Andrew's git / gitweb.git / sha1_name.c
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sha1_name.con commit Attempt to delay prepare_alt_odb during get_sha1 (693d2bc)
   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 = p->num_objects;
  80                uint32_t first = 0, last = num;
  81                while (first < last) {
  82                        uint32_t mid = (first + last) / 2;
  83                        const unsigned char *now;
  84                        int cmp;
  85
  86                        now = nth_packed_object_sha1(p, mid);
  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                        const unsigned char *now, *next;
 100                       now = nth_packed_object_sha1(p, first);
 101                        if (match_sha(len, match, now)) {
 102                                next = nth_packed_object_sha1(p, first+1);
 103                               if (!next|| !match_sha(len, match, next)) {
 104                                        /* unique within this pack */
 105                                        if (!found) {
 106                                                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        prepare_alt_odb();
 137        has_unpacked = find_short_object_filename(len, canonical, unpacked_sha1);
 138        has_packed = find_short_packed_object(len, res, packed_sha1);
 139        if (!has_unpacked && !has_packed)
 140                return SHORT_NAME_NOT_FOUND;
 141        if (1 < has_unpacked || 1 < has_packed)
 142                return SHORT_NAME_AMBIGUOUS;
 143        if (has_unpacked != has_packed) {
 144                hashcpy(sha1, (has_packed ? packed_sha1 : unpacked_sha1));
 145                return 0;
 146        }
 147        /* Both have unique ones -- do they match? */
 148        if (hashcmp(packed_sha1, unpacked_sha1))
 149                return SHORT_NAME_AMBIGUOUS;
 150        hashcpy(sha1, packed_sha1);
 151        return 0;
 152}
 153
 154static int get_short_sha1(const char *name, int len, unsigned char *sha1,
 155                          int quietly)
 156{
 157        int i, status;
 158        char canonical[40];
 159        unsigned char res[20];
 160
 161        if (len < MINIMUM_ABBREV || len > 40)
 162                return -1;
 163        hashclr(res);
 164        memset(canonical, 'x', 40);
 165        for (i = 0; i < len ;i++) {
 166                unsigned char c = name[i];
 167                unsigned char val;
 168                if (c >= '0' && c <= '9')
 169                        val = c - '0';
 170                else if (c >= 'a' && c <= 'f')
 171                        val = c - 'a' + 10;
 172                else if (c >= 'A' && c <='F') {
 173                        val = c - 'A' + 10;
 174                        c -= 'A' - 'a';
 175                }
 176                else
 177                        return -1;
 178                canonical[i] = c;
 179                if (!(i & 1))
 180                        val <<= 4;
 181                res[i >> 1] |= val;
 182        }
 183
 184        status = find_unique_short_object(i, canonical, res, sha1);
 185        if (!quietly && (status == SHORT_NAME_AMBIGUOUS))
 186                return error("short SHA1 %.*s is ambiguous.", len, canonical);
 187        return status;
 188}
 189
 190const char *find_unique_abbrev(const unsigned char *sha1, int len)
 191{
 192        int status, is_null;
 193        static char hex[41];
 194
 195        is_null = is_null_sha1(sha1);
 196        memcpy(hex, sha1_to_hex(sha1), 40);
 197        if (len == 40 || !len)
 198                return hex;
 199        while (len < 40) {
 200                unsigned char sha1_ret[20];
 201                status = get_short_sha1(hex, len, sha1_ret, 1);
 202                if (!status ||
 203                    (is_null && status != SHORT_NAME_AMBIGUOUS)) {
 204                        hex[len] = 0;
 205                        return hex;
 206                }
 207                if (status != SHORT_NAME_AMBIGUOUS)
 208                        return NULL;
 209                len++;
 210        }
 211        return NULL;
 212}
 213
 214static int ambiguous_path(const char *path, int len)
 215{
 216        int slash = 1;
 217        int cnt;
 218
 219        for (cnt = 0; cnt < len; cnt++) {
 220                switch (*path++) {
 221                case '\0':
 222                        break;
 223                case '/':
 224                        if (slash)
 225                                break;
 226                        slash = 1;
 227                        continue;
 228                case '.':
 229                        continue;
 230                default:
