Andrew's git / gitweb.git / sha1_name.c
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sha1_name.con commit Make sure git_connect() always give two file descriptors. (ec587fd)
   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
 238int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
 239{
 240        static const char *fmt[] = {
 241                "%.*s",
 242                "refs/%.*s",
 243                "refs/tags/%.*s",
 244                "refs/heads/%.*s",
 245                "refs/remotes/%.*s",
 246                "refs/remotes/%.*s/HEAD",
 247                NULL
 248        };
 249        const char **p, *r;
 250        int refs_found = 0;
 251
 252        *ref = NULL;
 253        for (p = fmt; *p; p++) {
 254                unsigned char sha1_from_ref[20];
 255                unsigned char *this_result;
 256
 257                this_result = refs_found ? sha1_from_ref : sha1;
 258                r = resolve_ref(mkpath(*p, len, str), this_result, 1, NULL);
 259                if (r) {
 260                        if (!refs_found++)
 261                                *ref = xstrdup(r);
 262                        if (!warn_ambiguous_refs)
 263                                break;
 264                }
 265        }
 266        return refs_found;
 267}
 268
 269static int get_sha1_basic(const char *str, int len, unsigned char *sha1)
 270{
 271        static const char *warning = "warning: refname '%.*s' is ambiguous.\n";
 272        char *real_ref = NULL;
 273        int refs_found = 0;
 274        int at, reflog_len;
 275
 276        if (len == 40 && !get_sha1_hex(str, sha1))
 277                return 0;
 278
 279        /* basic@{time or number} format to query ref-log */
 280        reflog_len = at = 0;
 281        if (str[len-1] == '}') {
 282                for (at = 1; at < len - 1; at++) {
 283                        if (str[at] == '@' && str[at+1] == '{') {
 284                                reflog_len = (len-1) - (at+2);
 285                                len = at;
 286                                break;
 287                        }
 288                }
 289        }
 290
 291        /* Accept only unambiguous ref paths. */
 292        if (ambiguous_path(str, len))
 293                return -1;
 294
 295        refs_found = dwim_ref(str, len, sha1, &real_ref);
 296
 297        if (!refs_found)
 298                return -1;
 299
 300        if (warn_ambiguous_refs && refs_found > 1)
 301                fprintf(stderr, warning, len, str);
 302
 303        if (reflog_len) {
 304                /* Is it asking for N-th entry, or approxidate? */
 305                int nth, i;
 306                unsigned long at_time;
 307                unsigned long co_time;
 308                int co_tz, co_cnt;
 309
 310                for (i = nth = 0; 0 <= nth && i < reflog_len; i++) {
 311                        char ch = str[at+2+i];
 312                        if ('0' <= ch && ch <= '9')
 313                                nth = nth * 10 + ch - '0';
 314                        else
 315                                nth = -1;
 316                }
 317                if (0 <= nth)
 318                        at_time = 0;
 319                else
 320                        at_time = approxidate(str + at + 2);
 321                if (read_ref_at(real_ref, at_time, nth, sha1, NULL,
 322                                &co_time, &co_tz, &co_cnt)) {
 323                        if (at_time)
 324                                fprintf(stderr,
 325                                        "warning: Log for '%.*s' only goes "
 326                                        "back to %s.\n", len, str,
 327                                        show_rfc2822_date(co_time, co_tz));
 328                        else
 329                                fprintf(stderr,
 330                                        "warning: Log for '%.*s' only has "
 331                                        "%d entries.\n", len, str, co_cnt);
 332                }
 333        }
 334
 335        free(real_ref);
 336        return 0;
 337}
 338
 339static int get_sha1_1(const char *name, int len, unsigned char *sha1);
 340
 341static int get_parent(const char *name, int len,
 342                      unsigned char *result, int idx)
 343{
 344        unsigned char sha1[20];
 345        int ret = get_sha1_1(name, len, sha1);
 346        struct commit *commit;
 347        struct commit_list *p;
 348
 349        if (ret)
 350                return ret;
 351        commit = lookup_commit_reference(sha1);
 352        if (!commit)
 353                return -1;
 354        if (parse_commit(commit))
 355                return -1;
 356        if (!idx) {
