Andrew's git / gitweb.git / sha1_name.c
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sha1_name.con commit Merge branch 'master' into ph/strbuf (39bd2eb)
   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
 242static const char *ref_fmt[] = {
 243        "%.*s",
 244        "refs/%.*s",
 245        "refs/tags/%.*s",
 246        "refs/heads/%.*s",
 247        "refs/remotes/%.*s",
 248        "refs/remotes/%.*s/HEAD",
 249        NULL
 250};
 251
 252int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
 253{
 254        const char **p, *r;
 255        int refs_found = 0;
 256
 257        *ref = NULL;
 258        for (p = ref_fmt; *p; p++) {
 259                unsigned char sha1_from_ref[20];
 260                unsigned char *this_result;
 261
 262                this_result = refs_found ? sha1_from_ref : sha1;
 263                r = resolve_ref(mkpath(*p, len, str), this_result, 1, NULL);
 264                if (r) {
 265                        if (!refs_found++)
 266                                *ref = xstrdup(r);
 267                        if (!warn_ambiguous_refs)
 268                                break;
 269                }
 270        }
 271        return refs_found;
 272}
 273
 274int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 275{
 276        const char **p;
 277        int logs_found = 0;
 278
 279        *log = NULL;
 280        for (p = ref_fmt; *p; p++) {
 281                struct stat st;
 282                unsigned char hash[20];
 283                char path[PATH_MAX];
 284                const char *ref, *it;
 285
 286                strcpy(path, mkpath(*p, len, str));
 287                ref = resolve_ref(path, hash, 0, NULL);
 288                if (!ref)
 289                        continue;
 290                if (!stat(git_path("logs/%s", path), &st) &&
 291                    S_ISREG(st.st_mode))
 292                        it = path;
 293                else if (strcmp(ref, path) &&
 294                         !stat(git_path("logs/%s", ref), &st) &&
 295                         S_ISREG(st.st_mode))
 296                        it = ref;
 297                else
 298                        continue;
 299                if (!logs_found++) {
 300                        *log = xstrdup(it);
 301                        hashcpy(sha1, hash);
 302                }
 303                if (!warn_ambiguous_refs)
 304                        break;
 305        }
 306        return logs_found;
 307}
 308
 309static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 310{
 311        static const char *warning = "warning: refname '%.*s' is ambiguous.\n";
 312        char *real_ref = NULL;
 313        int refs_found = 0;
 314        int at, reflog_len;
 315
 316        if (len == 40 && !get_sha1_hex(str, sha1))
 317                return 0;
 318
 319        /* basic@{time or number} format to query ref-log */
 320        reflog_len = at = 0;
 321        if (str[len-1] == '}') {
 322                for (at = 0; at < len - 1; at++) {
 323                        if (str[at] == '@' && str[at+1] == '{') {
 324                                reflog_len = (len-1) - (at+2);
 325                                len = at;
 326                                break;
 327                        }
 328                }
 329        }
 330
 331        /* Accept only unambiguous ref paths. */
 332        if (len && ambiguous_path(str, len))
 333                return -1;
 334
 335        if (!len && reflog_len) {
 336                /* allow "@{...}" to mean the current branch reflog */
 337                refs_found = dwim_ref("HEAD", 4, sha1, &real_ref);
 338        } else if (reflog_len)
 339                refs_found = dwim_log(str, len, sha1, &real_ref);
 340        else
 341                refs_found = dwim_ref(str, len, sha1, &real_ref);
 342
 343        if (!refs_found)
 344                return -1;
 345
 346        if (warn_ambiguous_refs && refs_found > 1)
 347                fprintf(stderr, warning, len, str);
 348
 349        if (reflog_len) {
 350                int nth, i;
 351                unsigned long at_time;
 352                unsigned long co_time;
 353                int co_tz, co_cnt;
 354
 355                /* Is it asking for N-th entry, or approxidate? */
 356                for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 357                        char ch = str[at+2+i];
 358                        if ('0' <= ch && ch <= '9')
 359                                nth = nth * 10 + ch - '0';
 360                        else
 361                                nth = -1;
 362                }
 363                if (0 <= nth)
 364                        at_time = 0;
 365                else