 231                        slash = 0;
 232                        continue;
 233                }
 234                break;
 235        }
 236        return slash;
 237}
 238
 239static const char *ref_fmt[] = {
 240        "%.*s",
 241        "refs/%.*s",
 242        "refs/tags/%.*s",
 243        "refs/heads/%.*s",
 244        "refs/remotes/%.*s",
 245        "refs/remotes/%.*s/HEAD",
 246        NULL
 247};
 248
 249int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
 250{
 251        const char **p, *r;
 252        int refs_found = 0;
 253
 254        *ref = NULL;
 255        for (p = ref_fmt; *p; p++) {
 256                unsigned char sha1_from_ref[20];
 257                unsigned char *this_result;
 258
 259                this_result = refs_found ? sha1_from_ref : sha1;
 260                r = resolve_ref(mkpath(*p, len, str), this_result, 1, NULL);
 261                if (r) {
 262                        if (!refs_found++)
 263                                *ref = xstrdup(r);
 264                        if (!warn_ambiguous_refs)
 265                                break;
 266                }
 267        }
 268        return refs_found;
 269}
 270
 271int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 272{
 273        const char **p;
 274        int logs_found = 0;
 275
 276        *log = NULL;
 277        for (p = ref_fmt; *p; p++) {
 278                struct stat st;
 279                unsigned char hash[20];
 280                char path[PATH_MAX];
 281                const char *ref, *it;
 282
 283                strcpy(path, mkpath(*p, len, str));
 284                ref = resolve_ref(path, hash, 0, NULL);
 285                if (!ref)
 286                        continue;
 287                if (!stat(git_path("logs/%s", path), &st) &&
 288                    S_ISREG(st.st_mode))
 289                        it = path;
 290                else if (strcmp(ref, path) &&
 291                         !stat(git_path("logs/%s", ref), &st) &&
 292                         S_ISREG(st.st_mode))
 293                        it = ref;
 294                else
 295                        continue;
 296                if (!logs_found++) {
 297                        *log = xstrdup(it);
 298                        hashcpy(sha1, hash);
 299                }
 300                if (!warn_ambiguous_refs)
 301                        break;
 302        }
 303        return logs_found;
 304}
 305
 306static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 307{
 308        static const char *warning = "warning: refname '%.*s' is ambiguous.\n";
 309        char *real_ref = NULL;
 310        int refs_found = 0;
 311        int at, reflog_len;
 312
 313        if (len == 40 && !get_sha1_hex(str, sha1))
 314                return 0;
 315
 316        /* basic@{time or number} format to query ref-log */
 317        reflog_len = at = 0;
 318        if (str[len-1] == '}') {
 319                for (at = 0; at < len - 1; at++) {
 320                        if (str[at] == '@' && str[at+1] == '{') {
 321                                reflog_len = (len-1) - (at+2);
 322                                len = at;
 323                                break;
 324                        }
 325                }
 326        }
 327
 328        /* Accept only unambiguous ref paths. */
 329        if (len && ambiguous_path(str, len))
 330                return -1;
 331
 332        if (!len && reflog_len) {
 333                /* allow "@{...}" to mean the current branch reflog */
 334                refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
 335        } else if (reflog_len)
 336                refs_found = dwim_log(str, len, sha1, &real_ref);
 337        else
 338                refs_found = dwim_ref(str, len, sha1, &real_ref);
 339
 340        if (!refs_found)
 341                return -1;
 342
 343        if (warn_ambiguous_refs && refs_found > 1)
 344                fprintf(stderr, warning, len, str);
 345
 346        if (reflog_len) {
 347                int nth, i;
 348                unsigned long at_time;
 349                unsigned long co_time;
 350                int co_tz, co_cnt;
 351
 352                /* Is it asking for N-th entry, or approxidate? */
 353                for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 354                        char ch = str[at+2+i];
 355                        if ('0' <= ch && ch <= '9')
 356                                nth = nth * 10 + ch - '0';
 357                        else
 358                                nth = -1;
 359                }
 360                if (0 <= nth)
 361                        at_time = 0;
 362                else