 357                hashcpy(result, commit->object.sha1);
 358                return 0;
 359        }
 360        p = commit->parents;
 361        while (p) {
 362                if (!--idx) {
 363                        hashcpy(result, p->item->object.sha1);
 364                        return 0;
 365                }
 366                p = p->next;
 367        }
 368        return -1;
 369}
 370
 371static int get_nth_ancestor(const char *name, int len,
 372                            unsigned char *result, int generation)
 373{
 374        unsigned char sha1[20];
 375        int ret = get_sha1_1(name, len, sha1);
 376        if (ret)
 377                return ret;
 378
 379        while (generation--) {
 380                struct commit *commit = lookup_commit_reference(sha1);
 381
 382                if (!commit || parse_commit(commit) || !commit->parents)
 383                        return -1;
 384                hashcpy(sha1, commit->parents->item->object.sha1);
 385        }
 386        hashcpy(result, sha1);
 387        return 0;
 388}
 389
 390static int peel_onion(const char *name, int len, unsigned char *sha1)
 391{
 392        unsigned char outer[20];
 393        const char *sp;
 394        unsigned int expected_type = 0;
 395        struct object *o;
 396
 397        /*
 398         * "ref^{type}" dereferences ref repeatedly until you cannot
 399         * dereference anymore, or you get an object of given type,
 400         * whichever comes first.  "ref^{}" means just dereference
 401         * tags until you get a non-tag.  "ref^0" is a shorthand for
 402         * "ref^{commit}".  "commit^{tree}" could be used to find the
 403         * top-level tree of the given commit.
 404         */
 405        if (len < 4 || name[len-1] != '}')
 406                return -1;
 407
 408        for (sp = name + len - 1; name <= sp; sp--) {
 409                int ch = *sp;
 410                if (ch == '{' && name < sp && sp[-1] == '^')
 411                        break;
 412        }
 413        if (sp <= name)
 414                return -1;
 415
 416        sp++; /* beginning of type name, or closing brace for empty */
 417        if (!strncmp(commit_type, sp, 6) && sp[6] == '}')
 418                expected_type = OBJ_COMMIT;
 419        else if (!strncmp(tree_type, sp, 4) && sp[4] == '}')
 420                expected_type = OBJ_TREE;
 421        else if (!strncmp(blob_type, sp, 4) && sp[4] == '}')
 422                expected_type = OBJ_BLOB;
 423        else if (sp[0] == '}')
 424                expected_type = OBJ_NONE;
 425        else
 426                return -1;
 427
 428        if (get_sha1_1(name, sp - name - 2, outer))
 429                return -1;
 430
 431        o = parse_object(outer);
 432        if (!o)
 433                return -1;
 434        if (!expected_type) {
 435                o = deref_tag(o, name, sp - name - 2);
 436                if (!o || (!o->parsed && !parse_object(o->sha1)))
 437                        return -1;
 438                hashcpy(sha1, o->sha1);
 439        }
 440        else {
 441                /* At this point, the syntax look correct, so
 442                 * if we do not get the needed object, we should
 443                 * barf.
 444                 */
 445
 446                while (1) {
 447                        if (!o || (!o->parsed && !parse_object(o->sha1)))
 448                                return -1;
 449                        if (o->type == expected_type) {
 450                                hashcpy(sha1, o->sha1);
 451                                return 0;
 452                        }
 453                        if (o->type == OBJ_TAG)
 454                                o = ((struct tag*) o)->tagged;
 455                        else if (o->type == OBJ_COMMIT)
 456                                o = &(((struct commit *) o)->tree->object);
 457                        else
 458                                return error("%.*s: expected %s type, but the object dereferences to %s type",
 459                                             len, name, typename(expected_type),
 460                                             typename(o->type));
 461                        if (!o->parsed)
 462                                parse_object(o->sha1);
 463                }
 464        }
 465        return 0;
 466}
 467
 468static int get_describe_name(const char *name, int len, unsigned char *sha1)
 469{
 470        const char *cp;
 471
 472        for (cp = name + len - 1; name + 2 <= cp; cp--) {
 473                char ch = *cp;
 474                if (hexval(ch) & ~0377) {
 475                        /* We must be looking at g in "SOMETHING-g"
 476                         * for it to be describe output.