 366                        at_time = approxidate(str + at + 2);
 367                if (read_ref_at(real_ref, at_time, nth, sha1, NULL,
 368                                &co_time, &co_tz, &co_cnt)) {
 369                        if (at_time)
 370                                fprintf(stderr,
 371                                        "warning: Log for '%.*s' only goes "
 372                                        "back to %s.\n", len, str,
 373                                        show_date(co_time, co_tz, DATE_RFC2822));
 374                        else
 375                                fprintf(stderr,
 376                                        "warning: Log for '%.*s' only has "
 377                                        "%d entries.\n", len, str, co_cnt);
 378                }
 379        }
 380
 381        free(real_ref);
 382        return 0;
 383}
 384
 385static int get_sha1_1(const char *name, int len, unsigned char *sha1);
 386
 387static int get_parent(const char *name, int len,
 388                      unsigned char *result, int idx)
 389{
 390        unsigned char sha1[20];
 391        int ret = get_sha1_1(name, len, sha1);
 392        struct commit *commit;
 393        struct commit_list *p;
 394
 395        if (ret)
 396                return ret;
 397        commit = lookup_commit_reference(sha1);
 398        if (!commit)
 399                return -1;
 400        if (parse_commit(commit))
 401                return -1;
 402        if (!idx) {
 403                hashcpy(result, commit->object.sha1);
 404                return 0;
 405        }
 406        p = commit->parents;
 407        while (p) {
 408                if (!--idx) {
 409                        hashcpy(result, p->item->object.sha1);
 410                        return 0;
 411                }
 412                p = p->next;
 413        }
 414        return -1;
 415}
 416
 417static int get_nth_ancestor(const char *name, int len,
 418                            unsigned char *result, int generation)
 419{
 420        unsigned char sha1[20];
 421        int ret = get_sha1_1(name, len, sha1);
 422        if (ret)
 423                return ret;
 424
 425        while (generation--) {
 426                struct commit *commit = lookup_commit_reference(sha1);
 427
 428                if (!commit || parse_commit(commit) || !commit->parents)
 429                        return -1;
 430                hashcpy(sha1, commit->parents->item->object.sha1);
 431        }
 432        hashcpy(result, sha1);
 433        return 0;
 434}
 435
 436static int peel_onion(const char *name, int len, unsigned char *sha1)
 437{
 438        unsigned char outer[20];
 439        const char *sp;
 440        unsigned int expected_type = 0;
 441        struct object *o;
 442
 443        /*
 444         * "ref^{type}" dereferences ref repeatedly until you cannot
 445         * dereference anymore, or you get an object of given type,
 446         * whichever comes first.  "ref^{}" means just dereference
 447         * tags until you get a non-tag.  "ref^0" is a shorthand for
 448         * "ref^{commit}".  "commit^{tree}" could be used to find the
 449         * top-level tree of the given commit.
 450         */
 451        if (len < 4 || name[len-1] != '}')
 452                return -1;
 453
 454        for (sp = name + len - 1; name <= sp; sp--) {
 455                int ch = *sp;
 456                if (ch == '{' && name < sp && sp[-1] == '^')
 457                        break;
 458        }
 459        if (sp <= name)
 460                return -1;
 461
 462        sp++; /* beginning of type name, or closing brace for empty */
 463        if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
 464                expected_type = OBJ_COMMIT;
 465        else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
 466                expected_type = OBJ_TREE;
 467        else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
 468                expected_type = OBJ_BLOB;
 469        else if (sp[0] == '}')
 470                expected_type = OBJ_NONE;
 471        else
 472                return -1;
 473
 474        if (get_sha1_1(name, sp - name - 2, outer))
 475                return -1;
 476
 477        o = parse_object(outer);
 478        if (!o)
 479                return -1;
 480        if (!expected_type) {
 481                o = deref_tag(o, name, sp - name - 2);
 482                if (!o || (!o->parsed && !parse_object(o->sha1)))
 483                        return -1;
 484                hashcpy(sha1, o->sha1);
 485        }
 486        else {
 487                /* At this point, the syntax look correct, so
 488                 * if we do not get the needed object, we should
 489                 * barf.