 363                        at_time = approxidate(str + at + 2);
 364                if (read_ref_at(real_ref, at_time, nth, sha1, NULL,
 365                                &co_time, &co_tz, &co_cnt)) {
 366                        if (at_time)
 367                                fprintf(stderr,
 368                                        "warning: Log for '%.*s' only goes "
 369                                        "back to %s.\n", len, str,
 370                                        show_rfc2822_date(co_time, co_tz));
 371                        else
 372                                fprintf(stderr,
 373                                        "warning: Log for '%.*s' only has "
 374                                        "%d entries.\n", len, str, co_cnt);
 375                }
 376        }
 377
 378        free(real_ref);
 379        return 0;
 380}
 381
 382static int get_sha1_1(const char *name, int len, unsigned char *sha1);
 383
 384static int get_parent(const char *name, int len,
 385                      unsigned char *result, int idx)
 386{
 387        unsigned char sha1[20];
 388        int ret = get_sha1_1(name, len, sha1);
 389        struct commit *commit;
 390        struct commit_list *p;
 391
 392        if (ret)
 393                return ret;
 394        commit = lookup_commit_reference(sha1);
 395        if (!commit)
 396                return -1;
 397        if (parse_commit(commit))
 398                return -1;
 399        if (!idx) {
 400                hashcpy(result, commit->object.sha1);
 401                return 0;
 402        }
 403        p = commit->parents;
 404        while (p) {
 405                if (!--idx) {
 406                        hashcpy(result, p->item->object.sha1);
 407                        return 0;
 408                }
 409                p = p->next;
 410        }
 411        return -1;
 412}
 413
 414static int get_nth_ancestor(const char *name, int len,
 415                            unsigned char *result, int generation)
 416{
 417        unsigned char sha1[20];
 418        int ret = get_sha1_1(name, len, sha1);
 419        if (ret)
 420                return ret;
 421
 422        while (generation--) {
 423                struct commit *commit = lookup_commit_reference(sha1);
 424
 425                if (!commit || parse_commit(commit) || !commit->parents)
 426                        return -1;
 427                hashcpy(sha1, commit->parents->item->object.sha1);
 428        }
 429        hashcpy(result, sha1);
 430        return 0;
 431}
 432
 433static int peel_onion(const char *name, int len, unsigned char *sha1)
 434{
 435        unsigned char outer[20];
 436        const char *sp;
 437        unsigned int expected_type = 0;
 438        struct object *o;
 439
 440        /*
 441         * "ref^{type}" dereferences ref repeatedly until you cannot
 442         * dereference anymore, or you get an object of given type,
 443         * whichever comes first.  "ref^{}" means just dereference
 444         * tags until you get a non-tag.  "ref^0" is a shorthand for
 445         * "ref^{commit}".  "commit^{tree}" could be used to find the
 446         * top-level tree of the given commit.
 447         */
 448        if (len < 4 || name[len-1] != '}')
 449                return -1;
 450
 451        for (sp = name + len - 1; name <= sp; sp--) {
 452                int ch = *sp;
 453                if (ch == '{' && name < sp && sp[-1] == '^')
 454                        break;
 455        }
 456        if (sp <= name)
 457                return -1;
 458
 459        sp++; /* beginning of type name, or closing brace for empty */
 460        if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
 461                expected_type = OBJ_COMMIT;
 462        else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
 463                expected_type = OBJ_TREE;
 464        else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
 465                expected_type = OBJ_BLOB;
 466        else if (sp[0] == '}')
 467                expected_type = OBJ_NONE;
 468        else
 469                return -1;
 470
 471        if (get_sha1_1(name, sp - name - 2, outer))
 472                return -1;
 473
 474        o = parse_object(outer);
 475        if (!o)
 476                return -1;
 477        if (!expected_type) {
 478                o = deref_tag(o, name, sp - name - 2);
 479                if (!o || (!o->parsed && !parse_object(o->sha1)))
 480                        return -1;
 481                hashcpy(sha1, o->sha1);
 482        }
 483        else {
 484                /* At this point, the syntax look correct, so
 485                 * if we do not get the needed object, we should
 486                 * barf.
