Andrew's git / gitweb.git / sha1_name.c
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sha1_name.con commit t5516: remove ambiguity test (1) (3ef6a1f)
   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        const unsigned char *found_sha1 = NULL;
  75        int found = 0;
  76
  77        prepare_packed_git();
  78        for (p = packed_git; p && found < 2; p = p->next) {
  79                uint32_t num, last;
  80                uint32_t first = 0;
  81                open_pack_index(p);
  82                num = p->num_objects;
  83                last = num;
  84                while (first < last) {
  85                        uint32_t mid = (first + last) / 2;
  86                        const unsigned char *now;
  87                        int cmp;
  88
  89                        now = nth_packed_object_sha1(p, mid);
  90                        cmp = hashcmp(match, now);
  91                        if (!cmp) {
  92                                first = mid;
  93                                break;
  94                        }
  95                        if (cmp > 0) {
  96                                first = mid+1;
  97                                continue;
  98                        }
  99                        last = mid;
 100                }
 101                if (first < num) {
 102                        const unsigned char *now, *next;
 103                       now = nth_packed_object_sha1(p, first);
 104                        if (match_sha(len, match, now)) {
 105                                next = nth_packed_object_sha1(p, first+1);
 106                               if (!next|| !match_sha(len, match, next)) {
 107                                        /* unique within this pack */
 108                                        if (!found) {
 109                                                found_sha1 = now;
 110                                                found++;
 111                                        }
 112                                        else if (hashcmp(found_sha1, now)) {
 113                                                found = 2;
 114                                                break;
 115                                        }
 116                                }
 117                                else {
 118                                        /* not even unique within this pack */
 119                                        found = 2;
 120                                        break;
 121                                }
 122                        }
 123                }
 124        }
 125        if (found == 1)
 126                hashcpy(sha1, found_sha1);
 127        return found;
 128}
 129
 130#define SHORT_NAME_NOT_FOUND (-1)
 131#define SHORT_NAME_AMBIGUOUS (-2)
 132
 133static int find_unique_short_object(int len, char *canonical,
 134                                    unsigned char *res, unsigned char *sha1)
 135{
 136        int has_unpacked, has_packed;
 137        unsigned char unpacked_sha1[20], packed_sha1[20];
 138
 139        prepare_alt_odb();
 140        has_unpacked = find_short_object_filename(len, canonical, unpacked_sha1);
 141        has_packed = find_short_packed_object(len, res, packed_sha1);
 142        if (!has_unpacked && !has_packed)
 143                return SHORT_NAME_NOT_FOUND;
 144        if (1 < has_unpacked || 1 < has_packed)
 145                return SHORT_NAME_AMBIGUOUS;
 146        if (has_unpacked != has_packed) {
 147                hashcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1));
 148                return 0;
 149        }
 150        /* Both have unique ones -- do they match? */
 151        if (hashcmp(packed_sha1, unpacked_sha1))
 152                return SHORT_NAME_AMBIGUOUS;
 153        hashcpy(sha1, packed_sha1);
 154        return 0;
 155}
 156
 157static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 158                          int quietly)
 159{
 160        int i, status;
 161        char canonical[40];
 162        unsigned char res[20];
 163
 164        if (len < MINIMUM_ABBREV || len > 40)
 165                return -1;
 166        hashclr(res);
 167        memset(canonical, 'x', 40);
 168        for (i = 0; i < len ;i++) {
 169                unsigned char c = name[i];
 170                unsigned char val;
 171                if (c >= '0' && c <= '9')
 172                        val = c - '0';
 173                else if (c >= 'a' && c <= 'f')
 174                        val = c - 'a' + 10;
 175                else if (c >= 'A' && c <='F') {
 176                        val = c - 'A' + 10;
 177                        c -= 'A' - 'a';
 178                }
 179                else
 180                        return -1;
 181                canonical[i] = c;
 182                if (!(i & 1))
 183                        val <<= 4;
 184                res[i >> 1] |= val;
 185        }
 186
 187        status = find_unique_short_object(i, canonical, res, sha1);
 188        if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
 189                return error("short SHA1 %.*s is ambiguous.", len, canonical);
 190        return status;
 191}
 192
 193const char *find_unique_abbrev(const unsigned char *sha1, int len)
 194{
 195        int status, is_null;