 490                 */
 491
 492                while (1) {
 493                        if (!o || (!o->parsed && !parse_object(o->sha1)))
 494                                return -1;
 495                        if (o->type == expected_type) {
 496                                hashcpy(sha1, o->sha1);
 497                                return 0;
 498                        }
 499                        if (o->type == OBJ_TAG)
 500                                o = ((struct tag*) o)->tagged;
 501                        else if (o->type == OBJ_COMMIT)
 502                                o = &(((struct commit *) o)->tree->object);
 503                        else
 504                                return error("%.*s: expected %s type, but the object dereferences to %s type",
 505                                             len, name, typename(expected_type),
 506                                             typename(o->type));
 507                        if (!o->parsed)
 508                                parse_object(o->sha1);
 509                }
 510        }
 511        return 0;
 512}
 513
 514static int get_describe_name(const char *name, int len, unsigned char *sha1)
 515{
 516        const char *cp;
 517
 518        for (cp = name + len - 1; name + 2 <= cp; cp--) {
 519                char ch = *cp;
 520                if (hexval(ch) & ~0377) {
 521                        /* We must be looking at g in "SOMETHING-g"
 522                         * for it to be describe output.
 523                         */
 524                        if (ch == 'g' && cp[-1] == '-') {
 525                                cp++;
 526                                len -= cp - name;
 527                                return get_short_sha1(cp, len, sha1, 1);
 528                        }
 529                }
 530        }
 531        return -1;
 532}
 533
 534static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 535{
 536        int ret, has_suffix;
 537        const char *cp;
 538
 539        /* "name~3" is "name^^^",
 540         * "name~" and "name~0" are name -- not "name^0"!
 541         * "name^" is not "name^0"; it is "name^1".
 542         */
 543        has_suffix = 0;
 544        for (cp = name + len - 1; name <= cp; cp--) {
 545                int ch = *cp;
 546                if ('0' <= ch && ch <= '9')
 547                        continue;
 548                if (ch == '~' || ch == '^')
 549                        has_suffix = ch;
 550                break;
 551        }
 552
 553        if (has_suffix) {
 554                int num = 0;
 555                int len1 = cp - name;
 556                cp++;
 557                while (cp < name + len)
 558                        num = num * 10 + *cp++ - '0';
 559                if (has_suffix == '^') {
 560                        if (!num && len1 == len - 1)
 561                                num = 1;
 562                        return get_parent(name, len1, sha1, num);
 563                }
 564                /* else if (has_suffix == '~') -- goes without saying */
 565                return get_nth_ancestor(name, len1, sha1, num);
 566        }
 567
 568        ret = peel_onion(name, len, sha1);
 569        if (!ret)
 570                return 0;
 571
 572        ret = get_sha1_basic(name, len, sha1);
 573        if (!ret)
 574                return 0;
 575
 576        /* It could be describe output that is "SOMETHING-gXXXX" */
 577        ret = get_describe_name(name, len, sha1);
 578        if (!ret)
 579                return 0;
 580
 581        return get_short_sha1(name, len, sha1, 0);
 582}
 583
 584static int handle_one_ref(const char *path,
 585                const unsigned char *sha1, int flag, void *cb_data)
 586{
 587        struct commit_list **list = cb_data;
 588        struct object *object = parse_object(sha1);
 589        if (!object)
 590                return 0;
 591        if (object->type == OBJ_TAG)
 592                object = deref_tag(object, path, strlen(path));
 593        if (object->type != OBJ_COMMIT)
 594                return 0;
 595        insert_by_date((struct commit *)object, list);
 596        return 0;
 597}
 598
 599/*
 600 * This interprets names like ':/Initial revision of "git"' by searching
 601 * through history and returning the first commit whose message starts
 602 * with the given string.
 603 *
 604 * For future extension, ':/!' is reserved. If you want to match a message
 605 * beginning with a '!', you have to repeat the exclamation mark.