 487                 */
 488
 489                while (1) {
 490                        if (!o || (!o->parsed && !parse_object(o->sha1)))
 491                                return -1;
 492                        if (o->type == expected_type) {
 493                                hashcpy(sha1, o->sha1);
 494                                return 0;
 495                        }
 496                        if (o->type == OBJ_TAG)
 497                                o = ((struct tag*) o)->tagged;
 498                        else if (o->type == OBJ_COMMIT)
 499                                o = &(((struct commit *) o)->tree->object);
 500                        else
 501                                return error("%.*s: expected %s type, but the object dereferences to %s type",
 502                                             len, name, typename(expected_type),
 503                                             typename(o->type));
 504                        if (!o->parsed)
 505                                parse_object(o->sha1);
 506                }
 507        }
 508        return 0;
 509}
 510
 511static int get_describe_name(const char *name, int len, unsigned char *sha1)
 512{
 513        const char *cp;
 514
 515        for (cp = name + len - 1; name + 2 <= cp; cp--) {
 516                char ch = *cp;
 517                if (hexval(ch) & ~0377) {
 518                        /* We must be looking at g in "SOMETHING-g"
 519                         * for it to be describe output.
 520                         */
 521                        if (ch == 'g' && cp[-1] == '-') {
 522                                cp++;
 523                                len -= cp - name;
 524                                return get_short_sha1(cp, len, sha1, 1);
 525                        }
 526                }
 527        }
 528        return -1;
 529}
 530
 531static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 532{
 533        int ret, has_suffix;
 534        const char *cp;
 535
 536        /* "name~3" is "name^^^",
 537         * "name~" and "name~0" are name -- not "name^0"!
 538         * "name^" is not "name^0"; it is "name^1".
 539         */
 540        has_suffix = 0;
 541        for (cp = name + len - 1; name <= cp; cp--) {
 542                int ch = *cp;
 543                if ('0' <= ch && ch <= '9')
 544                        continue;
 545                if (ch == '~' || ch == '^')
 546                        has_suffix = ch;
 547                break;
 548        }
 549
 550        if (has_suffix) {
 551                int num = 0;
 552                int len1 = cp - name;
 553                cp++;
 554                while (cp < name + len)
 555                        num = num * 10 + *cp++ - '0';
 556                if (has_suffix == '^') {
 557                        if (!num && len1 == len - 1)
 558                                num = 1;
 559                        return get_parent(name, len1, sha1, num);
 560                }
 561                /* else if (has_suffix == '~') -- goes without saying */
 562                return get_nth_ancestor(name, len1, sha1, num);
 563        }
 564
 565        ret = peel_onion(name, len, sha1);
 566        if (!ret)
 567                return 0;
 568
 569        ret = get_sha1_basic(name, len, sha1);
 570        if (!ret)
 571                return 0;
 572
 573        /* It could be describe output that is "SOMETHING-gXXXX" */
 574        ret = get_describe_name(name, len, sha1);
 575        if (!ret)
 576                return 0;
 577
 578        return get_short_sha1(name, len, sha1, 0);
 579}
 580
 581static int handle_one_ref(const char *path,
 582                const unsigned char *sha1, int flag, void *cb_data)
 583{
 584        struct commit_list **list = cb_data;
 585        struct object *object = parse_object(sha1);
 586        if (!object)
 587                return 0;
 588        if (object->type == OBJ_TAG)
 589                object = deref_tag(object, path, strlen(path));
 590        if (object->type != OBJ_COMMIT)
 591                return 0;
 592        insert_by_date((struct commit *)object, list);
 593        return 0;
 594}
 595
 596/*
 597 * This interprets names like ':/Initial revision of "git"' by searching
 598 * through history and returning the first commit whose message starts
 599 * with the given string.
 600 *
 601 * For future extension, ':/!' is reserved. If you want to match a message
 602 * beginning with a '!', you have to repeat the exclamation mark.