 196        static char hex[41];
 197
 198        is_null = is_null_sha1(sha1);
 199        memcpy(hex, sha1_to_hex(sha1), 40);
 200        if (len == 40 || !len)
 201                return hex;
 202        while (len < 40) {
 203                unsigned char sha1_ret[20];
 204                status = get_short_sha1(hex, len, sha1_ret, 1);
 205                if (!status ||
 206                    (is_null && status != SHORT_NAME_AMBIGUOUS)) {
 207                        hex[len] = 0;
 208                        return hex;
 209                }
 210                if (status != SHORT_NAME_AMBIGUOUS)
 211                        return NULL;
 212                len++;
 213        }
 214        return NULL;
 215}
 216
 217static int ambiguous_path(const char *path, int len)
 218{
 219        int slash = 1;
 220        int cnt;
 221
 222        for (cnt = 0; cnt < len; cnt++) {
 223                switch (*path++) {
 224                case '\0':
 225                        break;
 226                case '/':
 227                        if (slash)
 228                                break;
 229                        slash = 1;
 230                        continue;
 231                case '.':
 232                        continue;
 233                default:
 234                        slash = 0;
 235                        continue;
 236                }
 237                break;
 238        }
 239        return slash;
 240}
 241
 242int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
 243{
 244        const char **p, *r;
 245        int refs_found = 0;
 246
 247        *ref = NULL;
 248        for (p = ref_rev_parse_rules; *p; p++) {
 249                unsigned char sha1_from_ref[20];
 250                unsigned char *this_result;
 251
 252                this_result = refs_found ? sha1_from_ref : sha1;
 253                r = resolve_ref(mkpath(*p, len, str), this_result, 1, NULL);
 254                if (r) {
 255                        if (!refs_found++)
 256                                *ref = xstrdup(r);
 257                        if (!warn_ambiguous_refs)
 258                                break;
 259                }
 260        }
 261        return refs_found;
 262}
 263
 264int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 265{
 266        const char **p;
 267        int logs_found = 0;
 268
 269        *log = NULL;
 270        for (p = ref_rev_parse_rules; *p; p++) {
 271                struct stat st;
 272                unsigned char hash[20];
 273                char path[PATH_MAX];
 274                const char *ref, *it;
 275
 276                strcpy(path, mkpath(*p, len, str));
 277                ref = resolve_ref(path, hash, 0, NULL);
 278                if (!ref)
 279                        continue;
 280                if (!stat(git_path("logs/%s", path), &st) &&
 281                    S_ISREG(st.st_mode))
 282                        it = path;
 283                else if (strcmp(ref, path) &&
 284                         !stat(git_path("logs/%s", ref), &st) &&
 285                         S_ISREG(st.st_mode))
 286                        it = ref;
 287                else
 288                        continue;
 289                if (!logs_found++) {
 290                        *log = xstrdup(it);
 291                        hashcpy(sha1, hash);
 292                }
 293                if (!warn_ambiguous_refs)
 294                        break;
 295        }
 296        return logs_found;
 297}
 298
 299static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 300{
 301        static const char *warning = "warning: refname '%.*s' is ambiguous.\n";
 302        char *real_ref = NULL;
 303        int refs_found = 0;
 304        int at, reflog_len;
 305
 306        if (len == 40 && !get_sha1_hex(str, sha1))
 307                return 0;
 308
 309        /* basic@{time or number} format to query ref-log */
 310        reflog_len = at = 0;
 311        if (str[len-1] == '}') {
 312                for (at = 0; at < len - 1; at++) {
 313                        if (str[at] == '@' && str[at+1] == '{') {
 314                                reflog_len = (len-1) - (at+2);
 315                                len = at;
 316                                break;
 317                        }
 318                }
 319        }
 320
 321        /* Accept only unambiguous ref paths. */
 322        if (len && ambiguous_path(str, len))
 323                return -1;
 324
 325        if (!len && reflog_len) {
 326                /* allow "@{...}" to mean the current branch reflog */
 327                refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
 328        } else if (reflog_len)
 329                refs_found = dwim_log(str, len, sha1, &real_ref);
 330        else
 331                refs_found = dwim_ref(str, len, sha1, &real_ref);
 332
 333        if (!refs_found)
 334                return -1;
 335
 336        if (warn_ambiguous_refs && refs_found > 1)
 337                fprintf(stderr, warning, len, str);
 338
 339        if (reflog_len) {
 340                int nth, i;
 341                unsigned long at_time;
 342                unsigned long co_time;
 343                int co_tz, co_cnt;
 344
 345                /* Is it asking for N-th entry, or approxidate? */