 477                         */
 478                        if (ch == 'g' && cp[-1] == '-') {
 479                                cp++;
 480                                len -= cp - name;
 481                                return get_short_sha1(cp, len, sha1, 1);
 482                        }
 483                }
 484        }
 485        return -1;
 486}
 487
 488static int get_sha1_1(const char *name, int len, unsigned char *sha1)
 489{
 490        int ret, has_suffix;
 491        const char *cp;
 492
 493        /* "name~3" is "name^^^",
 494         * "name~" and "name~0" are name -- not "name^0"!
 495         * "name^" is not "name^0"; it is "name^1".
 496         */
 497        has_suffix = 0;
 498        for (cp = name + len - 1; name <= cp; cp--) {
 499                int ch = *cp;
 500                if ('0' <= ch && ch <= '9')
 501                        continue;
 502                if (ch == '~' || ch == '^')
 503                        has_suffix = ch;
 504                break;
 505        }
 506
 507        if (has_suffix) {
 508                int num = 0;
 509                int len1 = cp - name;
 510                cp++;
 511                while (cp < name + len)
 512                        num = num * 10 + *cp++ - '0';
 513                if (has_suffix == '^') {
 514                        if (!num && len1 == len - 1)
 515                                num = 1;
 516                        return get_parent(name, len1, sha1, num);
 517                }
 518                /* else if (has_suffix == '~') -- goes without saying */
 519                return get_nth_ancestor(name, len1, sha1, num);
 520        }
 521
 522        ret = peel_onion(name, len, sha1);
 523        if (!ret)
 524                return 0;
 525
 526        ret = get_sha1_basic(name, len, sha1);
 527        if (!ret)
 528                return 0;
 529
 530        /* It could be describe output that is "SOMETHING-gXXXX" */
 531        ret = get_describe_name(name, len, sha1);
 532        if (!ret)
 533                return 0;
 534
 535        return get_short_sha1(name, len, sha1, 0);
 536}
 537
 538/*
 539 * This is like "get_sha1_basic()", except it allows "sha1 expressions",
 540 * notably "xyz^" for "parent of xyz"
 541 */
 542int get_sha1(const char *name, unsigned char *sha1)
 543{
 544        int ret, bracket_depth;
 545        unsigned unused;
 546        int namelen = strlen(name);
 547        const char *cp;
 548
 549        prepare_alt_odb();
 550        ret = get_sha1_1(name, namelen, sha1);
 551        if (!ret)
 552                return ret;
 553        /* sha1:path --> object name of path in ent sha1
 554         * :path -> object name of path in index
 555         * :[0-3]:path -> object name of path in index at stage
 556         */
 557        if (name[0] == ':') {
 558                int stage = 0;
 559                struct cache_entry *ce;
 560                int pos;
 561                if (namelen < 3 ||
 562                    name[2] != ':' ||
 563                    name[1] < '0' || '3' < name[1])
 564                        cp = name + 1;
 565                else {
 566                        stage = name[1] - '0';
 567                        cp = name + 3;
 568                }
 569                namelen = namelen - (cp - name);
 570                if (!active_cache)
 571                        read_cache();
 572                if (active_nr < 0)
 573                        return -1;
 574                pos = cache_name_pos(cp, namelen);
 575                if (pos < 0)
 576                        pos = -pos - 1;
 577                while (pos < active_nr) {
 578                        ce = active_cache[pos];
 579                        if (ce_namelen(ce) != namelen ||
 580                            memcmp(ce->name, cp, namelen))
 581                                break;
 582                        if (ce_stage(ce) == stage) {
 583                                hashcpy(sha1, ce->sha1);
 584                                return 0;
 585                        }
 586                        pos++;
 587                }
 588                return -1;
 589        }
 590        for (cp = name, bracket_depth = 0; *cp; cp++) {
 591                if (*cp == '{')
 592                        bracket_depth++;
 593                else if (bracket_depth && *cp == '}')
 594                        bracket_depth--;
 595                else if (!bracket_depth && *cp == ':')
 596                        break;
 597        }
 598        if (*cp == ':') {
 599                unsigned char tree_sha1[20];
 600                if (!get_sha1_1(name, cp-name, tree_sha1))
 601                        return get_tree_entry(tree_sha1, cp+1, sha1,
 602                                              &unused);
 603        }
 604        return ret;
 605}