 603 */
 604
 605#define ONELINE_SEEN (1u<<20)
 606static int get_sha1_oneline(const char *prefix, unsigned char *sha1)
 607{
 608        struct commit_list *list = NULL, *backup = NULL, *l;
 609        int retval = -1;
 610
 611        if (prefix[0] == '!') {
 612                if (prefix[1] != '!')
 613                        die ("Invalid search pattern: %s", prefix);
 614                prefix++;
 615        }
 616        if (!save_commit_buffer)
 617                return error("Could not expand oneline-name.");
 618        for_each_ref(handle_one_ref, &list);
 619        for (l = list; l; l = l->next)
 620                commit_list_insert(l->item, &backup);
 621        while (list) {
 622                char *p;
 623                struct commit *commit;
 624
 625                commit = pop_most_recent_commit(&list, ONELINE_SEEN);
 626                parse_object(commit->object.sha1);
 627                if (!commit->buffer || !(p = strstr(commit->buffer, "\n\n")))
 628                        continue;
 629                if (!prefixcmp(p + 2, prefix)) {
 630                        hashcpy(sha1, commit->object.sha1);
 631                        retval = 0;
 632                        break;
 633                }
 634        }
 635        free_commit_list(list);
 636        for (l = backup; l; l = l->next)
 637                clear_commit_marks(l->item, ONELINE_SEEN);
 638        return retval;
 639}
 640
 641/*
 642 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
 643 * notably "xyz^" for "parent of xyz"
 644 */
 645int get_sha1(const char *name, unsigned char *sha1)
 646{
 647        unsigned unused;
 648        return get_sha1_with_mode(name, sha1, &unused);
 649}
 650
 651int get_sha1_with_mode(const char *name, unsigned char *sha1, unsigned *mode)
 652{
 653        int ret, bracket_depth;
 654        int namelen = strlen(name);
 655        const char *cp;
 656
 657        *mode = S_IFINVALID;
 658        ret = get_sha1_1(name, namelen, sha1);
 659        if (!ret)
 660                return ret;
 661        /* sha1:path --> object name of path in ent sha1
 662         * :path -> object name of path in index
 663         * :[0-3]:path -> object name of path in index at stage
 664         */
 665        if (name[0] == ':') {
 666                int stage = 0;
 667                struct cache_entry *ce;
 668                int pos;
 669                if (namelen > 2 && name[1] == '/')
 670                        return get_sha1_oneline(name + 2, sha1);
 671                if (namelen < 3 ||
 672                    name[2] != ':' ||
 673                    name[1] < '0' || '3' < name[1])
 674                        cp = name + 1;
 675                else {
 676                        stage = name[1] - '0';
 677                        cp = name + 3;
 678                }
 679                namelen = namelen - (cp - name);
 680                if (!active_cache)
 681                        read_cache();
 682                if (active_nr < 0)
 683                        return -1;
 684                pos = cache_name_pos(cp, namelen);
 685                if (pos < 0)
 686                        pos = -pos - 1;
 687                while (pos < active_nr) {
 688                        ce = active_cache[pos];
 689                        if (ce_namelen(ce) != namelen ||
 690                            memcmp(ce->name, cp, namelen))
 691                                break;
 692                        if (ce_stage(ce) == stage) {
 693                                hashcpy(sha1, ce->sha1);
 694                                *mode = ntohl(ce->ce_mode);
 695                                return 0;
 696                        }
 697                        pos++;
 698                }
 699                return -1;
 700        }
 701        for (cp = name, bracket_depth = 0; *cp; cp++) {
 702                if (*cp == '{')
 703                        bracket_depth++;
 704                else if (bracket_depth && *cp == '}')
 705                        bracket_depth--;
 706                else if (!bracket_depth && *cp == ':')
 707                        break;
 708        }
 709        if (*cp == ':') {
 710                unsigned char tree_sha1[20];
 711                if (!get_sha1_1(name, cp-name, tree_sha1))
 712                        return get_tree_entry(tree_sha1, cp+1, sha1,
 713                                              mode);
 714        }
 715        return ret;
 716}