 346                for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 347                        char ch = str[at+2+i];
 348                        if ('0' <= ch && ch <= '9')
 349                                nth = nth * 10 + ch - '0';
 350                        else
 351                                nth = -1;
 352                }
 353                if (0 <= nth)
 354                        at_time = 0;
 355                else
 356                        at_time = approxidate(str + at + 2);
 357                if (read_ref_at(real_ref, at_time, nth, sha1, NULL,
 358                                &co_time, &co_tz, &co_cnt)) {
 359                        if (at_time)
 360                                fprintf(stderr,
 361                                        "warning: Log for '%.*s' only goes "
 362                                        "back to %s.\n", len, str,
 363                                        show_date(co_time, co_tz, DATE_RFC2822));
 364                        else
 365                                fprintf(stderr,
 366                                        "warning: Log for '%.*s' only has "
 367                                        "%d entries.\n", len, str, co_cnt);
 368                }
 369        }
 370
 371        free(real_ref);
 372        return 0;
 373}
 374
 375static int get_sha1_1(const char *name, int len, unsigned char *sha1);
 376
 377static int get_parent(const char *name, int len,
 378                      unsigned char *result, int idx)
 379{
 380        unsigned char sha1[20];
 381        int ret = get_sha1_1(name, len, sha1);
 382        struct commit *commit;
 383        struct commit_list *p;
 384
 385        if (ret)
 386                return ret;
 387        commit = lookup_commit_reference(sha1);
 388        if (!commit)
 389                return -1;
 390        if (parse_commit(commit))
 391                return -1;
 392        if (!idx) {
 393                hashcpy(result, commit->object.sha1);
 394                return 0;
 395        }
 396        p = commit->parents;
 397        while (p) {
 398                if (!--idx) {
 399                        hashcpy(result, p->item->object.sha1);
 400                        return 0;
 401                }
 402                p = p->next;
 403        }
 404        return -1;
 405}
 406
 407static int get_nth_ancestor(const char *name, int len,
 408                            unsigned char *result, int generation)
 409{
 410        unsigned char sha1[20];
 411        struct commit *commit;
 412        int ret;
 413
 414        ret = get_sha1_1(name, len, sha1);
 415        if (ret)
 416                return ret;
 417        commit = lookup_commit_reference(sha1);
 418        if (!commit)
 419                return -1;
 420
 421        while (generation--) {
 422                if (parse_commit(commit) || !commit->parents)
 423                        return -1;
 424                commit = commit->parents->item;
 425        }
 426        hashcpy(result, commit->object.sha1);
 427        return 0;
 428}
 429
 430static int peel_onion(const char *name, int len, unsigned char *sha1)
 431{
 432        unsigned char outer[20];
 433        const char *sp;
 434        unsigned int expected_type = 0;
 435        struct object *o;
 436
 437        /*
 438         * "ref^{type}" dereferences ref repeatedly until you cannot
 439         * dereference anymore, or you get an object of given type,
 440         * whichever comes first.  "ref^{}" means just dereference
 441         * tags until you get a non-tag.  "ref^0" is a shorthand for
 442         * "ref^{commit}".  "commit^{tree}" could be used to find the
 443         * top-level tree of the given commit.
 444         */
 445        if (len < 4 || name[len-1] != '}')
 446                return -1;
 447
 448        for (sp = name + len - 1; name <= sp; sp--) {
 449                int ch = *sp;
 450                if (ch == '{' && name < sp && sp[-1] == '^')
 451                        break;
 452        }
 453        if (sp <= name)
 454                return -1;
 455
 456        sp++; /* beginning of type name, or closing brace for empty */
 457        if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
 458                expected_type = OBJ_COMMIT;
 459        else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
 460                expected_type = OBJ_TREE;
 461        else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
 462                expected_type = OBJ_BLOB;
 463        else if (sp[0] == '}')
 464                expected_type = OBJ_NONE;
 465        else
 466                return -1;
 467
 468        if (get_sha1_1(name, sp - name - 2, outer))
 469                return -1;
 470
 471        o = parse_object(outer);
 472        if (!o)
 473                return -1;
 474        if (!expected_type) {
 475                o = deref_tag(o, name, sp - name - 2);
 476                if (!o || (!o->parsed && !parse_object(o->sha1)))
 477                        return -1;
 478                hashcpy(sha1, o->sha1);
 479        }
 480        else {
 481                /* At this point, the syntax look correct, so
 482                 * if we do not get the needed object, we should
 483                 * barf.
