279                if (!stat(git_path("logs/%s", path), &st) &&
 280                    S_ISREG(st.st_mode)) {
 281                        if (!logs_found++) {
 282                                *log = xstrdup(path);
 283                                resolve_ref(path, sha1, 0, NULL);
 284                        }
 285                        if (!warn_ambiguous_refs)
 286                                break;
 287                }
 288        }
 289        return logs_found;
 290}
 291
 292static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 293{
 294        static const char *warning = "warning: refname '%.*s' is ambiguous.\n";
 295        char *real_ref = NULL;
 296        int refs_found = 0;
 297        int at, reflog_len;
 298
 299        if (len == 40 && !get_sha1_hex(str, sha1))
 300                return 0;
 301
 302        /* basic@{time or number} format to query ref-log */
 303        reflog_len = at = 0;
 304        if (str[len-1] == '}') {
 305                for (at = 0; at < len - 1; at++) {
 306                        if (str[at] == '@' && str[at+1] == '{') {
 307                                reflog_len = (len-1) - (at+2);
 308                                len = at;
 309                                break;
 310                        }
 311                }
 312        }
 313
 314        /* Accept only unambiguous ref paths. */
 315        if (len && ambiguous_path(str, len))
 316                return -1;
 317
 318        if (!len && reflog_len) {
 319                /* allow "@{...}" to mean the current branch reflog */
 320                refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
 321        } else if (reflog_len)
 322                refs_found = dwim_log(str, len, sha1, &real_ref);
 323        else
 324                refs_found = dwim_ref(str, len, sha1, &real_ref);
 325
 326        if (!refs_found)
 327                return -1;
 328
 329        if (warn_ambiguous_refs && refs_found > 1)
 330                fprintf(stderr, warning, len, str);
 331
 332        if (reflog_len) {
 333                int nth, i;
 334                unsigned long at_time;
 335                unsigned long co_time;
 336                int co_tz, co_cnt;
 337
 338                /* Is it asking for N-th entry, or approxidate? */
 339                for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 340                        char ch = str[at+2+i];
 341                        if ('0' <= ch && ch <= '9')
 342                                nth = nth * 10 + ch - '0';
 343                        else
 344                                nth = -1;
 345                }
 346                if (0 <= nth)
 347                        at_time = 0;
 348                else
 349                        at_time = approxidate(str + at + 2);
 350                if (read_ref_at(real_ref, at_time, nth, sha1, NULL,
 351                                &co_time, &co_tz, &co_cnt)) {
 352                        if (at_time)
 353                                fprintf(stderr,
 354                                        "warning: Log for '%.*s' only goes "
 355                                        "back to %s.\n", len, str,
 356                                        show_rfc2822_date(co_time, co_tz));
 357                        else
 358                                fprintf(stderr,
 359                                        "warning: Log for '%.*s' only has "
 360                                        "%d entries.\n", len, str, co_cnt);
 361                }
 362        }
 363
 364        free(real_ref);
 365        return 0;
 366}
 367
 368static int get_sha1_1(const char *name, int len, unsigned char *sha1);
 369
 370static int get_parent(const char *name, int len,
 371                      unsigned char *result, int idx)
 372{
 373        unsigned char sha1[20];
 374        int ret = get_sha1_1(name, len, sha1);
 375        struct commit *commit;
 376        struct commit_list *p;
 377
 378        if (ret)
 379                return ret;
 380        commit = lookup_commit_reference(sha1);
 381        if (!commit)
 382                return -1;
 383        if (parse_commit(commit))
 384                return -1;
 385        if (!idx) {
 386                hashcpy(result, commit->object.sha1);
 387                return 0;
 388        }
 389        p = commit->parents;
 390        while (p) {
 391                if (!--idx) {
 392                        hashcpy(result, p->item->object.sha1);
 393                        return 0;
 394                }
 395                p = p->next;
 396        }
 397        return -1;
 398}
 399
 400static int get_nth_ancestor(const char *name, int len,
 401                            unsigned char *result, int generation)
 402{
 403        unsigned char sha1[20];