 606 */
 607
 608#define ONELINE_SEEN (1u<<20)
 609static int get_sha1_oneline(const char *prefix, unsigned char *sha1)
 610{
 611        struct commit_list *list = NULL, *backup = NULL, *l;
 612        int retval = -1;
 613
 614        if (prefix[0] == '!') {
 615                if (prefix[1] != '!')
 616                        die ("Invalid search pattern: %s", prefix);
 617                prefix++;
 618        }
 619        if (!save_commit_buffer)
 620                return error("Could not expand oneline-name.");
 621        for_each_ref(handle_one_ref, &list);
 622        for (l = list; l; l = l->next)
 623                commit_list_insert(l->item, &backup);
 624        while (list) {
 625                char *p;
 626                struct commit *commit;
 627
 628                commit = pop_most_recent_commit(&list, ONELINE_SEEN);
 629                parse_object(commit->object.sha1);
 630                if (!commit->buffer || !(p = strstr(commit->buffer, "\n\n")))
 631                        continue;
 632                if (!prefixcmp(p + 2, prefix)) {
 633                        hashcpy(sha1, commit->object.sha1);
 634                        retval = 0;
 635                        break;
 636                }
 637        }
 638        free_commit_list(list);
 639        for (l = backup; l; l = l->next)
 640                clear_commit_marks(l->item, ONELINE_SEEN);
 641        return retval;
 642}
 643
 644/*
 645 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
 646 * notably "xyz^" for "parent of xyz"
 647 */
 648int get_sha1(const char *name, unsigned char *sha1)
 649{
 650        unsigned unused;
 651        return get_sha1_with_mode(name, sha1, &unused);
 652}
 653
 654int get_sha1_with_mode(const char *name, unsigned char *sha1, unsigned *mode)
 655{
 656        int ret, bracket_depth;
 657        int namelen = strlen(name);
 658        const char *cp;
 659
 660        *mode = S_IFINVALID;
 661        ret = get_sha1_1(name, namelen, sha1);
 662        if (!ret)
 663                return ret;
 664        /* sha1:path --> object name of path in ent sha1
 665         * :path -> object name of path in index
 666         * :[0-3]:path -> object name of path in index at stage
 667         */
 668        if (name[0] == ':') {
 669                int stage = 0;
 670                struct cache_entry *ce;
 671                int pos;
 672                if (namelen > 2 && name[1] == '/')
 673                        return get_sha1_oneline(name + 2, sha1);
 674                if (namelen < 3 ||
 675                    name[2] != ':' ||
 676                    name[1] < '0' || '3' < name[1])
 677                        cp = name + 1;
 678                else {
 679                        stage = name[1] - '0';
 680                        cp = name + 3;
 681                }
 682                namelen = namelen - (cp - name);
 683                if (!active_cache)
 684                        read_cache();
 685                pos = cache_name_pos(cp, namelen);
 686                if (pos < 0)
 687                        pos = -pos - 1;
 688                while (pos < active_nr) {
 689                        ce = active_cache[pos];
 690                        if (ce_namelen(ce) != namelen ||
 691                            memcmp(ce->name, cp, namelen))
 692                                break;
 693                        if (ce_stage(ce) == stage) {
 694                                hashcpy(sha1, ce->sha1);
 695                                *mode = ntohl(ce->ce_mode);
 696                                return 0;
 697                        }
 698                        pos++;
 699                }
 700                return -1;
 701        }
 702        for (cp = name, bracket_depth = 0; *cp; cp++) {
 703                if (*cp == '{')
 704                        bracket_depth++;
 705                else if (bracket_depth && *cp == '}')
 706                        bracket_depth--;
 707                else if (!bracket_depth && *cp == ':')
 708                        break;
 709        }
 710        if (*cp == ':') {
 711                unsigned char tree_sha1[20];
 712                if (!get_sha1_1(name, cp-name, tree_sha1))
 713                        return get_tree_entry(tree_sha1, cp+1, sha1,
 714                                              mode);
 715        }
 716        return ret;
 717}