 484                 */
 485
 486                while (1) {
 487                        if (!o || (!o->parsed && !parse_object(o->sha1)))
 488                                return -1;
 489                        if (o->type == expected_type) {
 490                                hashcpy(sha1, o->sha1);
 491                                return 0;
 492                        }
 493                        if (o->type == OBJ_TAG)
 494                                o = ((struct tag*) o)->tagged;
 495                        else if (o->type == OBJ_COMMIT)
 496                                o = &(((struct commit *) o)->tree->object);
 497                        else
 498                                return error("%.*s: expected %s type, but the object dereferences to %s type",
 499                                             len, name, typename(expected_type),
 500                                             typename(o->type));
 501                        if (!o->parsed)
 502                                parse_object(o->sha1);
 503                }
 504        }
 505        return 0;
 506}
 507
 508static int get_describe_name(const char *name, int len, unsigned char *sha1)
 509{
 510        const char *cp;
 511
 512        for (cp = name + len - 1; name + 2 <= cp; cp--) {
 513                char ch = *cp;
 514                if (hexval(ch) & ~0377) {
 515                        /* We must be looking at g in "SOMETHING-g"
 516                         * for it to be describe output.
 517                         */
 518                        if (ch == 'g' && cp[-1] == '-') {
 519                                cp++;
 520                                len -= cp - name;
 521                                return get_short_sha1(cp, len, sha1, 1);
 522                        }
 523                }
 524        }
 525        return -1;
 526}
 527
 528static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 529{
 530        int ret, has_suffix;
 531        const char *cp;
 532
 533        /*
 534         * "name~3" is "name^^^", "name~" is "name~1", and "name^" is "name^1".
 535         */
 536        has_suffix = 0;
 537        for (cp = name + len - 1; name <= cp; cp--) {
 538                int ch = *cp;
 539                if ('0' <= ch && ch <= '9')
 540                        continue;
 541                if (ch == '~' || ch == '^')
 542                        has_suffix = ch;
 543                break;
 544        }
 545
 546        if (has_suffix) {
 547                int num = 0;
 548                int len1 = cp - name;
 549                cp++;
 550                while (cp < name + len)
 551                        num = num * 10 + *cp++ - '0';
 552                if (!num && len1 == len - 1)
 553                        num = 1;
 554                if (has_suffix == '^')
 555                        return get_parent(name, len1, sha1, num);
 556                /* else if (has_suffix == '~') -- goes without saying */
 557                return get_nth_ancestor(name, len1, sha1, num);
 558        }
 559
 560        ret = peel_onion(name, len, sha1);
 561        if (!ret)
 562                return 0;
 563
 564        ret = get_sha1_basic(name, len, sha1);
 565        if (!ret)
 566                return 0;
 567
 568        /* It could be describe output that is "SOMETHING-gXXXX" */
 569        ret = get_describe_name(name, len, sha1);
 570        if (!ret)
 571                return 0;
 572
 573        return get_short_sha1(name, len, sha1, 0);
 574}
 575
 576static int handle_one_ref(const char *path,
 577                const unsigned char *sha1, int flag, void *cb_data)
 578{
 579        struct commit_list **list = cb_data;
 580        struct object *object = parse_object(sha1);
 581        if (!object)
 582                return 0;
 583        if (object->type == OBJ_TAG)
 584                object = deref_tag(object, path, strlen(path));
 585        if (object->type != OBJ_COMMIT)
 586                return 0;
 587        insert_by_date((struct commit *)object, list);
 588        return 0;
 589}
 590
 591/*
 592 * This interprets names like ':/Initial revision of "git"' by searching
 593 * through history and returning the first commit whose message starts
 594 * with the given string.
 595 *
 596 * For future extension, ':/!' is reserved. If you want to match a message
 597 * beginning with a '!', you have to repeat the exclamation mark.