 404        int ret = get_sha1_1(name, len, sha1);
 405        if (ret)
 406                return ret;
 407
 408        while (generation--) {
 409                struct commit *commit = lookup_commit_reference(sha1);
 410
 411                if (!commit || parse_commit(commit) || !commit->parents)
 412                        return -1;
 413                hashcpy(sha1, commit->parents->item->object.sha1);
 414        }
 415        hashcpy(result, sha1);
 416        return 0;
 417}
 418
 419static int peel_onion(const char *name, int len, unsigned char *sha1)
 420{
 421        unsigned char outer[20];
 422        const char *sp;
 423        unsigned int expected_type = 0;
 424        struct object *o;
 425
 426        /*
 427         * "ref^{type}" dereferences ref repeatedly until you cannot
 428         * dereference anymore, or you get an object of given type,
 429         * whichever comes first.  "ref^{}" means just dereference
 430         * tags until you get a non-tag.  "ref^0" is a shorthand for
 431         * "ref^{commit}".  "commit^{tree}" could be used to find the
 432         * top-level tree of the given commit.
 433         */
 434        if (len < 4 || name[len-1] != '}')
 435                return -1;
 436
 437        for (sp = name + len - 1; name <= sp; sp--) {
 438                int ch = *sp;
 439                if (ch == '{' && name < sp && sp[-1] == '^')
 440                        break;
 441        }
 442        if (sp <= name)
 443                return -1;
 444
 445        sp++; /* beginning of type name, or closing brace for empty */
 446        if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
 447                expected_type = OBJ_COMMIT;
 448        else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
 449                expected_type = OBJ_TREE;
 450        else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
 451                expected_type = OBJ_BLOB;
 452        else if (sp[0] == '}')
 453                expected_type = OBJ_NONE;
 454        else
 455                return -1;
 456
 457        if (get_sha1_1(name, sp - name - 2, outer))
 458                return -1;
 459
 460        o = parse_object(outer);
 461        if (!o)
 462                return -1;
 463        if (!expected_type) {
 464                o = deref_tag(o, name, sp - name - 2);
 465                if (!o || (!o->parsed && !parse_object(o->sha1)))
 466                        return -1;
 467                hashcpy(sha1, o->sha1);
 468        }
 469        else {
 470                /* At this point, the syntax look correct, so
 471                 * if we do not get the needed object, we should
 472                 * barf.
 473                 */
 474
 475                while (1) {
 476                        if (!o || (!o->parsed && !parse_object(o->sha1)))
 477                                return -1;
 478                        if (o->type == expected_type) {
 479                                hashcpy(sha1, o->sha1);
 480                                return 0;
 481                        }
 482                        if (o->type == OBJ_TAG)
 483                                o = ((struct tag*) o)->tagged;
 484                        else if (o->type == OBJ_COMMIT)
 485                                o = &(((struct commit *) o)->tree->object);
 486                        else
 487                                return error("%.*s: expected %s type, but the object dereferences to %s type",
 488                                             len, name, typename(expected_type),
 489                                             typename(o->type));
 490                        if (!o->parsed)
 491                                parse_object(o->sha1);
 492                }
 493        }
 494        return 0;
 495}
 496
 497static int get_describe_name(const char *name, int len, unsigned char *sha1)
 498{
 499        const char *cp;
 500
 501        for (cp = name + len - 1; name + 2 <= cp; cp--) {
 502                char ch = *cp;
 503                if (hexval(ch) & ~0377) {
 504                        /* We must be looking at g in "SOMETHING-g"
 505                         * for it to be describe output.
 506                         */
 507                        if (ch == 'g' && cp[-1] == '-') {
 508                                cp++;
 509                                len -= cp - name;
 510                                return get_short_sha1(cp, len, sha1, 1);
 511                        }
 512                }
 513        }
 514        return -1;
 515}
 516
 517static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 518{
 519        int ret, has_suffix;
 520        const char *cp;
 521
 522        /* "name~3" is "name^^^",
 523         * "name~" and "name~0" are name -- not "name^0"!