 598 */
 599
 600#define ONELINE_SEEN (1u<<20)
 601static int get_sha1_oneline(const char *prefix, unsigned char *sha1)
 602{
 603        struct commit_list *list = NULL, *backup = NULL, *l;
 604        int retval = -1;
 605        char *temp_commit_buffer = NULL;
 606
 607        if (prefix[0] == '!') {
 608                if (prefix[1] != '!')
 609                        die ("Invalid search pattern: %s", prefix);
 610                prefix++;
 611        }
 612        for_each_ref(handle_one_ref, &list);
 613        for (l = list; l; l = l->next)
 614                commit_list_insert(l->item, &backup);
 615        while (list) {
 616                char *p;
 617                struct commit *commit;
 618                enum object_type type;
 619                unsigned long size;
 620
 621                commit = pop_most_recent_commit(&list, ONELINE_SEEN);
 622                parse_object(commit->object.sha1);
 623                if (temp_commit_buffer)
 624                        free(temp_commit_buffer);
 625                if (commit->buffer)
 626                        p = commit->buffer;
 627                else {
 628                        p = read_sha1_file(commit->object.sha1, &type, &size);
 629                        if (!p)
 630                                continue;
 631                        temp_commit_buffer = p;
 632                }
 633                if (!(p = strstr(p, "\n\n")))
 634                        continue;
 635                if (!prefixcmp(p + 2, prefix)) {
 636                        hashcpy(sha1, commit->object.sha1);
 637                        retval = 0;
 638                        break;
 639                }
 640        }
 641        if (temp_commit_buffer)
 642                free(temp_commit_buffer);
 643        free_commit_list(list);
 644        for (l = backup; l; l = l->next)
 645                clear_commit_marks(l->item, ONELINE_SEEN);
 646        return retval;
 647}
 648
 649/*
 650 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
 651 * notably "xyz^" for "parent of xyz"
 652 */
 653int get_sha1(const char *name, unsigned char *sha1)
 654{
 655        unsigned unused;
 656        return get_sha1_with_mode(name, sha1, &unused);
 657}
 658
 659int get_sha1_with_mode(const char *name, unsigned char *sha1, unsigned *mode)
 660{
 661        int ret, bracket_depth;
 662        int namelen = strlen(name);
 663        const char *cp;
 664
 665        *mode = S_IFINVALID;
 666        ret = get_sha1_1(name, namelen, sha1);
 667        if (!ret)
 668                return ret;
 669        /* sha1:path --> object name of path in ent sha1
 670         * :path -> object name of path in index
 671         * :[0-3]:path -> object name of path in index at stage
 672         */
 673        if (name[0] == ':') {
 674                int stage = 0;
 675                struct cache_entry *ce;
 676                int pos;
 677                if (namelen > 2 && name[1] == '/')
 678                        return get_sha1_oneline(name + 2, sha1);
 679                if (namelen < 3 ||
 680                    name[2] != ':' ||
 681                    name[1] < '0' || '3' < name[1])
 682                        cp = name + 1;
 683                else {
 684                        stage = name[1] - '0';
 685                        cp = name + 3;
 686                }
 687                namelen = namelen - (cp - name);
 688                if (!active_cache)
 689                        read_cache();
 690                pos = cache_name_pos(cp, namelen);
 691                if (pos < 0)
 692                        pos = -pos - 1;
 693                while (pos < active_nr) {
 694                        ce = active_cache[pos];
 695                        if (ce_namelen(ce) != namelen ||
 696                            memcmp(ce->name, cp, namelen))
 697                                break;
 698                        if (ce_stage(ce) == stage) {
 699                                hashcpy(sha1, ce->sha1);
 700                                *mode = ntohl(ce->ce_mode);
 701                                return 0;
 702                        }
 703                        pos++;
 704                }
 705                return -1;
 706        }
 707        for (cp = name, bracket_depth = 0; *cp; cp++) {
 708                if (*cp == '{')
 709                        bracket_depth++;
 710                else if (bracket_depth && *cp == '}')
 711                        bracket_depth--;
 712                else if (!bracket_depth && *cp == ':')
 713                        break;
 714        }
 715        if (*cp == ':') {
 716                unsigned char tree_sha1[20];
 717                if (!get_sha1_1(name, cp-name, tree_sha1))
 718                        return get_tree_entry(tree_sha1, cp+1, sha1,
 719                                              mode);
 720        }
 721        return ret;
 722}