 524         * "name^" is not "name^0"; it is "name^1".
 525         */
 526        has_suffix = 0;
 527        for (cp = name + len - 1; name <= cp; cp--) {
 528                int ch = *cp;
 529                if ('0' <= ch && ch <= '9')
 530                        continue;
 531                if (ch == '~' || ch == '^')
 532                        has_suffix = ch;
 533                break;
 534        }
 535
 536        if (has_suffix) {
 537                int num = 0;
 538                int len1 = cp - name;
 539                cp++;
 540                while (cp < name + len)
 541                        num = num * 10 + *cp++ - '0';
 542                if (has_suffix == '^') {
 543                        if (!num && len1 == len - 1)
 544                                num = 1;
 545                        return get_parent(name, len1, sha1, num);
 546                }
 547                /* else if (has_suffix == '~') -- goes without saying */
 548                return get_nth_ancestor(name, len1, sha1, num);
 549        }
 550
 551        ret = peel_onion(name, len, sha1);
 552        if (!ret)
 553                return 0;
 554
 555        ret = get_sha1_basic(name, len, sha1);
 556        if (!ret)
 557                return 0;
 558
 559        /* It could be describe output that is "SOMETHING-gXXXX" */
 560        ret = get_describe_name(name, len, sha1);
 561        if (!ret)
 562                return 0;
 563
 564        return get_short_sha1(name, len, sha1, 0);
 565}
 566
 567/*
 568 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
 569 * notably "xyz^" for "parent of xyz"
 570 */
 571int get_sha1(const char *name, unsigned char *sha1)
 572{
 573        int ret, bracket_depth;
 574        unsigned unused;
 575        int namelen = strlen(name);
 576        const char *cp;
 577
 578        prepare_alt_odb();
 579        ret = get_sha1_1(name, namelen, sha1);
 580        if (!ret)
 581                return ret;
 582        /* sha1:path --> object name of path in ent sha1
 583         * :path -> object name of path in index
 584         * :[0-3]:path -> object name of path in index at stage
 585         */
 586        if (name[0] == ':') {
 587                int stage = 0;
 588                struct cache_entry *ce;
 589                int pos;
 590                if (namelen < 3 ||
 591                    name[2] != ':' ||
 592                    name[1] < '0' || '3' < name[1])
 593                        cp = name + 1;
 594                else {
 595                        stage = name[1] - '0';
 596                        cp = name + 3;
 597                }
 598                namelen = namelen - (cp - name);
 599                if (!active_cache)
 600                        read_cache();
 601                if (active_nr < 0)
 602                        return -1;
 603                pos = cache_name_pos(cp, namelen);
 604                if (pos < 0)
 605                        pos = -pos - 1;
 606                while (pos < active_nr) {
 607                        ce = active_cache[pos];
 608                        if (ce_namelen(ce) != namelen ||
 609                            memcmp(ce->name, cp, namelen))
 610                                break;
 611                        if (ce_stage(ce) == stage) {
 612                                hashcpy(sha1, ce->sha1);
 613                                return 0;
 614                        }
 615                        pos++;
 616                }
 617                return -1;
 618        }
 619        for (cp = name, bracket_depth = 0; *cp; cp++) {
 620                if (*cp == '{')
 621                        bracket_depth++;
 622                else if (bracket_depth && *cp == '}')
 623                        bracket_depth--;
 624                else if (!bracket_depth && *cp == ':')
 625                        break;
 626        }
 627        if (*cp == ':') {
 628                unsigned char tree_sha1[20];
 629                if (!get_sha1_1(name, cp-name, tree_sha1))
 630                        return get_tree_entry(tree_sha1, cp+1, sha1,
 631                                              &unused);
 632        }
 633        return ret;
 634}